| 摘要 |
PROBLEM TO BE SOLVED: To produce a halogen-free flame-retardant rigid polyurethane foam expanded with pentane and satisfying the required and specified requirements of high flame-retardance, easy production, low smoke density and low smoke toxicity. SOLUTION: This halogen-free flame-retardant rigid polyurethane foam expanded with pentane contains an oxyalkylated alkylphosphonic acid as a flame- retardant. The alkylphosphonic acid is expressed e.g. by formula (1) (R1 is methyl, ethyl or propyl; R2 and R3 are each same or different and are each methyl, ethyl or propyl; and (x) is 1.2-1.9). |
