| 摘要 |
763,158. Coating compositions. DU PONT DE NEMOURS & CO., E.I. Dec. 13, 1954 [Jan. 6,1954],No. 35969/54. Drawings to Specification. Class 2 (6). A sprayable non-webbing coating composition comprises a polymer of methyl methacrylate of 55,000-105,000 molecular weight and a solvent therefor, the polymer being present in an amount by weight, based on the total weight of polymer and solvent, between a minimum of 10 per cent and a maximum varying with the molecular weight in accordance with a curve based on the following table: the solvent consisting of fractions having boiling ranges and comparative solvencies within the limits set forth in the following table: Polymers of methyl methacrylate specified are homopolymers and copolymers containing at least 95 per cent of methyl methacrylate and not more than 5 per cent of methacrylic acid, short chain alkyl esters of acrylic and methacrylic acids, vinyl acetate, acrylonitrile and styrene. The solvents are produced by mixing together appropriate proportions of acetone, methyl ethyl ketone, di-isobutyl ketone, cyclohexanone, diacetone alcohol, ethyl alcohol, isopropanol, amyl alcohol, cyclohexanol, methyl acetate, ethyl acetate, amyl acetate, ethyl glycol monoethyl ether acetate, butyl lactate, ethylene dichloride, ethylene glycol monobutyl ether, furfural, benzene, benzene substitute, toluene, toluene substitute, xylene, cyclohexane, hexane and aliphatic and aromatic petroleum hydrocarbons. The coating compositions may also contain plasticizers such as dibutyl, dioctyl, diallyl, dicyclohexyl, dibenzyl, butyl benzyl, 2-ethyl hexyl benzyl, di-(methylcyclohexyl) and butyl cyclohexyl phthalates, mixed benzoic and fatty oil acid esters of pentaerythritol, poly(propylene adipate)dibenzoate, diethylene glycol dibenzoate, tetrabutylthiodisuccinate, butyl phthalyl butyl glycolate, acetyl tributyl citrate, dibenzyl sebacate, triphenyl and tricresyl phosphates, toluene ethyl sulphonamide, and the di-2-ethylhexyl ester of hexamethylene diphthalate, and pigments and fillers such as titanium dioxide, carbon black, iron blues, phthalocyanine blues and greens, metal oxides, hydroxides, sulphides, sulphates, silicates and chromates, organic maroons, aluminium flake, bronze powder, pearl essence, talc, barytes, china clay and diatomaceous earth. The coacting compositions may be prepared by first forming a concentrated solution and then diluting to the required concentration. Methyl methacrylate polymers of the required molecular weight may be prepared by solvency techniques to extract a portion within the desired range, or higher molecular weight polymers may be milled strenuously as described in Specification 709,952, or by polymerizing methyl methacrylate under suitable conditions, e.g. in solution in a mixture of toluene and acetone in the presence of benzoyl peroxide or azodiisobutyronitrile as a catalyst. |
