| 摘要 |
1470953 Foamed aqueous urea-formaldehyde resins IMPERIAL CHEMICAL INDUSTRIES Ltd 26 April 1974 [26 Jan 1973] 4127/73 Headings C3C and C3R A foamed aqueous curable urea-formaldehyde resin composition has an acid hardener comprising an organic hydroxy acid, e.g. malic, tartaric and/or citric acid, and optionally an alkyl aryl sulphonic acid, e.g. dodecyl benzene sulphonic acid, and is used to thermally insulate walls by injecting the foam into the cavity of a wall and allowing the resin to be cured by the hardener while in the foamed condition. The foam may be made by blowing an aqueous solution comprising 0À3-2À0% by wt. of the hydroxy acid and 0À5-1À5% by weight of the sulphonic acid through a foaming gun so as to form a foam and spraying an aqueous solution comprising 20-46% by wt. of the resin into the foam as it leaves the gun, the proportions of the 2 solutions being 2 : 1 to 1 : 2 by vol., and allowing the resin to be cured by the acids while in a foamed configuration. |
