POLYMER COMPOSITIONS HAVING IMPROVED PORPERTIES AS VISCOSITY INDEX IMPROVERS AND USE THEREOF IN LUBRICATING OILS

摘要

The present disclosure is directed to polymer compositions for use as viscosity modifiers comprising at least two ethylene-based copolymer components. The polymer composition comprises (a) a first ethylene-olefin copolymer and (b) a second ethylene-olefin copolymer. The first ethylene-olefin copolymer (a) has an ethylene content from about 60 to about 80 wt% and the second ethylene-olefin copolymer (b) has an ethylene content of less than about 60 wt%. The first ethylene-olefin copolymer(a) has a Melt Flow Rate Ratio (MFRR), defined as the ratio of the MFR measured at 230°C/21.6 kg and at 230°C/2.16 kg, of greater than 30 and optionally also has a Melt Flow Rate (MFR) of at least 10 about 1.5 g/10 min, measured by ASTM D 1238 condition L (230°C/2.16 kg).