Pressure-sensitive adhesive/adhesive and block copolymer suitable for use therein
AssigneeKuraray Co., Ltd.
InventorsYoshihiro Morishita, Hiromichi Nakata, Kenichi Hamada, Kazushige Ishiura
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Abstract
The present invention provides an adhesive composition containing a block copolymer, wherein the block copolymer has a polymer block (A) which is principally composed of a α-methyl styrene unit, and a polymer block (B) which is principally composed of a conjugated diene unit and of which at least part of carbon-carbon unsaturated double bonds may be hydrogenated, and having a good holding power at high temperatures.
Claims10
An adhesive composition containing a block copolymer, characterized in that the block copolymer has a polymer block (A) which is principally composed of an α-methyl styrene unit, and a polymer block (B) which is principally composed of a conjugated diene unit and of which at least part of the carbon-carbon unsaturated double bonds may be hydrogenated, wherein said block copolymer includes:
- (1) a polymer block (A) which has a number-average molecular weight of 1,000 to 300,000;
- and
- (2) a polymer block (B) including:
- a polymer block (b1) which has a number-average molecular weight of 500 to 10,000 and of which 1,4-bond content is less than 30%;
- and a polymer block (b2) which has a number-average molecular weight of 10,000 to 400,000 and of which 1,4-bond content is not less than 30%, and in that the block copolymer has at least one (A-b1-b2) structure.
An adhesive composition containing a block copolymer, characterized in that the block copolymer includes at least one (A-b1-b2) structure obtained by:
- (1) forming a polymer block (A) by polymerizing α-methyl styrene of a 5 to 50% by weight concentration at a temperature from −30° C. to 30° C. in the presence of a polar compound of 0.1 to 10% by weight concentration using a organic lithium compound as an initiator in a nonpolar solvent;
- then
- (2) forming a polymer block (b1) by polymerizing 1 to 100 mol equivalent of conjugated diene with respect to living poly-α-methyl styryl lithium;
- and thereafter
- (3) forming a polymer block (b2) by polymerizing remaining conjugated dienes at a temperature higher than 30° C.
A block copolymer, having a polymer block (A) which is principally composed of a α-methyl styrene unit, and a polymer block (B) which is principally composed of a conjugated diene unit and of which at least part of the carbon-carbon unsaturated double bonds may be hydrogenated, wherein said block copolymer includes:
- (1) a polymer block (A) having a number-average molecular weight of 1,000 to 300,000;
- and
- (2) a polymer block (B) containing a polymer block (b1) having a number-average molecular weight of 500 to 10,000 and a 1,4-bond content of less than 30%, and a polymer block (b2) having a number-average molecular weight of 10,000 to 400,000 and a 1,4-bond content of not less than 30%, and said block copolymer includes at least one (A-b1-b2) structure.
Dependencies are inferred from the claim text.