BR112019016246A2 - thermally insulating glass laminates with a non-uniform coating layer and a plurality of sealed gas molecule cavities - Google Patents

Abstract

the present disclosure provides thermally insulating glass laminates that mitigate or prevent heat loss from heated cavities. the present disclosure also provides a heating device, such as an oven, which includes insulating glass laminates as diffusers, to protect a functional element. in some embodiments, thermally insulating glass laminates have a first substrate, a second substrate and a non-uniform, non-conductive or low conductivity coating layer that forms a chemical bond with at least one internal surface of the substrates. the coating layer can be about 0.010 inches (0.254 mm) thick or less and forms a pattern that contacts about 30% or less of at least one internal surface of a substrate. the coating layer also forms a plurality of sealed cavities of gas molecules between the substrates. since there is a small amount of gas molecules in each cavity, the transfer of heat by convection between the substrates is minimized, thus minimizing the loss of heat through the laminates to the surrounding environment.

Description

THERMALLY INSULATING GLASS LAMINATES WITH A NON-UNIFORM COATING LAYER AND A PLASTER OF SEALED CAVITIES OF GAS MOLECULES

BACKGROUND OF THE REVELATION

1. Field of Revelation [0001] The present revelation refers to thermally insulating glass laminates.

2. Description of the related technique [0002] Glass laminates are used in high temperature applications, such as windows and site glass in order to visualize a heated cavity. To minimize heat loss from the cavity, laminates have multiple glass panels with a gap between the panels to prevent direct heat transfer from the cavity to the outer panel, but the temperature of the outer panel still increases and the heat escapes to the surrounding environment because of the convective heat transfer through the air in the gap between the panels. Heat insulating coatings have been used to prevent heat loss, but many coatings are inadequate.

[0003] A light diffuser is an element that transmits visible light, but minimizes the transmission of medium and long wavelength infrared light. Most light diffusers are not necessarily suitable for thermally insulating functional components such as LEDs, cameras, lighting sets, wiring, sensors and semiconductor components from high temperatures in residential and commercial ovens and other heated cavities. This is particularly problematic for functional components, such as LEDs, which are not designed for

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2/13 withstand high temperatures. One approach to isolating a lighting assembly from the high temperatures in the furnaces is to provide an air gap that cools the lighting assembly by convection. Another approach is to use a heat sink. Yet another approach is to protect the lighting set with a lens coated with a low-e (low emissivity) coating. However, such approaches do not necessarily adequately isolate the functional elements from high temperatures.

REVELATION SUMMARY [0004] The present disclosure describes thermally insulating glass laminates that mitigate or prevent heat loss from heated cavities. In some embodiments, thermally insulating glass laminates comprise a non-uniform, non-conductive or low conductivity coating layer that forms a chemical bond with at least one internal surface of the substrates, where the coating layer can have a thickness of about 0.010 inches (0.254 mm) or less. In some embodiments, the non-uniform, non-conductive or low conductivity coating layer helps to form a plurality of three-dimensional cavities sealed between the substrates, each having a very small volume with a small amount of gas molecules in it. Since there is a small amount of gas molecules in each cavity, the transfer of heat by convection between the substrates is minimized, thus minimizing heat loss through the laminates and to the surrounding environment.

[0005] Current literature suggests that thermally insulating glass laminates are optimal insulators when

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3/13 gas cavity has a thickness of about 15 millimeters, where thinner cavities have greater conduction losses and thicker cavities have greater convection losses. This knowledge suggests that decreasing the thickness of the cavity would increase conduction losses, but conduction losses are not increased in the present disclosure.

[0006] The thermally insulating glass laminates of the development can be used, in a non-limiting example, in high temperature applications, such as local windows and glass in residential and industrial ovens and applications with heated cavities where low heat loss is desired and cold exit window temperatures. In some embodiments, high temperature applications are above about 175 ° C.

[0007] In one embodiment, the present disclosure provides a thermally insulating laminate comprising a first glass substrate having an internal surface, a second glass substrate having an internal surface and a non-uniform, non-conductive or low conductivity coating layer which forms a chemical bond with at least one internal surface. The coating layer has a thickness of about 0.010 inches (0.254 mm) or less and forms a pattern that contacts about 30% or less of at least one internal surface. A plurality of sealed cavities of gas molecules exist between the substrates.

[0008] The present disclosure also refers to light diffusers that thermally insulate functional components, such as LEDs, cameras, sets of

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4/13 lighting, wiring, sensors and semiconductor components, inside or near heated cavities. In some embodiments, the light diffuser comprises the thermally insulating glass laminate described herein. The light diffuser may have a thermally insulating glass laminate located between the oven cavity and the functional element so that the laminate partially or completely isolates the functional element from the temperature within the cavity. In some embodiments, a heat reflective coating is provided on one or more components of the laminate to provide additional thermal insulation. BRIEF DESCRIPTION OF THE DRAWINGS [0009] Figure 1 illustrates a portion of a laminate with a plurality of circular shaped cavities formed using a non-uniform coating layer which contacts about 30% or less of at least one internal surface of the substrates.

[00010] Figure 2 shows a schematic diagram of the laminate of the present disclosure.

[00011] Figure 3 shows a schematic diagram of an oven using the laminate of the present disclosure to protect a functional component.

DETAILED DESCRIPTION OF THE REVELATION [00012] The present disclosure provides thermally insulating glass laminates that mitigate or prevent heat loss from heated cavities. In some embodiments, thermally insulating glass laminates comprise a first glass substrate having an internal surface, a second glass substrate having an internal surface and a non-uniform, non-conductive or coating layer

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5/13 low conductivity that forms a chemical bond with at least one internal surface, where the non-conductive, non-conductive or low conductivity coating layer has a thickness of about 0.010 inches (0.254 mm) or less and forms a pattern that contacts about 30% of less than at least one internal surface and in which a plurality of sealed cavities of gas molecules exist between the substrates.

[00013] The plurality of sealed cavities of gas molecules may comprise in some embodiments without limitation about 5 to about 400, about 100 to about 400, or about 5 to about 50 cavities per square centimeter of the gas layer. coating. The width of the coating measured between each well can be without limitation less than about 0.5, about 0.01 to about 0.5, or about 0.02 to about 0.1 millimeters. The coating layer must prevent the substrates from touching each other. One of the objectives of the coating layer is to provide the spacing between the substrates to retain gas molecules in the plurality of sealed cavities between the substrates.

[00014] In some embodiments, the conductivity of the coating layer is about 5 W / (m-K) or less, or about 3.5 W / (m-K) or less. In some embodiments, the conductivity of the coating layer is less than the conductivity of the substrates that come into contact with the coating composition. For the purposes of the present disclosure, a low conductivity coating layer has a conductivity of about 5 W / (m-K) or less and a non-conductive coating layer has a conductivity of 0 or about 0 W / (m-K).

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6/13 [00015] The coating layer creates an insulating layer between the substrates to minimize convection currents and reduce heat transfer between the substrates. In some embodiments, the coating layer is a non-conductive or low conductivity coating layer formed from a coating composition, such as, in a non-limiting example, an enamel, a frit or a combination thereof, comprising each a ceramic compound, a glass compound or a combination thereof, optionally with other compounds, some of which may evaporate when the coating composition is cured to form the coating layer. In certain embodiments, the ceramic and glass compounds in the coating layer have a similar composition and thermal expansion properties compared to the substrate that contacts the coating layer.

[00016] Figures 1 and 2 show schematic drawings of laminate 10 of the present disclosure. Laminate 10 has first glass substrate 20, second glass substrate 30 and coating 40. Coating 40 has pores 45, which, as discussed above, form cavities between substrates 20 and 30 in laminate 10.

[00017] The coating composition may comprise a frit, which is a mixture of inorganic chemical substances produced by the rapid extinction of a complex combination of molten materials and confinement of the chemical substances thus manufactured as non-migratory components of flakes or solid granules. Chips include in a non-limiting example all chemical substances specified below when they are

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7/13 intentionally manufactured in frit production. Primary members include, without limitation, oxides of some or all of the elements listed below, where fluorides from these elements may also be included: aluminum, antimony, arsenic, barium, bismuth, boron, cadmium, calcium, cerium, chromium, cobalt, copper, gold, iron, lanthanum, lead, lithium, magnesium, manganese, molybdenum, neodymium, nickel, niobium, phosphorus, potassium, silicon, silver, sodium, strontium, tin, titanium, tungsten, vanadium, zinc, zirconium and combinations of themselves. The most common fries are bismuth and zinc fries. Frits can comprise pigments added in small percentages for color purposes.

[00018] A non-limiting example of a suitable coating composition is:

Crystalline Silica: 11 to 15%

Borates: 19 to 22%

Zinc Oxide: 25 to 29%

Titanium dioxide: 32 to 36%

Manganese Compound: 0 to 2%

Iron Oxide: 0 to 2%

Chromium Compound: 0 to 2%

Cobalt Compound: 0 to 3%

Alumina: 3 to 6% [00019] Another non-limiting example of a suitable coating composition is:

Crystalline Silica: 34 to 38%

Borates: 8 to 12%

Zinc oxide: 16 to 20%

Titanium dioxide: 5 to 9%

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8/13

Manganese Compound: 0 to 3%

Iron Oxide: 0 to 3%

Chromium Compound: 11 to 15%

Copper compound: 8 to 12% [00020] The non-uniform coating layer can be applied to the substrate by screen printing or any other suitable technique. As shown in Figure 1, the non-uniform coating layer has voids and does not contact the entire surface of the substrate. The non-uniform coating layer can form a regular or irregular pattern. In screen printing, for example, the coating composition is injected through the canvas to form the pattern. The standardized, non-uniform coating composition helps to form a plurality of sealed cavities of gas molecules between the substrates. The coating layer can be transparent or colored. Intermediate layers, additional substrates and additional coating layers can be present as desired.

[00021] Laminates can be formed by chemically bonding the coating layer to at least one of the substrates in any way known to those skilled in the art. For a non-limiting example, laminates can be formed in stages comprising applying the coating composition to a first substrate, heating the coating composition to adhere the coating composition to the first substrate, applying a second substrate to the heated coating composition and burning the coating composition heated to form a chemical bond between the coating layer and at least one of the substrates. In other modalities, laminates are

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Formed by steps comprising applying the coating composition to a first substrate, applying a second substrate to the coating composition, then burning the coating composition to form a chemical bond between the coating layer and at least one of the substrates . In all embodiments, at least one of the coating layers, the first substrate and the second substrate can form a chemical bond with at least one of the others.

[00022] The coating layers of the developer, at least the coating layer that touches the substrate, are pyrolytic because the coating layer is chemically bonded to the substrate by sharing an oxygen atom and becoming part of the Si-OX chain . Pyrolytic coatings are hard coatings and differ from soft coatings, such as paint that is mechanically adhered to a substrate. Pyrolytic coatings, compared to bonded coatings, have superior wear resistance, are not easily removable and do not normally require protective coatings. The pyrolytic coatings of the development can be applied in any manner known to those skilled in the art, such as by deposition using a high temperature plasma or screen printing process.

[00023] The term glass as used herein includes glass and ceramic glass, including, but not limited to, soda lime, borosilicate, lithium aluminum silicate and combinations thereof. The term substrate means a platform on which the coatings described here and other elements can be applied. The substrates are not

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10/13 limited in form. The substrates can be flat, curved, concave or convex, and can have rectangular, square or other dimensions. In some embodiments, the substrate comprises a glass material and is about 1 to about 10 mm thick or about 2 to about 5 mm thick.

[00024] The coating layer is non-uniform because it does not cover the entire surface area of a substrate. Instead, the non-uniform coating layer is distributed in a pattern that helps to form a plurality of sealed cavities of gas molecules between the substrates. The pattern may comprise many coating segments connected in a grid-like manner to encompass the plurality of cavities. The cavities are essentially empty that the gas molecules can occupy without substantial movement. The shape of the cavities is not critical. The cavities can be in the form of honeycombs, circles or any other shapes that produce a plurality of three-dimensional gas-filled voids between the two substrates and coating segments between the voids. Figure 1 illustrates a portion of a laminate that has a plurality of circular shaped cavities and a non-uniform, standardized coating layer that contacts about 30% or less of at least one internal surface of the substrates.

[00025] In some embodiments, the coating layer has a thickness of about 0.010 inches (0.254 mm) or less, about 0.005 inches (0.127 mm) or less, or about 0.001 inches (0.0254 mm) or less . It is desirable to form a coating layer with such a small thickness and use a coating composition

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11/13 non-conductive or low conductivity to minimize conductive heat transfer. In some embodiments, the non-uniform coating layer is distributed over most substrates and forms a pattern that comes in contact with about 30% or less of at least one internal surface of the substrates, about 20% or less of at least one internal surface of the substrates, or about 10% or less of at least one internal surface of the substrates (in other words, the cavities / voids contact about 70% or more, about 80% or more, or about 90% or more than at least one internal surface of the substrates). The non-uniform coating layer with these small thicknesses helps to produce a plurality of sealed three-dimensional cavities, each having a very small volume with a small amount of gas molecules inside. Since there is a small amount of gas molecules in each cavity, the heat transfer by convection between the substrates is minimized, thus minimizing the heat loss through the laminates to the surrounding environment. The cavities act essentially as thermal insulators. The gas can be air or inert gas. In some embodiments, there is a partial or total vacuum in the cavities. In other modalities, there is no vacuum.

[00026] The present disclosure also refers to light diffusers that thermally insulate functional components, such as LEDs, cameras, lighting sets, wiring, sensors and semiconductor components, inside or near heated cavities. In some embodiments, the light diffuser comprises a laminate of

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12/13 thermally insulating glass described here. The light diffuser may have a thermally insulating glass laminate located between the oven cavity and the functional element so that the laminate partially or completely isolates the functional element from the temperature within the cavity. In some embodiments, a heat reflective coating is provided on one or more components of the laminate to provide additional thermal insulation.

[00027] Unlike lenses with or without low-e (low emission) coatings, the thermally insulating laminates disclosed here are visibly transparent, similar to a window or local glass, since they do not significantly distort the image of the element by behind the laminate. As a result, laminates can be used as light diffusers to thermally insulate functional elements in or near an oven, for example, while also providing sufficient transmission of visible light to allow a camera or other functional element to view the cavity contents through of the laminate.

[00028] Light diffusers and functional elements can be located anywhere inside the heated cavity, such as at the rear, side or top, for example. In some embodiments, the light diffuser is parallel to one of the six sides of the oven cavity, such as within the perimeter of that side, in a manner similar to an oven window on the front door of an oven, so that the diffuser of light is located between the center of the oven cavity and the functional element.

[00029] In Figure 3, a diagram of an oven interior

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13/13

100 comprising laminate 10, which protects functional component 50. In the embodiment shown, laminate 10 is parallel and adjacent to one side of the interior 100, and protects component 50 from heat. As discussed earlier, other locations for laminate 10 and component 50 are contemplated by the present disclosure.

[00030] Although this description has been described with reference to one or more particular modalities, it will be understood by those skilled in the art that various changes can be made and the equivalents can be replaced by elements of the same without departing from its scope. In addition, many modifications can be made to adapt a particular situation or material to the teachings of the revelation without departing from its scope. Therefore, it is intended that the disclosure is not limited to the particular modality (s) revealed as the best modality contemplated for the realization of this disclosure. The intervals revealed here include all sub-intervals between them.

Claims (3)

1. Thermally insulating laminate characterized by the fact that it comprises: a first glass substrate having an internal surface; a second glass substrate having an internal surface; and a non-uniform, non-conductive or low-conductivity coating layer that forms a chemical bond with at least one internal surface, and where the coating layer has a thickness of about 0.010 inches (0.254 mm) or less and forms a pattern that contacts about 30% or less of at least one internal surface, and in which a plurality of sealed cavities of gas molecules are between the first and the second substrates. 2. Laminate according to claim 1, characterized by the fact that the plurality of sealed cavities of gas molecules comprises about 5 to about 400 cavities per square centimeter of layer in coating. 3. Laminate, in wake up with claim 1, characterized by fact that a layer width in coating measured between each of the plurality in sealed cavities it's about from 0.01 to about 0.5 mm. 4. Laminate, in wake up with claim 1, characterized by fact that the layer thickness in coating is fence 0.005 inches (0.127 mm) or Petition 870190075635, of 08/06/2019, p. 36/42 2/3 less. 5. Laminate according to claim 1, characterized in that the thickness of the coating layer is about 0.001 inches (0.0254 mm) or less. 6. Laminate formation method, as defined in claim 1, characterized by the fact that it comprises the steps of applying a coating composition to the first substrate, heating the coating composition to adhere the coating composition to the first substrate, applying the second substrate to the heated coating composition and burning the heated coating composition to form the chemical bond. 7. Laminate forming method, as defined in claim 1, characterized in that it comprises the steps of applying a coating composition to the first substrate, applying the second substrate to the coating composition and burning the coating composition to form the chemical bond . 8. Laminate according to claim 1, characterized in that the coating layer is an enamel or frit comprising a ceramic compound, a glass compound, or a combination thereof. 9. Laminate, in wake up with the claim 1, characterized by fact that the layer coating is transparent. 10. Laminate, in wake up with the claim 1, characterized by fact that the coating layer has conductivity lower than the conductivity of the first and Petition 870190075635, of 08/06/2019, p. 37/42 3/3 according to substrates. 11. Laminate, according to claim 1, characterized by the fact that there is no vacuum in the cavities. 12. Oven characterized by the fact that it comprises laminate, as defined in claim 1, in which the oven operates at a temperature above about 175 ° C. 13. Oven according to claim 12, characterized by the fact that a window or a glass area of the oven comprises the laminate. 14. Oven characterized by the fact that it comprises: a light diffuser; a functional element inside or near the oven, in which the light diffuser thermally isolates the functional element, transmits visible light and minimizes the transmission of long and medium wavelength infrared light; and wherein the light diffuser comprises the laminate, as defined in claim 1. 15. Oven according to claim 14, characterized by the fact that the functional element is an LED, a camera, a lighting set, wiring, a sensor, a semiconductor component or a combination thereof.