초록 ▼

An improved rotational molding apparatus and method are provided for rotational molding of plastic articles having differently colored sections. The method and apparatus use a rotational mold having first and second mold shells separated by a removable partition member to form first and second inter

An improved rotational molding apparatus and method are provided for rotational molding of plastic articles having differently colored sections. The method and apparatus use a rotational mold having first and second mold shells separated by a removable partition member to form first and second interior spaces within the mold. A thin blade is held against the inner surface of at least one of the mold shells to define a plurality of compartments within the respective interior spaces. Differently colored molding materials, preferably plastic powders, are introduced into each of the compartments and caused to melt against the inner surfaces of the mold shells. The surfaces of the blade and the partition member are kept at a lower temperature than the inner surfaces of the mold shells to prevent the molding materials from melting against the surfaces of the blade and the partition member. The partition member and blade are then removed by separating the first and second mold shells, and additional non-colored, plastic powder is added to the mold. The rotational mold is then closed, heated and rotated to cause the plastic powder to melt against the colored plastic powders on the inner surfaces of the mold shells. The result is a rotationally molded plastic article having controlled placement of differently colored molding materials and a nearly seamless interface between the differently colored sections.

대표청구항 ▼

1. A method of making hollow multi color molded articles, comprising the steps of:providing a mold having two separable portions which are useable together to define an enclosed interior space; placing a partition between the two separable portions to divide said enclosed interior space into first a

1. A method of making hollow multi color molded articles, comprising the steps of:providing a mold having two separable portions which are useable together to define an enclosed interior space; placing a partition between the two separable portions to divide said enclosed interior space into first and second interior spaces; separating at least one of said first and second interior spaces into first and second compartments by engaging a blade against an inner surface of a respective one of said mold portions; introducing a first molding material into said first compartment, said first molding material having a first color; introducing a second molding material into said second compartment, said second molding material having a second color different from said first color; heating and moving said mold to cause said first and second molding materials to melt against said inner surface separately from one another without adhering to said blade; removing said blade and said partition from said enclosed interior space; introducing a third molding material into said enclosed interior space; heating and moving said mold to cause said third molding material to melt against exposed inner surfaces of the first and second molding materials and the mold portions to form a hollow molded article; and removing said first and second mold portions from the hollow molded article after the third molding material cools and solidifies.