EP2336280A1 - Use of branched alkyl (oligo)gycosides in cleaning agents - Google Patents

Abstract

Use of alkyl (oligo)glycoside (I) as a hydrotrope for an aqueous system, is claimed. Use of alkyl (oligo)glycoside of formula (R-O[G] x) (I) as a hydrotrope for an aqueous system, is claimed. G : glycoside; x : 1-3; and R : 2-propylheptyl. An independent claim is also included for a dishwashing agent comprising (I) and no more alkyl (oligo)glycoside with branched alkyl or alkenyl residues.

Description

The present invention relates to the use of certain branched alkyl (oligo) glycosides in detergents.

Alkyl (oligo) glycosides have long been known nonionic surfactants, which are used both in cosmetics but also in detergents and cleaners. The advantages of these surfactant classes are in particular their good biodegradability, but also the fact that these surfactants can be obtained from renewable raw materials. Alkyl and alkenyl oligoglycosides follow the formula R'O- [G] p in the R 'for an alkyl and / or alkenyl radical having 4 to 22 carbon atoms, G for a sugar radical having 5 or 6 carbon atoms and p for numbers from 1 to 10 stands. They can be obtained by the relevant methods of preparative organic chemistry. Representative of the extensive literature is here on the review of Biermann et al. in Starch / Strength 45, 281 (1993 ), such as J.Kahre et al. in SÖFW Journal Heft 8, 598 (1995 ). The alkyl and / or alkenyl oligoglycosides can be derived from aldoses or ketoses having 5 or 6 carbon atoms, preferably glucose. The preferred alkyl and / or alkenyl oligoglycosides are thus alkyl and / or alkenyl oligoglucosides. The index number p in the general formula (I) indicates the degree of oligomerization (DP), ie the distribution of mono- and oligoglycosides, and stands for a number between 1 and 10. While p in a given compound must always be an integer, and here especially If p = 1 to 6 can be assumed, the value p for a given alkyl (oligo) glycoside is an analytically determined arithmetic variable, which usually represents a fractional number. Preference is given to using alkyl and / or alkenyl oligoglycosides having an average degree of oligomerization p of from 1.1 to 3.0.

In addition to alkyl (oligo) glycosides based on unbranched fatty alcohols, such compounds are known which contain branched radicals R '. Already in the USH 171 alkyl (oligo) glycosides are disclosed, wherein the alcohol moiety may be branched in 2-position, and as branching, for example, an ethyl or propyl radical is disclosed. The document also discloses the suitability of such illustrated Alkyl (oligo) glycosides for detergents and cleaners. In the EP 0 690 868 A1 detergents are concretely disclosed wherein the agents contain branched alkyl (oligo) glycosides. Guerbet alcohols, and in particular 2-ethylhexyl alcohol and 2-propylheptyl alcohol, are mentioned as branched alcohols. In the EP 1 292 660 A1 describe single-phase microemulsions containing branched alkyl (oligo) glycosides.

However, it has now surprisingly been found that these branched alkyl (oligo) glycosides have special properties that make them interesting for a variety of applications.

bedeutet, worin R¹ für einen linearen Alkylrest mit 1 bis 6 C-Atomen steht, und R² einen Methyl- oder Ethylrest bedeuten und n Zahlen von 1 bis 10 annehmen kann als Hydrotop für wässerige Systeme.A first subject of the present application therefore relates to the use of alkyl (oligo) glycosides according to the general formula (I)

RO- [G] x (I)

where G is a glycoside radical, x is a number from 1 to 3 and R is a branched radical

in which R ^{1 is} a linear alkyl radical having 1 to 6 C atoms, and R ^{2 is} a methyl or ethyl radical and n can assume numbers from 1 to 10 as hydrotop for aqueous systems.

The compounds of the formula (I) are known. Their preparation is described for example in USH 171. Hydrotropy refers to the phenomenon that a sparingly soluble substance becomes water-soluble in the presence of a second component, which itself is not a solvent. Substances which cause such solubility improvement are termed hydrotropes or hydrotropes. They act as solubilizers with different mechanisms of action: substances that tend to form association colloids, such. As surfactants, z. By formation of micelles. B. allow the solubility of long-chain, otherwise water-insoluble alcohols. typical Hydrotrope, the z. B. used in the formulation of liquid detergents are xylene or cumene sulfonate. Other substances, eg. As urea or N-methylacetamide, increase the solubility by a structure-breaking effect, in which the water structure is degraded in the vicinity of the hydrophobic group of a poorly soluble substance. Finally, a solubility increase can also be brought about by the formation of mixed crystals with the hydrotropic substance in the bottom body of the component to be dissolved. Solutions of hydrotrope (hydrotrope solutions) are used instead of organic solvents for extraction purposes. Advantage: The solutions are non-volatile, non-flammable and non-toxic, can be easily regenerated and generally have higher HLB values. Particularly preferred is currently the cumene sulfonate, which, however, is not biodegradable.

For the purposes of the present teaching, alkyl (oligo) glycosides of the formula (I) are preferably selected in which R is a 2-Propyhlheptylrest.

The use of alkyl (oligo) glycosides of the formula (I) is preferably carried out in amounts of 0.5 to 10 wt .-%, preferably 1 to 5 wt .-% and in particular in amounts of 2 to 4 wt .-%, based on the watery system. As aqueous systems are both detergents and cleaners, but also cosmetic preparations in question. Aqueous systems within the meaning of the present technical teaching contain at least 50 wt .-% water and preferably 50 to 99 wt .-%, or in particular 65 to 95 wt .-% water. The alkyl (oligo) glycosides according to the formula (I) are preferably used as hydrotropes in cleaners and here preferably in aqueous all-purpose cleaners, dishwashing detergents and bath cleaners.

The use in dishwashing agents is particularly preferred since the alkyl (oligo) glycosides of the formula (I) have good compatibility with plastics and, in particular, the tendency for so-called crack corrosion is lower than for other nonionic surfactants.

The branched alkyl (oligo) glycosides of the present invention used in the present invention have comparable properties as the cumene sulfonate, however, they are better biodegradable and based on natural, renewable resources.

Examples 1. General preparation instructions for the synthesis of 2-propylheptyl glycosides:

In a 4-1 stirred reactor with stirrer, reflux condenser, water, distillate, vacuum stabilizer and vacuum pump, a mixture of the glucose used and the main amount of 2-propylheptyl was presented. After reaching the reaction temperature, the catalyst dissolved in a portion of the alcohol used was metered into the reaction mixture within 0.5 h. The water obtained in the course of the reaction was continuously distilled off and collected via the water separator in the distillate receiver. The reaction was over when no more water of reaction was obtained. The acidic catalyst in the reaction mixture was neutralized with magnesium oxide and 50% NaOH solution. The content of excess alcohol was separated in a conventional manner at elevated temperature and reduced pressure (180 ° C, <1 mbar). Subsequently, the propylheptylglucoside was diluted with water to a paste having a solids concentration of 65-75%. This aqueous solution was bleached at 90 ° C with the addition of hydrogen peroxide (35%) and sodium hydroxide solution (20%) to a Hazen color number <50. The Hazen color number was determined using the colorimeter Lico 300 from Dr. Ing. Long measured. For measurement, the glucoside solution is diluted to 10% active substance and filtered through a 0.45μ filter into an 11 mm round cuvette. The following 3 products according to the invention were prepared according to the general procedure, and a 2-ethylhexyl glycoside for comparison:

example 1

1812.60 g 2-propylheptanol (11.45 mol) 629.80 g Glucose monohydrate (3.18 mol) 3.81 g Sulfosuccinic acid 70% (0.013 mol) 0.71 g magnesia 1.78 g Caustic soda (50%) Reaction temperature: 110 ° C Print: 30 mbar DP degree: 1.39 Active substance content of the aqueous paste: 65.4% by weight

Example 2

2036.60 g 2-propylheptanol (12.87 mol) 536.10 g Xylose (3.57 mol) 8.60 g Dodecylbenzenesulfonic acid (0.0275 mol) 0.71 g magnesia 1.84 g Caustic soda (50%) Reaction temperature: 102 ° C Print: 30 mbar DP degree: 1.24 Active substance content of the aqueous paste: wt% 66.4%

Example 3

1421.8 g 2-propylheptanol (8.98 mol) 889.2 g Glucose monohydrate (4.49 mol) 7.70 g Dodecylbenzenesulfonic acid (0.0246 mol) 0.71 g magnesia 2.20 g Caustic soda (50%) Reaction temperature: 110 ° C Print: 30 mbar DP degree: 1.81 Active substance content of the aqueous paste: Weight% 58.7%

Example 4 (comparison)

1172.1 g 2-ethylhexanol (9 mol) 540.5 g Glucose anhydrous (3 mol) 7.70 g Dodecylbenzenesulfonic acid (0.0177 mol) 0.28 g magnesia 1.13 g Caustic soda (50%) Reaction temperature: 100 ° C Print: 40 mbar DP degree: 1.51 Active substance content of the aqueous paste: 49.4% by weight

2 Application engineering investigations 2.1 foaming behavior:

With the help of a Schaummeßapparatur the intrinsic foam behavior of Propylheptylglucoside and three other alkylpolyglucosides was tested in comparison. The foam device enables a dynamic "Ross-Miles" test. The surfactant liquid is continuously pumped in the circulation and pumped to the liquid level. In this method, the intrinsic foam behavior of active substances or formulations is tested as a function of the temperature. For solid samples always prepare a preliminary solution, unless the dissolution behavior is investigated. 500mL dist. Water is poured into the double-walled 2 liter graduated cylinder of the free-fall circuit apparatus. In the thermostat, the desired temperature profile (8 ° C to 80 ° C in 45 minutes) is opened and tempered to the corresponding start temperature ± 1 ° C in the measuring cylinder.

As soon as the start temperature has been reached, the temperature profile and the peristaltic pump are started. At the same time, 0.2 ml of the test substance or formulation with 0.2 ml of active substance is pipetted into the water pumped in the circulation. In addition, the stopwatch is to start. The resulting total volume (foam and liquid) is recorded with the associated temperatures and times. The recording of the measured values in areas with rapid foam height change takes place at short intervals in order to reproduce the course more accurately.

The result of the temperature-dependent foam height is for 4 alkyl polyglucosides in illustration 1 been presented. Here, a C8 / 10 fatty alcohol glucoside (Glucopon 225 DK), a C12 / 14 fatty alcohol glucoside (Glucopon 600 UP), a 2-ethylhexyl glucoside (Berol AG 6202, Akzo Nobel) and the APG from Example 1 were tested.

One recognizes in the illustration 1 It is clear that the linear fatty alcohol-based APGs in the measurement arrangement are highly foaming surfactants, since the maximum foam height of 200 ml is achieved. The longer C12 / 14 chain length of the fatty alcohol foams over the entire temperature range, the short C8 / 10 linear chain slowly becomes low-foaming at 35 ° C. Only at about 50 ° C, the foam for an industrial cleaning application in an acceptable height.

The branched 2-ethylhexyl APG shows a low foam height over the entire temperature range. The APG based on propylheptanol from Example 1 shows a similar foaming behavior over the entire temperature range. The low foaming capacity is comparable to 2-ethylhexyl APG.

Foam quality:

Product Examples 2, 3 and 4 were tested to improve the properties of surfactant formulations in view of the above requirements.

• 9%* Texapon NSO
• 3%* Dehyton PK 45
• 2%* zu prüfende Substanz
• auf 100 dest. Wasser

Test formulation:

• 9% * Texapon NSO
• 3% * Dehyton PK 45
• 2% * substance to be tested
• to 100 dist. water

Procedure: Texapon NSO, Dehyton PK 45 and the substance to be tested are weighed in succession, to 100 g with dist. Water filled and mixed. Optionally, the pH is adjusted with citric acid. From this formulation, a 2.5% solution is prepared using hard water (15 ° dH). This is then whipped in a 800ml beaker with a mizer disk for 10s at 2000 revolutions. For this purpose, the stirrer is operated for 10 s at 2000 revolutions. The foam is spooned onto a Ceran plate and photographed using a spatula spoon. For foam evaluation, the height of the foam in the beaker is measured and the foam quality is rated 1-6 grades based on the benchmarks listed below, where 1 stands for the best and 6 for the worst foam quality. Table 3 shows the foam heights for 4 different APGs: <u> Table 3 </ u> 9% * Texapon NSO + 3% Dehyton PK45 foam height foam quality + --- 6.5 cm 4-5 + 2% * propylheptylxyloside (Ex. 2) 10.0 cm 1 - 2 + 2% * propylheptyl glucoside (Ex. 3) 9.5 cm 1 - 2 + 2% * ethylhexyl glucoside (Ex. 4) 6.0 cm 2 - 3 + 2% * Plantacare 1200 UP 5.5 cm 3 - 4 * based on active substance (AS)

As the examples in Table 3 show, the foam height or the foam structure of surfactant-containing formulations is greatly improved by the addition of propylheptyl glycosides. The comparative examples with the ethyhexyl glucoside and the Plantacare 1200 UP show that other alkylpolyglycosides show these properties to a much lesser extent.

2.2 Determination of the cleaning performance of the alkylpolyglucosides investigated:

The cleaning performance of the investigated APGs was carried out using a modified and automated Gardner test. The main features of the test method were published as an IPP quality standard in SÖFW 112. 10/1986 (Gardner test). The method is based on wiping a test soil treated white soil carrier under defined conditions with a sponge soaked in the test material. The cleaning effect is measured by means of digital image evaluation against the untreated dirt carrier. For better comparability, all the glucosides were neutralized so that the test measured only the cleaning performance of the surfactant and not in the presence of alkali. Table 4 shows the cleaning performance of the investigated 4 APGs: Component to 1% by weight (AS) Measured cleaning performance in% Linear C8 / 10 fatty alcohol glucoside, neutralized 68 Linear C12 / 14 fatty alcohol glucoside, neutralized 61 2-ethylhexyl glucoside, neutralized 55 Glucoside from Example 1, Propylheptylglucosid neutralized 90

It can be clearly seen that the linear fatty alcohol glucosides have a good cleaning performance. The 2-Ethylhexylglucosid has the worst cleaning performance in this Messanordung. The Propylheptylglucosid invention shows a significantly better cleaning performance than the comparison products.

2.3. Hydrotropiemessungen

In industrial cleaning processes, especially in alkaline applications, alkyl polyglucosides are used as solubilizers in order to formulate foam-controlling surfactants into cleaning formulations, ie to obtain a homogeneous cleaning solution. However, the foam-controlling surfactants are generally difficult to formulate into aqueous systems because of their hydrophobicity. Table 5 indicates how much hydrotrope (= solubilizer) has to be added in order to obtain the components presented clearly and homogeneously.
Batch 1: 75% by weight of water, 10% by weight of NaOH, 10% of NTA (nitrilotriacetic acid), 5% by weight of Dehypon LS 54
Approach 2: 75% by weight of water, 10% by weight of NaOH, 15% by weight of Dehypon LS 36 <u> Table 5: </ u> component Add% by weight (AS) to batch 1 Add% by weight (AS) to batch 2 sodium cumene 10 15 C8 / 10 FA glucoside 25, then solution still cloudy 35 2-ethylhexyl glucoside 15 25 Propylheptylglucosid 16 18 AS = active substance

In the alkaline formulation with much hydrophobic surfactant, the propylheptyl glucoside shows significantly better solubilizing properties than the linear fatty alcohol glucoside and the 2-ethylhexyl glucoside

2.4 Plastic Compatibility

Here the stress corrosion cracking of the materials is investigated. Stress corrosion cracking test on plastic rods in accordance with DIN 53449 T 1-3. The method was described in SÖFW 130 10-2004 p.83-93.

A stainless steel pin is pressed vertically into the drilled plastic test strips with a hole. The test strips are then immersed briefly in the medium to be tested. Adherent solution will not be removed. The dipping process is repeated after 24 hours and a total of 5 times. Every 24 hours the test rod is evaluated. evaluation 0-7d 0-14d 1 no attack -> recommendable recommendable 2 slight cracks -> conditionally suitable suitable 3 continuous crack -> conditionally suitable conditionally suitable 4 breached -> conditionally suitable conditionally suitable

In the test, the most critical substrates were selected. Table 6 shows the results: <u> Table 6 </ u> PMMA PC SECTION Plexiglass 8 N Makrolon 3103 Terez 3010 7d 14d 7d 14d 7d 14d Propylheptylglucosid 1 1 1 1.5 1 1 C8 / 10 fatty alcohol glucoside, linear 1 1 1 1 1 1 Fettalkoholethoxylat 3 4 3 3 3 3 2-ethylhexyl glucoside 1 1.5 2 2.75 2 2

It can be seen here that the linear and the propylheptylglucoside have the best material compatibility and are therefore suitable for use on these surfaces. The fatty alcohol ethoxylate and the 2-ethylhexyl glucoside show no good material compatibility.

Claims (4)

Use of alkyl (oligo) glycosides according to the general formula (I)

RO- [G] x (I)

where G is a glycoside radical, x is a number from 1 to 3 and R is a branched radical

in which R ^{1 is} a linear alkyl radical having 1 to 6 C atoms, and R ^{2 is} a methyl or ethyl radical and n can assume numbers from 1 to 10 as hydrotop for aqueous systems. Use according to claim 1, characterized in that alkyl (oligo) glycosides of the formula (I) are selected in which R is a 2-Propyhlheptylrest. Use according to at least one of claims 1 to 2, characterized in that the alkyl (oligo) glycosides of the formula (I) in amounts of 0.5 to 10 wt .-%, preferably 1 to 5 wt .-% and in particular in amounts from 2 to 4 wt .-%, based on the aqueous system can be used. Use according to at least one of claims 1 to 3, characterized in that the alkyl (oligo) glycosides of the formula (I) are used in aqueous detergents or cleaners, or in aqueous cosmetic compositions as hydrotropes, preferably in dishwashing detergents.

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