Cleaning compositions for solid surfaces – auxiliary compositions – Cleaning compositions or processes of preparing – For cleaning a specific substrate or removing a specific...
Reexamination Certificate
1998-11-23
2001-01-09
Gupta, Yogendra (Department: 1751)
Cleaning compositions for solid surfaces, auxiliary compositions
Cleaning compositions or processes of preparing
For cleaning a specific substrate or removing a specific...
C510S299000, C510S361000, C510S475000, C510S476000
Reexamination Certificate
active
06172027
ABSTRACT:
The invention relates to the use of water-soluble copolymers based on N-vinylimidazole and N-vinylpyrrolidone as color transfer inhibitors in detergents.
DE-A 2 814 287 discloses detergents which contain 0.1-10% by weight of a water-soluble or -dispersible homo- or copolymer of N-vinylimidazole as discoloration-inhibiting additive. The copolymers contain at least 25 mol % of N-vinylimidazole units.
EP-A 0 635 565 discloses detergent formulations which contain copolymers of N-vinylimidazole and N-vinylpyrrolidone with an average molecular weight of 5000 to 50,000. The minimum N-vinylimidazole content in the copolymers is 20 mol %. According to EP-A 0 635 566, the abovementioned copolymers are used as color transfer inhibitors in detergents whose surfactant system is free of alkylbenzenesulfonates. The detergents may contain cellulases or peroxidases as enzyme where appropriate.
The known low molecular weight color transfer inhibitors with vinylimidazole contents above 20% show, in the laundering of colored textiles, besides the required effect of color transfer inhibition also an upsetting color-releasing effect. In addition, large contents of anionic surfactants and of polycarboxylates in detergents adversely affect the efficacy of the known color transfer inhibitors.
It is an object of the present invention to provide color transfer inhibitors for use in detergents, which in the laundering of colored textiles have less of a color-releasing effect on the colored textiles than do known color transfer inhibitors, and whose efficacy is not reduced by anionic surfactants and polycarboxylates to the extent found with known color transfer inhibitors.
We have found that this object is achieved by the use of water-soluble copolymers which comprise
(a) 5-20 mol % of N-vinylimidazole or 4-vinylpyridine N-oxide units,
(b) 95-50 mol % of N-vinylpyrrolidone, N-vinyloxazolidone, methyl-N-vinylimidazole units or mixtures thereof and
(c) 0-30 mol % of other monoethylenically unsaturated monomer units,
where the total of (a), (b) and (c) in mol % is always 100, and which have an average molecular weight M
w
of more than 50,000, as color transfer inhibitors in detergents.
Suitable copolymers are, with the exception of the polymers comprising 4-vinylpyridine N-oxide, prepared by copolymerizing the monomers on which these copolymers are based. Processes of this type are known, cf., for example, WO-A 94/26796. Copolymers of 4-vinylpyridine N-oxide can be obtained by copolymerizing 4-vinylpyridine with the group (b) and (c) monomers and subsequently oxidizing the vinylpyridine units to vinylpyridine N-oxide units. Polymers comprising vinylpyridine N-oxide units are described as color transfer inhibitors in detergents, for example in WO-A 94/2578.
The content of N-vinylimidazole or 4-vinylpyridine N-oxide units in the copolymers is 5-20, preferably 5-17.5, mol %. Copolymers comprising 8-15% mol % of N-vinylimidazole units are particularly preferred.
The copolymers comprise as component (b) 95-50 mol % of N-vinylpyrrolidone, N-vinyloxazolidone, methyl-N-vinylimidazole or mixtures of said compounds as copolymerized units. Both 2-methyl-N-vinylimidazole and 4-methyl-N-vinylimidazole units or mixtures thereof can be present in the copolymers. The copolymers comprise 95-50, preferably 62.5-95, mol % of at least one compound of component (b) as copolymerized units. Copolymers which comprise
(a) 8-15 mol % of N-vinylimidazole units and
(b) 85-92 mol % of N-vinylpyrrolidone units,
where the total of (a) and (b) in mol % is always 100, are particularly preferred.
The copolymers may comprise where appropriate up to 30 mol % of other monoethylenically unsaturated monomer units, with the total of (a), (b) and (c) in mol % always being 100.
The group (c) monomers are employed to modify the copolymers of components (a) and (b). Examples of suitable group (c) monomers are vinyl esters of saturated carboxylic acids, eg. vinyl formate, vinyl acetate, vinyl propionate or vinyl butyrate, esters of acrylic acid and methacrylic acid derived, in each case, from alcohols having 1 to 8 carbon atoms, in particular methyl acrylate, ethyl acrylate, isopropyl acrylate, n-propyl acrylate, methyl methacrylate and ethyl methacrylate, acrylonitrile, methacrylonitrile, acrylamide and methacrylamide. Esters of other monoethylenically unsaturated carboxylic acids are also suitable as group (c) monomers, for example dimethyl maleate.
The average molecular weight M
w
of the water-soluble copolymers is more than 50,000, for example 55,000 to 2 million. Copolymers with an average molecular weight M
w
of 75,000 to 500,000 are preferably employed according to the invention. The copolymers which are preferably employed comprise
(a) 5-17.5 mol % of N-vinylimidazole or 4-vinylpyridine N-oxide units,
(b) 62.5-95 mol % of N-vinylpyrrolidone, N-vinyloxazolidone, methyl-N-vinylimidazole units or mixtures thereof and
(c) 0-20 mol % of other monoethylenically unsaturated monomer units,
where the total of (a), (b) and (c) is always 100. The copolymers described above are present in detergent formulations in amounts of 0.05-5.0, preferably 0.1-2.0, % by weight. In the laundering of colored textiles they act as color transfer inhibitors in the wash liquor. They are employed both in heavy duty detergents and in color detergents. The copolymers to be used according to the invention are usually present in color-sparing color detergents in amounts of 0.1-1.5, preferably 0.2-1.0, % by weight.
The detergents comprising the copolymers to be used according to the invention may be in powder form or else in a liquid formulation. They contain the anionic and/or nonionic surfactants which are conventionally used in amounts of 2-50, preferably 8-30, % by weight. Phosphate-free or reduced phosphate detergents are particularly preferably produced having a phosphate content not exceeding 25%, calculated as pentasodium triphosphate. The detergents may also be in the form of granules or as compact detergents having a density of 500-950 g/l.
The detergents may be heavy duty detergents or specialty detergents. Suitable surfactants are both anionic and nonionic or mixtures of anionic and nonionic surfactants. The surfactant content of the detergents is preferably 8-30% by weight.
Examples of suitable anionic surfactants are fatty alcohol sulfates from fatty alcohols having 8-22, preferably 10-18, carbon atoms, eg. C
9
-C
11
-alcohol sulfates, C
12
-C
13
-alcohol sulfates, cetyl sulfate, myristyl sulfate, palmityl sulfate, stearyl sulfate and tallow fatty alcohol sulfate.
Other suitable anionic surfactants are sulfated, ethoxylated C
8
-C
22
-alcohols or soluble salts thereof. Compounds of this type are prepared, for example, by initially alkoxylating a C
8
-C
22
-, preferably a C
10
-
18
-, alcohol and subsequently sulfating the alkoxylation product. Ethylene oxide is preferably used for the alkoxylation, in which case 2-50, preferably 3-20, mol of ethylene oxide are employed per mole of fatty alcohol. However, the alcohols can also be alkoxylated with propylene oxide, alone or with butylene oxide. Also suitable are alkoxylated C
8
-C
22
-alcohols comprising ethylene oxide and propylene oxide or ethylene oxide and butylene oxide. The alkoxylated C
8
-C
22
-alcohols may contain the ethylene oxide, propylene oxide and butylene oxide units in the form of blocks or in random distribution.
Other suitable anionic surfactants are alkylsulfonates such as C
8
-C
24
-, preferably C
10
-C
18
-, alkanesulfonates, and soaps such as the salts of C
8
-C
24
-carboxylic acids.
Other suitable anionic surfactants are linear C
9
-C
20
-alkylbenzene-sulfonates (LAS). The polymers according to the invention are preferably employed in detergent formulations containing less than 4% of LAS, particularly preferably in LAS-free formulations.
The anionic surfactants are preferably added in the form of salts to the detergent. Suitable cations in the salts are alkali metal ions such as sodium, potassium and lithium ions, and ammonium ions such as hydroxyethylammonium, di(hydroxyethyl)ammonium and
Boeckh Dieter
Funhoff Angelika
J{umlaut over (a)}ger Hans-Ulrich
Lux J{umlaut over (u)}rgen Alfred
Stein Stefan
BASF - Aktiengesellschaft
Gupta Yogendra
Ingersoll Christine
Oblon & Spivak, McClelland, Maier & Neustadt P.C.
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