Cleaning compositions for solid surfaces – auxiliary compositions – Cleaning compositions or processes of preparing – For cleaning a specific substrate or removing a specific...
Reexamination Certificate
2002-04-01
2003-11-25
Delcotto, Gregory (Department: 1751)
Cleaning compositions for solid surfaces, auxiliary compositions
Cleaning compositions or processes of preparing
For cleaning a specific substrate or removing a specific...
C510S303000, C510S340000, C510S372000, C510S376000, C510S500000, C008S111000
Reexamination Certificate
active
06653271
ABSTRACT:
FIELD OF INVENTION
This invention relates to compositions and methods for catalytically bleaching substrates with atmospheric oxygen, using a metal-ligand complex as catalyst, which compositions are formulated as liquids. This invention also relates to a method of treating textiles, such as laundry fabrics, using a metal-ligand complex as catalyst whereby bleaching with atmospheric oxygen is catalysed after the treatment, wherein the treatment composition is formulated as a liquid.
BACKGROUND OF INVENTION
Peroxygen bleaches are well known for their ability to remove stains from substrates. Traditionally, the substrate is subjected to hydrogen peroxide, or to substances which can generate hydroperoxyl radicals, such as inorganic or organic peroxides. Generally, these systems must be activated. One method of activation is to employ wash temperatures of 60° C. or higher. However, these high temperatures often lead to inefficient cleaning, and can also cause premature damage to the substrate.
A preferred approach to generating hydroperoxyl bleach species is the use of inorganic peroxides coupled with organic precursor compounds. These systems are employed for many commercial laundry powders. For example, various European systems are based on tetraacetyl ethylenediamine (TAED) as the organic precursor coupled with sodium perborate or sodium percarbonate, whereas in the United States laundry bleach products are typically based on sodium nonanoyloxybenzenesulphonate (SNOBS) as the organic precursor coupled with sodium perborate.
Precursor systems are generally effective but still exhibit several disadvantages. For example, organic precursors are moderately sophisticated molecules requiring multi-step manufacturing processes resulting in high capital costs. Also, precursor systems have large formulation space requirements so that a significant proportion of a laundry powder must be devoted to the bleach components, leaving less room for other active ingredients and complicating the development of concentrated powders. Moreover, precursor systems do not bleach very efficiently in countries where consumers have wash habits entailing low dosage, short wash times, cold temperatures and low wash liquor to substrate ratios.
Alternatively, or additionally, hydrogen peroxide and peroxy systems can be activated by bleach catalysts, such as by complexes of iron and the ligand N4Py (i.e. N,N-bis(pyridin-2-yl-methyl)-bis(pyridin-2-yl)methylamine) disclosed in WO95/34628, or the ligand Tpen (i.e. N,N,N′,N′-tetra(pyridin-2-yl-methyl)ethylenediamine) disclosed in WO97/48787. These publications do not foresee a role in providing storage stable liquid bleaching compositions even if, according to these publications, molecular oxygen may be used as the oxidant as an alternative to peroxide generating systems.
As discussed by N. J. Milne in J. of Surfactants and Detergents, Vol 1, no 2, 253-261 (1998), it has long been thought desirable to be able to use atmospheric oxygen (air) as the source for a bleaching species. The use of atmospheric oxygen (air) as the source for a bleaching species would avoid the need for costly hydroperoxyl generating systems. Unfortunately, air as such is kinetically inert towards bleaching substrates and exhibits no bleaching ability. Recently some progress has been made in this area. For example, Wo 97/38074 reports the use of air for oxidising stains on fabrics by bubbling air through an aqueous solution containing an aldehyde and a radical initiator. A broad range of aliphatic, aromatic and heterocyclic aldehydes is reported to be useful, particularly para-substituted aldehydes such as 4-methyl-, 4-ethyl- and 4-isopropyl benzaldehyde, whereas the range of initiators disclosed includes N-hydroxysuccinimide, various peroxides and transition metal coordination complexes.
However, although this system employs molecular oxygen from the air, the aldehyde component and radical initiators such as peroxides are consumed during the bleaching process. These components must therefore be included in the composition in relatively high amounts so as not to become depleted before completion of the bleaching process in the wash cycle. Moreover, the spent components represent a waste of resources as they can no longer participate in the bleaching process.
Accordingly, it would be desirable to be able to provide a bleaching system based on atmospheric oxygen or air that does not rely primarily on hydrogen peroxide or a hydroperoxyl generating system, and that does not require the presence of organic components such as aldehydes that are consumed in the process. Moreover, it would be desirable to provide such a bleaching system that is effective in aqueous medium.
It may also be noted that the known art teaches a bleaching effect only as long as the substrate is being subjected to the bleaching treatment. Thus, there is no expectation that hydrogen peroxide or peroxy bleach systems could continue to provide a bleaching effect on a treated substrate, such as a laundry fabric after washing and drying, since the bleaching species themselves or any activators necessary for the bleaching systems would be assumed to be removed from the substrate, or consumed or deactivated, on completing the wash cycle and drying.
It would be therefore also be desirable to be able to treat a textile such that, after the treatment is completed, a bleaching effect is observed on the textile. Furthermore, it would be desirable to be able to provide a bleach treatment for textiles such as laundry fabrics whereby residual bleaching occurs in the presence of air when the treated fabric has been treated and is dry. It would be desirable for the residual bleaching of dry textiles to be conducted irrespective of exposure to light.
A further disadvantage associated with conventional bleaching compositions based on hydrogen peroxide or peroxy systems such those containing organic peroxyacids is that the compositions tend to be chemically or physically unstable in the presence of liquid solvents, carriers or other liquid components such as surfactants, particularly when formulated as aqueous compositions. Consequently, when formulated as liquids, these bleaching compositions on the one hand do not exhibit satisfactory storage stability, resulting in a rapid loss of bleaching activity or in a loss of structural integrity, for example phase separation, or require the incorporation of additional stabilising systems to minimise these effects with attendant disadvantages in terms of cost or processing. Decomposition of a hydrogen peroxide or peroxy liquid bleaching composition in a sealed container leads to an increase in the internal pressure of the sealed container. The increase in the internal pressure leads to the possibility of the sealed container rupturing in a dangerous manner. In the presence of surfactants, decomposition of the hydrogen peroxide or peroxy liquid bleaching composition leads to foaming of the composition. On the other hand, liquid bleaching compositions are conveniently dosed into containers for storage or for use, or otherwise handled, and are desired by the consumer, particularly in the United States of America.
It would therefore also be desirable to be able to provide a bleaching composition in the form of a liquid, which is chemically and physically stable, without at least some of the disadvantages hitherto associated with liquid bleaching compositions. It would furthermore be desirable to be able to provide chemically and physically storage stable detergent bleaching compositions or rinse conditioning bleach compositions in the form of a liquid. Application WO00/29537, filed Nov. 9, 1999, was published after the filing date of the present application disclosing theoretical examples of compositions for bleaching with a transition metal complex in the absence of an added peroxygen bleach. Application WO00/29537 has no evidence of efficacy and includes two classes of ligands: some cross-bridged macrocyclic ligands and some macrocyclic ligands. The macrocyclic ligands are disclosed as mangan
Hage Ronald
Veerman Simon Marinus
Delcotto Gregory
Honig Milton L.
Unilever Home & Personal Care USA , division of Conopco, Inc.
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