PURPOSE: To provide the titled stabilizer composed of a specific basic lead maleate sulfate, and having remarkably improved thermal stability and improved insulation property.
CONSTITUTION: The objective stabilizer is composed of a basic lead maleate sulfate of formula nPbO.PbMx(SO4)y.mH2O (n is 1.5W3.3; M is maleic acid residue; x is 0.05W0.7; y is 0.95W0.3; x+y=1; m is ≤1) and having an X-ray diffraction pattern satisfying the formulas 5≥I12.1/I10.0≥0.1 and 2≥I9.02/I12.1≥0 (I12.1, I10.0 and I9.02 are relative intensities of the X-ray diffraction pattern corresponding to the spacings of 12.1, 10.0 and 9.02, respectively). The compound can be produced by reacting maleic acid (anhydride) with an aqueous slurry containing lead monoxide and a catalytic amount of a monobasic acid or its ammonium salt, and reacting the reaction product with sulfuric acid keeping the molar ratio of [maleic acid (anhydride)]:(sulfuric acid) to 1:19W7:3, and that of (lead monoxide):(sum of the acids) to (2.5W4.3):1.
SATOU TOSHIO
SATOU KIICHI
MARUTANI KEIICHI
