Patent ID: 7592390

Claim:
A block copolymer composition comprising: (a) 100 parts by weight of a solid selectively hydrogenated block copolymer having the general configuration A-B, A-B-A, A-B-A-B, (A-B) n , (A-B-A) n , (A-B-A) n X, (A-B) n X or mixtures thereof, where n is an integer from 2 to about 30, and X is coupling agent residue and wherein: i. prior to hydrogenation each A block is a mono alkenyl arene polymer block and each B block is a conjugated diene block having a vinyl content (V 1 ) between 25 weight percent and 85 weight percent; ii. subsequent to hydrogenation about 0-10% of the arene double bonds have been reduced, and at least about 90% of the conjugated diene double bonds have been reduced; iii. each A block having a number average molecular weight between about 3,000 and about 60,000 and each B block having a number average molecular weight (MW 1 ) between about 30,000 and about 300,000; and iv. the total amount of mono alkenyl arene in the hydrogenated block copolymer is about 20 percent weight to about 80 percent weight; and (b) 5 to 250 parts by weight of a hydrogenated tailored softening modifier which is structurally related to the character of the B block of said selectively hydrogenated block copolymer wherein: i. said softening modifier contains at least one hydrogenated conjugated diene wherein prior to hydrogenation said modifier has a vinyl content V 2 , such that the ratio of V 2 /V 1 is between 0.8 and 1.2; ii. subsequent to hydrogenation at least about 90% of the conjugated diene double bonds have been reduced; iii. the ratio (MW 2 )/(MW 1 ) of the number average molecular weight of said softening modifier (MW 2 ) to the number average molecular weight of said B block (MW 1 ) is 0.01 to 0.3, with a minimum molecular weight (MW 2 ) of 2,000 and a maximum molecular weight (MW 2 ) of 20,000; and iv. when the polydispersity index (PDI) of said softening modifier is between 1.0 and less than 1.5, the number average molecular weight of said softening modifier is between 2,000 and 7,000, and when the PDI is between 1.5 and 4.0, the number average molecular weight is between 2,000 and 20,000, where the polydispersity index is the ratio of the weight average molecular weight divided by the number average molecular weight; and (c) wherein said tailored softening modifier is formed in solution in the presence of a solvent in a second reactor to form a second solution and combined with a first solution prepared in a first reactor having a solvent to form a common solution, wherein said hydrogenated block copolymer is polymerized in said first solution or said common solution, and (d) the solvent is removed from the common solution subsequent polymerization of the hydrogenated block copolymer, providing an intimate mixture of said selectively hydrogenated block copolymer and said tailored softening modifier.