Patent GB-934782-A (GB)
Title: Polyester resins
IPC: C08G63/127
Filed: 1959-09-11
Abstract: Polyester resins are prepared by reacting under usual polyester-forming conditions at 100 DEG -240 DEG C., 1 mol. of a benzene tricarboxylic acid or anhydride thereof with 0,6-1,5 mol. of an alkylene glycol for a time just short of the abrupt viscosity increase point.  In a modification, the reaction mixture also includes a dicarboxylic acid, and reaction is at 150 DEG -200 DEG C. until the Acid Number is commensurate with avoiding gelation of the product.  In this case the mole ratio of tricarboxylic acid:dicarboxylic acid:glycol varies from 1:1:2 to 10:1:25.  In either case, 1 mol. of a monohydric alcohol may be included in the reaction mixture for every 1 to 5 mols. of glycol.  Water-soluble resins are produced by treating any of the polyester resins with sufficient alkaline reacting material. Suitable tri-carboxylic acid bodies are trimellitic, trimesic or hemimellitic acid or anhydride. Some suitable glycols mentioned are ethylene or propylene glycol, polymethylene glycols containing from 3 to 11 carbon atoms; 1,3-or 2,3-butanediol; 2,4-pentanediol; 2,5-hexanediol; some methyl and ethyl derivatives of these diols; di-, tri- and tetra-ethylene glycol, di- and tri-propylene glycol. Preferred dicarboxylic acids are alkane dioic acids containing 4-20 carbon atoms.  Suitable monohydric alcohol modifiers are methyl, butyl, hexyl, stearyl, allyl and oleyl alcohol.  Mixtures of oxo alcohols are also suitable.  The products range from viscous liquids to hard solids.  They are soluble in alcohols or ketones or mixtures of them with benzene hydrocarbons. They form hard products on baking, and are suitable binders, e.g. for fibreglass or in making laminates, or as film-formers, if desired with pigments.  The polyesters may be used with amino resins, e.g. melamine- or urea-formaldehyde resins as modifiers.  Suitable alkaline materials for partial or complete neutralization of the polyesters to produce water solubility are ammonia, alkali metal hydroxides, amines, e.g. ethyl- or butylamine, pyridine, morpholine, piperidine.  The polyesters are produced by conventional methods preferably in an inert atmosphere, with removal of water by an azeotroping agent.  In examples polyesters are prepared from (1) and (2) trimellitic anhydride and ethylene glycol, (3) trimesic acid and triethylene glycol, (4) trimesic acid and 1,4-butanediol, (5) trimellitic anhydride and ethylene glycol.  The product was dissolved in ammonia.  (6) Trimellitic anhydride, neopentyl glycol and isooctyl alcohol.  The product was rendered water-soluble by reaction with 2-amino-2-methyl-1-propanol.  (7) Trimellitic anhydride, diethylene glycol and iso-octyl alcohol.  The product was neutralized with tris hydroxymethyl aminomethane.  (8) Trimellitic anhydride and neopentyl glycol.  The products were neutralized with triethanolamine.  (9) Trimellitic anhydride, adipic acid and 1,3-butylene glycol.  The product was dissolved in xylene-butanol, mixed with melamine-formaldehyde resin and formed into baked films. Alternatively it was dissolved in ammonia, and an aqueous solution of the neutralized resin was used with rutile TiO2 to form an enamel. (10) Trimellitic anhydride, adipic acid and propylene glycol.  (11) Trimellitic anhydride, adipic acid and neopentyl glycol.  (12) Trimellitic anhydride, adipic acid and 1,3-butylene glycol. Specification 897,525 is referred to.