| 摘要 |
The discoloration on hot compounding of compositions comprising a vinyl chloride resin and iron-containing asbestos is avoided or removed by incorporating 0.25 to 20% by weight of the resin of an organic compound having in the molecule the group <FORM:0994708/C3/1> The resin may be polyvinyl chloride, a copolymer of vinyl chloride with vinyl acetate, vinylidene chloride or ethylene, or mixtures thereof with other resins, e.g. polyolefins and chlorinated polyethylene. Many suitable organic compounds are listed including dicyandiamide, melamine, substituted guanidines, guanazole, ammelide, triazines and substituted triazines, guanamine and substituted guanamines, ammeline, 2-amino pyrimidine and substituted pyrimidines, and 2-amino imidazole and substituted imidazoles. The compositions may also comprise pigments and fillers, e.g. calcium carbonate, silica, clays and titanium dioxide, and plasticizers, e.g. dioctyl phthalate, dibutyl sebacate, dioctyl sebacate, tricresyl phosphate, epoxidized soya bean oil and epoxidized esters of oleic, linoleic and ricinoleic acids; and may be formed into floor tiles. Examples describe compositions comprising a vinyl chloride/vinyl acetate copolymer, dioctyl phthalate, epoxidized soya bean oil, titanium dioxide, calcium carbonate and asbestos together with (1 to 9 and 12) dicyandiamide, (10 and 13) melamine, (11) dicyandiamide and melamine, (14 and 15) guanidine carbonate, (16) dicyandiamide and guanidine carbonate, (17 to 19 and 22) stearoguanamine, (20) acetoguanamine and (21) benzoguanamine; and compositions comprising polyvinyl chloride, dioctyl phthalate, epoxidized soya bean oil, titanium dioxide, calcium carbonate and asbestos together with (23 and 26) dicyandiamide, (24 and 27) melamine and (25) dicyandiamide and melamine. |
