Patent ID: 7432320

Claim:
A processing aid for a vinyl chloride resin; the processing aid having a specific viscosity η sp of 0.6-1.6, an average particle diameter of 1500-3000 Å and being obtained by polymerizing 1 to 50 parts by weight of a monomer mixture (B) comprising 0 to 49% by weight of methyl methacrylate, 51 to 100% by weight of at least one monomer selected from the group consisting of a methacrylate ester except methyl methacrylate and an acrylate ester, and 0 to 20 % by weight of a vinyl monomer copolymerizable therewith, in the presence of a latex of a (co)polymer having specific viscosity of at least η sp 0.7, which is obtained by polymerizing in emulsion 99 to 50 parts by weight of a monomer mixture (A) comprising 51 to 100% by weight of methyl methacrylate, 0 to 49 % by weight of at least one monomer selected from the group consisting of a methacrylate ester except methyl methacrylate and an acrylate ester, and 0 to 20 % by weight of a vinyl monomer copolymerizable therewith, the total amount of (A) and (B) being 100 parts by weight, and the specific viscosities being measured at 30° C. using Ubbelohde's Viscometer on 0.1 g of polymer dissolved in 100 mL chloroform.