Method for producing an optical compensating resin film for a polarizing plate

Patent metadata

Field	Value
Publication number	US-9505187-B2
Application number	US-201314095069-A
Country	US
Kind code	B2
Filing date	Dec 3, 2013
Priority date	Apr 26, 2006
Publication date	Nov 29, 2016
Grant date	Nov 29, 2016

Abstract

A method of producing an optical compensating resin film for a polarizing plate including casting a resin exhibiting a glass transition temperature of 150 to 200° C. determined via DSC via a solution casting to form a film; peeling the formed film; conveying the film at a temperature of 60° C. or less for at least 90 seconds; and stretching the film.

First claim

What is claimed is:

1. A method of producing an optical compensating resin film for a polarizing plate comprising the steps in the sequence set forth as follows:
casting a resin exhibiting a glass transition temperature of 150 to 200° C. determined via DSC via a solution casting to form a film;
peeling the formed film;
conveying the film at a temperature of 55° C. or less for at least 90 seconds; and
stretching the film,
wherein the optical compensating resin film satisfies the following requirements:
Ro, defined by the formula Ro=(nx−ny)×d, is 20 to 300 nm at 23° C. and 55% relative humidity,
Rt, defined by the formula Rt=((nx+ny)/2−nz)×d, is 70 to 400 nm at 23° C. and 55% relative humidity; and
a crystallinity degree of said resin film is 0.15 or less:
wherein nx, ny, and nz each respectively represents the refractive index in the major axis x, y, and z direction of a refractive index ellipsoid, nx and ny each represents the refractive index in the in-plane direction of said resin film, nz represents the refractive index in the thickness direction, and d represents the film thickness in nm.

2. The method of producing an optical compensating resin film for a polarizing plate of claim 1 ,
wherein the resin used for the casting step exhibits a glass transition temperature of 170 to 185° C. determined via DSC; and
the film is kept at a temperature of 50° C. or less for at least 90 seconds in the conveying step of the film.

3. The method of producing an optical compensating resin film for a polarizing plate of claim 1 ,
wherein the resin employed in the optical compensating resin film is a cellulose ester.

4. The method of producing an optical compensating resin film for a polarizing plate of claim 3 ,
wherein the cellulose ester has an acyl group having 2 to 4 carbon atoms and simultaneously satisfies the following Formulas (I) and (II):
2.1 ≦X+Y≦ 2.6  (I)

1.0≦X≦2.6  (II)

wherein X represents the substitution degree of an acetyl group, and Y represents the substitution degree of a propionyl group or a butyryl group.

5. The method of producing an optical compensating resin film for a polarizing plate of claim 4 ,
wherein said cellulose ester is cellulose acetatee propionate.

6. The method of producing an optical compensating resin film for a polarizing plate of claim 5 ,
wherein the aforesaid cellulose acetate propionate satisfies the following Formulas (III) and (IV):
1.0≦X≦2.0  (III)

0.5≦Y≦1.3  (IV).

7. The method of producing an optical compensating resin film for a polarizing plate of claim 3 ,
wherein the cellulose ester incorporates a plasticizer having an aromatic terminal ester group and is represented by the following Formula (1):
B-(G-A)n-G-B  Formula (1)

wherein B represents a benzene monocarboxylic acid residual group; G represents an alkylene glycol residual group having 2 to 12 carbon atoms, an aryl glycol residual group having 6 to 12 carbon atoms, or an oxyalkylene glycol residual group having 4 to 12 carbon atoms, A represents an alkylene dicarboxylic acid residual group having 4 to 12 carbon atoms or an aryl dicarboxylic acid residual group having 6 to 12 carbon atoms, and n represents an integer of 1 or more.

8. The method of producing an optical compensating resin film for a polarizing plate of claim 4 ,
wherein the cellulose ester incorporates a plasticizer having an aromatic terminal ester group and is represented by the following Formula (1):
B-(G-A)n-G-B  Formula (1)

wherein B represents a benzene monocarboxylic acid residual group; G represents an alkylene glycol residual group having 2 to 12 carbon atoms, an aryl glycol residual group having 6 to 12 carbon atoms, or an oxyalkylene glycol residual group having 4 to 12 carbon atoms, A represents an alkylene dicarboxylic acid residual group having 4 to 12 carbon atoms or an aryl dicarboxylic acid residual group having 6 to 12 carbon atoms, and n represents an integer of 1 or more.

9. The method of producing an optical compensating resin film for a polarizing plate of claim 5 ,
wherein the cellulose ester incorporates a plasticizer having an aromatic terminal ester group and is represented by the following Formula (1):
B-(G-A)n-G-B  Formula (1)

wherein B represents a benzene monocarboxylic acid residual group; G represents an alkylene glycol residual group having 2 to 12 carbon atoms, an aryl glycol residual group having 6 to 12 carbon atoms, or an oxyalkylene glycol residual group having 4 to 12 carbon atoms, A represents an alkylene dicarboxylic acid residual group having 4 to 12 carbon atoms or an aryl dicarboxylic acid residual group having 6 to 12 carbon atoms, and n represents an integer of 1 or more.

10. The method of producing an optical compensating resin film for a polarizing plate of claim 6 ,
wherein the cellulose ester incorporates a plasticizer having an aromatic terminal ester group and is represented by the following Formula (1):
B-(G-A)n-G-B Formula (1)

wherein B represents a benzene monocarboxylic acid residual group; G represents an alkylene glycol residual group having 2 to 12 carbon atoms, an aryl glycol residual group having 6 to 12 carbon atoms, or an oxyalkylene glycol residual group having 4 to 12 carbon atoms, A represents an alkylene dicarboxylic acid residual group having 4 to 12 carbon atoms or an aryl dicarboxylic acid residual group having 6 to 12 carbon atoms, and n represents an integer of 1 or more.

11. The method of producing an optical compensating resin film for a polarizing plate of claim 2 ,
wherein the resin employed in the optical compensating resin film is a cellulose ester.

12. The method of producing an optical compensating resin film for a polarizing plate of claim 11 ,
wherein the cellulose ester has an acyl group having 2 to 4 carbon atoms and simultaneously satisfies the following Formulas (I) and (II):
2.1 ≦X+Y≦ 2.6  (I)

1.0≦X≦2.6  (II)

wherein X represents a substitution degree of an acetyl group, and Y represents a substitution degree of a propionyl group or a butyryl group.

13. The method of producing an optical compensating resin film for a polarizing plate of claim 12 ,
wherein said cellulose ester is cellulose acetate propionate.

14. The method of producing an optical compensating resin film for a polarizing plate of claim 13 ,
wherein said cellulose acetate propionate satisfies the following Formulas (Ill) and (IV):
1.0≦X≦2.0  (III)

0.5≦Y≦1.3  (IV).

15. The method of producing an optical compensating resin film for a polarizing plate of claim 11 ,
wherein the cellulose ester incorporates a plasticizer having an aromatic terminal ester group and is represented by the following Formula (1):
B-(G-A)n-G-B  Formula (1)

wherein B represents a benzene monocarboxylic acid residual group; G represents an alkylene glycol residual group having 2 to 12 carbon atoms, an aryl glycol residual group having 6 to 12 carbon atoms, or an oxyalkylene glycol residual group having 4 to 12 carbon atoms, A represents an alkylene dicarboxylic acid residual group having 4 to 12 carbon atoms or an aryl dicarboxylic acid residual group having 6 to 12 carbon atoms, and n represents an integer of 1 or more.

16. The method of producing an optical compensating resin film for a polarizing plate of claim 12 ,
wherein the cellulose ester incorporates a plasticizer having an aromatic terminal ester group and is represented by the following Formula (1):
B-(G-A)n-G-B  Formula (1)

wherein B represents a benzene monocarboxylic acid residual group; G represents an alkylene glycol residua

Assignees

• Konica Minolta Inc

Inventors

• Takagi Takahiro

Classifications

• C08K5/103

  with polyalcohols · CPC title

• B29C55/085

  in several stretching steps · CPC title

• G02B5/3083

  Birefringent or phase retarding elements (G02B5/3008, G02B5/3016 take precedence; systems for polarisation control G02B27/286; manufacturing phase modulating patterns by lithographic processes G03F7/001) · CPC title

• B29C55/143

  firstly parallel to the direction of feed and then transversely thereto · CPC title

• G02B5/3033

  in the form of a thin sheet or foil, e.g. Polaroid · CPC title