PRESSURE-SENSITIVE ADHESIVE COMPOSITION FOR OPTICAL FILMS AND PRESSURE-SENSITIVE ADHESION TYPE OPTICAL FILM
First Claim
1. A pressure-sensitive adhesive composition comprising:
- (I) an acrylic diblock copolymer of formula (1);
A-B
(1),wherein;
A is a methacrylic acid alkyl ester polymer block; and
B is an acrylic acid alkyl ester polymer block,wherein the content of the polymer block B is 10 to 55% by mass, based on a total mass of the acrylic diblock copolymer (I), andwherein the acrylic diblock copolymer (I) has a weight-average molecular weight (Mw) in a range from 9,000 to 300,000, and a molecular weight distribution (Mw/Mn) in a range from 1.0 to 1.5; and
(II) an acrylic triblock copolymer of formula (2);
C1-D-C2
(2),wherein;
C1 and C2 are each independently a methacrylic acid alkyl ester polymer block having a glass transition temperature of not lower than 100°
C.; and
D is an acrylic acid alkyl ester polymer block having a glass transition temperature of not higher than −
20°
C.,wherein the content of the polymer block D is 82 to 95% by mass, based on a total mass of the acrylic triblock copolymer (II), andwherein the acrylic triblock copolymer (I) has a weight-average molecular weight (Mw) in a range from 50,000 to 300,000, and a molecular weight distribution (Mw/Mn) in a range from 1.0 to 1.5,wherein a mass ratio of the acrylic diblock copolymer (I) to the acrylic triblock copolymer (II), (I)/(II), is in the range of 70/30 to 20/80.
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Accused Products
Abstract
There is provided a pressure-sensitive adhesive composition for optical films, which is excellent in heat resistance, weathering resistance and bleed resistance, which has an excellent balance of pressure-sensitive adhesion properties, such as adhesive strength, cohesive force and tack, the tack of which can be controlled, which is excellent in initial reworkability when it is used for applying an optical film to an adherend or applying a protective film to an optical film, and which further exhibits excellent adhesive durability by virtue of rise of adhesive strength when such a film as above in the applied state is kept over a long period of time after application or especially when the film in the applied state is exposed to high temperatures or moist heat. A pressure-sensitive adhesive composition containing a specific acrylic diblock copolymer (I) and a specific acrylic triblock copolymer (II) in a specific proportion and a pressure-sensitive adhesive for optical films using the pressure-sensitive adhesive composition as a base are produced.
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Citations
20 Claims
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1. A pressure-sensitive adhesive composition comprising:
-
(I) an acrylic diblock copolymer of formula (1);
A-B
(1),wherein; A is a methacrylic acid alkyl ester polymer block; and B is an acrylic acid alkyl ester polymer block, wherein the content of the polymer block B is 10 to 55% by mass, based on a total mass of the acrylic diblock copolymer (I), and wherein the acrylic diblock copolymer (I) has a weight-average molecular weight (Mw) in a range from 9,000 to 300,000, and a molecular weight distribution (Mw/Mn) in a range from 1.0 to 1.5; and (II) an acrylic triblock copolymer of formula (2);
C1-D-C2
(2),wherein; C1 and C2 are each independently a methacrylic acid alkyl ester polymer block having a glass transition temperature of not lower than 100°
C.; andD is an acrylic acid alkyl ester polymer block having a glass transition temperature of not higher than −
20°
C.,wherein the content of the polymer block D is 82 to 95% by mass, based on a total mass of the acrylic triblock copolymer (II), and wherein the acrylic triblock copolymer (I) has a weight-average molecular weight (Mw) in a range from 50,000 to 300,000, and a molecular weight distribution (Mw/Mn) in a range from 1.0 to 1.5, wherein a mass ratio of the acrylic diblock copolymer (I) to the acrylic triblock copolymer (II), (I)/(II), is in the range of 70/30 to 20/80. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20)
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Specification