Method for producing resin film, casting die, device for producing resin film, resin film, polarizing plate, and liquid crystal display device

Patent metadata

Field	Value
Publication number	US-9492977-B2
Application number	US-201113881079-A
Country	US
Kind code	B2
Filing date	Sep 8, 2011
Priority date	Oct 26, 2010
Publication date	Nov 15, 2016
Grant date	Nov 15, 2016

Abstract

An aspect of the present invention is a method for producing a resin film, wherein in a casting step of a solution cast film-forming method, a dope is discharged from a discharge port of the casting die to cast the dope onto the support while a solvent capable of dissolving a transparent resin is flowed from the positions above the discharge port of the casting die through the outer surface of the casting die, and further from the longitudinally opposite ends of the discharge port of the casting die. The casting die has a surface energy of a first region which is 10 mN/m to 30 mN/m higher than a surface energy of a second region, the first region being the region, on the outer surface of the casting die, surrounded by the positions above the longitudinally opposite ends of the discharge port of the casting die and the longitudinally opposite ends of the discharge port of the casting die, and the second region being a region which is closer to a longitudinally central portion of the discharge port of the casting die than the first region.

First claim

The invention claimed is:

1. A method for producing a resin film, comprising:
a casting step of casting a resin solution containing a transparent resin from a casting die onto a running support to form a cast membrane; and
a releasing step of releasing the cast membrane from the support,
wherein, in the casting step, the resin solution is discharged from a discharge port of the casting die to cast the resin solution onto the support while a solvent capable of dissolving the transparent resin is flowed on an outer surface of the casting die from the positions above longitudinally opposite ends of the discharge port of the casting die toward the longitudinally opposite ends of the discharge port of the casting die, so that the solvent falls from the longitudinally opposite ends of the discharge port of the casting die, and
the casting die has a surface energy of a first region which is 10 mN/m to 30 mN/m higher than a surface energy of a second region, the first region being the regions, on the outer surface of the casting die, surrounded by the positions above the longitudinally opposite ends of the discharge port of the casting die and the longitudinally opposite ends of the discharge port of the casting die, and the second region being a region on the outer surface of the casting die which is closer to a longitudinally central portion of the discharge port of the casting die than the first region.

2. The method for producing a resin film according to claim 1 , wherein the first region has a surface roughness as ten-point height of irregularities Rz of 1,000 nm to 8,000 nm.

3. The method for producing a resin film according to claim 1 , wherein each of the regions of the first region has a length in a direction parallel to the longitudinal direction of the discharge port of 1 mm to 10 mm.

4. The method for producing a resin film according to claim 1 , wherein each of the regions of the first region has a length in a direction parallel to the longitudinal direction of the discharge port of 3 mm to 10 mm.

5. The method for producing a resin film according to claim 1 , wherein the transparent resin is a cellulose ester resin, and the solvent contains methylene chloride.

Assignees

• Mizoguchi Keisuke
• Konica Minolta Inc

Inventors

• Mizoguchi Keisuke

Classifications

• 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

• B29K2001/00

  Use of cellulose, modified cellulose or cellulose derivatives, e.g. viscose, as moulding material · CPC title

• B29D7/01 Primary

  Films or sheets · CPC title

• B29C41/28 Primary

  by depositing flowable material on an endless belt · CPC title