Surface-Doped Particles Of Ti02 Or Zno And Their Use

• US 20080031832A1
• Filed: 01/26/2005
• Published: 02/07/2008
• Est. Priority Date: 01/28/2004
• Status: Abandoned Application

• Current Assignee: Oxonica Limited
• Original Assignee: Oxonica Limited
• Inventors: Lipscomb, Sarah, Park, George Barry, Holland, Edward, Wakefield, Gareth
• Application Number:
  US10/588,071
• Publication Number:
  US 20080031832A1
• Time in Patent Office: Days
• US Class Current: 424/59
• CPC Class Codes: A01N 25/22 containing ingredients stabilising the active ingredients
• CPC Class Codes: C01G 23/00 Compounds of titanium preparation of Ti-compounds from ores or scraps C22B34/12
• CPC Class Codes: C01G 9/00 Compounds of zinc
• CPC Class Codes: C09C 1/043 Zinc oxide
• CPC Class Codes: C09C 1/3653 Treatment with inorganic compounds
• CPC Class Codes: C09C 1/3661 Coating
• CPC Class Codes: C09C 1/3692 Combinations of treatments provided for in groups C09C1/3615 - C09C1/3684

Abstract

A particle of TiO₂ or ZnO which has been doped with one or more other elements such that the concentration of dopant in the surface of the particle is greater than that at the core of the particle, and compositions containing such particles for use as sunscreens or in veterinary, agricultural or horticultural compositions or as coatings for plastics and other materials.

Claims

1. A particle of TiO₂ or ZnO which has been doped with one or more other elements such that the concentration of dopant in a surface of the particle is greater than that at a core of the particle.

2. A particle according to claim 1 which is coated with a discontinuous layer of hydrophilic or hydrophobic material.

3. A particle according to claim 2 which is coated with hydrophobic polymer.

4. A particle according to claim 2 which is coated first with an oxide of aluminium, zirconium or silicon and then with a long chain carboxylic acid salt.

5. A process for preparing a particle as claimed in claim 1 which comprises placing a particle of TiO₂ or ZnO in contact with a solution or suspension of a salt of the dopant for a time insufficient for the concentration of dopant salt in the core of the particle to reach that at its surface and then baking the resulting particle.

6. A process according to claim 5 wherein the particle is baked at a temperature of at least 500°

C.

7. A particle according to claim 1 that is prepared by placing a particle of TiO₂ or ZnO in contact with a solution or suspension of a salt of the dopant for a time insufficient for the concentration of dopant salt in the core of the particle to reach that at its surface and then baking the resulting particle.

21. A method for reducing the concentration of one or more organic UV sunscreen agents or other ingredient which is photosensitive and/or is degraded by another ingredient in a UV sunscreen composition comprising incorporating into the composition a doped TiO₂/ZnO as defined in claim 1 to reduce the concentration of one or more organic UV sunscreen agents or other ingredient which is photosensitive and/or is degraded by another ingredient in the UV sunscreen composition.

22. A process for increasing the effectiveness of an organic UV sunscreen composition which comprises one or more components which are photosensitive and/or are susceptible to degradation by another ingredient of the composition and/or by undoped TiO₂ and/or by undoped ZnO, which process comprises incorporating into the composition a doped TiO₂/ZnO as defined in claim 1.

23. A process for reducing the production of a toxic compound in a UV sunscreen composition which process comprises incorporating therein doped TiO₂ and/or ZnO as defined in claim 1.

38. A method for reducing the concentration of one or more light stabilisers in a polymeric composition comprising incorporating into the composition a surface doped TiO₂/ZnO as defined in claim 1 to reduce the concentration of one or more light stabilisers in the polymeric composition.

39. A method for reducing the rate of deterioration of a light-sensitive physical factor in a polymeric composition comprising incorporating into the composition a surface doped TiO₂/ZnO as defined in claim 1 to reduce the rate of deterioration of a light-sensitive physical factor in the polymeric composition.

40. A process for improving stability of a physical factor of a polymeric composition, which comprises one or more components which are photosensitive and/or are degraded by another ingredient of the composition which process comprises incorporating into the composition a surface doped TiO₂/ZnO as defined in claim 1.

44. A particle according to claim 1 wherein the dopant is manganese, selenium, cerium, chromium, vanadium or iron.

45. A particle according to claim 1 wherein the dopant is Mn²⁺ or other manganese, or is V⁴⁺.

46. A particle according to claim 1 wherein the dopant is present in an amount from 0.05% to 10 mole %.

47. A particle according to claim 46 wherein the dopant is present in an amount from 0.5 to 2 mole % by weight.

48. A particle according to claim 1 in which the doped oxide is doped titanium dioxide.

49. A particle according to claim 1 wherein the titanium dioxide is in rutile form.

52. A particle according to claim 1 wherein the doped or reduced oxide has a particle size from 1 to 200 nm, preferably 1 to 100 nm;

or from 100 to 500 nm.

56. A method for reducing the concentration of one or more veterinarally, agriculturally and/or horticulturally active compounds in a composition suitable for veterinary, agricultural, horticultural or household use comprising incorporating into the composition a surface doped TiO₂/ZnO as defined in claim 1 to reduce the concentration of one or more veterinarally, agriculturally and/or horticulturally active compounds in the composition suitable for veterinary, agricultural, horticultural or household use.

57. A method for increasing the shelf life of one or more veterinarally, agriculturally and/or horticulturally active compounds in a composition suitable for veterinary, agricultural, horticultural or household use comprising incorporating into the composition a surface doped TiO₂/ZnO as defined in claim 1 to increase the shelf life of one or more veterinarally, agriculturally and/or horticulturally active compounds in the composition suitable for veterinary, agricultural, horticultural or household use.

58. A process for increasing the effectiveness of a composition suitable for veterinary, agricultural, horticultural or household use which process comprises one or more organic veterinarally, agriculturally or horticulturally or household active compounds, which comprises incorporating into the composition a surface doped TiO₂/ZnO as defined in claim 1.

60. A particle according to claim 1 in which the mole ratio of dopant to host metal at the surface is 2-25 to 98-75.

61. A particle according to claim 60, in which the mole ratio of dopant to host metal at the surface is 8-75 to 92-25.

62. A particle according to claim 1 in which the concentration of dopant in a surface of the particle is greater than in the bulk of the particle.

63. A particle according to claim 1 in which there is no dopant at the core of the particle and/or in the bulk of the particle.

64. A particle according to claim 1 in which a dopant is present in the bulk of the particles, and wherein the bulk dopant is different from the or each surface dopant.

8. A UV sunscreen composition suitable for cosmetic or topical pharmaceutical use which comprises:

(a) one ore more organic components which are photosensitive and/or which are susceptible to degradation by another ingredient of the composition and/or by undoped TiO₂ and/or by undoped ZnO; and

(b) TiO₂ and/or ZnO which has been surface doped with one or more other elements.

9. A composition according to claim 8 which is an aqueous formulation and the TiO₂ and/or ZnO is only surface doped.

10. A composition according to claim 8 which is an oily formulation.

11. A composition according to claim 8 which is an oil-in-water or water-in-oil formulation.

12. A composition according to claim 11 wherein the TiO₂ and/or ZnO is present in both phases.

13. A composition according to claim 8 wherein the TiO₂ and/or ZnO is coated with a discontinuous layer of hydrophilic or hydrophobic material.

14. A composition according to claim 13 wherein the TiO₂ and/or ZnO is coated with a hydrophobic polymer.

15. A composition according to claim 13 wherein the TiO₂ and/or ZnO is coated first with an oxide of aluminium, zirconium or silicon and then with a long chain carboxylic acid salt.

16. A composition according to claim 8 wherein one or more of the said organic components is a UV sunscreen agent.

17. A composition according to claim 16 wherein the organic sunscreen agent absorbs UV light in the UVA region.

18. A composition according to claim 16 wherein the organic sunscreen agent is a paraaminobenzoic acid, ester or derivative thereof, a methoxy cinnamate ester, a benzophenone, a dibenzoylmethane, an alkyl-p-p-phenyl acrylate, a triazine, a camphor derivative, an organic pigment, a silicone based sunscreen agent or 2-phenylbenzimidazoyl-5 sulphonic acid or phenyldibenzimidazoyl sulphonic acid.

19. A composition according to claim 8 which contains one or more of a fatty substance, organic solvent, silicone, thickener, demulsant, UVB sunscreen agent, antifoaming agent, moisturising agent, perfume preservative, surface activation filler, sequestrant, anionic, cationic, nonionic or amphoteric polymer, propellant, alkalising or acidifying agent, colourant or metal oxide pigment.

20. A composition according to claim 8 which is a sunscreen.

28. A composition according to claim 8 which contains TiO₂ and/or ZnO which has not been doped, optionally as TiO₂ and/or ZnO particles which have not been doped.

29. A composition according to claim 28, wherein the said TiO₂ and/or ZnO is present as pigment.

30. A composition according to claim 8 in the form of a coating on and/or an additive in a polymeric material, which material is thermoplastic, or thermosetting or photosensitive.

31. A composition according to claim 8 which is in the form of a three dimensional article, or is in the form of a film, or is in the form of a photographic film, or is in the form of a coating composition, or is in the form of a paint or varnish.

50. A composition according to claim 8 which contains reduced zinc oxide.

51. A composition according to claim 8 which comprises 0.5 to 20 mole % by weight of the doped titanium dioxide and/or zinc oxide.

54. A composition according to claim 8 which contains one or more of a filler, organic solvent or surfactant.

55. A composition according to claim 8 which is in the form of an aqueous or non-aqueous liquid, a powder, granules or tablet.

24. A composition which comprises an amount of one or more organic or inorganic components which are photosensitive and/or which are degraded by another ingredient of the composition and an amount of TiO₂ and/or ZnO which has been doped at least on or in a surface thereof with one or more other elements.

25. A composition according to claim 24 which has a rate of deterioration of a UV light-sensitive physical factor at least 5% less than that of a composition having the same formulation except that it does not contain the said TiO₂ and/or ZnO which has been doped with a second element.

26. A composition according to claim 25 wherein the physical factor is tensile strength.

27. A composition according to claim 25 wherein the physical factor is colour.

32. A self-supporting polymeric composition intended to protect a composition adjacent thereto from the adverse effects of light which comprises TiO₂ and/or ZnO which has been doped at least in or on a surface thereof with one or more other elements or reduced ZnO.

33. A composition according to claim 32 wherein the TiO₂ and/or ZnO is present in a surface layer.

34. A composition according to claim 33 wherein a non-surface layer thereof is not wood.

35. A composition according to claim 33 wherein a non-surface layer thereof is synthetic.

37. A composition according to claim 32 which has a rate of deterioration of a UV light-sensitive physical factor at least 5% less than that of a composition having the same formulation except that it does not contain the said TiO₂ and/or ZnO which has been doped with a second element.

36. A varnish composition which comprises TiO₂ and/or ZnO which has been doped at least in or on a surface thereof with one or more other elements or reduced ZnO.

41. A composition suitable for veterinary, agricultural or horticultural use which comprises at least one organic veterinarally, agriculturally and/or horticulturally active compound, and titanium dioxide and/or zinc oxide which has been doped at least in or on a surface thereof with one or more other elements.

42. A composition according to claim 41 wherein the active compound is a herbicide, fungicide, insecticide, acaricide, miticide or rodenticide.

53. A composition according to claim 42 wherein the active compound is an insecticide.

59. A process for treating an agricultural or horticultural species at a locus which process comprises treating the locus with a composition as claimed in claim 41.

43. A composition suitable for household use which comprises at least one organic biocide, and titanium dioxide and/or zinc oxide which has been doped at least in or on a surface thereof with one or more other elements.

65. (canceled)