| 摘要 |
An aqueous solution of water-soluble amino resin precondensates is condensed with organic isocyanates, firstly amines and/or organometallic compounds being added to the organic isocyanate, and simultaneously, but separately from one another, a solution of the amino resin precondensate and acidic curing catalysts then being added to the mixture. Foaming inevitably occurs during this operation. The process enables the preparation of, in particular, lightweight foams without the use of particular foaming (blowing) agents. Three different catalyst groups act in concert, with no mutual inhibition. An appropriate choice of the amino resin component, the water content, the amount of polyisocyanate and the combination of the acidic, basic or organometallic catalysts makes it possible to produce, in an economical manner and in a single step and a short production time, foams having good fire and insulation properties which cure tack-free without further thermal aftertreatment. |
