| 摘要 |
PROBLEM TO BE SOLVED: To obtain a flame-retardant methacrylic resin composition keeping original properties of a transparent resin by kneading a methacrylic resin with a specific halogen-containing phosphoric acid ester. SOLUTION: This flame-retardant methacrylic resin composition is obtained by previously mixing each 0.5-10 pts.wt. of halogen-containing phosphoric acid esters (b) and (c) having phosphoric acid ester structures represented by formulas I [R1 and R2 are each a monovalent or divalent hydrocarbon (having a halogen, phosphorus or oxygen atom in the molecule) or H], and II (R3 and R4 have the same meanings as these of the R1 and R2) with 100 pts.wt. of a methacrylic resin (a) by a Henschel mixer or the like, melting and kneading the previously mixed materials, and pelletizing the melted and kneaded product. The obtained resin composition satisfies the relations of the equations B>A and C>A (A is sheet-forming temperature ( deg.C) of the methacrylic resin (a); B and C are each degradation-starting temperatures ( deg.C) of the phosphoric acid esters (b) and (c) respectively.
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