PROCESS FOR THE PREPARATION OF PIGMENTARY COMPOSITIONS AND COMPOSITIONS RESULTING THEREFROM

摘要

1482218 Production of coated pigment particles PRODUITS CHIMIQUES UGINE KUHLMANN 20 June 1974 [20 June 1973] 27312/74 Heading C3P The coating of pigmentary particles by the "in situ" polymerization or copolymerization of at least one ethylenically unsaturated monomer having at least one polymerizable double bond and containing at least three carbon atoms, or at least two carbon atoms and a heteroatom and/or a halogen atom attached to one of the carbon atoms, is effected in an organic solvent in which the monomer, catalyst and activator are soluble, but in which the polymer or copolymer formed is insoluble, and the ratio by weight of pigment to polymer or copolymer formed ranges from 10/90 to 95/5, the amount of catalyst being 0À1-10% with respect to the weight of the monomer to be polymerized. Lists of monomers, solvents and catalysts are given. According to Example 1, 278 parts of a #- copper phthalocyanine pressed paste containing 64% of water and 350 parts of heptane are charged into a reactor provided with a condenser and an agitation system. After kneading for several hours, a mixture consisting of 80 parts acrylonitrile, 20 parts methyl methacrylate, 1 part tert.-butyl perpivalate and 1 part tert.- butyl peroctoate is added. The "in situ" copolymerization of the pigment particles is effected by raising the temperature of the polymerizable mixture to 90‹ C. The resulting composition, after removal of the heptane by distillation and drying, consists of 95 parts each of pigment and acrylonitrile-methyl methacrylate copolymer (80-20). The composition is very friable and can be easily converted into a powder. In certain other examples the pigmentary material is a dispersion of powdered #-copper phthalocyanine in methanol, pressed paste of indanthrone, titanium dioxide, specified yellow or green pigments, or yellow iron oxide. The solvent is methanol, heptane or cyclohexane, and the monomer mixtures are: methyl, heptyl, lauryl or stearyl methacrylate with acrylonitrile; methyl methacrylate and acrylic acid; and stearyl and methyl methacrylates with acrylonitrile. Peroxide catalysts and activators are also given. The colouristic development of the pigment compositions produced according to the examples is demonstrated spectrophotometrically by suspending the compositions in specified inks or a dilute solution of acrylonitrilemethyl methacrylate copolymer in dimethyl formamide, and preparing test films of 0À1 mm. thickness from each sample.