EA044448B1 - LIQUID WASHING CONCENTRATE - Google Patents

Description

Description of the invention

The invention relates to a liquid detergent concentrate containing at least one alkali metal hydroxide. In addition, the invention relates to a method for producing a liquid detergent concentrate containing an alkali metal hydroxide.

State of the art

To clean dishes, in particular to remove dirt stuck to dishes, alkaline detergents are preferably used.

Liquid detergents based on hydroxides and complexing agents are known in the art and have advantages over powder compositions. On the one hand, this does not generate dust and, on the other hand, it simplifies handling when dosing with pumps.

Liquid detergent concentrates containing alkali metal hydroxide are described, for example, in patent document DE 199 06 660 A1, where a water content of 53-80% by weight is specified. However, such a high water content in liquid detergent concentrates is detrimental to the stability of the concentrate and significantly increases the required volume of detergent concentrate, which necessitates the need for additional containers. It is in the industrial field that highly concentrated cleaning concentrates with small volumes for storage and transport are preferred, as well as for environmental reasons.

To counteract high water content, various basic approaches can be traced in the prior art. One strategy is non-aqueous liquid detergent concentrates, as described in patent document EP 1 181 346; but such compositions are associated with reduced cleaning power or the need to handle unhealthy or environmentally hazardous chemicals.

Another approach is to reduce the water content of aqueous detergent concentrates, which, however, results in an increase in viscosity. For example, patent document DE 100 02 710 A1 describes a creamy detergent concentrate with a water content of 32.5%.

Detergent concentrates on an industrial scale are dosed by automatic dispensers and automatically diluted with water to the desired final concentration to form a ready-to-use detergent. These automatic dispensers mainly use peristaltic hose pumps with pinch rollers to dose detergent concentrate, and these peristaltic hose pumps can only dispense liquid detergent concentrates. Due to their high viscosity, creamy or paste-like detergent concentrates are not suitable for use in automatic dispensers - in the worst case, this leads to clogging and destruction of the peristaltic hose pump or automatic dispenser.

It is therefore an object of the present invention to provide a highly concentrated but still liquid alkali metal hydroxide based cleaning concentrate which can be dispensed and diluted by an automatic dispenser.

The essence of the invention

This object is achieved by means of a liquid detergent concentrate comprising (i) from 22 to 46 wt.% alkali metal hydroxide, (ii) from 5 to 50 wt.% dispersant, complexing agent or combination thereof, (iii) from 0 to 5 wt.% surfactant, (iv) from 0 to 5 wt.% auxiliary additive, and (v) from 28 to 39 wt.% water, and the detergent concentrate is a suspension.

It is preferably provided that this suspension has a viscosity of maximum 6500 mPa-s, measured according to ISO 2555:1989 at a temperature of 20°C with a rotation speed of 5 rpm.

For example, the measurement can be carried out using a Brookfield viscometer.

The suspensions described herein are stable suspensions.

It has been discovered within the scope of the invention that by reducing the water content, the normally associated increase in viscosity can be avoided when the detergent concentrate is obtained in the form of a suspension.

It is preferably provided that the cleaning concentrate does not have additional components.

However, obtaining a stable suspension that has a high concentration of alkali metal hydroxide in a small amount of water is not possible using traditional methods for preparing suspensions. Stable suspensions of alkali metal hydroxide cannot be prepared by known methods for preparing suspensions according to the prior art, and, insofar as (unstable) suspensions can be obtained, they have such a high viscosity that dosing is impossible.

Therefore, the present invention also aims to provide a method for producing a stable suspension.

The problem is solved by means of a method for producing a suspension comprising (i) from 22 to 46 wt.% alkali metal hydroxide, (ii) from 5 to 50 wt.% dispersant, complex

- 1 044448 excipient or combination thereof, (iii) from 0 to 5 wt.% surfactant, (iv) from 0 to 5 wt.% auxiliary additive, and (v) from 28 to 39 wt.% water, wherein the method includes the stages:

a) preparing a batch of dispersant, complexing agent or combination thereof in the aqueous phase,

b) if necessary, add auxiliary additives,

c) in case of adding auxiliary additives, then adding an additional portion of dispersant,

d) adding a portion of alkali metal hydroxide in the form of an aqueous solution,

e) if necessary, add a surfactant,

f) adding an additional portion of alkali metal hydroxide,

g) adding a dispersant,

h) adding an additional portion of alkali metal hydroxide, wherein the addition steps are carried out with stirring, and at least the addition steps d) to h) are carried out in such a way that the temperature of the aqueous phase is maintained at a maximum of 40°C, preferably at a maximum of 35°C.

In this case, adding a portion implies that at this stage only a part, and not the entire amount of a given component, is introduced.

Using this method, it is possible to obtain a stable suspension - that is, a suspension that does not separate during storage and therefore during use, and in which this does not lead to the formation of sediment and, accordingly, in which no solid substance is deposited. Thus, for the first time, it is possible to obtain a stable suspension containing large quantities of alkali metal hydroxide, and - in contrast to the creamy composition according to patent document DE 100 02 710 A1 - a liquid, that is, pumpable and dosable, detergent concentrate can be obtained.

Terms.

Within the framework of the present invention, the terms specified in the invention are understood as follows.

The detergent is a ready-to-use cleaning composition, and is a mixture of detergent concentrate with water. The detergent is preferably a ready-to-use composition for cleaning dishes.

A detergent concentrate is a composition in which the components - with the exception of water as a diluent - are present in a more concentrated form than in a ready-to-use detergent.

By stable suspension is meant a suspension that does not separate during storage and use, and in which this does not lead to the formation of sediment. Stability can be assessed, for example, by measuring viscosity and density, which may change only slightly over time. Stability can also be determined by testing under varying climatic conditions and, accordingly, by storage for a certain period of time and subsequent optical inspection (separation into two or more phases). The measurement possibility here is to check whether the viscosity and density change after 30 days of storage, that is, without stirring or stirring the suspension, at a temperature of 20°C, by less than 5% as a result of sedimentation.

By alkali metal hydroxide is meant hydroxides of at least one alkali metal. Therefore, we can also talk about a mixture of many alkali metal hydroxides. Preferably, sodium hydroxide (NaOH) and potassium hydroxide (KOH) are used.

A dispersant is an additive that improves the optimal mixing of at least two essentially immiscible substances. In this case, the purpose of the dispersant is also to improve the cleaning ability of the detergent. By dispersant can also be meant a mixture of two or more dispersants. At the same time, the dispersant in the detergent also helps to destroy old deposits.

A complexing agent, or chelating agent, is an additive that forms chelate complexes with metal ions. This masks the undesirable properties of certain metal ions. Divalent metal ions, especially alkaline earth metal ions such as Ca ²⁺ and Mg ²⁺ , are particularly undesirable in the purification process. Therefore, the complexing agent is preferably one that forms complexes with alkaline earth metal ions.

However, some complexing agents in detergents also act as dispersants, and vice versa.

Surfactants are substances that reduce the surface tension of a liquid or the surface tension at the interface between two phases, and thereby promote the formation of dispersions. They can also act as solvents. Maybe

- 2 044448 A mixture of two or more surfactants is also available.

In detergents, their purpose is to assist in the transfer of grease and dirt particles adhering to dishes into the aqueous phase. They can be selected, for example, from the group of alkylbenzenesulfonates, alkylpolyglycosides, esterquats, aliphatic alcohol ethoxylates, aliphatic alcohol sulphates and aliphatic alcohol ether sulfates, or mixtures thereof, with aliphatic alcohol ethoxylates exhibiting particularly good purification efficiency.

Auxiliary additives include compounds which, in a finished detergent composition, facilitate its use or may enhance its cleaning effect. But auxiliary additives may also include compounds that promote the formation of suspension. Typical auxiliary additives are, for example, defoamers, that is, substances that reduce the formation of unwanted foam when stirring the detergent, thickeners, which increase the viscosity of the detergent, cleaning enhancers, which enhance the cleaning effect of alkali metal hydroxides, threshold agents, suspending agents or, also fragrances, to name just a few examples.

Defoamers can be selected, for example, from the group of paraffinic oils, silicone oils or mixtures thereof. One example of a possible paraffin oil is petroleum jelly, technical grade (Bussetti); An example of silicone oil is Silikonol 100 (Bussetti). The defoamer content may be, for example, from 0 to 5% by weight.

Thickeners can be selected, for example, from the group of 1,2,3-propanetriol, 2-propanol, xanthan gum (eg Keltrol types, from CP Kelco). The content of thickeners can be, for example, from 0 to 5% by weight.

Cleaning enhancers can be substances that have a primary effect, that is, they act by increasing the pH value, and they can be monoethanolamine or triethanolamine. Other cleaning enhancers include polymers or alkaline compounds, such as Mirapol SURF S (a mixture based on Na ₂ CO ₃ from Rhodia), Polyquart Ampho 149 (from BASF). The content of cleaning enhancers can be, for example, from 0 to 5% by weight.

Suspending agents can be selected, for example, from the group of polyvinyl alcohol or polyvinylpyrrolidone.

The content of suspending agents can be, for example, from 0 to 2% by weight. Preferably, no suspending agent is provided since it has been shown that increasing the amount of suspending agent leads to separation and sedimentation.

Threshold substances are compounds that, at very low (below stoichiometric) concentrations, hinder or at least greatly slow down the formation of precipitation. In a supersaturated solution, the formation of an insoluble precipitate is hampered by the fact that substances exhibiting a threshold effect block the surface of the initially formed single crystals by adsorption, so that no large crystals can form as a result of layering. For example, compounds from the group of low molecular weight phosphonates and high molecular weight complexing agents (for example, polycarboxylates) are known as threshold substances in the detergent industry.

A particularly suitable threshold substance was Hydrodis WP 40 with the main component being an oligomeric phosphonic acid. Although it is common knowledge that many substances with threshold activity have a solubility problem in aqueous solutions with high calcium concentrations (referred to as calcium susceptibility), upon the addition of oligomeric phosphonic acid in the form of Hydrodis WP 40, the absence of a Ca-sensitive zone was observed. The addition of Hydrodis WP 40 ensures that the detergent concentrate remains stable and has a very good calcium binding capacity as well as good cleaning action. The content of the threshold substance is preferably from 2 to 5 wt.%.

Detailed Description of the Invention

Further advantages and details of the invention are explained below. The embodiments relate equally to a liquid detergent concentrate and a method for producing a suspension. True, for reasons of better understanding, the method of obtaining is first described more fully.

Stage a). Preparation of a portion of a dispersant, complexing agent, or combination thereof in an aqueous solution.

First, a solution of a dispersant, complexing agent, or a combination of both in water is prepared.

Preferably, a mixture of the first and second complexing agents is prepared.

The first complexing agent may be selected, for example, from the group of aminocarboxylic acids, and the second complexing agent from the group of aminophosphonic acids.

In one embodiment, in step a) a mixture of an aqueous solution of a first complexing agent (for example, such as an aminocarboxylic acid, more preferably methyl glycine diacetic acid or a salt thereof) and an aqueous solution of a second complexing agent (for example, such as an aminophosphonic acid, more preferably diethylenetriaminepentamethylenephosphonic acid) can be prepared or its salt).

- 3 044448

Stage b). If necessary, add auxiliary additives.

In step b) auxiliary additives may be mixed.

Stage c). Adding an additional portion of dispersant.

When adding auxiliary additives, it is preferable to introduce an additional portion of the dispersant in the next stage. The introduction of auxiliary additives and the subsequent addition of a dispersant lead to a stable suspension.

Stage d). Adding a portion of alkali metal hydroxide in the form of an aqueous solution.

In step d) the first addition of alkali metal hydroxide is carried out with stirring, namely in the form of an aqueous solution. With regard to the total amount of alkali metal hydroxide in this step, it is preferable to add less than half, especially preferably less than a third of the final amount of alkali metal hydroxide.

As aqueous solutions, NaOH or KOH solutions are preferably considered, it makes no difference whether a NaOH solution or a KOH solution is used, or whether a NaOH solution and a KOH solution are used separately from each other, or whether a NaOH/KOH mixture is added. All combinations of them are also possible.

Step e).Addition of surfactant.

In step e) the surfactant is added with stirring.

Stage f). Adding an additional portion of alkali metal hydroxide.

In step f) an additional portion of alkali metal hydroxide is added in the form of a solid. The addition is preferably accomplished by stirring the NaOH and/or KOH granules.

Stage g). Adding an additional portion of dispersant.

In stage g) an additional portion of the dispersant is added, which is added while mixing.

Stage h). Adding an additional portion of alkali metal hydroxide.

In step h) the remaining amount of alkali metal hydroxide is added slowly with stirring, at least part, preferably the still missing amount of alkali metal hydroxide, being added as a solid. The addition is preferably accomplished by stirring the NaOH and/or KOH granules.

Temperature maximum 40°C, preferably maximum 35°C for addition steps d) to h):

From stage d) the aqueous phase can no longer reach a temperature that exceeds 40°C. The inventors of the present invention have discovered that steps d) to h) must be carried out at temperatures that are in the range between 15°C and a maximum of 40°C in order to obtain a stable suspension with the above properties. In the temperature range from 15 to 35°C, there was no effect of temperature on the stability and viscosity of the suspension. At elevated temperatures, the solubility of NaOH and/or KOH increases increasingly. However, when the temperatures during addition exceeded 40°C, it was no longer possible to obtain a stable, dosed suspension, since the detergent concentrate after cooling had a paste-like consistency.

In addition, it was found that the suspension obtained according to the invention, when heated to temperatures above 60° C. after cooling, thickened irreversibly, which is explained by a harmful effect on the suspension.

Temperature control can be achieved, for example, by cooling (eg a cooling jacket), or by running the process appropriately slowly. In step d), for example, it is useful to mix in a ready-made alkali metal hydroxide solution, thereby not causing a noticeable increase in temperature.

Preferably, active external cooling is provided (eg by means of a cooling jacket).

A stirrer, for example an anchor stirrer, may be provided to obtain the suspension.

In one embodiment, a dispersant is additionally prepared to speed up the formation of the suspension.

The inventors of the present invention have surprisingly discovered that for two reasons it is advantageous to admix at least partly KOH as an alkali metal hydroxide into the composition. In principle, a specialist gives preference to NaOH over KOH for various reasons:

KOH is more expensive than NaOH. Moreover, the cleaning performance of a pure KOH solution for cleaning dishes is (slightly) worse than the cleaning performance of a pure NaOH solution. Additionally, KOH is known to react more vigorously with CO2 from the air than NaOH and form carbonates in solution (scale formation). Finally, the dissolution process of pure KOH is more exothermic (enthalpy of dissolution -57.1 kJ/mol) compared to NaOH (enthalpy of dissolution -44.5 kJ/mol), which, in principle, would make the use of KOH unacceptable for a specialist when in aqueous phase needs to be kept at a low temperature.

- 4 044448

However, within the framework of the present invention, its authors discovered that the absorption of CO2 when mixing KOH leads to less scale formation than when adding pure NaOH. The formation of scale is undesirable, since the suspension is supplied to the pump through the suction tube, and scale can clog the suction tube. Therefore, the presence of KOH is preferable.

Although the KOH dissolution process is in principle more exothermic, it appears that when KOH granules are added in step f), the spontaneous temperature rise is less than when NaOH granules are added, so that the process can be more easily controlled.

With regard to the composition of the liquid washing concentrate, which is a suspension, it was possible to establish the following:

i) from 22 to 46 wt.% alkali metal hydroxide.

Dish detergents show better cleaning performance at high concentrations of alkali metal hydroxide. For this invention it was possible to mix up to 46 wt.% alkali metal hydroxide, with which a stable suspension was achieved, the viscosity of which was maintained in the above range.

From the above considerations, NaOH (22 to 46 wt%), KOH (22 to 46 wt%), or mixtures thereof (NaOH: 25 to 46 wt% - x wt%; KOH: x wt) are preferred. .%).

The highest suspension stability was achieved with the mixture

NaOH and KOH, in which the KOH content is between 5 and 10 wt.%;

ii) from 5 to 50 wt.% dispersant _g complexing agent or a combination thereof.

Particularly good cleaning performance by the detergent has been achieved when at least one dispersant and at least one complexing agent are present in the detergent concentrate. Particularly preferably, the dispersant includes a polymeric dispersant. A preferred detergent concentrate contains from 1 to 10% by weight of a polymeric dispersant.

In one preferred embodiment, it has proven advantageous when the complexing agent has an organic amine functionality, preferably being selected from the group consisting of aminocarboxylic acids, aminophosphonic acids, or combinations thereof. In this way it was possible to obtain a particularly effective liquid detergent concentrate.

It has proven advantageous when the polymeric dispersant is a polycarboxylic acid, preferably polyacrylic acid or a derivative thereof;

ii i) from 0 to 5 wt.% surfactant.

The surfactant content, due to foaming ability and stability, as well as cost and environmental considerations, cannot be too high. Amounts of up to 2% by weight are preferably used, in particular preferably from 0.5 to 1.5% by weight. Surfactants generally known for dishwashing detergents can be used. But in one embodiment it has proven advantageous when the surfactant is a nonionic surfactant, preferably an aliphatic alcohol alkoxylate or derivative thereof. An aliphatic alcohol alkoxylate 8 (Plurafac LF 400, BASF) has proven to be a particularly suitable surfactant;

iv) from 0 to 5 wt.% auxiliary additives.

With regard to auxiliary additives, reference can be made to the above-mentioned embodiments. Preferably, amounts between 1 and 3 wt.% of the auxiliary additive are added. In this case, monoethanolamine is particularly preferably added;

v) from 28 to 39 wt.% water.

The water content is preferably between 28 and 39% by weight, with concentrations below 28% by weight no longer providing the desired viscosities. Although at concentrations above 39 wt.% a suspension can be obtained, it is true that then the advantage compared to a solution is no longer very great.

In one embodiment, it is provided that the liquid detergent concentrate does not contain ethanol, glycerin and other short-chain alcohols (alcohols from C ₁ to C ₅ ), since such alcohols have been found to increase viscosity, that is, act as thickeners. It has also been shown that the introduction of solutions of NaOH in alcohols, polyols or glycerin with the addition of solid NaOH leads to uncontrolled hardening and non-uniform thickening.

In one preferred embodiment, the cleaning concentrate does not have components other than those listed above.

Experimental results and example execution.

The liquid detergent concentrate presented above is a stable suspension and has such a viscosity that it can be pumped by the dosing device and thus dosed. It is therefore preferably provided that the viscosity of the cleaning concentrate has a value of maximum 6500 mPa-s, measured according to ISO 2555:1989 at a temperature of 20°C with a rotation speed of 5 rpm.

Examples.

- 5 044448

The following shows exemplary compositions, as well as a method for producing detergent concentrates corresponding to the invention, as well as their rheological characteristics, and in comparison comparative examples that do not correspond to the invention.

Example 1 Example according to the invention

Component Proportion of starting material ¹ Proportion of component ² [wt.%] Function Stage

[weight.%] Trisodium salt of Ν,Νcarboxymethylalanine ³ ' in aqueous solution (40 wt.%) 27.0 10.8 TO A) Aminophosphonic acid salt ⁴ ' in aqueous solution (42 wt.%) 100 4.2 TO Monoethanolamine 2.2 2.2 N b) Polymeric phosphonic acid ⁵ '; hydrochloric acid; in aqueous solution (60 wt.%) 5.0 thirty TO With) Soda lye (50 weight.%) 22.3 11.15 HON d) Isotridecanol ethoxylate ⁶ ' 1.5 1.5 T e) Potassium hydroxide 100 10.0 HON f) g) Polyacrylic acid ⁹ ', sodium salt (in aqueous solution, 55 wt.%) 3.0 1.65 TO Sodium hydroxide 19, 0 19.0 HON h) Generally 100 63.5

¹¹ Water-containing component ²⁾ Pure component (not containing water) ³¹ Trilon M fl., ⁴⁾ Dequest 2066 ⁵¹ Hydrodis WP 40 ⁶¹ Lutensol TO 7 ⁹⁾ Sokalan PA 30 CL (aqueous solution)

K Complexing agent/dispersant

N Auxiliary additive

T Surfactant

HON Alkali metal hydroxide

Stage. Stage of the method according to paragraph 10 of the claims.

The total water content is 36.5 wt%. During the preparation process, cooling was carried out so that the maximum temperature of 35°C was not exceeded. The viscosity of the suspension was:

Viscosity (mPa-s): 4500 mPa-s, measured according to ISO 2555:1989 at 20°C and 5 rpm.

- 6 044448

Example 2 Example according to the invention.

Component Proportion of starting material ¹ [wt.%] Proportion of component ² [wt.%] Function Stage Trisodium salt of Ν,Νcarboxymethylalanine ³ ' in aqueous solution (40 wt.%) 27.0 10.8 TO A) Aminophosphonic acid salt ⁴ ' in aqueous solution (42 wt.%) 100 4.2 TO Monoethanolamine 2.2 2.2 N b) Polymeric phosphonic acid ⁵ '; hydrochloric acid; in aqueous solution (60 wt.%) 5.0 thirty TO With) Soda lye (50 weight.%) 22.3 11.15 HON d) Canol iso tride ethoxylate ⁶ ' 0.5 0.5 T e) Potassium hydroxide 8.0 8.0 HON f) g) Polyacrylic acid ⁹ ', sodium salt (in aqueous solution, 55 wt.%) 5.0 2.75 To Sodium carbonate mixture ⁸ ', no phosphate 1.0 10 n g) Sodium hydroxide 19, 0 19.0 hon. h) Generally 100 62.6

¹¹ Water containing component ²⁾ Pure component (not containing water) ³⁾ Tri Ion M, liquid ⁴⁾ Dequest 2066 ⁵¹ Hydrodis WP 40 ⁶¹ Lutensol TO 7 ⁷¹ Sokalan PA 25 CL, granules ⁸⁾ Mirapol Surf S ⁹⁾ Sokalan PA 30 CL (aqueous solution)

K Complexing agent/dispersant

N Auxiliary additive

T Surfactant

HON Alkali metal hydroxide

The total water content is 37.4 wt%. During the preparation process, cooling was carried out so that the maximum temperature of 35 °C was not exceeded. The viscosity of the suspension was:

Viscosity (mPa-s): 6000 mPa-s, measured according to ISO 2555:1989 at 20°C and 5 rpm.

- 7 044448

Example 3. Example according to the invention.

Component Proportion of starting material ¹ [wt.%] Proportion of component ² [wt.%] Function Stage Trisodium salt of Ν,Νcarboxymethylalanine ³ ' in aqueous solution (40 wt.%) 27.0 10.8 TO A) Aminophosphonic acid salt ⁴ ' in aqueous solution (42 wt.%) 100 4.2 TO Monoethanolamine 2.2 2.2 N b) Polymeric phosphonic acid ⁵ '; hydrochloric acid; in aqueous solution (60 wt.%) 5.0 thirty TO With) Soda lye (50 weight.%) 22.3 11.15 HON d) Ethoxylate 1.5 1.5 T e)

iso tride canol a ⁶ ' Potassium hydroxide 8.0 8 HON f) g) Polyacrylic acid ⁹ ', sodium salt (in aqueous solution, 55 wt.%) 5.0 2.75 TO Sodium hydroxide 19, 0 19.0 HON h) Generally 100 62.6

¹¹ Water containing component ²¹ Pure component (not containing water) ³⁾ Trilon M, liquid, ⁴⁾ Dequest 2066 ⁵¹ Hydrodis WP 40 ⁶¹ Lutensol TO 7 ⁹⁾ Sokalan PA 30 CL, aqueous solution ⁸¹ Mirapol Surf S

K Complexing agent

N Auxiliary additive

T Surfactant

CHON Alkali metal hydroxide.

The total water content is 37.4 wt%. During the preparation process, cooling was carried out so that the maximum temperature of 35°C was not exceeded. The viscosity of the suspension was:

Viscosity (mPa-s): 3800 mPa-s, 20°C, measured according to ISO 2555:1989 at 20°C and 5 rpm.

Comparative example 1.

Component Proportion of starting material ¹ [wt.%] Proportion of component ² [wt.%] Function Stage Water 35.0 - L.M. 1 Polymeric phosphonic acid ³ ' in aqueous solution (50 wt.%) 10.0 5.0 TO 2 Glycerol 5.0 5.0 TO 3

- 8 044448

Potassium hydroxide 10.0 100 HON 4 Polyacrylic acid, sodium salt ⁴ 20.0 20, 0 TO 5 Sodium hydroxide 20.0 20, 0 HON 6

Overall 100.0 60.0 ⁴⁾ Water-containing component ²⁾ Pure component (water-free) ³ > Hydrodis ADW 3814/N ⁴⁾ Sokalan PA 25 CL, granules

K Complexing agent

LM Solvent

HON Alkali metal hydroxide

The total water content is 40.0 wt.%.

When preparing the concentrate of Comparative Example 1, no temperature control was provided. During the production process, the maximum temperature reached 75°C. Immediately after production, the concentrate was highly viscous; after 24 hours the composition was gel-like. The presence of glycerol could have a negative effect on viscosity stability.

Comparative example 2.

Component Proportion of starting material ¹ [wt.%] Proportion of component ² [wt.%] Function Stage Trisodium salt of N,Ncarboxymethylalanine ³¹ in aqueous solution (40 wt.%) 27.7 11.1 TO A) Aminophosphonic acid salt ⁴ ' in aqueous solution (42 wt.%) 10 4.2 TO Monoethanolamine 2.2 2.2 N b) Polymeric phosphonic acid ⁵ '; hydrochloric acid; in aqueous solution (60 wt.%) 5 3 TO With) Soda lye (50 weight.%) 22 11.0 HON d) Sodium carbonate based mixture ⁶ ', no phosphate 0.8 0.8 N e) Potassium hydroxide 7.5 7.5 HON G) d) Polyacrylic acid ⁷ ', sodium salt 5.8 5.8 TO Sodium hydroxide 19 19.0 HON h) Generally 100 64.6

¹¹ Water containing component ²¹ Pure component (not containing water) ³⁾ Trilon M, liquid, ⁴⁾ Dequest 2066 ⁵⁾ Hydrodis WP 40 ⁶¹ Mirapol Surf S ⁷⁾ Sokalan PA 30 CL, granules

K Complexing agent

N Auxiliary additive

CHON Alkali metal hydroxide

Total water content: 35.4 wt%.

Claims (11)

The composition does not contain surfactants. The composition without temperature control upon receipt turned out to be viscous. With temperature control during the production process (maximum temperature 35°C), the viscosity of the suspension was still in the range of 6500 mPa-s. The complete absence of surfactants did indeed have a negative effect on viscosity. Addition of 0.5 wt.% shows a decrease in viscosity and an increase in stability. Reducing the water content in water-based detergent concentrates generally leads to an increase in viscosity. Patent document DE 100 02 710 A1 describes a creamy detergent concentrate with a water content of 32.5%. True, such a state as a cream or paste, due to its high viscosity, is unfavorable for use in automatic dispensers. Such a cleaning concentrate could not be dosed by a peristaltic hose pump in the dosing device. The detergent concentrate obtained by the method according to the invention has two differences from cream or paste detergents according to the patent document DE 100 02 710 A1: firstly, in the patent document DE 100 02 710 A1 a homogeneous mixture without particles is obtained, that is, not a suspension. Secondly, the cleaning concentrate according to patent document DE 100 02 710 A1 has a significantly higher viscosity, which leads to poor dosageability. In the following table. 1 compares the cleaning concentrate according to the invention and the cleaning concentrate according to patent document DE 100 02 710 A1. Table 1 Comparison of viscosity of detergent concentrates Composition of Example 1 Example according to DE 100 02 710 A1 Viscosity (mPa - s)* 2671+/-35 From 20000 to 90000 (suspension) (creamy paste) *Measuring conditions as in patent document DE 100 02 710 A1: Brookfield viscometer according to ISO 2555:1989. The results of single measurements for example 1 were as follows. Result of Example 1 Viscosity, mPa-s Dimension 1 2651 Dimension 2 2711 Dimension 3 2651 Additionally, the composition according to Example 3 was obtained under different conditions, that is, at different temperatures. Addition steps d) to h) were carried out so that the temperature in the aqueous phase did not exceed 40°C (see Table 2). table 2 Viscosity comparison - composition according to example 3 Results: Viscosity (mPa-s) at 5 rpm, 20°C* Sample 1 2184 Sample 2 6360 Sample 3 2400 Sample 4 3030 *Measurement conditions: Brookfield viscometer according to ISO 2555:1989. In samples 1, 3 and 4, the maximum temperature was 35°C; for sample 2 it briefly reached 40°C. The measured values correlate with the maximum temperature achieved, that is, for sample 1 the lowest temperatures occurred, for sample 2 the highest. CLAIM 1. Liquid detergent concentrate comprising (i) from 22 to 46 wt.% alkali metal hydroxide, (ii) from 5 to 50 wt.% dispersant, complexing agent or combination thereof, (iii) from 0.5 to 1.5 wt. .% surfactant, and (v) from 28 to 39% by weight water, the detergent concentrate being a suspension, the viscosity of the suspension being a maximum of 6500 mPa-s, measured according to ISO 2555:1989 at a temperature of 20° C with a rotation speed of 5 rpm. 2. Liquid detergent concentrate according to claim 1, additionally containing (iv) up to 5 wt.% auxiliary additive. - 10 044448 3. Liquid detergent concentrate according to claim 1 or 2, characterized in that the alkali metal hydroxide is sodium hydroxide, potassium hydroxide or a mixture thereof. 4. Liquid detergent concentrate according to claim 3, characterized in that it contains from 20 to 41 wt.% sodium hydroxide and from 5 to 10 wt.% potassium hydroxide. 5. Liquid detergent concentrate according to one of claims 1-4, characterized in that the concentrate includes a combination of at least a complexing agent and a polymer dispersant. 6. Liquid washing concentrate according to claim 5, characterized in that it contains from 5 to 49 wt.% complexing agent and from 1 to 10 wt.% polymer dispersant. 7. Liquid detergent concentrate according to claim 5 or 6, characterized in that the complexing agent has an organic amine functional group, and is preferably selected from the group consisting of aminocarboxylic acids, aminophosphonic acids and combinations thereof. 8. Liquid detergent concentrate according to one of claims 5-7, characterized in that the polymer dispersant is a polycarboxylic acid, preferably polyacrylic acid or a derivative thereof. 9. Liquid detergent concentrate according to one of claims 2-8, characterized in that the auxiliary additive is monoethanolamine. 10. A method of producing a suspension comprising (i) from 22 to 46 wt.% alkali metal hydroxide, (i) from 5 to 50 wt.% dispersant, complexing agent or combination thereof, (iii) from 0.5 to 1.5 wt. .% surfactant, (iv) from 0 to 5 wt.% auxiliary additives, and (y) from 28 to 39 wt.% water, the method comprising the steps of: a) preparing a portion of a dispersant, complexing agent or a combination thereof in an aqueous solution, b) if necessary, adding auxiliary additives, c) in case of adding auxiliary additives, then adding an additional portion of dispersant, d) adding a portion of alkali metal hydroxide in the form of an aqueous solution, f) adding a surfactant, f) adding an additional portion of alkali metal hydroxide in the form of a solid, g) adding a dispersant, h) adding an additional portion of alkali metal hydroxide, wherein the addition steps are carried out with stirring, and at least the addition steps d) to h) are carried out in such a way that the aqueous phase is maintained at a temperature of from 15 to 40°C. 11. The method according to claim 10, characterized in that the temperature in the aqueous phase is maintained at no higher than 35°C. Eurasian Patent Organization, EAPO Russia, 109012, Moscow, Maly Cherkassky lane, 2