Cleaning compositions for solid surfaces – auxiliary compositions – Cleaning compositions or processes of preparing – With oxygen or halogen containing chemical bleach or oxidant...
Reexamination Certificate
2001-02-28
2003-01-14
Gupta, Yogendra N. (Department: 1751)
Cleaning compositions for solid surfaces, auxiliary compositions
Cleaning compositions or processes of preparing
With oxygen or halogen containing chemical bleach or oxidant...
C510S358000, C510S360000
Reexamination Certificate
active
06506718
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to bleaching compositions, in particular to hypochlorite bleaching compositions, suitable for use in various laundry applications including hand and machine laundry methods.
BACKGROUND OF THE INVENTION
Bleaching compositions are well-known in the art. Amongst the different bleaching compositions available, those relying on bleaching by hypohalite bleaches such as hypochlorite are often preferred, mainly for performance reasons, especially at lower temperature.
However hypohalite bleaches are known to be aggressive bleaching agents that may potentially facilitate the decomposition of other components of a bleaching composition. The Applicant has found that this is particularly true of alkyl ethoxy sulphates which are often preferred anionic surfactants of hypohalite bleach-containing compositions.
EP 243 685 and EP 181 212 both describe compositions comprising alkyl ethoxy sulphate having an average of from 1 to 3 and less than 6 moles of ethoxy groups respectively. However neither document describe compositions comprising hypohalite bleach.
EP 580 245 describes a composition comprising alky ethoxy sulphate having from 1 to 11 moles of ethoxy groups and optionally on oxygen-releasing bleach.
Hence, the object of the present invention is to provide a hypohalite-containing composition comprising an alkyl ethoxy sulphate that is stable and provides improved soil removal benefits.
SUMMARY OF THE INVENTION
The present invention provides a liquid bleaching composition comprising a hypohalite bleach and an alkyl ethoxy sulphate having an average of 2 or less moles of ethoxy groups.
In another aspect of the present invention there is provided the use of said composition to provide improved stain removal and/or fabric whiteness and storage stability.
DETAILED DESCRIPTION OF THE INVENTION
Liquid Bleaching Compositions
The compositions according to the present invention are in liquid form. Preferably, the compositions of the invention are in liquid aqueous form. More preferably, they comprise water in an amount of from 60% to 98% by weight, more preferably of from 80% to 97% and most preferably of from 85% to 97% by weight of the total aqueous liquid bleaching composition.
Hypohalite Bleach
An essential component of the invention is a hypohalite bleach. 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.
The preferred hypohalite bleaches among the above described, are the alkali metal and/or alkaline earth metal hypochlorites selected from the group consisting of sodium, potassium, magnesium, lithium and calcium hypochlorites, and mixtures thereof, more preferably alkali metal sodium hypochlorite.
Preferably, the liquid compositions according to the present invention comprise said hypohalite bleach such that the content of active halide in the composition is from 0.1% to 20% by weight, more preferably from 0.25% to 8% by weight, most preferably from 0.5% to 6% by weight of the composition.
Alkyl Ethoxy Sulphate
The second essential component of the composition of the present invention is an alky ethoxy sulphate. The alkyl ethoxy sulphate is preferably a water-soluble salt or acid of the formula RO(A)
m
SO
3
M wherein R is an unsubstituted C
6
-C
30
linear or branched alkyl group, preferably a C
10
-C
20
linear or branched alkyl, more preferably C
12
-C
18
, most preferably C
12
-C
14
linear or branched alkyl group, A is an ethoxy unit, m is 2 or less, more preferably between 0.05 and 2, most preferably 0.05 to less than 1 mole, and M is H or a cation which can be, for example, a metal cation, preferably an alkali or alkaline earth metal, (e.g., sodium, potassium, lithium, calcium, magnesium, etc.), ammonium or substituted ammonium cation. Specific examples of substituted ammonium cations include methyl-, dimethyl-, trimethyl-ammonium and quaternary ammonium cations, such as tetramethyl-ammonium, dimethyl piperdinium and cations derived from alkanolamines such as ethylamine, diethylamine, triethylamine, mixtures thereof, and the like. Preferred examples of alkyl ethoxy sulphates are selected from the group consisting of C
12
-C
14
ethoxy sulfate. The most preferred alkyl ethoxy sulfate is the sodium salt of lauryl ethoxy (1) sulfate or C
12
H
25
OCH
2
CH
2
OSO
3
Na.
The compositions of the present invention provide improved soil removal fabric whiteness and storage stability versus identical compositions, not comprising an alkyl ethoxy sulfate having 2 or less moles of ethoxy groups.
It is believed that the improved soil removal is achieved due to the higher hydrophobicity of the surfactant and thus the higher affinity for soils. Additionally, the lower the ethoxylation degree, the more weight effective the surfactant, i.e., the higher the molar concentration for a given surfactant level in the finished product. The increased affinity for and subsequent solubilisation and removal of soils is perceived as an improvement in fabric whiteness by consumers.
Furthermore, the compositions of the present invention exhibit improved stability versus identical compositions comprising the alkyl ethoxy sulfate with a higher degree of ethoxylation, i.e. greater than 2. It is believed that this stability benefit is achieved because, as the Applicant has found, it is the ethoxy groups of alkyl ethoxy sulfate that are sensitive to hypohalite bleach. Thus, the Applicant has found that by lowering the number of moles of ethoxy groups of 2 or less, the stability of the surfactant and the composition can be improved without adversely affecting solubility of the surfactant.
Viscosity
Typically such compositions according to the present invention have a viscosity between 0 cps and 2000 cps, preferably between 50 cps and 1100 cps. Has a preferred embodiment of the present invention, the viscosity of the composition can be further modified by addition of a co-surfactant. Where present the ratio of alkyl ethoxy sulfate and a co-surfactant will determine the actual viscosity. Viscosity is measured with a rheometer like carri-med CSL2-100® at the following viscosity parameters angle : 1°58, gap : 60, diameter 4.0 cm, iner: 63.60 at a temperature of 25° C. and a shear rate of 30 1/sec.
Optional components
In addition to the essential components described above, the bleaching composition may also comprise one or more optional components. Optional components may be selected from brightener, radical scavenger, chelating agent, pH buffering agent, co-surfactant and polymers.
Brightener
An optional component of the invention is a brightener. Any brighteners known to those skilled in the art may be used herein including both hydrophobic and hydrophilic brighteners and mixtures thereof.
Brighteners are compounds which have the ability to fluorescence by absorbing ultraviolet wave-lengths of light and re-emitting visible light. Brighteners, also referred to as fluorescent whitening agents (FWA), have been extensively described in the art, see for instance EP-A-0 265 041, EP-A-0 322 564, EP-A-0 317 979 or “Fluorescent whitening agents” by A. K. Sarkar, published by MERROW, especially page 71-72.
Commercial optical brighteners which may be useful in the present invention can be classified into subgroups, which include, but are not necessarily limited to, derivatives of stilbene, pyrazoline, coumarin, carboxylic acid, methinecyanine, dibenzothiophene-5,5-dioxide, azole, 5- and 6-membered-ring heterocycle, and other miscellaneous agents. Examples of such brighteners are disclosed in “The Production and Application of Fluorescent Brigh
Gupta Yogendra N.
McBride James F.
Miller Steven W.
Petruncio John M.
The Procter & Gamble & Company
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