PURPOSE: To prevent occurrence of the bubbles or abnormal foaming in a product, while generated moisture is removed in the early stages by mixing an addition agent which has azeotropic effect with water and contains hydrophilic group, in a mold release agent composed of main agent and volatile solvent.
CONSTITUTION: A mold release agent composed of main agent and volatile solvent is the mold release agent for urethane molding having at least azeotropic effect with water and containing addition agent with hydrophilic group. As the main agent paraffin-type silicone-type, fluorine resin-type and polyvinyl alcohol-type, etc. are used. As the typical volatile solvent, cyclohexane, mineral, toluene xylene, etc. are used. As the addition agent, for instance, a lower ketone with about 120 or more molecular weight suck as aceton and methyl ethyl ketone, and lower alcohol, benzene and chloroform, etc. with about 120 or less molecular weight such as ethanol, methanol and isopropanol, etc. are used. The moisture generated in the vaporization of the solvent is mixed with the addition agent, and the boiling points of both materials are lowered, thereby accelerating the vaporization of moisture. The bubble occurrence in the product which is injection molded or cast molded is prevented.