| 摘要 |
<p>Elastomeric polyurethanes consisting substantially completely o units of formula <FORM:0989919/C3/1> where T is a divalent organic radical, R is an alkylene radical and Z is a polyester or polyether residue such that the compound HO-Z-OH is a linear, hydroxy terminated polyester or polyether of M.W. 500-2500 having in the case of said polyester a practically zero acid index, are prepared by chain extending a prepolymer with a bis(amino-oxy) alkane of formula H2N-O-R-O-NH2. The polyesters may be derived from acids of formula HOOC(CH2)nCOOH, where n is 2 to 8 and an alkylene glycol of 2 to 4 carbon atoms. The polyethers may be of the polyethylene oxide or polytetrahydrofuran types. Conventional diisocyanates are mentioned including those in which T is of the formula <FORM:0989919/C3/2> In a typical example (5) hexamethylene diisocyanate was reacted with a mixed ethylene glycol propylene glycol adipate polyester, the mixture dissolved in dimethyl formamide and 1,2-diamino-oxyethane added.</p> |
