Vacuum insulated panel with CTE optimized edge seal
A vacuum insulating panel includes first and second substrates (e.g., glass substrates), a hermetic edge seal, a pump-out port, and spacers sandwiched between at least the two substrates. The gap between the substrates may be at a pressure less than atmospheric pressure to provide insulating properties. The vacuum insulating panel may include a multi-layer edge seal structure with coefficients of thermal expansion (CTEs) of layers of the seal structure optimized for CTE grading.
1. A vacuum insulating panel comprising:
a first glass substrate;
a second glass substrate;
a plurality of spacers provided in a gap between at least the first and second substrates, wherein the gap is at pressure less than atmospheric pressure;
a seal provided at least partially between at least the first and second substrates, the seal comprising a first seal layer, a second seal layer, and a third seal layer, wherein the first seal layer is at least partially located between at least the second and third seal layers;
wherein a coefficient of thermal expansion (CTE) of the second seal layer is greater than a CTE of the first seal layer, a CTE of the third seal layer is greater than the CTE of the first seal layer, the CTE of the second seal layer is less than a CTE of the first glass substrate, and the CTE of the third seal layer is less than a CTE of the second glass substrate; and
wherein the CTE of the first seal layer is from about 7.0 to 7.9×10 −6 mm/(mm*deg. C.), the CTE of the second seal layer is from about 8.0 to 8.8×10 −6 mm/(mm*deg. C.), the CTE of the third seal layer is from about 8.0 to 8.8×10 −6 mm/(mm*deg. C.), the CTE of the first glass substrate is from about 8.7 to 9.3×10 −6 mm/(mm*deg. C.), and the CTE of the second glass substrate is from about 8.7 to 9.3×10 −6 mm/(mm*deg. C.).
2. The vacuum insulating panel of claim 1 , wherein the CTE of the first seal layer is from about 7.2 to 7.9×10 −6 mm/(mm*deg. C.).
3. The vacuum insulating panel of claim 1 , wherein the CTE of the first seal layer is about 7.6×10 −6 mm/(mm*deg. C.).
4. The vacuum insulating panel of claim 1 , wherein CTE of at least one of the second and third seal layers is from about 8.3 to 8.6×10 −6 mm/(mm*deg. C.).
5. The vacuum insulating panel of claim 1 , wherein CTE of at least one of the first and second glass substrates is from about 8.8 to 9.2×10 −6 mm/(mm*deg. C.).
6. The vacuum insulating panel of claim 1 , wherein at least one of the second seal layer and the third seal layer comprises from about 1-20 mol % bismuth oxide and from about 20-65 mol % boron oxide, and comprises at least two times more boron oxide than bismuth oxide in terms of mol %.
7. The vacuum insulating panel of claim 1 , wherein at least one of the second seal layer and the third seal layer comprises from about 30-60 mol % boron oxide.
8. The vacuum insulating panel of claim 7 , wherein the at least one of the second seal layer and the third seal layer comprises from about 1-12 mol % bismuth oxide and from about 0-50 mol % silicon oxide.
9. The vacuum insulating panel of claim 8 , wherein the at least one of the second seal layer and the third seal layer comprises from about 40-55 mol % boron oxide.
10. The vacuum insulating panel of claim 7 , wherein the at least one of the second seal layer and the third seal layer comprises from about 0-20 mol % titanium oxide.
11. The vacuum insulating panel of claim 6 , wherein the at least one of the second seal layer and the third seal layer comprises at least three times more boron oxide than bismuth oxide in terms of mol %.
12. The vacuum insulating panel of claim 6 , wherein the at least one of the second seal layer and the third seal layer comprises at least four times more boron oxide than bismuth oxide in terms of mol %.
13. The vacuum insulating panel of claim 6 , wherein the at least one of the second seal layer and the third seal layer comprises more boron oxide than bismuth oxide in terms of wt. %.
14. The vacuum insulating panel of claim 6 , wherein the at least one of the second seal layer and the third seal layer comprises, in terms of mol %, from about 4-9% bismuth oxide, from about 40-55% boron oxide, from about 15-35% silicon oxide, and from about 3-12% titanium oxide.
15. The vacuum insulating panel of claim 1 , wherein at least one of the second seal layer and the third seal layer has an average particle size (D50) of from about 2-15 μm.
16. The vacuum insulating panel of claim 1 , wherein at least one of the second seal layer and the third seal layer has an average particle size (D50) of from about 3-8 μm.
17. The vacuum insulating panel of claim 1 , wherein a thermal conductivity of the second seal layer is greater than a thermal conductivity of the first seal layer.
18. The vacuum insulating panel of claim 17 , wherein the second seal layer has a thermal conductivity of from 1.0 to 1.90 W/mK, and the first seal layer has a thermal conductivity of from 0.80 to 1.00 W/mK.
19. The vacuum insulating panel of claim 17 , wherein the second seal layer has a thermal conductivity of from about 1.10 to 1.50 W/mK, and the first seal layer has a thermal conductivity of from about 0.80 to 0.95 W/mK.
20. The vacuum insulating panel of claim 1 , wherein the first seal layer has a density of from about 2.8-4.0 g/cm 3 , the second seal layer has a density of from about 3.0-4.2 g/cm 3 , the third seal layer has a density of from about 3.0-4.2 g/cm 3 , and wherein the density of the second and/or third seal layer is at least about 0.20 g/cm 3 greater than the density of the first seal layer.
21. The vacuum insulating panel of claim 1 , wherein the second and third seal layers each have a bridging oxygen (BO) content of at least about 80%.
22. The vacuum insulating panel of claim 1 , wherein the second and third seal layers each have a bridging oxygen (BO) content of at least about 85%.
23. The vacuum insulating panel of claim 1 , wherein the first seal layer comprises tellurium oxide and vanadium oxide, and by wt. % comprises more tellurium oxide than vanadium oxide.
24. The vacuum insulating panel of claim 1 , wherein the first seal layer comprises from about 40-70 wt. % tellurium oxide.
25. The vacuum insulating panel of claim 24 , wherein from about 60-95% of Te in the first seal layer is in a form of TeO 3 , and from about 3-35% of Te in the first seal layer is in a form of TeO 4 .
26. The vacuum insulating panel of claim 25 , wherein the tellurium oxide further comprises TeO 3+1 , and wherein the first seal layer comprises more TeO 3 than TeO 3+1 by wt. %.
27. The vacuum insulating panel of claim 23 , wherein the vanadium oxide comprises VO 2 and V 2 O 5 , and wherein more V in the first seal layer is in a form of VO 2 than V 2 O 5 .
28. The vacuum insulating panel of claim 1 , wherein the first seal layer is a main seal layer, and the second and third seal layers are primer layers.
29. The vacuum insulating panel of claim 1 , wherein for at least one location of the seal, the first seal layer has a first thickness, the second seal layer has a second thickness, and the third seal layer has a third thickness; and wherein the first thickness is greater than the second thickness and less than the third thickness.
30. The vacuum insulating panel of claim 1 , wherein the seal is substantially lead-free.
31. The vacuum insulating panel of claim 1 , wherein the first seal layer has a physical thickness of from about 40-100 μm.
32. The vacuum insulating panel of claim 31 , wherein the second seal layer has a physical thickness of from about 20-70 μm, and the third seal layer has a physical thickness of from about 100-220 μm.
33. The vacuum insulating panel of claim 1 , wherein the second seal layer has a melting point (Tm) at least 100 degrees C. higher than a melting point of the first seal layer.
34. The vacuum insulating panel of claim 1 , wherein the second seal layer has a melting point (Tm) at least 150 degrees C. higher than a melting point of the first seal layer.
35. The vacuum insulating panel of claim 1 , wherein the first and second substrates comprise tempered glass substrates or heat strengthened glass substrates.
36. The vacuum insulating panel of claim 1 , wherein the seal is a hermetic edge seal of the vacuum insulating panel.
37. The vacuum insulating panel of claim 1 , wherein the panel is configured for use in a window.
38. A vacuum insulating panel comprising:
a first glass substrate;
a second glass substrate;
a plurality of spacers provided in a gap between at least the first and second substrates, wherein the gap is at pressure less than atmospheric pressure;
a seal provided at least partially between at least the first and second substrates, the seal comprising a first seal layer and a second seal layer, wherein the second seal layer is located between the first seal layer and one of the glass substrates;
wherein a coefficient of thermal expansion (CTE) of the second seal layer is greater than a CTE of the first seal layer; and
wherein the CTE of the first seal layer is from about 7.0 to 7.9×10 −6 mm/(mm*deg. C.), the CTE of the second seal layer is from about 8.0 to 8.8×10 −6 mm/(mm*deg. C.), the CTE of the first glass substrate is from about 8.7 to 9.3×10 −6 mm/(mm*deg. C.), and the CTE of the second glass substrate is from about 8.7 to 9.3×10 −6 mm/(mm*deg. C.).
39. The vacuum insulating panel of claim 38 , wherein the CTE of the first seal layer is from about 7.2 to 7.9×10 −6 mm/(mm*deg. C.).
40. The vacuum insulating panel of claim 38 , wherein the CTE of the first seal layer is about 7.6×10 −6 mm/(mm*deg. C.).
41. The vacuum insulating panel of claim 38 , wherein CTE of the second seal layer is from about 8.3 to 8.6×10 −6 mm/(mm*deg. C.).
42. The vacuum insulating panel of claim 38 , wherein CTE of the first and second glass substrates is from about 8.8 to 9.2×10 −6 mm/(mm*deg. C.).
43. The vacuum insulating panel of claim 38 , wherein the second seal layer comprises from about 1-20 mol % bismuth oxide and from about 20-65 mol % boron oxide, and comprises at least two times more boron oxide than bismuth oxide in terms of mol %.
44. The vacuum insulating panel of claim 43 , wherein the first seal layer comprises tellurium oxide and vanadium oxide.
45. The vacuum insulating panel of claim 38 , wherein the first seal layer comprises from about 20-80 wt. % tellurium oxide, the tellurium oxide comprising TeO 4 and TeO 3 , and wherein the first seal layer comprises more TeO 3 than TeO 4 by wt. %.