JPS6067099A - Method of punching composite board - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention uses a uniaxially stretched plastic film (
The present invention relates to a rl punching method for a composite board having a composite plate (or a sheet).

For example, a polarizing plate is known as a composite plate having a uniaxially stretched plastic film as a surface material. The polarizing plate is generally made of a stretched hydrophilic polymer film containing iodine and/or
Or, it is composed of an iodine and/or dichroic substance-based polarizer in which a dichroic substance is adsorbed and oriented, and an optically transparent uniaxially stretched plastic film laminated on one or both sides of the polarizer. It is something that exists.

It is used in combination with a polarized polarizing liquid crystal display cell, but since the shape of a liquid crystal display cell is generally rectangular or square, the polarizing plate used therein is also punched into a rectangular or square shape. Ru.

However, the original fabric of the polarizing plate is in the form of a roll or a long plate with the stretching axis of the -axis stretched plastic film in the dredging direction. When punching, the two opposing sides are not parallel to the stretching axis of the film, which causes a problem in that cracks or bulges occur on the opposing two sides of the rectangular or rectangular polarizing plate.

Such cracks and cracks occur because the direction of the cutting blade substantially coincides with the direction of molecular orientation due to stretching of the film.

When the polarizing plate is mounted on a liquid crystal display cell, these cracks and cracks may be bent or scattered, and may enter between the two, making the thickness between the two uneven and reducing the display performance. In addition, when assembling a liquid crystal display cell using polarizing plates, it can get in between the polarizing plates, which are the cell substrates, making the cell thickness uneven and reducing display performance. It has the following drawback.

The present invention provides a novel composite plate punching method that is free of or has only a few cracks or cracks, and its gist is that a uniaxially stretched plastic film (or sheet) is used as the surface material. When punching out a composite plate having a film (or sheet) using a cutting blade including a straight portion, the straight portion of the cutting blade and the stretching axis of the film (or sheet) are perpendicular to each other.

According to the punching method of the present invention, the cutting blade enters at an angle to the film's stretching axis, so no cracks or burrs are recorded, and even if cracks or burrs occur in the temporary sheet, the cutting blade enters at an angle to the film's stretching axis. It has the characteristics of being strong and not prone to bending or scattering.

In addition to the polarizing plate composed of the above-mentioned polarizer and a plastic film (or sheet) stretched 3 to 6 times in the '-uniaxial direction, examples of the composite plate used in carrying out the present invention include, for example, paper, A uniaxially stretched plastic film (or sheet) is attached to one or both sides of a substrate such as woven fabric, non-woven fabric, metal foil, plastic film or sheet using adhesive means such as adhesive, welding, fusion, etc. toy,
This also includes composite boards that are punched out and used for daily necessities.

A cutting blade including a straight portion is attached to a cutting/punching device such as a blade cutter or a Thomson blade cutter. For composite plates, it is necessary to set the cutting blade or adjust the feeding direction of the composite plate so that the cutting blade and the stretching axis of the uniaxially stretched plastic film that makes up the composite plate are oblique to each other. be.

The oblique angle between the cutting blade and the stretching axis varies depending on the stretching ratio of the plastic film, etc., but when the stretching ratio is 3 to 3.
When the stretching ratio is 6 times, it is in the range of 2 to 7 degrees, preferably 2.5 to 5 degrees.According to experiments, even if the stretching ratio is 3 times or less, there is little effect if it is less than 2 degrees, and if it is more than 7 degrees, This is not preferable because the punched product has little separation and visibility is poor in the case of a polarizing plate.

Examples of the present invention will be shown below.

Example A polarizer (thickness: 30 μm) made of a stretched polyvinyl alcohol film with iodine adsorbed and oriented, had a thickness of 2 µm on both sides.
A polyester film (thickness: 100 μm) stretched 4 times in the uniaxial direction is bonded via an adhesive layer of 0 μm to obtain a polarizing plate having a total thickness of 270 μm.

This polarizing plate was punched out under the following conditions, and the crack generation rate and burr scattering rate were measured (n=16 pieces).

Equipment: Thomson blade cutter (blade angle 30 degrees) Punching pressure 200 to 9/cA Punching speed: 1000771/hr Punching conditions:
25°C x 60% R,H.

The measurement results are shown in Table 1.

Table 1 Calculation method in Table 1.

Crack occurrence rate: Number of cracks generated / total number x 100 (%) Paris scattering rate: number of burrs scattered / number of cracks x 100 (%) Patent applicant Nitto Electric Industry Co., Ltd. Representative Mibe Hijikata

Claims (1)

[Claims] When punching a composite plate having a uniaxially stretched plastic film (or sheet) as a surface material using a cutting blade including a straight part, the straight part of the cutting blade and the film (or sheet) A composite board punching method characterized by punching out a composite board with the drawing axis obliquely intersecting with the drawing axis. 2) Composite plate punching method 0 according to claim 1, wherein the oblique angle is 2.5 to 5 degrees.