Block copolymer blends with improved oil absorption resistance
AssigneeShell Oil Company
InventorsGlenn R. Himes, Andrea Sanders
Life of this patent
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Abstract
A thermoplastic blend with the ability to absorb less than 40% of an oil, and having a superior tensile strength comprises about 80 to about 20 phr of an elastomeric block copolymer having the general configuration A-B-A, wherein the B block is a butadiene hydrocarbon block consisting of about 35 to about 55 mole percent of condensed butadiene units in the 1,2 configuration, and about 20 to about 80 phr of a block copolymer having the general configuration A-B-A, wherein the B block is a hydrogenated butadiene hydrocarbon block consisting of about 18 to about 34 mole percent of condensed butadiene units in the 1,2 configuration.
Claims6
A thermoplastic blend, comprising:
- (a) about 80 to about 20 parts by weight of an elastomeric block copolymer having the general configuration A-B-A, wherein:
- (i) each A block is a polymerized monoalkenyl aromatic hydrocarbon block having an average molecular weight of about 4000 to about 115,000;
- (ii) the A blocks, in combination, comprise about 5 to about 35w% of the elastomeric block copolymer;
- and
- (iii) each B block is a non-hydrogenated butadiene hydrocarbon block consisting of 8 to 55 mole percent condensed butadiene units in the 1,2 configuration, or a hydrogenated butadiene hydrocarbon block consisting of 35 to 55 mole percent condensed butadiene units in the 1,2 configuration, and said B block has an average molecular weight of between about 20,000 and about 450,000;
- and
- (b) about 20 to about 80 parts by weight of a block copolymer having the general configuration A-B-A wherein:
- (i) each A block is a polymerized monoalkenyl aromatic hydrocarbon block having an average molecular weight of about 4000 to about 115,000;
- (ii) said A blocks, in combination, comprise about 5 to about 35 w % of the block copolymer;
- (iii) each B block is a polymerized butadiene hydrocarbon block consisting of about 18 to 34 mole percent condensed butadiene units in the 1,2 configuration, and said B block has an average molecular weight of between about 20,000 and about 450,000;
- and
- (iv) the B blocks are hydrogenated to an unsaturation that is less than about 5% of the original unsaturation.
Dependencies are inferred from the claim text.