Drug – bio-affecting and body treating compositions – Live hair or scalp treating compositions
Reexamination Certificate
1998-10-08
2002-03-12
Page, Thurman K. (Department: 1615)
Drug, bio-affecting and body treating compositions
Live hair or scalp treating compositions
C424S070110, C424S070160, C424S070122, C526S262000, C526S265000
Reexamination Certificate
active
06355231
ABSTRACT:
The present invention relates to the use of cationic polymers obtainable by free-radically initiated copolymerization of monomer mixtures comprising
(a) from 60 to 99% by weight of a 1-vinylimidazole or of a quaternized 1-vinylimidazole,
(b) from 1 to 40% by weight of an unsaturated acid or of salts of such an acid,
(c) from 0 to 30% by weight of a further free-radically copolymerizable monomer
and optional subsequent quaternization of the polymer, as active ingredients in cosmetic hair formulations, especially as conditioning agents in shampoos.
The purpose of shampoos for hair is to free the hair from dirt. In addition to this cleansing effect, modern shampoos perform conditioning functions as well. The conditioning effect is achieved by virtue of the presence of conditioning agents in the shampoo composition.
Examples of conditioning agents employed in shampoos are, in particular, silicones and cationic polymers. The silicones have the disadvantage that they are generally insoluble in water and so must be stabilized in the shampoo formulation by means of dispersants. These additives are undesirable. In addition, silicones show a strong accumulation effect; in other words, they attach to the hair and are not completely removed by washing. After a certain time, the hair feels unpleasantly heavy.
The cationic polymers used as conditioning agents in shampoos, such as cationic cellulose derivatives, however, form—together with the anionic surfactants in the shampoo formulation—surfactant-polymer complexes which are insoluble in water when the polymers have a high charge density. Consequently, it is common to employ cationic polymers having a low charge density, which are hence soluble in the formulation.
Since, however, cationic polymers with a high charge density have a greater affinity for the hair, it is desirable to employ highly charged polymers in shampoos. Then, however, the surfactant-polymer complexes are insoluble in the formulation, and the latter has to be stabilized by adding dispersing auxiliaries.
For instance, WO 94/06403 proposes the use of, inter alia, copolymers of N-vinylpyrrolidone and 3-methyl-1-vinylimidazolium salts of high charge density, in combination with further water-insoluble conditioning agents, in shampoo formulations. The formulations are stabilized accordingly using dispersants. WO 94/06409 and U.S. Pat. No. 5,580,494, furthermore, describe shampoo compositions based on an alpha-olefinsulfonate as detergent and on a cationic copolymer of high charge density, for example a copolymer of N-vinylpyrrolidone and 3-methyl-1-vinylimidazolium salts, as conditioning agent. Here too, however, the formulations must be stabilized by adding dispersing auxiliaries.
EP-A 246 580, moreover, discloses the use of quaternized vinylimidazole copolymers with various other monomers, but not including polymerizable unsaturated acids, as hair conditioning agents. The polymers described therein have the disadvantage that if the proportion of quaternized vinylimidazole monomers is small there is little effect in the presence of anionic surfactants whereas if the proportion of the quaternized vinylimidazole is high the resulting dispersions are not stable.
It is an object of the present invention to find cationic polymers of high charge density which can be employed without addition of dispersing auxiliaries in shampoo formulations comprising anionic surfactants.
We have found that this object is achieved by the use of cationic copolymers obtainable by free-radically initiated copolymerization of
(a) from 60 to 99% by weight, preferably from 65 to 95% by weight and, with particular preference, from 70 to 90% by weight of a substituted or unsubstituted 1-vinylimidazole or of a quaternized 1-vinylimidazole,
(b) from 1 to 40% by weight, preferably from 5 to 35% by weight and, with particular preference, from 10 to 30% by weight of an acid containing a polymerizable double bond, or of salts of such an acid, and
(c) from 0 to 30% by weight, preferably from 0 to 20% by weight and, with particular preference, from 0 to 10% by weight of a further free-radically copolymerizable monomer
and subsequent quaternization of the polymer if a nonquaternized 1-vinylimidazole is employed as monomer (a), as active ingredients in cosmetic hair formulations, especially as conditioning agents in shampoos.
The quaternization of the polymers in this context is generally conducted so as to give complete quaternization of the vinylimidazole units. Alternatively, it is possible to perform only a partial quaternization, for example up to 80% and, preferably, more than 90% quaternization.
Suitable monomers (a) are 1-vinylimidazole or its derivatives of the formula I
in which R
1
to R
3
independently are hydrogen, C
1
C
4
-alkyl or phenyl.
1-vinylimidazole and 2-methyl-1-vinylimidazole are preferred.
To quaternize the compounds of the formula I use is made appropriately of conventional methods of adding on alkyls, aralkyls or hydroxyalkyls, examples of such methods being reaction with alkyl halides of 1 to 24 carbons, such as methyl chloride, methyl bromide, methyl iodide, ethyl chloride, ethyl bromide, propyl chloride, hexyl chloride, dodecyl chloride, lauryl chloride and with benzyl halides, especially benzyl chloride and benzyl bromide. Further particularly suitable quaternizing agents are dialkyl sulfates, especially dimethyl sulfate or diethyl sulfate. The quaternization of the base monomers or polymers can also be conducted with alkylene oxides, such as ethylene oxide or propylene oxide, in the presence of acids.
Preferred quaternizing agents are: methyl chloride, dimethyl sulfate and diethyl sulfate.
Monomers (b) are, for example, unsaturated carboxylic acids of 2 to 8 carbons, such as acrylic, methacrylic, dimethylacrylic, ethacrylic, crotonic, itaconic, methylenemalonic and maleic acid and maleic monoesters, fumaric acid and fumaric monoesters. Also suitable are unsaturated sulfonic acids, such as vinylsulfonic or acrylamidomethylpropanesulfonic acid, and also unsaturated phosphonic acids, an example of which is vinylphosphonic acid. The unsaturated acids can be either in the form of the free acids or in partly or fully neutralized form in the copolymers. The monomers are neutralized if appropriate with alkali metal hydroxides, such as sodium hydroxide or potassium hydroxide, or with ammonia or amines.
Preferred monomers (a) are acrylic, methacrylic and acrylamidomethylpropanesulfonic acid.
Suitable monomers (c) are all those which are copolymerizable with the monomers (a) and (b). Suitable examples are N-vinyllactams, such as N-vinylpiperidone, N-vinylpyrrolidone or N-vinylcaprolactam, and also N-vinylacetamide, N-methyl-N-vinylacetamide, acrylamide, methacrylamide, N,N-dimethylacrylamide, N-methylolmethacrylamide, N-vinylformamide, N-vinyloxazolidone, N-vinyltriazole, hydroxyalkyl (meth)acrylates, such as hydroxyethyl (meth)acrylate and hydroxypropyl (meth)acrylates, or alkyl ethylene glycol (meth)acrylates having 1 to 50 ethylene glycol units in the molecule. Also suitable are dialkylaminoalkyl acrylates and methacrylates, such as dimethylaminoethyl methacrylate, or dialkylaminoalkylacrylamides and methacrylamides, an example being dimethylaminopropylmethacrylamide.
Mention should also be made of C
1
-C
24
-, especially C
1
C
10
-alkyl esters of acrylic or methacrylic acid, examples of which are methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, tert-butyl acrylate, tert-butyl methacrylate, isobutyl acrylate, n-butyl acrylate, and acrylamides such as N-tert-butylacrylamide and N-tert-octylacrylamide. It is also possible to employ vinyl carboxylates such as vinyl acetate or vinyl propionate, for example.
The monomers of groups (a) to (c) can in each case be employed individually or in a mixture with further monomers from the same group.
Particular preference is given to copolymers of
(a) from 70 to 90% by weight of 3-methyl-1-vinylimidazoleium chloride or the corresponding methyl sulfate and
(b) from 10 to 30% by weight of acrylic acid, methacrylic acid or acrylam
Dieing Reinhold
Hössel Peter
Sanner Axel
BASF - Aktiengesellschaft
Keil & Weinkauf
Tran S.
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