Cleaning compositions for solid surfaces – auxiliary compositions – Cleaning compositions or processes of preparing – With oxygen or halogen containing chemical bleach or oxidant...
Reexamination Certificate
2002-04-17
2003-05-20
Delcotto, Gregory (Department: 1751)
Cleaning compositions for solid surfaces, auxiliary compositions
Cleaning compositions or processes of preparing
With oxygen or halogen containing chemical bleach or oxidant...
C510S302000, C510S303000, C510S307000, C510S309000, C510S310000, C510S311000, C510S370000, C510S376000, C252S186380, C252S186390, C252S186410, C252S187100, C252S186420
Reexamination Certificate
active
06566320
ABSTRACT:
CROSS REFERENCE TO RELATED APPLICATION
This Application claims the benefit of PCT International Application Serial No. PCT/US00/28792, filed Oct. 18, 2000, which claims priority to EP 99870217.9, filed Oct. 19, 1999.
TECHNICAL FIELD
The present invention relates to compositions comprising free radical scavenging compounds based on nitrone derivatives and test methods using such compounds.
BACKGROUND
Free radical scavenging compounds are those which bind, typically harmful free radicals that are generated as by-products of reactions. These compounds are generally known in the art. Examples of commonly used free radical scavengers include butyl hydroxy toluene (BHT), butyl hydroxyanisole (BHA), tertiary butyl hydroquinone (TBHQ), non-tert buty; hydroquinone (MTBHQ), ascorbic acid, propyl gallate. WO97/19054 describes azulenyl nitrone radical scavenging compounds and their uses in medicine as an antioxidant and in the preservation of fuels and foods.
Bleaching compositions comprising either an oxygen-releasing or a hypohalite-releasing bleaching agent can become unstable and loose bleaching power over time. This is possibly due to the reaction of the bleaching agent with heavy metal ions present as impurities in, for example raw materials or water. This reaction results in the decomposition of the bleaching agent and the release of free radicals. By the term free radical it is meant fragments of molecules having one or more unpaired electrons for example Cl, OH and ClO. The free radicals present in bleaching compositions are intensely reactive and it is believed, further catalyse the decomposition of the bleaching agent. The Applicants have found that by inclusion of the free radical scavenger of the present invention in a bleaching composition, the stability of the composition over time is improved. In fact the radical scavenger of the present invention provides parity or improved binding of free radicals versus for radical scavengers currently available in the art, for example butyl hyroxy toluene (BHT).
Furthermore, free radicals are also believed to be detrimental to the integrity of the surface being bleached, for example a fabric. It is believed that the free radicals initiate a reaction of the fabric fibers themselves. An example of which is the oxidation of free hydroxide groups on cotton fibers which contributes to the degradation and premature aging of the fabric. Fabric degradation and premature aging are most often identified by a loss of whiteness of the fabric. Hence it is a further advantage of the present invention that fabric whiteness can be maintained or even improved by washing the fabric with compositions as described herein.
Further still, it has also been found that the radical scavenger compound of the present invention is a useful tool in detecting the presence of free radicals in bleaching compositions. Thus in a further aspect of the present invention is defined a test method for detecting the presence of free radicals.
SUMMARY OF THE INVENTION
According to the present invention there is provided a bleaching composition comprising a bleaching agent and a chromotropic compound having the general formula:
wherein R1 may be hydrogen, a linear or branched alkyl group comprising 1-6 carbon atoms, or an aryl group comprising 6-10 carbon atoms; R2 is a linear or branched alkyl group comprising 1-6 carbon atoms or an aryl group comprising 6-10 carbon atoms; R3 is hydrogen or a linear branched alkyl group comprising 1-6 carbon atoms; R4 may be hydrogen or a linear branched alkyl group comprising 1-6 carbon atoms; R′ is a linear or branched alkyl group comprising 1-6 carbon atoms; W is a linear or branched alkyl group comprising 1-6 carbon atoms, an aryl group comprising 6-10 carbon atoms or an electron withdrawing group; n is 0, 1 or 2, but if n is 2 then each W may be the same or different from one another; m is 0, 1, 2 or 3, but if m is 2 or 3 then each R′ may be the same or different from one another; q is 1 or 2, if q is 2 then each R1 and R2 may be the same or different from one another; p is 0, 1 or 2, if p is 2 each R3 and R4 may be the same or different from one another or a salt thereof.
According to the present invention there is also provided a method of identifying the presence of free radicals released during the decomposition of a bleaching agent using a compound having the above general formula.
In a further aspect of the present invention there is provided a test method using said compound.
DETAILED DESCRIPTION OF THE INVENTION
The present invention relates to a bleaching composition comprising a bleaching agent and a free radical scavenging agent derived from nitrone.
Bleaching Compositions
The present invention also contemplates the free radical scavengers described above as components of a bleaching composition. The beaching composition may comprise any suitable bleaching agent known in the art. Preferred bleaching agents are selected from the group consisting of peroxygen and hypohalite bleaching agents. The bleaching compositions may be in solid or liquid form. By solid form it is meant particulates, for example powder or granular, tablets, blocks, briquettes and the like. By liquid form it is meant conventional liquid compositions and including gels and pastes.
The compositions of the present invention are preferably in liquid form. The liquid compositions herein are preferably aqueous compositions. The liquid compositions according to the present invention preferably have a pH up to 14, more preferably from 1 to 14, and even more preferably from 1.5 to 13.5.
Bleaching Agent
The composition according to the present invention comprise a bleaching agents. The bleaching agent may be selected from any suitable bleaching agent currently available. In a preferred aspect the bleaching agent is selected from either peroxygen bleach and/or hypohalite bleach.
Suitable peroxygen bleaches to be used herein are hydrogen peroxide, water soluble sources thereof, or mixtures thereof. As used herein a hydrogen peroxide source refers to any compound which produces perhydroxyl ions when said compound is in contact with water.
Suitable water-soluble sources of hydrogen peroxide for use herein include percarbonates, persilicates, perborates, peroxyacids such as diperoxydodecandioic acid (DPDA) and pthaloylamido perhexanoic acid (PAP), magnesium perphtalic acid, perlauric acid, perbenzoic and alkylperbenzoic acids, hydroperoxides, aliphatic and aromatic diacyl peroxides, and mixtures thereof. Preferred peroxygen bleaches herein are hydrogen peroxide, hydroperoxide and/or peroxyacids. Hydrogen peroxide is the most preferred peroxygen bleach herein.
Suitable hydroperoxides for use herein are tert-butyl hydroperoxide, cumyl hydroperoxide, 2,4,4-trimethylpentyl-2-hydroperoxide, di-isopropylbenzene-monohydroperoxide, tert-amyl hydroperoxide and 2,5-dimethyl-hexane-2,5-dihydroperoxide. Such hydroperoxides have the advantage to be particularly safe to fabrics and color while delivering excellent bleaching performance.
Suitable aliphatic diacyl peroxides for use herein are dilauroyl peroxide, didecanoyl peroxide, dimyristoyl peroxide, or mixtures thereof. Suitable aromatic diacyl peroxide for use herein is for example benzoyl peroxide. Such diacyl peroxides have the advantage to be particularly safe to fabrics and color while delivering excellent bleaching performance.
Hypohalite bleaches may be provided by a variety of sources, including bleaches that are oxidative bleaches and subsequently lead to the formation of positive halide ions as well as bleaches that are organic based sources of halides such as chloroisocyanurates.
Suitable hypohalite bleaches for use herein include the alkali metal and alkaline earth metal hypochlorites, hypobromites, hypoiodites, chlorinated trisodium phosphate dodecahydrates, potassium and sodium dichloroisocyanurates, potassium and sodium trichlorocyanurates, N-chloroimides, N-chloroamides, N-chloroamines and chlorohydantoins.
For the liquid compositions herein, the preferred hypohalite bleaches among the above described are
Chiaradonna Giusepp
Cicogna Frencesca
Del Duca Valerio
Ingrosso Giovanni
Pinzino Calogero
Delcotto Gregory
McBride James F.
Miller Steve W.
The Procter & Gamble & Company
Zerby Kim W.
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