Process for making a granule

Abstract

Process for making a powder or granule containing (A) at least one chelating agent selected from alkali metal salts of methyl glycine diacetic acid (MGDA) and of iminodisuccinic acid (IDS), (B) at least one compound of general formula (I a) or (I b) ##STR00001## wherein A.sup.1 is selected from (CH.sub.2).sub.a wherein the variable a is in the range of from 4 to 20, e is selected from zero and 1, and R.sup.1 being the same or different and selected from OC.sub.1-C.sub.10-alkyl and C.sub.1-C.sub.10-alkyl, and, optionally, (C) at least one homo- or copolymer of (meth)acrylic acid, partially or fully neutralized with alkali, said process comprising the steps of (a) providing an aqueous solution or slurry containing chelating agent (A) and said compound (B) and, if applicable, (co)polymer (C), with a pH value in the range of from 10 to 12, (b) removing most of said water by spray drying or spray granulation.

Claims

1. A process for making a powder or granule comprising (A) at least one chelating agent selected from alkali metal salts of methyl glycine diacetic acid (MGDA) and of iminodisuccinic acid (IDS), and (B) at least one compound of general formula (I a) or (I b) ##STR00011## wherein A.sup.1 is selected from (CH.sub.2).sub.a wherein the variable a is in the range of from 4 to 20, and e is selected from zero and 1, R.sup.1 being the same or different and selected from C.sub.1-C.sub.10-alkyl and O-C.sub.1-C.sub.10-alkyl, and, optionally, (C) at least one homo-or copolymer of (meth) acrylic acid, partially or fully neutralized with alkali, said process comprising the steps of (a) providing an aqueous solution or slurry containing chelating agent (A) and said compound (B) and, if applicable, (co) polymer (C), and (b) removing most of said water by spray drying or granulation.

2. The process according to claim 1, wherein in step (b), a gas with an inlet temperature of more than 125 C. is used.

3. The process according to claim 1, wherein, in the solution of step (a), the molar amount of alkali is lower than the molar amount of carboxyl groups of chelating agent (A) and-if applicable-(co) polymer (C).

4. The process according to claim 1, wherein the amount of compound (B) is in the range of from 50 to 2,500 ppm by weight, referring to chelating agent (A).

5. The process according to claim 1, wherein the weight ratio of chelating agent (A) and (co) polymer (C) is in the range of from 100:1 to 4:1.

6. The process according to claim 1, wherein step (b) is performed with a two-fluid nozzle.

7. The process according to claim 1, wherein step (b) is followed by a step (c) including separating off fines.

8. The process according to claim 1, wherein the pH value of the aqueous solution or slurry provided in step (a) is the range of from 9 to 12.

9. A powder or granule comprising (A) at least one chelating agent selected from alkali metal salts of methyl glycine diacetic acid (MGDA) and iminodisuccinic acid (IDS), and (B) at least one compound of general formula (I a) or (I b) ##STR00012## wherein A.sup.1 is selected from (CH.sub.2).sub.a wherein the variable a is in the range of from 4 to 20, e is selected from zero and 1, and R.sup.1 being the same or different and selected from C.sub.1-C.sub.10-alkyl and O-C.sub.1-C.sub.10-alkyl, and, optionally, (C) at least one homo-or copolymer of (meth) acrylic acid, partially or fully neutralized with alkali, wherein said powder or granule contains at least 75% by weight of chelating agent (A).

10. The powder or granule according to claim 9 having a residual moisture content in the range of from 1 to 20% by weight.

11. The granule according to claim 9 having an average diameter in the range of from 0.1 mm to 2 mm.

12. The powder or granule according to claim 9, wherein chelating agent (A) is a combination of the disodium salt of MGDA and the trisodium salt of MGDA.

13. The powder or granule according to claim 9, wherein the amount of compound (B) is in the range of from 50 to 2,500 ppm by weight, referring to chelating agent (A).

14. A method for the manufacture of a cleaning agent for fibers or hard surfaces comprising combining a granule or powder according to claim 9 and at least one bleaching agent, wherein said cleaning agent comprises at least one peroxy compound.

15. A cleaning agent containing comprising at least one peroxy compound and at least one powder or granule according to claim 9.

16. The method according to claim 14, wherein said at least one peroxy compound is selected from percarbonates, persulfates and/or perborates.

Description

(1) The present invention is further illustrated by working examples.

GENERAL REMARKS

(2) Nl: Norm liter, liters under normal conditions; Nm.sup.3: norm cubic meter, cubic meter under normal conditions

(3) Starting Materials:

(4) (A.1): [CH.sub.3CH(COO)N(CH.sub.2COO).sub.2]Na.sub.3-xH.sub.x with x=0.1

(5) (A.2): [CH.sub.3CH(COO)N(CH.sub.2COO).sub.2]Na.sub.3 with x=zero

(6) (B.1): compound (para-I a)

(7) (C.1): polyacrylic acid, 25 mol-% neutralized with sodium hydroxide, M.sub.w: 4,000 g/mol, determined by GPC and referring to the free acid

(8) The molecular weight of polymers (C.1) and (C.2) was determined GPC. Said measurements were performed at a pH value of 7.4 (phosphate buffer), stationary phase: cross-linked polyacrylate, mobile phase: water, pH value 7.4, phosphate buffer with 0.01 M NaN.sub.3.

(9) I. Manufacture of Spray Liquors and Spray Granulation

(10) I.1 Manufacture of Spray Liquor SL.1

(11) A vessel was charged with 3 kg of a 40% by weight aqueous solution of (A.1) and 1.5 g of (B.1) (load of 1,250 ppm based on (A.1). The spray liquor SL.1 so obtained was stirred and subjected to spray granulation.

(12) I.2 Spray Granulation of Spray Liquor SL.1

(13) A lab scale granulator, commercially available as WFP-Mini from the company DMR, was charged with 200 g of solid MGDA-Na.sub.3 spherical particles, diameter 350 to 1000 m, and 100 g of milled MGDA-Na.sub.3 particles. An amount of 25 Nm.sup.3/h of nitrogen with a temperature of 150 to 180 C. was blown from the bottom. A fluidized bed of MGDA-Na.sub.3 particles was obtained. The above liquor SL.1 was introduced by spraying 13 g/minute SL.1 (nozzle gas: about 22 C.) into the fluidized from the bottom through a three-fluid nozzle (absolute atomizing pressure in the nozzle: 2.5 bar, absolute purging gas: 3 bar). Granules were formed, and the bed temperature, which corresponds to the surface temperature of the solids in the fluidized bed, was 95 to 110 C.

(14) Every 15 to 20 minutes, an aliquot of granule (150 to 250 g) was removed from the granulator and classified by sieving. Three fractions were obtained: coarse particles (diameter>1 mm), value fraction (diameter>350 m and <1 mm) and fines (diameter<350 m). The coarse particles (diameter>1 mm), were milled down using a hammer mill (Kinetatica Polymix PX-MFL 90D) at 4000 rpm (rounds per minute), 2 mm mesh. The powder so obtained and the fines were returned into the fluidized bed in the granulator. The value fraction, which was not milled down, was collected.

(15) After 2 kg of sprayed liquid, a steady state was reached. Then, the value fraction was collected as inventive granules, Gr.1.

(16) In the above example, nitrogen can be replaced by air having the same temperature.

(17) Examples I.3: Manufacture of Further Inventive Granules and Comparative Granules

(18) The above protocol was repeated but modifications according to Table 1 were made. The pH value of SL.2 was in the range of from 9 to 12.

(19) TABLE-US-00001 TABLE 1 modifications (A) Amount of (B.1) Temperature of spray liquor Granule SL.2 (A.1) 2,375 ppm 22 C. Gr.2 SL.3 (A.2) 2,250 ppm 70 C. Gr.3 SL.4 (A.2) 1,250 ppm 70 C. Gr.4 SL.5 (A.1) 1,250 ppm 70 C. Gr.5 C-SL.6 (A.2) none 22 C. C-Gr.6
II. Yellowing Tests of Inventive Granule

(20) 10 g of respective granule Gr.1 were mixed with 5 g sodium percarbonate. The mixture so obtained was placed in a Falcon tube, which was closed with a membrane lid. The mixture was stored at 35 C. and 78% relative humidity. For homogenization, the mixture was shaken for 2 minutes after 7, 12, 14, 19, 21 and 26 days for 2 minutes each. After 26 days, the change of colour (from white to yellow represented as Ab) was measured with a spectrophotometer (Elrepho).

(21) The results are summarized in Table 2. As comparative granule C-Gr.6, a granule from (A.2) without any compound (B), was manufactured and tested as above.

(22) TABLE-US-00002 TABLE 2 results of peroxide test, b values immediately 26 days b color change C-Gr.6 4.5 27.4 22.9 Gr.1 0.6 16.3 15.7
III. Example Detergent Compositions

(23) From inventive granules, example detergent compositions for automatic dishwashing detergents can be formulated by mixing the respective components according to Table 3.

(24) TABLE-US-00003 TABLE 3 Example detergent compositions for automatic dishwashing All amounts in g/sample ADW.1 ADW.2 ADW.3 Gr.1 30 22.5 15 Protease 2.5 2.5 2.5 Amylase 1 1 1 n-C.sub.18H.sub.37O(CH.sub.2CH.sub.2O).sub.9H 5 5 5 Sodium percarbonate 10.5 10.5 10.5 TAED 4 4 4 Na.sub.2CO.sub.3 19.5 19.5 19.5 Sodium citrate dihydrate 15 22.5 30 HEDP 0.5 0.5 0.5 ethoxylated polyethylenimine, 20 option- option- option- EO/NH group, M.sub.n: 30,000 g/mol ally: 0.1 ally: 0.1 ally: 0.1

(25) The inventive detergent compositions result in excellent automatic dishwashing results.