| 摘要 |
PURPOSE:To obtain a viscosity index improver excellent in the ability to improve viscosity index, low-temperature viscosity characteristics, fuel-saving properties, oxidation resistance and an effect of reducing friction and abrasion by using a polymer comprising a specified alkyl (meth)acrylate monomer. CONSTITUTION:This improver comprises a polymer comprising at least 70wt.% alkyl (meth)acrylate with 10C or lower alkyl. The above alkyl (meth)acrylate used is desirably an alkyl acrylate with 1-4C alkyl, an alkyl (meth)acrylate with 5-10C alkyl or a combination thereof with alkyl (meth)acrylate with 1-4C alkyl. It is more desirably a mixture of alkyl acrylates with 1-4C alkyl and with 8C alkyl more particulary such a mixture in a 1-4C alkyl acrylate/8C alkyl acrylate weight ratio of 0:100 to 30:70. |
