CA1117383A - Abrasion resistant coated window - Google Patents
Abrasion resistant coated windowInfo
- Publication number
- CA1117383A CA1117383A CA000309259A CA309259A CA1117383A CA 1117383 A CA1117383 A CA 1117383A CA 000309259 A CA000309259 A CA 000309259A CA 309259 A CA309259 A CA 309259A CA 1117383 A CA1117383 A CA 1117383A
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- Prior art keywords
- transparent
- film
- glass
- per cent
- colored
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Classifications
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- C—CHEMISTRY; METALLURGY
- C03—GLASS; MINERAL OR SLAG WOOL
- C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
- C03C17/00—Surface treatment of glass, not in the form of fibres or filaments, by coating
- C03C17/34—Surface treatment of glass, not in the form of fibres or filaments, by coating with at least two coatings having different compositions
- C03C17/3411—Surface treatment of glass, not in the form of fibres or filaments, by coating with at least two coatings having different compositions with at least two coatings of inorganic materials
- C03C17/3417—Surface treatment of glass, not in the form of fibres or filaments, by coating with at least two coatings having different compositions with at least two coatings of inorganic materials all coatings being oxide coatings
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- Chemical & Material Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Engineering & Computer Science (AREA)
- Chemical Kinetics & Catalysis (AREA)
- General Chemical & Material Sciences (AREA)
- Geochemistry & Mineralogy (AREA)
- Materials Engineering (AREA)
- Organic Chemistry (AREA)
- Surface Treatment Of Glass (AREA)
Abstract
ABRASION RESISTANT COATED WINDOW
Abstract of the Disclosure A window having a film of transparent, colored metal or metal oxide that acts to reflect heat and light is made abrasion resistant by overcoating its transparent, colored metal or metal oxide film with a clear, transparent film of tin oxide deposited at elevated temperatures to a thickness sufficient to provide abrasion resistance evidenced by less than two per cent haze following a standard Taber abrasion test for 1,000 revolutions.
Abstract of the Disclosure A window having a film of transparent, colored metal or metal oxide that acts to reflect heat and light is made abrasion resistant by overcoating its transparent, colored metal or metal oxide film with a clear, transparent film of tin oxide deposited at elevated temperatures to a thickness sufficient to provide abrasion resistance evidenced by less than two per cent haze following a standard Taber abrasion test for 1,000 revolutions.
Description
Background of the Invention This invention relates to the art of coating glass and particu- -larly relates to methods for preparing reflective, transparent films on glass by pyrolytic or other h~gh-temperature reaction deposition. The prior art to which this invention relates briefly includes the teachings of U.S. Patents No. 3,185,586 and No. 3,411,934 which concern .the depo-sition.of cobalt oxide onto glass, the second of which speciflcally teaches the deposition of cobalt oxide films over tin oxide primer fllms which are adhered directly to the glass. The prior art also includes teachings concerning the use of metal acetylacetonates as coating reactants ~o produce transparent, colored oxide films as evidenced by U.S~ Patents No. 3,081,200;
No. 3,410,710 and ~o. 3,660,061. Variou ~eth~ds for depositing tin oxide film on the glass are well known. ~ypical of the known methods for deposlting tin oxide is the method taught in U.S. Patent No. 3,107,177.
Over the years the various coating developments represented by the patents just mentioned has led to the commercial production of transparent, colored metal oxide fLlms which have substantial durability for use as films on glass used for external glazing of buildings. The films have sufficient chemical durability to withstand atmospheric attack by water, sulfur compounds, nitrogen compounds, salt dust and other corrosive and erosive materials normally found in the atmosphere.
The films commercially produced according to the teachings of these patents are observed to have decreased durability when the glass to which the films adhere is reheated for heat strengthening or tempering. There is a current need to consider heat strengthening or tempering glass which is used in glazing at ground level. ~here is also an emerging need to heat strengthen or to temper glass that is used in high-rise structures where the wind loading may be significant. It has also been found de-sirable to pro~ide heat-strengthened glass in structures where the thermal loading due to absorption of heat from the sun is sufficient to cause breakage of annealed glass. Ileat strengthening1 of course, permits the use of thinner glass than could ~e used when the glass is not strength-ened, and this permits a consequent reduction in weight which provides significant opportunities for improved structural design of buildings, particularly those employing glass curtain walls. Recently interest has developed in the use of heat and light-reflecting films on glass employed in motor homes, vans, and automobiles, particularly for use as sk~lights.
Glass employed for these purposes is preferably heat strengthened for reasons of safety and security. With the currently increasing incentive to employ heat-strengthened coated glass, attention has been directed to the problem of diminished abrasion resistance evidenced for metal oxide films which could otherwise be employed in the articles to be used for .
No. 3,410,710 and ~o. 3,660,061. Variou ~eth~ds for depositing tin oxide film on the glass are well known. ~ypical of the known methods for deposlting tin oxide is the method taught in U.S. Patent No. 3,107,177.
Over the years the various coating developments represented by the patents just mentioned has led to the commercial production of transparent, colored metal oxide fLlms which have substantial durability for use as films on glass used for external glazing of buildings. The films have sufficient chemical durability to withstand atmospheric attack by water, sulfur compounds, nitrogen compounds, salt dust and other corrosive and erosive materials normally found in the atmosphere.
The films commercially produced according to the teachings of these patents are observed to have decreased durability when the glass to which the films adhere is reheated for heat strengthening or tempering. There is a current need to consider heat strengthening or tempering glass which is used in glazing at ground level. ~here is also an emerging need to heat strengthen or to temper glass that is used in high-rise structures where the wind loading may be significant. It has also been found de-sirable to pro~ide heat-strengthened glass in structures where the thermal loading due to absorption of heat from the sun is sufficient to cause breakage of annealed glass. Ileat strengthening1 of course, permits the use of thinner glass than could ~e used when the glass is not strength-ened, and this permits a consequent reduction in weight which provides significant opportunities for improved structural design of buildings, particularly those employing glass curtain walls. Recently interest has developed in the use of heat and light-reflecting films on glass employed in motor homes, vans, and automobiles, particularly for use as sk~lights.
Glass employed for these purposes is preferably heat strengthened for reasons of safety and security. With the currently increasing incentive to employ heat-strengthened coated glass, attention has been directed to the problem of diminished abrasion resistance evidenced for metal oxide films which could otherwise be employed in the articles to be used for .
- 2 -~b~ ~ a 3~3~
the above-described purposes. This :invention is directed to a method for improving the abrasing resistance of tran~parent, colored metal and metal oxide films disposed on glass.
Sum~ary_of the Invention Thus, the invention in one aspect provides in a method of coating glass with a transparent, colored film containing at least one element selected from the group consisting of silicon, manganese, iron, cobalt, nickel, and copper wherein the film is deposited by reaction at a temperature of from 930F. (500C.) to 1300F. (710C.), the improvement which comprises depositing a clear, transparent film of tin oxide onto the transparent, colored film by contacting it, while ; it is at a temperature within the temperature range for depositing of the transparent, colored film, with a tin-containing compvsition until a tin oxide film thickness of from 300 ~ to 800 ~ is achieved whereby the film combination has an abrasion resistance sufficient to exhibit less than 2.0 per cent haze following standard Taber abrasion testing for 1,000 revolutions.
In more general terms a heat and light-reflecting, transparent, colored metal or metal oxide film is deposited on glass by reaction at a temperature within a range of from 930F. (500~C.) to 1300~F. (710C.). The film - may be a metal film, such as a silicon film that is deposited in a reducing environment. Alternatively, the film may be a metal oxide film ` deposited in an oxidizing environment. The metal oxide film is preferably one containing an oxide of at least one metal selected from manganese, iron, cobalt, nickel or copper. A preferred metal oxide film is one containing a mixture of metal oxides, such as a mixture of cobalt oxide9 chrome oxide and iron oxide. Particular metal oxides employed in the combination and amounts of each are selected to provide particularly desired heat and light-reflecting properties. The transparent, colored :
the above-described purposes. This :invention is directed to a method for improving the abrasing resistance of tran~parent, colored metal and metal oxide films disposed on glass.
Sum~ary_of the Invention Thus, the invention in one aspect provides in a method of coating glass with a transparent, colored film containing at least one element selected from the group consisting of silicon, manganese, iron, cobalt, nickel, and copper wherein the film is deposited by reaction at a temperature of from 930F. (500C.) to 1300F. (710C.), the improvement which comprises depositing a clear, transparent film of tin oxide onto the transparent, colored film by contacting it, while ; it is at a temperature within the temperature range for depositing of the transparent, colored film, with a tin-containing compvsition until a tin oxide film thickness of from 300 ~ to 800 ~ is achieved whereby the film combination has an abrasion resistance sufficient to exhibit less than 2.0 per cent haze following standard Taber abrasion testing for 1,000 revolutions.
In more general terms a heat and light-reflecting, transparent, colored metal or metal oxide film is deposited on glass by reaction at a temperature within a range of from 930F. (500~C.) to 1300~F. (710C.). The film - may be a metal film, such as a silicon film that is deposited in a reducing environment. Alternatively, the film may be a metal oxide film ` deposited in an oxidizing environment. The metal oxide film is preferably one containing an oxide of at least one metal selected from manganese, iron, cobalt, nickel or copper. A preferred metal oxide film is one containing a mixture of metal oxides, such as a mixture of cobalt oxide9 chrome oxide and iron oxide. Particular metal oxides employed in the combination and amounts of each are selected to provide particularly desired heat and light-reflecting properties. The transparent, colored :
- 3 -~ ;' ~:
metal oxide film is preferably deposited onto freshly-formed float glass which contains tin in its surface regions. The metal oxide film is deposited while the glass remains hot after forming and after it has been exposed briefly to an oxidizing environment. A preferred method for depositing the transparent, colored metal oxide film onto glass is the method described and claimed in U.S. patent No. 3,660,061 to Donley, Rieser and Wagner. The basic method of depositing a transparent, colored metal oxide onto glass is improved by depositing a clear, transparent film of tin oxide onto the transparent, colored metal oxide film.
This improvement is accomplished by contacting the transparent, colored metal or metal oxide film with a tin-containing composition comprising ,_ ~
~ - 3a -3~, an organo tin compound, such as dibutyl tin diacetate; a solvent 9 such as a lower aliphatic alcohol (for example, methanol); a fluorine compound, such as hydrofluoric acid (preferably as an alcohol solution); and a solvating agent, such as an alkyl amine (for example triethylamine).
The clear, transparent film of tin oxide is deposited onto the transparent, colored metal oxide film while it and the glass substrate to which it is affixed remain at a temperature within the same range of temperature as that for deposition of that transparent, colored metal oxide film. The clear, transparent film is deposited to a thickness of from about 300 A
O O
to 800 A. A thickness of at least about 500 A is preferred. The combin-ation of films which are produced provide the article with the color characteristlcs which are essentially unchanged from the color character-istics of the glass substrate with the transparent, colored metal oxide film alone. The abrasion resistance of the articles produced is signifi-cantly greater than the abrasion resistance of articles having the trans-parent, colored metal oxide film alone~ The abrasion resistance of the articles produced according to this invention is less than 2.0 and preferably less than 1.5 per cent haze following standard Taber abrasion testing for 1,000 revolutions as defined by ASA or ANSI standard Z26.1 Section 5.18 of the ASA or ANSI code as approved July 15, 1966 by the American Standards Association.
; In a preferred embodiment of this invention, the tin-containing composition contacts the transparent, colored metal oxide film substantially immediately following its deposition. Thus, in carrying out this embodi-ment of the invention, freshly-formed float glass is withdrawn from an enclosed float forming chamber having a reducing atmosphere within it and is immediately conveyed through a region exposed to air or an other-wise oxidizing atmosphere so that there is a brief superficial oxidization of tin surface of the glass. lhe glass is then coated with a trans-~ parent, colored metal oxide film in an oxidizing environment while its :;
temperature remains from about 1050F. (570C.) to 1200F. (650C.) and immediately thereafter the glass, which has a transparent, colored metal oxide film adhered to its surface, is contacted by a tin-containing composition such as described above while it is still at a temperature above 1050F. (570C.).
In a particularly preferred embodiment of this invention, the transparent, colored metal oxide film includes tin oxide in addition to the transparent, colored metal oxide which forms the basic portion of the film. Such a film provides a more acid-resistant article than other less preferred embodiments of the invention. Such a transparent, colored metal oxide film may be produced by employing a film-forming composition which contains a tin compound such as dibutyl tin oxide, dibutyl tin difluoride (the tin compound and fluorine compound may be one and the same) or any other convenient organo-tin compound including any alkyl or alkyl substituted tin compound. Following this, a tin oxide film is de-posited over the transparent, colored metal oxide film as described above.
In this particularly preferred embodiment oE this invention, after the glass has been coated with the clear, transparent tin oxide film, i~ is thermally tempered or heat-strengthened. Thermal tempering may be accomplished immediately by quenching the glass (which of course requires that the glass already be sized or cut prior to coating). In the event that the coating is accomplished on a continuous ribbon or sheet of glass coming from a continuous float forming chamber, the glass may be annealed and cut and then reheated and thermally tempered using a conventional thermal tempering cycle. A thermally tempered glass having the described combination of films is found to have an abrasion resistance of less than 2.0 per cent haze when subjected to standard Taber abrasion testing according to standard Z26.1, Section 5.18 of the ASA or ANSI code. In general, even after tempering, an abrasion resistance of less than about 1.7 per cent haze is achieved.
Brief Description of the Drawing_ This invention may be further understood with reference to the drawings:
FIG~ 1 is a sectional view of a portion of a gl2sS substrate having disposed on it the combination of metal oxide films which char- -acterize this invention; and FIG~ 2 is a partially cut-away perspective of a multiple glazed window employing as an outer pane of glass a coated glass plate or sheet such as that illustrated in FlGo 1~
Description of the Preferred Embodiments Referring now to the drawings, there are shown preferred embodiments of this invention. ~ glass substrate 1 has adhered to it a transparent, colored metal oxide fi.lm 5 which has adhered to it a clear, transparent tin oxide film 7. The glass is preferably a soda-lime-silica glass as typically employed for windows, mirrors and the like. It may, however, be a borosilicate glass or pure silica or any other glass composition which may be conveniently formed into plate or sheet form~ It may be flat or curved and it may be annealed, heat-strengthened or tempered. The glass 1 may be clear, transparent glass or a transparent, colored glass such as a bronze glass or a gray glass.
The transparent, colored metal oxide film 5 is a single metal oxide or a mixture of metal oxides.
In a preferred embodiment, a metal oxide film 5 is a mixture of chrome oxide, iron oxide and cobalt oxide, and a particular preferred embodiment contains these metal oxides in amounts of from 5 to 15 per cent chrome oxide; lO to 20 per cent iron oxide; 50 to 70 per cent cobalt oxide;
and 5 to 20 per cent tin oxide, with the amount of each constituent being present in an amount within its range to provide a sum of the constituents of 100 per cent. The clear, transparent tin oxide film 7 which is adhered to the metal oxide film 5 preferably has a thickness O c>
of from 500 A to 800 A. The thickness of the tin oxide film is such that, in the absence of a colored metal oxide film adjacent to it, it would appear to have a slight iridescent color; however, in the presence of the other film, it has no measurable coloration effect and is there-fore considered in this environment to be a clear film. The thickness of the tin oxide film may be appreciated from its surface resistance which is expressed conventionally as ohms per square. Since, the inherent bulk resistivity of a tin oxide film formed by chemical deposLtion at high temperature is stable, the surface resistance of such a tin oxide film is directly related to its thickness and may be used more conveniently to express the amount of film than the thickness itself which is somewhat difficult to measure directly. ~he thicklless of a tin oxide film which is effecti~ to provide abrasion resistallce is that which ~s ~epresented by a surface resistance of from 1,000 to 100,000 ohms per square. Films with surface resistances of from 10,000 to 30,000 ohms per square are believed to be of optimum thickness. Below about l,OOC ohms per square the films are so thick as to cause noticeable iridescence.
The article seen in FIG. 1 can be considered as a section of a window, such as a window that might be employed as a skylight in a van, camper or other recreational vehicles.
Referring specifically to FIG. 2, there is seen a multiple glazed window employing a combination like that shown in FIG. 1 as an exterior or outside sheet of glass. An interior sheet of glass 3 is disposed in spaced, parallel relation to glass sheet 1. A channel or frame 11 surrounds the marginal edges of the two sheets of glass 1 and 3 and serves to hold them together. A metal foil may be employed in place ?C3 ~ :~3 of the frame or channel 11 according to conventional practice. A mastic 13 adheres the sheets of glass to the frame 11 and provides an impervious seal or moisture barrier between the outside environment and the space between the two sheets of glass so that it may be hermetically sealed.
A spacer 15 is also adhered to the mastic between sheets of glass to maintain the space between them. The spacer may be a rubbery organic material which is flexible and elastic, as illustrated, and it may be a moisture, transmittable material containing a dispersed desiccant as illustrated; or, in the spacer 15 may be a conventional metal spacer which is hollow, contains a desiccant, and is provided with a series of openings to provide communication between the desiccant and the space between the two sheets of glass. The interior sheet of glass 3 may be a clear or colored, heat-absorbing glass and it may have a film disposed on one or both its surfaces, although it is illustrated in FIG. 2 as an uncoated sheet of glass. In a preferred embodiment of a multiple glazed unit empl~ying the multiple coated glass according to this invention as an e~terio~ sheet, the interior sheet of glass is simply an uncoated sheet of glass.
The signi~icance of the present invention may be further appreciated with reference to the following example in which the abrasion resistances of films on glass are compared:
; While it is recognized that a film on glass coated (in the manner of ~.S. Patent No. 3,660,061) immediat~ely after forming and following only a brief exposure to oxidizing conditions is more durable than a film produced on glass that has been annealed and then reheated to an appropriate temperature for coating, the following experimental comparison is based upon reheated coated glass that is annealed prior to coating. The comparative tests are considered equivalent in this regard and the durability'of films on glass made by either compared method ` -y~
but in the manner of U.S. Patent ~o. 3,660,061 would be expected to be proportionately more durable than those described. Thus, the comparison is believed to be a valid one.
A tin-containing concentrate composition is prepared by mi~ing together 18.925 liters of dibutyl tin diacetate (DBTA~, 15.847 liters of a hydrofluoric acid-methanol solution containing 30 per cent hydro-fluoric acid (HF) and 14.383 liters triethylamine (TEA). This concentrate solution is then diluted with methanol at a dilution ratio of three parts by volume methanol to one part by volume concentrate.
This diluted tin-containing solution may be used to overcoat a colored metal oxide film on glass such as the metal oxide film described aS formulation #8015 in U.S. Patent No. 3,660,061. Samples of glass repa~ed with this combînation of films have approximately the same o~tîcal and spectral properties as glass having the colored metal oxide film alone. The combination of films provides a product which, if annealed, has a haze of less than two per cent aEter standard Taber testing. A
Teledyne Taber abrasion testing device ~available from Teledyne-Tonawanda) i~ used to abrade samples and haze is deXermined using a Hunter Xazemeter, Model D 55 H with a 9.5 ~. Pump ~available from Hunter Labs.). Some samples which are reheated and tempered have haze readings slightly above two per cent.
In a preferred embodiment a formulation such as #8015 is modi~
fied by the addition of a tin compound to produce a colored metal oxide film containing tin oxide. For example, a modified #8015 formulation may be made by mixing seven parts by volume of the above-described concen-trate with 400 parts by volume #8015 solution wherein the #8015 solution comprises about two per cent by weight of solution metal and the remainder being organic material. The solvent system may be methylene chloride with `~'' _ g _ trichloroethylene and methanol and a phenolic compound or any solvent mixture as described in U.S. Patent No. 3,660,061. The final coating composition contains about two per cent metal and within its metal fraction alone there is the following approximate distribution of metals:
61.5 per cent cobalt; 15.4 per cent iron; 9.6 per cent chrornium; and 13.5 per cent tinO
Float glass samples (clear or colored may be used) are supported in a furnace and heated to a temperature within the range of from 1000 to 1250F. (535-930C.) and preferably to a temperature of from 1050 to 1100F.
(570-595C.). The surface of the glass which was its top surface during forming is sprayed with the mixed metal-containing solution and then immediately thereafter sprayed with the diluted tin-containing solution.
The coated glass is then annealed and coo:led or quenched to temper. Some annealed samplas are reheated and quenched to temper them. Reheating is to a temperature at or slightly above thal: for coating. Tempering is sufficient to provide for a modulus of rupture for 1/4 inch (7mm) thick glass of about ~0,000 pounds per square inch (1.38 x 10- pascal).
Both the annealed samples and the tempered samples have sufficient abrasion resistance to exhibit haze values of two per cent or less after standard Taber abrasion testing. An occasional tempered sample may have a higher haze value which is probably indicative of an insufficient tin oxide film thickness.
The spectral characteristics for multiple glazed units, such as shown in FIG. 2, indicate that the improvement provided by this invention allows the color and transmittance character of the films described in U.S. Patent No. 3,660,061 to be retained while achieving improved durability and abrasion resistance. For example, a gray glass substrate having a colored mixed metal oxide film on one surface has a visible light transmittance of ' 3~33 about 19 to 20 per cent alone or in a multiple glazed window with a second pane of clear glass. Modified and with a tin oxide overcoat the visible light transmittance is in the same range. Likewise, for a bronze glass substrate, which alone has a visible light transmittance of about 21 to 22 per cent and in a multiple glazed unit has a visible light transmittance of about 19 to 21 per cent, the modified film with a tin oxide film provides products with transmittance properties in the same ranges.
The observations with respect to use of a tin oxide film to protect a silicon film on glass are limited, but it appears that a gray colored silicon film on glass which is subject to ready abrasion is protected by an overcoat of tin oxide. A sample of glass having a clear-to-gray silicon film was masked and half of the silicon film was overcoated with tin oxide in the manner previously described for applying a tin oxide film. The silicon film-glass combination alone had a visible light transmittance of 6~ per cent. After coating the tin oxide-silicon-glass combination had a visible light transmittance oE 67 per cent.
Since the sample was not sized for standard abrasion testing, its abrasion resistance was qualitatively evaluated. Both the previously masked area of the sample having the silicon film exposed and the tin oxide overcoated area were subjected together to twenty rubs with wet cerium oxide. The silicon film was removed from the glass; the tin oxide overcoated film was not scratched as visually observed. From this, it is believed that a sufficiently thick film of tin oxide may be provided to yield a product having the quantative resistance to abrasion described above.
While this invention has been described with reference to its particularly preferred embodiments, those skilled in the art will appreciate that equivalent variations may be made within the scope of the invention which, though differing rom these described embodiments, are contemplated by the claims which follow.
metal oxide film is preferably deposited onto freshly-formed float glass which contains tin in its surface regions. The metal oxide film is deposited while the glass remains hot after forming and after it has been exposed briefly to an oxidizing environment. A preferred method for depositing the transparent, colored metal oxide film onto glass is the method described and claimed in U.S. patent No. 3,660,061 to Donley, Rieser and Wagner. The basic method of depositing a transparent, colored metal oxide onto glass is improved by depositing a clear, transparent film of tin oxide onto the transparent, colored metal oxide film.
This improvement is accomplished by contacting the transparent, colored metal or metal oxide film with a tin-containing composition comprising ,_ ~
~ - 3a -3~, an organo tin compound, such as dibutyl tin diacetate; a solvent 9 such as a lower aliphatic alcohol (for example, methanol); a fluorine compound, such as hydrofluoric acid (preferably as an alcohol solution); and a solvating agent, such as an alkyl amine (for example triethylamine).
The clear, transparent film of tin oxide is deposited onto the transparent, colored metal oxide film while it and the glass substrate to which it is affixed remain at a temperature within the same range of temperature as that for deposition of that transparent, colored metal oxide film. The clear, transparent film is deposited to a thickness of from about 300 A
O O
to 800 A. A thickness of at least about 500 A is preferred. The combin-ation of films which are produced provide the article with the color characteristlcs which are essentially unchanged from the color character-istics of the glass substrate with the transparent, colored metal oxide film alone. The abrasion resistance of the articles produced is signifi-cantly greater than the abrasion resistance of articles having the trans-parent, colored metal oxide film alone~ The abrasion resistance of the articles produced according to this invention is less than 2.0 and preferably less than 1.5 per cent haze following standard Taber abrasion testing for 1,000 revolutions as defined by ASA or ANSI standard Z26.1 Section 5.18 of the ASA or ANSI code as approved July 15, 1966 by the American Standards Association.
; In a preferred embodiment of this invention, the tin-containing composition contacts the transparent, colored metal oxide film substantially immediately following its deposition. Thus, in carrying out this embodi-ment of the invention, freshly-formed float glass is withdrawn from an enclosed float forming chamber having a reducing atmosphere within it and is immediately conveyed through a region exposed to air or an other-wise oxidizing atmosphere so that there is a brief superficial oxidization of tin surface of the glass. lhe glass is then coated with a trans-~ parent, colored metal oxide film in an oxidizing environment while its :;
temperature remains from about 1050F. (570C.) to 1200F. (650C.) and immediately thereafter the glass, which has a transparent, colored metal oxide film adhered to its surface, is contacted by a tin-containing composition such as described above while it is still at a temperature above 1050F. (570C.).
In a particularly preferred embodiment of this invention, the transparent, colored metal oxide film includes tin oxide in addition to the transparent, colored metal oxide which forms the basic portion of the film. Such a film provides a more acid-resistant article than other less preferred embodiments of the invention. Such a transparent, colored metal oxide film may be produced by employing a film-forming composition which contains a tin compound such as dibutyl tin oxide, dibutyl tin difluoride (the tin compound and fluorine compound may be one and the same) or any other convenient organo-tin compound including any alkyl or alkyl substituted tin compound. Following this, a tin oxide film is de-posited over the transparent, colored metal oxide film as described above.
In this particularly preferred embodiment oE this invention, after the glass has been coated with the clear, transparent tin oxide film, i~ is thermally tempered or heat-strengthened. Thermal tempering may be accomplished immediately by quenching the glass (which of course requires that the glass already be sized or cut prior to coating). In the event that the coating is accomplished on a continuous ribbon or sheet of glass coming from a continuous float forming chamber, the glass may be annealed and cut and then reheated and thermally tempered using a conventional thermal tempering cycle. A thermally tempered glass having the described combination of films is found to have an abrasion resistance of less than 2.0 per cent haze when subjected to standard Taber abrasion testing according to standard Z26.1, Section 5.18 of the ASA or ANSI code. In general, even after tempering, an abrasion resistance of less than about 1.7 per cent haze is achieved.
Brief Description of the Drawing_ This invention may be further understood with reference to the drawings:
FIG~ 1 is a sectional view of a portion of a gl2sS substrate having disposed on it the combination of metal oxide films which char- -acterize this invention; and FIG~ 2 is a partially cut-away perspective of a multiple glazed window employing as an outer pane of glass a coated glass plate or sheet such as that illustrated in FlGo 1~
Description of the Preferred Embodiments Referring now to the drawings, there are shown preferred embodiments of this invention. ~ glass substrate 1 has adhered to it a transparent, colored metal oxide fi.lm 5 which has adhered to it a clear, transparent tin oxide film 7. The glass is preferably a soda-lime-silica glass as typically employed for windows, mirrors and the like. It may, however, be a borosilicate glass or pure silica or any other glass composition which may be conveniently formed into plate or sheet form~ It may be flat or curved and it may be annealed, heat-strengthened or tempered. The glass 1 may be clear, transparent glass or a transparent, colored glass such as a bronze glass or a gray glass.
The transparent, colored metal oxide film 5 is a single metal oxide or a mixture of metal oxides.
In a preferred embodiment, a metal oxide film 5 is a mixture of chrome oxide, iron oxide and cobalt oxide, and a particular preferred embodiment contains these metal oxides in amounts of from 5 to 15 per cent chrome oxide; lO to 20 per cent iron oxide; 50 to 70 per cent cobalt oxide;
and 5 to 20 per cent tin oxide, with the amount of each constituent being present in an amount within its range to provide a sum of the constituents of 100 per cent. The clear, transparent tin oxide film 7 which is adhered to the metal oxide film 5 preferably has a thickness O c>
of from 500 A to 800 A. The thickness of the tin oxide film is such that, in the absence of a colored metal oxide film adjacent to it, it would appear to have a slight iridescent color; however, in the presence of the other film, it has no measurable coloration effect and is there-fore considered in this environment to be a clear film. The thickness of the tin oxide film may be appreciated from its surface resistance which is expressed conventionally as ohms per square. Since, the inherent bulk resistivity of a tin oxide film formed by chemical deposLtion at high temperature is stable, the surface resistance of such a tin oxide film is directly related to its thickness and may be used more conveniently to express the amount of film than the thickness itself which is somewhat difficult to measure directly. ~he thicklless of a tin oxide film which is effecti~ to provide abrasion resistallce is that which ~s ~epresented by a surface resistance of from 1,000 to 100,000 ohms per square. Films with surface resistances of from 10,000 to 30,000 ohms per square are believed to be of optimum thickness. Below about l,OOC ohms per square the films are so thick as to cause noticeable iridescence.
The article seen in FIG. 1 can be considered as a section of a window, such as a window that might be employed as a skylight in a van, camper or other recreational vehicles.
Referring specifically to FIG. 2, there is seen a multiple glazed window employing a combination like that shown in FIG. 1 as an exterior or outside sheet of glass. An interior sheet of glass 3 is disposed in spaced, parallel relation to glass sheet 1. A channel or frame 11 surrounds the marginal edges of the two sheets of glass 1 and 3 and serves to hold them together. A metal foil may be employed in place ?C3 ~ :~3 of the frame or channel 11 according to conventional practice. A mastic 13 adheres the sheets of glass to the frame 11 and provides an impervious seal or moisture barrier between the outside environment and the space between the two sheets of glass so that it may be hermetically sealed.
A spacer 15 is also adhered to the mastic between sheets of glass to maintain the space between them. The spacer may be a rubbery organic material which is flexible and elastic, as illustrated, and it may be a moisture, transmittable material containing a dispersed desiccant as illustrated; or, in the spacer 15 may be a conventional metal spacer which is hollow, contains a desiccant, and is provided with a series of openings to provide communication between the desiccant and the space between the two sheets of glass. The interior sheet of glass 3 may be a clear or colored, heat-absorbing glass and it may have a film disposed on one or both its surfaces, although it is illustrated in FIG. 2 as an uncoated sheet of glass. In a preferred embodiment of a multiple glazed unit empl~ying the multiple coated glass according to this invention as an e~terio~ sheet, the interior sheet of glass is simply an uncoated sheet of glass.
The signi~icance of the present invention may be further appreciated with reference to the following example in which the abrasion resistances of films on glass are compared:
; While it is recognized that a film on glass coated (in the manner of ~.S. Patent No. 3,660,061) immediat~ely after forming and following only a brief exposure to oxidizing conditions is more durable than a film produced on glass that has been annealed and then reheated to an appropriate temperature for coating, the following experimental comparison is based upon reheated coated glass that is annealed prior to coating. The comparative tests are considered equivalent in this regard and the durability'of films on glass made by either compared method ` -y~
but in the manner of U.S. Patent ~o. 3,660,061 would be expected to be proportionately more durable than those described. Thus, the comparison is believed to be a valid one.
A tin-containing concentrate composition is prepared by mi~ing together 18.925 liters of dibutyl tin diacetate (DBTA~, 15.847 liters of a hydrofluoric acid-methanol solution containing 30 per cent hydro-fluoric acid (HF) and 14.383 liters triethylamine (TEA). This concentrate solution is then diluted with methanol at a dilution ratio of three parts by volume methanol to one part by volume concentrate.
This diluted tin-containing solution may be used to overcoat a colored metal oxide film on glass such as the metal oxide film described aS formulation #8015 in U.S. Patent No. 3,660,061. Samples of glass repa~ed with this combînation of films have approximately the same o~tîcal and spectral properties as glass having the colored metal oxide film alone. The combination of films provides a product which, if annealed, has a haze of less than two per cent aEter standard Taber testing. A
Teledyne Taber abrasion testing device ~available from Teledyne-Tonawanda) i~ used to abrade samples and haze is deXermined using a Hunter Xazemeter, Model D 55 H with a 9.5 ~. Pump ~available from Hunter Labs.). Some samples which are reheated and tempered have haze readings slightly above two per cent.
In a preferred embodiment a formulation such as #8015 is modi~
fied by the addition of a tin compound to produce a colored metal oxide film containing tin oxide. For example, a modified #8015 formulation may be made by mixing seven parts by volume of the above-described concen-trate with 400 parts by volume #8015 solution wherein the #8015 solution comprises about two per cent by weight of solution metal and the remainder being organic material. The solvent system may be methylene chloride with `~'' _ g _ trichloroethylene and methanol and a phenolic compound or any solvent mixture as described in U.S. Patent No. 3,660,061. The final coating composition contains about two per cent metal and within its metal fraction alone there is the following approximate distribution of metals:
61.5 per cent cobalt; 15.4 per cent iron; 9.6 per cent chrornium; and 13.5 per cent tinO
Float glass samples (clear or colored may be used) are supported in a furnace and heated to a temperature within the range of from 1000 to 1250F. (535-930C.) and preferably to a temperature of from 1050 to 1100F.
(570-595C.). The surface of the glass which was its top surface during forming is sprayed with the mixed metal-containing solution and then immediately thereafter sprayed with the diluted tin-containing solution.
The coated glass is then annealed and coo:led or quenched to temper. Some annealed samplas are reheated and quenched to temper them. Reheating is to a temperature at or slightly above thal: for coating. Tempering is sufficient to provide for a modulus of rupture for 1/4 inch (7mm) thick glass of about ~0,000 pounds per square inch (1.38 x 10- pascal).
Both the annealed samples and the tempered samples have sufficient abrasion resistance to exhibit haze values of two per cent or less after standard Taber abrasion testing. An occasional tempered sample may have a higher haze value which is probably indicative of an insufficient tin oxide film thickness.
The spectral characteristics for multiple glazed units, such as shown in FIG. 2, indicate that the improvement provided by this invention allows the color and transmittance character of the films described in U.S. Patent No. 3,660,061 to be retained while achieving improved durability and abrasion resistance. For example, a gray glass substrate having a colored mixed metal oxide film on one surface has a visible light transmittance of ' 3~33 about 19 to 20 per cent alone or in a multiple glazed window with a second pane of clear glass. Modified and with a tin oxide overcoat the visible light transmittance is in the same range. Likewise, for a bronze glass substrate, which alone has a visible light transmittance of about 21 to 22 per cent and in a multiple glazed unit has a visible light transmittance of about 19 to 21 per cent, the modified film with a tin oxide film provides products with transmittance properties in the same ranges.
The observations with respect to use of a tin oxide film to protect a silicon film on glass are limited, but it appears that a gray colored silicon film on glass which is subject to ready abrasion is protected by an overcoat of tin oxide. A sample of glass having a clear-to-gray silicon film was masked and half of the silicon film was overcoated with tin oxide in the manner previously described for applying a tin oxide film. The silicon film-glass combination alone had a visible light transmittance of 6~ per cent. After coating the tin oxide-silicon-glass combination had a visible light transmittance oE 67 per cent.
Since the sample was not sized for standard abrasion testing, its abrasion resistance was qualitatively evaluated. Both the previously masked area of the sample having the silicon film exposed and the tin oxide overcoated area were subjected together to twenty rubs with wet cerium oxide. The silicon film was removed from the glass; the tin oxide overcoated film was not scratched as visually observed. From this, it is believed that a sufficiently thick film of tin oxide may be provided to yield a product having the quantative resistance to abrasion described above.
While this invention has been described with reference to its particularly preferred embodiments, those skilled in the art will appreciate that equivalent variations may be made within the scope of the invention which, though differing rom these described embodiments, are contemplated by the claims which follow.
Claims (8)
1. In a method of coating glass with a transparent, colored film containing at least one element selected from the group consisting of silicon, manganese, iron, cobalt, nickel, and copper wherein the film is deposited by reaction at a temperature of from 930°F. (500°C.) to 1300°F. (710°C.), the improvement which comprises depositing a clear, transparent film of tin oxide onto the transparent, colored film by contacting it, while it is at a temperature within the temperature range for depositing of the transparent, colored film, with a tin-containing composition until a tin oxide film thickness of from 300 .ANG. to 800 .ANG. is achieved whereby the film combination has an abrasion resistance sufficient to exhibit less than 2.0 per cent haze following standard Taber abrasion testing for 1,000 revolutions.
2. The method according to Claim 1 wherein the transparent, colored film is contacted by the tin-containing composition substantially immediately following its deposition.
3. The method according to Claim 1 wherein the transparent, colored film is deposited on the glass while it remains hot from forming and the tin-containing composition contacts it while its temperature is maintained within the temperature range for said deposition.
4. The method according to Claim 1 wherein the transparent, colored film includes tin oxide.
5. The method according to Claim 4 wherein the method further comprises thermally tempering the glass and its two-film combination.
6. An article of manufacture produced by the method of Claim l comprising a transparent glass substrate, a transparent, colored film affixed to a surface of the glass substrate and a clear, transparent tin oxide film having a thickness of from 300 .ANG. to 800 .ANG. affixed to the transparent, colored metal oxide film, which film combination has an abrasion resistance susceptible of less than 2.0 per cent haze following standard Taber abrasion testing for 1,000 revolutions.
7. The article of manufacture according to Claim 6 wherein the transparent, colored film is a metal oxide film containing 5-15 per cent chrome oxide; 10-20 per cent iron oxide; 50-70 per cent cobalt oxide; and 5-20 per cent tin oxide.
8. The article of manufacture according to Claim 7 wherein the article is thermally tempered.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000309259A CA1117383A (en) | 1978-08-14 | 1978-08-14 | Abrasion resistant coated window |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000309259A CA1117383A (en) | 1978-08-14 | 1978-08-14 | Abrasion resistant coated window |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1117383A true CA1117383A (en) | 1982-02-02 |
Family
ID=4112120
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000309259A Expired CA1117383A (en) | 1978-08-14 | 1978-08-14 | Abrasion resistant coated window |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1117383A (en) |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2288818A (en) * | 1994-04-27 | 1995-11-01 | Glaverbel | Glazing panel |
| EP0735009A1 (en) * | 1995-03-30 | 1996-10-02 | Central Glass Company, Limited | Heat reflecting glass |
| US5721054A (en) * | 1994-04-27 | 1998-02-24 | Glaverbel | Glazing panel and process for forming the same |
| WO1998011031A1 (en) * | 1996-09-13 | 1998-03-19 | Pilkington Plc | Coated glass |
| JP2002012451A (en) * | 2000-04-28 | 2002-01-15 | Asahi Glass Co Ltd | Glass coated with coloring film reflecting heat ray and its manufacturing method |
| EP1288174A1 (en) * | 2000-04-28 | 2003-03-05 | Asahi Glass Company Ltd. | Glass coated with heat reflecting colored film and method for manufacturing the same |
-
1978
- 1978-08-14 CA CA000309259A patent/CA1117383A/en not_active Expired
Cited By (20)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2288818A (en) * | 1994-04-27 | 1995-11-01 | Glaverbel | Glazing panel |
| DE19515015A1 (en) * | 1994-04-27 | 1995-11-02 | Glaverbel | Glazing pane and method for its production |
| FR2719305A1 (en) * | 1994-04-27 | 1995-11-03 | Glaverbel | Glazing and method of manufacturing such a glazing. |
| DE19515015B4 (en) * | 1994-04-27 | 2010-05-12 | Agc Flat Glass Europe S.A. | Glazing pane and method for its production |
| NL1000237C2 (en) * | 1994-04-27 | 1996-12-17 | Glaverbel | Glass panel and method of forming it. |
| BE1009514A3 (en) * | 1994-04-27 | 1997-04-01 | Glaverbel | Glass and method for manufacturing a glass tel. |
| GB2288818B (en) * | 1994-04-27 | 1997-12-24 | Glaverbel | Glazing panel and process for forming the same |
| US5721054A (en) * | 1994-04-27 | 1998-02-24 | Glaverbel | Glazing panel and process for forming the same |
| AT408979B (en) * | 1994-04-27 | 2002-04-25 | Glaverbel | GLAZING WINDOW AND METHOD FOR THEIR PRODUCTION |
| ES2115496A1 (en) * | 1994-04-27 | 1998-06-16 | Glaverbel | Glazing panel |
| US5894047A (en) * | 1995-03-30 | 1999-04-13 | Central Glass Company, Limited | Heat reflecting glass |
| EP0735009A1 (en) * | 1995-03-30 | 1996-10-02 | Central Glass Company, Limited | Heat reflecting glass |
| US6048621A (en) * | 1996-09-13 | 2000-04-11 | Pilkington Plc | Coated glass |
| AU718586B2 (en) * | 1996-09-13 | 2000-04-13 | Pilkington Plc | Improvements in or related to coated glass |
| WO1998011031A1 (en) * | 1996-09-13 | 1998-03-19 | Pilkington Plc | Coated glass |
| CN1108997C (en) * | 1996-09-13 | 2003-05-21 | 皮尔金顿公共有限公司 | Coated glass |
| JP2002012451A (en) * | 2000-04-28 | 2002-01-15 | Asahi Glass Co Ltd | Glass coated with coloring film reflecting heat ray and its manufacturing method |
| EP1288174A1 (en) * | 2000-04-28 | 2003-03-05 | Asahi Glass Company Ltd. | Glass coated with heat reflecting colored film and method for manufacturing the same |
| EP1288174A4 (en) * | 2000-04-28 | 2005-06-08 | Asahi Glass Co Ltd | Glass coated with heat reflecting colored film and method for manufacturing the same |
| US7303658B2 (en) | 2000-04-28 | 2007-12-04 | Asahi Glass Company, Limited | Glass coated with heat reflecting colored film and process for its production |
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| Date | Code | Title | Description |
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| MKEX | Expiry |