| 摘要 |
A central system fluid composition composed of 5-30% by weight of a viscosity index improver, up to 10% by weight of another additive, and the balance being a hydrocarbon-type base oil, which is characterized in that the hydrocarbon-type base oil is composed of 50-100% by weight, based on its total weight, of at least one chief base oil component selected from the group consisting of A. polybutenes with an average molecular weight of 100 - 500, B. homo- or copolymers with an average molecular weight of 100 to 500 of at least one alpha -olefin containing 2-12 carbons, excepting butenes, and C. hydrogenation products boiling at 250 DEG -380 DEG C of high aromatic components which are obtained by cracking petroleum oils, AND 0-50% BY WEIGHT, BASED ON ITS TOTAL WEIGHT, OF A MINERAL OIL; AND THAT THE VISCOSITY INDEX IMPROVER IS COMPOSED OF AT LEAST ONE COMPONENT SELECTED FROM THE GROUP CONSISTING OF 1. POLYMETHACRYLATES WITH AN AVERAGE MOLECULAR WEIGHT OF 50,000-200,000, WHICH ARE OBTAINED BY POLYMERIZING AT LEAST ONE ESTER OF A SATURATED, MONOHYDRIC ALIPHATIC ALCOHOL OF 1-18 CARBONS WITH METHACRYLIC ACID, AND 2. POLYMERS WITH AN AVERAGE MOLECULAR WEIGHT OF 10,000-200,000 WHICH ARE OBTAINED BY POLYMERIZING AT LEAST ONE COMPOUND SELECTED FROM THE GROUP CONSISTING OF THE OLEFINS OF 2-5 CARBONS, DIOLEFINS OF 2-5 CARBONS AND AROMATIC VINYL COMPOUNDS.
|
