EP0913447A1

Photocatalytic hydrophilic coating composition

Abstract

A composition is disclosed which can hydrophilify the surface of a member to impart an antifogging property to the surface of the member. The composition for hydrophilifying the surface of the member comprises at least (a) photocatalytic particles of a metallic oxide, (b) a precursor capable of forming a silicone resin film or a precursor capable of forming a silica film, and (c) a solvent, the total content of the photocatalytic particle and the solid matter of the precursor in the composition being 0.01 to 5% by weight. The hydrophilic property can be imparted simply by applying the composition onto a member and drying or heating the composition applied to the member. The resultant hydrophilic thin film is transparent and, hence, does not sacrifice the transparency and appearance of a member required to be transparent. Further, the surface of a member with the above composition applied thereto has such a property that water droplets adhered thereon can be immediately removed by vaporization and the surface is less likely to be soiled and, even when a contaminant is adhered thereon, can easily release the contaminant therefrom.

EP0913447A1, drawing sheet 1
Sheet 1 of 8

Term

Term ended

Projected expiry passed 16 July 2017, 9.2 years ago.

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30 claims: 1 independent, 29 dependent

  1. 1
    A composition for hydrophilifying the surface of the member, comprising at least (a) photocatalytic particles of a metallic oxide, (b) at least one selected from a group consisting of silica fine particles, a precursor capable of forming a silicone resin film and a precursor capable of forming a silica film, and (c) a solvent, wherein the total content of the photocatalytic particle and the silica fine particles or the weight, in terms of silica, of the precursor in the composition is 0.01 to 5% by weight.
  2. 4
    The composition according to any one of claims 1 to 3, wherein the average crystallite diameter of the photocatalytic particles is 100 nm.
  3. 5
    The composition according to any one of claims 1 to 4, wherein the photocatalytic particles are constituted by the anatase form of titanium oxide.
  4. 6
    The composition according to any one of claims 1 to 5, which further comprises a material having a refractive index of not more than 2.
  5. 7
    The composition according to any one of claims 1 to 6, wherein the solvent is an alcohol.
  6. 10
    The composition according to any one of claims 1 to 9, which further comprises a surfactant.
  7. 13
    The composition according to any one of claims 1 to 12, which further comprises an acid.
  8. 14
    The composition according to any one of claims 1 to 13, wherein the composition comprises the silica fine particles and the average particle diameter of the silica fine particles is in the range of 1 to 100 mm.
  9. 15
    The composition according to any one of claims 1 to 13, wherein the composition comprises the silica fine particles and the average particle diameter of the silica fine particles is in the range of 5 to 50 mm.
  10. 16
    The composition according to any one of claims 1 to 13, wherein the composition comprises the silica fine particles and the average particle diameter of the silica fine particles is in the range of 8 to 20 mm.
  11. 17
    The composition according to any one of claims 1 to 13, wherein the precursor of a silica film is a silicate represented by the following average composition formula:SiX q O (4-q)/2 wherein X represents an alkoxy group or a halogen atom and q is a number satisfying 0 < q < 4.
  12. 18
    The composition according to any one of claims 1 to 13, wherein the precursor of a silica film is a tetrafunctional, hydrolyzable silane derivative represented by the general formula:SiX 4 wherein X represents an alkoxy group or a halogen atom.
  13. 19
    The composition according to any one of claims 1 to 13, wherein the precursor of a silicone resin film is a siloxane represented by the average composition formula:R p SiX q O (4-p-q)/2 wherein R represents a member selected from the group consisting of a hydrogen atom and one or more organic groups;X represents an alkoxy group or a halogen atom;and p is a number satisfying 0 < p < 2 and q is a number satisfying 0 < q < 4.
  14. 20
    The composition according to any one of claims 1 to 13, wherein the precursor of a silicone resin film is a hydrolyzable silane derivative represented by the general formula:R p SiX 4-p wherein R represents a member selected from the group consisting of a hydrogen atom and one or more organic groups;X represents an alkoxy group or a halogen atom;and p is 1 or 2.
  15. 21
    The composition according to any one of claims 1 to 20, which further comprises an antibacterial metal or a compound thereof.
  16. 22
    The composition according to any one of claims 1 to 21, which further comprises at least one metal selected from the group consisting of platinum, palladium, rhodium, ruthenium, osmium, and iridium.
  17. 23
    The composition according to any one of claims 1 to 22, wherein the photocatalytic oxide is selected from the group consisting of anatase form of titanium oxide, rutile form of titanium oxide, zinc oxide, tin oxide, ferric oxide, dibismuth trioxide, tungsten trioxide, and strontium titanate.
  18. 24
    The composition according to any one of claims 1 to 23, which, when applied to the surface of a member, imparts an antifogging property to the surface of the member.
  19. 25
    The composition according to any one of claims 1 to 23, which, when applied to the surface of a member to form a film, permits condensed water of moisture and/or water droplets adhered onto the surface to be spread on the film, thereby enabling the film to prevent the surface from being fogged or clouded by the condensed water of moisture and/or the water droplets.
  20. 26
    The composition according to any one of claims 1 to 23, which, when applied to the surface of a member to form a film, enables a contaminant adhered onto the surface to be easily washed away by water.
  21. 27
    An aerosol composition comprising the composition according to any one of claims 1 to 26, and a propellant.
  22. 28
    A method for hydrophilifying the surface of a member, comprising the steps of:applying the composition according to any one of claims 1 to 26 onto the surface of a member;and drying or curing the composition.
Independent claims22