Titania coatings.
Abstract
Photocatalytic titania coatings deposited by a CVD process using an organic titanium compound and an oxygen containing organic compound exhibit improved properties. They are more durable and smoother than existing coating and are less susceptible to scratching. The preferred titanium compound is titanium isopropoxide and the preferred organic compound is ethyl acetate.

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14 claims: 9 independent, 5 dependent
- 1REIVINDICACIONES 1. Un proceso de depósito de vapor químico, para el depósito de un recubrimiento activo 5 fotocatalíticamente, que comprende el óxido de titanio sobre la superficie de un substrato, este proceso se caracteriza porque comprende poner en contacto esa superficie con un vapor que contiene el tetraetóxido de titanio o el tetrapropóxido de titanio, para formar un R - C(0) - 0 - CO(XX') - C(YY') - R' 15 en la cual R y R', que pueden ser iguales o diferentes, representan átomos de hidrógeno o un grupo alquilo que comprende de 1 a 10 átomos de carbono, X, X', Y y Y', que pueden ser iguales o diferentes. representan átomos de hidrógeno o grupos alquilo, que 20 comprenden de 1 a 4 átomos de carbono, con la condición que al menos uno de Y o Y' representa un átomo de hidrógeno.
- 23. Un proceso, de acuerdo con la reivindicación 2, caracterizado porque el éster de carboxilato es un éster en que R es un grupo alquilo, que comprende de 1 a
- 34 átomos de carbono.
- 45 4. Un proceso, de acuerdo con la reivindicación 3, caracterizado porque el grupo alquilo es un grupo etilo. 5. Un proceso, de acuerdo con la reivindicación 3, caracterizado porque el éster de carboxilato se 10 selecciona del grupo que consta del formato de etilo, acetato de etilo, propionato de etilo, butirato de etilo, formato de n-propilo, acetato de n-propilo, propionato de n-propilo, butirato en-propilo, formato de isopropilo, acetato de isopropilo, propionato de 15 isopropilo, butirato de isopropilo, formato de nbutilo, acetato de n-butilo, acetato de sec.-butilo y acetato de t-butilo.
- 56. Un proceso, de acuerdo con la reivindicación 5, caracterizado porque el éster de carboxilato es el 20 acetato de etilo.
- 67. Un proceso, de acuerdo con cualquiera de las reivindicaciones precedentes, caracterizado porque el substrato está a una temperatura en el intervalo de 400 a 800°C.
- 78. Un proceso, de acuerdo con cualquiera de las reivindicaciones precedentes, caracterizado porque que 5 el substrato está a una temperatura de 610 a 720°C.
- 89. Un proceso, de acuerdo con cualquiera de las reivindicaciones precedentes, caracterizado porque que el substrato es una banda de vidrio, producida durante un proceso de producción de vidrio flotante.
- 910 10. Un proceso, de acuerdo con la reivindicación 9, caracterizado porque el depósito toma lugar dentro del baño de flotación.
- 1011. Un substrato activo fotocatalíticamente, que tiene un recubrimiento de óxido de titanio, sobre al menos una 15 de sus superficies, caracterizado porque la superficie recubierta exhibe una actividad fotocatalítica de al menos el 50% (expresada como la reducción del porcentaje de las crestas de absorción integradas, que corresponden a una película delgada del ácido 20 esteárico, producida por la irradiación UVA con una intensidad de 0.7 w/m 2 , por un período de 30 minutos) y no se afecta por la inmersión de una solución 1 molar de hidróxido de sodio, a 75 °C, por un período de al menos 6 horas.
- 1112. Un substrato activo fotocatalíticamente, que tiene un recubrimiento de dióxido de titanio, sobre al menos una 5 de sus superficies, caracterizado porque la superficie recubierta tiene un valor de Ra menor de 2 nm, y una actividad fotocatalítica de cuando menos el 50% (expresada como la reducción del porcentaje de las crestas de absorción integradas, que corresponden a una 10 película delegada de ácido esteárico, producida por la irradiación UVA, con una intensidad de 32 W/m 2 , por un período de 30 minutos).
- 1213. Un substrato activo fotocatalíticamente, que tiene un recubrimiento de dióxido de titanio, sobre al menos una 15 de sus superficies, caracterizado porque el recubrimiento es cristalino y tiene un valor de Ra menor de 2 nm.
- 1314. Un substrato activo fotocatalíticamente, que tiene un recubrimiento de óxido de titanio, sobre al menos una 20 de sus superficies, caracterizado porque la superficie recubierta exhibe una actividad fotocatalítica de cuando menos el 80% (expresada como la reducción del porcentaje de las crestas de absorción integradas, que corresponden a una película delgada de ácido esteárico, producida por la irradiación de UVA, con una intensidad de 0.76 W/m 2 , durante un período de 30 minutos) y una 16. Un substrato de vidrio, de acuerdo con cualquiera de 10 las reivindicaciones 10 a 14, caracterizado porque la capa de dióxido de titanio tiene un espesor de 10 nm a 40 nm. 18. Un substrato de vidrio, de acuerdo con cualquiera de las reivindicaciones 10 a 17, caracterizado porque comprende una capa de bloqueo de un metal alcalino, entre el vidrio y el recubrimiento de dióxido de 20 titanio. hasta 20 nm. 5 20. Un substrato de vidrio, de acuerdo con cualquiera de las reivindicaciones 10 a 19, caracterizado porque el substrato permanece fotoactivo, después de realizar 200 ciclos de la prueba de reciclado de humedad. 21. Un substrato de vidrio, de acuerdo con cualquiera de 10 las reivindicaciones 10 a 20, caracterizado porque el recubrimiento no se afecta por la inmersión en una solución 1M de hidróxido de sodio, 75°C, durante un período de seis horas. 22. Un substrato de vidrio, de acuerdo con cualquiera de
- 1415 las reivindicaciones 10 a 21, caracterizado porque tiene una resistencia a raspaduras del recubrimiento, de modo que una prueba de pasador y disco, bajo una carga de 3 Nm, no produce un raspado continuo sobre la superficie recubierta. 23. Un substrato de vidrio, de acuerdo con cualquiera de las reivindicaciones 10 a 22, caracterizado porque el contenido de carbón del recubrimiento es menor del 10%.
Independent claims14
225 paragraphs in 9 sections, as filed
(54) Title: COATINGS OF TITANIA. (54) Title: TITANIA COATING S.
(57) Summary
Photocatalytic titania (titanium dioxide) coatings, deposited by a chemical vapor deposition (CVD) process, using an organic titanium compound and an organic oxygen-containing compound, exhibit improved properties. These coatings are more durable and smoother than existing coatings and are less susceptible to scratches. The preferred titanium compound is titanium isopropoxide and the preferred organic compound is ethyl acetate.
(57) Abstract
Photocatalytlc titania coatlngs deposlted by a CVD process using an organlc tltanlum compound and an oxygen containing organlc compound exhlblt ¡mproved properties. They are more durable and smoother than existing coatlng and are less susceptible to scratchlng. The preferred tltanlum compound ¡s tltanlum ¡sopropoxlde and the preferred organlc compound ¡s ethyl acétate.
(12) INTERNATIONAL APPLICATION PUBLIS HED ÜNDER THE PATENT COOPERATION TREATY (PCT) (19) World InteDectual Property Organization International Bureau (43) International PubUcation Date 7 October 2004 (07.10.2004)
<img file="MXPA05009815A_D0001.tif" />
PCT (10) International Publication Number
WO 2004/085701 Al (51) International Patent Classiflcation<sup>7</sup>: C23C16/40,
C03C 17/245 (21) International Application Number:
PCT/GB2004/001310 (22) International Filing Date: 25 March 2004 (25.03.2004) (25) Filing Language: English (81) Designated States (unless otherwise indicated, for every kind of national protection available): AE, AG, AL, AM, AT, AU, AZ, BA, BB, BG, BR, BW, BY, BZ, CA, CH, CN, CO, CR, CU, CZ, DE, DK, DM, DZ, EC, EE, EG, ES, H, GB, GD, GE, GH, GM, HR, HU, ID, IL, IN, IS, JP, KE, KG, KP, KR, KZ, LC, LK, LR, LS, LT, LU, LV, MA, MD, MG, MK, MN, MW, MX, MZ, NA, NI, NO, NZ, OM, PG, PH, PL, PT, RO, RU, SC, SD, SE, SG, SK, SL, S Y, TJ, TM, TN, TR, TT, TZ, UA, UG, US, UZ, VC, YN, YU, ZA, ZM, ZW.
) (26) Publication Language: English (30) PriorityData:
0306797.2 25 March 2003 (25.03.2003) GB _ (71) Applicant (for ad designated States except US)’. PILKINGTON PLC [GB/GB}; Piescot Road, SL Helens, = Merseyside WA10 3TT (GB).
= (72) Inventor; and
ΞΞ (75) Inventor/Applicant (for US only): YE, Liang [GB/GB];
Norwood Crescent, Southport, Merseyside PR9 7DU <sup>ggs</sup> (74) Agente: HALLIWELL, Anthony, Charles et al.; Group = Intellectual Property Dept, Pilkington European Technical
SS Centre, Pilkington pie, Hall Lañe, Lathom, Ormskirk, Lansag cashire L40 5UF (GB).
(84) Designated States (unless otherwise indicated, for every kind of regional protection available): ARIPO (BW, GH, GM, KE, LS, MW, MZ, SD, SL, SZ, TZ, UG, ZM, ZW), Eurasian (AM, AZ, B Y, KG, KZ, MD, RU, TJ, TM), European (AT, BE, BG, CH, CY, CZ, DE, DK, EE, ES, H, FR, GB, GR, HU, ΙΕ, IT, LU, MC, NL, PL, PT, RO, SE, SI, SK, TR), OAPI (BF, BJ, CF, CG, Cl, CM, GA, GN, GQ, GW, ML, MR, NE, SN, TD, TG).
Pubtished:
— with intemational search report — befare the expiration of the time limit for amending the claims and to be republisked in the event of receipt of amendments
For two-letter codes and other abbreviations, referto the Guidance Notes on Codes and Abbreviations appearing at the beginning ofeach regular issue ofthe PCT Gazette.
= (54) Title: TITANIA COATENGS í
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(57) Abstract: Photocatalytic titania coatings deposited by a CVD process using an organic titanium compound and an oxygen containing organic compound exhibit improved properties. They are more durable and smoother than existing coating and are less susceptible to scratching. The preferred titanium compound is titanium isopropoxide and the prefeired organic compound is ethyl acétate.
RECUBRIMIENTOS DE TITANIA <
The invention relates to substrates having a coating of titania (titanium dioxide) on at least one surface and to processes for depositing the coatings of titania on the surface of a substrate. In preferred embodiments, the substrate is a sheet of glass.
Titania coatings are known to possess photocatalytic self-cleaning properties. These 10 titania coated substrates and the processes for producing such coated substrates have been described, for example, in EPA Publications 901991, WO 97/07069, WO 97/10186, WO 98/41480 and WO 00/75087. Coatings can be deposited by a variety of techniques, including sol-gel processes, spray pyrolysis processes, electronic magnetron vacuum deposition processes, and chemical vapor deposition processes.
We have now discovered novel chemical vapor deposition processes (hereafter, by conv (20 CVD processes) leading to the production of coated substrates having improved properties. In a preferred embodiment, these CVD processes can be integrated with a floating glass production process, to produce novel coated glass sheets in an efficient and economical manner. These processes comprise bringing a vapor, comprising a titanium precursor, into contact with the hot glass strip at a point in the process where the strip temperature is sufficient to result in the formation of the desired titania coating.
A variety of titanium precursors have been proposed for use in CVD processes for titania deposition. Examples include inorganic compounds, such as titanium tetrachloride and organic titanium compounds, such as titanium tetra-isoepoxide and titanium tetraethoxide. Those precursors, which do not contain oxygen as part of the molecular structure, They are normally used in the presence of oxygen or an oxygen-containing compound. Publication WO 00/75087 describes a CVD process, which uses titanium tetrachloride together with ethyl acetate. These precursors, which do not contain oxygen as part of their molecular structure, can be used with or without an additional source of oxygen.
WO 00/75087 describes a CVD process which uses titanium tetraethoxide in the absence of any additional sources of oxygen. Publication 902992 describes a CVD process which uses titanium tetra-isopropoxide and titanium tetraepoxide in combination with oxygen gas.
There is a current need for a process which deposits the titania coating of the desired quality, and in a cost effective manner.
We have now discovered that a CVD process for the deposition of a titanium oxide coating, which uses a vapor comprising e an organic titanium compound and an oxygen-containing organic compound, is more efficient than known processes and can produce a titania coating, which exhibits improved properties. This coating can be smoother, it can be more durable and it can be less susceptible to deactivation, when it is deposited directly on a glass surface.
Accordingly, from a first aspect of this invention there is provided a process for the deposition of a photocatalytically active coating, which includes a titanium oxide on the surface of a substrate, this process comprises contacting a surface of the substrate with a fluid mixture including an organic titanium compound and an organic oxygen-containing compound, at a temperature which is high enough to form a titanium oxide coating.
The organic titanium compound is preferably an oxygen-containing compound com or part of the molecular structure and, more preferably, one that comprises at least one oxygen atom, which is attached to a titanium atom.
Examples of preferred titanium compounds are titanium alkoxides, such as titanium tetra-isopropoxide and titanium tetra-ethoxide.
The oxygen-containing organic compound is preferably an ester and, more preferably, is a carboxylate ester. Preferred esters are compounds having the formula:
R - C (0) - 0 - C (XX ') - C {YY') - R 'in which R and R', which may be the same or different, represent hydrogen atoms or an alkyl group comprising from 1 to 10 carbon atoms, X, X ', Y and Y<sup>1</sup>, which may be the same or different, represent hydrogen atoms or alkyl groups, comprising from 1 to 4 carbon atoms, provided that at least one of Y or Y<sup>1</sup> represent a hydrogen atom. Preferably R and R<sup>1</sup> represent atoms hydrogen or alkyl groups, containing 1 to 4 carbon atoms.
Examples of esters, which are preferred for use in the processes of this invention, include ethyl format, ethyl acetate, ethyl propionate, ethyl butyrate, n-propyl format, n-propyl acetate, n propionate -propyl, n-propyl butyrate, isopropyl format, isopropyl acetate, isopropyl propionate, isopropyl butyrate, n-butyl format, n10 butyl acetate, secondary butyl acetate, and tertiary butyl acetate.
The most preferred esters for use in this invention are ethyl, ethyl propionate, and in particular ethyl acetate.
A mixture of two or more organic compounds that contain oxygen can be used. The fluid mixture may also comprise a smaller proportion of the gaseous oxygen. Introducing higher proportions of oxygen into the fluid mixture is less preferred and may be tar in the deposit of coatings that have inferior properties. The fluid mixture will further normally comprise at least one inert carrier gas, into which the active components are entrained. The most common carrier gases are nitrogen and helium. The organic titanium compound and the organic oxygen-containing compound will generally comprise 0.1 to 1.0% by volume of the fluid mixture. The molar ratio of the oxygen-containing organic compound to the organic titanium compound will preferably be in the range of 0.5: 1.0 to 1.2: 1.0, more preferably in the range of 0.8 to 1.0 to 1.0:
1.0.
The substance is preferably a glass substrate. The glass may conveniently be a sheet of glass, and in particular it may be in the form of a continuous strip of glass, produced by the floating glass process. In a preferred embodiment, the deposit is carried out online, during a production process floating glass.
<td></td><td>The fluid mixture must be in contact with</td><td>he</td>
<td>substrate</td><td>at an elevated temperature. usually,</td><td>he</td>
<td>substrate</td><td>must be heated to a temperature in</td><td>he</td>
<td>interval</td><td colspan="2">from 400 to 800 ° C. Band temperature</td>
Continuous, in the float glass production process, ranges from about 1100 ° C in the hot end of the flotation bath, to 600 ° C in the cold end and from about 580 ° C to 200 ° C in the tempering furnace of glass. The processes of the invention can be carried out at a suitable point in the flotation bath, in the gap between the flotation bath and the glass tempering furnace or at the hottest end of the glass tempering furnace. The processes of this invention are preferably carried out by bringing the fluid mixture into contact with the substrate, when or that substrate is at a temperature of
610 ° C to 720 ° C, preferably in the range of 625 ° C to
700 ° C, and more preferably in the range of 625 ° C to
650 ° C. When these preferred processes are carried out as part of the floating glass production process, they will be carried out at a point which is within the flotation bath.
The flow rate of the fluid mixture must be adjusted to provide the desired coating. The optimal rate is affected by a variety of factors, including the nature and temperature of the substrate, the surface area of the substrate, the linear speed of the glass strip in the floating glass production process, and the rate at which the gas Exhaust is removed from the coating apparatus.
In the case of a glass substrate, the titania coating can be deposited on the surface of the glass itself, or one or more sub-reco Sprouts can be deposited on the glass, before the deposition of the titania layer. In a preferred embodiment of this invention, the titania coating is deposited directly onto the surface of the glass strip, during the flotation glass production process. Depositing directly on the glass surface can lead to increased growth of titania, compared to depositing on a sub-coating.
A multi-layer coating can be conveniently applied by arranging two or more coating apparatus in sequence along the glass strip.
A particular type of undercoat known to be advantageous is an alkali metal blocking layer. It is known that the migration of sodium ions is from the uncoated glass substrate within a layer of photocatalytic titania, deposited on that substrate, can reduce photocatalytic activity. Using Boq Layers The use of sodium ions has been described, for example, in WO 98/51480 and WO 00/75087. Another type of undercoating uses an alkali metal blocking layer over a metal oxide coating, such as a tin oxide, to create a color suppressing effect.
The alkali metal blocking sub-layer may comprise a metal oxide, but preferably, the alkali metal blocking layer is a layer of a silicon oxide. This silicon oxide can be silica, that is, it can have the stoichiometry of SiO<sub>2</sub> or it may comprise other elements, such as carbon (such layers being commonly referred to as silicon oxycarbide, and deposited, for example, as described in GB 2199848) or nitrogen (such layers are commonly referred to as oxynitride). silicon).
The alkali metal blocking subcoat must be thick enough to reduce or block migration s alkali metal ions in the titania layer to the desired degree. The layer should also preferably not have a significant effect on the optical properties of the glass. Thinner layers have less effect and, as a result, the thickness of the undercoat can be selected to provide a compromise between these two preferred targets. Typically, the sub20 coating (when present) will be 30 to 70 nm thick, more preferably 40 to 60 nm.
The titania coatings, which are produced by the processes of this invention, comprise a dense layer of titanium dioxide, which prevents the migration of sodium from reducing photoactivity. The thickness of the coating, which is required in order to prevent the migration of sodium ions from the glass to the surface of the coating and to reduce the photocatalytic activity of the coating, may be reduced or preferably eliminated. When a subcoat is present With sodium ion blocking, the thickness of the blocking layer may also be reduced, compared to that used under titania coatings deposited by other CVD processes. Where the titania coating is deposited directly on the glass surface, the thickness of that coating is preferably in the range of 100A to 400A, preferably in the range of 150A to 350A and more preferably, in the range of 100 Á at 200 Á. When the titania coating is deposited on top of an alkali metal blocking subcoat of the titania coating, it is preferably in the range of 100A to 200A.
The glass substrate will normally be clear, soda-lime float glass. The glass substrate can also be a tinted glass, for example a virium in which a colorant, such as iron oxide, cobalt oxide, nickel oxide, selenium oxide or ox gone from titanium, it has been added. These tinted glasses are readily available in a variety of shades, such as gray , bronze, blue, and green.
The processes of this invention are advantageous in that they deposit the titania coating more consistently than previously known processes.
They can be operated for long periods without any deterioration in product quality and this improves the economy of the processes. In addition, the coating exhibits a more neutral color, as measured by the CIELAB Color System (Illuminant C). Analysis shows that the coating contains fewer carbon atoms than previously found and this appears to produce the most neutral coloration. Coatings comprising less than 10% carbon, form a preferred aspect of this invention.
The coated substrates of this invention can exhibit novel and useful properties. In particular the coating Titania powder may consist substantially or essentially of crystalline titania, the coatings of which have a smoothness comparable to that of amorphous titania. Such products are advantageous in that they exhibit the high degree of photocatalytic activity, which is associated with crystalline titania, while the smoothness of the surface reduces the tendency of dirt or other contaminants to stick to the surface and enables any dirt adhesion to the surface to be washed and removed more easily.
The preferred coated substrate of this invention has a titania coating on at least one of its surfaces, said coating is crystalline and has a roughness value Ra less than 3.0 nm, more preferably less than 1.5 nm and especially preferred, less than 1 nm.
Such substrates are believed to be novel and comprise a further aspect of the invention.
The coatings of this invention are characterized ad also because the average grain diameter, seen in plan (which can be measured using a microscope
High resolution SEM) is less than 2 0nm, preferably less than 15nm and more preferably less than 10nm. Smaller grain sizes appear to be associated with a structure
0 column type grain and in the preferred coatings of this invention, the titania grains will have a diameter to height ratio (which can be determined using the XTEM microscope) less than 0.6 and preferably less than
0.4. The coatings of this invention have a relatively uniform particle size, which can be seen by visual inspection of the SEM microscope.
The invention enables thinner titania coatings to be produced, which have a lower reflection, preferably 12% or less, while retaining photoactivity and durability. Applicants associate these enhanced properties with the structure d the dense and small grain of the coatings.
Photocatalytic activity, for the purposes of this specification, is determined by measuring the percent reduction of the integrated absorption ridges, which correspond to the CH expansions of a thin film of stearic acid, which is produced by illumination by light of a UVA lamp, which has an intensity of about 0.76 w / m<sup>2</sup>/ nm at the surface of the substrate and a peak wavelength of 340 nm for a period of 30 minutes. The stearic acid film can be formed by rotationally molding a solution of the stearic acid in methanol on the surface of the substrate.
Clean or freshly prepared glass has a hydrophilic surface (a static contact angle of water, less than about 40! Indicates a hydrophilic surface) but organic contaminants quickly adhere to the surface, increasing this contact angle. A particular benefit of the coated substrates (and especially the coated glass) of the present invention is that they have a lower contact angle when produced, but more importantly when the coated surface is fouled by irradiation of organic contaminants from the Surface coated by UV light of correct wavelength, will reduce contact angle, reducing or destroying these pollutants. A further advantage is that the water will spread on the surface with a low contact angle, reducing the distracting effect of the water droplets on the surface (for example from the rain) and tending to wash and limit any dirt or other contaminants that have not been destroyed by photocatalytic activity on the surface. The static contact angle of water is the angle subtended by the menisci of the water droplet on a glass surface and can be determined in known ways by measuring the diameter ro of the water droplet of known volume, on the glass surface and calculated using an iterative procedure.
Preferably the coated substrate has a fog of not more than 1% and preferably not more than
0.5, or even 0.2%, which is beneficial because it allows clarity of vision through a clear coated substrate.
In preferred embodiments, the coated surface of the substrate is more durable than existing titanium coated self-cleaning glasses. Preferably, the coated surface remains photocatalytically active after it has been subjected to 500 strokes of the European standard abrasion test, and more preferably, the coated surface remains photocatalytically active after it has been subjected to 1000 strokes of the European standard abrasion test.
This is advantageous, because the self-cleaning coated substrates of the present invention, They will often be used on the coated surface exposed to the outside (for example, glass coated with the glass coated surface as the external surface of a window), where the coating is vulnerable to abrasive.
The European standard abrasion test, refers to the abrasion test described in the European Standard BS EN
1097 Part 2 (1999) and comprises the reciprocal of a felt pad at a set speed and pressure on the sample surface.
In the present specification, a coated substrate is considered to remain catalytically photo5 active if, after having undergone the European Abrasion Test, UV light irradiation (eg peak wavelength 351 nm) reduces the contact angle of the static water below 15 °. To achieve this contact angle, after abrasion of the coated substrate, it will usually take less than 48 hours of irradiation at an intensity of alr about 0.78 W / m<sup>2</sup>/ nm, on the surface of the coated substrate.
Preferably, the fogging of the coated substrate is 2% or less, after undergoing said European abrasion test.
Durable coated substrates, in accordance with the present invention, are also durable to moisture cycles (which are intended to have an effect similar to the environment). Thus, in preferred embodiments of the invention, the coated surface of the substrate is durable to moisture cycles, compared to the coated surface that remains photo-catalytically active, after the coated substrate has undergone 200 cycles of testing. moisture cycling. In this specification, the moisture cycling test refers to a test in which the coating is subjected to a temperature cycle of
35 ° C, at 75 ° C to 35 ° C in 6 hours, at about 100% relative humidity. The coated substrate is considered era remains photocatalytically active if, after testing, UV irradiation reduces the contact angle of static water to below 15%.
The durability of the coatings can also be evaluated by means of a sodium hydroxide etching test. A sample of the coated glass is immersed in a sodium hydroxide solution M, which is kept at a temperature of 75 ° C. The test is terminated at the point when the coating can be limited from the glass surface or when the optical properties of the glass are significantly impaired. Coated glasses, according to the processes of this invention, are not affected after six hours of immersion and, in preferred embodiments, are not affected after ten hours of immersion.
The coating of this invention also exhibits improved scratch resistance. Photoactive coatings are necessarily exposed on one side of the glass and the s scratches during the process or after installation leave a cosmetically unacceptable mark on the glass. Scratch resistance is measured using a disk pin test, which uses a variable load on the pin. The scratch resistance was measured as the minimum load which results in continuous scratching on the surface. The coatings of this invention were not scraped by a load of 3Nm and, in preferred embodiments, were not scraped by loads of 5Nm or even 10Nm.
Coated substrates, in accordance with the present invention, have uses in many areas, for example, as window panes, including a multi-pane unit comprising a first sheet of glass of a coated substrate in an opposite spaced relationship, to a second sheet of glass or, when the coated substrate is coated glass, such as laminated glass, comprising a first glass layer of this coated glass, or na polymer interlayer (of, for example, polyvinylbutyral) and a second layer of glass.
In addition to uses on self-cleaning substrates (especially self-cleaning window glass), the coated substrates of the present invention may also be useful in reducing the concentration of air pollutants. For example, coated glass, under the irradiation of light wavelengths
UV (which includes the wavelengths of UV light present in sunlight) can destroy atmospheric pollutants, for example, oxides of nitrogen, ozone, and organic pollutants adsorbed on the coated surface of the glass. This use is particularly advantageous in accumulation in open areas (for example, on city streets), where the concentration of organic pollutants can be relatively high (especially in strong sunlight), but where the available surface area glass is also It is relatively high. Alternatively, coated glass (with the coated surface inside) can be used to reduce the concentration of air pollutants inside buildings, especially office buildings, which have a relatively high concentration of air pollutants.
The invention is illustrated, but not limited, by the following drawings.
Figure 1 illustrates an apparatus for in-line chemical vapor deposition of coatings according to the invention.
The coating layers can be applied in line on the glass substrate by the chemical vapor deposit, during the glass manufacturing process. Figure 1 illustrates an apparatus, generally indicated at 10, useful for in-line production of the coated glass article of the present invention, comprising a flotation section 11, a glass furnace 12, and a righting section 13. The section float ion 11 has a bottom
14, containing a molten tin bath 15, a roof 16, side walls (not shown) and end walls 17, which together form a seal, so that an enclosed area 18 is provided, in which the non-oxidizing atmosphere is maintains to prevent oxidation of the tin bath 15. During the operation of the apparatus 10, the molten glass 9 melts in a crucible 20, and flows from there, under a metering wall 21, then down onto the surface of the tin bath 15, which forms a band of floating glass 37, which is removed by the lifting rollers 22 and is transported through the glass furnace 12, and then through the section 13 of
0 cooling.
A non-oxidizing atmosphere is maintained in the flotation section, introducing a suitable gas, such as, for example, that comprising nitrogen and 2% by volume of hydrogen, in zone 18, through ducts 23, which are connected operably to a collector 24. Non-oxidizing gas is introduced into zone 18 from lines 23 at a rate sufficient to compensate for gas losses (some of the oxidizing atmosphere leaves zone 18 flowing under end walls 17) and to maintain a slight positive pressure above of environmental pressure. Tin bath 15 and enclosed area 18 are fueled by radiant heat, directed downward from the heaters 25. Heat zone 18 is generally maintained at a temperature of approximately
721 at 760 ° C. The atmosphere in the glass furnace 12 is typically air and the cooling section 13 is not enclosed. The ambient air is blown onto the glass by fans 26.
The apparatus 10 also includes the covering elements 27, 28, 29 and 30, located in series in the floating zone above the floating glass bands 37.
The precursor gas mixtures for the individual layers of the coating are supplied to the elements of
0 coating, which, in turn, direct the precursor gaseous mixtures to the hot surface of the floating glass strip 37. The temperature of the floating glass strip 37 is highest at the location of the lining element 27, closest to the crucible 20, and lowest at the location of the lining element 30 closest to the glass furnace 12.
The invention is further illustrated by the following examples, in which the coatings are applied by depositing laminar flow chemical vapor, in the floating bath, on a moving strip of floating glass, during the glass production process. In the examples, one or two coating layers are applied to the glass strip.
All gas volumes are measured at a standard temperature and pressure, unless otherwise noted. The thickness values of the layers are determined using the electron microscopy of e Resolution scanning and optical modeling of reflection and transmission spectra of coated glass. The thicknesses of the coatings were measured with an uncertainty of approximately 5%. The transmission and reflection properties of the coated glasses were determined using a Hitachi U-4000 spectrophotometer. Visible reflection and visible transmission of the coated glasses were determined using a D65 Illuminant and the second standard CIE observer, in accordance with ISO 9050 (Parry Moon air mass 2). the fogging of the coated glasses was measured using the WYK-Gardner Hasegurad device + fogging meter. Photocatalytic activity for the purposes of this specification is determined by measuring the percentage reduction of the integrated absorption peaks, which correspond to the CH expansions of a UVA lamp, which has an intensity of approximately 0.76 w / m<sup>2</sup>/ nm, on the surface of the substrate and a peak wavelength of 340 nm, for a period of 30 minutes. The stearic acid film can be formed by rotational molding of a solution of stearic acid and methanol on the surface of the substrate.
The stearic acid film was formed on samples of the glasses, of 7-8 square centimeters, by rotational molding of 20 μΐ of a solution of stearic acid in methanol (8.8 x 10<sup>-3</sup> mol.dm '<sup>3</sup>) on the glass coated surface, at 2000 rpm. Infrared spectra were measured in transmission. The coated side of the glass was illuminated with a UVA-351 lamp (obtained from Q20 Panel Co., Cleveland, Ohio, USA) that has a peak wavelength of 351 nm and a surface intensity of the coated glass of approximately 0.76 W / m<sup>2</sup>.
The static contact angle of the water in the coated glass was determined by measuring the diameter of a water droplet (volume in the range of 1 to 5 μΐ), placed on the surface of the coated glass, after irradiation of the coated glass, using a lamp
UV351 for about 2 hours (or as otherwise specified). In the preferred embodiments of the present invention, the contact angle is reduced to less than 10 ° and, in preferred embodiments, to less than 5 °.
The invention is illustrated by the following examples.
A series of deposit processes were carried out, using the equipment described in Figure 1.
Examples 1-6
Six deposition processes were carried out, the temperature of the glass at the point where the titanium precursor makes contact with it was 630 ° C. The line speed was 3 05 meters / hour. The process parameters are presented in Table 1.
TABLE ONE
<td>Example</td><td> 1</td><td> 2</td><td> 3</td><td> 4</td><td> 5</td><td> 6</td>
<td>Substrate</td><td>S / C</td><td>F / G</td><td>S / C</td><td>F / G</td><td>> S / C</td><td>S / C</td>
<td>Titanium precursor</td><td>KIND</td><td>KIND</td><td>KIND</td><td>TET</td><td>TET</td><td>TET</td>
<td>You Bubbler Temperature,! C</td><td> 160</td><td> 160</td><td> 160</td><td> 158</td><td> 174</td><td> 174</td>
<td>EtOAc bubbler Temperature, ° C</td><td> 60</td><td> 60</td><td> 60</td><td> 60</td><td> 60</td><td> 60</td>
<td>Flow regime of Bearer of You, Liters / minute</td><td> 0.8</td><td> 1.4</td><td> 1.4</td><td> 0.4</td><td> 0.8</td><td> 0.8</td>
<td>Flow regime of EtOAc carrier Liters / minute</td><td> 0.8</td><td> 0.</td><td> 0.75</td><td> 0.2</td><td> 0.2</td><td> 0.2</td>
<td>Flow rate of Balance Liters / minute</td><td> 25</td><td> 35</td><td> 35</td><td> 35</td><td> 35</td><td> 35</td>
S / C = Flow glass coated with silica TYPE = titanium tetraisopropoxide
F / G = uncoated soda-lime float glass
TET = titanium tetraethoxide.
Examples 7-12
A second series of six deposit processes was carried out. The temperature of the glass at the point where the titanium precursor contacted the glass was
625 ° C. The line speed was 550 meters / hour. In certain of these examples, a Oxygen gas stream was introduced and mixed with the precursor, immediately before deposition on the glass. The process parameters are presented in Table 2.
TABLE TWO
<td>Example</td><td> 7</td><td> 8</td><td> 9</td><td> 10</td><td> 115</td><td> 12</td>
<td>Substrate</td><td>F / G</td><td>F / G</td><td>F / G</td><td>F / G</td><td>S / C</td><td>S / C</td>
<td>Titanium precursor</td><td>KIND</td><td>KIND</td><td>KIND</td><td>TET</td><td>TET</td><td>TET</td>
<td>Ti delivered, cc / min.</td><td> 26</td><td> 26</td><td> 26</td><td> 11</td><td> 11</td><td> 11</td>
<td>touch delivered, cc / min.</td><td> 5</td><td> 3</td><td> 5</td><td> 5</td><td> 5</td><td> 5</td>
<td>Oxygen, liters / min.</td><td> 3</td><td> 3</td><td> 0</td><td> 06</td><td> 06</td><td> 06</td>
<td>Helium, liters / min.</td><td> 265</td><td> 265</td><td> 265</td><td> 265</td><td> 265</td><td> 265</td>
<td>Nitrogen, liters / min.</td><td> 290</td><td> 290</td><td> 290</td><td> 290</td><td> 290</td><td> 290</td>
The properties of the coated glasses produced in Examples 1 to 12 were measured. The results are presented in Table 3.
TABLE THREE
<td>Property</td><td>Thickness from uncle<sub>2</sub></td><td>Reflection %</td><td>Fog %</td><td>Angle or of Contact</td><td>Photoactivity % of removal after 30 minutes of exposition</td><td>Test of Humidity</td>
<td> 1</td><td> 120</td><td> 9.4</td><td> 0.18</td><td> 4.6</td><td> 95</td><td>Pass</td>
<td> 2</td><td> 360</td><td> 32.8</td><td> 0.35</td><td> 3.3</td><td> 95</td><td>Pass</td>
<td> 3</td><td> 184</td><td> 20.1</td><td> 0.24</td><td> 2.8</td><td> 95</td><td>Pass</td>
<td> 4</td><td> -</td><td> 21.2</td><td> 0.22</td><td> 4.4</td><td> 95</td><td>Pass</td>
<td> 5</td><td> 120</td><td> 15.8</td><td> 0.21</td><td> 5.6</td><td> 95</td><td>Pass</td>
<td> 6</td><td> 150</td><td> 22.1</td><td> 0.3</td><td> 3.5</td><td> 95</td><td>Pass</td>
<td> 7</td><td> 200</td><td> 20.5</td><td> 0.13</td><td> 6.0</td><td> 89</td><td>Pass</td>
<td> 8</td><td> 160</td><td> 11.9</td><td> 0.13</td><td> 4.7</td><td> 83</td><td>Pass</td>
<td> 9</td><td> 140</td><td> 10.4</td><td> 0.12</td><td> 5.6</td><td> 89</td><td>Pass</td>
<td> 10</td><td> 180</td><td> 19.2</td><td> 0.16</td><td> 5.6</td><td> 85</td><td>Pass</td>
<td> 11</td><td> 150</td><td> 10.9</td><td> 0.11</td><td> 5.0</td><td> 87</td><td>Pass</td>
<td> 12</td><td> 170</td><td> 13.5</td><td> 0.15</td><td> 5.3</td><td> 88</td><td>For</td>
Example 3
A third series of deposition processes was carried out using titanium tetraepoxide and ethyl acetate on a floating glass strip, having a thickness of 5.7 mm. The line speed was 351 meters 5 per hour. The deposition processes were carried out in one of two coating positions in the flotation bath. The glass temperature at these positions is shown in Table 4 below.
TABLE FOUR
<td>Temp .. of</td><td>Example</td><td>Flow</td><td>Delivery</td><td>Delivery</td><td>Rf%</td><td>NaOH 1</td>
<td>coater</td><td></td><td>principal</td><td>deTTTP</td><td>EtOAc</td><td></td><td>mol% @</td>
<td>From uncle<sub>2</sub></td><td></td><td>from He / N<sub>2</sub></td><td>cc / min.</td><td>cc / min</td><td></td><td>75! C</td>
<td> 700</td><td> 13</td><td> 600</td><td> 15</td><td> 0</td><td> 15.5</td><td>> 10 hrs</td>
<td> 700</td><td> 14</td><td> 600</td><td> 15</td><td> 4</td><td> 14.4</td><td>> 10 hrs</td>
<td> 700</td><td> 15</td><td> 600</td><td> 15</td><td> 8</td><td> 14.0</td><td>> 10 hrs</td>
<td> 700</td><td> 15</td><td> 600</td><td> 15</td><td> 12</td><td> 11.6</td><td>> 10 hr</td>
<td> 625</td><td> 17</td><td> 600</td><td> 11</td><td> 9</td><td> 15.8</td><td>> 10 hrs</td>
<td> 625</td><td> 18</td><td> 600</td><td> 11</td><td> 0</td><td> 21.2</td><td>> 10 hrs</td>
Certain properties of the coated glasses, produced in Examples 17 and 18, were measured and presented below in Table 6.
TABLE FIVE
<td>Example No.</td><td> 17</td><td> 18</td>
<td>T</td><td> 81.2</td><td> 76.2</td>
<td>a °</td><td> -2.2</td><td> -2.0</td>
<td>b *</td><td> 3.4</td><td> 5.4</td>
<td>R</td><td> 15.8</td><td> 21.2</td>
<td>to*</td><td> -0.1</td><td> -0.4</td>
<td>b *</td><td> -10.6</td><td> -12.3</td>
<td>r<sub>3</sub></td><td>0.59 nm</td><td>0.81 nm</td>
<td>Rms</td><td>0.77 nm</td><td>1.02 nm</td>
<td>Content of</td><td> 7%</td><td> 15%</td>
<td>Coal</td><td></td><td></td>
Example 18 is a comparative example of a deposition process carried out in the absence of ethyl acetate. AND Example 17 is an example of the invention, carried out using ethyl acetate. The product of
Example 17 can be seen is smoother and has a more neutral color.
Example 4
A fourth series of deposition processes was carried out using titanium tetraethoxide and ethyl acetate, on the glass float, having a thickness of 5.0 mm. The line speed was 434 meters per hour.
The deposition process was carried out in one of the coating arrangements, used in Example 3.
The process parameters are shown in Table 6.
TABLE SIX
<td>Temp .. of</td><td>Example</td><td>Flow</td><td>Delivery</td><td>Delivery</td><td>Rf%</td><td>NaOH 1</td>
<td>coater</td><td></td><td>principal</td><td>from TET</td><td>EtOAc</td><td></td><td>mol% @</td>
<td>From uncle<sub>2</sub></td><td></td><td>from He / N<sub>2</sub></td><td>cc / min.</td><td>cc / min</td><td></td><td>75! C</td>
<td> 700</td><td> 19</td><td> 600</td><td> 10.5</td><td> 0</td><td> 16.6</td><td>> 10hrs</td>
<td> 700</td><td> 20</td><td> 600</td><td> 10.5</td><td> 4.5</td><td> 16.1</td><td>> 10 hrs</td>
<td> 700</td><td> 21</td><td> 600</td><td> 10.5</td><td> 7.9</td><td> 16.0</td><td>> 10 hrs</td>
<td> 700</td><td> 22</td><td> 600</td><td> 10.5</td><td> 11.3</td><td> 16.0</td><td>> 10 hr</td>
<td> 625</td><td> 23</td><td> 600</td><td> 10.5</td><td> 0</td><td> 15.9</td><td>> 10 hrs</td>
<td> 625</td><td> 24</td><td> 600</td><td> 10.5</td><td> 4.5</td><td> 15.4.</td><td>> 10 hrs</td>
<td> 625</td><td> 25</td><td> 500</td><td> 10.5</td><td> 7.9</td><td> 15.6</td><td>> 10 hrs</td>
<td> 625</td><td> 26</td><td> 600</td><td> 10.5</td><td> 11.3</td><td> 15.6</td><td>> 10 hrs</td>
Example 5
A fifth series of deposition processes was carried out using titanium tetra-ethoxide and ethyl acetate on a floating glass strip, having a thickness of
3.2 mm. The line speed was 558 meters per hour. The processes were carried out where the glass temperature was 625 ° C. The process parameters are shown in the
Table 7.
TABLE SEVEN
<td>Temp .. of</td><td>Example</td><td>Flow</td><td>Delivery</td><td>Delivery</td><td>Rf%</td><td>NaOH 1</td>
<td>coater</td><td></td><td>principal</td><td>from TET</td><td>EtOAc</td><td></td><td>mol% @</td>
<td>From uncle<sub>2</sub></td><td></td><td>of He / N<sub>2</sub></td><td>cc / min.</td><td>cc / min</td><td></td><td>75! C</td>
<td> 625</td><td> 27</td><td> 600</td><td> 11.75</td><td> 5</td><td> 15.5</td><td>> 10 hrs</td>
<td> 625</td><td> 28</td><td> 600</td><td> 11.75</td><td> 6.6</td><td> 14.8</td><td>> 10hrs</td>
<td> 625</td><td> 29</td><td> 600</td><td> 11.75</td><td> 7.1</td><td> 14.3</td><td>> 10 hrs</td>
<td> 625</td><td> 30</td><td> 699</td><td> 11.75</td><td> 8.8</td><td> 14.2</td><td>> 10 hrs</td>
Example 6
In this series of examples, deposition was carried out using a laboratory directional coater. In this coater, a sheet of glass was heated over a conveyor oven, to simulate the conditions encountered in a floating glass production process. The glass was then passed to a reactor. A gaseous mixture, comprising helium, the precursor of titanium and ethyl acetate, was brought into contact with the upper surface of the glass. This gaseous mixture was formed by mixing the preheated gas streams, as noted in Table 7. The higher temperature of the glass initiated the deposition of the titanium oxide. The coated glass was removed and allowed to cool in air. The ·?
reflectivity and durability of coated glass was measured and recorded tro in Table 8.
TABLE EIGHT
<td>Key</td><td>Speed of</td><td>Flow</td><td>Flow</td><td>He / TTP</td><td>He / EtOAc</td><td>Rf%</td><td>NaOH1</td>
<td>Example</td><td>conveyor</td><td>principal</td><td>higher</td><td>Temp ..</td><td>Temp .. of</td><td></td><td>mol% @</td>
<td></td><td>inches / min</td><td>from he</td><td>from he</td><td>from 160 ° C</td><td>60 ° C</td><td></td><td>75 ° C</td>
<td> 31</td><td> 200</td><td> 18</td><td> 15</td><td> 0.2</td><td> 0.3</td><td> 14.42</td><td>> 10 hrs</td>
<td> 32</td><td> 200</td><td> 18</td><td> 15</td><td> 0.2</td><td> 0.6</td><td> 11.53</td><td>> 10 hrs</td>
<td colspan="8"></td>
<td> 33</td><td> 200</td><td> 18</td><td> 15</td><td> 0.2</td><td> 0</td><td> 13.91</td><td>> 10 hrs</td>
<td> 34</td><td> 200</td><td> 18</td><td> 15</td><td> 0.2</td><td> 0.3</td><td> 11.27</td><td>> 10 hrs</td>
<td colspan="8"></td>
<td> 35</td><td> 200</td><td> 18</td><td> 15</td><td> 0.3</td><td> 0</td><td> 17.60</td><td>> 10 hrs</td>
<td> 36</td><td> 200</td><td> 18</td><td> 15</td><td> 0.3</td><td> 0.3</td><td> 14.63</td><td>> 10 hrs</td>
<td colspan="8"></td>
<td> 37</td><td> 200</td><td> 18</td><td> 15</td><td> 0.24</td><td> 0.3</td><td> 15.22</td><td>> 10 hrs</td>
<td> 38</td><td> 200</td><td> 18</td><td> 15</td><td> 0.24</td><td> 0.13</td><td> 18.29</td><td>> 10 hrs</td>
The results are presented as pairs of experiments, which were carried out on the same date. The laboratory apparatus generates the gas streams from a heated bubbler, which contains the reagent, and the chemical delivery rate is sensitive to variations in temperature. mperature of bubbler. The setting of the bubbler temperature was not altered on any day and the delivery rates are thus comparable.
In each pair of experiments, it can be seen that the introduction of ethyl acetate produced a coating which has less reflection while the durability of the coating was not affected.
Example 7
A further series of deposition processes was carried out in the flotation bath, as described in the
Example 1 to 5 above. The results are presented in the
Table 9.
TABLE NINE
<td>Temp .. of coater from T1O2</td><td>Example</td><td>Flow principal from He / N<sub>2</sub></td><td>Delivery deTTTP cc / min.</td><td>Delivery from EtOAc cc / min</td><td>O2 liters / min</td><td>Rf%</td><td>NaOH1 mol% @ 75 ° C</td>
<td> 700</td><td> 39</td><td> 600</td><td> 15</td><td></td><td> 0</td><td> 14.4</td><td>very Good</td>
<td> 700</td><td> 40</td><td> 600</td><td> 15</td><td> 4</td><td> 0.5</td><td></td><td>failure</td>
<td> 700</td><td> 41</td><td> 600</td><td> 15</td><td> 4</td><td> 2.0</td><td> 14.1</td><td>failure</td>
<td> 700</td><td> 42</td><td> 600</td><td> 15</td><td> 12</td><td> 0</td><td> 11.9</td><td>very good</td>
Examples 40 and 41 introduce oxygen into the process of Example 13, which is represented here as the
Example 39. Illustrate them that the introduction of oxygen can have a detrimental effect on the coating. He
Example 42 is an example of a thin coating. This coating has a contact angle of 8.9 ° and was unaffected by 7 hours in the sodium hydroxide durability test and had a photoactivity of 90%.
Contents9
3 sheets
Sheet 1 Sheet 2 Sheet 3
16 members in 12 offices
Priority claims2
| Document | Office | Kind | Date |
|---|---|---|---|
| 0306797 | United Kingdom | A | |
| 2004001310 | United Kingdom | W |
Members16
| Document | Office | Kind | |
|---|---|---|---|
| GB0306797D0 | United Kingdom | D0 | |
| WO2004085701A1 | World Intellectual Property Organization (WIPO) | A1 | |
| MXPA05009815AThis record | Mexico | A | |
| EP1608793A1 | European Patent Office (EPO) | A1 | |
| BRPI0408115A | Brazil | A | |
| RU2005132838A | Russian Federation | A | |
| CN1764737A | China | A | |
| US2006194066A1 | United States of America | A1 | |
| JP2006521470A | Japan | A | |
| RU2351688C2 | Russian Federation | C2 | |
| EP1608793B1 | European Patent Office (EPO) | B1 | |
| AT467699T | Austria | T | |
| ATE467699T1 | Austria | T1 | |
| DE602004027124D1 | Germany | D1 | |
| ES2343630T3 | Spain | T3 | |
| BRPI0408115B1 | Brazil | B1 |
Numbers
- Application
- 5009815
Titles2
- English
- TITANIA COATINGS.
- Spanish
- RECUBRIMIENTOS DE TITANIA.
Classification
- CPC, 5
- C03C17/2456
- C03C2217/212
- C03C2217/71
- C03C2218/152
- C23C16/405
- IPC, 3
- B01J35 00
- C03C17 245
- C23C16 40