GLASS LAMINATES CONTAINING LOW EXPANSION GLASS

Abstract

Apparatus and related methods are provided for a laminate glass article, comprising: a first layer of a first material, the first sheet having a thickness less than 2 mm and a first coefficient of thermal expansion (CTE) measured over a range of from 0-300 C.; a second layer of a second material, the second sheet having a thickness greater than 2 mm and a second CTE greater than the first CTE; and a polymer interlayer between the first and second layers, wherein the first glass sheet has a surface compressive stress greater than 4 MPa.

Claims

1. A laminate glass article, comprising: a. a first layer of a first transparent or translucent material, the first sheet having a thickness less than 2 mm and a first coefficient of thermal expansion (CTE) measured over a range of from 0-300 C.; b. a second layer of a second transparent or translucent material, the second sheet having a thickness greater than 2 mm and a second CTE greater than the first CTE; and c. a polymer interlayer positioned between the first layer and the second layer and configured to attach the first layer to the second layer, d. wherein the first glass sheet has a surface compressive stress greater than 4 MPa.

2. The laminate of claim 1, wherein the polymer interlayer comprises: a polyvinyl alcohol (PVA), a polyvinyl butyral (PVB), an ethylene-vinyl acetate (EVA), an ionomer, a polyvinyl acetal, or a thermoplastic polyurethanes (TPU).

3. The laminate of claim 1, wherein the first CTE is less than 6010-7/ C.

4. The laminate of claim 1, wherein the second CTE is greater than 7510-7/ C.

5. The laminate of claim 1, wherein the first glass sheet is an alkaline earth boro-aluminosilicate glass.

6. The laminate of claim 1, wherein the second glass sheet is a soda lime silicate glass.

7. The laminate of claim 1, wherein the second glass sheet has a thickness of 2 mm to not greater than 6 mm.

8. The laminate of claim 1, wherein the first glass sheet has a thickness of 2 mm to not less than 0.5 mm.

9. A fenestration product, comprising: a. a glass laminate article having: i. a first layer of a first transparent or translucent material, the first sheet having a thickness less than 2 mm and a first coefficient of thermal expansion (CTE) measured over a range of from 0-300 C.; ii. a second layer of a second transparent or translucent material, the second sheet having a thickness greater than 2 mm and a second CTE greater than the first CTE; and iii. a polymer interlayer between the first layer and the second layer; and b. a frame supporting the laminate edges in a plane, c. wherein, via the frame, the first glass sheet of the glass laminate article has an increased surface compressive stress when mounted in the frame than when unmounted.

10. The fenestration product of claim 9, wherein the frame is configured with a seal member, wherein the seal is configured to provide compressive engagement to the edge of the laminate structure.

11. The fenestration product of claim 9, wherein the frame is configured to retain the glass laminate article in restrictive engagement to retain the compressive stress on the first layer.

12. The fenestration product of claim 9, wherein the interlayer is configured with a thickness of 0.5 mm to not greater than 2.9 mm thick.

13. The fenestration product of claim 9, wherein the fenestration product comprises a linear area of 4 feet by 8 feet.

14. The fenestration product of claim 9, wherein the fenestration product comprises a linear area of 8 feet by 10 feet.

15. The fenestration product of claim 9, wherein the fenestration product comprises a linear area of 10 feet by 12 feet.

16. The fenestration product of claim 1, wherein the fenestration product is configured as: a window, a door, a curtain wall, a skylight, or a roof window.

17. The fenestration product of claim 1, wherein the fenestration product comprises a safety glazing, when measured in accordance with: ANSI Z97.1 or EN 12600 standards.

18. A method, comprising: a. assembling laminate component layers into a stack, wherein the component layers include: b. a first layer of a first transparent or translucent material, the first sheet having a thickness less than 2 mm and a first coefficient of thermal expansion (CTE) measured over a range of from 0-300 C.; c. a second layer of a second transparent or translucent material, the second sheet having a thickness greater than 2 mm and a second CTE greater than the first CTE; and d. a polymer interlayer positioned between the first layer and the second layer and configured to attach the first layer to the second layer, e. removing any entrapped air from the stack to make curable stack; and f. curing the curable stack to make a glass laminate article, wherein the first glass sheet has a surface compressive stress greater than 4 MPa.

19. The method of claim 18, wherein curing comprises laminating at a temperature sufficient to enable the polymer interlayer to cure, thus bonding the first layer to the second layer.

20. The method of claim 18, wherein the glass laminate article is configured as a safety glazing, when measured in accordance with: ANSI Z97.1 or EN 12600 standards.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0033] These and other features, aspects and advantages of the present disclosure are better understood when the following detailed description of the disclosure is read with reference to the accompanying drawings:

[0034] FIG. 1 depicts a plot of measured and modeled stress on boro-aluminosilicate glass in a laminate, where the compressive stress is attributed to the lamination process, in accordance with one or more embodiments of the present disclosure.

[0035] FIG. 2 depicts the results of computer modeled finite element modeled stress on the boro-aluminosilicate glass, when configured in a 4 foot8 foot laminate, where the compressive stress is attributed to the lamination process, in accordance with one or more embodiments of the present disclosure.

[0036] FIG. 3 depicts the results of computer modeled finite element analysis, depicting the modeled stress on boro-aluminosilicate glass in a 4 foot8 foot laminate with the edges fixed in a plane, in accordance with one or more embodiments of the present disclosure.

[0037] FIG. 4A through FIG. 4D depict schematic cut-away side views of the glass laminate article and IGU having a glass laminate article, frame, and coating(s), in accordance with one or more embodiments of the present disclosure.

[0038] FIG. 5 depicts a flow chart of an embodiment of a lamination process employable to place the boro-aluminosilicate glass into compression when configured in a laminate with an interlayer bonding the boro-aluminosilicate glass layer to a second glass layer having a different thickness and different CTE, in accordance with one or more embodiments of the present disclosure.

DETAILED DESCRIPTION OF THE DRAWINGS

[0039] In the following detailed description, for purposes of explanation and not limitation, example embodiments disclosing specific details are set forth to provide a thorough understanding of various principles of the present disclosure. However, it will be apparent to one having ordinary skill in the art, having had the benefit of the present disclosure, that the present disclosure may be practiced in other embodiments that depart from the specific details disclosed herein. Moreover, descriptions of well-known devices, methods and materials may be omitted so as not to obscure the description of various principles of the present disclosure. Finally, wherever applicable, like reference numerals refer to like elements.

Example

[0040] Experimentally, 12 inch12 inch laminates were made from 4.76 mm heat strengthened soda lime glass (SLG) (second layer) and 0.7 mm boro-aluminosilicate glass (first layer). The stress in the first layer was then measured using a SCALP instrument [https://www.glasstress.com/web/]. When the lamination foil between the two glasses was 90 mil SentryGlas the exposed first layer surface had an average stress of 4.35 MPa (compressive). For a 90 mil PVB (Trosifol Clear) foil, which transmits less stress to the first layer surface, the surface stress was 3.2 MPa. (1 mil=0.001 inch=0.0254 mm, thus 90 mil=2.29 mm.)

[0041] Without being bound by any particular mechanism and/or theory, the first layer's compressive stress in laminate form is believed to be attributable to the difference between the coefficient of thermal expansion of boro-silicate glass (the first layer) (e.g. which is approximately 3210.sup.7/K) and the coefficient of thermal expansion of SLG (the second layer (e.g. which is approximately 9010.sup.7/K). The two stacks of laminate components were laminated at temperatures above 100 C. and cooled to room temperature. Upon cooling, the second layer SLG will contract more than the boro-aluminosilicate glass, with the resulting process-induced stresses putting the boro-aluminosilicate glass into compression when retained in laminate form.

[0042] For comparison, when the second layer of boro-aluminosilicate glass is replaced with 0.7 mm SLG (comparative example second layer), the resulting laminate of similar CTE glasses (first layer and comparative example second layer) has <1 MPa compressive stress in the thin ply. However, it is noted that this is within the measurement error for a stress-free part.

[0043] Measurements of other parts, and finite element simulation of larger parts, are shown in FIG. 1. Referring to FIG. 1, the surface compression appears to increase with glass laminate size. At around 4 foot8 foot size, the modeled compressive stress is around 20 MPa, and can be as high as 25 MPa, which is comparable to the stress of heat strengthened thick SLG (24 MPa per ASTM C1048).

[0044] In addition to putting the thin glass ply under compression, the difference in expansion results in spherical out-of-plane distortion, or bow, in the laminate. The compressive stress on the second layer, thin glass ply, can therefore be further increased by mechanically flattening the laminate. As shown in FIG. 1, 989 mm1256 mm laminates (first layer 4.76 mm SLG/interlayer 105 mil SentryGlas/second layer 0.7 mm boro-aluminosilicate) were measured to have 49 MPa surface compression, as measured in the (outer-facing) surface of the second layer. (105 mil=2.67 mm thickness interlayer.)

[0045] After mechanically flattening the laminate glass article by applying pressure at the panel center, the compression measured in the (outer-facing) surface of the second layer increased to 1724 MPa. This further increases the potential load resistance of the laminate, while having the added benefit of reducing optical distortion, a desirable attribute in a fenestration product with architectural applications and/or other products.

[0046] In practice, the flattening can be achieved by mounting the glass laminate article laminate in a frame (e.g. configuring the glass laminate article in a frame, and providing restrictive engagement to the glass laminate article via the frame for a fenestration application). Confining the edges of the glass laminate article to a plane, via the frame (with an optional seal member) has the effect of reducing overall bow and hence increasing compressive stress in the second layer (e.g. thin ply). FIG. 3 shows modeling of the 4 foot8 foot laminate of FIG. 2 after requiring the laminate edges have minimal deflection. The compressive stress, as measured in the (outer-facing) surface of the second layer, increases from 2025 MPa to 2536 MPa.

[0047] FIGS. 4A-4D depicts various embodiments of the glass laminate article and fenestration product, in accordance with one or more aspects of the present disclosure.

[0048] Referring to FIG. 4A, a glass laminate article 10 is depicted. The glass laminate article 10 includes a first layer 12, a second layer 14, and an interlayer 16, configured between the first layer 12 and second layer 14 and attaching/adhering the two together to form the laminate glass article 10. Also, the edge(s) 20 are denoted.

[0049] Referring to FIG. 4B, the glass laminate article 10 of FIG. 4A is depicted in a window configuration, shown as 28. The glass laminate article 10 includes a frame 18 configured around the edges of the laminate article 10, with a seal member 22 positioned between the frame 18 and the edge 20 to promote compressive engagement and/or retention in a plane configuration. FIG. 4B depicts a second coating 24 on the outer surface of the first layer 12.

[0050] Referring to FIG. 4C, the glass laminate article 10 of FIG. 4A is depicted in a window configuration, shown as 28. The glass laminate article 10 includes a frame 18 configured around the edges of the laminate article 10, with a seal member 22 positioned between the frame 18 and the edge 20 to promote compressive engagement and/or retention in a plane configuration. FIG. 4C depicts a first coating 26 on the outer surface of the second layer 14.

[0051] Referring to FIG. 4D, the glass laminate article 10 of FIG. 4A is depicted in a window configuration, shown as 28. The glass laminate article 10 includes a frame 18 configured around the edges of the laminate article 10, with a seal member 22 positioned between the frame 18 and the edge 20 to promote compressive engagement and/or retention in a plane configuration. FIG. 4D depicts a first coating 26 on the outer surface of the second layer 14 and a second coating 24 on the outer surface of the first layer 12.

[0052] As some non-limiting examples, the coating includes: a low emissivity coating, an anti-reflective coating; a tint coating; an easy clean coating; or an anti-bird strike coating. In some embodiments, the coating is a partial coating. In some embodiments, the coating is a full coating. In some embodiments (e.g. anti-bird strike coating), the coating is patterned along discrete portions of the surface.

[0053] For example, the low emissivity coating can be comprised of a combination of metals and oxides, including non-limiting examples of silicon nitride, metallic silver, silicon dioxide, tin oxide, zirconium oxide, and/or combinations thereof, to name a few.

[0054] FIG. 5 depicts a method of making a glass laminate article. As shown, the lamination process includes assembling the laminate component layers into a stack. The various component layers, including a first layer, an interlayer, and a second layer, are placed into contact with one another to form the stack.

[0055] Next, the lamination process includes removing any entrapped or entrained air between the various layers of the stack to form a curable stack. Non-limiting examples of air removal include: nip rolling, using an evacuation pouch, vacuuming via at least one vacuum ring, or a laminating via a flatbed laminator.

[0056] Lamination includes the following steps: raising the temperature of the stack to an elevated temperature (sufficient to cure the stack); curing the stack to adhere the first layer to the second layer via the interlayer, thus forming a laminated glass article; and cooling the laminated glass article to near room temperature.

[0057] Many variations and modifications may be made to the above-described embodiments of the disclosure without departing substantially from the spirit and various principles of the disclosure. All such modifications and variations are intended to be included herein within the scope of this disclosure and protected by the following claims.

[0058] Ranges can be expressed herein as from about one particular value, and/or to about another particular value. When such a range is expressed, another embodiment includes from the one particular value and/or to the other particular value. Similarly, when values are expressed as approximations, by use of the antecedent about, it will be understood that the particular value forms another embodiment. It will be further understood that the endpoints of each of the ranges are significant both in relation to the other endpoint, and independently of the other endpoint. As a non-limiting example, about means less than 10% of the referenced value.

[0059] Directional terms as used hereinfor example up, down, right, left, front, back, top, bottomare made only with reference to the figures as drawn and are not intended to imply absolute orientation.

[0060] Unless otherwise expressly stated, it is in no way intended that any method set forth herein be construed as requiring that its steps be performed in a specific order. Accordingly, where a method claim does not actually recite an order to be followed by its steps, or it is not otherwise specifically stated in the claims or descriptions that the steps are to be limited to a specific order, it is in no way intended that an order be inferred, in any respect. This holds for any possible non-express basis for interpretation, including matters of logic with respect to arrangement of steps or operational flow; plain meaning derived from grammatical organization or punctuation; the number or type of embodiments described in the specification.

[0061] As used herein, the singular forms a, an and the include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to a component includes aspects having two or more such components, unless the context clearly indicates otherwise.