Polyvinyl alcohol film, polarizing film and polarizing plate, and polyvinyl alcohol film production method

A polyvinyl alcohol-based and manufacturing method technology, which is applied to polarizing elements, flat products, optical elements, etc., can solve problems such as breakage productivity of polyvinyl alcohol-based films, achieve excellent swelling and stretchability, high polarizing performance, The effect of less chromaticity unevenness

Active Publication Date: 2019-10-29
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 film, polarizing film and polarizing plate, and polyvinyl alcohol film production method

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

A polyvinyl alcohol film which has an excellent balance of swelling properties and stretching properties during polarizing film manufacture, does not result in rupture during thin polarizing film production, and enables obtaining a polarizing film that exhibits high polarization performance and has few color irregularities, a polarizing film and polarizing plate using said polyvinyl alcohol film,and a polyvinyl alcohol film production method are provided. This polyvinyl alcohol film is elongate, and is characterized by satisfying expression (A) and (B) below. (A)... [delta]n(MD)Ave >= 2.2*10-3 (B)... [delta]n(TD)Ave >= 2.0*10-3 [delta]n(MD)Ave indicates the value obtained by averaging the length-direction birefringence in the thickness direction of the polyvinyl alcohol film, and [delta]n(TD)Ave indicates the value obtained by averaging the width-direction birefringence 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 Applications(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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