Cleaning compositions for solid surfaces – auxiliary compositions – With oxygen – halogen – sulfur – or nitrogen containing or...
Reexamination Certificate
2001-03-29
2003-05-13
Hardee, John (Department: 1751)
Cleaning compositions for solid surfaces, auxiliary compositions
With oxygen, halogen, sulfur, or nitrogen containing or...
C510S470000, C510S473000
Reexamination Certificate
active
06562771
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a method of improving perfume deposition onto fabrics during a laundry process and/or retention of perfume on laundered fabrics.
BACKGROUND OF THE INVENTION
During the laundering procedure the consumer frequently requires the laundry to be lightly perfumed. This can occur either by use of a rinse conditioner or during the wash cycle.
Due to the expense of including perfume in a composition it is desirable if the maximum level of perfume possible is deposited onto the laundry and the minimum level of perfume possible is thrown away with the washing solution.
However, much of the perfume used in laundry formulations is wasted. Loss of perfume arises from three main causes:
(a) evaporation during processing,
(b) reaction with other product components (for example alkaline components), and
(c) solubilisation by surfactants during washing.
As a result of these losses, only about 1% of the perfume added at the start of the wash can be recovered from the dry fabric.
The present inventors have now discovered that certain fabric rebuild agents which undergo a chemical change during a laundry process whereby their affinity for fabric is increased can improve deposition of perfume onto fabric.
There is a further problem in that it is desired that the perfume on the fabric should be detectable for as long as possible after laundering. However, there is a natural tendency for the intensity of the perfume to decrease with time, due to evaporation. It is desirable to give a smoother perfume intensity profile over time.
The inventors have discovered that, surprisingly, the fabric rebuild agents can improve the retention of perfume over time on laundered fabrics.
Compositions containing the fabric rebuild agents studied by the inventors are themselves the subject of our copending patent application no. WO 00/18860. The perfume effect of the compositions during laundry treatment processes is not studied in this patent application.
WO-A-99/14245 discloses laundry detergent compositions containing cellulosic based polymers to provide appearance and integrity benefits to fabrics. These polymers are cellulosic polymers in which the saccharide rings have pendant oxygen atoms to which substituents ‘R’ are bonded, i.e. they are attached to the rings via an ether linkage. The groups ‘R’ can be hydrogen, lower alkyl or alkylene linkages terminated by carboxylic acid, ester or amide groups. Optionally, up to five alkyleneoxy groups may be interspersed between the groups are the respective oxygen atom. At least some of these groups may undergo a chemical change such as hydrolysis, in the wash liquor. However no such change would result in an increased affinity for the fabric. On the contrary, because the “ester” group is configured with the carbonyl group closer to the polysaccharide than the oxygen atom (i.e. esters of carboxyalkyl groups), any hydrolysis will result in free acid substituents which will actually result in an increase in solubility and therefore, a decrease in affinity for the fabric.
WO-A-99/14295 discloses structures analogous to those described in WO-A-99/14245 but in one alternative, the substituents ‘R’ together with the oxygen on the saccharide ring, constitute pendant half-esters of certain dicarboxylic acids. A single example of such a material is given. The dicarboxylic acid half-esters would tend to hydrolyse in the wash liquor and thereby increase affinity of the material for a cotton fabric. However, first, this mechanism of action or behaviour is not mentioned. Second, the hydrolysis rate of such dicarboxylic acids half esters is not as great as that of esters of monocarboxylic acids (which are not disclosed or claimed in WO-A-99/14295). Third, the degree of substitution for this variant is specified as being from 0.001 to 0.1. This is so low as to make the enhancement of fabric affinity too low to be worthwhile for this mechanism of action. Fourth, the structures described and claimed insofar as they have such half ester substituents, must also have substituents of the type which are carboxyalkyl groups or esters thereof, i.e. of the type also described in WO-A-99/14245. In the latter (ester) case, these would hydrolyse to the free acid form. The degree of substitution of the latter (0.2 to 2) is considerably higher than for the half-ester groups and the resultant increase in solubility would easily negate any enhanced affinity for the fabric by hydrolysis of the half-ester groups.
The perfume deposition effect is not studied in WO 99/14295.
DEFINITION OF THE INVENTION
Thus, a first aspect of the present invention now provides a method of improving perfume deposition onto fabrics in a laundry treatment process and/or retention of perfume on laundered fabrics, comprising using a laundry treatment composition comprising a water-soluble or water-dispersible rebuild agent for deposition onto a fabric during the laundry treatment process wherein the rebuild agent undergoes during the laundry treatment process, a chemical change by which change the affinity of the rebuild agent for the fabric is increased, said chemical change resulting in the loss or modification of one or more groups covalently bonded to be pendant to a polymeric backbone of the rebuild agent via an ester linkage, the ester-linked group(s) being selected from monocarboxylic acid esters.
In the first aspect of the invention, the polymeric backbone of the rebuild agent preferably comprises cellulose units or other &bgr;-1,4 linked polysaccharide units. Moreover, the average degree of substitution of all pendant group(s), i.e. all the group(s) which undergo the chemical change plus any other groups per saccharide rings for the totality of saccharide rings in the rebuild agent is preferably from 0.3 to 3, more preferably from 0.4 to 1, still more preferably from 0.5 to 0.75 and most preferably from 0.6 to 0.7.
Throughout this specification, “average degree of substitution” refers to the number of substituted pendant groups per saccharide ring, averaged over all saccharide rings of the rebuild agent. Each saccharide ring prior to substitution has three —OH groups and therefore, an average degree of substitution of 3 means that each of these groups on all molecules of the sample, bears a substituent.
By ester linkage is meant that the hydrogen of an —OH group has been replaced by a substituent such as R′—CO—, R′SO
2
— etc to form a carboxylic acid ester, sulphonic acid ester (as appropriate) etc together with the remnant oxygen attached to the saccharide ring. In some cases, the group R′ may for example contain a heteroatom, e.g. as an —NH— group, attached to the carbonyl, sulphonyl etc group, so that the linkage as a whole could be regarded as a urethane etc linkage. However, the term ester linkage is still to be construed as encompassing these structures. The compositions used in the second aspect are not limited to those incorporating rebuild agents incorporating monocarboxylic acid ester linkages.
A second aspect of the present invention provides a method of improving perfume deposition onto fabrics in a laundry treatment process and/or retention of perfume on laundered fabrics, comprising using a laundry treatment composition comprising a water-soluble or water-dispersible rebuild agent for deposition onto a fabric during a laundry treatment process wherein the rebuild agent undergoes during the laundry treatment process, a chemical change by which change the affinity of the rebuild agent for the fabric is increased, wherein the chemical change occurring in or to a group or groups covalently bonded to be pendant on a polymeric backbone of the rebuild agent and which backbone comprises cellulose units or other &bgr;-1,4 linked polysaccharide units, the average degree of substitution of the total of all group(s) pendant on the saccharide rings of the backbone being from 0.4 to 3, preferably from 0.4 to 1, more preferably from 0.5 to 0.75, most preferably from 0.6 to 0.7.
Optionally, compositions as defined for both the first and second aspects of t
Finch Timothy David
Hopkinson Andrew
Bornstein Alan A.
Hardee John
Unilever Home & Personal Care USA a division of Conopco, Inc.
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