| 摘要 |
The invention relates to graft copolymers obtainable by
A) Emulsion polymerisation of from 5 to 35% by weight of a monomer mixture comprising
a1) 60-80% by weight of at least one vinyl aromatic monomer,
a2) 20-40% by weight of at least one ethylenically unsaturated nitrile
a3) 0-10% by weight of at least one di- or polyethylenically unsaturated monomer,
and
B) subsequent emulsion polymerisation, in the presence of the emulsion polymer obtained from step A), of 20-45% by weight of a monomer mixture comprising
b1) 50-75% by weight of at least one vinyl aromatic monomer,
b2) 25-50% by weight of at least one C1-C18-alkyl acrylate
b3) 0-10% by weight of at least one di- or polyethylenically unsaturated monomer,
and
C) subsequent emulsion polymerisation, in the presence of the emulsion polymer obtained in step B), of 5-35% by weight of a monomer mixture comprising
c1) 60-80% by weight of at least one vinyl aromatic monomer,
c2) 20-40% by weight of at least one ethylenically unsaturated nitrile
c3) 0-10% by weight of at least one di- or polyethylenically unsaturated monomer,
and
D) subsequent emulsion polymerisation, in the presence of the emulsion polymer obtained in Step C), of 15-45% by weight of a monomer mixture comprising
d1) 80-99.9% by weight of at least one C1-C18-alkyl acrylate,
d2) 0.1-10% by weight of at least one di- or polyethylenically unsaturated monomer.
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