Glass substrate with coefficient of thermal expansion to reduce laminate bow, improved recyclability, and ability to be fusion formed, insulated glass unit incorporating same, and method of making the same

Abstract

A glass substrate including (on an oxide basis, and in mole percentage): from 70.0 to 80.0 SiO2; from 1.60 to 9.20 Al2O3; from 2.80 to 12.50 Na2O; from 0 to 10.00 MgO; from 0 to 8.50 CaO; from 0 to 8.00 SrO; from 0 to 2.00 ZnO; from 0 to 6.70 K2O; and from 0 to 0.20 SnO2. The glass composition is substantially free of B2O3. The glass substrate exhibits a coefficient of thermal expansion at 150 °C that is within a range of from 5.5 ppm / °C to 7.0 ppm / °C. The glass substrate exhibits a density of less than 2.60 g / cm3. The glass substrate exhibits a viscosity of 200 Poise at a temperature of less than 1700 °C. The glass substrate exhibits a liquidus viscosity that is greater than 150,000 Poise.

Description

GLASS SUBSTRATE WITH COEFFICIENT OF THERMAL EXPANSION TO REDUCE LAMINATE BOW, IMPROVED RECYCLABILITY, AND ABILITY TO BE FUSION FORMED, INSULATED GLASS UNIT INCORPORATING SAME, AND METHOD OF MAKING THE SAMECROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of priority under 35 U.S.C. § 119 of U.S. Provisional Application No. 63 / 638,710 filed April 25, 2024, the content of which is incorporated herein by reference in its entirety.TECHNICAL FIELD

[0002] The disclosure pertains to a glass substrate with an alkali aluminosilicate glass composition lacking B2O3 and exhibiting a coefficient of thermal expansion suitable for lamination with thicker soda lime glass, a relatively low density, and a liquidus viscosity and temperature at a viscosity of 200 Poise that make the glass substrate suitable for fusion forming processes.BACKGROUND

[0003] Insulated glass units (“IGUs”) include a first pane of glass separated by a second pane of glass. Sometimes the second pane of glass is a laminate of two glass sheets. Often, the first pane of glass, which is intended to be exposed to the external environment, is soda lime glass and is thermally tempered to increase resistance to damage from impact events (hail, birds, etc.). The second pane of glass, which is intended to be exposed to an interior environment, is sometimes a laminate of two relatively thick layers of soda lime glass. Reasons for the laminate structure can be to prevent the second pane from shattering and falling to the ground upon an impact event (one layer, although shattered, remains stuck to the other layer) or to filter ultraviolet light, among other reasons.

[0004] Because of the use of relatively thick soda lime glass, both at the first pane and for both layers of the second pane, the IGU can be relatively heavy. Heavy IGUs mean suboptimal shipping costs, as well as suboptimal manufacturing costs and environmental impact due to suboptimal use of raw materials. Thus, there are incentives to reduce the weight of the IGU. Reducing the weight of the glass layer of the laminate of the second pane facing the interior environment can be a target.

[0005] However, there is a problem in that recycling constraints, compatibility with the remaining layer of soda lime glass in the laminate of the second pane, and manufacturing limitations all limit potential glass compositions that can be utilized to form the layer of laminate of the second pane. More particularly, recyclers of soda lime glass generally forbidincluding glass that includes boron oxide (B2O3). One reason to forbid the presence of glass that includes B2O3 is that, upon melting of the glass during recycling, the B2O3 is volatile and adversely affects the equipment used to melt the glass. As for compatibility with the remaining layer of soda lime glass in the laminate of the second pane, the larger the disparity in the coefficients in thermal expansion (at the lamination temperature) between the two layers of the laminate, the greater the bow in the laminate that can result upon cooling. The bow should be limited or non-existent. Specifically, it is desirable to minimize the bow because the presence of bow can complicate transport of the laminate by rollers, can induce undesirable stresses within the panes of the laminate that limit their strength, and / or can cause the IGU to show optical distortions. As for manufacturing limitations, modern IGUs can be quite wide but also quite thin, and manufacturing equipment and processes to make glass layers of such dimensions can be limited to glass compositions of a certain minimum viscosity in the molten state.SUMMARY

[0006] The present disclosure addresses that problem with a glass composition that lacks B2O3 but is otherwise formulated (i) to exhibit a liquidus viscosity and temperature at a viscosity of 200 Poise that render the glass composition suitable for fusion formation and therefore relatively thin, wide, and long glass substrates, (ii) with a coefficient of thermal expansion at lamination temperatures that resist generating a bow when a glass substrate of the glass composition is laminated to a thicker layer of soda lime glass, and (iii) with a density that is relatively low resulting in less product weight. The following summary is a brief description of certain aspects of the present disclosure. The summary should not be considered as limiting of the breadth, scope, or applicability of the present disclosure.

[0007] According to a first aspect of the present disclosure, a glass substrate comprises: a glass composition comprising (on an oxide basis and in mole percentage): SiCh, within a range of from 74.0 to 78.0; AI2O3, within a range of from 3.00 to 5.70; R2O, within a range of from 7.00 to 11.30; and R’O, within a range of from 5.70 to 13.90; wherein, R2O is the sum of Na2O and K2O, with Na2O being within a range of from 7.10 to 11.25 and K2O being within a range of from 0.005 to 6.7; wherein, R’O is the sum of MgO, CaO, SrO, and BaO, with MgO being within a range of from 2.50 to 8.30, CaO being within a range of from 0.01 to 4.20, SrO being within a range of from 0 to 5.20, and BaO being within a range of from 0 to 0.10; wherein, R2O + CaO + SrO + BaO + ZnO - AI2O3 is within a range of from 8.70 to 11.64; and wherein, the glass composition is substantially free of B2O3.

[0008] According to a second aspect of the present disclosure, the glass substrate of the first aspect is presented, wherein in the glass composition, MgO / (R’O + ZnO) is within a range of from 0.350 to 0.700.

[0009] According to a third aspect of the present disclosure, the glass substrate of any one of the first through second aspects is presented, wherein in the glass composition, R2O - AI2O3 - MgO - CaO is within a range of from -4.30 to 0.

[0010] According to a fourth aspect of the present disclosure, the glass substrate of any one of the first through third aspects is presented, wherein the glass composition further comprises SnO2, Fe20s, TiO2, and Cl’.

[0011] According to a fifth aspect of the present disclosure, the glass substrate of any one of the first through fourth aspects further comprises a thickness within a range of from 0.5 mm to 1.0 mm.

[0012] According to a sixth aspect of the present disclosure, the glass substrate of any one of the first through fifth aspects further comprises: (i) a width that is greater than 90 cm; and (ii) a length that is greater than 100 cm.

[0013] According to a seventh aspect of the present disclosure, the glass substrate of any one of the first through sixth aspects is presented, wherein the glass substrate exhibits a coefficient of thermal expansion at 150 °C that is within a range of from 6.0 ppm / °C to 7.0 ppm / °C.

[0014] According to an eighth aspect of the present disclosure, the glass substrate of any one of the first through seventh aspects is presented, wherein the glass substrate exhibits a liquidus viscosity that is greater than 150,000 Poise.

[0015] According to a ninth aspect of the present disclosure, the glass substrate of any one of the first through eighth aspects is presented, wherein the glass substrate exhibits a viscosity of 200 Poise at a temperature of less than 1705 °C.

[0016] According to a tenth aspect of the present disclosure, the glass substrate of any one of the first through ninth aspects is presented, wherein the glass substrate exhibits a density of less than 2.55 g / cm3.

[0017] According to an eleventh aspect of the present disclosure, a glass substrate comprises: a glass composition comprising (on an oxide basis, and in mole percentage): SiCh, within a range of from 72.0 to 78.5; AI2O3, within a range of from 1.70 to 9.20; R2O, within a range of from 5.30 to 11.60; and R’O, within a range of from 5.70 to 13.90; wherein, R2O is the sum of Na2O and K2O, with Na2O being within a range of from 2.80 to 11.60 and K2O beingwithin a range of from 0.005 to 6.70; wherein, R’O is the sum of MgO, CaO, SrO, and BaO, with MgO being within a range of from 0.40 to 8.30, CaO being within a range of from 0.01 to 8.50, SrO being within a range of from 0 to 6.50, and BaO being within a range of from 0 to 0.10; and wherein, the glass composition is substantially free of B2O3.

[0018] According to a twelfth aspect of the present disclosure, the glass substrate of the eleventh aspect is presented, wherein in the glass composition, CaO / (R’O + ZnO) is within a range of from 0.004 to 0.620.

[0019] According to a thirteenth aspect of the present disclosure, the glass substrate of any one of the eleventh through the twelfth aspects is presented, wherein in the glass composition, SrO / (R’O + ZnO) is within a range of from 0 to 0.37.

[0020] According to a fourteenth aspect of the present disclosure, the glass substrate of any one of the eleventh through the thirteenth aspects is presented, wherein in the glass composition, (R’O + ZnO) / AI2O3 is within a range of from 1.00 to 4.00.

[0021] According to a fifteenth aspect of the present disclosure, the glass substrate of any one of the eleventh through the fourteenth aspects is presented, wherein in the glass composition, R’O + ZnO is within a range of from 5.70 to 14.00.

[0022] According to a sixteenth aspect of the present disclosure, the glass substrate of any one of the eleventh through the fifteenth aspects is presented, wherein the glass composition further comprises SnO2, Fe2O3, TiO2, and Cl’.

[0023] According to a seventeenth aspect of the present disclosure, the glass substrate of any one of the eleventh through the sixteenth aspects is presented, wherein in the glass composition, Na2O is within a range of from 7 to 11.6.

[0024] According to an eighteenth aspect of the present disclosure, the glass substrate of any one of the eleventh through the seventeenth aspects is presented, wherein in the glass composition, K2O is within a range of from 0.005 to 4.00.

[0025] According to a nineteenth aspect of the present disclosure, the glass substrate of any one of the eleventh through the eighteenth aspects is presented, wherein the glass substrate exhibits a density of less than 2.60 g / cm3.

[0026] According to a twentieth aspect of the present disclosure, the glass substrate of any one of the eleventh through the nineteenth aspects is presented, wherein (i) in the glass composition SrO is within a range of from 0 to 6.00, and (ii) the glass substrate exhibits a density of less than 2.55 g / cm3.

[0027] According to a twenty-first aspect of the present disclosure, the glass substrate of any one of the eleventh through the twentieth aspects is presented, wherein (i) in the glass composition, R’O is within a range of from 5.70 to 13.30; (ii) in the glass composition, SrO is within a range of from 0 to 3.60, and (iii) the glass substrate exhibits a density of less than 2.50 g / cm3.

[0028] According to a twenty-second aspect of the present disclosure, the glass substrate of any one of the eleventh through the twenty-first aspects is presented, wherein (i) in the glass composition, CaO is within a range of from 2.50 to 8.20; (ii) in the glass composition, SrO is within a range of from 0 to 2.40, and (iii) the glass substrate exhibits a density of less than 2.45 g / cm3.

[0029] According to a twenty-third aspect of the present disclosure, the glass substrate of any one of the eleventh through the twenty-second aspects is presented, wherein in the glass composition, SrO is within a range of from 0 to 1.20.

[0030] According to a twenty-fourth aspect of the present disclosure, the glass substrate of any one of the eleventh through the twenty-third aspects is presented, wherein in the glass composition, AI2O3, is within a range of from 1.70 to 6.00.

[0031] According to a twenty-fifth aspect of the present disclosure, the glass substrate of any one of the eleventh through the twenty-fourth aspects is presented, wherein the glass substrate exhibits a coefficient of thermal expansion at 150 °C that is within a range of from 4.8 ppm / °C to 7.6 ppm / °C.

[0032] According to a twenty-sixth aspect of the present disclosure, the glass substrate of any one of the eleventh through the twenty-fifth aspects is presented, wherein (i) in the glass composition, Na?O is within a range of from 7.10 to 11.25, and (ii) the glass substrate exhibits a coefficient of thermal expansion at 150 °C that is within a range of from 6.0 ppm / °C to 7.0 ppm / °C.

[0033] According to a twenty-seventh aspect of the present disclosure, the glass substrate of any one of the eleventh through the twenty-fifth aspects is presented, wherein (i) in the glass composition, R2O - AI2O3 - MgO - CaO is within a range of from -4.30 to 0, and (ii) the glass substrate exhibits a coefficient of thermal expansion at 150 °C that is within a range of from 6.0 ppm / °C to 7.0 ppm / °C.

[0034] According to a twenty-eighth aspect of the present disclosure, the glass substrate of any one of the eleventh through the twenty-seventh aspects is presented, wherein (i) in the glass composition, Na2O is within a range of from 7.20 to 9.90, and (ii) the glass substrateexhibits a coefficient of thermal expansion at 150 °C that is within a range of from 6.0 ppm / °C to 6.5 ppm / °C.

[0035] According to a twenty-ninth aspect of the present disclosure, the glass substrate of any one of the eleventh through the twenty-eighth aspects is presented, wherein the glass substrate exhibits a liquidus viscosity that is greater than 50,000 Poise.

[0036] According to a thirtieth aspect of the present disclosure, the glass substrate of any one of the eleventh through the twenty-eighth aspects is presented, wherein the glass substrate exhibits a liquidus viscosity that is greater than 150,000 Poise.

[0037] According to a thirty-first aspect of the present disclosure, the glass substrate of any one of the eleventh through the twenty-eighth aspects is presented, wherein the glass substrate exhibits a liquidus viscosity that is greater than 250,000 Poise.

[0038] According to a thirty-second aspect of the present disclosure, the glass substrate of any one of the eleventh through the thirty-first aspects is presented, wherein the glass substrate exhibits a viscosity of 200 Poise at a temperature of less than 1725 °C.

[0039] According to a thirty-third aspect of the present disclosure, the glass substrate of any one of the eleventh through the thirty-first aspects is presented, wherein the glass substrate exhibits a viscosity of 200 Poise at a temperature of less than 1650 °C.

[0040] According to a thirty-fourth aspect of the present disclosure, the glass substrate of any one of the eleventh through the thirty-first aspects is presented, wherein the glass substrate exhibits a viscosity of 200 Poise at a temperature of less than 1630 °C.

[0041] According to a thirty-fifth aspect of the present disclosure, the glass substrate of any one of the eleventh through the thirty-fourth aspects further comprises: a thickness within a range of from 0.5 mm to 1.0 mm.

[0042] According to a thirty-sixth aspect of the present disclosure, the glass substrate of any one of the eleventh through the thirty-fifth aspects further comprises: (i) a width that is greater than 90 cm; and (ii) a length that is greater than 100 cm.

[0043] According to a thirty-seventh aspect of the present disclosure, a glass substrate comprises: a glass composition comprising (on an oxide basis, and in mole percentage): SiCh, within a range of from 70.0 to 80.0; AI2O3, within a range of from 1.60 to 9.20; Na2O, within a range of from 2.80 to 12.50; MgO, within a range of from 0 to 10.00; CaO, within a range of from 0 to 8.50; SrO, within a range of from 0 to 8.00; ZnO, within a range of from 0 to 2.00; K2O, within a range of from 0 to 6.70; and SnCh, within a range of from 0 to 0.20; wherein, the glass substrate exhibits a coefficient of thermal expansion at 150 °C that iswithin a range of from 5.5 ppm / °C to 7.0 ppm / °C, wherein, the glass substrate exhibits a density of less than 2.60 g / cm3, wherein, the glass substrate exhibits a viscosity of 200 Poise at a temperature of less than 1700 °C, wherein, the glass substrate exhibits a liquidus viscosity that is greater than 150,000 Poise, and wherein, the glass composition is substantially free of B2O3.

[0044] According to a thirty-eighth aspect of the present disclosure, the glass substrate of the thirty-seventh aspect is presented, wherein (i) the glass substrate exhibits a coefficient of thermal expansion at 150 °C that is within a range of from 5.5 ppm / °C to 6.8 ppm / °C, (ii) the glass substrate exhibits a density of less than 2.50 g / cm3, (iii) the glass substrate exhibits a viscosity of 200 Poise at a temperature of less than 1650 °C, and (iv) wherein, the glass substrate exhibits a liquidus viscosity that is greater than 250,000 Poise.

[0045] According to a thirty-ninth aspect of the present disclosure, the glass substrate of the thirty-seventh aspect is presented, wherein (i) in the glass composition, SiCh is within a range of from 73.0 to 78.0, (ii) in the glass composition, AI2O3 is within a range of from 3.00 to 6.00, (iii) in the glass composition, Na2O is within a range of from 8.00 to 11.50, (iv) in the glass composition, MgO is within a range of from 2.00 to 8.50, (v) in the glass composition, CaO is within a range of from 0 to 4.50, (vi) in the glass composition, SrO is within a range of from 0 to 5.00, (vii) in the glass composition, ZnO is within a range of from 0 to 1.00, (viii) in the glass composition, K2O is within a range of from 0 to 2.00, (ix) in the glass composition, SnCh is within a range of from 0 to 0.10, (x) the glass substrate exhibits a coefficient of thermal expansion at 150 °C that is within a range of from 5.5 ppm / °C to 6.8 ppm / °C, (xi) the glass substrate exhibits a density of less than 2.50 g / cm3, (xii) the glass substrate exhibits a viscosity of 200 Poise at a temperature of less than 1630 °C, and (xiii) wherein, the glass substrate exhibits a liquidus viscosity that is greater than 250,000 Poise.

[0046] According to a fortieth aspect of the present disclosure, the glass substrate of the thirty-ninth aspect is presented, wherein the glass substrate exhibits a liquidus viscosity that is greater than 400,000 Poise.

[0047] According to a forty-first aspect of the present disclosure, an insulated glass unit comprises: (a) a first pane; and (b) a second pane separated from the first pane by a space, the second pane comprising a laminate comprising a first glass layer and a second glass layer, the first glass layer comprising soda lime glass and the second glass layer comprising a glass composition comprising (on an oxide basis and in mole percentage): SiCh, within a range of from 70.0 to 80.0; AI2O3, within a range of from 1.60; to 9.20; Na2O, within a range of from2.80 to 12.50; MgO, within a range of from 0 to 10.00; CaO, within a range of from 0 to 8.50; SrO, within a range of from 0 to 8.00; ZnO, within a range of from 0 to 2.00; K2O, within a range of from 0 to 6.70; and SnCh, within a range of from 0 to 0.20; wherein, the glass composition is substantially free of B2O3.

[0048] According to a forty-second aspect of the present disclosure, the insulated glass unit of the forty-first aspect is presented, wherein the glass composition of the second glass layer of the second pane comprises: SiCh, within a range of from 72.0 to 78.5; AI2O3, within a range of from 1.70 to 9.20; R2O, within a range of from 5.30 to 11.60; and R’O, within a range of from 5.70 to 13.90; wherein, R2O is the sum of Na2O and K2O, with Na2O being within a range of from 2.80 to 11.60 and K2O being within a range of from 0.005 to 6.7; and wherein, R’O is the sum of MgO, CaO, SrO, and BaO, with MgO being within a range of from 0.40 to 8.30, CaO being within a range of from 0.01 to 8.50, SrO being within a range of from 0 to 6.50, and BaO being within a range of from 0 to 0.10.

[0049] According to a forty-third aspect of the present disclosure, the insulated glass unit of the forty-second aspect is presented, wherein the glass composition of the second glass layer of the second pane comprises: SiO2 is within a range of from 74.0 to 78.0; AI2O3 is within a range of from 3.00 to 5.70; R2O is within a range of from 7.00 to 11.30; R’O is within a range of from 5.70 to 13.90; Na2O is within a range of from 7.1 to 11.25; MgO is within a range of from 2.50 to 8.30; CaO is within a range of from 0.01 to 4.20; SrO is within a range of from 0 to 5.20; and R2O + CaO + SrO + BaO + ZnO - AI2O3 is within a range of from 8.70 to 11.64.

[0050] According to a forty-fourth aspect of the present disclosure, the insulated glass unit of any one of the forty-first through the forty-third aspects is presented, wherein the first pane comprises soda lime glass.

[0051] According to a forty-fifth aspect of the present disclosure, the insulated glass unit of any one of the forty-first through the forty-fourth aspects is presented, wherein (i) the first glass layer of the second pane comprises a thickness within a range of from 2.0 mm to 8.0 mm, and (ii) the first pane comprises a thickness within a range of from 2.0 mm to 8.0 mm.

[0052] According to a forty-sixth aspect of the present disclosure, the insulated glass unit of any one of the forty-first through the forty-fifth aspects is presented, wherein the second glass layer of the second pane comprises a thickness within a range of from 0.5 mm to 1.0 mm.

[0053] According to a forty-seventh aspect of the present disclosure, the insulated glass unit of any one of the forty-first through the forty-sixth aspects is presented, wherein the secondglass layer of the second pane comprises: a width that is greater than 90 cm; and a length that is greater than 100 cm.

[0054] According to a forty-eighth aspect of the present disclosure, the insulated glass unit of any one of the forty-first through the forty-seventh aspects is presented, wherein the second glass layer of the second pane exhibits a coefficient of thermal expansion at 150 °C that is within a range of from 6.0 ppm / °C to 7.0 ppm / °C.

[0055] According to a forty-ninth aspect of the present disclosure, the insulated glass unit of any one of the forty-first through the forty-eighth aspects is presented, wherein the second glass layer of the second pane exhibits a liquidus viscosity that is greater than 150,000 Poise.

[0056] According to a fiftieth aspect of the present disclosure, the insulated glass unit of any one of the forty-first through the forty-ninth aspects is presented, wherein the second glass layer of the second pane exhibits a viscosity of 200 Poise at a temperature of less than 1725 °C.

[0057] According to a fifty-first aspect of the present disclosure, the insulated glass unit of any one of the forty-first through the fiftieth aspects is presented, wherein the second glass layer of the second pane exhibits a density of less than 2.55 g / cm3.

[0058] According to a fifty-second aspect of the present disclosure, a method of manufacturing a glass substrate comprises: a fusion forming step comprising causing a glass composition to flow in a molten state into a trough of an isopipe, overflow the through, and then flow over outer forming surfaces of the isopipe to converge at a root and form a glass ribbon; and a separating step comprising separating a glass substrate from the glass ribbon, wherein, the glass composition in the molten state comprises a temperature of less than 1705 °C, wherein, the glass composition in the molten state exhibits a viscosity that is greater than 50,000 Poise, and wherein, the glass composition comprises (on an oxide basis and in mole percentage): SiCh, within a range of from 70.0 to 80.0; AI2O3, within a range of from 1.60; to 9.20; Na2O, within a range of from 2.80 to 12.50; MgO, within a range of from 0 to 10.00; CaO, within a range of from 0 to 8.50; SrO, within a range of from 0 to 8.00; ZnO, within a range of from 0 to 2.00; K2O, within a range of from 0 to 6.70; and SnCh, within a range of from 0 to 0.20; wherein, the glass composition is substantially free of B2O3.

[0059] According to a fifty-third aspect of the present disclosure, the method of the fifty- second aspect is presented, wherein the glass composition comprises (on an oxide basis and in mole percentage): SiCh, within a range of from 72.0 to 78.5; AI2O3, within a range of from 1.70 to 9.20; R2O, within a range of from 5.30 to 11.60; and R’O, within a range of from 5.70to 13.90; wherein, R2O is the sum of Na20 and K2O, with Na20 being within a range of from 2.80 to 11.60 and K2O being within a range of from 0.005 to 6.7; and wherein, R’O is the sum of MgO, CaO, SrO, and BaO, with MgO being within a range of from 0.40 to 8.30, CaO being within a range of from 0.01 to 8.50, SrO being within a range of from 0 to 6.50, and BaO being within a range of from 0 to 0.10.

[0060] According to a fifty-fourth aspect of the present disclosure, the method of the fifty- third aspect is presented, wherein the glass composition comprises (on an oxide basis and in mole percentage): SiO2, within a range of from 74.0 to 78.0; AI2O3, within a range of from 3.00 to 5.70; R2O, within a range of from 7.00 to 11.30; and R’O, within a range of from 5.70 to 13.90; wherein, R2O is the sum of Na2O and K2O, within Na2O being within a range of from 7.1 to 11.25 and K2O being greater than or equal to 0.005; wherein, R’O is the sum of MgO, CaO, SrO, and BaO, with MgO being within a range of from 2.50 to 8.30, CaO being within a range of from 0.01 to 4.20, SrO being within a range of from 0 to 5.20, and BaO being within a range of from 0 to 0.10; and wherein, R2O + CaO + SrO + BaO + ZnO - AI2O3 is within a range of from 8.70 to 11.64.

[0061] According to a fifty-fifth aspect of the present disclosure, the method of any one of the fifty-second through fifty-fourth aspects further comprises: a laminating step comprising laminating the glass substrate to a glass layer comprising soda lime glass at a lamination temperature within a range of from 100 °C to 200 °C and thereby forming a glass pane; wherein, the glass substrate exhibits a coefficient of thermal expansion at 150 °C that is within a range of from 6.0 ppm / °C to 7.0 ppm / °C, and wherein, the glass substrate exhibits a density of less than 2.55 g / cm3.

[0062] According to a fifty-sixth aspect of the present disclosure, the method of any one of the fifty-second through fifty-fifth aspects further comprises: a recycling step comprising recycling the glass pane with soda lime glass to form recycled glass material.

[0063] Additional features and advantages will be set forth in the detailed description which follows, and in part will be readily apparent to those skilled in the art from that description or recognized by practicing the embodiments as described herein, including the detailed description which follows, the claims, as well as the appended drawings.

[0064] It is to be understood that both the foregoing general description and the following detailed description are merely exemplary and are intended to provide an overview or framework to understanding the nature and character of the claims.

[0065] The accompanying drawings are included to provide a further understanding of principles of the disclosure, and are incorporated in, and constitute a part of, this specification. The drawings illustrate one or more embodiment(s) and, together with the description, serve to explain, by way of example, principles and operation of the disclosure. It is to be understood that various features of the disclosure disclosed in this specification and in the drawings can be used in any and all combinations. By way of non-limiting examples, the various features of the disclosure may be combined with one another according to the following embodiments.BRIEF DESCRIPTION OF THE DRAWINGS

[0066] The following is a description of the figures in the accompanying drawings. The figures are not necessarily to scale, and certain features and certain views of the figures may be shown exaggerated in scale or in schematic in the interest of clarity and conciseness.

[0067] FIG. 1 is a perspective view of a glass substrate having a glass composition of the present disclosure, illustrating a first primary surface and a second primary surface;

[0068] FIG. 2 is an elevation view of the glass substrate of the present disclosure, illustrating the glass substrate further including a thickness;

[0069] FIG. 3 is an overhead plan view of an IGU including a pane, which is a laminate that includes the glass substrate of the present disclosure;

[0070] FIG. 4 is an elevation view of a cross-section of the IGU of FIG. 3 taken through line IV-IV of FIG. 3, illustrating the IGU further including a first pane separated from a second pane that includes the glass substrate laminated to another layer;

[0071] FIG. 5 is a schematic diagram of a method, illustrating a fusion forming step whereby a ribbon of glass is formed from the glass composition of the present disclosure and a separating step whereby the glass substrate of FIG. 1 is separated from the ribbon of glass;

[0072] FIG. 6 is a side view of a fusion forming apparatus used for the fusion formation step; and

[0073] FIG. 7 is a front view of both the fusion forming step and the separating step.DETAILED DESCRIPTION

[0074] Additional features and advantages will be set forth in the detailed description which follows and will be apparent to those skilled in the art from the description, or recognized by practicing the embodiments as described in the following description, together with the claims and appended drawings.

[0075] Referring to FIGS. 1-2, a glass substrate 10 includes a glass composition. The glass compositions described herein are on an oxide basis and in mole percentages. The glass composition includes (i) SiCh, within a range of from 70.0 to 80.0, (ii) AI2O3, within a range of from 1.60 to 9.20, (iii) Na2O, within a range of from 2.80 to 12.50, (iv) MgO, within a range of from 0 to 10.00, (v) CaO, within a range of from 0 to 8.00, (vi) SrO, within a range of from 0 to 8.00, (vii) ZnO, within a range of from 0 to 2.00, (viii) K2O, within a range of from 0 to 6.70, and (ix) SnCh, within a range of from 0 to 0.20. The mole percentages of the constituents of the glass composition can be determined via X-ray fluorescence.

[0076] In embodiments, the glass composition includes (i) SiCh, within a range of from 72.0 to 78.5, (ii) AI2O3, within a range of from 1.70 to 9.20, (iii) R2O, within a range of from 5.30 to 11.60, and (iv) R’O, within a range of from 5.70 to 13.90. For purposes of this disclosure, R2O means Na2O and K2O collectively, and the value for R2O is the sum of the individual values for Na2O and K2O in the glass composition. In addition, for purposes of this disclosure, R’O means MgO, CaO, SrO, and BaO collectively, and the value for R’O is the sum of the individual values for MgO, CaO, SrO, and BaO in the glass composition. Regarding R2O, the glass composition can include (i) Na2O within a range of from 2.80 to 11.60 and (ii) K2O within a range of from 0.005 to 6.7. Regarding R’O, the glass composition can include (i) MgO within a range of from 0.40 to 8.30, (ii) CaO within a range of from 0.01 to 8.50, (iii) SrO within a range of from 0 to 6.50, and (iv) BaO within a range of from 0 to 0.10. The glass composition provides one or more properties that help address the problem set forth in the Background, including at least a density that is reduced relative to soda lime glass.

[0077] Further, the glass composition is substantially free of B2O3. “Substantially free,” for purposes of this disclosure, means that the glass composition does not purposefully include the mentioned oxide (e.g., B2O3) but the same may be unintentionally present within the glass composition as a trace constituent because of manufacturing imperfections including raw material and equipment contamination. For example, the mentioned oxide could be present in amounts of 0.001 mole percent or less and the glass composition would be “substantially” free of the mentioned oxide. The glass composition lacking B2O3 provides benefits, as discussed below.

[0078] In embodiments, the glass composition includes (i) SiCh, within a range of from 74.0 to 78.0, (ii) AI2O3, within a range of from 3.00 to 5.70, (iii) R2O, within a range of from 7.00 to 11.30, with Na2O being within a range of from 7.11 to 11.25 and K2O being within a rangeof from 0.005 to 6.7, and (iv) R’O, within a range of from 5.70 to 13.90, with MgO being within a range of from 2.50 to 8.30, CaO being within a range of from 0.01 to 4.20, SrO being within a range of from 0 to 5.20, and BaO being within a range of from 0 to 0.10. In such embodiments, R2O + CaO + SrO + BaO + ZnO - AI2O3 is within a range of from 8.70 to 11.64. Stated another way, the sum of the mole percentages of R2O, CaO, SrO, BaO, and ZnO, less the mole percentage of AI2O3, in the composition is within a range of from 8.70 to 11.64. That range provides a balance between reducing the melting point of the glass composition and not increasing the density or the coefficient of thermal expansion of the glass composition too much. In addition to providing a reduced density compared to soda lime glass, these embodiments (and others) of the glass composition can exhibit a coefficient of thermal expansion (at 150 °C) that make the glass substrate 10 suitable for lamination with a layer of soda lime glass. Further, these embodiments (and others) of the glass composition can exhibit a liquidus viscosity and 200 Poise temperature that make the glass composition especially suitable for the fusion formation of the glass substrate 10 from the glass composition.

[0079] As mentioned, the glass composition includes SiCh and AI2O3. Silica, SiCh, represents the largest constituent, by mole percentage, in the glass composition and is a glass network former. As such, SiCh is the primary constituent of the resulting glass network of the glass composition. Aluminum oxide, AI2O3, likewise is a glass network former and is a constituent of the resulting glass network of the composition. In general, increasing the combined mole percentage of SiCh and AI2O3 decreases the density of the glass substrate 10 but at the expense of increased temperature that the glass composition exhibits at a viscosity of 200 Poise, which affects manufacturing possibilities. For purposes of this disclosure, these effects are balanced when the mole percentage of SiCh is within the range of from 70.0 to 80.0, while the mole percentage of AI2O3 is within the range of from 1.60 to 9.20, as stated. The mole percentage of SiCh in the glass composition can be 70.0, 71.0, 72.0, 72.5, 73.0, 73.5, 74.0, 74.5, 75.0, 75.5, 76.0, 76.5, 77.0, 77.5, 78.0, 78.5, 79.0, or 80.0, or within any range bound by any two of those values (e.g., from 73.0 to 78.0, from 72.0 to 78.5, from 74.0 to 78.0, from 75.5 to 77.0). The mole percentage of AI2O3 in the glass composition can be 1.60, 1.70, 2.00, 2.50, 3.00, 3.50, 4.00, 4.50, 5.00, 5.50, 5.70, 6.00, 6.50, 7.00, 7.50, 8.00, 8.50, 9.00, or 9.20, or within any range bound by any two of those values (e.g., from 3.00 to 6.00, from 1.60 to 7.00, from 1.70 to 9.20, from 3.00 to 5.70, from 1.70 to 6.00).

[0080] As mentioned, the glass composition includes R2O, which generally refers to alkali oxides as a group. For purposes of this disclosure, R2O is the sum solely of the alkali oxides Na2O and K2O, and both of those alkali oxide are present within the glass composition. In embodiments, the glass composition can include one or more other alkali oxide such as Li2O, Rb2O, and CS2O. However, in other embodiments, the glass composition is substantially free of one or more (or all of) Li2O, Rb2O, and CS2O. In general, for the glass composition of the present disclosure, increasing the mole percentage of R2O lowers the density of the glass substrate 10, while increasing the coefficient of thermal expansion of the glass substrate 10. For purposes this disclosure, these effects are balanced with the mole percentage of R2O being within the range of from 5.30 to 11.60, as mentioned. The mole percentage of R2O in the composition can be 5.30, 5.50. 6.00, 6.50, 7.00, 7.50, 8.00, 8.50, 9.00, 9.50, 10.00, 10.50, 11.00, 11.30, 11.50, or 11.60, or within any range bound by any two of those values (e.g., from 7.00 to 11.30, from 8.00 to 10.00, and so on). The mole percentage of Na2O can be within the range of from 2.80 to 12.50, as mentioned. The mole percentage of Na2O in the glass composition can be 2.80. 3.00, 3.50, 4.00, 4.50, 5.00, 5.50, 6.00, 6.50, 7.00, 7.10, 7.20,7.50, 8.00, 8.50, 9.00, 9.50, 9.90, 10.00, 10.50, 11.00, 11.25, 11.50, or 11.60, or within any range bound by any two of those values (e.g., from 8.00 to 11.50, from 2.80 to 11.60, from 7.10 to 11.25, from 7.20 to 9.90, and so on). The mole percentage of K2O can be within the range of from 0 to 6.7, as mentioned. The mole percentage of K2O in the glass composition can be 0, 0.005, 0.01, 0.05, 0.10, 0.50, 1.00, 1.50, 2.00, 2.50, 3.00, 3.50, 4.00, 4.50, 5.00,5.50, 6.00, 6.50, or 6.70, or within any range bound by any two of those values (e.g., from 0 to 2.00, from 0 to 4.00, from 0.005 to 1.00, from 0.005 to 1.50, and so on).

[0081] As mentioned, the glass composition includes R’O, which generally refers to alkaline earth oxides as a group. For purposes of this disclosure, R’O is the sum solely of the alkaline oxides MgO, CaO, SrO, and BaO. The glass composition could theoretically include one or more other of the remaining alkaline earth oxides such as BeO and RaO. However, in embodiments, the glass composition is substantially free of either or both of BeO and RaO. In general, for the glass composition of the present disclosure, increasing the mole percentage of R’O decreases the temperature at which the glass substrate 10 exhibits a viscosity of 200 Poise but increases the density of the glass substrate 10. For purposes this disclosure, these effects are balanced with the mole percentage of R’O being within the range of from 5.70 to 13.90, as mentioned. In embodiments, the mole percentage of R’O is 5.70, 6.00, 6.50, 7.00,7.50, 8.00, 8.50, 9.00, 9.50, 10.00, 10.50, 11.00, 11.50, 12.00, 12.50, 13.00, 13.30, 13.50, or13.90, or within any range bound by any two of those values (e.g., from 5.70 to 13.30, from6.50 to 12.50, and so on). The mole percentage of MgO can be within the range of from 0 to 10.00, as mentioned. The mole percentage of MgO can be 0.40, 0.50, 1.00, 1.50, 2.00, 2.50, 3.00, 3.50, 4.00, 4.50, 5.00, 5.50, 6.00, 6.50, 7.00, 7.50, 8.00, 8.30, 8.50, 9.00, 9.50, or 10.00, or within any range bound by any two of those values (e.g., from 2.00 to 8.50, from 0.40 to 8.30, from 2.50 to 8.30, from 4.50 to 7.00, and so on). The mole percentage of CaO can be within a range of from 0 to 8.50, as mentioned. The mole percentage of CaO can be 0, 0.01, 0.10, 0.50, 1.00, 1.50, 2.00, 2.50, 3.00, 3.50, 4.00, 4.50, 5.00, 5.50, 6.00, 6.50, 7.00, 7.50, 8.00, 8.20, or 8.50, or within any range bound by any two of those values (e.g., from 0 to 4.50, from 0 to 8.00, from 0.01 to 4.20, from 2.50 to 8.20, and so on). Strontium oxide, SrO, having a much larger density than say MgO, more greatly increases the density of the glass substrate 10 as the mole percentage of SrO increases. In embodiments, the mole percentage of SrO in the composition, as mentioned is within the range of from 0 to 8.00. The mole percentage of SrO in the glass composition can be 0, 0.50, 1.00, 1.20, 1.50, 2.00, 2.40, 2.50, 3.00, 3.50, 3.60, 4.00, 4.50, 5.00, 5.20, 5.50, 6.00, 6.50, 7.00, 7.50, or 8.00, or within any range bound by any two of those values (e.g., from 0 to 6.00, from 0 to 5.20, from 0 to 5.00, from 0 to 3.60, from 0 to 2.40, from 0 to 1.20, and so on). As mentioned, the mole percentage of BaO in the composition is within the range of from 0 to 0.10.

[0082] As mentioned, the glass composition can include ZnO. In embodiments, the mole percentage of ZnO in the glass composition is within a range of from 0 to 2.00. In embodiments, the mole percentage of ZnO in the glass composition is 0, 0.10, 0.20, 0.30, 0.40, 0.50, 0.60, 0.70, 0.80, 0.90, 1.00, 1.10, 1.20, 1.30, 1.40, 1.50, 1.60, 1.70, 1.80, 1.90, or 2.00, or within any range bound by any two of those values (e.g., from 0 to 1.00, from 0.10 to 0.60, from 0.20 to 1.60, and so on).

[0083] In embodiments, the ratio (R’O + ZnO + R2O) / AI2O3 is within a range of from 3.00 to 6.80. For example, the ratio (R’O + ZnO + R2O) / AI2O3 can be 3.00, 3.50, 4.00, 4.50, 5.00, 5.50, 6.00, 6.50, 6.80, or within any range bound by any two of those values (e.g., from3.50 to 6.50, from 5.00 to 6.80, and so on). In embodiments, the ratio R2O / (AI2O3 + MgO) is within a range of from 0.70 to 1.40. For example, the ratio R2O / (AI2O3 + MgO) can be 0.70, 0.80, 0.90, 1.00, 1.10 1.20, 1.30, 1.40, or within any range bound by any two of those values (e.g., 0.80 to 1.30, from 0.90 to 1.10, and so on). As mentioned, in embodiments, R2O + CaO + SrO + BaO + ZnO - AI2O3 is within a range of from 8.70 to 11.64. For example, R2O + CaO + SrO + BaO + ZnO - AI2O3 can be 8.70, 8.80, 8.90, 9.00, 9.10, 9.20, 9.30, 9.40,9.50, 9.60, 9.70, 9.80, 9.90, 10.00, 10.10, 10.20, 10.30, 10.40, 10.50, 10.60, 10.70, 10.80, 10.90, 11.00, 11.10, 11.20, 11.30, 11.40, 11.50, 11.60, 11.64, or within any range bound by any two of those values (e.g., from 9.00 to 11.40, from 9.80 to 10.60, and so on). In embodiments, R2O + CaO + SrO + BaO + ZnO - AI2O3 - MgO is within a range of from 0.60 to 7.20. For example, R2O + CaO + SrO + BaO + ZnO - AI2O3 - MgO can be 0.60, 1.00,1.50, 2.00, 2.50, 3.00, 3.50, 4.00, 4.50, 5.00, 5.50, 6.00, 6.50, 7.00, 7.20, or within any range bound by any two of those values (e.g., from 1.00 to 2.00, from 1.50 to 7.00, and so on). In embodiments, the ratio (R’O + ZnO) / AI2O3 is within a range of from 1.00 to 4.00. For example, the ratio (R’O + ZnO) / AI2O3 can be 1.00, 1.25, 1.50, 1.75, 2.00, 2.25, 2.50, 2.75, 3.00, 3.25, 3.50, or within any range bound by any two of those values (e.g., from 1.25 to2.50, from 2.25 to 3.00, and so on). All the relationships expressed in this paragraph are thought, without being bound by theory, to balance lowering the melting point of the glass composition by limiting any concomitant increase in density and increasing the coefficient of thermal expansion of the glass composition.

[0084] In embodiments, SiO2+ MgO is within a range of from 78.00 to 83.50. For example, SiO2+ MgO can be 78.00 78.50, 79.00, 79.50, 80.00, 80.50, 81.00, 81.50, 82.00, 82.50, 83.00, 83.50, or within any range bound by any two of those values (e.g., from 79.00 to81.50, from 80.50 to 83.00, and so on). That relationship is thought, without being bound by theory, to make the glass composition in an advantageous pocket near the cotectic of cristobalite and aluminosilicates.

[0085] In embodiments, the ratio MgO / (R’O + ZnO) is within a range of from 0.350 to 0.700. For example, the ratio MgO / (R’O + ZnO) can be 0.350, 0.400, 0.450, 0.500, 0.550, 0.600, 0.650, 0.700, or within any range bound by any two of those values (e.g., from 0.400 to 0.450, from 0.450 to 0.650, and so on). In embodiments, the ratio CaO / (R’O + ZnO) is within a range of from 0.004 to 0.620. For example, the ratio CaO / (R’O + ZnO) can be 0.004, 0.050, 0.100, 0.150, 0.200, 0.250, 0.300, 0.350, 0.400, 0.450, 0.500, 0.550, 0.600, 0.620, or within any range bound by any two of those values (e.g., from 0.050 to 0.500, from 0.250 to 0.600, and so on). In embodiments, the ratio SrO / (R’O + ZnO) is within a range of from 0 to 0.370. For example, the ratio SrO / (R’O + ZnO) can be 0, 0.050, 0.100, 0.150, 0.200, 0.250, 0.300, 0.350, 0.370, or within any range bound by any two of those values (e.g., from 0.050 to 0.150, from 0.200 to 0.350, and so on). In embodiments, the ratio (CaO + SrO + BaO) / AI2O3 is within a range of from 0.55 to 1.75. For example, the ratio (CaO + SrO + BaO) / Al2O3can be 0.55, 0.60, 0.70, 0.80, 0.90, 1.00, 1.10, 1.20, 1.30, 1.40, 1.50, 1.60, 1.70,I.75, or within any range bound by any two of those values (e.g., from 1.10 to 1.60, from 0.70 to 1.70, and so on). All the relationships expressed in this paragraph are thought, without being bound by theory, to increase the stability of alkaline earth alumino silicates of the glass composition without suboptimally affecting the other properties of the glass composition of the present disclosure.

[0086] In embodiments, R’O + ZnO is within a range of from 5.50 to 14.00. For example, R’O + ZnO can be 5.50, 6.00, 6.50, 7.00, 7.50, 8.00, 8.50, 9.00, 9.50, 10.00, 10.50, 11.00,I I.50, 12.00, 12.50, 13.00, 13.50, 14.00, or within any range bound by any two of those values (e.g., from 8.00 to 13.50, from 7.00 to 12.50, and so on). In embodiments, R2O - AI2O3 is within a range of from 4.60 to 6.10. For example, R2O - AI2O3 can be 4.60, 4.70, 4.80, 4.90, 5.00, 5.10, 5.20, 5.30, 5.40, 5.50, 5.60, 5.70, 5.80, 5.90, 6.00, 6.10, or within any range bound by any two of those values (e.g., from 4.70 to 5.80, from 4.90 to 6.00, and so on). In embodiments, R2O - AI2O3 - MgO is within a range of from -2.90 to 3.10. For example, R2O - AI2O3 - MgO can be -2.90, -2.50, -2.00, -1.50, -1.00, -0.50, 0, 0.50, 1.00, 1.50, 2.00, 2.50, 3.00, 3.10, or within any range bound by any two of those values (from -2.50 to 1.50, from 0 to 3.00, and so on). In embodiments, R2O - AI2O3 - MgO - CaO is within a range of from -4.30 to 0. For example, R2O - AI2O3 - MgO - CaO is -4.25, -4.00, -3.50, - 3.00, -2.50, -2.00, -1.50, -1.00, -0.50, 0, or within any range bound by any two of those values (e.g., from -4.00 to -2.50, from -2.00 to -0.50, and so on). All the relationships expressed in this paragraph are thought, without being bound by theory, to help balance the properties of the glass composition of the present disclosure.

[0087] As mentioned, the glass composition can include SnCh, such as a fining agent. In embodiments, the mole percentage of SnCh in the glass composition is within a range of from 0 to 0.20. In embodiments, the mole percentage of SnCh in the glass composition is 0, 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, 0.10, 0.11, 0.12, 0.13, 0.14, 0.15, 0.16, 0.17, 0.18, 0.19, or 0.20, or within any range bound by any two of those values (e.g., from 0 to 0.10, from 0.04 to 0.08, from 0.11 to 018, and so on). SO3 may also be used as a fining agent. In embodiments, the glass composition further includes one or more or all of Fe2C>3, TiCh, and CF, which may be present in the glass composition as tramp (unintentional) constituents.

[0088] The glass substrate 10 further includes a first primary surface 12, a second primary surface 14, and a thickness 16 therebetween. The first primary surface 12 and the second primary surface 14 can face in generally opposite directions 18, 20. The thickness 16 is theshortest straight-line distance between the first primary surface 12 and the second primary surface 14. In embodiments, the thickness 16 is within a range of from 0.5 mm to 1.0 mm. The thickness 16 can be 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, or 1.0 mm, or within any range bound by any two of those values (e.g., from 0.6 mm to 0.9 mm, from 0.5 to 0.7 mm, and so on). The thickness 16 can be greater than 1.0 mm or less than 0.5 mm.

[0089] In addition to the thickness 16, the glass substrate 10 further includes a width 22 and a length 24. The width 22 and the length 24 are measured orthogonally to each other. In embodiments, the width 22 is greater than 90 cm while the length 24 is greater than 100 cm.As further discussed below, the collection of properties that the glass substrate 10 exhibits allows the glass substrate 10 to be made with the thickness 16 being relatively thin and the width 22 and the length 24 being relatively long.

[0090] The glass substrate 10 exhibits a density of less than 2.60 g / cm3. In embodiments, the density that the glass substrate 10 exhibits is less than 2.55 g / cm3. In embodiments, the density that the glass substrate 10 exhibits is less than 2.50 g / cm3. In embodiments, the density that the glass substrate 10 exhibits is less than 2.45 g / cm3. In embodiments, the density that the glass substrate 10 exhibits is less than 2.40 g / cm3. In embodiments, the density that the glass substrate 10 exhibits is 2.37 g / cm3, 2.38 g / cm3, 2.39 g / cm3, 2.40 g / cm3, 2.41 g / cm3, 2.42 g / cm3, 2.43 g / cm3, 2.44 g / cm3, 2.45 g / cm3, 2.46 g / cm3, 2.47 g / cm3, 2.48 g / cm3, 2.49 g / cm3, 2.50 g / cm3, 2.51 g / cm3, 2.52 g / cm3, 2.53 g / cm3, 2.54 g / cm3, 2.55 g / cm3, 2.56 g / cm3, 2.57 g / cm3, 2.58 g / cm3, 2.59 g / cm3, or 2.60 g / cm3, or within any range bound by any two of those values (e.g., from 2.37 g / cm3to 2.56 g / cm3, from 2.40 g / cm3to 2.50 g / cm3, and so on). The density values recited in this disclosure refer to a value as measured by the buoyancy method of ASTM C693-93 (2013).

[0091] The glass substrate 10 exhibits a coefficient of thermal expansion at 150 °C that is within a range of from 4.8 ppm / °C to 7.6 ppm / °C. In embodiments, the coefficient of thermal expansion that the glass substrate 10 exhibits is 4.8 ppm / °C, 4.9 ppm / °C, 5.0 ppm / °C, 5.1 ppm / °C, 5.2 ppm / °C, 5.3 ppm / °C, 5.4 ppm / °C, 5.5 ppm / °C, 5.6 ppm / °C, 5.7 ppm / °C, 5.8 ppm / °C, 5.9 ppm / °C, 6.0 ppm / °C, 6.1 ppm / °C, 6.2 ppm / °C, 6.3 ppm / °C, 6.4 ppm / °C, 6.5 ppm / °C, 6.6 ppm / °C, 6.7 ppm / °C, 6.8 ppm / °C, 6.9 ppm / °C, 7.0 ppm / °C, 7.1 ppm / °C, 7.2 ppm / °C, 7.3 ppm / °C, 7.4 ppm / °C, 7.5 ppm / °C, or 7.6 ppm / °C, or within any range bound by any two of those values (e.g., from 5.5 ppm / °C to 6.8 ppm / °C, from 5.5 ppm / °C to 7.0 ppm / °C, from 6.0 ppm / °C to 7.0 ppm / °C, from 6.0 ppm / °C to 6.5 ppm / °C, and so on). The coefficient of thermal expansion is the amount of dimensional change as a function oftemperature, and here throughout, a temperature range (e.g., °C), (such as from room temperature to 300 °C) that includes 150 °C. The value at issue is the instantaneous value at 150 °C. The coefficient of thermal expansion is determined following ASTM standard E228.

[0092] The glass substrate 10 exhibits a liquidus viscosity that is greater than 40,000 Poise. In embodiments, the liquidus viscosity that the glass substrate 10 exhibits is greater than 50,000 Poise, greater than 150,000 Poise, greater than 250,000 Poise, or greater than 400,000 Poise. In embodiments, the liquidus viscosity that the glass substrate 10 exhibits is within a range of from 40,000 Poise to 1,500,000 Poise. In embodiments, the liquidus viscosity that the glass substrate 10 exhibits is within a range of from 40 kP (kP meaning kilopoise), 50 kP, 100 kP, 200 kP, 300 kP, 400 kP, 500 kP, 600 kP, 700 kP, 800 kP, 900 kP, 1000 kP, 1100 kP, 1200 kP, 1300 kP, 1400 kP, or 1500 kP, or within any range bound by any two of those values (e.g., from 200 kP to 900 kP, from 600 kP to 1400 kP, and so on). The liquidus temperature of the glass substrate 10 is the temperature where the first crystal is observed in a standard gradient boat liquidus measurement conducted pursuant to ASTM C829-81. The liquidus viscosity is the viscosity of the molten glass substrate 10 corresponding to the liquidus temperature.

[0093] The glass substrate 10 exhibits a viscosity at 200 Poise at a temperature of less than 1725 °C. In embodiments, the temperature at which the glass substrate 10 exhibits a viscosity of 200 Poise is less than 1705 °C, less than 1700 °C, less than 1650 °C, less than 1630 °C, less than 1600 °C, or less than 1550 °C. In embodiments, the temperature at which the glass substrate 10 exhibits a viscosity of 200 Poise is 1510 °C, 1515 °C, 1520 °C, 1530 °C, 1540 °C, 1550 °C, 1560 °C, 1570 °C, 1580 °C, 1590 °C, 1600 °C, 1610 °C, 1620 °C, 1630 °C, 1640 °C, 1650 °C, 1660 °C, 1670 °C, 1680 °C, 1690 °C, 1700 °C, 1705 °C, 1710 °C, 1720 °C, or 1725 °C, or within any range bound by any two of those values (e.g., from 1510 °C to 1725 °C, from 1520 °C to 1630 °C, and so on). The temperature at which the glass substrate 10 exhibits a viscosity of 200 Poise is measured by concentric cylinder viscometry.

[0094] Referring additionally to FIGS. 3-4, an insulated glass unit 100 is herein described. The insulated glass unit 100 includes a first pane 102 and a second pane 104, which are disposed substantially parallel to each other. A space 106 separates the first pane 102 from the second pane 104. The insulated glass unit 100 can include a spacer 108 between the first pane 102 and the second pane 104 to further define the space 106 and help establish a distance 110 between the first pane 102 and the second pane 104. The distance 110 can beany value, but can be from 50 pm to 50 mm, such as from 5 mm to 25 mm. The spacer 108 may be an edge seal formed around respective edges of the first pane 102 and the second pane 104, a metallic pillar between the surfaces of the first pane 102 and the second pane 104, a low thermal conduction material, or a glass bump attached to or formed integral with one or both of the first pane 102 and the second pane 104. The insulated glass unit 100 can further include a frame 112 around the edges of the first pane 102 and the second pane 104. The space 106 may be sealed and include an insulating gas such as air, argon, krypton, xenon, and combinations thereof. The space 106 may be sealed and include a pressure less than atmospheric pressure. The first pane 102 can be considered to be the outside glass pane (e.g., intended to face an exterior environment during use). The second pane 104 can be considered to be the inside glass pane (e.g., intended to face an interior environment during use). The insulated glass unit 100 may be part of a window or a door, among other options. Although the insulated glass unit 100 is illustrated and described herein as a double pane structure, the insulated glass unit 100 can be a triple pane structure or any number of panes.

[0095] The first pane 102 includes a body 114 with an outside surface 116 opposite an inside surface 118. In embodiments, the outside surface 116 is directly exposed to an external environment 120 (e.g., outside). In embodiments, the inside surface 118 is adjacent the space 106 between the first pane 102 and the second pane 104. In embodiments, the first pane 102 additionally includes at least one outer edge 122. In embodiments, the first pane 102 may include additional surfaces and / or edges.

[0096] In embodiments, the first pane 102 is formed from a glass material. Example glass materials include soda lime glass, aluminosilicate glass, and borosilicate glass, among other options. In embodiments, the first pane 102 further includes a low emissivity layer 124. The low emissivity layer 124 may be on the inside surface 118, such that low emissivity layer 124 is shielded from weather and other outdoor elements. Yet in alternative embodiments, the first pane 102 may be entirely comprised of a low emissivity composition, in which case the low emissivity layer 124 would occupy entirely the body 114 of the first pane 102. Absorption and / or reflection of infrared and near infrared wavelengths from the external environment 120 by the low emissivity layer 124 minimizes heat transfer into the space 106, onto the second pane 104, and / or across the insulated glass unit 100 into an interior 126 such as of an enclosure or building.

[0097] For purposes of this disclosure, the second pane 104 is a laminate that includes a first glass layer 128, the glass substrate 10 as a second glass layer 130, and an interlayer 132disposed between the first glass layer 128 and the second glass layer 130. The first glass layer 128 is or includes soda lime glass. The interlayer 132 can assist with bonding the first glass layer 128 and the second glass layer 130 (the glass substrate 10) together. Examples of the interlayer 132 include polyvinyl butyral (PVB), polycarbonate, acoustic PVB, ethylene vinyl acetate (EVA), thermoplastic polyurethane (TPU), an ionomer, a thermoplastic material, and / or combinations thereof.

[0098] The first glass layer 128 provides an outside surface 134 of the second pane 104. The outside surface 134 is adjacent space 106 between the first pane 102 and the second pane 104. The second primary surface 14 of the glass substrate 10 as the second glass layer 130 provides an inside surface 136 of the second pane 104. In embodiments, the inside surface 136 is directly exposed to the interior 126. In embodiments, the second pane 104 also includes at least an outer edge 138. In embodiments, the second pane 104 may include additional surfaces and / or edges.

[0099] The first pane 102 has a thickness 140 between the inside surface 118 and the outside surface 116. In embodiments, the thickness 140 is within a range of from 2.0 mm to 8.0 mm, such as about 5 mm. The thickness 140 being thinner or thicker than those values is envisioned.

[0100] The first glass layer 128 of the second pane 104 likewise has a thickness 142. The thickness 142 of the first glass layer 128 is from the outside surface 134 to a surface 144 facing the interlayer 132. In embodiments, the thickness 142 of the first glass layer 128 is within a range of from 2.0 mm to 8.0 mm, such as about 5 mm. The thickness 142 being thinner or thicker than those values is envisioned. In embodiments, as mentioned, the thickness 16 of the second glass layer 130 of the second pane 104 (as an example use of the glass substrate 10 of the present disclosure) is within a range of from 0.5 mm to 1.0 mm. The thickness 16 being thinner or thicker than those values is envisioned, as well.

[0101] Each of the first pane 102, the first glass layer 128 of the second pane 104, and the second glass layer 130 of the second pane 104 (as an example use of the glass substrate 10 of the present disclosure) can have widths 22 and lengths 24 that are within a range of from 0.1 m to 10 m, such as greater than 90 cm (0.9 m) or greater than 100 cm (1.0 m). Wider, narrower, shorter, and longer values are envisioned.

[0102] Referring now to FIGS. 5-7, a method 200 of manufacturing the glass substrate 10 and subsequently the second glass layer 130 is herein described. At a fusion forming step 202, the method 200 includes causing the glass composition of the present disclosure to flowin a molten state into a trough 204 of an isopipe 206. The glass composition in the molten state then overflows the trough 204 and flows over outer forming surface 208 of the isopipe 206 to converge at a root 210 and to form a glass ribbon 212. As mentioned, embodiments of the glass composition described herein, while in the molten state, exhibit a temperature of less than 1705 °C and a viscosity of greater than 50,000, which make those embodiments compatible with the fusion forming step 202.

[0103] At a separating step 214, the method 200 further includes separating the glass substrate 10 from the glass ribbon 212. As the glass ribbon 212 moves downward from the root 210, the glass ribbon 212 cools and solidifies. A scoring device 216 with a scoring member 218 (e.g., a score wheel, a scribe, a laser, among other options) is extended in a direction toward the glass ribbon 212 so that scoring member 218 comes into contact with a first primary surface 12’ or a second primary surface 14’ of the glass ribbon 212. The scoring device 216 is then traversed laterally across the glass ribbon 212, thereby forming a score line 220 across at least a portion of the total width 22 of glass ribbon 212. When the score line 220 has been completed, the scoring device 216 and / or the scoring member 218 disengages from the glass ribbon 212 and the scoring device 216 and / or scoring member 218 is retracted in a direction away from the glass ribbon 212.

[0104] A bend can then be produced in the glass ribbon 212 that induces a tensile stress across the score line 220. That is, whichever of the first primary surface 12’ or the second primary surface 14’ of the glass ribbon 212 that includes the score line 220 is placed in tension across the score line 220, while the other of the first primary surface 12’ and the second primary surface 14’ is placed in compression. The tensile stress in turn drives a crack from the score line 220 through the thickness of the glass ribbon 212, thereby completely separating the glass substrate 10 (as a glass sheet) from the glass ribbon 212. During the scoring, the glass ribbon 212 at the location of the score line 220 may have a temperature in the range from about 350 °C to about 500 °C.

[0105] In embodiments, the method 200 further includes a laminating step 222. The laminating step 222 includes laminating the glass substrate 10 to a glass layer (e.g., the first glass layer 128) comprising soda lime glass at a lamination temperature within a range of from 100 °C to 200 °C and thereby forming a glass pane (e.g., the second pane 104). To laminate, the glass substrate 10 can be attached to the first glass layer 128 with the interlayer 132 to produce a stack of those components. The stack thus produced can then be heated to the lamination temperature using any suitable method or apparatus known in the art. By wayof a non-limiting example, the stack can be placed in a vacuum chamber, such as in a vacuum or lamination bag. The stack may be wrapped or otherwise secured to prevent shifting of the stack. For example, the stack may be secured using high-temperature tape, such as polyester tape. A thin breather cloth can be wrapped around the stack according to various embodiments.

[0106] The stack(s) may be processed one at a time, in a single layer within the chamber, or in multiple layers of stacks, depending on the desired throughput. The lamination bag can be heat sealed and a vacuum port can be attached thereto. The vacuum chamber can be at least partially evacuated, and the stack(s) can be heated using a predetermined temperature and pressure profile. In some instances, the stack(s) can be placed between two plates which can be used to apply pressure to the stack and / or heat and / or cool the respective layers of the stack. For example, the laminating step 222 may be conducted with specific temperature and pressure profiles used to achieve desired adhesion (bonding) quality of the laminated structure. Of course, other apparatuses and methods for achieving the lamination temperature and / or pressure can be used and are envisioned as falling within the scope of the disclosure.

[0107] The laminating step 222 can comprise ramping to the lamination temperature at a ramp rate ranging from 1 °C / min to 10 °C / min, such as from 2 °C / min to 9 °C / min, from 3 °C / min to 8 °C / min, from 4 °C / min to 7 °C / min, or from 5 °C / min to 6 °C / min. According to additional embodiments, the lamination pressure can range from about 0.1 MPa to about 1.5 MPa, such as from about 0.2 MPa to about 1.4 MPa, from about 0.3 MPa to about 1.3 MPa, from about 0.4 MPa to about 1.2 MPa, from about 0.5 MPa to about 1.1 MPa, from about 0.6 MPa to about 1 MPa, or from about 0.8 MPa to about 0.9 MPa, including all ranges and subranges therebetween. Pressure, if applied, may be applied gradually during temperature ramping or upon reaching the lamination temperature. Pressure may be gradually applied, e.g., at a ramp rate ranging from 20 Pa / min to 100 Pa / min, such as from 30 Pa / min to 80 Pa / min, from 40 Pa / min to 70 Pa / min, or from 50 Pa / min to 60 Pa / min, including all ranges and subranges therebetween. In embodiments, the stack may be held at the lamination temperature and pressure for a residence time ranging from 10 minutes to 120 minutes, such as from 20 minutes to 100 minutes, from 30 minutes to 80 minutes, or from 40 minutes to 60 minutes, including all ranges and subranges therebetween.

[0108] After the desired residence time, the temperature can be ramped down, e.g., to room temperature at a rate ranging from 1 °C / min to 10 °C / min, such as from about 2 °C / min to about 9 °C / min, from 3 °C / min to 8 °C / min, from 4 °C / min to 7 °C / min, or from 5 °C / min to6 °C / min, including all ranges and subranges therebetween. According to various embodiments, the temperature can be ramped down while maintaining the lamination pressure which can, in certain embodiments, reduce the formation of bubbles in the interlayer 132. Alternatively, the pressure can be reduced before or during temperature ramping. A gradual pressure reduction can be used, in some embodiments, for instance, at a ramp rate ranging from 20 Pa / min to 100 Pa / min, such as from 30 Pa / min to 80 Pa / min, from 40 Pa / min to 70 Pa / min, or from 50 Pa / min to 60 Pa / min, including all ranges and subranges therebetween.

[0109] In embodiments, the method 200 further includes a recycling step 224. The recycling step 224 includes recycling the glass pane (e.g., the second pane 104) with soda lime glass and the glass substrate 10 with the glass composition of the present disclosure to form recycled glass material.

[0110] The glass substrate 10 with the glass composition of the present disclosure, the insulated glass unit 100 incorporating the glass substrate 10, and the method 200 described herein address the problem set forth in the Background, in a variety of ways. First, the glass composition lacks B2O3. Thus, the glass substrate 10, and the second pane 104 with the first glass layer 128 of soda lime glass and the glass substrate 10 (as the second glass layer 130) can be recycled together with other soda lime glasses. Second, studies have shown when the first glass layer 128 of a glass pane laminate (e.g., the second pane 104) is soda lime glass and has a thickness 142 of 3 mm and the second glass layer 130 of the glass pane laminate has a thickness 16 of 0.7 mm, the coefficient of thermal expansion of the second glass layer 130 should be about 6.5 ppm / °C to generate no bow upon cooling. As mentioned, the glass substrate 10 with the glass composition of the present disclosure exhibits a coefficient of thermal expansion within a range approximately centered around that value. Thus, incorporation of the glass substrate 10 into a laminate with soda lime glass of a greater thickness 16 generates little to no bow upon cooling (from the laminate temperature). Third, the glass composition of the glass substrate 10 of the present disclosure exhibits a liquidus viscosity and a temperature at a viscosity of 200 Poise that permits the glass substrate 10 to be formed via the fusion forming step 202, which can generate thin, wide, and long sheets suitable for integration within modern insulated glass units 100. This combination of a relatively low temperature at a viscosity of 200 Poise yet a relatively high liquidus viscosity is challenging to obtain, but the glass composition of the present disclosure does. Consequently, the thin glass substrate 10 can be used as a laminate with the thicker soda limeglass, instead of another layer of thick soda lime glass, and thereby makes more efficient use of resources and reduces the overall weight of the laminate and insulated glass unit 100. Relatedly, the glass substrate 10 itself has a relatively low density, which reduces shipping costs and product weight.

[0111] EXAMPLES

[0112] Examples 1-26 - The glass substrates of Examples 1-26 were batched and fusion formed. The mole percentages of the identified constituents were determined via X-ray fluorescence. Various properties were measured via the methods described above. The measured values for the mole percentages of the glass compositions and for the properties that the glass substrates exhibit are set forth in Table 1 below. Examples 1-26 exhibit all of the following properties: (i) a coefficient of thermal expansion at 150 °C that is within a range of from 6.0 ppm / °C to 7.0 ppm / °C, (ii) a liquidus viscosity that is greater than 150,000 Poise, (iii) a viscosity of 200 Poise at a temperature of less than 1705 °C, and (iv) a density that is less than 2.55 g / cm3.

[0113] Examples 27-48 - The glass substrates of Examples 27-48 were also batched and fusion formed. The mole percentages of the identified constituents were determined via X- ray fluorescence. Various properties were measured via the methods described above. The measured values for the mole percentages of the glass compositions and for the properties that the glass substrates exhibit are set forth in Table 2 below. Examples 27-48 are all examples of embodiments of the glass substrate of the present disclosure that exhibit a density that is less than 2.55 g / cm3. However, Examples 29-31, 36, and 48 can be comparative examples regarding the coefficient of thermal expansion at 150 °C as falling outside of the range of from 6.0 ppm / °C to 7.0 ppm / °C, while all of Examples 1-26 exhibit a coefficient of thermal expansion within that range. Similarly, Examples 27-38 and 48 can be comparative examples regarding liquidus viscosity, as they all exhibit a liquid viscosity that is less than 150,000 Poise. Finally, Examples 30, 31, and 33 can be comparative examples as exhibiting a viscosity of 200 Poise at a temperature of greater than 1705 °C.

[0114] Modifications of the disclosure will occur to those skilled in the art and to those who make or use the disclosure. Therefore, it is understood that the embodiments shown in the drawings and described above are merely for illustrative purposes and not intended tolimit the scope of the disclosure, which is defined by the following claims, as interpreted according to the principles of patent law, including the doctrine of equivalents.

[0115] Directional terms as used herein — for example up, down, right, left, front, back, top, bottom — are made only with reference to the figures as drawn and are not intended to imply absolute orientation. Similarly, in this document, relational terms, such as first and second, top and bottom, and the like, are used solely to distinguish one entity or action from another entity or action, without necessarily requiring or implying any actual such relationship or order between such entities or actions.

[0116] While exemplary embodiments and examples have been set forth for the purpose of illustration, the foregoing description is not intended in any way to limit the scope of disclosure and appended claims. Accordingly, variations and modifications may be made to the above-described embodiments and examples 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.

Claims

CLAIM(S)What is claimed is:

1. A glass substrate comprising: a glass composition comprising (on an oxide basis and in mole percentage):SiCh, within a range of from 74.0 to 78.0;AI2O3, within a range of from 3.00 to 5.70;R2O, within a range of from 7.00 to 11.30; andR’O, within a range of from 5.70 to 13.90; wherein, R2O is the sum of Na2O and K2O, with Na2O being within a range of from 7.10 to 11.25 and K2O being within a range of from 0.005 to 6.7; wherein, R’O is the sum of MgO, CaO, SrO, and BaO, with MgO being within a range of from 2.50 to 8.30, CaO being within a range of from 0.01 to 4.20, SrO being within a range of from 0 to 5.20, and BaO being within a range of from 0 to 0.10; wherein, R2O + CaO + SrO + BaO + ZnO - AI2O3 is within a range of from 8.70 to 11.64; and wherein, the glass composition is substantially free of B2O3.

2. The glass substrate of claim 1, wherein in the glass composition, MgO / (R’O + ZnO) is within a range of from 0.350 to 0.700.

3. The glass substrate of any one of claims 1-2, wherein in the glass composition, R2O - AI2O3 - MgO - CaO is within a range of from -4.25 to 0.

4. The glass substrate of any one of claims 1-3, wherein the glass composition further comprises SnO2, Fe2O3, TiO2, and Cl’.

5. The glass substrate of any one of claims 1-4 further comprising: a thickness within a range of from 0.5 mm to 1.0 mm.

6. The glass substrate of any one of claims 1-5 further comprising: a width that is greater than 90 cm; and a length that is greater than 100 cm.

7. The glass substrate of any one of claims 1-6, wherein the glass substrate exhibits a coefficient of thermal expansion at 150 °C that is within a range of from 6.0 ppm / °C to 7.0 ppm / °C.

8. The glass substrate of any one of claims 1-7, wherein the glass substrate exhibits a liquidus viscosity that is greater than 150,000 Poise.

9. The glass substrate of any one of claims 1-8, wherein the glass substrate exhibits a viscosity of 200 Poise at a temperature of less than 1705 °C.

10. The glass substrate of any one of claims 1-9, wherein the glass substrate exhibits a density of less than 2.55 g / cm3.

11. A glass substrate comprising: a glass composition comprising (on an oxide basis, and in mole percentage):SiCh, within a range of from 72.0 to 78.5;AI2O3, within a range of from 1.70 to 9.20;R2O, within a range of from 5.30 to 11.60; andR’O, within a range of from 5.70 to 13.90; wherein, R2O is the sum of Na2O and K2O, with Na2O being within a range of from 2.80 to 11.60 and K2O being within a range of from 0.005 to 6.70; wherein, R’O is the sum of MgO, CaO, SrO, and BaO, with MgO being within a range of from 0.40 to 8.30, CaO being within a range of from 0.01 to 8.50, SrO being within a range of from 0 to 6.50, and BaO being within a range of from 0 to 0.10; and wherein, the glass composition is substantially free of B2O3.

12. The glass substrate of claim 11, wherein in the glass composition, CaO / (R’O + ZnO) is within a range of from 0.004 to 0.620.

13. The glass substrate of any one of claims 11-12, wherein in the glass composition, SrO / (R’O + ZnO) is within a range of from 0 to 0.37.

14. The glass substrate of any one of claims 11-13, wherein in the glass composition, (R’O + ZnO) / AI2O3 is within a range of from 1.00 to 4.00.

15. The glass substrate of any one of claims 11-14, wherein in the glass composition, R’O + ZnO is within a range of from 5.70 to 14.00.

16. The glass substrate of any one of claims 11-15, wherein the glass composition further comprises SnO2, Fe2O3, TiO2, and Cl’.

17. The glass substrate of any one of claims 11-16, wherein in the glass composition, Na2O is within a range of from 7 to 11.6.

18. The glass substrate of any one of claims 11-17, wherein in the glass composition, K2O is within a range of from 0.005 to 4.00.

19. The glass substrate of any one of claims 11-18, wherein the glass substrate exhibits a density of less than 2.60 g / cm3.

20. The glass substrate of any one of claims 11-19, wherein in the glass composition, SrO is within a range of from 0 to 6.00, and the glass substrate exhibits a density of less than 2.55 g / cm3.

21. The glass substrate of any one of claims 11-20, wherein in the glass composition, R’O is within a range of from 5.70 to 13.30; in the glass composition, SrO is within a range of from 0 to 3.60, and the glass substrate exhibits a density of less than 2.50 g / cm3.

22. The glass substrate of any one of claims 11-21, wherein in the glass composition, CaO is within a range of from 2.50 to 8.20; in the glass composition, SrO is within a range of from 0 to 2.40, and the glass substrate exhibits a density of less than 2.45 g / cm3.

23. The glass substrate of any one of claims 11-22, wherein in the glass composition, SrO is within a range of from 0 to 1.20.

24. The glass substrate of any one of claims 11-23, wherein in the glass composition, AI2O3, is within a range of from 1.70 to 6.00.

25. The glass substrate of any one of claims 11-24, wherein the glass substrate exhibits a coefficient of thermal expansion at 150 °C that is within a range of from 4.8 ppm / °C to 7.6 ppm / °C.

26. The glass substrate of any one of claims 11-25, wherein in the glass composition, Na?O is within a range of from 7.10 to 11.25, and the glass substrate exhibits a coefficient of thermal expansion at 150 °C that is within a range of from 6.0 ppm / °C to 7.0 ppm / °C.

27. The glass substrate of any one of claims 25, wherein in the glass composition, R2O - AI2O3 - MgO - CaO is within a range of from -4.30 to 0, and the glass substrate exhibits a coefficient of thermal expansion at 150 °C that is within a range of from 6.0 ppm / °C to 7.0 ppm / °C.

28. The glass substrate of any one of claims 11-27, wherein in the glass composition, Na2O is within a range of from 7.20 to 9.90, and the glass substrate exhibits a coefficient of thermal expansion at 150 °C that is within a range of from 6.0 ppm / °C to 6.5 ppm / °C.

29. The glass substrate of any one of claims 11-28, wherein the glass substrate exhibits a liquidus viscosity that is greater than 50,000 Poise.

30. The glass substrate of any one of claims 11-28, wherein the glass substrate exhibits a liquidus viscosity that is greater than 150,000 Poise.

31. The glass substrate of any one of claims 11-28, wherein the glass substrate exhibits a liquidus viscosity that is greater than 250,000 Poise.

32. The glass substrate of any one of claims 11-31, wherein the glass substrate exhibits a viscosity of 200 Poise at a temperature of less than 1725 °C.

33. The glass substrate of any one of claims 11-31, wherein the glass substrate exhibits a viscosity of 200 Poise at a temperature of less than 1650 °C.

34. The glass substrate of any one of claims 11-31, wherein the glass substrate exhibits a viscosity of 200 Poise at a temperature of less than 1630 °C.

35. The glass substrate of any one of claims 11-34 further comprising: a thickness within a range of from 0.5 mm to 1.0 mm.

36. The glass substrate of any one of claims 11-35 further comprising: a width that is greater than 90 cm; and a length that is greater than 100 cm.

37. A glass substrate comprising: a glass composition comprising (on an oxide basis, and in mole percentage):SiCh, within a range of from 70.0 to 80.0;AI2O3, within a range of from 1.60; to 9.20;Na2O, within a range of from 2.80 to 12.50;MgO, within a range of from 0 to 10.00;CaO, within a range of from 0 to 8.50;SrO, within a range of from 0 to 8.00;ZnO, within a range of from 0 to 2.00;K2O, within a range of from 0 to 6.70; andSnCh, within a range of from 0 to 0.20; wherein, the glass substrate exhibits a coefficient of thermal expansion at 150 °C that is within a range of from 5.5 ppm / °C to 7.0 ppm / °C, wherein, the glass substrate exhibits a density of less than 2.60 g / cm3, wherein, the glass substrate exhibits a viscosity of 200 Poise at a temperature of less than 1700 °C, wherein, the glass substrate exhibits a liquidus viscosity that is greater than 150,000 Poise, and wherein, the glass composition is substantially free of B2O3.

38. The glass substrate of claim 37, wherein the glass substrate exhibits a coefficient of thermal expansion at 150 °C that is within a range of from 5.5 ppm / °C to 6.8 ppm / °C, the glass substrate exhibits a density of less than 2.50 g / cm3, and the glass substrate exhibits a viscosity of 200 Poise at a temperature of less than 1650 °C, and wherein, the glass substrate exhibits a liquidus viscosity that is greater than 250,000 Poise.

39. The glass substrate of claim 37, wherein in the glass composition, SiCh is within a range of from 73.0 to 78.0, in the glass composition, AI2O3 is within a range of from 3.00 to 6.00, in the glass composition, Na2O is within a range of from 8.00 to 11.50, in the glass composition, MgO is within a range of from 2.00 to 8.50, in the glass composition, CaO is within a range of from 0 to 4.50, in the glass composition, SrO is within a range of from 0 to 5.00, in the glass composition, ZnO is within a range of from 0 to 1.00, in the glass composition, K2O is within a range of from 0 to 2.00, in the glass composition, SnO2 is within a range of from 0 to 0.10,the glass substrate exhibits a coefficient of thermal expansion at 150 °C that is within a range of from 5.5 ppm / °C to 6.8 ppm / °C, the glass substrate exhibits a density of less than 2.50 g / cm3, and the glass substrate exhibits a viscosity of 200 Poise at a temperature of less than 1630 °C, and wherein, the glass substrate exhibits a liquidus viscosity that is greater than 250,000 Poise.

40. The glass substrate of claim 39, wherein the glass substrate exhibits a liquidus viscosity that is greater than 400,000 Poise.

41. An insulating glass unit comprising: a first pane; and a second pane separated from the first pane by a space, the second pane comprising a laminate comprising a first glass layer and a second glass layer, the first glass layer comprising soda lime glass and the second glass layer comprising a glass composition comprising (on an oxide basis and in mole percentage):SiCh, within a range of from 70.0 to 80.0;AI2O3, within a range of from 1.60; to 9.20;Na2O, within a range of from 2.80 to 12.50;MgO, within a range of from 0 to 10.00;CaO, within a range of from 0 to 8.50;SrO, within a range of from 0 to 8.00;ZnO, within a range of from 0 to 2.00;K2O, within a range of from 0 to 6.70; andSnCh, within a range of from 0 to 0.20; wherein, the glass composition is substantially free of B2O3.

42. The insulated glass unit of claim 41, wherein the glass composition of the second glass layer of the second pane comprises:SiCh, within a range of from 72.0 to 78.5;AI2O3, within a range of from 1.70 to 9.20;R2O, within a range of from 5.30 to 11.60; andR’O, within a range of from 5.70 to 13.90; wherein, R2O is the sum of Na?O and K2O, with Na2O being within a range of from 2.80 to 11.60 and K2O being within a range of from 0.005 to 6.70; and wherein, R’O is the sum of MgO, CaO, SrO, and BaO, with MgO being within a range of from 0.40 to 8.30, CaO being within a range of from 0.01 to 8.50, SrO being within a range of from 0 to 6.50, and BaO being within a range of from 0 to 0.10.

43. The insulated glass unit of claim 42, wherein in the glass composition of the second glass layer, SiO2 is within a range of from 74.0 to 78.0; AI2O3 is within a range of from 3.00 to 5.70; R2O is within a range of from 7.00 to 11.30; R’O is within a range of from 5.70 to 13.90; Na2O is within a range of from 7.1 to 11.25; MgO is within a range of from 2.50 to 8.30; CaO is within a range of from 0.01 to 4.20; SrO is within a range of from 0 to 5.20; and R2O + CaO + SrO + BaO + ZnO - AI2O3 is within a range of from 8.70 to 11.64.

44. The insulated glass unit of any one of claims 41-43, wherein the first pane comprises soda lime glass.

45. The insulated glass unit of any one of claims 41-44, wherein the first glass layer of the second pane comprises a thickness within a range of from 2.0 mm to 8.0 mm, and the first pane comprises a thickness within a range of from 2.0 mm to 8.0 mm.

46. The insulated glass unit of any one of claims 41-45, wherein the second glass layer of the second pane comprises a thickness within a range of from 0.5 mm to 1.0 mm.

47. The insulated glass unit of any one of claims 41-46, wherein the second glass layer of the second pane comprises: a width that is greater than 90 cm; and a length that is greater than 100 cm.

48. The insulated glass unit of any one of claims 41-47, wherein the second glass layer of the second pane exhibits a coefficient of thermal expansion at 150 °C that is within a range of from 6.0 ppm / °C to 7.0 ppm / °C.

49. The insulated glass unit of any one of claims 41-48, wherein the second glass layer of the second pane exhibits a liquidus viscosity that is greater than 150,000 Poise.

50. The insulated glass unit of any one of claims 41-49, wherein the second glass layer of the second pane exhibits a viscosity of 200 Poise at a temperature of less than 1725 °C.

51. The insulated glass unit of any one of claims 41-50, wherein the second glass layer of the second pane exhibits a density of less than 2.55 g / cm3.

52. A method of manufacturing a glass substrate comprising: a fusion forming step comprising causing a glass composition to flow in a molten state into a trough of an isopipe, overflow the through, and then flow over outer forming surfaces of the isopipe to converge at a root and form a glass ribbon; and a separating step comprising separating a glass substrate from the glass ribbon, wherein, the glass composition in the molten state comprises a temperature of less than 1705 °C, wherein, the glass composition in the molten state exhibits a viscosity that is greater than 50,000 Poise, and wherein, the glass composition comprises (on an oxide basis and in mole percentage):SiCh, within a range of from 70.0 to 80.0;AI2O3, within a range of from 1.60; to 9.20;Na2O, within a range of from 2.80 to 12.50;MgO, within a range of from 0 to 10.00;CaO, within a range of from 0 to 8.50;SrO, within a range of from 0 to 8.00;ZnO, within a range of from 0 to 2.00;K2O, within a range of from 0 to 6.70; andSnCh, within a range of from 0 to 0.20; wherein, the glass composition is substantially free of B2O3.

53. The method of claim 52, wherein the glass composition comprises (on an oxide basis and in mole percentage):SiCh, within a range of from 72.0 to 78.5;AI2O3, within a range of from 1.70 to 9.20;R2O, within a range of from 5.30 to 11.60; andR’O, within a range of from 5.70 to 13.90; wherein, R2O is the sum of Na2O and K2O, with Na2O being within a range of from 2.80 to 11.60 and K2O being within a range of from 0.005 to 6.7; and wherein, R’O is the sum of MgO, CaO, SrO, and BaO, with MgO being within a range of from 0.40 to 8.30, CaO being within a range of from 0.01 to 8.50, SrO being within a range of from 0 to 6.50, and BaO being within a range of from 0 to 0.10.

54. The method of claim 53, wherein the glass composition comprises (on an oxide basis and in mole percentage):SiO2, within a range of from 74.0 to 78.0;AI2O3, within a range of from 3.00 to 5.70;R2O, within a range of from 7.00 to 11.30; andR’O, within a range of from 5.70 to 13.90; wherein, R2O is the sum of Na2O and K2O, within Na2O being within a range of from 7.1 to 11.25 and K2O being greater than or equal to 0.005; wherein, R’O is the sum of MgO, CaO, SrO, and BaO, with MgO being within a range of from 2.50 to 8.30, CaO being within a range of from 0.01 to 4.20, SrO being within a range of from 0 to 5.20, and BaO being within a range of from 0 to 0.10; andwherein, R2O + CaO + SrO + BaO + ZnO - AI2O3 is within a range of from 8.70 to 11.64.

55. The method of any one of claims 52-54 further comprising: a laminating step comprising laminating the glass substrate to a glass layer comprising soda lime glass at a lamination temperature within a range of from 100 °C to 200 °C and thereby forming a glass pane; wherein, the glass substrate exhibits a coefficient of thermal expansion at 150 °C that is within a range of from 6.0 ppm / °C to 7.0 ppm / °C, and wherein, the glass substrate exhibits a density of less than 2.55 g / cm3.

56. The method of any one of claims 52-55 further comprising: a recycling step comprising recycling the glass pane with soda lime glass to form recycled glass material.

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