Transparent thermoplastic resin composition, production method therefor, molded article obtained by molding transparent thermoplastic resin composition, and production method for molded article

A transparent thermoplastic resin composition comprising:

• based on 100 parts by mass of the transparent thermoplastic resin composition,
• 10 to 60 parts by mass of a graft copolymer (A) obtained by graft copolymerizing a monomer mixture (a) containing at least an aromatic vinyl-based monomer (a1) and a (meth)acrylic acid ester-based monomer (a2) in the presence of a rubbery polymer (R);
• 40 to 90 parts by mass of a vinyl copolymer (B) obtained by copolymerizing a monomer mixture (b) containing at least an aromatic vinyl-based monomer (b1) and a (meth)acrylic acid ester-based monomer (b2);
• 100 to 1,000 ppm of a phenolic compound (C);
• and
• a dihydrooxaphosphaphenanthrene-based phosphorus compound (D),
• wherein a molar ratio (P/OH) of a phosphorus atom (P) of the dihydrooxaphosphaphenanthrene-based phosphorus compound (D) to a hydroxyl group (OH) of the phenolic compound (C) is 0.2 to 5.0.

A method of producing a transparent thermoplastic resin composition, comprising:

• obtaining 10 to 60 parts by mass of a graft copolymer (A) obtained by graft copolymerizing a monomer mixture (a) containing at least an aromatic vinyl-based monomer (a1) and a (meth)acrylic acid ester-based monomer (a2) in the presence of a rubbery polymer (R);
• obtaining 40 to 90 parts by mass of a vinyl copolymer (B) obtained by copolymerizing a monomer mixture (b) containing at least an aromatic vinyl-based monomer (b1) and a (meth)acrylic acid ester-based monomer (b2);
• where a total of the graft copolymer (A) and the vinyl copolymer (B) is 100 parts by mass, and
• mixing at least the graft copolymer (A), the vinyl copolymer (B), a phenolic compound (C), and a dihydrooxaphosphaphenanthrene-based phosphorus compound (D).