| 摘要 |
PROBLEM TO BE SOLVED: To obtain a viscosity-reducing agent which, when used in a system using water as a blowing agent in the field of the production of a polyurethane, is highly safe, has a viscosity-reducing effect even in a small amount, is highly compatible with a polyol, and does not adversely affect the properties of a urethane foam by using dibenzyl ether as the principal component. SOLUTION: This agent comprises dibenzyl ether and, optionally, a compound of the formula. The ratio of the dibenzyl ether to the compound of the formula is 100/0 to 100/300 by weight. In the formula, R is H or methyl; and (n)is 1-5. In use, the agent is added to a polyol mixture containing water as a blowing agent and used for the production of a rigid polyurethane foam. For example, in the production at an NCO/OH equivalent ratio of 1.1, it is added in an amount of 2-50 pts.wt. to 100 pts.wt. starting polyol. The amount of water used is 2-10 pts.wt. per 100 pts.wt. polyol.
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