Patent ID: 7497979

Claim:
A method of forming a sheet of a melt-processable thermoplastic composition having a first surface and second opposite surface wherein said first surface exhibits a lower gloss than said second surface, the method comprising extruding a melt-processable thermoplastic composition comprising: (a) 50-99.5 wt % of a melt-processable thermoplastic polymer; and (b) 0.5 to 50 wt % of a particulate polymer comprising a homopolymer of methyl methacrylate or a copolymer comprising the residues of a monomer mixture comprising at least 50 wt % methyl methacrylate and up to 50 wt % of a copolymerisable acrylic comonomer comprising at least one alkyl acrylate or methacrylate and 0 to 10 wt % of a copolymerisable cross-linking monomer, said particles having a maximum dimension of 5 mm; and calendaring the extruded thermoplastic composition with calendaring rolls to form said sheet, whereby said first surface of the sheet contacts said calendar rolls for a shorter period of time than said second surface.