GB977156A - Attachment of detergent material to synthetic sponge - Google Patents

Abstract

<PICT:0977156/C4-C5/1> <PICT:0977156/C4-C5/2> A composite synthetic sponge and detergent tablet comprises a water-impermeable barrier held by one face to the detergent tablet by means of a water-insoluble pressure-sensitive adhesive, the other face being held by means of a water-insoluble pressure-sensitive adhesive to a synthetic sponge. Suitable anionic detergents are soap, alkyl sulphates, fatty acid monoglyceride sulphates, sulphated alkanolamides or fatty alcohol/ethylene oxide condensates, alkyl or alkylarly sulphonates, N-fatty acyl taurides or sarcosides, sulphoacetates, the cations present being potassium or triethanolamine, but preferably sodium; suitable non-ionic detergents are ethylene oxide condensates with fatty acids or with dialkylphenols, ethylene oxide-propylene oxide block copolymers, and fatty esters of sugars or polyglycols. The barrier film may consist of natural or synthetic rubber, polyamide, polyester, polyvinyl chloride, and vinyl chloride-vinylidene chloride copolymers, but poly (ethylene terephthalate) is preferred. Poly-ethylene and -propylene and cellulose acetate and acetate-butyrate may also be used but are not recommended. The adhesive, which should be flexible and resilient, may be a natural or synthetic rubber, silicone elastomer, polyethylene, polyvinyl acetate, polyvinyl butyral, poly (vinyl n-butyl ether), epoxy resin, protein based glue, melamine-, phenol- and urea-formaldehyde resins, and polyamides, but a solution of nitrile rubber is preferred. Suitable sponge material comprises natural or synthetic rubber, polyethylene, polyester, polyvinyl chloride and acetate, but especially polyurethane of the polyester or polyether types. As shown in Fig. 3 a tablet of detergent 33 having sponge material 35 seated in recess 75 and separated from the detergent material by barrier film 37 may be produced (see Fig. 1) by cutting the continuous bar 11 from plodder 13 into bars 19, pressing the bars in rotating spider 21 to produce a depression 75 in one face and passing the pressed bars to unit 39. Meanwhile sponge strip 45 is coated with adhesive through feeder 47, barrier film 51 is superimposed, further adhesive is applied by feeder 53, and a further layer of backing paper 57 then applied. Cutter 59 then cuts through all layers except the paper, and stripper 61 removes unrequired pieces of material before the strip of sponges on the backing sheet pass to unit 39. In this unit the backing 57 is stripped from the sponge laminate and the fresh adhesive face is pressed against recess 75 in the tablets. The composite detergent block and sponge is then further pressed in press 73 and wrapped in 65, the wrapping material and also the cartons in which the wrapped bars are packed also serve to compress the detergent block and sponge together, thereby improving the bond.