Thermoplastic moulding compounds exhibiting improved chemical resistance

A thermoplastic molding composition, comprising a mixture of

• (A) from 30 to 69% by weight, based on the sum of components (A), (B) and (C), of a methyl methacrylate polymer obtainable by polymerizing a mixture consisting of
• (A1) from 90 to 100% by weight, based on (A), of methyl methacrylate, and
• (A2) from 0 to 10% by weight, based on (A), of a C1-C8-alkyl ester of acrylic acid, and
• (B) from 30 to 69% by weight, based on the sum of components (A), (B) and (C), of a copolymer obtainable by polymerizing a mixture consisting of
• (B1) from 75 to 88% by weight, based on (B), of a styrenic monomer and
• (B2) from 12 to 25% by weight, based on (B), of a vinyl cyanide
• and
• (C) from 1 to 40% by weight, based on the sum of components (A), (B) and (C), of a graft copolymer obtainable from
• (C1) from 60 to 90% by weight, based on (C), of a core obtainable by polymerizing a monomer mixture consisting of
• (C11) from 65 to 90% by weight, based on (C1), of a 1,3-diene and
• (C12) from 10 to 35% by weight, based on (C1), of a styrenic monomer
• and
• (C2) from 5 to 20% by weight, based on (C), of a first graft shell and
• (C3) from 5 to 20% by weight, based on (C), of a second graft shell obtainable by polymerizing a monomer mixture consisting of
• (C31) from 70 to 98% by weight, based on (C3), of a C1-C8-alkyl ester of methacrylic acid and acrylic acid
• and
• (D) if desired, customary additives in amounts of up to 20% by weight, based on the sum of components (A), (B) and (C),
• with the proviso that the weight ratio of (C2) to (C3) is in the range from 2:1 to 1:2,
• wherein the first graft shell (C2) is obtainable by polymerizing a monomer mixture consisting of
• (C21) from 30 to 39% by weight, based on (C2), of a styrenic monomer,
• (C22) from 61 to 70% by weight, based on (C2), of a C1-C8-alkyl ester of methacrylic acid and
• (C23) from 0 to 3% by weight, based on (C2), of a crosslinking monomer.