Patent GB-675168-A (GB)
Title: Manufacture of epoxide resins
IPC: C08G59/62
Filed: 1947-12-15
Abstract: Process for the production of epoxide resins comprising reacting dihydric phenols and aliphatic polyepoxides in such proportions that there is excess of epoxide groups over and above that required to react with the phenolic hydroxyl groups and the resin obtained has thus free epoxy groups through which the resin may be further polymerized to the infusible state.  Dihydroxy phenols specified are resorcinol, hydroquinone, 1,5-dihydroxy naphthalene, bis phenol (p,p1-dihydroxy diphenyl dimethyl methane), p,p1 - dihydroxy benzophenone, p,p1-dihydroxy diphenyl, p,p1-dihydroxy dibenzyl, bis-(4-hydroxy phenyl) sulphone, 2,21 - dihydroxy - 1,11 - dinaphthyl methane.  There may also be used reaction products of phenols and epoxy compounds containing free phenolic hydroxyl groups, e.g. the reaction product of 2 mols. di-epoxide and 3 mols. dihydric phenol and reaction products of dihydric phenols with dichlorides in the presence of caustic soda and in proportions such that the product will contain free phenolic hydroxyl groups, also the reaction products of dihydric phenols and dibasic acids.  Polyepoxides used for the reaction are open-chain compounds containing two or more epoxide groups, e.g. 1,2-epoxy-3,4-epoxy butane; the epoxy groups may be separated from each other by ether linkages, e.g. as in bis-(2,3-epoxypropyl) ether.  Epoxides derived from mannitol, sorbitol, erythritol or polyallyl alcohol may also be used.  The polyhydric phenols or their complex intermediate compounds and the epoxy compounds may be mixed and used as impregnating &c. compositions, preferably with a trace of catalyst and further polymerized in situ, e.g. bisphenol and bis-(2,3-epoxypropyl) ether in molar proportion of 2 to 3 are mixed with a trace of NaOH as catalyst to form a liquid composition which is used to impregnate fibrous material and polymerized by heating in situ. The polymers are soluble in methyl ethyl ketone, diacetone alcohol and cyclohexane. Examples (1) to (4) illustrate the production of complex dihydric phenols in which the residues of simple dihydric phenols are united through (a) residues from dibasic acids, (b) dihalides.  Example (1), bisphenol is acetylated with acetic anhydride and the product esterified with polymerized soy bean acids; (2) bisphenol is reacted with dibromobutene in presence of caustic soda.  Bisphenol is similarly reacted (3) with b,b1-dichlordiethyl ether; (4) with adipic acid and acetic anhydride.  Examples (5)-(11) illustrate the production of the epoxides resins from dihydric phenols and the poly-epoxides according to the invention.  In examples (5)-(11) diglycidether is reacted with (5) bisphenol, (6) resorcinol, (8) hydroquinone, (10) p,p1-dihydroxy diphenyl sulphone, (9) 4.6 parts bisphenol, 4.3 parts diglycid ether and 0.032 parts NaOH were heated for 45 minutes at 100 DEG  C.  A solution of the product in methyl ethyl ketone containing 1 per cent of the epoxide composition of sodium phenoxide gave films which hardened on heating to 150 DEG  C. for 30 minutes.  It is stated that the epoxide resins of the invention can be reacted with compounds containing active hydrogen, e.g. amines, polyamines, amides, mercaptans, polyhydric alcohols, and (as open to inspection) diisocyanates. Specification 675,171 is referred to.  The Specification as open to inspection under Sect. 91 is not restricted as to the proportions of the reactants employed, nor to dihydric phenols, polyhydroxy naphthalenes and anthracenes and o1,p1-tetrahydroxy diphenyl methyl methane being also specified.  The diepoxides can be produced in a high degree of purity by fractional distillation to separate them from products formed during their manufacture; mixtures may be used without isolation after purification to remove inorganic impurities and catalysts.  The polyepoxides may contain small proportions of monoepoxides which form terminal hydroxyl groups with the phenols. The Specification as open also contains the following examples which have been cancelled: (V) equimolecular proportions of bis-phenol and 1,2-epoxy-3,4-epoxy butane were refluxed for 1 hour at 125 DEG  C. and then heated to 200 DEG  C.  A resin softening at 197 DEG  C. was obtained which was suitable for moulding or in solution in acetone for making films; (XII) 26.4 parts of the product of example (1) were mixed with 3.4 parts diglycid ether; on heating in an oil bath at 130 DEG  C. an infusible leather-like product was obtained.  The mixture may also be dissolved in methyl ethyl ketone and used to form films which bake at 150 DEG  C.; (XIV) 27 parts of the product of example (3) were mixed with 5.55 parts diglycid ether and the mixture heated at 157-179 DEG C.; a methyl ethyl ketone solution of the product with 5 per cent diethylene triamine as hardener, gave a varnish which when spread in thin films and baked for 30 minutes at 150 DEG  C. gave hard flexible films.  This subject-matter does not appear in the Specification as accepted.