JP4243881B2 - Folded ruled plastic sheet, method for producing the same and bent ruled blade - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a plastic sheet with a folded ruled line, a method for producing the same, and a folded ruled line blade.
[0002]
[Prior art]
Conventionally, when a plastic sheet is bent to assemble a packaging container or a case of an article, a groove-like ruled line (hereinafter referred to as a crease) that has been recessed in advance in a bent portion of the plastic sheet in order to perform accurate folding. It was formed by pressing the ruled line blade and was bent along the bent ruled line.
[0003]
[Problems to be solved by the invention]
Conventionally, the bent ruled lines provided on the plastic sheet have various shapes and structures. As a conventional folding ruled line structure, for example, as shown in FIG. 7 (A), a groove having a substantially “U” -shaped cross section is provided from the main surface of the plastic sheet 1, or a cross section as shown in FIG. A "W" type groove is known.
[0004]
However, in such a folding ruled line, the bending characteristic cannot be improved unless the thickness (remaining thickness) Q ₁ of the bottom of the groove is considerably reduced with respect to the plate thickness Q of the plastic sheet 1. When the remaining thickness Q ₁ is thin, there is a problem that tearing occurs from this portion during processing or bending. Further, when the groove is processed, it is necessary to strongly press the ruled line blade against the plastic sheet 1, and for this reason, the groove is extended in the direction of the arrow AB in the figure, and the remaining thickness Q ₁ is made uniform. Depth was difficult. Furthermore, by strongly pressing the ruled line blade, the plastic molecules gather at the bottom of the groove and the density thereof becomes high, and the bottom becomes hard, which makes it difficult to bend.
[0005]
Conventionally, as shown in FIG. 8, the plastic sheet 1 is provided with a groove having a "V" cross section, and a bent ruled line having a structure in which a convex portion 101 is formed along the length direction at the bottom 100 of the groove. In detail, the structure is described in Japanese Utility Model Publication No. 4-9345.
[0006]
However, when the folded ruled line has such a structure, when the plastic sheet 1 is pressed with the ruled line blade during the ruled line processing, the plastic molecules gather on the shallow convex portions 101, and the molecular density increases and becomes hard. put away because, 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, is not obtained soft borders, that There's a problem.
[0007]
Further, 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 putting an object, for example, and a relatively heavy object is put therein. In such a case, the tear may occur from the ruled line (dotted line in FIG. 9A) due to the weight of the object.
[0008]
Furthermore, in order to obtain such a structure, when the ruled line blade is pressed to process the ruled line, the entire ruled line blade is deeply inserted into the plastic sheet 1 so that the plastic sheet 1 is laterally (ruled line). In the case of assembling a small transparent case as shown in FIG. 9B, in particular, distortion, warpage, undulation, etc. occur between the ruled lines. There was a problem that the appearance of the appearance deteriorated due to undulations at the corners.
[0009]
Furthermore, in the conventional folding ruled line structure, warping occurs when the ruled line is punched after the plastic sheet 1 is punched, and it becomes impossible to feed one sheet at a time in the pasting process of the subsequent process. Therefore, it has been difficult to realize automation for mass production.
[0010]
The present invention has been proposed in view of such circumstances, and an object of the present invention is to provide a folded ruled plastic sheet having good folding characteristics.
[0011]
In addition, the present invention provides a folding ruled line blade capable of producing a plastic sheet with a folded ruled line having good folding characteristics, and does not cause distortion, warpage, undulation, etc. during the processing of the plastic sheet, and can easily realize automation. An object of the present invention is to provide a method for producing a plastic sheet with a simple bent ruled line.
[0012]
[Means for Solving the Problems]
The present invention that has solved the above problems is a plastic sheet provided with a folding ruled line by a concave groove, wherein the folding ruled line is continuous with a pair of side surfaces inclined at a predetermined angle and facing each other, and one end side of each side surface part. Each side surface portion is provided with either a plurality of side ribs or a plurality of recessed grooves arranged from one end side to the other end side continuous with the main surface of the plastic sheet. Projections are formed at substantially equal intervals in the longitudinal direction.
[0013]
In the folded ruled plastic sheet of the present invention, the plurality of protrusions formed on each of the side surfaces have a function of reinforcing the side surface, and when the bottom surface is bent, stress concentrates on the bottom surface, and the bottom surface It bends only at the part.
[0014]
Further, in the method for producing a folded ruled plastic sheet according to the present invention, a flat portion is formed in the blade span direction, and a pair of inclined surface portions that are continuous with one end side of the flat portion and are inclined at a predetermined angle are formed. For the surface portion, from one end side continuous to the flat surface portion to the other end side, using a folded ruled line blade having a cutting edge in which either the recessed portion or the protruding portion is formed at substantially equal intervals in the longitudinal direction of the inclined surface portion, The plastic sheet is pressed until the folding ruled line has a depth of 0.6 to 0.9 times the sheet thickness.
[0015]
Furthermore, the present invention provides a folded ruled line blade having a cutting edge that forms a bent ruled line that is recessed in a plastic sheet. The cutting edge is formed with a flat part in the spanning direction, and is continuous with a predetermined angle with respect to the flat part. A pair of inclined surface portions that are inclined with respect to each other are formed, and each of the inclined surface portions has either a recessed portion or a protruding portion at substantially equal intervals in the longitudinal direction of the inclined surface portion from one end side to the other end side continuous with the flat surface portion. It is formed.
[0016]
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 due to the pressing of the folding ruled line blade, so that no distortion occurs. In addition, plastic molecules gather at the positions of the recessed portions of the inclined surface portion or the recessed portions adjacent to the protrusions and become hard. In addition, since the plastic molecules gather in this area, the pulling force in the lateral direction is weakened, so when the plastic sheet is thinned by pressing the folding ruled line depth to about 0.9 times the sheet thickness In addition, no tearing occurs in this part.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. As shown in FIGS. 1 and 2, the plastic sheet with a folded ruled line to which the present invention is applied is provided with a folded ruled line 2 that is a groove recessed in one main surface of the plastic sheet 1.
[0018]
The material of the plastic sheet 1 is a single or composite sheet such as polyethylene terephthalate, polyvinyl chloride, or polypropylene, and usually has a thickness of about 0.1 mm to 1.0 mm.
[0019]
As shown in FIG. 1, the bent ruled line 2 includes a bottom surface portion 3 and a pair of side surface portions 4 and 5 formed from both ends of the bottom surface portion 3 to the main surface. A plurality of side surfaces 4 and 5 are formed.
[0020]
The bottom surface portion 3 is substantially parallel to the main surface of the plastic sheet 1, and one end side of each of the side surface portions 4 and 5 is continuous from both end portions. The side surface parts 4 and 5 face each other at substantially the same inclination angle via the bottom surface part 3, and one end side thereof is continuous with the main surface of the plastic sheet 1.
[0021]
Each of the side surface portions 4 and 5 is formed with a large number of side surface ribs 6 from the side continuous with the bottom surface portion 3 to the other end side continuous with the main surface of the plastic sheet 1. Are evenly arranged at a predetermined interval (pitch). These side ribs 6 have a function of reinforcing the side surface portions 4 and 5, thereby making the depth (the height of the side surface portions 4 and 5) H of the bent ruled line 2 shown in FIG. Even when the thickness (remaining thickness) Q ₁ of the portion 3 is about 40% of the plate thickness of the plastic sheet 1, only the bottom surface portion 3 can be easily bent.
[0022]
Further, as shown in FIG. 1, the side ribs 6 are arranged at positions where the side surface portion 4 and the side surface portion 5 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 undulation or the like hardly occurs. Moreover, since it becomes such arrangement | positioning, since the side surface ribs 6 do not touch at the time of bending, it becomes easy to bend.
[0023]
As for the distance between the lower ends of the side surface parts 4 and 5, that is, the lower width L ₁ of the folding ruled line 2 that is the width of the bottom surface part 3, as a result of various trial manufactures and tests, 10% of the sheet thickness Q Good results were obtained with values of ˜40%. On the other hand, when the lower width L ₁ was set to a value smaller than 10% of Q, the portion was cut at this portion during bending. On the other hand, when the value is larger than 40%, there arises a problem that the bending characteristic is deteriorated, for example, the line does not become a straight line during bending.
[0024]
As a result of the test, the upper width L ₂ of the folding ruled line 2 that is the distance between the upper end sides of the side surface parts 4 and 5 was good when it was set to a value of 150% to 300% of the sheet plate thickness Q. When the upper width L ₂ is set to a value smaller than 150% of Q, the bending ruled line 2 becomes more fatigued when it is repeatedly bent and the side ribs 6 come into contact with the side surfaces 4 and 5, so that it easily breaks. On the other hand, if the value is larger than 300%, strong pressing is required when processing the folded ruled line 2, and the width of the ruled line 2 is felt to be quite wide, resulting in poor appearance.
[0025]
The depth H of the folding ruled line 2 is set to a value of 60% to 90% of the sheet thickness Q, and therefore the remaining thickness Q ₁ (= Q−H) is set to a value of 40% to 10% of Q. preferable. As a result of the test, when the depth H was set to a value smaller than 60% of Q, the bending characteristics such as difficulty in bending were 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.
[0026]
The height D of the bulge (protrusion) of the side rib 6 is preferably set to a value of 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 ribs 6 were not provided. On the other hand, when the value is larger than 50%, the feel of the part after the ruled line part is bent is deteriorated.
[0027]
In order to manufacture the plastic sheet with a bent ruled line of the present invention, as shown in FIG. 3, a pair of slopes having a flat surface portion 11 in the blade spanning direction and continuous with the flat surface portion 11 at a predetermined angle. The plastic sheet 1 is bent using the folding ruled line blade 10 having the surface portions 12 and 13, and the inclined surface portions 12 and 13 having the cutting edges in which the recessed grooves 14 are arranged at substantially equal intervals from the flat surface portion 11 side. A method of pressing until the depth H of the ruled line 2 becomes 0.6 to 0.9 times the sheet thickness Q is used.
[0028]
Specifically, as shown in FIG. 4, the plastic sheet 1 is placed on a cradle 15 made of an iron plate or the like, and the folding ruled line blade 10 is pressed substantially perpendicularly to the main surface of the plastic sheet 1. As a result, the folded ruled line 2 is formed.
[0029]
At this time, since the height Q ₁ of the bottom surface portion 3 becomes constant due to the pressing of the folding ruled line blade 10 in the plastic sheet 1, the molecular density of the bottom surface portion 3 becomes constant and no distortion occurs. In addition, plastic molecules gather at the side ribs 6 and become hard, which acts positively by reinforcing the side portions 4 and 5 described above. Further, since plastic molecules gather in this portion, the force applied in the lateral direction (left and right directions in FIGS. 2 and 6) is reduced, and the force pulled in this direction is weak. Thickness) No tearing occurred when Q ₁ was reduced to about 10% of the sheet thickness Q.
[0030]
The plastic sheet with a folded ruled line produced by the above-described method has good folding characteristics at the folded ruled line, and is less likely to be warped, wavy, or springback after being folded. Therefore, according to the method for producing a folded ruled plastic sheet of the present invention, warping is less likely to occur after the bending process, so that it is possible to easily feed one sheet at a time in the pasting process as a subsequent processing step. As a result, mass production by automation becomes possible.
[0031]
Further, according to the plastic sheet with a folded ruled line of the present invention, the plurality of side surface ribs 6 formed on the side surface portions 4 and 5 have a function of reinforcing the side surface portions 4 and 5 and the bottom surface portion 3 is bent. Since the stress concentrates on the bottom surface portion 3 and bends only at the bottom surface portion 3, the bending characteristic is good, and the setting range of the height (thickness) Q ₁ of the bottom surface portion 3 according to the use of the plastic sheet 1 or the like. Can be taken widely. That is, for example, in the case of manufacturing and using the case of FIGS. 9A and 9B and putting a relatively heavy object, the thickness from the ruled line portion can be increased by increasing the thickness Q ₁ of the bottom surface portion 3. It is possible to prevent tearing, and even in this case, there is no problem in appearance such as undulation of the corner portion.
[0032]
In the embodiment described above, the cross-sectional shape of the side rib 6 is an arc shape with respect to the bent ruled line 2, but the present invention is not limited to this, and the cross-sectional shape of the side rib 6 is rectangular. A trapezoidal shape, a triangular shape, and other various shapes can be used. When the cross-sectional shape of the side rib 6 is set to these shapes, the recessed groove 14 of the bent ruled line blade 10 may be changed to a shape corresponding to the side rib 6.
[0033]
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 surfaces 4 and 5 are formed. However, the present invention is not limited to this. As shown in FIG. 5, a so-called valley structure in which a plurality of recessed grooves 7 that are recessed with respect to the side surface portions 4 and 5 are formed may be employed. In this case, the main surface itself of the side surface parts 4 and 5 becomes a projection part. In this case, as shown in FIG. 6, the bent ruled line blades are formed so that a large number of protruding portions 16 protruding from the flat surface portion 11 side are arranged on the inclined surface portions 12 and 13 at substantially equal intervals. As a result, the main surfaces of the inclined surface portions 12 and 13 adjacent to the projection portion 16 have the same function as the recessed groove 14 in FIG. 3, that is, plastic molecules gather when the plastic sheet 1 is pressed. It will be the place to come.
[0034]
【Example】
Hereinafter, an embodiment of a plastic sheet with bent ruled lines will be described. In this example, a sheet of amorphous polyethylene terephthalate (A.PET) having a thickness of 0.3 mm was used as the material for the plastic sheet 1. And about the side surface rib 6 of the bending ruled line 2, the cross-sectional shape as shown in FIG.
[0035]
In this embodiment, the value of the lower width L ₁ of the folded ruled line 2 is 0.1 mm (about 33% of the sheet thickness Q value), and the value of the upper width L ₂ is 0.5 mm (about Q value). 166%), the depth H value is 0.22 mm (about 73% of the Q value), the height D of the side rib 6 is 0.05 mm (about 16% of the Q value), and the remaining meat The value of the thickness Q ₁ was set to 0.08 mm (about 26% of the Q value). Furthermore, the value of the pitch P of each side rib 6 shown in FIG. 1 was set to 0.5 mm, and the value of the width S of each side rib 6 was set to 0.1 mm. And the recessed groove 14 was formed so that it might adapt to this setting value about the blade edge | tip of the bending ruled line blade 10. FIG. At this time, the angle of the cutting edge of the folded ruled line blade 10 (angle θ shown in FIG. 3) was about 80 degrees, and the thickness L ₃ on the base end side of the blade was 1.0 mm.
[0036]
Then, as described with reference to FIG. 4, the plastic sheet 1 is placed on the cradle 15 made of an iron plate, the bent ruled line blade 10 is pressed from above the plastic sheet 1, and the cutting edge is bitten into the plastic sheet 1. Let
[0037]
The plastic sheet 1 with ruled lines thus formed has good folding characteristics. Specifically, when the plastic sheet 1 is folded at the folded ruled line 2 part, the plastic sheet 1 is folded only at the bottom surface part 3 and is thin and sharp. Part was obtained, and there was little spring back after bending. Further, the folding ruled line 2 was excellent in durability. As a result of a bending test in which bending was repeated at an angle of 360 degrees, the folding ruled line 2 was not damaged even after repeated folding 30 times.
[0038]
【The invention's effect】
As described above in detail, according to the plastic sheet with a folded ruled line of the present invention, when a plurality of protrusions formed on each of the side surface portions have a function of reinforcing the side surface portion and the bottom surface portion is bent. Since stress concentrates on the bottom surface portion and it bends only at the bottom surface portion, the bending characteristics are good, and it becomes possible to take a wide setting range of the thickness of the bottom surface portion according to the use of the plastic sheet.
[0039]
In addition, according to the method of manufacturing the folded ruled line blade and the folded ruled line plastic sheet of the present invention, the height of the portion formed by the flat portion of the blade edge becomes constant by pressing the folded ruled line blade, and the molecular density of the portion Therefore, distortion does not occur, and plastic molecules gather and harden at the recessed portions adjacent to the protrusions or at the recessed portions adjacent to the protrusions. In addition, since the plastic molecules gather in this area, the pulling force in the lateral direction is weakened, so when the plastic sheet is thinned by pressing the folding ruled line depth to about 0.9 times the sheet thickness In addition, no tearing occurs in this part. Accordingly, no distortion, warpage, undulation or the like occurs 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 bent ruled lines according to the present invention.
FIG. 2 is a side view of the main part showing the configuration of the bent ruled plastic sheet.
FIG. 3 is a perspective view of a main part showing a configuration of a folded ruled line blade of the present invention.
FIG. 4 is a cross-sectional view for explaining a method for producing the bent ruled plastic sheet.
FIG. 5 is a perspective view of a principal part showing another embodiment of the plastic sheet with bent ruled lines.
FIG. 6 is a main part perspective view showing another embodiment of the bent ruled line blade.
FIG. 7 is a cross-sectional view illustrating the structure of a conventional folding ruled line provided on a plastic sheet, where (A) is a substantially “U” -shaped structure, and (B) is a substantially “W” -shaped structure; Each case is shown.
FIG. 8 is a perspective view showing a structure of a conventional folding ruled line.
FIGS. 9A and 9B are diagrams illustrating a case where a plastic sheet with a folded ruled line is used as a case for putting an object, FIG. 9A is a development view, and FIG. 9B is a perspective view when the folded ruled line is folded to form the case. It is.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Plastic sheet 2 Bending ruled line 3 Bottom face part 4, 5 Side face part 6 Side rib 7 Recessed groove 10 Bending ruled line blade 11 Plane part 12, 13 Inclined surface part 14 Recessed groove 15 Base 16 Protrusion part

Claims (5)

In the plastic sheet provided with the folding ruled line by the groove,
The bent ruled line has a pair of side surfaces that are inclined at a predetermined angle and face each other, and a bottom surface that is continuous with one end side of each side surface portion. Protrusions are formed at substantially equal intervals in the longitudinal direction of the side surface portion by any of a plurality of side surface ribs or a plurality of recessed grooves arranged over the other end side continuous with the main surface. Bending ruled plastic sheet. 2. The plastic sheet with bent ruled lines according to claim 1, wherein the protrusions are formed at positions where the side portions do not face each other. The height of each side part is 0.6 to 0.9 times the sheet thickness, and the width of the bottom part is 0.1 to 0.4 times the sheet thickness, The distance between the other ends of the sheet is 1.5 to 3.0 times the sheet thickness, and the protrusion height of the protrusion is 0.05 to 0.5 times the sheet thickness. The plastic sheet with folded ruled lines according to claim 1, wherein the plastic sheet is bent. A flat portion is formed in the blade spanning direction, and a pair of inclined surface portions that are continuous with respect to the flat portion and inclined at a predetermined angle are formed, and each inclined surface portion has the other end from one end side continuous with the flat portion. Using a folded ruled line blade having a cutting edge in which either the recessed part or the protruding part is formed at substantially equal intervals in the longitudinal direction of the inclined surface part, the plastic sheet is formed with a depth of the folded ruled line having a sheet thickness. A method for producing a plastic sheet with a bent ruled line, wherein the sheet is pressed until 0.6 to 0.9 times. In the folding ruled line blade with a cutting edge that forms a folded ruled line recessed in the plastic sheet,
The blade edge is formed with a flat surface portion in the blade crossing direction, and a pair of inclined surface portions that are continuous with respect to the flat surface portion and are inclined at a predetermined angle,
Each of the inclined surface portions is formed with a crease ruled line in which either a recessed portion or a protruding portion is formed at substantially equal intervals in the longitudinal direction of the inclined surface portion from one end side to the other end side continuous with the flat surface portion. blade.

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