JP3710143B2 - Storage case for recording medium and method of manufacturing raw sheet for storage case by extrusion molding - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to a storage case for a recording medium and a method for manufacturing the storage case sheet by extrusion molding.
[0002]
[Prior art]
The storage case (Fig. 1) used as a videocassette protective case is generally made of polypropylene as well as paper. This polypropylene is melted from a pellet and extruded from a raw material tank, and then rolled into a single layer with a rolling roll. And finished to a uniform thickness to obtain a raw material cut into a predetermined dimension. Then, in a separate process, the blanks are punched into dimensions, and the final shape is finished by adding a brace that becomes a bent portion during box making.
In general, display of contents, processing of trademarks, product numbers, other information, designs, and the like are performed on the outer surface of the storage case during the extrusion process or in another process thereafter.
[0003]
[Problems to be solved by the invention]
Here, if the conventional example of main processing methods, such as a design, is given, as shown in FIG. 2, a predetermined design is printed on a single-layer sheet original fabric, and a printing film is applied to the single-layer sheet original fabric. There are [Type II] for laminating and [Type III] for forming a design by engraving on the original single layer sheet during extrusion.
[0004]
However, such treatment methods have the following disadvantages.
In Type I, a printing process is required separately from the extrusion process in order to print the design, leading to an increase in cost. Further, since the original fabric is moved, scratches and deformations are likely to occur, and if the print layer is scratched or deformed, it is a fatal product because it is a thin layer. And since it is a plane design, the three-dimensional effect of the thickness direction cannot be expressed.
In Type II, the printing film is laminated in the extrusion process. However, there are variations in the production of the film itself and in the printing process (printing / drying), and the design accuracy is distorted due to shrinkage of the polypropylene in the lamination stage. easy. Moreover, since it is a plane design like Type I, it cannot express a three-dimensional effect in the thickness direction.
In Type III, a predetermined design can be applied in the extrusion process, but the design is difficult to see if the sheet original is transparent. For this reason, an opaque material is used, but the design characteristics are degraded because the surface is easily scratched during the manufacturing process.
[0005]
Therefore, the present invention solves these drawbacks (i.e., 1. does not lead to an increase in cost, 2. eliminates movement of the original fabric, 3. provides a three-dimensional effect in the thickness direction, and 4. type. Providing a manufacturing method including a design processing method and a storage case manufactured by using this manufacturing method (which solves the fact that II variation and design accuracy do not occur, and 5. prevents the deterioration of the design characteristics) To do.
[0006]
[Means for Solving the Problems]
The sheet for storage case according to the present invention comprises a two-layer laminated sheet formed by extrusion molding, and a design process is applied to the lower layer sheet using a pair of upper and lower first rolls (engraving rolls) at the stage before lamination. Then, an upper layer sheet made of a transparent or translucent material is superimposed on the upper surface of the lower layer sheet and passed through a pair of upper and lower second rolls. After passing, the upper and lower layer sheets are bonded to obtain a laminated sheet, and then cut into a laminated sheet original fabric having a predetermined dimension.
Thereafter, in a separate process, the blanks are punched into a predetermined shape, folded into the shape of a storage case, and bonded or fused with overlapping side pieces to obtain a desired storage case.
[0007]
Since only the extrusion process is performed until the laminated sheet original fabric is obtained after finishing the design process, there is no need for a separate process such as a printing process, preventing an increase in cost, and there is no need to move the original fabric. In addition, since there is no connection with the printing film or the printing process, there is no variation and no deviation in design accuracy. In addition, the design of the lower layer sheet by engraving is adhesively protected with a transparent (or translucent) upper layer sheet to prevent deterioration of the design characteristics while maintaining the three-dimensional effect in the thickness direction. Thus, the above five drawbacks are eliminated.
[0008]
【Example】
FIG. 3 is a schematic view of the manufacturing apparatus 1 (or the flow of the manufacturing method) of the laminated sheet original fabric 13 for forming the video cassette storage case by extrusion molding. The manufacturing apparatus 1 includes first and second raw material tanks 2 and 8 that mainly contain molten plastics 14 and 15 such as polypropylene (the molten plastic 15 is transparent or translucent), respectively, and the plastics 14 and 15. A pair of rolls 3 and 9 for rolling the sheet 4 to a sheet 4 and 10 having a predetermined thickness, respectively, and a first sheet for obtaining a lower layer sheet 7 by applying a desired design to the sheet 4 rolled from the pair of rolls 3. An upper roll 5 and a first lower roll 6, a transparent (or translucent) upper layer sheet 10 rolled from a pair of rolls 9 and a lower layer sheet 7 with a design are laminated to obtain a sheet 18. Two upper rolls 11 and a second lower roll 12, and a die 16 for cutting the laminated sheet 18 into a predetermined size to obtain a laminated sheet original fabric 13.
Alternatively, the first upper and lower rolls 5 and 6 may be configured to perform the function of the pair of rolls 3.
[0009]
The colored polypropylene material 14 extruded from the raw material tank 2 is rolled into a sheet 4 having a predetermined thickness by a pair of rolls 3 and then passed between the first upper roll 5 and the first lower roll 6. The lower layer sheet 7 coming out of the upper and lower first rolls is subjected to a desired design treatment (a design by changing one of the upper and lower first rolls as appropriate, or by design or combination of design, satin, or punching). Sent to two rolls 11 and 12. FIG. 4 shows the state of the lower layer sheet 7 coming out from the upper and lower first rolls 5 and 6. The lower layer sheet 7 is the same as the type III in the conventional example if it is a commercial product as it is, but the following processing is further performed in the present invention.
[0010]
The transparent (or translucent) polypropylene material 15 extruded from the raw material tank 8 is rolled into a transparent (or translucent) upper layer sheet 10 having a predetermined thickness by a pair of rolls 9, and then the second upper roll 11 and It is sent between the second lower rolls 12. At this time, the transparent (or translucent) upper layer sheet 10 coming out of the pair of rolling rolls 9 is overlapped with the lower layer sheet 7 sent from the first rolls 5 and 6, and between the upper and lower second rolls 11 and 12. Is rolled and bonded. At this stage, an additional design may be applied to the upper part of the transparent (or translucent) upper layer sheet 10. When coming out of the upper and lower second rolls 11 and 12, a laminated sheet 18 is obtained. The upper and lower first rolls and the upper and lower second rolls can be combined by appropriately selecting rolls of the same or different designs and dimensions.
As described above, the present invention is completely different from the injection molding. Therefore, the lower layer sheet 7 is not melted, crushed or flowed by the upper layer sheet 10 during the lamination in the injection molding, and the lamination can be molded while maintaining a good design. (In injection molding, the injection pressure is high and the resin is completely melted, whereas in extrusion molding, the injection pressure is low and the resin is also semi-molten).
Then, the raw materials of the upper and lower layer sheets may be the same or different, and their color tone may be the same or different (although the upper layer is transparent or translucent in this embodiment). Moreover, you may add aluminum powder, a calcium carbonate, etc. to the raw material of the sheet | seat of an upper-lower layer.
[0011]
The manufactured laminated sheet 18 is cut by the punching die 16 to obtain a laminated sheet original fabric 13 having a predetermined size. After that, in a separate process, it is punched into the shape of a predetermined blank 17 as shown in FIG. 5 (a), folded into the shape of the storage case 30 as shown in FIG. 5 (d), and bonded or fused with the overlapping side piece. To obtain the desired storage case.
[0012]
In an example of the storage case of the present invention by the above manufacturing method, FIGS. 5B and 5C are cross-sectional views taken along the line AA in FIG. This original laminated sheet 13 is composed of an upper sheet 10 having a small recess 32 as an additional design and a lower layer sheet 7 having a large recess 34 indicating a design. The boundary surface between the upper layer sheet 10 and the lower layer sheet 7 may be provided with irregularities (not shown) smaller than the small concave portions 32 in order to increase the adhesive strength.
As another example, the upper sheet 10 may be provided with a through-hole 33 by the convex portion of the second upper roll 11 to form a laminated sheet original fabric 13 ′ as shown in FIG. 5C, or as shown in FIG. It is good also as the sheet | seat original fabric 13 "which provided the convex-shaped design 35 in the lower layer sheet 7 contrary to the said recessed part 34, and laminated | stacked the upper layer sheet | seat 10 on this. The laminated sheet original fabric 13 of FIG.5 (c) is good. It is preferable that the through portion 33 of 'is filled with the same material as that of the lower layer sheet 7.
[0013]
【The invention's effect】
Since only the extrusion process is performed until the laminated sheet original fabric is obtained after finishing the design process, there is no need for a separate process such as a printing process, preventing an increase in cost, and there is no need to move the original fabric. In addition, since there is no printing film or printing process, variations and design accuracy are prevented from occurring. In addition, the design of the lower layer sheet by engraving is adhesively protected with a transparent (or translucent) upper layer sheet, thereby making it possible to prevent deterioration in design characteristics for a long time while maintaining the three-dimensional effect in the thickness direction.
Various designs can be expressed by combining the shape (design) of the first and second rolls and the material (transparent, translucent, opaque coloring).
In addition, the simple two-layer sheet is basically composed of the same material due to the problem of adhesive strength. However, in the present invention, the selection of material grade (changes physical properties with polypropylene) and improvement of design properties (additives such as flakes and aluminum powder) Etc.) became possible.
[0014]
While the presently preferred embodiment of the invention has been illustrated and described, it would be obvious to those skilled in the art that various changes and modifications can be made without departing from the spirit of the invention. . All such changes and modifications should be included in the technical idea of the present invention.
[Brief description of the drawings]
FIG. 1 is a perspective view of a storage case for a conventional general video cassette.
FIG. 2 is a cross-sectional view of a conventional original sheet.
FIG. 3 is an overall schematic view of a sheet original fabric manufacturing apparatus according to the present invention.
FIG. 4 is a cross-sectional view of a lower layer sheet according to the present invention.
5A is a plan view of a blank according to the present invention, FIGS. 5B and 5C are cross-sectional views taken along line AA in FIG. 5A, and FIG. 5D is an assembly of the blank of FIG. FIG.
6A is a plan view of a blank according to the present invention, FIG. 6B is a sectional view taken along line AA in FIG. 6A, and FIG. 6C is an assembly view of the blank of FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Sheet raw fabric manufacturing apparatus 2, 8 Raw material tank 3 First rolling roll 4 Sheet 5 First upper roll 6 First lower roll 7 Lower layer sheet 9 Second rolling roll 10 Upper layer 11 Second upper roll 12 Second lower roll 13, 13 ′, 13 ″ Laminated sheet raw fabric 14, 15 Raw material 16 Punching die 17, 17 ′ Blanks 18 Laminated sheet 30, 30 ′ Storage case 32 Additional design 33 Through hole 34 Concave design 35 Convex design

Claims (7)

  In a method for producing a laminated sheet original made of an upper layer sheet and a lower layer sheet by extrusion molding, the first pair of rolling rolls (3) has a predetermined thickness of a first molten plastic such as polypropylene extruded from the first raw material tank. A first upper roll (5) that is rolled to a sheet of the predetermined thickness and pressure-bonded to the surface to be bonded to the upper layer sheet of the predetermined thickness and the surface of the original laminated sheet of the predetermined thickness sheet By passing the sheet having the predetermined thickness between the first lower roll (6) to be pressure-bonded to the surface on the other side, the engraving of the first upper roll is designed on the sheet having the predetermined thickness. A first step of obtaining a desired lower layer sheet, a second pair of rolling rolls (9) rolling a second molten plastic such as polypropylene extruded from the second raw material tank into a sheet having a predetermined thickness, Second A roll (11) and a second lower roll (12) are laminated by laminating the upper layer sheet rolled from the second pair of rolling rolls (9) and the lower layer sheet obtained by the first step. A method for producing a laminated sheet original fabric, comprising: a second stage to be obtained; and a third stage in which a punching die is cut from the laminated sheet fed from the second stage into a laminated sheet original fabric having a predetermined size.   The manufacturing method of the laminated sheet original fabric of Claim 1 with which said 2nd upper roll is provided with engraving.   The method for producing an original laminated sheet according to claim 1 or 2, wherein the molten plastic such as polypropylene contained in the second raw material tank is transparent or translucent. 3. A storage case for a recording medium, which is assembled after blanking a sheet raw material laminated by the manufacturing method according to claim 2, wherein a small concave portion or a through hole serving as a design portion is formed on the inner upper layer sheet of the upper and lower laminated sheets. The storage case for a recording medium, wherein a hole is provided.   3. A storage case for a recording medium, which is assembled after blanking a sheet raw material laminated by the manufacturing method according to claim 1 or 2, wherein a concave or convex shape is formed on the lower layer sheet at an adhesive boundary surface of the upper and lower laminated sheets. A storage case for a recording medium, wherein the design portion is provided with a step.   The storage case for a recording medium according to claim 5, wherein the upper layer sheet is made of a transparent or translucent material.   The storage case for a recording medium according to claim 4, 5 or 6, wherein small irregularities are formed on a boundary surface between the upper layer and the lower layer sheet in order to increase adhesive strength.

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