Patent GB-886601-A (GB)
Title: Improvements in or relating to derivatives of pyromellitic acid, their production and their use as curing agents
IPC: C08G59/42
Filed: 1959-12-01
Abstract: Epoxy resins containing more than one epoxide group per molecule, vinyl and acrylic polymers having hydroxyl side groups, polyesters containing terminal or side hydroxyl groups, polyamides having terminal amine groups, diisocyanate prepolymers and urea-, phenol- and melamineformaldehyde condensation products are reacted with a compound of the formula <FORM:0886601/IV (a)/1> where the radical -(O-R-O)- is a divalent organic radical obtainable by removing the alcoholic hydroxyl hydrogen atoms from two alcoholic hydroxyl radicals of an organic polyhydroxy compound (see Group IV(b) ), but which may also be a polymeric radical such as a polypropylene glycol residue (Exx. 3, 6 and 19).  In examples, resin films are obtained from compositions obtained by reacting with a product obtained by reacting pyromellitic dianhydride with 2,2-bis[4-(2-hydroxyethyl)phenyl] propane; a mixture of epoxy resins obtained by reacting epichlorhydrin and bis phenol A (XV); an epoxidized soya bean oil (XVI); an epichlorhydrinbis phenol A resin (XVII); 3,4-epoxy-6-methylcyclohexylmethyl-3,4-epoxy-6-methylcyclohexane -carboxylate (XVII); a poly (allyl glycidyl ether) (XX); a product obtained by reacting a phenolglyoxal resin with epichlorhydrin (XXI); a glycerol-epichlorhydrin reaction product (XXII); 1,3 - bis[3(2, 3 - epoxy - propoxy) propyl] - tetra - methyl disiloxane (XXIII); a mixture of a styreneallyl alcohol copolymer and a product obtained by treating with epichlorhydrin a phenol formaldehyde resin of low molecular weight (XXIV) or a mixture of a melamine-formaldehyde resin and an epoxy resin obtained by reacting epichlorhydrin with 1,4-butane diol (XXV); and a polymeric coating is prepared from a composition obtained by heating a product obtained by reacting a polyoxypropylene glycol with pyromellitic dianhydride, with a -methyl benzyl dimethylamine and a mixture of epoxy resins of the kind employed in Example XV, (XIX).  A trace of a silicone resin levelling agent is added to several of the compositions.  Many conventional solvents are used.ALSO:The invention comprises a compound of the formula <FORM:0886601/IV (b)/1> wherein the radical -(O-R-O)- is a divalent organic radical obtainable by removing the alcoholic hydroxyl hydrogen atoms from two alcoholic hydroxyl radicals of an organic polyhydroxy compound and a process for the preparation thereof wherein pyromellitic anhydride is condensed with an organic polyhydroxy compound containing at least two alcoholic hydroxyl radicals in proportions such that two molecules of the former react with one molecule of the latter.  Di- and polyhydricalcohols specified include 1,4-butanediol, ethylene glycol, neopentyl glycol, diethylene ether glycol, polyoxyethylene- and polyoxypropylene glycol, glycols formed by reacting glycols with ethylene oxide and propylene oxide, cyclic glycols, glycerol, 1,2,6-hexane triol, bis(b -hydroxyethyl) iso- and terephthalates, polyethylene terephthalate, castor oil and sugar.  Substituents which may be present in the polyhydroxy compounds include carboxylic, sulphonate and nitro groups halogen atoms.  Solvents specified include acetone, methylethyl and methyl isobutyl ketones, cyclohexanone, tertiary butyl alcohol, cresyl diphenylphosphate, tris(chlorethyl) phosphate and ethylene glycol monoethyl ether acetate.  In examples, products of the general formula given above are obtained by reacting pyromellitic dianhydride with 2,2-bis[4-(2-hydroxyethyl)phenyl] propane (I); a polyoxyethylene glycol (II); a polyoxypropylene glycol (III); 1,2,6-hexane triol (IV); diethylene glycol and glycerol (V); 2,2-bis(4 hydroxycyclohexyl) propane and ethyl glycol monoethyl ether acetate (VIII); tri-propylene glycol (IX); 2,5-tetrahydrofuran-dimethanol (X); ethylene glycol and ethylene glycol monoethyl ether acetate (XI); 2-butenediol-1,4 (XII); neopentyl alcohol (XIII); bis(2-beta-hydroxyethoxy-5-octylphenyl) methane (XIV); epoxidised soya bean oil (XVI).  Compounds of the kind defined above with reference to the general formula are employed in the preparation of resinous condensation products (see Group IV (a) ).