JP3000387B2 - Plastic sheet with folded lines - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a plastic sheet with a folded crease.

(Conventional technology) A plastic sheet is folded and processed into a doll case,
When used in a packaging container or the like, a folding ruled line is provided, and bending is performed along the folding ruled line.

Conventionally, as the folding ruled line, one having an uneven shape intermittent in the longitudinal direction to facilitate bending (Japanese Patent Application Laid-Open No. 1-141720), and a combination of a shallow concave groove and a deep concave groove (Japanese Patent Application Laid-Open No. No. 150520) has been proposed.

(Problems to be Solved by the Invention) In the case of the conventional folding ruled line composed of a combination of simple concavities and convexities, there is a tendency that the deeper the groove is, the easier it is to bend and the easier it is to be broken. There is a problem that extremely high precision is required for the depth to be formed.

(Means for Solving the Problems) The present invention has been made to solve the above problems, and the gist of the present invention is to provide a plastic sheet with a folding ruled line by forming the folding ruled lines into short grooves or grooves having different opening widths on the sheet surface. A plastic sheet with a folding ruled line formed by combining cuts in the length direction.

 Hereinafter, the present invention will be described with reference to the accompanying drawings.

FIG. 1 is a perspective view showing an example of a folded creasing plastic sheet of the present invention, FIG. 2 is a sectional view taken along the line II-II of FIG. 1, FIG. 3 is a sectional view taken along the line III-III of FIG. Is a perspective view showing another example of the plastic sheet with a folding ruled line according to the present invention, and FIG. 5 is a sectional view taken along line VV of FIG.

According to the present invention, as shown in FIGS. 1 to 4, a folding ruled line 2 is formed on a plastic sheet 1. The feature of the folded ruled line 2 is that different types of short concave grooves 31, 32, 33 are formed.
Or in the point formed by combining the cut 34 in the length direction, by appropriately selecting the combination,
It is possible to obtain a plastic sheet with a folding ruled line that is highly foldable according to the physical properties and thickness of the plastic sheet 1 and is hard to be broken.

The type of the groove referred to in the present invention is not limited to simply changing the depth, but for example, as shown in FIG. 1 to FIG. 4, the opening width W1 of the opening formed on the surface of the plastic sheet 1 is wide and shallow. Combinations of 31, 33 and openings 32, 34 having a narrow and deep opening width W2, or a combination of two parallel grooves as shown in FIG. 4 and having a substantially W-shaped cross section 33 And a combination of a simple cut 34, or a combination of three parallel concave grooves (not shown), a concave groove with small irregularities formed on the inner surface, or the like (not shown).

 Next, the example of FIGS. 1 to 3 will be described in detail.

In this example, as shown in FIG. 2, the opening width W1 of the opening formed on the surface of the plastic sheet 1 is large and shallow.
3, and deep grooves 32 having a narrow opening width W2 and deep as shown in FIG. 3 are alternately arranged adjacent to each other as shown in FIG.

Since the concave groove 31 is shallow, the plastic sheet 1 in this portion is thick and hard to tear, and the opening width is smaller than that of the adjacent concave groove 32.
Since W1 is wide, the stress of strain generated by bending is dispersed over this wide width, so that bending is easy, and breakage due to stress concentration is unlikely to occur. Length L1 of each groove 31
Is preferably in the range of 0.5 to 10 times the thickness T of the plastic sheet 1 because the effect that tearing hardly occurs and that the sheet is easily bent is further enhanced.

Since the opening width W2 of the concave groove 32 is narrower than that of the concave groove 31, the stress at the time of bending is absorbed within the width of the concave groove 31, and the possibility of breakage is small. Further, since the concave groove 32 has a large depth, there is an effect that it is easy to bend. The depth H2 of the concave groove 32 is preferably 80% or more of the thickness T of the plastic sheet 1 because it is extremely easy to bend. If the groove is completely cut, it becomes easy to be stained before bending, so it is preferable to make the groove a not cut.

In FIGS. 2 and 3, after the formed ruled line is completely bent in the direction of arrow 6, when the cage is returned, the groove 31 becomes a dotted line 31 in FIG.
As shown in FIG. 1, the opening width further increases and becomes thinner, and as shown in FIG.
Since it is deformed as shown by, it becomes extremely easy to bend. In order to improve the bendability by folding once, it is necessary to select a plastic sheet 1 having an elongation percentage of 100% or more when broken at 23 ° C. If the elongation is 100% or less, the ruled line is easily broken by bending once. As the plastic sheet 1, a polyethylene terephthalate sheet having a crystallinity of 5% or less is preferable.

 Next, an example shown in FIGS. 4 and 5 will be described.

The concave groove 33 has a wide opening width W1 and is formed of two parallel concave grooves, and has a substantially W-shaped cross section as shown in FIG. And since the thickness of the central part is large, it is hard to tear.

Since the opening width W2 of the cut 34 is narrow, the longitudinal end of the cut 34 is continuous with the thick portion at the center of the adjacent groove 33.

Since the concave grooves 33 and the cuts 34 are alternately arranged adjacent to each other, they are extremely easy to bend by the cuts 34 and are effectively reinforced by the central portion of the concave grooves 33, so that they are not easily broken.

Further, also in the process of forming the ruled line, when pressurized by the ruled line blade, a force for expanding the cut 34 as shown by an arrow 71 is exerted by the wedge effect of the ruled line blade, while the adjacent groove 33 is formed as shown in FIG. As shown by the arrow 72, a compressing / contracting force acts on the central portion and cancels out the pushing / expanding force, so that there is an effect that there is little possibility of breaking even if pressed deeply.

(Effect of the Invention) The present invention relates to a plastic sheet containing a folding ruled line, wherein the folding ruled line is formed by combining short grooves or cuts of different types in the length direction. As a result, it is possible to obtain a folded ruled sheet having a high balance between ease of folding and resistance to tearing while the combined grooves or cuts complement each other.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an example of a folded creasing-lined plastic sheet of the present invention, FIG. 2 is a sectional view taken along the line II-II of FIG.
FIG. 3 is a cross-sectional view taken along the line III-III of FIG. 1, FIG. 4 is a perspective view showing another example of the plastic sheet with folded creases of the present invention, and FIG. 5 is a cross-sectional view taken along the line VV of FIG. . 1 ... Plastic sheet, 2 ... Bending ruled line, 31,3
2,33 …… grooves, 34 …… cuts.

Claims (1)

(57) [Claims] 1. A plastic sheet containing a folding ruled line, wherein the folding ruled line is formed by combining short grooves or cuts having different opening widths on the sheet surface in the length direction of the ruled line. .