EP0553099B1 - Liquid washing agent with increased viscosity - Google Patents

Abstract

Aqueous, liquid washing agents containing a mixture of anionic and non ionic tensides, in which the proportion of non ionic tensides prevails, may be thickened with alkylpolyglycosides having a linear alkyl group with 8 to 12 carbon atoms and a polymerisation degree in the range between 1.35 and 2.50.

Description

The present invention relates to liquid, aqueous detergents containing certain alkyl polyglycosides as viscosity regulators.

Liquid detergents have recently become increasingly popular with consumers, since they have some handling advantages over powder detergents and are easier to remove greasy or oily soiling. The last-mentioned advantage is based on the fact that liquid detergents can contain large amounts of the nonionic surfactants of the fatty alcohol ethoxylate type which are particularly effective against greasy or oily soiling. The consumer expects such detergents to be offered in highly concentrated form, so that such detergents can be dosed in a smaller amount compared to powder detergents and that they have a certain consistency. This consistency is equated with a high active ingredient content. This applies not only to textile detergents, but also to shampoos, hand washing detergents, dishwashing detergents or cosmetic preparations.

There has been no shortage of attempts to give liquid detergents the desired consistency by adding thickeners. Examples of such thickeners are carboxymethyl cellulose, guar gum, xanthan gum, colloidal silicates or clays. Such thickeners usually do not contribute to the washing result.

GB-A-2 185 991 relates to liquid detergents with a surfactant combination of nonionic and anionic surfactants, the proportion of nonionic surfactants predominating, and at least 6% by weight alkylglycosides as fabric softeners.

EP-A-282 863 describes highly alkaline cleaner concentrates which include contain nonionic surfactants, anionic surfactants and alkyl glucosides.

EP-A-75 995 and EP-A-75 996 claim cleaning compositions which include contain an alkyl polysaccharide and a nonionic surfactant; Optionally, anionic surfactants can also be included. The older, but not prepublished, application EP-A-405 967 relates to liquid detergents which contain 5-22% by weight of ethoxylated nonionic surfactant, 20-50% by weight of anionic surfactant and 3-11% by weight of alkyl polyglycoside. EP-A-408 965 is also an older, but not prepublished application; it describes liquid detergents that include Contain alkyl glycoside, nonionic surfactants and optionally anionic surfactants.

Thickening alkyl glycoside compounds for liquid detergents are known from EP-A-199 765. There alkyl monoglycosides are described as viscosity regulators in detergents. According to the teaching of EP-A-199 765, suitable thickeners for liquid detergents are alkyl monoglycosides, which may contain a proportion of alkyl polyglycoside compounds with a degree of polymerization (DP) of 2 or more in such quantities that the average degree of polymerization of all alkyl glycoside compounds is lower than 1.4. The most effective compound judged to be thickening is an alkyl monoglycoside, the alkyl chain of which is branched and contains 13 carbon atoms. According to the teaching of EP-A-199 765, alkyl polyglycosides with a higher degree of polymerization than 1 and a linear alkyl chain are practically ineffective. It was therefore highly surprising to find that, contrary to the teaching of EP-A-199 765, alkyl glycoside compounds with a linear alkyl group with 8 to 20 carbon atoms and a degree of polymerization (DP) in the range from 1.35 to 2.50 already at a low concentration of 1.0 to 5.0% by weight on the detergent, in the presence of ethanol thickening substances in liquid detergents with a mixture of anionic surfactant and nonionic surfactant, in which the nonionic surfactant predominates. Preferred detergents of the type mentioned contain alkyl polyglycosides with a degree of polymerization in the range from 1.40 to 2.00, preferably from 1.40 to 1.60 and in particular at 1.4. Such alkyl polyglycosides are commercially available substances.

The object of the present invention is therefore to provide constituents which have a thickening action for liquid aqueous detergents and which in turn are wash-active. The present invention therefore relates to a liquid, aqueous detergent containing anionic and nonionic surfactants in which the proportion of nonionic surfactant predominates, and also containing alkylglycoside compounds as thickeners which are not taken into account when considering the ratio of nonionic surfactant to anionic surfactant are, and also containing ethanol in small amounts, characterized in that the alkyl glycoside compounds are alkyl polyglycosides with a linear alkyl group having 8 to 20 carbon atoms and with a degree of polymerization (DP) in the range from 1.35 to 2.50 and wherein the content of alkyl polyglycosides is in the range from 1.0 to 5.0% by weight, based on the detergent.

In addition to the textile detergents, detergents in the sense of the present invention also include shampoos, liquid hand detergents, dishwashing detergents and cosmetic preparations.

Anionic surfactants for the purposes of the present invention are alkylbenzenesulfonate or fatty alcohol sulfate or α-sulfofatty acid esters or mixtures of these surfactants. In addition, there are olefin sulfonates and paraffin sulfonates in question. Soap can also be used in amounts of up to 8% by weight, but is not included when considering the ratio of anionic surfactant to nonionic surfactant.

Balanced properties are those laundry detergents whose surfactant component contains, apart from the anionic surfactants already mentioned, nonionic surfactant of the type of the adducts of ethylene oxide with fatty alcohols. These are derived from saturated and / or unsaturated fatty alcohols with 10 to 20 carbon atoms in the molecule. The suitable fatty alcohol ethoxylates are obtained from these fatty alcohols by the addition of 1 to 20 moles of ethylene oxide to the fatty alcohol. According to the teaching of EP-A-199 765, the detergents described there may contain only a small proportion of fatty alcohol ethoxylates. It was therefore all the more surprising to find that detergents according to the invention with a surfactant component in which the proportion of nonionic surfactants of the fatty alcohol ethoxylate type predominates over the anionic surfactants have particularly balanced properties. When considering the ratio of nonionic to anionic surfactants, the alkyl polyglycosides are not included.

The detergents according to the invention have a pH in the range from 6.5 to 10, preferably in the range from 7 to 8. Because of the pH in the neutral range, the detergents according to the invention are particularly suitable for cleaning sensitive substrates.

While the anionic surfactant content in the detergents according to the invention is preferably in the range from 1 to 20% by weight, based on the total detergent, the nonionic surfactant content is 2 to 30% by weight, based on the total detergent. Detergents according to the invention in which the alkyl polyglycoside used as a thickener is an alkyl polyglucoside are preferred.

Examples

The following examples demonstrate the thickening effect of alkyl polyglucosides, which are derived from natural fatty alcohols of different lengths of the alkyl radical and which have different degrees of polymerization, in the presence of ethanol.

Different alkyl polyglucosides were incorporated in increasing concentration in a basic formulation for a liquid detergent, in which constant amounts of different anionic surfactants were used. The formulation was compensated by water. The basic recipe is as follows:
5.0 wt% anionic surfactant
12.0% by weight of C₁₂₋₁₈ fatty alcohol + 7 mol EO
1.25; 2.50; 5.00% by weight alkyl polyglucoside
6.0% by weight of tallow fatty acid soap, small amounts of ethanol, fragrances, dyes
Rest of water
The following were used as anionic surfactants:
Alkylbenzenesulfonate Na
C₁₂₋₁₈ fatty alcohol sulfate Na
α-Sulfotalgfatty acid methyl ester Na
The following alkyl polyglucosides were used in three different concentrations (1.25; 2.50; 5.00% by weight):
C₈₋₁₀ alkyl polyglucoside-1,6
C₉₋₁₁-alkyl polyglucoside-1,4
C₉₋₁₁ alkyl polyglucoside-1,6
C₁₂₋₁₄ alkyl polyglucoside 1.4
C₁₂₋₁₆ alkyl polyglucoside 1.6
At room temperature (25 ° C) the viscosity of the detergent was measured immediately after preparation and after three days. As a comparison, the viscosity of the detergents was measured without the addition of alkyl polyglucoside. The results are shown in Tables 1 to 3. Table 1 Detergent with alkylbenzenesulfonate Na Alkyl polyglucoside % By weight Viscosity (mPas) fresh after 3 days C₈₋₁₀-APG-1.6 - 93 95 " 1.25 122 124 " 2.50 141 150 " 5.00 168 178 C₉-C₁₁-APG-1.4 - 93 93 " 1.25 131 132 " 2.50 175 177 " 5.00 221 224 C₉₋₁₁-APG-1.6 - 93 93 1.25 125 128 2.50 158 175 5.00 228 227 C₁₂₋₁₄-APG-1.4 - 93 93 " 1.25 148 149 " 2.50 220 223 " 5.00 353 355 C₁₂₋₁₆-APG-1.6 - 93 93 " 1.25 140 145 " 2.50 213 215 " 5.00 356 355 Detergent with C₁₂₋₁₈ fatty alcohol sulfate Na Alkyl polyglucoside % By weight Viscosity (mPas) fresh after 3 days C₈₋₁₀-APG-1.6 - 45 48 " 1.25 57 55 " 2.50 69 69 " 5.00 104 105 C₉₋₁₁-APG-1.4 - 45 48 " 1.25 67 69 " 2.50 102 102 " 5.00 194 195 C₉₋₁₁-APG-1.6 - 45 48 " 1.25 60 68 " 2.50 87 85 " 5.00 159 160 C₁₂₋₁₄-APG-1.4 - 45 48 " 1.25 74 75 " 2.50 134 133 " 5.00 362 363 C₁₂₋₁₆-APG-1.6 - 45 48 " 1.25 72 74 " 2.50 119 122 " 5.00 343 345 Detergent with α-sulfotalg fatty acid methyl ester Na Alkyl polyglucoside % By weight Viscosity (mPas) fresh after 3 days C₈₋₁₀-APG-1.6 - 50 50 " 1.25 62 55 " 2.50 78 76 " 5.00 115 115 C₉₋₁₁-APG-1.4 - 50 50 " 1.25 78 78 " 2.50 112 112 " 5.00 222 225 C₉₋₁₁-APG-1.6 - 50 50 " 1.25 68 69 " 2.50 98 100 " 5.00 180 177 C₁₂₋₁₄-APG-1.4 - 50 50 " 1.25 85 82 " 2.50 159 160 " 5.00 438 440 C₁₂₋₁₆-APG-1.6 - 50 50 " 1.25 78 75 " 2.50 145 148 " 5.00 368 37

As can be seen from Tables 1 to 3, the thickening effect of the alkyl polyglucosides with a D.P. of over 1.35. The length of the alkyl group has an influence on the thickening effect, and the more carbon atoms the alkyl group has, the stronger the effect. As the concentration of alkyl polyglucoside increases, the viscosity also increases, while the degree of polymerization D.P. is apparently without any appreciable influence on the thickening effect of the alkyl polyglucosides, which was not to be expected.

Claims (8)

1. A liquid water-based detergent containing anionic and nonionic surfactants, in which the percentage content of nonionic surfactant predominates, and further containing alkyl glycoside compounds - which are not included in the ratio of nonionic surfactant to anionic surfactant - as thickeners and small quantities of ethanol, characterized in that the alkyl glycoside compounds are alkyl polyglycosides with a linear C₈₋₂₀ alkyl group and a degree of polymerization (D.P.) of 1.35 to 2.50, the alkyl polyglycoside content being from 1.0 to 5.0% by weight, based on the detergent.
2. A detergent as claimed in claim 1, characterized in that the degree of polymerization is from 1.40 to 2.00, preferably from 1.40 to 1.60 and more preferably 1.40.
3. A detergent as claimed in claim 1 or 2, characterized in that it contains alkyl benzenesulfonate, fatty alcohol sulfate, α-sulfofatty acid ester or mixtures of these surfactants as the anionic surfactant.
4. A detergent as claimed in any of claims 1 to 3, characterized in that, besides the alkyl polyglycosides, it contains adducts of ethylene oxide with fatty alcohols as the nonionic surfactant.
5. A detergent as claimed in any of claims 1 to 4, characterized in that the pH value of the detergent is in the range from 6.5 to 10 and preferably in the range from 7 to 8.
6. A detergent as claimed in any of claims 1 to 5, characterized in that it contains 1 to 20% by weight of anionic surfactant, based on the detergent as a whole.
7. A detergent as claimed in any of claims 1 to 6, characterized in that it contains 2 to 30% by weight of nonionic surfactant , based on the detergent as a whole.
8. A detergent as claimed in any of claims 1 to 7, characterized in that the alkyl polyglycoside is an alkyl polyglucoside.