| 摘要 |
The pigments are of the lead chromate-sulphate type, made by common pptn. at temps. up to 100 degrees C and opt. post-treatment in aq. suspension with 5-40 wt.% SiO2 and 2-16% Sb (III), Zn and/or Sn (II) cpds., part of the lead being replaced by barium during mfr. to give a molar ratio of Ba:Pb of 98:2 to 2:98. Post-treatment of the ppted. 4-component system is pref. carried out in at least 3 steps. to give successive protective coatings of SiO2, Sb and/or Sn cpds., SiOi, and opt. Zn cpd., followed again by SiO2. Light and esp. heat-resistance of the yellow pigments are improved. They are suitable for pigmenting thermoplastics, pref. those based on PVC and polyethylene and for use in corrosion-protective coatings on metals.
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