| 摘要 |
1303869 Phenolic resin foams DYNAMIT NOBEL AG 2 April 1970 [2 April 1969] 15777/70 Heading C3C A phenolic resin foam is made by foaming a mixture of an aqueous solution and/or suspension of a phenolic resol obtained by condensation of a phenol with an aldehyde in aqueous alkaline medium, a solid or liquid expanding agent, a solid or liquid hardener, a surfactant and 5-50% by wt., based on the resin, of a shrinkreducing agent which is particulate calcium sulphate hemihydrate with optionally anhydrous calcium sulphate and/or calcium sulphate dihydrate, in particulate form. Up to 5% by wt. of the calcium sulphate may be replaced by another calcium salt, a sulphate of an alkali or alkaline earth metal, or of zinc or aluminium, or an alkali metal chloride. The expanding agent may be chloroform, carbon tetrachloride, a chlorofluoromethane, n-pentane, n-butyl ether, petroluem ether, ethylene dichloride or an alkali metal or ammonium carbonate or bicarbonate. The hardener may be a p-toluene sulphonic acid or HCl, with glycol, H 2 SO 4 , boric acid and/ or silicon dioxide. The surfactant may be a polyethylene ether of a monoester of a C 12-18 fatty acid and sorbitol, or a water-soluble ethoxylated castor oil and acts as a cell regulator. In the example the phenolic resins used were phenol/formaldehyde resols in solution in aqueous sodium hydroxide. The foams may be made in open box moulds to form blocks which were then sawn into panels. The foams may be made continuously by foaming the above mixture between the belts of a heated double belt press. |
