| 摘要 |
PROBLEM TO BE SOLVED: To obtain a high-nitrile content copolymer latex excellent in emulsion stability, film-forming capability and gas barrier properties by subjecting a monomer mixture comprising acrylonitrile and a vinyl monomer in a specified ratio to emulsion polymerization in the presence of a polyvinyl alcohol having specified viscosity and degree of saponification. SOLUTION: This copolymer latex is produced by subjecting 100 pts.wt. monomer mixture comprising 70-95 pts.wt. acrylonitrile and 30-5 pts.wt. at least one copolymerizable vinyl monomer to emulsion polymerization in the presence of 3-25 pts.wt. polyvinyl alcohol having a viscosity (at 20 deg.C with a Brookfield viscometer) of 2-50 mPa.s and a degree of saponification of 95.5 mol% or higher, a polymerization initiator, a surfactant, a reactive emulsifier (e.g. sulfoethyl methacrylate), etc. Examples of the copolymerizable vinyl monomer are (meth)acrylates, (meth)acrylamides, vinyl compounds, olefins, unsaturated carboxylic esters and vinylidene compounds.
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