Patent Application
20060074002
Partially esterified copolymers of monoethylenically unsaturated dicarboxylic anhydrides, vinylaromatic compounds and further monoethylenically unsaturated monomers containing heteroatoms
The present invention relates to copolymers which are obtainable by free-radical polymerization of
Furthermore, the invention relates to the use of these copolymers as additive for detergents and cleaners, in particular as graying-inhibiting and detergency-boosting additive in detergents, and also to solid and liquid detergents which comprise the copolymers as additive.
In the washing process, a distinction is drawn between primary and secondary detergency. Primary detergency is understood as meaning the actual removal of soiling from the textile ware. Secondary detergency is understood as meaning the prevention of the effects which arise as the result of redeposition of the detached soiling from the wash liquor onto the fabric. The textiles become increasingly gray from washing operation to washing operation and this insidious graying process can scarcely be reversed. In order to protect textiles made of cotton from becoming gray, sodium salts of carboxymethylcellulose (CMC) are often added to the detergent. Polyacrylic acids and acrylic acid-maleic acid copolymers also have a graying-inhibiting action. However, the action of said polymers is not satisfactory for clay-containing soiling.
EP-A-945 473 and 945 501 describe graft copolymers of styrene, maleic anhydride and polyethylene glycols which are used as soil repellent additive in cleaning formulations and detergents.
U.S. Pat. No. 3,485,762 discloses detergent compositions which comprise ammonium salts of a styrene-maleic anhydride copolymer partially esterified with a nonionic surfactant as detergency booster.
Styrene-maleic anhydride copolymers partially esterified with polyethylene glycols are also known from EP-A-306 449, according to which they can be used as cement liquefiers.
It is an object of the present invention to provide polymeric detergent additives which are characterized by overall advantageous application properties, in particular have improved primary and secondary detergency and can be readily and stably incorporated into solid and liquid detergent formulations.
We have found that this object is achieved by copolymers which are obtainable by free-radical polymerization of
As a rule, the copolymers according to the invention have the following composition: the molar ratios of (B) to (A) and of (C) to (A) are in each case in the range from 0.1:1 to 10:1, where the molar ratio of [(B)+(C)] to (A) is 20:1 to 1:2.
In this connection, for the molar ratio of (B) to (A), a range from 0.2:1 to 5:1 is preferred, and from 0.3:1 to 3:1 is particularly preferred.
The molar ratio of (C) to (A) is preferably 0.1:1 to 5:1, in particular 0.1:1 to 3:1.
The molar ratio of [(B)+(C)] to (A) is preferably 10:1 to 1:1 and particularly preferably 6:1 to 1:1.
Used as monomer (A) for the preparation of the copolymers according to the invention are monoethylenically unsaturated dicarboxylic anhydrides having 4 to 8 carbon atoms. Examples which may be specifically mentioned are maleic anhydride, itaconic anhydride, citraconic anhydride and methylenemalonic anhydride. Preference is given here to itaconic anhydride and in particular maleic anhydride.
The vinylaromatic monomers (B) used are styrene and substituted styrenes, such as alkylstyrenes, in particular C1-C4-alkylstyrenes, e.g. methylstyrenes and ethylstyrenes, styrenesulfonic acids and salts thereof and halogenated styrenes, in particular chlorostyrenes, very particular preference being given to unsubstituted styrene.
Suitable as monomer (C) are a number of monoethylenically unsaturated compounds having at least one heteroatom. The heteroatoms, e.g. nitrogen or oxygen atom, can be incorporated into the carbon chain or be present in the form of a functional group, e.g. a carboxyl, ester, amide or cyano group.
Examples of particularly suitable monomers (C) which may be mentioned are:
Preferred monomers (C) are acrylic acid, methacrylic acid, (meth)acrylic esters and amides, in particular methyl acrylate, methyl methacrylate and acrylamide, vinyl alkyl ethers, in particular vinyl n-butyl ether and vinyl isobutyl ether, N-vinylamides, in particular N-vinylformamide and N-vinylpyrrolidone, and vinyl-substituted nitrogen heterocycles, in particular 1-vinylimidazole and 4-vinylpyridine.
The esterification component (D) used are alcohol alkoxylates of the formula I
Here, R is linear or branched C2-C6-alkylene, preferably ethylene, propylene or butylene. The radicals R can, when n is >1, be identical or different. Different radicals R may be arranged blockwise or randomly.
R1 is linear or branched C1-C30-alkyl.
Finally, n is 1 to 200, preferably 4 to 100, particularly preferably 4 to 50.
Examples of particularly suitable components (D) are:
The copolymers according to the invention are partially esterified with the alcohol alkoxylates 1. In general, 5 to 80%, preferably 10 to 65%, particularly preferably 20 to 50%, of the carboxyl groups present are esterified.
Preferably, the copolymers according to the invention do not contain anhydride groups, i.e. unesterified anhydride groups are hydrolyzed to carboxyl groups. The hydrolysis can be carried out with water or in particular with aqueous bases, as a result of which the carboxyl groups are converted to the corresponding salts.
The K values of the copolymers according to the invention are usually 6 to 200, in particular 10 to 100 (measured in accordance with H. Fikentscher at 25° C. in water and a polymer concentration of 1% by weight).
The preparation of the copolymers according to the invention can take place by solution polymerization, suspension polymerization or solvent-free by bulk polymerization of the monomers (A), (B) and (C) and subsequent partial esterification with (D), and, if desired, hydrolysis.
Suitable solvents here are polar solvents which are inert toward the acid anhydrides (A), e.g. acetone, tetrahydrofuran or dioxane. Suitable precipitating agents are, for example, toluene, xylene or aliphatic hydrocarbons.
The polymerization generally takes place at temperatures of from 40 to 200° C., preferably 60 to 150° C., over the course of 0.5 to 12 h, preferably 1 to 8 h and particularly preferably 1 to 5 h.
The polymerization is triggered in all of the processes using polymerization initiators. Suitable polymerization initiators here are all compounds which decompose into free radicals, e.g. peroxides, hydroperoxides, redox initiators and azo compounds, such as di-tert-butyl peroxide, tert-butyl peroctoate, tert-butyl perpivalate, tert-butyl per-2-ethylhexanoate, tert-butyl permaleate, tert-butyl perisobutyrate, benzoyl peroxide, diacetyl peroxide, succinyl peroxide, p-chlorobenzoyl peroxide, dicyclohexyl peroxide dicarbonate, 2,2′-azobis(isobutyronitrile), 2,2′-azobis(2-methylpropionamidine) dihydrochloride and 2,2′-azobis(4-methoxy-2,4-dimethylvaleronitrile). In general, these initiators are used in amounts of from 0.1 to 20% by weight, preferably 0.2 to 15% by weight, based on the weight of the monomers (A), (B) and (C).
The esterification of the copolymers with the alcohol alkoxylate (D) can be carried out in inert solvents or swelling agents, such as acetone, methyl ketone, tetrahydrofuran, toluene, xylene or aliphatic hydrocarbons, or in bulk. The amount of (D) is chosen here such that only partial esterification of the copolymers arises. The esterification can be accelerated by adding catalysts, in particular acidic catalysts, such as sulfuric acid, methanesulfonic acid, p-toluenesulfonic acid, dodecylbenzenesulfonic acid, hydrochloric acid or acidic ion exchangers. Following the esterification, the solvents, where used, are removed from the reaction mixture. If required, the partially esterified copolymers obtained are dissolved in water with the addition of bases. As a result, anhydride groups which are still present are hydrolyzed and converted to carboxylate groups. Suitable bases are, for example, sodium hydroxide solution, potassium hydroxide solution, ammonia, amines and alkanolamines. The pH of the copolymer solutions obtained in this way is generally 3 to 10 and preferably 5 to 8.
It is particularly advantageous for the alcohol alkoxylate (D) itself to be used as solvent or diluent for the copolymerization of (A), (B) and (C). When the copolymerization is complete, the reaction with (D) can be started or completed by increasing the temperature and/or adding catalysts. The solvent removal required when using other solvents, e.g. by distillation, can be dispensed with here. In this procedure, graft products of the reactants may also arise in a small fraction.
It is also possible to firstly hydrolyze the copolymers containing anhydride groups so that all of the anhydride groups are present as carboxyl groups, and then to carry out the esterification with (D) in accordance with known methods. Preference is given, however, to the procedure described above.
In addition, the copolymers according to the invention are also obtainable by firstly reacting (A) and (D) to give monoethylenically unsaturated mono- or diesters and then copolymerizing these with (B) and (C), the reaction being carried out such that 5 to 80% of the carboxyl groups present in the copolymer according to the invention are in esterified form.
The copolymers according to the invention are advantageously suitable as additive for cleaners, in particular cleaners for hard surfaces, such as dishwashing and household cleaners, and detergents.
The copolymers according to the invention are characterized here in particular by the following advantageous application properties, which render them particularly suitable for use in detergents: they disperse particles of soiling in an excellent manner and thus prevent redeposition of the soiling onto the fabric during washing. They thus prevent graying of the textiles. In addition, they improve the primary detergency both of liquid and of solid detergents. This is true particularly for particulate soilings, but hydrophobic, oil- and grease-containing fabric soilings are also removed more easily. In addition, they can be incorporated into solid and liquid detergent formulations without problems. In this connection, it should be emphasized that stability and homogeneity of the liquid detergents are not impaired by the copolymers according to the invention. Undesired phase formations and precipitations are not observed even upon prolonged storage.
The invention accordingly also provides detergent formulations which comprise the copolymers according to the invention as additive. The copolymers according to the invention can be used here in the form of the free acids or in partially or completely neutralized form.
Solid detergent formulations according to the invention comprise, in particular, the following components:
The solid detergent formulations according to the invention may be in the form of powders, granules, extrudates or tablets.
Liquid detergent formulations according to the invention preferably have the following composition:
Suitable nonionic surfactants (b) are in particular:
Suitable anionic surfactants are, for example:
The anionic surfactants are added to the detergent preferably in the form of salts. Suitable cations in this connection are, for example, alkali metal ions, such as sodium, potassium and lithium, and ammonium salts, such as hydroxyethylammonium, di(hydroxyethyl)ammonium and tri(hydroxyethyl)ammonium salts.
Particularly suitable cationic surfactants which may be mentioned are:
Suitable inorganic builders are, in particular:
Suitable organic cobuilders are, in particular:
Suitable bleaches are, for example, adducts of hydrogen peroxide onto inorganic salts, such as sodium perborate monohydrate, sodium perborate tetrahydrate and sodium carbonate perhydrate, and percarboxylic acids, such as phthalimidopercaproic acid.
Suitable bleach activators are, for example, N,N,N′,N′-tetraacetylethylenediamine (TAED), sodium p-nonanoyloxybenzenesulfonate and N-methylmorpholinium acetonitrile methylsulfate.
Enzymes preferably used in detergents are proteases, lipases, amylases, cellulases, oxidases and peroxidases.
Suitable color transfer inhibitors are, for example, homopolymers, copolymers and graft polymers of 1-vinylpyrrolidone, 1-vinylimidazole and 4-vinylpyridine N-oxide. Homopolymers and copolymers of 4-vinylpyridine reacted with chloroacetic acid are also suitable as color transfer inhibitors.
Detergent ingredients are otherwise generally known. Detailed descriptions are given, for example, in WO-A-99/06524 and 99/04313; in Liquid Detergents, editor: Kuo-Yann Lai, Surfactant Sci. Ser., Vol. 67, Marcel Decker, New York, 1997, pp. 272-304.
I. Preparation of Copolymers According to the Invention
Copolymers 1 to 9
108 g (1.10 mol) of maleic anhydride (A1) were dissolved in x1 g (x2 mol) of the alcohol alkoxylate (D) and heated to 90° C. under nitrogen and with stirring. At this temperature, 6 g of tert-butyl peroctoate, dissolved in a small partial amount of the alcohol alkoxylate (D), and a solution of y1 g (y2 mol) of the monomer (C) in z1 g (z2 mol) of styrene were slowly added dropwise over 2 h.
The resulting reaction mixture was then stirred for 4 h at 150° C. The resulting oil was taken up in 500 g of water, and the solution was adjusted to pH 6-7 with sodium hydroxide solution.
30 to 45% strength by weight low-viscosity polymer solutions were obtained. The K values of the copolymers prepared were determined in accordance with H. Fikentscher, Cellulose-Chemie, volume 13, 58-64 and 761-774 (1932) in aqueous solution at 25° C. and a polymer concentration of 1% by weight. Further details relating to these experiments and also the results thereof are summarized in table 1.
The alcohol alkoxylates (D) used were:
D1: methylpolyethylene glycol with an average molecular weight Mn of 500
D2: methylpolyethylene glycol with an average molecular weight Mn of 1 000
D3: ethoxylated C13C15-oxo alcohol (7 mol of EO/mol)
Copolymers 10 to 14
a) reparation of the precursors
a1) Precursor PC1 for copolymers 10 to 12:
194 g (2.11 mol) of maleic anhydride (A1) and 20 g of polyethyl vinyl ether (K value 50, 1% strength by weight in cyclohexane at 25° C. in accordance with H. Fikentscher) were dissolved in 900 g of xylene and heated to 140° C. under nitrogen and with stirring. At this temperature, a mixture of 220 g (2.16 mol) of styrene and 158 g (2.20 mol) of acrylic acid, and a solution of 4 g of di-tert-butyl peroxide in 36 g of xylene were added in parallel over the course of 4 h.
After after-stirring for one hour at 140° C. and cooling to 50° C., the solvent was removed under reduced pressure.
The K value of the polymer present in the form of a white powder was 15.9 (1% strength by weight in cyclohexanone at 25° C.).
a2) Precursor PC2 for copolymers 13 and 14:
228 g (2.32 mol) of maleic anhydride (A1) and 20 9 of polyethyl vinyl ether (K value 50, 1% strength by weight in cyclohexane at 25° C. in accordance with H. Fikentscher) were dissolved in 1 100 g of xylene and heated to 140° C. under nitrogen and with stirring. At this temperature, a mixture of 230 g (2.25 mol) of styrene and 1 300 g (18.06 mol) of acrylic acid, and a solution of 12 g of di-tert-butyl peroxide in 140 g of xylene were added in parallel over 4 h.
After after-stirring for one hour at 140° C. and cooling to 50° C., the solvent was removed under reduced pressure.
The K value of the polymer present in the form of a white powder was 24.2 (1% strength by weight in cyclohexanone at 25° C.).
b) Conversion of the Precursors to the Copolymers
To prepare the copolymers 10 to 14, in each case a mixture of the precursors PCl and PC2 and x mol of the alcohol alkoxylate (D) per mole of maleic anhydride were heated to 170° C. under nitrogen and with stirring.
After stirring for four hours at 170° C. and cooling to 50° C., the resulting oil was dispersed with sodium hydroxide solution. The molar ratio of sodium hydroxide solution to (maleic anhydride+acrylic acid) was 0.6:1.0, giving 30 to 40% strength by weight dispersions of the copolymers with a pH of from 6 to 7.
Further details relating to these experiments and the results thereof are summarized in table 2.
The alcohol alkoxylates (D) used were:
D6: C13C15-oxo alcohol (12 mol of EO/mol, 3 mol of PO/mol)
II. Use of Copolymers According to the Invention in Detergents
Primary and secondary detergency of the copolymers according to the invention was determined.
For the washing experiments, three solid detergent formulations (DT 1 to 3) and 2 f copolymers according to the invention in detergents liquid detergent formulations (DT 4 and 5) were used, the composition of which is given in table 3. The washing conditions are listed in table 4.
To determine the primary detergency, the degree of whiteness of the soiled fabric was measured before and after washing using a Datacolor photometer (Elrepho® 2000) by reference to the reflectance (%). The higher the reflectance value, the better the primary detergency.
The results obtained are summarized in table 5.
To determine the secondary detergency, the graying of the white test fabric was measured by determining the degree of whiteness before and after washing using a Datacolor photometer (Elrepho® 2000) by reference to the reflectance (%). The greater the drop in the degree of whiteness, the greater the graying of the fabric, and vice versa.
The results obtained are summarized in table 6.
To ascertain the stability of the copolymers in various liquid detergent formulations, in each case 1% by weight of copolymer was formulated into the liquid detergent, and a visual assessment with regard to phase separation, clouding, incompatibilities, etc. was undertaken.
The stability tests were carried out with liquid detergent formulations DT 4 and 5.
Table 7 summarizes the visual assessments after storage for 4 weeks at 40° C.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10301009.2 | Jan 2003 | DE | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/EP03/14878 | 12/24/2003 | WO | 7/8/2005 |
