Method for making composite plastic article

Claim 1

In the process of forming a composite plastic article from a parison having at least two layers of material wherein the parison is formed on a core in a parison mold by molding the organic plastic material around the core in the parison mold cavity and wherein the parison is subsequently expanded in a blow mold, the steps which comprise applying a preformed liner to said core, said liner having substantially continuous side and end portions which conform to the sides and end of the core and prevent direct contact between the core and plastic being molded therearound, subsequently pressure molding an outer layer of organic plastic material around said liner substantially enclosing said liner to form a composite parison by injecting plastic into said mold cavity around said core and liner and causing the injected plastic to fill the space therearound in a manner such that substantially all air in said mold cavity in the space between said core and liner and between the liner and the injected plastic is forced toward the portion last to be filled, venting such air from said portion, bringing said liner to a temperature at which it is capable of being expanded together with said outer layer, at least in part by means of said outer layer, introducing said liner and outer layer into a blow mold in said heated state, and expanding said liner and outer layer in unison to form a multilayered hollow article.