GB923069A - Pigments of the quinacridone series and pigmented systems - Google Patents

Abstract

In an example, (9), a red wallpaper colour is made by mixing with a 20% glue solution an aqueous paste containing the precipitate obtained by adding barium chloride solution to a suspension made by suspending heavy spar in aluminium sulphate solution and adding aqueous sodium carbonate and an aqueous paste of the gammamodification of 2:9-dichloroquinacridone.ALSO:Nitrocellulose printing colours, nitrocellulose lacquers, cellulose xanthate spinning compositions, phenoplasts, aminoplasts, polyesters, polyurethanes, polycaprolactams, polyethylene, polystyrene, polyvinyl chloride and polyvinyl acetate are coloured by a pigment which is stated to be the gamma modification of 2:9-dichloroquinacridone. In examples the pigment is mixed with (2) nitrocellulose, dibutyl phthalate, ethyl alcohol and ethyl glycol to give a printing colour, or (3) ester-soluble nitrocellulose, dibutyl phthalate, the synthetic resin obtained by treating cyclohexanone with sodium hydroxide, butyl acetate, methyl acetate and toluene to give a lacquer, and an aqueous paste of the pigment with a sodium 2-naphthalene sulphonate/formaldehyde condensation product is used to colour (8) spinnable alkali cellulose xanthate and (11) dissolved cellulose xanthate containing 8% of a -cellulose. In further examples the pigment is incorporated in (4) a baking lacquer of coconut oil alkyd resin, urea-formaldehyde resin, xylene and butanol, (5) polyvinyl chloride di-isooctyl-phthalate and titanium dioxide and (6) polystyrene, polyethylene or polycaprolactam.ALSO:The invention comprises a pigment which is a modification of 2:9-dichlorquinacridone referred to as the gamma-modification and characterized by an X-ray diffraction pattern having a line of great intensity at a goniometer angle of 27,8 degrees, four lines of medium intensity at 5,4 degrees, 15,3 degrees, 23,0 degrees and 23,4 degrees, and eight lines of low intensity at 16,6 degrees, 19,3 degrees, 21,3 degrees, 24,5 degrees, 25,3 degrees, 26,7 degrees, 29,0 degrees and 30,7 degrees and pigmented systems containing this pigment. When the pigment has an average primary particle size of less than 0,1 micron the X-ray pattern shows an inflection instead of a line at 23,4 degrees. The gamma modification is made by ring-closing 2:5-bis(p-chlorophenyl)- terephthalic acid or an ester thereof in 60-75% sulphuric acid at 140-180 DEG C., by grinding or milling any other modification of 2:9-dichloroquinacridone or by contacting any other modification in finely-divided form with organic solvents such as aliphatic and aromatic mono- and diamines, carboxylic acid amides and their N-alkyl and N-aryl derivatives, sulphonic acid amides, heterocyclic compounds such as imidazole, piperidone, pyrrolidone and its N-alkyl derivatives and quinoline and solvents containing alkali. A large number of solvents are mentioned. Milling to convert the gamma modification into a finely-divided form or to convert other modifications into the gamma modification may be conducted in the dry state in the presence of salts, in water, in acids such as 65-75% sulphuric acid, caustic alkalis such as caustic soda or caustic potash solution, or organic solvents such as aromatic hydrocarbons, halo-hydrocarbons, alcohols, glycols, ethers, carboxylic acid amides, carboxylic acid esters and lactams especially dimethylformamide or N-methylpyrrolidone. A number of solvents are specified. It is stated that the alphamodification of 2:9-dichloroquinacridone is made by ring-closing 2:5-bis-(p-chlorophenyl) terephthalic acid in ten times the amount of 85% sulphuric acid at 150 DEG C., the beta-modification is made by oxidising 2:9-dichlorodihydroquinacridone or by ring-closing 2:5-bis-(p-chlorophenyl)-terephthalic acid with polyphosphoric acid and an unclassified modification is made by precipitating 2:9-dichloroquinacridone from a 5% solution in sulphuric acid by addition of water. Examples are given.ALSO:In an Example (10), a red cement is made by mixing 100 parts of cement, 400 parts of sand, 40 parts of water and 33 parts of an aqueous paste containing a sodium 2-naphthalene sulphonate/formaldehyde condensation product and as pigment the gamma modification of 2 : 9-dichloroquinacridone.