Cellulose acylate film and method for producing same, and retardation film, polarizer and liquid crystal display device comprising the film

Abstract

A cellulose acylate film satisfying Re = 40 is produced by transporting a cellulose acylate film having a substitution degree of acyl substituted for hydroxyl group of cellulose of 2.88 or higher, and subjecting the film to heat treatment at 160 DEG C or higher.

Description

technical field

[0001] The present invention relates to a cellulose acylate film having optical anisotropy and capable of being directly bonded to a polarizer and a method for producing the same, and also relates to a retardation film, a polarizing plate, and a liquid crystal using the cellulose acylate film display device. Background technique

[0002] Polymer films represented by cellulose ester, polyester, polycarbonate, cycloolefin polymer, vinyl polymer or polyimide are used in silver halide photographic photosensitive materials, retardation films, polarizers and image display devices middle. Since films superior in surface smoothness and uniformity can be produced from these polymers, they are widely used for optical films.

[0003] Among them, a cellulose ester film having suitable moisture permeability can be directly bonded to the most commonly used polarizer made of polyvinyl alcohol (PVA) / iodine in an on-line manner. Therefore, cellulose acylate, especially cel...

Examples

preparation example Construction

[0078] As for the production method of cellulose acylate, its basic principle is described in Wood Chemistry by Nobuhiko Migita et al., pp. 180-190 (Kyoritsu Publishing, 1968). A representative method for producing cellulose acylate is a liquid-phase acylation method using a carboxylic anhydride-carboxylic acid-sulfuric acid catalyst. Specifically, cellulose raw materials such as cotton pulp or wood pulp are pretreated with an appropriate amount of carboxylic acid such as acetic acid, and then placed in a pre-cooled acylation mixture for esterification, thereby preparing complete cellulose acylate (2- , 3- and 6-positions of the acyl total substitution degree is close to 3.00). The acylation mixture generally contains a carboxylic acid as a solvent, a carboxylic anhydride as an esterification agent, and sulfuric acid as a catalyst. Typically, the amount of carboxylic anhydride used in the process is in stoichiometric excess relative to the total amount of water present in the...

Embodiment 101-118

[0229] [Example 101-118, Comparative Example 101-103]

[0230] (preparation of polymer solution)

[0231] 1) Cellulose acylate:

[0232] In each of Examples and Comparative Examples, cellulose acylate A to F described later was used according to Table 1. Each cellulose acylate was heated and dried at 120°C so that the water content was 0.5% by mass or less. After that, 15 parts by mass of cellulose acylate was used.

[0233] Cellulose acylate A:

[0234] Cellulose acetate powder from pulp with a degree of substitution of 2.91 was used. The viscosity-average degree of polymerization of cellulose acylate A was 270, and the degree of substitution of 6-acetyl group thereof was 0.93. The average diameter of the powder particles is 1.5 mm with a standard deviation of 0.5 mm.

[0235] Cellulose acylate B:

[0236] Cellulose acetate powder from pulp with a degree of substitution of 2.94 was used. The viscosity-average degree of polymerization of cellulose acylate B was 300, an...

Embodiment 151

[0299] (re-stretching of film)

[0300] The stretching was carried out by holding both ends of the cellulose acylate film in Example 113 with tenter clips to stretch the film in a direction perpendicular to the conveying direction in the heating zone. The temperature in the heating zone was 160°C and the draw ratio was 25%. The stretching ratio of the film was obtained according to the following formula in such a manner that the gauge lines of the film were set at constant intervals in a direction parallel to the conveying direction of the film, and the interval was measured before and after stretching.

[0301] Stretch ratio of the film (%) = 100 × {(the distance between the ruler and gauge lines after stretching)-(the distance between the ruler and gauge lines before stretching)} / the distance between the ruler and gauge lines before stretching

[0302] Re and Rth values ​​of the obtained thin film were measured, whereby Re = 160 nm and Rth = -2 nm were obtained. The slow p...

technical field

[0001] The present invention relates to a cellulose acylate film having optical anisotropy and capable of being directly bonded to a polarizer and a method for producing the same, and also relates to a retardation film, a polarizing plate, and a liquid crystal using the cellulose acylate film display device. Background technique

[0002] Polymer films represented by cellulose ester, polyester, polycarbonate, cycloolefin polymer, vinyl polymer or polyimide are used in silver halide photographic photosensitive materials, retardation films, polarizers and image display devices middle. Since films superior in surface smoothness and uniformity can be produced from these polymers, they are widely used for optical films.

[0003] Among them, a cellulose ester film having suitable moisture permeability can be directly bonded to the most commonly used polarizer made of polyvinyl alcohol (PVA) / iodine in an on-line manner. Therefore, cellulose acylate, especially cel...

Examples

preparation example Construction

[0078] As for the production method of cellulose acylate, its basic principle is described in Wood Chemistry by Nobuhiko Migita et al., pp. 180-190 (Kyoritsu Publishing, 1968). A representative method for producing cellulose acylate is a liquid-phase acylation method using a carboxylic anhydride-carboxylic acid-sulfuric acid catalyst. Specifically, cellulose raw materials such as cotton pulp or wood pulp are pretreated with an appropriate amount of carboxylic acid such as acetic acid, and then placed in a pre-cooled acylation mixture for esterification, thereby preparing complete cellulose acylate (2- , 3- and 6-positions of the acyl total substitution degree is close to 3.00). The acylation mixture generally contains a carboxylic acid as a solvent, a carboxylic anhydride as an esterification agent, and sulfuric acid as a catalyst. Typically, the amount of carboxylic anhydride used in the process is in stoichiometric excess relative to the total amount of water present in the...

Embodiment 101-118

[0229] [Example 101-118, Comparative Example 101-103]

[0230] (preparation of polymer solution)

[0231] 1) Cellulose acylate:

[0232] In each of Examples and Comparative Examples, cellulose acylate A to F described later was used according to Table 1. Each cellulose acylate was heated and dried at 120°C so that the water content was 0.5% by mass or less. After that, 15 parts by mass of cellulose acylate was used.

[0233] Cellulose acylate A:

[0234] Cellulose acetate powder from pulp with a degree of substitution of 2.91 was used. The viscosity-average degree of polymerization of cellulose acylate A was 270, and the degree of substitution of 6-acetyl group thereof was 0.93. The average diameter of the powder particles is 1.5 mm with a standard deviation of 0.5 mm.

[0235] Cellulose acylate B:

[0236] Cellulose acetate powder from pulp with a degree of substitution of 2.94 was used. The viscosity-average degree of polymerization of cellulose acylate B was 300, an...

Embodiment 151

[0299] (re-stretching of film)

[0300] The stretching was carried out by holding both ends of the cellulose acylate film in Example 113 with tenter clips to stretch the film in a direction perpendicular to the conveying direction in the heating zone. The temperature in the heating zone was 160°C and the draw ratio was 25%. The stretching ratio of the film was obtained according to the following formula in such a manner that the gauge lines of the film were set at constant intervals in a direction parallel to the conveying direction of the film, and the interval was measured before and after stretching.

[0301] Stretch ratio of the film (%) = 100 × {(the distance between the ruler and gauge lines after stretching)-(the distance between the ruler and gauge lines before stretching)} / the distance between the ruler and gauge lines before stretching

[0302] Re and Rth values ​​of the obtained thin film were measured, whereby Re = 160 nm and Rth = -2 nm were obtained. The slow p...

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