| 摘要 |
PURPOSE:The titled composition that is obtained by adding a phosphaphenanthlene to a specific methacrylate copolymer, thus showing remarkably improved thermal stability and having effect to inhibiting discoloration on forming with heat. CONSTITUTION:(A) 100pts.wt. of a methacrylate copolymer consisting of 35- 90wt% of methyl methacrylate, 5-35wt% of styrene and 5-30wt% of maleic anhydride and having a melt-flow index of 0.1-15g/10min. are combined with (B) 0.01-2, preferably 0.05-1pt.wt. of a phosphanaphthalene of the formula (R1 is H, OH, 1-4C alkyl, 1-4C alkoxy; R2, R3 are H, l-8C alkyl, 1-8C alkoxy) and (C) 0.01-1, preferably 0.05-0.5pt.wt. of at least one selected from hindered phenolic compounds, thiodipropionic acids and phosphite esters.
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