LIQUID CLEANING CONCENTRATE

Abstract

A detergent concentrate comprising (i) 22 to 46% by weight alkaline metal hydroxide, (ii) 5 to 50% by weight dispersing agent, chelating agent or a combination thereof, (iii) 0 to 5% by weight tenside, (iv) 0 to 5% by weight excipients and (v) 28 to 39% by weight water, wherein the detergent concentrate is a suspension; as well as methods of production therefor.

Claims

1. A detergent concentrate comprising (i) 22 to 46% by weight alkaline metal hydroxide, (ii) 5 to 50% by weight dispersing agent, chelating agent or a combination thereof, (iii) 0 to 5% by weight tenside, (iv) 0 to 5% by weight excipients and (v) 28 to 39% by weight water, wherein the detergent concentrate is a suspension.

2. A detergent concentrate according to claim 1, wherein the suspension has a viscosity of at the most 6500 mPa.Math.s, measured according to ISO 2555:1989 at 20 C. at a rotational speed of 5 rpm.

3. A detergent concentrate according to claim 1, wherein the alkaline metal hydroxide is sodium hydroxide, potassium hydroxide, or a mixture thereof.

4. A detergent concentrate according to claim 3, wherein the detergent concentrate comprises: 20 to 41% by weight sodium hydroxide and 5 to 10% by weight potassium hydroxide.

5. A detergent concentrate according to claim 1, wherein the dispersing agent comprises at least a chelating agent and polymeric dispersing agent.

6. A liquid detergent concentrate according to claim 5, wherein the detergent concentrate comprises: 5 to 49% by weight chelating agent and 1 to 10% by weight polymeric dispersing agent.

7. A liquid detergent concentrate according to claim 5, wherein the chelating agent has an organic amino function.

8. A liquid detergent concentrate according to claim 4, wherein the polymeric dispersing agent is a polycarboxylic acid.

9. A liquid detergent concentrate according to claim 1, wherein the excipient is monoethanol amine.

10. A method for producing a suspension, comprising (i) 22 to 46% by weight alkaline metal hydroxide, (ii) 5 to 50% by weight dispersing agent, chelating agent or a combination thereof, (iii) 0 to 5% by weight tenside, (iv) 0 to 5% by weight excipients and (v) 28 to 39% by weight water, wherein the method comprises the following steps: a) providing a portion of a dispersing agent, chelating agent or a combination thereof in an aqueous solution, b) optionally adding excipients, c) in the case of the addition of excipients, subsequently adding a further portion of a dispersing agent, d) adding a portion of an alkaline metal hydroxide as an aqueous solution, e) optionally adding a tenside, f) adding a portion of an alkaline metal hydroxide as a solid, g) adding a dispersing agent, h) adding a further portion of an alkaline metal hydroxide, wherein the steps of adding are carried out while stirring and wherein at least the addition steps d) to h) are carried out such that in the aqueous phase there is maintained a temperature of at most 40 C.

11. A liquid detergent concentrate according to claim 7, wherein the chelating agent is selected from the group consisting of amino carboxylic acids, amino phosphonic acids, and combinations thereof.

12. A liquid detergent concentrate according to claim 8, wherein the polymeric dispersing agent is a polyacrylic acid or a derivative thereof.

13. The method according to claim 10, wherein at least the addition steps d) to h) are carried out such that in the aqueous phase there is maintained a temperature of at most 40 C.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0064] In the following, further advantages and details of the invention are explained. The explanations relate to the liquid detergent concentrate and the production method for the suspension likewise. Due to considerations regarding the better understanding thereof, the production method is the first to be described in greater detail.

Step a) Providing a Portion of a Dispersing Agent, Chelating Agent or a Combination Thereof in an Aqueous Solution:

[0065] First, there is provided a solution of a dispersing agent, chelating agent or a combination thereof in water.

[0066] There is preferably provided a mixture of a first and a second chelating agent.

[0067] A first chelating agent may, for example, be selected from the group of the amino carboxylic acids, and a second chelating agent may be selected from the group of the amino phosphonic acids.

[0068] In a first embodiment variant, in step a) there may be provided a mixture of an aqueous solution of the first chelating agent (such as an amino carboxylic acid, more preferred an methyl glycine di-acetic acid or a salt thereof), and an aqueous solution of a second chelating agent (such as an amino phosphonic acid, more preferred an diethylene triamine pentamethylene phosphonic acid or a salt thereof).

Step b) Optionally Adding Excipients,

[0069] In step b), there may be added excipients.

Step c) Adding a Further Portion of a Dispersing Agent:

[0070] If excipients are added, then it is advantageous to add a further portion of a dispersing agent in a subsequent step. The addition of excipients and the subsequent addition of dispersing agents will lead to a more stable suspension.

Step d) Adding a Portion of an Alkaline Metal Hydroxide as an Aqueous Solution:

[0071] In step d), a first addition of alkaline metal hydroxide is carried out while stirring, namely as an aqueous solution. Based on the total amount of alkaline metal hydroxide, in this step there is preferably added less than the half, in particular preferably less than a third of the final amount of alkaline metal hydroxide.

[0072] As aqueous solutions there may preferably be used such of NaOH or KOH, wherein there is no difference whether there is used an NaOH solution or a KOH solution and whether an NaOH solution and a KOH solution are added separately or if there is added an NaOH/KOH mixture. There are also possible any combinations thereof.

Step e) Adding a Tenside:

[0073] In step e), there is added a tenside while stirring.

Step f) Adding a Portion of an Alkaline Metal Hydride:

[0074] In step f), there is added a further portion of an alkaline metal hydride as a solid. The addition is preferably carried out by adding NaOH and/or KOH pellets while stirring.

Step g) Adding a Further Portion of a Dispersing Agent:

[0075] In step g), there is carried out the addition of a further portion of a dispersing agent, which is introduced while stirring.

Step h) Adding a Further Portion of an Alkaline Metal Hydroxide:

[0076] In step h), there is slowly added the still lacking amount of alkali metal hydroxide while stirring, wherein at least a part, preferably the entire amount of alkaline metal hydroxide still lacking, is added as a solid. The addition is preferably carried out by introducing NaOH and/or KOH pellets while stirring.

Temperature at the Most 40 C., Preferably at the Most 35 C. for the Addition Steps d) to h):

[0077] From step d) on, the aqueous phase must not reach a temperature exceeding 40 C. The inventors have found that the steps d) to h) have to be carried out at temperatures in the range between 15 C. and at the most 40 C. in order to obtain a stable suspension having the properties mentioned above. In the temperature range of 15 to 35 C., there was not exhibited an influence of the temperature on the stability and viscosity of the suspension. With increasing temperatures, the solubility of NaOH and/or KOH will increase gradually. If, however, the temperatures were above 40 C. during the addition, then it was not possible to obtain a stable, meterable suspension, as the detergent concentrate did have a paste-like consistence upon cooling.

[0078] Further it has been shown that the suspension prepared according to the invention thickened irreversibly upon cooling after heating to temperatures above 60 C., which is to be ascribed to a disadvantageous impairment of the suspension.

[0079] Temperature control can be achieved, for example, by way of cooling (e.g., using a cooling collar) or by a correspondingly slow process control. In step d), it may be useful to add an already finished solution of alkaline metal hydroxide such that no noteworthy increase in temperature will occur.

[0080] There is preferably provided an active external cooling (e.g., cooling collar).

[0081] For the preparation of the suspension there may be provided a stirrer, for example an anchor stirrer.

[0082] In an embodiment variant, there is additionally provided a dispersing means in order to accelerate the formation of a suspension.

[0083] The inventors have surprisingly found that it is advantageous for two reasons to add at least in part KOH as alkaline metal hydroxide to the composition. Basically, the person skilled in the art will prefer NaOH to KOH for various reasons:

[0084] In comparison with NaOH, KOH is more expensive. Furthermore, the cleaning performance of a pure KOH solution for cleaning dishes is (slightly) worse than the cleaning performance of a pure NaOH solution. Furthermore, KOH has been known for having a stronger reaction with CO.sub.2 from air than NaOH and for carbonates being formed in the solution (formation of deposits). Finally, pure KOH has a stronger exothermic action in the dissolution process (solution enthalpy57.1 kJ/mol) than NaOH (solution enthalpy44.5 kJ/mol), which would in principle discourage any person skilled in the art to use KOH if a lower temperature is to be maintained in the aqueous phase.

[0085] Within the scope of the invention the inventors, however, have found out that the ingestion of CO.sub.2 when adding KOH will lead to less formation of deposits than when using pure NaOH. The formation of deposits is undesired as the suspension is conveyed to the pump via a suction lance and the deposits may obstruct the suction lance. For this reason, the presence of KOH is preferred.

[0086] In spite of a fundamentally higher exothermic action upon dissolution of KOH it has been shown that, when KOH pellets are added in step f), the spontaneous increase in temperature was less than with the addition of NaOH pellets such that it is easier to control the process.

[0087] In regard to the composition of the liquid detergent concentrate, which is a suspension, there could be gained the following findings:

(i) 22 to 46% by Weight Alkaline Metal Hydroxide:

[0088] Dish detergents exhibit the best cleaning performance at high concentrations of alkaline metal hydroxide. For the present invention, an addition of up to 46% by weight of alkaline metal hydroxide was possible, by means of which a stable suspension could be obtained, the viscosity of which being within the range mentioned.

[0089] Due to the reasons mentioned above, NaOH (22 to 46% by weight), KOH (22 to 46% by weight) or mixtures thereof (NaOH: 25 to 46% by weightx % by weight; KOH: x % by weight) are preferred.

[0090] The highest stability of the suspension was obtained using a mixture of NaOH and KOH, wherein the content of KOH was between 5 and 10% by weight.

(ii) 5 to 50% by Weight Dispersing Agent, Chelating Agent or a Combination Thereof:

[0091] An especially good cleaning activity of the detergent was obtained when there are present in the detergent concentrate at least one dispersing agent and at least one chelating agent. Especially preferably, the dispersing agent comprises a polymeric dispersing agent. A preferred detergent concentrate comprises 1 to 10% by weight of a polymeric dispersing agent.

[0092] In a preferred embodiment variant, it has proven to be advantageous if the chelating agent has an organic amino function and is preferably selected from the group including amino carboxylic acids, amino phosphonic acids or a combination thereof. In this way, it was possible to produce especially advantageously a liquid detergent concentrate.

[0093] It has proven to be advantageous if the polymeric dispersing agent is a polycarboxylic acid, preferably polyacrylic acid or a derivative thereof.

(iii) 0 to 5% by Weight Tenside:

[0094] The proportion of tensides must not be too high due to the foaming behaviour and the stability as well as due to cost-effective and environmental reasons. There are preferably used up to 2% by weight, especially preferred 0.5 to 1.5% by weight. As such, there may be used well-known tensides for dish detergents. In an embodiment variant, however, it has proven to be advantageous if the tenside does not represent a non-ionic tenside but rather preferably a fatty alcohol alkoxylate or a derivative thereof. Fatty alcohol alkoxylate 8 (Plurafac LF 400, company BASF) has been shown to be an especially suitable tenside.

(iv) 0 to 5% by Weight Excipients:

[0095] For the excipients, there may be made reference to the explanations given above. There are preferably used between 1 and 3% by weight of excipient. Monoethanol amine is especially preferably added.

(v) 28 to 39% by Weight Water:

[0096] The water content is preferably 28 to 39% by weight, wherein concentrations below 28% by weight did not have the desired viscosities any longer. Concentrations above 39% by weight may be produced as suspensions, but the advantage over a solution will not be very great, however.

[0097] In an embodiment variant there is provided that the liquid detergent concentrate is free of ethanol, glycerine and other short-chain alcohols (C.sub.1- to C.sub.5 alcohols), as it has been shown that such alcohols will increase the viscosity, i.e. act as thickening agents. It has been also shown that the introduction of NaOH solutions into alcohols, polyols or glycerine while adding solid NaOH will lead to uncontrollable curing and an inhomogeneous thickening.

[0098] In a preferred embodiment variant, the detergent concentrate has no further ingredients but those mentioned above.

Experiment Results and Embodiment Example

[0099] The liquid detergent concentrate represented above is a stable suspension and has a viscosity such that it may be pumped in a metering device, thus being meterable. For this reason, there is preferably provided that the viscosity of the detergent concentrate is at the most 6500 mPa.Math.s, measured according to ISO 2555:1989 at 20 C. at a rotational speed of 5 rpm.

EXAMPLES

[0100] In the following, there are shown as examples formulations as well as methods of production for detergent concentrates according to the invention as well as the rheological properties thereof, in a comparison with comparative examples that are not according to the invention.

Example 1: Example According to the Invention

[0101]

TABLE-US-00001 Proportion Proportion raw ingre- material.sup.1 dient.sup.2 [% by [% by Ingredient weight] weight] Function Step Alanine N,N-carboxymethyl- 27.0 10.8 K a) trisodium salt.sup.3) in aqueous solution (40% by weight) Amino phosponic acid salt.sup.4) in 10.0 4.2 K aqueous solution (42% by weight) Monoethanol amine 2.2 2.2 H b) Polymeric phosphonic acid.sup.5); 5.0 3.0 K c) hydrochloric acid; in aqueous solution (60% by weight) Caustic soda (50% by weight) 22.3 11.15 XOH d) Isotridecanol ethoxylate.sup.6) 1.5 1.5 T e) Potassium hydroxide 10.0 10.0 XOH f) Polyacrylic acid.sup.9), sodium salt 3.0 1.65 K g) (in aqueous solution, 55% by weight) Sodium hydroxide 19.0 19.0 XOH h) Total 100 63.5 .sup.1ingredient including water .sup.2pure ingredient (free of water) .sup.3)Trilon M, aqu. .sup.4)Dequest 2066 .sup.5)Hydrodis WP 40 .sup.6)Lutensol TO 7 .sup.9)Sokalan PA 30 CL (aqueous solution). K chelating agent/dispersing agent H excipient T tenside XOH alkaline metal hydroxide Step method step according to claim 10

[0102] The total water content is 36.5% by weight. In the production process, there was carried out cooling such that the maximum temperature did not exceed 35 C. The viscosity of the suspension was:

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

Example 2: Example According to the Invention

[0103]

TABLE-US-00002 Proportion Proportion raw ingre- material.sup.1 dient.sup.2 [% by [% by Ingredient weight] weight] Function Step Alanine N,N-carboxymethyl- 27.0 10.8 K a) trisodium salt.sup.3) in aqueous solution (40% by weight) Amino phosponic acid salt.sup.4) in 10.0 4.2 K aqueous solution (42% by weight) Monoethanol amine 2.2 2.2 H b) Polymeric phosphonic acid.sup.5); 5.0 3.0 K c) hydrochloric acid; in aqueous solution (60% by weight) Caustic soda (50% by weight) 22.3 11.15 XOH d) Isotridecanol ethoxylate.sup.6) 0.5 0.5 T e) Potassium hydroxide 8.0 8.0 XOH f) Polyacrylic acid.sup.9), sodium salt 5.0 2.75 K g) (in aqueous solution, 55% by weight) Mixture on the basis of 1.0 1.0 H g) sodium carbonate.sup.8); without phosphate Sodium hydroxide 19.0 19.0 XOH h) Total 100 62.6 .sup.1ingredient including water .sup.2pure ingredient (free of water) .sup.3)Trilon M, aqu. .sup.4)Dequest 2066 .sup.5)Hydrodis WP 40 .sup.6)Lutensol TO 7 .sup.7)Sokalan PA 25 CL (granula) .sup.8)Mirapol Surf S .sup.9)Sokalan PA 30 CL (aqu. solution) K chelating agent/dispersing agent H excipient T tenside XOH alkaline metal hydroxide

[0104] The total water content is 37.4% by weight. In the production process, there was carried out cooling such that the maximum temperature did not exceed 35 C. The viscosity of the suspension was:

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

Example 3: Example According to the Invention

[0105]

TABLE-US-00003 Proportion Proportion raw ingre- material.sup.1 dient.sup.2 [% by [% by Ingredient weight] weight] Function Step Alanine N,N-carboxymethyl- 27.0 10.8 K a) trisodium salt.sup.3) in aqueous solution (40% by weight) Amino phosponic acid salt.sup.4) in 10.0 4.2 K aqueous solution (42% by weight) Monoethanol amine 2.2 2.2 H b) Polymeric phosphonic acid.sup.5); 5.0 3.0 K c) hydrochloric acid; in aqueous solution (60% by weight) Caustic soda (50% by weight) 22.3 11.15 XOH d) Isotridecanol ethoxylate.sup.6) 1.5 1.5 T e) Potassium hydroxide 8.0 8 XOH f) Polyacrylic acid.sup.9), sodium salt 5.0 2.75 K g) (in aqueous solution, 55% by weight) Sodium hydroxide 19.0 19.0 XOH h) Total 100 62.6 .sup.1ingredient including water .sup.2pure ingredient (free of water) .sup.3)Trilon M, aqu. .sup.4)Dequest 2066 .sup.5)Hydrodis WP 40 .sup.6)Lutensol TO 7 .sup.9)Sokalan PA 30 CL aqueous solution .sup.8)Mirapol Surf S K chelating agent H excipient T tenside XOH alkaline metal hydroxide

[0106] The total water content is 37.45% by weight. In the production process, there was carried out cooling such that the maximum temperature did not exceed 35 C. The viscosity of the suspension was:

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

Comparative Example 1

[0107]

TABLE-US-00004 Proportion Proportion ingredient.sup.2 raw material.sup.1 [% by Ingredient [% by weight] weight] Function Step Water 35.0 LM 1 Polymeric phosphonic 10.0 5.0 K 2 acid in aqueous solution (50% by weight) Glycerol 5.0 5.0 K 3 Potassium hydroxide 10.0 10.0 XOH 4 Polyacrylic acid, 20.0 20.0 K 5 sodium salt.sup.4) Sodium hydroxide 20.0 20.0 XOH 6 Total 100 60.0 .sup.1ingredient including water .sup.2pure ingredient (free of water) .sup.3)Hydrodis ADW 3814/N .sup.4)Sokalan PA 25 CL (granula) K chelating agent LM solvent XOH alkaline metal hydroxide

[0108] The total water content is 40.0% by weight.

[0109] In the preparation of the concentrate of comparative example 1, there was not provided any temperature control. In the production process, the temperature was 75 C. at the most. Already immediately after preparation, the concentrate was highly viscous; after 24 hours, the composition was gel-like. The presence of glycerol seems to have a negative effect on the stability of the viscosity.

Comparative Example 2

[0110]

TABLE-US-00005 Proportion Proportion raw ingre- material.sup.1 dient.sup.2 [% by [% by Ingredient weight] weight] Function Step Alanine N,N-carboxymethyl- 27.0 11.1 K a) trisodium salt.sup.3) in aqueous solution (40% by weight) Amino phosponic acid salt.sup.4) in 10.0 4.2 K aqueous solution (42% by weight) Monoethanol amine 2.2 2.2 H b) Polymeric phosphonic acid.sup.5); 5 3 K c) hydrochloric acid; in aqueous solution (60% by weight) Caustic soda (50% by weight) 22 11.0 XOH d) Mixture on the basis of 0.8 0.8 H e) sodium carbonate.sup.6); without phosphates Potassium hydroxide 7.5 7.5 XOH f) Polyacrylic acid.sup.7), sodium salt 5.8 5.8 K g) Sodium hydroxide 19 19.0 XOH h) Total 100 64.6 .sup.1ingredient including water .sup.2pure ingredient (free of water) .sup.3)Trilon M, aqu. .sup.4)Dequest 2066 .sup.5)Hydrodis WP 40 .sup.6)Mirapol Surf S .sup.7)Sokalan PA 25 CL granule K chelating agent H excipient XOH alkaline metal hydroxide

[0111] Total water content: 35.4% by weight.

[0112] The preparation is free of tensides. The formulation was too viscous without any temperature control during preparation. Using temperature control in the production method (maximum temperature of 35 C.), the viscosity of the suspension was still in the range of 6500 mPa.Math.s. The complete absence of tensides, however, had a negative effect on the viscosity. An addition of 0.5% by weight showed a reduction of viscosity and an increase of stability.

[0113] A reduction of the water content in detergent concentrates on the basis of water usually results in an increase in viscosity. In the DE 100 02 710 A1 there is described a cream-like detergent concentrate having a water proportion of 32.5%. The property as a cream or paste, however, is unsuitable for the use in metering device due to the high viscosity. Such a detergent could not be metered using a pinch pump in the metering device.

[0114] A detergent concentrate prepared according to the method according to the invention shows two differences to the cream- or paste-like detergents according to the DE 100 02 710 A1: Firstly, in the DE 100 02 710 A1 there is prepared a homogenous mixture without particles, i.e. no suspension. Secondly, the detergent concentrate of the DE 100 02 710 A1 has a considerably higher viscosity, resulting in the poor metering ability.

[0115] In the following table 1, there are compared a detergent concentrate according to the invention and the detergent concentrate according to the DE 100 02 710 A1.

TABLE-US-00006 TABLE 1 Comparison of the viscosity of detergent concentrates: Example Composition example 1 of the DE 100 02 710 A1 Viscosity (mPa .Math. s)* 2671 +/ 35 20,000 to 90,000 (suspension) (cream-like paste) *Measurement conditions as in the DE 100 02 710 A: Brookfield Viscometer according to ISO 2555: 1989.

[0116] The individual measurement results for the example 1 are as follows:

TABLE-US-00007 Result example 1 Viscosity, mPa .Math. s Measurement 1 2651 Measurement 2 2711 Measurement 3 2651

[0117] The composition according to example 3 was prepared in addition under different conditions, i.e. at different temperatures. The addition steps d) to h) were carried out such that in the aqueous phase there was not exceeded a temperature of 40 C. (see table 2).

TABLE-US-00008 TABLE 2 Comparison of viscosity - composition according to example 3. Results: Viscosity (mPa .Math. 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.

[0118] In the samples 1, 3 and 4, there was a maximum temperature of 35 C., in sample 2 the temperature increased to 40 C. for a short period of time. The measurement values correlate with the maximum temperature, i.e. in sample 1 the temperatures were the lowest, in sample 2 the highest.