PURPOSE: To prepare the titled composition giving a rigid polyurethane foam having excellent low temperature dimensional stability and excellent physical properties such as low density, high rigidity, etc., by modifying a polyol with urea.
CONSTITUTION: (A) A poly(oxyalkylene)polyol (e.g. adduct of ethylene glycol and alkylene oxide) and/or a low molecular weight polyol (e.g. ethylene glycol) are charged into, e.g. a rotary evaporator, mixed with (B) urea, and made to react under heating and stirring, pref. under reduced pressure, to obtain the objective composition. The reaction temperature is esp. pref. 130W200°C, and the generated ammonia gas is pref. removed completely from the reaction system. The amount of urea is pref. in excess in order to proceed the reaction sufficiently.
ISHIWAKA TAKUMI
USUI KYOSHI
AKAHO MASAYUKI
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