Photocatalytic composition and method for preventing algae growth on building materials

• US 6,881,701 B2
• Filed: 04/15/2003
• Issued: 04/19/2005
• Est. Priority Date: 03/21/2000
• Status: Expired due to Term

• Current Assignee: 3M Innovative Properties Company (3M Company)
• Original Assignee: 3M Innovative Properties Company (3M Company)
• Inventors: Jacobs, Jeffry L.
• Primary Examiner(s): Bell, Mark L.
• Assistant Examiner(s): Hailey, Patricia L.
• Application Number:
  US10/413,683
• Publication Number:
  US 20030190431A1
• Time in Patent Office: 735 Days
• Field of Search: 106/600, 106/623, 106/632, 106/635, 106/636, 1062861-2868, 502/80, 502/240, 502242-249, 502254-255, 502258-259, 502/261, 502/300
• US Class Current: 502/300
• CPC Class Codes: C04B 2111/00586 Roofing materials
• CPC Class Codes: C04B 2111/2061 Materials containing photocatalysts, e.g. TiO2, for avoiding staining by air pollutants or the like
• CPC Class Codes: C04B 41/5041 Titanium oxide or titanates
• CPC Class Codes: C04B 41/5089 Silica sols, alkyl, ammonium or alkali metal silicate cements
• CPC Class Codes: E04D 13/002 Provisions for preventing vegetational growth, e.g. fungi, algae or moss
• CPC Class Codes: E04D 7/005 characterised by loose or embedded gravel or granules as an outer protection of the roof covering
• CPC Class Codes: Y10T 428/2438 Coated
• CPC Class Codes: Y10T 428/24421 Silicon containing
• CPC Class Codes: Y10T 428/256 Heavy metal or aluminum or compound thereof
• CPC Class Codes: Y10T 428/258 Alkali metal or alkaline earth metal or compound thereof
• CPC Class Codes: Y10T 428/259 Silicic material
• CPC Class Codes: Y10T 428/2991 Coated

Abstract

The present invention provides a coating composition for substrates. The coating composition of the present invention generally includes a silicate binder and a plurality of photocatalytic particles. The silicate binder functions as a bonding agent to establish the coating on the substrate. A plurality of photocatalyst particles are dispersed throughout the silicate binder. The particles are included in an amount that provides sufficient distribution of the particles in the resulting coating. The incorporation of the present invention onto substrates prevents algal growth on building materials utilizing the coated substrates.

Claims

1. A coating composition comprising:

a plurality of photocatalytic particles and an alkali metal silicate binder, wherein the alkali metal silicate binder further comprises an aluminosilicate compound.

2. The coating composition of claim 1, wherein said photocatalytic particles comprise a material selected from TiO₂, ZnO, WO₃, SnO₂, CaTiO₃, Fe₂O₃, MoO₃, Nb₂O₅, Ti_xZr₍₁₋

x)O₂, SiC, SrTiO₃, CdS, GaP, InP, GaAs, BaTiO₃, KNbO₃, Ta₂O₅, Bi₂O₃, NiO, Cu₂O, SiO₂, MoS₂, InPb, RuO₂, CeO₂, Ti(OH)₄ or combinations thereof.

3. The coating composition of claim 1, wherein said photocatalytic particles have a mean particle size in the range of about 1 nm to about 1000 nm.

4. The coating composition of claim 1, wherein said composition further includes colored pigments.

5. The coating composition of claim 1, wherein the photocatalytic particles are provided in an amont effective to suppress or prevent algae growth.

6. The coating composition of claim 1 wherein the aluminosilicate compound is a clay.

7. The coating composition of claim 6 wherein the clay is kaolin.