Patent GB-995382-A (GB)
Title: A process for the preparation of foamed polymeric materials of cellular form; and the resulting polymeric materials and articles made therefrom
Inventor: CHEN HAROLD HSIAO-JEN
IPC: C08G59/30
Filed: 1962-04-17
Abstract: A process for preparing a foamed polymeric material of cellular form comprises mixing (1) a liquid epoxy reactant having an epoxy equivalent greater than 1.0; (2) a trialkoxyboroxine containing 1 to 4 carbon atoms in each alkoxy group; and (3) either a primary or secondary amine.  The alcohol reaction product of the trialkoxy-boroxine with the amine is sufficiently volatile under reaction conditions to act as a blowing agent.  Its action may be augmented by incorporation of an auxiliary blowing agent such as a gas, e.g. air or a volatile organic liquid, for example, hydrocarbons, alcohols and polychlorofluoromethanes and ethanes. Both blowing agents are eliminated from the structure of the foamed resin. Suitable blowing agents are defined in Specification 974,169. Semi-rigid products are obtained when a polyalkylene diol or triol of nominal molecular weight above 500 or 750, respectively, is incorporated in the reaction mixture. The polyepoxides may be aliphatic, cycloaliphatic, aromatic or heterocyclic and may contain substituents, e.g. chlorine or alkoxy groups.  Specified are dipropylene glycol diepoxide, epoxidized soyabean oil, butadiene dioxide, 1,4- or 1,3-bis(2,3-epoxypropoxy) benzene, 1,8 - bis - (2,3 - epoxypropoxy) octane, 1,4 - bis - (3,4 - epoxybutoxy)-2-chlorocyclohexane, diglycidyl ether, 1,3-bis-(2 - hydroxy - 3,4 - epoxybutoxy) benzene, and 1,2,5,6-diepoxyhexane. Also specified are monomeric and polymeric glycidyl ethers obtained from, e.g. epichlorhydrin and a polyhydric alcohol or phenol; polyepoxypolyhydroxy polyethers; polyepoxy polyethers obtained by reacting, preferably with an axis catalyst, a halogen-containing epoxide with a polyhydric alcohol and treating the product with a base, e.g. sodium aluminate; polymers and copolymers of epoxy-group containing monomers containing in the molecule at least one polymerizable ethylenic linkage.  Specified amines are diethylamine, butylamine, methylaniline, aniline, 1,6-hexanediamine, diethylenetriamine, triethylene tetramine, tetra-ethylenepentamine, 1,2 - diamino - 2 - methylpropane, 2,3-diamino - 2 - methylbutane, 2,4 - diamino - 2 - methylpentane, 2,3 - diamino - 2,3 - dimethyl - butane, m-xylylene diamine, o- and m-phenylene diamines 4,41 - diamino diphenylsulphone, 4,41-diaminodiphenylmethane and 1,3,5-triamino benzene. Fillers specified are aluminium dust, asbestos, glass wool, glass and phenolic microballoons, clays, asphaltine, and thixotropric agents, including highly absorptive materials such as pigments, asbestos floc, silicate clays, micas, colloidal silica, organic complexes of bentonite, attapulgite, metallic soap powders and metallic leafing powders, preferred being quaternary ammonium bentonite complexes, e.g. dimethyl didodecyl ammonium bentonite. From 5 to 45 parts of polyamine, 10 to 70 parts (depending on the alkyl group) of boroxine, 150 parts of aluminium powder filler or 25 parts of microballoons, and up to 30 parts of trichlorofluoromethane, per 100 parts (by weight) of resin can be used.  In Example (1) polyether "A" (a reaction product of bisphenol and epichlorhydrin), 4,41-diaminodiphenyl sulphone, liquid silicone are heated together.  After cooling trimethoxy boroxine (TMB) is stirred in, to bring about a curing and expanding reaction. In other examples, the components used are (3) polyether "A," diethylene triamine and tributoxyboroxine; (4) polyether "A," m-phenylene diamine, aluminium dust and TMB; (5) polyether "A," polyether "D" (a solid polyglycidyl ether of 1,1,2,2-tetrakis (hydroxyphenyl) - ethane, m - phenylenediamine, trichlorofluoromethane, TMB; (6) polyether "A," polyether "B" (from bisphenol A and epichlorhydrin), aniline, m-phenylene diamine, trichlorofluoromethane, TMB; (8) polyether "A," asphalt, m-phenylene diamine and TMB; (9) polyallylglycidyl ether, m-phenylene diamine and TMB; (10) epoxidized novolak resin (a polyglycidyl ether), diaminodiphenyl sulphone, trichlorofluoromethane, TMB; (11) an epoxidized cyclic silicone, diaminodiphenyl sulphone, trichlorofluoromethane and TMB; (12) glycerol/epichlorhydrin adduct, metaphenylene diamine, TMB and in most formulations either silicone oil or trichlorofluoromethane, together with glycerol/propylene oxide adduct (M.W. 1000).  Reference has been directed by the Comptroller to Specification 910,899.