| abstract |
A co-extruded sheet made from olefin polymer materials includes (1) at least one outer layer of (a) a propylene polymer having a melt flow rate of 0.5-15 dg/min, or a graft copolymer comprising a backbone of a propylene polymer material, to which is graft polymerized a vinyl monomer, and (b) a nucleatin g agent having a melting point greater than 265 ~C and (2) another layer made from (a) about 5 % to about 50 % of a high melt strength propylene homopolym er or copolymer, and/or about 5 % to about 40 % of chopped glass fibers, (b) optionally about 5 % to about 40 % of an inorganic filler, (c) about 2 % to about 50 % of an olefin polymer composition, and (d) optionally about 5 % to about 70 % of one or more other olefin polymer materials. When the second layer is reinforced with glass fibers, the stiffness of the sheet is increas ed while maintaining impact strength. The sheet has high surface gloss and good chemical resistance, and can be thermoformed using a melt phase thermoformin g process wherein the surface temperature of the nucleated propylene polymer layer is from at least 310 ~F. |