Cleaning compositions for solid surfaces – auxiliary compositions – Cleaning compositions or processes of preparing – For cleaning a specific substrate or removing a specific...
Reexamination Certificate
2000-06-19
2002-12-17
Gupta, Yogendra N (Department: 1751)
Cleaning compositions for solid surfaces, auxiliary compositions
Cleaning compositions or processes of preparing
For cleaning a specific substrate or removing a specific...
C510S372000, C510S284000
Reexamination Certificate
active
06495501
ABSTRACT:
TECHNICAL FIELD
The present invention relates to the bleaching of soiled fabrics and to compositions suitable to be used as laundry detergent and especially 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 liquid peroxygen bleach-containing compositions having an acidic to neutral pH (typically up to 7, preferably from 1 to 6, and more preferably around 5) 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 these compositions may damage fabric colors, 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 rinsing the fabrics, or before washing the fabrics and subsequently rinsing them.
It is thus an object of the present invention to provide improved 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 rinsing them or washing them and subsequently rinsing them.
Indeed, when pretreating a fabric with a composition comprising a peroxygen bleach like hydrogen peroxide formulated at a pH up to 7, the composition applied neat on the fabric and left to act on it before being rinsed off has the tendency to evaporate on the fabric. It has been observed that upon evaporation of such peroxygen bleach-containing compositions the water contained in such compositions evaporates faster than the peroxygen bleach. In other words, the water evaporation contributes to increase the concentration of peroxygen bleach in the liquid composition that has been poured onto the surface of the fabric. This much higher concentration accelerates the production of free radicals and, as a consequence, the damage of the fabric and of its colours. It is also speculated that an auto-oxidation reaction occurs upon evaporation of water when the liquid compositions are left to dry onto the fabrics. This reaction of auto-oxidation generates peroxy-radicals which may contribute to the degradation of cellulose and of certain dyes present in the fabrics resulting thereby in chemical damage of dye molecules which is visible as discoloration and/or hue change. Thus, it is highly recommended in usage instructions of such commercially available peroxygen bleach-containing compositions to not leave the liquid bleaching compositions to dry onto the fabrics, in a process of pretreating soiled fabrics therewith.
More surprisingly, it has now been observed that this evaporation process also results in a pH drop on top of an increase in bleaching agent concentration. It is speculated that the pH drop to strong acidic values, typically below pH 2, accelerates the color damage when pretreating a coloured fabric.
It has now been found that improved color safety can be achieved by formulating a liquid bleaching composition having a pH up to 7 and comprising a peroxygen bleach, from 0.1% to 10% by weight of the total composition of a pH buffering means and from 0.0001% to 5% by weight of a perfume. More particularly, it has been found that the use, in a peroxygen bleach-containing composition having a pH up to 7, of a pH buffering means, for pretreating a soiled coloured fabric, considerably reduces the color damage on the fabric pretreated with such a composition.
Avantageously, the compositions according to the present invention also provides effective fabric safety on top of the effective color safety.
Another advantage of the present invention is that excellent bleaching 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 not only when used in a pretreatment laundry application but also when used in any laundry applications, for instance when used as a laundry detergent or a laundry additive, 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.
In a preferred embodiment, the compositions according to the present invention further comprise a surfactant or a mixture thereof, for example a zwitterionic betaine surfactant together with an alkoxylated nonionic surfactant. Indeed, it has been found that such a surfactant system further boosts the bleaching performance and contributes to effective stain removal performance on various types of stains including greasy stains like mayonnaise, vegetable oil, sebum, make-up, and the like of the compositions herein. In a highly preferred embodiment herein the compositions of the present invention comprise a salt free zwitterionic betaine surfactant. Indeed, using such salt free zwitterionic betaine surfactants instead of conventional zwitterionic betaine surfactants further contributes to the benefits of the present compositions, i.e., improved color and fabric safety.
SUMMARY OF THE INVENTION
The present invention encompasses a liquid composition suitable for pretreating fabrics having a pH up to 7 and comprising a peroxygen bleach, from 0.1% to 10% by weight of the total composition of a pH buffering means, and from 0.0001% to 5% by weight of a perfume.
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 rinsed, or washed in a normal wash cycle and subsequently rinsed with water.
DETAILED DESCRIPTION OF THE INVENTION
The Liquid Compositions
The compositions according to the present invention are liquid compositions as opposed to a solid or a gas. As used herein “liquid” includes “pasty” compositions. The liquid compositions herein are preferably aqueous compositions. The liquid compositions according to the present invention preferably have a pH up to 7, more preferably from 1 to 6, and even more preferably from 1.5 to 5.5. Formulating the compositions according to the present invention in the acidic pH range contributes to the chemical stability of the compositions and to the stain removal performance of the compositions.
Peroxygen Bleach
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, 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-di
Del Duca Valerio
Giunti Stefano
Scaramella Roberto
Echler Sr. Richard S.
Gupta Yogendra N
McBride James F.
Petruncio John M
The Procter & Gamble & Company
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