Coating comprises a particle layer made from a nano-particulate photocatalytically active material arranged on a primer layer made from porous inorganic or inorganic-organic material

The Invention relates to a coating.

On the field of coatings, it is known, primer layers, usually of silicon dioxide, apply where then plies or layers of photocatalytic oxides are deposited. deposition usually takes place by vacuum process, in individual cases, by titanium dioxide / silica sol-gel mixtures.

Out WO 97/23572 is a process for Hydrophilizing the surface a substrate known by photocatalysis. A substrate is with a photocatalytic TiO₂-Layer covered that on the surface a solid acid to increase bears the proportion of hydrogen bonds in the solid-liquid interface. at photoexcitation will increase the amount of hydrogen bonds and thus adsorption of water molecules from the atmosphere speeds of terminal TiOH groups and bridging OH groups. This forms a dense physically adsorbed water film, the hydrophilic character the promotes.

The WO 98/03607 discloses a composition for hydrophilizing of surface and Production of anti-fog properties, consisting of photocatalytic Particles of metal oxide, at least one component from the group particulate SiO₂, Precursors, the SiO₂films may form and solvents exist, the transparent after application and drying or heating Movies forms.

Out WO 99/41322 is a coating material to form a photocatalytic hydrophilic film is known which consists of an amorphous TiO₂-Precursor, Crystalline TiO₂ and a precursor to the formation of siloxane bonds is.

In WO 99/64364 describes a process for preparing a fiber-containing described substrate, whose surface at least partially with a photocatalytic and hydrophilic coating is provided, said photocatalytic semiconductor material oxide and sulfur-based, especially TiO₂Which at least partially crystallized in anatase form, by means of an adhesion promoter with the connected fiber material and the TiO₂ as introduced particles in colloidal suspension, or in powder form becomes.

Out of the <patcit><text>EP 1118385 A1</text></patcit> is a process for producing a photocatalytically active material by coating a substrate with a photocatalytically active Metal oxide and / or its precursor and a fast heating up of the Substrate to 100 to 600 ° C known.

The <patcit><text>EP 1074525 A1</text></patcit> concerns an article having photocatalytic activity, comprising a substrate, on which a primer layer of an n-type semiconductor is arranged, which, in turn, a photocatalytic layer of an n-type semiconductor having.

In WO 01/21722 is a photocatalytic, hydrophilic coating material is described based on surfaces is easy to apply and a having high degree of sustainable hydrophilicity and transparency. It contains Water, a photocatalytically active metal oxide, an alkyl silicate and an alkali silicate.

task of the invention is to provide a new coating with photocatalytic to create properties, is present in both the greatest possible photocatalytic activity guaranteed, but also optimum moisture exchange is.

in the this object the invention is achieved in that a Primer layer of porous inorganic or inorganic-organic material, a particle layer of at least one nanoparticulate photocatalytically active substance is applied, whereby individual in this particle layer particles having an average particle size of 2 to 150 nm at a distance between 1 and 50 nm from each other on the primer layer are arranged.

Of the Invention is based on the finding that the level of photocatalytic activity different influence parameters Has. Main factor is the surface and thus the exchange surface the active centers. disturbances type in particular by covering the photocatalytic Centers, for example by silanization caused.

furthermore are in addition to the UV-irradiation, a continuous film of moisture and oxygen for the macroscopic effects of the photocatalytic activity is indispensable.

It has surprisingly been found in the invention that by the inventive structure of the coating produces a substantially larger active surface is as in prior art coatings, which is due to the fact the existence Nanoparticles of approximately 15 nm in diameter between a surface 400 and 800 nm² having. The hydrophilic Primer layer acts because of their porosity as a reservoir for water and dissolved therein Oxygen and yet has a blocking effect on the pad, so that the coating of organic-based substrates such as plastics, Natural materials, leather, textiles or paper is possible. Due to the fact, that the par&lt;?page 3?&gt;tikelschicht is not tight, diffusion paths are present on the surface.

A preferred embodiment of the invention is that the Primer layer of silicon dioxide, zirconium oxide, aluminum oxide, thereof mixed oxides or organically modified compounds thereof consists.

It So come especially primer layers of the pure oxides (especially Silica), of mixed oxides thereof or organically modified Compounds based on the pure oxides or the mixed oxides (For example, silicon-organic compounds such as methyltriethoxysilane) in question.

It has proven to be advantageous that the primer layer has a porosity of less than 2 nm.

A Embodiment of the invention is that the primer layer has a layer thickness from 50 nm to 1 micron, preferably from 100 to 900 nm.

It is advantageous in that the Particle layer of ZnO, CaTiO₃, SnO₂, MoO₃, Fe₂O₃, WHERE₃. Nb₂O₅, SiC, Ti_xZr_1-xO₂. ZrO, TiO₂, In particular the anatase modification Tio₂, Or selenium salts, or mixtures thereof consists.

A Embodiment of the invention bestetht that the average particle size of the particles in the particle layer 5 to 50 nm, preferably 5 to 20 nm, is.

According to the invention, that the particles the particle layer to the primer layer by a partial silanization are connected.

in the Scope of the invention is also a method of applying a coating according to the invention on a substrate, wherein a coating of the invention onto a substrate applied and then cured becomes.

in this connection it is expedient that the primer layer is prepared by the sol-gel method.

furthermore it is according to the invention that the primer layer and the particle layer in each case, by spraying, pouring, flooding, dipping, rolling or skidding be applied to the substrate.

A Embodiment of the method is that the particle layer on the not yet cured Primer layer is applied.

at another embodiment of the method it is provided that the particle layer is applied to the pre-dried primer layer.

furthermore it is expedient that the pre-drying the primer layer thermally at temperatures between room temperature and 1200 ° C and / or carried out by jet drying.

A Development of the invention is that the curing of the coating thermally at Temperatures between room temperature and 800 ° C and / or jet drying takes place.

Under Jet drying means the drying by electron beam, UV-radiation, microwaves, etc.

Finally is a use of the coating according to the invention as a coating for plastics, Textiles, ceramics, leather, wood, metals or materials as part of the Invention.

Of the Construction of an inventive coating hereinafter reference to a drawing of an embodiment shown and described, and examples are given.

It shows

<figref idrefs="S13">1</figref> a schematic representation of a coating of the invention.

On the substrate, which is to surfaces made of plastics, textiles Ceramics, leather, wood, metals or coated with paints surfaces act can, is first a primer layer <figref>1</figref> of silica in the sol-gel process applied.

These primer layer <figref>1</figref> has no photocatalytic activity and serves to distinguish from the substrate and because of the hydrophilic Properties of siloxane network as a water reservoir. The porosity of the primer layer<figref>1</figref> lies In the &lt;2 nm, the Layer thickness of between 50 nm and 1 micron, with layer thicknesses between 100 and 900 nm are preferred.

On this primer layer <figref>1</figref> is a particle layer <figref>2</figref> applied, which is not a closed layer, but individual, spaced apart (spacing about 1 to 100 nm) particles with an average particle size of 2 to 150 nm, wherein a particle size of 5 to 50 nm, preferably and is 5 to 20 nm is particularly preferred. The particles consist of titanium dioxide, the anatase form because of their high photocatalytic activity is preferred. Due to the spacing of the particles and their Nanostructure is a maximum active surface of the photokataly&lt;?page 4?&gt;shows active reached particles. Water can diffuse through this layer to the surface, so that a achieved protection against deactivation of the water tank by the photoactivity of the nanoparticles becomes.

The Coating may be applied to many substrates, such as such as textiles, leather, paper, concrete, stone, plaster or painted surfaces. It is suitable for objects of all kinds, such as shoes, clothing, tarpaulins, billboards, devices (Eg sunblinds, window profiles (especially PVC), Conservatories, Glass domes, facade elements, roof tiles, shutters, fireplaces, door and Window handles), telephone cells, monuments, satellite systems, antennas, Bridges, buildings (in particular Skyscrapers) Flower pots, garden furniture, garden tools, garden gnomes, Bus stop shelters, Electricity Pylon, power boxes, Gutters, playground equipment, grave stones, billboards, posters, Kitchens and kitchen equipment, vehicles and vehicle parts (eg car mirror, automotive coatings, vehicle wheels, Vehicle wheels, bumpers, Truck tarpaulins, vehicle registration), traffic signs, traffic mirrors, Cycles, Motorcycles, Spacecraft, aircraft and aircraft parts, helicopters, satellites, Spacesuits, medical equipment, medical Facilities and sanitation, Swimming pools, Tents, solar systems and - cells, electrical and electronic components (eg wires, cables, lamps, lanterns, Measuring devices), optical lenses or machine parts.

Embodiment 1:

Primer solution:

To 208.3 g [1 mol] of tetraethoxysilane (TEOS) is 100 g of 0.1 molar HNO₃ was added and stirred for 12 h. The hydrolyzate is with 892 g of isopropanol diluted to a solids content of 5%.

Particle solution:

2g Titanium dioxide in the anatase modification (nano powder, particle size 10 nm) are dispersed in 98 g of acetyl acetone and stirred for 30 minutes. It ensteht a translucent dispersion having a solids content of 2% TiO₂,

On Substrate using the example of an aluminum plate of 100 × 100 × 3 mm with the primer solution sprayed and dried at room temperature for 24 h. Thereafter, the particle dispersion is a wet film thickness of 5 microns by spray coating misted and flashed off for 2 hours. During this time the particles are teilsilanisiert at the contact points, whereby the excellent adhesion is obtained. The photocatalytic Surface coverage is then for 2 h in a convection oven at 300 ° C compacted. The result is a visually opposite to the substrate material is not perceptible photocatalytic surface coverage with silanized highly active nanoparticles.

to Activation of the photocatalytic activity of the anatase, the substrate 5 days in the outdoor area (Sun position) stored.

The photocatalytic surface coverage has an extremely high abrasion resistance steel wool (50 strokes - no effect loss) high chemical resistance (2 hours 1% KOH - no Attack) and very good adhesion (cross-cut tape test very good) result.

After outdoor storage shows the photocatalytic sleeps a contact angle of 10 ° against water and anti-fog properties when breathed on. After 3 weeks of storage the photocatalytically occupied substrate together with an uncoated Substrate on a busy road you recognize clearly a substantially reduced soiling tendency of photocatalytic occupied Surface.

Embodiment 2:

Primer solution:

To 208.3 g [1 mol] of tetraethoxysilane (TEOS) is 100 g of 0.1 molar HNO₃ was added and stirred for 12 h. The hydrolyzate is with 22.2 DAMO (Fa. Degussa) was added and quickly with 1227 g of water a solids content of 5% diluted.

Particle solution:

2g Titanium dioxide in the anatase modification (nano powder, particle size 10 nm) are dispersed in 98 g of acetyl acetone and stirred for 30 minutes. It ensteht a translucent dispersion having a solids content of 2% TiO₂,

On Substrate using the example of a float glass plate of 100 × 100 × 3 mm sprayed with primer solution and 24 h dried at room temperature. Thereafter, the particle dispersion is a wet film thickness of 5 microns by spray coating misted and flashed off for 2 hours. The photocatalytic surface coverage thereafter for 2 h in a convection oven at 300 ° C compacted. A transparent, optically opposite the Substrate material imperceptible photocatalytic surface coverage with silanized highly active nanoparticles.

to Activation of the photocatalytic activity of the anatase, the substrate 5 days in the outdoor area (Sun position) stored.

The photocatalytic surface coverage &lt;?page 5?&gt;Has an extremely high abrasion resistance steel wool (50 strokes - no effect loss) high chemical resistance (2 hours 1% KOH - no Attack) and very good adhesion (cross-cut tape test very good) result.

After outdoor storage shows the photocatalytic sleeps a contact angle of 10 ° against water and anti-fog properties when breathed on. After 3 weeks of storage the photocatalytically occupied substrate together with an uncoated Substrate on a busy road you recognize clearly a substantially reduced soiling tendency of photocatalytic occupied Surface.

Embodiment 3:

Primer solution:

To 208.3 g [1 mol] of tetraethoxysilane (TEOS) is 100 g of 0.1 molar HNO₃ was added and stirred for 12 h. The hydrolyzate is with 27.8 g GLYMO (Fa. Degussa) and 1.79 g DAMO (Fa. Degussa) was added and diluted with 1200 g of ethanol at a solids content of 5%.

Particle solution:

2g Titanium dioxide in the anatase modification (nano powder, particle size 10 nm) are dispersed in 98 g of acetyl acetone and stirred for 30 minutes. It ensteht a translucent dispersion having a solids content of 2% TiO₂,

On Substrate using the example of a corona-treated plastic plate of 100 × 100 × 3 mm (polycarbonate MACROLON, Fa. Bayer) is sprayed with the primer solution and dried at 80 ° C for 1 h. Thereafter, the particle dispersion is misted with a wet film thickness of 5 microns by spray vented and 1 h. The photocatalytic surface coverage thereafter for 2 h in a convection oven at 130 ° C compacted. The result is not an optically opposite the substrate material perceptible photocatalytic surface occupation silanized highly active nanoparticles.

to Activation of the photocatalytic activity of the anatase, the substrate 5 days in the outdoor area (Sun position) stored.

The photocatalytic surface coverage has an extremely high abrasion resistance steel wool (50 strokes - no effect loss) high chemical resistance (2 hours 1% KOH - no Attack) and very good adhesion (cross-cut tape test very good) result.

After outdoor storage shows the photocatalytic sleeps a contact angle of 10 ° against water and anti-fog properties when breathed on. After 3 weeks of storage the photocatalytically occupied substrate together with an uncoated Substrate on a busy road you recognize clearly a substantially reduced soiling tendency of photocatalytic occupied Surface.

Embodiment 4:

Primer solution:

To 208.3 g [1 mol] of tetraethoxysilane (TEOS) is 100 g of 0.1 molar HNO₃ was added and stirred for 12 h. The hydrolyzate is with 30 g of silica 2005/30, 27.8 g GLYMO (Fa. Degussa) and 22.2 DAMO (. Degussa) was added and at 1418 g water / ethanol mixture (3: 1) diluted to a solids content of 5%.

Particle solution:

2g Titanium dioxide in the anatase modification (nano powder, particle size 10 nm) are dispersed in 98 g of acetyl acetone and stirred for 30 minutes. It ensteht a translucent dispersion having a solids content of 2% TiO₂,

On Substrate using the example of a corona-treated plastic plate of 100 × 100 × 3 mm (polycarbonate MACROLON, Fa. Bayer) is sprayed with the primer solution and dried at 80 ° C for 1 h. Thereafter, the particle dispersion is misted with a wet film thickness of 5 microns by spray vented and 1 h. The photocatalytic surface coverage thereafter for 2 h in a convection oven at 130 ° C compacted. The result is not an optically opposite the substrate material perceptible photocatalytic surface occupation silanized highly active nanoparticles.

to Activation of the photocatalytic activity of the anatase, the substrate 5 days in the outdoor area (Sun position) stored.

The photocatalytic surface coverage has high abrasion resistance against steel wool (50 strokes - no effect loss) high chemical resistance (2 hours 1% KOH - no Attack) and very good adhesion (cross-cut tape test very good) result.

After outdoor storage shows the photocatalytic sleeps a contact angle of 10 ° against water and anti-fog properties when breathed on. After 3 weeks of storage the photocatalytically occupied substrate together with an uncoated Substrate on a busy road you recognize clearly a substantially reduced soiling tendency of photocatalytic &lt;?page 6?&gt;occupied Surface.