Use of modified polyaspartic acids in dishwashing detergents

Abstract

The present invention relates to the use of modified polyaspartic acids in dishwashing detergents, in particular as dispersants, film inhibitors and spot inhibitors. The invention also relates to dishwashing detergent compositions comprising modified polyaspartic acids.

Claims

1. An additive in dishwashing detergents which comprises a modified polyaspartic acid is preparable by polycondensation of (i) 50 to 99 mol % of aspartic acid and methanesulfonic acid in a ratio of 200:1 to 5:1; and (ii) 1 to 50 mol % of at least one carboxyl-containing compound, and subsequent hydrolysis of the cocondensates with the addition of a base, where (ii) is not aspartic acid.

2. The additive according to claim 1, where (i) is 50 to 95 mol % of aspartic acid and (ii) is 5 to 50 mol % of at least one carboxyl-containing compound.

3. The additive according to claim 1, where (i) is 80 to 95 mol % of aspartic acid and (ii) is 5 to 20 mol % of at least one carboxyl-containing compound.

4. The additive according to claim 1, where (ii) is a monocarboxylic acid, a polycarboxylic acid, a hydroxycarboxylic acid and/or an amino acid.

5. The additive according to claim 1, where (ii) is selected from the group consisting of 1,2,3,4-butanetetracarboxylic acid, citric acid, glycine and glutamic acid.

6. The additive according to claim 1, where the base is alkali metal base, alkaline earth metal bases; carbonates; ammonia; primary, secondary or tertiary amines; or bases with primary, secondary or tertiary amino groups.

7. The additive according to claim 1 in dishwashing detergents for machine dishwashers.

8. The additive according to claim 1, where the modified polyaspartic acid is preparable by polycondensation of (i) 60 to 95 mol % of aspartic acid and methanesulfonic acid in a ratio of 100:1 to 10:1, and (ii) 5 to 40 mol % of at least one carboxyl-containing compound, and subsequent hydrolysis of the cocondensates with the addition of a base, where (ii) is not an aspartic acid.

9. The additive according to claim 1, where the modified polyaspartic acid is preparable by polycondensation of (i) 80 to 95 mol %, of aspartic acid and methanesulfonic acid in a ratio of 50:1 to 12:1; and (ii) 5 to 20 mol %, of at least one carboxyl-containing compound, and subsequent hydrolysis of the cocondensates with the addition of a base, where (ii) is not an aspartic acid.

10. A dishwashing detergent composition comprising (a) 1-20% by weight of at least one modified polyaspartic acid preparable by polycondensation of (i) 50 to 99 mol % of aspartic acid and methanesulfonic acid in a ratio of 200:1 to 5:1; and (ii) 1 to 50 mol % of at least one carboxyl-containing compound, and subsequent hydrolysis of the cocondensates with the addition of a base, where (ii) is not aspartic acid; (b) 0-50% by weight of complexing agent; (c) 0.1-80% by weight of builders and/or cobuilders; (d) 0.1-20% by weight of nonionic surfactants; (e) 0-30% by weight of bleaches and bleach activators; (f) 0-8% by weight of enzymes; and (g) 0-50% by weight of additives.

11. The dishwashing detergent composition according to claim 10, where the composition is suitable for machine dishwashers.

12. The dishwashing detergent composition according to claim 10, comprising (a) 2-12% by weight of at least one modified polyaspartic acid; (b) 3-50% by weight of methylglycinediacetic acid and salts thereof; (c) 15-65% by weight of builders and/or cobuilders (d) 0.5-10% by weight of nonionic surfactants (e) 0-30% by weight of bleaches and bleach activators (f) 0-8% by weight of enzymes; and 0-50% by weight of additives.

13. The additive according to claim 1, where the modified polyaspartic acid is preparable by polycondensation of (i) 80 to 95 mol %, of aspartic acid and methanesulfonic acid in a ratio of 200:1 to 5:1; and (ii) 5 to 20 mol %, of at least one carboxyl-containing compound, and subsequent hydrolysis of the cocondensates with the addition of a base, where (ii) is not an aspartic acid.

Description

EXAMPLE 1

(1) Preparation of the Modified Polyaspartic Acids

(2) Molar ratios are given in each case.

(3) Polymers According to the Invention Polymer 1: polycondensate of L-aspartic acid/BTC 1.0:0.1 Polymer 1b: polycondensate of L-aspartic acid/BTC 1.0:0.1 in the presence of 5 mol % (based on L-Asp) of methanesulfonic acid Polymer 2: polycondensate of L-aspartic acid/BTC 1.0:0.2 Polymer 3: polycondensate of L-aspartic acid/citric acid 1.0:0.5 Polymer 4: polycondensate of L-aspartic acid/glycine 1.0:0.1 Polymer 5: polycondensate of L-aspartic acid/glutaminic acid 1.0:0.1 Polymer 5b: polycondensate of L-aspartic acid/glutaminic acid 1.0:0.1 in the presence of 5 mol % (based on L-Asp) of methanesulfonic acid

(4) BTC=1,2,3,4 butanetetracarboxylic acid

(5) Comparison Polymers Polymer C1: polyaspartic acid Na salt, Mw 3000 g/mol Polymer C2: polyaspartic acid, Na salt, Mw 5400 g/mol

(6) Polymers According to the Invention

(7) Polymer 1:

(8) A 2 l capacity reactor with stirrer was charged with 133.10 g of L-aspartic acid, 70 g of water and 23.42 g of 1,2,3,4-butanetetracarboxylic acid. The reaction mixture was heated with stirring for 4 h at a temperature of 210° C. while simultaneously distilling off water. The resulting melt of the modified polyaspartamide was cooled and then comminuted. In order to prepare the aqueous sodium salt solution of the modified polyaspartic acid, 100 g of the comminuted reaction mass was dispersed into 100 g of water, the mixture was heated to 70° C. and, at this temperature, enough of a 50% strength aqueous sodium hydroxide solution was added for the pH to be in the range of 7-8. During this, the powder dispersed in water gradually dissolved, giving a clear aqueous sodium salt solution of the modified polyaspartic acid. The weight-average molecular weight (Mw) of the modified polyaspartic acid was 2600 g/mol.

(9) Polymer 1b:

(10) The synthesis and work-up of this polymer took place precisely as described in polymer 1, but additionally charging 4.81 g of methanesulfonic acid to the reactor. The weight-average molecular weight (Mw) of the modified polyaspartic acid was 3300 g/mol.

(11) Polymer 2:

(12) Analogously to the preparation of polymer 1, 133.10 g of L-aspartic acid and 46.83 g of 1,2,3,4-butanetetracarboxylic acid were charged to the reactor and polycondensed for 2.5 h at 240° C. The resulting melt of the modified polyaspartamide was cooled, comminuted and hydrolyzed as described in example 1 to give an aqueous sodium salt solution of the modified polyaspartic acid. The weight-average molecular weight (Mw) of the modified polyaspartic acid was 1870 g/mol.

(13) Polymer 3:

(14) Analogously to the preparation of polymer 1, 133.10 g of L-aspartic acid and 96.07 g of citric acid were charged to the reactor and polycondensed for 5 h at 180° C. The resulting melt of the modified polyaspartamide was cooled and then comminuted. In order to prepare the aqueous sodium salt solution of the modified polyaspartic acid, 100 g of the cooled and comminuted reaction mass were dissolved in 100 g of water and, with ice cooling, enough of a 50% strength aqueous sodium hydroxide solution was added for the pH to be in the range 7-8. The weight-average molecular weight (Mw) of the modified polyaspartic acid was 1320 g/mol.

(15) Polymer 4:

(16) Analogously to the preparation of polymer 1, 133.10 g of L-aspartic acid, 30.00 g of water and 7.51 g of glycine were charged to the reactor and polycondensed for 7 h at 220° C. The resulting melt of the modified polyaspartamide was cooled, comminuted and hydrolyzed as described in example 1 to give an aqueous sodium salt solution of the modified polyaspartic acid. The weight-average molecular weight (Mw) of the modified polyaspartic acid was 6060 g/mol.

(17) Polymer 5:

(18) Analogously to example 1, 133.10 g of L-aspartic acid, 30.00 g of water and 14.71 g of L-glutaminic acid were charged to the reactor and polycondensed for 7.5 h at 220° C. The resulting melt of the modified polyaspartamide was cooled, comminuted and hydrolyzed as described in example 1 to give an aqueous sodium salt solution of the modified polyaspartic acid. The weight-average molecular weight (Mw) of the modified polyaspartic acid was 3810 g/mol.

(19) Polymer 5b:

(20) The synthesis and work-up of this polymer took place precisely as described in polymer 5, but additionally charging 4.81 g of methanesulfonic acid to the reactor. The weight-average molecular weight (Mw) of the modified polyaspartic acid was 6100 g/mol.

(21) Comparison Polymers

(22) Polymer C1 (Polyaspartic Acid M):

(23) In a round-bottomed flask, 10 g of maleamide (prepared by the reaction of maleic anhydride with ammonia) were polycondensed for 2 h at 240° C. The reaction mass swelled up like a foam during this and could be readily comminuted after cooling. The comminuted polyaspartamide was hydrolyzed as described in example 1 to give an aqueous polyaspartic acid sodium salt solution. The weight-average molecular weight (Mw) was 3000 g/mol.

(24) Polymer C2 (Polyaspartic Acid T):

(25) In a rotary evaporator, 133.10 g of L-aspartic acid were polycondensed for 2 h at a temperature of 220-240° C. The resulting polyaspartamide was hydrolyzed as described in example 1 to give an aqueous polyaspartic acid sodium salt solution. The weight-average molecular weight (Mw) was 5400 g/mol.

EXAMPLE 2

(26) Determination of the Molecular Weight (Mw)

(27) The weight-average molecular weight (Mw) of the examples was determined with the help of GPC (gel permeation chromatography) under the following conditions:

(28) TABLE-US-00001 Column Suprema 100 10μ (Polymer Standard Service) Eluent 0.08 mol/l TRIS buffer pH = 7.0 in dest. water + 0.15 mol/l NaCl + 0.01 mol/l NaN.sub.3 Column temperature 35° C. Flow rate 0.8 mL/min Injection 100 μL Concentration 1.5 mg/mL Detector DR1 Agilent 1100UV GAT-LCD 503 (260 nm)

(29) Sample solutions were filtered over Sartorius Minisart RC 25 (0.2 μm). Calibration was carried out with narrowly distributed Na-PAA standards from Polymer Standard Service with molecular weights of M=1250 to M=193 800. Additionally, Na acrylate with a molecular weight of M=96 and a PEG standard with M=620, which equates with Na-PAA M=150 was. The values outside of this elution range were extrapolated. The evaluation limit was approx. M=298 g/mol.

EXAMPLE 3

(30) Dishwasher Tests

(31) The polymers were tested in the following phosphate-free test formulation PF1. The composition of the test formulation PF1 is given in table 1 (data in % by weight).

(32) TABLE-US-00002 TABLE 1 test formulation PF1 Constituent PF 1 Protease 2.5 Amylase 1.0 Nonionic surfactant 5 Polymer 10 Sodium percarbonate 10.2 Tetraacetylethylenediamine 4 Sodium disilicate 2 Sodium carbonate 19.5 Sodium citrate dihydrate 35 Methylglycinediacetic acid, 10 Na salt Hydroxyethane-(1,1- 0.8 diphosphonic acid)

(33) Data in % by weight, based on the total amount of all components

(34) Here, the following experimental conditions were observed: Dishwasher: Miele G 1222 SCL Program: 65° C. (with prerinse) Wear: 3 knives (Karina nickel chrome knives, Solex Germany GmbH, Eisingen/Germany) 3 Amsterdam 0.2 L drinking glasses 3 “OCEAN BLUE” BREAKFAST PLATES (MELAMINE) 3 porcelain plates: RIMMED PLATE FLAT 19 CM Arrangement: Knives in the cutlery tray, glasses in the upper basket, plates arranged in the lower basket Dishwashing detergent: 18 g Addition of soiling: 50 g of ballast soiling is dosed, in thawed form, with the formulation after the prerinse; see below for composition Clear rinse temperature: 65° C. Water hardness: 21° German hardness (Ca/Mg): HCO3 (3:1): 1.35 Rinse cycles:—15; in each case 1 h break in between (10 min closed door, 50 min opened door) Evaluation: Visually after 15 wash cycles

(35) The evaluation of the wear was carried out after 15 cycles in a darkened chamber under light behind an aperture plate using a grading scale from 10 (very good) to 1 (very poor). Grades from 1 to 10 were awarded both for spotting (very many, intensive spots=1, no spots=10), as well as for the film (1=very considerable film, 10=no film)

(36) Composition of the Ballast Soiling:

(37) Starch: 0.5% potato starch, 2.5% gravy Grease: 10.2% margarine Protein: 5.1% egg yolk, 5.1% milk Others: 2.5% tomato ketchup, 2.5% mustard, 0.1% benzoic acid, 71.5% water
Result:

(38) The formulations with modified polyaspartic acid according to the invention are characterized in particular by their very high film-inhibiting effect towards inorganic and organic deposits on glass and knives. Furthermore, they increased the cleaning power of the dishwashing detergent and favored the run-off of the water from the wear, meaning that particularly clear glasses and shining metal cutlery items were obtained.

(39) Table 2 below lists the grades for filming (F) and spotting (S) on knives and drinking glasses.

(40) TABLE-US-00003 TABLE 2 test results test formulation 1 (PF 1) Polymer Knives (F + S) Glasses (F + S) Without polymer 7.0 7.0 Polymer 1 15.3 11.7 Polymer 1b 15.7 12.0 Polymer 2 14.6 11.7 Polymer 3 12.7 10.0 Polymer 4 14.0 10.3 Polymer 5 13.7 10.3 Polymer 5b 114.3 11.1 Polymer C1 8.3 7.7 Polymer C2 11.4 9.0