EP0670877B1 - Viscous aqueous surfactant preparations - Google Patents

Abstract

The invention concerns dilute aqueous formulations containing 2 to 10 % by wt. of an alkyl glycoside of the formula R1-O(G)n in which R1 is an alkyl residue with 8 to 22 C-atoms, G is a glycose unit and n is a number between 1 and 10. The aim of the invention is improve the ease to handling of such formulations under the conditions of use while reducing the content of non-alkyl-glycosidic active substance in the formulation to the minimum. This is achieved essentially by the addition, to increase the viscosity, of 0.05 to 2 % by wt. of an ether sulphate of the formula R2-O-(CpH2pO)qSO3X in which R2 is an alkyl or alkenyl residue with 8 to 22 C-atoms and up to 3 C-C double bonds, p is the number 2 or 3, q is a number from 1 to 10 and X is an alkali-metal ion, an ammonium ion or an alkyl-substituted or hydroxyalkyl-substituted ammonium ion, the ratio by weight of alkyl glycoside to ether sulphate being 35:1 to 3:1.

Description

The invention relates to low-concentration and highly viscous aqueous surfactant preparations which contain alkyl glycosides and certain alkyl or alkenyl ether sulfates, a process for their preparation and the use of such preparations as washing or cleaning agents.

It has long been known that alkyl glycosides with long-chain alkyl groups belong to the nonionic surfactants. The person skilled in the art also knows, for example in A.M. Schwartz, J.W. Perry, Surface Active Agents, Vol. I, Interscience Publishers, 1949, page 372 described that surfactant mixtures generally have synergistic effects and often have better cleaning properties than would result from the sum of the values of the individual components.

Detergents which contain alkyl glycosides in combination with at least one conventional anionic surfactant in a ratio of 1:10 to 10: 1 are described in European patent application EP 070 074. Detergents which contain alkyl glycosides and anionic surfactants are also known from European patent application EP 092 877. Furthermore, liquid detergents are known from European patent application EP 105 556, which contain alkyl glycosides, certain other nonionic surfactants and anionic surfactants. From the international patent application WO 86/02943 alkylglycoside-containing liquid detergents are known which contain conventional anionic surfactants. A process for the production of alkyl glycosides using catalytic amounts of an anionic surfactant in its acid form is known from European patent application EP 132 043. In European patent application EP 132 046 it is proposed to modify such a manufacturing process by adding certain bases after the actual reaction to neutralize the catalyst. The intermediate detergents or cleaning products mentioned in these documents based on alkylglycoside are relatively highly concentrated aqueous solutions or pastes, since the components provided for the mixture to form finished compositions should have the highest possible active substance content. At the same time, they must be easy to handle, which means that they should have the lowest possible viscosity, flow and be easy to pump. In contrast, the requirement for a certain minimum viscosity is placed on aqueous liquid products used by the consumer, which include in particular liquid detergents, dishwashing detergents and universal cleaners, but also cosmetic products, for example hair shampoos or body cleaning lotions, although the active substance content of such products is generally relatively low. Products of this type therefore normally contain thickeners, which generally have the disadvantage that they themselves do not contribute to the cleaning performance of the surfactant component contained in the agents. Typical thickeners are inorganic water-soluble salts, in particular sodium chloride, and salts of non-surface-active aromatic sulfonic acids, for example sodium cumene sulfonate.

Organic thickeners are usually fatty acid alkanolamides, such as coconut fatty acid monoethanolamide, lauric acid monoethanolamide, oleic acid diethanolamide and coconut fatty acid diethanolamide, polyethylene glycol difatty acid esters and a number of water-soluble polymers.

In most cases it is not possible or only possible to use high concentrations to build up the desired viscosity in the surfactant solution simply by using inorganic salts. It is therefore usually necessary to use organic thickeners in addition to the inorganic salts, which have a number of disadvantages. For example, solutions thickened with polyethylene glycol fatty acid diesters often have inadequate viscosity stability during storage, while water-soluble polymers often dissolve only with difficulty and cause undesirable flow behavior.

In European patent application EP 306 843 it is proposed to use adducts of ethylene oxide and / or propylene oxide with unsaturated fatty alcohols to thicken surfactant solutions. These products no longer have the disadvantages mentioned above; however, there is still a need for thickeners with comparable properties with an increased thickening effect. For a given content of thickeners, this would enable the production of systems with a higher viscosity as well as a reduction in the content of thickeners at a given viscosity.

From European patent application EP 486 784 it is known that agents which contain 15% by weight alkyl glycoside have a viscosity of less than 350 mPa.s at a content of approx. 0.5% by weight alkyl ether sulfate and the viscosity of such Agent goes through a minimum with the addition of increasing amounts of alkyl ether sulfate. For aqueous liquid products used by the consumer, such agents are generally both too highly concentrated and not viscous enough to be regarded as easy to handle.

Surprisingly, it has now been found that, in contrast, significantly lower alkyl glycoside concentrations, the addition of certain ether sulfates results in a strongly pronounced viscosity maximum and a storage-stable, liquid, flowable alkyl glycoside preparation can be obtained on an aqueous basis, which due to its relatively high viscosity at a relatively low concentration has easy handling under conditions of use and contains the smallest possible amounts of non-alkyl glycosidic active substance if alkyl glycoside and certain alkyl or alkenyl ether sulfate are mixed in certain proportions.

• 2 Gew.-% bis 10 Gew.-% eines Alkylglykosids der Formel I,
  
          R¹-O(G)_n     (I)
  
  in der R¹ einen Alkylrest mit 8 bis 22 C-Atomen, G eine Glykose-Einheit und n eine Zahl zwischen 1 und 10 bedeuten,
• 0,05 Gew.-% bis 2 Gew.-% eines Ethersulfats der Formel II,
  
          R²-O-(C_pH_2pO)_qSO₃X     (II)
  
  in der R² einen Alkyl- oder Alkenylrest mit 8 bis 22 C-Atomen und bis zu 3 C-C-Doppelbindungen, p die Zahl 2 oder 3, q eine Zahl von 1 bis 10, vorzugsweise von 1 bis 5, und X ein Alkalimetallion, ein Ammonium- oder alkyl- bzw. hydroxyalkylsubstituiertes Ammoniumion bedeuten,
• wobei das Gewichtsverhältnis von Alkylglykosid gemäß Formel I zu Ethersulfat gemäß Formel II 35 : 1 bis 3 : 1, vorzugsweise 15:1 bis 8:1 beträgt,
• und auf 100 Gew.-% Wasser oder eines Gemischs aus Wasser mit einem wassermischbaren organischen Lösungsmittel bestehen.

The surfactant preparations according to the invention are accordingly gel-like aqueous mixtures which essentially consist of

• 2% by weight to 10% by weight of an alkyl glycoside of the formula I,
  
  R ¹ -O (G) _n (I)
  
  in which R ^{1 is} an alkyl radical having 8 to 22 carbon atoms, G is a glycose unit and n is a number between 1 and 10,
• 0.05% by weight to 2% by weight of an ether sulfate of the formula II,
  
  R ² -O- (C _p H _2p O) _q SO ₃ X (II)
  
  in which R ^{2 is} an alkyl or alkenyl radical having 8 to 22 carbon atoms and up to 3 CC double bonds, p is the number 2 or 3, q is a number from 1 to 10, preferably from 1 to 5, and X is an alkali metal ion, is an ammonium or alkyl- or hydroxyalkyl-substituted ammonium ion,
• wherein the weight ratio of alkyl glycoside according to formula I to ether sulfate according to formula II is 35: 1 to 3: 1, preferably 15: 1 to 8: 1,
• and insist on 100% by weight of water or a mixture of water with a water-miscible organic solvent.

In the context of the present invention, gel-like preparations are understood to be structured, isotropic, viscoelastic solutions with a viscoelastic network structure constructed from rod micelles. They preferably have a viscosity, measured at a temperature in the range from 20 ° C. to 25 ° C. at a shear rate of 10 s ⁻¹ , from 400 mPas to 10,000 mPas, in particular from 500 mPas to 8,000 mPa · s.

The alkyl glycoside preparations according to the invention preferably contain 3% by weight to 9% by weight, in particular 4% by weight to 8% by weight of alkyl glycoside according to formula I, 0.1% by weight to 2% by weight of ether sulfate according to formula II and to 100 wt .-% water. A portion of the water, in particular not more than 5% by weight, based on the preparation according to the invention, can be mixed with a water-miscible organic solvent, preferably from the group comprising alcohols with 1 to 4 carbon atoms, glycols with 2 to 4 carbon atoms and which contain di- and triglycols derived from these as well as the corresponding glycol ethers and mixtures of these substances.

Another object of the invention is a process for the preparation of storage-stable, gel-like surfactant preparations on an aqueous basis which have a viscosity in the range of 400 mPa at a temperature in the range from 20 ° C. to 25 ° C. at a shear rate of 10 s ^-1 . s to 10,000 mPa.s, by mixing an aqueous solution containing an alkyl glycoside of the formula I,

R ¹ -O (G) _n (I)

in which R ^{1 is} an alkyl radical having 8 to 22 carbon atoms, G is a glycose unit and n is a number between 1 and 10, with an ether sulfate of the formula II,

R ² -O- (C _p H _2p O) _q SO ₃ X (II)

in which R ^{2 is} an alkyl or alkenyl radical having 8 to 22 carbon atoms and up to 3 CC double bonds, p is the number 2 or 3, q is a number from 1 to 10, and X is an alkali metal ion, an ammonium or alkyl or hydroxyalkyl-substituted ammonium ion,
in the weight ratio of alkyl glycoside according to formula I to ether sulfate according to formula II from 35: 1 to 3: 1, and with so much water or a mixture of water with a water-miscible organic solvent that the total surfactant content in the preparation is 2.2% by weight is up to 12% by weight.

The procedure is preferably such that an aqueous paste which contains alkyl glycoside of the formula I in a concentration of 30% by weight to 60% by weight is mixed in such an amount with the ether sulfate or with an aqueous solution of the ether sulfate, that the sum of the surfactants in the resulting aqueous preparation is 2.5% by weight to 10% by weight and the resulting gel contains 90% by weight to 97.5% by weight of water. In principle, the water can be mixed in at any point in the preparation of the agents according to the invention if the starting materials used do not already contain sufficient such solvent. Preferably the Components heated to temperatures from 60 ° C to 80 ° C and mixed with conventional mixers, which are preferably heated and are kept during the entire mixing process, in particular at temperatures in the range mentioned.

The alkyl glycosides suitable for the surfactant preparations according to the invention and their preparation are described, for example, in European patent applications EP 92 355, EP 301 298, EP 357 969 and EP 362 671 or the US Pat. No. 3,547,828. The glycoside components ((G) _n in formula I) of such alkyl glycosides are oligomers or polymers from naturally occurring aldose or ketose monomers, in particular glucose, mannose, fructose, galactose, talose, gulose, altrose, allose , Idose, ribose, arabinose, xylose and lyxose. The oligomers consisting of such glycosidically linked monomers are characterized not only by the type of sugar they contain, but also by their number, the so-called degree of oligomerization. The degree of oligomerization (n in formula I) can also take non-integer numerical values as the quantity to be determined analytically; it is generally between 1 and 10, for the alkyl glycosides preferably used below 1.5, in particular between 1.2 and 1.4. The preferred monomer building block is glucose because of its good availability.

The alkyl part (R ¹ in formula I) of the alkyl glycosides contained in the surfactant preparations according to the invention preferably also originates from easily accessible derivatives of renewable raw materials, in particular from fatty alcohols, although their branched chain isomers, in particular so-called oxo alcohols, can also be used to prepare usable alkyl glycosides. Accordingly, the primary alcohols with linear octyl, decyl, dodecyl, tetradecyl, hexadecyl or octadecyl radicals and mixtures thereof are particularly useful. Particularly suitable alkyl glycosides contain a coconut fatty alkyl radical, ie mixtures with essentially R ¹ = dodecyl and R ¹ = tetradecyl.

The alkyl glycosides may contain small amounts, for example 1 to 2%, of unreacted free fatty alcohol, which generally does not have a disadvantageous effect on the properties of the preparations produced therewith.

The ether sulfates which can be used in the context of the invention are anionic surfactants which are generally obtained by the known reaction of aliphatic primary alcohols with preferably 1 to 10, in particular 1 to 5 mol equivalents of alkylene oxide, in particular ethylene oxide, and subsequent reaction with a sulfating agent, for example sulfur trioxide or chlorosulfonic acid , and subsequent neutralization and hydrolysis of the reaction products formed, preferably with alkali, ammonium or alkyl or hydroxyalkyl-substituted ammonium bases. Ether sulfates to which the process according to the invention extends are preferably derived from alkoxylated, in particular ethoxylated, fatty alcohols having 12 to 22 carbon atoms, in particular 12 to 18 carbon atoms. In these, the degree of alkoxylation (q in formula II) is preferably 1 to 3. The degree of alkoxylation as a quantity to be determined analytically can also assume non-integer numerical values. Typical examples of starting materials for the ether sulfates which can be used according to the invention are lauryl alcohol, myristyl alcohol, cetyl alcohol, stearyl alcohol or behenyl alcohol and the corresponding unsaturated alcohols which can be obtained by reducing the carboxyl group from oleic acid, lauroleic acid, myristoleic acid, gadoleic acid, erucic acid, linoleic acid and linolenic acid. The ether sulfates can also be derived from technical alcohol mixtures, such as those obtained in the hydrogenation of technical fatty acid ester mixtures of natural origin or from aldehydes from Roelen's oxosynthesis.

The ether sulfates produced in this way preferably contain as little as possible, in particular not more than 5% by weight, based on ether sulfate, of inorganic salt. These include the alkali chlorides and especially the alkali sulfates. If salt contents in such low amounts do not already occur in the preparation of the ether sulfates described above, the ether sulfate can be brought to levels not exceeding 5% by weight, in particular from 0.1% by weight to 1.5% by weight, based in each case on ether sulfate, of inorganic salt by known methods, for example by recrystallization. It is extremely surprising that surfactant preparations according to the invention, which contain such low-salt ether sulfate, show a more pronounced, advantageous viscosity behavior in comparison to surfactant preparations containing higher-salt ether sulfate, although the addition of inorganic salts, in particular sodium chloride, is usually considered to be thickening.

Ether sulfates have long been known to be good anionic surfactants. It was surprising, however, that the viscosity of dilute aqueous alkyl glycoside solutions can be significantly increased by adding very small amounts of such anionic surfactants. In contrast, the addition of alkylbenzenesulfonate as an example of another anionic surfactant, which is also known to have high cleaning performance, reduces the viscosity of dilute aqueous alkylglycoside solutions.

The surfactant preparations according to the invention have excellent cleaning properties and high solubility in cold water. They are therefore preferably used as washing, rinsing or cleaning agents and in hair and body care or serve as storage-stable, easy-to-use premixes for the production of such agents. This includes the addition of other constituents customary in such agents, to which in particular builder substances, such as zeolites and layered silicates, corrosion inhibitors, bleaching agents, bleach activators, optical brighteners, enzymes, graying inhibitors, antimicrobial active ingredients, abrasives, foam stabilizers, preservatives, pH regulators, and turbidity Pearlescent agents, dyes and fragrances and additional surfactants are possible among the preparations according to the invention.

Examples example 1

Aqueous mixtures of the mixtures of ether sulfate given in Table 1 (sum of surfactant components 5% by weight), Table 2 (sum of surfactant components 7.5% by weight) and Table 3 (sum of surfactant components 10% by weight) ( C _12/14 alcohol, reacted with 2 mol equivalents of ethylene oxide and sulfated, sodium salt; containing approx. 1% by weight of inorganic salt sodium sulfate and chloride) with C _12/14 alkyl glucoside (degree of oligomerization 1.4) in the specified mixing ratios ( Alkyl glycoside to ether sulfate) had the viscosities listed below (25 ° C, measured with a shear stress-controlled rotation rheometer Carri-Med ^(R) CS 100 at a shear rate of 10 s ^-1 ), whereby for comparison also the values for equally concentrated ether sulfate-free aqueous Solutions are listed. Table 1: Properties of 5% by weight preparations (25 ° C) Mixing ratio [% by weight] Viscosity [mPa.s] 5-0 320 4.5: 0.5 500 4.75: 0.25 1400 Properties of 7.5 percent by weight preparations (25 ° C) Mixing ratio [% by weight] Viscosity [mPa.s] 7.5: 0 520 6.5: 1 1400 7: 0.5 2900 7.25: 0.25 1200 Properties of 10% by weight preparations (25 ° C) Mixing ratio [% by weight] Viscosity [mPa.s] 10: 0 720 8: 2 900 8.5: 1.5 4700 9: 1 7000 9.5: 0.5 2100

For comparison, preparations according to the invention were prepared and tested which contained C _12/14 alkyl glucoside and Na C _11/13 alkyl benzene sulfonate (Maranil ^(R) , manufacturer Hüls). These had a viscosity of 270 mPa · s in 5% by weight solution (weight ratio 4.9: 0.1) and a viscosity of 360 mPa · s in 10% by weight solution (weight ratio 9: 1).

In comparison to the more concentrated solutions known from EP 486 784, the preparations according to the invention have significantly higher viscosities.

Claims (11)

1. A viscous surfactant preparation of low concentration in the form of a gel-like water-containing mixture consisting essentially of

   2% by weight to 10% by weight of an alkyl glycoside corresponding to formula I:
   
           R¹-O(G)_n     (I)
   
   in which R¹ is an alkyl radical containing 8 to 22 carbon atoms, G is a glycose unit and n is a number of 1 to 10,

   0.05% by weight to 2% by weight of an ether sulfate corresponding to formula II:
   
           R²-O-(C_pH_2pO)_qSO₃X     (II)
   
   in which R² is an alkyl or alkenyl radical containing 8 to 22 carbon atoms and up to 3 C-C double bonds, p is the number 2 or 3, q is a number of 1 to 10 and X is an alkali metal ion, an ammonium or alkyl- or hydroxyalkyl-substituted ammonium ion,

   the ratio by weight of alkyl glycoside corresponding to formula I to ether sulfate corresponding to formula II being 35:1 to 3:1 and preferably 15:1 to 8:1, and

   water or a mixture of water with a water-miscible organic solvent to 100% by weight.
2. A surfactant preparation as claimed in claim 1, characterized in that it has a viscosity, measured at a temperature of 20°C to 25°C and at a shear rate of 10 s^-1, in the range from 400 mPa·s to 10,000 mPa·s and more particularly in the range from 500 mPa·s to 8,000 mPa·s.
3. A surfactant preparation as claimed in claim 1 or 2, characterized in that it contains 3% by weight to 9% by weight and, more particularly, 4% by weight to 8% by weight of alkyl glycoside corresponding to formula 1, 0.1% by weight to 2% by weight of ether sulfate corresponding to formula II and water or a mixture of water with no more than 5% by weight, based on the preparation according to the invention, of a water-miscible organic solvent to 100% by weight.
4. A surfactant preparation as claimed in any of claims 1 to 3, characterized in that the ether sulfate is a compound corresponding to formula II, in which R² is an alkyl radical containing 12 to 18 carbon atoms, p is the number 2 and q is a number of 1 to 10, and, more particularly, a number of 1 to 5.
5. A surfactant preparation as claimed in any of claims 1 to 4, characterized in that the ether sulfate used contains no more than 5% by weight and, more particularly, from 0.1% by weight to 1.5% by weight of inorganic salt.
6. A surfactant preparation as claimed in any of claims 1 to 5, characterized in that the alkyl glycoside corresponding to formula I has a degree of oligomerization n below 1.5 and, more particularly, between 1.2 and 1.4.
7. A process for the production of storable, gel-like water-based surfactant preparations which have a viscosity of 400 mPa·s to 10,000 mPa·s at a temperature of 20°C to 25°C by mixing an aqueous solution containing an alkyl glycoside corresponding to formula I:
   
           R¹-O(G)_n     (I)
   
   in which R¹ is an alkyl radical containing 8 to 22 carbon atoms, G is a glycose unit and n is a number of 1 to 10,
   with an ether sulfate corresponding to formula II:
   
           R²-O-(C_pH_2pO)_qSO₃X     (II)
   
   in which R² is an alkyl or alkenyl radical containing 8 to 22 carbon atoms and up to 3 C-C double bonds, p is the number 2 or 3, q is a number of 1 to 10 and X is an alkali metal ion, an ammonium or alkyl- or hydroxyalkyl-substituted ammonium ion,
   in a ratio by weight of alkyl glycoside corresponding to formula I to ether sulfate corresponding to formula II of 35:1 to 3:1 and with water or a mixture of water with a water-miscible organic solvent in such a quantity that the total surfactant content of the preparation is from 2.2% by weight to 12% by weight.
8. A process as claimed in claim 7, characterized in that an aqueous paste containing alkyl glycoside corresponding to formula I in a concentration of 30% by weight to 60% by weight is mixed with the ether sulfate corresponding to formula II or an aqueous solution of the ether sulfate in such a quantity that the sum total of surfactants in the resulting aqueous preparation is 2.5% by weight to 10% by weight and the resulting gel contains 90% by weight to 97.5% by weight of water.
9. A process as claimed in claim 7 or 8, characterized in that the components alkyl glycoside and ether sulfate are heated to temperatures of 60°C to 80°C and are mixed in a heatable mixer which is kept at temperatures in the range mentioned throughout the mixing process.
10. The use of the surfactant preparation claimed in any of claims 1 to 6 as a laundry detergent, dishwashing detergent, cleaning formulation, hair-care formulation or body-care formulation.
11. The use of the surfactant preparation claimed in any of claims 1 to 6 as a storable and easy-to-handle compound for the production of laundry detergents, dishwashing detergents, cleaning formulations, hair-care formulations or body-care formulations.