Patent ID: 11939413
Assignee: MITSUBISHI CHEMICAL CORPORATION
Field: Macromolecular chemistry, polymers (Chemistry)
Classification: CPC C | IPC C

Claim 5:
6. A method for producing the acrylic resin powder according to claim 1, comprising:
performing polymerization to form a polymer (B) by dropwise adding a monomer mixture (b) to a polymer dispersion (Al) that contains a polymer (A) obtained by polymerizing a monomer mixture (a) containing 50% to 60% by mass of methyl methacrylate and an alkyl (meth)acrylate ester (ma) and a chain transfer agent of 0.1 to 3 parts by mass with respect to 100 parts by mass of the monomer mixture (a), to obtain a polymer dispersion (M1) that contains the multi-stage polymer (M) that includes the polymer (A) and the polymer (B); and
spray-drying the polymer dispersion (M1) containing the multi-stage polymer (M) to obtain an acrylic resin powder,
wherein
the monomer mixture (h) comprises:
50% to 90% by mass of methyl methacrylate
10% to 50% by mass of an alkyl (meth)acrylate ester (mb),
0% to 10% by mass of a copolymerizable monomer different from methyl methacrylate and the alkyl (meth)acrylate ester (mh), and
a chain transfer agent of 0.1 to 3 parts b mass with respect to 100 parts by mass of the monomer mixture (b),
the alkyl group of the alkyl (meth)acrylate ester (ma) has 4 to 8 carbon atoms, and
the alkyl group of the alkyl (meth)acrylate ester (mb) has 4 to 8 carbon atoms.