Process for preparing a solid composition comprising at least one aminocarboxylate complexing agent

Description

The present invention deals with a process for preparing a solid, preferably storage stable, composition comprising at least one aminocarboxylate complexing agent, comprising the follow- ing steps: a) Providing an initial aminocarboxylate composition with a content of 0.1 and 50 % by weight, preferably 1 to 25 % by weight, solid particles of aminocarboxylates of orthorhom- bic crystal system, relative to the total initial solid composition, b) Increasing the relative humidity (rH) to at least 50% and/or adding at least 1 % by weight of water or of an aqueous solution (SO) or slurry (SL) with a water content of at least 10 % by weight, preferably at least 30% by weight, relative to the total weight of the aqueous solution or slurry, c) keeping the obtained composition at a temperature of 20 to 95 °C over a period of 1 mi- nute to 5 months, d) optionally drying the resulting solid composition, preferably to a residual moisture content of less than 20 %, preferably resulting in a solid aminocarboxylate composition with an in- creased content of orthorhombic crystal form.

Complexing agents such as methyl glycine diacetic acid (MGDA) and glutamic acid diacetic acid (GLDA) and their respective alkali metal salts are useful sequestrants for alkaline earth metal ions such as Ca ²⁺ and Mg ²⁺ . For that reason, they are recommended and used for various pur- poses such as laundry detergents and for automatic dishwashing (ADW) formulations, in partic- ular for so-called phosphate-free laundry detergents and phosphate-free ADW formulations. For shipping such complexing agents, in most cases either solids such as granules are being ap- plied or aqueous solutions.

Solid compositions, e. g. granules and powders, have the advantage of being essentially water- free. That means that in case of shipping, no water has to be shipped, and costs for extra weight can be avoided. (The term “solid” has its usual meaning, i. e. refers to the state of a compound or composition at room temperature, i. e. at 20 °C).

Methods for providing granules or powders of chelating agents, also in combination with other compounds like polymers, have been described in the art, for example in WO 2015/121170 A1 . Furthermore, EP 0 845 456 A2 describes a process for preparing a crystalline solid consisting essentially of certain glycine-N,N-diacetic acid derivatives by adjusting the water content of the initial mass containing glycine-N,N-diacetic acid derivatives to a range of 10 to 30 % by weight and subsequently inducing crystallisation. In the examples, MGDA powder and MGDA solution are mixed and heated, then a crystalline solid resulted. However, there is no mention of a de- gree of crystallinity, and in particular no indication of the content of crystals of orthorhombic crystal form. It is purported that the solid resulting from the examples was storage stable; how- ever, there is no (verifiable) experimental evidence for this allegation.

However, solid compositions containing aminocarboxylate complexing agents frequently en- counter problems when stored for an extended period of time.

For example, many powders and granules show the problem of yellowing (discoloration), in par- ticular when contacted with chlorine-free bleaching agents, such as, but not limited to inorganic peroxides, which are, together with complexing agents like MGDA, frequently used in detergent formulations, for example dishwashing detergent formulations, e.g. ADW formulations. Exam- ples of inorganic peroxides are sodium perborate, sodium persulfate and in particular sodium percarbonate.

A lot of additives have been tried in order to limit such yellowing. Most of them, however, either deteriorate the activity of the bleaching agent or considerably slow down the dissolution of the complexing agent, both effects being undesirable.

One way known in the art to improve the storage stability e. g. of MGDA is an increase of the degree of crystallinity of the complexing agent, as well as an increase of amount of MGDA in orthorhombic crystal form. There are some solidification processes which deliver MGDA with a relatively high content of orthorhombic crystal form, e. g., EP2 257 522 B1 ; however, these pro- cesses, e.g. evaporative crystallization or drying process starting from a slurry, mostly are not economically interesting or do not deliver sufficiently pure orthorhombic product.

Thus, it was an objective of the present invention to avoid the problems mentioned above. In particular, it was an objective of the present invention to provide storage stable solid composi- tions containing aminocarboxylate complexing agents. It was also an objective to provide solid compositions containing aminocarboxylate complexing agents which show a reduced tendency for yellowing when contacted with chlorine-free bleaching agents, such as, but not limited to inorganic peroxides. Furthermore, it was an objective of the present invention to provide solid compositions contain- ing aminocarboxylate complexing agents with an increased content of complexing agent, in par- ticular MGDA, in orthorhombic crystal form.

It was also an objective to provide a process for preparing storage stable solid compositions containing aminocarboxylate complexing agents. It was another objective of the present inven- tion to provide a process for preparing solid compositions containing aminocarboxylate com- plexing agents which show a reduced tendency for yellowing when contacted with chlorine-free bleaching agents. Besides, it was an objective of the present invention to provide a process for preparing solid compositions containing aminocarboxylate complexing agents with an increased content of complexing agent, in particular MGDA, in orthorhombic crystal form.

Surprisingly, it was found that the process defined in the appended claims (and in the present description) can overcome the disadvantages and problems mentioned above.

In particular, it was found that the inventive process - involving a step of increasing the relative humidity and/or adding water - leads to solid compositions which show improved yellowing and storage stability.

Furthermore, it was found that the inventive process can help to achieve increased contents of aminocarboxylate complexing agents, e. g. MGDA, in orthorhombic crystal form.

The inventive process for preparing a solid, preferably storage stable, composition comprising at least one aminocarboxylate complexing agent, comprises the following steps: a) Providing an initial aminocarboxylate composition with a content of 0.1 and 50 % by weight, preferably 1 to 25 % by weight, solid particles of aminocarboxylates of orthorhom- bic crystal system, relative to the total initial solid composition, b) Increasing the relative humidity (rH) to at least 50% and/or adding at least 1 % by weight of water or of an aqueous solution (SO) or slurry (SL) with a water content of at least 10 % by weight, preferably at least 30% by weight, relative to the total weight of the aqueous solution or slurry, c) keeping the obtained composition at a temperature of 20 to 95 °C over a period of 1 mi- nute to 5 months, preferably 2 minutes to 1 month, optionally, d) drying the resulting solid composition, preferably to a residual moisture content of less than 20 %, preferably resulting in a solid aminocarboxylate composition with an increased content of orthorhombic crystal form. A further object of the present invention is a solid, preferably storage stable composition com- prising at least one aminocarboxylate complexing agent, obtainable or obtained by the process according to the inventive process.

Another object of the present invention is the use of a solid, preferably storage stable composi- tion comprising at least one aminocarboxylate complexing agent, obtainable or obtained by the inventive process, for manufacturing a detergent or cleaning formulation, preferably a dishwash- ing detergent formulation, more preferably an automatic dishwashing detergent formulation.

In one embodiment of the inventive process, water is added by setting the relative humidity to a range of 50 to 90%, preferably 60 to 85%, and/or by adding at least 1% by weight, preferably 2 to 10 % by weight, of water or of an aqueous solution (SO) or slurry (SL), optionally by spraying the water or aqueous solution (SO) or slurry (SL) onto the initial solid composition.

In a further embodiment of the inventive process, the solid composition is kept at a temperature of 30 to 95 °C over a period of 30 minutes to 1 month, preferably at 30 to 70°C over a period of 30 minutes to 2 weeks, preferably 30 minutes to 48 h.

In the inventive process, the drying may be done at a temperature in the range from 40° to 240°C, preferably 60° to 150°C, more preferably 60° to 120 °C, and/or until a residual moisture content of less than 18 % by weight, relative to the total weight of the solid composition, is reached.

In a further embodiment of the inventive process, the initial composition is prepared by addition of 0.1 and 50 % by weight of orthorhombic aminocarboxylate to a composition without ortho- rhombic aminocarboxylate, or by drying of a slurry or solution of an aminocarboxylate composi- tion containing 0.1 and 70 % by weight of solids content. The drying may be done, for example, by spray drying or spray granulation.

The solids content may be determined by Karl-Fischer titration (with regard to water content), Fe-titration (with regard to content of chelating agent, e. g. MGDA) and calculation of the re- maining content (with regard to content of optional polymer).

The discoloration - which is a yellowing in this case - of the stored mixtures was determined by measuring the b-value of the CIELAB color space (Mach5 measurement device).

In the inventive process, providing solid particles (step a) ) and addition of water (step b) ) may be done simultaneously or consecutively. In an embodiment of the inventive process, the solid particles (step a) ) are in the form of a powder, granule, crystal, compactate, flake, or agglomerate.

The inventive process may at least partially be performed in a mixer, belt dryer, kneader, fluid- ized bed dryer, paddle dryer and/or cone dryer.

The aminocarboxylate complexing agent may be selected from methylglycinediacetic acid (MGDA), (N,N)-Dicarboxymethyl glutamic acid (GLDA), nitrilotriacetic acid (NTA), ethylendia- mine tetraacetic acid (EDTA), ethylenediamine disuccinic acid (EDDS), and their respective alkali salts, preferably sodium salts, more preferably sodium salt of MGDA.

The initial solid composition may further comprise up to 40 % by weight, preferably up to 30% by weight, of at least one organic or inorganic compound or mixtures thereof, relative to the total weight of the initial solid composition.

In an embodiment of the inventive process, the aqueous solution (SO) or slurry (SL) further comprises up to 40 % by weight, preferably up to 30% by weight, of at least one organic or inor- ganic compound or mixtures thereof, relative to the total weight of the aqueous solution (SO) or slurry (SL).

The initial solid composition and/or the aqueous solution (SO) or slurry (SL) may also comprise at least one compound selected from the list consisting of polymers, preferably sulfonated pol- ymers, anti-oxidants, surfactants, colorants, pigments, further complexing agents, organic and inorganic acids and their salts.

The initial solid composition may contain at least one polymer, e. g. homo-polymer and/or co- polymer. The polymer may be selected from homo- and co-polymers of (meth)acrylic acid.

The initial solid composition may contain at least one anti-oxidant.

The initial solid composition may contain at least one surfactant which may be selected from non-ionic, zwitterionic, cationic, and anionic surfactants.

The initial solid composition may contain at least one colorant.

The initial solid composition may contain at least one pigment.

The initial solid composition may contain one or more complexing agents other than MGDA or GLDA, for example IDS, citrate, EDDS and/or phosphonic acid derivatives.

The initial solid composition may contain at least one organic acid (or its salt) with a molecular weight of less than 500 g/mol, e. g. formic acid, acetic acid and/or citric acid.

Within the context of the present invention, the term “storage stable” solid composition refers to a solid composition (comprising at least one aminocarboxylate complexing agent) in combina- tion with a bleaching agent (e.g. percarbonate) which shows an improved or no yellowing upon storage at elevated temperature (e.g. 35°C) and humidity (e.g. 75% r.H.). The yellowing is de- termined by a change in b-value (CIELAB color space, Mach5 measurement device).

Inventive solid compositions, e. g. powders and granules, exhibit overall advantageous proper- ties including but not limited to an excellent yellowing behavior, especially in the presence of bleaching agents. They are therefore excellently suitable for the manufacture of cleaning agents that contain at least one bleaching agent, such cleaning agent hereinafter also being referred to as bleach. In particular inventive solid compositions are suitable for the manufacture cleaning agent for fibers or hard surfaces wherein said cleaning agent contains at least one peroxy com- pound.

Inventive solid compositions (e. g. powders or granules) may easily be converted into compac- tates and into agglomerates.

Another aspect of the present invention is therefore the use of a solid composition for the manu- facture of a cleaning agent that contains at least one bleaching agent, and in particular for the manufacture of cleaning agent for fibers or hard surfaces, wherein said cleaning agent contains at least one peroxy compound. Another aspect of the present invention is a process for making at a cleaning agent by combining at least one inventive solid composition with at least one bleaching agent, preferably at least one peroxy compound. Another aspect of the present inven- tion is a cleaning agent, hereinafter also being referred to as inventive cleaning agent. Inventive cleaning agents contain at least one bleaching agent and at least one inventive solid composi- tion (e. g. granule or powder). Inventive cleaning agents show a reduced tendency for yellowing and therefore have an extended shelve-life.

Examples of suitable peroxy compounds are sodium perborate, anhydrous or for example as monohydrate or as tetrahydrate or so-called dihydrate, sodium percarbonate, anhydrous or, for example, as monohydrate, hydrogen peroxide, persulfates, organic peracids such as peroxylau- ric acid, peroxystearic acid, peroxy-a-naphthoic acid, 1 ,12-diperoxydodecanedioic acid, per- benzoic acid, peroxylauric acid, 1 ,9-diperoxyazelaic acid, diperoxyisophthalic acid, in each case as free acid or as alkali metal salt, in particular as sodium salt, also sulfonylperoxy acids and cationic peroxy acids.

In a preferred embodiment, peroxy compound is selected from inorganic percarbonates, persul- fates and perborates. Examples of sodium percarbonates are 2 Na ₂ CO ₃ .3 H ₂ O ₂ . Examples of sodium perborate are ( Na ₂ [B(OH) ₂ ( O ₂ )] ₂ ), sometimes written as NaBO2-O2'3H2O instead. Most preferred peroxy compound is sodium percarbonate The term “cleaning agents” includes compositions for dishwashing, especially hand dishwash and automatic dishwashing and ware-washing, and compositions for hard surface cleaning such as, but not limited to compositions for bathroom cleaning, kitchen cleaning, floor cleaning, de- scaling of pipes, window cleaning, car cleaning including truck cleaning, furthermore, open plant cleaning, cleaning-in-place, metal cleaning, disinfectant cleaning, farm cleaning, high pressure cleaning, and in addition, laundry detergent compositions.

Such cleaning agents may be liquids, gels or preferably solids at ambient temperature, solids cleaning agents being preferred. They may be in the form of a powder or in the form of a unit dose, for example as a tablet or pouch.

In one embodiment of the present invention, inventive cleaning agents may contain in the range of from 2 to 50 % by weight of inventive solid composition and in the range of from 0.5 to 15 % by weight of bleach.

Percentages are based on the solids content of the respective inventive cleaning agent.

Inventive solid compositions are excellently suited for the manufacture of laundry detergents or cleaners.

Inventive cleaning agents may contain further ingredients such as one or more surfactants that may be selected from non-ionic, zwitterionic, cationic, and anionic surfactants. Other ingredients that may be contained in inventive cleaning agents may be selected from bleach activators, bleach catalysts, corrosion inhibitors, sequestering agents other than chelating agent (A), en- zymes, fragrances, dyestuffs, antifoams, and builders.

Particularly advantageous inventive cleaning agents may contain one or more complexing agents other than MGDA or GLDA. Advantageous detergent compositions for cleaners and ad- vantageous laundry detergent compositions may contain one or more sequestrant (chelating agent) other than a mixture according to the present invention. Examples for sequestrants other than a mixture according to the present invention are IDS (iminodisuccinate), citrate, phosphon- ic acid derivatives, for example the disodium salt of hydroxyethane-1,1-diphosphonic acid (“HEDP”), and polymers with complexing groups like, for example, polyethyleneimine in which 20 to 90 mole-% of the N-atoms bear at least one CH2COO' group, and their respective alkali metal salts, especially their sodium salts, for example IDS-Na4, and trisodium citrate, and phos- phates such as STPP (sodium tripolyphosphate). Due to the fact that phosphates raise envi- ronmental concerns, it is preferred that advantageous inventive cleaning agents are free from phosphate. "Free from phosphate" should be understood in the context of the present invention, as meaning that the content of phosphate and polyphosphate is in sum in the range from 10 ppm to 0.2% by weight, determined by gravimetric methods and referring to the respective in- ventive cleaning agent.

Inventive cleaning agents may contain one or more surfactant, preferably one or more non-ionic surfactant.

Preferred non-ionic surfactants are alkoxylated alcohols, di- and multiblock copolymers of eth- ylene oxide and propylene oxide and reaction products of sorbitan with ethylene oxide or pro- pylene oxide, alkyl polyglycosides (APG), hydroxyalkyl mixed ethers and amine oxides.

Preferred examples of alkoxylated alcohols and alkoxylated fatty alcohols are, for example, compounds of the general formula (II) in which the variables are defined as follows:

R ¹ is identical or different and selected from hydrogen and linear C ₁ -C ₁₀ -alkyl, preferably in each case identical and ethyl and particularly preferably hydrogen or methyl,

R ² is selected from C ₈ -C ₂₂ -alkyl, branched or linear, for example n-C ₈ H ₁₇ , n-C ₁₀ H ₂₁ , n-C ₁₂ H ₂₅ , n-C ₁₄ H ₂₉ , n-C ₁₆ H ₃₃ or n-C ₁₈ H ₃₇ ,

R ³ is selected from C ₁ -C ₁₀ -alkyl, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, isopentyl, sec-pentyl, neopentyl, 1,2-dimethylpropyl, isoamyl, n-hexyl, isohexyl, sec-hexyl, n-heptyl, n-octyl, 2-ethylhexyl, n-nonyl, n-decyl or isodecyl, m and n are in the range from zero to 300, where the sum of n and m is at least one, preferably in the range of from 3 to 50. Preferably, m is in the range from 1 to 100 and n is in the range from 0 to 30.

In one embodiment, compounds of the general formula (II) may be block copolymers or random copolymers, preference being given to block copolymers.

Other preferred examples of alkoxylated alcohols are, for example, compounds of the general formula (III) in which the variables are defined as follows:

R ¹ is identical or different and selected from hydrogen and linear C ₁ -C ₀ -alkyl, preferably iden- tical in each case and ethyl and particularly preferably hydrogen or methyl,

R ⁴ is selected from C ₆ -C ₂₀ -alkyl, branched or linear, in particular n-C ₈ H ₁₇ , n-C ₁₀ H ₂₁ , n-C ₁₂ H ₂₅ , n-C ₁₄ H ₂₉ , n-C ₁₆ H ₃₃ , n-C ₁₈ H ₃₇ , a is a number in the range from zero to 10, preferably from 1 to 6, b is a number in the range from 1 to 80, preferably from 4 to 20, d is a number in the range from zero to 50, preferably 4 to 25.

The sum a + b + d is preferably in the range of from 5 to 100, even more preferably in the range of from 9 to 50.

Preferred examples for hydroxyalkyl mixed ethers are compounds of the general formula (IV) in which the variables are defined as follows:

R ¹ is identical or different and selected from hydrogen and linear C ₁ -C ₁₀ -alkyl, preferably in each case identical and ethyl and particularly preferably hydrogen or methyl,

R ² is selected from C ₈ -C ₂₂ -alkyl, branched or linear, for example iso-C ₁₁ H ₂₃ , iso-C ₁₃ H ₂₇ , n- C ₈ H ₁₇ , n-C ₁₀ H ₂₁ , n-C ₁₂ H ₂₅ , n-C ₁₄ H ₂₉ , n-C ₁₆ H ₃₃ or n-C ₁₈ H ₃₇ ,

R ³ is selected from Ci-C ₁₈ -alkyl, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, isopentyl, sec-pentyl, neopentyl, 1,2-dimethylpropyl, isoamyl, n-hexyl, isohexyl, sec-hexyl, n-heptyl, n-octyl, 2-ethylhexyl, n-nonyl, n-decyl, isodecyl, n-dodecyl, n-tetradecyl, n-hexadecyl, and n-octadecyl.

The variables m and n are in the range from zero to 300, where the sum of n and m is at least one, preferably in the range of from 5 to 50. Preferably, m is in the range from 1 to 100 and n is in the range from 0 to 30.

Compounds of the general formula (II) and (III) may be block copolymers or random copoly- mers, preference being given to block copolymers.

Further suitable nonionic surfactants are selected from di- and multiblock copolymers, com- posed of ethylene oxide and propylene oxide. Further suitable nonionic surfactants are selected from ethoxylated or propoxylated sorbitan esters. Amine oxides or alkyl polyglycosides, espe- cially linear C ₄ -C ₁₆ -alkyl polyglucosides and branched Cs-Cu-alkyl polyglycosides such as com- pounds of general average formula (V) are likewise suitable. wherein the variables are defined as follows:

R ⁵ is C ₁ -C ₄ -alkyl, in particular ethyl, n-propyl or isopropyl,

R ⁶ is -(CH ₂ ) ₂ -R ⁵ ,

G ¹ is selected from monosaccharides with 4 to 6 carbon atoms, especially from glucose and xylose, y in the range of from 1 .1 to 4, y being an average number.

Further examples of non-ionic surfactants are compounds of general formula (VII) and (VIII)

AO is selected from ethylene oxide, propylene oxide and butylene oxide, EO is ethylene oxide, CH2CH2-O,

R ⁸ selected from C ₈ -C ₁₈ -alkyl, branched or linear, and R ⁵ is defined as above.

A ³ O is selected from propylene oxide and butylene oxide, w is a number in the range of from 15 to 70, preferably 30 to 50, w1 and w3 are numbers in the range of from 1 to 5, and w2 is a number in the range of from 13 to 35.

An overview of suitable further nonionic surfactants can be found in EP-A 0 851 023 and in DE- A 198 19 187.

Mixtures of two or more different nonionic surfactants may also be present.

Other surfactants that may be present are selected from amphoteric (zwitterionic) surfactants and anionic surfactants and mixtures thereof.

Examples of amphoteric surfactants are those that bear a positive and a negative charge in the same molecule under use conditions. Preferred examples of amphoteric surfactants are so- called betaine-surfactants. Many examples of betaine-surfactants bear one quaternized nitrogen atom and one carboxylic acid group per molecule. A particularly preferred example of amphoter- ic surfactants is cocam idopropyl betaine (lauramidopropyl betaine).

Examples of amine oxide surfactants are compounds of the general formula (IX)

R ⁷ R ⁸ R ⁹ N→O (IX) wherein R ⁷ , R ⁸ and R ⁹ are selected independently from each other from aliphatic, cycloaliphatic or C ₂ -C ₄ -alkylene C ₁₀ -C ₂₀ -alkylamido moieties. Preferably, R ⁷ is selected from C ₈ -C ₂₀ -alkyl or C ₂ - C ₄ -alkylene C ₁₀ -C ₂₀ -alkylamido and R ⁸ and R ⁹ are both methyl.

A particularly preferred example is lauryl dimethyl aminoxide, sometimes also called lauramine oxide. A further particularly preferred example is cocamidylpropyl dimethylaminoxide, some- times also called cocamidopropylamine oxide.

Examples of suitable anionic surfactants are alkali metal and ammonium salts of C ₈ -C ₁₈ -alkyl sulfates, of C ₈ -C ₁₈ -fatty alcohol polyether sulfates, of sulfuric acid half-esters of ethoxylated C4- Ci2-alkylphenols (ethoxylation: 1 to 50 mol of ethylene oxide/mol), C ₁₂ -C ₁₈ sulfo fatty acid alkyl esters, for example of C ₁₂ -C ₁₈ sulfo fatty acid methyl esters, furthermore of Ci2-Ci8-alkylsulfonic acids and of C ₁₀ -Cis-alkylarylsulfonic acids. Preference is given to the alkali metal salts of the aforementioned compounds, particularly preferably the sodium salts.

Further examples for suitable anionic surfactants are soaps, for example the sodium or potassi- um salts of stearoic acid, oleic acid, palmitic acid, ether carboxylates, and alkylether phos- phates.

Preferably, laundry detergent compositions contain at least one anionic surfactant.

In one embodiment of the present invention, inventive cleaning agents that are determined to be used as laundry detergent compositions may contain 0.1 to 60 % by weight of at least one sur- factant, selected from anionic surfactants, amphoteric surfactants and amine oxide surfactants.

In one embodiment of the present invention, inventive cleaning agents that are determined to be used for hard surface cleaning may contain 0.1 to 60 % by weight of at least one surfactant, selected from anionic surfactants, amphoteric surfactants and amine oxide surfactants.

In a preferred embodiment, inventive cleaning agents do not contain any anionic detergent.

Inventive cleaning agents may comprise one or more bleach catalysts. Bleach catalysts can be selected from bleach-boosting transition metal salts or transition metal complexes such as, for example, manganese-, iron-, cobalt-, ruthenium- or molybdenum-salen complexes or carbonyl complexes. Manganese, iron, cobalt, ruthenium, molybdenum, titanium, vanadium and copper complexes with nitrogen-containing tripod ligands and also cobalt-, iron-, copper- and rutheni- um-amine complexes can also be used as bleach catalysts. Inventive cleaning agents may comprise one or more bleach activators, for example N-methyl- morpholinium-acetonitrile salts (“MMA salts”), trimethylammonium acetonitrile salts, N-acyl- imides such as, for example, N-nonanoylsuccinimide, 1 ,5-diacetyl-2,2-dioxohexahydro-1 ,3,5- triazine (“DADHT”) or nitrile quats (trimethylammonium acetonitrile salts).

Further examples of suitable bleach activators are tetraacetylethylenediamine (TAED) and tetraacetylhexylenediamine.

Inventive cleaning agents may comprise one or more corrosion inhibitors. In the present case, this is to be understood as including those compounds which inhibit the corrosion of metal. Ex- amples of suitable corrosion inhibitors are triazoles, in particular benzotriazoles, bisbenzotria- zoles, aminotriazoles, alkylaminotriazoles, also phenol derivatives such as, for example, hydro- quinone, pyrocatechol, hydroxyhydroquinone, gallic acid, phloroglucinol or pyrogallol.

In one embodiment of the present invention, inventive cleaning agents comprise in total in the range from 0.1 to 1 .5% by weight of corrosion inhibitor.

Inventive cleaning agents may comprise one or more builders, selected from organic and inor- ganic builders. Examples of suitable inorganic builders are sodium sulfate or sodium carbonate or silicates, in particular sodium disilicate and sodium metasilicate, zeolites, sheet silicates, in particular those of the formula α-Na ₂ Si ₂ O ₅ , β-Na ₂ Si ₂ O ₅ , and δ-Na ₂ Si ₂ O ₅ , also fatty acid sul- fonates, a-hydroxypropionic acid, alkali metal malonates, fatty acid sulfonates, alkyl and alkenyl disuccinates, tartaric acid diacetate, tartaric acid monoacetate, oxidized starch, and polymeric builders, for example polycarboxylates and polyaspartic acid.

Examples of organic builders are especially polymers and copolymers other such as (co)polymers (B) and include polymers and copolymers than (co)polymer (B), or one additional (co)polymer (B). In one embodiment of the present invention, organic builders are selected from polycarboxylates, for example alkali metal salts of (meth)acrylic acid homopolymers or (meth)acrylic acid copolymers, partially or completely neutralized with alkali.

Suitable comonomers for (meth)acrylic acid are monoethylenically unsaturated dicarboxylic ac- ids such as maleic acid, fumaric acid, maleic anhydride, itaconic acid and citraconic acid. A suitable polymer is in particular polyacrylic acid, which preferably has an average molecular weight M _w in the range from 2000 to 40 000 g/mol, preferably 2000 to 10 000 g/mol, in particular 3000 to 8000 g/mol. Also of suitability are copolymeric polycarboxylates, in particular those of acrylic acid with methacrylic acid and of acrylic acid or methacrylic acid with maleic acid and/or fumaric acid, and in the same range of molecular weight. It is also possible to use copolymers of at least one monomer from the group consisting of monoethylenically unsaturated C ₃ -C ₁₀ -mono- or C ₄ -C ₁₀ -dicarboxylic acids or anhydrides thereof, such as maleic acid, maleic anhydride, acrylic acid, methacrylic acid, fumaric acid, itaconic acid and citraconic acid, with at least one hydrophilic or hydrophobic monomer as listed below.

Suitable hydrophobic monomers are, for example, isobutene, diisobutene, butene, pentene, hexene and styrene, olefins with 10 or more carbon atoms or mixtures thereof, such as, for ex- ample, 1 -decene, 1 -dodecene, 1 -tetradecene, 1 -hexadecene, 1 -octadecene, 1-eicosene, 1- docosene, 1-tetracosene and 1-hexacosene, C ₂₂ -α-olefin, a mixture of C ₂₀ -C ₂₄ -α-olefins and polyisobutene having on average 12 to 100 carbon atoms per molecule.

Suitable hydrophilic monomers are monomers with sulfonate or phosphonate groups, and also nonionic monomers with hydroxyl function or alkylene oxide groups. By way of example, men- tion may be made of: allyl alcohol, isoprenol, methoxypolyethylene glycol (meth)acrylate, meth- oxypolypropylene glycol (meth)acrylate, methoxypolybutylene glycol (meth)acrylate, methoxy- poly(propylene oxide-co-ethylene oxide) (meth)acrylate, ethoxypolyethylene glycol (meth)acry- late, ethoxypolypropylene glycol (meth)acrylate, ethoxypolybutylene glycol (meth)acrylate and ethoxypoly(propylene oxide-co-ethylene oxide) (meth)acrylate. Polyalkylene glycols here may comprise 3 to 50, in particular 5 to 40 and especially 10 to 30 alkylene oxide units per molecule.

Particularly preferred sulfonic-acid-group-containing monomers here are 1-acrylamido-1 -pro- panesulfonic acid, 2-acrylamido-2-propanesulfonic acid, 2-acrylamido-2-methylpropanesulfonic acid, 2-methacrylamido-2-methylpropanesulfonic acid, 3-methacrylamido-2-hydroxypropane- sulfonic acid, allylsulfonic acid, methallylsulfonic acid, allyloxybenzenesulfonic acid, methal- lyloxybenzenesulfonic acid, 2-hydroxy-3-(2-propenyloxy)propanesulfonic acid, 2-methyl-2-pro- pene-1 -sulfonic acid, styrenesulfonic acid, vinylsulfonic acid, 3-sulfopropyl acrylate, 2-sulfoethyl methacrylate, 3-sulfopropyl methacrylate, sulfomethacrylamide, sulfomethylmethacrylamide, and salts of said acids, such as sodium, potassium or ammonium salts thereof.

Particularly preferred phosphonate-group-containing monomers are vinylphosphonic acid and its salts.

A further example of builders is carboxymethyl inulin.

Moreover, amphoteric polymers can also be used as builders.

Inventive cleaning agents may comprise, for example, in the range from in total 10 to 70% by weight, preferably from in total 10 to 50% by weight, more preferably up to 20% by weight, of builder. In one embodiment of the present invention, inventive cleaning agents according to the inven- tion may comprise one or more co-builders.

Inventive cleaning agents may comprise one or more antifoams, selected for example from sili- cone oils and paraffin oils.

In one embodiment of the present invention, inventive cleaning agents comprise in total in the range from 0.05 to 0.5% by weight of antifoam.

Inventive cleaning agents may comprise one or more enzymes. Examples of enzymes are li- pases, hydrolases, amylases, proteases, cellulases, esterases, pectinases, lactases and perox- idases.

In one embodiment of the present invention, inventive cleaning agents may comprise, for ex- ample, up to 5% by weight of enzyme, preference being given to 0.1 to 3% by weight. Said en- zyme may be stabilized, for example with the sodium salt of at least one C ₁ -C ₃ -carboxylic acid or C ₄ -C ₁₀ -dicarboxylic acid. Preferred are formates, acetates, adipates, and succinates.

In one embodiment of the present invention, inventive cleaning agents may comprise at least one zinc salt. Zinc salts can be selected from water-soluble and water-insoluble zinc salts. In this connection, within the context of the present invention, water-insoluble is used to refer to those zinc salts which, in distilled water at 25°C, have a solubility of 0.1 g/l or less. Zinc salts which have a higher solubility in water are accordingly referred to within the context of the pre- sent invention as water-soluble zinc salts.

In one embodiment of the present invention, zinc salt is selected from zinc benzoate, zinc glu- conate, zinc lactate, zinc formate, ZnCl ₂ , ZnSO ₄ , zinc acetate, zinc citrate, Zn(NO ₃ ) ₂ , Zn(CH ₃ SO ₃ ) ₂ and zinc gallate, preferably ZnCl ₂ , ZnSO ₄ , zinc acetate, zinc citrate, Zn(NO ₃ ) ₂ , Zn(CH ₃ SO ₃ ) ₂ and zinc gallate.

In another embodiment of the present invention, zinc salt is selected from ZnO, ZnO aq, Zn(OH)2 and ZnCO ₃ . Preference is given to ZnO aq.

In one embodiment of the present invention, zinc salt is selected from zinc oxides with an aver- age particle diameter (weight-average) in the range from 10 nm to 100 pm.

The cation in zinc salt can be present in complexed form, for example complexed with ammonia ligands or water ligands, and in particular be present in hydrated form. To simplify the notation, within the context of the present invention, ligands are generally omitted if they are water lig- ands.

Depending on how the pH value of mixture according to the invention is adjusted, zinc salt can change. Thus, it is for example possible to use zinc acetate or ZnCl ₂ for preparing formulation according to the invention, but this converts at a pH of 8 or 9 in an aqueous environment to ZnO, Zn(OH) ₂ or ZnO aq, which can be present in non-complexed or in complexed form.

Zinc salt may be present in those inventive cleaning agents that are solid at room temperature. In such inventive cleaning agents zinc salts are preferably present in the form of particles which have for example an average diameter (number-average) in the range from 10 nm to 100 pm, preferably 100 nm to 5 μm, determined for example by X-ray scattering.

Zinc salt may be present in those inventive cleaning agents that are liquid at room temperature. In such inventive cleaning agents zinc salts are preferably present in dissolved or in solid or in colloidal form.

In one embodiment of the present invention, inventive cleaning agents comprise in total in the range from 0.05 to 0.4% by weight of zinc salt, based in each case on the dry content of the cleaning agent in question.

Here, the fraction of zinc salt is given as zinc or zinc ions. From this, it is possible to calculate the counterion fraction.

In one embodiment of the present invention, inventive cleaning agents are free from heavy met- als apart from zinc compounds. Within the context of the present, this may be understood as meaning that inventive cleaning agents are free from those heavy metal compounds which do not act as bleach catalysts, in particular of compounds of iron and of bismuth. Within the context of the present invention, "free from" in connection with heavy metal compounds is to be under- stood as meaning that the content of heavy metal compounds which do not act as bleach cata- lysts is in sum in the range from 0 to 100 ppm, determined by the leach method and based on the dry content. Preferably, inventive cleaning agents has, apart from zinc, a heavy metal con- tent below 0.05 ppm, based on the dry content of the formulation in question. The fraction of zinc is thus not included.

Within the context of the present invention, "heavy metals" are deemed to be all metals with a specific density of at least 6 g/cm ³ with the exception of zinc. In particular, the heavy metals are metals such as bismuth, iron, copper, lead, tin, nickel, cadmium and chromium. Preferably, inventive cleaning agents comprise no measurable fractions of bismuth compounds, for example less than 1 ppm.

Inventive cleaning agents are excellent for cleaning hard surfaces and fibres. For example, they may be used in dishwashing applications, preferably automatic dishwashing applications.

In one embodiment of the present invention, inventive cleaning agents comprise one or more further ingredient such as fragrances, dyestuffs, organic solvents, buffers, disintegrants for tab- lets (“tabs”), and/or acids such as methylsulfonic acid.

From inventive solid compositions, e. g. granules or powders, exemplary detergent composi- tions for automatic dishwashing detergents can be formulated by mixing the respective compo- nents according to the following Table F.

Table F: Example detergent compositions for automatic dishwashing

Laundry detergents according to the invention are useful for laundering any type of laundry, and any type of fibres. Fibres can be of natural or synthetic origin, or they can be mixtures of natural of natural and synthetic fibres. Examples of fibers of natural origin are cotton and wool. Exam- ples for fibers of synthetic origin are polyurethane fibers such as Spandex® or Lycra®, polyester fibers, or polyamide fibers. Fibers may be single fibers or parts of textiles such as knitwear, wovens, or nonwovens. Another aspect of the present invention is a process for making tablets for automatic dishwash- ing from an inventive solid composition, e. g. a powder or granule, wherein said granule or pow- der is selected from inventive granules and inventive powders, respectively. Said process is hereinafter also referred to as pelletizing process according to the invention.

Inventive tablets are preferably made with the help of a machine, for example a tablet press. The pelletizing process according to the invention can be carried out by mixing an inventive sol- id composition, e. g. granule or powder, with at least one non-ionic surfactant and optionally one or more further substance and then compressing the mixture to give tablets. Examples of suita- ble non-ionic surfactants and further substances such as builders, enzymes are listed above.

Particularly preferred examples of non-ionic surfactants are hydroxy mixed ethers, for example hydroxy mixed ethers of the general formula (V).

The invention is further illustrated by the following, non-limiting working examples.

Working examples . Re-crystallization experiments

1.1 Samples:

(M.1) sodium salt of MGDA agglomerate

(M.2) sodium salt of MGDA amorphous powder

(M.3) sodium salt of MGDA orthorhombic powder

(M.4) mixture of sodium salt of MGDA amorphous powder and sodium salt of MGDA ortho- rhombic powder; (M.4) is a mixture of 50 % by weight (M.2) and 50 % by weight (M.3). 10 g of each product were placed in a ceramic dish and then grinded together.

1 .2 Composition of samples:

(C.1) percentage of monoclinic alkali metal salt of MGDA

(C.2) percentage of orthorhombic alkali metal salt of MGDA

(C.3) percentage of crystalline salt of MGDA

(C.4) percentage of amorphous salt of MGDA

(W.1) percentage of monoclinic alkali metal salt of MGDA in whole sample

(W.2) percentage of orthorhombic alkali metal salt of MGDA in whole sample

The percentages of (C.1), (C.2), (C.3) and (C.4) were determined by X-ray diffraction (Table 1). (The measuring and evaluation methods are described below.) Table 1 : Measurement results of composition of the samples before re-crystallization

The data on the proportions of (C.1) and (C.2) refer to (C.3). Based on this measurement data, the proportion of (C.1) and (C.2) in the whole sample was calculated by formula (1) (results in Table 2).

Table 2: Calculated data of composition of the samples before re-crystallization

1.3 Re-crystallization experiment

15 g of each sample or each mixture was placed in a petri dish with 100 mm diameter. The petri dish has not been closed to allow an exchange with the surrounding atmosphere. The petri dish was stored for 2 hours in a climate chamber at 35 °C and 70 % humidity. Afterwards the X-ray diffraction was determined (Table 3).

Table 3: Measurement results of composition of the samples after re-crystallization

Based on this measurement data, the proportion of (C.1) and (C.2) in the whole sample was calculated by formula (1) (results in Table 4).

Table 4: Calculated data of composition of the samples after re-crystallization

The experiments clearly show that, surprisingly, the degree of crystallinity in the samples and/or the content of orthorhombic MGDA salt increase when the inventive process is used. All sam- ples after re-crystallization show superior results in storage tests.

Re-crystallization experiment pilot plant trial

All samples were produced by spray drying, and agglomerates were formed. Before further treatment one sample was taken (V.1; V.3; V.5). Afterwards the samples were split into two parts.

The second part was added to a mixer. Then in summary 7% distilled water was sprayed on the samples at 70°C while the samples were stirred continuously. After adding the required amount water, the mixture was stirred for further 3 minutes. Then the mixture was compacted with 20 kN and milled to < 1 mm (V.2; V.4; V.6).

2.1 Samples

(V.1) sodium salt of MGDA agglomerate

(V.2) sodium salt of MGDA agglomerate after re-crystallization

(V.3) sodium salt of MGDA agglomerate

(V.4) sodium salt of MGDA agglomerate after re-crystallization (V.5) sodium salt of MGDA (94%) + sulfonated acrylic polymer (6%) agglomerate

(V.6) sodium salt of MGDA (94%) + sulfonated acrylic polymer (6%) agglomerate after re- crystallization 2.2 Composition of samples:

(C.1) percentage of monoclinic alkali metal salt of MGDA

(C.2) percentage of orthorhombic alkali metal salt of MGDA

(C.3) percentage of crystalline salt of MGDA

(C.4) percentage of amorphous salt of MGDA (W.1) percentage of monoclinic alkali metal salt of MGDA in whole sample

(W.2) percentage of orthorhombic alkali metal salt of MGDA in whole sample

The percentages of (C1), (C2), (C3) and (C4) were determined by X-ray diffraction (Table 1).

Table 5: Measurement results of composition of the samples

The data on the proportions of (C.1) and (C.2) refer to (C.3). Based on this measurement data, the proportion of (C.1) and (C.2) in the whole sample was calculated by formula (1) (results in Table 2).

Table 6: Calculated data of composition of the samples . Testing

3 .1 Samples:

(B.1) Benchmark commercially available granules from BASF of monoclinic alkali metal salt of MGDA

(V.1) sodium salt of MGDA agglomerate

(V.2) sodium salt of MGDA agglomerate after re-crystallization

(V.3) sodium salt of MGDA agglomerate

(V.4 sodium salt of MGDA agglomerate after re-crystallization

(V.5) sodium salt of MGDA (94%) + sulfonated polymer (6%) agglomerate

(V.6) sodium salt of MGDA (94%) + sulfonated polymer (6%) agglomerate after re-crystallization

3.3 Discoloration in ADW formulation as tablets

1.88 g of the samples were mixed with 12.53g of a typically ADW formulation and pressed to a tablet with 100kN. Then the tablets were packed in a LD-PE Bag. The tablets were stored for 9 weeks in a climate-chamber at 35°C and 70% humidity.

The discoloration - which is a yellowing in this case - of the stored mixtures was determined by measuring the b-value of the CIELAB color space (Mach5 measurement).

Discoloration Test:

(D.1): start value

(D.2): discoloration after storage for 9 weeks (delta to previous measurement)

(D.3): total discoloration

The results are summarized in Table 7.

Table 7: Discoloration behavior

Humidity experiments on crystalline mixtures

The humidity XRD experiments were performed using an Anton Paar CHC plus cryo and humid- ity chamber mounted on a Bruker D8 Advance. The data were collected using Cu Kai radiation using a primary Johansson type monochromator. To ensure high time resolution the detector (Lynxeye, Bruker AXS) was set to a fixed position to detect the angular range of 7.5° to 9°(2θ). The humidity and temperature were set and the first data were collected on reaching these set points. The data collection was performed for ten hours per experiment.

The samples were prepared by taking phase pure samples of monoclinic form (Form I) and or- thorhombic form (Form II) and preparing these for XRD by light manual grinding. The samples were then carefully homogenized by shaking the weighed fractions in a closed sample bottle for 30 seconds. This mixture was then filled into the sample holder and flattened using a glass plate.

All fitting procedures were performed using TOPAS 6 ¹ . The data were analyzed using the two distinct reflections discerning monoclinic form (Form I), at approximately 8.13°(2θ) and ortho- rhombic form (Form II), at approximately 8.27°(2θ) of Na ₃ -MGDA. The separation of the two modelled reflections was constrained to O.139°(2θ). The crystallite size broadening was refined using a Voigt model and was fixed to 106nm determined using the integral breadth method. The intensities were related to their corrected scattering factors determined using the standard Rietveld approach. No correction for preffered orientation was applied. This resulted in the re- flection intensity ratio of 2.305 for Form l:Form II. The resulting volume fraction is then deter- mined using the following equation: Where I ₁ is the intensity of the first reflection related to Form I and I2 is the second reflection related to Form II. Form II then is then the complementary:

Figure 1 to 7

The data show clearly the advantageous effect of the elevated humidity in the conversion to the orthorhombic structure

Humidity experiments on crystalline/amorphous mixture

For determination of the recrystallisation of the amorphous material into orthorhombic form (Form II) the amorphous content was estimated using an internal standard method ² . 10 mass% of Corundum was added to the sample and then the relative intensities of Corundum versus Form II used to analyze the recrystallization. The data collection was altered to the angular range of 23° to 26°(2θ). Here two reflections are fit to the data. The first reflection at approxi- mately 23.6°(2θ) is related to Form II whereas the reflection at 25.4°(2θ) is related to Corundum. The temperature and humidity is set and data collected over the same time as the crystalline samples. The initial intensity ratio is used to calibrate the 50% Form II volume fraction. In the subsequent data sets the Form II fraction is determined usign the following ratio:

Where I _ill is the intensity of the first reflection of the first dataset related to the Form II and I _iC or is the intensity of the second reflection of the first dataset related to the Corundum standard.

Quantification via XRD -

XRD data are collected in a Bruker D8 Advance Bragg-Brentano diffractometer with Cu-Ka ra- diation (A=1.54A). The angular range is set to 2-80° (2θ) with a step size of 0.02° (2θ). The inci- dent divergent beam slit is set to 0.1 °. A Lynxeye detector is used with an opening angle of 3°. Data collection time is optimized to ensure a maximum peak height greater than 50'000 counts per step. The data are then analyzed using a Rietveld model containing the crystal structures of orthorhombic and monoclinic forms of Na ₃ -MGDA-dihydrate. The instrumental contribution to the line broadening is calculated using the fundamental parameter approach ^1,2 as it is imple- merited within the software TOPAS 6 ¹ . A third order polynomial and a 1/X function are used to model the background. The mass percent values are as reported within the TOPAS user inter- face. References:

1. TOPAS 6 Technical Reference. Bruker AXS GmbH: 2017.

2. Dinnebier, R. E.; Billinge, S. J., Powder diffraction: theory and practice. Royal society of chemistry: 2008.

Figure 8

The data again show clearly the advantageous effect of the elevated humidity in the conversion to the orthorhombic structure.