초록 ▼

A polyol composition is provided which when reacted with an organic isocyanate, has good flow characteristics and makes a rigid polyurethane foam having good dimensional stability at low densities. The polyol composition has a polyol component which must have present a polyoxyalkylene polyether poly

A polyol composition is provided which when reacted with an organic isocyanate, has good flow characteristics and makes a rigid polyurethane foam having good dimensional stability at low densities. The polyol composition has a polyol component which must have present a polyoxyalkylene polyether polyol having an equivalent weight of 130 or less and a hydroxyl number of 400 or more, a polyoxyalkylene polyether polyol having an average functionality from 1.5 to 3.1 and a viscosity of less than 800 cP at 25.degree. C., and a polyoxyalkylene polyether polyol having an average functionality of greater than 3.1 and a viscosity of 5,000 cp or less at 25.degree. C. The polyol composition also has formic acid or a mixture of formic acid and water as blowing agents, and further contains a delayed action blow catalyst and a delayed action gel catalyst.

대표청구항 ▼

[ What we claim is:] [1.] A dimensionally stable, rigid polyurethane foam having a core density of 1.0 to 1.8 pcf comprising the reaction product of:a) an organic polyisocyanate andb) a polyol composition and, optionally,c) a chain extender and/or a crosslinking agent the presence ofd) a blowing age

[ What we claim is:] [1.] A dimensionally stable, rigid polyurethane foam having a core density of 1.0 to 1.8 pcf comprising the reaction product of:a) an organic polyisocyanate andb) a polyol composition and, optionally,c) a chain extender and/or a crosslinking agent the presence ofd) a blowing agent ande) a catalyst and, optionally,f) assistants and/or additives, d polyol composition comprising (1) a polyoxyalkylene polyether polyol having an equivalent weight of 130 or less, and an average functionality of 3.1 or greater; (2) a polyoxyalkylene polyether polyol having an average functionality of 1.8 to less than 3.1, a viscosity of 800 cP or less at 25.degree. C., and an equivalent weight within the range of from greater than 130 to 1500; and (3) a polyoxyalkylene polyether polyol having an average functionality of greater than 3.1 and an equivalent weight of greater than 130, said blowing agent comprising a mixture of formic acid and water, wherein said rigid polyurethane foam being dimensionally stable according to the A[ D 2126-87 test method by exhibiting a volume change of .+-.10 percent or less at 158.degree. F. and 100 percent relative humidity, of .+-.7 percent or less at 200.degree. F. and 0.0 percent relative humidity, and of .+-.10 percent or less at -20.degree. F. and 0.0 percent relative humidity, and exhibiting a surface friability of less than 5% according to the A][ C 421 test method.][ D 2126-87 test method by exhibiting a volume change of .+-.10 percent or less at 158.degree. F. and 100 percent relative humidity, of .+-.7 percent or less at 200.degree. F. and 0.0 percent relative humidity, and of .+-.10 percent or less at -20.degree. F. and 0.0 percent relative humidity, and exhibiting a surface friability of less than 5% according to the A][ C 421 test method.][ D 2126-87 test method by exhibiting a volume change of .+-.10 percent or less at 158.degree. F. and 100 percent relative humidity, of .+-.7 percent or less at 200.degree. F. and 0.0 percent relative humidity, and of .+-.10 percent or less at -20.degree. F. and 0.0 percent relative humidity, and exhibiting a surface friability of less than 5% according to the A][ C 421 test method.]