A number of polyester modified rosin with foam formulations have been utilized to prepare rigid urethane foams.
若干聚酯改性松香及其泡沫配方已用于制备硬质尿烷泡沫。
2
Lastly, of course, the main reaction of interest is the formation of urethane groups by reaction of isocyanate groups and hydroxy - groups of the polyester or polyether.