GB995940A - Manufacture of detergent tablets - Google Patents

Abstract

Detergent tablets, in the form of lightly compacted particles which are disintegrable in and soluble in water and are form retaining and resistant to breakage during shipment, comprise by weight 2% to 20% of an anionic and/or nonionic synthetic organic detergent, 20% to 50% of a water-soluble polyphosphate, 20% to 50% of a water-soluble metal silicate and 15% to 35% of water. Specified anionic detergents are: the sodium and potassium salts of C12-C18 alkyl benzene sulphonates; sodium lauryl sulphate, sodium coconut oil fatty acids monoglyceride sulphate and sodium salts of higher fatty acid amide of N-methyltaurine which contain a C10-C18 alkyl or acyl group. Specified nonionic detergents are condensates of C2-C4 alkylene oxides with alkyl phenols containing C6-C14 alkyl groups, each molecule containing 4 to 12 and an average of 9 to 10 alkoxy groups per molecule e.g. nonyl phenol polyoxyethylene ethanol averaging 9.5 oxyalkylene groups. Other nonionics specified are block copolymers of ethylene and propylene oxides, reaction products of higher fatty alcohols and lower alkylene oxides polyethoxy and polyalkoxy esters and ethers of polyalcohols e.g. of sorbitol and mannitol. Specified polyphosphates are pentasodium tripolyphosphate and tetrasodium pyrophosphate. Specified water soluble silicates used are alkali metal salts having a metal oxide to silica ratio, by weight, of 0.3 to 1.0. Other ingredients include potassium hydroxide, sodium and potassium sulphates, sodium carboxy methyl cellulose, colouring agents, fluorescent dyes, perfumes, bleaches, solvents and anti-redeposition agents. The detergent tablets may be made by (1) mixing the components of the tablet, moving and circulating the moistened detergent particles and finally compacting at pressures of 3 to 25 p.s.i. (2) Adding only a portion of the water to the other constituents, spray drying to produce particulate material, adding water to bring the water content up to the required level and finally pressing into tablet form as in (1). The detergent particles may also be prepared by spray cooling, agglomeration and crushing followed by screening and classification of particle size. The final product may be coated with moisture, sodium carboxy methyl cellulose or polyvinyl alcohol.