Patent GB-1112062-A (GB)
Title: Coating compositions
IPC: C25D13/06
Filed: 1966-04-21
Abstract: An aqueous electrophoretic coating composition comprises a dispersion of the reaction product of (1) an adduct of a drying oil fatty acid ester and at least one a :b -ethylenically unsaturated dicarboxylic acid or anhydride and (2) a polyol in an amount sufficient to esterify the adduct partially, the product being ungelled.  Suitable oils include tall oil, linseed, soya, safflower, perilla, tung, oiticica, poppy-seed, sunflower, walnut, dehydrated castor, herring, menhaden and sardine oils and such oils modified by reaction with acids, e.g. butyric, stearic, linoleic, phthalic, isophthalic, terephthalic and benzoic acids or polyols, e.g. trimethylolethane, trimethylolpropane, pentaerythritol and sorbitol.  Suitable acids are maleic and itaconic acids or anhydrides.  Ethylenic monomers and resins may be incorporated by reaction with the oil or the adduct (lists given). polyol is preferably a diol, e.g. ethylene, 1:2-propylene, 1:4-butylene and 1:5-pentylene glycols, 2-methyl-2-n-propyl-1:3-propane diol, diethylene and triethylene glycols, poly(oxytetramethylene) glycols, neopentyl glycol, 2:2-bis(4-hydroxycyclohexyl)propane and 1:11-isopropylidene - bis(p - phenyleneoxy)di - 2 - propanol. Higher polyols, e.g. trimethylolpropane, glycerol or pentaerythritol may be used in small amounts or in conjunction with a monohydric alcohol.  The products may be dissolved in water containing a base, e.g. a metal hydroxide or quaternary ammonium hydroxide, ammonia, or any primary, secondary or tertiary amine (lists given), and optionally a pigment may be added, e.g. TiO2, C black, BaSO4, SrCrO4, iron oxides, lead oxides, talc, Cd red and yellow, chrome yellow, toluidine red and phthalocyanine blue, together with, e.g. antioxidants, wetting agents, antifoaming agents, bactericides and suspending agents.  In the examples adducts of maleic anhydride with linseed oil or a linseed oil-hydrocarbon resin adduct or a dehydrated castor oil-linseed oil-hydrocarbon resin adduct are partially esterified with 2:2-bis(4-hydroxy-cyclohexyl)propane, trimethylolpropane, neopentyl glycol, trimethylolpropane monoallyl ether, hexamethylene glycol or the bis-hydroxypropyl ether of bisphenol A.  The products are neutralized with diethylamine and dissolved in water, to which may be added (Example 7) an iron oxide/strontium chromate pigment mixture, to give coating compositions.ALSO:An electrically conductive surface is coated by passing an electric current between the surface and an electrically conductive cathode, the surface and the cathode being in contact with a dispersion in water of the reaction product of (1) an adduct of a drying oil fatty acid ester and at least one #c:b -ethylenically unsaturated dicarboxylic acid or anhydride and (2) a polyol in an amount sufficient to partially esterify the adduct, the product being ungelled.  (See Division C3).  A pigment may also be present, preferably in a ratio of pigment-to-vehicle not greater than 1.5 to 1.  Suitable substrates are iron, steel, aluminium, galvanized steel, phosphatized steel, zinc and copper. Typical voltages for pigmented systems are 50-500 volts.  In examples adducts of maleic anhydride with linseed oil or a linseed oil-hydrocarbon resin reaction product or a dehydrated castor oil - linseed oil - hydrocarbon resin reaction product are partially esterified with2:2-bis (4-hydroxycyclohexyl) propane, trimethylol propane, neopentyl glycol, trimethylol propane monallyl ether, the bis-hydroxypropyl ether of bisphenol A, or hexamethylene glycol.  The products may be dissolved in water containing diethylamine, and, in Example 7, an iron oxide/strontium chromate pigment mixture, and used to coat steel or phosphatized steel panels, the latter 2 ins. apart and using 60-150 volts.  The coating after water-rinsing are baked at 350 DEG F.