| 摘要 |
A process for the production of a foam material from a liquid curable resole or aminoplast synthetic thermosetting resin comprises incorporating in the liquid resole or aminoplast a heat-operable foaming agent and a solid inorganic compound in an amount of from 3 to 40% by weight based on the resin, such compound being capable of reacting with the water which is present in the resole or aminoplast, or which forms during the curing thereof, with the evolution of sufficient heat to cause the resin to foam and be cured without the necessity for external heating but without the formation of gas. Inorganic compounds specified are acid anhydrides and hydrate-forming salts, for example boron trioxide, phosphorus pentoxide, calcium chloride, lithium chloride, zinc chloride and magnesium perchlorate. They can be dissolved or suspended in anhydrous organic liquids, e.g. benzene, pentane, carbon tetrachloride, dioctyl phthalate, dibutyl phthalate, tricresyl phosphate, trichlorethyl phosphate, glycol, glycerol and liquid polymerization products of coumarone and/or indene. In examples foamed resins are obtained by (1), (2) and (3) mixing a phenol-formaldehyde liquid resole with (1) petroleum ether, hydrochloric acid and phosphorus pentoxide in tricresyl phosphate; (2) n-pentane, hydrochloric acid and boron trioxide in a liquid coumarone resin; (3) pentane, hydrochloric acid and calcium chloride in trichlorethyl phosphate; (4) mixing a liquid aminoplast resin, containing surface-active agent, with petroleum ether, aqueous oxalic acid solution and boron trioxide. |
