Cleaning compositions for solid surfaces – auxiliary compositions – Cleaning compositions or processes of preparing – With oxygen or halogen containing chemical bleach or oxidant...
Reexamination Certificate
2001-03-29
2002-03-19
Kopec, Mark (Department: 1751)
Cleaning compositions for solid surfaces, auxiliary compositions
Cleaning compositions or processes of preparing
With oxygen or halogen containing chemical bleach or oxidant...
C510S471000, C510S287000
Reexamination Certificate
active
06358903
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a laundry treatment composition containing a fabric rebuild agent for deposition onto fabric during a washing, rinsing or other treatment process. It further extends to a method of enhancing the effect of rebuild agent.
BACKGROUND OF THE INVENTION
Repeated washing of garments, particularly those comprising cotton or other cellulosic fibres, causes gradual loss of material from individual fibres and the loss of whole fibres from the fabric. These processes of attrition result in thinning of the fabric, eventually rendering it semi-transparent, more prone to accidental tearing and generally detracting from its original appearance.
Hitherto, there has been no way of minimising this kind of damage except by employing less frequent washing and use of less harsh detergent products and/or wash conditions, which obviously tends to less effective cleaning.
In laundry cleaning or treatment products, it is essential for some ingredients to be deposited onto and adhere to the fabric for them to deliver their beneficial effects. Typical examples are fabric conditioners or softeners. Nevertheless, the benefits conferred by such conventional materials do not include rebuilding the fabric.
It has been found possible to include in laundry products, agents which deposit cellulose or cellulose-like materials onto the fabric to at least partially replace the lost material of the fibre.
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.
Our prior copending application no. PCT/EP99/07422, published on Apr. 6, 2000 discloses a laundry treatment composition comprising a water-soluble or water dispersible rebuild agent for deposition onto a fabric during a treatment process, wherein the rebuild agent undergoes, during the treatment process, a chemical change by which the affinity of the rebuild agent for the fabrics is increased, the chemical change resulting in the loss or modification of one or more groups covalently bonded to be dependent to a polymeric backbone of a rebuild agent. In one aspect, the pendant covalent group is derived from monocarboxylic acid bonded via an ester link to the polymeric backbone. In another aspect, the average degree of substitution of groups capable of undergoing the chemical change is in the range 0.3-3.0.
It is further disclosed that compositions comprising the fabric rebuild agent may comprise bleach.
The present inventors have now discovered that certain selected fabric rebuild agents disclosed in PCT/EP99/07422 have an increased deposition in the presence of peroxygen bleach.
DEFINITION OF THE INVENTION
In a first aspect, the present invention provides a laundry treatment composition comprising a peroxygen bleach and a water-soluble or water-dispersible rebuild agent for deposition onto a fabric during a treatment process wherein the rebuild agent undergoes during the treatment process, a chemical change by which change the affinity of the rebuild agent for the fabric is increased, the chemical change occurring in or to acetate 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 acetate groups pendant on the saccharide rings of the backbone being from 0.55 to 0.70, the weight average molecular weight of the rebuild agent being in the range 12,000 to 20,000.
In a second aspect, the present invention provides the use of a peroxygen bleach to increase the fabric rebuild effect of a fabric rebuild agent for deposition onto a fabric during a treatment process, which rebuild agent undergoes during the treatment process, a chemical change by which change the affinity of the rebuild agent for the fabric is increased.
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.
The exact mechanism by which any of these rebuild agents exert their effect is not fully understood. Whether or not they can repair thinned or damaged fibres is not known. However, they are capable of replacing lost fibre weight with deposited and/or bonded material, usually of cellulosic type. This can provide one or more advantages such as repair or rebuilding of the fabric, strengthening of the textile or giving it enhanced body or smoothness, reducing its transparency, reducing fading of colours, improving the appearance of the fabric or of individual fibres, improved comfort during garment wear, dye transfer inhibition, increased stiffness, anti-wrinkle, effect and ease of ironing.
Without being bound by any particular theory or explanation, the inventors have conjectured that the mechanism of deposition is as follows.
Cellulose is substantially insoluble in water. Attachment of the acetate groups causes disruption-of the hydrogen bonding between rings of the cellulose chain, thus increasing water solubility or dispersibility. In the treatment liquor, it is believed that the acetate groups are hydrolysed, causing the affinity for the fabric to increase and the polymer to be deposited on the fabric.
DETAILED DESCRIPTION OF THE INVENTION
The Rebuild Agent
The weight average molecular weight (M
w
) of the rebuild agent (as determined by GPC) is in the range 12,000 to 20,000, preferably 15,000 to 20,000.
By water-soluble, as used herein, what is
Hopkinson Andrew
Jones Christopher Clarkson
Mealing David Richard
Bornstein Alan A.
Kopec Mark
Petruncio John M
Unilever Home and Personal Care USA division of Conopco, Inc.
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