Adhesive layer-attached retardation film, and elliptical polarizing plate and liquid crystal display device each utilizing same

[0152] (Production Example 1: Production of retardation film)

[0153] A propylene/ethylene random copolymer containing approximately 5% of ethylene units ("Sumitomo Nippon W151" manufactured by Sumitomo Chemical Co., Ltd.) was formed into a film to obtain a roll film composed of a polypropylene resin having a thickness of 40 μm. By uniaxially stretching the roll film in the transverse direction, a uniaxial retardation film is obtained. For this retardation film, the in-plane retardation value R 0 =90nm, the retardation value R in the thickness direction th =45nm, the thickness is 9μm. Then, a self-adhesive surface protection film manufactured by Toray Film Processing Co., Ltd., which is a brand name "Toretec 7332", was bonded to one side of the retardation film made of polypropylene resin.

[0154] [Example 1]

[0155] (a) Preparation of coating liquid for undercoat layer

[0156] A polyester resin (I) with a weight average molecular weight of 35,000 containing structural units derived from neopentyl glycol, ethylene glycol, terephthalic acid, and isophthalic acid was dissolved in toluene: methyl ethyl ketone = 4: In the mixed solvent of 1, a coating liquid for an undercoat layer having a polyester resin (I) concentration of 10% was prepared. The content ratio of the structural unit derived from neopentyl glycol, ethylene glycol, terephthalic acid, and isophthalic acid in the polyester resin (I) is 1:1:1:1 in terms of molar ratio.

[0157] (b) Formation of undercoat layer for retardation film

[0158] On the surface of the retardation film made of polypropylene resin obtained in Production Example 1 on the side opposite to the surface on which the surface protection film was laminated, the cumulative exposure was 15.9 kJ/m 2 Implement corona discharge treatment. Within 5 minutes after the corona discharge treatment, the corona treated surface was coated with the above-mentioned primer coating liquid using a Meyer rod (#5), and then dried in an oven at 80°C for 3 minutes. An undercoat layer with a thickness of 3.1 μm was formed on the retardation film.

[0159] (c) Production of elliptically polarizing plate

[0160] A polarizing plate (SRW062 manufactured by Sumitomo Chemical Co., Ltd.) was prepared with a protective film made of triacetyl cellulose bonded to both sides of a polarizing film in which iodine was oriented on polyvinyl alcohol, and polyurethane was laminated on one side Acrylate-based sheet adhesive (NS300MP purchased from Lintec), and a polarizing plate with an adhesive layer was produced. On the other hand, the surface protective film was peeled off from the undercoated retardation film produced in (b) above, and the cumulative exposure amount was 15.9kJ/m on this surface (polypropylene resin surface) 2 The corona discharge treatment was performed, and within 5 minutes after the corona discharge treatment, the polarizing plate with an adhesive layer produced as described above was bonded using the adhesive layer on the corona treated surface. Then, the cumulative irradiation dose is 15.9kJ/m on the undercoat side 2 Implemented corona discharge treatment. Within 5 minutes after the corona discharge treatment, an acrylic sheet adhesive (P3132 purchased from Lintec) was bonded to the corona-treated surface to produce an elliptically polarizing plate with an adhesive layer. The elliptically polarizing plate with an adhesive layer obtained here has a layer structure of sheet adhesive (P3132)/undercoat layer/polypropylene retardation film/sheet adhesive (NS300MP)/polarizing plate.

[0161] [Example 2]

[0162] A polyester resin (II) with a weight average molecular weight of 33,000 containing constituent units derived from neopentyl glycol, ethylene glycol, terephthalic acid, isophthalic acid, and 5-sodium isophthalate is dissolved in In the mixed solvent of toluene: methyl ethyl ketone = 1:1, the coating solution for the primer layer having a concentration of 10% of the polyester resin (II) thus obtained was used. Other than that, the same as in the examples 1 In the same manner, an elliptically polarizing plate with an adhesive layer was produced. The content of the constituent units derived from neopentyl glycol, ethylene glycol, terephthalic acid, isophthalic acid, and 5-sodium isophthalate in the polyester resin (II) is calculated as a molar ratio 1:1:1:1:1:0.005.