IMPROVED STABILIZERS FOR HALOGEN-CONTAINING POLYMERS

摘要

Improved stabilizer compositions are provided which impart significant long-term heat stabilization to halogen-containing vinyl polymers such as polyvinyl chloride. The improved stabilizer compositions combine one or more metal-containing primary stabilizer compounds with a finely divided co-stabilizing phosphate material of a predetermined surface area. The phosphate material includes an anhydrous or hydrous sodium or potassium monohydrogen phosphate, lithium dihydrogen phosphate, or alkali-metal pyrophosphate. The novel combination of stabilizers enables a reduction in the amount of metal-containing stabilizer, if desired, while still yielding long-term stability in the resultant polymer, or provides the ability to raise process temperature and reduce cycle times of molding operations.