Low-gloss blends containing poly(meth)acrylate rubber-based graft copolymer and process for making thereof

A method of controlling the surface gloss of an extrudable composition of:

• (a) 30-70 parts by weight of a polyvinyl chloride polymer and (b) a graft copolymer comprising a discontinuous poly(alkyl(meth)acrylate) rubber phase having a weight average particle size of 50 to 800 nanometers and a rigid thermoplastic phase wherein at least about 10 weight % to about 90 weight % of rigid thermoplastic phase is chemically grafted to the poly(alkyl(meth)acrylate) rubber phase, the graft copolymer having a glass transition temperature of 25° C. or less,
• said method comprises the steps of (1) extruding the composition, and (2) regulating the swell index of the rubber phase in component (b) to at least about 8 to about 20 by controlling the amount of a polyethylenically unsaturated monomer in an amount of about 0.10 to 0.40 parts by weight per 100 parts by weight of alkyl(meth)acrylate monomer in an emulsion polymerization reaction preparing the poly(alkyl(meth)acrylate) rubber phase in order to vary the surface gloss after extrusion in inverse proportion to the swell index.