| 摘要 |
1,243,220. Copolymer coating vehicles. FARBENFABRIKEN BAYER A.G. 25 July, 1968 [7 Sept., 1967], No. 35465/68. Heading B2E. [Also in Division C3] Stoving lacquers contain, as a spontaneously crosslinkable vehicle, a copolymer obtained 'by copolymerising 10-40% by weight of a #- or α-hydroxyalkyl ester of a monoethylenically unsaturated carboxylic acid with 90-60% by weight of one or more monoethylenically unsaturated comonomers, reacting some of the hydroxyl groups of the resultant copolymer with an aromatic dicarboxylic acid anhydride to form the corresponding semi-ester, and then reacting some or all of the remaining hydroxyl groups with an α-alkoxyalkyl isocyanate to form the corresponding urethane. Suitable hydroxy alkyl esters include hydroxyethyl and hydroxypropyl acrylates and methacrylates. Comonomers which may be used include alkyl acrylates and methacrylates, acrylonitrile, methacrylonitrile, styrene, α-methyl styrene, vinyl toluene and vinyl esters of aliphatic carboxylic acids. Aromatic acid anhydrides specified are those of phthalic, tetrabromophthalic, tetrachlorophthalic and Het (registered Trade Mark) acids. Methoxymethyl isocyanate is the preferred alkoxyalkyl isocyanate. The lacquers may optionally containing filler or pigment e.g. titanium dioxide. Suitable solvents for the lacquers include aromatic hydrocarbons, aliphatic ketones and esters, aliphatic or cycloaliphatic alcohols, ethers such as dioxane, ether-esters, and mono-ethers or mono-esters of diols. The lacquers may be applied to substrates 'by methods such as brush coating, spraying, dipping or rolling, and after airdrying are stoved, e.g. at 130‹C. In the Example the lacquer, which includes silicone oil and calcium naphthenate, is sprayed onto glass panels and steel plates. |
