Antimicrobial quaternary ammonium organosilane compositions

1. Antimicrobial granules comprising carrier particles agglomerated by a binding agent containing a quaternary ammonium organosilane.

2. Antimicrobial granules according to claim 1 wherein the carrier particles are selected from silica, silicate, aluminosilicate, carbonate, sulfate and oxide particles.

3. Antimicrobial granules according to claim 2 wherein the carrier particles are zeolite particles.

4. Antimicrobial granules according to claim 1 wherein the mean particle size of the carrier particles is in the range 1 to 10 μm.

5. Antimicrobial granules according to claim 1 wherein the mean particle size of the granules is in the range 0.1 to 2.0 mm.

6. Antimicrobial granules according to claim 1 wherein the binding agent is a water-soluble or water-dispersible polymer selected from polyvinyl alcohols, methyl cellulose, carboxy methyl cellulose, polycarboxylates, and cationic polymers.

7. Antimicrobial granules according to claim 1 wherein the binding agent is an emulsifiable water-insoluble polymer selected from polyvinyl acetate, vinyl acetate ethylene copolymers and acrylate ester polymers.

8. Antimicrobial granules according to claim 1 wherein the quaternary ammonium organosilane is of the formula

where each R represents a methyl or ethyl group; a is 0, 1 or 2; R′ if present represents a methyl or ethyl group; Z represents an alkylene group having 3 or 4 carbon atoms; R 2 represents a methyl or ethyl group; R 3 represents an alkyl group having 8 to 18 carbon atoms or an aralkyl group; R 4 represents an alkyl or hydroxyalkyl group having 1 to 18 carbon atoms; and X represents an anion selected from chloride, bromide, fluoride, iodide, an arylsulphonate anion and acetate.

9. Antimicrobial granules according to claim 1 wherein the quaternary ammonium organosilane content of the granules is in the range 0.5 to 30% by weight.

10. Antimicrobial granules according to claim 1 wherein the binding agent further contains an organosilane or organopolysiloxane having no amine or quaternary ammonium functionality.

11. Antimicrobial granules according to claim 10 wherein the organosilane having no amine or quaternary ammonium functionality is a hydrophobic alkylalkoxysilane containing an alkyl group having at least 3 carbon atoms.

12. A process for the preparation of antimicrobial granules comprising applying a liquid binding medium containing a dispersed quaternary ammonium organosilane to carrier particles and solidifying the carrier particles to which the liquid binding medium has been applied to agglomerate the carrier particles into granules.

13. A process for the preparation of antimicrobial granules comprising simultaneously applying a liquid containing a dispersed quaternary ammonium organosilane and a liquid binding medium to carrier particles and drying the carrier particles to which the liquid binding medium has been applied to agglomerate the carrier particles into granules.

14. A process according to claim 12 wherein the liquid binding medium is an aqueous solution of a binding agent.

15. A process according to claim 14 wherein the binding agent is polyvinyl alcohol.

16. A process according to claim 12 wherein the quaternary ammonium organosilane is emulsified in the solution of binding agent.

17. A process according to claim 12 wherein the process further comprises spraying the liquid binding medium containing dispersed quaternary ammonium organosilane onto the carrier particles.

18. A process according to claim 12 wherein the drying of the carrier particles to which the liquid binding medium containing the dispersed quaternary ammonium organosilane has been applied is carried out in a fluidized bed.

19. A cementitious or gypsum building material comprising cement or gypsum and antimicrobial granules according to claim 1 .