JP2002036387A - Rule applied plastic sheet, method for manufacturing the same and molded article using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a plastic sheet excellent in one-action operation properties at the time of restoration from a folded state and a method for efficiently manufacturing the same. SOLUTION: The plastic sheet has the rule for bending so that the cross-sectional shape in the direction right-angled to the rule forms a projected part in the direction opposite to the rule. This plastic sheet can be manufactured by laying a plastic plate with a Rockwell hardness of 30-120 (R scale) under the plastic sheet and the length of a cutting blade is set so as to be same to or shorter than a press rule to apply the rule simultaneously with cutting.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ruled plastic sheet, a method for producing the same, and a molded product using the same. More specifically, the present invention relates to a ruled plastic sheet having a cross section in a direction perpendicular to the ruled line and having a projection formed in a direction opposite to the ruled line, so that assembly is easy.

[0002]

The plastic case is provided with a ruled line in a plastic sheet and punched out into a predetermined shape, and then bent along the ruled line, glued and fixed at a necessary portion, and then produced. However, in order to be bulky at the time of shipping, it is folded along a ruled line and shipped in a flat shape. When it is ready for use at the point of shipment, it must be returned from its planar state to its original box-like shape. At that time, it often does not easily return to the original shape.

[0003] For example, the bottom surface to be formed into a rectangular shape becomes distorted, or the side surface which should rise at a right angle from the bottom surface rises at an acute or obtuse angle. Alternatively, there is a problem that it takes time and effort to be restored.

[0004] Such problems not only affect the quality of the product, but also lower the productivity and increase the cost. Therefore, what can be restored to the original shape with one touch is most desirable.

In order to improve such one-touch performance,
Many suggestions have been made. For example, it has been proposed to draw ruled lines in perforations. However, although the one-touch property of the ruled sheet obtained by this method is improved,
There is a disadvantage that the tear strength and the repeated bending strength are extremely reduced.

Further, attempts have been made to increase the depth of the ruled line in order to improve the one-touch property (that is, to reduce the minimum thickness of the cross section), but the contact between the punching blade and the receiving plate during the punching process has been attempted. Is too strong, so that not only the life of the blade is extremely shortened, but also the number of defective products due to cutting at the sheet crease portion due to the crease of the crease blade is increased, and productivity is remarkably reduced. That is, merely changing the depth of the ruled line has a problem that the one-touch property is inferior or the productivity is reduced, and it has been difficult to find an optimum point.

[0007]

The inventor of the present invention has made intensive studies to solve the above-mentioned problems without lowering other physical properties, and as a result, has reached the present invention. That is, the present inventor focused on the shape of the ruled line and observed the shape of a commercially available plastic sheet. As shown in FIG. 4, the cross-sectional shape perpendicular to the ruled line formed a recess in the direction opposite to the ruled line. I understand that you are doing. Therefore, when the cross-sectional shape is changed to the shape shown in FIG. 1 or FIG. 3, that is, the cross-sectional shape in the direction perpendicular to the ruled line forms a convex portion in the direction opposite to the ruled line, the above-described problem is solved. The present invention has been found that it is possible.

Further, there are various problems when manufacturing a plastic sheet having convex portions formed in the direction opposite to the ruled line according to the present invention, not only in the case of one-piece production but also in the case of industrial production.

Normally, when making a plastic sheet with a ruled line using an automatic flat plate punching machine, as shown in an enlarged view of the punched portion in FIG. 11, the cutting blade is longer than the ruled sheet and the sheet is punched. Insert a ruled line. However, the sheet of the present invention having a convex portion on the side opposite to the ruled line cannot be obtained.

In view of this, for example, as shown in FIG. 12, it is conceivable to install a ruled line convex portion receiver in which a concave portion corresponding to a convex portion is newly dug on a receiving plate. However, in this method, there is a problem that a new ruled line projection receiver is required every time the depth of the ruled line, the shape of the case to be created, the number of impositions, and the like change. In addition, a method of directly digging a concave portion corresponding to the convex portion in the receiving plate can be considered, but this naturally has the same disadvantage.

As a result, as a method for efficiently producing the plastic sheet of the present invention, a plastic plate having specific physical properties is sandwiched between the sheet and the receiving plate, and the length of the rule is the same as or shorter than that of the cutting blade. It was found that the object of the present invention was achieved by punching after setting the length to be longer, and the production method of the present invention was reached. FIG. 13 shows a pattern for producing the sheet of the present invention by the manufacturing method of the present invention.

[0012]

The present invention comprises the following constitutions. (1) A plastic sheet having a ruled line and having a cross section perpendicular to the ruled line forming a convex portion in a direction opposite to the ruled line. (2) The maximum depth of the crease measured from the surface of the plastic sheet is 4 times the thickness of the sheet where no crease is formed.
The plastic sheet according to item (1), which is 0 to 110%. (3) The minimum thickness of the part where the ruled line is perforated is 30 to 80% of the thickness of the sheet of the part where the ruled line is not perforated.
Or the plastic sheet according to the above mode (2). (4) The plastic sheet according to (1) to (3), which is stamped. (5) When a cutting sheet and a ruled line (ruled line insertion blade) are pressed from above on a plastic sheet placed on a receiving plate to form a ruled lined plastic sheet of a predetermined shape,
A plastic plate having a Rockwell hardness (ASTM D-785) of 30 to 120 (R scale) is sandwiched between the receiving plate and the plastic sheet, and the length of the rule is the same as or longer than that of the cutting blade. A method for producing a plastic sheet with a ruled line, characterized by punching out. (6) The difference between the length of the ruled rule and the length of the cutting edge is 0 to 0.15 mm
(5). The method for producing a plastic sheet according to (5). (7) The method for producing a plastic sheet according to (5) or (6), wherein the thickness of the plastic plate is 1 to 5 mm. (8) The method for producing a plastic sheet according to any one of (5) to (7), wherein the plastic plate is any one of polyethylene, polypropylene, polystyrene, ABS, polyethylene terephthalate, and polyvinyl chloride resins. (9) A molded article using the plastic sheet according to the above (1) to (4). (10) A plastic case using the plastic sheet according to any one of (1) to (4). (11) A file using the plastic sheet according to any one of (1) to (4).

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Synthetic resins used in the plastic sheet of the present invention include polyolefin resins such as polyethylene, polypropylene, polybutene-1 and poly-4-methylpentene-1; atactic polystyrene;
Polystyrene resins such as syndiotactic polystyrene and ABS resin; polyester resins such as polyethylene terephthalate and polybutylene terephthalate; polyamide resins such as 6-nylon and 6,6-nylon; and thermoplastic resins such as vinyl chloride resin. Can be mentioned. These resins may be uncolored or colored resins.

[0014] Such a thermoplastic resin is formed into a sheet by a known method such as extrusion molding, the sheet is cut into a predetermined shape, and a ruled line is formed at a predetermined position to produce a plastic sheet. Alternatively, it is also possible to punch a predetermined shape at the same time as forming a ruled line. Alternatively, it is also possible to put a resin into a mold having a predetermined shape and perform melt molding.

Furthermore, the above-mentioned method of installing the ruled line convex portion receiver in order to form a shape having a convex portion on the side opposite to the ruled line of the present invention may be used, but for mass production economically, it will be described later. The production method of the present invention is preferred.

That is, as shown in FIG. 13, a plastic plate is sandwiched between a receiving plate provided at a lower portion and a plastic sheet to be punched placed thereon, and a cutting blade and a crease are pressed from above. Thus, the sheet is punched into a predetermined shape, and a ruled line is formed by pressing. After the punching, as shown at the bottom of FIG. 13, the plastic plate temporarily dented at the time of the punching is restored by its elasticity and is reused.

In this manner, the plastic sheet of the present invention having a cross section perpendicular to the ruled line as shown in FIG. 1 or 3 can be obtained.

The plastic plate used in the present invention has a Rockwell hardness (ASTM D-785) of 30 to 120.
(R scale) plastic. If the Rockwell hardness is less than 30, the force of pressing the sheet between the pressing rule and the plastic plate becomes weak, so that only a small ruled line is formed, which is not preferable. On the other hand, if it exceeds 120, the force for pressing the sheet between the press rule and the plastic plate becomes too strong, so that the thickness of the ruled line portion becomes too thin, which is not preferable.

As long as the Rockwell hardness falls within this range, either a thermoplastic resin or a thermosetting resin may be used, but a thermoplastic resin is preferred from the viewpoint of workability. As a specific example of such a resin, the resin used for the plastic sheet described above can be used. However, it goes without saying that any resin may be used as long as it is the resin described above. For example, the hardness of a polyvinyl chloride resin varies greatly depending on the presence or absence of a plasticizer and the type of stabilizer. The same applies to polystyrene resins depending on whether they are copolymers or homopolymers. The point is that the Rockwell hardness must be within the range described above.

The thickness of the plastic plate used in the present invention is preferably 1 to 5 mm. If it is less than 1 mm, the ruled sheet is difficult to be formed due to the influence of the steel plate, and if it is forcibly pressed, the ruled line tends to be cut off or the ruled line portion tends to be thin. Conversely, if it exceeds 5 mm, the absolute value of the thickness variation of the plate becomes large,
It becomes difficult to adjust so that the cutting blades reach the surface of the plastic plate at all points at the same time, and it becomes difficult to control the depth of the ruled line because the cushion becomes large.

As a cutting blade for punching a plastic sheet, a known cutting blade having a sharp tip can be used. Further, since the pressing rule is not intended for cutting, it is preferable that the tip is not sharp, and a known shape such as a semicircular or square cross section can be used.

The cutting blade and the crease are punched from the upper portion to the lower portion while holding the crease length equal to or longer than that of the cutting blade. It is preferable to keep the difference between the length of the creasing rule and that of the cutting blade at 0 to 0.15 mm, more preferably 0.05 to 0.10 mm. If it exceeds 0.15 mm, the convex portion formed on the opposite side of the ruled line becomes too large, and it may be difficult to bend to the opposite side of the ruled line. This is because there is a possibility that the sheet cannot be cut and cannot be cut.

FIGS. 5 and 6 show developed examples of the plastic sheet of the present invention. The sheet is bent along the ruled lines contained in the plastic sheet, and the mating surfaces are further adhered with an adhesive to form the plane shape for transportation shown in FIGS. 7 and 8.

This will be described in detail. In FIG. 5, by folding inward along the ruled lines 2 and 4 by 180 degrees, and bonding the outer mating surface of the ruled line 1 to the surface surrounded by the ruled lines 6, 4, and 7, The plane shape for transportation shown in FIG. 7 can be created.

On the other hand, in FIG. 6, first, it is bent inward by 180 degrees along the ruled line 16, and further bent inwardly by 180 degrees along the ruled lines 10 and 12. By being bent 180 degrees inward along the ruled line 13, the mating surface 20 is bonded to the surface surrounded by the ruled lines 15, 10, and 16 which are in contact with each other. Ruled lines 17 and 18 are both bent 180 degrees outward,
The mating surface 21 is bonded to the outside of the surface 23, and the mating surface 22 is bonded to the outside of the surface 24, respectively. Thereby, the shape of the plane for transportation shown in FIG. 8 can be created.

The shape shown in FIG. 7 can be formed by folding the ruled lines 1, 2, 3, 4 with one touch, and keeping the surfaces in contact with the ruled lines at right angles to each other. The upper and lower lids are closed by bending each of 5, 6, 7, and 8 inward at right angles to form the box shown in FIG. It is used in this form.

The shape shown in FIG. 8 can be formed by bending the ruled lines 1, 2, 3, and 4 with one touch and keeping the surfaces in contact with the ruled lines at right angles to each other. At this time, the lower lid has already been closed. Furthermore, the upper lid is closed by folding the ruled lines 15 and 14 inward by 90 degrees, and the box shown in FIG. 10 is formed and used in this shape.

In the present invention, together with the cross-sectional shape described above,
The depth of the ruled line and the thickness of the part where the ruled line is formed are also important. The former preferably has a maximum depth of 40 to 110% of the thickness of the sheet where the ruled line is not punched, and the latter has a minimum thickness of the sheet thickness of the portion where the ruled line is not punched. The case where it is 30 to 80% is preferable. Such one-touch property can be applied to other molded products having similar structures having different uses, and can be applied to, for example, files.

[0029]

EXAMPLES The effects of the present invention will be specifically described below with reference to examples and comparative examples. <Examples 1 and 2> and <Comparative Examples 1 and 2> A commercially available polyethylene terephthalate sheet (thickness: 0.3 mm) was punched into a predetermined shape by a punching machine equipped with a ruler blade, and a ruled line having a different cross-sectional shape was punched. Several kinds of laid plastic sheets were made. The tear strength, bending strength, and minimum thickness of the creases of the sheets were measured, and the cross-sectional shapes in the direction perpendicular to the creases were measured as shown in FIGS. 1 (Example 1), 2 (Comparative Example 1), and 3 (Example 2). ) And FIG. 4 (Comparative Example 2). Further, they were bent along the ruled lines, and the mating surfaces were adhered with an adhesive to produce a plastic case shown in FIG. 9 (Example 1 and Comparative Example 1) or FIG. 10 (Example 2 and Comparative Example 2). . As shown in FIG. 7 (Example 1 and Comparative Example 1) and FIG. 8 (Example 2 and Comparative Example 2),
After being kept for 0 days, the case was restored and the one-touch property was examined. The measurement results are shown in Table 1.

Comparing Example 1 with Comparative Example 1, the depth of the ruled line is about the same at about 0.25 mm, but in Comparative Example 1 where there is no bulge on the side opposite to the ruled line, the minimum thickness of the sheet is It is about 1/3 of Example 1, and the tear strength and bending strength are extremely weak. In addition, in the case of such a shape, there is a variation in the penetration of the ruled line blade during the punching operation, so that it is often pushed out, and the yield of the material is deteriorated. Therefore, even if the one-touch property is good, practicality is poor in terms of both physical properties and workability. According to these, the plastic sheet and the case (Examples 1 and 2) of the present invention in which the cross-sectional shape in the direction perpendicular to the ruled line is a plastic sheet in which the convex portion is formed in the direction opposite to the ruled line, the cross-sectional shape in the direction perpendicular to the ruled line Is a straight line in the direction opposite to the ruled line (Comparative Example 1), or any of the tear strength, bending strength and one-touch property as compared with the case where the commercial product is concave (Comparative Example 2). It can be understood that not only is excellent in one-touch, but also one-touch property is excellent in spite of a large cross-section minimum thickness.

[0031]

[Table 1]

<Examples 3 to 5> and <Comparative Examples 3 and 4> Next, using the manufacturing apparatus shown in FIG. 13, plastic sheets were manufactured under different manufacturing conditions, and the results are shown in Table 2. . Under the conditions of the present invention (Examples 3 to 5), the production situation was good, and a plastic sheet of the present invention having good characteristics was obtained. In Comparative Example 3, a plastic plate was manufactured under the same manufacturing conditions as in the example except that a resin having a small Rockwell hardness was used. However, since the plastic plate is soft, even if the pressing rule is pushed in as much as in the embodiment, the return after releasing the pressure is large, so that the ruled line is shallow and the height of the convex portion is small. In order to make the ruled line deeper, it is necessary to insert the cutting blade deeper than the contact point between the sheet and the plastic plate, so even the plastic plate is cut with the cutting blade, and if this is repeated, the cut surface becomes rough and goes further And poor cutting. On the contrary, Comparative Example 4 is a case where a resin having a large Rockwell hardness is used. In this case, under normal conditions, the cutting edge does not reach the contact point, resulting in poor cutting. If it is further pushed in from this state, it will be cut at the ruled line and stable production cannot be performed. In any case, no product is obtained.

[0033]

[Table 2]

[0034]

The plastic sheet of the present invention in which the cross section perpendicular to the ruled line forms a projection in the direction opposite to the ruled line is easy to process into a plastic case or files, and the obtained plastic case is also described above. It has good practical characteristics. Further, the production method of the present invention,
This makes it possible to easily manufacture such a plastic case.

[Brief description of the drawings]

FIG. 1 is a cross-sectional shape of a plastic sheet (Example 1) of the present invention in a direction perpendicular to a ruled line.

FIG. 2 is a cross-sectional shape of the plastic sheet shown in Comparative Example 1 in a direction perpendicular to a ruled line.

FIG. 3 is a cross-sectional shape of the plastic sheet of the present invention (Example 2) in a direction perpendicular to a ruled line.

FIG. 4 is a cross-sectional shape of the plastic sheet shown in Comparative Example 2 in a direction perpendicular to a ruled line.

FIG. 5 is a development view of the plastic sheet created in Example 1.

FIG. 6 is a development view of the plastic sheet created in Example 2.

FIG. 7 is a view showing a shape of the plastic case prepared in Example 1 and Comparative Example 1 folded for transportation.

FIG. 8 is a view showing a shape of a plastic case produced in Example 2 and Comparative Example 2 folded for transportation.

FIG. 9 is a perspective view of a plastic case created in Example 1 and Comparative Example 1.

FIG. 10 is a perspective view of a plastic case created in Example 2 and Comparative Example 2.

FIG. 11 is a schematic view of a method for manufacturing a ruled-lined plastic sheet which is usually performed.

FIG. 12 is a layout view of the apparatus when a press ruler is installed.

FIG. 13 is a schematic view of a method for producing a plastic sheet of the present invention.

[Explanation of symbols]

 1-18 ruled line 20-24 mating surface 31 punching die 32 cutting blade 33 pressing rule 34 sponge 35 plastic sheet 36 receiving plate 37 pressing rule receiving 38 plastic plate

Claims (11)

[Claims] 1. A plastic sheet having a ruled line, wherein a cross section in a direction perpendicular to the ruled line forms a convex portion in a direction opposite to the ruled line. 2. The plastic sheet according to claim 1, wherein the maximum depth of the crease measured from the surface of the plastic sheet is 40 to 110% of the thickness of the sheet where the crease is not formed. 3. The plastic sheet according to claim 1, wherein the minimum thickness of the portion where the ruled line is formed is 30 to 80% of the thickness of the sheet where the ruled line is not formed. 4. The plastic sheet according to claim 1, which has been punched. 5. When a cutting sheet and a ruled line (ruled line insertion blade) are pressed from above onto a plastic sheet placed on a receiving plate to form a ruled plastic sheet having a predetermined shape, the receiving plate and the plastic sheet may be combined with each other. It is characterized in that a plastic plate having a Rockwell hardness (ASTM D-785) of 30 to 120 (R scale) is sandwiched between them, and the length of the rule is the same as or longer than that of the cutting blade and punched out. Method for producing a ruled plastic sheet. 6. The difference between the length of the ruled rule and the length of the cutting edge is 0 to 6.
The method for producing a plastic sheet according to claim 5, wherein the thickness is 0.15 mm. 7. The method for producing a plastic sheet according to claim 5, wherein the thickness of the plastic plate is 1 to 5 mm. 8. The method for producing a plastic sheet according to claim 5, wherein the plastic plate is any one of a resin of polyethylene, polypropylene, polystyrene, ABS, polyethylene terephthalate or polyvinyl chloride. 9. A molded article using the plastic sheet according to claim 1. 10. A plastic case using the plastic sheet according to claim 1. 11. A file using the plastic sheet according to claim 1.