They are synthesized by the reaction of a polyester polyol, or polyether polyol, with an aromatic or aliphatic isocyanate. 他們由一種聚酯多羥基化合物或聚醚多羥基化合物與另一種芳香或脂肪族異氰酸鹽的反應而合成。
Such agents have low boiling points and boil from the heat generated during the exothermic reaction between isocyanate and polyol. 這樣代理有低落沸點和煮沸從熱引起在放熱反應期間在異氰酸鹽和多羥基化合物之間。