Method of manufacturing an injection molded shoe

A method for manufacturing an integrally-formed injection molded shoe article, comprising the steps of:

• coupling a distributing valve to a first extruder and a second extruder;
• connecting a control device comprising a microprocessor to said first extruder, said second extruder and said distributing valve;
• coupling a plurality of sprues of a mold to a corresponding plurality of outlets of said distributing valve via respective supply conduits;
• plasticizing a first synthetic resin material in the first extruder and a second different synthetic resin material in the second extruder;
• controlling the length of time of actuation of each of said first and second extruders, with said control device, to produce different pressures in said extruders;
• operating said distributing valve with said control device, to (i) select at least one outlet and corresponding supply conduit for successively receiving the first and second synthetic resin materials and (ii) control the length of time for said at least one selected outlet and corresponding supply conduit to successively receive the first and second synthetic resin materials;
• injecting the first and second synthetic resin materials successively through the respective sprue into the mold cavity so that the molten first and second synthetic resin materials flow into each other;
• wherein the different synthetic resin materials are injected into the mold cavity at different pressures;
• wherein at least one of the different synthetic resin materials is injected into the mold cavity at a pressure which varies during the injection of the synthetic resin material;
• permitting the injected synthetic resin materials to harden in the mold cavity and permanently bond together to form an integral injection molded shoe article;
• and
• removing the shoe article from the mold cavity.