Photocatalytically-active, self-cleaning aqueous coating compositions and methods

Abstract

Method for producing novel photochemically-active metal oxide-containing aqueous compositions such as TiO2 compositions coated or sprayed and dried under ambient conditions to form novel photochemically-active, colorless coatings having strong wetability and adhesion to clear substrates such as window glass. Preferably the present compositions include a suitable wetting agent or combination of agents to improve the wetability of the Titanium peroxide-containing amorphous film, allowing thinner films to be readily applied. Also the inclusion of an acrylic aliphatic urethane polymer can replace wholly or partially the titanium peroxide sol and provide additional film forming and wetability properties. The acrylic urethane polymer reduces or eliminates the amount of titanyl peroxide that is required and thereby reduces or eliminates the yellow color.

Description

technical field [0001] The present invention relates to photocatalytically active (PCA) coating compositions comprising photocatalytically active transition metal oxides (MO) or (MO 2 ), such as titanium dioxide (TiO 2 ) or zirconia (ZrO 2 ) catalysts for the production of transparent self-cleaning coatings, for example coatings for glass windows, which, under the action of exposure to sunlight, in particular ultraviolet radiation contained therein, react with the deposited thereon from the environment The organic compounds or pollutants react and cause them to break down. The organic pollutants are broken down into simple inorganic compounds such as CO 2 、H 2 O and various inorganic acids, which re-enter the atmosphere and / or are washed away by heat, wind and / or rain, so the coating is self-cleaning, the effectiveness of which depends on the MO 2 The level of photocatalytic activity of the catalyst, which is proportional to the MO to which the pollutant is exposed 2 The...

AI Technical Summary

Problems solved by technology

The time and labor involved in this application makes the use of the product impractical

[0011] 2. The film formation is difficult and the color is yellowish due to the presence of residual and unreacted titanyl peroxide

[0012] 3. When applied to glass, the transparency and transparency of the coating is impaired because excessive thickness is required to overcome the non-wetting properties of the substrate

However, TiO 2 The solubility is related to the addition of peroxide; without peroxide, TiO 2 insoluble