Cleaning compositions for solid surfaces – auxiliary compositions – Cleaning compositions or processes of preparing – With oxygen or halogen containing chemical bleach or oxidant...
Reexamination Certificate
1999-05-21
2001-06-05
Gupta, Yogendra (Department: 1751)
Cleaning compositions for solid surfaces, auxiliary compositions
Cleaning compositions or processes of preparing
With oxygen or halogen containing chemical bleach or oxidant...
C510S367000, C510S375000, C510S376000, C252S186100, C252S186210, C252S186420
Reexamination Certificate
active
06242407
ABSTRACT:
TECHNICAL FIELD
The present invention relates to the bleaching of soiled fabrics and to compositions suitable to be used as laundry detergent, preferably as laundry pretreater.
BACKGROUND
Peroxygen bleach-containing compositions have been extensively described in laundry applications as laundry detergents, laundry additives or even laundry pretreaters.
Indeed, it is known to use such peroxygen bleach-containing compositions in laundry treatment applications to boost the removal of encrustated stains/soils which are otherwise particularly difficult to remove, such as grease, coffee, tea, grass, mud/clay-containing soils and the like. However, we have found that a drawback associated with such peroxygen bleach-containing compositions is that the compositions may damage fabrics resulting in tensile strength loss and/or color damage, especially when used in a pretreatment application, i.e., when applied directly (neat) onto the fabrics, and left to act onto the fabrics for prolonged periods of time before washing the fabrics.
It is thus an object of the present invention to provide improved fabric safety and/or color safety to fabrics upon bleaching, especially in pretreatment applications where the compositions are left neat into contact with the fabrics for prolonged periods of time before washing.
Indeed, when bleaching fabrics with a composition comprising a peroxygen bleach like hydrogen peroxide, it has been found that the presence of metal ions such as copper and/or iron and/or manganese and/or chromium on the surface of the fabrics and/or the exposure to UV radiation from sunlight of the fabrics after having been contacted with the peroxygen bleach-containing composition, produces fabric damage resulting in loss of tensile strength of the fabric fibres and/or in color damage of the fabrics. Indeed, it is speculated that the presence of metal ions such as copper and/or iron and/or manganese and/or chromium on the surface of the fabrics, especially on cellulosic fibres, and/or the exposure of the fabrics to UV radiation from sunlight catalyse the radical decomposition of peroxygen bleaches like hydrogen peroxide. Thus, it is believed that a radical reaction occurs on the surface of the fabrics with generation of free radicals, which results in tensile strength loss. Furthermore, it is speculated that this generation of free radicals may further provide an aggressive decomposition of certain dyes present in the fabrics resulting thereby in chemical damage of dye molecules which is visible as discoloration and/or hue change. Dyes commonly present in colored fabrics include metal containing dyes like copper-formazan dyes or metal-azo dyes.
It has now been found that improved fabric safety and/or color safety can be achieved by formulating a liquid bleaching composition comprising a peroxygen bleach, propyl gallate and an antioxidant. More particularly, it has been found that the use, in a peroxygen bleach-containing composition for bleaching fabric, of an antioxidant together with propyl gallate, considerably reduces the color damage and/or fabric damage on a fabric bleached with such a composition, especially in a pretreatment application.
An advantage of the present invention is that excellent laundry performance on a broad range of stains and soils such as bleachable stains and/or greasy stains is also provided.
Another advantage of the present invention is that the compositions according to the present invention provide excellent performance when used in any laundry applications, for instance when used as a laundry detergent or a laundry additive, and especially when used as a laundry pretreater, or even in other applications like in hard surface cleaning applications.
Yet another advantage is that the compositions herein are physically and chemically stable upon prolonged periods of storage.
EP-B-209 228 discloses compositions comprising a peroxide source like hydrogen peroxide, metal chelating agents such as amino polyphosphonate chelants and free radical scavengers at a level of from 0.005% to 0.04% by weight of the total composition. No propyl gallate is disclosed.
European patent application number 95870082.5 discloses a peroxygen bleach-containing composition comprising two types of radical scavengers and optionally a chelating agent. No antioxidants are disclosed.
European patent application number 95870079.1 discloses a peroxygen bleach-containing compositions comprising a polyamine, and optionally a chelating agent and a radical scavenger. No antioxidants are disclosed.
In none of these patent applications it is mentioned nor suggested that the use of an antioxidant together with propyl gallate, in a peroxygen bleach-containing composition, reduce the loss of tensile strength in fabrics and/or color damage of said fabrics, when said fabrics are bleached with said composition.
SUMMARY OF THE INVENTION
The present invention encompasses a liquid composition suitable for bleaching fabrics comprising a peroxygen bleach, from 0.001% to 10% by weight of the total composition of propyl gallate, and from 0.001 % to 10% by weight of an antioxidant. In a preferred embodiment the composition further comprises a chelating agent.
The present invention further encompasses processes of bleaching fabrics, starting from a liquid composition as defined herein. The processes include the steps of contacting said fabrics with the liquid bleaching composition neat or diluted, and subsequently rinsing said fabrics. In the preferred embodiment, when the fabrics are “pretreated”, the composition is applied neat on the fabrics, and the fabrics are subsequently washed in a normal wash cycle.
DETAILED DESCRIPTION OF THE INVENTION
The present invention encompasses a liquid composition comprising a peroxygen bleach, from 0.001% to 10% by weight of a propyl gallate and from 0.001% to 10% by weight of an antioxidant.
As an essential element the compositions according to the present invention comprise a peroxygen bleach or a mixture thereof. Indeed, the presence of peroxygen bleach provides excellent bleaching and cleaning benefits. 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, persulphates such as monopersulfate, perborates, peroxyacids such as diperoxydodecandioic acid (DPDA), 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 diacyl peroxide. 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.
Typically, the compositions herein comprise from 0.1% to 20% by weight of the total composition of said peroxygen bleach or mixtures thereof, preferably from 1% to 15% and most preferably from 2% to 10%.
As a second essential element the compositions according to the present invention comprise propyl gallate. Typically, the compositions herein comprise from 0.001% to 10% by weight of the total composition of propyl gallate, preferably from 0.002% to 5%, more preferably from 0.00
Bertacchi Gabriella
Del Duca Valerio
Ricci Carlo
Scaramella Roberto
Echler Sr. Richard S.
Gupta Yogendra
The Procter & Gamble & Company
Webb Gregory
William Zerby Kim
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