JP2000153562A - Plastic sheet having bent ruled line, its production and blade for bent ruled line - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a plastic sheet having bent ruled lines in which bending characteristics are good and a strain, a warpage and a surge, etc., are not caused at the time of working and realization of automation is contrived. SOLUTION: The bent ruled line 2 is provided with a pair of side parts 4, 5 which are tilted at a prescribed angle and mutually opposed and with a base part 3 continuing to one end side of the respective side parts 4, 5. Projection parts 6 are formed in the respective side parts 4, 5 in nearly equal intervals in the longitudinal directions of the side parts 4, 5 by a plurality of side ribs arranged in the range from one end side to the other end side continuing to the main face of a plastic sheet 1. In the bent ruled line 2, a plurality of projection parts 6 have a function reinforcing the side parts 4, 5. In the case of bending the base part 3, a stress is concentrated in the base part 3 and the bent ruled line 2 is bent in only the base part 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plastic sheet with a folded crease, a method for producing the same, and a folded crease blade.

[0002]

2. Description of the Related Art Conventionally, when a plastic sheet is bent to assemble a container for packaging or a case of goods, a groove-shaped concave portion is formed in a bent portion of the plastic sheet in order to perform accurate bending. (Hereinafter, referred to as a folding ruled line) is formed by pressing a ruled line blade, and bending is performed along the folding ruled line.

[0003]

A variety of shapes and structures have conventionally been used as folding ruled lines provided on a plastic sheet. As a structure of a conventional folding ruled line, for example, as shown in FIG. 7A, a groove having a substantially “U” cross section is provided from the main surface of the plastic sheet 1 or FIG.
A groove having a substantially W-shaped cross section as shown in FIG.

However, in such a folding ruled line, unless the thickness (remaining wall thickness) Q ₁ of the bottom of the groove is considerably reduced with respect to the plate thickness Q of the plastic sheet 1, the bending characteristics cannot be improved. on the other hand, torn from this portion during processing and during bending in the case of providing thin the Zan'nikuAtsu Q ₁ is that there is a problem that occurs. Further, during the processing of the groove, it is necessary to strongly press the ruled line blade against the plastic sheet 1, so that the groove is elongated in the direction of the arrow AB in the figure to generate a strain, and the remaining thickness Q ₁ is made uniform. Depth was difficult. Furthermore, when the ruled line blade is strongly pressed, the plastic molecules gather at the bottom of the groove to increase the density, and the bottom becomes hard, so that there is a disadvantage that it is difficult to bend.

Conventionally, as shown in FIG. 8, a plastic sheet 1 is provided with a groove having a "V" cross section, and a convex portion 101 is formed at the bottom 100 of the groove along the length direction thereof. There are also folding ruled lines.
No. 5 discloses this structure.

However, when the folded crease has such a structure, when the plastic sheet 1 is pressed by the crease blade during the processing of the crease, plastic molecules gather in the shallow convex portion 101 and the molecular density increases. since it becomes hard, inferior properties folded portion of the convex portion 101, correspondingly, the bottom 100 of the groove, unless longer than thinner the thickness (Zan'nikuAtsu) Q _1, obtained soft borders There is no problem.

When the folding ruled line has such a structure, as shown in FIGS. 9A and 9B, the plastic sheet 1 is manufactured and used as a case for storing objects, for example, and is relatively heavy. When an object is placed, the weight of the object may cause a break from the ruled line (the dotted line in FIG. 9A).

Further, in order to form such a structure, when the ruled line blade is pressed to process the ruled line, the entire ruled line blade is inserted deeply into the plastic sheet 1. In the direction (both main surface directions of the ruled line blade), and distortion, warping, waving, etc. occur between the ruled lines, especially when assembling a small transparent case as shown in FIG. 9 (B). However, there is a problem that the corner portion is wavy and the appearance is poor.

Further, in the conventional folding crease structure, warpage occurs when the creases are processed after the plastic sheet 1 is punched out, and the sheet is fed one by one in a sticking process in a subsequent processing step. Therefore, it has been difficult to realize automation for mass production.

The present invention has been proposed in view of such circumstances, and an object of the present invention is to provide a folded creasing-lined plastic sheet having good folding characteristics.

[0011] The present invention also provides a folded crease blade capable of producing a folded creased plastic sheet having good folding characteristics. Further, the present invention provides an automatic cutting machine which does not generate distortion, warping, waving, etc. during processing of the plastic sheet. An object of the present invention is to provide a method for manufacturing a plastic sheet with a folding ruled line, which is easy to realize.

[0012]

SUMMARY OF THE INVENTION According to the present invention, there is provided a plastic sheet provided with a folding ruled line formed by a concave groove, wherein the folded ruled line is formed by a pair of side portions inclined at a predetermined angle and facing each other; Each of the side surfaces has a bottom surface continuous with one end thereof, and each side surface has a plurality of side ribs or a plurality of recesses arranged from one end to the other end continuous with the main surface of the plastic sheet. Protrusions are formed at substantially equal intervals in the longitudinal direction of the side surface portion by one of the grooves.

In the plastic sheet with folded creases of the present invention, the plurality of protrusions formed on each of the side portions have a function of reinforcing the side portions, and when the bottom portion is bent, stress concentrates on the bottom portion. Then, it bends only at the bottom.

Further, in the method for producing a plastic sheet with a folded crease according to the present invention, a flat portion is formed in the blade extending direction, and a pair of inclined surfaces which are continuous with one end of the flat portion and are inclined at a predetermined angle are formed. , On each slope,
From one end side to the other end side that is continuous with the plane portion, using a folded ruled line blade having a cutting edge in which either the concave portion or the protrusion is formed at substantially equal intervals in the longitudinal direction of the inclined surface portion,
The plastic sheet is pressed until the depth of the folding ruled line becomes 0.6 to 0.9 times the sheet thickness.

Further, the present invention relates to a folded ruled line blade provided with a cutting edge forming a bent ruled line recessed in a plastic sheet, wherein the cutting edge has a flat portion formed in a cutting direction and is continuous with the flat portion. In addition, a pair of inclined surface portions inclined at a predetermined angle are formed, and in each inclined surface portion, from one end side to the other end side that is continuous with the flat surface portion, either the concave portion or the protrusion is substantially in the longitudinal direction of the inclined surface portion. They are formed at equal intervals.

In the plastic sheet, the height of the portion formed by the flat portion of the cutting edge becomes constant and the molecular density of the portion becomes constant by the pressing of the folding ruled line blade, so that no distortion occurs. Also, plastic molecules gather and harden at each concave portion of the inclined surface portion or at a concave portion adjacent to the protrusion. Furthermore, since the plastic molecules gather at this part, the force of pulling in the lateral direction is weakened, so when the plastic sheet is thinned by pressing the depth of the folding ruled line to about 0.9 times the sheet thickness Also, no tearing occurs in the portion.

[0017]

Embodiments of the present invention will be described below with reference to the drawings. As shown in FIGS. 1 and 2, a plastic sheet with a folding ruled line to which the present invention is applied is:
A folding ruled line 2 which is a groove recessed in one main surface of the plastic sheet 1 is provided.

The material of the plastic sheet 1 is a single or composite sheet of polyethylene terephthalate, polyvinyl chloride, polypropylene, or the like, and usually has a thickness of about 0.1 mm to 1.0 mm.

As shown in FIG. 1, the folding ruled line 2 includes a bottom portion 3 and a pair of side portions 4 and 5 formed from both ends of the bottom portion 3 to the main surface. A plurality of ribs 6 are formed on each of the side portions 4 and 5.

The bottom surface portion 3 is substantially parallel to the main surface of the plastic sheet 1, and each side surface portion 4 is formed from both ends.
One end of 5 is continuous. The side portions 4 and 5 face each other at substantially the same inclination angle via the bottom portion 3, and one end side thereof is continuous with the main surface of the plastic sheet 1.

A large number of side ribs 6 are formed on each of the side portions 4 and 5 from the side continuous with the bottom portion 3 to the other end side continuous with the main surface of the plastic sheet 1. 6 are uniformly arranged at a predetermined interval (pitch). These side ribs 6 are provided on the side parts 4, 5
The depth (height of the side portions 4, 5) H of the folding ruled line 2 shown in FIG. 2 is made relatively shallow, and the thickness (remaining thickness) Q _{1 of the} bottom portion 3 is thereby reduced. Is about 40% of the thickness of the plastic sheet 1,
Only the bottom part 3 can be easily bent.

Further, as shown in FIG.
The side portions 4 and 5 are arranged at positions where they do not face each other. With such an arrangement, the force applied to the bottom surface portion 3 at the time of bending becomes uniform, and it is difficult for waving or the like to occur. Also, by adopting such an arrangement,
Since the side ribs 6 do not come into contact with each other at the time of bending, it is easy to bend.

With respect to the distance between the lower ends of the side portions 4 and 5, that is, the lower width L ₁ of the folding ruled line 2, which is the width of the bottom portion 3, various trial manufactures and tests were conducted. Good results were obtained when the value was 10% to 40%. In contrast, when the lower width L ₁ to less than 10% value of Q, had broken at this portion during bending. On the other hand, if the value is more than 40%, there arises a problem that bending characteristics are deteriorated such that the line does not become a straight line at the time of bending.

As a result of the test, the upper width L ₂ of the folding ruled line 2 which is the distance between the upper ends of the side portions 4 and 5 is as follows:
The case where the value was 150% to 300% of the sheet thickness Q was good. When the upper width L ₂ 150% value smaller than Q, the side ribs 6 each side portion 4 is bent repeatedly,
Since the fatigue of the folded crease 2 at the time of hitting No. 5 became large, it was easily broken. On the other hand, when the value is larger than 300%, a strong pressing is required at the time of processing the folded ruled line 2, and the width of the ruled line 2 is felt to be quite wide, resulting in poor appearance.

The depth H of the folding ruled line 2 is set to a value of 60% to 90% of the sheet thickness Q, so that the remaining thickness Q _{1 is set.}
(= QH) is preferably set to a value of 40% to 10% of Q. As a result of the test, when the depth H was set to a value smaller than 60% of Q, bending characteristics such as difficulty in bending at the time of bending deteriorated. On the other hand, when H was set to a value larger than 90%, the thickness of the bottom surface portion 3 became too thin, and tearing occurred.

The height D of the protrusion (projection) of the side rib 6
Is preferably 5% to 50% of Q. In the test results, the effect was small when the value was less than 5%, and the characteristics were almost the same as when the side rib 6 was not provided. On the other hand, if the value is more than 50%, the feel of the portion after the ruled line portion is bent becomes poor.

In order to manufacture the folded creasing ruled plastic sheet of the present invention, as shown in FIG. 3, it has a flat portion 11 in the blade extending direction and is continuous with the flat portion 11 and is inclined at a predetermined angle. The plastic sheet 1 is formed by using a folded ruled line blade 10 having a pair of inclined surface portions 12 and 13, and having a cutting edge in which concave grooves 14 are arranged at substantially equal intervals from the flat surface portion 11 on each inclined surface portion 12 and 13. Is pressed until the depth H of the folding ruled line 2 becomes 0.6 to 0.9 times the sheet thickness Q.

More specifically, as shown in FIG. 4, the plastic sheet 1 is placed on a pedestal 15 made of an iron plate or the like.
By pressing the folding ruled blade 10 substantially perpendicularly to the main surface of the plastic sheet 1, the folding ruled line 2 is pressed.
Is formed.

At this time, since the height Q ₁ of the bottom portion 3 of the plastic sheet 1 becomes constant by the pressing of the folding ruled blade 10, the molecular density of the bottom portion 3 becomes constant and no distortion occurs. In addition, plastic molecules gather at the location of the side ribs 6 and become hardened, and the above-described side portions 4 and 5 are reinforced to have a positive effect. In addition, since the plastic molecules gather in this portion, the force applied in the horizontal direction (the left and right direction in FIGS. 2 and 6) is reduced, and the pulling force in this direction is weak. the thickness) torn even when the thickness of the Q ₁ to about 10% of the sheet thickness Q does not occur.

The plastic sheet with the folding ruled line manufactured by the above-described method has good folding characteristics at the folding ruled line, and is unlikely to cause warping, waving, and springback even after bending. Therefore, according to the method for producing a folded crease-lined plastic sheet of the present invention, since warpage hardly occurs after bending, it becomes possible to easily feed one sheet at a time in a pasting step as a subsequent processing step. As a result, mass production by automation becomes possible.

According to the plastic sheet with folded creases of the present invention, the plurality of side ribs 6 formed on the side portions 4, 5 have a function of reinforcing the side portions 4, 5.
When the bottom portion 3 is bent, stress concentrates on the bottom portion 3 to bend only at the bottom portion 3, so that the bending characteristics are good, and the height (thickness) of the bottom portion 3 depends on the use of the plastic sheet 1. is) setting range for Q ₁ becomes possible wider. That is, for example, when the case shown in FIGS. 9A and 9B is manufactured and used to put a relatively heavy object, the thickness Q ₁ of the bottom surface portion 3 is made thicker so that It is possible to prevent tearing, and even in this case, there is no problem in appearance such as a wavy corner.

In the above-described embodiment, the cross-sectional shape of the side rib 6 of the folding ruled line 2 is an arc. However, the present invention is not limited to this. A rectangular shape, a trapezoidal shape, a triangular shape, and various other shapes are possible. When the cross-sectional shape of the side rib 6 is set to these shapes, the folding ruled blade 10
May be changed to a shape corresponding to the side rib 6.

In the above-described embodiment, the folded ruled line 2 has a so-called mountain structure in which a plurality of side ribs 6 projecting from the side portions 4 and 5 are formed. However, the present invention is not limited to this. Instead, as shown in FIG. 5, a so-called valley structure in which a plurality of recessed grooves 7 recessed with respect to the side surfaces 4 and 5 may be formed. In this case, the main surfaces of the side portions 4 and 5 become projections. In this case, as shown in FIG. 6, the folded ruled line blades are formed such that a large number of projections 16 projecting from the flat surface 11 on the inclined surfaces 12 and 13 are arranged at substantially equal intervals. As a result, the inclined surface 1 adjacent to the projection 16
The main surfaces 2 and 13 have a function similar to that of the concave groove 14 in FIG. 3, that is, a region where plastic molecules gather when the plastic sheet 1 is pressed.

[0034]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of a plastic sheet with a folding ruled line will be described below. In this example, a sheet of amorphous polyethylene terephthalate (A. PET) having a thickness of 0.3 mm was used as a material of the plastic sheet 1. And about the side rib 6 of the bending ruled line 2,
The sectional shape as shown in FIG. 1 was an arc shape.

In this embodiment, the value of the lower width L ₁ of the folding ruled line 2 is set to 0.1 mm (about 3 times the value of the sheet thickness Q).
3%), about 16 the value of the upper width L ₂ 0.5 mm (the value of Q
6%) and the value of the depth H is 0.22 mm (about 73% of the value of Q).
%), The value of the height D of the swelling of the side rib 6 is 0.05
mm (about 16% of the value of Q), 0.08 and values of Zan'nikuAtsu Q ₁
mm (approximately 26% of the value of Q). Further, the value of the pitch P of each side rib 6 shown in FIG.
m, and the value of the width S of each side rib 6 was set to 0.1 mm. Then, the concave groove 14 was formed on the edge of the folding ruled line blade 10 so as to conform to the set value. The angle of the cutting edge of the bent border blade 10 at this time (the angle shown in FIG. 3 theta) was set to 80 ° approximately, the thickness L ₃ of the base end side of the blade was set to 1.0 mm.

Then, as described with reference to FIG. 4, the plastic sheet 1 is placed on the pedestal 15 made of an iron plate.
0 was pressed, and the cutting edge was cut into the plastic sheet 1.

The plastic sheet 1 with the ruled line thus formed has good folding characteristics. Specifically, when the plastic sheet 1 is bent at the folded ruled line 2, it is bent only at the bottom portion 3 and is thin. A sharp bent portion was obtained, and the springback after bending was small. Further, the durability of the folded ruled line 2 was also excellent. As a result of a bending test in which the bent ruled line 2 was repeatedly bent at an angle of 360 °, no damage was caused even when the bent line was repeatedly bent 30 times.

[0038]

As described in detail above, according to the plastic sheet with folded creases of the present invention, the plurality of projections formed on each of the side portions have the function of reinforcing the side portions and the bottom portion. When the is bent, stress concentrates on the bottom part and bends only at the bottom part, so the bending characteristics are good and the setting range of the thickness of the bottom part can be widened according to the application of the plastic sheet etc. Becomes

Further, according to the folding ruled blade and the method of manufacturing a plastic sheet with a folded ruled line of the present invention, the height of the portion formed by the flat portion of the cutting edge becomes constant by pressing the folding ruled line blade, and Since the molecular density is constant, no plastic strain is generated, and plastic molecules gather and harden at each concave portion of the inclined surface portion or at a concave portion adjacent to the protrusion. Moreover,
Since the plastic molecules gather in this part, the force to be pulled in the lateral direction is weakened, so even if the plastic sheet is thinned by pressing the depth of the folding ruled line to about 0.9 times the sheet thickness, No tearing occurs in the part. Therefore, distortion, warpage, waving, and the like do not occur during processing of the plastic sheet, and automation can be easily realized.

[Brief description of the drawings]

FIG. 1 is a perspective view of a main part showing a configuration of a plastic sheet with a folded crease according to the present invention.

FIG. 2 is a main part side view showing a configuration of the plastic sheet containing the folding ruled lines.

FIG. 3 is a perspective view of a main part showing a configuration of a folding ruled line blade of the present invention.

FIG. 4 is a cross-sectional view for explaining a method for producing the above-mentioned plastic sheet with folded creases.

FIG. 5 is a perspective view of a main part showing another embodiment of the plastic sheet containing the folding ruled lines.

FIG. 6 is a main part perspective view showing another embodiment of the folding ruled line blade.

FIGS. 7A and 7B are cross-sectional views illustrating the structure of a conventional folding ruled line provided on a plastic sheet, where FIG. 7A is a substantially U-shaped cross-section and FIG. 7B is a substantially W-shaped cross-section; Are shown below.

FIG. 8 is a perspective view showing the structure of a conventional folding ruled line.

9A and 9B are diagrams illustrating a case in which a plastic sheet with a folding ruled line is used as a case for placing an object, wherein FIG. 9A is a development view, and FIG. It is.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Plastic sheet 2 Folded ruled line 3 Bottom part 4,5 Side part 6 Side rib 7 Depressed groove 10 Folded ruled line blade 11 Flat part 12,13 Inclined surface part 14 Depressed groove 15 Cradle 16 Projection part

Claims (5)

[Claims] 1. A plastic sheet provided with a folding ruled line formed by a concave groove, wherein the folded ruled line includes a pair of side portions inclined at a predetermined angle and facing each other, and a bottom portion connected to one end of each side portion. Having a plurality of side ribs or a plurality of recessed grooves arranged from the one end to the other end continuous with the main surface of the plastic sheet. A plastic sheet with a folding ruled line, wherein projections are formed at substantially equal intervals in a longitudinal direction. 2. The plastic sheet according to claim 1, wherein the projections are formed at positions where the side portions do not face each other. 3. The height of each of the side portions is equal to 0.
6 to 0.9 times, the width of the bottom surface is 0.1 to 0.4 times the sheet thickness, and the distance between the other ends of the side surfaces is 1. 5 to 3.0 times, and the height of the protrusion of the protrusion is 0.05 to 0.5 times the sheet thickness.
2. The plastic sheet according to claim 1, wherein the plastic sheet is doubled. 4. A flat portion is formed in the blade extending direction, and a pair of inclined surfaces which are continuous with the flat portion and are inclined at a predetermined angle are formed, and each of the inclined surfaces is continuous with the flat portion. From the one end side to the other end side, using a folding ruled line blade having a cutting edge in which either the recessed portion or the projecting portion is formed at substantially equal intervals in the longitudinal direction of the inclined surface portion, the plastic sheet is bent at the depth of the folded ruled line. Is pressed until the sheet thickness becomes 0.6 to 0.9 times the sheet thickness. 5. A folding ruled line blade provided with a cutting edge for forming a folding ruled line depressed in a plastic sheet, wherein the cutting edge has a flat portion formed in a cutting direction and is continuous with the flat portion at a predetermined angle. A pair of inclined surfaces are formed, and each of the inclined surfaces has a recess or a protrusion extending from one end side to the other end that is continuous with the flat surface portion at substantially equal intervals in the longitudinal direction of the inclined surface portion. A folded ruled line blade characterized by being formed by: