Provided is a polymer production method including: batch-adding a reaction solution including a monomer mixture including a maleimide-based monomer, a vinyl aromatic monomer, and a vinyl cyanide-based monomer and an aqueous solvent to a reactor and initiating polymerization; and carrying out the polymerization while continuously adding the maleimide-based monomer and the aqueous solvent to the reactor, wherein the reaction solution satisfies the above Formula 1.

Provided is a polymer production method including: batch-adding a reaction solution including a monomer mixture including a maleimide-based monomer, a vinyl aromatic monomer, and a vinyl cyanide-based monomer and an aqueous solvent to a reactor and initiating polymerization; and carrying out the polymerization while continuously adding the maleimide-based monomer and the aqueous solvent to the reactor, wherein the reaction solution satisfies the above Formula 1.

Provided is a polymer production method including: batch-adding a reaction solution including a monomer mixture including a maleimide-based monomer, a vinyl aromatic monomer, and a vinyl cyanide-based monomer and an aqueous solvent to a reactor and initiating polymerization; and carrying out the polymerization while continuously adding the maleimide-based monomer and the aqueous solvent to the reactor, wherein the reaction solution satisfies the above Formula 1.

Provided is a method of preparing a graft copolymer, which includes: preparing a liquid maleimide-based monomer; preparing a reaction solution including a diene-based rubber polymer, an aromatic vinyl-based monomer, and a vinyl cyan-based monomer; and adding the liquid maleimide-based monomer and the reaction solution to a reactor and carrying out polymerization. According to the preparation method of the present invention, the amount of the maleimide-based monomer involved in the polymerization can be increased, and the color characteristics, glass transition temperature, and softening temperature of the graft copolymer are improved.

Provided is a method of preparing a graft copolymer, which includes: preparing a liquid maleimide-based monomer; preparing a reaction solution including a diene-based rubber polymer, an aromatic vinyl-based monomer, and a vinyl cyan-based monomer; and adding the liquid maleimide-based monomer and the reaction solution to a reactor and carrying out polymerization. According to the preparation method of the present invention, the amount of the maleimide-based monomer involved in the polymerization can be increased, and the color characteristics, glass transition temperature, and softening temperature of the graft copolymer are improved.

The present invention provides a maleimide-based copolymer, a method for producing same, and a resin composition obtained using same.

This maleimide-based copolymer contains 40-60 mass % of aromatic vinyl monomer units, 5-20 mass % of vinyl cyanide monomer units, and 35-50 mass % of maleimide monomer units, and is such that a 4 mass % tetrahydrofuran solution of the copolymer has a transmittance of 90% or more for light having a wavelength of 450 nm at an optical path length of 10 mm, and the residual maleimide-based monomer amount is less than 300 ppm. This maleimide-based copolymer preferably further contains 0-10 mass % of unsaturated dicarboxylic acid anhydride monomer units, and preferably has a glass transition temperature of 165° C. or higher.

The present invention provides a maleimide-based copolymer, a method for producing same, and a resin composition obtained using same.

This maleimide-based copolymer contains 40-60 mass % of aromatic vinyl monomer units, 5-20 mass % of vinyl cyanide monomer units, and 35-50 mass % of maleimide monomer units, and is such that a 4 mass % tetrahydrofuran solution of the copolymer has a transmittance of 90% or more for light having a wavelength of 450 nm at an optical path length of 10 mm, and the residual maleimide-based monomer amount is less than 300 ppm. This maleimide-based copolymer preferably further contains 0-10 mass % of unsaturated dicarboxylic acid anhydride monomer units, and preferably has a glass transition temperature of 165° C. or higher.

The present invention provides a maleimide-based copolymer, a method for producing same, and a resin composition obtained using same.

This maleimide-based copolymer contains 40-60 mass % of aromatic vinyl monomer units, 5-20 mass % of vinyl cyanide monomer units, and 35-50 mass % of maleimide monomer units, and is such that a 4 mass % tetrahydrofuran solution of the copolymer has a transmittance of 90% or more for light having a wavelength of 450 nm at an optical path length of 10 mm, and the residual maleimide-based monomer amount is less than 300 ppm. This maleimide-based copolymer preferably further contains 0-10 mass % of unsaturated dicarboxylic acid anhydride monomer units, and preferably has a glass transition temperature of 165° C. or higher.

Provided is a heat-resistant resin composition which includes: a graft copolymer prepared by graft polymerization of a diene-based rubber polymer with an aromatic vinyl-based monomer and a vinyl cyan-based monomer; a first styrene-based copolymer including a maleimide-based unit and an aromatic vinyl-based unit; a second styrene-based copolymer including a vinyl cyan-based unit and an aromatic vinyl-based unit; and a third styrene-based copolymer including a vinyl cyan-based unit and an aromatic vinyl-based unit, wherein the second styrene-based copolymer and the third styrene-based copolymer include a vinyl cyan-based unit in mutually different amounts.

Provided is a heat-resistant resin composition which includes: a graft copolymer prepared by graft polymerization of a diene-based rubber polymer with an aromatic vinyl-based monomer and a vinyl cyan-based monomer; a first styrene-based copolymer including a maleimide-based unit and an aromatic vinyl-based unit; a second styrene-based copolymer including a vinyl cyan-based unit and an aromatic vinyl-based unit; and a third styrene-based copolymer including a vinyl cyan-based unit and an aromatic vinyl-based unit, wherein the second styrene-based copolymer and the third styrene-based copolymer include a vinyl cyan-based unit in mutually different amounts.