POWDERS AND GRANULES AND PROCESS FOR MAKING SUCH POWDERS AND GRANULES

Abstract

The present invention is directed towards a process for making a powder or granule containing (A) at least one alkali metal salt of citric acid, and at least one additive selected from (B) at least one (co)polymer containing carboxylic acid groups, partially neutralized with alkali, in a weight ratio of (A):(B) of from 5:1 up to 100:1, wherein said powder or granule contains at least 75% by weight of citrate (A), said process comprising the steps of (a) mixing the at least one alkali metal salt of citric acid (A) and the at least one (co)polymer (B) in the presence of water, (b) removing most of said water by spray-drying or spray granulation using a gas with an inlet temperature of at least 125° C.

Claims

1. A process for making a powder or granule containing (A) at least one alkali metal salt of citric acid, and at least one additive selected from (B) (co)polymer(s) comprising carboxylic acid groups, partially neutralized with alkali, in a weight ratio of (A):(B) of from 5:1 up to 100:1, wherein said powder or granule contains at least 75% by weight of citrate (A), referring to the solids content of said powder or granule, said process comprising the steps of (a) mixing the at least one alkali metal salt of citric acid (A) and the at least one (co)polymer (B) in the presence of water, and (b) removing most of said water by spray-drying or spray granulation using a gas with an inlet temperature of at least 125° C.

2. The process according to claim 1, wherein (A) is trisodium salt of citric acid.

3. (canceled)

4. (canceled)

5. (canceled)

6. The process according to claim 1 wherein (co)polymer (B) is selected from polyacrylic acid, random copolymers of acrylic acid with maleic anhydride or 2-acrylamido-2-methylpropanesulfonic acid, each (co)polymer being partially selected with alkali.

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

8. A powder or granule comprising (A) at least one alkali metal salt of citric acid, and at least one additive selected from (B) (co)polymer(s) comprising carboxylic acid groups, partially neutralized with alkali, in a weight ratio of (A):(B) of from 5:1 up to 100:1, in molecularly disperse form, wherein said powder or granule contains at least 75% by weight of citrate (A), referring to the solids content of said powder or granule.

9. The powder or granule according to claim 8, having a residual moisture content in the range of from 0.1 to 20% by weight.

10. The powder according to claim 8, having an average particle diameter in the range of from 1 μm to less than 0.1 mm.

11. The granules according to claim 8, having an average particle diameter in the range of from 0.1 mm to 2 mm.

12. (canceled)

13. The powder or granule according to claim 8, wherein (A) is trisodium salt of citric acid.

14. (canceled)

15. (canceled)

16. The powder or granule according to claim 8, wherein said wherein (co)polymer (B) is selected from polyacrylic acid, random copolymers of acrylic acid with maleic anhydride or 2-acrylamido-2-methylpropanesulfonic acid, each (co)polymer being partially selected with alkali.

17. A method for the manufacture of a cleaning agent for fibers or hard surfaces comprising combining a powder or granule according to claim 8 with at least one bleaching agent, wherein said cleaning agent comprises at least one peroxy compound selected from percarbonates, persulfates or perborates.

Description

[0146] Examples of amine oxide surfactants are compounds of the general formula (VI)

R.sup.7R.sup.8R.sup.9N.fwdarw.O  (VI)

wherein R.sup.7, R.sup.5 and R.sup.9 are selected independently from each other from aliphatic, cycloaliphatic or C.sub.2-C.sub.4-alkylene C.sub.10-C.sub.20-alkylamido moieties. Preferably, R.sup.7 is selected from C.sub.8-C.sub.20-alkyl or C.sub.2-C.sub.4-alkylene C.sub.10-C.sub.20-alkylamido and R.sup.5 and R.sup.9 are both methyl.

[0147] A particularly preferred example is lauryl dimethyl aminoxide, sometimes also called lauramine oxide. A further particularly preferred example is cocamidylpropyl dimethylaminoxide, sometimes also called cocamidopropylamine oxide.

[0148] Examples of suitable anionic surfactants are alkali metal and ammonium salts of C.sub.8-C.sub.18-alkyl sulfates, of C.sub.8-C.sub.18-fatty alcohol polyether sulfates, of sulfuric acid half-esters of ethoxylated C.sub.4-C.sub.12-alkylphenols (ethoxylation: 1 to 50 mol of ethylene oxide/mol), C.sub.12-C.sub.18 sulfo fatty acid alkyl esters, for example of C.sub.12-C.sub.18 sulfo fatty acid methyl esters, furthermore of C.sub.12-C.sub.18-alkylsulfonic acids and of C.sub.10-C.sub.18-alkylarylsulfonic acids. Preference is given to the alkali metal salts of the aforementioned compounds, particularly preferably the sodium salts.

[0149] Further examples for suitable anionic surfactants are soaps, for example the sodium or potassium salts of stearoic acid, oleic acid, palmitic acid, ether carboxylates, and alkylether phosphates.

[0150] Preferably, laundry detergent compositions contain at least one anionic surfactant.

[0151] 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 surfactant, selected from anionic surfactants, amphoteric surfactants and amine oxide surfactants.

[0152] 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.

[0153] In a preferred embodiment, inventive cleaning agents do not contain any anionic detergent.

[0154] 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 ruthenium-amine complexes can also be used as bleach catalysts.

[0155] Inventive cleaning agents may comprise one or more bleach activators, for example N-methylmorpholinium-acetonitrile salts (“MMA salts”), trimethylammonium acetonitrile salts, N-acylimides such as, for example, N-nonanoylsuccinimide, 1,5-diacetyl-2,2-dioxohexahydro -1,3,5-triazine (“DADHT”) or nitrile quats (trimethylammonium acetonitrile salts).

[0156] Further examples of suitable bleach activators are tetraacetylethylenediamine (TAED) and tetraacetylhexylenediamine.

[0157] 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. Examples of suitable corrosion inhibitors are triazoles, in particular benzotriazoles, bisbenzotriazoles, aminotriazoles, alkylaminotriazoles, also phenol derivatives such as, for example, hydroquinone, 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.

[0158] Inventive cleaning agents may comprise one or more additional builders, selected from organic and inorganic builders. Examples of suitable inorganic builders are sodium sulfate or sodium carbonate, zeolites, sheet silicates, in particular those of the formula α-Na.sub.2Si.sub.2O.sub.5, β-Na.sub.2Si.sub.2O.sub.5, and δ-Na.sub.2Si.sub.2O.sub.5, also fatty acid sulfonates, α-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 than (co)polymer (B), or one additional copolymer (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.

[0159] Suitable comonomers for (meth)are monoethylenically unsaturated dicarboxylic acids 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.sub.w in the range from 2000 to 40 000 g/mol, preferably 3,000 to 10,000 g/mol.

[0160] It is also possible to use copolymers of at least one monomer from the group consisting of monoethylenically unsaturated C.sub.3-C.sub.10-mono- or C.sub.4-C.sub.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.

[0161] 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 example, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, 1-eicosene, 1-docosene, 1-tetracosene and 1-hexacosene, C.sub.22-α-olefin, a mixture of C.sub.20-C.sub.24-α-olefins and polyisobutene having on average 12 to 100 carbon atoms per molecule.

[0162] 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, mention may be made of: allyl alcohol, isoprenol, methoxypolyethylene glycol (meth)acrylate, methoxypolypropylene glycol (meth)acrylate, methoxypolybutylene glycol (meth)acrylate, methoxypoly(propylene oxide-co-ethylene oxide) (meth)acrylate, ethoxypolyethylene glycol (meth)acrylate, 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.

[0163] Particularly preferred sulfonic-acid-group-containing monomers here are 1-acrylamido -1-propanesulfonic acid, 2-acrylamido-2-propanesulfonic acid, 2-acrylamido -2-methylpropanesulfonic acid, 2-methacrylamido-2-methylpropanesulfonic acid, 3-methacrylamido-2-hydroxypropanesulfonic acid, allylsulfonic acid, methallylsulfonic acid, allyloxybenzenesulfonic acid, methallyloxybenzenesulfonic acid, 2-hydroxy -3-(2-propenyloxy)propanesulfonic acid, 2-methyl-2-propene-1-sulfonic acid, styrenesulfonic acid, vinylsulfonic acid, 3-sulfopropyl acrylate, 2-sulfoethyl methacrylate, 3-sulfopropyl methacry-late, sulfomethacrylamide, sulfomethylmethacrylamide, and salts of said acids, such as sodium, potassium or ammonium salts thereof.

[0164] Particularly preferred phosphonate-group-containing monomers are vinylphosphonic acid and its salts.

[0165] Moreover, amphoteric polymers can also be used as builders.

[0166] Inventive cleaning agents may comprise, for example, in the range from in total 10 to 50% by weight, preferably up to 20% by weight, of builder.

[0167] In one embodiment of the present invention, inventive cleaning agents according to the invention may comprise one or more cobuilders.

[0168] Inventive cleaning agents may comprise one or more antifoams, selected for example from silicone oils and paraffin oils.

[0169] 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.

[0170] Inventive cleaning agents may comprise one or more enzymes. Examples of enzymes are lipases, hydrolases, amylases, proteases, cellulases, esterases, pectinases, lactases and peroxidases.

[0171] In one embodiment of the present invention, inventive cleaning agents may comprise, for example, up to 5% by weight of enzyme, preference being given to 0.1 to 3% by weight. Said enzyme may be stabilized, for example with the sodium salt of at least one C.sub.1-C.sub.3-carboxylic acid or C.sub.4-C.sub.10-dicarboxylic acid. Preferred are formates, acetates, adipates, and succinates.

[0172] 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 present invention as water-soluble zinc salts. In one embodiment of the present invention, zinc salt is selected from zinc benzoate, zinc gluconate, zinc lactate, zinc formate, ZnCl.sub.2, ZnSO.sub.4, zinc acetate, zinc citrate, Zn(NO.sub.3).sub.2, Zn(CH.sub.3SO.sub.3).sub.2 and zinc gallate, preferably ZnCl.sub.2, ZnSO.sub.4, zinc acetate, zinc citrate, Zn(NO.sub.3).sub.2, Zn(CH.sub.3SO.sub.3).sub.2 and zinc gallate.

[0173] In another embodiment of the present invention, zinc salt is selected from ZnO, ZnO.aq, Zn(OH).sub.2 and ZnCO.sub.3. Preference is given to ZnO.aq.

[0174] In one embodiment of the present invention, zinc salt is selected from zinc oxides with an average particle diameter (weight-average) in the range from 10 nm to 100 μm. 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 ligands.

[0175] 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.sub.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).sub.2 or ZnO.aq, which can be present in non-complexed or in complexed form.

[0176] 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 μm, preferably 100 nm to 5 μm, determined for example by X-ray scattering.

[0177] 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.

[0178] 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 solids content of the cleaning agent in question.

[0179] Here, the fraction of zinc salt is given as zinc or zinc ions. From this, it is possible to calculate the counterion fraction.

[0180] In one embodiment of the present invention, inventive cleaning agents are free from heavy metals 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 understood as meaning that the content of heavy metal compounds which do not act as bleach catalysts is in sum in the range from 0 to 100 ppm, determined by the leach method and based on the solids content. Preferably, inventive cleaning agents has, apart from zinc, a heavy metal content below 0.05 ppm, based on the solids content of the formulation in question. The fraction of zinc is thus not included.

[0181] 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.sup.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, i.e. for example less than 1 ppm.

[0182] Inventive cleaning agents are excellent for cleaning hard surfaces and fibres.

[0183] The present invention is further illustrated by working examples.

[0184] General remarks: The bulk density was determined in accordance with ISO 697 (2.sup.nd edition 1981-03-01).

[0185] NI: Norm liter, liters under normal conditions; Nm.sup.3: norm cubic meter, cubic meter under normal conditions. Unless expressly indicated otherwise, percentages are % by weight.

[0186] Starting Materials: [0187] (A.1): trisodium salt of citric acid [0188] (B.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 [0189] (B.2): polyacrylic acid, fully neutralized with sodium hydroxide, M.sub.w: 4,000 g/mol, determined by GPC and referring to the free acid, as 45% by weight aqueous solution [0190] (C.1): sodium silicate, a sodium water glass, weight ratio SiO.sub.2/Na.sub.2O: 2.04, solids content 48.5%, density: 1.6 g/cm.sup.3.

[0191] The molecular weight of polymers (B.1) and (B.2) was determined by GPC. Said measurements were performed at a pH value of 7.4 (phosphate buffer), stationary phase: cross-linked poly-acrylate, mobile phase: water, pH value 7.4, phosphate buffer with 0.01 M NaN.sub.3.

[0192] The calcium binding capacity was determined by titration with CaCl.sub.2 solution: a glass beaker is charged with 1 g of granule dissolved in 100 ml demineralized water. Then, 2 ml of the 10% by weight sodium carbonate solution are added and set to a pH value of 11 ±0.2 with NaOH (1 mol/L) or HCI (1 mol/L). Standard titration parameters for polymers are at 25° C. and pH 11. The solution was clear and colorless. The optrode is set to 660 nm and put into the glass beaker.

[0193] I. Manufacture of Spray Liquors

[0194] I.1 Manufacture of Spray Liquor SL.1, Step (a.1)

[0195] A vessel was charged with 14.629 kg of an aqueous solution of (A.1) (40% by weight). An amount of 124 g of a 48.5% by weight aqueous solution of (C.1) and 246 g of a 49% by weight aqueous solution (B.1) was added. The spray liquor SL.1 so obtained was stirred vigorously and then heated to 70° C. for 3 hours and then subjected to spray granulation.

[0196] I.2 Manufacture of Spray Liquor SL.2, Step (a.2)

[0197] A vessel was charged with 15.28 kg of an aqueous solution of (A.1) (40% by weight) and 720 g of an aqueous solution of (B.1) (45% by weight). The spray liquor SL.2 so obtained was stirred vigorously and then heated to 70° C. and subjected to spray granulation.

[0198] I.3 Manufacture of Spray Liquor SL.3, Step (a.3)

[0199] A vessel was charged with 15.5 kg of an aqueous solution of (A.1) (40% by weight) and 750 g of an aqueous solution of (B.2) (40% by weight). The spray liquor SL.3 so obtained was stirred and then heated to 70° C. and subjected to spray granulation.

[0200] II Spray Granulation

[0201] II.1 Spray Granulation of Spray Liquor SL.1, Step (b.1)

[0202] A lab scale granulator, commercially available as Glatt Procell Lab System with Vario 3 Insert, is charged with 0.9 kg of solid trisodium citrate spherical particles, diameter 350 to 1000 μm, and 600 g of milled trisodium citrate particles. An amount of 200 Nm.sup.3/h of air with a temperature of 165 to 168° C. is blown from the bottom. A fluidized bed of trisodium citrate particles is obtained. The above spray liquor SL.1 is introduced by spraying 6 kg of SL.1 (70° C.) per hour into the fluidized bed from the bottom through a two-fluid nozzle, absolute pressure in the nozzle: 4 bar. Granules are formed, and the bed temperature, which corresponds to the surface temperature of the solids in the fluidized bed, is 95 to 101° C.

[0203] Particles that were large (heavy) enough fall through the zigzag air classifier (operated at 1.8 to 2 bar relative pressure) are continuously transferred into a sample bottle. The smaller (lighter) granules are blown through the recycle back into the fluidized bed by the air classifier.

[0204] When about 1 L of granules were collected in the sample bottle, the bottle is replaced by a new sample bottle. The collected granules were subjected to a sieving step, mesh size 1 mm. Two fractions were obtained: coarse particles (diameter>1 mm) and value fraction (<1 mm). Coarse particles (diameter>1 mm), were milled down together with small amounts of value fraction using a hammer mill (Kinetatica Polymix PX-MFL 90D) at 4000 rounds per minute (rpm), 2 mm mesh. The powder so obtained was returned into the fluidized bed. The major part of the value fraction, which was not milled down, left the process and was collected.

[0205] After consumption of 12 kg of SL.1 a steady state is reached. Then, the fraction <1 mm is collected as inventive granules Gr.1.

[0206] The residual moisture of Gr.1 is determined to be 11.5%, referring to the total solids content of the granule and determined by Karl-Fischer titration.

[0207] In the above example, hot air of 170° C. can be replaced by hot N.sub.2 having a temperature of

[0208] The inventive granule Gr.1 has an excellent iron and calcium binding capacity combined with low hygroscopicity and low tendency of yellowing.

[0209] II.2 Spray Granulation of Spray Liquor SL.2, Step (b.2)

[0210] When experiment under II.1 is essentially repeated but with SL.2 instead of SL.1 and under similar parameter for the spray granulation, inventive granule Gr.2 is obtained, with low hygroscopicity and low tendency of yellowing but high iron and calcium binding capacity.

[0211] II.3 Spray Granulation of Spray Liquor SL.3, Step (b.3)

[0212] When experiment under II.1 is essentially repeated but with SL.3 instead of SL.1 and under similar parameter for the spray granulation, inventive granule Gr.3 is obtained, with low hygroscopicity and low tendency of yellowing but high iron and calcium binding capacity.

[0213] II.4 Spray Granulation of an Aqueous Solution of (A.1)

[0214] When experiment under II.1 is essentially repeated but with an aqueous solution of (A.1) with a concentration as in SL.1—but neither (B.1) nor (B.1) nor (B.2)—instead of SL.1 and under similar parameter for the spray granulation, comparative granule C-Gr.4 is obtained, with comparatively low iron and calcium binding capacity.

[0215] From inventive granules, example detergent compositions for automatic dishwashing detergents can be formulated by mixing the respective components according to Table 1.

TABLE-US-00001 TABLE 1 Example detergent compositions for automatic dishwashing All amounts in g/sample ADW.1 ADW.2 ADW.3 either of Gr.1, Gr.2, Gr.3 or C-Gr.4 30 22.5 15 Protease 2.5 2.5 2.5 Amylase 1 1 1 n-C.sub.18H.sub.37—O(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 HEDP 0.5 0.5 0.5 ethoxylated polyethylenimine, 20 optionally: optionally: optionally: EO/NH group, M.sub.n: 30,000 g/mol 0.1 0.1 0.1