Cleaning compositions for solid surfaces – auxiliary compositions – Cleaning compositions or processes of preparing – For cleaning a specific substrate or removing a specific...
Patent
1997-02-28
1999-03-09
Anthony, Joseph D.
Cleaning compositions for solid surfaces, auxiliary compositions
Cleaning compositions or processes of preparing
For cleaning a specific substrate or removing a specific...
25218622, 25218626, 25218627, 25218628, 25218629, C11D 339, C11D 3395, C01B 1501, C01B 1510
Patent
active
058800794
DESCRIPTION:
BRIEF SUMMARY
This application is a 35 U.S.C. 371 application of PCT/US95/06222 filed May 18, 1995.
TECHNICAL FIELD
The present invention relates to bleaching compositions. The compositions of the present invention are particularly useful for laundry bleaching.
BACKGROUND
Compositions for the bleaching of laundry have been extensively described in the art. Bleaching compositions can be classified into peroxide bleaching compositions and hypochlorite bleaching compositions. Peroxide bleaching compositions have the advantage over hypochlorite bleaching compositions that they are generally considered as being somewhat safer to fabrics, specifically to colored fabrics. Peroxide compositions however have the inconveniency that they are often chemically unstable, which makes it difficult to formulate peroxide bleaching compositions which are sufficiently stable to be commercialized. A possible solution to this problem consists in formulating compositions with a high level of peroxide, to extend the "effective" period of the composition. A possible drawback of this solution is that compositions may reach the user which still comprise a high amount of peroxide, whereby possible skin itching may occur if the user's skin comes in contact with the peroxide composition. This itching phenomenon is quite moderate and fully reversible, but is does constitute potential discomfort for the user.
Also, peroxide species are poorly effective in bleaching at lower temperatures, so that it is required to formulate activated peroxide bleaching compositions for use across a wider range of temperatures. Activated bleaching compositions comprise a bleach activator, typically a peracid precursor, which will react in an aqueous medium with hydrogen peroxide to form the corresponding peracid. This peracid is more effective at lower temperatures.
It is thus an object of the present invention to formulate a peroxide bleaching composition which is stable, without having to resort to using higher amounts of peroxide, and which can be activated in a stable manner.
It is also an object of the present invention to formulate a bleaching composition with superior bleaching performance.
In response we have now found that this object can be met by formulating an aqueous emulsion of nonionic surfactants, in which benzoyl peroxide is incorporated. Benzoyl peroxide may constitute the bleaching peroxide specie alone, as it hydrolyzes in aqueous medium in neutral/alkaline pH so as to generate a peracid. But in a preferred embodiment of the present invention, a composition is formulated which comprises hydrogen peroxide in one phase of the emulsion and benzoyl peroxide in the other phase of the emulsion.
Bleaching compositions formulated as emulsions have been disclosed in EP 598 170. The compositions in '170 are emulsions comprising hydrogen peroxide in one phase and a hydrophobic liquid ingredient in the other phase. This hydrophobic liquid ingredient can be a peracid precursor.
SUMMARY OF THE INVENTION
The present invention is an aqueous bleaching composition in the form of an emulsion comprising a hydrophilic nonionic surfactant and a hydrophobic nonionic surfactant, said emulsion further comprising an effective amount of benzoyl peroxide.
DETAILED DESCRIPTION OF THE INVENTION
The compositions according to the present invention are stable aqueous emulsions of nonionic surfactants. By stable emulsion it is meant an emulsion which does not macroscopically separate into distinct layers, upon standing for at least two weeks at 20.degree. C., more preferably at least six months. As used herein, the term emulsion refers to emulsions which are obtained when smaller amounts of benzoyl peroxide are used, so that it is completely soluble in the hydrophobic nonionic surfactant, as well as suspensions which are obtained when the level of Benzoyl peroxide is increased to the point where part of it is not dissolved in the hydrophobic nonionic surfactant, and aggregates of Benzoyl Peroxide are formed in the aqueous phase.
The compositions according to the present i
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Polotti Gianmarco
Scialla Stefano
Scoccianti Raffaele
Anthony Joseph D.
Aylor Robert B.
The Procter & Gamble & Company
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