| abstract |
A process for producing a finely cellular polyurethane foam by mixing a first ingredient comprisi an isocyanate compound and a second ingredient comprising a compound containing an active hydrogen group, characterized by comprising adding a nonionic silicone surfactant containing no hydroxyl group to at least one of the first ingredient and the second ingredient in an amount of 0.1 to 5 wt %, excluding 5 wt %, based on the total amount of the first ingredient and the second ingredient, subsequently agitating the surfactant containing ingredient together with an unreactive gas to disperse the unreactive gas as fine bubbles to prepare a bubble dispersion and then mixing the bubble dispersion with the remaining ingredient to cure the resultant mixture. Thus, a polyurethane foam having uniform fine cells and a higher hardness than ones having the same density can be produced without using a chemically reactive blowing agent such as water, vaporizable expandable blowing agent such as fluorocarbon, or other substance such as a finely particulate hollow foam or solvent soluble substance. |