ES3045833T3 - Improved expanded slit sheet cushioning products with novel slit pattern and paper properties - Google Patents

Abstract

In preferred embodiments, the present invention provides substantially improved slotted sheet cushioning products through the advantageous combination of novel paper properties with novel slotting patterns to achieve enhanced characteristics. In some illustrative, non-limiting example embodiments, the cushioning products of the present invention may include, for example, a novel slotted sheet material in combination with extensible paper used as a cushioning pad or as cushioning within an envelope. The cushioning product may be substantially stronger, but also, for example, thinner for better space utilization.

Description

[0001] DESCRIPTION

[0003] Improved expanded slit sheet cushioning products with a novel slit pattern and novel paper properties

[0005] Background

[0007] Technical field of the invention

[0009] The present invention relates to the use of expandable slit-sheet material to provide a cushioning product. In preferred embodiments, the present invention provides substantially improved slit-sheet cushioning products by advantageously combining novel paper properties with novel slit patterns to enhance functions and features. In some illustrative and non-limiting example embodiments, the cushioning products of the present invention may include, for example, a novel slit-sheet material in combination with extensible paper employed, for example, as a cushioning pad or as cushioning within an envelope product, wherein the cushioning product may be substantially stronger, yet, for example, thinner for better space utilization.

[0011] Technique related to expanded slit sheet paper

[0013] Additional information relating to the paper that can be used in the present invention, the slit patterns, and the expansion process can be found in U.S. patents a) 5,538,778, b) 5,667,871, c) 5,688,578, d) 5,782,735, e) 3,908,071, f) 3,104,197, g) 3,220,116, h) 3,266,972, i) 3,269,393, j) 3,908,071, k) 6,024,832, l) 6,458,447, and m) 6,712,930, and in U.S. application serial no. 14/901,977, as well as in the PCT application No. WO1984002936A1, and in the published United States patent applications No. US 2002/0060034, US 2007/0240841.

[0015] In preferred embodiments, the term "expandable," as applied to sheets of paper, refers to paper with a slit pattern that permits expansion, as described, for example, in U.S. Patent Nos. (a) 5,538,778, (b) 5,667,871, (c) 5,688,578, (d) 5,782,735, and (e) 10,226,907 and PCT Application No. PCT/US2014/054615. In preferred embodiments, a slit pattern has been configured to expand the paper longitudinally, with a consequent decrease in its width. In some embodiments, the slit pattern produces a paper that increases in length due to the slit pattern when processed in an expander, such as, for example, an expander of the type described in any of the following PCT and US applications: (a) 2017/0203866, (b) 2018/022266, (c) 2018/0127197 and (d) PCT/US2014/054615.

[0017] U.S. Patents 5,667,871 and 5,688,578, relating to "slit-sheet packaging material," describe the use of several individual slits forming parallel, spaced rows, forming an expanded hexagonal sheet with and without a separator sheet. Machinery is required to stretch the paper into its three-dimensional shape at the customer's location, as described in U.S. Patent 5,538,778, which describes the method and apparatus for producing the expansion of the slit-sheet material at the packaging site. U.S. Patent 5,782,735 describes an expander for expanding the slit-sheet material of U.S. Patents 5,667,871 and 5,688,578.

[0019] For reference, Figures 3(A) and 3(B) correspond to Figures 1 and 3 of U.S. Patent 5,667,871 (patent '871). These figures depict the existing expandable "slit sheet" paper structure. As explained in patent '871:

[0021] "The slit paper, generally designated as 10, is illustrated in Figure [3(A)] as it would come off the slitting machine. The sheets may be formed on a flat slitter and produced directly as rectangular sheets, or on a rotary slitter and cut into individual sheets or stored directly as a continuous sheet in roll form. The flexible sheet 10 is preferably made from recycled paper only, with the paper grain in the direction of arrow A. The flexible sheet 10 has slits 14 and 16 parallel to the edges 22 and 24 of the flexible sheet 12 and perpendicular to the paper grain. The slits 14 and 16 are arranged in rows and separated from each other by the ground 20 and the legs 21 [shown in Figure 3(B)]. The ground 20 is of uniform size and provides the support necessary to prevent the paper from tearing when opened." The cushioning effect is produced by the flexing of the ground and legs under load. Therefore, the ground 20 must be of sufficient size to provide cushioning. The spacing between the rows of slits 14 and 16 must also be sufficient to prevent the paper from tearing. The offset position of the rows of slits 14 and 16 provides elasticity to the paper when it opens, a matter that will be discussed in detail later. The presence of partial slits 14 and 16 at the ends 25 and 18 of the flexible sheet 10 does not affect the efficiency of the slit paper 10. The flexible sheet 10, when flat, is in the foreground.

[0023] “When expanded, the expanded sheet, generally referred to as 12, is made up of hexagonal cells 26, legs 21, and ground areas 20, as illustrated in figure [3(B)]. Preferably, at least the majority of the ground areas 20 lie in several parallel planes. The planes of the ground areas 20 form an angle of at least about 45 degrees with the plane of the sheet in its flat form.”

[0025] "The longitudinal cutting operation, in which slits are made in the sheet material, can take various forms. In one embodiment, slits are provided in rectangular sheets, with the total number of slits being made in a single action. The term 'rectangular' should be understood as rectangles with four equal sides, i.e., squares. When the sheet material is subjected to rotary cutting or slitting, the pressure required for the cutting action is significantly less than that required for flat cutting, since essentially only one or a few rows of slits are cut simultaneously. Unlike structures and systems of the prior art, simultaneous expansion with slitting is undesirable. Therefore, a critical balance must be achieved between the resistance to cell opening during the rewinding stage and the ease of cell opening during the expansion stage. By achieving this critical balance and producing an unexpanded flat sheet, the sheet material has an effective thickness that is up to one-twentieth the thickness of a sheet of expanded material." The compact configuration optimizes shipping and storage.

[0027] In preferred embodiments, the term "slit sheet" refers to an expandable sheet of paper with a slit pattern. The following is a verbatim quotation from U.S. Patent 5,667,871 (the '871 patent).

[0028] First, section 10, lines 13-48, of patent '871 explains:

[0030] "The slit length and the ratio of the ground intervals between slits affect the dimensions of the polygons formed during expansion. The greater the ratio of slit length to interval length, the greater the maximum angle that can be formed between the sheet plane and the planes of the ground areas. The greater the uniformity of the shape and size of the polygonal open areas formed and the angle of inclination of the ground areas with respect to the flat sheet, the greater the degree of interlacing of the ground areas. Interlacing of ground areas, i.e., nesting of sheet layers, reduces the effective thickness of the sheets. However, the net effect is still a dramatic increase in the effective sheet thickness. For example, 0.2 mm thick paper with a slit pattern having a 1.27 cm slit, a 0.48 cm gap between slits, and a 0.32 cm gap between rows, produces a soil measuring 0.63 cm by 0.48 cm that can expand to less than 0.63 cm thick and will have an effective net thickness for two layers, when nested, of approximately 0.95 cm. It is worth noting that the width of the soil is twice the width of the legs. The net effect is a useful thickness expansion of approximately 20 times the unexpanded thickness of the paper.

[0032] The longer the slit relative to the stiffness of the sheet material, the weaker the interlocking and damping effects will be due to the weakness of the expanded structure. If the slits are too small, expansion may be severely limited and damping excessively limited. This does not mean that the dimensions are strictly critical, but rather that they should be selected based on the paper's characteristics, such as the degree of stiffness and the required damping or energy absorption effects. Resistance to expansion increases with increasing ground area size. It should be understood that some resistance to opening is desired. The object rests on or comes into contact with the edge of the sheet formed by the slope of the ground areas, which transforms the perimeter of the openings into upper and lower edges.

[0034] Second, Section 10, lines 58-67 and Section 11, lines 1-6, of patent '871 explain in more detail: “As mentioned above, the dimensions of the slit can be varied to facilitate the opening process. A 1.59 cm slit, with a ground area of 0.48 cm by a row of 0.48 cm, opens very easily due to the reduction in the number of hexagons. By increasing the size of the hexagons and reducing their number, the stretched thickness was increased, resulting in a very workable wrapping material. This sizing increases the paper's yield and provides almost the same protection as the 1.27 cm slit. This sizing provides a more economical product that utilizes a greater quantity of post-consumer waste, while maintaining the integrity of the wrapping product.” The 1.27 cm cleft pattern, with 0.48 cm cleft by 0.32 cm row, produces a more protective wrapping due to the greater number of wrappings that can be made within the same volume. Therefore, a 1.13 kg vase dropped from a height of 30 cm, with only 1.27 cm of accumulated leaf thickness around the vase, can be protected with the 1.27 cm cleft pattern and 0.63 cm by 0.48 cm soil.

[0036] The present inventor's prior U.S. patent No. 10,226,907 (the '907 patent) shows a prior: "Packing material of expandable slit sheets that interlock when layered and expanded." In the '907 patent, the product includes several layers, each with a different slit pattern for "interlocking" between the different layers. As explained in section 2 of the '907 patent, "the different slit patterns, when expanded, produce a sloped ground area with the same number of rows per centimeter, but with different angles of slope, so that adjacent layers can interlock." While the '907 patent describes an example with a slit length of 1.02 centimeters for one of the layers, it is noteworthy that 1) this slit length of 1.02 centimeters is only used in conjunction with an adjacent layer having a greater slit length of 1.27 centimeters; 2) This reduced slit length is not used in conjunction with a reduced row spacing (i.e., the row spacing must be the same as that of the adjacent layer with a slit length of 1.27 centimeters). Therefore, patent '907 does not describe the improved slit sheet damping products of the present invention or their advantages.

[0038] The preferred embodiments of the present invention improve upon and overcome various problems and limitations of the related art.

[0040] Summary

[0042] The preferred embodiments surpass and improve upon the prior art and/or other related techniques. According to some embodiments of the invention, the use of a slit pattern that creates more cells per square meter provides greater crush resistance and resilience to cushion the items packed inside as a wrapper or when used as a pad for an envelope (including, in some illustrative preferred embodiments of an envelope, where the envelope includes at least one inner or outer layer of serrated paper).

[0044] In the most preferred embodiments, an expanded paper cushioning product is provided employing an improved slit arrangement, and wherein the expanded paper is an extensible paper.

[0046] In some preferred embodiments, the slit paper pattern advantageously features slits in the range of 0.76 to 1.14 centimeters (i.e., in the longitudinal dimension of the slits) and row spacing in the range of 0.286 to 0.428 centimeters (i.e., the distance between adjacent rows of slits). Preferably, these latter embodiments are made of extensible paper.

[0048] In some preferred embodiments, the slit paper has slits whose width is 1.14 cm plus 5%, minus 33% (i.e., here the slit width refers to the longitudinal dimension of the slits). More preferably, again, these latter embodiments are made of extensible paper.

[0050] In some preferred embodiments, the slit pattern advantageously produces an expandable slit paper with a number of legs per square meter at least 20% greater than that of slit paper with slit (cut) widths of 1.27 cm.

[0052] In some preferred embodiments, an expanded slit paper cushioning product of the present invention has a number of legs per square meter at least 15% greater than that of slit paper with slit (cut) widths of 1.27 cm. In some preferred embodiments, an expanded slit paper cushioning product of the present invention has a number of legs per square meter that is in the range of 20% to 50% greater than that of slit paper having slit (cut) widths of 1.27 cm.

[0054] Furthermore, although the present inventor has discovered new methods for improving the damping characteristics of expandable slit-sheet paper, which involve reducing the dimensions of the slit pattern, it is noteworthy that this reduction is not only infeasible with the previously mentioned expandable slit-sheet paper (i.e., it could not achieve such small sizes), but also contradicts the current understanding of the damping properties offered by such expandable slit-sheet papers. It is noteworthy that the damping of expandable slit-sheet paper is directly related to its width in the expanded state. Consequently, to improve damping, those skilled in the art have sought to increase this width of the expanded slit-sheet paper. However, the present inventor discovered methods for achieving smaller slit patterns (e.g., by using stretchable paper) and that such smaller slit patterns with such stretchable papers could, in fact, provide better cushioning despite the cushioning losses due to the reduction in the width of the stretchable slit sheet paper. Furthermore, the present inventor also discovered other desirable applications and uses of this novel stretchable slit sheet paper.

[0056] According to some preferred embodiments, a slit-sheet paper cushioning product is provided comprising: a slit-sheet paper having a slit pattern including several transverse slits forming several open cells when expanded in the machine direction, wherein the slit width ranges from 1.1 cm 5% to 1.1 cm - 33%, and said slit-sheet paper being formed from an extensible paper, designed to be extensible in both the machine direction and the transverse direction without said slit pattern; said extensible paper having an extensibility within the range of 3% to 20% in the machine direction.

[0058] According to some embodiments of the invention, a slit-sheet paper cushioning product is provided comprising: a paper sheet having a slit pattern comprising a plurality of slits extending in a transverse direction forming a plurality of open cells upon expansion in a machine direction, wherein the slit width is at least 10% less than 0.5 inches, and said slit-sheet paper is formed from extensible paper, designed to be extensible in both the machine and transverse directions without said slit pattern; said extensible paper having an extensibility within the range of 3 to 20% in the machine direction.

[0060] According to some preferred embodiments, a slit-sheet paper cushioning product is provided, comprising: at least one slit-sheet paper with a slit pattern including several transverse slits forming several open cells upon machine-direction expansion, wherein the slit width is at least 10% less than 0.5 inches. The slit-sheet paper is formed from an expandable paper that expands in an alternating-row expansion pattern including alternating rows with lower cell openings in the lower rows located on the underside of the expanded slit-sheet paper and with upper cell openings in the upper rows located on the upper side of the expanded slit-sheet paper. According to some embodiments, the slit-sheet paper is made from an extensible paper. According to some embodiments, the extensible paper is machine-direction extensible by at least 5%. According to some embodiments, the extensible paper is extensible in the transverse direction by at least 5%. According to some embodiments, the extensible paper is extensible in the machine direction and in the transverse direction without said slit pattern, said extensible paper having an extensibility of 3 to 20% in the machine direction.

[0062] In some embodiments, the slit blade includes spaces between rows of slits in the range of 0.286 to 0.428 centimeters. In some embodiments, the slit blade includes spaces between rows of slits less than 0.32 centimeters. In some embodiments, the slit blade includes spaces between rows of slits less than 0.286 centimeters. In some embodiments, the slit blade includes spaces between rows of slits less than 0.22225 centimeters. In some embodiments, the width of the slit is less than 1.016 centimeters. In some embodiments, the width of the slit is less than 0.889 centimeters. In some embodiments, the width of the slit is less than 0.762 centimeters.

[0064] In some embodiments, the slit-leaf paper is a roll of slit-leaf paper. In some embodiments, the roll of slit-leaf paper is supported by an expanding device adapted to rotatably hold the roll of slit-leaf paper for manual extraction and expansion of said slit-leaf paper from said roll. According to some embodiments, a method of using the slit-leaf paper cushioning product includes manually wrapping the expanded slit-leaf paper around an article, thereby creating several layers of expanded slit-leaf paper surrounding it for cushioning.

[0066] In some embodiments, slit-leaf paper is used inside the wall of an envelope for cushioning.

[0067] In some embodiments, the envelope includes a single layer of said slit-leaf paper within the envelope wall for cushioning, thereby reducing its thickness. In some embodiments, the envelope wall includes an outer paper layer located on a first side of said slit-leaf paper and an inner paper layer on a second side of said slit-leaf paper. In some embodiments, the outer paper layer and/or said inner paper layer include embossing.

[0069] In some embodiments, the slit-leaf paper forms an alternating row expansion pattern as it expands to form said plurality of open cells. In some embodiments, the slit-leaf paper is in the expanded state, with said plurality of open cells forming an alternating row expansion pattern. In some embodiments, the alternating row expansion pattern includes alternating rows with cell openings at the bottom of the lower rows located on the underside of the expanded slit-leaf paper, and with cell openings at the top of the upper rows located on the upper side of the expanded slit-leaf paper.

[0071] In some embodiments, the number of support legs is at least 20% greater than the number of support legs of a slit-sheet paper with 1.27 cm slits, so that the slit pattern, when expanded, generates more cells per square meter and provides greater crush resistance and resilience for cushioning than that provided by a slit-sheet paper with 1.27 cm slits.

[0073] According to some embodiments, the slit-leaf paper cushioning product is an envelope comprising at least one slit-leaf paper sheet in the expanded state; a first sheet of paper facing a first face of said slit-leaf paper sheet in the expanded state and fixed with respect to said at least one slit-leaf paper along at least a portion of the periphery of said expanded slit-leaf paper; a second sheet of paper facing an opposite face of said at least one slit-leaf paper in said expanded state and fixed with respect to said at least one slit-leaf paper along at least a portion of the periphery of said slit-leaf paper. In some embodiments, a) at least one of said first sheet of paper and said second sheet of paper are embossed sheets with a plurality of reliefs that inhibit the deformation of said first and second sheets of paper due to the contraction forces of said at least one slit-sheet paper in said expanded state; or b) said first sheet of paper and said second sheet of paper are non-embossed sheets that have a greater weight compared to the weight of said at least one slit-sheet paper in said expanded state, which inhibits the deformation of said first and second sheets of paper due to the contraction forces of said at least one slit-sheet paper in said expanded state.

[0074] According to some other embodiment of the present invention, a slit-sheet paper cushioning product is provided, comprising: at least one slit-sheet paper having a slit pattern including several transverse slits forming several open cells upon expansion in the machine direction. Said slit-sheet paper is formed from an expandable paper that expands in an alternating row expansion pattern including alternating rows with lower cell openings in the lower rows located on the underside of the expanded slit-sheet paper and with upper cell openings in the upper rows located on the upper side of the expanded slit-sheet paper. According to some embodiments, the slit-sheet paper is made from an extensible paper. According to some embodiments, the extensible paper is extensible in the machine direction by at least 5%. According to some embodiments, the extensible paper is extensible in the transverse direction by at least 5%. According to some embodiments, the extensible paper is extensible in the machine direction by at least 5% and in the transverse direction by at least 5%. According to some embodiments, the extensible paper is extensible in the machine direction by at least 6% and in the transverse direction by at least 6%. According to some embodiments, the extensible paper is extensible in the machine direction by at least 7% and in the transverse direction by at least 7%. According to some more preferred embodiments, the extensible paper is extensible in the machine direction by at least 8% and in the transverse direction by at least 8%. According to some embodiments, the extensible paper is extensible in the machine direction by between 5% and 15% and in the transverse direction by between 5% and 15%. According to some embodiments, the extensible paper is extensible in the machine direction by between 7% and 15% and in the transverse direction by between 7% and 15%. According to some embodiments, each slit is between 0.889 and 1.651 centimeters wide; according to some embodiments, each slit is between 1.143 and 1.397 centimeters wide. According to some embodiments, each slit is approximately 1.27 cm wide. According to some embodiments, each slit is less than 1.27 cm wide. According to some embodiments, each slit is less than 1.14 cm wide. According to some embodiments, each slit is less than 1.14 cm wide.

[0075] The above and/or other aspects, features, and advantages of the various embodiments will be better understood from the following description together with the accompanying figures. Various embodiments may include and/or exclude different aspects, features, and/or advantages as appropriate. Furthermore, various embodiments may combine one or more aspects or features of other embodiments as appropriate. Descriptions of the aspects, features, and/or advantages of particular embodiments should not be construed as limiting other embodiments or claims.

[0077] Brief description of the drawings

[0079] Preferred embodiments of the present invention are shown by way of example, and not of limitation, in the accompanying figures, in which:

[0081] Figure 1 is an explanatory flat view showing two slit patterns and the resulting number of cells per square meter;

[0083] Figure 2 is an explanatory side view of the cell structure of the expanded slit sheet material representing some embodiments of the present invention compared to the prior art;

[0085] Figure 3(A) is a plan view of an illustrative slit sheet paper according to the prior art in an unexpanded state, specifically corresponding to Figure 1 of U.S. Patent No. 5,667,871, and Figure 3(B) is a plan view of an illustrative slit sheet paper according to the prior art in an expanded state, specifically corresponding to Figure 3 of U.S. Patent No. 5,667,871;

[0087] Figure 4(A) shows a top plan view of a sample of expanded slit sheet paper, using Kraft paper, which opens similarly to that shown in Figure 3(B).

[0089] Figure 4(B) shows a top view of the same expanded slit-sheet paper shown in Figure 4(A), taken at an angle to the plane of the expanded paper so that one looks directly into the expanded cells of the paper.

[0091] Figure 4(C) shows a top view of the same expanded slit-sheet paper shown in Figures 4(A) and 4(B), but taken at an angle to the plane of the expanded paper opposite to the angle shown in Figure 4(B).

[0093] Figure 4(D) shows a top view of the same expanded slit-sheet paper shown in Figures 4(A)-4(C), but taken from an angle with respect to the plane of the expanded paper from a position below the plane of the paper near the bottom end of Figure 4(D).

[0094] Figure 5(A) shows a top plan view of a novel alternating row expansion pattern of an expanded slit sheet paper, according to some preferred embodiments of the present invention.

[0096] Figure 5(B) shows a top view of the expanded slit-sheet paper shown in Figure 5(A), taken at an angle to the plane of the paper, so that it is viewed from the upper right of the view in Figure 5(A).

[0098] Figure 5(C) shows a top view of the expanded slit-sheet paper shown in Figure 5(A), taken at an angle to the plane of the paper, so that it is viewed from the top left of the view in Figure 5(A) and at a lower angle than shown in Figure 5(B).

[0100] Figure 5(D) shows a top view of the expanded slit sheet paper shown in Figure 5(A).

[0101] 5(A) taken at an angle with respect to the plane of the paper, so that the cut sheet of paper can be observed expanded at an angle from a lower side of the view in Figure 5(A);

[0103] Figure 5(E) shows a rear plan view of the expanded slit-leaf paper shown in Figure 5(A) from the opposite side (i.e., looking up from behind the expanded slit-leaf paper in the view of Figure 5(A));

[0105] Figure 5(F) shows a rear view of the expanded slit-leaf paper shown in Figure 5(A) from the opposite side (i.e., looking up from behind the expanded slit-leaf paper in the view of Figure 5(A)) and taken at an angle to the plane of the paper, so that it is viewed from the lower left of Figure 5(E);

[0107] Figure 5(G) shows a rear view of the expanded slit-leaf paper shown in Figure 5(A) from a direction similar to that in Figure 5(F), except at an angle closer to the plane of the expanded slit-leaf paper, to more clearly represent the alternating row pattern of the expanded slit-leaf paper sheet.

[0109] Figure 5(H) shows a rear view of the expanded slit-leaf paper shown in Figure 5(A), taken at an angle to the plane of the paper, so that the expanded slit-leaf paper can be observed from the top of the view in Figure 5(E).

[0111] Figures 6(A) to 6(C) show the formation of the alternating row expansion pattern according to preferred embodiments of the invention. Figure 6(A) shows an illustrative slit pattern formed within a sheet of paper; Figure 6(B) shows the slit pattern of Figure 6(A) with regions of the paper before expansion highlighted for reference. Figure 6(C) is a photograph of an illustrative expanded slit sheet paper with a slit pattern similar to that shown in Figure 6(B) in the expanded state.

[0113] Figures 7(A) and 7(B) are explanatory diagrams demonstrating the increase in cell concentration with the reduction of slit lengths, according to some preferred embodiments of the invention.

[0115] Figures 8(A) and 8(B) correspond to Figures 1 and 7, respectively, of U.S. Patent Application Serial No. 16/531,017, wherein Figure 8(A) shows a cross-sectional side view of an illustrative pad, according to some preferred embodiments, used to form an envelope, and Figure 8(B) is a perspective view of an envelope formed from the envelope pad of Figure 8(A), according to some illustrative embodiments.

[0116] In the accompanying drawings, Figures 4(A)-4(D), 5(A)-5(G), and 6(C) are photographs of actual products. Accordingly, these photographs show illustrative examples to scale; thus, these figures show illustrative examples to scale, and the angles and relative dimensions shown therein are the same as in those illustrative examples. Therefore, for example, the angles of the ground, legs, and other parts of the expanded slit-sheet paper may, in some embodiments, be those shown in those figures. Furthermore, in some alternative embodiments, those angles and relative dimensions shown may vary slightly, for example, by plus or minus 15% in some examples, or by plus or minus 10% in other examples.

[0118] Detailed description of preferred realizations

[0120] Although the present invention can be embodied in various forms, the illustrative embodiments described herein are understood to be examples of the principles of the invention and are not intended to limit the invention to the preferred embodiments described or illustrated herein.

[0122] Introduction to preferred realizations

[0124] In preferred embodiments, the present invention provides substantially improved slit-sheet cushioning products by advantageously combining novel paper properties with novel slit patterns to enhance functions and features. In some illustrative and non-limiting example embodiments, the cushioning products of the present invention may include, for example, a novel slit-sheet material in combination with extensible paper employed, for example, as a cushioning pad or as cushioning within an envelope product, wherein the cushioning product may be substantially stronger, yet, for example, thinner for better space utilization.

[0126] In preferred embodiments, an expanded paper cushioning product is provided employing an improved slit arrangement, not feasible with expanded paper products with prior slits, in which a compacted slit pattern is included with, for example, reduced slit lengths and reduced row spacing, along with the use of a new extensible paper.

[0128] According to some embodiments of the invention, a new groove pattern can be created that provides more cells per square meter and achieves greater crush resistance and resilience for cushioning. For example, preferred embodiments offer a substantial advantage for wrapping packaged items within a container (e.g., its use as cushioning wrap) or as padding for an envelope (including, in some illustrative preferred embodiments of envelopes, where the envelope includes at least one inner or outer layer of serrated paper).

[0130] In some preferred embodiments, the slit paper pattern advantageously features slits in the range of 0.76 to 1.14 centimeters (i.e., in the longitudinal dimension of the slits) and row spacing in the range of 0.286 to 0.428 centimeters (i.e., the distance between adjacent rows of slits). Preferably, these embodiments are made of extensible paper.

[0132] In some preferred embodiments, the slit paper has slits whose width is 1.14 cm plus 5%, minus 33% (i.e., here, the slit width refers to the longitudinal dimension of the slits). More preferably, again, these embodiments are also made of extensible paper.

[0134] In some preferred embodiments, the slit pattern advantageously produces an expandable slit paper with a number of legs per square meter at least 20% greater than that of slit paper with slit (cut) widths of 1.27 cm.

[0136] In some preferred embodiments, an expanded slit paper cushioning product of the present invention has a number of legs per square meter at least 15% greater than that of slit paper with slit (cut) widths of 1.27 cm. In some preferred embodiments, an expanded slit paper cushioning product of the present invention has a number of legs per square meter that is in the range of 20% to 50% greater than that of slit paper having slit (cut) widths of 1.27 cm.

[0138] With the present invention, expanded slit sheets with considerably improved damping characteristics can be created. In some embodiments of the present invention, the improvement in damping characteristics can be achieved by means of one or more, or all of the following elements:

[0140] a) In preferred embodiments, the use of an extensible paper allows for an "easy-opening" structure, which facilitates the creation of smaller cells, advantageously leading to a higher cell density and thus better damping characteristics.

[0141] b) In some preferred embodiments, the use of an extensible paper makes it possible to achieve a novel "alternating row expansion pattern" which has substantially improved damping characteristics compared to previous expansion patterns (see the discussion of the novel alternating row expansion pattern below in this document).

[0143] Furthermore, with the present invention, novel and previously unfeasible damping products can be created, such as:

[0145] a) In some preferred embodiments, a new envelope structure can be achieved with significant advantages over existing envelope structures. For example, the present invention allows for a substantially thinner expanded slit sheet with cushioning (e.g., with substantially smaller row spacing) and also provides substantial cushioning with a single layer or only a few layers. Consequently, an envelope with a much narrower width, and even with only a single layer of cushioning, can be achieved. Furthermore, the envelope can be manufactured from lighter paper, resulting in a product that is easier to use (e.g., less rigid) and lighter (e.g., with reduced shipping costs). It is worth noting that the lower weight of the product, along with the narrower width, translates into reduced shipping costs.

[0146] b) In some preferred embodiments, a novel damping envelope can be achieved that offers significant advantages over existing damping envelopes, such as, for example, enhanced damping characteristics, allowing, for example, a reduction in the number of damping layers required in some applications, a reduction in the amount of damping required, and other advantages and benefits as described herein.

[0148] Extensible paper used in preferred embodiments

[0150] In some more preferred embodiments, extensible papers are used as described in U.S. Patent No. 10,669,086 mentioned above. For this purpose, the following paragraphs (quoted in quotation marks) from patent '086 are cited after this section, detailing extensible papers according to some preferred embodiments that may be used in preferred embodiments of the present invention.

[0152] "For the purposes of the present invention, the term 'extensible', applied to sheets of paper, means a sheet of paper that can be stretched in the longitudinal direction by applying a force in that direction. Illustrative extendable leaves are described in U.S. Patent No. 3,908,071, U.S. Patent Application No. 14/901,977 (U.S. Patent No. 9,945,077), International Application No. WO 1984002936, U.S. Publications No. 2002/0060034, 2007/0240841 (US 7,918,966), and U.S. Patents Nos. 3,104,197, 3,220,116, 3,266,972, 3,269,393, 3,908,071, 6,024,832, 6,458,447, and 6,712,930. It should be understood that the stretch of an extensible paper must be measured on a sheet of paper without a crease. As described in U.S. Patent 3,266,972, the test and characterization procedures employed to measure elongation (extensibility) properties may meet the TAPPI standard, elongation test T457. Furthermore, as described in U.S. Patent 3,266,972, the term "extensible papers" refers to a paper with an elongation that can increase in the machine direction compared to standard non-extensible Kraft paper.

[0154] In some preferred embodiments, stretchable paper can be produced by varying the accumulation of paper fibers, essentially slowing the paper feeding process during drying to trap additional fibers that make the paper appear to have rows of microscopic paper, which would be visible when pleated. The difference is that the microscopic rows of stretchable paper adhere to each other through the use of binders and other types of adhesives along with the drying process. Reference is made to U.S. Patent Application No. 2007/0240841 (US 7,918,966), the objective of which is to create a non-curling stretchable paper that does not readily peel off. Furthermore, the surface of the stretchable paper remains quite flat.

[0156] "In preferred embodiments of the present invention, the extensible paper employed exhibits low extensibility properties compared to other types of extensible papers. In this respect, an optimal extensible paper allows a smooth transition from an unexpanded to an expanded slit sheet by providing a small stretch at the beginning of the expansion of the extensible slit sheet paper material."

[0158] “In some exemplary constructions, during the expansion of a slit sheet, the force required to initiate expansion is substantially greater than the force required to continue expansion. For example, once the paper begins to bend at the slits, expansion continues more readily as bending continues at the slits. The force required to continue the expansion of the slit sheet during this continued bending is dramatically reduced beyond the initial expansion described above. In some preferred embodiments, the extensible slit sheet paper substantially reduces the force required to initiate expansion. On the other hand, in some preferred embodiments, during the aforementioned continuous expansion, the extensible paper does not stretch substantially simultaneously with the expansion process of the slit sheet; otherwise, the expanded sheet might not optimally become a cushioning wrap.”

[0160] "It should be noted that, in this application, all theories relating to the operation of the invention are provided to facilitate an understanding of the concepts of the invention, and not by way of limitation. The extensible paper, as designed, stretches as part of an increase in paper strength. In some embodiments, the operation of the invention implies that the extensible slit-sheet paper substantially utilizes the extensible property to facilitate the rotation of the cells into the stretched form and to resist tearing of the slit-sheet during the expansion step. This means that, at the initial point where the cell rotates (i.e., initiating a rotation between legs 38a and 38b on each side of the slit and ground 20), the extensible slit-sheet paper is substantially enhanced by the ability of the extensible paper to stretch." Therefore, in some embodiments, the operation of the invention implies that the properties of the extensible papers are substantially utilized at this initial point and substantially terminate as soon as the cell begins to rotate into its three-dimensional shape (i.e., after this initial point, the dependence on the extensible nature of the paper becomes less substantial or even nonexistent). After this initial point, the properties of the slit pattern, regardless of the type of paper, open more readily to the point of forming a hexagon. Consequently, in some embodiments, the extensible property substantially comes into play merely at the initial moment of expansion. In some other embodiments, while the extensible characteristics of the paper come into play more substantially at this initial point of rotation, these extensible characteristics may have some effect during further expansion of the paper, whereby the initial point of expansion may be substantially facilitated due to the extensibility, and further expansion may also be facilitated, at least to some extent, due to the extensibility.

[0161] "In some of the preferred embodiments, the preferred extensible papers that may be employed include extensible papers whose purpose is to provide the type of stretch found for use in multi-wall bags for heavy articles such as cement, seeds, and the like. U.S. Patent Publication No. 2016/0355985 (U.S. Application No. 14/901,997) and U.S. Patent Nos. 3,104,197 and 3,266,972 describe the manufacture and properties of this type of extensible paper. Further details can be found in 'Understanding Sheet Extensibility', R.S. Seth, Pulp & Paper Canada T31, 106:2 (2005) III, pages 33-40 (T31-T38)."

[0163] "The prior expanded slit sheet technique (see, for example, U.S. Patent Nos. 5,538,778, 5,667,871, 5,688,578, and 5,782,735) focused on the paper's strength to inhibit tearing during the expansion process, and Kraft paper was satisfactory because the required strength matched the thickness required to manufacture a satisfactory wrapping product. The increased strength of an expandable sheet does not contribute to or increase the value/performance of the material's expansion in the slit sheet. The present inventor has now discovered that an expandable slit sheet can be substantially improved by using an expandable sheet." In preferred embodiments, this use of extensible slit sheet paper advantageously provides a reduction in the force required to open the slit sheet and thus provides a faster and easier expansion process for the user of the expanded slit sheet. The unexpected benefit resulting from the reduced force at the beginning of slit sheet expansion provides an unexpected improvement to the slit sheet packaging product and makes the use of extensible paper highly unique. It is noteworthy that prior expanded slit sheet paper persisted and was widely used in the market for decades without the present invention or the potential advantages arising from it being considered.

[0165] "As stated in the present application, the present inventor has discovered that the force required to expand an expandable slit sheet paper is much greater than the force required to expand an extensible slit sheet paper. For example, a 22.68-kilogram expandable slit Kraft paper sheet, 38.1 centimeters wide before expansion, requires approximately 1.8 to 2.7 kilograms or 0.18 kilograms per centimeter, whereas the force required to expand an extensible slit sheet of the same basis weight is 0.068 to 0.1 kilograms per centimeter. This is a marked difference between the papers. Kraft paper has the strength to provide an acceptable expandable slit sheet." However, unexpectedly, the extensible slit sheet imparts an ease of expansion that greatly reduces the force required to expand the slit sheet, not based on the primary purpose of extensible paper, which is to increase its tensile strength, but rather on its stretchability. Since extensible paper is more expensive and Kraft paper was strong enough, it was previously unknown that extensible paper could be beneficial for manufacturing cut-sheet paper of the types found, for example, in U.S. Patent Nos. 5,538,778, 5,667,871, 5,688,578, and 5,782,735 and U.S. Non-Provisional Application No. 15/428,144. For instance, it was not appreciated that an extensible slit sheet could provide equivalent strength to thin, lightweight papers that previously had no applicability as a wrapping product. Lightweight Kraft paper tears more easily than heavier Kraft paper. It has now been discovered that extensible paper allows the use of lighter, expanded slit-sheet papers, which also advantageously provide the softer cushioning required by fragile items when a slit-sheet is expanded, in contrast to the stiffer cushioning provided by heavier, expanded slit-sheet papers.

[0167] “Reference is made in particular to the graph in Table 1 on page 5 of U.S. Patent Publication No. 2016/0355985 (now U.S. Patent No. 9,945,077) as if recited in its entirety, which describes the strength of paper as a function of certain manufacturing techniques. Within the graph is a column describing the elongation at the point of breaking of the paper (or fiber tearing) separated into two subcolumns for the machine direction (MD) and the cross direction (CD), also known as the transverse direction. The percentage of elongation in Table 1 ranges from 5.3% to 7.1% in the cross direction (CD) and from 3.3% to 10.6% in the machine direction (MD).”

[0169] "Also referenced is U.S. patent 3,266,972 in Table III of column 5, which refers to elongation in the percentage range of 3.7% to 4.6% in the CD or transverse direction and 9.7% to 11.1% in the machine direction."

[0171] "In both '985 and '972, the variations are based on the manufacturing process that emphasizes tensile strength and stretch in the transverse or machine direction, respectively."

[0173] "The present inventor has discovered that, for expanding an extensible slit-sheet paper for use as packaging wrap and/or void filler, machine-directed extensibility ranging from 1% to 9% provides adequate extensibility, preferably from 1% to 6%, and most preferably from 1% to 4%. Lower extensibility coincides with lower paper costs per square foot. As stated above, it is understood that extensibility is measured on unslitted paper."

[0175] "In some alternative embodiments, the extensibility intervals in the machine direction of the extensible slit sheet paper may have intervals of:

[0176] a) from 1.5% to 9%, or more preferably from 1.5% to 6%, or even more preferably from 1.5% to 4%; or b) from 2% to 9%, or more preferably from 2% to 6%, or even more preferably from 2% to 4%; or c) from 3% to 9%, or more preferably from 3% to 6%, or even more preferably from 3% to 4%. "For expanding slit-sheet paper for use as packaging wrap or void filler, cross-directional extensibility ranges of 1% to 5% have been found to provide adequate extensibility, 1% to 4% being preferable, and 1% to 3% being the most preferred."

[0177] "In some alternative embodiments, the cross extensibility ranges of the extensible slit sheet paper may be: a) from 1.5% to 5%, or more preferably from 1.5% to 4%, or even more preferably from 1.5% to 3%; or b) from 2% to 5%, or more preferably from 2% to 4%, or even more preferably from 2% to 3%.

[0178] "In combination with the extensible paper, a smaller, lighter, and recyclable version of an expander can be used (for example, made entirely or almost entirely from recyclable cardboard in some illustrative embodiments). This expands the market to customers who use a very small amount of wrapping compared to the industrial market. It also eliminates the need for an expensive expansion device to expand the slitting paper. Furthermore, it improves ease of use for the packer by reducing tearing during the wrapping process, which occurs when tension is not properly set. This happens as the roll becomes smaller and lighter with continued use. As the expanded slitting sheet roll becomes lighter, the required tension increases. Therefore, a variable tensioning method is necessary. With the use of the extensible paper, the required tension decreases significantly, and the paper's strength increases." Both methods benefit the wrapper by making the required tension much less precise, to the point where a single tension setting can be used with little or no adjustment. If the tension is set higher than necessary, the increased strength of the stretch film prevents the product from tearing, thus making it easier for the wrapper to handle. Therefore, the wrapper can make fewer adjustments as the slit sheet roll gets smaller.

[0179] "The reduction in the force required to expand slit paper allows for the creation of a new product using lighter papers. In the past, expanded slit paper was primarily used as a wrapping product, with its use as a void filler being limited in certain circumstances because void fillers are typically the cheapest, i.e., the lowest-cost of all packaging products. The increased strength of the expandable sheet allows for the use of a thinner, lighter slit paper sheet as a void filler. If the expanded slit sheet is not used as wrapping, then a thicker paper of 0.013 cm, 22.68 kilograms per 914.4 square meters and above is not required, and a lighter paper of 0.0076 to 0.0114 cm in thickness and 13.61 to 18.14 kilograms per 914.4 square meters can be used as a void filler." It can also be used to provide cushioning that other paper gap-filling products have been unable to provide. It has been found that, although extensible paper is priced 10% higher, the use of thinner paper provides a much greater surface area per ton and more than offsets the higher cost of extensible paper compared to Kraft paper.

[0180] "Detailed descriptions of the technologies employed in the present invention cited in the disclosures" "The following are citations from Clupak's paper patent (U.S. Patent No. 9,945,077):" "Example 1:

[0181] High-strength Clupak paper with a basis weight of 84.9 g/m2 was manufactured using a void former papermaking machine equipped with a Clupak system, at a manufacturing speed of 480 m/min and using, as material, 100% unbleached softwood Kraft pulp, beaten to a high concentration of 28%. The Clupak demolding was adjusted to -4.5%.

[0182] «Example 2:

[0183] The high-strength Clupak paper was manufactured in the same way as in Example 1, except that the paper had a basis weight of 76.1 g/m2 and the Clupak demolding was adjusted to -6.0%.

[0184] «Example 3:

[0185] The high-strength Clupak paper was manufactured in the same way as in Example 1, except that the paper had a basis weight of 73.4 g/m2 and the Clupak demolding was adjusted to -4.0%.

[0186] «Example 4:

[0187] The high-strength Clupak paper was manufactured in the same manner as in Example 1, except that the paper had a basis weight of 85.0 g/m2 and the Clupak draft was adjusted to "up to -4.0%, and the pulp mixture consisted of 90% unbleached softwood Kraft pulp and 10% unbleached hardwood Kraft pulp."

[0188] «Comparative example 1:

[0189] The high-strength Clupak paper was manufactured in the same way as in Example 1, except that the paper had a basis weight of 71.9 g/m2 and the demolding in the Clupak was adjusted to -10.0%.

[0190] «Comparative example 2:

[0191] The high-strength Clupak paper was manufactured in the same way as in Example 1, except that the paper had a basis weight of 85.4 g/m2 and the draft in the Clupak was adjusted to -1.0%.

[0192] «Comparative example 3:

[0193] The high-strength Kraft paper was manufactured in the same way as in Example 1, except that the paper had a basis weight of 76.0 g/m2 and the Clupak process was not performed.

[0194]

[0197]

[0200]  Evaluation methods:

[0202] (Traction energy absorption index measurement)

[0204] Measured according to the method specified in JIS P8113: 2006.

[0205] (Measurement of elongation at break)

[0207] Measured according to the method specified in JIS P8113: 2006.

[0208] (Tear index measurement)

[0210] Measured according to the method specified in JIS P8116: 2000.

[0211] (Burst Index Measurement)

[0213] Measured according to the method specified in JIS P8112: 2008.

[0214] (Tensile stiffness index measurement)

[0216] Measured according to the method specified in ISO/DIS 1924-3.

[0217] (Measurement of freedom after disintegration)

[0219] Measured according to the method specified in JIS P8220: 1998 and JIS P8121: 1995.

[0221] "By observing the properties of the Clupak papers of Examples 1 to 4 and Comparative Examples 1 and 2, as well as those of the Kraft paper of Comparative Example 3, as shown in Table 1, the Clupak papers described in Examples 1 to 4 exhibit a good balance between various strengths and elongation, and exhibit excellent overall strength; on the other hand, the Clupak papers described in Comparative Examples 1 and 2 and the Kraft paper described in Comparative Example 3 exhibit a poor balance between various strengths and elongation, so it cannot be stated that they have excellent overall strength.

[0222] «The following are quotations from «Understanding Sheet Extensibility», R.S. Seth, (Pulp and Paper Research Institute of Canada, 3800 Wesbrook Mall, Vancouver, BC, Canada V6S 2L9) Pulp & Paper Canada T31, 106:2 (2005) III, pages 33-40 (T31-T38):

[0223] Tensile strength and extensibility, or stretch, are two important failure properties of paper. They are defined by the endpoint of the sheet's load-elongation curve (Fig. 1). Individually and together, they are important for many product performance properties. For example, TEA, the tensile energy absorbed by the sheet before failure, is proportional to the area under the load-elongation curve. Therefore, it depends on both the tensile strength and extensibility of the sheet. High TEA is desirable in sack papers [1]. The burst strength of paper has been shown to be proportional to the product of tensile force and the square root of the stretch [2]. The fracture toughness of paper has been found to depend strongly on the tensile force and the stretch of the paper [3, 4]. Sheet stretch has also been considered important for the paper's runnability at the dry end of the paper machine, such as in the printing room [5-8]. High-stretch papers also appear to have somewhat higher tear strength [9] and folding strength; they have also been found to be more dimensionally unstable [10]. The factors controlling the tensile strength of the control sheet are fairly well understood [4]. Tensile strength is high if the fibers are strong, long, fine, and thin-walled. The fibers must be conformable and have high fiber-fiber bond strength. The tensile strength of the sheet is also high if the fibers are straight, free from deformation, and the sheets are well-formed. Otherwise, the stress is distributed unevenly when the sheet is deformed, leading to premature breakage.

[0225] "This report addresses the factors that control leaf stretch."

[0227] «Factors that control leaf stretching:

[0229] A sample subjected to a tensile load extends more the longer it is. Therefore, extensibility, or stretching or deformation at the moment of breakage, as a property of the material, is expressed as a percentage of the original length of the sample (Fig. 1).

[0231] «Function of the union:

[0233] Regardless of how fiber bonding is increased (by wet pressing, beating, refining, or additives), sheet stretch of a paper pulp generally increases with greater fiber bonding. This is observed for almost all paper production fibers—chemical, mechanical, wood, non-wood, or recycled. The reasons are as follows. Fibers have a certain "stretch potential." However, this potential is only realized in paper when the fibers form a bonded network. If the bonding is weak, the network fails before the stretch potential is realized; sheet stretch is low. As bonding in the network increases, the fiber stretch potential is realized to a greater extent, and sheet stretch increases. Since increased fiber bonding also increases tensile strength, an increase in stretch with tensile strength is frequently observed for hand-pressed sheets (Figure 2). The stronger the sheet, the more the fiber stretch potential is utilized. Due to this relationship between tensile strength and elongation, factors such as basis weight or sheet formation, which tend to affect tensile strength, also affect sheet elongation [11]. A comparison of the elongation values of paper sheets at similar tensile strengths provides a meaningful comparison of the elongation potential of various materials.

[0234] «The following are quotations from the extensible paper patent of Trani et al. (U.S. Patent No. 7,918,966): "Extensible paper is a known paper that, due to a special treatment during its production, exhibits considerable extensibility both longitudinally (i.e., in the direction of its advance along the production line) and transversely (i.e., perpendicular to the former). This treatment essentially consists of passing the unformed paper web, which has a moisture content of approximately 35%–45%, between two rolls rotating at different speeds. One of these rolls, usually the lower roll, is made of rubber and rotates at a lower speed, while the upper roll is made of steel and has a continuous spiral groove on its cylindrical surface. The different nature of the material and the different speeds of the two rolls result in a kind of longitudinal accumulation of the paper-forming material, preparing it for longitudinal extensibility, in an amount that can reach 15–20%. At the same time, the spiral groove serves a dual purpose: On one hand, it causes a kind of transverse accumulation of the paper material to prepare it for transverse extensibility, by an amount that can reach 10-15%. On the other hand, the spiral groove helps maintain the longitudinal feed of the processed paper web along the machine.

[0235] "The following are quotations from the extensible paper strip patent of Cabell et al. (United States patent no. 6,458,447):"

[0237] «Traction test and percentage of stretch:

[0239] The tensile test is used to measure strength versus percentage of elongation. The tests are performed on a Thwing Albert Intellect II-STD, model no. 1451-24PGB, available from Thwing-Albert Co. of Philadelphia, Pennsylvania.

[0240] "The samples used for this test measure 2.54 cm wide x 15.24 cm long, with the longitudinal axis of the sample cut parallel to the direction of maximum extensibility of the sample. The sample must be cut with a sharp Exacto blade or a cutting device suitably sharpened to cut an accurate sample 2.54 cm wide. (If there is more than one direction of extensibility of the material, the samples must be taken parallel to the representative direction of elongation.) The sample must be cut so as to represent an area representative of the symmetry of the overall pattern of the deformed region. There will be cases (due to variations in the size of the deformed part or the relative geometries of regions 1 and 2) where it will be necessary to cut samples larger or smaller than suggested herein." In this case, it is very important to note (along with the data presented) the sample size, the area of the deformed region from which it was taken, and preferably include a diagram of the representative area used for the sample. Three samples of a given material are tested.

[0241] "The following are quotations from the extensible paper patent of Cramer et al. (United States patent no. 3,266,972):"

[0243] «Test and characterization procedures:

[0245] The test and characterization procedures employed to measure various properties described in this document are listed in Table I below. Unless otherwise indicated, code numbers denote standard TAPPI tests.

[0246] «Elongation T457:

[0248] The expression "extensible papers" refers to a paper with greater elongation (generally a minimum of about 6%) in the machine direction.

[0250] In tests IA and IB of this example, rosin resin (0.3% by weight, based on the weight of the pulp) is added to the beater, and the pH is adjusted to 4.5 with alum. The broth, which has a consistency of 3.6%, is dropped into the beater vat and then pumped to the second vat, passed through a Jordan, and continuously diluted with "white water" in the Fourdrinier inlet box to a consistency of 0.3%. The properties measured on the various papers are presented in Table III. Each paper has a basis weight of between 22.41 and 22.81 kilograms per ream.

[0251] TABLE III:

[0254]

[0257] "The following are quotations from the multilayer paper material patent of Trani et al. (United States patent no. 8,518,522):"

[0258] These and other objectives, which are evident from the following description, are achieved, according to the invention, by means of a multilayer paper material comprising at least a first sheet of three-dimensional structure with reliefs of maximum sizes smaller than the width of the original sheet. These reliefs are obtained by localized stretching of said first sheet, which has an original degree of extensibility of not less than 5% in all directions, and at least a second sheet of paper material coupled to said first sheet of structure, which defines empty spaces with the reliefs thereof.

[0260] "As can be seen in the figures, in the embodiment shown in figure 1, the multilayer material of the invention consists of two layers 2 and 4 of paper with an extensibility of not less than 5%, both in the longitudinal and transverse directions, and preferably not less than 15%."

[0261] «The following are quotations from the application for extensible paper material by Trani et al. (United States application no.

[0262] 22007/0240841):»

[0263] "Extensible paper is a type of paper that, due to a special treatment during its production, exhibits considerable extensibility both longitudinally (i.e., in the direction of its advance along the production line) and transversely (i.e., perpendicular to the former). This treatment essentially consists of passing the unformed paper web, which has a moisture content of around 35%/45%, between two rolls rotating at different speeds. One of these rolls, usually the lower roll, is made of rubber and rotates at a lower speed, while the upper roll is made of steel and has a continuous spiral groove on its cylindrical surface. The different nature of the material and the different speeds of the two rolls result in a kind of accumulation of the paper-forming material, preparing it for longitudinal extensibility by an amount that can reach 15-20%." At the same time, the spiral groove serves a dual purpose: on the one hand, it causes a kind of transverse accumulation of the paper-forming material to prepare it for transverse extensibility

[0265] in an amount that can reach 10-15%. On the other hand, the spiral groove helps to maintain the longitudinal advance of the processed paper web along the machine.

[0267] Further details relating to extensible papers that can be used in some preferred embodiments are also cited in patent '086, as follows.

[0269] "The following is a direct quotation from the paragraph in column 1, lines 4-19, of U.S. Patent No. 3,908,071: 'The extensible (compacted) paper produced, for example, according to the apparatus and process disclosed in U.S. Patent No. 2,624,245 has certain advantages and well-recognized commercial uses. This paper, while partially moistened, is subjected to compressive compaction in the direction of web movement (machine direction or MD) between a line of pressure, thereby compacting and bonding the fibers to produce inherent elasticity without creping. The compacted paper has improved tensile energy absorption (TEA) characteristics, which are highly desirable for end uses such as the manufacture of paper bags.'" Furthermore, the abstract of U.S. Patent No. 6,024,832 is quoted verbatim below: “A method for producing extensible paper, comprising the following steps: introducing a mixture of vegetable fibers into a mixer, mixing the mixture with water in the mixer, beating the fibers to obtain a pulp, transferring the beaten pulp to a flow hopper, feeding the beaten pulp from the flow hopper to a paper web forming fabric with the consequent reduction of the water percentage by gravity and vacuum, pressing the web, with the consequent further reduction of its water content, initially drying the paper web to a practically constant moisture content of between 15% and 65%, compacting, finally drying to a moisture content of between 15% and 4%, preferably between 10% and 8%, and brightening. The beating step is performed by rubbing the fibers in a multi-stage unit to obtain a pulp with a degree of beating of at least 30°C.” SR, the compaction stage is carried out between at least a pair of rollers, one of which is made of hard material with circumferential ribs and operates at a higher speed, and the other is made of soft material with a smooth surface and operates at a lower speed. Furthermore, the second paragraph of the background section of U.S. Patent No. 9,945,077 is quoted verbatim below: “On the other hand, Clupak refers to equipment that inserts a paper web between a roll and an endless rubber blanket to compress it with a pressure bar and the rubber blanket. At the same time, the previously stretched blanket contracts, causing the paper web to also contract and thus increase its elongation at break. This equipment is used to provide greater elongation at break to kraft paper used in heavy packaging applications, as mentioned above.” Furthermore, the following is a verbatim quote from the paragraph in column 2, lines 41-56, of U.S. Patent No. 3,104,197: “The use of rubber or a rubbery material in conjunction with a hard surface in the manner described is known in the treatment of paper and fabrics, but only in a general way, and the present invention includes the use of rubber that is considerably softer and more elastic than that previously used. Also of great importance in the production of extensible paper by creping it in this manner is the difference in the drive speeds of the rollers. If the appropriate combination of hard and soft surfaces is provided, a semi-dry paper web passing over the contact line of the rollers will be drawn by the contracting rubber in the opposite direction to the web, toward the contact line and onto the surface of the hard roller. This creates a uniformly compressed crepe on the paper web, giving it toughness, flexibility, and extensibility.”

[0270] "The following are direct quotations from paragraphs [0003] and [0028] of U.S. Patent Publication No. 2016/0355985 (1) "[0003] On the other hand, Clupak refers to equipment that inserts a paper web between a roll and an endless rubber blanket to compress it with a pressure bar and the rubber blanket, while at the same time the previously stretched blanket shrinks to cause the paper web to also shrink and thereby increase its elongation at break. This equipment is used to provide greater elongation at break to kraft paper used in heavy packaging applications, as mentioned above;" and "[0028] The manufacturing method used by this Clupak system is such that a paper web is inserted between a roll and an endless rubber blanket to compress the paper web with a pressure bar and the rubber blanket, while at the same time the previously stretched blanket contracts to cause the paper web to also contract and thus increase its elongation at break. The Clupak system allows the elongation at break of the kraft paper to be adjusted in the longitudinal direction according to the ratio between the manufacturing speed on the input side of the Clupak system and the manufacturing speed on the output side of the Clupak system, and also according to the pressurization force applied by the pressure bar.

[0272] In some embodiments, the extensible paper employed may have one or more of the following characteristics, as set out in patent '086.

[0274] Example 1: An extensible slit sheet paper cushioning product, comprising: a roll of paper with a slit pattern including a plurality of transverse slits forming a plurality of open cells when expanded in the machine direction. Said roll resists the pull of a piece of paper in the machine direction to allow its expansion in said direction. The paper is formed from a paper that is extensible in both the machine and transverse directions before obtaining said slit pattern. Said extensible paper has an extensibility range of 3 to 20% in the machine direction before obtaining said slit pattern.

[0276] Example 2: Slit-sheet paper cushioning product of Example 1, wherein said extensibility range is not less than 5% in both the machine and transverse directions.

[0278] Example 3: The slit sheet paper cushioning product of Example 1, wherein said extensibility range is 3-15% in the machine direction.

[0280] Example 4: The slit-sheet paper damping product of Example 1, wherein said slit-sheet is configured such that expansion is effected by applying an expansion force of 0.068 to 0.099 kilograms per centimeter to form said open cells.

[0282] Example 5: The slit-sheet paper damping product of Example 2, wherein said slit-sheet is configured such that expansion is effected by applying an expansion force of 0.068 to 0.099 kilograms per centimeter to form said open cells.

[0284] Example 6: The extensible slit-sheet paper cushioning product of Example 5, wherein said slit-sheet paper has a weight, before expansion, of approximately 13.6 to 22.67 kilograms per 914.4 square meters.

[0285] Example 7: The extensible slit-sheet paper cushioning product of Example 1, wherein said slit-sheet paper has a weight, before expansion, of approximately 13.6 to 22.67 kilograms per 914.4 square meters.

[0287] Example 8: A packaging comprising: a wrapped object, said object being wrapped in at least two layers of an expanded slit-leaf paper wrapper with interlocking hexagonal cells, said slit-leaf paper having a slit pattern including a plurality of slits extending in the transverse direction and forming a plurality of hexagonal cells when expanded in the machine direction and expanding upon application of an expansion force and being wrapped to form said at least two layers of expanded slit-leaf paper wrapper with interlocking hexagonal cells, said slit-leaf paper being formed from a paper that is extensible in the machine direction and in the transverse direction before providing said slit pattern, said extensible paper having an extensibility range of 3 to 20% in the machine direction before providing said slit pattern.

[0289] Example 9: The packaging of example 8, wherein said extensibility range is not less than 5% in both the machine direction and the transverse direction.

[0291] Example 10: The packaging of claim 8, wherein said extensibility range is from 3 to 15% in the machine direction.

[0293] Example 11: The packaging of example 8, wherein said slit sheet is configured in such a way that expansion is effected by applying an expansion force of 0.068 to 0.099 kilograms per centimeter to form said hexagonal cells.

[0295] Example 12: The packaging of example 11, wherein said slit sheet paper has a weight, before expansion, of approximately 13.6 to 22.67 kilograms per 914.4 square meters.

[0297] Example 13: The shipping package of example 8, wherein said slit sheet paper has a weight, before expansion, of approximately 13.6 to 22.67 kilograms per 914.4 square meters.

[0299] Example 14: A method for expanding and wrapping a slit-sheet paper that, when expanded and wrapped, forms two or more layers of interlocking hexagonal cells, comprising the following steps: providing a slit-sheet paper with a slit pattern that includes a plurality of transverse slits forming several hexagonal cells when expanded in the machine direction. The slit-sheet paper is formed from paper that is extensible in the machine direction and in the transverse direction before providing the slit pattern, with an extensibility range of 3 to 20% in the machine direction before providing the slit pattern; expanding the slit-sheet paper and wrapping the expanded slit-sheet paper to form adjacent layers that interlock, such that the expanded layers resist shrinkage and tearing.

[0301] Example 15: The method of example 14, wherein said extensible interval is not less than 5% in both the machine direction and the transverse direction.

[0303] Example 16: The method of example 14, wherein said extensible range is from 3 to 15% in the machine direction.

[0304] Example 17: The method of Example 14, wherein said expansion stage comprises applying an expansion force of 0.068 to 0.099 kilograms per centimeter to form said hexagonal cells.

[0306] Example 18: The method of example 17, wherein said cut sheet of paper has a weight, before expansion, of approximately 13.6 to 22.67 kilograms per 914.4 square meters.

[0308] Example 19: The method of example 14, wherein said cut sheet of paper has a weight, before expansion, of approximately 13.6 to 22.67 kilograms per 914.4 square meters.

[0310] Example 20: The method of Example 14, wherein the step of wrapping said slit-leaf paper to form said adjacent layers, comprises: wrapping the expanded slit-leaf paper around an object and forming said two or more layers of overlapping interlocking hexagonal cells around said object, said overlapping interlocking hexagonal cells being in direct contact substantially across the width of the layers.

[0311] Example 21: The method of Example 20, wherein said extensibility range is 3-15% in the machine direction and not less than 5% in the transverse direction.

[0313] Example 22: The method of Example 20, wherein said extensibility range is 3-9% in the machine direction and not less than 5% in the transverse direction.

[0314] Example 23: The method of Example 20, wherein said expansion stage comprises applying an expansion force of 0.068 to 0.099 kilograms per centimeter to form said hexagonal cells.

[0315] Example 24: The method of Example 21, wherein said expansion stage comprises applying an expansion force of 0.068 to 0.099 kilograms per centimeter to form said hexagonal cells.

[0316] Example 25: A method for protecting an object for shipment by wrapping and cushioning it with an expanded slit sheet material, comprising the steps of: a) providing a roll with a sheet of expandable sheet material wound around it, said sheet of expandable sheet material being a flexible, non-woven fibrous material and having a plurality of parallel, spaced rows of individual slits extending in the transverse direction, said flexible, non-woven fibrous material being a machine-stretchable paper and a transverse-stretchable paper before providing said slits, said stretchable paper having an extensibility range of 3 to 20% in the machine direction before providing said slits; b) expanding a length of said expandable sheet material unwound from the roll by applying an expansion force to form at least one expanded slit sheet material and a series of openings; c) wrapping said expanded slit sheet material around an object; and d) place the wrapped object in a package.

[0317] Example 26: The method of Example 25, wherein said extensibility range is 3-15% in the machine direction and not less than 5% in the transverse direction.

[0318] Example 27: The method of Example 25, wherein said extensibility range is 3-9% in the machine direction and not less than 5% in the transverse direction.

[0319] Example 28: The method of Example 25, wherein the expansion stage of a section of said expandable sheet material comprises applying an expansion force of 0.068 to 0.099 kilograms per centimeter.

[0320] Example 29: The method of Example 26, wherein the expansion stage of a section of said expandable sheet material comprises applying an expansion force of 0.068 to 0.099 kilograms per centimeter.

[0321] Example 30: The method of Example 25, wherein slit-extensible paper has a weight, before expansion, of approximately 13.6 to 22.67 kilograms per 914.4 square meters.

[0322] Example 31: The method of Example 28, wherein slit-extensible paper has a weight, before expansion, of approximately 13.6 to 22.67 kilograms per 914.4 square meters.

[0323] Example 32: The slit sheet paper damping product of Example 1, wherein said extensibility range is 3-11.1% in the machine direction.

[0324] Example 33: The packaging of example 8, wherein said extensibility range is 3-11.1% in the machine direction.

[0325] Example 34: The method of example 14, wherein said extensible interval is from 3 to 11.1% in the machine direction.

[0326] Example 35: The method of example 25, wherein said extensible interval is from 3 to 11.1% in the machine direction.

[0327] Example 36: The slit sheet paper cushioning product of Example 1, wherein said extensibility range is 3.3-10.6% in the machine direction.

[0328] Example 37: The packaging of example 8, wherein said extensibility range is 3.3-10.6% in the machine direction.

[0329] Example 38: The method of example 14, wherein said extensible range is from 3.3 to 10.6% in the machine direction.

[0330] Example 39: The method of example 25, wherein said extensible range is from 3.3 to 10.6% in the machine direction.

[0331] Example 40: The slit sheet paper cushioning product of Example 1, wherein said extensibility range is 9.7-11.1% in the machine direction.

[0332] Example 41: The shipping packaging of example 8, wherein said extensibility range is 9.7-11.1% in the machine direction.

[0333] Example 42: The method of example 14, wherein said extensible interval is from 9.7 to 11.1% in the machine direction.

[0335] Example 43: The method of example 25, wherein said extensible interval is from 9.7 to 11.1% in the machine direction.

[0337] Example 44: Extensible slit sheet paper cushioning product of Example 1, wherein said extensible paper is formed by a pretreatment of the slit pattern comprising inserting said paper between a roll and a pre-stretched endless blanket to compress it with a pressure bar and the blanket (or compressing it between two different surfaces (e.g., with different movements), such as between two different rollers).

[0339] Example 45: The packaging of Example 8, wherein said extensible paper is formed by a pretreatment to the slit pattern comprising inserting said paper between a roll and a pre-stretched endless blanket to compress it with a pressure bar and the blanket (or compressing it between two different surfaces (e.g., with different movements), such as between two different rollers).

[0341] Example 46: The method of Example 14, wherein said extensible paper is formed by a pretreatment to the slit pattern comprising inserting said paper between a roll and a previously stretched endless blanket to compress it with a pressure bar and the blanket (or compressing it between two different surfaces (e.g., with different movements), such as between two different rollers).

[0343] Example 47: The method of Example 25, wherein said extensible paper is formed by a pretreatment of the slits comprising inserting said paper between a roll and a previously stretched endless blanket to compress it with a pressure bar and the blanket (or compressing it between two different surfaces (e.g., with different movements), such as between two different rollers).

[0345] Example 48: The method of example 14, wherein the expansion stage includes a user manually expanding said slit sheet material.

[0347] Example 49: The method of Example 48, wherein the user manually expands said slit sheet material, which involves manually holding it and pulling and unwinding it from a roll against the resistance of the roll.

[0349] Example 50: The method of Example 25, wherein the user manually expands a section of said unrolled expandable sheet material, which involves manually grasping the expandable sheet material and pulling and unrolling it from the roll against the resistance of the roll.

[0351] Example 51: The extensible slit sheet paper of Example 1, wherein said extensible paper is a fiber-to-fiber bonded nonwoven fibrous material that resists tearing after an expansion of 3-15% in the machine direction, measured before providing the slit pattern.

[0353] Example 52: The packaging of Example 8, wherein said extensible paper is a fiber-to-fiber bonded nonwoven fibrous material that resists tearing after an expansion of 3-15% in the machine direction, measured before providing the slit pattern.

[0355] Example 53: The method of Example 14, wherein said extensible paper is a fiber-to-fiber nonwoven fibrous material that resists tearing after an expansion of 3-15% in the machine direction, measured before providing the slit pattern.

[0357] Example 54: The method of Example 25, wherein said fibrous nonwoven material comprises a fiber-to-fiber bond that resists tearing after an expansion of 3-15% in the machine direction, measured before providing the slits.

[0359] Example 55: The extensible slit-sheet paper cushioning product of Example 1, wherein the paper roll is wound on a cylindrical core and the length of the slit sheet extends from said roll.

[0360] Example 56: The extensible slit sheet paper damping product of Example 1, wherein the extensibility range is 5-15% in the transverse direction.

[0362] Example 57: The extensible slit-sheet paper damping product of Example 1, wherein the extensibility range is 7.1-15% in the transverse direction.

[0364] Example 58: An extensible slit sheet paper cushioning product, comprising: a roll of slit pattern paper including a plurality of transverse slits forming a plurality of open cells when expanded in the machine direction, said slit sheet paper being formed from paper that is extensible both in the machine and transverse directions before obtaining said slit pattern, said extensible paper having an extensibility range of 3 to 20% in the machine direction before obtaining said slit pattern.

[0365] Example 59: The extensible slit sheet paper cushioning product of Example 58 further includes a resistance that prevents the paper piece from being pulled along the machine direction to allow it to expand in that direction.

[0366] Example 60: The damping product of the extensible slit-leaf paper of Example 59, wherein the resistance is a roll of slit-leaf paper from which that length is extended.

[0367] Example 61: Slit-sheet paper cushioning product of Example 58, wherein said extensibility range is not less than 5% in both the machine and transverse directions.

[0368] Example 62: The slit-sheet paper cushioning product of Example 58, wherein said extensibility range is 3-15% in the machine direction.

[0369] Example 63: The slit-sheet paper damping product of Example 58, wherein said slit-sheet is configured such that expansion is effected by applying an expansion force of 0.068 to 0.099 kilograms per centimeter to form said open cells.

[0370] Example 64: The extensible slit-sheet paper cushioning product of Example 58, wherein said slit-sheet paper has a weight, before expansion, of approximately 13.6 to 22.67 kilograms per 914.4 square meters.

[0371] Example 65: The extensible slit sheet paper cushioning product of Example 58, wherein said extensible slit sheet paper cushioning product is a packaging.

[0372] Example 66: The extensible slit-sheet paper cushioning product of Example 65, wherein said slit-sheet paper is arranged to protect an object placed within said packaging.

[0373] Example 67: The expandable slit-sheet paper cushioning product of Example 66, wherein said slit-sheet paper is arranged to extend around an object placed within said packaging. Example 68: A method for using the expandable slit-sheet paper cushioning product of Example 66, comprising shipping the packaging with an object protected by said expandable paper inside the packaging. Example 69: The expandable slit-sheet paper cushioning product of Example 1, wherein said slit pattern is configured to form a plurality of hexagonal cells when expanded in the machine direction.

[0374] Example 70: The extensible slit-leaf paper damping product of Example 69, wherein said hexagonal cells are three-dimensional hexagonal cells with substantially rectangular ground parts situated at an inclined angle transverse to the original plane of the slit-leaf paper, and leg parts connecting the ground parts.

[0375] Example 71: The extensible slit sheet paper cushioning product of Example 58, wherein said slit pattern is configured to form a plurality of hexagonal cells when expanded in the machine direction.

[0376] Example 72: The extensible slit-leaf paper damping product of Example 71, wherein said hexagonal cells are three-dimensional hexagonal cells with substantially rectangular ground parts situated at an inclined angle transverse to the original plane of the slit-leaf paper, and leg parts connecting the ground parts.

[0377] Envelope products in some preferred embodiments

[0378] According to some preferred embodiments of the invention, a novel extensible slit sheet paper cushioning product, according to preferred embodiments of the present invention, can be used in the manufacture of envelopes. In some preferred embodiments, the envelopes can be of the type described in the applicant's pending U.S. application serial no. 16/531.017 (the '017' application), filed on May 6, 2020, and also filed as PCT/US2019/045027 (published on February 13, 2020 as WO2020/033275).

[0379] For illustrative purposes, Figures 8(A) and 8(B) correspond to Figures 1 and 7, respectively, of application '017. As shown in this exemplary embodiment, expanded slit sheet material is used in combination with an outer layer of embossed paper to produce a cushioned envelope with shock-absorbing properties. Although an outer embossed paper is shown, in some embodiments, the embossing may be eliminated.

[0380] As shown in Figure 8(A), this illustrative embodiment features a pad 100 composed of four layers, consisting of a first layer of embossed paper 104, two layers of expanded slit-leaf paper 102 and 103, and a fourth layer of embossed paper 101 on the top layer. To form the envelope, this composite is folded and sealed along the edges to form an envelope pouch. In preferred embodiments, this produces a fully recyclable paper pad, made primarily of recycled paper. To form the envelope 600 from the pad shown in Figure 8(A), the pad is first folded to create a pouch 704, as shown in Figure 8(B), and the sides 703 are then flattened and glued. Next, a double-sided adhesive strip 502 is affixed to a portion of the lip, as shown in Figure 8(B), along with a release liner 701, which is removed to expose the adhesive. By folding over the portion of the lip 702 that protrudes from the pouch 704, the lip portion 702 adheres to the front of the pouch to close and seal the envelope.

[0382] Although this example includes two inner sheets of expanded slit paper 102, 103, in some preferred embodiments, which employ the novel slit paper of the present invention, a single layer of expanded slit paper may be used. For example, layers 104 and 101 may, in some embodiments of the present invention, be located on opposite sides of a single layer of expanded slit paper. Furthermore, as indicated above, although Figure 8(A) shows layer 101 with relief, in some embodiments, layer 101 may be relief-free. Similarly, as indicated above, although Figure 8(A) shows layer 104 with relief, in some embodiments, layer 104 may be relief-free. Moreover, in some embodiments, both layers, 101 and 104, may be relief-free.

[0384] Embossed paper used in some preferred embodiments

[0386] According to some preferred embodiments of the invention, a novel extensible slit sheet paper cushioning product, according to preferred embodiments of the present invention, can be used in the manufacture of products (such as, for example, envelopes or other miscellaneous products) that include embossed paper. In some preferred embodiments, the products employing such embossed paper can be of the type described in the applicant's pending U.S. application, serial no. 16/870,195, filed on May 8, 2020, and also filed as PCT/US2020/32146, as well as in the aforementioned '017 application.

[0388] In preferred embodiments, the term "embossed" means raising or lowering a region of a sheet of paper. Preferably, embossing comprises raised or lowered regions of a sheet of paper that are raised or lowered by the application of a force that presses the paper into a relief shape, wherein the pressure causes the sheet of paper to deform into a shape that includes such raised or lowered regions. In some preferred embodiments, the sheet of paper is initially substantially flat and without the raised or lowered regions of embossing. It is subsequently pressed to deform it, including the raised or lowered regions. These raised or lowered regions, with respect to the original plane of the original flat sheet of paper, are referred to in the most preferred embodiments as "embossed" regions or "embossing." By way of example, in the most preferred embodiments, the reliefs are created by pressing an initial sheet (e.g., a flat or substantially flat sheet) between opposing pressure surfaces, such as, for example, (1) between die plates that move reciprocally against each other to press the surface of the flat sheet, wherein the die plates have a pattern of raised and recessed regions (e.g., male and female regions) that create cross pressure on the face of the flat sheet to cause the sheet to deform and form reliefs and/or (2) between two rollers wherein the rollers have a pattern of raised and recessed regions (e.g., male and female regions) that create cross pressure on the face of the flat sheet to cause the sheet to deform and form reliefs. In some embodiments, embossing may involve pressure applied by a single reciprocating die plate with a raised/reduced relief pattern pressing against a first paper surface, while the opposite side of the paper is pressed or supported by an elastic element (e.g., rubber) that flexibly receives the raised or depressed portions to create relief on the paper sheet. Similarly, in some embodiments, embossing may involve pressure applied by a single die plate with a raised/reduced relief pattern pressing against a first paper surface, while the opposite side of the paper is pressed or supported by an elastic element (e.g., rubber) or another surface element, such as a conveyor belt or other element, that flexibly receives the raised or depressed portions to create relief on the paper sheet.

[0390] In some preferred embodiments, the reliefs are formed following a repeating pattern along a sheet of paper transported from an initial roll. In some preferred embodiments, the reliefs define discrete shapes that are displaced from the original plane of the paper (e.g., raised or recessed) within separate regions along the face of the sheet. In some preferred embodiments, these discrete regions may have an irregular shape, while in others they may be circular, elliptical, oval, polygonal, triangular, square, pentagonal, hexagonal, octagonal, or other shapes. In the most preferred embodiments, the reliefs are hexagonal. In this case, the term "shape" of the reliefs, mentioned in the preceding paragraph, refers to the shape of the reliefs as viewed from below toward a face of the paper sheet. It should be understood that, viewed from a side view, these reliefs have a different shape.

[0391] Novel expansion pattern

[0393] For reference, Figure 4(A) shows a top plan view of a sample of expanded slit-sheet paper made from Kraft paper, which opens in a manner substantially similar to that shown in Figure 3(B), described above. In particular, this paper includes, in its unexpanded state, a row array similar to that shown in Figure 3(A) and, when expanded, adopts the expansion pattern shown in Figure 4(A). As shown in Figure 4(A), the expansion pattern includes the formation of substantially flat, angled, ground portions 20 that extend across the width of the expanded sheet, along with leg portions 21. Each ground portion has four respective leg portions 21 extending from it.

[0395] For further reference, Figure 4(B) shows a top view of the same expanded slit-sheet paper shown in Figure 4(A), taken at an angle to the plane of the expanded paper so that the expanded cells of the paper are viewed directly (i.e., taken at an angle substantially parallel to the angle of inclination of the ground portions 20). As shown, at this angle, the expansion pattern forms substantially hexagonal cells. For further reference, Figure 4(C) shows a top view of the same expanded slit-sheet paper shown in Figures 4(A) and 4(B), but taken at an angle to the plane of the expanded paper opposite to the angle shown in Figure 4(B), so that the cell openings are obscured from view by the broad sides of the ground portions 20 and the leg portions 21.

[0397] Included for further reference, Figure 4(D) shows a top view of the same expanded slit-sheet paper shown in Figures 4(A)–4(C), but taken at an angle to the plane of the expanded paper from a position below the plane of the paper near the bottom edge of Figure 4(D). This view helps demonstrate how the ground pieces 20 extend at a consistent angle, with the left edge of each ground piece in a lower position and the right edge of each ground piece in a higher position, so as to extend upward at a slope from the left to right sides of the ground piece as shown in Figure 4(D). As shown in Figure 4(D), this expansion pattern creates an array of open cell openings 26, each with a high side HS to the left of the open cell and a low side LS to the right of the open cell, as shown in Figure 4(D).

[0399] In some embodiments of the present invention employing a novel slit pattern as described herein, an expansion pattern similar to that shown in Figures 4(A)-4(D) may be used. For example, in some embodiments with shorter slit lengths, such as, for instance, some embodiments of Examples A to Example I in Table A below, the slit sheet paper may be configured to adopt an expansion pattern similar to that shown in Figures 4(A)-4(D), referred to herein as the "normal expansion pattern".

[0401] However, in some embodiments of the present invention, an expansion pattern similar to that shown in Figure 5(A) may be used. Figure 5(A) shows a novel expansion pattern according to some preferred embodiments of the present invention, referred to herein as the "alternating row expansion pattern." Although some preferred embodiments of the present invention will include this novel "alternating row expansion pattern," it is not necessary to use this type of expansion pattern in all embodiments of the invention.

[0402] Furthermore, although the alternating row expansion pattern may be employed in some preferred embodiments of the invention that include novel reduced-size slit patterns described herein, this alternating row expansion pattern provides a novel and advantageous inventive feature that can be implemented in the context of any desired slit size pattern, such as, for example, slit size patterns with slit lengths of 1.27 centimeters or even greater in some preferred embodiments.

[0404] It is worth noting that this type of alternating row expansion pattern can be achieved using extensible slit-sheet paper with sufficient extensibility. For this purpose, the extensibility is preferably adjusted to be sufficient in both the machine and cross directions to achieve this alternating row expansion pattern. For example, with slit-sheet paper 1.27 centimeters long, 0.476 meters of ground length (between slits within the same row), and a row spacing of 0.317 centimeters, this type of alternating row expansion pattern has been achieved using extensible paper with an extensibility of i) 22.35 in the machine direction and ii) 22.35 in the cross direction. In some examples, this expansion pattern can be achieved using extensible paper sheets of 13.6, 18.14, or 22.67 kilograms with this slit arrangement.

[0406] In other embodiments, with a slit-sheet paper 1.27 centimeters in length, an extensibility of at least approximately 6% in both the machine direction and the transverse direction can advantageously achieve such an alternate row expansion pattern.

[0408] In some preferred embodiments, this alternating row expansion pattern can be achieved with slit patterns employing extensible paper that is extensible in a machine direction by at least 5% and in a transverse direction by at least 5%, or, in some more preferred embodiments, that is extensible in a machine direction by at least 6% and in a transverse direction by at least 6%, or, in some more preferred embodiments, that is extensible in a machine direction by at least 7% and in a transverse direction by at least 7%, or, in some more preferred embodiments, that is extensible in a machine direction by at least 8% and in a transverse direction by at least 8%.

[0410] It is noteworthy that the present inventor discovered that this novel alternating row expansion pattern could be created by implementing extensible paper, even with the same original slit pattern of an unexpanded sheet. In particular, even when the same slit pattern arrangement is provided on an unexpanded paper (including slit lengths, spacing between slits in the same slit rows, and spacing between adjacent slit rows), the present inventor discovered that the expansion pattern could be adjusted to achieve an alternating row expansion pattern, for example, by modifying the paper to include extensible paper.

[0412] As illustrated in Figure 5(A), the alternating row expansion pattern includes alternating rows (rows R-a and rows R-b) with bottom cell openings a26 and top cell openings b26. In particular, as shown, the cell openings a26 in rows R-a are located at the bottom of the expanded sheet of paper (i.e., on the opposite or farther side from the viewpoint of Figure 5(A), or downward in page view), and the cell openings b26 in rows R-b are located at the top of the expanded sheet of paper (i.e., on the side near or close to the viewpoint of Figure 5(A)).

[0414] As also illustrated in Figure 5(A), the earth parts formed in the regions between the ends of the slits in the same row of slits are formed differently from the earth parts 20 of the embodiment described in relation to, for example, Figure 4(A). It is noteworthy that, instead of assuming an angle that extends uniformly upward or downward, like the earth parts 20 of Figure 4(A), the earth parts of Figure 5(A) include sections oriented upward and downward. That is, each earth part includes a section that extends upward and another that extends downward. Furthermore, each earth part of Figure 5(A) includes a folded or angled section, aligned between adjacent slits within the same row of slits, around which the angles of inclination between the two sections of the earth part change. For example, as shown in Figure 5(A), the ground parts in rows R-a include a first part 20a1 extending upward from an edge of an open cell a26 on a left side of the ground part to the folded or angled portion in the center of the ground part, and a second part 20a2 extending downward from the folded or angled portion in the center of the ground part to an edge of an open cell a26 on a right side of the ground part. As shown in Figure 5(A), all the ground parts within row R-a have a vertical configuration similar to that shown in the figure, in which the folded or angled portion in the center of the ground part forms a top vertex or ridge that is located at the highest point of the ground part toward the top face of the expanded sheet of paper (i.e., the one closest to the closed side from the viewpoint of Figure 5(A)).

[0416] Similarly, as also shown in Figure 5(A), all the ground parts within the R-b row have an opposite vertical configuration, as shown in the figure, in which a folded or angled portion in the center of the ground part forms a lower ridge that is at the lowest point of the ground part toward the underside of the expanded sheet of paper (i.e., the one furthest from the closed side from the viewpoint of Figure 5(A)). In particular, as shown in Figure 5(A), the support parts in the R-b rows include a first part 20b1 extending downward from the edge of an open cell b26 on the left side of the support part to the folded or angled portion in the center of the support part, and a second part 20b2 extending upward from the folded or angled portion in the center of the support part to the edge of an open cell b26 on the right side of the support part. As shown in Figure 5(A), all the ground parts within the R-b row have a similar downward and upward configuration as shown in the figure.

[0418] Furthermore, in the expansion pattern of Figure 4(A), the leg portions extending from a first side of the ground portion extend in different directions. In particular, this includes the first legs extending upward from the top edge of the ground portion toward a closed side of the expanded paper (e.g., toward the upper left corner of Figure 4(A)), and the second legs extending downward from that top edge of the ground portion toward a farther side of the expanded paper (e.g., toward the upper right corner of Figure 4(A)). This also includes the third legs extending upward from the bottom edge of the ground portion toward a closed side of the expanded paper (e.g., toward the lower left corner of Figure 4(A)), and the fourth legs extending downward from that bottom edge of the ground portion toward a farther side of the expanded paper (e.g., toward the lower right corner of Figure 4(A)).

[0420] However, unlike the embodiment shown in Figure 4(A), in the alternating row expansion pattern shown in Figure 5(A), the leg portions extending from a first side of the support portion extend in similar directions. In particular, the leg portions extend so as to create the alternating rows R-a and R-b, wherein these alternating rows R-a and R-b are located on opposite sides of the expanded slit sheet in the width direction of the sheet; that is, with the R-a rows being on a side far from the expanded slit sheet in the width direction, as seen in Figure 5(A), and with the R-b rows being on a side near the expanded slit sheet in the width direction of the sheet.

[0422] In particular, as shown in Figure 5(A), the legs include: a) first legs 21a extending from an upper edge of a ground part 20b2 downward to a ground part 20a1; b) second legs 20b extending from an upper edge of a ground part 20b1 downward to a ground part 20a2; c) third legs 21c extending from a lower edge of a ground part 20b2 downward to another ground part 20a1; and d) fourth legs 20d extending from a lower edge of a ground part 20b1 downward to another ground part 20a2.

[0424] The present inventor has also discovered that the present alternating row expansion pattern offers several substantial advantages and benefits over the expansion pattern shown in Figure 4(A). First, the alternating row expansion pattern offers significant aesthetic benefits and is more eye-catching and interesting. Second, the alternating row expansion pattern creates a visually more obstructive expansion pattern from various angles. Third, the alternating row expansion pattern creates an expansion pattern that improves damping and operating characteristics.

[0426] Whereas the open cells 26 of the example shown in Figure 4(A) create cells with a high side HS on the near side of the expanded paper and a low side LS on the opposite side (as shown in Figure 4(A)), the open cells a26 and b26 shown in Figure 5(A) create cells with both sides at similar heights (i.e., either on a high side, as in the case of cells b26, or on a low side, as in the case of cells a26). Among other things, the forces applied to the periphery of the open cells a26 and b26 are generally applied more evenly on opposite sides of the open cells, rather than being applied on only one side of the open cells 26 shown in Figure 4(A).

[0428] For further reference, Figures 6(A) to 6(C) provide an explanatory diagram demonstrating the formation of the alternating row expansion pattern according to preferred embodiments of the invention. First, Figure 6(A) shows an illustrative indentation pattern formed within a sheet of paper. In some embodiments, the indentation pattern is generally similar to that shown in Figure 3(A), described above. However, as described below, in the more preferred embodiments of the present invention, the indentation pattern features novel and advantageous dimensions, indentation ratios, and indentation patterns, as described below.

[0430] As shown in Figure 6(A), the slits include several rows that extend substantially horizontally across the page of the figure. Although only 7 slits S are shown (for illustrative purposes), it should be noted that the product includes rows of slits that extend the full length of the sheet of paper. As shown, the slits preferably have a common length SL (i.e., all slits preferably have the same length), a common spacing SS between the ends of the slits in the same row (i.e., all spacings between slits preferably have the same length), and a common spacing RS between adjacent rows (i.e., all spacings between rows preferably have the same distance). Furthermore, as also shown, the degree of overlap between slits in adjacent rows preferably includes equal spacings OL1 and OL2 (i.e., the slits in adjacent rows are preferably aligned symmetrically to create symmetrical cells when expanded).

[0432] Figure 6(B) shows the slit pattern of Figure 6(A) with regions of the paper before expansion highlighted for reference. For this purpose, regions A1, A2, B1, B2, C1, C2, D1, and D2 are shaded in the figure for ease of reference. However, it should be noted that, in this unexpanded state shown in Figure 6(B), these regions are all planar along the plane of the original unexpanded sheet paper.

[0434] As shown in Figure 6(C), upon expansion, the slits in the S regions open, creating cells a26 and b26. Furthermore, as shown in Figure 6(C), regions A1 adopt the leg orientations 21a described above, regions A2 adopt the leg orientations 21b described above, regions B1 adopt the leg orientations 21c described above, regions B2 adopt the orientations of claim 21d described above, regions C1 adopt the ground part orientations 20a1 described above, regions C2 adopt the ground part orientations 20a2 described above, regions D1 adopt the ground part orientations 20b2 described above, and regions D2 adopt the ground part orientations 20b1 described above.

[0436] In the embodiment shown, for example, in Figure 5(A), which employs an alternating-row expansion pattern, the open cells a26 and b26 form hexagonal peripheries that fold in at a central region, so that they do not form a regular (i.e., equilateral and equiangular) hexagon, but rather a hexagonal shape in which the opposing ground parts 20b2 and 20b1 are closer together. In contrast, as better shown, for example, in Figure 4(B), the above expansion pattern results in substantially regular hexagons. In particular, the hexagonal open cells a26 and b26 include a first half extending along a foreground plane with edges along one of the ground parts and two of the legs, and a second half extending along a background plane with edges along another of the ground parts and two of the legs. For example, an open cell b26 includes a first half along a foreground plane bounded by an edge of leg 21c, an edge of ground part 20b2, and an edge of leg 21a, and a second half along a background plane bounded by an edge of leg 21d, an edge of ground part 20b1, and an edge of leg 21b. In this application, a folded hexagon between two planes is referred to as a "folded hexagon." With reference to figures 1 and 2, 5(A) and 6(C), the folded hexagons of the b26 cells are formed so that they open upwards (i.e., so that the angle between the two planes opens upwards) while the folded hexagons of the a26 cells are formed so that they open downwards (i.e., so that the angle between the two planes opens downwards and in the opposite direction to the angle of the folded hexagons of the b26 cells).

[0438] Further analysis of preferred realizations

[0440] Figure 1 shows an explanatory plan view illustrating two slit patterns and the resulting number of cells per square meter. To this end, Figure 1 shows an explanatory plan view of the arrangement between the standard 1.27 cm wide cut 100 (i.e., a standard expandable sheet with 1.27 cm long slits) and an embodiment of the present application with a 1.14 cm wide cut 101 (i.e., an expandable sheet, according to some embodiments, with 1.14 cm long slits). In this illustrative figure, the square lines 102 and 103 represent the outline of an illustrative 30.5 x 30.5 cm rectangle representing 0.91 m² of expanded sheet material. As illustrated in this exemplary explanatory view, reducing the slit length from 1.27 to 1.14 cm results in 23.7% more legs in example 101 with a slit length of 1.14 cm.

[0441] Figure 2 is an explanatory side view depicting a cell structure of the prior art expanded slit sheet material 204 and two variable cell sizes, according to some embodiments of the present invention, 205 and 206, resulting in variable heights of the expanded slit sheet material. Reference lines 200, 201, and 203 show the variable heights of the cell structures, with line 207 being the baseline. In this illustrative figure, the expanded slit sheet 204 has a standard slit of 1.27 cm, and the novel expanded slit sheet 205, according to a first embodiment, is 10% smaller, and the expanded slit sheet 206 is 10% smaller compared to 204.

[0443] To expand a slit-sheet paper, an expansion force is required to pull the paper and open the cells. Existing slit-sheet papers can be somewhat difficult to expand and require considerably more force. In addition, existing expandable slit-sheet papers require a longer slit length to allow the cells to open. Variable slit patterns with expanded slit-sheet material require a variable force to stretch. The current slit pattern used in the market requires approximately 2.7 kg of pulling force for a 38 cm wide sheet using 2.8 kg Kraft paper. However, the present inventor has discovered that extensible paper reduces the force required for the same cut pattern and basis weight to, for example, 0.9 kg.

[0445] The present inventor has also discovered that this reduction allows for more slit pattern options that can provide greater resilience, and a reduced thickness is desirable where, previously, they were too difficult to stretch manually and placed a burden on the automated expansion equipment. In general, the present inventor has discovered that a 10% reduction in slit, ground, and row size increases the number of support legs by 23.7%, doubling the material's strength. This provides cushioning solutions that allow for greater resilience to be achieved with the same or a reduced leg height.

[0447] Furthermore, as is well known in the art of paper die-cutting, leg height affects stiffness. As leg height decreases, the die becomes stiffer. This is because the fiber length becomes more difficult to bend or flex as the height shortens. According to preferred embodiments of the present invention, leg height, the number of legs per square meter, and paper basis weight are balanced to provide optimal cushioning and minimize the pulling force required for opening.

[0449] Automated equipment is also affected by increased pulling force, as it requires more maintenance of the hook rollers due to wear proportional to the required pulling force. With the present inventor's discovery of the unique and unexpected advantages of extensible paper used in expandable slit sheet products, these pulling force-based limitations are considerably reduced, opening up greater market opportunities where increased strength is required.

[0451] Currently, there is a trend towards environmentally friendly packaging products that include the use of non-motorized equipment, eliminating the need for electricity.

[0453] The use of a manual system for dispensing rolls of expanded slit material, which can have different cushioning properties, provides greater flexibility for wrapping a wider variety of weights and densities of fragile items. For example, with the slit sheet material of the prior art, the number of wraps on a wine bottle is too large to gain a cost advantage over bubble wrap. However, with the implementation by the present inventor of an expandable wrap with a greater number of legs per square meter (e.g., according to embodiments of the present invention), fewer wraps are required to obtain the same level of cushioning. Consequently, very substantial benefits and improvements are achieved.

[0455] In some illustrative applications, preferred embodiments of the present invention can be employed in creating substantially improved, novel, and advantageous envelopes. To this end, in some embodiments, a padded envelope can be created using aspects of the present invention, providing reduced thickness but greater resilience and improved crush resistance, along with increased storage and transport efficiency, while maintaining production speed and minimizing downtime due to the reduced stretching force required by the novel use of stretchable paper.

[0457] Currently, the crush resistance for the current commercial pattern with a 1.27 centimeter indentation is 0.99 kilograms per square centimeter.

[0459] According to some preferred embodiments of the present invention, a preferred reduced slit pattern is provided using 22.67 kg Kraft paper with a slit pattern of 1.14 cm (i.e., slit length), 0.428 cm ground (i.e., distance between adjacent slits in the longitudinal direction), and 0.285 cm row width (i.e., distance between adjacent rows of slits). In some embodiments, this configuration produces a crush resistance of 1.23 to 1.32 kg per centimeter, resulting in a 27% increase in strength with a 10% decrease in thickness from 0.476 cm to 0.428 cm. In the most preferred implementations of this slit pattern, the paper employed is extensible paper.

[0461] According to other embodiments of the present invention, another preferred slit pattern is 1.01 cm slit, 38.10 cm ground, and 0.2857 cm row width. In some implementations, this latter configuration produces a crush resistance of 1.406 to 1.496 kilograms per centimeter, resulting in a 40% increase in crush resistance with a 10% decrease in thickness, from 0.476 cm to 0.428 cm. In the most preferred implementations of this slit pattern, the paper used is extensible paper.

[0463] According to preferred embodiments, this increased strength can be advantageously exploited to allow a reduced thickness of the expanded sheet slit paper, which can, for example, provide equivalent crush resistance while reducing the overall height. For example, in the above illustrative embodiments using 22.679 kg paper, using 18.143 kg paper would reduce the stiffness of the legs, but also the cost of the paper.

[0465] According to other preferred embodiments, an expandable slit paper sheet includes a pattern of cuts with slit lengths in the range of 0.762 to 1.143 centimeters and spaces between rows of slits in the range of 0.2857 to 0.4287. In the most preferred implementations of this slit pattern, the paper employed is an extensible paper.

[0467] According to other preferred embodiments, a sheet of extensible slit paper includes a slit pattern with slit lengths in the range of 1.143 centimeters plus 5% (e.g., 1.20 centimeters) to 1.143 centimeters minus 33% (e.g., 0.762 centimeters). In the most preferred implementations of this slit pattern, the paper employed is extensible paper.

[0469] According to some other preferred embodiments, an expandable slit paper sheet includes a pattern of slits that when expanded produces an expandable slit paper having a number of legs per square meter that is at least 20% greater than a slit paper sheet with slit lengths of 1.27 centimeters that is configured to create hexagonal cells (e.g., with equilateral hexagons).

[0471] According to some other preferred embodiments, an expandable slit paper sheet includes a slit pattern that, when expanded, produces an expandable slit paper having a number of legs per square meter that is at least 15% greater than that of a slit paper sheet with slit lengths of 1.27 centimeters configured to create hexagonal cells (e.g., with equilateral hexagons) and, more preferably, between 20% and 50% greater than that of such slit paper with slit lengths of 1.27 cm, configured to create hexagonal cells (e.g., with equilateral hexagons).

[0473] In the most preferred embodiments, the paper used is extensible paper, as described above. The use of such extensible paper advantageously permits a reduced slit pattern size compared to previous slit patterns. It should be noted that non-extensible paper has limitations regarding the achievable slit sizes and dimensions, and such non-extensible paper does not allow for the reduction in sizes to those of the preferred embodiments described herein, since the previous papers would be unusable and would not expand adequately if such small sizes were attempted.

[0474] Furthermore, although the present inventor has discovered new methods for improving the damping characteristics of expandable slit-sheet paper, which involve reducing the dimensions of the slit pattern, it should be noted that this reduction is not only unfeasible with the previously mentioned expandable slit-sheet paper (i.e., it could not achieve such small sizes), but also contradicts the current understanding of the damping properties offered by such expandable slit-sheet papers. It should be noted that the damping of expandable slit-sheet paper is directly related to its width in the expanded state. Consequently, to improve damping, those skilled in the art have sought to increase this width of the expanded slit-sheet paper. However, the present inventor discovered methods for achieving smaller slit patterns (e.g., by using stretchable paper) and that such smaller slit patterns with such stretchable papers could, in fact, provide better cushioning despite the cushioning losses due to the reduction in the width of the stretchable slit sheet paper. Furthermore, the present inventor also discovered other desirable applications and uses of this novel stretchable slit sheet paper.

[0476] It should be noted that non-stretchable expanded slit paper sheets do not function properly with slit lengths shorter than approximately 1.27 cm. Therefore, for smaller expandable slit paper sheets, according to the present invention, a stretchable paper according to the present invention is advantageously used.

[0478] According to some more preferred embodiments of the invention, a slit pattern is provided that includes cut lengths of 8.9 cm (i.e., the lengths of the slits), slits of 3.37 cm (i.e., the distances between adjacent slits in the same row of slits in the longitudinal direction), and a row width of 2.28 cm (i.e., the distances between rows of adjacent slits). In this regard, said slit pattern is preferably implemented within a slit pattern similar to that shown, for example, in Figure 6(A), wherein all slits in the expandable sheet have the same length, the distances between adjacent rows are consistently equal, the distance between slits in the same row is consistently the same, and the location of the slits in adjacent rows overlaps uniformly to form symmetrical cells. For these embodiments, a slit-stretchable paper is preferably employed. In particular, a non-extensible paper cannot function viably with such a slit pattern.

[0480] While, preferably, all expandable slit sheet paper would include the same slit pattern across the entire sheet, in some embodiments this pattern could be used within a portion or region of the paper and/or some regions of the paper could potentially include some differences in the pattern. Furthermore, although the lengths and dimensions of the slits are preferably the same as those indicated above, in some embodiments there could be some variations in the sizes and positions of the slits, provided that the functionality of the product is not impeded.

[0482] In some embodiments, a groove pattern with grooves of 0.889 cm, soils of 0.333375 cm and a row width of 0.222250 cm can produce a crush resistance of 1.59-1.73 kilograms per centimeter, producing a 60% increase in crush resistance with a 30% decrease in thickness from 0.476 cm to 0.285 cm.

[0484] In some preferred implementations of all embodiments of the invention described above, the ground distance (i.e., the distance SS shown in Figure 6(A) between the slits) is approximately 1/3 of the slit length (i.e., the distance SL shown in Figure 6(A)). When the distance SS is approximately 1/3 of the slit length, the lengths of the perimeter sides of the cell openings created a26 and b26 are equal. However, in some preferred embodiments, the ground distance (i.e., SS) is preferably slightly greater than 1/3 of the slit length. For example, in the above embodiments, which employ a slit length of 0.889 cm, with a ground length of 0.333375 cm, the ratio is approximately 0.952. Therefore, in this example, the length of the land is approximately 12.5% greater than 1/3 of the length of the slits.

[0486] In some preferred embodiments, the length of the land would be approximately 1/3 of the length of the slits, plus or minus 25%. In other preferred embodiments, the length of the land would be approximately 1/3 of the length of the slits, plus or minus 20%. In some preferred embodiments, the length of the land would be approximately 1/3 of the length of the slits, plus or minus 15%. In other preferred embodiments, the length of the land would be approximately 1/3 of the length of the slits, plus or minus 10%.

[0488] In other preferred embodiments, the length of the lands would be between approximately 1/3 of the length of the slits and 25% greater than 1/3 of the length of the slits. In other preferred embodiments, the length of the lands would be between approximately 1/3 of the length of the slits and 20% greater than 1/3 of the length of the slits. In other preferred embodiments, the length of the lands would be between approximately 1/3 of the length of the slits and 15% greater than 1/3 of the length of the slits. In other preferred embodiments, the length of the lands would be between approximately 1/3 of the length of the slits and 10% greater than 1/3 of the length of the slits.

[0490] In other preferred embodiments, the length of the lands would be between approximately 5% greater than 1/3 of the length of the slits and approximately 25% greater than 1/3 of the length of the slits. In other preferred embodiments, the length of the lands would be between approximately 10% greater than 1/3 of the length of the slits and 20% greater than 1/3 of the length of the slits. In other preferred embodiments, the length of the lands would be between approximately 10% greater than 1/3 of the length of the slits and 15% greater than 1/3 of the length of the slits. In other preferred embodiments, the length of the slits is such that the slit length SL is approximately determined in relation to the splitting separation SS as follows: SL = 2.6667 x SS.

[0492] In some preferred embodiments, the dimensions of the expandable slit sheet paper are reduced proportionally from an expandable slit sheet paper having a slit length of 1.27 cm, a row spacing of 0.3175 cm, and a spacing between slits within the same row (i.e., slit length) of 0.4762 cm, as follows: a) the row spacing is reduced proportionally by a ratio of SL(new)/0.5, and b) the spacing between slits is set at SL(new) multiplied by 2.6667. For example, some preferred embodiments include the dimensions indicated in the

[0493] Table A:

[0496]

[0499] In some preferred embodiments, the corresponding row spacings of Examples A to I in Table A above are substantially as shown in Table A. In some preferred embodiments, the row spacings of Examples A to I may be substantially as shown in Table A plus or minus 20% or, more preferably, substantially as shown in Table A plus or minus 15% or, more preferably, substantially as shown in Table A plus or minus 10% or, more preferably, substantially as shown in Table A plus or minus 5%.

[0501] Furthermore, in some preferred embodiments, the corresponding row spacings of Examples A to I in Table A above are, more preferably, within a range equal to or less than the row spacings shown in Table A for the respective slit lengths; in particular, with a reduced slit length, there may be greater difficulty in opening the cells, a difficulty that increases with larger row spacings. Accordingly, as the slit lengths are reduced, in some preferred embodiments, the row spacing decreases proportionally to or greater than the proportional decrease in the slit length. It should be noted that, although the present inventor discovered that the slit lengths could be feasibly reduced by using stretchable papers, as described herein, he also observed that, even with stretchable papers, the reduction in slit length may make it more difficult to open cells if the row spacings are proportionally too large.

[0503] Although Table A above shows row spacings that are substantially reduced, well below the 0.317 cm row spacing of the prior art, in some alternative embodiments, the row spacings for various embodiments of the invention (including, for example, those of Examples A to I in the Table above) can be even greater. That is, although the present invention advantageously permits such a reduced row spacing due to the greatly improved damping characteristics that allow for such a reduction (for example, the reduction in damping resulting from the reduction in row spacing can be compensated for by the improved damping characteristics of the present invention), such a substantial reduction is not necessarily required, provided that the cell structure can be opened for expansion.

[0505] For example, in some alternative embodiments, any of the embodiments of the invention having groove lengths within a range of 1.016 to 0.63 may employ row spacings that are less than those of the prior art, such as, for example, less than 0.317 centimeters or, more preferably, less than 0.304 centimeters or, more preferably, less than 0.292 centimeters or, more preferably, less than 0.285 centimeters or, more preferably, less than 0.222 centimeters or, in some embodiments, more preferably, less than 0.203 centimeters.

[0507] In other alternative embodiments, the various embodiments of the invention shown in Table A above may be modified so that:

[0509] a) the gap spacing between slits (shown in Table A as being based approximately on the formula SL = 2.6667 x SS), may be adapted to be based on the formula SL = K x SS, where K is a value between 2.4 and 3.3 or, more preferably, where K is a value between 2.5 and 3 or, more preferably, where K is a value between 2.6 and 2.8); and/or

[0511] b) the spacing between rows (shown in Table A as being roughly based on the spacing between rows being reduced proportionally in a ratio SL(new)/0.5, so that it is based on the formula RS(new) = 0.125/0.5 x SL(new) or RS(new) = 0.25 x SL(new)), may be adapted to be based on the formula RS(new) = Y x SL(new), where Y is a value between 0.2 and 0.4 or, more preferably, where Y is a value between 0.22 and 0.3 or, more preferably, where Y is a value between 0.23 and 0.27.

[0513] In all embodiments of the present invention, the paper is preferably extensible paper.

[0515] In various embodiments, extensible paper is extensible paper according to any of the embodiments or examples of extensible paper described herein.

[0517] In various embodiments, the extensible paper may employ extensibility according to any of the embodiments described herein, including, for example, any of Examples 1 through 72 described above. Furthermore, the extensible paper may incorporate features of any of the extensible papers described herein with respect to, for example, required opening forces, basis weight, or paper type, etc. However, as described herein, in embodiments employing an alternating row expansion pattern, the extensibility is adapted to achieve the alternating row expansion pattern described herein.

[0519] In some illustrative examples, in some embodiments, extensible paper is used with an extensibility range of 3 to 20% in the machine direction. In some illustrative examples, in some embodiments, extensible paper is used with an extensibility range of 3 to 20% in the transverse direction. In some illustrative examples, in some embodiments, extensible paper is used with an extensibility range of 3 to 15% in the machine direction. In some illustrative examples, in some embodiments, extensible paper is used with an extensibility range of 3 to 15% in the transverse direction. In some illustrative examples, in some embodiments, extensible paper is used with an extensibility range of 7 to 15% in the machine direction. In some illustrative examples, in some embodiments, extensible paper is used with an extensibility range of 7 to 15% in the transverse direction. In some illustrative examples, the extensible interval is not less than 5% in both the machine direction and the transverse direction.

[0521] Furthermore, in some illustrative examples, slit-sheet paper is an extensible slit-sheet configured in such a way that expansion is effected by applying an expansion force of 0.068 to 0.099 kilograms per centimeter to form such open cells.

[0523] Furthermore, in some illustrative examples, the slit-sheet paper is an extensible slit-sheet, wherein said slit-sheet paper has a basis weight, before expansion, of approximately 13.6 to 22.6 kilograms per 914.4 square meters. It is noteworthy that all embodiments of the invention described herein (e.g., the various slit patterns, including slit lengths, slit spacing, row spacing, etc.) can be employed in various paper implementations with basis weights within this range in some embodiments, such as, for example, in 13.6 kg paper, 18.14 kg paper, 22.6 kg paper, and any paper within this range. Furthermore, in other embodiments, papers with a basis weight lower than this range of 13.6 kg to 22.6 kg, such as 9.07 kg or less, or with a basis weight higher than this range, such as 27.21 kg or more, can be used. However, in preferred embodiments, due to the improved cushioning characteristics achieved, papers with lower weights can be used while obtaining the same or even better cushioning characteristics than the previous expandable slit-sheet papers.

[0525] As previously stated, with the present invention, expanded slit sheets with significantly improved damping characteristics can be created. The improvement in damping characteristics can be achieved through one or more, or all of the following elements:

[0527] a) In preferred embodiments, the use of an extensible paper allows for an "easy-opening" structure, which facilitates the creation of smaller cells, advantageously leading to a higher cell density and thus better damping characteristics.

[0528] b) In some of the preferred embodiments, the use of an extensible paper makes it possible to achieve a novel "alternating row expansion pattern" which has substantially improved damping characteristics compared to previous expansion patterns.

[0530] As indicated above, with the present invention, novel and previously unfeasible damping products can be created, such as:

[0532] a) In some preferred embodiments, a new envelope structure can be achieved with significant advantages over existing envelope structures. For example, the present invention allows for a substantially thinner expanded slit sheet with cushioning (e.g., with substantially smaller row spacing) and also provides substantial cushioning with a single layer or only a few layers. Consequently, an envelope with a much narrower width, and even with only a single layer of cushioning, can be achieved. Furthermore, the envelope can be manufactured from lighter paper, resulting in a product that is easier to use (e.g., less rigid) and lighter (e.g., with reduced shipping costs). It is worth noting that the lower weight of the product, along with the narrower width, translates into reduced shipping costs.

[0534] b) In some preferred embodiments, a novel damping envelope can be achieved which has great advantages over existing damping envelopes such as, for example, greater damping characteristics, allowing, for example, the reduction of the damping layers required in some applications, the reduction of the amount of damping required, and other advantages and benefits as described herein.

[0536] Broad scope of the invention

[0538] Although illustrative embodiments of the invention have been described in this document, the present invention is not limited to the various preferred embodiments described herein, but includes each and every embodiment that falls within the scope of the claims.

Claims (20)

1. CLAIMS 1. A slit-sheet paper cushioning product comprising: at least one slit-sheet paper having a slit pattern that includes a plurality of slits extending in a transverse direction that form a plurality of open cells when expanded in a machine direction, said slit-sheet paper is formed from an expandable paper that expands in an alternating row expansion pattern that includes alternating rows with cell openings on the underside (a26) in lower rows (R-a) located on a lower side of the expanded slit-sheet paper and with cell openings on the upper side (b26) in upper rows (R-b) located on an upper side of the expanded slit sheet paper, wherein said slit sheet paper is made of extensible paper, wherein said extensible paper is extensible in a machine direction by an interval of at least 5%. 2. The slit-sheet paper cushioning product according to claim 1, wherein said extensible paper is extensible in the transverse direction by an interval of at least 5%. 3. The slit-sheet paper cushioning product according to claim 1, wherein: - said extensible paper is extensible in the machine direction by an interval of at least 5% and in the transverse direction by an interval of at least 5%, or - said extensible paper is extensible in the machine direction by an interval of at least 7% and in the transverse direction by an interval of at least 7%, or - said extensible paper is extensible in the machine direction by an interval of at least 8% and in the transverse direction by an interval of at least 8%. 4. The slit-sheet paper cushioning product according to claim 4, wherein: said extensible paper is extensible in one machine direction by a range of between 5% and 15% and in a transverse direction by a range of between 5% and 15%, or This extensible paper is extensible in one machine direction by an interval of between 7% and 15% and in a transverse direction by an interval of between 7% and 15%. 5. The slit-sheet paper cushioning product according to claim 1, wherein: - said plurality of slits each has a width of between 0.89 and 1.65 centimeters, or - wherein said plurality of slits each has a width of between 1.14 and 1.39 centimeters. 6. The slit-sheet paper cushioning product according to claim 1, wherein each of said slits has a width of approximately 1.3 centimeters. 7. The slit-sheet paper cushioning product according to claim 1, wherein - said plurality of slits each has a width of less than 1.3 centimeters, or - said plurality of slits each has a width of less than 1.14 centimeters, or - said plurality of slits each has a width of less than 1 centimeter. 8. The slit-sheet paper cushioning product of claim 1, wherein the ground portions (20) formed in the regions between the ends of the slits in the same row of slits are formed in upward- and downward-oriented portions. 9. The slit-sheet paper cushioning product of claim 8, wherein each ground portion (20) includes a folded or angled portion aligned between adjacent slits within the same row of slits, around which the tilt angles between the two parts of the ground portion change. 10. The slit-sheet paper cushioning product according to claim 8, wherein the ground portions (20) in the first-type rows (R-a) include a first portion extending from an edge of an open cell on a left side of the ground portion upwards to the folded or angled portion in the center of the ground portion, and a second portion extending from the folded or angled portion in the center of the ground portion downwards to an edge of an open cell on a right side of the ground portion. 11. The slit-sheet paper cushioning product according to claim 10, wherein the ground portions (20) within the second-type rows (R-b) include a configuration opposite to that of the first-type rows, and include a first portion extending from an edge of an open cell on a left side of the ground portion downwards to a folded or angled portion in the center of the ground portion, and a second portion extending from the folded or angled portion in the center of the ground portion upwards to an edge of an open cell on a right side of the ground portion, wherein the slit-sheet paper cushioning product includes said first-type rows and second-type rows alternating throughout the slit-sheet paper in an expanded state. 12. The slit-sheet paper damping product according to claim 1, wherein the open cells (a26, b26) have hexagonal peripheries that are folded in a central region so as to form a hexagonal shape in which the opposite ground parts are closer to each other. 13. The slit-sheet paper cushioning product according to claim 11, wherein the hexagonal open cells (a26, b26) include a first half extending along a first plane with edges along one of the ground parts and two of the legs, and a second half extending along a second plane with edges along another of the ground parts and two of the legs. 14. The slit-sheet paper cushioning product according to claim 1, wherein the open cells (a26, b26) are formed in alternating rows, a first of the alternating rows having a row of open cells formed so as to open upwards and a second of the alternating rows having a row of open cells formed so as to open downwards. 15. The slit-leaf paper cushioning product according to claim 1, wherein said slit-leaf paper is a roll of slit-leaf paper. 16. The slit-leaf paper cushioning product according to claim 15, wherein said slit-leaf paper roll is supported on an expanding device adapted to rotatably hold the slit-leaf paper roll for manual extraction and expansion of said slit-leaf paper from said roll. 17. The slit-leaf paper cushioning product according to claim 1, wherein said slit-leaf paper is used within a wall of an envelope to cushion the envelope. 18. The slit-leaf paper cushioning product according to claim 17, wherein said envelope includes a single layer of said slit-leaf paper within the envelope wall for cushioning so as to reduce the wall thickness. 19. The slit-leaf paper cushioning product according to claim 17, wherein said wall of said envelope includes an outer paper layer located on a first face of said slit-leaf paper and an inner paper layer on a second face of said slit-leaf paper. 20. A method of using the slit-leaf paper cushioning product according to claim 16, comprising manually wrapping the expanded slit-leaf paper around an article, thereby creating multiple layers of expanded slit-leaf paper surrounding it for cushioning.