CN1219197A - Spray Dried Components Containing Chelating Agents - Google Patents

Abstract

The present invention relates to a spray-dried component in the form of free-flowing particles with high chelating agent activity, comprising: i) at least 50%, preferably at least 60% (by weight) chelating agent; ii) 1%–25%, preferably 5%–10% (by weight) alkali metal or alkaline earth metal sulfate; and iii) preferably less than 10% (by weight) free water.

Description

Spray Dried Components Containing Chelating Agents

The present invention relates to spray-dried components comprising a chelating agent, in particular diethylenetriaminepenta(methylenephosphonic acid) or a salt thereof. This component is suitable for use in granular detergent products and also as an intermediate in the manufacture of soap bars, detergent tablets and other forms of detergent such as extrudates, agglomerates and the like.

US-A-4259200, issued March 31, 1981, discloses phosphonates chelated with calcium, magnesium, zinc or aluminum ions in a molar ratio of metal ion to phosphonate of at least 1:1. It states that the magnesium and phosphonate may be premixed in any suitable solvent, including water, optionally mixed with other detergent ingredients and spray dried. Improved storage stability was found in bleaching compositions.

EP-A-225309, published June 10, 1987, discloses the addition of alkali metal or alkaline earth metal salts to granules comprising diethylenetriaminepenta(methylenephosphonic acid) to achieve improved flow and storage properties the goal of. Based on the dry weight of the chelating agent, the amount of the sulfate is 60%-200%, which is equivalent to the weight ratio of the metal ion salt to the chelating agent being 0.6:1-2:1. After spray drying, the preferred water content is less than 10% by weight of the granules.

The prior art does not suggest that it is possible to prepare spray-dried components with high levels of chelating agent (at least 50% by weight) and still retain good flow properties.

It is an object of the present invention to provide spray-dried components in the form of flowable granules with high chelator activity.

Invention Summary

The object of the present invention is achieved by a spray-dried component comprising: i) at least 50%, preferably at least 60% (by weight) of a chelating agent; ii) 1%-25%, preferably 5%-10% ( weight) alkali metal or alkaline earth metal sulphate; and iii) preferably less than 10% by weight free water.

The chelating agent is preferably phosphonic acid or succinic acid, or a phosphonate or succinate, more preferably the chelating agent is selected from diethylenetriaminepenta(methylenephosphonic acid), ethylenediamine-N,N'-di Succinic acid or a mixture thereof, or a salt thereof.

The alkaline earth metal is preferably magnesium.

Detailed description of the invention

The spray-dried components of the present invention comprise a chelating agent. Chelating agents are used, for example, in detergent compositions due to their ability to chelate metal ions such as iron and/or manganese to form soluble chelates. Suitable chelating agents may be selected from amino carboxylates, amino phosphonates, polyfunctionally substituted aromatic chelating agents and mixtures thereof.

Useful aminocarboxylates include ethylenediaminetetraacetate ("EDTA"), N-hydroxyethylethylenediaminetriacetate, nitrilotriacetate, ethylenediaminetetrapropionate, triethylene Ethyltetraaminehexaacetate, diethylenetriaminepentaacetate and ethanol diglycine, their alkali metal, ammonium and substituted ammonium salts and mixtures thereof.

Useful amino phosphonates include ethylenediaminetetrakis (methylene phosphonate), sold as DEQUESTR. These amino phosphonates preferably do not contain alkyl or alkenyl groups having more than about 6 carbon atoms.

Particularly preferred chelating agents are diethylenetriaminepenta(methylenephosphonic acid) ("DTPMP") and ethylenediaminetetrakis(methylenephosphonic acid) (EDTMP).

Polyfunctionally substituted aromatic chelating agents are also suitable for use in the compositions of the present invention. See US Patent No. 3,812,044, Connor et al., issued May 21, 1974. Preferred compounds of this type in acid form are dihydroxydisulfobenzenes, such as 1,2-dihydroxy-3,5-disulfobenzene.

A preferred biodegradable chelating agent for use in the present invention is ethylenediamine-N,N'-disuccinate ("EDDS"), especially as issued in the U.S. patent of Hartman and Perkins on November 3, 1987. Its [S,S] isomer described in patent US-A-4704233.

Magnesium sulfate, aluminum or zinc are preferred for use in the present invention, with magnesium sulfate being most preferred. Epsom salt, MgSO ₄ .7H ₂ O, the hydrated, crystalline form of magnesium sulfate with 7 moles of water, is particularly preferred.

Chelating agents for use in the present invention are conveniently provided from commercially available aqueous sources. Typical commercially available solutions have from about 40% to about 60% by weight chelator activity. The spray-dried components can be prepared by mixing this aqueous solution with the required amount of sulfate, adding more water if necessary to reduce the total solids content, and then by spraying the solution into a conventional counter-current or co-current spray drying Particles form in the tower. In the tower, the water is evaporated by the hot gas, usually by hot air, preferably to a level of free water in the finished spray-dried component of less than 10% by weight.

Optionally the spray-dried components can also be further passed through drying and/or cooling steps in conventional process equipment such as fluidized beds. The oversize and fine particle fractions are usually removed, for example by passing the particles through a vibrating screen.

Additional processing steps, including additional granulation steps with other ingredients, agglomeration or compaction, and dry blending, can produce finished products such as detergent powders, soap bars and tablets.

Example

Example 1 Example 2 DTPMP 80 84MgSO ₄ .7H ₂ O 10 5 Sodium chloride 5 6 Free water 5 5DTPMP is diethylene triamine penta(methylene phosphonic acid) heptasodium salt MgSO ₄ .7H ₂ O is Epsom Salt

All amounts are % by weight unless otherwise stated.

The spray-dried components produced in these examples had a bulk density of 500 g/l to 700 g/l. The component absorbs very little moisture (e.g. from atmospheric humidity) after preparation, thus reducing or eliminating flow and caking problems even in environments of high temperature and humidity.

Claims (6)

1. spray-dried component, it comprises:

ⅰ) sequestrant;

ⅱ) 1%-25% (weight) basic metal or alkaline earth metal sulphate; With

ⅲ) free-water,

It is characterized in that this spray-dried component comprises at least 50% (weight) sequestrant.

2. according to the spray-dried component of claim 1, it comprises:

ⅰ) at least 60% (weight) sequestrant;

ⅱ) 5%-10% (weight) basic metal or alkaline earth metal sulphate; With

ⅲ) be lower than 10% (weight) free-water.

3. according to the spray-dried component of claim 1 or 2, wherein sequestrant is phosphonic acids or succsinic acid, or phosphonate or succinate, or its mixture.

4. according to the spray-dried component of claim 3, wherein sequestrant is selected from diethylenetriamine five (methylene phosphonic acid), quadrol-N, N '-disuccinic acid, diethylenetriamine five (methylene phosphonic acid) salt, quadrol-N, N '-disuccinate or its mixture.

5. according to the spray-dried component of any aforementioned claim, wherein alkaline-earth metal is a magnesium.

6. according to the spray-dried component of claim 5, wherein alkaline earth metal sulphate is the crystalline hydrate form, MgSO ₄.7H ₂O.