Patent ID: 7625851
Filing Date: 2009-12-01
Classification: C10L,C10M,C10N

Abstract:
1. A liquid oil composition comprising: a base oil; and a viscosity index improving amount of about 0.2 to 2.0% by weight of the composition of a hydrogenated block copolymer having at least one polymer block B and optionally at least one polymer block A, 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 has a number average molecular weight between about 3,000 and about 60,000 and each B block has 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 from 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, with the proviso that when no A blocks are present, then each B block comprises terminal regions that are rich in conjugated diene units and one or more non-terminal units that are rich in mono alkenyl arene units, and with the further proviso that when more than one A block is present, then each A block has a molecular weight of less than about 5000; and optionally one or more components selected from an anti-corrosive additive, an antioxidant, a detergent, a pour point depressant or additional VI improvers that are different from said hydrogenated anionic block copolymer.