Process for producing molded article

Abstract

A process for producing a molded article comprised of polyurethane is provided, comprising the steps of pouring or injecting a liquid molding material into a mold under the condition that the contact angle between the liquid molding material and the inner surface of the mold is adjusted to not more than 30° by applying the surface-treating agent to the inner surface of the mold, and curing the liquid molding material. A surface-treating agent is also provided which reduces the contact angle between the liquid molding material and a flat plate made of the same material as the mold to not more than 30°. when the surface-treating agent is applied to the flat plate and the liquid molding material is dropped thereon.

1 . A process for producing a molded article made of a polyurethane comprising, 
 (A) pouring or injecting a liquid molding material into a mold under the condition that the contact angle between the liquid molding material and the inner surface of the mold is adjusted to not more than 30° by applying the surface-treating agent to the inner surface of the mold, and    (B) curing the liquid molding material.    
     
     
         2 . The process according to  claim 1 , wherein the molded article is a shoe sole made of a polyurethane foam.  
     
     
         3 . The process according to  claim 1 , wherein the contact angle-reducing substance is an ester prepared from a fatty acid and a monohydric alcohol.  
     
     
         4 . The process according to  claim 1 , wherein the contact angle between the liquid molding material and the inner surface of the mold is adjusted to not more than 23°.  
     
     
         5 . The process according to claims  1 , wherein a mold releasing agent is applied to the inner surface of the mold prior to pouring or injecting the liquid molding material in the mold.  
     
     
         6 . A surface-treating agent used for applying the surface-treating agent to the inner surface of the mold in a process for producing a molded article comprising pouring or injecting a liquid molding material into a mold and curing the liquid molding material, comprising a contact angle-reducing substance which reduces the contact angle between the liquid molding material and a flat plate made of the same material as the mold to not more than 30°, when the surface-treating agent is applied to the flat plate and the liquid molding material is dropped thereon.  
     
     
         7 . The surface-treating agent of  claim 6 , wherein the molded article is a shoe sole made of a polyurethane foam.  
     
     
         8 . A method for reducing surface voids during molding, comprising using the surface-treating agent as defined in  claim 6 .  
     
     
         9 . A method for reducing surface voids during molding, comprising using the surface-treating agent as defined in  claim 7.