METHOD FOR PRODUCING A PARTICULATE CARRIER MATERIAL PROVIDED WITH ELEMENTARY SILVER AND ELEMENTARY RUTHENIUM

Abstract

The invention relates to a method for producing a particulate carrier material provided with silver and ruthenium, comprising the following steps: a) providing a water-insoluble particulate carrier material and aqueously dissolved silver and ruthenium precursors, b) bringing the particulate carrier material into contact with the aqueous solution of the precursors to form an intermediate, c) bringing the intermediate into contact with an aqueous hydrazine solution having a pH of >7 to 14 to form a mass comprising silver and ruthenium, d) optionally washing the obtained mass, and e) removing water and other possible volatile components from the mass.

Claims

1. A method for producing a particulate carrier material provided with elemental silver and elemental ruthenium, comprising the following successive steps: a) providing a water-insoluble particulate carrier material and (i) an aqueous solution A comprising dissolved silver precursors and an aqueous solution B comprising dissolved ruthenium precursors or (ii) an aqueous solution C comprising both dissolved silver precursors and dissolved ruthenium precursors, b) bringing the water-insoluble particulate carrier material into contact (i) with aqueous solution A and aqueous solution B or preferably (ii) with aqueous solution C to form an intermediate, preferably an intermediate in the form of a free-flowing impregnated particulate material, c) bringing the intermediate into contact with an aqueous solution comprising a pH in the range of >7 to 14 and comprising hydrazine, to form a mass comprising elemental silver and elemental ruthenium, d) optionally washing the mass obtained after completion of step c), and e) removing water and other possible volatile components from the mass obtained after completion of step c) or d).

2. The method according to claim 1, wherein the intermediate is a free-flowing impregnated particulate material.

3. The method according to claim 2, wherein the free-flowing impregnated particulate material has the form of grains or flakes impregnated (i) with aqueous solution A and aqueous solution B or preferably (ii) with aqueous solution C.

4. The method according to claim 2, wherein the free-flowing impregnated particulate material has an avalanche angle in the range of 40 to 80 degrees, determined by means of rotary powder analysis with 100 mL of the free-flowing impregnated particulate material using the Revolution Powder Analyzer from PS Prozesstechnik GmbH at 0.5 rpm and using a cylinder with an internal depth of 35 mm and an internal diameter of 100 mm at 20° C.

5. The method according to claim 4, wherein the free-flowing impregnated particulate material is further characterized by a period between two avalanches in the range from 2 to 5 seconds.

6. The method according to claim 1, wherein the water-insoluble particulate carrier material is swellable with water or is capable of forming a hydrogel.

7. The method according to claim 1, wherein the material of the water-insoluble particulate carrier material is selected from the group consisting of glass, nitrides, high-melting oxides, silicates, plastics, modified or unmodified polymers of natural origin, carbon substrates and wood.

8. The method according to claim 1, wherein the water-insoluble particulate carrier material is cellulose powder.

9. The method according to claim 1, wherein the silver precursors and ruthenium precursors are one or more silver(I) compounds and one or more ruthenium compounds selected from the group consisting of ruthenium(II) compounds, ruthenium(III) compounds and ruthenium(IV) compounds.

10. The method according to claim 1, wherein the silver:ruthenium weight ratio in the combination of aqueous solutions A and B used in step b) or in aqueous solution C is in the range from 1 to 2000 parts by weight of silver:1 part by weight of ruthenium.

11. The method according to claim 1, wherein the silver plus ruthenium weight fraction in the aqueous solution C is in the range from 0.5-20 wt %.

12. The method according to claim 1, wherein the hydrazine concentration of the aqueous hydrazine solution is in the range from 0.1 to 5 wt %.

13. The method according to claim 1, wherein the aqueous hydrazine solution is brought into contact with the intermediate in a stoichiometrically required amount, or more, for complete reduction of the silver and ruthenium precursors contained in the intermediate.

14. A particulate carrier material provided with elemental silver and elemental ruthenium and produced according to a method of claim 1.

15. The particulate carrier material provided with elemental silver and elemental ruthenium according to claim 14, with a silver plus ruthenium weight fraction in the range from 0.1 to 50 wt % at a silver:ruthenium weight ratio in the range from 1 to 2000 parts by weight of silver:1 part by weight of ruthenium.

16. A use of a particulate carrier material provided with elemental silver and elemental ruthenium according to claim 14 as an additive for antimicrobial finishing of: metal surfaces; coating agents; plasters, molding compounds; plastics in the form of plastics films, plastics parts or plastics fibers; synthetic resin products; ion exchange resins; silicone products; cellulose-based products; foams; textiles; cosmetics and hygiene articles.

17. The use according to claim 16, wherein the cellulose-based products are selected from the group consisting of paper products, cardboards, wood fiber products and cellulose acetate.

18. The use according to claim 16, wherein the plastics are selected from the group consisting of ABS plastic, PVC, polylactic acid, PU, poly(meth)acrylate, PC, polysiloxane, phenol formaldehyde resin, melamine formaldehyde resin, polyester, polyamide, polyether, polyolefin, polystyrene, hybrid polymers thereof, and mixtures thereof.

Description

Exemplary Embodiment 1 (Production of a Cellulose Powder Provided With 18.3 wt % of Elemental Silver and 0.2 wt % of Elemental Ruthenium)

[0063] 132.45 g of aqueous silver nitrate solution (silver content 36.24 wt %; 445 mmol Ag) and 2.60 g of aqueous ruthenium nitrosylnitrate solution (ruthenium content 19.0 wt %; 4.9 mmol Ru) were added to 364.5 g of demineralized water, and the aqueous precursor solution obtained in this way was mixed homogeneously with 211.2 g of cellulose powder (Vitacel® L-600 from J. Rettenmaier and Sohne GmbH & Co KG) to give an orange, free-flowing impregnated particulate material. 100 mL of this material were subjected to rotary powder analysis at 20° C. by means of the Revolution Powder Analyzer from PS Prozesstechnik GmbH, Neuhausstrasse 36, CH-4057 Basel at 0.5 rpm and using a cylinder with an internal depth of 35 mm and an internal diameter of 100 mm; the frame rate was 10 images per second and 300 avalanches were recorded. The avalanche angle determined in this way was 75 degrees and the duration between two avalanches was 3.6 seconds. To the free-flowing impregnated particulate material, at room temperature, 705 mL of an aqueous hydrazine solution having a pH of 14 [3.68 g (115 mmol) of hydrazine and 71.82 g of a 32 wt % sodium hydroxide solution (575 mmol NaOH), remainder: water] were added at a metering rate of 30 mL/min with stirring. Over time, a black homogeneous pulp which became increasingly easy to stir was formed. After completion of the metered addition, stirring was continued for 30 minutes until no more nitrogen release could be observed. Subsequently, the material was strained off, washed with a total of 1000 mL of water and dried in a drying cabinet at 105° C./300 mbar to a residual moisture content of 15 wt %. By means of ICP-OES, a silver content of 18.3 wt % and a ruthenium content of 0.19 wt % of the end product (based on 0 wt % of residual moisture) were determined.

Exemplary Embodiment 2 (Production of a Cellulose Powder Provided With 10.9 wt % of Elemental Silver and 0.2 wt % of Elemental Ruthenium)

[0064] 97.96 g of aqueous silver nitrate solution (silver content 36.24 wt %; 329 mmol Ag) and 3.68 g of aqueous ruthenium nitrosylnitrate solution (ruthenium content 19.0 wt %; 6.9 mmol Ru) were added to 554.9 g of demineralized water, and the aqueous precursor solution obtained in this way was mixed homogeneously with 299.2 g of cellulose powder (Vitacel® L-600 from J. Rettenmaier and Sohne GmbH & Co KG) to give an orange, free-flowing impregnated particulate material. 100 mL of this material were subjected to rotary powder analysis at 20° C. by means of the Revolution Powder Analyzer from PS Prozesstechnik GmbH, Neuhausstrasse 36, CH-4057 Basel at 0.5 rpm and using a cylinder with an internal depth of 35 mm and an internal diameter of 100 mm; the frame rate was 10 images per second and 300 avalanches were recorded. The avalanche angle determined in this way was 68 degrees and the duration between two avalanches was 3.0 seconds. To the free-flowing impregnated particulate material, at room temperature, 999.9 mL of an aqueous hydrazine solution having a pH of 13.8 [2.80 g (88 mmol) of hydrazine and 54.66 g of a 32 wt % sodium hydroxide solution (437 mmol NaOH), remainder: water] were added at a metering rate of 30 mL/min with stirring. Over time, a black homogeneous pulp which became increasingly easy to stir was formed. After completion of the metered addition, stirring was continued for 30 minutes until no more nitrogen release could be observed. Subsequently, the material was strained off, washed with a total of 1000 mL of water and dried in a drying cabinet at 105° C./300 mbar to a residual moisture content of 15 wt %. By means of ICP-OES, a silver content of 10.88 wt % and a ruthenium content of 0.21 wt % of the end product (based on 0 wt % of residual moisture) were determined.

Exemplary Embodiment 3 (Production of a Cellulose Powder Provided With 18.9 wt % of Elemental Silver and 1.0 wt % of Elemental Ruthenium)

[0065] 75.6 g (445 mmol) of solid silver nitrate and 13.94 g of ruthenium nitrosylnitrate solution (ruthenium content 19.0 wt %; 26.2 mmol Ru) were dissolved in 416.8 g of demineralized water, and the aqueous precursor solution obtained in this way was mixed homogeneously with 211.2 g of cellulose powder (Vitacel® L-600 from J. Rettenmaier and Sohne GmbH & Co KG) to give an orange, free-flowing impregnated particulate material. 100 mL of this material were subjected to rotary powder analysis at 20° C. by means of the Revolution Powder Analyzer from PS Prozesstechnik GmbH, Neuhausstrasse 36, CH-4057 Basel at 0.5 rpm and using a cylinder with an internal depth of 35 mm and an internal diameter of 100 mm; the frame rate was 10 images per second and 300 avalanches were recorded. The avalanche angle determined in this way was 73 degrees and the duration between two avalanches was 3.5 seconds. To the free-flowing impregnated particulate material, at room temperature, 705 mL of an aqueous hydrazine solution having a pH of 13.9 [4.19 g (131 mmol) of hydrazine and 81.81 g of a 32 wt % sodium hydroxide solution (654.51 mmol NaOH), remainder: water] were added at a metering rate of 30 mL/min with stirring. Over time, a black homogeneous pulp which became increasingly easy to stir was formed. After completion of the metered addition, stirring was continued for minutes until no more nitrogen release could be observed. Subsequently, the material was strained off, washed with a total of 1000 mL of water and dried in a drying cabinet at 105° C./300 mbar to a residual moisture content of 15 wt %. By means of ICP-OES, a silver content of 18.9 wt % and a ruthenium content of 1.0 wt % of the end product (based on 0 wt % of residual moisture) were determined.