GB1031831A - Detergent tablets - Google Patents

Abstract

Detergent tablets are coated by applying e.g. spraying, to the surface thereof a mixture of a water-soluble film-forming organic polymer, a colouring material which is dispersible or soluble in water, and an organic surfactant in an aqueous liquid medium, and drying the surface of the tablet to form a coloured solid coating of substantially uniform appearance. The polymer may be polyvinyl alcohol, ethoxylated polyvinyl alcohol, sodium carboxymethyl cellulose, hydroxypropyl methyl cellulose, hydroxyethyl cellulose, or polyvinylpyrrolidone, The colouring matter may be a dye or pigment. those specified being Heliogen Blue WD, Monastral Blue, and Eriocyanine Blue. The surfactant may be an alkyl benzene sulphonate, a dioctyl sulphosuccinate, a monoglyceride sulphate, a soap, or a polyethenoxy ethanol derivative of nonyl phenol. When anionic, the surfactant is usually in the form of an alkali metal, e.g. Na, salt. The liquid medium is preferably water containing a minor amount of glycerol. The tablets to be coated contain anionic or non-ionic detergents and inorganic salts, with or without conventional additives. Suitable anionic detergents are Na and K salts of alkyl benzene sulphonates, alkyl sulphates, fatty acid monoglyceride sulphates, a -sulpho fatty acids, N-methyl taurides, polyethenoxy sulphates, and soaps. Suitable non-ionic detergents are block copolymers of ethylene and propylene oxides, and polyethenoxylated alkyl phenols, alcohols, fatty acids and esters and ethers of sugar alcohols. The inorganic salts include pentasodium tripolyphosphate, tetrasodium pyrophosphate, sodium phosphate and acid phosphates, sodium silicate, sodium carbonate, sodium sulphate, sodium chloride, and corresponding potassium salts. In an example, a detergent tablet also contains cetyl alcohol and talc.ALSO:Detergent tablets are coated by applying e.g. spraying, to the surface thereof a mixture of a water soluble film forming organic polymer, a colouring material dispersible or soluble in water and an organic surface active compound in an aqueous liquid medium and drying the surface of the tablet to form a coloured solid coating of substantially uniform appearance. Preferably the mixture is used at 10 DEG to 90 DEG C. and contains 0.15 to 10.0% by weight of the mixture of an anionic or nonionic synthetic organic detergent, 5 to 30% by weight of a synthetic organic film forming polymer and sufficient colouring matter to noticeably colour the coating applied e.g. 0.001 to 5% by weight. Suitable anionic detergents used are higher alkyl benzene sulphonates higher fatty alcohol sulphates, higher fatty acid monoglyceride sulphates, alpha sulphonated higher fatty acids, higher fatty acid amides of N-methyl taurine, higher fatty acid soaps and sulphated polyethoxy detergents. Preferably sodium tridecyl benzene sulphonate is used in which the alkyl group is derived from a mixture of propylene tetramer and pentamer, the alkyl group having 12 to 15 carbon atoms. Potassium salts are also used. Non-ionic detergents specified are ethoxylated alkyl phenols (IGEPALS), block copolymers of ethylene and propylene oxides (Pluronics) reaction products of higher fatty alcohols and lower alkylene oxides (Emulphogene), polyoxyethylated higher fatty acids (Emulphor); and polyethoxy and poly lower alkoxy esters and ethers of sugar alcohols e.g. sorbitol and mannitol; preferably nonyl phenoxy polyoxyethylene ethanol of 9 to 10 ethoxy groups per molecule or nonionic detergents having C6 to C14 alkyl groups and 4 to 12 ethoxy units each unit having 2 to 4 carbon atoms are used. Polymer materials used include polyvinyl alcohol, ethoxylated polyvinyl alcohol, sodium carboxymethyl cellulose, hydroxypropyl methyl cellulose, hydroxyethyl cellulose and polyvinyl pyrrolidone; the polyvinyl alcohol may contain 15 to 30% of polyvinyl acetate. Colouring matters used are dyes or pigments, the latter having wetting agents incorporated therewith. Specified pigments are phthalocyanines e.g. Heliogen Blue WD or Monastral Blue and Eriocyanine blue dye (Giegy) is used. Preferably the liquid medium is water to which small quantities of glycerol may be added. The tablet to be coated may contain inorganic salts e.g. pentasodium tripolyphosphate, tetrasodium pyrophosphate, sodium phosphate and salts of phosphoric acid, sodium silicate, carbonate, sulphate and chloride. Potassium salts are also used. The tablets are prepared by spray drying on aqueous mixture of synthetic detergent and inorganic salt and compacting at under 100 p.s.i.g. The tablet contains 10 to 40% detergent, 30 to 90% of inorganic salt, the residue being, perfume, moisture, fluorescent brighteners, foaming agents, bactericides and sequestrants. Spraying of the tablets take place at 1000 to 2000 p.s.i.g. at the nozzle tip, the particle size of the sprayed material being 100 to 1000 microns in diameter.