EP0084154A1 - Use of viscosity regulators in surface-active concentrates - Google Patents

Abstract

Process for reducing the viscosity of aqueous concentrates of anionic surfactants by adding thereto a small quantity of a compound containing polyglycol ether groups; and the aqueous concentrates prepared thereby.

Description

In the production of powdery or granular detergents and cleaning agents by the hot spray process customary on an industrial scale, aqueous slurries (called "slurry") are used which contain a large part or all of the detergent constituents. From an economic point of view, it is important that the slurry be as rich in detergent components as possible. H. is as low in liquid fiber as possible. The lowest possible amount of water is therefore used to prepare the slurries. Concentration is limited by the highest possible viscosity at which the slurry is just processing, i.e. especially can be pumped and sprayed.

An essential component of detergents and cleaning agents are surfactants. Anionic surfactants are mostly used in the production of detergent slurries as paste-like concentrates with a surfactant content of approx. 30 to approx. 60% by weight; a higher surfactant content would be desirable, but is problematic because the processability of the surfactant concentrates is then no longer guaranteed due to the excess viscosity. A peculiarity in the rheological behavior of surfactant concentrates is that they act on the addition of water not with a reduction in viscosity but first with a thickening to a gel-like state, which causes further problems for the processor to grow. For example, it is often not easy to get gel clumps back into solution, or valves on pumps and containers become blocked.

Various proposals have been made to solve these problems. DE-OS 22 51 405, for example, describes the salts of certain carboxylic acids, in particular hydroxycarboxylic acids, as viscosity regulators. According to the teaching of DE-OS 23 05 554, sulfonated aromatic compounds are suitable for this purpose. DE-OS 23 26 006 mentions sulfates or sulfonates of aliphatic, optionally substituted hydrocarbons as viscosity reducers. The addition of lower alkanols is also listed as a possibility for reducing the viscosity in the publications mentioned. Furthermore, the addition of the well-known hydrotropes such. B. cumene sulfonate, or of acidic phosphoric acid esters (DE-AS 16 17 160) or of polyhydric alcohols, certain carboxylic acids and / or esters of these compounds (EP-OS 8060). From European patent application 24 711 it is known to add sulfates of certain polyalkylene ether glycols to improve the flow behavior of anionic surfactant concentrates.

Some of the additives mentioned in the literature only work with certain surfactants, others dilute the concentrates too much with additives that are not effective in washing, since they are only effective in larger amounts, while others, such as lower alkanols, lower the flash point.

It is therefore an object of the present invention to use viscosity ^reducers for aqueous concentrates of anionic surfactants, so that they can be processed in higher concentrations than hitherto or have no increase in viscosity when diluted with water. In particular, wants the invention lower the viscosity of concentrates of alkyl sulfates, alkylarylsulfonates and α-sulfofatty acid esters.

It has now been found that by using polyglycol ether-containing compounds from the group of polyethylene glycols with a molecular weight of 600 to 6000, polypropylene glycols with a molecular weight of 250 to 4000, the adducts of 20 to 80 mol ethylene oxide with aliphatic alcohols with 10 up to 20 carbon atoms or from 20 to 60 mol ethylene oxide of alkylphenols having 6 to 12 carbon atoms in the alkyl group, which are present in amounts of at most 10% by weight, based on the surfactant concentrates, of aqueous concentrates of the water-soluble salts of the anionic surfactants α-sulfofatty acid esters , Alkylarylsulfonates, alkyl sulfates as viscosity regulators, the viscosity of these concentrates at the usual processing temperature of the concentrates can reduce a viscosity reduction to a value of at most 10,000 mPas.

The addition of certain inorganic salts, e.g. B. trisodium phosphate (Na PO ₄ ) or sodium sulfate (Na SO) or alkali hydroxide as a viscosity regulator has a viscosity-reducing effect, in particular in the case of alkyl sulfate concentrates.

Depending on the type of surfactant, the surfactants are present in the concentrates in amounts of approximately 30% by weight of α-sulfofatty acid esters, alkyl sulfates) or, as in the case of alkylarylsulfonates, in amounts of approximately 50 to 60 percent by weight. By inventing According to the use of the viscosity reducer, the viscosity of the concentrates at the respective processing temperature, ie at the temperature at which the surfactant concentrates are produced, pumped, mixed with other detergent constituents or sprayed, which is done between about 50 and 90 ° C, on a Reduce the processable viscosity by at most 10000 mPas. Another very important advantage of the use according to the invention is that the surfactant content of the concentrates can be increased by 3 to 15% by weight without the viscosity exceeding the upper limit of about 10,000 mPas permissible for processability, which means that the surfactant concentrates accordingly contain less water, which is very important for the economy of production and the quality of the detergents.

The viscosity regulators are added to the aqueous surfactant concentrates in amounts of preferably 0.1 to 5% by weight. Amounts of 0.5 to 3% by weight are particularly preferred. This information relates to the aqueous surfactant concentrate. In particular, the amount of the viscosity regulator is determined by the desired lowering of the viscosity of the respective concentrate. In some cases, the maximum achievable viscosity reduction is achieved with an addition of 3% by weight.

The polyalkylene glycols suitable as viscosity regulators are derived from straight-chain or branched glycols having 2 or 3 carbon atoms. Particularly suitable polyethylene glycols have a molecular weight of 1000 to 4000, in particular 1500 to 2500. Such products are commercially available, for example, under the name "Polywachs" (Chemische Werke Hüls, Marl, Federal Republic of Germany).

Particularly suitable polypropylene glycols have a molecular weight of 400 to 2000, in particular 400 to 800.

The addition products of ethylene oxide with aliphatic alcohols suitable as viscosity regulators are derived in particular from fatty acids of natural fats, for example from coconut oil or tallow fat. However, corresponding Ziegler or oxo alcohol ethoxylates can also be used, a degree of ethoxylation of 30 to 80 moles of ethylene oxide per mole of alcohol, in particular 40 to 60 moles of ethylene oxide per mole of alcohol, giving particularly good results. A particularly effective viscosity regulator for α-sulfofatty acid esters and alkylarylsulfonate concentrates is, for example, the adduct of 50 moles of ethylene oxide with 1 mole of tallow alcohol.

Suitable alkylphenol ethoxylates have in particular 8 to 12, for example predominantly 9 carbon atoms in the alkyl group and preferably 30 to 50 moles of ethylene oxide per mole of alkylphenol in the molecule. The adduct of 40 moles of ethylene oxide with 1 mole of nonylphenol is an example of a viscosity regulator which is particularly effective with concentrates of α-sulfofatty acid esters and alkylarylsulfonates.

The surfactant concentrates, whose viscosity is determined by the _; viscosity regulators can be influenced, contain in particular the following surfactants:

I. α-sulfofatty acid ester (SFE) ^-

These surfactants are derived from fatty acids with 10 to 20, preferably 12 to 18 carbon atoms and from aliphatic alcohols with 1 to 10, preferably 1 to 2 carbon atoms in the molecule. The The sulfo group is introduced either by sulfonation of the fatty acid and subsequent esterification of the carboxyl group with the alcohol or by sulfonation of a corresponding fatty acid ester. According to both methods, esters of sulfo fatty acids are obtained which contain the sulfo acid group in the α-position. Α-Sulfofatty acid esters which are particularly suitable as surfactants are the alkali metal or ammonium salts of the methyl and ethyl esters of tallow fatty acid with a sulfo group in the α-position, the acid component of which essentially consists of saturated and unsaturated C ₁₆ and C ₁₈ fatty acids.

Alkyl sulfates (FAS)

Surfactants of this class are the sulfuric acid esters of fatty alcohols. The alcohol component can be saturated or unsaturated and generally has 8 to 24 carbon atoms, preferably 10 to 18 carbon atoms. The alcohol is derived, for example, from coconut oil or in particular from tallow fat. FAS are usually in the form of their alkali or ammonium salts.

Alkylarylsulfonates (ABS)

ABS are the sulfonation products of alkylbenzene in particular. The alkyl group can be straight-chain or branched, saturated or unsaturated. The alkyl radical preferably has 4 to 16, in particular 6 to 14, carbons. ABS, whose alkyl radicals have 8 to 12 carbon atoms and are present as alkali or ammonium salts, are of particular importance.

In addition to these anionic surfactants, the aqueous surfactant concentrates according to the invention can also contain other surface-active agents and inorganic salts such as sodium chloride and / or sodium sulfate, which in turn can also have an influence on the viscosity of the concentrates.

Example: 1 e I. α-sulfofatty acid esters example 1

An aqueous concentrate of methyl α-sulfot tallow fatty acid with approx. 29% by weight of active substance had a viscosity in the temperature range from 40 to 65 ° C without the addition of a viscosity reducer between approx. 31,000 mPas (40 ° C) and approx. 25,000 mPas (65 ° C). After addition of 1.5% by weight, based on the concentrate, of nonylphenol + 20 moles of ethylene oxide, the concentrate had a viscosity between approximately 1,500 mPas (65 ° C.) and approximately 14,000 (40 ° C.). Similar or better results were obtained if the same amount of nonylphenol with 40 or 60 moles of ethylene oxide was used as the viscosity regulator. On the other hand, a significantly lower effect was obtained with nonylphenol + 10 and nonylphenol + 6.5 mol ethylene oxide, i.e. typical detergent surfactants.

Example 2

The α-sulfotalg fatty acid methyl ester concentrate from Example 1 was mixed with 1.5% by weight of tallow alcohol + 25 moles of ethylene oxide. The viscosity was then between approximately 1,500 mPas (65 ° C) and approximately 22,000 mPas (40 ° C). Equal amounts of tallow alcohol + 50 moles of ethylene oxide or tallow alcohol + 80 moles of ethylene oxide gave comparable or better results, while typical detergent surfactants such as tallow alcohol + 14 moles of ethylene oxide and tallow alcohol + 5 moles of ethylene oxide gave poorer results.

Example 3

The same concentrate as in the previous examples was mixed with 1.5% by weight polypropylene glycol, molecular weight 2000. The viscosity decreased in the range from 40 to 65 ° C to 3000 mPas (65 ° C) to 10,000 mPas (40 ° C). When using the same amount of polypropylene glycol, molecular weight 400 and 600, the viscosity at 40 ° C was below 6000 mPas.

Example 4

The same surfactant concentrate as in the previous examples was mixed with 1.5% by weight of polyethylene glycol, molecular weight 2000. The viscosity dropped to approx. 9000 mPas (40 ° C) or approx. 1000 mPas (65 ° C). Similar results were obtained with other polyethylene glycols with molecular weights between approximately 1000 and approximately 4000, while the viscosity-reducing effect of polyethylene glycols with molecular weights below 1000 was significantly lower.

II. Alkylarylsulfonates Example 5

An alkylbenzenesulfonate paste with 59% by weight of active substance had, without the addition of a viscosity reducer, a viscosity of approximately 17,000 mPas (40 ° C.) or approximately 13,000 mPas (55 ° C.). After adding 1.5% by weight of polyethylene glycol, molecular weight 2000, the viscosity was only approx. 2800 mPas; (40-55 C). Comparable results were obtained if the ABS paste was given the same amount of sebum. Amount of tallow alcohol + 50 moles of ethylene oxide or nonylphenol + 40 moles of ethylene oxide was added, while tallow alcohol + 14 moles of ethylene oxide caused a significantly lower viscosity reduction.

III. Alkyl sulfates Example 6

A tallow alcohol sulfate paste with 31.2% by weight of active substance had a viscosity between about 35,000 mPas (55 ° C) and about 13,000 mPas (80 ° C) without addition. After the addition of 1.5% by weight of polyethylene glycol molecular weight 2000, the viscosity dropped to approximately 10,000 mPas (55 ° C) or approximately 8000 (80 ° C).

Example 7

A tallow alcohol sulfate paste with 30.1% by weight of active substance had a viscosity between approx. Without the addition of a viscosity reducer; 35,000 mPas (55 ° C) and approx. 10,000 mPas (80 ° C). The addition of 2.0% by weight of polyethylene glycol, molecular weight 2000, brought about a reduction in the viscosity to values between approximately 22,000 mPas (55 ° C) and approximately 6000 (80 ° C). The addition of 3% by weight of nonylphenol + 20 moles of ethylene oxide resulted in a viscosity of 9500 mPas (55 ° C) or 3100 mPas (80 ° C). The addition of 3% by weight of tallow alcohol + 25 moles of ethylene oxide caused the viscosity to drop to 21,000 mPas (55 ° C) or 2100 mPas (80 ° C).

By using the viscosity-reducing additives according to the invention, the active substance of the surfactant concentrates can be increased by about 3 to 5 percent by weight, depending on the type of surfactant, without the viscosity increasing to a value of about 10,000 mPas; this viscosity represents approximately the upper limit for the pumpability and processability of surfactant concentrates in the detergent slurry. According to the higher active substance concentration, the water content of the surfactant concentrates can be reduced by the same amount; this means considerable progress in the industrial production of detergents.

Claims (6)

1. Use of higher molecular weight compounds containing polyglycol ether as a viscosity reducer for aqueous concentrates of anionic surfactants, characterized in that compounds of the polyethylene glycols with a molecular weight of 600 to 6000, the polypropylene glycols with a molecular weight of 250 to 4000, the adducts of 20 to 80 mol Ethylene oxide with aliphatic alcohols with 10 to 20 carbon atoms, the adducts of 20 to 60 moles of ethylene oxide with alkylphenols with 6 to 12 carbon atoms in the group comprising alkyl groups in amounts of at most .10% by weight, based on the surfactant concentrates, aqueous concentrates of the water-soluble Salts of the anionic surfactants α-sulfofatty acid esters, alkylarylsulfonates, alkyl sulfates are added, so that at the usual processing temperature of these concentrates the viscosity decreases to a value of at most 10,000 mPas. 2. Use according to claim 1, characterized in that the viscosity regulator in amounts of 0.1 to 5 wt .-% and in particular in amounts of 0.5 to 3 wt .-%, each based on the surfactant concentrate. 3. Use according to claims 1 and '2, characterized in that polyethylene glycol having a molecular weight of 1000 to 4000, preferably from 1500 to 2500, is added as the viscosity regulator. 4. Use according to claims 1 and 2, characterized in that polypropylene glycol having a molecular weight of 400 to 2000, preferably 400 to 800, is added as the viscosity regulator. 5. Use according to claims 1 and 2, characterized in that addition products of 30 to 80 moles of ethylene oxide, preferably 40 to 60 moles of ethylene oxide with fatty alcohols, preferably tallow fatty alcohol, are added as viscosity regulators. 6. Use according to claims 1 and 2, characterized in that addition products of 30 to 50 moles of ethylene oxide, preferably 40 moles of ethylene oxide and alkylphenol with 8 to 12, preferably predominantly 9 carbon, as viscosity regulators; atoms in the alkyl group, especially nonylphenol.