| 摘要 |
A shaped polyurethane product having improved arc-resistance, current leakage properties and dimensional stability which adapt it to be used as an electrical insulator is made by shaping a reactive mixture containing A. A POLYISOCYANATE HAVING ONLY CYCLOALIPHATIC ISOCYANATO GROUPS, B. A POLYISOCYANATE HAVING ONLY CYCLOALIPHATIC AND ALIPHATIC ISOCYANATO GROUPS, OR C. A MIXTURE OF (A) OR (B) WITH AN ALIPHATIC POLYISOCYANATE, WITH A POLYOL MIXTURE CONTAINING D. 5 TO 30 PERCENT BY WEIGHT, BASED ON THE TOTAL WEIGHT OF THE POLYOL MIXTURE OF A POLYOL OR POLYOL MIXTURE HAVING A MOLECULAR WEIGHT BELOW ABOUT 1000 IN WHICH THE HYDROXYL GROUPS ARE ONLY CYCLOALIPHATICALLY OR ALIPHATICALLY BOUND AND AT LEAST 50% THEREOF ARE CYCLOALIPHATICALLY BOUND; AND E. 70 TO 90 PERCENT BY WEIGHT OF A POLYOL OR POLYOL MIXTURE HAVING A MOLECULAR WEIGHT BELOW 1000 IN WHICH THE HYDROXYL GROUPS ARE SUBSTANTIALLY ALL ALIPHATICALLY BOUND. |
