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US-20260125623-A1 - PROCESS FOR MAKING A GRANULE OR POWDER CONTAINING A COMPLEXING AGENT

US20260125623A1US 20260125623 A1US20260125623 A1US 20260125623A1US-20260125623-A1

Abstract

Process for making a granule comprising an alkali metal salt of an aminocarboxylate complexing agent (A), said process comprising the steps of (a) providing an aqueous slurry or solution comprising an alkali metal salt of an aminocarboxylate complexing agent (A), (b) treating said slurry or solution with carbon dioxide, (c) removing most of the water by evaporation.

Inventors

  • Astrid Schmidt
  • Mattias ARNDT
  • Michael Klemens Mueller
  • Nataliia SHYMANSKA
  • Matthias VOGES

Assignees

  • BASF SE

Dates

Publication Date
20260507
Application Date
20220817
Priority Date
20210825

Claims (17)

  1. 1 . A process for making a granule comprising an alkali metal salt of an aminocarboxylate complexing agent (A), said process comprising the steps of (a) providing an aqueous slurry or solution comprising an alkali metal salt of an aminocarboxylate complexing agent (A), (b) treating said slurry or solution with carbon dioxide, and (c) removing most of the water by evaporation.
  2. 2 . The process according to claim 1 , wherein step (b) is performed by passing a stream of CO 2 through said solution or slurry.
  3. 3 . The process according to claim 1 , wherein step (c) is performed in a fluidized bed or in a spouted bed or in an essentially horizontal cylindrical drying apparatus comprising a stirring element that rotates around an essentially horizontal axis.
  4. 4 . The process according to claim 1 , wherein step (b) is performed at a temperature in the range of from 10 to 90° C.
  5. 5 . The process according to claim 1 , wherein step (b) is performed at a pressure in the range of from ambient pressure up to 10 bar.
  6. 6 . 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) wherein M is selected from alkali metal cations, same or different, and x is in the range of from zero to 0.30.
  7. 7 . 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).
  8. 8 . The process according to claim 1 , wherein the pH value of the solution or slurry at the end of step (b) is in the range of from 9 to 11.
  9. 9 . A granule or powder of an alkali metal salt (A) of an aminocarboxylate complexing agent wherein said granule or powder contains in the range of from 0.1 to 10% by weight alkali metal carbonate.
  10. 10 . The granule or powder according to claim 9 , wherein the alkali metal salt (A) of an aminocarboxylate complexing agent is selected from compounds according to general formula (I a) wherein M is selected from alkali metal cations, same or different, and x1 is in the range of from zero to 1.2.
  11. 11 . The granule according to claim 9 , wherein said granule has an average particle diameter d50 in the range of from 150 μm to 1.5 mm.
  12. 12 . The powder according to claim 9 , wherein said granule has an average particle diameter d50 in the range of from 30 μm to 125 μm.
  13. 13 . The granule or powder according to claim 9 , wherein the alkali metal carbonate is uniformly dispersed within the particles of the granule or powder.
  14. 14 . A method for the manufacture of a cleaning agent comprising mixing a powder or granule according to claim 9 with at least one non-ionic surfactant.
  15. 15 . A solid automatic dishwashing composition comprising a granule according to claim 9 .
  16. 16 . The method of claim 14 , further comprising mixing one or more enzymes.
  17. 17 . The solid automatic dishwashing composition of claim 15 , further comprising one or more enzymes.

Description

The present invention is directed towards a process for making a granule comprising an alkali metal salt of an aminocarboxylate complexing agent (A), said process comprising the steps of (a) providing an aqueous slurry or solution comprising an alkali metal salt of an aminocarboxylate complexing agent (A),(b) treating said slurry or solution with carbon dioxide,(c) removing most of the water by evaporation. Furthermore, the present invention is directed towards granules and powders of alkali metal salts of aminocarboxylate. Chelating agents of the aminocarboxylate type such as methyl glycine diacetic acid (MGDA) and glutamic acid diacetic acid (GLDA) and their respective alkali metal salts are useful seques-trants for alkaline earth metal ions such as Ca2+ and Mg2+. A lot of aminocarboxylates show good biodegradability and are thus environmentally friendly. For that reason, they are recom-mended and used for various purposes such as laundry detergents and for automatic dishwashing (ADW) formulations, in particular for so-called phosphate-free laundry detergents and phos-phate-free ADW formulations. Depending on the type of product—liquid home care and fabric care products versus solid home care and fabric care products—and the manufacturing process of solid home care and fabric care products care product manufacturers may either prefer to handle solutions of aminocarboxylates or solid aminocarboxylates, for example joint spray drying or solid mixing. Powders and granules of aminocarboxylates may be shipped economically due to their high active ingredient content that goes along with low water content. Therefore, convenient processes for providing granules are still of great commercial interest. In WO 2009/103822, a process is disclosed in which slurries are granulated that have a certain solids content, with a gas inlet temperature of 120° C. or less. In WO 2012/168739, a process is disclosed wherein slurries of complexing agents are spray-dried under non-agglomerating conditions. Both processes have their shortcomings. A low gas inlet temperature requires highly concentrated slurries or a huge amount of gas per unit of granule. A process using non-agglomerating conditions provides for powders only. Many processes for making granules lead to undesired lumps, also referred to as overs. Such lumps may be milled down and re-introduced into the spray drying process, see WO 2017/220308, leading to good granules. However, the need to mill down a considerable share of lumps makes the process economically less favourable. It was therefore an objective of the present invention to provide a process that allows to produce granules or powders of aminocarboxylate complexing agents with a low tendency of lump formation during the water removal. Additionally, it was an objective of the present invention to provide a process for making granules or powders of aminocarboxylate complexing agents with a low tendency to yellow and a good storage stability. Accordingly, the process as defined at the outset has been defined, hereinafter also referred to as inventive process or as process according to the present invention. The inventive process comprises three mandatory steps, step (a), step (b), and step (c). They may in brief also be referred to as (a), (b) or (c), respectively. Steps (a), (b), and (c) are performed subsequently. Steps (a) to (c) are described in more detail below. In step (a), an aqueous solution or slurry of an aminocarboxylate complexing agent (A) is provided, hereinafter also referred to as “salt (A)”. In this context, alkali metal salts are selected from lithium salts, sodium salts, potassium salts, rubidium salts, and cesium salts and combinations of at least two of the foregoing, with potassium salts being preferred and sodium salts being more preferred. Examples of aminocarboxylate complexing agents are ethylenediamine tetraacetate (EDTA), iminodisuccinates, and diacetates of amino acids, especially alanine, glutamic acid, and aspar-tic acid, as well as combinations of at least two of the aforementioned. Preferably, salt (A) is selected from methylglycine diacetic acid (MGDA). Salts (A) may refer to fully neutralized aminocarboxylate complexing agents (A) and to partially neutralized aminocarboxylate complexing agents (A). In one embodiment of the present invention, salt (A) is selected from compounds according to general formula (I) whereinM is selected from alkali metal cations, same or different, preferably K or Na or combinations thereof, and even more preferably Na, andx is in the range of from zero to 1.0, preferably zero to 0.30. In any way, aqueous solutions or slurries of salt (A) may bear a cation other than alkali metal. It is thus possible that minor amounts, such as 0.01 to 5 mol-% of total MGDA, respectively, bear alkali earth metal cations such as Mg2+ or Ca2+, or an Fe2+ or Fe3+ cation. As mentioned above, in step (a) an aqueous solution or slurry of salt (A) is provided. Aqueous solutio