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Polyvinyl alcohol-based film, polarizing film and polarizing plate, and method for producing polyvinyl alcohol-based film

A technology of polyvinyl alcohol-based and manufacturing methods, applied to polarizing elements, optical elements, flat products, etc., can solve the problems of polyvinyl alcohol-based film rupture productivity, etc., achieve excellent swelling and stretchability, and appropriate birefringence , The effect of less chromaticity unevenness

Active Publication Date: 2022-03-08
MITSUBISHI CHEM CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, this thin polyvinyl alcohol-based film has problems in productivity such as cracks due to stretching during the production of polarizing films.

Method used

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  • Polyvinyl alcohol-based film, polarizing film and polarizing plate, and method for producing polyvinyl alcohol-based film

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0179] (Production of polyvinyl alcohol-based film)

[0180] In a 5000L dissolving tank, add 1000kg of polyvinyl alcohol-based resin with a weight average molecular weight of 142000 and a saponification degree of 99.8 mol%, 2500kg of water, 105kg of glycerin as a plasticizer, and 0.25kg of polyoxyethylene laurylamine as a surfactant, It heated up to 150 degreeC, carried out pressure-dissolution with stirring, and adjusted the concentration to obtain the aqueous solution of the polyvinyl-alcohol-type resin with a resin density|concentration of 25 weight%. Then, after supplying the polyvinyl alcohol-based resin aqueous solution to a twin-screw extruder for defoaming, the temperature of the aqueous solution was set at 95° C., and it was discharged from a discharge port of a T-shaped slot die (discharge speed 1.3 m / min) and cast onto the surface. Film formation was performed on a casting drum at a temperature of 80°C. The formed film was peeled from the casting drum, and was drie...

Embodiment 2

[0185] In Example 1, the polyvinyl alcohol-based resin aqueous solution was discharged (discharge speed 1.9m / min) and cast to a casting drum with a surface temperature of 88°C to form a film, and the same procedure as in Example 1 was performed. , and a film (width 2 m, thickness 45 μm) having a water content of 10% by weight was obtained. Then, in the same manner as in Example 1, the film was stretched 1.2 times in the width direction (TD) at 80°C using a stretcher, and then transported in a dryer at 135°C with a fixed width of 2.4m to obtain a polyvinyl alcohol-based film. Film (width 2.4 m, thickness 35 μm, length 2 km). The properties of the obtained polyvinyl alcohol-based film are shown in Table 1 below.

[0186] Moreover, using the said polyvinyl-alcohol-type film, it carried out similarly to Example 1, and obtained the polarizing film and the polarizing plate. In the swelling step during the production of the polarizing film, the above-mentioned polyvinyl alcohol-bas...

Embodiment 3

[0188] In Example 1, except that the discharge speed at the time of film formation was set to 0.8 m / min, and film formation was carried out by discharge and casting, it was carried out in the same manner as in Example 1, and a moisture content of 5% by weight was obtained. film (width 2m, thickness 20μm). Then, in the same manner as in Example 1, the film was stretched 1.4 times in the width direction (TD) at 80°C using a stretcher, and then transported in a dryer at 130°C with a fixed width of 2.8m to obtain a polyvinyl alcohol-based film. Film (width 2.8 m, thickness 14 μm, length 2 km). The properties of the obtained polyvinyl alcohol-based film are shown in Table 1 below.

[0189] Moreover, using the said polyvinyl-alcohol-type film, it carried out similarly to Example 1, and obtained the polarizing film and the polarizing plate. In the swelling step during the production of the polarizing film, the above-mentioned polyvinyl alcohol-based film did not generate creases or...

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Abstract

The present invention provides a polyvinyl alcohol-based film that is excellent in balance between swelling and stretchability during production of a polarizing film, exhibits high polarization performance and exhibits uneven chromaticity without cracking during production of a thin polarizing film The present invention provides a polarizing film and a polarizing plate using the polyvinyl alcohol-based film, and a method for producing the above-mentioned polyvinyl alcohol-based film. The polyvinyl alcohol-based film of the present invention is a strip-shaped polyvinyl alcohol-based film, which is characterized in that it meets the following formulas (A) and (B): Δn(MD)Ave≥2.2×10 ‑3 …(A)Δn(TD)Ave≥2.0×10 ‑3 ...(B). The above-mentioned Δn(MD)Ave is a value obtained by averaging the birefringence in the longitudinal direction in the thickness direction in the polyvinyl alcohol-based film, and the above-mentioned Δn(TD)Ave is a value representing the birefringence in the width direction A value obtained by averaging in the thickness direction.

Description

technical field [0001] The present invention relates to a polyvinyl alcohol-based film as a material for forming a polarizing film having excellent dyeability, a high degree of polarization, and less unevenness in chromaticity, and to a polarizing film and a polarizing plate using the polyvinyl alcohol-based film, And the manufacturing method of the said polyvinyl-alcohol-type film. Background technique [0002] Conventionally, polyvinyl alcohol-based films have been used in many applications as films excellent in transparency, and one of such useful applications includes polarizing films. This polarizing film is used as a basic component of a liquid crystal display, and its use has spread to devices requiring high quality and high reliability in recent years. [0003] Under such circumstances, along with the increase in luminance, high definition, large area, and thinning of screens such as liquid crystal televisions and multifunctional mobile terminals, polarizing films w...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G02B5/30B29C55/08C08J5/18B29K29/00B29L7/00B29L11/00
CPCB29C55/08C08J5/18G02B5/30C08J2329/04
Inventor 清水俊宏北村秀一寺本裕一
Owner MITSUBISHI CHEM CORP
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