| 摘要 |
Polyurethane foams are prepared by reacting with an active hydrogen-containing compound, a diisocyanate composition of viscosity 20-10,000 cps. at 25 DEG C. and amine equivalent 90-125, which has been prepared by heating at 150-200 DEG C. for 1-5 hours an organic diisocyanate with 0.5-8.5 wt. per cent aromatic diamine dissolved in an organic solvent of lower b.p. than the diisocyanate and simultaneously or subsequently distilling off the solvent. In Example 2, a foam is made from tolylene diisocyanate which has been treated with m-tolylenediamine, using a polyester mixture of OH No. 375-380, [CH2N(C3H6OH)2]2 silicone emulsifier, dibutyltin dilaurate and CFCl3.ALSO:Stable liquid diisocyanate compositions are prepared by heating, at 150-200 DEG C. for 1-5 hours, an organic diisocyanate with 0.5 to 8.5 wt. per cent aromatic diamine dissolved in an organic solvent having a lower b.p. than the diisocyanate, simultaneously or subsequently distilling off the solvent, and recovering the said composition having a viscosity 20-10,000 c.p.s. at 25 DEG C. and an amine equivalent 90-125. In examples, tolylenediisocyanate is treated with m-tolylenediamine or bis-(4-aminophenyl)methane. |
