JPH02162015A - Plastic sheet with ruled line and method for drawing ruled line - Google Patents

Abstract

PURPOSE:To realize a ruled line easily along which breakage is hard to develop, by a method wherein the bottom wall of the ruled line projects to one surface side of a plastic sheet and the cross-sectional shape of the ruled line is made to be thick at its central part and thinner and its both sides than at its central part. CONSTITUTION:The bottom wall of a ruled line projects to one surface side of a plastic sheet 2. The cross-sectional shape of the ruled line 1 is made to be thick at its central part 11 and thinner at its both sides 12 than at its central part. When the ruled line 1 is drawn by pinchingly pressing the plastic sheet 2 with a male mold 3 and a female mold 4, the width W of the female mold is set to be 2 - 4 times the thickness T of the plastic sheet and the clearance A between the female mold and the male mold is set to be 0.2 - 0.7 times the thickness T of the plastic sheet. Further, the male mold 3 is fitted into the female mold 4 to the depth B, which is 0.5 - 3 times the thickness of the plastic sheet. As the plastic sheet 2, rigid sheet or semirigid sheet, which is made of polyvinyl chloride, polypropylene or the like and the thickness of which is about 0.1 - 1.0mm, is employed. Thus, a plastic sheet having a ruled line 1, is obtained easily and breakage is hard to develop, is realized.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to a plastic sheet provided with a crease for folding, and especially a crease for attaching creases to a hard plastic sheet having a thickness of 0.1 to 1 mm. Regarding the attachment method.

(Prior Art and Problems to be Solved by the Invention) Conventionally, there is a method described in Japanese Patent Publication No. 31036/1983 as a method for attaching folding lines to a plastic sheet. As shown in the cross-sectional view of FIG. 3, this is attached by pressing the plastic sheet 2 between the male die 3 and the female die 4, but the bottom wall of the resulting ruled line 1 is
Although it protrudes from one side of the plastic sheet and is thinner overall, making it easier to bend, there is a risk of damage due to external force due to the thinness. Further, in this method, as shown in FIG. 3, it is necessary to press the plastic sheet 2 with an elastic material 5 to prevent it from being drawn into the female mold 4, which requires strong pressure and is complicated.

(Means for Solving the Problems) The present invention has been made to solve the above problems, and will be described below based on the drawings.

FIG. 1 is a perspective view showing an example of a plastic sheet provided with ruled lines according to the present invention, FIG. 2 is a cross-sectional view illustrating a state in which ruled lines are attached to a plastic sheet using the ruled line attaching method of the present invention, and FIG. 3 FIG. 2 is a cross-sectional view showing an example of a state in which ruled lines are attached to a plastic sheet using a conventional ruled line attaching method.

As shown in FIG. 1.2, the present invention provides: 1) a plastic sheet 2 provided with ruled lines 1, in which the bottom wall of the ruled lines protrudes toward one side of the plastic sheet 2, and the cross-sectional shape of the ruled lines is formed in the central portion; A plastic sheet provided with ruled lines, which is thick at 11 and thinner at both sides 12 than at the center.

2) A method of attaching ruled lines 1 by pressing the plastic sheet 2 between a male mold 3 and a female mold 4, in which the width W of the female mold is 2 to 4 times the thickness T of the plastic sheet, and the female mold and the male mold are The gap A with the mold is the thickness T of the plastic sheet Q, 2 to 0.
7 times, and the male mold 3 is 0.5 times the thickness of the plastic sheet.
A ruled line attaching method characterized by fitting into a female mold 4 up to a depth B of ~3 times.

It is related to.

The plastic sheet 2 of the present invention may be made of polyvinyl chloride, polypropylene, etc. f51! A rigid sheet or a semi-rigid sheet can be used. Its thickness is usually 0,
1 to about 1.01 can be used.

As shown in FIG. 1, the bottom wall of the ruled line 1 protrudes from one side of the plastic sheet, providing a margin for bending, and combined with the fact that both sides are thinner, the plastic sheet is extremely easy to bend. Furthermore, since the central portion is thick, even if an external force is applied to the bent corners, it will have a reinforcing effect and will not be easily damaged.

As a method for attaching such ruled lines 1, as shown in Fig. 2, tAW of the female mold 4 is the thickness T of the plastic sheet.
It is necessary to make it 2 to 4 times the amount. If it is smaller than twice, the width of the ruled line obtained will be small, and it will be difficult to bend it. On the other hand, if it is larger than 4 times, the width of the resulting ruled line will be large and unsightly.

The male mold 3 needs to be set according to the female mold 4, but it is preferable that the gap A when fitted to the female mold 4 is 0.2 to 0.7 times the thickness T of the plastic sheet. . Both sides 12 of the ruled line 1 are stretched thinly between the gaps.

As shown in FIG. 2, when the plastic sheet 2 is placed on the male mold 4 and the male mold 3 is pressed from the opposite side to fit with the female mold, the depth B is the thickness T of the plastic sheet 2. 0.
5 to 3 times is appropriate. If it is smaller than 0.5 times, the resulting thin portions on both sides 12 of the ruled line will become thin, and the effect of softening the ruled line will be small. On the other hand, if it is larger than 3 times, the degree of protrusion of the obtained ruled line 1 will be too severe, and the protruding shape of the ruled line will remain even when folded, which is uncomfortable, and both sides 12 will be stretched thin and weak.

The shape of the tip of the male mold 3 can be rounded and rounded as shown in FIG. 2 to prevent scratches on the plastic sheet. However, if this R is too large, there is a risk that the plastic sheet may be partially dragged in when fitting into the female mold, causing undulations around the ruled lines.
This R is preferably approximately the thickness T of the plastic sheet.

The cross-sectional shape of the bottom of the female mold 4 may be a boat bottom shape or a U-shape as shown in Figure 2, or it may be made deeper to prevent the Plus Deck sheet from being pinched when the male mold 3 is fitted. By sandwiching it between the male mold 3, the bottom of the ruled line of the plastic sheet can be shaped into a certain shape, embossed,
The depth may be set so that lines or the like can be formed.

By heating the male die 3, the female die 4, or the plastic sheet, the ruled line processing portion may be softened to prevent whitening due to processing stress, and the pressure necessary for processing may be reduced.

In addition, by applying ultrasonic vibration to the male die 3 or the female die 4, the plastic sheet 2 sandwiched between the two dies is heated and softened by frictional heat, reducing the clamping force necessary for attaching ruled lines and reducing stress. This can prevent whitening and damage caused by. In this case, the amplitude of the ultrasonic vibration is preferably 5 to 40 microns, and the vibration time is preferably about 0.05 to 1.0 seconds. and,
As shown in Figure 2, the ultrasonic vibrations can be applied continuously until the male mold is mated to the female mold, or the ultrasonic vibrations can be stopped once the plastic sheet is heated, and then the mating is complete. You may also do so.

The male mold 3 and the male mold 4 may be attached to a flat white plate, or may be formed into a disk shape to enable continuous processing.

(Example) A hard polyvinyl chloride sheet with a thickness of 0.2 mm was used as the plastic sheet 2, and in FIG. 2, the width W of the female mold 4 was 0.8 mm, and the width W of the male mold was 0.6 mm1. Therefore, the plastic sheet was placed between the male molds with a gap A of 0.1 mm, and the male mold 3 was fitted into the female mold 4 to a depth of 0°3 nm. As a result,
A plastic sheet having the shape shown in FIG. 1 and having ruled lines 1 that was easy to fold and hard to break was obtained.

However, if the temperature of the male die 3 was heated to about 70°C at this time, stable processing was possible without any whitening occurring in the ruled line area.

(Effects of the Invention) The present invention provides a plastic sheet provided with ruled lines, in which the bottom wall of the ruled line protrudes to one side of the plastic sheet, and the cross-sectional shape of the ruled line is thicker at the center and thinner at both sides than at the center. Since it is a plastic sheet with ruled lines, it is extremely easy to bend and is not easily damaged.

Furthermore, it is a method of attaching ruled lines by squeezing a plastic sheet with a male die and a female die, and the width of the female die is 2 to 4 times the thickness of the plastic sheet, and the gap between the female die and the male die is the width of the plastic sheet. The thickness of the plastic sheet is 0.2 to 0.7 times the thickness of the plastic sheet, and the male mold is fitted to the female mold to a depth of 0.5 to 3 times the thickness of the plastic sheet. Special ruled lines can be easily added to a plastic sheet simply by adjusting the shapes of the mold and female mold.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing an example of a plastic sheet provided with ruled lines according to the present invention, FIG. 2 is a cross-sectional view illustrating a state in which ruled lines are attached to a plastic sheet using the ruled line attaching method of the present invention, and FIG. 3 FIG. 2 is a cross-sectional view showing an example of a state in which ruled lines are attached to a plastic sheet using a conventional ruled line attaching method. 1... Ruled line 11... Center part 12... Both sides 2... Plastic sheet 3... Male mold 4...
・Female mold W... Width of female mold T... Thickness of plastic sheet A... Gap between male mold and male mold B... Fitting depth of male and female mold 1 Figure 2 eye

Claims (1)

[Claims] 1) A plastic sheet provided with ruled lines, in which the bottom wall of the ruled lines protrudes to one side of the plastic sheet, and the cross-sectional shape of the ruled lines is thicker at the center and thinner at both sides than at the center. A plastic sheet with ruled lines. 2) A method of attaching ruled lines by squeezing a plastic sheet with a male mold and a female mold, in which the width of the male mold is 2 to 4 times the thickness of the plastic sheet, and the gap between the male molds is made of plastic. A method for attaching ruled lines, characterized in that the thickness is 0.2 to 0.7 times the thickness of the plastic sheet, and the male mold is fitted into the female mold to a depth of 0.5 to 3 times the thickness of the plastic sheet.