| 摘要 |
Method of producing a substantially chemically stable urea-formaldehyde foam which comprises preparing a partially cured aqueous urea-formaldehyde resin, modifying the partially cured resin by reacting at pH 4.5 - 5.5 and 70 DEG -110 DEG C with aqueous dialdehyde containing two to six molecular carbons and additional urea with each additive amounting to 1-5 per cent by weight of the modified resin, neutralizing the modified resin to pH 6.7 - 7.5 by addition of aqueous alkali hydroxides or carbonates, combining said neutral modified resin with a froth produced by forcing air through a dilute acidic aqueous surfactant solution to re-activate and complete the cure of the modified resin in the foam, and drying the foam.
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