The improver is mainly applied in improving and increasing lube oil viscosity indexes. Features:1) The improver is mainly applied in improving and increasing lube oil viscosity: a) T-612 is applied in making the low grade lube oil thickened in the single stage of low grade lube production; the shearing stability is lower than other brands of improvers b) T-613 is suitable for making the moderate and low grade lube oils thickened, e.g. to improve the viscosity indexes of lube oils for CC.SD grade internal combustion engines; its shearing stability is better than T-612 c) T-614, T-615 are applied in improving the viscosity index of moderate and high grade lube oils and making them thickened with an excellent shearing stability, chiefly preparing the lube oils of high grade multi-stage internal combustion engines2) Performance of OCP viscosity index improver: a) Thickening ability: the thickening ability of the improver varies with the brands. T-612 has a better thickening ability than other brands b) Shearing stability: the performance of shearing stability varies with the volume of molecular weight and its distribution. T-614 is better than T-612, T-613 c) Heat oxidation stability: the improver shows a reliable heat oxidation stability with heat-resistance under high temperature conditions, but without decomposition d) Low temperature performance: T-614 shows a fair performance under low temperature. There is little influence to the pumping performance of multi-grade lube oils by the single application of T-614, which is better than other brands of additives e) The improver shows a good compatibility with other additives without affecting other index

OCP Viscosity Index Improver