| 摘要 |
PROBLEM TO BE SOLVED: To obtain a rigid polyurethane foam perfectly foamed by using water without entirely using a fluorocarbon-based blowing agent such as HCFC-141b, HFC, etc., as a blowing agent and having an excellent application, an excellent workability, an excellent dimensional stability and a high strength. SOLUTION: This rigid polyurethane foam is obtained by mixing a polyisocyanate component with a blended solution mixed with a polyol component, water, a catalyst, a foam stabilizer and other auxiliaries in a mixing head and airless spray foaming which allows to foam by using carbon dioxide gas generated by reacting a polyisocyanate component with water as a blowing agent. Water content of the blended solution is 3.0-7.0 wt.%, foaming rate is <5 sec, core density (JISA9526) of the foam is 20-45 kg/m3, closed-cell ratio (ASTM D2856) is >=50% and rate of dimensional change at a high temperature and a high humidity is <=±5%. |
