Patent GB-749218-A (GB)
Title: Improvements in or relating to the manufacture of polyhydric phenol-aldehyde-epihalohydrin resins
IPC: C08G59/08
Filed: 1954-04-22
Abstract: 1 Mol. of a bis-phenol (i.e. a binuclear phenol with one hydroxyl group having at least one free ortho or para position in each ring, the rings being linked directly or through a nonreactive group, e.g. oxygen, sulphur, carbonyl, alkylene or alkylidene of 1 - 10 carbon atoms) is condensed with 0.25-0.65 mol. of an aromatic or aliphatic aldehyde and the condensate reacted below 155 DEG F. with epihalohydrin or a homologue thereof in the presence of an alkali. The products are hydrophobic epoxy containing resins which may be cured by heating with amines, e.g. ethylene diamine, diethylene triamine, propylenediamine, triethylamine or benzylamine.  The nuclei of the initial phenol may be joined directly or by -O-, -S-, -C(O)-, an alkylene or an alkylidene group, e.g. 4,41 - dihydroxydiphenyl ether, 4,41-dihydroxydiphenyl sulphide, or 4,41-dihydroxydiphenyl dimethylmethane.  The phenolic nuclei may be substituted, e.g. with chlorine.  The aldehyde may contain up to 20 carbon atoms, e.g. formaldehyde, acetaldehyde, propionaldehyde, n- or iso-butyraldehyde, pentaldehyde, hexaldehyde, heptaldehyde, octaldehyde, decaldehyde, octadecaldehyde, 2-ethylhexaldehyde, cyclohexaldehyde, benzaldehyde or b -phenylpropionaldehyde.  The phenolaldehyde condensate contains an average of 2.25 - 8 phenolic groups. Preferably sufficient epihalohydrin is employed to react with all of them.  With water-insoluble reactants a wetting agent may be added.  The phenolaldehyde reaction mixture may be acidic or basic.  Preferably alkaline catalysts are used, the product is diluted, e.g. with a ketone and the epihalohydrin added gradually. Fresh alkali is then added carefully to complete the reaction. The product is then neutralized, e.g. with phosphoric acid, washed and dried by azeotropic distillation, e.g. with methyl ethyl ketone.  All the examples employ 4,41-dihydroxydiphenyldimethyl methane.  In example I it is reacted with n-butyraldehyde, with added stannous chloride followed by caustic alkali.  To the condensate, diluted with methyl isobutyl ketone, epichlorhydrin is added, followed by caustic soda. The product is neutralized, washed, distilled azeotropically to remove water and finally to free it from solvent.  Example II is similar, employing 2-ethylhexaldehyde.  In example III the phenol is condensed with octadecenyl aldehyde in presence of stannous chloride, and the product with epichlorhydrin.  Example IV is similar to example I employing propionaldehyde.  In Example V aqueous formaldehyde is employed and the resin is dissolved in a mixture of methyl isobutyl ketone and n-butanol to facilitate washing.  The resins may be used as clear finishes or with added pigments.  They are also useful as adhesives, potting or moulding compounds.  They may be esterified with drying or semi-drying oil fatty acids.  The esterification is preferably carried out in presence of a solvent at room temperature or up to temperature 250 DEG  F. or higher.  The esters cure with or without baking and may be pigmented.  In an example the resin of example I was esterified with soyabean oil fatty acids at 460 DEG  F. in presence of triphenyl phosphite.  The resin was diluted with mineral spirits.  U.S.A. Specification 2,564,191 is referred to.