CN1309328C - Stretched fasteners - Google Patents

Abstract

A running length of fastener product (10) is formed of longitudinally pre-oriented synthetic resin. The product is characterized by a base web and an array of discrete fastener elements (A) protruding from at least one side of the web (12) being in a laterally stretched molecular oriented condition. After forming a preform having discrete fastener elements (11) integral with a base web (12) in a stretchable state, the preform is stretched in a manner that substantially increases the fastener element spacing and reduces the thickness of the base web (12). A machine (40) is shown that is capable of lengthwise orienting before forming and widthwise stretching after forming, which employs controlled heating to render the product widthwise stretchable while preserving or achieving a desired shape of the fastener elements (11). There are shown fastener products (10) that include products that are laterally stretched to between two and ten times the width of the original preform fastener products (10), having lateral rip resistance due to molecular orientation of film form webs (12) produced by stretching, applied to complex or extensive surfaces. Also shown are laminated products formed by joining an added material to the stretched web (12), and methods for laminating.

Description

stretched fasteners

technical field

This invention relates to synthetic resin sheet-form fasteners and methods and machines for making them.

Background technique

An important aspect of the present invention pertains to hook and loop fastened hook fasteners. They are made of synthetic resin in continuous lengths. Typically multiple fasteners are used, ie hundreds or even thousands of discrete hooks per square inch. These are generally aligned in the machine direction, ie the direction in which the product is produced by the forming system.

The hook members stand discretely from at least one side of a unitary strip-shaped base. The base forms a means for attaching the fastener to the item on which it is carried.

The fasteners of these hooks generally have an aesthetically pleasing, uniform, commercially acceptable appearance in distribution and are widely used in consumer and industrial products.

In one preferred method of manufacture, molding rolls are used, such as that described in Fischer, US Patent No. 4,794,028. This method produces a commercial looking hook fastener in which the rows of hooks are straight and the spacing between the hook elements in both directions is regular.

Forming the molded roll of this type of preferred fastener generally includes a series of thin circular plates, the molded plates alternating with spacer plates. A molded plate is peripherally machined with cutouts defining small hook profile cavities. A set of plates are fixed such that their peripheries cooperate to define the surface of the roll. Because a large number of such plates are required and the plates must be carefully maintained in alignment, such rolls are expensive to produce and maintain, and are generally limited to short lengths. The width of the manufactured product is correspondingly limited.

Conventional fastener material produced in this method is less than one or two feet wide and has a web thickness greater than 0.005 inch, typically 0.008 inch, between the hooks. Generally, the hook faces are in the machine direction, or the opposite direction, in this manufacturing method, so that their principal peel and shear strengths are oriented similarly.

The present invention, in its broadest aspects, will be described to form synthetic resin fasteners by techniques other than the molding techniques described above. Using these techniques, such as utilizing known cutting and stretching techniques on an extruded preform, discrete fastener distribution areas are also erected from the base and the fasteners are aligned in rows extending in the machine direction. This makes the orientation of the hooks perpendicular to the machine direction, and their primary peel and shear strengths are in this direction. Existing equipment and methods for making such devices are limited in the width of the finished product and the minimum thickness of the web that can be achieved between the fastener elements.

The present inventors have discovered that it is possible to obtain commercially acceptable thin synthetic resin fasteners in which the web or substrate between multiple fasteners is permanently stretched in the transverse direction, and in many cases the web material has a At least partially molecularly oriented.

It has also been discovered that the portion of the web between adjacent fastener elements can be stretched to a uniform thickness across the width of the product while maintaining the uniformity and working shape of the overall discrete fastener elements. Ideally, the portion of the web between the fastener elements is reduced to a film thickness and the resulting fastener can conform to curved or complex surfaces, or otherwise be economically applied to a wide area.

Contents of the invention

According to an important aspect of the present invention, the method for manufacturing thin fasteners includes the steps of: (1) longitudinally stretching a heat-softened synthetic resin sheet to pre-orient the molecular structure of the sheet in the longitudinal direction; Molding a continuous web from a sheet having a base and a plurality of discrete fastener elements integral with the base protruding from at least one side of the base; (3) then, under conditions where the web is permanently stretchable, the Lateral stretch webbing permanently stretches the base and increases the lateral spacing of the fastener elements.

In particular embodiments, the fasteners include contact fastener hooks and the like.

In preferred embodiments, the transverse molecular orientation strength of the fastener article and the peel strength of the fastener increase during stretching.

In preferred constructions, the ratio of the final width of the product to the original width prior to width stretching is between about 2 to 1 and 10 to 1, and the width stretching reduces the web base thickness by at least 50%.

In certain constructions, the transverse stretching widens the web by at least 200% and reduces the thickness of the base of the web between the fastener elements by at least two-thirds.

In another implementation, the method includes heating the web so that the base of the web can be permanently stretched without adversely changing the shape of the fastener. In some arrangements, the fastener extends from only one side of the web, heating the web primarily from the opposite side having the fastener.

In some examples, the resin is a thermoplastic resin suitable for forming the hook, including polypropylene, polyethylene, polyester, polystyrene, PVC, nylon, or copolymers or polymer blends thereof.

In certain preferred constructions, the transverse stretching process results in molecular orientation and strengthening of the web base between fastener elements during stretching such that the web base between fastener elements stretches generally uniformly throughout in the transverse direction.

In some cases, the synthetic resin has a characteristic minimum elongation, and the molded roll root defines a predetermined pattern of fasteners and other elongation-limiting components in the region of the web. The graphic structure is selected such that the ratio of the final web width to the web width before transverse stretching is substantially smaller than the characteristic minimum elongation. In certain implementations, the fasteners and the extension limiting member resist localized elongation of the web. The elongation-limiting member is a structural part of a product made of resin integral with the base of the webbing by means of differentially heating the webbing under manufacture so that the fasteners and extension-limiting members are more extensible than the base of the webbing. The length is small.

In some constructions, the temperature of the base of the web is controlled as the web is stretched in the transverse direction. For example, the fastener may be immersed in a temperature-controlled fluid while stretching in the transverse direction. In other examples, the web substrate is immersed in a temperature-controlled liquid while stretching in the transverse direction, or the web substrate is heated in a heated liquid bath while stretching in the transverse direction, while the fastener elements remain exposed to the atmosphere.

In some embodiments, a double stretch process is used, wherein the step of laterally stretching the webbing includes transversely stretching the webbing in a first stretch zone, then maintaining the webbing at an intermediate stretch width, and then stretching the webbing in a second stretching zone. The stretch zone stretches the webbing in the transverse direction. The transverse stretching speed preferably varies along the first stretching zone.

In another aspect of the present invention, there is provided a method of making a low profile fastener product comprising (1) forming a continuous web from a synthetic resin, the web having a plurality of discrete rows extending integrally from at least one side of the web. Fasteners with the fasteners facing substantially longitudinally; (2) Then, under conditions where the webs can be permanently stretched, stretching the base of the webs in a biased direction so that the bases of the webs between the fasteners are permanently stretched, increasing The fastener elements are spaced and oriented with rows of fastener elements oblique to the machine direction such that the fastener elements face in an oblique direction.

In another aspect of the present invention, a method of manufacturing a layered thin product having fasteners includes (1) forming a continuous web from synthetic resin, the web having a pattern extending from one side of the web base. a plurality of discrete fastener elements integral with the base of the web; (2) then, under conditions where the base of the web can be permanently stretched, stretch the base of the web transversely to a wider width such that the The base of the web stretches to increase the spacing of the fastener elements in the transverse direction while substantially maintaining the longitudinal spacing of the fastener elements; (3) bonding an additional material to the opposite side of the web.

In some embodiments, the bonding includes passing the additional material and the web over a roll under conditions where the web substrate is thermally softened.

In other embodiments, the bonding includes applying an adhesive to the additional material, or to the web base, or both, and guiding the additional material and web together to form a laminate.

In further embodiments, bonding includes heat softening the surface of the add-on material, and passing the add-on material and the web over a roll such that the web base is bonded to the heat-softened surface of the add-on material.

In a preferred embodiment, bonding includes bringing the add-on material and the web together so that the base of the web adheres to the heat-softened surface of the add-on material, sometimes by pressing the add-on material and the web together against a roller .

In another aspect of the present invention, a method of making a low-profile fastener includes (1) forming a continuous web of synthetic resin having a plurality of connecting webs extending from at least one side of a web base in a patterned configuration. Discrete fastener elements integral with a base that pre-orients the molecular structure of the web in the longitudinal direction; (2) then stretching the web in the transverse direction under conditions where the web base is permanently stretchable such that The webbing between the fasteners is permanently stretched to increase the spacing of the fasteners in the transverse direction while substantially maintaining the longitudinal spacing of the fasteners.

In another aspect of the present invention, a fastener product is constructed of synthetic resin and has rows of fastener elements oriented in a first direction along the base of the web. Portions of the web between rows of fastener elements have a molecular orientation at an angle to the first direction.

In a preferred implementation, the fastener elements comprise hook elements whose profile is oriented in an oblique direction relative to the continuous length of the web.

In some cases, the webbing substrate in the stretched state comprises a thermoplastic film having a thickness of less than 0.003 inches. In certain cases where the product is bonded to a non-planar surface of a utility product, the film attachment tape conforms to the non-planar surface.

In certain embodiments, the product has a width of eight feet or more.

In certain preferred embodiments, the product has molecular orientation in the transverse direction, resulting in tear strength in the longitudinal direction. In certain key embodiments, the product also has molecular orientation in the machine direction, resulting in tear strength in the transverse direction.

In another set of embodiments, a decorative layer comprises said product and sheet material in a laminate, the fasteners of said product forming a means for securing said layer in a desired position. In some examples, the decorative layer includes a wall covering. In other instances, it includes a floor covering.

In another aspect of the invention, a fastener forming machine has a pair of rollers forming a nip, at least one of which is a molded roller, forming a contact fastener integral with a continuous length of side surface of a web base. The machine also includes means for supplying plastic resin to the nip so that the resin is longitudinally stretched prior to molding, and a widthwise stretching means is provided for transversely stretching a continuous length of the base of the connecting strip in the middle made by the pair of rolls The connection belt base of the product.

In a preferred embodiment, the machine comprises a heated tunnel through which the intermediate product passes before the stretching device. The heating tunnel is provided mainly to heat the side of the connecting strip opposite to the side where the fastener is located.

In a special-purpose implementation, the means for supplying the plastic comprises an extruder, and the supplied resin is stretched longitudinally by tension generated by driven rollers, pre-orienting the molecular structure of the resin in the machine direction prior to forming.

In another aspect, the means for supplying plastic resin comprises an extruder which may be positioned above the nip, the supplied resin being at least partially stretched longitudinally by inertial forces as it falls from the extruder into the nip.

In another practical arrangement, the machine also includes means for laminating additional material to the stretched web base. In a preferred embodiment, the laminating device comprises a roller around which the product is drawn in the direction of stretching.

Description of drawings

Fig. 1 and Fig. 2 are the side view and the plan view of the device of the present invention manufacture product;

Figure 1a is an alternative source of connecting straps that can be stretched in the systems of Figures 1 and 2;

Figure 3 is an enlarged plan view of the product before transverse stretching taken at line 3-3 of Figure 1;

Figures 3a and 3b are cross-sectional views taken along Figures 33a-3a and 3b-3b, respectively;

Figure 4 is an enlarged plan view of the finished product taken along line 4-4 of Figure 1;

Figure 4a is an enlarged plan view of the completed fastener product, where the fastener is set at an inclination angle relative to the processing direction;

Figure 4b is an enlarged plan view of the finished product stretched in both width and machine direction;

Figure 4c is an enlarged view of the finished product with fasteners of different shapes;

Figure 4d is an enlarged view of a product with an additional restraining stretch structure;

Figures 5 and 6 are sectional views of the finished product taken along corresponding lines in Figure 4;

Figures 5a and 6a are cross-sectional views taken along corresponding lines in Figure 4a;

Figures 5b and 6b are cross-sectional views taken along corresponding lines in Figure 4b;

Figures 7 and 8 are side and end views, respectively, at high magnification of the fasteners of Figures 5b and 5c, showing changes in cross-sectional dimension of the product during stretching;

Figures 7a-7d are diagrams of various fasteners that may be used;

9-10 are side views of an object to which the fastener of the present invention is secured;

Fig. 11 is a schematic plan view of a stretching frame for product stretching in an oblique direction;

Fig. 12 is a view similar to Fig. 11 showing the frame stretched both widthwise and longitudinally with the direction of the biased fasteners;

Figure 13 is a view similar to the left hand portion of Figure 1, with additional means for introducing a prefabricated fabric to the back of the web;

Figure 13a is a cross-sectional view of a product formed by the apparatus and method of Figure 13;

Figure 14 is a view similar to the left hand portion of Figure 1, with a dual extruder supplying the nip with liquid resins of two different compositions;

Figure 14a is a cross-sectional view of a product made by the machine and process of Figure 14;

Figure 15 is a view similar to the left hand portion of Figure 1, including a plurality of molding rolls forming a product with protrusions on both sides for the various resins that make up the product;

Figure 15a is a cross-sectional view of a product formed by the apparatus and process of Figure 15;

Figure 16 is a diagram of radiation heating in a preheating furnace before transverse stretching;

Fig. 17 is the machine scheme diagram of Fig. 1 to the stretched connecting band laminated lining;

Figures 18-20 are technical drawings of the additional laminate bonding process;

Figure 21 is a two-speed zone stretching diagram;

22-23 are side and plan views of the fastener holding fluid bath while the web is stretched;

Figure 24 is a view of the base of the connecting tape heated in a liquid while exposing the fastener to air while stretching;

Figure 25 is a two-liquid temperature-controlled stretching liquid bath;

Fig. 26 is a graph showing tension of the fastener while controlling the temperature of the web and the fastener in a single fluid medium.

Detailed ways

1 and 2, a forming apparatus 13 utilizes a rotating molding roll 14 to mold a product 10 of synthetic resin, a continuous web 12 having a plurality of discretely spaced fasteners integral with the base web 11. As shown in Figure 1, molding roll 14 is associated with a pressure roll 16 to define a forming nip. The periphery of the mold roll has discrete mold cavities, each cavity shaped to form a profile of the fastener as shown enlarged in FIGS. 7 and 8 . An extruder 18 extrudes the liquid plastic resin 20 into the nip and forms a web with a plurality of discrete fastener elements protruding from one surface. After passing the take-off rollers 22, the shaped product can pass through the stretching device shown in FIGS. 1 and 2 .

Alternatively, instead of sending the product 10 from the forming unit 12 directly to the stretching system shown in Figures 1 and 2, it is also possible to collect the product in storage rolls and transfer it from the storage rolls to the stretching system at another time. FIG. 1 a shows a table 24 on which storage rolls 10 a of material preformed by the forming device 12 are mounted. The feed stock passes around idler rolls 26 and 28 and is supplied to the stretching system of Figures 1 and 2, as shown in Figure 1, as a batch rather than an inline process.

In any of the above processes, the product 10 enters the stretching system, which includes a preheater 32, a transverse stretching mechanism 40 and a cooling unit 42. The finished product can then be wound onto a roll or otherwise placed.

In any of the above processes, the product 10 enters the stretching system, which includes a preheater 32, a transverse stretching mechanism 40 and a cooling unit 42. The finished product can then be wound onto a roll or otherwise placed.

See the enlarged product view of Figure 3, the upper surface of the connecting strap 12 has a plurality of discrete upstanding hook elements 11, in this case suitable for fastening according to the hook and loop technique. Alternating rows of hooks may face in opposite directions, the rows of hooks being aligned with the machine direction T which coincides with the turning of the molding roll 14 .

Before entering the preheater 32 , the product is engaged by the clamps 30 of the stretching frame running with the product on rails, thus transporting the molded product through the preheater 32 and the cross stretching device 40 .

As shown, the downstream, smooth surface of the web of product 10 is exposed to a distributed flow of hot air generated by a source 34 of heated air and directed toward the preheater through plenum 36 and distribution nozzles 38. of.

The upper surface of the connecting strap 10 and the discrete fasteners 11 are exposed to the residual air flow at a lower temperature contained by the walls of the preheater 32 . As a result, most of the heat can be directed to the lower surface of the product in a controlled manner, keeping the fastener 11 on the upper side at a temperature sufficiently low that the fastener does not undergo detrimental deformation during preheating and stretching.

The product 10 in the preheater 32 is heated approximately above the glass transition temperature and below the melting temperature of the synthetic resin forming the product. Due to the predetermined arrangement of the guide rails, until the final stage of the preheater 32, the stretch frame jaws 30 maintain a fixed lateral spacing corresponding substantially to the forming width of the product 10. At the final point, the known tension frame jaws 30 begin to expand. The expansion of the chuck 30 on the stretching device 40 until it reaches the maximum width, which is substantially in the middle of the stretching device as shown, after which the stretching frame track can continue in parallel for a selected distance, and then gradually Collapse to a stable final width W. The product passes through the cooling device 50 in width W for cooling and stabilization of the material.

4, passage of the product through preheater 32, stretching unit 40 and cooling unit 50 results in the web being permanently stretched in the transverse direction and the spacing between the discrete rows of fastener elements increasing with a predetermined rate of elongation. This elongation is chosen to exceed the characteristic minimum elongation of the resin as specified below. Comparing the before and after enlarged views of the products of Figures 3 and 4, it can be seen that the original spacing W ₀ of the rows of fasteners 11 of Figure 3 is increased to the spacing W ₁ of Figure 4, which is much larger than W ₀ . Depending on the desired product, the properties of the resin being processed and other parameters, the spacing W ₁ can vary by about 2-8 times the original width W ₀ . Because the chuck 30 of the stretching frame in this example moves at a speed _V1 , which in this embodiment is substantially constant throughout the stretching system, in the processing direction T _is represented by _L0 in FIGS. 3 and 4 The longitudinal spacing of the discrete hook elements does not vary appreciably.

In certain examples, width stretching is performed in two or more different zones as shown in FIG. 21 . In the first zone Z ₁ the product width is stretched to an overall stretch ratio of about 2.5:1 and thereafter held at the intermediate width for at least a few seconds to allow a second stretch in zone Z ₂ to a final stretch ratio of about 6:1. The overall stretch ratio is greater than that of the former, achieving partial stabilization. As shown, the stretching frame track in the stretching region is curved (as a cosine), gradually starting and ending the lateral acceleration of each stretching cycle. The first stretching cycle establishes the desired molecular orientation on the bonded belt base. This dual-speed zone stretching setup allows sensitive resins to achieve greater ultimate elongation, avoiding process-induced localized stress concentrations that could cause tearing at the root of the hook.

Under the transverse stretching condition, the thickness of the material of the base web 12 is reduced from the original t ₀ of FIGS. 3A and 3B to the reduced thickness t ₁ of FIGS. 5 and 6 . The areal density of the fastener is thus reduced. For example, a hook shape having a conventional height of about 0.035 inches along a row with a spacing _L of about 0.050 inches begins with a row spacing _W of about 0.025 inches and _ends at the spacing W of Figure 4 of 0.100 inches, with an areal density by a factor of 4 Varies from about 800 fasteners per square inch 11 to about 200 fasteners per square inch. When a greater final hook element density is desired, such as greater hook fastener 11 and loop fabric engagement peel and shear strength, adjustments can easily be made, for example, by reducing the original transverse row spacing W _. , or reduce elongation.

In another example utilizing smaller discrete fasteners, the areal density may vary from about 2000 to 1000 or 500 per square inch, for example. Several different fastener constructions with different areal densities are available.

Therefore, the stretching process is carried out under the condition that the base webbing 12 can be permanently stretched, and the webbing 12 is permanently stretched to a desired degree of webbing stretching, and the spacing of the fasteners 11 of the product 10 is increased. Several other arrangements may also be utilized, some of which are described later in this specification.

In the preferred embodiment shown in Figures 1 and 2, the web is rendered permanently stretchable by heating. Using heated air and avoiding directing hot air towards the top surface of the webbing 12, which now carries integral molded fasteners, the fasteners 11 are protected from the heating of the lower surface and body of the webbing. It was found that stretching the web 12 under these conditions did not damage the shape of the fastener hooks. The amount of expansion of the stretch frame clamps 30 and the final dimension W to which the web is stretched will vary depending on the resin used and the properties to be achieved in the final product.

In general, a given resinous material, such as a flat sheet, has a characteristic minimum elongation rate (CMSR) at a given stretching condition defined by said condition, i.e., if the sheet does not exceed this minimum rate Stretching outside produces an uneven product with wrinkles and dents. If the CMSR is exceeded, full-area stretching can be ensured and a generally flat final product can be obtained. This parameter is determined from the stretching that occurs on a microscopic scale. In general it reflects that molecular orientation occurs at the stretch and that the strength of the oriented flake regions increases. Given the microscopic stretching action and over very short time intervals, the sheet does not always have a precise uniform thickness, or be heated to a precise consistent temperature and overall stretchability. This affects the way the process is carried out. In the initial stages of the process, stretching occurs in the most stretchable regions until those regions of the sheet become stronger and more resistant to stretching through progressive molecular orientation in these regions. As this occurs, the stretching action is diverted to previously unstretched areas, and so on. If stretching is performed for a sufficiently long time and the CMSR is substantially exceeded, a uniform stretching effect is produced by which all regions of the sheet undergo some stretching sufficient to achieve a flat uniform appearance. product.

In the embodiment of Figures 1 and 2, the longitudinal velocity of the stretching frame jaws 30 remains constant substantially the entire length from the preheater to the cooling unit.

See Figure 4a and the representation of the stretching frame grips in Figure 11. In another process, the grips along one side of the product pass through the preheater 32 and the stretching device 40 at a velocity _V1 . However, on the other side of the product, the collet chain is divided into two active parts. The first section through the preheater 32 runs at speed _V1 , the same speed as on the opposite side. In the second part, within the stretching device 40, the longitudinal velocity of the collets increases gently to a velocity _V2 greater than velocity _V1 . As shown by arrow D in Figure 11, this has the effect of applying a tensile force to the web material in a diagonal or inclined direction and causing the row of fastener elements to reposition to the relationship shown in Figure 4a. The rows of fastening elements form an angle α with respect to the machining direction T. The material of base web 12 now has a molecular orientation defined in the tilt direction due to stretching in a tilt direction corresponding to the direction of the reorientation row of fastener elements. Pre-stretching in the machine direction is not required here, but can be used. Fasteners in oblique stretch products may have more effective hooks for peel and shear in the transverse direction than the same fastener produced by processing the product of Figure 4 when their structural components are in the transverse, or cross-machine, direction. and ring fastening.

Due to the arrangement of the resin extruder 18, the molding and pressure rolls 14 and 16 and the included nip, the extruded resin is pulled, or longitudinally extruded, when entering the nip, so that the resin molecular chains of the substrate-attached tape are Pre-orientation parallel to the longitudinal direction of the row of fastener elements 11 prior to fabrication. In general, the degree of longitudinal preorientation increases with the speed of the extrusion and molding process. The benefit of this pre-orientation of the web is to strengthen the web in the machine direction and reduce the longitudinal tear strength for operations requiring subsequent splitting. Using special dies in the extruder 18, such as a coat hanger die, enables a gravity fed system in which the extrusion connection of the liquid resin is between the forces of inertia as it falls into the nip. The longitudinal stretching can strengthen this longitudinal pre-orientation.

In a machine with an extruder without longitudinal pre-orientation, a stretch frame as shown in Figure 12 can be used to stretch molded webs longitudinally and transversely as the web enters the nip, producing the web shown in Figure 4b The product. At this point, the grippers on both sides of the stretching device are divided into two parts. As the connecting strip passes through the stretching frame 40, the first section on each side passes continuously through the preheater 32 at a velocity _V1 and the second section of the collets runs at a greater velocity _V2 . This has the effect of stretching the web longitudinally as well as transversely, causing a biaxial resin orientation of the web material and increasing the spacing of the hook-shaped fasteners to a width of _W3 and a length of _L3 correspondingly greater than that of Figure 3 The original width W ₀ and length L ₀ are shown. The disadvantage of this particular method is that post-stretching in the machine direction limits the amount of transverse stretch that can be applied to the molded webbing, thereby limiting the achievable width of the final product.

Figure 4c shows another product that can be produced by the method of the present invention, wherein in addition to the discrete securing hooks 11, there are structures 60 attached to the hooks that enhance the overall performance of the product. The post-forming width stretching process is effective for such products.

In Fig. 4d, the surface structure 90 is defined upon heating in a pattern predetermined to limit the stretchability of the entire product. At this point, the hook-shaped fastener 11 and the further stretch-limiting structure 90, for example, maintain a lower temperature and cooperate to limit the stretchability of the entire preform. By proper selection, the fastener 11 and additional structure 90 provide a specifically designed product and, under selected process conditions, form an effective minimum elongation that is substantially less than that of a conventional flat sheet of the same thickness as the product attachment strip 12. CMSR. The preforms are made in such a way that they are processed in a stretching frame in a way that differs from the direct determination of the CMSR of the common resin connection strips. By proper selection of the structure and size and location of the hook elements, the effective CMSR of the preform can be adjusted, thus varying the amount of stretch that can be achieved. This enables the production of fastener products with different properties as required. In the case of polypropylene, the CMSR is generally about 6:1 to 8:1. However, by properly selecting the areal density, spacing and size of the hook members 11 and the areal density, spacing and size of the stretch-limiting additional structures 90, and their interrelationships, the effective CMSR of the product can be varied over a considerable range of applications. , for example as small as 4:1 or 2:1. The same resin, such as polypropylene, can be used to form products with several expansion ratios by proper selection of parameters.

Figures 7a-7d illustrate some of the various other types of fasteners. The microhooks of Figures 7a-7d have a height of 0.03 inches, down to 0.015 inches or less. These are useful for fabrics that include fine matching loops of low top non-woven fabrics. The fastener of Figure 7c is palm tree shaped with a height of about 0.100 inches and is useful, for example, for crinkling of upholstery fabrics in securing chambers and the like. Figure 7d shows a mushroom shaped fastener which can be engaged with a similar arrangement of mushroom fasteners of the opposite fabric. This is by way of illustration, in a broader aspect the invention is applicable to other forms of molded fasteners. These are four of a variety of hook configurations suitable for hook and loop fastening that may be used in products made in accordance with the present invention.

See the higher magnifications of FIGS. 7 and 8 , the dotted parts of the figures represent the original molded product as it leaves the forming device 13 . The effect of heating and stretching reduces the thickness of the web 12 as shown by the solid lines. Stretching across the width can significantly reduce the thickness of the connecting tape in terms of elongation.

In certain instances it is preferable to reduce the thickness of the web to a thin film, ie a thickness of less than 0.003 inches for thick films, or about 0.001-0.002 inches for thin films. This membrane has great adaptability to complex surfaces. In some cases it is flexible enough to be smoothly added to curved surfaces, such as cylinders, or to be thermoset. In other instances, the final thickness of the web and the synthetic resin from which it is molded are chosen to affect the stretching of the overall product so that it can be spread over complex surfaces.

In some instances it may be advantageous for the product to bond to an item which increases the strength of the overall fastener. When heated by a flash, bonding can be done using the adhesive properties of the back of the resin bonding tape itself, or by applying an adhesive layer, or by utilizing the bonding properties of the surface it is applied to, or by combining two or three of these methods. be used in combination or with other bonding techniques including ultrasonic welding.

A complex surface to which fasteners made according to the present invention are shown in FIG. 9, wherein the thickness of the base web of the product is reduced to a selected thickness of 0.001-0.002 inches. The filmy nature of the connecting tape in this product makes it conformable and, if desired, stretchable to conform to complex surfaces. In Figure 9, the shapes are arbitrary, showing that several shapes can accept such fasteners.

A broad surface is shown in the sketch in FIG. 10 . For example, the interior surface of an office partition, such as 5 feet by 7 feet, is glued to it according to a sheet of the material of the present invention. An evenly covered array of hooks is formed over the entire surface according to the desired material. Such a surface can accept a ring at any point and hold it securely. In this way and at a lower cost, partitions of contrasting colors can be incorporated; signs and artwork can be installed on walls, ceiling tiles can be fixed, floor layers can be fixed, etc.

7 and 8, the dashed lines show that the height of the hook fastener before heating is greater than after the heating and stretching treatment. Due to controlled surface melting combined with gravity and surface tension effects, depending on the controlled amount of heat applied to the fastener in preheater 32, a specific amount of surface flow of material from the fastener will occur resulting in shortening. This will give the outer surface of the hook fastener a desired effect, such as a softer and more comfortable feel against the skin when touched.

In other instances, it may be desirable to preserve the exact molded shape of the fastener 11, to avoid shape changes by reducing the applied heat, or to protect the fastener when the web is heated. At this point, the tension applied to the web when stretched extends into the lower temperature protruding fastener structures and effectively pulls these stiffer structures into the relatively softer web material.

As shown in Figures 22 and 23, one method of protecting the fastener while stretching is by using a shallow temperature-controlled liquid bath 120. In this example, only the fastener element 11 is immersed in the liquid bath during width stretching, and the webbing base 10 is exposed to air at a temperature higher than that of the liquid bath. The stretching rack track 31 is arranged to lower the connecting straps to soak the fastener while stretching and to lift the product from the liquid bath after stretching.

In another version shown in Figure 24, the lower surface of the webbing base 10 is immersed in a heated temperature controlled liquid bath while the fastener elements 11 are exposed to cooler air. In another solution (FIG. 25), using two immiscible liquids 125 and 126 maintained at different temperatures, the connecting strip runs along the interface between the two liquids, acting as a thermal barrier and reducing heat transfer between the layers. In each approach, liquid baths are used to relatively precisely control the temperature of the web base, separate from the temperature of the fastener, to help maintain the desired shape of the fastener as the web stretches. The liquid bath can be configured such that the fastener product is either suspended in the liquid or supported by the lower surface of the liquid bath. In the arrangement of Figure 26, the entire fastener product (ie web base 10 and fastener 11) is submerged in a temperature controlled fluid (either bath liquid or furnace air) to control the temperature of the product while stretching. Useful bath liquids include ethylene glycol.

An aspect of the present invention is the discovery that the tension effect between the substrate and the fastener is controllable, does not impede the stretching of products with discrete small fastener elements, and in fact, can be exploited in some cases to make the fastener achieve the desired desired shortening or geometry change.

The above-described embodiments relate to a fastener having a single resin component from which the fastener 11 and the base 12 are integrally formed. Other configurations can also take advantage of the invention and in some cases result in further improvements.

13, the forming system is as shown in FIG. 1 but with the addition of a wide roll 17 which is used to pull the preformed web 19 from a source not shown and feed it to the lower roll 16 before the nip. Materials 19 include pre-compressed woven products such as the so-called microcreping process of Walpole Micrex, Massachusetts. The braid is adapted to engage hooks formed by the device and is capable of stretching widthwise without shortening longitudinally. It is introduced to the surface of roll 16 in front of the nip and bonds to resin 20 according to the principles disclosed in US Patent No. 5,260,015, incorporated herein by reference. The resulting material is shown enlarged in Figure 13a. The hook element 11 is integral with the base web 12 as previously described, but the underside of the web is mixed with the fibers of a dense braid 19 and tightly joined to form an integral product. In one example, the braided product 19 is formed of fibers having a higher melting point and glass transition temperature than the resin forming the connecting strip 12 and the hook member 11, so that the braided fabric is easily heated by the preheater 32 of FIGS. 1 and 2. It maintains its ring structure under certain conditions. Therefore, when the air flow of the hot air source 34 of FIG. 2 penetrates the porous braid and contacts the resin, the braid structure as it is, actually acts as a heat sink, ensuring heat transfer to the connecting belt 12, and when the product reaches the system Stretchability is formed when the stretch zone of the

In this way a product with a contact tie hook on one side and a contact loop on the other is produced having a finished width significantly greater than the width of the product as it exits the molding roll 14 .

Referring to Figure 14, another embodiment utilizes the mounted rollers shown in Figures 1 and 2 . However, extruder 13a is a compound extruder, producing resin 21 and 23 streams of different properties. Streams 21 and 23 merge before reaching the extruder exit, and the combined extrudate 20a is fed as a layered composite of the two resins into the nip of the molding and pressure rolls. Resin 23 may have a smaller thickness than web 21, resin 23 being selected to primarily form fastener 11 while resin 21 primarily forms web 12'. Some advantages are gained in the latter stretching process by using mutually compatible resins with different rheological properties. For example, resin 23 is preferably selected to have a higher melting point and glass transition temperature than resin 21. Thus in the molded product, the fastener 11' at least partly includes the resin 23, making it less soft and less sensitive to the thermal deformation of the preheater 32, and therefore when subjected to sufficient heat so that the resin 21 of the connecting tape When easily stretched, they retain their shape more accurately. Another advantage of the Fig. 14 solution and product is that the resin 23 (Fig. 14a) of the hook 11' can be selected according to the peel and shear strength of the fastener 11', while the resin 21 of the base web 10' can be selected according to the optimal base web. Properties such as stretchability and fit are selected.

The system shown in Figure 15 comprises two molding rolls 14 and 14a with a nip into which resin is introduced from an extruder 18 as arranged in Figures 1 and 2 . However, two additional extruders 18a and 18b are provided to fill the molding cavities of the respective rolls 14a and 14 with resin. In the case where rolls 23 and 25 are provided, the auxiliary nip may be formed by respective molding rolls, introducing resin from auxiliary extruders 18a and 18b. At this point, the gaps of rolls 23 and 25 relative to their respective molding rolls are minimized so that a major portion of the resin enters the molding cavity. In addition, a scraper blade may be provided to push the resin into the molding cavity without leaving the resin constituting the base connection band at the periphery. The finished product has the fastening element 11 on one side and other elements, such as the fastening element 11', protruding from the opposite side. The resin selected to be extruded from the auxiliary extruders 18a and 18b can be similar to the resin 23 used in FIG. The webs of base resin formed by extruder 18 retain their shape and integrity when heated and stretched. A product made from the process equipment illustrated in FIG. 15 is shown in FIG. 15a, wherein the base web 10' is formed from one resin, the upper fastener 11 is formed from a second resin, and the lower fastener 11' is formed from a third resin. .

As shown in Figure 16, a radiant preheater 32a may be utilized wherein radiant elements 35 direct radiant energy to the product 10 to bring it into a stretchable state. The advantage is that the resin provided by the auxiliary extruders 18a and 18b can be of reflective or colored pigment, which limits the amount of radiation absorbed by the projections 11 and 11', so the resin provided by the extruder 18 can be black, for example or other strong absorbers of radiant energy. (The resin forming the fastener 11' provided in Fig. 14 plays a similar role). It may be desirable in certain instances to select the resin of extruder 18a to have properties different from those of extruder 18b. For example, in the case where the resin from extruder 18a solidifies faster than the resin from 18b and separates more easily from its molding rolls in the nip, the resin from extruder 18b travels with roll 14 toward peel roll 22a. Medium has a longer cooling time.

In all of the above implementations a preheater is described, while another implementation in an in-line setup has transverse stretching close to the molding rolls 14 and receives the product 10 in a soft stretchable state directly from the temperature controlled rolls. At this time, the heat of the extrusion and forming process is used to supply the connection belt in a stretchable state to enable the transverse stretching device 40 to function. In this connection, it should be noted that the protruding fastener 11 has a large exposed surface area relative to its volume and, under suitable conditions, cools faster than the base connection strip 12, and thus is less susceptible to stress during stretching than the base connection. The strap itself is stronger and more resistant to deformation, which is desirable in most situations.

As shown in Figure 17, in another embodiment an additional material is laminated to the opposite web side of the fastener element of the stretched product. After leaving the stretch stand 40, the backside of the web 99 of the product is in a heat-softened state, and the additional material 100 from the roll source 102 is connected with the web as it passes over the lamination roll 104 before being wound on the take-up roll 106. with backside contact. In the illustrated embodiment, the web 99 under tension is drawn along the arc of lamination rollers which apply pressure between the web 99 and the additional material. The softened web 99 is permanently bonded to the additional material 100 applied by the lamination roll to form a two sided product 108 up to several feet wide with the fastener on one side and the additional material on the other.

In one embodiment, the additional material is a wall covering to which hooks are added for securing the wall covering to the wall.

In another example where a floor ply is manufactured, such as for an automobile, the additional material includes a fiber mat on top and molded tie hooks underneath to secure the floor ply to the permanent floor covering of the automobile.

In another example, a field carpet is formed with the additional rows forming the top surface of the carpet and the connecting strips forming the fasteners to secure it to the permanent floor.

To manufacture all of these products, in certain instances, a further step is used to achieve bonding between the additional material and the connecting strip with the fastener. For example, in one example (FIG. 18) adhesive 110 may be applied to the additional material (and/or to the web) prior to lamination to the web. In another version (FIG. 19), the web and (in some cases actually flame-set) the additional material are laminated with flame softening of the add-on material (and/or webbing) prior to lamination. Yet in another example (FIG. 20), air jets 112 help compress the two layers of the laminate together against the lamination rolls to aid interlayer bonding. Combinations of these bonding-enhancing techniques are also useful.

Several products demonstrated the practicality of the invention. Some examples are now given.

In the first example, a stream of 12 polypropylene with a glass transition temperature near room temperature was molded on a 0.012-inch thick, 12-inch wide web with an overall height of about 0.035 inches and an areal density of 750 hooks per square inch Fasteners. Batches of molded product were drawn to final widths of 3, 4, 5, and 6 feet and made to thicknesses of 0.005, 0.004, 0.003, and 0.002 inches. Little or no deformation occurs during stretching.

In another example, the portion is a polypropylene flow molded to a height of 0.028 inches with an areal density of 900 hooks per square inch. The tear resistant structure is molded with the fasteners on the webbing approximately 0.005 inches thick. The product widths were stretched to ratios of 3:1 and 4:1 and the thicknesses were reduced to 0.0015 and 0.001 inches. It should be noted that the greater the stretching ratio, the more uniform the thickness of the final webbing product. There is also little or no deformation during stretching to produce a usable lashing tape 30-40 inches wide.

The same product as in the above example, after being stretched twice its width on the stretching frame, is trimmed to the original width and stretched longitudinally 2:1 by the stretching frame. The resulting web is about 0.001 inches thick, and the spacing between fastener elements is doubled both widthwise and longitudinally.

A 12 inch nylon 6/6 fastener tape was fabricated by drawing a 6 inch wide connecting tape having an areal density of about 147 hooks per square inch, a hook height of 0.100 inches.

A bottle grade of ethylene terephthalate polyester with a glass transition temperature of 150F was used in the same apparatus as in the nylon example above and stretched four times its molded width to produce a A very flexible fastening product, four feet wide, with a webbing thickness of only 0.001 inches.

Low density polypropylene with a glass transition temperature well below room temperature was molded into 0.008 inch thick by 12 inch wide connector strips with 0.35 inch high hook-shaped fasteners at an original areal density of 750 hooks/square inch. Attempts to stretch the product to a final width of 4 feet resulted in localized tearing and a reduction in hook height. Usable products were produced in stretched widths of 2 and 3 feet with little or no hook deformation and web thicknesses of 0.004 and 0.003 inches.

Claims (46)

1. method of making thin slice shape fastener product comprises:

Making the connecting band substrate have under the condition of molecular structure of vertical preorientation the mouldable resin flake of longitudinal stretching (20);

With a roational molding roller (14) from the molded continuous connecting band (10) of described thin slice with a substrate (12) and some discrete fasteners (11) that stretch out from least one side of substrate;

Then, but under the state of connecting band permanent elongation, cross directional stretch connecting band (10) makes permanent elongation substrate (12), and increases fastener (11) lateral separation (W ₁).

2. method according to claim 1 is characterized in that, fastener comprises the solid hook of contact system.

3. method according to claim 1 is characterized in that, stretching increases the horizontal molecularly oriented and the peel strength of fastener product.

4. method according to claim 1 is characterized in that, the width of the product of width tension (W) is about 2: 1 to 10: 1 with the width ratio of the preceding product that stretches.

5. method according to claim 1 is characterized in that, width tension relates to and reduces at least 50% with the substrate of connecting band is thick.

6. method according to claim 1 is characterized in that width tension makes connecting band widen at least 200%, and reduces the thickness (t of connecting band substrate (12) between the fastener (11) ₀) 2/3.

7. method according to claim 1 is characterized in that, comprises also that heating connecting band (10) makes connecting band (10) substrate (12) but permanent elongation and do not make the shape of fastener (11) that harmful the variation taken place.

8. method according to claim 7 is characterized in that, fastener (11) only stretches out from a side of connecting band (10), and connecting band is from reverse side (S) heating of the side of stretching out fastener.

9. method according to claim 1 is characterized in that, resin is from by the thermoplastic resin of selecting the following group that constitutes: polypropylene, polyethylene, polyester, polystyrene, PVC, nylon or their copolymer or polymeric blends.

10. method according to claim 1 is characterized in that, cross directional stretch makes connecting band (10) substrate (12) molecularly oriented and reinforcement between fastener (11), and the whole connecting band substrate of its result between fastener be width tension as one man.

11. method according to claim 10, it is characterized in that, described synthetic resin has distinctive minimum stretch rate, described mold roll is connecting restriction stretching structure (90) figure that forms on the zone face, selects connecting band width before connecting band width (W) that figure keeps width tension and the width tension than less than distinctive minimum stretch rate.

12. method according to claim 11, it is characterized in that, restriction stretching structure (90) is to be formed by resin flake (20), and method comprises the step that differentially heats molded connecting band (10), so that the structure (90) that restriction stretches can stretch than connecting band substrate (12) lessly.

13. method according to claim 11 is characterized in that, the structure (90) that restriction stretches comprises molded fastener (11).

14. method according to claim 1 is characterized in that, resin is from by selecting the following group that constitutes: terephthalic acid (TPA) polyglycol ester, polypropylene and their copolymer.

15. method according to claim 1 is characterized in that, resin comprises again with the terephthalic acid (TPA) polyglycol ester (PET) of making the bottle grade.

16. method according to claim 1 is characterized in that, control connecting band substrate (12) temperature when being included in connecting band (10) width tension.

17. method according to claim 16 is characterized in that, when being included in width tension fastener (11) is immersed in the temperature control fluid.

18. method according to claim 16 is characterized in that, when being included in width tension connecting band substrate (10) is immersed in the temperature control fluid.

19. method according to claim 16 is characterized in that, heating connecting band substrate (12) in the bath of liquid of heating when being included in width tension, and fastener (11) is exposed in the air simultaneously.

20. method according to claim 1 is characterized in that, the step of width tension connecting band comprises,

At the first stretch zones (Z ₁) width tension connecting band (10);

Connecting band is remained on middle stretched width; And then

At the second stretch zones (Z ₂) further width tension connecting band.

21. method according to claim 20 is characterized in that, width tension speed is along the first stretch zones (Z ₁) change.

22. method according to claim 1, it is characterized in that, fastener when molded (11) basic side is to vertically (T), and width tension is included in incline direction stretching connecting band (10), make fastener (11) towards with the vertical incline direction of (T) angled (α).

23. method according to claim 1 is characterized in that, also be included in cross directional stretch after, additional materials (100) is attached on opposite connecting band substrate (12) side of fastener (11).

24. method according to claim 23 is characterized in that, described combination is included under connecting band substrate (12) the thermal softening condition to be passed through additional materials (100) and connecting band (10) on a roller (104).

25. method according to claim 23 is characterized in that, described combination comprises to additional materials (100) and connecting band substrate (12) and applies bond (110) at least one, then with additional materials and connecting band in conjunction with forming lamination (108).

26. method according to claim 23, it is characterized in that, described combination comprises the surface of one of thermal softening additional materials (100) and connecting band substrate (12), and then additional materials and connecting band is gone up by the connecting band substrate is attached on the additional materials at a roller (104).

27. method according to claim 1 is characterized in that, described longitudinal stretching is by soften resin thin slice (20), then softening resin flake is pulled in the roll gap between mold roll (14) and pressure roll (16).

28. method according to claim 1 is characterized in that, keeps the longitudinal separation of molded fastener (11) when described width tension.

29. a fastener product is made of synthetic resin, have along a continuous connecting band substrate (12) extend and with the molded fastener of many rows (11) of its one, the connecting band substrate between the fastener row has:

As stretching result before fastener (11) is molded at first direction to a certain degree molecularly oriented,

As the molecularly oriented to a certain degree on the second direction vertical with first direction in the molded back of fastener (11) permanent elongation result.

30. product according to claim 29 is characterized in that fastener comprises hook member, its profile tilts with respect to the continuous length of connecting band.

31. product according to claim 29 is characterized in that, the thickness (t of described connecting band substrate between fastener (11) row ₁) approximately less than 0.08 millimeter.

32. product according to claim 29 is characterized in that, the width that has (W) is 2.4 meters at least.

33. product according to claim 29 laterally has enough molecularly oriented formation tear resistance in the vertical.

34. product according to claim 29 is characterized in that, is formed on transversely tear resistance vertically having enough molecularly oriented.

35. product according to claim 29 is characterized in that, resin is from by selecting the following group that constitutes: terephthalic acid (TPA) polyglycol ester, polypropylene and their copolymer.

36. product according to claim 29 is characterized in that, is formed by following process

Supply synthetic resin (20) continuously to roational molding roller (14);

Synthetic resin is molded as the prefabricated component (10) of continuous length, and it has with the fastener of the molded one of prefabricated component substrate arranges, and fastener is arranged and limited

In the continuous longitudinal length of prefabricated component between adjacent fastener molded longitudinal separation (L ₀),

On the heavy mutually direction of the continuous longitudinal length of prefabricated component between adjacent fastener molded lateral separation (t ₀);

In the cross directional stretch prefabricated component substrate of prefabricated component continuous length, thereby the lateral separation of the arrangement of increase fastener is (as arriving t ₁), the longitudinal separation that keeps the fastener arrangement simultaneously is substantially at molded longitudinal separation (L ₀), consequently the connecting band substrate (12) at molded back product only is in laterally permanent elongation state.

37. product according to claim 36 is characterized in that, the synthetic resin (20) of supplying with mold roll (14) at resin supply to having to a certain degree molecularly oriented.

38., it is characterized in that synthetic resin is subjected to overstretching before molded according to the described product of claim 37.

39. a decorative layer (108) is characterized in that, comprises that the described product of claim 29 and is the sheeting of lamination, the fastener of product (11) constitutes the device that described layer is fixed on the desired location.

40. according to the described decorative layer of claim 39, it is characterized in that, can cover wall and floor.

41. one kind forms a kind of is the device of solid product, comprises

The roller of a pair of formation roll gap (14,16), wherein at least one roller is a mold roll, formation is the fastener (11) that one is stretched out with the continuous length side surface of connecting band substrate (12);

To the device (18) of roll gap for plastic resin (20), thereby resin is subjected to vertical the stretching before molded; With

One cross directional stretch device (40) is in the connecting band substrate (12) of the described roller of cross directional stretch to making of the continuous length of described connecting band substrate.

42. according to the described device of claim 41, it is characterized in that, comprise that adds a heat tunnel (32), connecting band substrate (12) arrives described stretching device (40) before by it, adds the opposing face (S) of the connecting band substrate of heat tunnel heating fastener (11) side, place.

43. according to the described device of claim 41, it is characterized in that, comprise a squeezer (18) for the device of plastic resin, the resin of confession (20) by roller to (14,16) the tension force longitudinal stretching of Chan Shenging made before the substrate of shaping connecting band at machine direction resinous molecular structure generation preorientation.

44., it is characterized in that according to the described device of claim 41, comprise a squeezer that can be arranged on the roll gap for the device of plastic resin, the resin of confession by inertia force between squeezer and roll gap to the small part longitudinal stretching.

45. according to the described device of claim 41, it is characterized in that, comprise the suprabasil device of connecting band that additional materials (100) is laminated to stretching.

46., it is characterized in that the device of lamination additional materials comprises a roller (104) according to the described device of claim 45, described product drags around it in extended state.

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