| 摘要 |
PURPOSE:To obtain the title lowly hygroscopic, thermosetting resin, by the cast polymerization of a specified polyisocyanate compound and a polythiol compound. CONSTITUTION:A polyisocyanate compound (A) having m (m>=2) NCO groups in the molecule (e.g., isophorone diisocyanate) and a polythiol compound (B) having n (n>=2) SH groups in the molecule [e.g., pentaerythritol tetrakis(3- mercaptopropionate)] are selected so that the value of m+n may be equal to 5 or greater and that the molar ratio between the functional groups, NCO/SH, may be 0.5-3.0, and the selected compounds are cast polymerized at 30-120 deg.C for 3-48hr in the presence of, optionally, 0.01-1.0wt.% polymerization catalyst and 10-5,000ppm of a mold release.
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