Rohm and Haas Company

Bernard George Kinker

Robert H Gore

Bridget Marie Stevens

Charles William Hyndman

Joseph M Bollinger

Jerry William Washel

David Arthur Pierce

A process for the preparation of continuously variable-composition copolymers by effecting gradual changes in monomer composition during the polymerization is disclosed. Poly(meth)acrylate copolymers made by the process of the present invention have improved lubricating oil additive properties, for example, as pour point depressants, when compared to related polymer additives made by conventional means.

Process for preparing continuously variable-composition copolymers

Polymer compositions derived from selected alkyl (meth)acrylate ester monomers used in certain weight ratios to provide improved viscosity control and low temperature performance characteristics in phosphate ester aircraft hydraulic fluids is disclosed. Polymer compositions for use as viscosity index improving additives in aircraft hydraulic fluids contain from 40 to 100 weight percent (C.sub.1 -C.sub.10)alkyl (meth)acrylate and zero to 60 weight percent (C.sub.11 -C.sub.20)alkyl (meth)acrylate monomer units. Preferred polymer compositions based on 40 to 70 weight percent (C.sub.1 -C.sub.10)alkyl (meth)acrylate and 30 to 60 weight percent (C.sub.11 -C.sub.15)alkyl (meth)acrylate monomer units combine good solubility in the phosphate ester hydraulic fluids with good viscosity control at low and high temperatures.

Viscosity index improving additives for phosphate ester-containing

A lubricating oil composition includes from 0.01 weight per cent to 2 weight per cent of a polymer that includes repeating units derived from a (C.sub.8 -C.sub.15)alkyl (meth)acrylate monomer and 98 weight per cent to 99.99 weight per cent of a vegetable oil or a polyol ester.

Growing community of inventors

Kintnersville, PA, United States of America

Bernard George Kinker