Patent GB-912967-A (GB)
Title: An improved process for the preparation of an epoxy resin foam
IPC: C08J9/14
Filed: 1960-07-12
Abstract: Epoxy resin foams are produced by preparing a liquid mixture of (1) one or more polyepoxides having an epoxy equivalent greater than 1,0, (2) one or more fluids of boiling points up to 100 DEG C. which are completely soluble in the liquid mixture at atmospheric temperature and pressure and which vaporize from the liquid mixture at elevated temperatures and (3) one or more fast acting epoxy curing catalysts-and permitting the heat produced by the curing reaction to vaporize said fluid(s) and result in a cured foam.  Normally liquid glycidyl ethers of polyhydric phenols and alcohols are the preferred polyepoxides and these are preferably used in conjunction with epoxy esters of which many are specified; numerous types of polyepoxides in general are specified.  Fast curing agents particularly mentioned are boron trifluoride and its complexes, especially the addition products of boron trifluoride with polyhydric polyethers; phosphoric acid and esters and aliphatic amines such as diethylene triamine.  Many vaporizable fluids are specified, but particularly mentioned are the chlorofluoroalkanes, especially trichlorofluoromethane. Optional additives are thixotropic agents asbestos floc, silicate clays, micas, colloidal silica, organic complexes of bentonite, e.g. the quaternary ammonium bentonite complexes, metallic stearates, oleates and laurates, metallic leafing powders, attapulgite and finely-divided vegetable oil derivatives: surface-active agents such as those known under the Registered p  Trade Marks "Span" and "Tween" as well as polyoxyglycols: fluidizing solvents such as acetone, methyl ethyl ketone, toluene, xylene, ethyl acetate, butyl acetate, chloroform and trichloropropane: and flame-proofing additives such as chlorendic anhydride and antimony trioxide.  The examples describe polyethers prepared from bisphenol and epichlorohydrin, a polyether prepared from 1,1,2,2,-tetrabis-(hydroxyphenyl) ethane, a polyether in which epichlorohydrin itself provides the repeating unit, a polyglycidyl ester of a mixture of dimer and trimer long chain aliphatic acids and a polyepoxide which is the reaction product of (a) a polyether prepared from bis-phenol and epichlorohydrin and (b) the polyglycidyl ester referred to above; foamable mixtures based on one or more of these polyepoxides; and the preparation of cured foams from these mixtures.  Specification 730,670 is referred to.ALSO:Epoxy resin foams are produced by preparing a liquid mixture of (1) one or more polyepoxides having an epoxy equivalent greater than 1,0, (2) one or more fluids of boiling points up to 100 DEG C. which are completely soluble in the liquid mixture at atmospheric temperature and pressure and which vaporize from the liquid mixture at elevated temperatures, and (3) one or more fast-acting epoxy curing agents and permitting the heat produced by the curing reaction to vaporise said fluid(s) and result in a cured foam. Normally liquid glycidyl ethers of polyhydric phenols and alcohols are the preferred polyepoxides and these are preferably used in conjunction with epoxy esters of which many are specified; numerous types of polyepoxides in general are specified.  Fast curing agents particularly mentioned are boron trifluoride and its complexies, especially the addition products of boron trifluoride with polyhydric polyethers; phosphoric acid and esters and aliphatic amines such as diethylene triamine.  Many vaporizable fluids are specified, but particularly mentioned are the chlorofluoroalkanes, especially trichlorofluoromethane. Optional additives are thixotropic agents, e.g. asbestos floc, silicate clays, micas, colloidal silica, organic complexies of bentonite, e.g. the quaternary ammonium bentonite complexes, metallic stearates, oleates and laurates, metallic leafing powders, attapulgite and finely divided solidified vegetable oil derivatives; surface active agents, e.g. those known under the Registered Trade Marks "Span" and "Tween" as well as polyoxyglycols; fluidising solvents, e.g. acetone, methyl ethyl ketone, toluene, xylene, ethyl acetate, butyl acetate, chloroform and trichloropropane; and flame-proofing additives such as chlorendic anhydride and antimony trioxide.  The examples describe polyethers prepared from bis-phenol and epichlorohydrin, a polyether prepared from 1, 1, 2, 2-tetrakis-(hydroxyphenyl) ethane, a polyether in which epichlorohydrin itself provides the repeating unit, a polyglycidyl ester of a mixture of dimer and trimer long chain aliphatic acids and a polyepoxide which is the reaction product of (a) a polyether prepared from bis-phenol and epichlorohydrin and (b) the polyglycidyl ester referred to above; foamable mixtures based on one or more of these polyepoxides; and the preparation of cured foams from these mixtures.  Specification 730,670 is referred to.