Extrusion apparatus using perforated member in discharge passage for producing sheet material with multicolor striated pattern

Claim 1

An extrusion assembly for fabricating synthetic plastic sheet material having differentially colored bands with striations therein extending along the length thereof and comprising: a. an extrusion die block having a chamber therein, an elongated extrusion orifice in one surface thereof and a discharge passage between the said chamber and said orifice; b. a first feed conduit to said chamber at a point spaced to the opposite side thereof from said discharge passage for supplying a matrix of fluid synthetic thermoplastic resin; c. at least one additional feed conduit to said chamber having a portion within said die member extending generally parallel to said extrusion orifice for supplying a differentially colored fluid synthetic thermoplastic resin; d. at least one sleeve member within said chamber spaced from said discharge passage and extending generally parallel to said extrusion orifice, said sleeve member having a bore therein communicating with said additional feed conduit, said sleeve having a multiplicity of discharge openings communicating with said bore and opening adjacent said discharge passage; and e. a perforated member in said discharge passage occupying the full depth of said passage and having a multiplicity of perforations therein, at least some of said perforations being closely spaced apart to provide narrow solid segments therebetween, whereby the composite stream passes through the perforations of said perforated member prior to discharge from said orifice and the differentially colored fluid synthetic plastic resin is caused to flow about the narrow solid segments between said perforations.