PROCESS FOR MAKING GRANULES AND POWDERS

Abstract

Process for making a modified granule or powder comprising an alkali metal salt of an aminocarboxylate complexing agent (A), said process comprising the steps of

(a) providing a granule or powder comprising an alkali metal salt of an aminocarboxylate complexing agent (A),
(b) treating said granule or powder with the respective aminocarboxylate complexing agent (A) in which at least one amino group or carboxyl group per molecule is present in the acid form, in the presence or absence of water,
(c) performing a heat treatment at a temperature in the range of from 80 to 150 C.

Claims

1. A process for making a modified granule or powder comprising an alkali metal salt of an aminocarboxylate complexing agent (A), said process comprising the steps of (a) providing a granule or powder comprising an alkali metal salt of an aminocarboxylate complexing agent (A), (b) treating said granule or powder with the aminocarboxylate complexing agent (A) in which at least one amino group or carboxyl group per molecule is present in the acid form, in the presence or absence of water, and (c) performing a heat treatment at a temperature in the range of from 80 to 150 C.

2. The process according to claim 1, wherein step (b) is performed by spraying an aqueous solution or slurry of the aminocarboxylate complexing agent (A) in which at least one amino or carboxyl group is present in the acid form on said powder or granule, and wherein step (c) includes an at least partial removal of water by evaporation.

3. The process according to claim 1, wherein steps (b) and (c) are performed in a fluidized bed or in an essentially horizontal cylindrical drying apparatus containing a stirring element that rotates around an essentially horizontal axis.

4. The process according to claim 1, wherein the granule or powder of said aminocarboxylate complexing agent (A) in step (a) is a trialkali metal salt of methylglycine diacetic acid (MGDA).

5. The process according to claim 1, wherein the granule or powder of said aminocarboxylate complexing agent (A) in step (a) is a granule or powder from compounds according to general formula (I)
[CH.sub.3CH(COO)N(CH.sub.2COO).sub.2]M.sub.3-xH.sub.x (I) wherein M is selected from alkali metal cations, same or different, and x in formula (I) is in the range of from zero to 0.30.

6. The process according to claim 4, wherein methylglycine diacetate (MGDA) alkali metal salt (A) is selected from the racemic mixture or mixtures of the enantiomers with predominantly the L-enantiomer with an ee value in the range of from 0.1 to 20%.

7. The process according to claim 1, wherein the aminocarboxylate complexing agent (A) used in step (b) is selected from the free acid, mono- or dialkali metal salts, or combinations thereof.

8. A granule or powder of a solid alkali metal salt (A) of an aminocarboxylate complexing agent wherein said granule or powder has a pH value gradient, the pH value being higher in the core than at the surface.

9. A granule or powder of a solid alkali metal salt (A) of an aminocarboxylate complexing agent wherein (A) in the core is selected from compounds according to general formula (I)
[CH.sub.3CH(COO)N(CH.sub.2COO).sub.2]M.sub.3-xH.sub.x (I) wherein M is selected from alkali metal cations, same or different, and x is in the range of from zero to 0.3 and (A) at the surface is selected from the same compound but with x being in the range of from 1.0 to 3.0.

10. The granule according to claim 8, wherein said granule has an average particle diameter (d50) in the range of from 150 m to 1.5 mm.

11. The powder according to claim 8, wherein said powder has an average particle diameter (d50) in the range of from 50 m to 100 m.

12. The granule or powder according to claim 8, wherein the XRD pattern of said powder or granule exhibits a peak at 2=9.1 and a duplet peak at 214.23 and 14.95, or peaks at 2=698, 13.99 and 17.77, or peaks at 2=14.06 and 18.41 and 26.82, determined with CuK radiation.

13. A method for manufacturing a cleaning agent comprising using a powder or granule according to claim 8.

14. A method for manufacturing an automatic dishwashing detergent comprising using a powder or granule according to claim 8.

15. A cleaning agent comprising at least one powder or granule according to claim 8.

16. The granule according to claim 9, wherein said granule has an average particle diameter (d50) in the range of from 150 m to 1.5 mm.

17. The granule according to claim 9, wherein said granule has an average particle diameter (d50) in the range of from 50 m to 100 m.

18. The granule or powder according to claim 9, wherein the XRD pattern of said powder or granule exhibits a peak at 2=9.1 and a duplet peak at 2 14.23 and 14.95, or peaks at 2=698, 13.99 and 17.77, or peaks at 2=14.06 and 18.41 and 26.82, determined with Cu-Ka radiation.

19. A method for manufacturing a cleaning agent or an automatic dishwashing detergent comprising using a powder or granule according to claim 9.

20. A cleaning agent comprising at least one powder or granule according to claim 9.

Description

[0175] Brief description of the drawing: FIG. 1: XRD pattern of MGDA-H.sub.3 (top), MGDA-NaH.sub.2 (middle) and MGDA-Na.sub.2H. CuK, 2 (1.54 ).

[0176] X-ray diffraction (XRD) data was collected as powder X-ray using a diffractometer (D8 Advance Series II, Bruker AXS GmbH) equipped with a LYNXEYE detector operated with a Copper anode X-ray tube running at 40 KV and 40 mA. The geometry was Bragg-Brentano, and air scattering was reduced using an air scatter shield.

[0177] Data collection: Samples were homogenized in a mortar and then pressed into a standard flat sample holder provided by Bruker AXS GmbH for Bragg-Brentano geometry data collection. The flat surface was achieved using a glass plate to compress and flatten the sample powder. The data was collected from the angular range 2 to 80 2Theta with a step size of 0.02 2Theta while the variable divergence slit was set to a fixed angle of 0.1. The peak position and intensity determination was performed using DIFFRAC.EVA. (User Manual for DIFFRAC.EVA, Bruker AXS GmbH, Karlsruhe.)

[0178] The following tables lists the reflections associated with the given substances. The reflections from the NaCl crystals were neglected.

[0179] General: Percentages refer to percent by weight unless specifically indicated otherwise.

STARTING MATERIALS

[0180] Solution (A.1): 40% by weight aqueous solution of the trisodium salt of methylglycine diacetic acid (MGDA-Na.sub.3).

[0181] Granule (A.1): Experiment 5 of WO 2017/220308 was repeated. A granule of MGDA-Na.sub.3, diameter 350 to 1000 m, average particle diameter (d50) 725 m, determined by sieving, also referred to as C-Gr.3. C-Gr.3 was obtained.

[0182] Complexing agent (B.1): methylglycine diacetic acid (MGDA-H.sub.3) as powder and with a purity of about than 72%, determined by iron binding capacity, remainder: sodium sulfate.

[0183] Complexing agent (B.2): methylglycine diacetic acid (MGDA-H.sub.3) as powder with a purity of about than 85%, determined by iron binding capacity, remainder: sodium chloride.

[0184] Complexing agent (B.3): methylglycine diacetic acid (MGDA-H.sub.3) as powder with a purity of about than 95%, determined by iron binding capacity

[0185] Complexing agent (B.4): methylglycine diacetic acid (MGDA-H.sub.3) as powder with a purity of about than 80%, determined by iron binding capacity, remainder: sodium chloride.

[0186] Complexing agent (B.5): methylglycine diacetic acid (MGDA-HNa.sub.2) as powder with a of about than 84%, determined by iron binding capacity, remainder: NaCl.

[0187] The iron binding capacity was determined by potentiometric FeCl.sub.3 titration.

Manufacture of (B.1)

[0188] A 3-litre vessel made of glass equipped with overhead stirrer and temperature measuring device was charged with 1000 g of solution (A.1) at ambient temperature. Then, 226 g of sulfuric acid (96 wt %) were added slowly under stirring. During addition the temperature was not allowed to rise above 50 C., by adjustment of dosing speed and active cooling via water/NaCl bath.

[0189] After complete H.sub.2SO.sub.4 addition (pH=0,8; determined as 1 wt % solution in water) crystallization could be observed and the resulting suspension was stirred at ambient temperature and normal pressure for 60 to 120 minutes, then filtered over a suction filter and the filter cake washed three times with 100 ml of water (5 C.). The wet filter cake was dried for 12 h at 40 C. to yield 140 g of white crystalline powder (B.1).

Manufacture of (B.2)

[0190] A 3-litre vessel made of glass equipped with overhead stirrer and temperature measuring device was charged with 750 g of solution (A.1) at ambient temperature. Then, 483 g of aqueous hydrochloric acid (30 wt %) were added slowly under stirring. During addition the temperature was not allowed to rise above 50 C., by adjustment of dosing speed and active cooling via water/NaCl bath.

[0191] After complete HCl addition (pH=0,4; determined as 1 wt % solution in water) the resulting solution was transferred in a flask and concentrated at 70 C. and 20 mbar until crystallization could be observed. The resulting suspension was stirred at ambient temperature and normal pressure for 30 to 60 minutes, then filtered over a suction filter and the filter cake washed three times with 100 mL of cold water (5 C.). The wet filter cake was dried for 12 h at 40 C. to yield 162 g of white crystalline powder (B.2).

Manufacture of (B.3)

[0192] A 3-litre vessel made of glass equipped with overhead stirrer and temperature measuring device was charged with 120 g of complexing agent (B.2) and 1000 g of deionized water and stirred at 50 C. until a clear solution was obtained. The resulting solution was transferred in a flask and concentrated at 70 C. and 20 mbar until crystallization could be observed. The resulting suspension was stirred at ambient temperature and normal pressure for 60 to 120 minutes, then filtered over a suction filter and the filter cake washed three times with 50 mL of cold water (5 C.). The wet filter cake was dried for 12 h at 40 C. to yield 42 g of white crystalline powder (B.3).

Manufacture of (B.4)

[0193] 160 g of white crystalline powder (B.4) were obtained following the same method as (B.2) but using 1000 g of solution (A.1) and 337 g of hydrochloric acid (30 wt %). pH value after HCl addition was 2.3 (determined as 1 wt % solution in water).

Manufacture of (B.5)

[0194] 283 g of white crystalline powder (B.5) were obtained following the same method as (B.2) but using 1000 g of solution (A.1) and 193 g of hydrochloric acid (30 wt %). pH value after HCl addition was 8.0 (determined as 1 wt % solution in water).

I. MANUFACTURE OF INVENTIVE GRANULES

I.1 Manufacture of Spray Liquors

I.1.1 Manufacture of Spray Liquor SL. 1

[0195] A vessel was charged with 265 g of demineralized water and 35 g of complexing agent (B.1) was added. Spray liquor SL. 1 was obtained. was stirred vigorously. and then heated to 70 C. for 3 hours and then subjected to spray granulation.

I.1.2 Manufacture of Spray Liquor SL.2

[0196] A vessel was charged with 268 g of demineralized water and 32 g of complexing agent (B.2) was added. The spray liquor SL.2 so obtained was stirred vigorously. and then heated to 70 C. for 3 hours and then subjected to spray granulation.

I.2. Spray Granulation

I.2.1 Manufacture of Inventive Granule Gr. 1

[0197] Step (a.1): A lab scale granulator, commercially available as WFP-Mini from the company DMR, was charged with 300 g of granule (A.1).

[0198] An amount of 22 Nm.sup.3/h of nitrogen with a temperature of 130-160 C. was blown from the bottom. A fluidized bed of (A.1) was obtained.

Step (b.1), Simultaneously with Step (c.1):

[0199] Spray liquor SL.1 was heated to 70 C. for 3 hours under vigorous stirring and then introduced into the spray granulator by spraying 5 to 7 g/minute SL.1 (about 22 C.) into the fluidized bed of (A.1) from step (a.1) from the bottom through a three-fluid nozzle.

[0200] The pressure of the atomizing gas was 1.5 to 2.0 bar, abs. Granule (A.1) was coated, and the bed temperature, which corresponds to the surface temperature of the solids in the fluidized bed, was 95-105 C.

[0201] When SL.1 was used up, the granule obtained was cooled down. inventive granule Gr. 1 was recovered.

I.2.2 Manufacture of Inventive Granule Gr.2

[0202] Step (a.2): A lab scale granulator, commercially available as WFP-Mini from the company DMR, was charged with 300 g of granule (A.1).

[0203] An amount of 22 Nm.sup.3/h of nitrogen with a temperature of 130 to 160 C. was blown from the bottom. A fluidized bed of (A.1) was obtained.

Step (b.2), Simultaneously with Step (c.2):

[0204] Spray liquor SL.2 was heated to 70 C. for 3 hours under vigorous stirring and then introduced into the spray granulator by spraying 5 to 7 g/minute SL.2 (about 22 C.) into the fluidized bed of

[0205] (A.1) from step (a.2) from the bottom through a three-fluid nozzle.

[0206] The pressure of the atomizing gas was 1.5 to 2.0 bar, abs. Granule (A.1) was coated, and the bed temperature, which corresponds to the surface temperature of the solids in the fluidized bed, was 95 to 105 C.

[0207] When SL.2 was used up, the granule obtained was cooled down. Granule Gr.2 were recovered as inventive granules.

[0208] In the above examples, nitrogen can be replaced by air having the same temperature.

I.2.3 Manufacture of a Comparative Granule C-Gr.4

[0209] Example 1 of U.S. Pat. No. 8,940,678 was followed. C-Gr.4 was obtained.

[0210] II. TESTING OF INVENTIVE GRANULES AND OF COMPARATIVE GRANULE

[0211] Test protocol: 10 g of inventive granule or of C-Gr.3 were mixed with 5 g Na-percarbonate and placed in a vial having a permeable stopper to allow an exchange with the surrounding atmosphere. The vial was stored for 28 days in a climate-chamber at 35 C. and 70% humidity.

[0212] The discoloration of the above stored mixtures was determined by measuring the b-value of the CIELAB color space (Mach 5 measurement).

TABLE-US-00002 TABLE 2 Yellowing behavior of inventive granules and of comparative granule C-Gr.3 b-value (start) b-value (14 days) b-value (28 days) Gr.1 2.1 7.9 21.7 Gr.2 2.7 10.7 23.9 C-Gr.3 3.1 13.1 27.8

[0213] The XRD patterns of Gr.1 and Gr.2 exhibited a peak at 2=14.06 and 18.41 and 26.82, determined with CuK radiation (1.54 ). The XRDs spectrum of C-Gr.3 exhibited neither peak at 2=9.1 and a duplet peak at 214.23 and 14.95, nor peaks at 2 of 6.98, 13.99 and 17.77, nor peaks at 2 of 14.06 and 18.41 and 26.82.

TABLE-US-00003 TABLE 3 XRD data (all) MGDANa.sub.2H MGDANaH.sub.2 MGDAH.sub.3 rel. rel. rel. Intensity Intensity Intensity Angle d Value [%] Angle d Value [%] Angle d Value [%] 9.10 9.71 100 9.10 9.71 100 11.81 7.49 56 10.64 8.31 12 10.64 8.31 12 14.06 6.29 93 13.26 6.67 20 13.26 6.67 20 14.99 5.91 35 14.23 6.22 46 14.23 6.22 46 18.41 4.81 72 14.95 5.92 43 14.95 5.92 43 20.20 4.39 100 15.76 5.62 10 15.76 5.62 10 20.26 4.38 66 16.76 5.28 15 16.76 5.28 15 20.84 4.26 21 16.92 5.24 29 16.92 5.24 29 22.14 4.01 30 19.30 4.60 20 19.30 4.60 20 22.62 3.93 90 19.80 4.48 7 19.80 4.48 7 22.92 3.88 83 20.99 4.23 20 20.99 4.23 20 24.22 3.67 22 21.20 4.19 43 21.20 4.19 43 24.52 3.63 46 21.38 4.15 69 21.38 4.15 69 24.70 3.60 33 22.92 3.88 86 22.92 3.88 86

TABLE-US-00004 TABLE 4 characteristic XRD data (selection) MGDANa.sub.2H MGDANaH.sub.2 MGDAH.sub.3 Angle d Value Angle d Value Angle d Value 9.10 9.71 6.98 12.65 14.06 6.29 14.23 6.22 13.99 6.32 18.41 4.81 14.95 5.92 17.77 4.99 26.82 3.32

[0214] Table 5: Water uptake during storage due to hygroscopicity

[0215] The hygroscopicity was determined by storing at 25 C. and 50% relative humidity over a period of 48 hours. In the alternative, so-called tropic conditions are storing at 35 C. and 70 to 90% relative humidity over a period of 24 hours. Flowability grades: from zero (free flowable granule/powder) to 4 (granule/powder has dissolved). The grades and the water content (Karl-Fischer titration) were determined.

TABLE-US-00005 Humidity [% by weight] Flowability After 1 After 8 after 24 after 48 grade hour hours hours hours after 48 h Gr.1 4.0 11.6 13.3 14.7 2.5 Gr.2 5.1 13.1 15.6 17.1 2.3 C-Gr.3 3.2 12.5 18.7 22.3 n.d. C-Gr.4 5.7 27.7 54.2 68.7 4.0 n.d.: not determined