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US-12623959-B2 - Solar control coating with high solar heat gain coefficient

US12623959B2US 12623959 B2US12623959 B2US 12623959B2US-12623959-B2

Abstract

A coating provides a high solar heat gain coefficient (SHGC) and a low overall heat transfer coefficient (U-value) to trap and retain solar heat. The coating and coated article are particularly useful for use in architectural transparencies in northern climates. The coating includes a first dielectric layer; a continuous metallic layer formed over at least a portion of the first dielectric layer, the metallic layer having a thickness less than 8 nm; a primer layer formed over at least a portion of the metallic layer; a second dielectric layer formed over at least a portion of the primer layer; and an overcoat formed over at least a portion of the second dielectric layer. When used on a No. 3 surface of a reference IGU, the coating provides a SHGC of greater than or equal to 0.6 and a U-value of less than or equal to 0.35.

Inventors

  • Andrew V. Wagner

Assignees

  • VITRO FLAT GLASS LLC

Dates

Publication Date
20260512
Application Date
20230613

Claims (19)

  1. 1 . A coated transparency, comprising: a. a first substrate having a No. 1 surface and a No. 2 surface; b. a second substrate spaced from the first substrate, with a gas-filled gap between the first substrate and the second substrate, the second substrate having a No. 3 surface and a No. 4 surface, with the No. 3 surface facing the No. 2 surface; and c. a coating formed over at least a portion of the No. 3 surface and defining a side of the gas-filled gap opposite the No. 2 surface, the coating comprising: i. a first dielectric layer formed over at least a portion of the No. 3 surface; ii. a continuous metallic layer formed over at least a portion of the first dielectric layer, the metallic layer having a thickness less than 8 nm; iii. a primer layer formed over at least a portion of the metallic layer; iv. a second dielectric layer formed over at least a portion of the primer layer; and v. an overcoat formed over at least a portion of the second dielectric layer, wherein the coated transparency has a solar heat gain coefficient greater than or equal to 0.6 and a heat transfer coefficient less than or equal to 0.35, wherein the gas-gap is filled with air or a non-reactive gas, and wherein the first dielectric layer comprises a first film and a second film, the second film in direct contact over at least a portion of the first film.
  2. 2 . The coated transparency of claim 1 , wherein the first film comprises zinc alloy oxide and wherein the second film comprises metal oxide; and wherein the first dielectric layer has a thickness in the range of 40 nm to 50 nm.
  3. 3 . The coated transparency of claim 1 , wherein the first film has a thickness in the range of 35 nm to 45 nm.
  4. 4 . The coated transparency of claim 1 , wherein the second film has a thickness in the range of 3 nm to 15 nm.
  5. 5 . The coated transparency of claim 1 , wherein the first film comprises zinc stannate and the second film comprises zinc oxide.
  6. 6 . The coated transparency of claim 1 , wherein the metallic layer comprises silver having a thickness less than or equal to 7.5 nm.
  7. 7 . The coated transparency of claim 1 , wherein the overcoat comprises titania and has a thickness in the range of less than or equal to 6 nm.
  8. 8 . The coated transparency of claim 1 , wherein the second dielectric layer comprises a first film and a second film, the second film in direct contact over at least a portion of the first film.
  9. 9 . The coated transparency of claim 8 , wherein the second dielectric layer has a thickness in the range of 30 nm to 40 nm.
  10. 10 . The coated transparency of claim 8 , the first film has a thickness in the range of 5 nm to 9 nm, and the second film has a thickness in the range of 26 nm to 32 nm.
  11. 11 . The coated transparency of claim 1 , wherein the second dielectric layer comprises a first film comprising zinc oxide and a second film comprising zinc stannate.
  12. 12 . The coated transparency of claim 1 , wherein the overcoat has a thickness in the range of 1-10 nm and the overcoat comprises titania.
  13. 13 . The coated transparency of claim 1 , wherein the second substrate is a glass substrate, wherein the first dielectric layer has a thickness in the range of 40 nm to 50 nm, the second film has a thickness in the range of 3 nm to 15 nm, and the first film has a thickness in the range of 25 nm to 40 nm, wherein the metallic layer comprises silver having a thickness less than or equal to 7.5 nm, wherein the primer film comprises titanium, wherein the second dielectric layer comprises a zinc oxide film and a zinc stannate film deposited over the zinc oxide film, the second dielectric layer has a thickness in the range of 30 nm to 40 nm, and the zinc oxide film has a thickness in the range of 3 nm to 15 nm, wherein the overcoat has a thickness in the range of 2 nm to 6 nm and the overcoat comprises titania, and wherein the solar heat gain coefficient is greater than or equal to 0.65 and the heat transfer coefficient is less than or equal to 0.33.
  14. 14 . The coated transparency of claim 1 , wherein the second substrate is a glass substrate, wherein the first film comprises zinc stannate, and the second film comprises zinc oxide, wherein the first dielectric layer has a thickness in the range of 41 nm to 48 nm, the first film has a thickness in the range of 35 nm to 40 nm, and the second film has a thickness in the range of 6 nm to 8 nm, wherein the metallic layer comprises silver having a thickness less than or equal to 7 nm, wherein the primer film comprises titanium, wherein the second dielectric layer comprises a first film comprising zinc oxide, a second film comprising zinc stannate, wherein the second dielectric layer has a thickness in the range of 28 nm to 40 nm, the first film has a thickness in the range of 3 nm to 5 nm, and the second film has a thickness in the range of 25 nm to 35 nm, wherein the overcoat has a thickness in the range of 4 nm to 10 nm and the overcoat comprises titania, and wherein the solar heat gain coefficient is greater than or equal to 0.65 and the heat transfer coefficient is less than or equal to 0.35.
  15. 15 . A coated transparency, comprising: a. a first substrate having a No. 1 surface and a No. 2 surface; b. a second substrate spaced from the first substrate, with a gas-filled gap between the first substrate and the second substrate, the second substrate having a No. 3 surface and a No. 4 surface, with the No. 3 surface facing the No. 2 surface; and c. a coating formed over at least a portion of the No. 3 surface and defining a side of the gas-filled gap opposite the No. 2 surface, the coating comprising: i. a first dielectric layer formed over at least a portion of the No. 3 surface; ii. a continuous metallic layer formed over at least a portion of the first dielectric layer, the metallic layer having a thickness less than 8 nm; iii. a primer layer formed over at least a portion of the metallic layer; iv. a second dielectric layer formed over at least a portion of the primer layer; and v. an overcoat formed over at least a portion of the second dielectric layer, wherein the coated transparency has a solar heat gain coefficient greater than or equal to 0.6 and a heat transfer coefficient less than or equal to 0.35, wherein the gas-gap is filled with air or a non-reactive gas, wherein the first dielectric layer comprises a first film and a second film, and wherein the first film comprises zinc stannate and the second film comprises zinc oxide.
  16. 16 . A coated transparency, comprising: a. a first substrate having a No. 1 surface and a No. 2 surface; b. a second substrate spaced from the first substrate, with a gas-filled gap between the first substrate and the second substrate, the second substrate having a No. 3 surface and a No. 4 surface, with the No. 3 surface facing the No. 2 surface; and c. a coating formed over at least a portion of the No. 3 surface and defining a side of the gas-filled gap opposite the No. 2 surface, the coating comprising: i. a first dielectric layer formed over at least a portion of the No. 3 surface; ii. a continuous metallic layer formed over at least a portion of the first dielectric layer, the metallic layer having a thickness less than 8 nm; iii. a primer layer formed over at least a portion of the metallic layer; iv. a second dielectric layer formed over at least a portion of the primer layer; and v. an overcoat formed over at least a portion of the second dielectric layer, wherein the coated transparency has a solar heat gain coefficient greater than or equal to 0.6 and a heat transfer coefficient less than or equal to 0.35, wherein the gas-gap is filled with air or a non-reactive gas, and wherein the second dielectric layer comprises a first film and a second film, the second film in direct contact over at least a portion of the first film.
  17. 17 . A coated transparency, comprising: a. a first substrate having a No. 1 surface and a No. 2 surface; b. a second substrate spaced from the first substrate, with a gas-filled gap between the first substrate and the second substrate, the second substrate having a No. 3 surface and a No. 4 surface, with the No. 3 surface facing the No. 2 surface; and c. a coating formed over at least a portion of the No. 3 surface and defining a side of the gas-filled gap opposite the No. 2 surface, the coating comprising: i. a first dielectric layer formed over at least a portion of the No. 3 surface; ii. a continuous metallic layer formed over at least a portion of the first dielectric layer, the metallic layer having a thickness less than 8 nm; iii. a primer layer formed over at least a portion of the metallic layer; iv. a second dielectric layer formed over at least a portion of the primer layer; and v. an overcoat formed over at least a portion of the second dielectric layer, wherein the coated transparency has a solar heat gain coefficient greater than or equal to 0.6 and a heat transfer coefficient less than or equal to 0.35, wherein the gas-gap is filled with air or a non-reactive gas, and wherein the second dielectric layer comprises a first film comprising zinc oxide and a second film comprising zinc stannate.
  18. 18 . A coated transparency, comprising: a. a first substrate having a No. 1 surface and a No. 2 surface; b. a second substrate spaced from the first substrate, with a gas-filled gap between the first substrate and the second substrate, the second substrate having a No. 3 surface and a No. 4 surface, with the No. 3 surface facing the No. 2 surface; and c. a coating formed over at least a portion of the No. 3 surface and defining a side of the gas-filled gap opposite the No. 2 surface, the coating comprising: i. a first dielectric layer formed over at least a portion of the No. 3 surface; ii. a continuous metallic layer formed over at least a portion of the first dielectric layer, the metallic layer having a thickness less than 8 nm; iii. a primer layer formed over at least a portion of the metallic layer; iv. a second dielectric layer formed over at least a portion of the primer layer; and v. an overcoat formed over at least a portion of the second dielectric layer, wherein the coated transparency has a solar heat gain coefficient greater than or equal to 0.6 and a heat transfer coefficient less than or equal to 0.35, wherein the gas-gap is filled with air or a non-reactive gas, wherein the second substrate is a glass substrate, wherein the first dielectric layer comprises a first film and a second film, wherein the first dielectric layer has a thickness in the range of 40 nm to 50 nm, the second film has a thickness in the range of 3 nm to 15 nm, and the first film has a thickness in the range of 25 nm to 40 nm, wherein the metallic layer comprises silver having a thickness less than or equal to 7.5 nm, wherein the primer film comprises titanium, wherein the second dielectric layer comprises a zinc oxide film and a zinc stannate film deposited over the zinc oxide film, the second dielectric layer has a thickness in the range of 30 nm to 40 nm, and the zinc oxide film has a thickness in the range of 3 nm to 15 nm, wherein the overcoat has a thickness in the range of 2 nm to 6 nm and the overcoat comprises titania, and wherein the solar heat gain coefficient is greater than or equal to 0.65 and the heat transfer coefficient is less than or equal to 0.33.
  19. 19 . A coated transparency, comprising: a. a first substrate having a No. 1 surface and a No. 2 surface; b. a second substrate spaced from the first substrate, with a gas-filled gap between the first substrate and the second substrate, the second substrate having a No. 3 surface and a No. 4 surface, with the No. 3 surface facing the No. 2 surface; and c. a coating formed over at least a portion of the No. 3 surface and defining a side of the gas-filled gap opposite the No. 2 surface, the coating comprising: i. a first dielectric layer formed over at least a portion of the No. 3 surface; ii. a continuous metallic layer formed over at least a portion of the first dielectric layer, the metallic layer having a thickness less than 8 nm; iii. a primer layer formed over at least a portion of the metallic layer; iv. a second dielectric layer formed over at least a portion of the primer layer; and v. an overcoat formed over at least a portion of the second dielectric layer, wherein the coated transparency has a solar heat gain coefficient greater than or equal to 0.6 and a heat transfer coefficient less than or equal to 0.35, wherein the gas-gap is filled with air or a non-reactive gas, wherein the second substrate is a glass substrate, wherein the first dielectric layer comprises a first film and a second film, wherein the first film comprises zinc stannate, and the second film comprises zinc oxide, wherein the first dielectric layer has a thickness in the range of 41 nm to 48 nm, the first film has a thickness in the range of 35 nm to 40 nm, and the second film has a thickness in the range of 6 nm to 8 nm, wherein the metallic layer comprises silver having a thickness less than or equal to 7 nm, wherein the primer film comprises titanium, wherein the second dielectric layer comprises a first film comprising zinc oxide, a second film comprising zinc stannate, wherein the second dielectric layer has a thickness in the range of 28 nm to 40 nm, the first film has a thickness in the range of 3 nm to 5 nm, and the second film has a thickness in the range of 25 nm to 35 nm, wherein the overcoat has a thickness in the range of 4 nm to 10 nm and the overcoat comprises titania, and wherein the solar heat gain coefficient is greater than or equal to 0.65 and the heat transfer coefficient is less than or equal to 0.35.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS This application is a continuation of U.S. patent application Ser. No. 17/534,627, filed on Nov. 24, 2021, which is a continuation of Ser. No. 12/774,751, filed on May 6, 2010, now U.S. Pat. No. 11,198,641, issued Dec. 14, 2021, which claims priority to U.S. Patent Application Ser. No. 61/176,534, filed May 8, 2009, the disclosures of which are herein incorporated by reference in their entireties. BACKGROUND OF THE INVENTION Field of the Invention This invention relates generally to solar control coatings and, in one particular embodiment, to a solar control coating providing a high solar heat gain coefficient (SHGC) and a low overall heat transfer coefficient (U-value). Technical Considerations The SHGC is the fraction of incident solar radiation admitted through a window, both directly transmitted, and absorbed and subsequently released inwardly. The lower the SHGC, the less solar heat is transmitted. The U-value is a measure of the rate of non-solar heat loss or gain through a material. The lower the U-value, the greater the resistance to heat flow and the better the insulating value. Solar control coatings are known in the fields of architectural and automotive transparencies. These solar control coatings block or filter selected ranges of electromagnetic radiation, such as in the range of solar infrared or solar ultraviolet radiation, to reduce the amount of solar energy entering the vehicle or building. This reduction of solar energy transmittance helps reduce the load on the cooling units of the vehicle or building, particularly in the summer months. Conventional solar control coatings typically provide a relatively low SHGC. While low SHGC coatings are advantageous in southern climates, they may not be as desirable in northern climates. For northern climates, it may be more energy efficient to have windows with a higher SHGC to trap more heat from the sun inside the building during the winter months. This is particularly true in northern climates where the cooler days of fall and winter weather outnumber the warmer days of spring and summer. Therefore, it would be desirable to provide a coating and/or coated article that improves the energy efficiency of a building in a northern climate where the desire is to trap heat from the sun inside the building. The coating and/or coated article can have a low emissivity to give a low U-value while having a high SHGC so as to let more solar heat into the building and keep it there. SUMMARY OF THE INVENTION A coating provides a high solar heat gain coefficient (SHGC) and a low overall heat transfer coefficient (U-valve) to trap and retain solar heat. The coating and coated article are particularly useful for architectural transparencies in northern climates. A coated transparency comprises a substrate and a coating formed over at least a portion of the substrate. The coating comprises a first dielectric layer formed over at least a portion of the substrate; a continuous metallic layer formed over at least a portion of the first dielectric layer, the metallic layer having a thickness less than 8 nm; a primer layer formed over at least a portion of the metallic layer; a second dielectric layer formed over at least a portion of the primer layer; and an overcoat formed over at least a portion of the second dielectric layer. The coating, when used on the No. 3 surface of a reference IGU, provides a SHGC of greater than or equal to 0.6 and a U-value of less than or equal to 0.35. In one exemplary coating, the first dielectric layer has a thickness in the range of 40 nm to 50 nm. The first dielectric layer comprises a zinc oxide film deposited over a zinc stannate film, the zinc oxide film has a thickness in the range of 3 nm to 15 nm, and the zinc stannate film has a thickness in the range of 25 nm to 40 nm. The metallic layer comprises silver having a thickness less than or equal to 7.5 nm. The primer layer comprises titanium. The second dielectric layer has a thickness in the range of 30 nm to 40 nm. The second dielectric layer comprises a zinc oxide film and a zinc stannate film deposited over the zinc oxide film. The zinc oxide film has a thickness in the range of 3 nm to 15 nm. The overcoat has a thickness in the range of 2 nm to 6 nm and comprises titania. The coating, when used on the No. 3 surface of a reference IGU, provides a SHGC of greater than or equal to 0.6, such as greater than or equal to 0.65 and a U-value of less than or equal to 0.35, such as less than or equal to 0.33. In another exemplary coating, the first dielectric layer comprises a first layer comprising zinc stannate, a second layer comprising zinc oxide, a third layer comprising zinc stannate, and a fourth layer comprising zinc oxide, wherein the first dielectric layer has a thickness in the range of 44 nm to 48 nm, the first layer and third layer each have a thickness in the range of 16 nm to 17 nm, and the second layer and fourth layer each have a