Stability improvement of aluminum hydroxide in PVC compound

Abstract

An aluminum hydroxide composition is disclosed, having diminished tendency to cause discoloration on heating at 177° C. of a plastic composition whose major polymeric component is polyvinyl chloride, comprising aluminum hydroxide and an amount, effective in diminishing discoloration, of at least one inorganic perchlorate salt selected from the group consisting of alkali metal perchlorates and alkaline earth metal perchlorates.

What is claimed is:  
     
         1 . An aluminum hydroxide composition having diminished tendency to cause discoloration on heating at 177° C. of a plastic composition whose major polymeric component is polyvinyl chloride, comprising aluminum hydroxide and an amount, effective in diminishing said discoloration, of at least one inorganic perchlorate salt selected from the group consisting of alkali metal perchlorates and alkaline earth metal perchlorates.  
     
     
         2 . The composition of  claim 1 , wherein said effective amount is in the range from 0.03 parts by weight to 3 parts by weight per 100 parts by weight of aluminum hydroxide.  
     
     
         3 . The composition of  claim 1 , wherein said inorganic perchlorate is sodium perchlorate.  
     
     
         4 . The composition of  claim 3 , wherein said perchlorate is sodium perchlorate monohydrate.  
     
     
         5 . A plastic composition having diminished tendency to discolor on heating at 177° C. in the presence of aluminum hydroxide, comprising polyvinyl chloride, aluminum hydroxide, and an amount, effective in diminishing said tendency to discolor, of at least one inorganic perchlorate salt selected from the group consisting of alkali metal perchlorates and alkaline earth metal perchlorates.  
     
     
         6 . The composition of  claim 5 , wherein the amount of aluminum hydroxide is a flame retardant amount.  
     
     
         7 . The composition of  claim 6 , wherein the amount of aluminum hydroxide is in the range from 15 parts by weight to 150 parts by weight per 100 parts by weight of polyvinyl chloride.  
     
     
         8 . The composition of  claim 5 , wherein the amount of said inorganic perchlorate is in the range from 0.03 parts by weight to 3 parts by weight per 100 parts by weight of aluminum hydroxide.  
     
     
         9 . The composition of  claim 5 , wherein said inorganic perchlorate is sodium perchlorate.  
     
     
         10 . The composition of  claim 5 , additionally comprising at least one plasticizer.  
     
     
         11 . The composition of  claim 5 , additionally comprising at least one heat stabilizer.  
     
     
         12 . The composition of  claim 10 , wherein said at least one plasticizer is selected from the group consisting of dialkyl phthalates and trialkyl trimellitates having independently in each alkyl group seven to eleven carbon atoms.  
     
     
         13 . The composition of  claim 1   1 , wherein said at least one heat stabilizer is a barium, calcium, magnesium, strontium, or zinc salt of a non-nitrogenous monocarboxylic acid having 6-24 carbon atoms.  
     
     
         14 . A masterbatch composition adapted for safe storage, transport, and compounding with a plastic composition whose major polymeric component is polyvinyl chloride, comprising aluminum hydroxide and at least one inorganic perchlorate salt selected from the group consisting of alkali metal perchlorates and alkaline earth metal perchlorates, said masterbatch containing from 7 parts by weight to 500 parts by weight of said perchlorate salt per 100 parts by weight of aluminum hydroxide.  
     
     
         15 . The masterbatch composition of  claim 14 , containing from 30 parts by weight to 150 parts by weight of said inorganic perchlorate salt per 100 parts by weight of aluminum hydroxide.  
     
     
         16 . The masterbatch composition of  claim 14 , wherein said inorganic perchlorate is sodium perchlorate.  
     
     
         17 . The masterbatch composition of  claim 16 , wherein said inorganic perchlorate is sodium perchlorate monohydrate.  
     
     
         18 . A method of diminishing the tendency to cause discoloration on heating at 177° C. of an aluminum hydroxide containing plastic composition whose major polymeric component is polyvinyl chloride, comprising the steps of mixing polyvinyl chloride with a masterbatch according to  claim 14 , and adding thereto additional aluminum hydroxide such that the composition contains from 15 parts by weight to 150 parts by weight of aluminum hydroxide per 100 parts by weight of polyvinyl chloride and from 0.03 parts by weight to 3 parts by weight of said inorganic perchlorate salt per 100 parts by weight of aluminum hydroxide.  
     
     
         19 . An insulated electrical conductor comprising a metallic conductor, a first insulating layer comprising flexible polyvinyl chloride surrounding said conductor, and a second layer surrounding said first insulating layer, said second layer comprising the composition of  claim 6   
     
     
         20 . The insulated electrical conductor of  claim 19 , wherein said second layer comprises a second flame retardant.  
     
     
         21 . The insulated electrical conductor of  claim 20 , wherein said second flame retardant is antimony trioxide.  
     
     
         22 . In an aluminum hydroxide containing plastic composition whose major polymeric constituent is polyvinyl chloride, the improvement consisting of inclusion therein of an amount, effective in diminishing discoloration of said composition upon heating at 177° C., of at least one inorganic perchlorate salt selected from the group consisting of alkali metal perchlorates and alkaline earth metal perchlorates.