JPS63281965A - Sheet like article having rib like pattern imparted thereto - Google Patents

Abstract

PURPOSE:To provide a sheet like article having a rib like pattern still more improved from the aspect of strength, rigidity and material cost, by forming ribs arranged at random so as to cross each other at a right angle or obliquely at some selected interval values. CONSTITUTION:A rib structure is constituted of a large number of ribs 3 formed to the surface thereof and shows such a pattern that a mode wherein the ribs 3 cross each other crosswise at right angles is repeatedly spread or such a pattern that a mode wherein the ribs 3 obliquely cross each other crosswise is repeatedly spread. The ribs 3 of the structure 2 are arranged at some selected interval values at random so that the frequency of each interval value becomes uniform over the whole of a sheet. The height (h) of each rib of said structure is pref. 0.15-0.5 mm and the width (l) of the rib thereof is pref. 0.2-1.5 mm. An interval (p) is pref. 0.8-20.0 mm. This sheet like article is composed of a synthetic resin or engineering plastic of every kind and the rear surface thereof is pref. a printable transparent smooth surface.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a sheet-like article provided with a rib-like pattern. The sheet-like product of the present invention can be used as a packaging material or a decorative material to make various cases such as VTR cassette tape cases and stationery covers.

(Prior Art) Cases for VTR cassette tapes that are currently widely available on the market include those made of paper and those made of synthetic resin. The cassette tape case made of paper has drawbacks such as low strength and inferior structure, the generation of harmful paper dust, and a lack of a luxurious feel. In contrast,
The cassette tape case made of synthetic resin is superior to that made of paper because it has much higher strength and gives a more luxurious feel to the purchaser. Furthermore, a cassette tape case made of synthetic resin is advantageous in that the case itself can be made transparent by using a transparent resin.

(Problem to be Solved by the Invention) However, conventional synthetic resin VTR cassette tape cases generally have high material costs, making them considerably more expensive than paper cases, which is disadvantageous in terms of price competitiveness. There was a problem.

Therefore, while maintaining excellent properties such as structural strength,
It has been desired to develop a synthetic resin VTR cassette tape case that can reduce production costs.

In consideration of the above-mentioned circumstances, and as a result of intensive research on synthetic resin sheets processed into VTR cassette tape cases, the present inventor has developed a synthetic resin sheet-like product as disclosed in a patent application dated the same date as the present application. We have developed a rib structure with a continuous pattern of ribs intersecting each other or crisscrossing on the surface. This new sheet-like product is an excellent product that achieves both improved strength (rigidity) and thinner walls.

However, if the riffs of the rib structure are arranged at regular intervals in the vertical and horizontal directions, the intersecting parts of the rib structure, where stress is concentrated during bending, will be aligned in a straight line. Therefore, it cannot be expected that the strength and rigidity will be sufficiently improved.

As a countermeasure to this problem, is it possible to attach and form a reinforcing structure to the above-mentioned intersection part as disclosed in the above patent application to strengthen it? There is a need for highly rigid sheet-like materials that are free from scratches.

The present invention has been made to solve this problem, and an object of the present invention is to provide a sheet-like product having a rib-like pattern that is further improved in terms of strength, rigidity, and material cost.

(Means for Solving the Problems) The sheet-like article provided with a rib-like pattern of the present invention is made of synthetic resin, and has a continuous pattern on the surface of the sheet body that is perpendicular or diagonal between the ribs or cross-shaped. The rib structure is characterized in that each rib of the structure is randomly arranged at a selected spacing value.

The sheet material of the present invention may be made of synthetic resin such as polyvinyl chloride, polypropylene, and various engineering plastics, and materials conventionally used for cases such as VTR cassette tape cases may be used. Can be done. This sheet-like material preferably has a smooth surface on which the surface opposite to the surface on which the rib structure is formed is capable of normal printing, and the sheet-like material is preferably a transparent resin product.

The rib structure according to the present invention is composed of a large number of ribs on the surface of the sheet body, and has a pattern in which the ribs repeatedly extend orthogonally in a cross shape (orthogonal cross continuous pattern) or a pattern in which the ribs cross each other diagonally in a cross shape. Any structure may be used as long as the structure exhibits a repeating pattern (continuous diagonal cross pattern), and each rib of the rib structure is arranged randomly at a number of selected spacing values, preferably with a frequency of each spacing value. are arranged evenly across the sheet. for example,
It is preferable to arrange the ribs so that the five intervals of 2 mm, 3 mm, 4 mm, 5 mm, and 6 mm are arranged in order so that the intervals are disorderly like a random number table and the frequency is uniform throughout. The interval values and number selected are arbitrary.

Further, the height of each rib of the rib structure is 0.15 to 9
．． Preferably, it is 5 mm. If it is less than 0.15 mm, a sufficient effect of reducing the area weight cannot be obtained, while if it exceeds 0.5 mm, the strength of the entire sheet-like article will be significantly reduced. In addition, the width of each rib of the same structure is 0.2 to 1.5 mm.
It is preferable that If it is less than 0.2 mm, no significant strength improvement effect can be obtained; on the other hand, if it exceeds 1.5 mm,
Furthermore, it is preferable that the interval between each rib is 0.8 to 20.0 mm, since a satisfactory effect of reducing the area weight cannot be achieved. If it is less than 0.8 mm, hardly any effect of reducing the area weight can be obtained, while if it exceeds 20.0 mm, a satisfactory strength improvement effect cannot be achieved.

Conventional sheets have been made by extruding synthetic resin into a sheet through a T-die and then stretching the sheet. On the other hand, by preparing an embossing roll with a rib structure expressing the above-mentioned pattern and a surface shape that matches the shape of the artifact, and passing the synthetic resin between the roll and a smooth roll, a so-called roll separation method is used. Manufactured by.

Thereafter, the sheet-like material of the present invention is subjected to bending processing and the like according to a conventional method to be finished into a case product such as a VTR cassette tape case.

(Function) In the sheet-like article of the present invention, since the ribs are arranged randomly at several spacing values, the intersections of the rib structure where stress is concentrated during bending or twisting are not aligned in a straight line. Therefore, the product of the present invention has significantly improved strength and rigidity, and is extremely difficult to deform, compared to a sheet-like product that exhibits the same continuous cross pattern but has ribs arranged regularly at equal intervals.

Furthermore, the sheet material of the present invention has a greatly reduced basis weight (sheet weight per In") compared to a flat sheet of the same thickness due to the riff-like pattern, and the amount of resin used is greatly reduced. be able to.

(Example) Embodiments of the present invention will be described below with reference to the drawings.

As shown in FIG. 1, the sheet-like article of this example forms a rib structure 2 on the surface of the sheet main body l in which pattern units in which ribs 3 intersect orthogonally in a cross shape are two-dimensionally wide. It will be done. The intersecting portion 4 of the rib structure 2 is shown enlarged in FIG. 2, in which the width of the rib 3 and h represent the height of the rib 3.

The sheet-like material of the example has ribs 3 of 2 mm, 3 mm, and 4 mm in length and width directions, respectively.
The spacing values are selected from the group consisting of mm, 5 mm, and 6 mm, and are arranged randomly and in the order shown in a random number table so that the frequency is uniform throughout. In FIG. 1, P o, P 1. Pt
...Pn, ... (subscript n represents an integer) represents the distance between the riff 3 and the adjacent rib 3.

The sheet-like material of this example is produced by passing polypropylene or the like between an embossing roll having the above-mentioned pattern and a smooth roll.

For comparison, rib 3... is 6 m in the vertical and horizontal directions.
A sheet-like product similar to the sheet-like product of Example was produced except that the sheets were regularly arranged at equal intervals of m. Furthermore, a flat sheet having the same thickness as in the example was produced by extrusion forming and stretching.

For each of these champion sheet-like products, the moment of inertia was calculated, and the bending rigidity was measured according to a conventional method.For the sheet-like products of the example, the reduction rate in area weight was determined based on the flat sheet of the comparative example. . As a result,
The sheet material of the example has a basis weight that is several percent lower than the flat sheet of the comparative example, and unlike the sheet of the comparative example in which the ribs are arranged regularly at equal intervals, it is difficult to undergo bending deformation and has low bending rigidity. It was confirmed that the sheet was significantly improved compared to the comparative example sheet.

(Effects of the Invention) As explained above, the sheet material provided with the rib-like pattern of the present invention exhibits a continuous cross-shaped pattern or has a disordered arrangement of the ribs, so that the ribs are arranged at equal intervals. Compared to regular sheets of the same type, strength and rigidity are significantly improved. Moreover, in the sheet-like article of the present invention, by forming the rib-like structure, the amount of resin used can be reduced, and the cost of the sheet material can be reduced. Therefore, according to the present invention, after appropriate processing, it is possible to provide a sheet product that is further improved in terms of structural strength, manufacturing cost, etc.

[Brief explanation of the drawing]

FIG. 1 is a plan view showing the surface of a sheet-like article according to an embodiment of the present invention, and FIG. 2 is an enlarged perspective view showing the vicinity of the intersection of the sheet-like article shown in FIG. 1. In the figure, l... Seat body 2... Rib structure 3... Rib 4... Intersection text... Rib width h... Rib height Po, Ps, Pz" p n, ""... Interval between ribs

Claims (1)

[Claims] It is made of synthetic resin, and has a rib structure formed on the surface of the sheet body in a continuous pattern in which the ribs intersect perpendicularly or diagonally in a cross shape, and each rib of the structure is made of a selected number of ribs. A sheet-like material provided with a rib-like pattern, characterized in that it is randomly arranged at intervals.