| 摘要 |
<p>A novel polyurethane free of ether linkages is prepd. from (A) a cycloaliphatic polyisocyanate, (B) an active H-contg. material of mol. wt. 250 and contg. only 2 active H's/molecule, (C) a material like (B) but contg. >=3 active H's/molecule, and opt. (D) a polymeric polycarbonate diol. The equiv. ratio of (B):(C) is from 0.5-10:1, and the product has a calculated wt.% of urethane linkages (Wu) of >=20% and a calculated mol. wt. between branch points (Wf) of 600-4,000. Used esp. for glazing in aircraft, architecture and optical lenses. The polymer can be heat cured to hard impact-resistant articles. The articles have excellent resistance to heat and weathering, and are flexible.</p> |
