GB2203163A

GB2203163A - Dishwasher detergents

Info

Publication number: GB2203163A
Application number: GB08807751A
Authority: GB
Inventors: Jean-Pierre Chavannes
Original assignee: Sandoz AG
Current assignee: Sandoz AG
Priority date: 1987-04-03
Filing date: 1988-03-31
Publication date: 1988-10-12
Anticipated expiration: 2008-03-31
Also published as: IT8847796A0; FR2613378A1; GB8807751D0; CH675881A5; GB2203163B; JPS63273700A; IT1219894B

Description

A IMFMEMENTS IN CR RELATIM TO CM.AMC COMPOOMS 150-5161 4 i,: ' p, Lu. C-,;

-- - 1y ' This invention relates to stable liquid bleach-containing detergent =positions which can be used as a single detergent in mechanical dishyashers.

The invention provides a stable aqueous liquid detergent canposition containing:

_Y a) 0.5 - 7% by weight of a polyacrylic acid,, a polyhydroxyacrylic acid or a mixture thereof (calculated as free acid) b) 0.4 - 6% by weight of a chlorine-resistant phosphonate or organi. c phosphate, and c) 3 - 15% by weight sodium hypochlorite,, whereby the pH of the camposition is adjusted to pH 13 or above with sodium and/or potassium hydroxide and/or potassium metasilicate,, and the weight ratio of sodium ions to potassium ions in the canposition is not greater than 1:1.

The detergent canposition may further contain:

d) 0-12% of a sodium or potassium polyphosphate e) 0-1.5% of a sodium or potassium tolylsulphonate f) 0-10% potassium carbonate,, and g) 0-1.5% of a ch.lorine-resistant,, low foaming surfactant.

150-5161 All of the above percentages given in this specification are by weight unless stated otherwise.

In order to set the pH value to 13 or above, an addition of between 10% and 22% of sodium and/or potassium hydroxide and/or potassium metasilicate is generally required. The total solids content of the aqueous solution is then between 20 and 60%.

The preferred quantities of the various components are, independently, component a) component b) Component c) component d) component e) canponent f) component g) 1-4 % 1-3 % 4-8 % 4-9 % 0.5-1.5 % 1-6 % 0.2-1 % sodium and/or potassium hydroxide and/or potassium metasilicate 12-18%. The total solids content is preferably 25-40 %.

The polymeric acids of component a) include hamopolymers of acrylic acid, methacrylic acid and c(-hydroxyacrylic acid. as well as copolymers of these monamers with each other. The preferred materials are commercially available hamopolymers of acrylic acid and of c(-hydroxyacrylic acid having a molecular weight (as measured by gel permeation chromatography) between 500 and 1,000,000, preferably 1000-500.000. more preferably 2500150.000. Particularly preferred are polyacrylic acids having a molecular weight either in the range 3000-6000 or in the range 80.000-120.000. These polyacrylic acids are preferably used in the form of their aqueous solutions, and are neutralised by the caustic alkali present in the composition, so that they are present in the detergent in salt form.

The phosphonate or phosphate of component b) is present as a sequestering agent. It must be chlorine-resistant; that is, when it is present in the hypochlorite-containing detergent composition, the i 150-5161 available chlorine content of the canposition. as measured by titration. must not decrease significantly with time during storage at ambient temperature. In other words, the available chlorine must not be taken up by reaction with canponent b). The same definition applies to the chlorine-resistant surfactant g).

Preferred camponents b) are of formula I. II or III below:

0 < N+ CH OPOH)3 2 11 0 I CH 3 1 (H0)2p - C - P(OW2 11 1 11 0 OH 0 ii CHCOOH (H0)2 C COOH M "I' CH2 - CH 2 COOH Aminotris(methylenephosphoric acid) (I) is available under the trade name SEQUION OA fram BOZZEM S.p.A.,, Bergamo; Campound III, 2-phosphonabutan-1, 2,4,-tricarboxylic acid, is available under the trade name BAYHIBIT AM fram Bayer AG, Leverkusen.

The sodium hypochlorite of campanent c) is preferably added in the form of a 30% aqueous solution,, for example as normal camercial bleach containing 14% available chlorine.

The sodium or potassium polyphosphate of canponent d) is preferably one of the polyphosphates cammonly used-in detergents, for example sodiumtripolyphosphate.

150-5161 The chlorine-resistant low foaming surfactant of component g) is for example an amine oxide surfactant or,, preferably,, a fully carboxymethylated polyglycol ether. A suitable product of the latter type is commercially available under the trade name SANDOPAN D-PC from Sandoz Ltd.,, Basle, Switzerland.

When sodium polyphosphate or sodium tolylsulphonate are used, or when sodium hydroxide is used to neutralize component a) or to adjust the pH of the composition, care must be taken that the weight ratio of sodium to potassium ions remains no greater than 1:1. In this way the solubility of the various components is assured, and crystallization of the solution is avoided.

Preferably, when no metasilicate or polyphosphate are present.' the Na:K ratio is fran 1:2 to 1:3; when metasilicate is present but polyphosphate is not,, the Na:K ratio is frcm 1:3 to 1:20; when metasilicate is absent but polyphosphate is present. the Na:K ratio is from 1:1.5 to 1:2; and when both metasilicate and polyphosphate are present, the Na:K ratio is from 1:1 to 1:2.

The detergent composition according to the invention may be used as sole detergent in mechanical dishwashers at all normal washing temperatures,, i.e. 20-1000C. The quantity to be used will depend upon how dirty are the dishes to be washed, but normally 1-5 g detergent camposition-per litre of wash water may be added. The selected ranges of the components ensure that the composition has excellent stability both in the concentrated state and upon dilution. The detergent has extremely good cleaning effect upon stubborn dirt for example proteins, fats and oils. It is suitable for use in all types of dishwashing equipment and may be used in both domestic and industrial machines. It is biodegradable,, low-foaming and unaffected by hard water.

The preparation of the detergent composition is preferably carried out by stirring the components into an aqueous solution of metasilicate or sodium or potassiwn hydroxide, in the same order of 150-5161 addition as listed in the Examples. Finally demineralized water is added to obtain the desired concentration, and the mixture is stirred until it is hamogenous.

The following Examples in which all parts and percentages are by weight and temperatures are in degrees Centigrade. illustrate the invention.

Examples 1-10:

Canponents 1. 2. 3.

4.

5.

6.

7.

Potassium metasilicate-(40 % aqueous solution) potassium hydroxide (50 % aqueous solution) polyacrylic acid (M 100,000) semi-neutralised (Na salt) as 29 % aqueous solution (canponent a) polyacrylic acid (MW 4500) as 49 % aqueous solution (camponent a) ccmpcund of formula I (SEQUION OA) as 43 % aqueous solution (canponent b) compound of formula III (BAYHIBIT AM) as 50 % aqueous solution (canponent b) canpoand of formula II (1hydroxyethan-l,,1-diphosphonic acid) as 60 % aqueous solution (canponent b) sodium tolylsulphonate (33 % aqueous solution) (canponent e) potassium tolylsulphonate (40 % aqueous solution) (camponent e) sodium tripolyphosphate (canponent d) 8. 9. 10. 11. sodium hypochlorite (30 % aqueous solution) (camponent c) 12. sodium hydroxide (30 % aqueous solution) 13. potassium carbonate (camponent f) 14. Sandapan D-PC (25 % aqueous solution) (canponent g).

The camponents are mixed together in the quantities shown in the following Table I, and in the order in which they are listed. In all cases a mobile. pale yellow solution is obtained which is stable fran 0- 500 and has excellent washing power at 200 as well as at the boil. Excellent results are obtained in large-scale dishwashing equipment (restaurant), 1 > 1 ---1 to ---4 "I A C> tn r-I Table I

Component's Examples: 1 2 3 4 5 6 7 8 9 10 1. 40 38,0 30,0 - 20,0 - 45,0 32,0 - 39,0 2. 5 5,0 5,5 27,5 17,0 30,0 5,0 1510 30,0 5,0 3. 6 510 10,0 - - 6,0 5,0 - 5,0 4. - - - 6,0 6,0 6,0 - - 6,0 - 5. 4 3,0 - - - - 4,0 4,0 - 310 6. - - 4,0 4,0 4,0 4,0 - - - - - - 3,0 Total Y, 8. 2 2,0 - 9. - - 3,0 10. - 7,0 7,0 7,0 7,0 - - - 11. 25 19,0 19,0 18,0 15,0 19,0 20,0 22,0 12. - - 810 3,5 9,0 - - - 13. 3 - - - 3,0 3,0 14. - - 1,0 7,0 7,0 1910 20,0 demi n. is 23,0 16,5 34,0 22,,0 41,0 15,0 15,0 35,0 21,0 water 100% 100,0% 100,0% 100.0% 100,0% 100,0% 100,0% 100,0% 100'n',100,0% 150-5161 The corresponding percentages of canponents a-g in Examples 1-10 are shown in Table II.

t.' r.

Table II

Example 1 2 3 4 5 6 7 8 9 10 Component a 1.74 1.45 2.9 3.0 3.0 3.0 1.74 1.45 3.0 1.45 b 1.72 1.29 2.0 2.0 2.0 2.0 1.72 1.72 1.8 1.29 c 7.5 5.7 5.7 5.4 4.5 5.7 6.0 6.6 5.7 6.0 d - 7.0 7.0 7.0 7.0 - - 7.0 7.0 e 0.66 0.66 1.2 f 3.0 3.0 3.0 co 0.25 - - alkali 18.5 11.7 17.15 14.8 19.2 15.0 20.5 20.3 15.0 18.1 total solids 33.1 33.1 34.8 32.2 35.7 25.7 33.6 34.5 32.5 33.8 Y/ 1,1 150-5161

Claims

CLAIMS: -

1. A stable aqueous liquid detergent camposition containing:

0.5 - 7% by weight of a polyacrylic acid,, a polyhydroxyacrylic acid or a mixture thereof (calculated as free acid) b) 0.4 - 6% by weight of a chlorine-resistant phosphonate or organic phosphate, and 3 - 15% by weight sodium hypochlorite, c) whereby the pH of the =position is adjusted to pH 13 or above with sodium and/or potassium hydroxide and/or potassium metasilicate, and the weight ratio of sodium ions to potassium ions in the camposition is not greater than 1:1.

2. A =position according to Claim 1 containing 10-22% of sodium and/or potassium hydroxide and/or potassium metasilicate and with a total solids content of 20-60%.

3. A camposition according to Claim 1 containing at least one of the following capponents:

d) up to 12% of a sodium or potassium polyphosphate e) up to 1.5% of a sodium or potassium tolylsulphonate f) up to 10% potassium carbonate, and g) up to 1.5% of a chlorine-resistant, low foaming surfactant.

4. A camposition according to Claim 3 containing 1-4% of camponent a) 1-3% of ccimponent b) 4-8% of camponent c) 12-18% sodium and/or potassium hydroxide and/or potassium metasilicate and at least one of the following ccmponents:

- 10 150-5161 4-9% canponent d) 0.5-1.5% ccmpondnt e) 1-6% canponent f) 0.2-1% canponent g).

5. A canposition according to any one of the preceding claims in which canponent a) is a hanapolymer of acrylic or hydroxyacrylic acid of molecular weight 1000-500,000.

6. A canposition according to Claim 5 in which ccmponent a) is polyacrylic acid of MW 3000-6000 or 80,000-120,000.

7. A canposition according to any one of the preceding claims in which canponent b) is selected frcm aminotris(methylenephosphoric acid),, 1hydroxyethan-l,,1-diphoric acid and 2-phosphonabutan-1,2,4-tricarboxylic acid.

8. A canposition according to any one of Claims 3-7 in which canponent d) is sodiun tripolyphosphate.

9. A =position according to any one of Claims 3-8 in which canponent g) is an amine oxide or fully carbogymethylated polyglycol ether surfactant.

10. A canposition according to any one of the preceding claims in which no metasilicate or polyphosphate is present,, and the Na:K ratio is fran 1:2 to 1:3 by weight.

11. A canposition according to any one of Claims 1-9 in which metasilicate is present. polyphosphate is absent and the Na:K ratio is fran 1:3 to 1:20 by weight.

12. A canposition according to any of Claims 1-9 in which metasilicate is absent. polyphosphate is present and the Na:K ratio is fran 1:1.5 to 1:2 by weight.

1,11 11 150-5161

13. A canposition according to any one of Claims 1-9 in which both metasilicate and polyphosphate are present and the Na:K ratio is f ran 1:1 to 1:2 by weight.

14. A stable aqeucus liquid detergent canposition as described in any one of Examples 1-10.

15. A process for the washing of dishes in a mechanical dishwasher camprising the addition of 1-5 g/1 of a canposition according to any one of the preceding claims.

Published 1988 at The Patent Office, State House, 6W71 High Holborn, London WC1R 4TP. Further copies may be obtained from The Patent office, Sales Branch, St Mary Cray. Orpington, Kent BR5 3RD. Printed by Multiplex techniques ltd, St Mary Cray. Kent. Con. 1187.