| 摘要 |
Mixed esters are of formula (I): In the formula, m1 and m3 = 0-7; m2 = 1-7; n = 1 or 2. R is a 1-12C alkyl, cycloalkyl, or alkylcycloalkyl radical, as is >=1 Z1 or Z2 gp. At least one Z1 or Z2 gp. is 2-12C bivalent alkylene, cycloalkylene or alkenylenecycloalkylene radical. Bivalent gps. are attached to an OH radical and a second ester gp. of organo-stannic mercapto-dicarboxylic acid. Mercapto-dicarboxylic acid is reacted with an organostannic halide or oxide at 25-150 degrees C for 20 mins. to 3 hrs., and transesterification is then carried out with a glycol at 70-200 degrees C. The liberated monoalcohol is removed by vacuum distillation. (I) are good PVC stabilisers, have little or no odour and prevent an early yellowing in PVC resins at high temp. They do not crystallise or ppte. in liq. stabilising compositions of PVC resins. |
