WO2008148363A2

WO2008148363A2 - An agent for surface finishing of objects and strustures by a coating layer with a photocatalytic and self-cleaning effect and respective manufacturing process

Info

Publication number: WO2008148363A2
Application number: PCT/CZ2008/000062
Authority: WO
Inventors: Vaclav Stengl; Petr Ratajsky
Original assignee: ROKOSPOL AS; Institute of Inorganic Chemistry CAS
Current assignee: ROKOSPOL AS; Institute of Inorganic Chemistry CAS
Priority date: 2007-06-07
Filing date: 2008-06-06
Publication date: 2008-12-11
Anticipated expiration: 2009-12-07
Also published as: WO2008148363A3; CZ301227B6; CZ2007395A3

Abstract

An agent for surface finishing of objects and structures by a coating layer with a photocatalytic and self-cleaning effect, above all with the catalytic effects of air pollutants´ photodegradation. It is created by a precursor based on a dispersion of at least one compound from the group of metals´ oxids and salts in nanocristalline form, which is photoactive even in the visible band of the solar radiation spektrum. The precursor said being a hydrolysis product of respective metal´s soluble salt in the medium of silicates, silicic esters, siloxanes or silicon alcoxides.

Description

AN AGENT FOR SURFACE FINISHING OF OBJECTS AND STRUCTURES BY A COATING LAYER WITH A PHOTOCATALYTIC AND SELF- CLEANING EFFECT AND RESPECTIVE MANUFATURING PROCESS

The field of technology

This invention regards an agent for surface finishing of objects and structures by a coating layer with a photocatalytic and self-cleaning effect, above all with the catalytic effects of air pollutants' photodegradation as well as the process of this agent's manufacturing.

This field's actual state of things

Nowadays, many agents serving as paints and coating materials for structures (particularly for external buildings and structures) with effects of air pollutants' photodegradation are known.

As regards the bulding materials, there are known eg concrete mixtures containing (as an additive) the photocatalytic active titanium dioxide.

From the point of view of receptures for external buildings and structures, as advantageous appears particularly using of organo-metallic precursors containing particles of photocatalytic active compounds, above all of the titanium dioxide; regarding this, there is known usage of precursors which originated by homogenous hydrolysis of the soluble salts (chlorides) of titanium by urea or thioacetamide in aqueous medium. However, the precursors gained can only be used as the active component of respective paint, not as a paint itself. From this perspective, as more hopeful appears to be to use transparent layers based on polyvinylalcohol or hydroxyethylacrylate ie precursors which were created by hydrolysis of dilutable salts of titanium in presence of respevtive polymers; but even these ones themselves cannot provide the required mechanical and chemical resistance of the paint exposed to external influences.

Simultaneously, many ways how to prepare and use the transparent particles of metals are known. Such particles of metal oxids can be utilized in many fields eg as pigments in the paints industry, in cosmetics as a protective factor against the UV rays, preparing thin layers, etc. To prepare transparent titanium dioxide particles (or transparent layers), advantageously eg the controlled hydrolysis of titanium alcoxids is used. Another method is a plasmatic or magnetron coating of titanium dioxid in thin layers. These ways, however, are disadvantageous due to their complexity, labour-consumption and necessity to warm up the final product up to min 400 ⁰C.

Nature of the invention

This agent for surface finishing of objects and structures by a coating layer with a photocatalytic and self-cleaning effect as per invention is to a large extent instrumental in removing the aforementioned deficiencies of the status quo in this field.

This invention's nature insists in the fact that it consists of a precursor which iis based on a dispersion of at least one compound from the group of metals' oxids and salts in nanocristalline form, being visible even in the visible band of the solar radiation spectrum; the precursor said is a hydrolysis product of respective metal's soluble salt in the medium of silicates, silicic esters, siloxanes or silicon alcoxides.

As to the photoactive compound which is present in the precursor said as transparent particles, this can be above all the titanium oxide, ferric oxide or zirconium dioxide.

This metal oxide can be further supported by transient metals Oxides, particularly of Fe, Co, Ni, Mn, Cr, V, Ta, Nb and W, and/or lanthanoide oxides, particularly of La, Ce, Nd, Y, Sm, Eu and Dy.

The agent for surface finishing of objects and structures as per invention is at the same time a precursor and a paint with final qualities gained after spontaneous curing.

The way how to manufacture this agent for surface finishing of objects and structures as per invention insists in a hydroysis of respective metal's soluble salts under lab or elevated temperature (advantageously up to 150 °C) in the medium of silicates, silicic esters, siloxanes or silicon alcoxides.

As to the soluble metal salt, this can be advantageously the titanium(III) chloride, titanium dichloride or titanium oxide chloride.

By the aforementioned way, a new composite material can be created which is applicable onto any surface type, with final qualities after spontaneous curing. It is strong, perfectly washable, with a self-cleaning or photocatalytic effect due to presence of metal ocide nanoparticles (above all the titanium oxide ones), and-due to chosen combination of various anorganic polymeres-is also suitable for anti-graffiti systems, being also usable as a precursor in the production of more sofisticated paints with other binding systems. This agent can be applicated by brushing, spraying or rolling when (after a sufficient dilution) also thin transparent layers can be obtained. The surfaces coated in this way have the advantage thet they gain (as against existing transparent paint films), after being illuminated, a highly wettable surface, and due to the photocatalytic effect the organic inpurities or air pollutants adhering to this surface shall be decomposed.

Examples of this invention's practical execution

Example 1

To 100 ml cone, hydrochlorid acid dissolve 1Og metallic titanium and add to the total volume 100 ml the distilled water (hereinafter referred to as Solution 1). To 100 ml tetraethylorthosilicate (TEOS) add 50 ml of the Solution 1. After mixing, the reagent solution goes blue-violet. The solution is to be intensively stirred under the lab temperature. As it is decolourized, stop stirring. The final product is a clear opalescent liquid containing transparent TiO₂ particles.

Example 2

To 100 ml tetramethoxisilane (TMOS) add 20 ml of the 10% TiC14 in HCl. After mixing together, the reagent solution remains clear. The solution is to be intensively stirred under the lab temperature. Created transparent articles are checked by the laser ray passage. The final product is a clear opalescent liquid containing transparent TiO₂ particles.

Example 3

To 100 ml methyltriethoxisilane (MTEOS) add 10 ml TiOCl. After mixing together, the reagent solution remains clear. The solution has to be intensively stirred under the lab temperature. Created transparent articles are checked by the laser ray passage. The final product is a clear opalescent liquid containing transparent TiO₂ particles.

Example 4

To 100 ml vinyltriethoxisilane (VTEOS) add 50 ml of the Solution 1. After mixing, the reagent solution goes blue-violet. The solution is to be intensively stirred under the lab temperature. As it is decolourized, stop stirring. The final product is a clear opalescent liquid containing transparent TiO₂ particles.

Example 5

To 100 ml of the Solution 1 add a 10% tetraethoxisilane solution in ethanol and methoxypropylacetate with 0.7% siloxane in the 800 ml volume. After mixing, the reagent solution goes blue- violet. The solution is to be intensively stirred under the lab temperature. As it is decolourized, stop stirring. The final product is a clear opalescent liquid containing transparent TiO₂ particles.

Example 6

To 100 ml of a 20% tetraethoxisilane solution add 300 ml ethanol and 50 ml of a 15% Solution 1. The reagent solution is to be intensively stirred under the lab temperature. As it is decolourized, stop stirring. The final product is a clear opalescent liquid containing transparent TiO₂ particles.

Example 7

To 100 ml of a 20% tetraethoxisilane solution add 2,5 g 3-(polyoxyethylene) propylheptamethyl trisiloxane in 300 ml ethanol and 100 ml of a 15% TiCl₃ in HCl (Sigma -Aldrich). The reagent solution was intensively stirred under the lab temperature till decolourizing.

Example 8

To 100 ml of a 10% TiCl₄ solution v HCl add 10% of a tetraethoxisilane solution in ethanol and methoxypropylacetate with 0.7 % siloxane in the 800 ml volume. The reagent solution has to be intensively stirred under the lab temperature. Created transparent articles are checked by the laser ray passage. The final product is a clear opalescent liquid containing transparent TiO₂ particles.

Example 9

To 100 ml of a 10% TiOCl solution in HCl add 10% of a tetraethoxisilane solution m ethanol and methoxypropylacetate with 0.7 % siloxane in the 800 ml volume. The reagent solution has to be intensively stirred under the lab temperature. Created transparent articles are checked by the laser ray passage. The final product is a clear opalescent liquid containing transparent TiO₂ particles.

Example 10

To 100 ml of a 10% ferric chloride solution add a 5-10% of a tetraethoxisilane solution in ethanol and methoxypropylacetate with 0.7 % siloxane in the 800 ml volume; then discolouring begins, going (from the original rusty brown) clear.

Claims

P A T E N T C L A I M S

1. An agent for surface finishing of objects and structures by a coating layer with a photocatalytic and self-cleaning effect, above all with the catalytic effects of air pollutants' photodegradation, comprising the fact that it is created by a precursor based on a dispersion of at least one compound from the group of metals' oxids and salts in nanocristalline form, which is photoactive even in the visible band of the solar radiation spectrum the precursor said being a hydrolysis product of respective metal's soluble salt in the medium of silicates, silicic esters, siloxanes or silicon alcoxides.

2. An agent as per Claim 1, comprising the titanium dioxide as the photoactive compound present in the precursor in the form of transparent particles.

3. An agent as per Claim 1, comprising the ferric oxide as the photoactive compound present in the precursor in the form of transparent particles.

4. An agent as per Claim 1, comprising the zirconium dioxide as the photoactive compound present in the precursor in the form of transparent particles.

5. An agent as per Claims 2 through 4, comprising as the photoactive compound present in the precursor in the form of transparent particles the respective metal oxide which is supported by transient metals'oxides, particularly of Fe, Co, Ni, Mn, Cr, V, Ta, Nb, W, and/or lanthanoide oxides, particularly of La, Ce, Nd, Y, Sm, Eu, Dy.

6. A method of production of the agent for surface finishing of objects and structures as per Claim 1, comprising a hydrolysis of respective metal salt solution under the lab or elevated temperature in the medium of silicates, silicic esters, siloxanes and silicon alcoxides.

7. A method as per Claim 6, comprising carrying out the hydrolysis under the temperature up to 150 ⁰C.

8. A method as per Claim 6, comprising as the parent soluble salt of metal the titanium(III) chloride, titanium dichloride or titanium oxide chloride.