Bleaching and dyeing; fluid treatment and chemical modification – Cleaning or laundering
Reexamination Certificate
2001-02-02
2003-04-29
Kopec, Mark (Department: 1751)
Bleaching and dyeing; fluid treatment and chemical modification
Cleaning or laundering
C510S330000, C510S361000, C510S434000, C510S476000, C510S480000, C510S504000, C134S039000, C134S040000, C134S042000
Reexamination Certificate
active
06554869
ABSTRACT:
FIELD OF INVENTION
The present invention relates to polymers which are used in laundry cleaning products, e.g. for incorporation in products for dosing in the wash and/or rinse. They are intended for, but not limited to, soil release benefits in such products.
BACKGROUND OF THE INVENTION
The term “soil release polymer” is used in the art to cover polymeric materials which assist release of soil from fabrics, e.g. cotton or polyester based fabrics. For example, it is used in relation to polymers which assist release of soil direct from fibers. It is also used to refer to polymers which modify the fibers so that dirt adheres to the polymer-modified fibers rather than to the fiber material itself Then, when the fabric is washed the next time, the dirt is more easily removed than if it was adhering the fibers. Although not wishing to be bound by any particular theory or explanation, the inventors believe that the soil release polymers utilised in the present invention probably exert their effect mainly by the latter mechanism.
WO-A-98/23714 discloses water-soluble use of nitrogen-containing soil-release polymers in detergent products. Some of these polymers are formed from acrylamide monomers polymerised with co-monomers which are amines of alkylacrylates. These materials are essentially neutral, i.e. have no substantial overall positive or negative charge. Thus, they are suited to soil release from polyester rather than from cotton.
Another type of nitrogen-containing soil release polymer described in WO-A-98/23714 is formed from dicarboxylic acid monomers and hydrophilic co-monomers which are secondary amines which contain (poly)alkyleneoxy groups. Since these molecules do not have an overall net positive charge, they are also non-substantive to cotton.
A third type of nitrogen-containing soil-release polymer disclosed in WO-A-98/23714 is formed from alkyleneacrylate monomers having a terminal quaternary ammonium group and co-monomers which are (meth)acrylic acid or esters or salts thereof Therefore, such a polymer may have both cationic and anionic groups. Only a single example of such a material is given. This is polymer formed from a cationic monomer, namely methacrylamidopropyl trimethylammonium chloride (MAPTAC), and anionic monomer, namely acrylic acid (AA) and a neutral monomer, namely isobutylacrylate (IsoBuA). These particular cationic and anionic monomers carry, respectively, a single positive and negative charge. However, this particular kind of polymer has proved to be not very suited to soil release.
U.S. Pat. No. 3,749,682 discloses copolymers of polyvinylpyrrodinone (PVP) and vinyl acetate for use as soil anti-redeposition agents.
WO-A-97/42285 discloses cotton soil-release polymers comprising a polyamine backbone and quaternary ammonium cationic groups. However, the present applicants have found that whilst cationic groups give good substantivity to cotton, a high density of cationic positive charges on the polymer gives rise to staining of the fabric.
EP-A-0995791 discloses a broad range of hydrophobically modified polycarboxylate polymers which are said to be useful for promoting soil release from fabrics, particularly cotton and cotton-containing fabrics. The polymers can comprise up to three moieties A, B and C wherein A is a polymerised residue of a monomer selected from one or more C
3
-C
8
monoethylenically unsaturated carboxylic acids, B is a polymerised residue of a monomer slected from one or more C
3
-C
60
alkyl (meth)acrylates, ethoxylated C
1
-C
24
alkyl (meth)acrylates, and poly(alkylene glycol) (meth)acrylates, alkyl or aromatic ethers of poly(alkylene glycol) and the corresponding maleate mono and di-esters thereof, and C is a polymerised residue of a monomer selected from one or more ethylenically unsaturated monomers which are copolymerisable with the monomers in A and B. However, only two specific examples are given which contain both anionic and cationic groups. One such polymer is formed from an anionic monomer, namely acrylic acid (AA), a cationic monomer, namely dialkyldimethyl ammonium chloride (DADMAC), and lauryl (C
12
) methacrylate ethoxylated with 4 moles of ethylene oxide (E4LMA) whereas the other polymer is formed from AA, E4LMA and [2-(methacryloyloxy)ethyl]trimethyl ammonium chloride (MAETMAC) as a cationic monomer. These particular anionic and cationic monomers carry, respectively, a single negative and positive charge. However, it is clear from the examples in question that the number ratio of anionic: cationic charges is >50:1.
According to GB-A-2 104 091, copolymers of anionic and cationic vinyl monomers can be used as detergency builders, for a wide range of detergent products, e.g. for warewashing, hard surface cleaning, textile cleaning and hair products. However, there is no disclosure that these materials are capable of acting as soil-release polymers. They are not well suited to soil release from cotton and can lead to significant staining. Although a wide range of anionic: cationic mole ratios is claimed (from 1:99 to 99:1), in all of the examples, the number ratio of anionic (negative):cationic (positive) charges is 1:1, which again, is not suited to providing the cotton substantivity required of a cotton soil-release polymer.
U.S. Pat. No. 5,783,533 discloses various amphoteric copolymers as Theological modifiers of lamellar phases of detergent or cosmetic compositions. However, there is no disclosure that these materials are capable of acting as soil-release polymers.
JP-A-59135293 discloses detergent compositions which contain an amphoteric copolymer consisting of at least 10 mol % cationic vinyl monomer units, at least 10 mol % anionic vinyl monomer units and at least 10 mol % nonionic vinyl monomer units. The preferred proportion of cationic vinyl monomer units to anionic vinyl monomer units by molar ratio from 1:2 to 2:1. However, there is no disclosure that these materials are capable of acting as soil-release polymers.
U.S. Pat. No. 5,413,731 discloses water-soluble terpolymers which are useful in automatic machine dishwashing detergent formulations. These terpolymers contain as polymerised units (a) from about 92 to about 30% by weight of one or more C
3
-C
6
monoethylenically unsaturated carboxylic acids, (b) from about 5 to about 50% by weight of one or more aminoacryloyl derivatives, and (c) from about 25% by weight of one or more monoethylenically unsaturated monomers polymerisable with (a) and (b). However, there is no disclosure that these materials could be utilised in a composition for washing and/or rinsing landry, nor any suggestions that these terpolymers could act as soil-release polymers.
Thus, there remains a need to obtain soil release in laundry products based on soil-release agents which are copolymers of cationic and anionic monomers, give better substantivity to cotton and therefore, better soil release from cotton fabrics, fewer or no detrimental interactions with LAS or other anionic surfactants, as well as less staining negatives.
DEFINITION OF THE INVENTION
A composition for washing and/or rinsing of laundry, the composition comprising one or more surfactants suitable for use in laundry wash and/or rinsing products and a polymer which is a co-polymer formed of:
(a) one or more anionic monomer units;
(b) one or more cationic monomer units; and
(c) optionally, one or more neutral (uncharged) monomer units;
wherein, the number ratio of the total of all negative charges on the anionic monomer unit(s) to the total of all positive charges on the cationic monomer unit(s) is from 10:1 to 3:1, preferably from 8:1 to 3:1, especially from 17:3 to 3:1.
The applicants have found that these charge ratios (progressively) give the optimum balance of soil release performance with avoidance of staining and detrimental interactions with the LAS or other anionic surfactants.
A second aspect of the invention provides use of a polymer for a method effecting soil-release of a laundry item, the method comprising contacting the laundry item with the said polymer, the polymer being a copolymer f
Aubay Eric
Blokzijl Wilfried
Geffroy Cédric
Mahmood Khalid
Thompson Laurence Griffith
Kopec Mark
Mitelman Rimma
Mruk Brian P.
Unilever Home & Personal Care USA a division of Conopco, Inc.
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