Coated article with removable protective coating and related methods

Coated Articles with Removable Protective Coatings and Related Methods Cross-reference to Related Applications This application is a continuation of part of U.S. Application No. 09/567934 filed on May 10, 2000, which is hereby incorporated by reference .

FIELD OF THE INVENTION The present invention generally relates to removable protective coatings for substrates with and without any functional coating(s), and more specifically to removable protective coatings mainly comprising carbonaceous materials.

BACKGROUND OF THE INVENTION A substrate such as glass, plastic, etc. may have two main surfaces terminating in a peripheral edge, and at least one surface has a visible light transmittance of 0% to less than 100%. Some substrates, such as mirrors, may have one surface that transmits visible light and another surface that reflects visible light. These substrates can be processed into various products and products.

In the glass industry, glass manufacturers prepare large glass plates of, for example, 4 feet (1.2m) X 6 feet (1.8m), and then ship them to processors, who cut these glass plates into various production products. Smaller glass substrates, such as architectural windows, automotive transparent objects, insulating glass (IG) units, mirrors, etc. The glass substrate may or may not include one or more well-known functional coatings, such as solar protection coatings, conductive coatings, anti-reflective coatings, and/or low emissivity coatings. The processor ships the produced products to the user.

Typically, glass manufacturers ship glass sheets to processors in bulk. For example, the glass plates can be bundled and transported in a pallet or some other type of dedicated transport container known in the glass transport field. Generally, during handling, handling, transportation, or storage, the substrate itself and/or the functional coating on the substrate is damaged.

The present invention provides substrates, especially substrates with some visible light transmission properties, such as glass.

200580043882.9 The first new type of removable protective coating. The removable protective coating of the present invention is mainly composed of carbonaceous materials.

SUMMARY OF THE INVENTION In one non-limiting embodiment, the present invention is a coated substrate comprising: a substrate having a surface; and a removable protective coating mainly comprising carbonaceous material deposited on at least part of the substrate.

In another non-limiting embodiment, the present invention is a method for protecting a substrate, the method comprising: depositing a removable protective coating mainly comprising a carbonaceous material on at least a part of the substrate.

DETAILED DESCRIPTION OF THE INVENTION It should be understood that all numerical values used to indicate dimensions, physical properties, component quantities, reaction conditions, etc. in the present and claims are modified by the term "about" in all cases. Therefore, if not pointed to the contrary, the numerical values described below and in the claims may vary according to the desired characteristics attempted to be obtained by the present invention. There is no attempt to limit the application of the principle of equivalence to the scope of the claims in the slightest, and each numerical parameter should be understood at least based on the reported important numbers and by applying common rounding techniques. In addition, it should be understood that all ranges disclosed herein include any and all sub-ranges contained therein. For example, the range should be considered to include any and all sub-ranges (and inclusive of end values) between the minimum value 1 and the maximum value 10; that is, all start with a minimum value of 1 or greater and a maximum value of 10 or less. The sub-range where the value ends, such as 1.0-7.8, 3.0-4.5, 6.3-10.0.

The spatial or directional terms used here, such as "left", "right", "inner", "outer", "above", "below", "top", "bottom", etc. should be understood to include various alternatives Orientation, therefore these terms should not be used for limitation.

As used herein, the terms "on", "apply on/above", "formed on/above", "deposited on/above", "covered" and "provided on/above" "Means formed, deposited or provided on a surface but not necessarily in contact with the surface. For example, "forming" a coating on a substrate does not exclude the presence of phases between the formed coating and the substrate.

200580043882.9 The presence of one or more coatings of the same or different composition. For example, the substrate may include conventional coatings, such as conventional coatings known in the art for coating substrates such as glass or ceramics.

The term "functional coating" as used herein refers to a coating that changes one or more of the physical properties of the substrate (such as optical, thermal, chemical, or mechanical properties) and is not intended to be removed from the substrate during subsequent processing . The functional coating is typically a "durable" or "non-removable" coating, that is, it should be considered that the functional coating is inherent or necessary for the implementation of the end use of the functionally coated substrate. As used herein, when the external surface Or part (that is, the surface or part farthest from the substrate), the inner surface or part (that is, the surface or part closest to the substrate) and the part between the outer surface and the inner surface have substantially the same composition, the coating is "average".

As used herein, when the coating has an increased weight percentage of one or more components and a decreased weight percentage of one or more other components when moving from the inner surface to the outer surface (or vice versa), the coating It is "gradual."

As used herein, when the coating is not uniform, the coating is "non-uniform."

As used herein, the term "low-emissivity coating" describes a functional coating that allows visible wavelength energy (that is, the visible spectrum from 400nm to 780nm) to pass through the coating but reflects longer wavelength infrared energy, And it is generally intended to improve the thermal insulation properties of architectural window glass. Typically, "low emissivity" coatings exhibit an emissivity of at most 0.3, such as at most 0.2.

In a non-limiting embodiment, the present invention is a coated substrate comprising a removable protective coating, that is, the coating is temporary and does not exist on the substrate in its final form. The removable protective coating of the present invention may be provided on at least a part of the substrate or on at least a part of the functional coating formed on the substrate described below.

In a non-limiting embodiment of the present invention, the removable protective coating mainly contains carbonaceous materials. As is well known in the art, carbon can exist in amorphous form and many crystal structures such as diamond and graphite. As used herein, "predominantly" means at least 50% by weight of carbon, such as at least 75% by weight of carbon, or at least 90% by weight of carbon, or at least 95% by weight of carbon, where these weight percentages are based on removable The total weight of the protective coating. In this

200580043882.9 In a non-limiting embodiment of the first invention, the range of the amount of carbon in the material constituting the removable protective coating is at most 100% by weight.

According to the present invention, the removable protective coating can be deposited in any conventional manner, such as but not limited to magnetron sputtering vapor deposition (MSVD), chemical vapor deposition (CVD), spray pyrolysis (ie pyrolysis deposition), atmospheric pressure CVD (APCVD), low pressure CVD (LPCVD), plasma enhanced CVD (PECVD), plasma assisted CVD (PACVD), thermal evaporation or electron beam evaporation, cathodic arc deposition, plasma spray deposition, and wet chemical deposition (such as sol-condensation) Glue, silver mirror treatment, etc.), electron beam, carbon arc deposition, etc.

Examples of suitable CVD coating equipment and methods are disclosed in US Patent Nos. 3,652,246; 4,351,861; 4,719,126; 4,853,257; 5,356,718; and 5,776,236, which are incorporated herein by reference.

Examples of suitable MSVD coating techniques are disclosed in U.S. Patent Nos. 5,028,759; 4,898,789; 4,948,677; 4,834,857; 4,898,790; and 4,806,220, which are incorporated herein by reference.

In a non-limiting embodiment of the invention, the substrate is coated in conventional MSVD coating equipment. The removable protective coating can be deposited by sputtering a carbon-containing sputtering target in a cathode compartment of the coater, such as a graphite target commercially available from MSI (Cohmibiis, OH). The carbon target can be sputtered in any conventional manner to deposit a removable protective coating on the substrate.

In a non-limiting embodiment, the MSVD process can be accomplished by sputtering a carbon target in an atmosphere that is substantially free of oxygen in order to minimize combustion of the sputtered carbon material. "Substantially free of oxygen" means not more than 20 vol% oxygen, for example not more than 10 vol% oxygen, or not containing oxygen. A suitable non-limiting oxygen-free atmosphere contains hydrogen.

Any thickness of removable protective coating can be deposited. For example, it is possible to deposit a removable protective coating with a thickness of up to 50 microns, such as up to 10 microns, or up to 3 microns, or up to 3000 A. or up to 350 A.

According to the present invention, suitable substrates can be made of any material, such as glass, metal, plastics (such as polyacrylate, polycarbonate, and polyethylene terephthalate (PET)), ceramics, or mixtures thereof Or combination.

200580043882.9 In a non-limiting embodiment of the invention, the substrate is glass. The glass can be, for example, conventional soda-lime silica glass, that is, "transparent glass", or it can be colored or other colored glass, borosilicate glass, lead glass, tempered, untempered, annealed or thermally strengthened glass. The glass can be any type of glass, such as conventional float glass or flat glass, and can be any composition with any optical properties, such as any visible light transmission value, ultraviolet transmission value, infrared transmission value, and/or total daylight energy Transmission value. Examples of suitable glass substrates for practicing the present invention are disclosed in US Patent Nos. 4,746,347; 4,792,536; 5,240,886; 5,385,872; and 5,393,593, which are incorporated herein by reference.

The substrate is not limited to any size. For example, the substrate may be larger than about 4 feet (1.2m) x 5 feet (1.5m). The substrate can be any thickness. For example, the thickness of the substrate may range from 1 mm to 50 mm, such as 2 mm to 13 mm or 2 mm to 6 mm. The substrate may have any shape. For example, the substrate can be curved, round, or flat.

It is clear to those skilled in the art that the substrate can be of any type, such as a rigid, flexible, or even self-supporting film or net, as long as the substrate can be coated with the removable protective coating of the present invention. For example, the substrate may be a conventional spandrel used in the commercial glass market.

In a non-limiting embodiment where the substrate is glass and is combined with automobile transparent objects (such as windshields, side lights, tail lights, sunroofs, glass sunroofs, etc.), the removable protective coating of the present invention can be applied to the entire substrate At least a part of the viewable area, for example, at least 50% of the viewable area, or at least 80% of the viewable area, or substantially the entire viewable area.

In another non-limiting embodiment, a removable protective coating can be applied on a substrate for architectural glazing. The removable protective coating can be applied to any part of the substrate.

In a non-limiting embodiment of the present invention, a removable protective coating may be deposited on at least a portion of one or more functional coatings on at least a portion of the substrate. The functional coating may have the same or different composition or function. The functional coating can be uniform or non-uniform. The functional coating can be composed of one or more "films".

In a non-limiting embodiment of the present invention, the functional coating may be a conductive coating, for example

200580043882.9 The first conductive coating as disclosed in US Patent Nos. 5,653,903 and 5,028,759, which are incorporated herein by reference.

In another non-limiting embodiment of the present invention, the functional coating may be an anti-sun coating, such as a coating that reflects or absorbs visible light, infrared or ultraviolet energy. 4,898,789; 5,821,001; 4,716,086; 4,610,771; 4,902,580; 4,716,086; 4,806,220; 4,898,790; 4,834,857; 4,948,677; 5,059,295; For example, these patents are incorporated herein by reference.

In yet another non-limiting embodiment of the present invention, the functional coating may be a low emissivity coating. The low-emissivity coating can be a single layer or a multi-layer coating. The low-emissivity coating may include one or more metals, non-metals, semi-metals, semiconductors, and/or their alloys, compounds, composite materials, combinations or mixtures. Non-limiting examples of low emissivity coatings are disclosed in U.S. Patent Nos. 4,952,423 and 4,504,109 and British document GB 2,302,102, which are incorporated herein by reference.

Non-limiting examples of suitable functional coatings for use in the present invention are the SUNGATE® and SOLARBAN® series coatings available from PPG Industries, Inc. of Pittsburgh, Pennsylvania.

The functional coating(s) can be deposited using any of the conventional techniques described above with respect to the removable protective coating.

In a non-limiting embodiment of the invention, a barrier layer is deposited over the functional coating to prevent the removable protective coating from damaging the functional coating. More specifically, if a barrier layer is not used, the carbon-containing removable protective coating may chemically reduce the upper part of the functional coating, that is, carbon in the protective coating can be removed and oxygen atoms will be extracted from the functional coating. Oxides of carbon. The barrier layer contains materials that can prevent the functional coating from being chemically reduced by the removable protective coating, but do not deleteriously affect the transmission or visual properties of the coated article. In a non-limiting embodiment of the present invention, the barrier layer is selected from oxides, nitrides, and oxynitrides of silicon, titanium, aluminum, aluminum, aluminum, metal, cadmium, and oxynitride, and mixtures thereof.

The barrier layer can be deposited using any of the conventional techniques described above with respect to the removable protective coating. The deposition thickness of the barrier layer can be at most 50 microns, for example at most 25

200580043882.9 micron, or up to 10 microns, or up to 3.0 microns, or up to 1.7 microns, or up to 0.5 microns.

In a non-limiting embodiment of the present invention, the barrier layer includes silicon oxide with a thickness ranging from 25A to 500A, such as 50A.

As described above, the coated substrate of the present invention can be shipped to a processor for further processing. Usually, the processor removes the removable protective coating. The removable protective coating can be removed without damaging the underlying substrate, functional coating(s) or barrier layer (if used).

In a non-limiting embodiment of the invention, the removable protective coating can be removed by burning. For example, when the substrate is a glass plate, the removable protective coating can be removed in a glass tempering kiln, which typically operates at a temperature higher than 1000°F (538C). The burning temperature of the removable protective coating should not be higher than the softening temperature of the substrate. During tempering, the carbonaceous material constituting the removable protective coating is burned and removed from the substrate.

In other non-limiting embodiments of the present invention, the removable protective coating can be removed using a liquid solvent or by wiping, spraying, or immersing the coated substrate in an aqueous or non-aqueous solvent, such as an organic, alkaline or acidic solvent. .

In addition to the coated substrates discussed above, the present invention includes methods of making coated substrates. In a non-limiting embodiment, the present invention is a method for protecting a substrate, the method comprising: depositing a removable protective coating mainly comprising a carbon-containing material on at least a part of the above-mentioned substrate.

The coated substrate according to the present invention, which has a removable protective coating mainly containing a carbonaceous material, proved to have a number of advantages over a coated substrate without the removable protective coating. First, the carbon-containing material can protect the functional coating extremely well, because carbon is chemically inert at room temperature. This results in an improved shelf life of the coated product. Secondly, by reducing the heat energy reflected by the functional coating and acting as a heat absorption layer, the carbon in the protective coating can be removed and the radiant heat transfer to the substrate can be increased. This enables the coated substrate to exhibit improved heat treatment characteristics during tempering, thermal strengthening, bending, etc. For example, the toughening time of the coated substrate according to the present invention may be less than the toughening time required for a coated product that does not contain the removable protective coating of the present invention. Thirdly, the removable temporary coating of the present invention can act as a barrier for certain materials such as oxygen.

200580043882.9 The first barrier layer.

Examples The following non-limiting examples illustrate the present invention. The coated substrate of the present invention is prepared as follows. An Airco ILS-1600 coater with a flat magnetron cathode was used to coat a 1.8 mm thick transparent float glass substrate coated with a Sungate® coating (commercially available from PPG Industries). The substrate is at ambient temperature.

By transferring the substrate to a Si-Al target containing 15% by weight aluminum and 85% by weight silicon, in an atmosphere composed of 80% oxygen and 20% nitrogen, the substrate was deposited at a line speed of 120 inches per minute Barrier layer. The base pressure in the deposition chamber is in the low 10 Torr range and the working pressure is 4 microns. The Si·AI target was operated at a power setting of 2.0 kilowatts, with a voltage of 320 volts and a current of 6.4 amps. After two passes under the target, the transmittance is 70.1%, and the thickness is about 60 angstroms.

Then, a graphite target was deposited by sputtering in a 100% hydrogen atmosphere to apply the removable protective coating of the present invention. The graphite target was operated at a power setting of 4.0 kilowatts, with a voltage of 686 volts and a current of 5.8 amps. After 6 passes under the target, the transmittance was 29.8% and the thickness was measured to be 250 angstroms.

Those skilled in the art can easily understand that the present invention can be modified without departing from the aforementioned disclosed ideas. Therefore, the specific embodiments detailed here are merely illustrative and do not limit the scope of the present invention, and the appendix and any and all equivalents thereof give the scope of the present invention.