STAIN REMOVAL THROUGH NOVEL OXIDIZER AND CHELANT COMBINATION

Abstract

The present invention relates to a detergent composition comprising alkali metal carbonate, a chelant selected from the group consisting of MGDA, alkali metal tripolyphosphate, GLDA, and mixtures thereof, alkali metal percarbonate, and a peroxidation catalyst, wherein the molar ratio of chelant to alkali metal percarbonate is in the range of 1.8 to 3.4. The detergent composition is particularly suited for the removal of tea and coffee stains.

Claims

1-13. (canceled)

14. A method of using a detergent composition comprising: providing a warewashing detergent composition comprising: alkali metal carbonate as a chelant methylglycinediacetic acid and optionally glutamic acid diacetic acid and/or alkali metal tripolyphosphate, alkali metal percarbonate, and a peroxidation catalyst according to the formula ##STR00010## wherein: L.sub.1 and L.sub.2 can either be separate ligands or can combine to be a single molecule, each L independently is an organic ligand containing at least three nitrogen atoms that coordinate with the metal M; M is Mn or Fe; each X independently is a coordinating or bridging group selected from the group consisting of H.sub.2O, OH.sup.−, SH.sup.−, HO.sub.2.sup.−, O.sup.2−, O.sub.2.sup.2−, S.sup.2−, F.sup.−, Cl.sup.−, Br.sup.−, I.sup.−, NO.sub.3.sup.−, NO.sub.2.sup.−, SO.sub.4.sup.2−, SO.sub.3.sup.2−, PO.sub.4.sup.3−, N.sub.3.sup.−, CN.sup.−, NR.sub.3, NCS.sup.−, RCN, RS.sup.−, RCO.sub.2.sup.−, RO.sup.−, and ##STR00011##  with R being hydrogen or a C.sub.1 to C.sub.6 alkyl group; Y is a counter ion; wherein the molar ratio of chelant to alkali metal percarbonate is in the range of 1.8 to 3.4; wherein said molar ratio is calculated based on the total molar amount of methylglycinediacetic acid, glutamic acid N,N-diacetic acid, and alkali metal tripolyphosphate; wherein for the purpose of calculating said molar ratio alkali metal percarbonate is assumed to have the formula 2(M.sub.2CO.sub.3).Math.3H.sub.2O.sub.2, where M represents an alkali metal; and wherein the total amount of methylglycine diacetic acid, glutamic acid N,N-diacetic acid and alkali metal tripolyphosphate is not more than 35% by weight; and removing tea and coffee soil.

15. The method according to claim 14, wherein the detergent composition is diluted to provide a use solution with a concentration of 0.1 to 10.

16. The method according to claim 14, wherein the detergent composition is used at a temperature of 20 to 85° C.

17. The method according to claim 14, wherein the detergent composition comprises as a chelant MGDA, GLDA, and an alkali metal tripolyphosphate.

18. The method according to claim 17, wherein the detergent composition comprises at most 28% by weight alkali metal tripolyphosphate.

19. The method according to claim 14, wherein the detergent composition comprises 5 to 30% by weight alkali metal percarbonate.

20. The method according to claim 14, wherein the detergent composition provides a pH of at least 8 when diluted in distilled water at a concentration of 1 g/l.

21. The method according to claim 14, wherein L is a ligand according to formulae (II) to (IV) ##STR00012## wherein each R.sup.1 is independently selected from the group consisting of hydrogen and C.sub.1-C.sub.6 alkyl.

22. The method according to claim 14, wherein Y is selected from the group consisting of Cl.sup.−, Br.sup.−, I.sup.−, NO.sub.3.sup.−, ClO.sub.4.sup.−, NCS.sup.−, BPh.sub.4.sup.−, BF.sub.4.sup.−, PF.sub.6.sup.−, R.sup.2—SO.sub.3.sup.−, R.sup.2—SO.sub.4.sup.−, and R.sup.2—CO.sub.2.sup.−, wherein R.sup.2 is hydrogen or a C.sub.1 to C.sub.4 alkyl group.

23. The method according to claim 14, wherein the detergent composition comprises 0.0005 to 0.12% by weight of the metal M in the form of a peroxidation catalyst complex.

24. The method according to claim 14, wherein the detergent composition further comprises at least one additional compound comprising surfactants, activating agents, additional chelating/sequestering agents, silicates, detergent fillers or binding agents, defoaming agents, anti-redeposition agents, enzymes, dyes, odorants, or mixtures thereof.

25. The method according to claim 14, wherein the detergent composition further comprises 1.5 to 5% by weight nonionic surfactant.

26. The method according to claim 14, wherein the detergent composition further comprises 0.1 to 5% by weight additional chelating/sequestering agents.

Description

EXAMPLES

[0104] The following example illustrates the invention by testing the removal of tea soil from ceramic tiles.

[0105] Ceramic tiles (5.1×15.2 cm white, glazed ceramic tiles) were stained with tea soil (Lipton brand tea) according to the following procedure. Hard water having a hardness of >249.9 mg/l CaCO.sub.3 was heated to >71° C. The tea was then mixed into the hot hard water. The ceramic tiles were then immersed into the tea for 1 min and then taken out for 1 min to dry. This procedure was repeated until a stain was formed, which was typically after 25 cycles. The tiles were then cured for 48 hrs at room temperature. At this time the tiles are ready for testing.

[0106] Cleaning test were carried out in a standard automatic dishwasher. The cleaning efficiency was evaluated by visually comparing the amount of soil left on the tiles after one full cleaning cycle to the amount of soil on the tiles before the cleaning procedure. The percentage of stain removal was quantified by image analysis of scanned test tiles. The results were rated according to table 1:

TABLE-US-00001 TABLE 1 Rating % of stain removal 5 100 4 80-99.9 3 20-79.9 2 <20 1 no removal

[0107] A rating of 5 was considered to be an excellent result. A rating of 4 (at least 80% stain removal) was considered to be an acceptable cleaning performance.

[0108] Cleaning performance tests were carried out by charging the washing tank with the detergent compositions at the desired use concentration. Unless otherwise noted, all amounts in the following are given in % by weight or ppm by weight, respectively.

[0109] In a first experiment, the effect of adding a mixture of sodium percarbonate and the peroxidation catalyst bis(N,N′,N″-trimethyl-1,4,7-triazacyclononane)-trioxo-dimanganese (IV) di(hexafluorophosphate)monohydrate (Dragon PF6) to a mixture of soda ash, Trilon M (trisodium salt of methylglycinediacetic acid), STPP, and GLDA was tested. The results are shown in table 2.

TABLE-US-00002 TABLE 2 Tea stain rating at use concentration 1000 1200 1400 Formula ppm ppm ppm 44% Ash, 8% Trilon M, 1 2 5 22% STPP, 4% GLDA 44% Ash, 8% Trilon M, 1 4 5 22% STPP, 4% GLDA, 15% sodium percarbonate, 0.025% Dragon PF6

[0110] This first experiment shows that a better tea stain removal performance can be achieved when sodium percarbonate and catalyst are combined with chelants compared to a formula containing chelants only.

[0111] In a second experiment, the effect of adding 150 ppm sodium percarbonate and 0.025 ppm Dragon PF6 to varying concentrations of Trilon M was tested in the presence of 800 ppm by weight sodium carbonate and 40 ppm by weight nonionic surfactant (polyoxypropylene-polyoxethylene block copolymer, Pluronic 25R2). The results are shown in table 3.

TABLE-US-00003 TABLE 3 % of stain removal Trilon M Trilon M With Percarbonate and level (ppm) only Dragon PF6  0 N/A −11.6 350 −5.3 18.9 375 −6.3 53.2 400 2.1 48.1 425 85.4 N/A

[0112] This second experiment shows that for satisfactory stain removal, a use concentration of 425 ppm Trilon M is required. In contrast, by adding 150 ppm sodium percarbonate and 0.025 ppm Dragon PF6, good stain removal can already be achieved at a Trilon M concentration of as low as 375 ppm.

[0113] In a third experiment, the effect of different concentrations of sodium percarbonate, Dragon PF6, and Trilon M was tested in the presence of 800 ppm sodium percarbonate. The results are shown in table 4.

TABLE-US-00004 TABLE 4 Trilon M Percarbonate Dragon PF6 Tea stain (ppm) (ppm) (ppm) rating 350 — — 2 375 — — 3 400 — — 4 425 — — 5 50 200 0.05 2.5 50 400 0.1 4 50 500 0.125 5 50 600 0.15 5 350 100 0.025 3.5 350 200 0.05 4

[0114] The third experiment showed that a concentration of at least 400 ppm Trilon M or at least 400 ppm sodium percarbonate is required for an acceptable stain removal (rating 4 or higher). However, a good result can also be achieved when combining 350 ppm Trilon M with 200 ppm sodium percarbonate (corresponding to a molar ratio of chelant to percarbonate of 1.015). This demonstrates a synergistic effect between the chelant and percarbonate.