Abstract: Disclosed is a process for continuously producing rubber modified styrene resins wherein the rubbery phase including a rubber-like polymer is transformed into dispersed particles by using a reactor having both a helical-blade agitator mounted in a draft tube and an auxiliary agitator, by establishing a specified agitating force and a specified degree of circulation of the fluid within the reactor, and by maintaining a specified relation between the weight percentages, based on the total amount of all components within the reactor, of the rubber-like polymer and the monomer converted to polymer. According to this process, various grades of high-impact rubber modified styrene resins having excellent surface properties can be obtained without any adhesion of rubber-like matter to the reactor and without any formation of fisheyes in final products.

Abstract: A method of manufacturing rubber modified styrene resins comprising the 1st step of polymerizing a styrene monomer in the presence of a butadiene polymer and an organic peroxide at the ratio of 100 parts by weight, 3 to 15 parts by weight and 0 to 0.01 parts by weight respectively until the polymerization yield of the styrene monomer becomes 2 to 5 time more than the weight of the butadiene polymer, and the 2nd step of polymerizing the full amount of polymer mixture from the 1st step and 0 to 200 parts by weight of the fresh styrene monomer in the presence of 0.01 to 0.9 parts by weight of the organic peroxide until the polymerization yield of the styrene monomer becomes at least 1.5 times more than that of the 1st step. The molded product of the resin thus obtained shows an improved impact strength at the portions wherein polystyrene molecule orientation tends to occur.

Abstract: A process for polymerizing a styrene monomer or a styrene monomer having a rubber-like polymer dissolved therein by using, as the catalyst, an organic peroxide of the formula ##STR1## where R.sub.1 and R.sub.2 are the same or different radicals selected from the group consisting of hydrogen, alkyl radicals of from 1 to 5 carbon atoms, and phenyl. Preferably, the polymerization is continuously carried out by bulk or solution polymerization while the reaction mixture present in the polymerization zone is kept in such a mixed state as to make it substantially homogeneous.