▎ 摘　　要

NOVELTY - Acralate-sodium sulfate containing acrylate-quaternary ammonium-containing ethylene based temperature-resistant and salt-tolerant copolymer (A) is new. The monomer of (A) comprises acralate compound (I), sodium sulfate containing acrylate compound (II) and quaternary ammonium-containing ethylene compound (III). USE - (A) is useful in oil-displacing polymer for oil displacement in high calcium and magnesium environment (claimed). DETAILED DESCRIPTION - Acralate-sodium sulfate containing acrylate-quaternary ammonium-containing ethylene based temperature-resistant and salt-tolerant copolymer (A) is new. The monomer of (A) comprises acralate compound of formula (I), sodium sulfate containing acrylate compound of formula (II) and quaternary ammonium-containing ethylene compound of formula (III). R1= -OH or -NH2; R2and R3= H or 1-10C alkyl; R4-R6= H or 5-30C alkyl; and X = halo elements. INDEPENDENT CLAIMS are also included for: preparation of (I); and oil-displacing polymer, comprising at least one (A).