Tempered glass-based article

Abstract

The present invention relates to a method of manufacturing a strengthened glass-based article comprising at least partially compressing a coating layer bonded to the glass by tightening the glass from a first density to a second density that is at least 10 mg / cm3 greater than the first density, the tightening occurs when the glass is heated to a temperature above 100 DEG C and below the softening temperature of the glass, whereby the tightened glass compresses the coating, thereby strengthening the glass-based article.

Description

[0001] Cross - reference to related applications

[0002] This application claims priority to U.S. Provisional Application No. 63 / 431,490, filed on December 09, 2022, the content of which is incorporated herein by reference in its entirety. Background Art

[0003] Aspects of the present disclosure generally relate to glass - based articles, such as glass sheets, laminates including glass layers, and glass containers. More specifically, the present disclosure relates to strengthened glass - based articles, where the glass portion of the article compresses a cladding or a portion of the cladding of the article.

[0004] Glass articles can be strengthened in various ways, such as by thermal tempering, chemical tempering (so - called "ion exchange"), and by taking advantage of, for example, differences in the thermal expansion characteristics of different glasses in a glass - to - glass laminate. Each strengthening process has its uses and drawbacks in specific situations. For example, thermal tempering may be useful for thick glass sheets, but may be difficult to achieve for thinner wafers. Chemical tempering can be time - consuming and resource - intensive and may be limited to certain glass compositions, such as those that can facilitate ion exchange in a salt bath. Glasses in a glass - to - glass laminate can be selected such that a first piece of glass expands more at the melting temperature than a second piece of glass, in which case when the glass cools, the first piece of glass shrinks more than the second piece of glass and subjects the second piece of glass to compression. Such a glass - to - glass laminate may be difficult to process due to internal stress when cooled, where the rupture of the first piece of glass (in a tensile state) can be catastrophic.

[0005] There is a need for another method of strengthening glass - based articles to overcome some or all of the above challenges. Summary of the Invention

[0006] The applicant has discovered a new method of strengthening glass - based articles. The technique can be implemented after the manufacture, handling, and processing of the article so that this treatment can be performed when the article is in a lower stress state. Additionally, the technique can be implemented in a controlled manner to fine - tune the magnitude of the stress applied to the glass - based article. The fine - tuning can bring the compressive stress of the article's cladding just below the brittle limit.

[0007] According to aspect A1, a method of manufacturing a strengthened glass - based article includes at least partially compressing a cladding adhered to the glass by tightening the glass from a first density to a second density that is at least 10 mg / cm 3 greater than the first density. The tightening occurs when the glass is heated to a temperature above 100 °C and below the softening temperature of the glass, whereby the tightened glass compresses the cladding, thereby strengthening the glass - based article.

[0008] According to aspect A2, aspect A1 further includes cutting the glass-based article before tightening.

[0009] According to aspect A3, aspect A1 further includes polishing at least a portion of the glass-based article before tightening.

[0010] According to aspect A4, the temperature of aspect A1 is higher than 200 °C.

[0011] According to aspect A5, the tightening of aspect A4 further includes maintaining the glass generally at or above the temperature for at least one hour.

[0012] According to aspect A6, before heating in aspect A4, the temperature of the glass is lower than 50 °C.

[0013] According to aspect A7, the glass of aspect A1 is a first glass portion, and wherein the cladding is a second glass portion.

[0014] According to aspect A8, the first glass portion and the second glass portion of aspect A7 have different compositions, and the glass of the first glass portion contains at least 5 mol% less SiO2 than the glass of the second glass portion.

[0015] According to aspect A9, the glass of the first glass portion of aspect A8 contains more B2O3 than the glass of the second glass portion.

[0016] According to aspect A10, the second glass portion of aspect A7 is directly fused to the first glass portion.

[0017] According to aspect A11, the first glass portion of aspect A10 is located inside the second glass portion such that the second glass portion covers at least two opposite faces of the first glass portion.

[0018] According to aspect A12, the fictive temperature of the glass of the first glass portion of aspect A7 is lower than that of the glass of the second glass portion.

[0019] According to aspect B1, a method of manufacturing a strengthened glass-based article includes: rapidly cooling molten glass; bonding the glass to a cladding; while bonded to the cladding, heating the glass to a temperature above 100 °C and below the softening temperature of the glass to increase the density of the glass by at least 10 mg / cm 3 ; and during the heating, by tightening the glass bonded to the cladding, applying a compressive stress to the cladding so as to compress the cladding.

[0020] According to aspect B2, the rapid cooling of aspect B1 reduces the temperature of the molten glass by at least 300 °C in less than 2 minutes.

[0021] According to aspect B3, the rapid cooling of aspect B1 results in a fictive temperature of at least 600 °C after solidification of the molten glass.

[0022] According to aspect B4, the temperature of aspect B1 is higher than 200 °C.

[0023] According to aspect B5, the constriction of aspect B4 further includes maintaining the glass generally at said temperature or above said temperature for at least one hour.

[0024] According to aspect B6, before the heating of aspect B4, the temperature of the glass is lower than 50 °C.

[0025] According to aspect C1, the glass-based article includes a glass portion and a cladding, wherein the glass portion compresses the cladding. A decrease in the fictive temperature of the glass of the glass portion from 600 °C to 450 °C causes its density to increase by at least 15 mg / cm 3 The fictive temperature of the glass of the glass portion is less than 300 °C lower than the softening temperature of the glass.

[0026] According to aspect C2, the glass portion of aspect C1 is a first glass portion, and the cladding is a second glass portion directly fused to the first glass portion.

[0027] According to aspect C3, the first glass portion and the second glass portion of aspect C2 have different compositions, and the glass of the first glass portion contains at least 5 mol% less SiO2 than the glass of the second glass portion.

[0028] According to aspect C4, the glass of the first glass portion of aspect C3 contains more B2O3 than the glass of the second glass portion.

[0029] According to aspect C5, the fictive temperature of the glass of the first glass portion of aspect C2 is lower than the fictive temperature of the glass of the second glass portion.

[0030] According to aspect C6, a decrease in the fictive temperature of the glass of the second glass portion of aspect C2 from 600 °C to 450 °C causes its density to increase by less than 10 mg / cm 3 .

[0031] According to aspect D1, the glass-based article includes a first glass portion and a second glass portion directly bonded to the first glass portion. The article has a stored compressive load-bearing capacity such that if the first glass portion is heated to 400 °C for 1 hour and then cooled to 25 °C, the compressive stress of the second glass portion increases.

[0032] According to aspect E1, a glass-to-glass laminate includes a first glass portion and a second glass portion fused to the first glass portion, wherein the fictive temperature of the glass of the first glass portion is higher than 600 °C. The laminate has a stored compressive load-bearing capacity such that if the glass-to-glass laminate is heat-treated at 400 °C for 24 hours at standard atmospheric pressure and sea-level pressure, then the volume shrinkage rate of the glass of the first glass portion is more than twice that of the glass of the second glass portion.

[0033] According to aspect E2, the glass of the second glass portion of aspect E1 has more silica than the glass of the first glass portion.

[0034] According to aspect E3, the glass of the first glass portion of aspect E1 has more boria than the glass of the second glass portion.

[0035] According to aspect E4, if the glass-to-glass laminate of aspect E1 is heat-treated at 400 °C for 24 hours at standard atmospheric pressure and sea-level pressure, then the volume shrinkage rate of the glass of the first glass portion is more than three times that of the glass of the second glass portion.

[0036] According to aspect F1, a glass-to-glass laminate includes a first glass portion and a second glass portion fused to the first glass portion. The glass of the second glass portion has the same composition as the glass of the first glass portion, but a fictive temperature that is at least 200 °C lower than that of the glass of the first glass portion. The laminate has a stored compressive load-bearing capacity such that if the glass-to-glass laminate is heat-treated at 400 °C for 24 hours at standard atmospheric pressure and sea-level pressure, then the volume shrinkage rate of the glass of the first glass portion is greater than that of the glass of the second glass portion.

[0037] Other features and advantages are set forth in the following detailed description, and some of the features and advantages will be readily apparent to those skilled in the art from the description or will be recognized by practicing the techniques described in the written description and its claims and the drawings. It should be understood that the foregoing general description and the following detailed description are merely exemplary and are intended to provide an overview or framework for understanding the nature and characteristics of the claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] The drawings are included to provide a further understanding, and are incorporated in and constitute a part of this specification. The drawings illustrate one or more aspects of the disclosure and, together with the detailed description, explain the principles and operations of the various aspects. Thus, the disclosure will be more fully understood from the following detailed description, taken in conjunction with the accompanying drawings, in which:

[0039] Figure 1Is a side view of an article in the form of a glass-to-glass laminate according to one aspect of the present disclosure.

[0040] Figure 2 Is a side cross-sectional view of another article according to one aspect of the present disclosure.

[0041] Figure 3 Is a side cross-sectional view of another article according to one aspect of the present disclosure.

[0042] Figure 4 Is a side cross-sectional view of another article according to one aspect of the present disclosure.

[0043] Figure 5 Is a graph showing the relationship between the density of different glasses and the fictive temperature.

[0044] Figure 6A Is a graph showing the relationship between the temperature and time of heat treatment.

[0045] Figure 6B Is at Figure 6A Under the heat treatment of, a graph showing the relationship between the change in length of four glass samples with the same composition but different initial fictive temperatures relative to the initial length and time.

[0046] Figure 7 Is a digital image of an article according to one aspect of the present disclosure.

[0047] Figure 8 Is Figure 7 A graph showing the change in Young's modulus of the glass of the article with temperature.

[0048] Figure 9 Is a graph showing the change with time of the ratio of the stress of the clad glass to the initial stress during five different heat treatment processes. Detailed Description

[0049] Before reading the following detailed description of the various aspects of the present disclosure and the drawings, it should be understood that the technology of the present invention is not limited to the details or methods set forth in the detailed description or illustrated in the drawings. For example, as will be understood by those of ordinary skill in the art, the features and properties related to one aspect shown in one drawing or described in the text with respect to one aspect can be applied to another aspect shown in another drawing or described elsewhere in the text.

[0050] The applicant has found that the compressive stress of glass can be increased by heat treatment, such as in the glass cladding of a glass-to-glass laminate, after the formation of the glass-to-glass laminate, the laminate is heat-treated at a temperature below the annealing range of the glass of the glass-to-glass laminate. More specifically, this increase in compressive stress can be achieved by causing the core glass to shrink to a greater extent relative to the cladding glass, where the shrinkage is caused by changes in the density of each glass layer. As disclosed herein, similar to other so-called "fictitious" properties of glass, the density of glass may vary due to its thermal history. The ability to controllably change the compressive stress of the laminate after its formation enables the glass to be cut / machined before the stress is increased, thereby increasing yield and reducing the risk of accidental breakage during such processing.

[0051] Referring Figure 1 , the glass-based article 100 includes a glass portion 102 and claddings 104a, 104b. The glass portion 102 is coupled to the claddings 104a, 104b, such as directly bonded (e.g., adhered, fixed, fused, i.e., joined by melting) to the claddings 104a, 104b at interfaces 103a, 103b. According to one aspect of the present disclosure, after bonding to the claddings 104a, 104b, the glass portion 102 has tightened from a previous (smaller) density to a larger density and compressed the claddings 104a, 104b, thereby strengthening the glass-based article 100. Alternatively, in an earlier state, the glass portion 102 may have had the ability to tighten from a smaller density to a larger density. For example, in one state, the density of the glass portion 102 can be lower, or it expands slightly upon solidification; then, once tightened, the glass portion 102 shrinks to a denser state, compressing the claddings 104a, 104b at interfaces 103a, 103b, thereby strengthening the glass-based article 100 by imparting corresponding crack resistance and fracture resistance to the claddings 104a, 104b.

[0052] According to one aspect of the present disclosure, more specifically, the glass portion 102 is a first glass portion 102, and Figure 1The claddings 104a, 104b therein are the second glass portions 104a, 104b. The glass of the first glass portion 102 may be different from the glass of the second glass portions 104a, 104b in composition and / or density. For example, compared with the glass of the second glass portions 104a, 104b, the density of the glass of the first glass portion 102 may be more dependent on the glass thermal history, such that when increasing the thermal history of the composite article, the density of the glass of the first glass portion 102 may increase more than the density of the glass of the second glass portions 104a, 104b, as further described herein. In other embodiments contemplated, the claddings 104a, 104b may be ceramic, glass-ceramic, metal, or other solid materials, wherein, as disclosed herein, when undergoing heat treatment, the claddings 104a, 104b shrink less than the glass portion 102.

[0053] Referring Figure 2 , another glass-based article 200 includes a glass portion 202 and a cladding 204. The glass portion 202 is coupled to the cladding 204, such as directly bonded (e.g., adhered, fixed, fused) to the cladding 204. According to one aspect of the present disclosure, the glass portion 202 has tightened from a previous (smaller) density to a larger density and compressed the cladding 204, thereby strengthening the glass-based article 200.

[0054] As Figure 2 shown, the glass-based article 200 may have a curvature, wherein the cladding 204 forms the outer or outward-facing portion of the glass article 200. For example, the glass-based article 200 may be Figure 2 a container shown in cross-section, wherein the cladding 204 forms the outer surface of the container; or the glass-based article 200 may be a curved sheet, cover glass, window, partition, electronic housing, etc., wherein the cladding 204 forms the outward-facing surface of the glass-based article 200. The cladding 204 may be glass and / or other materials, such as glass-ceramic, similar to Figure 1 the claddings 104a, 104b in Figures 3 - 4 and other aspects shown in

[0055] In Figure 2 , the cladding 204 of the article 200 is present only on one side of the glass portion 202. Thus, when the glass portion 202 tightens, the glass portion 202 may compress the cladding 204 and / or may also apply a bending force to the cladding 204, thereby causing the article 200 to have a curvature, wherein the glass portion 202 forms an inwardly concave well 206. If the article 200 is a container or reservoir, a liquid, such as a drug, may be stored in the well 206. The article 200 may also be capped and may have additional contours, such as a neck, an edge, etc.

[0056] Now referring Figure 3, Another glass-based article 300 includes a glass portion 302 and a cladding 304. The glass portion 302 is coupled to the cladding 304, such as directly bonded (e.g., adhered, fixed, fused) to the cladding 304. According to one aspect of the present disclosure, the glass portion 302 has been densified from a previous (lower) density to a greater density, and the cladding 204 is compressed, thereby strengthening the glass-based article 200.

[0057] In Figure 3 , the cladding 304 completely surrounds the glass portion 302. For example, Figure 3 the article 300 in Figure 3 can be a sphere, where the glass portion 302 is a solid core and the cladding 304 completely wraps the core. Alternatively, the glass portion 302 can be cylindrical, rod-shaped, pill-shaped, etc., where the cladding at least surrounds the central region of such a geometry. Alternatively, the applicant contemplates that the glass portion 302 can be tubular or vesicular with an open or hollow center, where the cladding forms an outer layer surrounding the exterior of the glass portion, similar to the cladding arrangement in

[0058] Similar to the claddings 104a, 104b, and 204 of the articles 100, 200 in Figures 1 - 2 , the glass portion 302 can be a first glass portion, and the cladding 304 also includes (e.g., is, mostly is, at least partly is) glass and can thus be characterized as a second glass portion of the article 300. According to one aspect of the present disclosure, the glass of the second glass portion may be different in composition from the glass of the first glass portion, as further discussed herein, where if the two glass portions are subjected to the same heat treatment and are coupled in the article 300, then the glass of the second glass portion may react differently to the heat treatment than the glass of the first glass portion. Alternatively, the applicant contemplates that the glass of the second glass portion can have the same composition as the glass of the first glass portion but instead have a different density, as further illustrated with respect to the article 400 in Figure 4 .

[0059] Referring to Figure 4 , the article 400 includes a glass portion 402 and a cladding 404. The glass portion 402 is coupled to the cladding 404, such as directly bonded (e.g., adhered, fixed, fused) to the cladding 404. More specifically, the article 400 is a single, continuous entity with a uniform glass composition continuously extending throughout the article 400, where the density of the glass varies significantly with the thermal history or heat treatment (e.g., a change > 10 mg / cm3 as the fictive temperature drops from 650 °C to 450 °C, such as a change > 15, > 20, > 25, > 30 mg / cm3 as the fictive temperature drops from 650 °C to 450 °C). As Figure 4As shown, the article 400 can be arranged in a sheet form, or the article can be arranged in other ways (such as a container, a pipe).

[0060] According to one aspect of the present disclosure, a glass portion 402, i.e., the first portion of the glass, has been tightened from a previous (lower) density to a higher density, and the cladding 404, i.e., the second portion of the glass, is compressed. The glass portion 402 can be tightened by locally heat-treating the glass portion 402, such as using a laser, without heating the cladding 404. For example, by providing a heat sink for the cladding, the heating of the glass portion 402 will not be transferred to the cladding 404 and cause the cladding to tighten.

[0061] Referring to articles 100, 200, 300, 400, the applicant has found that stress can be increased by low-temperature heat treatment (e.g., compression of the claddings 104a, 104b, 204, 304, 404 and corresponding tensile forces in the glass portions 102, 202, 302, 402), and the low-temperature heat treatment is below the glass transition temperature of the corresponding glass portions 102, 202, 302, 402. This process enables the glass of the articles 100, 200, 300, 400 to have lower stress during glass formation, thus facilitating handling (e.g., separation from a drawing machine, edge treatment, transportation, and other processes). Then, the glass is heat-treated again to increase the stress. In addition, during this process, the stress or energy storage level of the articles 100, 200, 300, 400 can be higher than that at the initial formation, such as when leaving a melting and drawing machine. This higher stress can enable the articles 100, 200, 300, 400 to have better retention strength after being damaged and can replace ion exchange to increase the compressive stress of the claddings 104a, 104b, 204, 304, 404, and the claddings can be located at or near the outer surface of the articles 100, 200, 300, 400. This process can also be combined with ion exchange strengthening.

[0062] During low-temperature heat treatment (e.g., below the glass transition temperature of the corresponding glass portion; below 600 °C, such as below 550 °C, such as below 500 °C, such as below 450 °C, such as within 150 °C to 400 °C, such as within 100 °C to 400 °C, where the heat treatment generally lasts at least 30 minutes, such as at least 90 minutes, such as at least 60 minutes, such as at least 2 hours, such as at least 4 hours), the density of the glass portions 102, 202, 302, 402 and the claddings 104a, 104b, 204, 304, 404 will increase compared to the previous density corresponding to a higher fictive temperature. During the heat treatment, the glass portions 102, 202, 302, 402 shrink more than the claddings 104a, 104b, 204, 304, 404, causing the stress of the articles 100, 200, 300, 400 to increase.

[0063] In other words, when the glass portions 102, 202, 302, 402 have a lower density due to the relatively fast cooling rate of the glass of the glass portions 102, 202, 302, 402, the articles 100, 200, 300, 400 can be assembled (e.g., melt molding, bonding, welding, adhesion). Then, at a temperature below the annealing range of the glass of the glass portions 102, 202, 302, 402, subsequent heat treatment is performed on the glass of the glass portions 102, 202, 302, 402, such that the density of the glass of the glass portions 102, 202, 302, 402 increases (the corresponding fictive temperature decreases), thereby causing the glass portions 102, 202, 302, 402 to shrink relative to the claddings 104a, 104b, 204, 304, 404 (structural relaxation).

[0064] According to one aspect of the present disclosure, the articles 100, 200, 300, 400 can be heat treated, and the glass portions 102, 202, 302, 402 and the claddings 104a, 104b, 204, 304, 404 can experience similar temperatures, such as when the heat treatment is performed in a furnace, oven, annealing furnace, etc. However, according to one aspect of the present disclosure, the material of the claddings 104a, 104b, 204, 304, 404 shrinks less than the glass portions 102, 202, 302, 402 after the heat treatment and is correspondingly compressed by the glass portions 102, 202, 302, 402. In addition, as shown above, the glass portions 102, 202, 302, 402 can be the first glass portions, and the claddings 104a, 104b, 204, 304, 404 can also include glass and are the second glass portions of the corresponding articles 100, 200, 300, 400.

[0065] Now referring to Figure 5 , which shows the relationship between the density of the glass and the fictive temperature, the frozen solid state of the glass generally corresponds to the cooling rate of the glass, such as glass compositions A and B (the compositions are shown in Table 1 below). It can be seen that between fictive temperatures of about 450 °C and 650 °C, the density change of glass B is about 35 mg / cm 3 , while the density change of glass A is about 7 mg / cm 3 .

[0066] Table 1

[0067] mol% A B <![CDATA[SiO2]]> 72.43 66.53 <![CDATA[Al2O3]]> 9.03 10.97 <![CDATA[B2O3]]> 9.74 <![CDATA[P2O5]]> <![CDATA[Li2O]]> 3.86 <![CDATA[Na2O]]> 12.55 8.3 <![CDATA[K2O]]> 3.89 MgO 2 0.5 <![CDATA[SnO2]]> 0.1 0.1

[0068] To further illustrate the effect of the fictive temperature on the density of the glass and how the density can be changed by changing the fictive temperature through heat treatment, Figure 6B shows glass B starting from 4 different fictive temperatures, and the samples atFigure 6A The shrinkage in the heat treatment cycle shown in Figure 6A , where the Y-axis is the change in length relative to the initial length, in parts per million. As the temperature increases, each sample initially expands. However, the samples with higher initial fictive temperatures (e.g., 600 °C and 536 °C) shrink significantly more after about 24 hours than the samples with lower initial fictive temperatures (e.g., 600 °C and 536 °C). Additionally, after the heat treatment is complete, the samples with higher initial fictive temperatures can shrink by up to about 1000 ppm relative to their initial size.

[0069] For example, Glass A and Glass B are examples of glasses that can be paired with each other, where if they are heat treated together and have the same starting fictive temperature, they will shrink at different rates. However, the applicant believes that according to the general principles explained now, other glasses can also be paired for this purpose.

[0070] First, the applicant has found that adding or increasing silica in the glass composition reduces the ability to change the fictive temperature-related properties of the corresponding glass, such as density, Young's modulus, refractive index, shear modulus, coefficient of thermal expansion, etc. For example, a ternary glass with equal amounts of CaO and Al2O3 and 60 mol% SiO2 has a change in Young's modulus (in GPa) of -0.0215 / °C in the fictive temperature range from 750 °C to 850 °C, while a ternary glass with equal CaO and Al2O3 content but 80 mol% SiO2 has a change in Young's modulus of only -0.001 / °C in the same fictive temperature range. The slopes of the density-related curves for Glass A and B and Figure 5 also demonstrate this relationship.

[0071] According to one aspect of the present disclosure, for glass-to-glass laminates 100, 200, 300, 400, where the glass portions 102, 202, 302, 402 are the first glass portions, the claddings 104a, 104b, 204, 304, 404 are the second glass portions, and the glass composition of the second glass portion is different from that of the first glass portion, the silica content of the first glass portion (e.g., the core; i.e., the glass that is more responsive in terms of density change with respect to fictive temperature) is less than that of the glass of the second glass portion, i.e., the claddings 104a, 104b, 204, 304, 404 of the articles 100, 200, 300, 400. For example, the silica content of the glass of the first glass portion is at least 3 mol% lower, such as 5 mol% lower, such as at least 8 mol% lower, such as at least 10 mol% lower than that of the glass of the second glass portion. According to one aspect of the present disclosure, the glass of the glass portions 102, 202, 302, 402 is not pure silica, e.g., the silica content is less than 90 mol%, such as less than 80 mol%, such as less than 70 mol%, such as less than 60 mol%.

[0072] Similarly, the applicant has found that replacing at least part of the silica (SiO2) with boron oxide (B2O3) in the glass composition can improve the ability to change the glass properties (such as density, Young's modulus) affected by fictive temperature by heat treatment at a reduced fictive temperature. For example, when measured at a fictive temperature of about 600 °C to 800 °C, for the 0.15CaO·0.15Al2O3·(x)B2O3·(0.7 - x)SiO2 glass, when x is 0.05, the slope of the change in Young's modulus (GPa) with respect to fictive temperature (°C) is -0.0317. In contrast, when x is 0.24, i.e., a larger amount of B2O3 replaces SiO2, the slope is -0.0608.

[0073] According to one aspect of the present disclosure, for glass-to-glass laminates 100, 200, 300, 400, where the glass portions 102, 202, 302, 402 are the first glass portions and the claddings 104a, 104b, 204, 304, 404 are the second glass portions having a glass composition different from that of the first glass portions, the first glass portions have more boron trioxide than the glass of the second glass portions, i.e., the claddings 104a, 104b, 204, 304, 404 of the articles 100, 200, 300, 400. For example, the glass of the first glass portion has at least 2 mol% more boron trioxide than the glass of the second glass portion, such as 3 mol% more, such as at least 5 mol% more, such as at least 8 mol% more. According to one aspect of the present disclosure, the glass of the glass portions 102, 202, 302, 402 has at least some boron trioxide, such as at least 2 mol%, such as at least 3 mol%, such as at least 5 mol%, and / or not more than 35 mol%.

[0074] In addition, according to general principles, the applicant has found that glass compositions using smaller (in terms of ionic radius) alkali metal species tend to have a stronger ability to freeze in a modified state and then be altered. Thus, glass containing lithium as a component has a stronger ability to freeze in a modified state and then be altered than glass containing sodium as a component, and glass containing sodium as a component has a stronger ability than glass containing potassium as a component. For example, when R2O is Li2O in a 20 mol% R2O, 10 mol% Al2O3, and 70 mol% SiO2 glass, the slope of the change in the Young's modulus (GPa) of the glass with respect to the fictive temperature (°C) is -0.0324 when measured at a fictive temperature of about 450 °C to 650 °C. When the R2O of this glass is changed to Na2O, the slope is -0.0301; and when R2O is K2O, the slope is -0.0227.

[0075] According to one aspect of the present disclosure, for glass-to-glass laminates 100, 200, 300, 400, where the glass portions 102, 202, 302, 402 are the first glass portions and the claddings 104a, 104b, 204, 304, 404 are the second glass portions having a glass composition different from that of the first glass portions, the glass of the first glass portions has more smaller (in terms of ionic radius) alkali metal species than the glass of the second glass portions. For example, it has more lithium than the glass of the second glass portion, or the glass of the first glass portion has more Na2O while the glass of the second glass portion has more K2O.

[0076] However, the applicant has also found that mixing different alkali metals produces the opposite effect, and the effect of mixing different alkali metals is not merely the average of glasses having a single alkali metal component. For example, when R2O is 10 mol% Li2O, 10 mol% Na2O, 10 mol% Al2O3, and 70 mol% SiO2 in 20 mol% R2O glass, when measured at a fictive temperature of about 450 °C to 650 °C, the slope of the Young's modulus (GPa) versus fictive temperature (°C) is -0.0249; when R2O is 10 mol% Na2O and 10 mol% K2O, the slope is -0.0184.

[0077] According to one aspect of the present disclosure, for glass-to-glass laminates 100, 200, 300, 400, wherein the glass portions 102, 202, 302, 402 are first glass portions and the claddings 104a, 104b, 204, 304, 404 are second glass portions having a glass composition different from that of the first glass portions, the glass of the first glass portions has a mixture of alkali metal oxides, such as at least two different alkali metal oxides and / or at least three different alkali metal oxides in an amount of at least 2 mol%.

[0078] Regardless of the composition selected in the glasses of the glass portions 102, 202, 302, 402 and the claddings 104a, 104b, 204, 304, 404 of the articles 100, 200, 300, 400 to achieve a specific glass composition, if the cladding is glass, then the glass of the glass portions 102, 202, 302, 402 should have a higher ability to be frozen in a modified state (e.g., relatively low density) and subsequently changed (e.g., significantly shrunk). With respect to Figure 5 the curves in, the glass of the glass portions 102, 202, 302, 402 has a rate of change of density (Δρ) versus fictive temperature (ΔT f ) in the range of fictive temperature from 450 °C to 650 °C of at least 10 mg / 200 °C, such as at least 15 mg / 200 °C, such as at least 20 mg / 200 °C, such as at least 25 mg / 200 °C, such as at least 30 mg / 200 °C. For articles 100, 200, 300, 400 in which the claddings 104a, 104b, 204, 304, 404 are second glass portions, the glass of the second glass portions has a Δρ / ΔT f less than that of the glass of the first glass portions, such as at least 10 mg / 200 °C less, such as at least 15 mg / 200 °C less, such as at least 20 mg / 200 °C less, such as at least 25 mg / 200 °C less.

[0079] Referring to Figure 7, the glass-to-glass laminate 700 includes a first glass portion 702 (“core”) bonded to a second glass portion 704 (“cladding”). The laminate 700 is made by heat-treating a cladding-core-cladding glass stack at 929 °C (the softening point of the cladding glass) for 10 minutes and then rapidly cooling the laminate 700 in air using a fan. Each layer of the laminate 700 (i.e., the cladding, core, cladding glass) contains a glass sheet of 20×40×0.6 mm, the surface of the glass sheet is polished, and the edges are precision sawed to prevent cracking after cooling. The rapid cooling is used to set a relatively high initial fictive temperature (e.g., >600 °C) in the glass of the glass laminate 700. As can be seen from Figure 7 , both of these glasses are optically translucent and / or transparent (e.g., transmitting >60% / mm, such as >70%, such as >80% through a spectrum with a thickness exceeding 380 - 700 nm). The first and second glass portions 702 and 704 are fused to each other. For articles 100, 200, 300, 400, in the case where the article is a glass-to-glass laminate, the glass portion 102, 202, 302, 402 or the first glass portion can be the “core” glass, and the cladding 104a, 104b, 204, 304, 404 or the second glass portion can be the “cladding” glass. Figure 7 The special arrangement in

[0080] is most similar to article 100.

[0081] Table 2

[0082] mol% core cladding <![CDATA[SiO2]]> 45.66 59.7 <![CDATA[Al2O3]]> 15.04 15.06 <![CDATA[B2O3]]> 23.5 14.8 CaO 15.38 10.12 <![CDATA[Na2O]]> 0.06 0.05 <![CDATA[K2O]]> 0.02 0.01 MgO 0.32 0.22 <![CDATA[Fe2O3]]> 0.02 0.01 Cl 0.01 0.02

[0083] For example, Figure 8 compares the Young's modulus of the core glass and the cladding glass at different temperatures, where the slope of the core glass is greater. For the curves in Figure 8 , the glass of the glass portion 102, 202, 302, 402 (e.g., the core glass) has a rate of change of Young's modulus (ΔE) with respect to fictive temperature (ΔT f ) in the fictive temperature range of 600 °C to 750 °C of at least 4 GPa / 150 °C, such as at least 6 GPa / 150 °C, such as at least 8 GPa / 150 °C, such as at least 10 GPa / 150 °C. For articles 100, 200, 300, 400 where the cladding 104a, 104b, 204, 304, 404 is the second glass portion (e.g., the cladding glass), the ΔE / ΔT of the glass of the second glass portion in the fictive temperature range of 600 °C to 750 °Cf Glass that is less than the first glass portion, e.g., at least 1 GPa / 150 °C less, e.g., at least 2 GPa / 150 °C less, e.g., at least 3 GPa / 150 °C less, e.g., at least 5 GPa / 150 °C less.

[0084] To demonstrate the prior art, the laminate 700 was replicated five times (i.e., five independent samples) and heat-treated at 5 temperatures: 400 °C, 450 °C, 500 °C, 550 °C, and 600 °C, each for 15 days. The stress before heat treatment was measured using a Scattering Polariscope (SCALP). Each SCALP measurement is the average and standard deviation of measurements at 4 - 6 positions (e.g., the positions at the center of each quadrant) on the sample. Then, the samples were continuously heat-treated over time, removed from the furnace, allowed to cool in air, and the stress was measured using SCALP at each step. Figure 9 It is a graph of the ratio of the cladding stress on the Y-axis to the initial cladding stress versus time on the X-axis under heat treatment, in units of the square root of days.

[0085] As Figure 9 shown, when heat-treated at all temperatures except 600 °C, the stress in the cladding glass increases, at least the initial stress increases. The ratio of the cladding compressive stress to the initial compressive stress reaches a maximum after five days of heat treatment at 400 °C. After five days, the stress ratio decreases. For 450 °C, the peak stress ratio also occurs after five days. For 500 °C and 550 °C, the stress ratio initially increases, e.g., within the first 30 minutes, 60 minutes, or several hours, but then decreases. At 600 °C, the stress ratio does not increase, and there is only a decrease in the compressive stress of the cladding glass.

[0086] Notably, the temperature that causes the stress ratio to increase is lower than the softening point of the cladding glass of 929 °C, e.g., more than 100 °C lower, e.g., more than 200 °C lower, e.g., more than 300 °C lower. Additionally, the temperature that causes the stress ratio to increase is lower than the glass transition temperature T0 (°C) of the cladding glass, i.e., 678.4 °C for the cladding, e.g., more than 100 °C lower, e.g., more than 200 °C lower, e.g., more than 300 °C lower; and similarly, it is also lower than the 200 Poise temperature, 35 kP temperature, and 200 kP temperature of the cladding. Similarly, the heat treatment temperature that causes the largest increase in the cladding stress is lower than the softening point of the core glass, lower than the 200 Poise temperature, 35 kP temperature, and 200 kP temperature of the core glass, and in some cases lower than the T0 (°C) of the core glass, i.e., 460.8 °C, e.g., more than 100 °C lower than these critical temperatures, e.g., more than 200 °C lower, e.g., more than 300 °C lower.

[0087] The magnitude of the compressive stress in the claddings 104a, 104b, 204, 304, 404 of the articles 100, 200, 300, 400 disclosed herein can be controlled by the following conditions: the relative thickness of the glass portions 102, 202, 302, 402 compared to the claddings 104a, 104b, 204, 304, 404; the difference in the responsiveness of the glass portions 102, 202, 302, 402 and the claddings 104a, 104b, 204, 304, 404 to a hypothetical temperature change; and the starting or initial hypothetical temperature and corresponding density of the glass portions 102, 202, 302, 402. Thus, all other factors being equal, the thicker the glass portions 102, 202, 302, 402 and the greater their responsiveness to a hypothetical temperature change, the greater the compressive stress in the claddings 104a, 104b, 204, 304, 404 upon transition from a higher hypothetical temperature.

[0088] According to one aspect of the present disclosure, for the articles 100, 200, 300, 400, after heat treatment strengthening by the techniques of the present disclosure, the compressive stress in the claddings 104a, 104b, 204, 304, 404 can be at least 5 MPa, such as at least 10 MPa, such as at least 20 MPa, such as at least 30 MPa, such as at least 50 MPa, such as at least 100 MPa, such as at least 200 MPa, such as at least 300 MPa, such as at least 500 MPa, such as at least 1 GPa, such as at least 2 GPa, such as at least 3 GPa, such as at least 5 GPa, and / or not more than 10 GPa, such as not more than 5 GPa, such as not more than 2 GPa, such as not more than 1 GPa. The tensile stress in the glass portions 102, 202, 302, 402 after heat treatment strengthening by the techniques of the present disclosure can be at least 5 MPa, such as at least 10 MPa, such as at least 20 MPa, such as at least 30 MPa, such as at least 50 MPa, such as at least 100 MPa, such as at least 200 MPa, such as at least 300 MPa, such as at least 500 MPa, such as at least 1 GPa, such as at least 2 GPa, such as at least 3 GPa, such as at least 5 GPa, and / or not more than 10 GPa, such as not more than 5 GPa, such as not more than 2 GPa, such as not more than 1 GPa.

[0089] The heat treatment time of the articles 100, 200, 300, 400 disclosed herein can be adjusted so that the compressive stress in the claddings 104a, 104b, 204, 304, 404 is below the brittle limit of the cladding. At the brittle limit, glass fracture releases the stored energy in the glass, causing the glass to break into multiple parts (e.g., more than 3 different fragments), the initial crack to bifurcate, and at the brittle limit (if unconstrained), small fragments of the glass may pop out. In some applications, it may be undesirable for the articles 100, 200, 300, 400 to exceed the brittle limit, so the heat treatment can be timed such that the articles 100, 200, 300, 400 are below the brittle limit but less than 200 MPa; for example, below the brittle limit but less than 100 MPa; for example, below the brittle limit but less than 50 MPa; for example, below the brittle limit but less than 20 MPa.

[0090] The Applicant contemplates that the articles 100, 200, 300, 400 can be made of the glass portions 102, 202, 302, 402 and the claddings 104a, 104b, 204, 304, 404, which are substantially the same in composition and are both glass, but the glass portions 102, 202, 302, 402 initially have a higher imaginary temperature and a correspondingly lower density than the claddings 104a, 104b, 204, 304, 404, and during the heat treatment process, the glass portions 102, 202, 302, 402 shrink more than the claddings 104a, 104b, 204, 304, 404. Alternatively, as discussed with respect to Figure 4 Article 400, after undergoing heat treatment, the glass portion 404 can shrink more than the cladding 402.

[0091] Although the article 700 is manufactured as described above, the Applicant contemplates that a duel-fusion isopipe may be a useful method for manufacturing the glass-to-glass laminates disclosed herein. Two separate streams of molten glass flow out of the overflow trough, overlap each other, and form a glass ribbon, which is typically a cladding-core-cladding type structure (see Figure 1 ), and then it can be cut into thin sheets. Alternatively, the glass disclosed herein can be made into the articles 100, 200, 300, 400 by being molded together, rolled, float formed, or otherwise formed.

[0092] The construction and arrangement of the compositions, structures, assemblies, and structures shown in the various aspects are merely illustrative. Although only a few examples of many aspects are described in detail in this disclosure, many modifications are possible without materially departing from the novel teachings and advantages of the subject matter described herein (e.g., variations in the size, dimensions, structure, shape, and proportions of the various elements, parameter values, mounting arrangements, use of materials, colors, orientations, etc.). The order or sequence of any process, logical algorithm, or method step can be changed or reordered according to alternative embodiments. Other substitutions, modifications, changes, and omissions in design, operating conditions, and arrangement can also be made to the various aspects without departing from the scope of the technology of the present invention.

Claims

1. A method of manufacturing a strengthened glass-based article, comprising: By tightening the glass from a first density to a second density that is at least 10 mg / cm greater than the first density to at least partially compress the cladding bonded to the glass, 3 ​ Among them, The tightening occurs when the glass is heated to a temperature above 100 °C and below the softening temperature of the glass, whereby the tightened glass compresses the cladding, thereby strengthening the glass-based article.

2. The method according to claim 1, further comprising cutting the glass-based article before the tightening.

3. The method according to claim 1, further comprising polishing at least a portion of the glass-based article before the tightening.

4. The method according to claim 1, wherein the temperature is above 200 °C.

5. The method according to claim 4, wherein the tightening further comprises maintaining the glass generally at or above the temperature for at least one hour.

6. The method according to claim 4, wherein before the heating, the temperature of the glass is below 50 °C.

7. The method according to claim 1, wherein the glass is a first glass portion, and wherein the cladding is a second glass portion.

8. The method according to claim 7, wherein the first glass portion and the second glass portion have different compositions, and wherein the glass of the first glass portion contains at least 5 mol% less SiO2 than the glass of the second glass portion.

9. The method according to claim 8, wherein the glass of the first glass portion contains more B2O3 than the glass of the second glass portion.

10. The method according to claim 7, wherein the second glass portion is directly fused to the first glass portion.

11. The method according to claim 10, wherein the first glass portion is located inside the second glass portion such that the second glass portion covers at least two opposite faces of the first glass portion.

12. The method according to claim 7, wherein the fictive temperature of the glass of the first glass portion is lower than that of the glass of the second glass portion.

13. A method of manufacturing a strengthened glass-based article, comprising: Rapidly cooling molten glass; Bonding the glass to a cladding; In the case of bonding with the cladding, the glass is heated to a temperature higher than 100 °C and lower than the softening temperature of the glass to increase the density of the glass by at least 10 mg / cm 3 , and During heating, by tightening the glass bonded to the cladding, compressive stress is applied to the cladding, thereby compressing the cladding.

14. The method according to claim 13, wherein the rapid cooling reduces the temperature of the molten glass by at least 300 °C in less than 2 minutes.

15. The method according to claim 13, wherein the fictive temperature of the molten glass after solidification is at least 600 °C.

16. The method according to claim 13, wherein the temperature is above 200 °C.

17. The method according to claim 16, wherein the tightening further comprises maintaining the glass generally at or above the temperature for at least one hour.

18. The method according to claim 16, wherein before the heating, the temperature of the glass is below 50 °C.

19. A glass-based article, comprising: A glass portion; and A cladding, wherein the glass portion compresses the cladding; Among them, A decrease in the fictive temperature of the glass in the glass portion from 600 °C to 450 °C will increase its density by at least 15 mg / cm 3 ; and Wherein, the fictive temperature of the glass of the glass portion is less than 300 °C lower than the softening temperature of the glass.

20. The article according to claim 19, wherein the glass portion is a first glass portion, and the cladding is a second glass portion directly fused to the first glass portion.

21. The article according to claim 20, wherein the first glass portion and the second glass portion have different compositions, and wherein the glass of the first glass portion contains at least 5 mol% less SiO2 than the glass of the second glass portion.

22. The article according to claim 21, wherein the glass of the first glass portion contains more B2O3 than the glass of the second glass portion.

23. The article according to claim 20, wherein the fictive temperature of the glass of the first glass portion is lower than that of the glass of the second glass portion.

24. The article according to claim 20, wherein decreasing the fictive temperature of the glass of the second glass portion from 600 °C to 450 °C results in an increase in density of less than 10 mg / cm 3 .

25. A glass-based article, comprising: A first glass portion; and A second glass portion directly bonded to the first glass portion; Among them, The article has a stored compressive load-bearing capacity such that if the first glass portion is heated to 400 °C for 1 hour and then cooled to 25 °C, the compressive stress of the second glass portion will increase.

26. A glass-to-glass laminate, comprising: A first glass portion, wherein the fictive temperature of the glass of the first glass portion is higher than 600 °C; and A second glass portion fused to the first glass portion; Among them, The laminate has a stored compressive load-bearing capacity such that if the glass-to-glass laminate is heat-treated at 400 °C for 24 hours under standard atmospheric pressure and sea-level pressure, the volume shrinkage rate of the glass of the first glass portion is more than twice that of the glass of the second glass portion.

27. The laminate according to claim 26, wherein the glass of the second glass portion has more silica than the glass of the first glass portion.

28. The laminate according to claim 26, wherein the glass of the first glass portion has more boria than the glass of the second glass portion.

29. The laminate according to claim 26, wherein, If the glass-to-glass laminate is heat-treated at 400 °C for 24 hours under standard atmospheric pressure and sea-level pressure, the volume shrinkage rate of the glass of the first glass portion is more than three times that of the glass of the second glass portion.

30. A glass-to-glass laminate, comprising: A first glass portion; and A second glass portion fused to the first glass portion, wherein the glass of the second glass portion has the same composition as the glass of the first glass portion, but the fictive temperature is at least 200 °C lower than that of the glass of the first glass portion; Among them, The laminate has a stored compressive load-bearing capacity such that if the glass-to-glass laminate is heat-treated at 400 °C under standard atmospheric pressure and sea-level pressure for 24 hours, the volume shrinkage rate of the glass of the first glass portion is greater than that of the glass of the second glass portion.

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