Process for producing porous object

Abstract

The present invention provides a process for producing porous structure having similar properties to that of the porous structure produced with conventional urethane resin solution in organic solvent and suitable for artificial leather, wherein the environmental pollution in the production process with a urethane resin solution in organic solvent and adverse effect on human health caused from remained organic solvent are solved and the problems caused from nonuniform pores produced with urethane resin emulsion are solved. The present invention also provides a production process for porous structure wherein an aqueous urethane resin emulsion to which a highly crystalline substance comprising of a diisocyanate and low-molecular-weight diol is added, or an aqueous emulsion of urethane resin containing the said highly crystalline substance in its polymer chain is heated and gelled with steam with the presence of a pore-forming agent for stabilizing the gel of the said aqueous urethane resin emulsion in the heating and gelling process, and then the gelled aqueous urethane resin emulsion is heated and dried for forming the space of the water into porous structure. In addition, the present invention also provides a process for producing porous structure wherein an aqueous urethane resin emulsion is heated and gelled with steam with the presence of at least one of those selected from the group comprising silica, colloidal silica, silicic acid and silicate for stabilizing the gel of the said aqueous urethane resin emulsion in heating and gelling, and is heated and dried for forming the space of the water into porous structure.

Dependencies are inferred from the claim text.