| 摘要 |
PROBLEM TO BE SOLVED: To provide an operating fluid usable under a severe condition of a high temperature and a high pressure. SOLUTION: An acrylic ester polymer having improved characteristics and an oil-based composition including an acrylic ester polymer is provided. The acrylic ester polymer comprises a copolymer derived from a first acrylic ester monomer having about one to about four carbon atoms, a second acrylic ester monomer having about 12 to about 14 carbon atoms and a third acrylic ester monomer having about 16 to about 20 carbon atoms. The copolymer has a weight average molecular weight within a range from about 20,000 to about 100,000 dalton, and contains unreacted monomers of about one weight percent or less. COPYRIGHT: (C)2007,JPO&INPIT |
