GB1463478A - Method of coating polyesters - Google Patents

Abstract

1463478 Cationic polyamide composition FUJI PHOTO FILM CO Ltd 23 June 1975 [28 June 1974] 26616/75 Heading C3R [Also in Divisions B2 and G2] A polyester body, such as a film for use as a photographic support, is coated by applying to at least one of its surfaces an aqueous solution of a polyamide-epichlorohydrin resin and a water-soluble swelling agent for the polyester. The polyester body may be a polyester of at least one dibasic carboxylic acid (e.g. terephthalic, isophthalic, diphenylsulphone-dicarboxylic, diphenoxyethanedicarboxylic, 5 - sodium sulphoisophthalic, diphenylenedicarboxylic, 2,6- naphthalenedicarboxylic, adipic, sebacic and azelaic acids), and at least one polyhydroxy compound such as a glycol and/or a hydroxy acid (e.g. ethylene glycol, propylene glycol, butanediol, neopentylene glycol, 1,4- cyclohexanediol, 1,4 - cyclohexanedimethanol, 1,4 - bis - hydroxyethoxybenzene, diethylene glycol, polyethylene glycol, bisphenols, and p - # - hydroxyethoxybenzoic acid). Preferred polyesters are polyethylene terephthalate, polybutylene terephthalate and polyethylene naphthalate. The polyester body may have only a surface of polyester or may consist entirely of polyester, e.g. as a film, in which case it may be coated according to the invention on one or both surfaces. The polyamide-epichlorohydrin resin may be the product of a reaction of (a) a polyamide produced by reacting a saturated or unsaturated dicarboxylic acid with a polyalkylene-polyamine, with (b) epichlorohydrin. Dicarboxylic acids may be succinic, glutaric, adipic, pimelic, suberic, azelaic, sebacic, itaconic, fumaric, maleic, citraconic and mesaconic acids. Polyalkylene-polyamines may be diethylenetriamine, triethylene tetramine, tetraethylene pentamine and dipropylenetriamine. Usually the proportions of (a) and (b) above are 1 mole of epichlorohydrin per 1-3 moles of amine group in the polyamide. Examples are given for preparing aqueous resin compositions of epichlorohydrin reaction products with two different diethylenetriamine-adipic acid polyamides, and with a tetraethylenepentamine-adipic acid polyamide. Swelling agents used in the coating include polyhydroxyaromatic compounds such as resorcinol, chlororesorcinol, 4-methylresorcinol, 2-methylresorcinol, catechol, pyrogallol, orcinol, phloroglucinol, hydroquinone, and dihydroxynaphthalene, and also pyrrole, chloral hydrate and highly acidic organic acids such as mono- and tri-chloroacetic acid and trifluoroacetic acid. The aqueous coating composition may also contain a surface active agent, e.g. saponin, glycerine esters or sorbitan esters, or sodium dodecylbenzene sulphonate, or polyethylene glycol, and materials such as dyes, polymer latex and matting agents. The coatings may be applied by dip coating, roller coating, curtain coating or extrusion coating, if desired applying more than one coating. Reference has been directed by the Comptroller to Specification 1,379,066.