Cleaning compositions and their use

Abstract

A cleaning composition contains the components for a pH step reaction, held apart or in stasis in needed, until they are delivered to the locus to be cleaned. The composition may include standard cleaning agents such as surfactants. The composition undergoes a change in pH at the locus, promoting effective cleaning.

1 . A cleaning composition which comprises reactants which undergo a chemical reaction after exposure to a locus to be cleaned, the reaction being such as to produce a delayed change of pH at that locus.  
     
     
         2 . A composition as claimed in  claim 1 , having the property that after exposure to the locus the composition produces a delayed change of pH at that locus of at least 2 pH units.  
     
     
         3 . A composition as claimed in  claim 1  or  2 , having the property that after exposure to the locus the composition produces a delayed increase in pH at that locus.  
     
     
         4 . A composition as claimed in  claim 3 , having the property that on exposure of the composition to the locus the locus is initially acidic and that after an interval the locus is alkaline.  
     
     
         5 . A composition as claimed in claims  3  or  4 , wherein the composition comprises hydrogen peroxide or a precursor of hydrogen peroxide and a multidentate complex of Fe (II) or Co (II) ions.  
     
     
         6 . A composition as claimed in  claim 1  or  2 , having the property that after exposure to the locus it produces a delayed decrease in pH at that locus.  
     
     
         7 . A composition as claimed in  claim 6 , wherein the composition comprises an oxidant selected from a peroxy compound and an oxidising metal compound stable in alkaline solutions; and a reductant selected from an oxyanion of sulfur that contains S—S bonds, and a compound substantially more basic than its oxidised counterpart.  
     
     
         8 . A composition as claimed in  claim 7 , wherein the oxidant is selected from the species BrO 3   − , IO 3   − , ClO 3   − , ClO 2   − , S 2 O 8   2− , ClO 2 , [Fe(CN) 6 ] 3−  and H 2 O 2  or a precursor thereto, and the reductant is selected from the species S 2 O 3   2− , S 4 O 6   2− , S 2 O 4   2− , S 2 O 6   2− , SO 3   2−  and N 2 H 5   + , the oxidant and the reductant together participating in reactions producing pH oscillations.  
     
     
         9 . A composition as claimed in any preceding claim, wherein the composition produces an antimicrobial effect at the locus.  
     
     
         10 . A composition as claimed in any preceding claim, wherein the composition produces a bleaching effect at the locus.  
     
     
         11 . A composition as claimed in any preceding claim, wherein a temperature rise is generated by the reactants at the locus.  
     
     
         12 . A composition as claimed in any preceding claim, the composition being such that the pH change is evidenced by a change in colour or fragrance, or by effervescence.  
     
     
         13 . A composition as claimed in any preceding claim, comprising a surfactant.  
     
     
         14 . A composition as claimed in any preceding claim, wherein the composition is packaged with exclusion of oxygen and/or water and/or carbon dioxide and/or light, as required to prevent a pH change prior to exposure to the locus.  
     
     
         15 . A tablet or sachet, comprising a cleaning composition as claimed in any preceding claim, in liquid, powder or gel form.  
     
     
         16 . A cleaning cloth or sponge, impregnated with a cleaning composition as claimed in any of  claims 1  to  14 .  
     
     
         17 . A lavatory cleaning product to be hung or otherwise located in a cistern or beneath the rim of a lavatory bowl and comprising a composition as claimed in any of  claims 1  to  14 , the product being such that the composition is released progressively with flush water.  
     
     
         18 . A dispensing package containing a cleaning composition as claimed in any preceding claim, wherein the package emits the cleaning composition progressively, as a spray, gel or mousse.  
     
     
         19 . A method of cleaning comprising the application of a cleaning composition as claimed in any of  claims 1  to  14 , to a locus requiring cleaning.  
     
     
         20 . A cleaning composition or product or package, or a cleaning method, in each case substantially as hereinbefore described with particular reference to the accompanying examples.