Cleaning compositions for solid surfaces – auxiliary compositions – Cleaning compositions or processes of preparing – For cleaning a specific substrate or removing a specific...
Reexamination Certificate
1998-03-17
2001-07-24
Howard, Jacqueline V. (Department: 1721)
Cleaning compositions for solid surfaces, auxiliary compositions
Cleaning compositions or processes of preparing
For cleaning a specific substrate or removing a specific...
C510S367000, C510S372000, C510S375000, C510S405000, C252S186410, C252S186420
Reexamination Certificate
active
06265366
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to an improved process for carrying out bleaching and/or limescale removal at a surface.
BACKGROUND OF THE INVENTION
The use of oxygen bleaches in compositions for bleaching household surfaces has been known for a long time and many such compositions are available. However a common difficulty in formulating such a composition is to ensure that it remains stable during storage but is sufficiently active on use. This is particularly difficult to achieve in liquid bleaching compositions. Many solutions have been proposed to this problem but most of these require the use of expensive stabilizing components or of complex formulation processes.
One solution has been to formulate liquid peroxygen bleaches at pHs between about 3 and 7 to produce a stable composition, but in practice such compositions do not provide sufficient bleaching power to be useful for many household situations. Attempts have therefore also been made to formulate liquid peroxygen bleach compositions at pHs above this range to improve the bleaching power. However these generally require expensive stabilizing compounds to prevent loss of activity after manufacturing.
The present invention provides a peroxide bleach product which has acceptable stability after manufacture, but which is capable of providing effective bleaching power when used by the consumer.
Commercial products capable of removing limescale from domestic surfaces are well known. Most of these products are based on acids which simply dissolve the limescale. Many surfaces require both limescale removal and bleaching, but no commercially available products are truly capable of both functions.
Furthermore, it would be convenient to the consumer to purchase one product which could be used either for limescale removal or bleaching as required, even when both functions are not required simultaneously.
The present invention provides a product which is capable of carrying out effective bleaching and/or limescale removal at a surface.
SUMMARY AND DETAILED DISCLOSURE OF THE INVENTION
According to the invention, there is provided a process for bleaching and/or providing limescale removal at a surface, comprising applying to that surface an aqueous composition of hydrogen peroxide or an organic peracid, which composition has a pH of 2 or less and comprises a mixture of: a) an aqueous composition comprising hydrogen peroxide or an organic peracid having a pH of greater than 2 but less than 7 (hereinafter component (a)), and b) an acidic composition (hereinafter component (b)), wherein components (a) and (b) are mixed not more than two hours before being applied to the surface requiring bleaching and/or limescale removal.
Compositions suitable for carrying out the invention may be provided in ready-to-use form or, preferably, may be provided as separate components suitable for mixing by the consumer. Where the compositions are suitable for mixing they may be mixed either directly at the surface or remote from the surface before application.
According to a further aspect of the invention, there is provided a process for preparing an aqueous bleaching and/or limescale removing composition having a pH of 2 or less by mixing a) an aqueous composition comprising hydrogen peroxide or an organic peracid having a pH of greater than 2 but less than 7 (hereinafter component (a)), and b) an acidic composition (hereinafter component (b)), wherein components (a) and (b) are mixed not more than two hours before being applied to the surface requiring bleaching and/or limescale removal.
The organic peracids are preferably compounds of the formula
XC(O)OOH
wherein X is H or CH
3
(CH
2
)
n
and n is an integer from 0 to 8, most preferably peracetic acid (n=0), peroxypropionic acid (n=1) or peroxyhexanoic acid (n=4).
By “acidic composition” is meant a composition comprising at least one acid (in liquid or solid form), such that when mixed in suitable proportions with the aqueous composition comprising hydrogen peroxide or an organic peracid the resultant mixture has a pH of 2 or less.
Component (a) preferably comprises hydrogen peroxide or peracetic acid.
Component (b) may be a solid (i.e. granular or powder) acidic composition or, preferably, an aqueous liquid acidic composition.
Where component (b) is an aqueous liquid, it preferably comprises hydrochloric acid, sulphamic acid, tartaric acid, phosphoric acid, oxalic acid, citric acid or salicylic acid; most preferably hydrochloric acid, sulphamic acid, phosphoric acid or citric acid.
Where component (b) is solid, it preferably comprises tartaric acid, phosphoric acid, ascorbic acid, oxalic acid, citric acid or salicylic acid; most preferably phosphoric acid or citric acid.
In accordance with the invention, the two components (a) and (b) may be mixed in any suitable proportions, depending upon their initial concentrations, suitably such that the finally applied mixture comprises 0.01-30% w/w of hydrogen peroxide or an organic peracid. Preferably, the ratio of component (a) to component (b) is from 10:1 to 1:10 most referably from 2:1 to 1:2.
It is preferred that the two components (a) and (b) are mixed no more than 10 minutes before application to the surface requiring bleaching and/or limescale removal.
It is most preferred that the two components (a) and (b) are mixed at the surface requiring bleaching and/or limescale removal, so that the improved bleaching effect may occur immediately.
In this aspect component (a) may be applied to the surface followed by component (b) or vice versa. Alternatively (and preferably) components (a) and (b) are applied to the surface requiring bleaching and/or limescale removal substantially simultaneously.
According to a preferred embodiment of the present invention, the concentration of hydrogen peroxide or organic peracid in the composition immediately after mixing is from 0.01 to 10% w/w. This would mean for example in a 1:1 mix of component (a) to (b) that component (a) prior to the mixing would contain from 0.02 to 20% w/w of hydrogen peroxide or an organic peracid. Where component (a) comprises hydrogen peroxide it is most preferred that the concentration of hydrogen peroxide in the mixture immediately after mixing should be from 1.5 to 5% w/w. For example, if a 1:1 mixture of components (a) and (b) is to be mixed, then component (a) 15 should comprise from 3 to 10% w/w hydrogen peroxide.
The concentration of the acid in component (b) should be chosen such that the pH of the mixture of components (a) and (b) will be 2 or less. Accordingly this will depend upon the acid chosen, the proportion of components (a) and (b) to be mixed, the initial pH of the component (a), and the intended pH of the mixture of components (a) and (b).
The process of the present invention alleviates the need to use further stabilizing components when preparing commercial products.
The compositions suitable for use in the process according to the invention may further include any other conventional additives known to the art. Examples of these include fragrances, surfactants (for example anionic, cationic, nonionic, amphoteric or mixtures thereof), thickeners, dyes, sequesterants, chelating agents, germicides, preservatives, corrosion inhibitors or antioxidants. Most referably the compositions suitable for carrying out the present invention will contain at least one of the following:
an anionic surfactant (e.g. sodium xylene sulphonate),
a nonionic surfactant (e.g. an alkyl alcohol ethoxylate),
a cationic surfactant (e.g. a quaternary ammonium surfactant),
a thickener (e.g. xanthan gum),
a dye,
a fragrance.
The above auxiliary components may be included in the compositions suitable for use in the process of the present invention at concentrations of from 0.01% w/w to 10% w/w. These auxiliary ingredients may be included in either component (a) or component (b) or both if appropriate.
According to a further aspect of the present invention, there is provided the use of an aqueous composition of hydrogen peroxide or an organic peracid, which compo
Fish & Richardson P.C.
Howard Jacqueline V.
Reckitt Benckiser (UK) Limited
Toomer Cephia D.
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