Gels from controlled distribution block copolymers
AssigneeKraton Polymers U.S. LLC
InventorsDavid J. St. Clair, Dale Lee Handlin JR., Carl L. Willis
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Abstract
The present invention relates to gels prepared from novel anionic block copolymers of mono alkenyl arenes and conjugated dienes, and to blends of such block copolymers with other polymers. The block copolymers are selectively hydrogenated and have mono alkenyl arene end blocks and controlled distribution blocks of mono alkenyl arenes and conjugated dienes. The block copolymer may be combined with tackifying resins, oils and other components to form the gels of the present invention.
Claims10
An oil gel composition comprising 100 parts by weight of at least one hydrogenated block copolymer and about 350 to about 2000 parts by weight of an extending oil, wherein said hydrogenated block copolymer has at least one polymer block A and at least one polymer block B, and wherein:
- a. prior to hydrogenation each A block is a mono alkenyl arene homopolymer block and each B block is a controlled distribution copolymer block of at least one conjugated diene and at least one mono alkenyl arene;
- b. 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;
- c. 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 between about 20,000 and about 300,000;
- d. each B block comprises terminal regions adjacent to the A blocks that are rich in conjugated diene units and one or more regions not adjacent to the A blocks that are rich in mono alkenyl arene units;
- e. the total amount of mono alkenyl arene in the hydrogenated block copolymer is about 20 percent weight to about 80 percent weight;
- and
- f. the weight percent of mono alkenyl arene in each B block is between about 10 percent and about 75 percent.
Dependencies are inferred from the claim text.