Compositions – Oxidative bleachant – oxidant containing – or generative – Contains organic peroxide
Reexamination Certificate
1999-02-22
2002-07-09
Anthony, Joseph D. (Department: 1714)
Compositions
Oxidative bleachant, oxidant containing, or generative
Contains organic peroxide
C252S186430, C252S186260, C252S186330, C252S187240, C252S187340, C252S186270
Reexamination Certificate
active
06416687
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a bleaching composition which is suitable for laundry applications including hand washing as well as washing with automatic washing machines.
BACKGROUND OF THE INVENTION
Bleach-containing compositions based on hypochlorite bleach or peroxygen bleach are well-known in the art.
However, there are some limitations to the convenience of bleaches. In particular, it is well-known from consumers that the drawbacks associated with the use of bleach-containing compositions especially hypochlorite-based compositions are that said compositions may damage and/or yellow the fabrics which are being bleached.
It is therefore an object of the present invention to provide a bleach-containing composition, suitable for use in laundry application, whereby the fabric whiteness is improved.
It is a further object of the present invention to provide a bleaching composition, suitable for use in laundry application, whereby fabric safety is improved.
Fabrics made of cotton and/or synthetic materials have free hydroxyl groups. It is believed that the fabric damage and/or yellowing that may occur when bleaching a fabric may be due to the oxidation of the hydroxyl groups of the fabric by the bleach. For example, where a liquid hypochlorite-containing composition is applied on the fabric to bleach either in its neat form or in its diluted form, the hypochlorite bleach is present in various forms, including hypochlorous acid, and in the form of free radicals, i.e., molecule fragments having one or more unpaired electrons, such as .Cl, .OH, and/or .ClO. Hypochlorous acid and these free radicals which result essentially from the hypochlorite decomposition pathways are reactive with components having hydroxyl groups such as cotton fabrics or synthetic fabrics, oxidise them and thus contribute to damaging and/or yellowing these fabrics. This phenomenon is emphasised at lower pHs. Indeed, low pHs shift the chemical equilibrium between hypochlorite and hypochlorous acid to the latter, which has been found to contribute to fabric yellowing and fabric damage. Also, it is further believed that at lower pHs these hydroxyl groups are more easily oxidised to form, for example, aldehyde groups which are responsible for the yellowing of the fabric.
Therefore we have now found that it is essential to protect the hydroxyl groups of a fabric from the oxidation they may undergo in the presence of a bleach-containing composition, especially a hypochlorite-containing bleaching composition, in order to improve fabric safety and/or whiteness.
It has been found that the previous objects can be met by formulating a composition comprising a bleach, or a mixture thereof, and a fabric protective system capable of esterifying the hydroxyl groups of a fabric. The compositions of the present invention provide improved fabric whiteness and/or improved fabric safety on fabrics bleached therewith, as compared to the same compositions without the fabric protective system according to the present invention. A particularly preferred fabric protective system of the present invention comprises a boron salt and a catalyst for the esterification of the hydroxyl groups of a fabric by said boron salt.
An advantage of the compositions of the present invention is that said bleaching compositions are suitable for the bleaching of different types of fabrics including natural fabrics, (e.g., fabrics made of cotton, and linen), synthetic fabrics such as those made of polymeric fibres of synthetic origin (e.g., polyamide-lasthane) as well as those made of both natural and synthetic fibres. For example, the bleaching compositions of the present invention based on chlorine bleach such as hypochlorite may be used on synthetic fabrics despite a standing prejudice against using such chlorine bleaches on synthetic fabrics, as evidenced by warnings on labels of commercially available hypochlorite-containing compositions and clothes.
A further advantage of the liquid compositions of the present invention is that said bleaching compositions are suitable for the bleaching of fabrics both when used in diluted conditions, e.g. as a detergent additive, and when used in neat condition, e.g. as a liquid pretreater (spotter).
Bleach-containing compositions like chlorine-containing compositions suitable for bleaching fabrics have been described in the art.
WO 88/05462 discloses a composition for removing stains from fabrics comprising an aqueous solution of trisodium phosphate, sodium hydroxide, sodium hypochlorite and a buffer to maintain a pH of between a bout 10 and 12 such a sodium carbonate, sodium bicarbonate, sodium sesquicarbonate or mixtures thereof. However, no fabric protective system capable of esterifying the hydroxyl groups of a fabric is disclosed, let alone boron salts and a catalyst for the esterification of the hydroxyl groups of a fabric by said boron salts.
EP-A-622 451 discloses compositions comprising hypochloste, sodium hydroxide, a bleach stable perfume and as a buffering system whereby the pH of the diluted composition is buffered to a constant value throughout use, carbonate and/or silicate. However, no fabric protective system capable of esterifying the hydroxyl groups of a fabric is disclosed, let alone boron salts and a catalyst for the esterification of the hydroxyl groups of a fabric by said boron salts.
EP-AU 3 482, EP-AK66 345 and EP-A-688 857 disclose hypochlorite-containing compositions comprising a source of strong alkalinity, a pH buffering means and optionally other types of ingredients such as respectively radical scavengers, polycarboxylate acids of pyridine and periodates. No fabric protective system capable of esterifying the hydroxyl groups o f a fabric is disclosed therein.
UK 1282 906 discloses stabilised aqueous alkali metal hypochlorite solutions comprising as a stabiliser an alkali metal heptonate or boroheptonate. “Alkali metal boroheptonate” as used in UK 1282 906 refers to a mixture of an alkali metal heptonate with either boric acid or an alkali metal metaborate and generally containing two gram moles of alkali metal heptonate per gram atom of boron in the boric acid or metaborate. No laundry application is disclosed. No fabric protective system capable of esterifying the hydroxyl groups of a fabric is disclosed.
BE-749728 discloses an aqueous system comprising an N-hydrogenated compound and a hypohalite such as hypobromite, hypochlorite or hypoiodite in equilibrium with said N-hydrogenated compound, and a buffering system to maintain the pH of said system in a range of 4 to 11 to stabilise it before use. BE-749728 does not disclose a fabric protective system capable of esterifying the hydroxyl groups of a fabric.
U.S. Pat. No. 4,909,956 discloses a bleaching granule which comprises an alkali metal dicloroisocyanurate, a buffering agent and a mitigating agent like sulfamic acid and heterocyclic amides. U.S. Pat. No. 4,909,956 does not disclose a fabric protective system capable of esterifying the hydroxyl groups of a fabric.
SUMMARY OF THE INVENTION
The present invention encompasses a bleaching composition for the bleaching of fabrics, which comprises a bleach, or a mixture thereof, and a fabric protective system capable of esterifying the hydroxyl groups of a fabric. In the preferred embodiment of the present invention the fabric protective system comprises a boron salt and a catalyst for the esterification of the hydroxyl groups of a fabric by said boron salt.
The present invention also encompasses a method of bleaching fabrics wherein said fabrics are contacted with a bleaching composition comprising a bleach, or a mixture thereof, and a fabric protective system capable of esterifying the hydroxyl groups of a fabric.
The present invention further encompasses the use of a catalyst for the esterification of the hydroxyl groups of a fabric by a boron salt, in a bleaching composition comprising a bleach, preferably a chlorine bleach, and a boron salt, to improve the fabric whiteness performance and/or fabric safety of said composition.
DETAILED DESCRIPTION OF THE INVENTIO
Agostini Andrea
Todini Oreste
Anthony Joseph D.
Cook C. Brant
Echler Richard S.
Zerby Kim W.
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