Patent ID: 7608656

Claim:
A process for producing an emulsion pressure-sensitive adhesive, which process comprises (co)polymerizing a monomer having a polymerizable unsaturated bond based on alkyl acrylates as a main component in an aqueous medium containing a surface active agent in the presence of a protective colloid, the protective colloid being an acrylic copolymer consisting essentially of: (A-1) at least one hydrophilic monomer selected from the group consisting of acrylamide, methacrylamide, hydroxyethyl acrylate and hydroxyethyl methacrylate; (B-1) an alkyl (meth)acrylate that is copolymerizable with the hydrophilic monomer (A-1) and whose alkyl group has 4 to 18 carbon atoms; and (C) a third monomer being acrylonitrile and/or styrene; the hydrophilic monomer, the alkyl (meth)acrylate and the third monomer being copolymerized in a weight ratio (A-1):[(B-1)+(C)] in the range of 40-70:60-30 and in a weight ratio (B-1):(C) in the range of 99.9-20:0.1-80; the acrylic copolymer having a weight-average molecular weight in the range of 500 to 50000.