ADDITIVE FOR PREVENTING OIL FROM DIFFUSING

摘要

PURPOSE: To obtain an oil-diffusion preventing agent, comprising a specific fluorine-based copolymer and capable of preventing a base oil in a grease from diffusing from a coated surface by adding thereof to the grease and maintaining properties essential to the grease such as heat resistance or low-temperature stability. CONSTITUTION: This additive for preventing oil from diffusing a fluorine-based copolymer having perfluoroalkyl groups and polyoxypropylene units (preferably having 1000-3000 weight-average molecular weight). The fluorine-based copolymer is preferably obtained by copolymerizing (A) an ethylene monomer containing the perfluoroalkyl group such as a monomer of formula I (R1 is the 1-30C perfluoroalkyl; R is H or CH3 ; R' is a 1-10C alkylene; R" is H or a 1-10C alkyl) with (B) an ethylenically unsaturated monomer containing the polyoxypropylene units such as a monomer of formula II [(m) is 1-25]. Furthermore, a monomer having a 6-12C perfluoroalkyl group is preferred as the component (A) and a monomer having 3-7 polyoxypropylene units is preferred as the component (B).