Compounds and compositions for coating glass and coated glass substrates

Summary (continued) (57)

DO NOT FILL SHADOW ZONES where R_x is a group that must not have oxygen available to form a peroxide, R₂ is a functional group that gives the silicon-containing precursor the ability to easily convert to silicon oxide coating, R₃ is a bridging group to provide multiple silicon atoms and R₄ completes the bond at the central silicon atom. An accelerator may be used, e.g. ex. , a phosphorus-containing precursor with metal-containing precursors to increase the deposition rate of the coating. 0 Coating deposited on the glass has silicon oxide and tin oxide weight percent regions continuously varying as the distance to the glass-coating interface increases, with the surface of the coating further away from the glass-coating interface being predominantly tin oxide. . The regions within the coating provide different refractive indices to eliminate the iridescence resulting from the increased thickness of the tin oxide on the exterior coating surface and to give the glass article a neutral color. When phosphorus is used as the accelerator, the crystallinity percentage is reduced and approaches zero, thereby reducing or eliminating the coating mist.

.UES.GRIÇAQ

GLASS COATING APPARATUS, GLASS COATING METHOD, GLASS COATING COMPOUNDS AND COMPOSITIONS AND COATED GLASS SUBSTRATES

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AMLECEDEtITES ^ O „INVENTQ

1. Field of the Invention

Mod. 71 - 20,000 ex. · 92/12

This invention relates to a method of and apparatus for the chemical vapor deposition of one or more metal oxides on a substrate, e.g. ex. silicon-containing precursors used in the preparation of silicon oxide-containing coating compositions and the product (s), e.g. ex. coated glass made in this way.

2. Description of Related Art

It is known in the art that when a film of a transparent metal oxide, such as tin oxide, is deposited on a glass substrate, the coated glass substrate exhibits a non-uniform light reflection across the visible spectrum due to the difference in index. refraction between metal oxide and glass substrate. Additionally, when the thickness of the metal oxide is not uniform, the. Coating tends to exhibit a multitude of commonly referred to as iridescent color interference effects. These iridescent effects make coated glass aesthetically unacceptable for most architectural applications. Thus, various methods have been proposed to mask such iridiscence effects and / or reduce reflectance.

A technique for minimizing or eliminating the refractive index difference between the metal oxide and the glass substrate is disclosed in US Pat. No. 3,378,396 to Zaromb, in which a glass substrate is coated simultaneously by directing individual sprayers of a tin solution and a silicon chloride solution onto an immovable piece of glass heated in an oxidizing atmosphere, e.g. ex. air. 0 Heat from the glass piece thermally converts the metal chlorides into their oxides. The ratio of the nozzles to each other is gradually varied to vary the ratio of the weight percent of metal oxides in the coating. The resulting coating has a continuously changing composition throughout its thickness, e.g. ex. near the glass-coating interface the coating is predominantly silicon oxide, the surface of the coating furthest from the glass-coating interface is predominantly tin oxide and between them the coating is made up of varying amounts of weight percent silicon oxide and oxide Tin Strong, in his titled publication Practical Applications of High and Low-Reflecting Films on Glass, ”pages 441-443 of Le. Jpurnal_de_Ehlslgue et Le Radium. vol. 11, July 1950, teaches that a coating technique similar to that taught by Zarombe reduces the iridescence of the coated article.

In addition, techniques that use Zaromb's teachings to coat a moving substrate are disclosed in US Pat. No. 4,206,252 and 4,440,882. These patents further teach the deposition of a second coating composed of fluoride-doped tin oxide on the first coating of the type taught by Zaromb.

Mod. 71 · 20,000 and '. 92/12

Gordon, in US Pat. 4 187 336 and 4,303,316, discloses the reduction of iridescence of a tin oxide coating on a glass substrate by the use of an intermediate coating between the tin oxide coating and the glass substrate having a thickness and an index of refraction satisfying the optical equation: the refractive index of the intermediate coating is equal to the square root of the refractive index of the glass substrate multiplied by the refractive index of the tin oxide coating.

U.S. Pat. No. 4,377,613 and 4,419,386 to Gordon disclose a reduction in iridescence from a tin oxide film on a glass substrate by providing two intermediate coating layers between the glass substrate and the tin oxide. The intermediate layer near the surface of the glass substrate has a high refractive index, while the intermediate layer near the surface of the tin oxide film has a low refractive index.

In general, the patents discussed above except U.S. Pat. No. 4,206,252 and 4,440,882 teach how to coat a motionless substrate. Apparatus for coating a moving substrate with metal oxides is disclosed in US Pat. 4,206,252 and 4,440,882 issued to Gordon, discussed above, and in US Patent θ. No. 4,853,257, issued to Henery, and in US Patent No. 2. 4,386,117 issued to Gordon. ....................

In US Pat. No. 4,206,252 and 4,440,882, the underside of a moving hot glass strip is coated by orienting coating compositions containing metal compounds toward the surface of the strip.

Mod. 71 20,000 ex. 92/12 and these compounds are converted to their corresponding metal oxides.

U.S. Patent No. No. 4,853,257 discloses an apparatus for depositing a low emissivity film onto a glass strip by orienting vapor-containing metal-containing coating reagents on the upper surface of a glass strip while the glass strip is supported over a bath. of molten metal contained in a non-oxidizing atmosphere. 0 carrier gas, unreacted coating composition and any decomposition by-products are removed from the coating zone by an exhaust port on each side of and equidistant from the position where the vapor-shaped coating reagents are oriented to the strip. of glass.

U.S. Patent No. 2. No. 4,386,117 discloses a process for depositing a mixed metal oxide coating onto a glass substrate by orienting a gaseous mixture over a moving glass strip and then escaping the coating zone gases at two locations equidistant from the inlet. gas mixture to the coating zone.

While each of the apparatus and processes taught in the patents discussed above are acceptable for their intended purpose, there are limitations when apparatus and methods are used to apply Zaromb's coating to a moving heated substrate, e.g. ex. a range of ........... glass supported in a molten metal bath contained in a non-oxidizing atmosphere. Accordingly, it will be advantageous to provide apparatus and methods for depositing the Zaromb coating on a moving heated surface as well as the metal containing precursors used in the preparation of the coating.

Mod. 71 - 20,000 ex. - 92/12

One of the limitations of the steam coating system currently available for coating a glass band moving at high speeds, e.g. ex. about 0.254 meters / s (600 in./min) is that the vapor coating mixture does not have enough time to deposit an acceptable coating thickness over the glass strip. The article titled The LPCVD of Silicon Oxide Films Below 400 ° C (700 ° F) From Liquid Sources by AK Hochberg and DL O'Meara published in J.Electrochem. Soc. Vol. 136, N2. 6, June 1989, protected by The Electrochemical Society, Inc., pages 1843 and 1844, teaches the use of trimethylphosphite to accelerate coating deposition below 400 ° C (700 ° F). User'8 Guide For: Glass Deposition with LT0-410 ™ Source Material by Dr. A. Hochberg and Dr. B. Gelernt, protected in 1990 by Schumacher of Carisbad, California, 92009, teaches that LT0-410 not significantly altered by the addition of trimethylphosphite.

Although the use of accelerators is taught, there are no teachings that accelerators are beneficial at elevated temperatures, e.g. ex. above 400 ° C (700 ° F). Accordingly, it would be advantageous to provide accelerators for coating systems operating at temperatures above about 536 ° C (1000 ° F).

²⁵ SUMMARY OF THE INVENTION The invention relates to a method for coating a moving substrate, e.g. ex. a strip of glass, supported and ...... in progression over a pool of molten metal, p. ex. tin, by a film or coating that has a continuously changing chemical composition as the distance to the glass-coating interface increases. The method includes the steps of orienting a metal-containing precursor vapor coating composition, e.g. ex. a precursor

Mod. 71 · 20,000 and '. 92/12 containing silicon and a tin-containing precursor on the glass strip surface of moving a first portion of the vapor through a first strip surface region in a first direction and a second steam portion through a second region in the second opposite direction, and maintaining the first portion of the coating composition over the first region for a longer period of time than the second portion of the coating composition over the second region, to provide a coating on the glass strip having a varying metal oxide composition as the distance to the glass coating interface increases.

Furthermore, the invention relates to an apparatus for carrying out the method. One embodiment of the inventive apparatus includes means for orienting a mixed metal-containing precursor vapor onto a substrate, e.g. ex. the glass strip supported on a molten tin bath. A first exhaust is spaced from the steam orientating means on one side thereof, a second exhaust is spaced from the steam orientating means on its other side and aligned with the steam orienting means. 0 The first exhaust is spaced from the steam orifice a different distance than the second exhaust is spaced from the steam orienting means.

The invention further relates to a transparent substrate, e.g. ex. a glass substrate having a coating of mixed metal oxides thereon, e.g. ex. silic oxide and tin oxide The coating composition has a ratio of silic oxide to tin oxide that changes continuously as the distance to the glass coating interface increases, e.g. ex. substantially all silicon oxide at the glass-coating interface and substantially all tin oxide at the opposite coating surface. Between the glass-coating interface and the opposite coating surface if there are some strata of a fixed ratio of silicon oxide to metal oxide are minimal and small amounts of phosphorus, boron and / or aluminum are dispersed in the coating when using compounds. containing these elements as accelerators to increase coating deposition speed and control coating morphology.

The invention further relates to a vapor coating composition having a silicon-containing precursor having the structural formula.

R2

Mod. 71 20,000 and «. - 92/12

I

R3 - Si - 0 - Ri r₄ wherein R1 is selected from groups including alkyl and alkenyl. Rs is a functional group which gives the silicon compound the ability to be easily converted to silicon oxide and includes hydrogen, halogen, alkenyl radicals and alkyl halogenate. R3 is a bridging group to provide compounds with multiple silicon atoms and includes -S- and -N- groups. R2 completes the bonding of the central silicon atom.

The invention also relates to a coating composition having mixed metal containing precursors; P; ex. tin and silicon-containing precursors. The silicon metal precursor may include compounds containing -Si-O described above and an accelerator capable of enhancing the reaction rate of the coating compounds. Accelerators include Lewis acids and Lewis bases.

BRIEF DESCRIPTION OF DRAWINGS

Figure 1 illustrates a coated substrate incorporating features of the invention and obtained using the inventive coating apparatus, methods and materials.

Figure 2 is a vertical projection of a coating system having two coating positions, one of which includes a coating apparatus having multiple coating zones incorporating features of the invention.

Figure 3 is a similar perspective to that of

Figure 2 shows a coating apparatus having a coating zone incorporating features of the invention.

Mod. 71 20,000 ex. · 92/12

Figure 4 is a graph showing a coating gradient and an extended and improved coating gradient deposited in accordance with the teachings of the invention.

Figure 5 is a graph showing the effect of the height of the coating apparatus from the surface of a glass substrate and the conveyor flow on the ratio of silicon oxide to tin oxide in the coating deposited on the glass substrate. according to the teachings of the invention.

Figure 6 is a graph showing the effect on film thickness using the accelerators of the present invention. .....

DESCRIPTION OF EMBODIMENTS

Mod. 71 20,000 and *. 92/12

Referring to Figure 1, there is shown a coated article 10 incorporating features of the invention that can be produced using the inventive coating apparatus, processes and materials. In general, article 10 includes a substrate 12, e.g. ex. but not limited to the invention, clear or colored plastic and / or glass having a coating (14) which exhibits a minimum of reflected color by having a continuously varying refractive index and preferably having a lower emissivity than the uncoated substrate. . In the following discussion the substrate is a glass substrate. Coating (14) is generally composed of a mixture of silicon oxide and metal oxide such as tin oxide. As in the Zaromb patent discussed above, the coating 14 has a continuously changing composition as the distance to the glass-coating interface 16 increases. Generally, near the glass-coating interface (16), the coating is predominantly silicon oxide whereas on the opposite surface (18) of the coating (14), e.g. ex. the surface of the coating furthest from the glass coating interface (16), the coating composition is predominantly tin oxide. The predominantly tin oxide region may continue to be predominantly tin oxide by a thickness required by the use of the article. For example, when you want an article having a high emissivity, e.g. ex. with an emissivity close to that of the glass substrate, the predominantly tin oxide region is thin; when an article having a low emissivity is desired, the predominantly tin oxide region is thicker. The tin oxide region may be doped with fluoride or antimony as taught in U.S. Pat. 3,677,814, to further reduce emissivity. Between glass-facing interface35

Mod. 71 20,000 and <. 92 (16) and the opposite surface (1B), the coating (14) is composed of amounts of silicon oxide and tin oxide continuously varying as the distance to the glass-coating interface 16 increases. In other words, as the distance to the glass-coating interface 16 increases, each region of the continuously changing composition of the coating 14 contains a weight ratio of tin oxide to silicon oxide different from the preceding region and despite moreover not limiting the invention, usually this ratio tends to increase as the distance to the viclro-coating interface 16 increases. The opposite surface 18 is predominantly tin oxide, ie, the weight percent silicon oxide in the furthest region approaches zero and the weight percent tin oxide approaches 100.

Although coating 14 has been discussed using a tin oxide coating, the invention is not limited thereto and, as will be appreciated from the discussion below, any two or more metal oxides may be used in the practice of the invention. .

The coated article (10) of Figure 1 was produced using the coating system (19) shown in Figure 2. A discussion of the coating apparatus (20) in Figure 3 will now be presented for a better presentation of the characteristics of the coating system. coating (19) shown in Figure 2. The apparatus (20) of Figure 3 may be used to deposit an inhomogeneous coating of the type discussed above above onto the substrate— (12). In Figure 3 as in Figure 2, the substrate (12) is a strip of glass (22) or pieces cut from it.

Referring to Figure 3, the coating apparatus 20 is conveniently supported in

Mod. 71 · 20,000 and '. 92/12 above and away from the glass strip (22) supported in a molten metal pool or bath (24) contained in a chamber having a non-oxidizing atmosphere, not shown, e.g. ex. of the camera type shown in US Patent No. 4,853,257 whose teachings are incorporated herein by reference. As shown in Figure 3, the glass strip 22 moves from left to right under the cladding apparatus 20, e.g. ex. through a coating position. As will be appreciated the invention is not limited to the chamber, not shown, contained in the pool or molten metal bath, or to a non-oxidizing atmosphere, and any chamber design having any type of atmosphere may be used in the practice of the invention. Another method for moving a heated substrate by passing a coating apparatus embodying features of the invention.

In general and not limited to the invention, strip 22 has a thickness range of from about 0.002 to about 0.013 meters (0.08 inches to about 0.50 inches) and moves at speeds of about 17.08 meters at about 2.54 meters (about 700 to about 100 inches) per minute respectively. The molten tin bath 24 has a temperature in the range from about 538 ° C (1000 ° F) to about 1094 ° C (2000 ° F).

The apparatus (20) includes an elongate liner unit (25), two elongate muffs (28) and (26), either side of the liner unit (25), and two elongate discharge units (31) and (32). ), one on each outer side of an exhaust as shown in Figure 3 ......... The elongated term as used herein means that the coating unit, exhaust and exhaust units extend across the width of the groove. , ie, transverse to the movement of the strip (22). Discharge units 31 and 32 provide an inert gas curtain to prevent

Mod. 71 · 20,000 ex. · 92/12 coating vapors from the coating zone, ie the zone between the discharge units (31) and (32), move into the atmosphere chamber and also to prevent the atmosphere chamber from moving into the atmosphere. coating zone. As can be appreciated the separation between the coating zone and the atmosphere chamber is required due to the atmosphere in the coating zone, as will be discussed, to be an oxidizing atmosphere and the atmosphere chamber, as discussed above, to be a non-oxidizing atmosphere. In the practice of the invention, the inert gas is nitrogen.

Exhaust pipes 26 and 28 according to the teachings of the invention are not equally spaced from the lining unit 25. More particularly, with the glass strip moving from left to right as shown in Figure 3, the exhaust (28) is closer to the coating unit (25) than the exhaust (26). By positioning the leaks at different distances from the coating unit the coating vapors are in contact with the strip surface for different periods of time. Consequently, keeping all other parameters, e.g. eg glass temperature, space between the coating unit and the glass strip surface and exhaust pressures, a thicker coating will be deposited on the strip as it passes between the exhaust (26) and the coating unit (25) than between the liner unit (25) and the exhaust (28). This feature of the invention will be more fully appreciated in the discussion of the coating system 19 shown in Figure 2.

As can now be appreciated, the design of the discharge units 31 and 32, the exhausts 26 and 28 and the coating unit 25 are not limiting of the invention. The invention has been practiced using the exhausts 26 and 28 with an elongated aperture 36 attached to a chamber

Mod. 71 · 20,000 ex. 92/12 and using the discharge units (31) and (32) with an elongated opening (50) connected to a discharge chamber (46). The inert gas has uniform pressure and constant velocity along the length of the opening (50) to provide an inert gas curtain, a portion that flows into the atmosphere chamber (not shown), and a portion towards the exhaust (26). and (28) adjacent as shown in Figure 3.

The coating unit (25) includes a discharge chamber (56). The coating vapor exits the chamber (56) through the elongated opening (58) and is oriented towards the surface of the glass strip (22) passing under the opening (58). 0 liner vapor has a uniform pressure and constant velocity across the length of the opening 58 and is sufficiently pressure to allow a portion of the steam liner to flow upstream and a portion to flow downstream as shown in Figure 3.

The amount of nitrogen typically introduced by each discharge unit (31) and (32) is in the range of about 0.0095 to 0.1415 cubic meters per second (from 20 to about 300 standard cubic feet per minute) for a strip having a width of about 4.06 meters (160 inches). As can be appreciated the rate of nitrogen flow is not limiting of the invention; however, it should be sufficient to provide an inert curtain separating the coating zone from the atmosphere chamber.

Exhaust ports (36) (26) and (28) and exhaust pressure are adjusted to exhaust a portion of the inert gas from adjacent discharge units (31) and (32), respectively, and a portion of the coating steam of the coating unit (25). As shown in Figure 3 and as discussed above, the exhaust (26) is further away from the liner unit (25) than the exhaust (28). With this arrangement and keeping the exhaust pressure constant for each exhaust unit, the residence time of the coating vapor is longer for the glass strip (22) as it moves from the exhaust (26) towards the coating unit. (25) than to the glass strip as it moves from the coating unit (25) towards the exhaust (28).

Mod. 71 - 20,000 ex. · 92/12

Although the above asymmetric arrangement is preferred because of its simplicity, it is not intended to limit the invention since the finding contained herein is that different coating steam residence times on different sides of a coating unit alter the final composition of the coating. Accordingly, other suitable apparatus or processes may be used to achieve such an effect. It has been found that the same effect achieved with asymmetrically arranged leaks, as discussed above, can also be achieved even with symmetrical spacing of the liner unit (25) and the leaks, for example by adjusting the height or level of the openings ( 36) of the exhaust (26) and (28) relative to each other and to the glass strip. Another method for varying the residence time of the coating vapor is to vary the ratio of exhaust flow (26) to exhaust (28).

By way of illustration only, where the spacing between the liner unit (25) and the exhaust (26) -e (-28) - is symmetrical, reducing the exhaust pressure (26) below the exhaust pressure ( 28) results in the residence time between the coating unit (25) and the exhaust (26) being greater than the residence time between the coating unit (25) and the exhaust (28).

Referring now to Figure 2, the coating system (19) was used to apply the coating (14) to the coated article (10) shown in Figure 1.0.

Mod. 71 - 20,000 and «. 92/12 coating system (19) includes a coating position (59) for applying a graded composition coating and a coating position (60) to extend the thickness of the predominantly tin oxide region on the surface (18) of the coating. liner (14) (see Figure 1). The liner position (59) includes liner units (61), (62) and (64), exhaust (66), (68), (70) and (72) and discharge units (31) and (32) . The coating position (60) is not limiting of the invention; however the coating position used in the practice of the invention was of the type of coating apparatus disclosed in US Patent No. 2. No. 4,853,257, the teachings of which are incorporated herein by reference. The opening (50) of the discharge unit (31) is about 0.635 meters (25 inches) from the opening (50) of the discharge unit (32); the exhaust opening (74) (66) is about 0.57 meters (22-1 / 2 inches) away from the discharge unit opening (50) (32); the opening (76) of the casing unit (61) is about 0.51 meters (20) inches apart from the opening 50 of the discharge unit (32); the exhaust opening (78) (68) is about 0.445 meters (17-1 / 2 inches) away from the opening (50) of the discharge unit (32); opening (80) of the discharge unit (62) meters (12-1 / 2 inches) of the discharge (32); the opening (82) is about 0.32 away from the exhaust unit (70) about 0.254 meters (10 inches) away from the opening (50) of the discharge unit (32); the ..... opening (84) of the casing unit (64) is about 0.127 meters (5 inches) from the opening (50) of the exhaust unit (32) and the opening (86) of the exhaust (72) ) is about 0.06 meters (2-1 / 2 inches) from the opening (50) of the discharge unit (32). Coating position (60) is spaced apart

Mod. 71 20,000 and «. · 92/12 about 1 meter (6 feet) from the discharge unit (32).

The openings 50, 74, 76, 78, 78, 80, 82, 82, 84 and 86 are conveniently about 0.0051 meters apart. 2 inches) above the upper surface of the glass strip (22) as shown in Figure 2. The length of the openings (50) was about 0.64 meters (25) inches); the length of apertures 74, 78, 82 and 86 were about 0.64 meters (25 inches) and the length of apertures 76, 80 and 84 were about 0.5334 meters (21 inches). The width of the openings (50) was about 0.0032 meters (0.125 inches); the width of the apertures (74), (78), (82) and (86) was about 0.0064 meters (0.250 inches) and the width of the apertures (76), (80) and (84) were about 0.0015 meters (0.06 inches). Nitrogen and coating vapor flows were about 0.0058 m³/ s 0.0117 m³/ s (350 to 700 SLPM standard liters per minute). The exhaust flow was about 0.0059 m³/ s 0.01283 m³/ s (375 to about 770 SLPM). The speeds of the glass strip were about 5.08-17.78 meters (200-700 inches), the temperature of the glass strip moving in, through or out of the coating positions (59) and (60). ) were between about 635-675 ° C (1170-12502F).

coating system (19) and in particular the coating position (59) and the associated method are especially effective for chemical vapor deposition (DQV) of coating of silicon and metal-containing precursor mixtures to provide the article from Figure 1 ........ ............-...................................

In the following discussion, coating 14 is made from a mixture of tin-containing precursors and silicon-containing precursors capable of volatilization.

Mod. 71 · 20,000 ex. · 92/12 and converted to the corresponding oxides in the presence of oxygen at temperatures ranging from about 400 ° C to about 815 ° C (750 to about 1500 ° F). As will be appreciated the invention is not limited thereto and other precursors may be used with the coating apparatus and coating process discussed above.

Examples of silicon compounds which may be used in the practice of the invention include, but are not limited to, tetraethoxysilane, silane, diethylsilane, di-t-butoxydiacetoxysilane and the silicon compounds disclosed in US Patent No. 2. 3,378,396, issued to Zaromb, and U.S. Patent Nos. 4,187,336, 4,308,316, 4,377,613,

4,419,386, 4,206,252, 4,440,822 and 4,366,117, which are incorporated herein by reference.

Compounds that have been used in the practice of the invention include diethylsilane, tetramethoxysilane, tetraethoxysilane, tetraisopropoxysilane, diethyldichlorosilane, tetramethyl cyclotetrasiloxane and triethoxysilane.

In addition to the silicon-containing precursors discussed above, the invention contemplates silicon-containing precursors that can be converted to their corresponding silicon oxides and can be used in admixture with the metal-containing precursors to form the desired coating on the substrate, e.g. glass having a coating of the desired mixed oxide gradient.

When looking for a silicon-containing precursor to form a silicon oxide coating, one of ordinary skill in the art would not normally choose a precursor having a Si-0 bond because it is one of nature's most difficult to break bonds, as evidenced by the stability of the mineral bond. Si-0 quartz (SiOs). Therefore breaking it into the precursor and rearranging it into a mesh of webs containing them for a coating is difficult, e.g. The siloxane bond requires high temperature and / or long periods of time to form a corresponding silicon oxide coating. For this reason one skilled in the art does not expect silicon-containing precursors having the siloxane structure to be useful in moving substrate.

However, it was determined that if a silicon in a compound with a Si-0 bond also had at least one specific functional group, the reactivity of the precursor containing

Mod. 71 · 20,000 βχ. - 92/12 silicon having velocity of even if the Si-0 bond, and consequently its coating formation, would be increased, any appreciable change in its behavior capable of giving the silicon-containing precursor are a Si-0 bond, The ability to easily convert silicon oxide-containing coatings include hydrogen, halogens, vinyls and C1-chlorinated alkyls. Reactivity in one of the silicon-containing precursor may be determined by the appropriate choice of functional groups. The silicon-containing precursor of the present invention is not limited to having only the aforementioned substituents on it. Provided one or more of the above defined functional groups is present in the silicon-containing precursor having the bond

Si-O may also include other groups such as alkyls and other substituents without significant detrimental effect on the overall reactivity of the silicon-containing precursor.

Mod. 71 · 20,000 and '. · 92/12 by reference to the following structural formula I.

I

Frog

I

I

R3 — Si-O-Ri t

I

R4 wherein R1 is selected from the following Group A consisting of compounds which must not have an available oxygen to form the peroxide bond:

alkyl or substituted alkyl radicals having from 1 to 10, preferably 1 to 4, carbon atoms, such as -CHs, -CH 2 CH 2 CH 3 and -CH 2 CH 2 OH;

halogenated or perhalogenated alkyl radicals having from 1 to 10, preferably 1 to 4 carbon atoms, such as -CCI3, -CH2CHCICH3 and

-CHaCCIaCCl3;

alkenyl or substituted alkenyl radicals having from 10 to 10, preferably 2 to 4, carbon atoms, such as -CH = CHCHs and -CH = CHa;

alkynyl or substituted alkynyl radicals having from 2 to 10, preferably 2 to 4 carbon atoms, such as -CHyCCHs, -C = CH; and aryl or aralkyl or substituted aryl or aralkyl radicals having from 6 to 11, preferably 6 to 9, carbon atoms, such as -ΟβΗε, -CeH4CH3;

wherein Ra are functional groups which form a bond to the Si atom which is easily thermally broken down, e.g. at temperatures between about 93.5 ° C - 445 ° C (200 ° F - BOO ° F) and preferably between about 205 ° C 370 ° C (400 ° F - 700 ° F). The functional group (R2) capable of giving the silicon-containing precursor the ability to be easily converted to silicon oxide coating is selected.

Mod. 71 20,000 and «. · 92/12 listed in group B consisting of:

halogen hydrogen, preferably Cl;

alkenyl or substituted alkenyl radicals as defined in Group A for R1;

haloalkyl or perhalogenated alkyl radicals and substituted alkyl or alkyl as defined in Group A for R1;

wherein R3 is a bridging group to provide compounds with multiple silicon atoms. R3 is selected from the group consisting of;

-N-Rs where Rs is an alkyl or substituted alkyl

I

I having from 1 to 10, preferably from 1 to 4 carbon atoms, such as -CH 2 CH 3 or -CH 2 CH 2 CH 3;

-N-;

I

I

-PH;

I f

-P-Rs where Ra is as defined above;

I

I

-Pπ

Wherein n is from 1 to 10, preferably from 1 to 4, and V / n wherein Ra completes the bond on the base silicon atom.

Mod. 71, 20,000 and ». - 92/12

FU is selected from Groups A and B above and from the following Group C consisting of:

carbon radicals such as -OCH 2 CH 3;

alkyl or substituted alkyl radicals having from 1 to 10, preferably from 1 to 5, carbon atoms, such as -CH 2 CH 3;

-CN;

-OCN, and

-PH2;

alkylphosphines and dialkylphosphines, in which alkyl radicals have from 1 to 10, preferably from 1 to 4, carbon atoms such as -PHCH3 and -P (CH₂CH3) 2;

Substitutes for Groups AB and D discussed above may be selected from the following group E consisting of:

alkoxide radicals having from 1 to 10, preferably from 1 to 4, carbon atoms, such as -OCH 2 CH 2 CH 2 CH 3;

an alkyl radical having from 1 to 10, preferably from 1 to 4, carbon atoms, such as -CH 2 CH 2 CH 3;

a halogen or halogenated alkyl radical having from 0 to 10, preferably from 0 to 4, carbon atoms, such as Cl or -CCl 3;

an alkenyl radical having from 2 to 10, preferably from 2 to 4, carbon atoms, such as -CH = CH 2;

an alkynyl radical having from 2 to 10, preferably from 2 to 4, carbon atoms, such as -C = CH;

an aryl or aralkyl radical having from 6 to 11,

preferably from 6 to 9 carbon atoms, such as -CsHs;

-CN;

-OCN;

phosphine, alkylphosphine and di-alkylphosphine radicals, wherein the alkyl group is from 1 to 10, preferably

Mod. 71 · 20,000 ex. From 1 to 4, carbon atoms, such as -PH2, -PHCHs -P (CH₂CH₃) 2, and -OH.

A variety of compounds may be formed from the backbone I. When a molecule having a single silicon atom is desired, R 3 may be selected from Groups A, B or D. When multiple silicon atom molecules are desired, R 3 may be selected. It is a bridging group. In the case of molecules with multiple silicon atoms, R3 directly bonds two silicon atoms. When molecules with multiple silicon atoms are cyclic, R <is not present on any of the silicon atoms. When molecules with multiple silicon atoms are linear or branched, R4 groups are present only at the terminally terminated silicon atoms in the chain. When molecules of more than two silicon atoms are desired, the bridging groups Ra may be the same or different.

Another type of bond is possible to create multiple silicon atom molecules with Si-O-Si bonds. In this case, R1 is no longer selected from Group A and is instead another silicon-containing group from the backbone I with the continuing requirement to have an R2 selected from Group B. The bond between the silicon-containing groups is chosen so that a direct Si-O-Si bond is formed. If a molecule with more than one silicon atom is desired. R4 is present only at terminal silicon atoms, —as described above, R3 can now be selected from groups A, B, C or D. Selected R3 from Group C can create multiple silicon atoms molecules with different bridging groups , ie Si-O-Si-N-Si.

Mod. 71 - 20,000 ex. - 92/12

As can be appreciated, single or complex silicon-containing precursors are possible. The only requirement remains that each silicon atom has directly attached to it an oxygen atom and a functional group selected from Group B.

Specific compounds that have been used in the practice of the invention include tetramethylcycloetetrasiloxane, tetramethyldisiloxane and triethoxysilane. Specific compounds which may be used in but not limited to the practice of the invention are methyldimethoxysilane, dimethylmethoxysilane, trimethoxysilane, dimethylchloro methoxysilane, methylchloro-dimethoxysilane, dichloro-dimethoxyethyl trimethoxylethoxylethoxysethane, , tetramethyldichloro disiloxane, tetramethyl cyclotetrasiloxane, triethoxysilane, chloro triethoxysilane, pentachlorethyltriethoxysilane and vinyl triethoxysilane.

Metal-containing precursors which may be used in admixture with the silicon-containing precursors defined above, in the chemical vapor deposition of mixed oxides on a glass substrate, include metal-containing precursors which vaporize at or below about 500 ° C (260 ° C). ) and which will react with an oxygen-containing gas to form the corresponding metal oxides. Preferably, but not limited to the invention, compounds which may be used include metal-containing organometallic compounds including, but not limited to, titanium, vanadium, chromium,

- ....... manganese, ...... iron, cobalt, nickel, copper, zinc, gallium ', 30 gremanium, arsenic, selenium, itrio, zirconium, niobium, molybdenum, cadmium, rhodium, ruthenium, palladium, indium, antimory, tellurium, tantalum, tungsten, platinum, lead, bismuth, aluminum and tin, of these metal compounds, tin compounds are preferred. Examples of tin compounds which may be used herein include those defined by the following structural formula II.

II

Mod. 71 - 20,000 and «. · 92/12

Rz

I

I

Rs-sn-rs

I

I

Wherein R, R v, Ra and R 9 are the same or different and include, but are not limited to, halogens, preferably Cl or F, and an alkyl radical having from 1 to 10, preferably 1 to 4, preferably 6 to 9 , carbon atoms such as -CeHB. In the practice of the invention any other organic or inorganic functional group may be used provided that the absolute vapor pressure of the resulting compound is at least 68.95 Pa (0.01 pounds per square inch) below about 260 ° C (500 ° F ).

The silicon-containing precursors described above, including those containing the Si-0 bond, may be used alone or may be used in admixture with the organometallic compounds discussed above in the chemical vapor deposition of the corresponding single oxides or mixed on a glass substrate. . However, when using silicon-containing precursors alone, or mixed with other metal-containing precursors, in the chemical deposition of single oxide vapor or mixed onto a moving substrate, eg a glass band progressing through a bath. molten metal or on a carrier, it is desirable to have a silicon oxide deposition rate sufficient to coat the glass substrate on

Mod. 71 · 20,000 ei. 92/12 movement. For example, when a progressing glass strip is coated and the silicon oxide deposition rate is relatively low, the glass strip speed must be reduced. More particularly, for

By depositing a coating of about 1.2 x 10-6 m (1200 A) thick on a moving glass strip at a linear velocity of more than about 7.62 meters (30C inches) per minute, Deposition velocity of all classes of silicon-containing precursors used in chemical vapor deposition processes must be increased to achieve a uniform coating.

Various materials that can be used to accelerate silicon oxide deposition from their precursors have been identified. The type and functionality of each accelerator depends to some extent on the silicon-containing precursors with which they are used. Combinations were determined for a specific coated article and for the processes used to deposit the desired coating, in particular the mixed oxide of the invention. It has further been determined that a synergistic effect occurs between certain combinations of precursors and accelerators which results in beneficial change and control of coating morphology.

Accelerators that can be used in the practice of the invention to increase the deposition rate of silicon oxide alone or in combination with another oxide, for example tin oxide, can be defined as follows:

(1) Lewis acids, such as trufluoroacetic acid

- co and hydrochloric acid. ^_ ......

(2) Lewis bases such as NaOH, NaF, CH3OH, CH3OCH3 and S (CH₃CH2) 2.

(3) Water.

(4) Nitrogen, phosphorus, boron and sulfur compounds containing the following structural formulas.

THE-.

Mod. 71 · 20,000 ex. · 92/12 (a)

Rn l

I

R10-Y-R12, (b)

Rn (I

R10-S-R12

I t

R13, (c)

R10-S-R11 (d)

Rn

I (

Rio-P-0

I

Rx2 and (e)

Rll R14 \ /

R10-P-R12

»

R 13 wherein Y is selected from the group consisting of nitrogen, boron and phosphorus and R 1, R 11, R 12, R 13 and R 11 are selected from the following list of functional groups, which is referred to as Group F:

hydrogen;

Mod. 71 · 20,000 ex. Halogen, preferably Cl;

alkenyl or substituted alkenyl radicals having from 2 to 10, preferably from 2 to 4, carbon atoms, such as -CH = CHa;

substituted alkyl or perhalogenated alkyl radicals having from 1 to 10, preferably from 1 to 4, carbon atoms such as -CCIHz or substituted alkyl or halogenated alkyl radicals having from 1 to 10, preferably from 1 to 4, carbon atoms such as as -CCI2CH2CH3;

acyloxide radicals having from 1 to 10, preferably from 1 to 4, carbon atoms such as -OCOCH 3;

alkynyl or substituted alkynyl radicals having from 2 to 10, preferably from 2 to 4, carbon atoms such as -C = CH;

alkyl or substituted alkyl radicals having from 1 to 10, preferably from 1 to 4, carbon atoms such as -CH 3, -CH 2 CH 2 CH 3;

aryl or substituted aryl radicals having from 6 to 10, preferably from 6 to 9, carbon atoms such as -CHsHaCHs;

alkoxide or substituted alkoxide radicals having from 1 to 10, preferably from 1 to 4, carbon atoms such as -OCH 2 CH 2 CH 3;

wherein said substituents are from Group E discussed above, examples of such compounds include, but are not limited to, triethosphite, trimethylphosphite, trimethylborate, PFs, PCI3, PBr3, PCIb, BCI3, BF3, (CH3) 2BBr, SF3 and HO3SF . In the practice of the invention triethylphosphite was used.

(5) Aluminum compounds having the following structural formula III may be used to accelerate the rate of deposition of silicon-containing precursors alone or in combination with other metal-containing precursors (the other metal-containing precursors, as may be appreciated, do not include aluminum-containing precursors):

III

R15

I

I

R1T-A1-R16

Mod. 71 - 20,000 ex. 92/12 wherein Ris, Ris and Rit are the same or different and are selected from the following Group G: hydrogen;

halogens, preferably Cl;

-O-R17 wherein Rxt is a straight or branched substituted alkyl radical having from 1 to 10 carbon atoms, preferably from 1 to 4, with substituents selected from Group E above; -S-Ris, where Ris is equivalent to Rit as defined above;

-NHs;

-R19-O-R20 wherein Ris and R20 are straight or branched alkyl groups or substituted alkyl groups having from 1 to 10, preferably from 1 to 4, carbon atoms with substituents selected from Group E discussed above; (minus phosphine groups such as -PH2); and

-N-R21, wherein R21 forms a cyclic group having from 2 to 10, preferably from 2 to 6, carbon atoms with substituents selected from Group E discussed above (minus phosphine groups).

(6) Ozone. The mechanism that drives the accelerators of the invention to increase the deposition rate is not completely understood. Even though the mechanism is not fully understood, the results discussed above demonstrate.

Mod. 71 · 20,000 and '. It is clear that the deposition rate of the mixed oxide coating has been increased. Referring to Table 2 in Example I below, Series Nos. 11 and 12 have the triethylphosphite accelerator. The deposition speed of the silicon oxide coating was at least twice the speed of the non-accelerated NQ2 Series silicon oxide coating.

A moving glass substrate was coated using the same precursor chemistry as Series NQs 11 and 12 of Table 2 and resulted in similar deposition rates. The precursors were sprayed at a temperature of about 65 ° C (150 ° F) to about 260 ° C (500 ° F), and the gaseous mixture of the precursors, oxygen containing gases, and carrier and accelerator gas was contacted with the glass strip is supported over a molten metal bath and heated to a temperature of about 510 ° C (950 ° F) to about 730 ° C (1350 ° F). The glass strip advanced at a speed of about 4.25 to 18.00 meters (170 to 730 inches) per minute.

The amounts of the components which may be used in the practice of the invention are defined in Table 1.

Table 1

Pei ^ entafifimJflQlar

Compound Extended Range Preferred Range

Containing Precursor—

<td>Metal</td><td> 0,005</td><td>The</td><td> 5,0</td><td> 0,1</td><td>The</td><td> 2,0</td>

<td>Precursor Containing</td><td></td><td></td><td></td><td></td><td></td><td></td>

<td>Silicon</td><td> 0,0001</td><td>The</td><td> 5,0</td><td> 0,05</td><td>The</td><td> 2,0</td>

<td>Gas Containing Oxygen</td><td> 1,0</td><td>The</td><td> 99,0</td><td> 5,0</td><td>The</td><td> 50,0</td>

<td>Accelerator</td><td> 0,0001</td><td>The</td><td> 10,00</td><td> 0,01</td><td>The</td><td> 2,0</td>

Mod. 71 · 20,000 ex. - 92/12

When substrate (12) (see Figure 1), e.g. glass substrate, is subjected to chemical vapor deposition of mixed oxides, for example a mixture of silicon oxide and tin oxide, to obtain a coating (14) thereon according to the process of the invention, the coating the coating (14), as discussed above, is characterized in that it has a continuously varying composition as the distance to the glass-coating interface (16) increases, resulting in a substantial reduction of iridescence in the coated product. Assuming a coating substantially composed of silicon oxide and tin oxide, the portion of the coating adjacent to the glass-coating interface (16) is mostly composed of silicon oxide and as the distance to the glass-coating composition increases. , each successive region of the continuously varying composition contains a ratio of silicon oxide to tin oxide that varies as the glass-coating interface increases. More particularly, the percentage of silicon oxide decreases as the percentage of tin oxide increases, so that as the opposite surface (18) is reached, the region is predominantly composed of tin oxide. Accordingly, the thickness of the predominantly tin oxide region may be increased to reduce the emissivity of the coated article.

When the chemical vapor deposition of mixed oxides on a glass substrate is determined by the addition of one or more of the accelerators of the present invention, e.g.^-Of phosphorus, aluminum or boron, a small amount of the base atom, e.g. phosphorus, aluminum or boron, is dispersed in the coating (14). The presence of phosphorus, aluminum and / or boron in the coating affects the morphology of the resulting coating so that the continuously varying components mentioned above are less likely to form discrete composition strata, e.g. layers having a fixed ratio of silicon oxide to tin oxide for thicknesses greater than 7 x 10-8 m (70 A). In addition, the presence of phosphorus, aluminum and / or boron affects the morphology of the resulting coating by decreasing the percent crystallinity (approaching 0% crystallinity) and thereby reducing the light scattering properties that can be observed as mist. The amount of phosphorus, aluminum and / or boron compound incorporated in the layer is a function of the process variables.

a strip of glass was coated in

In the practice of the invention, movement at speeds between 4.25 to 18 meters (175 and 730 inches) per minute and

637 ° C (180 ° F) at

Mod. 21 20,000 ex. 92/12 having a temperature in the range of (1220 ° F) with a gas mixture having a ro compound as an accelerator; the molar fraction of

0.01 to 0.5. It was found dispersed in the

660 ° C Phosphor Accelerator Coating An invention includes atomic percent phosphorus from 1 to 12.

use an amount of accelerator greater than 0 and up to 15 atomic percentage with a preferred range of 1 to 5 atomic percentage.

The present invention will be better appreciated and understood as follows:

from the description of specific examples that

Example-J.

Various compositions were prepared from precursors containing silicon and monobutyltin chloride to illustrate the increased deposition rate of mixed oxide films on a glass substrate according to the teachings of the invention. In each composition, monobutyltin chloride with different silicon-containing precursors was used. The precursors were sprayed as necessary and the gaseous mixture of precursor resul35.¹⁰ • 1 ί

Mod. 71 - 20,000 ex. Oxygen and nitrogen was introduced into a quartz tube that was electrically heated and controlled to maintain the temperature at 150 ° C (300 ° F). The concentration of the silicon-containing precursors was in all cases 0.30 molar percent, monobutyltin chloride had a molar percent 0.50, oxygen a molar percent 21, the remainder being nitrogen. The velocity of the precursors and the carrier gas was maintained at a rate of 30 centimeters per second in the quartz tube. This gas mixture was passed over a heated glass substrate at about 650 ° C (1200 ° F) for 3 to 30 seconds after which the consumed gas mixture was poured into a chemical hood. Film thickness was measured for all series except Series NQ. 8, discussed below, using a Tencor Pl. Film deposition rate was calculated by dividing the film thickness by the coating time. The data obtained are presented in Table 2 below.

z^: i

JS2 Series,

Precursors

Deposition Speed

Mod. 71 - 20,000 ex. 92/12

Containing Silicon or .CAZSecond).

mZs

<td> 1</td><td>diethylsilane</td><td> (129)</td><td>1.29x1o^-7</td>

<td> 2</td><td>tetraethoxysilane</td><td> (43)</td><td>4.3x10 ~ e</td>

<td> 3</td><td>di-t-butoxydiacetosilane</td><td> (64)</td><td>6.4x10^-and</td>

<td> 4</td><td>tetramethyl-cyclo- -tetrasiloxane</td><td> (181)</td><td>1.81x10^-7</td>

<td> 5</td><td>tetramethyl-cyclo- -tetrasiloxane</td><td> (205)</td><td>2.05x10^-7</td>

<td> 6</td><td>tetramethyl-cyclo- -tetrasiloxane</td><td> (177)</td><td>1.77x10-7</td>

<td> 7</td><td>tetramethyldisiloxane</td><td> (164)</td><td>1.64x10-7</td>

<td> 8</td><td>ethyltriacetosilane</td><td> (110* &gt;</td><td>1.10x10-7</td>

<td> 9</td><td>triethoxysilane</td><td> (139)</td><td>1.35x10-7</td>

<td> 10</td><td>methyldiacetoxysilane</td><td> (32)</td><td>3.2x10-®</td>

<td> 11</td><td>tetraetosisilane + 0.31, molar percentage triethylphosphite</td><td> (136)</td><td>1.36x10-7</td>

<td> 12</td><td>tetraethoxysilane + 0.09 mol percent triethylphosphite</td><td> (87)</td><td>8.7x10^-and</td>

estimated

The NQ Series. 1 was used as a control because diethylisilane is generally accepted as having an acceptable deposition rate.

THE

Mod. 71 20,000 and «. · 92/12

The tetramethyl cyclo tetrasiloxane precursors used in the NQ Series. 4, 5 and 6 were obtained from different suppliers. The NQ Series. 2, 3 and 10, using silicon-containing precursors having a Si-0 bond without the accelerators or functional groups of the present invention, had an expected low deposition rate. Series 4, 5, 6, 7 and 9 which had a Si-0 bond with the functional group of the present invention had a deposition rate equal to or better than that of the Series N2 control. 1. Additionally, the N2 Series. 2 when added with an accelerator as taught in the present invention (see Series No. 11 and 12) exhibited a higher deposition rate than Series No. 2. 2 and approaching (Series NQ. 12) or exceeding (Series N2. 11) control deposition speed, Series N2. 1.

The N2 Series. 8 is a compound having the Si-O bond that does not contain a functional group or accelerator of the present invention; however it shows a deposition speed equal to the control, Series N2. 1. The amount of N2 Series film. 8 was extremely poor and the film thickness had to be estimated using interference colors which was different from the measurement technique used for the NQ Series. 1-7 and 9-12.

Example 11

Two Series were performed showing the advantages obtained using an asymmetric coater configuration of the present invention rather than a symmetrical coater configuration. Referring to Figure 3, in a series the exhausts 26 and 28 have been positioned relative to the

Mod. 71 · 20,000 and '. 92/12 lining unit (25) so that x / y = 2 where x is the distance between the exhaust (28) and the lining unit (25) and y is the distance between the lining unit (25) and the while in another embodiment, the exhausts 26 and 28 have been positioned relative to the casing unit 25 such that x / y = 1. 0 The vapor of the coating composition was maintained at 166 ° C (337 ° F) and contained a molar percentage of 1.2 monobutyltin chloride, a molar percentage of 0.3 tetraethoxysilane, a molar percentage of 0.5 of triethylphosphite, a molar percentage of 1.0, a molar percentage of oxygen and the remainder of nitrogen. The floating glass strip of soda-lime silica supported by, and moving through, a molten metal bath had a thickness of about 0.003 meters (0.118 inches), a temperature of about 650 ° C (1200 ° F ) and a linear speed of about 13 meters (510 inches) per minute. The surface of the nitrogen curtain openings provided by the discharge units (31) and (32) and the exhaust (26) and (28) was maintained at a height of about 0.0055 meters (0.22 inches) above the surface of the glass strip (2) to be coated.

Tin depth profile of a film produced on the glass strip using both asymmetric and symmetric coater configurations is shown in the graph of Figure 4. Film analysis was performed using the Rutherford Backscattering Spectrometry, RBS) for the purpose of comparing the film gradient produced by the two coater configurations. 0 The RBS spectrum in Figure 4 was taken at a special angle to obtain the optimal depth resolution of the tin atom distribution across the film.

A comparison of the asymmetric coater configuration (shown by the solid line 210) with the symmetric coater configuration (shown by the dashed line 212) is shown in the RBS spectrum. 210 and 212 is the extended region of the tin signal of

3.24 x 10^_13J (2025 keV) at 3.7 relative counts up to 3.028 x 10^-13J (1890 keV) at 1.4 relative counts compared to symmetrical coater which has its tin signal ranging from 3.24 x 10¹³J (2025 keV) at 3.6

<img file="PT101462B_D0001.tif" />

relative counts up to 3,108 x 10¹³J (1940 keV) at 1.4 relative counts. This difference shows an increase in film thickness for an asymmetric coater configuration. As can be seen from Figure 4, the asymmetric coater configuration provides the revesMod gradient. 71 - 20,000 and «. · 92/12 with a long range of composition to vary.

Example III

A series of series was made using the casing apparatus 20 of Figure 3 where the exhausts 26 and 28 were positioned relative to the casing apparatus 20 so that x / y = 1. The vapor of the coating composition was maintained at 165 ° C (320 ° F) and contained a molar percentage of 0.8 monobutyltin chloride, a molar percentage of 0.3 tetraethoxysilane, a molar percentage of 0.1 triethylphosphite. , a molar percentage of 0.54 water and the rest air. 0 Total air flow and liner height were varied while maintaining constant concentrations. The results obtained are presented in the process profile diagram in Figure 5. Changing the height of the liner in inches and the conveyor flow in standard liters per minute, the boundary layer conditions are changed in the liner zone thereby changing the relative oxide ratio of tin and silicon oxide deposited. 0 The process profile diagram shows how these two liner height and volumetric feed change the techniques ie

coating composition on the glass substrate.

¹⁰

Λ

As shown in Figure 5, increasing the conveyor flow to a given height of the coating unit increases the ratio of tin oxide to silicon oxide. In other words, the weight percent of tin oxide increases as the weight percent of silicon oxide decreases. By raising the height of the coating unit to a given decrease in conveyor flow, the ratio of tin oxide to silicon oxide, ie the weight percent tin oxide decreases as the weight percent silicon oxide increases.

Mod. 71 · 20,000 ex. - 92/12

Example IV

Several series have been performed to show the effects of water and triethylphosphite on the thickness of the mixed oxide film for a constant vapor residence time. The process diagram, Figure 6, was developed using experimental design data. The casing unit (25) shown in Figure 3 was used with the exhausts (26) and (28) positioned relative to the casing unit (25) such that x / y = 1. 0 The precursor vapor was maintained at 165 ° C (320 ° F) and contained a molar percentage of 0.8 monobutyltin chloride and a molar percentage of 0.3 tetraethoxysilane. Triethylphosphite (TEF) and water were varied and sufficient air was added to obtain a standard 500 liter feed rate per minute. Glass strip 22 had a thickness of 0.003 meters (0.118 inches), a temperature of 650 ° C (1200 ° F) and a linear velocity of 13 meters (510 inches) per. minute. The coating unit (25) was kept at a height of

0.0055 meters (0.22 inches) above the surface of the glass strip. Note the substantial effect exhibited by the presence of triethylphosphite on the thickness of the coating. As the molar percentage of triethylphosphite increases the coating thickness increases. Increasing the molar percentage of water also increases the thickness of the coating.

<img file="PT101462B_D0002.tif" />

10, A.

Mod. 71 - 20,000 ex. 92/12 article (12) of Figure 1 was produced using the coating position (59) shown in Figure 2 in conjunction with the coating position (60) described in Henery's teachings. Coated articles up to three coating thicknesses were produced, ie at three different speeds of the glass strip to demonstrate process flexibility. Coating position (59) was used to produce a coating that varied in predominantly silicon oxide composition at the glass coating interface (16) to predominantly pure tin oxide and coating position (60) produced a predominantly extended thickness. of tin oxide.

The casing position (59) had three casing units (61), (62) and (64) with openings (76), (80) and (84), respectively, and four exhausts (66), (68), (70) and (72). The exhausts 66 and 68 have been positioned relative to the liner unit 61 in a symmetrical configuration while the exhausts 68 and 70 and the exhausts 70 and 72 have been arranged in an asymmetrical configuration around the coating units (62) and (64). Additionally, the lining position (59) had two discharge units (31) and (32) each with an opening (50). The distance between apertures 74 and 76, 76 and 78, 78 and 80 and 82 and 84 and 86 was about 0.0708.₁ meters (2-3 / 4 inches). The distance between openings 80 and 78 and between 84 and 82 was about 0.14 meters (5-1 / 2 inches).

To effect the desired change in coating composition, different chemical feed rate ranges are required in each of the coating units 61, 62 and 64. The chemical concentrations required to produce the desired composition change are still a function of the glass strip velocity. Examples of fixed points are given in Table 3. In each of these cases the carrier gas was air maintained at a

Mod. 71. 20,000 ex. - 92/12 temperature of about 165 ° C (320 ° F). The total gas flow from the discharge units 31 and 32 was maintained at about 500 standard liters per minute. The coating position (59) was moved about 0.0059 meters (0.22 inches) above the moving glass strip (22). The predominantly tin oxide extended region was deposited at the coating position (60) using the teachings of U.S. Pat. 4,853,257.

The equation (γ a *² + b *²) commonly used by those skilled in the art to quantify color observation of an object is discussed by Hunter in Ford Technology. Vol. 32, pages 100-105, 1967 and in its Measurement of Appearance, Wiley &amp; Sons, New York, 1975. A coated glass product having a Hunter value of 12 or less is considered not to exhibit appreciable observable color. Listed in Table 3 under the column titled Color Saturation Index is the Hunter value measurement for the examples. As you can see, all samples have a color saturation index below 12.

TABLE 3

<td></td><td>CMBE</td><td>CMBE</td><td>CMBE</td><td>TEOS</td><td>TEOS</td><td>TEOS</td>

<td>Sample</td><td>Unit 61</td><td>Unit 62</td><td>Unit 64</td><td>Unit 61</td><td>Unit 62</td><td>Cell 64</td>

<td> 4</td><td>molar%</td><td>molar%</td><td>molar%</td><td>molar%</td><td>molar%</td><td>molar%</td>

<td> 1</td><td> 0,280</td><td> 0,190</td><td> 0,490</td><td> 0,050</td><td> 0,050</td><td> 0,020</td>

<td> 2</td><td> 0,290</td><td> 0,300</td><td> 0,600</td><td> 0,100</td><td> 0,160</td><td> 0,300</td>

<td> 3</td><td> 0,350</td><td> 0,200</td><td> 0,940</td><td> 0,300</td><td> 0,300</td><td> 0,270</td>

<td> 4</td><td> 0,400</td><td> 0,200</td><td> 0,940</td><td> 0,300</td><td> 0,300</td><td> 0,330</td>

<td> 5</td><td> 0,600</td><td> 0,758</td><td> 0,790</td><td> 0,390</td><td> 0,400</td><td> 0,350</td>

<td>δ</td><td> 0,500</td><td> 0,600</td><td> 1,200</td><td> 0,265</td><td> 0,300</td><td> 0,100</td>

Mod. 71 · 20,000 ex. 92/12

CMBE stands for monobutyl tin chloride.

TEOS means tetraethoxysilane

<td></td><td>TEF</td><td>TEF</td><td>TEF</td><td>WATER</td><td>WATER</td><td>WATER</td>

<td>Sample</td><td>Unit 61</td><td>Unit 62</td><td>Unit 64</td><td>Unit 61</td><td>Unit 62</td><td>Unit 64</td>

<td> #</td><td>molar%</td><td>molar%</td><td>molar%</td><td>molar%</td><td>molar%</td><td>molar%</td>

<td> 1</td><td> 0,300</td><td> 0,100</td><td> 0,025</td><td> 0,170</td><td> 0,600</td><td> 0,600</td>

<td> 2</td><td> 0,280</td><td> 0,110</td><td> 0,039</td><td> 0,180</td><td> 0,330</td><td> 0,630</td>

<td> 3</td><td> 0,280</td><td> 0,120</td><td> 0,070</td><td> 0,150</td><td> 0,610</td><td> 0,370</td>

<td> 4</td><td> 0,280</td><td> 0,100</td><td> 0,050</td><td> 0,150</td><td> 0,610</td><td> 0,370</td>

<td> 5</td><td> 0,266</td><td> 0,120</td><td> 0,066</td><td> 0,150</td><td> 0,180</td><td> 0,640</td>

<td> 6</td><td> 0,400</td><td> 0,300</td><td> 0,288</td><td> 0,400</td><td> 1.000</td><td> 1,000</td>

TEF means triethylphosphite

<td>TEMPERATURE</td><td>VELOCITY</td><td>INDEX</td><td>GRADIENT</td><td>THICKNESS</td>

<td>GLASS Sample</td><td>GLASS</td><td>SATURATION</td><td>OF THICKNESS</td><td>Oxide</td>

<td></td><td></td><td>BY HEART</td><td></td><td>TIN</td>

<td># (° F) ° C</td><td>(in / min)</td><td></td><td>THE</td><td>THE</td>

<td></td><td>m / s</td><td></td><td>m</td><td>m</td>

<td> 1</td><td> 666</td><td> (1230)</td><td> 0,144</td><td> (340)</td><td> 5, 0</td><td>1.20x110 · '</td><td> (1200)</td><td>4.00x10 · '</td><td> (4000)</td>

<td> 2</td><td> 668</td><td> (1234)</td><td> 0,144</td><td> (340)</td><td> 5,0</td><td>1.10x10 ''</td><td> (1100)</td><td>4.00x10 ''</td><td> (4000)</td>

<td> 3</td><td> 64$</td><td> (1194)</td><td> 0,144</td><td> (340)</td><td> 2,3</td><td>1.25x10 · '</td><td> (1250)</td><td>3.70X10 · '</td><td> (3700)</td>

<td> 4</td><td> 649</td><td> (1200)</td><td> 0, 144</td><td> (340)</td><td> 3,6</td><td>1.15x10 ''</td><td> (1150)</td><td>3.65x10 ''</td><td> (3650)</td>

<td> 5</td><td> 643</td><td> (1190)</td><td> 0,208</td><td> (490)</td><td> 8,9</td><td>8.50x10 '·</td><td> (850)</td><td>1.75x10 ''</td><td> (1750)</td>

<td> 6</td><td> 649</td><td> (1200)</td><td> 0,296</td><td> (700)</td><td> 4,6</td><td>1.00x10 ''</td><td> (1000)</td><td>1.70x10 ''</td><td> (1700)</td>

Mod. 71 · 20,000 ex. - 08/20

While some embodiments of the present invention have been described and illustrated, it will be apparent to those skilled in the art that various changes and other modifications may be made without departing from the scope of the appended claims.

Lisbon, 10 MAL'934

By PPG

<img file="PT101462B_D0003.tif" />

by Fropriccede Induslriel TUf / orlo-Arçe and 'Concilação, 3, HWffP