Thermal decomposition degreasing method and molded products thereof

Abstract

A low-cost thermal decomposition degreasing method capable of drastically reducing the time required for a degreasing process which involves heating, vaporization and thermal decomposition, while assuring the shape retention property of an injection molded product during degreasing. The degreasing process comprises: (i) a first step wherein a molded product placed under a reduced pressure less than or equal to atmospheric pressure is heated at a temperature lower than the melting point of a thermoplastic binder so that the thermoplastic binder partially evaporates by 5 wt % or more, and then the molded product is further heated at a temperature lower than higher one of the melting points of a more volatile organic compound and a thermoplastic resin whereby the thermoplastic binder further evaporates by 10 wt % or more, and wherein the final temperature is set to 200.degree. C. or less; and (ii) a second step wherein the molded product is heated to a temperature higher than or equal to the highest one of the melting points of thermoplastic binder components at a pressure higher than or equal to atmospheric pressure in an atmosphere of gas inert relative to a powder material constituting the molded product.