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Polyester film for mold release film

A technology of polyester film and mold release film, applied in the field of polyester film, can solve problems such as influence detection, foreign matter mixing, and bright spots in the adhesive material layer.

Active Publication Date: 2007-01-03
MITSUBISHI CHEM CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Here, polarizers are made of a polyester film provided with a release layer through an adhesive layer, and the crossed Nicol prism detection is performed with the release polyester film sandwiched between two polarizers. Usually, In the case of using a release polyester film for this technical proposal, there may be disadvantages such as interference with crossed Nicol prism method, easy to miss foreign matter, defects, etc.
In addition, if there are foreign substances or defects in the polyester film, it is impossible to judge whether the polarizing plate is defective, and there are cases where the polarizing plate becomes a defective product. Therefore, the defective rate may increase when the polarizing plate is manufactured.
[0005] In addition, especially in the release film bonded to the polarizing plate used in large TVs, the polyester oligomers present in the polyester film migrate to the adhesive material layer, and after a period of time, the adhesive layer becomes weaker. Issues with bright spots in material layers
[0006] Existing biaxially oriented polyester films for release films have been disclosed: polyester films with a prescribed amount of low-molecular-weight substances precipitated from the surface (for example, refer to Patent Document 1); polyester films with prescribed orientation angles of the film (for example, refer to Patent Document 1). Document 2), but even if these polyester films are used, there are problems in the detection of defects that are definitely found.
In addition, a technical solution to reduce the amount of polyester oligomers precipitated from the surface by providing a coating layer is disclosed (for example, refer to Patent Document 3), but so far, no attention has been paid to the existence of small coating layer defects on the surface and the resulting defects. Occurrence of local precipitation of polyester oligomers

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0091] (manufacturing of polyester film)

[0092] According to the proportions shown in Table 1, the above-mentioned polyesters A to D were used as the mixed raw materials of A layer and B layer, respectively supplied to two twin-screw extruders, melted at 285 ° C, and then A layer was used as the final material. The outer layer (surface layer), with the B layer as the middle layer, forms two kinds of three-layer structures with a thickness ratio of A layer / B layer / A layer=10% / 80% / 10% relative to the total thickness, after cooling to 20 ℃ co-extruded on the die-casting drum, and then cooled and solidified to obtain random flakes. Then, after stretching 2.8 times in the longitudinal direction at 100°C, apply the water-dispersed coating liquid A whose solid content concentration is adjusted to 2.5% as shown below, so that the coating thickness after stretching and drying becomes 0.05 μm, and then, After the preheating process in the tenter, 5.4 times of transverse stretching at...

Embodiment 2

[0098] Raw material ratios and film forming conditions are as shown in Table 1, except that the water dispersion coating liquid A whose solid content concentration was adjusted to 3% by weight was used, and the production was carried out in the same manner as in Example 1 to obtain a polyester film. The results of the obtained polyester film are shown in Table 1, and it is a film suitable for practical use.

Embodiment 3

[0100] Raw material ratios and film forming conditions are as shown in Table 1, except that the water-dispersed coating liquid A whose solid content concentration was adjusted to 1% by weight was used, and the production was carried out in the same manner as in Example 1 to obtain a polyester film. The results of the obtained polyester film are shown in Table 1, and it is a film suitable for practical use.

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Abstract

The present invention provides a polyester film for release film which makes it possible to conduct accurate inspections of polarizing plates by the crossed nicols method and can also inhibit transfer of the polyester oligomers into the adhesive layer. A polyester film for release film having a coating layer on at least one surface thereof with defects of not more than 50 per m2, which polyester film has such properties that the amount of polyester oligomers extracted from the surface of said coating layer after 10-minute heat treatment at 150° C. is not more than 0.3 mg / m2, and the inclination of the principal axis of orientation (angle of orientation) of the film is not more than 8°; a release film for polarizing plate comprising the above-said film and a release layer provided thereon; and a polyester film for polarizing plate protective film comprising the above-said film.

Description

technical field [0001] The present invention relates to a polyester film excellent in optical properties which are important characteristics in films for liquid crystal displays, etc., and particularly relates to a polyester film suitable for use as a release film for a polarizing plate or a protective film for a polarizing plate. Background technique [0002] In recent years, with the rapid popularization of mobile phones and personal computers, compared with the existing CRT monitors, the demand for liquid crystal displays (LCDs) that can achieve thinness, lightness, power saving, and high image quality has increased significantly, and the large-screen technology of LCDs has also increased. significant development. As an example of a large screen of an LCD, recently, LCDs are used for applications such as a large monitor of 17 inches or more, a large TV, and the like. In many cases, large-screen LCDs are obtained by increasing the brightness of the backlight built in the ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B32B27/36B32B27/00C08J7/043C08J7/044C08J7/046C09J7/02
CPCB32B2250/244C08J7/047B32B2307/42B32B27/08C08J2367/02C09J2467/006C09J7/0235B32B27/36B32B2307/712B32B2457/202B32B2307/748C09J7/405Y10T428/31786C08J7/0427C08J7/043C08J7/046C08J7/044B32B2457/20
Inventor 奥村博辉
Owner MITSUBISHI CHEM CORP