Base with photocatalytic coating based on titanium dioxide and organ ic dispersion based on titanium dioxide
Abstract
PCT No. PCT/FR96/01419 Sec. 371 Date Mar. 12, 1998 Sec. 102(e) Date Mar. 12, 1998 PCT Filed Sep. 13, 1996 PCT Pub. No. WO97/10185 PCT Pub. Date Mar. 20, 1997The invention relates to a substrate provided, on at least a portion of one of its faces, with a coating with a photocatalytic property based on titanium dioxide which is at least partially crystalline and which is incorporated in the said coating partly in the form of particles predominantly crystallized in the anatase form. The invention also relates to a process for the preparation of this substrate and organic dispersions of titanium dioxide particles used in the said process for the preparation of the substrate.

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37 claims: 14 independent, 23 dependent
- 1NÁROKY 1. Podklad (1) opatřeny na alespoň jednom z jeho povrchů povlakem (3), majícím fotokatalytické vlastnosti, na bázi oxidu titaničitého, který je alespoň částečně krystalický a který je zabudován v uvedeném povlaku částečně ve formě částic převážně vykrystalizovaných v anatasové formě, přičemž uvedené částice jsou zabudované v povlaku (3) pomocí pojivá.
- 2Podklad (1) podle nároku 1,vyznačený tím, že částice mají velikost 5 až 80 nm.
- 3Podklad (1) podle nároku 1 nebo 2, vyznačený tím, že pojivém je anorganické pojivo, které je zejména ve formě amorfního nebo částečně krystalického oxidu nebo směsi oxidů z množiny zahrnující oxid křemičitý, oxid titaničitý, oxid ciničitý, oxid zirkoničitý a oxid hlinitý.
- 4Podklad (1) podle nároku 3,vyznačený tím, že povlak (3) má index lomu 1,40 až 2,35, výhodně 1,6 až 2,3.
- 5Podklad (1) podle nároku 1 nebo 2, vyznačený tím, že pojivém je alespoň částečně organické pojivo.
- 6Podklad (1) podle některého z předcházejících nároků, vyznačený tím, že alespoň část částic oxidu titaničitého obsahuje v jejich krystalové mřížce, ionty kovu •4 4444 - 46 zvoleného z množiny zahrnující železo, měň, ruthenium, cer, molybden, bismut, tantal, niob, kobalt, nikl a vanad.
- 7Podklad (1) podle některého z předcházejících nároků, vyznačený tím, že alespoň část částic oxidu titaničitého je pokryta alespoň částečně vrstvou oxidů nebo solí kovu zvoleného z množiny zahrnující železo, měd, ruthenium, cer, molybden, bismut, tantal, niob, kobalt, nikl, vanad, wolfram, cín, zirkonium, kadmium a zinek.
- 8Podklad (1) podle některého z předcházejících nároků, vyznačený tím, že alespoň část částic oxidu titaničitého je pokryta alespoň částečně vrstvou kovu zvoleného z množiny zahrnující platinu, stříbro a rhodium.
- 9Podklad (1) podle některého z předcházejících nároků, vyznačený tím, že povlak (3) obsahuje přídavné částice na bázi kadmia, cínu, wolframu, zinku, ceru *nebo zirkonia.
- 10Podklad (1) podle některého z předcházejících nároků, vyznačený tím, že povlak (3) má tloušťku 5 nm až 1 mikrometr, výhodně 5 až 100 nm.
- 11Podklad (1) podle některého z předcházejících nároků, vyznačený tím, že je podkladem na bázi skla nebo na bázi keramického nebo sklokeramického materiálu.
- 12Podklad (1) podle některého z předcházejících nároků, vyznačený tím, že pod povlakem (3) na bázi oxidu titaničitého je uložena alespoň jedna vrstva (2) mající antistatickou, tepelnou nebo optickou funkci nebo tvoří bariéru proti migraci alkalických kovů pocházejících z podkladu.
- 13Podklad (1) podle některého z předcházejících nároků, vyznačený tím, že tenká vrstva (2) s antistatickou funkcí mající případně regulovanou polarizaci nebo/a tepelnou funkcí nebo/a optickou funkcí je založena na vodivém materiálu kovového typu nebo typu dotovaného oxidu kovu, jakým je například oxid inditý dotovaný cínem (ITO), oxid ciničitý dotovaný fluorem (SnO 2 :F) nebo oxid zinečnatý dotovaný indiem (ZnO:In), fluorem (ZnO:F), hliníkem (ZnO:Al) nebo cínem (ZnO:Sn).
- 14Podklad (1) podle nároku 12,vyznačený tím, že tenká vrstva (2) s optickou funkcí je založena na oxidu nebo směsi oxidů, přičemž její index lomu leží mezi indexem lomu povlaku (3) a indexem lomu podkladu (1) a je zejména tvořena následujícími oxidy A^O^, SnO 2 , InO^ nebo oxykarbidem nebo oxynitridem křemíku.
- 15Podklad (1) podle nároku 12,vyznačený tím, že tenká vrstva (2) s bariérovou funkcí vůči alkalickým kovům je založena oxidu, nitridu, oxynitridu nebo oxykarbidu křemíku, oxidu hlinitém obsahujícím fluor (A1 2 O 2 :F) nebo nitridu hliníku.
- 16Podklad (1) podle nároku 12,vyznačený tím, že povlak (3) tvoří finální vrstvu soustavy antireflexních vrstev.
- 17Monolitní zasklívací materiál nebo vícevrstvý zasklívací materiál dvojitého nebo laminátového typu, ve kterém je zabudován podklad (1) podle některého z předcházejících • · · · · · - 48 nároků.
- 18Použití podkladu podle některého z nároků 1 až 16 pro výrobu samočisticího, antikondenzačního nebo/a špínu odpuzujícího zasklívacího materiálu, zejména použitelného jako zasklívací materiál ve stavebnictví pro dvojité zasklívání, pro zasklívání oken automobilů, vlaků nebo letadel ve formě předního, bočního nebo zadního skla, nebo užitkové zasklívání, zejména pro zasklívání akvárií, výloh obchodů, skleníků vnitřního vybavení, městského mobiliáře, zrcadel nebo jako televizních obrazovek nebo funkčních ploch s elektricky regulovanou proměnlivou absorpcí.
- 19Způsob výroby podkladu (1) podle některého z nároků 1 až 16,vyznačený tím, že se povlak (3) nanese pyrolýzou v kapalné fázi za použití disperze obsahující alespoň jednu organokovovou sloučeninu a částice oxidu titaničitého, přičemž uvedené částice oxidu titaničitého mají charakteristiky částic zabudovaných ve finálním povlaku (3).
- 20Způsob výroby podkladu (1) podle některého z předcházejících nároků 1 až 16,vyznačený tím, že se povlak (3) nanese technikou sol-gel za použití máčecí, komůrkové, laminární nebo naprašovací metody a za použití disperze obsahující alespoň jednu organokovovou sloučeninu a částice oxidu titaničitého, přičemž uvedené částice mají charakteristiky částic zabudovaných do finálního povlaku (3).
- 21Způsob podle nároku 19 nebo 20, vyznačený tím, že se použije disperze, jejíž poměr hmotnosti organokových sloučenin, vyjádřených jako oxidy kovů (MO ), k hmotnosti oxidu titaničitého dodaného částicemi a organokovovými sloučeninami, vyjádřenými jako oxidy (MO ), je roven X 5 až 80 %. •4 ···· • ·
- 22Způsob podle některého z nároků 19 až 21, v y z n ačený tím, že organokovové sloučeniny jsou sloučeninami na bázi titanu nebo křemíku.
- 23Způsob podle některého z nároků 19 až 22, v y z n ačený tím, že se povlak (3) nanese alespoň ve dvou stupních.
- 24Způsob podle některého z nároků 19 až 23, vyznačený tím, že se povlak (3) po nanesení podrobí alespoň jednomu tepelnému zpracování žíhacího typu.
- 25Organická disperze, vyznačená tím, že obsahuje:- částice oxidu titaničitého, které mají velikost 5 až 80 nm, jsou monodisperzní a mají převážně anatasovou krystalickou formu, - alespoň jednu organokovovou sloučeninu a - alespoň jedno organické rozpouštědlo, které má výhodně nižší skupenské teplo odpařování, než je skupenské teplo odpařování vody.
- 26Disperze podle nároku 25,vyznačená tím, že jako organické rozpouštědlo obsahuje rozpouštědlo zvolené z množiny zahrnující alkoholy, zejména glykoly, a estery, jako například ethylacetát.
- 27Disperze podle nároku 25 nebo 26, vyznačená tím, že jako částice oxidu titaničitého obsahuje částice získané mokrým preparativním postupem.
- 28Disperze podle nároku 27,vyznačená tím, že jako částice oxidu titaničitého obsahuje částice získané • · způsobem, který spočívá v hydrolýze alespoň jedné titanové sloučeniny A v přítomnosti alespoň jedné sloučeniny B zvolené z množiny zahrnující:i) kyseliny, které mají: - bu<5 karbonylovou skupinu nebo alespoň dvě hydroxylové nebo/a aminové skupiny, - nebo alespoň dvě karboxylové skupiny a alespoň jed- nu hydroxylovou nebo/a aminovou skupinu, ii) organické fosforečné kyseliny následujících vzorců HO 0 R2 0 OH \ II 1 II / P - (C)n - P / 1 \ HO R1 OH HO 0 OH 0 OH \ II I II / P _ C - P / I \ HO R3 OH HO O \ II ch 2 / 0 OH II / P _ OH HO P_CH 2 —[N— (CH 2 ) m ] p _N I \ CH 2 CH 2 I O = P- OH P_ OH II \ O OH OH ve kterých n a m znamenají celá čísla mezi 1 a 6 a p znamená celé číslo mezi 0 a 5, R1, R2 a R3, které jsou stejné nebo odlišné, znamenají hydroxylovou skupinu, amino-skupinu, aralkylovou skupinu, arylovou skupinu nebo alkylovou skupinu nebo atom vodíku, ·· ···· iii) sloučeniny schopné uvolňovat v kyselém prostředí síranové ionty a iv) soli výše popsaných kyselin, a v přítomnosti zárodečných krystalů tvořených anatasovým oxidem titaničitým a majících velikost nejvýše 5 nm, přičemž tyto zárodečné krystaly se použijí v takovém množství, že poměr hmotnosti oxidu titaničitého přítomného v zárodečných krystalech k titanu přítomnému před zavedením zárodečných krystalů v hydrolyzačním prostředí, vyjádřenému jako TiC^ činí 0,01 až 3 %.
- 29Disperze podle nároku 27 nebo 28, vyznačená tím, že částice jsou porézní.
- 30Disperze podle některého z nároků 25 až 29, vyznačená tím, že rovněž obsahuje alespoň jednu organokovovou sloučeninu na bázi kovu zvoleného z množiny zahrnující titan, křemík, cín, zirkonium a hliník.
- 31Disperze podle nároku 30,vyznačená tím, že organokovovou sloučeninou je sloučenina obecného vzorce M(0R)^, ve kterém M znamená kov zvolený z množiny zahrnující titan, křemík, cín, zirkonium a hliník a R znamená alkylovou skupinu, cykloalkylovou skupinu, arylovou skupinu, alkylarylovou skupinu, arylaikylovou skupinu, alkenylovou skupinu, alkinylovou skupinu, acetylacetonátovou skupinu nebo některý z jejích derivátů, amino-skupinu nebo některý z jejích derivátů nebo glykolátovou skupinu.
- 32Disperze podle některého z nároků 25 až 31, v y značená tím, že obsahuje takové množství organokovových sloučenin, že poměr hmotnosti těchto sloučenin, vyjádřených jako oxidy kovů (MO x ),k hmotnosti oxidu titaničitého dodaného částicemi a organokovovými sloučeninami, vyjádřenými jako oxidy kovů (MO ), činí 5 až 80 %. Λ 99 99»9
- 33Disperze podle některého z nároků 25 až 32, vyznačená tím, že obsahuje přídavné částice na bázi sloučenin kovu zvoleného z množiny zahrnující kadmium, cín, wolfram, zinek, cer a zirkonium.
- 34Disperze podle některého z předcházejících nároků 25 až 33,vyznačená tím, že alespoň část částic oxidu titaničitého disperze je dotovaná v jejich krystalové mří.žce ionty kovu zvoleného z množiny zahrnující železo, měd, ruthenium, cer, molybden, bismut, tantal, niob, kobalt, nikl a vanad.
- 35Disperze podle některého z nároků 25 až 34, vyznačený tím, že alespoň část částic oxidu titaničitého disperze je alespoň částečně pokryta vrstvou oxidů nebo solí kovu, přičemž kov je zvolen z množiny zahrnující železo, měň, ruthenium, cer, molybden, bismut, tantal, niob, kobalt, nikl, vanad, wolfram, cín, zirkon, kadmium a zinek.
- 36Disperze podle některého z nároků 25 až 35, vyznačený tím, že alespoň část částic oxidu titaničitého disperze je alespoň částečně pokryta katalyzátorem, zejména vrstvou kovu zvoleného z množiny zahrnující platinu, stříbro a rhodium.
- 37Použití disperze podle některého z nároků 25 až 36 při způsobu podle některého z nároků 19 až 24.
Independent claims37
363 paragraphs in 9 sections, as filed
Substrate with photocatalytic coating based on titanium dioxide and organic dispersions based on titanium dioxide
Field of technology
The invention relates to substrates provided with a titanium dioxide-based coating having photocatalytic properties, said titanium dioxide being partially incorporated in the coating in the form of particles. The invention also relates to a process for the preparation of these substrates and to novel organic dispersions based on monodisperse titanium dioxide particles which can be used in this process.
Prior art
It is known to modify materials intended for various uses, such as materials intended for use in vehicles or buildings (glass, metals, ceramics, facade and cladding materials and roofing materials, such as cladding tiles and slabs), by granting them specific properties, such as the ability to do not transmit ultraviolet rays, the ability to repel dirt, bactericidal properties, antireflective properties, antistatic properties and antimicrobial and similar properties.
Attempts have been made to modify the properties of said materials, in particular in the case of stained glass windows, including in particular vehicle windscreens, by applying a thin layer of specific material to the glass surface, which then imparts to the glass the properties required for the specific application.
Thus, layers with a certain optical function are known, for example so-called anti-reflective layers formed by a plurality of layers which have alternately high and low refractive index values. In order to achieve an antistatic function or a heating function, it is possible to provide the substrate with a thin layer of an electrically conductive material, for example based on metal or a doped metal oxide. To achieve an antisolar or low-emission thermal function, it is possible to use, for example, a thin layer of a metal of the silver type or a thin layer based on a metal oxide or nitride. To achieve a rain-repellent effect, the substrate can be provided with a layer having a hydrophobic character, for example a layer based on fluorinated organosilane.
Another desired property is to achieve a long-term good appearance of the material and such surface properties that would allow less frequent washing of the material and / or improved visibility through the material by removing dirt stains that gradually settle on the surface, especially dirty stains of organic origin, such as fingerprints or deposits of volatile organic products present in the atmosphere or even dirty condensation-type stains, immediately after their creation on the substrate.
The solution to the problem of said stains is, for example, to apply a coating to the substrate which mediates the degradation of said stains by photocatalysis. When exposed to radiation of the appropriate wavelength, the components of the coating initiate radical reactions which cause the oxidation of the organic products forming said dirty spots.
This degradation can be induced by any compound that forms radicals when exposed to light (photocatalytic effect). In particular, it may be titanium dioxide, which has already been used in the case of architectural and especially stained glass substrates.
Thus, for example, it is known to use solutions of titanium compounds or dispersions of colloidal titanium dioxide to achieve photocatalytic properties on a given substrate. However, it was found that the specific characteristics of these solutions • · • · • · · · • · · · ···· • · · · · · ···· ·· ·· ·· ··
- 3 titanium compounds or colloidal titanium dioxide dispersions used for the above-mentioned substrate treatment affect the quality of the achieved photocatalytic effect. The adhesion of the coating to the substrate also depends to a large extent on the specific characteristics mentioned. Finally, in the case where the substrate is glass, said coating can significantly reduce the transparency and uneven display of objects behind the glass.
It is therefore an object of the invention to provide new substrates with titanium dioxide-based coatings having good photocatalytic properties, said coatings being durable and transparent and which can be prepared in an industrially feasible manner.
The essence of the invention
This object is achieved by the invention, the object of which is to provide a substrate provided on at least one of its surfaces with a coating with photocatalytic properties based on titanium dioxide, which is at least partially crystalline and which is incorporated in said coating partly in the form of particles predominantly crystallized in anatase.
The invention also relates to a process for the preparation of said substrate, which comprises depositing the coating by liquid phase pyrolysis or a technique called solgel from a suspension containing at least one organometallic compound and a dispersion of titanium dioxide particles, said particles having the characteristics of particles incorporated in the final coating. .
Finally, the invention relates to an organic dispersion comprising:
- titanium dioxide particles between 5 and 70 nanometers in size which are monodisperse and have a predominantly anatase crystalline form, and • · • · · · · • · · · ······· ·· ···· ··· ··· ···· ·· ·· ·· ··
at least one organic solvent which preferably has a lower heat of vaporization than water.
This dispersion is useful for preparing the substrates of the invention.
Other advantages achieved by the invention will be apparent from the following description, examples and drawings, in which:
Fig. 1 shows a section of a substrate provided with a coating according to the invention,
Fig. 2 shows a diagram of the solgel coating technique realized by so-called dipcoating,
- Fig. 3 shows a cell-coating technique,
Fig. 4 shows a diagram of the so-called spray-coating technique and
Fig. 5 shows a scheme of coating formation by laminar impregnation technique.
The invention thus relates in particular to a substrate provided on at least one of its surfaces with a coating having photocatalytic properties based on titanium dioxide, which is at least partially crystalline and which is incorporated in said coating partly in the form of particles predominantly crystallized in the form of anatase.
In total, the titanium dioxide of the coating in particulate or other form is partially crystallized in the form of anatase or rutile or in the form of anatase and rutile with a degree of crystallization preferably equal to at least 25% and in particular equal to about 30 to 80%. Said degree of crystallization is also here
• · · · • · • · · · · • · · · · · · · · · · • · · · · ···· • · · · · ······· • · · · · · ·<·· ······· ·· ·· ·· · ·
- 5 is defined as the mass amount of crystalline titanium dioxide based on the total mass of titanium dioxide present in the coating.
As for the titanium dioxide particles, the nature of their crystalline phase is preferably predominantly anatase crystalline form.
The term predominantly herein means that the anatase content of the titanium dioxide particles in the coating is greater than 50 weight percent. The coating particles preferably have an anatase content higher than 80%.
The degree of crystallization and the nature of the crystalline phase are measured X-ray.
The crystalline titanium dioxide particles incorporated in the coating have a mean size between 5 and 70 nm, more preferably between 10 and 50 nm. Particle diameters are measured by transmission electron microscopy (TEM).
The titanium dioxide particles are preferably incorporated into the coating using a binder.
According to a first alternative form, the binder by means of which the titanium dioxide particles are incorporated in the coating may be an inorganic binder. Such a binder may in particular be in the form of an amorphous or partially crystalline oxide (or a mixture of oxides), for example in the form of silica, titanium dioxide, tin dioxide, zirconia or alumina. Such a binder can be limited to fulfilling the function of a binder matrix, as in the case of silica. However, such a binder may also contribute to the photocatalytic action of the particles by exhibiting itself to some extent, even to a small extent compared to the photocatalytic action, as is the case with amorphous or partially crystalline titanium dioxide.
• · <· · ···· · · ·· • · · · · · · ···· • · · · · · · · · · · · · ··· «··· • · ··· · ··· ······· ti 9 9 9 9 9 9
In the second alternative form, the binder may be at least partially organic in nature, in particular in the form of a polymer matrix. This may apply to polymers which have properties which are complementary to the properties of the titanium dioxide particles, and in particular hydrophobic and / or oleophobic properties.
Examples of such matrices are given, for example, in EP-A-675,087, which describes hybrid matrices obtained from a solution containing an epoxide-containing alkoxysilane, a hydrolyzable epoxide-free silane, colloidal silica, a catalyst and at least one hydrolyzable fluorinated alkylsilane. Said fluorinated alkylsilane has the general formula wherein n is a number from 0 to 12, m is a number from 2 to 5 and X is a hydrolyzable functional group. The alkylsilane-containing epoxide has the general formulas
CH<sub>n</sub>-CM-CH 2 -O- (CH 2 -CH 2 -O) - (CH<sub>O</sub>) -Si (0M ')<sub>O</sub>
I 2 2 2 r 2 s | 3-p
OM
P in which p has the value 0 or 1, r has the value 0, 1 or 2, s represents an integer between 1 and 6, M represents a hydrogen atom or an alkyl group containing 1 to 4 carbon atoms and M 'and M represent alkyl groups containing 1 to 3 carbon atoms.
The epoxy-free silane has the general formula
Ν '
Q - Si - Q '
N wherein N and Ν 'represent organic groups attached to the silicon atom by a Si-C bond and not containing a group capable of reacting with the hydrolyzable silanes present in the composition, and Q and Q<sup>of</sup> means hydrolyzable functional groups.
It is also possible to apply to the coating according to the invention a layer having an oleophobic and / or hydrophobic character, for example a layer based on fluorinated organosilane described in US-A-5,368,892 and US-A-5,389,427 and perfluoroalkylsilane described in EP-A692. 463 and having the general formula
CF-j- (CF<sub>0</sub> ) - (CH<sub>0</sub> ) _- SiX<sub>7</sub>
2 n is 2 m 3 in which n represents a number from 0 to 12, m represents a number from 2 to 5 and X represents a hydrolyzable functional group.
Due to the titanium dioxide particles incorporated in the coating, the coating can have a refractive index value between 1.40 and 2.35, preferably between 1.6 and 2.3. This is due to the fact that the titanium dioxide particles are porous and thus have a lower refractive index than the total titanium dioxide. Thus, the coatings thus obtained have a lower refractive index than coatings based on non-specific titanium dioxide.
The optical properties associated with achieving lower refractive index values are very important in the case of glass-based substrates: a layer with a high refractive index value of non-specific titanium dioxide results in an increased proportion of reflected light by the glass substrate and thus ·· ···· reduced light transmission through the substrate. In some applications, especially in the field of vehicle windows, it is important for the glass substrate to have a high value of light transmission (for vehicle windscreens, it must have a minimum light transmission of 75%).
In order to enhance the photocatalytic effect of the titanium dioxide coating particles according to the invention, said particles may contain catalysts and additives which better filter UV radiation or shift the absorption band into the visible light region, or metals which do titanium dioxide doping, in particular to increase the number of electron carriers. Some alternative embodiments of the invention allow the photocatalytic effect to be enhanced.
According to a first alternative form, at least part of the titanium dioxide coating particles may contain in their crystal lattice metal ions selected from the group consisting of iron, copper, ruthenium, molybdenum, bismuth, tantalum, niobium, cobalt, nickel or vanadium. The weight ratio of these ions to the weight of the titanium dioxide particles is generally between 0.01 and 10%.
According to a second alternative form, at least part of the titanium dioxide particles may be at least partially covered by a layer of metal oxides or salts, said metal being selected from the group consisting of iron, copper, ruthenium, cerium, molybdenum, bismuth, tantalum, niobium, cobalt, nickel, vanadium, tungsten, tin, zirconium, cadmium or zinc. The weight ratio of these metals to the weight of the titanium dioxide particles is generally between 0.01 and 20%.
According to a third alternative form, at least part of the titanium dioxide particles may be covered at least in part by a layer of metal selected from the group consisting of platinum, silver and rhodium. The weight ratio of these metals to the weight of the titanium dioxide particles is between 0.01 and 5%.
·· ·»*·
According to a fourth alternative form, the coating according to the invention comprises, in addition to the titanium dioxide particles, further particles based on metal compounds selected from the group consisting of cadmium, tin, tungsten, zinc, cerium and zinc. These particles have a colloidal size, generally between 5 and 100 nm. The weight ratio of these additional particles to the weight of the titanium dioxide particles is generally between 0.01 and 20%.
These further particles may be metal sulphides or oxides, such as cerium dioxide, tin dioxide, tungsten oxide, zinc oxide, zirconia or a compound of formula CdSe ^ S ^, in which x and y have a value between 0 and 1 and the sum of x + y is equal to 1.
The thickness of the coating on the substrate according to the invention is variable. It is generally between 5 nm and 1 micrometer, preferably between 5 nm and 100 nm, even more preferably between 5 and 80 nm and in particular between 10 and 80 nm. This thickness can be, for example, 20 to 50 nm. In fact, this thickness will depend on certain parameters. For example, it may depend on the intended use of the substrate or alternatively on the particle size of the titanium dioxide in the coating. The coating can also be designed to have a more or less glossy surface. A certain degree of surface roughness may be advantageous when it allows larger catalytically active areas to be formed. Such a surface roughness, on the other hand, is undesirable because it promotes the incrustation of dirt on the surface of the coating. In the case where the coating is formed by titanium dioxide particles embedded in a binder, the deposition technique and the thickness of the coating may be chosen so that the particles or crystallites forming the coating protrude from the surface of said coating.
The substrate according to the invention can have a different nature. It can be any type of architectural material (metals, concrete and the like, as well as substrates based on glass, ceramic materials or glass-ceramic materials).
• · · · • · • · · · · · · · ·· • · · · ····· • e β · · ·· · · · ·· • · · · · · · ·· ··· ···· ·· ·· ·· ··
It is also possible to place one or more other thin layers between the substrate and the coating according to the invention with different or functions complementary to the functions of the titanium dioxide-based coating. In particular, they can be layers with an antistatic, thermal or optical function or layers forming a barrier to the migration of certain elements originating from the substrate, for example forming a barrier for alkali metals and especially for sodium ions when the substrate is made of glass. It is also possible to use a system of thin layers with alternating high and low refractive index forming an antireflection type layer, the coating according to the invention forming the final layer of said layer system. In this case, it is preferred that the coating has a relatively low refractive index of 10, which is the case when it contains an inorganic matrix of the silica type in which the titanium dioxide particles are encapsulated, or when it is formed by a mixed oxide of titanium and silicon.
As a layer with an antistatic or thermal function (heating layer operating on the basis of a supply current, a low emissive layer, an antisolar layer and the like), a layer based on a conductive metal type material such as silver or a doped oxide can be used. a metal such as a layer based on tin-doped indium oxide (ITO), fluorine-doped tin dioxide (SnCl 2) or indium-doped zinc oxide (ZnO: In), fluorine (ZnO: F), aluminum (ZnO: Al) or tin (ZnO: Sn).
Such layers can be obtained by powder pyrolysis from dibutyltin difluoride (DBTF) or by liquid or vapor phase pyrolysis as described in patent application EP-A648,196. In the vapor phase, it is possible in particular to use a mixture of monobutyltin chloride and a fluorinated precursor, optionally in combination with a mild oxidizing agent of the type 10.
The layer with an antistatic function preferably has a surface resistance value of 1000 ohms per unit area. It is possible • · «· · ···· ♦ ♦ · · • · · · · · · · · · • · · · ·· * ·· • e ♦ · · ·· · · · ·· • · · ···· ··· ···· · »···· ··
- 1 1 provide this layer with a current supply in order to polarize it (supply voltage, for example 5 to 100 V). Such controlled polarization makes it possible to control the deposition of dust with a particle size of the order of millimeters on said coating, this dust adhering to the surface of the coating due to electrostatic forces. A sudden change in the polarity of the antistatic layer will cause dust to be expelled from the surface of the layer.
An optical function thin film can be used to reduce light reflection and / or to neutralize the color of the light reflected by the substrate. In this case, it is preferred that the refractive index of this layer lies between the refractive index of the coating and the refractive index of the substrate and the layer has an appropriate optical thickness, and may be an oxide or mixture of oxides selected from alumina, tin dioxide and indium oxide. consists of silicon oxycarbide or oxynitride.
In order to achieve maximum neutralization of the color of the reflected light, it is preferred that this thin layer have a refractive index close to the square root of the product of the squares of the refractive indices of the two materials surrounding it, i.e. the refractive indices of the substrate and its coating. It is also advantageous to select the optical thickness of said layer (i.e. the product of its geometric thickness and its refractive index) in the lambda / 4 region, where lambda is approximately the mean wavelength in the visible region, in particular approximately 500 to 550 nm.
The titanium dioxide-based coating preferably forms the final layer of the system of anti-reflective layers.
The alkali metal barrier film may be a layer based on oxide, nitride, oxynitride or oxycarbide of silicon or alumina containing fluorine (SiCl 2) or alternatively based on aluminum nitride. This layer has been shown to be useful when ♦ 0 • 0 · 0 • 000 0 · · · · · · 0 0 0 0 ···· • 0 · 0 · 0 0 ··· 0 · • 0 000 · 000 000 0000 00 00 ·· · ♦
- 12 the substrate is glass, as due to the migration of sodium ions into the titanium dioxide coating, it could, in certain circumstances, have an adverse effect on the photocatalytic properties of the coating.
All of the above-mentioned thin layers can be applied by vacuum cathodic sputtering techniques or thermally decomposable type techniques, such as solid, liquid or gas phase pyrolysis deposition techniques. Each of the above layers may include a combination of several functions, although it is also possible to apply the individual layers to each other. Such a layer can be obtained by CVD (Chemical Vapor Deposition) technique from a mixture of SiH 2 and ethylene diluted with nitrogen, as described in patent application ΕΡ-Ά-518,755.
Surprisingly, the substrate according to the invention actually performs not only one but two functions when exposed to appropriate radiation, such as visible light and / or ultraviolet light: due to the presence of photocatalytic titanium dioxide, it causes the gradual disappearance of dirt of organic origin by: causes its decomposition by a radical oxidation mechanism.
The substrate according to the invention may also have an outer surface with a purely hydrophilic and / or oleophilic character, in particular in the case where the binder is an inorganic binder, which offers two not insignificant advantages. In particular, the hydrophilic nature of the outer surface allows the coating to be completely wetted with water: instead of forming droplets in condensation form which impairs visibility, only a completely transparent continuous thin film of water can be observed which forms on the surface of the substrate. This anti-condensation effect can be controlled by measuring the contact angle with water of less than 5 ° after exposure to light.
Simultaneously with the hydrophilic character of the surface, it may have • · ···· · · ····· • · · · ♦ ···· • · «· · · · 99 · ·· • · · · ···· · ·· ···· ·· ·· ·· «·
The substrate according to the invention is also oleophilic in nature, which makes it possible to wet the organic dirt, which, like water, then tends to deposit on the substrate in the form of a continuous film which is less visible than well-localized dirty spots. In this way, an organic dirt-repellent effect is achieved, which takes place in two stages: once the organic dirt settles on the substrate, it is only slightly visible at this point due to its decomposition into a thin coating, followed by its thin coating. gradual disappearance due to radical degradation initiated by photocatalysis.
The invention is particularly directed to soil-repellent and / or anti-condensation glasses, either in the form of monolithic or multiple units of the double or laminate type, which are flat or curved and which contain the above-mentioned substrates.
Such glasses find use in the construction industry, for example in the realization of double glazed surfaces (it is possible to apply a coating on the outer and / or inner side of the glazed surface, i.e. on side 1 or / and 4). The use of said glasses is particularly advantageous in places which are not easily accessible for cleaning and / or which have to be cleaned very often, for example roof glass, glazed areas at airports and the like. These glasses can also be used as window windows for vehicles, for which maintaining good visibility is an essential safety factor. The coating according to the invention can thus be applied to the windscreen of an automobile, to its side windows and to its rear window, in particular to the surface of these windows, which faces the interior of the vehicle cabin. Said coating may prevent the formation of condensation spots and / or may cause the disappearance of dirt after fingerprints, nicotine or organic substances, which are volatile plasticizers released from the plastic lining of the interior of the vehicle cabin, especially from the dashboard (this release is sometimes known as
99 ·· 9999 99··
9 9 9 9 9 9 9 9 99
9 9 9 9 99 9 9
9999 9999999
9 9 9 9 9 9 99
999 9999 99 99 9999
- 14 fogging).
Other possible applications are also possible, such as glass for aquariums, shop windows, greenhouses, interior fittings, urban furniture, mirrors, television screens or glasses with electrically adjustable variable absorption.
Another advantageous application of the coating according to the invention consists in combining this coating with glasses with electrically controlled variable absorption of the following types: electrochromic glasses, glasses based on liquid crystals, optionally with dichroic dye, glasses containing a suspended particle system, viologen glasses, etc. All these types of stained glass are generally formed by a plurality of transparent substrates, between which active elements are arranged, it being possible to deposit said coating on the outside of at least one of these substrates.
Particularly in the case of electrochromic glasses, where these glasses are in a colored state, the absorption of the glass can lead to some heating of the surface and this heating is able to accelerate the photocatalytic decomposition of carbonaceous substances deposited on the titanium dioxide coating. Further details regarding the structure of electrochromic glasses can be found in patent application EP-A-575,207, which describes an electrochromic laminated double glass in which it would be advantageous to apply a titanium dioxide coating on page 1.
Another object of the invention is to provide various methods for producing the substrates described above.
In a first embodiment, the method for producing said substrate comprises applying the coating by liquid phase pyrolysis using a dispersion comprising at least one organometallic compound and titanium dioxide particles, said particles having the characteristics of particles incorporated in the final coating described above.
The technique of applying the coating by pyrolysis is advantageous in view of: · · · · * · ··· · · · · • * «· · ······· • · · w w · ··· ··· ···· ·· «· ·· · ♦
- 15 d in that it allows the continuous application of the coating directly to the float glass strip in the case where glass is used as a substrate.
In a second embodiment, the method for producing the substrate consists in applying the coating by sol-gel technique using dip-coating, cell-coating or spraycoating deposition or using laminar coating and using a dispersion containing at least one organometallic compound and oxide particles. titanium dioxide, said particles having the characteristics of particles incorporated in the final coating described above.
The principle of the so-called sol-gel technique using the dip coating method can be seen in Figure 2. This coating consists of immersing the substrate in a liquid dispersion 4 containing the respective coating components 3 and subsequently pulling the substrate out of the liquid dispersion 4 at a controlled rate using motor means 5. . The choice of the rate of withdrawal of the substrate from said dispersion will make it possible to set the desired thickness of the dispersion adhering to both surfaces of the substrate and thus also the thickness of the coating applied to the substrate after its heat treatment. This heat treatment is simultaneously aimed at evaporating the solvent, decomposing the organometallic compound or organometallic compounds into oxides and decomposing the mechanical behavior of the coating.
The principle of cell coating (so-called cell-coating technique) is evident from Fig.3. This technique consists in creating a narrow cavity defined by two substantially parallel surfaces 6 and 7 and two seals 8 and 7, at least one of said surfaces 6 and 7 being<sup>E</sup> formed by the surface of the substrate 1 to be provided with said coating. The cavity is filled with a dispersion containing an organometallic compound or organometallic compounds and titanium dioxide particles, after which the dispersion is removed from the chamber at a controlled rate so that the dispersion forms a wettable meniscus, for example in a · · • · · · • · · · · • · · · ♦ ·· · · • * «·· · ♦ ····· • · · · · ·· · · ··· ···· ·· ·· ·· ·
- 16 the use of a peristaltic pump 10, the dispersion to that extent<sub>(</sub>as it is discharged from the chamber<sub>of</sub>leaves a thin film of said dispersion on said surface of the substrate 1. The cavity 5 is then retained for the time necessary to dry and cure the coating on the substrate by heat treatment. The advantage of this technique over the dip coating technique is that it is possible to coat only one of the surfaces of the substrate and not both surfaces at the same time, which would only be achieved with the dip technique using a mask.
The principle of the sputtering technique is explained in detail in Fig. 4. This technique consists in spraying a dispersion 4, which contains an organometallic compound or organometallic compounds and titanium dioxide particles, in the form of a mist against the substrate 1 in a static state.
The principle of the laminar coating technique is shown in Fig. 5. This technique consists in guiding a substrate 1 pressed by a vacuum against a support 11 made of stainless steel and Teflon over a tank 12 containing a dispersion containing organometallic compound or organometallic compounds and titanium dioxide particles A cylinder 14 provided with a slot is partially immersed in said dispersion. The combination of the tank 12 and the cylinder 14 then moves along the entire length of the substrate J, the mask 13 preventing excessive evaporation of the solvent from said dispersion 4. A more detailed description of this application technique can be found in patent application WO94 / 01598.
In the latter method, the organometallic compound or organometallic compounds are thermally decomposed after coating the substrate on one or both sides with said dispersion.
In both of the above methods, a dispersion based on an organometallic compound or organometallic compounds and already formed and crystallized titanium dioxide particles is used.
• 4 4 · • 4 · 4 · · · 4 4 4 · • 4 4 4 4 4 4 4 4 • 4 · · 4 44 4444·
4 4444 4 44
4 4444 44 ·« 44·♦
Said organometallic compounds are compounds in which the metal atom M may be selected from the group consisting of titanium, silicon, tin, zirconium, aluminum and similar metals.
These may be organometallic compounds of formula M (OR), in which M is a metal selected from the group consisting of, for example, titanium, silicon, tin, zirconium or aluminum and R is alkyl, cycloalkyl, aryl, alkylaryl or arylalkyl. , an alkenyl group or an alkynyl group, an acetylacetonate group or one of its derivatives (methylacetoacetate, ethylacetoacetate, titanacetylacetonate and the like) an amino group or one of its derivatives (titanetriethanolamine, titanediethanolamine and the like), a glycolate group (titanium tetraoctylene glycolate) and the like.
Compounds of the titanate and silicate types are preferred compounds.
Tetraisopropoxytitanium is particularly suitable as the organometallic compound. Preferred organometallic titanium compounds are compounds of the titanium chelate and / or titanium alkoxide type, which may be those described in patent application FR-A-2,310,977 and in European patent application EP-A-465,309. Thus, the organometallic titanium compounds may be selected from the group consisting of R<sub>n</sub>Ti (OR ') p, in which p represents a number between 1 and 4, n represents 4-p,
R represents an alkyl group containing 1 to 18 carbon atoms and
R 'represents an alkyl group containing 1 to 4 carbon atoms, in particular a methyl group, an ethyl group or an isobutyl group.
Preferred silicon organometallic compounds may be selected from the group consisting of compounds of the formula
- 18 • ·
<img file="CZ9800756A3_D0001.tif" />
R Si (OR '), in which npp represents a number between 1 and 4, n represents 4-p,
R represents an alkyl group containing 1 to 18 carbon atoms and
R 'represents an alkyl group containing 1 to 4 carbon atoms, in particular a methyl group, an ethyl group or an isobutyl group.
Preferred compounds are tetramethyorthosilicate (TMOS), tetraethylorthosilicate (TEOS) and a compound of formula (CH<sub>3</sub>)<sub>2</sub>Si (OC<sub>2</sub>H<sub>5</sub>)<sub>2</sub>.
Of course, it is also possible to use mixtures of these compounds.
The titanium dioxide particles have the characteristics described above with respect to their size, degree of crystallinity and, optionally, doping with metal compounds.
Said dispersion generally contains 5 to 90% by weight of organometallic compounds, expressed as oxides (MO), based on the weight of titanium dioxide provided by said particles and organometallic compounds, expressed as oxides (MO), said dispersion preferably containing 15 to
X% and more preferably 20 to 75% of said organometallic compounds.
After application and heat treatment, the coating may contain both titanium dioxide originating from the decomposition of organometallic compounds, if these compounds consist of titanium organometallic compounds, and titanium dioxide forming titanium dioxide dispersion particles, the first titanium dioxide forming an inorganic binder for the second titanium dioxide. forming dispersion particles.
Titanium dioxide particles are highly effective in the level of photocatalytic activity and, in addition, can promote the crystallization of titanium dioxide formed by the thermal decomposition of titanium-based organometallic compounds, which are likely to act as seed crystals. Titanium dioxide of two different origins is thus present in the final coating.
It is advantageous to use monodisperse titanium dioxide particles in order to obtain transparent coatings. The term monodisperse here means that said particles have a dispersion index of at most 0.5, preferably at most 0.3, said dispersion index being defined by the following formula:
<sup>0</sup>84 ’ <sup>0</sup>16 wherein the particle diameter for which 84% of the particles have a diameter of less than 0θ is a particle diameter for which 16% of the particles have a diameter of less than 0θ, and
0, -θ means the mean particle diameter.
In addition, it may be advantageous to apply the coating - and this applies to any application technique - not in a single step, but in at least two successive steps, which seems to promote crystallization of titanium dioxide throughout the thickness of the coating if a relatively thick coating is used.
It may also be advantageous to subject the coating to at least one heat treatment by annealing after it has been applied.
Such annealing heat treatment is particularly important when the coating has been applied by sol-gel or laminar techniques in the second process described above in order to decompose the organometallic compound or organometallic compounds into an oxide after said coating has been carried out.
On the other hand, such heat treatment by annealing is not essential in the case where the coating has been applied by pyrolysis in the first process described above, in which the organometallic compound decomposes when it comes into contact with the substrate. However, in both the first and second methods, the post-deposition heat treatment, once the titanium dioxide has been formed, improves the degree of crystallization and adhesion of the coating. In addition, the heat treatment temperature used may allow better control of the degree of crystallization and a specific choice of the crystalline character of said particles.
Said heat treatment by annealing consists in introducing the substrate into an oven, where it is exposed to a temperature of about 500 to 550 ° C for 1 minute to 3 hours.
In the first and the second of these methods, it may be useful to use an alkali metal barrier layer between the substrate and the coating according to the invention, especially when the coating is to be subjected to a relatively long or high temperature heat treatment, because heat affects the migration of alkali metals from the glass substrate to the coating, and the increased alkali metal content of the coating can in turn adversely affect the photocatalytic activity of the coating. The use of said barrier layer is also useful in the case where the coating has a relatively small thickness and in particular in the case where the thickness of this coating is less than 20 nm.
Any type of titanium dioxide dispersion can be used in the present invention in which the titanium dioxide particles have properties desirable for the substrate, in particular in terms of the size and crystallinity of said particles, both when the liquid carrier medium is water and when wherein said liquid carrier medium is an organic phase.
Finally, the invention relates to an organic dispersion comprising: - titanium dioxide particles having a size of me · · · · · · · 9 9 9 · · · · · · ·· «· • · · · ·« · · ··· • · · · · ··· of 5 and 70 nm, which are monodisperse and have a predominantly crystalline anatase form, and
at least one organic solvent, the heat of vaporization of which is preferably lower than the heat of vaporization of water.
Here, too, the term monodisperse must be understood as defined in the preceding text.
The titanium dioxide particles here have the same size and crystallinity as the coating particles on the substrate according to the invention, these characteristics already having been defined above.
Thus, the titanium dioxide particles present in said dispersion have a size between 5 and 80 nm, preferably between 5 and 70 nm and even more preferably a size between 10 and 50 nm. This size is measured by transmission electron microscopy (TEM).
In addition, the nature of the crystalline phase of said titanium dioxide particles has a predominantly anatase crystalline form. The term predominantly means here that the anatase content of the titanium dioxide particles contained in the dispersion according to the invention is higher than 50% by weight.
Preferably, the titanium dioxide particles contained in the dispersion according to the invention have an anatase content of more than 80%.
With respect to said liquid carrier phase, the organic solvent used preferably has a group heat of vaporization lower than the group heat of vaporization of water. The term heat of vaporization as used herein means the number of calories required to evaporate 1 g of liquid at the boiling point of said liquid. The heat of vaporization of water at its boiling point is 540 calories per gram of evaporated water (Handbook of Chemistry and Physics, 75...). Such organic • φ · «« *
The solvent may be selected from the group consisting of alcohols (ethanol, isopropanol, etc.), especially glycols (ethylene glycol), esters such as ethyl acetate, and the like.
The titanium dioxide content of the dispersion according to the invention can be between 1 and 300 g / l.
Said organic dispersions may contain, depending on the type of process by which they were prepared, water in an amount of at most 10% by weight, preferably at most 5% by weight and even more preferably in an amount of at most 1% by weight.
Monodisperse titanium dioxide particles are generally obtained by the so-called solution or wet preparative process (thermolysis, thermal hydrolysis or precipitation of a titanium salt) in contrast to processes in which high-temperature pyrolysis or oxidation of the titanium salt is carried out. These may be, for example, titanium dioxide particles obtained by the method described in patent application EP-A-0,335,773.
In particular, it may be a process for hydrolysing at least one titanium compound A in the presence of at least one compound B selected from the group consisting of:
(i) acids having:
- either a carboxyl group and at least two hydroxyl and / or amine groups,
- or at least two carboxyl groups and at least one hydroxyl and / or amine group, ii) organic phosphoric acids of the following formulas:
HO O R2O OH \ II I.II /
P - (C)<sub>n</sub> - P / 1 \ HO R1OH • 4 · · · ·
- 23 HO O \ II
P _ /
HIM
O OH II /
P \
OH
HIM
CH<sub>2</sub>_ [N_ (CH<sub>2</sub>)<sub>m</sub>j<sub>p</sub>-N
I \
CH<sub>2</sub> /
O OH
II /
P _ OH
CH<sub>2</sub>
AND
O = P_ OH I OH
CH<sub>2</sub>_
P- OH
II \
O OH in which nam represents integers between 1 and 6 and p represents an integer between 0 and 5, R 1, R 2 and R 3, which are the same or different, represent a hydroxyl group, an amino group, an aralkyl group, an aryl group, an alkyl group or a hydrogen atom, iii) compounds capable of releasing sulphate ions in an acidic medium and iv) salts of the acids described above, and in the presence of anatase titanium oxide seed grains having a size of not more than 5 nm, wherein the weight ratio of titanium dioxide present in said seed crystals to titanium present before the introduction of the seed grains into the hydrolysis medium and expressed as TiCl 4 is 0.01 to 3%.
Said method for preparing titanium dioxide particles comprises several steps, the first step being the preparation of a starting solution containing titanium compound A, compound B as defined above and titanium dioxide seed crystals.
This starting solution to be hydrolyzed is preferably entirely exclusively an aqueous solution. Another solvent, «·
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«« ···· * · · • · * • ♦ · · • 4> · «·· * r • · 9 • ·· ··· ·« • · · ·· ·· such as alcohol can be optionally added provided that the titanium compound A and the compound B are then substantially soluble in said solvent mixture.
As for the titanium compound A, a compound selected from the group consisting of halides, oxyhalides, alkoxides, sulfates and especially synthetic titanium sulfates is generally used.
The term synthetic sulfates is understood here to mean solutions of titanyl sulfate prepared by ion exchange from very pure solutions of titanium tetrachloride or by reaction of sulfuric acid with titanium alkoxide.
Said preparations are preferably carried out using titanium compounds of the titanium halide or oxyhalide type. Commonly used titanium halides or oxyhalides are titanium fluorides, chlorides, bromides and iodides (or oxyfluorides, oxychlorides, oxybromides and titanium oxyiodides).
In a particularly preferred form, the titanium compound is titanium oxychloride TiOC 4.
The amount of titanium compound A present in the solution to be hydrolyzed is not a critical parameter.
Said starting solution additionally contains at least one compound B as defined above. Non-limiting examples of compounds B suitable for use in the invention include in particular:
-hydroxypolycarboxylic acids and in particular hydroxydine or hydroxytricarboxylic acids, such as citric acid, maleic acid and tartaric acid,
- (polyhydroxy) monocarboxylic acids, such as glucoheptonic acid and gluconic acid,
-poly (hydroxycarboxylic) acids, examples of which are, for example, tartaric acid,
-dicarboxylic amino acids and their corresponding amides, such as aspartic acid, asparagine and glutamic acid,
-hydroxylated or non-hydroxylated monocarboxylic amino acids, such as lysine, serine and threonine,
-aminotri (methylenephosphonate), ethylenediaminotetra (methylenephosphonate), triethylenetetraaminohexa (methylenephosphonate), tetraethylenepentaaminohepta (methylenephosphonate) or pentaethylenehexaaminoocta (methylenephosphonate),
-methylenediphosphonate, 1,1-ethylenediphosphonate, 1,2-ethylenediphosphonate, 1,1-propylenediphosphonate, 1,3-propylenediphosphonate, 1,6-hexamethylenediphosphonate, 2,4-dihydroxypentamethylene-2,4-diphosphonate, 2,5-dihydroxyhexamethylene -2,5-diphosphonate, 2,3-dihydroxybutylene-2,3-diphosphonate, 1-hydroxybenzyl 1,1-diphosphonate, 1-aminoethylene-1,1-diphosphonate, hydroxymethylene diphosphonate, 1-hydroxyethylene 1,1-diphosphonate , 1-hydroxypropylene-1,1-diphosphonate, 1-hydroxybutylene-1,1-diphosphonate or 1-hydroxyhexamethylene-1,1-diphosphonate.
As already mentioned, it is also possible to use as compound B all the salts of the abovementioned acids. Such salts are in particular alkali metal salts, preferably sodium salts, or ammonium salts.
These compounds may also be selected from the group consisting of sulfuric acid, ammonium sulfate, potassium sulfate and the like.
The compounds B defined above are preferably carbon.
<img file="CZ9800756A3_D0003.tif" />
·· · · · · ·· · · • · · · · · ♦ • · · · · · · • · · · 9) ···· · • · · · · · · •· ·· ·· *·
- 26 dike compounds of the aliphatic type. In this case, the length of the main hydrocarbon chain preferably does not exceed 15 carbon atoms, and more preferably does not exceed 10 carbon atoms.
The amount of compound B used is not a critical parameter. The molar concentration of compound B relative to the concentration of titanium compound A is generally 0.2 to 10%, preferably 1 to 5%.
Finally, said starting solution contains seed crystals of titanium dioxide used in a specific embodiment of said process.
Said titanium dioxide seed crystals used in the context of the invention must in particular have a size of less than 8 nm, measured by X-ray diffraction. Preferably, titanium dioxide seed crystals having a size between 3 and 5 nm are used.
Furthermore, it is necessary that the weight ratio of titanium dioxide present in the seed crystals to titanium present in the hydrolysis medium before the introduction of the seed crystals, i.e. titanium supplied by the titanium compound A, and expressed as TiO 2 'be<sup>3</sup>· <sup>mez3</sup>· Θ / θ<sup>1 and</sup> 3%. This ratio can advantageously be 0.05 to 1.5%. Fulfillment of both of these conditions (size and weight ratio) in combination with the method described above allows precise control of the final particle size of the titatin dioxide, the content of seed crystals being related to the stated particle size. In this way, it is possible to obtain particles whose size is between 5 and 100 nm.
Seed crystals in anatase form are used so that these seed crystals induce precipitation of titanium dioxide in anatase form. In general, due to their small size, these seed crystals are rather in the form of poorly crystallized anatase. These seed crystals are usually in the form of an aqueous suspension of titanium dioxide. They can generally be obtained in a manner known per se by neutralizing the titanium salt with a base.
• · · · • · • ·« · · ···· ·· · · ·· · • ···· · · ··
0 · · · · ♦ ···· · • · · · · · ··· ·····«· ·· · · · · ··
- 27 The next step consists in hydrolysing said starting solution in any manner known per se and generally by heating. In the latter case, the hydrolysis can advantageously be carried out at a temperature higher than or equal to 70 ° C. It is also possible to carry out the hydrolysis first at a temperature lower than the boiling point of the reaction mixture and only then to maintain the hydrolysis medium at its boiling point.
After completion of the hydrolysis, the obtained titanium dioxide particles are isolated by separating the precipitated solid from the mother liquor, after which the particles thus isolated are resuspended in an aqueous liquid medium to obtain a titanium dioxide dispersion. Said aqueous liquid medium may be acidic or basic. It is preferably an acidic solution, for example an aqueous solution of nitric acid or hydrochloric acid.
In order to obtain an organic dispersion of said titanium dioxide particles, it is possible to use any known process which makes it possible to suspend the titanium dioxide particles in the organic phase from an aqueous dispersion of titanium dioxide.
Said dispersion can thus be obtained by contacting an aqueous dispersion of titanium dioxide particles with a desired organic solvent and then heating to remove water by distillation. Such a process can only be used if the organic solvent used has a boiling point higher than the boiling point of water and is soluble in water. This is the case, for example, with ethylene glycol.
Said dispersion can also be obtained by grafting a hydrophobic chain to the surface of titanium dioxide particles suspended in water and then mixing with a water-immiscible organic solvent to achieve migration of titanium dioxide into the organic phase.
Titanium dioxide particles have been found to be derived from · · • · • · · ·· · ···· • · · · · ···· • · · · · · · ··· · · · · · · · · ·· ♦ ··· ···· ·· ·· ·· ··
- 28 resulting from the so-called solution or wet preparative process and originating in particular from the above-described hydrolysis carried out at a temperature of approximately 100 ° have, due to their porosity, a lower refractive index than titanium dioxide particles derived from other preparative processes. As already mentioned above, this fact is of considerable importance in the case where said titanium dioxide particles are used for the preparation of a coating on a substrate, specifically on a glass-based substrate, because the coating thus obtained also has a low refractive index value, as mentioned above. .
The liquid phase of the dispersion according to the invention preferably contains at least one organometallic compound based on a metal selected from the group consisting of titanium, silicon, tin, zirconium or aluminum. Preferred compounds correspond to the organometallic compounds defined above.
In case the liquid phase of the dispersion according to the invention also contains an organometallic compound, then such a compound is generally added by mixing a solution of the organometallic compound with a dispersion of titanium dioxide particles in the organic phase. Depending on the nature of the organometallic compound used, it is also possible to add additives such as cosolvents, surfactants or stabilizers during said mixing. The quality of the mixture can be improved by stirring the dispersion using ultrasound.
The solution of the organometallic compound added to the dispersion of titanium dioxide particles in the organic phase is generally a solution in the organic phase, which organic phase may be selected from the group consisting of ethanol, isopropanol, ethyl acetate and the like.
It is also possible to add organometallic compounds to the dispersion of titanium dioxide particles in pure form.
Said organometallic compounds may advantageously be stabilized products such as diethanolamine (DEA), • · • · · · ♦ · ··· · · • · ♦ · ♦ · · · · ······· · 9 9 9 9
29 acetylacetone derivatives such as ethyl acetoacetate, glycols and the like.
Said dispersion generally contains 5 to 90% by weight of organometallic compounds, expressed as metal oxides (MO), relative to the weight of titanium dioxide contained in the titanium dioxide particles and in the organometallic compounds expressed as metal oxides (ΜΟ).<sub>χ</sub>), preferably 15 to 80% and especially 20 to 75%.
As already mentioned above, in order to enhance the photocatalytic effect of the titanium dioxide coating, it is possible to add catalysts to the titanium dioxide, additives which make it possible to achieve better UV absorption or shift the absorption band to the visible light range, or alternatively metals which make doping oxide. titanium dioxide, inter alia, in order to increase the number of electron carriers.
According to a first alternative form, at least part of the titanium dioxide particles of the dispersion contain in their crystal lattice metal ions selected from the group consisting of iron, copper, ruthenium, molybdenum, bismuth, tantalum, niobium, cobalt, nickel or vanadium. The weight ratio of these metal ions to the weight of titanium dioxide may be 0.01 to 10%. These dispersions can be obtained by introducing metal ion salts during the preparation of titanium dioxide particles. In case the titanium dioxide particles are obtained by thermal hydrolysis of a titanium compound as described in patent application EP-A-0,335,773, then it is possible to add metal ions to the thermal hydrolysis medium so as to introduce said ions into the titanium dioxide crystal lattice. .
According to a second variant, at least part of the titanium dioxide particles of the dispersion are at least partially covered by a layer of metal salts or oxides, the metal being selected from the group consisting of iron, copper, ruthenium, cerium, molybdenum, bismuth, tantalum, niobium, cobalt, nickel, vanadium, tungsten, tin, zirconium, cadmium and zi • ·
<img file="CZ9800756A3_D0004.tif" />
nek. The weight ratio of these metals to the weight of titanium dioxide can vary between 0.01 and 20%. These dispersions can be obtained by precipitating metal salts on titanium dioxide particles before introduction into the organic medium. Thus, while the titanium dioxide particles are still in an aqueous medium after performing the wet preparative process, metal salts are introduced into said medium and precipitated so that at least a portion of the titanium dioxide particles are covered by the precipitate.
According to a third alternative form, at least part of the titanium dioxide particles of the dispersion are at least partially covered by a layer of metal selected from the group consisting of platinum, silver or rhodium. The weight ratio of these metals to the weight of titanium dioxide can vary between 0.01 and 5%. These dispersions can be obtained by reducing metal salts on titanium dioxide particles before introducing them into the organic medium. For example, when the titanium dioxide particles are still in the aqueous medium after performing the wet preparative process, the metal salts are introduced into the aqueous medium and then reduced so that at least a portion of the titanium dioxide particles are covered with the reduced metal.
According to a fourth alternative form, the dispersion contains, in addition to the titanium dioxide particles, additives in the form of particles based on metal compounds selected from the group consisting of cerium, cadmium, tin, tungsten, zinc or zirconium. These particles have a colloidal size, generally between 5 and 100 nm. Their content in the dispersion is between 0.1 and 20% by weight. As already mentioned above, the metal compounds can be oxides or sulphides, such as CeCl 2, SeCl 2, WO 2, ZnO, ZrO or CdSe S, where x and y represent a number between 0 and 1 and the sum of x + y = 1. the latter particles can be introduced into the dispersion by simply mixing with an aqueous dispersion of titanium dioxide particles resulting from the wet preparative process and then introducing all the particles in the aqueous phase into ···· · · ····· • · · · ····· • · · · · · ♦ · · · · · • · · · · · · · ··· ···· ·· ·· ·· ··
- 31 organic phases.
The dispersions according to the invention may have the characteristics of each of the four alternative forms mentioned or may have the characteristics of a combination of these alternative forms.
The invention finally relates to the use of the above-mentioned organic dispersions in the process for the preparation of the substrate according to the invention.
In the following part of the description, the invention will be described by means of specific examples of its embodiment, these examples being of an illustrative nature only and in no way limiting the scope of the invention, which is clearly defined by the wording of the claims.
In accordance with what is shown in an extremely schematic form in FIG. 1, all the following examples relate to the application of a so-called dirt-repellent coating 3.
essentially based on titanium dioxide on a substrate
Examples of embodiments of the invention
Example 1
Preparation of organic dispersion of titanium dioxide particles
According to the instructions given in patent application EP-A0,335,773, an aqueous dispersion of titanium dioxide particles is prepared in the presence of seed crystals.
Hydrolysis
To 394.7 g of a solution of titanium oxychloride with a concentration of 1.9 mol / kg is gradually added:
- 42.02 g of 36% hydrochloric acid,
4.73 g of citric acid,
-547.1 g of purified water,
- 11.36 g (0.2% by weight, based on the weight of TiCl4) germ • 4 ·· • · · · · · · 44 * 4
4 44 44444
4 44 4 44 44444 • 4 4 4 4 4 4 44
444 4444 44 4444 44
- 32 anatase crystals having a size between 5 and 6 nm.
The resulting mixture was heated to reflux and maintained at that temperature for 3 hours.
Isolation of titanium dioxide particles and their redispersion
The solution obtained is then filtered and the separated particles are washed with water until complete removal of chlorides is achieved. These particles are then redispersed at pH 1.5 (pH is adjusted by adding nitric acid) in such an amount as to achieve a solids content of 20% by weight.
An aqueous dispersion containing titanium dioxide particles having a diameter of 45 nm (measured by TEM) is obtained. X-ray analysis shows that 80% of the titanium dioxide particles are in anatase form and that the dispersion is based exclusively on titanium dioxide. The obtained particles are porous.
Dispersion of particles in an organic environment
100 parts by weight of the above dispersion are mixed with 100 parts by weight of ethylene glycol. The mixture is then heated to 80 DEG C. to remove water by distillation under reduced pressure (0.1 kPa), after which it is heated to 120 DEG C. to remove bound water.
A dispersion of titanium dioxide particles in ethylene glycol is obtained. The solids content is 20%. The particle size, measured in ethylene glycol by TEM, is 45 nm. The residual water content is 0.7% by weight, based on the titanium dioxide content.
Example 2
Preparation of an organic dispersion of niobium - doped titanium dioxide particles
The procedure described in Example 1 was repeated except that NbCl 2 was added to the hydrolysis medium in such an amount that the Nb / TiCl 2 molar ratio was 0.1%.
Examples 3 to 7
Application of the dispersions from Examples 1 and 2 by pyrolysis
The substrate £ is made of clear soda-lime silica glass and has a thickness of 6 mm and a square shape with a side of 50 cm. Optionally, there is a thin layer 2 between the coating 3 and the substrate 1.
The following Examples 3 to 7 relate to a coating 3 applied by a liquid phase pyrolysis technique. The application can be carried out continuously using a suitable distribution nozzle which is arranged transversely above the float glass strip at the outlet of the float glass bath chamber. In this case, the application was carried out discontinuously: the substrate 1, which has already been cut to the above-mentioned shape with the above dimensions, is first heated in an oven to 400-650 ° C and then passed at a constant speed along said slit spraying the respective solution.
Example 3
In this example, there is no possible layer 2. Coating 3 is applied using an organic dispersion A containing:
- a formulation containing organometallic titanium compounds and two organic solvents in the following percentages:
. 20% by weight of titanium diisopropoxydiacetylacetonate,. 20% by weight of titanium tetraoctylene glycolate, .40% by weight of ethyl acetate and .20% by weight of isopropanol, and • · ·· · • · ♦ * «· · · · ·· · · · · · · · · · · · · 9
9 9 9 9 9 9 99
999 9999 99 99 9999
- 34 - an organic dispersion of titanium dioxide particles according to Example 1, which is diluted and has the following characteristics:
. particle content by weight: 10%,. the particles have a size of 45 nm, measured using TEM,. crystallite size: 5 nm,. crystalline phase: more than 80% anatase,. liquid phase: ethylene glycol.
Said formulation and said organic dispersion are in such a ratio that the content of titanium dioxide particles in dispersion A is adjusted so as to obtain a content of 25% by weight of titanium dioxide derived from titanium dioxide particles in the coating already applied (weight of TiCl 4). (total weight of oxides in the coating, assuming that the decomposition of the organometallic compounds in dispersion A to oxides has taken place completely).
Once the temperature of the substrate in the furnace has reached the desired temperature, i.e. approximately 500 ° C, the substrate is passed in front of a nozzle spraying said mixture at ambient temperature and using compressed air.
A layer of titanium dioxide having a thickness of approximately 90 nm is obtained, this thickness being regulated by the speed of advance of the substrate along the nozzle or the temperature of said substrate. Said layer partially crystallizes in anatase form.
This coating contains both titanium dioxide originating from the decomposition of organometallic compounds and titanium dioxide in the titanium dioxide particles of the dispersion, the first titanium dioxide acting as a binder for the second titanium dioxide forming said particles. The obtained layer has excellent mechanical strength. The refractive index is 2.3.
Example 4
The procedure described in Example 3 is repeated, except for
<img file="CZ9800756A3_D0005.tif" />
characterized in that the substrate J comprises a thin layer 2 made of fluorine-doped tin dioxide (SnCl 2), this layer acting as a static and / or low-emitting layer and / or a layer which attenuates the color, in particular of the reflected light.
This layer was obtained by powder pyrolysis from dibutyltin difluoride (DBTF). It can also be obtained by liquid or vapor phase pyrolysis techniques known per se, which are described, for example, in patent application EP-A-0,648,196. In particular, it is possible to use a mixture of monobutyltin trichloride and a fluorinated precursor in the vapor phase, optionally in combination with a mild oxidizing agent of the H 2 O type.
This thin layer has a thickness of 73 nm, a refractive index of 1.9 and a surface resistance of 50 ohms per square unit.
This substrate is treated in the same way as in Example 3, after which it is assembled into a double glass assembly so that the coating 3 is located on the surface 1 (assembly with another substrate which is not coated, but which has the same character and dimensions as the substrate J). ), using a 12 mm air knife. The substrate has a color purity value in reflection (in the gold region) of 3.6% and in transmittance of 1.1%.
The substrate from Example 3 assembled in the same way has a color purity value (in the gold region) of 26% in reflection and 6.8% in transmittance.
The SnO: F sublayer has a beneficial effect on the colorimetry of the substrate in that its coloration appears more neutral in both reflection and transmittance (coloration is due to the presence of a titanium dioxide-based coating 3) and in that it has a relatively high refractive index. In addition, this layer limits the diffusion of alkali metals into the photocatalytic layer based on titanium dioxide. This improves the photocatalytic efficiency.
• *9 ·· ··*··· ······ *9 • · 9 9 9 9 999
9 9 9 9 9 9 99 9 9 ·
9 9 9 9 99 9 9
9999999 99 ·· 9 9 99
- 36 Despite the fact that the coating contains a large amount of particles, the distortion of the image in the view is less than 1%. This distortion of the view image is defined herein as the ratio of the transmission of the diffracted light to the total light transmission of the substrate at a wavelength of 560 nm.
Example 5
The procedure described in Example 3 is repeated, except that the substrate 1 comprises a thin layer 2 based on silicon oxycarbide, which acts as a barrier layer against the diffusion of alkali metals or as a layer which attenuates the reflection of light.
This layer is obtained by CVD from a mixture of SiH 2 and ethylene diluted with nitrogen as described in patent application EP-A-0,518,755. This layer is particularly effective against the tendency of alkali metals (Na<sup>+</sup>, K<sup>+</sup>) and alkaline earth metals 2+ (Ca) originating from the substrate J diffuse towards the coating 3.
This thin layer has a thickness of 50 nm and a refractive index of 1.75.
Since this layer, like SnCl 2, has a refractive index located between the refractive index of the substrate 1 (1.52) and the refractive index of the coating 3 (2,3), this layer makes it possible to reduce the color intensity of the substrate, both in the view , as well as in the reflection and reduce the total value of the light reflection R<sub>T</sub> of that substrate.
In addition, said silicon oxycarbide sublayer forms an effective barrier against the diffusion of alkali metals and thus achieves a remarkable improvement in the photocatalytic efficiency of the coating.
Example 6
The procedure described in Example 3 is repeated except that •
- 37, in that the coating 3 is applied using a dispersion B containing:
- a formulation based on silica ethoxide Si (OEt) diluted with ethanol to a concentration of 0.1 mol per liter of ethanol,
- an organic dispersion of titanium dioxide particles from Example 1.
Said formulation and said organic dispersion are used in such a ratio that the content of titanium dioxide particles in dispersion B is adjusted so as to achieve a titanium dioxide content in the coating of 80% by weight (weight of titanium dioxide derived from particles) / weight of titanium dioxide. particles + weight of silica obtained by decomposition of silica ethoxide Si (OEt) (it is assumed that the decomposition of said compound is complete).
Once the substrate 1 has reached the desired temperature in the furnace, i.e. approximately 200 ° C, it is passed around the nozzle spraying the dispersion B at room temperature using compressed air.
Thus, a mixed layer of titanium dioxide particles originating from the dispersion is obtained, which are bound both to each other and to the substrate by silica originating from the decomposition of the organometallic compound. The coating obtained has a thickness of approximately 50 nm and is 65% crystalline anatase.
The obtained layer has a high photocatalytic efficiency due to the high specific area formed by titanium dioxide particles (higher than 250 m 2 / g). In addition, the silica binder acts as an alkali metal barrier layer, which is particularly effective at the interface between the substrate and the titanium dioxide particles.
Finally, its refractive index is significantly lower than the index • 4 ····
- 38 ·· 9 · • · · · • ··· »» 9 »· · ♦ · · ·· 4« refraction of a non-specific layer based on titanium dioxide due to the presence of silica and due to its high porosity. The refractive index of this layer is thus lower than
1.6. As a result, the value of the light reflection R 1 of the substrate also decreases.
Example 7
The procedure described in Example 6 was repeated except that Dispersion B contained 0.1% of the niobium-doped titanium dioxide particles of Example 2.
The obtained coating has an even higher photocatalytic efficiency.
Example 8
Application of the dispersion from Example 1 by dip-coating
In this example, the so-called solgel technique using dip coating is used, the principle of which has been explained in Fig. 2. This technique consists in immersing the substrate 1 in a liquid solution 4 containing a dispersion and subsequently pulling the submerged substrate out of said solution 4 at a controlled speed using a motor means 5. and in fact to regulate the thickness of the applied coating. Subsequently, the coated substrate is subjected to a heat treatment in order to evaporate the solvent and decompose the metal oxide precursors.
Coating 3 is applied using dispersions A or B, which are described in Example 3, 6 or 7. An organic dispersion C containing also:
- a formulation based on titanium tetraoxide Ti (O-Bu) ^ stabilized with diethanolamine (DEA) in a molar ratio of 1: 1 and diluted with ethanol to reach a concentration
- 39 0,2 mol of titanium tetraoxide per liter of ethanol,
- a dispersion of titanium dioxide particles according to an example having the following characteristics:
. particle content by weight: 10%,. particles with a size of 45 nm, measured using TEM,. crystallite size: 5 nm,. crystalline phase: more than 80% anatase,. liquid phase: ethylene glycol.
Said formulation and said organic dispersion are used in such a mutual ratio that the content of titanium dioxide particles in dispersion C is adjusted so as to achieve a content of 80% by weight of titanium dioxide originating from titanium dioxide particles in the coating at the time the coating was applied (mass of titanium dioxide originating from the particles / total mass of oxides in the coating, assuming that the decomposition of organometallic compounds in dissociation C to oxides is complete).
After coating the substrates 1 containing thin layers 2 based on silicon oxycarbide by dipping in dispersions A, B or C, the substrates 1 are heated for 3 hours at 550 ° C with a gradual increase in temperature.
In all three cases, a coating 2 of well-crystallized titanium dioxide in anatase form is obtained on each of the substrate surfaces. The degrees of crystallization of anatase are comparable to the examples in which the pyrolysis coating technique was used, but the size of the crystallites is larger due to the prolonged heat treatment. This results in better photocatalytic efficiency.
The coating has a refractive index of not more than 1.8.
Example 9
Application of the dispersion from Example 1 by cellcoating • · · ·
In this example, a technique known as cell deposition is used, and the principle of this technique has been explained with reference to FIG. The essence of this technique is to form a narrow cavity defined by two substantially parallel surfaces 6 and 7 and two seals 8 and 9, at least one of said surfaces 6 or 1 being formed by the surface of the substrate J to be coated. Said cavity is then filled with dispersion 4 in a controlled manner so as to form a wettable meniscus, for example using a peristaltic pump 10, a thin layer of dispersion 4 adhering to the surface of the substrate 1 after the dispersion 4 has been discharged from the chamber.
Said chamber is then maintained for at least the time necessary to dry the adhering layer. Curing of this layer on the substrate is carried out by heat treatment, as in the previous examples.
Coating 3 is applied using dispersions A, B or C described in Examples 3, 6 and 8.
After coating the substrate J containing the thin layer 2 based on silicon oxycarbide by contact with dispersions A, B or C, the same heat treatment of the substrates 1 is carried out as in Example 8.
In all three cases, a coating 3 comparable to the coatings of Example 8 is obtained, but in this case only one side of the substrate is coated.
Example 10
Checking the properties of the obtained data
1) Wetting test
This test consists in applying a layer of organosilane to the test substrate, after which the substrate is exposed to the effect of: ··· · ······ ·· • · · · · · ····· · · 0 0 0 · · · · • · ·· · · 0 · · · · · 0 0 0 0 0 ··· • 00 0 ··· ·· ···· «·
- 41 UVA radiation to decompose said layer. Since the organosilane modifies the wetting properties, the measurement of the contact angle at the point of contact of the water with the substrate during irradiation indicates the degree of degradation of the grafted layer. The rate of disappearance of this layer is directly proportional to the photocatalytic efficiency of the substrate.
The grafted organosilane is trichlorosilane: octadecyltrichlorosilane (OTS). Grafting is performed by the dipping technique.
The test device consists of a rotary table rotating around 1 to 6 UVA lamps. The test specimens are placed on said turntable, with the side to be tested facing the UVA sources. Depending on the position of the sample on the rotary table and the number of switched on UVA lamps, each of the tested samples absorbs a radiation dose of 0.5 to 50 W / m<sup>2</sup>.
The time elapsed between individual measurements of the contact angle varies between 20 minutes and 3 hours, depending on the photocatalytic efficiency of the considered test sample. The measurement of the contact angle is performed using a goniometer.
The glass sample before irradiation has said contact angle approximately equal to 100 °. It is assumed that the organosilane layer is decomposed by irradiation when said contact angle is less than 20 °.
Each test sample is then characterized by the mean disappearance rate of the organosilane layer, expressed in nanometers per hour as the thickness of the deposited organosilane layer divided by the irradiation time after which said contact angle is less than 20 ° (organosilane layer disappearance time).
2)
Isobutane test • · · · · • · ·
<img file="CZ9800756A3_D0006.tif" />
The essence of this test is to control the degradation of gaseous isobutane brought into contact with the glass treated according to the invention.
The test glass and an amount of isobutane equal to 20% of the total reactor volume are introduced into the reactor.
The test device consists of a rotary table rotating around 1 to 6 low-pressure UVA lamps having an emission maximum between 300 and 400 nm. Reactors containing glass samples are placed on said rotary table, the glass surfaces to be tested facing the radiation source. Depending on the position of the samples on the rotary table and the number of switched-on lamps, each glass sample absorbs a dose of UVA radiation of up to 30 W / m.
Irradiation lasts for 8 to 22 hours.
The gradual photodecomposition of isobutane is monitored by a gas chromatograph monitoring the amount of 0<sub>2</sub>- This gradual decomposition of isobutane is expressed as a rate-decreasing constant2
O<sub>2</sub> and given in mol / h / cm 2.
3)
Palmitic acid test
The essence of this test is that a layer of palmitic acid is applied to the substrate to be tested and this substrate is then irradiated with UVA radiation in order to degrade the applied layer by photocatalysis.
A solution of palmitic acid in chloroform having a concentration of 8 g / l is sprayed on the test glass sample. The amount of palmitic acid stored on 30 cm of glass is about
1.5 mg. The glass samples thus treated are then introduced into a gas-tight reactor surrounded by six UV lamps having an emission maximum between 300 and 400 nm. The irradiated glass samples absorb a dose of 10 W / m. Irradiation lasts for 40 hours.
The glass samples are then removed from the reactor. In order to ·· * · · · · · ·· · • · · · ···· • ♦ · · · · · ···· · • · · · · ··· ········ ·· ·· · · Φ ·
- 43 determination of residual palmitic acid, the samples are washed with a solution of the acid in chloroform and the amount of palmitic acid in the solution thus obtained is then determined using liquid chromatography.
In this way, the time, expressed in minutes, required for the complete decomposition of 1.5 mg of palmitic acid is determined.
The decomposition of palmitic acid can also be observed visually by observing an increase in the fidelity of the image in the view of the glass, which occurs as the decomposition of the applied layer of palmitic acid occurs, assuming that the layer deteriorates said fidelity in proportion to its thickness. .
4) Anti-condensation test
The essence of this test is that the influence of photocatalysis and the structure of the coating (amount of hydroxyl groups, porosity, surface roughness) on the wettability of the substrate surface is monitored. If the surface of the substrate is photoreactive, are carbonaceous micropollutants, their? deposition on the surface of the coating occurs, continuously decomposed and the surface of the coating is thus hydrophilic and thus anti-condensing. It is also possible to make a quantitative determination by suddenly heating or blowing on a coated substrate which was originally stored in cold conditions, observing whether condensation is taking place and, if so, measuring the time required to the disappearance of the condensed product.
5) Contact angle test
The essence of this test is to determine the hydrophilicity and oleophilicity of the surface of the coating compared to the surface hydrophilicity and oleophilicity by measuring the contact angle of a water droplet and a dioctyl phthalate (DOP) droplet on their surfaces. The measurement is performed after the substrates have been left free for one week
<img file="CZ9800756A3_D0007.tif" />
- 44 air and thus exposed to natural light, and in the dark and after 20 minutes of exposure to UVA light.
Results of photocatalytic tests
<td>Background</td><td></td><td>Wetting</td><td>test</td><td>Isobutane</td><td>Acid test</td>
<td></td><td></td><td>at 1.8</td><td>W / m<sup>2</sup></td><td>test</td><td>linou palmi-</td>
<td></td><td></td><td>UVA</td><td></td><td>30 W / m<sup>2 * *</sup>UVA</td><td>tovou</td>
<td></td><td></td><td>(in nm / h)</td><td></td><td>(in mol / O ^ /</td><td>10 W / m<sup>2</sup> UVA</td>
<td></td><td></td><td></td><td></td><td>h / cn /)</td><td>(in min)</td>
<td>Example</td><td> 3</td><td> 0,1</td><td></td><td> 10’<sup>8</sup></td><td>more than 1000</td>
<td>Example</td><td> 4</td><td> 0,3</td><td></td><td>2 x 10 "<sup>8</sup></td><td>more than 1000</td>
<td>Example</td><td> 5</td><td> 3</td><td></td><td> 10’<sup>7</sup></td><td> 800</td>
<td>Example</td><td> 6</td><td> 4</td><td></td><td>'Ο '<sup>7</sup></td><td> 730</td>
<td>Example</td><td> 7</td><td> 6</td><td></td><td> 10<sup>7</sup></td><td> 620</td>
Dispersion A 5 10 <sup>7</sup> 660
Examples Dispersion B 10 2 x 10? 390 and 9 ...............................................
Dispersion C 20 5 x 10 <sup>7</sup> 250
Test results 4: no condensation was detected for all substrates according to Examples up to 9.
Test results 5: for all substrates according to Examples up to 9, the contact angle of the water droplet and dioctyl phthalate is less than 5 ° after 20 minutes of exposure to UVA radiation.
Contents9
10 sheets
Sheet 1 Sheet 2 Sheet 3 Sheet 4 Sheet 5 Sheet 6 Sheet 7 Sheet 8 Sheet 9 Sheet 10
29 members in 17 offices
Priority claims2
| Document | Office | Kind | Date |
|---|---|---|---|
| 9510936 | France | A | |
| 9510838 | France | A |
Members29
| Document | Office | Kind | |
|---|---|---|---|
| WO9710185A1 | World Intellectual Property Organization (WIPO) | A1 | |
| FR2738812A1 | France | A1 | |
| FR2738836A1 | France | A1 | |
| AU6992796A | Australia | A | |
| FR2738812B1 | France | B1 | |
| TR199800474T1 | Türkiye | T1 | |
| EP0850203A1 | European Patent Office (EPO) | A1 | |
| FR2738836B1 | France | B1 | |
| MX9802017A | Mexico | A | |
| PL325526A1 | Poland | A1 | |
| CZ75698A3This record | Czechia | A3 | |
| KR19990044670A | Republic of Korea | A | |
| JPH11512336A | Japan | A | |
| BR9610289A | Brazil | A | |
| US6037289A | United States of America | A | |
| EP0850203B1 | European Patent Office (EPO) | B1 | |
| DK0850203T3 | Denmark | T3 | |
| AT198733T | Austria | T | |
| ATE198733T1 | Austria | T1 | |
| DE69611618D1 | Germany | D1 | |
| ES2155941T3 | Spain | T3 | |
| PT850203E | Portugal | E | |
| DE69611618T2 | Germany | T2 | |
| US6362121B1 | United States of America | B1 | |
| KR100377606B1 | Republic of Korea | B1 | |
| CZ297518B6 | Czechia | B6 | |
| EP0850203B2 | European Patent Office (EPO) | B2 | |
| ES2155941T5 | Spain | T5 | |
| DE69611618T3 | Germany | T3 |
2 legal events, as the office reported them to INPADOC
Over the term
Point at a mark for the eventEvents
| Event | Code | |
|---|---|---|
| Patent lapsed due to non-payment of feeLapsedMM4A | MM4A | |
| Pending as of 2000-06-30 in czech republicPD00 | PD00 |
Numbers
- Application
- 75698
Titles2
- Czech
- Podklad s fotokatalytickým povlakem na bázi oxidu titaničitého a organické disperze na bázi oxidu titaničitého
- English
- BASE WITH PHOTOCATALYTIC COATING BASED ON TITANIUM DIOXIDE AND ORGAN IC DISPERSION BASED ON TITANIUM DIOXIDE
Classification
- CPC, 39
- C23C30/00
- C03C17/00
- B82Y30/00
- C01G23/047
- C01P2002/02
- C01P2002/50
- C01P2004/64
- C01P2004/86
- C01P2006/60
- C01P2006/82
- C03C8/20
- C03C17/007
- C03C17/008
- C03C17/2456
- C03C17/256
- C03C2217/212
- C03C2217/29
- C03C2217/45
- C03C2217/477
- C03C2217/71
- C04B41/5041
- C04B41/52
- C09D1/00
- C09D17/008
- C23C18/1216
- C23C18/1225
- C23C18/1245
- C23C18/1254
- C23C18/1258
- C23C18/127
- C23C18/1295
- C23C26/00
- Y10S502/522
- B01J2235/15
- B01J35/77
- B01J35/36
- B01J35/395
- B01J2235/30
- Y02T50/60
- IPC, 15
- B01J35 36
- B01J35 77
- C01G23 047
- C03C8 20
- C03C17 00
- C03C17 245
- C03C17 25
- C04B41 50
- C04B41 52
- C09D1 00
- C09D5 00
- C09D17 00
- C23C18 12
- C23C26 00
- C23C30 00