A process for producing a copolymer latex and paper coating composition, composition for the carpet back coating or adhesive mixture which contains this latex.

摘要

A process for producing a copolymer latex having a gel content of 5% by weight or more, comprising emulsion-polymerizing(a) 2-80% by weight of a conjugated diene compound,(b) 0.1-10% by weight of an ethylenically unsaturated carboxylic acid, and(c) 10-97.9% by weight of an ethylenically unsaturated compound other than the components (a) and (b) in the presence of(d) a chain transfer agent comprising at least one member selected from the group consisting of the following (d-1) to (d-6):(d-1) an a-methylstyrene dimer,(d-2) at least one disulfide compound selected from the group consisting of dimethylxanthogen disulfide, diethylxanthogen disulfide and thiuram disulfide,(d-3) at least one hydrocarbon compound selected from the group consisting of hydrocarbon compounds having an aromatic ring and at least one saturated carbon atom directly bonded to the ring, said carbon atom having bonded thereto at least one hydrogen atom and forming an aliphatic ring, and alicyclic hydrocarbon compounds having in the ring at least two carbon-to-carbon double bonds and at least one saturated carbon atom adjacent to the carbon-to-carbon double bonds and forming the aliphatic ring, said carbon atom having at least one hydrogen atom,(d-4) an unsaturated heterocyclic compound having in the heterocyclic ring a carbon-to-carbon double bond and at least one saturated carbon atom adjacent to the carbon-to-carbon double bond and forming the heterocyclic ring, said carbon atom having at least one hydrogen atom,(d-5) a hydrocarbon compound having at least two unsaturated bonds and at least one saturated carbon atom adjacent to the carbon atoms taking part in the two unsaturated bonds, said saturated carbon atom forming no ring structure and having at least one hydrogen atom, and(d-6) a mixture consisting of (X) 5-95% by weight of at least one compound selected from the group consisting of terpinolene, a-terpinene, y-terpinene and dipentene and (Y) 95-5% by weight of at least one compound selected from the group consisting of alkylmercaptans, halogenated hydrocarbons and disulfide compounds. The copolymer latex produced according to the above process contains fine coagula only in a very small amount, and is suitable for use in paper coating compositions, carpet backing compositions and adhesive compositions.