Patent ID: 6989408

Claim:
A method of preparing an acryl-based impact reinforcement comprising the step of blending: a) 50 to 90 parts by weight of latex having large particles with a mean particle size of 200 to 500 nm and a core-shell structure; and b) 10 to 50 parts by weight of latex having small particles with a mean particle size of 60 to 140 nm and a core-shell structure; wherein the core-shell structure of the large particles is formed by a polymerization method comprising: i) polymerization of a first emulsified mixture comprising 97.0 to 99.9 parts by weight of alkyl acrylate having an alkyl group of C 2 to C 8 ; 0.1 to 3.0 parts by weight of cross-linking agent; 0.01 to 3.0 parts by weight of a polymerization initiator; 0.1 to 10.0 parts by weight of an emulsifier; and 1000.0 parts by weight of ion-exchange water at 60 to 80° C. to prepare a first seed comprising a first latex; ii) polymerization of a second emulsified mixture comprising 97.0 to 99.9 parts by weight of alkyl acrylate having an alkyl group of C 2 to C 8 ; 0.1 to 3.0 parts by weight of cross-linking agent; 0.1 to 4.0 parts by weight of an emulsifier; and 80 parts by weight of ion-exchange water, by adding 0.01 to 3.0 parts by weight of a polymerization initiator to the first seed while adding the second emulsified mixture continuously to the seed, to form a second latex; iii) polymerization of a third emulsified mixture comprising 97.0 to 99.9 parts by weight of alkyl acrylate having an alkyl group of C 2 to C 8 ; 0.1 to 3.0 parts by weight of cross-linking agent; 0.1 to 4.0 parts by weight of an emulsifier; and 80 parts by weight of ion-exchange water, by adding 0.01 to 3.0 parts by weight of a polymerization initiator to the second latex while adding the third emulsified mixture continuously to the second latex, to form a third latex; and iv) polymerization of a fourth emulsified mixture comprising 80 to 100 parts by weight of alkyl methacrylate having an alkyl group of C 1 to C 4 ; 10 parts by weight or less of alkyl acrylate selected from the group consisting of ethyl acrylate, methyl acrylate, and butyl acrylate; 10 parts by weight or less of nitrile selected from the group consisting of acrylonitrile, and methacrylonitrile; 0.1 to 4.0 parts by weight of emulsifier; and 150 parts by weight of ion-exchange water, by adding 0.01 to 3.0 parts by weight of a polymerization initiator to the third latex while adding the fourth emulsified mixture continuously to the third latex.