Patent GB-359643-A (GB)
Title: Improvements in the manufacture and production of colour lakes
IPC: C09B69/04
Filed: 1930-09-09
Abstract: Lakes; urea-formaldehyde condensation products.-Acid dyestuffs are converted into lakes in presence of aqueous solutions of amorphous polymerization products derived from aliphatic polymerizable compounds containing a CO group, viz. water-soluble amorphous polymerization products from the condensation of urea or its derivatives, such as thiourea, with aliphatic aldehydes, e.g. formaldehyde, or from a methylolurea, or neutralized water-soluble amorphous polymerization products (a) of acrylic acid or its homologues, (b) from acrylic acid and styrene, (c) from acrylic acid and vinyl alkyl ethers or vinyl esters, or (d) from maleic acid and styrene.  Organic dispersing agents, such as turkey red oil, inspissated sulphite waste liquor, sulphonic acids of naphthalene or alkylnaphthalenes or resin soaps, and/or water-soluble organic solvents, such as methanol, ethanol, ethylene glycol, or glycerol, may also be present.  Any acid dyestuffs capable of conversion into water-insoluble salts with bases such as calcium, barium, aluminium, or iron may be used, e.g. azo dyes containing one or more carboxyl and/or sulphonic groups and acid triphenylmethane dyes.  The products are distinguished from the lakes obtained without the use of the polymerization products by their smaller covering power, by their freedom from objectionable strong bronze lustre in saturated oil coatings from drying or non-drying vegetable oils or from dispersions in alcohols or cellulose lacquers, and by their valuable strong bluish shades especially when additions such as zinc white are present.  The following examples are specified. (1) An aqueous preparation containing the dyestuff 5-aminotoluene-2 - sulphonic acid --> b  - naphthol, colophony-sodium soap, the sodium salt of polymerized acrylic acid, sodium acetate, and barium chloride is heated to 70 DEG  C. and the product is worked up in the usual manner.  (2) An aqueous preparation containing the dyestuff 4-aminotoluene-3-sulphonic acid --> 2 : 3-oxynaphthoic acid, colophony-sodium soap, calcium chloride, and a condensation product obtained by heating dimethylolurea and formaldehyde in feebly acid solution at 95 DEG  C. and subsequent neutralization with trisodium phosphate, is heated to 80 DEG  C. and the product is worked up in the usual manner.  (3) An aqueous preparation containing Lithol red R, colophony-sodium soap, caustic soda, calcium chloride, and a condensation product obtained by heating urea and formaldehyde in a feebly acid solution at 80 DEG  C. and subsequent neutralization with trisodium phosphate, is heated to 100 DEG  C., and after 2 hours at that temperature the lake is filtered, washed with hot water and dried; the product is a bordeaux red clear modification of the calcium salt of the dyestuff and contains 2 per cent of the salt of the condensation product and 5-15 per cent of calcium rosinate; instead of the above condensation product polymerization products from acrylic acid and styrene, from maleic acid and styrene, from acrylic acid and vinyl ethyl ether, or from saponified acrylic nitrile may be employed.  Polymerized acrylic acid is obtained in the form of its sodium salt by saponifying polymeric acrylic nitrile with 110 per cent of the stoichiometrical quantity of caustic soda in presence of sufficient water to give a 25 per cent solution of the sodium salt at 85-92 DEG  C. and drying the salt.