EP0486784A2 - Liquid foaming detergent of increased viscosity - Google Patents

Abstract

Conventional liquid dishwashing agents are predominantly produced on a petrochemical basis and have the disadvantage of incomplete biodegradability. A liquid, foaming detergent which has all the beneficial properties of conventional dishwashing agents while, at the same time, being well tolerated by skin and very environmentally compatible is now proposed. The surfactant ingredients are 5 - 40 % alkyl polyglycoside and 0.1 - 2.9 % anionic surfactant and 0 - 3 % other surfactants.

Description

The invention relates to an environmentally friendly, foaming, liquid cleaning agent.

Liquid, foaming cleaning agents aim at the manual cleaning of hard surfaces, especially in the household, such as. B. ceramics, porcelain, glass, metal and plastic. The most important area of application are manual dishwashing detergents for cleaning dishes.

Modern products here consist of neutral aqueous formulations based on highly foaming surfactants. The main components are sulfonates, such as. B. alkylbenzenesulfonates or sec-alkanesulfonates, both combined with fatty alcohol ether sulfates or fatty alcohol sulfates (EP-A-0 112 047). Small amounts of fatty acid alkanolamides and, more rarely, oxyethylates are added. Other common ingredients are solubilizers, colors and fragrances, preservatives etc.

The rinsing process usually takes place at a slightly elevated temperature (30 to 50 ° C) in dilute solutions. Of particular importance, because of the long skin contact of the user, the skin compatibility of the detergent. When the consumer assesses the cleaning power, the foaming power of the solution plays a significant role, for example in the sense that the longer the cleaning solution foams during the rinsing process, the greater its cleaning power.

Another important consumer property of the cleaning liquid is the flow behavior. Too high and too low viscosities make manual dosing of the cleaning concentrate difficult. Very low viscosities also lead to the impression of a low active substance content. Average viscosities between 150 and 300 mPa · s at shear rates of approx. 10 sec⁻¹ are ideal for household products. Another important property is the compatibility of the active ingredients with drinking water; clear solutions are desirable.

The currently customary cleaning agents usually show sufficient cleaning action and a high foaming power, suitable flow behavior and sufficient compatibility with the hardness constituents of the water. In contrast, these mixtures have a low skin-friendliness, since their essential components - namely the anionic surfactants of the sulfonate or sulfate type - are highly irritating to the skin.

Another serious disadvantage with regard to the scarcity of raw material reserves is the predominantly petrochemical basis of the anionic surfactants mentioned, combined with incomplete biodegradability.

The object of the invention was therefore to provide a cleaning agent which implies all the desired properties, with high skin tolerance and excellent environmental compatibility.

The object was achieved by a liquid cleaning agent which largely contains only alkyl polyglycoside as the surfactant.

The invention therefore relates to a liquid, foaming cleaning agent with increased viscosity consisting of 5 to 40 % By weight alkyl polyglycoside, 0.1 to 2.9 % By weight of anionic surfactant ,, 0 to 3 % By weight of other surfactants, and conventional non-surfactant additives and water ad 100 wt .-%.

The use of alkyl polyglycosides in detergents and cleaning agents is known in combination with other surfactants. AT-PS 135 333 already describes the effect of lauryl glycoside combined with the sodium salt of ricinol sulfuric acid ester as a wool detergent. In US Pat. No. 3,721,633, alkyl polyglycosides in combination with builder substances, such as nitrilotriacetic acid or sodium tripolyphosphate, are described as detergents. The combination of alkyl polyglycosides EP-A-0 105 556 claims fatty alcohol oxyethylates as the liquid detergent. Manual detergents using alkyl polyglycosides are described in EP-A-0 070 074, EP-A-0 070 075 and EP-A-0 070 076, Anionic surfactants are used as cosurfactants. DE-OS 35 34 082 also has analogous content, fatty alkyl glycosides having 1 to 1.4 glycoside units per fatty alkyl radical being mentioned. Alkyl sulfate or alkyl ether sulfates in each case in combination with fatty acid alkanolamides serve as cosurfactants. Finally, EP-AO 199 765 describes a liquid detergent or dishwashing detergent with a similar claim.

All of these combinations imply the disadvantage of a relatively high content of non-purely native or petrochemical-based cosurfactants, and therefore usually also of limited environmental compatibility and skin friendliness, with a comparatively more or less good cleaning effect.
So calls for. B. EP-AO 070 074 a minimum cosurfactant content of alkylbenzenesulfonate of 50% or for sulfates of 60% based on total surfactant.

And EP-O 199 765 describes cleaning liquids with a minimum anionic cosurfactant content of 3%.

An ideal solution to the problem would be to use alkyl polyglycoside as the only surfactant component in the cleaning liquid. Defacto pure alkyl polyglycoside solutions also have excellent cleaning effects, provided they are sufficiently hydrophobic. The latter is achieved through a longer-chain hydrophobic alkyl radical or through a less pronounced hydrophilic part of the molecule.

It has now surprisingly been found that, when extremely small amounts of anionic surfactant are added to alkyl polyglycosides, good foaming power and high rinsing action with good skin tolerance can be observed in the liquid cleaning agents according to the invention, with a viscosity increase by a factor of 15 to 20 compared to the pure alkyl polyglycoside concentrate watch is.

Alkyl polyglycosides

Alkyl polyglycosides used according to the invention satisfy formula I.



RON _n I,



in which R represents a linear or branched, saturated or unsaturated aliphatic alkyl radical having 10 to 18 carbon atoms or mixtures thereof and Z _{n represents} a polyglycosyl radical with n = 1.0 to 3 hexose or pentose units or mixtures thereof.

Alkyl polygylcosides with fatty alkyl radicals with 12 to 16 carbon atoms and a polyglycosyl radical with n = 1.1 to 2 are preferred. Alkyl polyglycosides with n = 1.1 to 1.5 are particularly preferred.

The alkyl polyglycosides used according to the invention can be produced by known processes based on renewable raw materials. For example, dextrose is reacted with n-butanol to give butylpolyglycoside mixtures in the presence of an acidic catalyst, which are transglycosidated with long-chain alcohols in the presence of an acidic catalyst to give the desired alkylpolyglycoside mixtures.

The structure of the products can be varied within certain limits. The alkyl radical R is determined by the choice of the long-chain alcohol. Favorable for economic reasons are the industrially accessible surfactant alcohols with 10 to 18 carbon atoms, in particular native fatty alcohols from the hydrogenation of fatty acids or fatty acid derivatives. Ziegler alcohols or oxo alcohols can also be used.

The polyglycosyl radical Z _n is determined, on the one hand, by the selection of the carbohydrate and, on the other hand, by setting the average degree of polymerization n. B. according to DE-OS 19 43 689. In principle, it is known that polysaccharides, e.g. B. starch, maltodextrins, dextrose, galactose, mannose, xylose etc. can be used. The industrially available carbohydrates starch, maltodextrins and especially dextrose are preferred. Because the economically interesting alkyl polygylcoside syntheses not being regio- and stereoselective, the alkyl polygylcosides are always mixtures of oligomers, which in turn represent mixtures of different isomeric forms. They exist side by side with α- and β-glycosidic bonds in pyranose and furanose form. The links between two saccharide residues are also different.

Alkyl polyglycosides used according to the invention can also be prepared by mixing alkyl polyglycosides with alkyl monoglycosides. The latter can e.g. B. according to EP-A-0 092 355 using polar solvents such as acetone, from alkyl polyglycosides.

The degree of glycosidation is advantageously determined by means of 1 H-NMR.

The cleaning agents according to the invention contain 5 to 40%, preferably 10 to 30%, of alkyl polyglycoside in aqueous solution.

Compared to all other surfactants used in cleaning agents, the alkyl polyglycosides are considered to be extremely environmentally compatible. The degree of biodegradation for the alkyl polygylcosides according to the invention, determined by means of a sewage plant simulation model / DOC analysis, is 96 ± 3%. This number can be seen against the background that with this test method (total degradation) a degree of degradation> 70% already indicates that the substance is readily degradable.

The acute oral toxicity LD 50 (rat) as well as the aquatic toxicity LC 50 (gold orfe) and EC 50 (daphnia) and values of> 10,000 mg / kg, 12 or 30 mg / l are three to five times cheaper than the corresponding values of today's most important surfactants. The same applies to the skin and mucous membrane compatibility, which is particularly important for detergents.

The alkyl polyglycosides according to the invention are obtained as an approximately 50% aqueous solution due to the synthesis. The solubility in water is not too high due to the hydrophobic structure.

Anionic surfactant

Suitable anionic surfactants are fatty alcohol ether sulfates, fatty alcohol sulfates, fatty alcohol ether phosphates, carboxymethylated fatty alcohol oxethylates, paraffin sulfonates, olefin sulfonates, alkylbenzenesulfonates and mixtures thereof. Anionic surfactants with alkyl or alkylene radicals of 10 to 20 carbon atoms in the hydrophobic part of the molecule are particularly suitable. Fatty alcohol ether sulfates with 1 to 4 mol ethylene oxide / mol, carboxymethylated fatty alcohol oxethylates with 2 to 10 mol ethylene oxide / mol and fatty alcohol sulfates are preferred. Preferred cations are Na, K, NH₄ and Mg or mixtures thereof.

The cleaning concentrates according to the invention contain 0.1 to 2.9% anionic surfactant in aqueous solution. 0.15 to 2.5% are preferred.

Other components

By adding solvents such as low-molecular, mono- and polyhydric alcohols and glycol ethers, the solubility can be increased significantly, especially at low temperatures. Particularly suitable solvents are ethanol, isopropanol, 1,2-propylene glycol, etc. Typical concentrations in the cleaning agent and 3 to 12% in the aqueous solution.

In combination of the solvent with electrolytes, the solubility can be achieved especially at low temperatures, e.g. T. increase significantly. Alkali and alkaline earth metal halides have proven to be suitable electrolytes. The ratio of solvent / electrolyte can be 1: 1 to 8: 1.

Other additives are nonionic, ampholytic and / or zwitterionic surfactants with total concentrations between 0 and 3% in the aqueous solution.

Finally, the cleaning liquid according to the invention can contain small amounts (0.1 to 3 percent by weight) of customary dyes and perfume oils, and also alkanolamines or hydrotropes, such as non-surfactant alkylbenzenesulfoants having 1 to 3 carbon atoms in the alkyl radical - usually as sodium salts - and urea.

To set a suitable viscosity, water-soluble polymers such as carboxmethyl cellulose, hydroxyethyl cellulose, xanthans, polyethylene oxide, polyacrylate, etc. can optionally be added.

Citric acid, EDTA, NTA and other complexing agents have proven to be further suitable additives.

Examples

The following examples are intended to illustrate the invention.

The mini dish test (cf. RM Anstett and EJ Schuck JAOCS 43, 576 (1966) was carried out to test the detergent action.
Watch glasses loaded with grease are manually cleaned at elevated temperature with a brush in the surfactant solution. The test conditions (preparations, geometries, amounts and concentrations of substances, temperatures, temperature gradients, times) are precisely defined. The test is carried out by several people and provides reproducible results. Disappearing foam shows the number of cleaned plates (watch glasses). Pork lard served as soiling, which was applied to the glasses at 50.0 ° C, which are then subjected to a defined cooling process to 23 ° C (room temperature). The initial rinse temperature is also 50 ° C.

The foaming power of the cleaning agent was determined in accordance with DIN 53 902, Part 1. The concentration of detergent substance was 1 g / l in each case. The foam volume was registered after 5 minutes.

The viscosity of the cleaning liquid was measured in a rotary viscometer (Haake RV 20) under defined shear rates (D approx. 10 sec⁻¹).

To determine the clear point, 10 g of cleaning agent were cooled to -20 ° C. in a Shukoff flask and then heated. The temperature of the product is measured with complete clarification.

Tables 1 a and 1 b show the properties of the preparations according to the invention. The addition of small amounts of anionic surfactant to solutions of hydrophobically adjusted alkyl polyglycoside (cf. Example 1 (V) brings about a clarification of the liquid. At the same time, foaming power and viscosity increase sharply and very soon reach the level of commercially available cleaning agents (Example 7 (V). The cleaning effect is not affected by the addition of anionic surfactants as part of the measurement error and corresponds completely to the standard on the market.

The following abbreviations were used in the tables:

The diagram (Fig. I) shows the properties of the preparations according to the invention of APG 1 / alkyl ether sulfate as a function of the ether sulfate additive in detail, the APG 1 content = 15% by weight. While the foaming power increases very strongly with the addition of ether sulfate, the clear point changes only relatively little. The pronounced viscosity maximum in the range of low anionic surfactant concentrations is completely unexpected. This property, which is the basis of the present invention, was also observed when other anionic surfactants were added. With the help of such a diagram, cleaning agents can also be tailored with regard to optimal environmental compatibility.

S =

Schaum [ml] bei 25 °C nach 300 sec.

=

Viskosität [mPa·s] bei 25 °C

T =

Reinigungswirkung [Teller]

K =

Klarpunkt [°C]

The following abbreviations / measures were used in Figure I:

S =

Foam [ml] at 25 ° C after 300 sec.

=

Viscosity [mPa · s] at 25 ° C

T =

Cleaning effect [plate]

K =

Clear point [° C]

Claims (10)

Liquid, foaming cleaning agent with increased viscosity consisting of 5 to 40 % By weight alkyl polygylcoside, 0.1 to 2.9 % By weight of anionic surfactant, 0 to 3 % By weight of other surfactants, and conventional non-surfactant additives and water ad 100 wt .-%. Liquid, foaming cleaning agent according to claim 1,
characterized,
that the alkyl polygylcoside of formula I



RON _n I



corresponds, where R is a saturated or unsaturated, branched or unbranched alkyl radical having 10 to 18 carbon atoms, Z _{n is} a polyglycosyl radical with n = 1 to 3 hexose or pentose units or mixtures thereof. Liquid, foaming cleaning agent according to claim 1,
characterized,
that the alkyl polyglycoside of formula I



RON _n I



corresponds, where R is a saturated or unsaturated, fatty alcohol having 10 to 18 carbon atoms and Z _{n is} a polyglycosyl radical with n = 1.1 to 2 glycoside units. Liquid, foaming cleaning agent according to claims 1 to 3,
characterized,
that the anionic surfactant consists of fatty alcohol ether sulfate, fatty alcohol sulfate, carboxymethylated fatty alcohol oxyethylate, olefin sulfonate, Alkanesulfonate, alkylbenzenesulfonate or mixtures thereof. Liquid, foaming cleaning agent according to claims 1 to 4,
characterized,
that the anionic surfactant is fatty alcohol ether sulfate. Liquid, foaming cleaning agent according to claims 1 to 4,
characterized,
that the anionic surfactant is fatty alcohol sulfate. Liquid, foaming cleaning agent according to claims 1 to 4,
characterized,
that the anionic surfactant is carboxymethylated fatty alcohol oxyethylate. Liquid, foaming cleaning agent according to claims 1 to 4,
characterized,
that the anionic surfactant is alkanesulfonate. Liquid, foaming cleaning agent according to claims 1 to 8,
characterized,
that solvents such as mono- and polyhydric alcohols, electrolytes, complexing agents, hydrotropics, polymers, dyes, fragrances etc. are used as further additives. Use of the liquid, foaming cleaning agent with increased viscosity according to claims 1 to 9 as a manual detergent.

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