Gunze Co., Ltd.

Other

Poratechno Co., Ltd.

Takeshi Yamamoto

Koichi Watanabe

Yoshinori Ishii

Takao Uesugi

A polarizing plate with which, not only suppression in a drop in polarization efficiency, but also with which hue shift and light leakage do not substantially occur, under a high humidity/high temperature environment is provided. The polarizing plate of the present invention includes a polyvinyl-alcohol-based polarizing film, a protective film mainly composed of a cyclic-olefin-based resin and laminated on at least one side of the polarizing film, and an anchor coat agent film and an adhesive layer interposed between the polarizing film and the protective film. The amount of change in optical in-plane retardation of the protective film is 5 nm or less, after 24 hours in an atmosphere of 80&#xb0; C., and the wetting tension of the laminated surface is 500 &#x3bc;N/cm (23&#xb0; C.) or more. The anchor coat agent is made of polyester polyol and polyisocyanate, and the adhesive layer is made of polyvinyl-alcohol-based adhesive.

Polarizing plate

A polarizing plate with which a drop in polarization efficiency, hue shift, and light leakage do not substantially arise, under a high humidity/high temperature environment is provided. The polarizing plate of the present invention comprises a polyvinyl-alcohol-based polarizing film, a protective film having thereon two anchor coat agent layers, mainly composed of a cyclic-olefin-based resin, laminated on at least one side of the polarizing film, with an adhesive. The amount of change in optical in-plane retardation of the protective film is 5 nm or less after 24 hours in an atmosphere of 80&deg; C., and the wetting tension of the anchor coated surface of the protective film is 500 &mgr;N/cm (23&deg; C.) or more. The anchor coat agent layers include a first layer made of polyisocyanate and polyester polyol and/or polyether polyol, and a second layer made of polyvinyl alcohol. The adhesive is made of polyvinyl alcohol.

To provide a laminate film having better shaping processability than conventional laminate films by disposing between the first resin layer and the adhesive layer the second resin layer which has a Vicat softening point lower than that of the first resin layer, has a melting point lower than that of the first resin layer by 2&deg; C. or more, is at least 0.5 times thicker than the first resin layer, and contains as the main component a propylene-&agr;-olefin copolymer. In addition, it becomes possible to provide the laminated structure having the laminate film provided with the second resin layer on the substrate . Hence, the present invention has great industrial significance.

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Moriyama, Japan

Takeshi Yamamoto