US 2011/0033640 A1Published application

Process for producing optical film, optical film, polarizer, and liquid crystal display

AssigneeKonica Minolta Opto, Inc.

InventorsRumiko Yamada, Atsuko Matsuda

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Abstract

Provided is a method for producing an optical film which suffers neither flatness deterioration nor film breakage and is free from problems concerning undulating undulation and partial light leakage. The process for optical film production comprises laminating a cellulose ester resin layer (A) to an acrylic resin layer (B) by coextrusion. The process is characterized in that the cellulose ester resin layer (A) contains 55 to 99 mass % cellulose ester resin and the acrylic resin layer (B) contains 55 to 99 mass % acrylic resin, that the web is conveyed while keeping the layer (A) and the layer (B) in contact with the surface of a first cooling roll and the surface of a second cooling roll, respectively, and that when the surface temperature of the first cooling roll and the surface temperature of the second cooling roll are expressed by Ta (° C.) and Tb (° C.), respectively, then the Ta (° C.) and Tb (° C.) satisfy the following relationship (1). (Ta−80)° C.<Tb (° C.)<(Ta−5)° C.

Claims6

Dependent claims

A method for producing an optical film by laminating a cellulose ester resin layer (A) and an acrylic resin layer (B) via coextrusion of a melt composition of a cellulose ester resin and a melt composition of an acrylic resin, wherein

the cellulose ester resin layer (A) contains 55 to 99% by mass of a cellulose ester resin, and 1 to 45% by mass of an acrylic resin, wherein total content of the cellulose ester resin and the acrylic resin is 100% by mass,
the acrylic resin layer (B) contains 55 to 99% by mass of an acrylic resin, and 1 to 45% by mass of a cellulose ester resin, wherein total content of the cellulose ester resin and the acrylic resin is 100% by mass,
coextruded web is conveyed while cooling by a first cooling roll and a second cooling roll arranged subsequent to the first cooling roll, wherein the coextruded web is conveyed while the cellulose ester resin layer (A) being in contact with a surface of the first cooling roll, and the acrylic resin layer (B) being in contact with a surface of the second cooling roll, and
Ta (° C.) and Tb (° C.) satisfy the following relation 1, wherein Ta (° C.) is a surface temperature of the first cooling roll, and Tb (° C.) is a surface temperature of the second cooling roll,
(Ta−80)° C.<Tb (° C.)<(Ta−5)° C. Relation 1

2 more elements

Dependencies are inferred from the claim text.