JP2541253B2 - Plastic sheet with folding line - Google Patents

Description

TECHNICAL FIELD The present invention relates to a plastic sheet having a fold line.

(Prior art) Bending a plastic sheet, doll case,
When processing into packaging containers, etc., a ruled line for bending is attached and the process is performed along this ruled line.

In the conventional plastic sheet with a folding line, the formed folding line has, for example, a groove 11 which is recessed in the thickness direction of the plastic sheet 2 as shown in the perspective view of FIG. The bottom of the groove 11 was flat. This plastic sheet with fold lines is not affected by the stress generated in the fold line on the flat surface adjacent to the fold part after the fold part recovers its shape due to elasticity and is not finished at a predetermined angle when it is bent. There was a problem that it was easy to bend. Therefore, the applicant of the present invention previously proposed a groove or an interrupt hole provided at the bottom of the bent line. (Actual application Sho 61
No. 186289, Japanese Patent Application No. 62-196104) (Problems to be solved by the invention) However, although the above-mentioned conventional plastic sheet with a folding line has a good foldability, a box for storing a heavy load, In the case of a box in which the number of times of folding is increased by opening and closing, there is a dislike that the box is easily broken from the folding line.

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

FIG. 1 is an enlarged perspective view showing an example of a plastic sheet with folding lines according to the present invention, and FIG. 2 is a sectional view taken along the line II-II of FIG. 1 and an example of an apparatus for producing a plastic sheet with folding lines. Sectional view, FIG. 3 is of FIG.
III-III sectional view and a partial sectional view of an apparatus for producing a plastic sheet with folding lines, FIG. 4 is an enlarged perspective view showing another example of the plastic sheet with folding lines, and FIG. 5 is a conventional folding It is a perspective view showing an example of a lined plastic sheet.

As shown in FIGS. 1 to 4, in the present invention, in the plastic sheet 2 containing the bending line 1, the bending line is formed in the longitudinal direction by a shallow groove 3 and a deep groove 4 or a cut 5.
And a reinforcing rib 6 is formed at the boundary between the shallow concave groove and the deep concave groove or cut, and a plastic sheet with a folding line.

As the plastic sheet 2, a hard sheet such as polyvinyl chloride or polypropylene can be used. Usually, the thickness can be about 0.1 to 1.0 mm.

As the bending line 1, as shown in FIGS. 1 to 4, a plastic sheet 2 having a groove formed on the surface thereof to facilitate bending is used. Although not shown, an appropriate shape can be used, such as one provided with a plurality of grooves in the range of the bending line.

The cross-sectional shape of the grooves 3, 4 or the cut 5 may be trapezoidal as shown in FIG. 3, but is not limited to this.

The depth A and the width B of the shallow groove 3 can be appropriately set depending on the material and thickness of the plastic sheet 2, for example, the thickness 0.25.
Taking the case of a rigid polyvinyl chloride sheet of mm as an example,
The depth A is preferably 0.10 to 0.20 mm, and the width B is preferably 0.15 to 0.75 mm.

The deep groove 4 or the cut 5 may be formed along the length direction of the bending line 1. The deep grooves 4 or the cuts 5 disperse and equalize the strain generated in the bending line 1 in the lengthwise direction to prevent bending and the like due to local stress concentration and prevent shape recovery due to elasticity. It is a thing. The shape of the deep groove 4 or the cut 5 is not particularly limited, but for example, the thickness of the plastic sheet 2 is 0.25 mm.
In this case, as shown in FIG. 2, depending on the size of the concave groove 3, the length C of the opening can be suitably set to 0.1 to 2 mm and the interval D can be suitably set to 0.3 to 3 mm.

The reinforcing ribs 6 have a shallow groove 3 and a deep groove 4 or a cut 5.
It may be formed at the boundary between the groove, that is, at the front and rear ends of the groove over the width direction of the groove. When the reinforcing rib is bent from the bending line, the stress in the tearing direction triggered by the deep groove 4 or the cut 5 is prevented from being transmitted to the shallow groove 3, so that the sheet in the shallow groove is not easily broken. Therefore, it is considered that the entire bending line is not broken. The height of the reinforcing rib 6 is basically the shallow groove 3.
It suffices to stand on the upper surface of the sheet, but it may be flush with the sheet surface as shown in FIG. The width E of the reinforcing rib 6 is
It is preferable that the thickness L of the plastic sheet is 30% to 500% because the reinforcing effect is particularly high and the bendability is not impaired.

In order to manufacture the plastic sheet of the present invention, for example, as shown in FIGS. 2 and 3, the cutting edge is intermittently cut out to form a concave portion 31 and a convex portion 41. By bending the plastic sheet 2 by bending the ruled line blade 9 notched in the width direction and forming the lateral groove 61 and the flat pedestal 10, the recess 31 is formed on the surface of the plastic sheet.
The shallow groove 3 corresponding to the above, the deep concave groove 4 or the cut 5 corresponding to the protrusion 41, and the reinforcing rib 6 corresponding to the lateral groove 61 are simultaneously formed. At this time, even if the break is not completely open, it can be opened by bending. Further, the ruled line blade 9 and the pedestal 10 may be heated.

The edge angle F of this ruled line blade is 30 to 130 degrees, and the tip width G is 0.5.
It is preferably not more than mm.

(Effect of the invention) The present invention is a plastic sheet containing a fold line, wherein the fold line is formed with a shallow groove and a deep groove or a slit alternately in the length direction thereof, and the shallow groove and the deep groove. Since it is a plastic sheet with a folding line characterized by forming a reinforcing rib at the boundary with the groove or cut, the strain and elastic force generated at the time of bending are dispersed in the length direction of the groove to be uniform and small. So
Not only is the bending angle accurate, and the flatness after assembly is good, but the folding line is not easily broken even when used in a box for storing heavy items or a box that opens and closes many times.

[Brief description of drawings]

FIG. 1 is an enlarged perspective view showing an example of a plastic sheet with folding lines according to the present invention, and FIG. 2 is a sectional view taken along the line II-II of FIG. 1 and an example of an apparatus for producing a plastic sheet with folding lines. Sectional view, Fig. 3 is II of Fig. 1.
I-III cross-sectional view and a partial cross-sectional view showing an example of an apparatus for producing a plastic sheet with folding lines, FIG. 4 is an enlarged perspective view showing another example of the plastic sheet with folding lines, and FIG. It is a perspective view which shows an example of the conventional plastic sheet with a folding line. 1 ... Bending line 2 ... Plastic sheet 3 ... Shallow groove, 4 ... Deep groove 5 ... Break, 6 ... Reinforcing rib

Claims (1)

(57) [Claims] 1. A plastic sheet containing a fold line, wherein the fold line is formed by alternately forming a shallow groove and a deep groove or a cut in the length direction, and the shallow groove and the deep groove or a cut. A plastic sheet with a folding line, characterized in that reinforcing ribs are formed at the boundaries of the.