Method for injection molding multi-layer plastic products and multi-layer plast ic products thereof

Abstract

The invention refers to the construction and the procedure for injection molding multi-layer plastic products. The procedure is to first injection mold the first layer ( 1 ) with ribbed protrusions ( 12 ). In the closed product structure, the segments ( 1', 1'' ) of the first layer ( 1 ), with an opening ( 11 ) shaped with a solid core or in any other known way, are joined into a skeleton via inlets ( 13 ), with coupling or in any other known way. First formed layer ( 1 ) is then precisely positioned into the next mold, and over the whole, or a part of the outer surface another layer ( 2 ) is injection molded, whose opposite ribs ( 21 ) fill in the cavities between the ribs ( 12 ), and the ribs ( 22 ) now protrude out of the surface of layer ( 2 ). Layer ( 1 ) over-molded with by the layer ( 2 ) is then positioned into the next mold and the whole procedure is repeated until the desired layer (n) is injection molded whose ribs (n 1 ) fill in the cavities or indentations of the previous layer, while on the surface of the layer (n) grooves (nu) are formed. The layer (n), which contains all the previous layers, is positioned in the last mold where the covering / finishing thin layer (p) is injection molded, whose ridges (pi) fill-in the grooves (nu) of the layer (n), while the outer surface of the layer (p), i.e. of the product, is smooth, or coarse if necessary, or profiled in a desired pattern or design.

Description

technical field [0001] The invention relates to the processing and handling of plastic substances and materials in a plastic state, and covers multilayer articles. [0002] According to the International Patent Classification (IPC), the invention is classified under: Class B 29C 45 / 14, concerning injection molding of inserts; Class B 29C 45 / 16, concerning injection molding of multilayer or multicolor articles; B 29 C 63 Class / 00, concerning over-molding of prefabricated layers; Class B 23B 33 / 00, concerning multilayer parts. Background technique [0003] The present invention solves the problems of multilayer injection molding, so that the articles made in this way have good mechanical properties (such as impact resistance, scratch resistance and fracture resistance) and good ornamental and decorative properties (such as good surface gloss or soft to the touch), and are inexpensive to manufacture. Fabrication and design of individual layers, structural bonding of componen...

AI Technical Summary

Problems solved by technology

This method of molding multi-layered objects uses extremely complex apparatus and molds, as well as complex multi-tube nozzles

Additionally, extremely complex control of the viscosity, flow and temperature of the materials to be molded into the layers is required, all of which further complicate the overall process, resulting in inaccuracies, inefficiencies and increased costs

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