阅读说明：本技术 抗脱层的玻璃容器 (Delamination resistant glass container ) 是由 K·阿迪比 P·S·丹尼尔森 J·P·汉密尔顿 R·M·莫伦纳 J·S·皮纳斯基 R·A· 于 2013-06-07 设计创作，主要内容包括：揭示抗脱层的玻璃容器及其形成方法的实施方式。依据一个实施方式,一种抗脱层的玻璃容器可以包括玻璃制品,该玻璃制品具有延伸于内表面和外表面之间的主体。该主体界定出内部容积。该主体可以包括内部区域,该内部区域从该主体的该内表面下方约10nm处延伸进入该主体的厚度。该内部区域具有持久层均匀性,使得该主体为抗脱层的。(Embodiments of delamination resistant glass containers and methods of forming the same are disclosed. According to one embodiment, a delamination resistant glass container may include a glass article having a body extending between an inner surface and an outer surface. The body defines an interior volume. The body may include an interior region extending into a thickness of the body from about 10nm below the interior surface of the body. The inner region has a persistent layer uniformity such that the body is resistant to delamination.)

1. A delamination resistant glass container comprising:

a glass article having a glass body extending between an inner surface and an outer surface and defining an interior volume, wherein the glass body comprises X mol.% Al₂O₃And comprises Ymol.% of an alkali metal oxide, and wherein the Y: X ratio is greater than 0.9;

an inner region extending into a thickness of the body from 10nm below the inner surface of the body, and the inner region having a persistent layer uniformity in as-formed conditions such that the body is resistant to delamination, wherein an extrema in a layer concentration of each constituent component of the glass in the inner region is greater than or equal to about 80% and less than or equal to about 120% of an overall concentration of a same constituent component in the glass at a midpoint of the thickness of the glass body when the glass container is in an as-formed condition; wherein the inner region has a thickness T_LRThe thickness T_LRIs at least 100 nm.

2. The glass container of claim 1, wherein the glass article is formed from a glass composition having a 1000 poise temperature less than or equal to 1700 ℃.

3. The glass container of claim 1, wherein the glass article is formed from a glass composition comprising less than or equal to 1.0 mol% of each of a boron-containing compound, less than or equal to 0.3 mol% of a phosphorous-containing compound, and less than or equal to 0.5 mol% of a zinc-containing compound.

4. The glass container of claim 1, wherein the glass article is formed from a glass composition comprising less than 0.05 mol.% of a substance that forms an equilibrium partial pressure greater than 10 at a temperature^-3Atmospheric pressure, at which the glass composition has a viscosity, and the viscosity is in a range from 200 poise to 100 kpoise.

5. The glass container of claim 1, wherein the glass container comprises a compressive stress greater than or equal to 300mpa and a depth of layer greater than or equal to 10 μ ι η.

6. The glass container of any of claims 1-5, wherein:

the body further comprises a surface region extending on the inner surface of the glass container to a depth from 10nm to 50nm from the inner surface of the glass container; and

the surface region has a persistent surface uniformity such that the glass body is delamination resistant.

7. The glass container of any of claims 1-5, wherein the glass body has a delamination factor less than or equal to 10.

8. The glass container of any of claims 1-5, wherein:

the body further comprises a surface region extending on the inner surface of the glass container to a depth from 10nm to 50nm from the inner surface of the glass container; and

an extremum in a surface concentration of each constituent component of the glass at a discrete point on the inner surface of the glass container when the glass container is in an as-formed condition is greater than or equal to 70% and less than or equal to 130% of an extremum in a surface concentration of an identical constituent component at any second discrete point in the surface region on the inner surface of the glass container at the discrete point in the surface region.

9. The glass container of claim 8, wherein an extremum in a layer concentration of each constituent component in the interior region is greater than or equal to 90% and less than or equal to 110% of an overall concentration of a same constituent component at the thickness midpoint of the glass body when the glass container is in an as-formed condition.

Technical Field

Historically, glass has been used as a preferred drug packaging material due to its hermetic properties, optical transparency, and excellent chemical durability relative to other materials. In particular, glass used for pharmaceutical packaging must have sufficient chemical durability so as not to affect the stability of the pharmaceutical composition contained therein. Glasses having suitable chemical durability include those glass compositions within ASTM standard E438.92 "type 1 a" and "type 1 b" glass compositions having a proven history of chemical durability. Generally, chemically durable glass refers to glass whose constituent components do not leach out of the glass when the glass is contacted with a solution for an extended period of time.

Although type 1a and type 1b glass compositions are commonly used in pharmaceutical packaging due to their chemical durability, they still suffer from several deficiencies, including a tendency for the interior surfaces of the pharmaceutical packaging to shed glass particles or "delaminate" after contacting a pharmaceutical solution.

Accordingly, there is a need for alternative glass containers that exhibit a reduced tendency to delaminate.

Background

The present description relates generally to glass containers and more particularly to glass containers that are resistant to delamination.

Summary of The Invention

According to one embodiment, a delamination resistant glass container may include a glass article having a glass body extending between an inner surface and an outer surface and defining an interior volume. The glass article may also include an inner region extending into a thickness of the body from about 10nm below the inner surface of the body, the inner region having a persistent layer uniformity such that the body is resistant to delamination.

In another embodiment, a delamination resistant glass container may include a glass article having a glass body extending between an inner surface and an outer surface and defining an interior volume, the glass body having a delamination factor less than or equal to 10.

In another embodiment, a delamination resistant glass container may include a glass article having a glass body extending between an inner surface and an outer surface, and the glass body defining an interior volume. An inner region may extend into the thickness of the body from about 10nm below the inner surface of the body, and the inner region has a persistent layer uniformity. The glass body can have a delamination factor of less than or equal to 10.

In another embodiment, a delamination resistant glass container may include a glass article formed from an ion-exchangeable glass composition. The glass article may have a glass body extending between an inner surface and an outer surface, and the glass body defines an interior volume. The inner region may extend into the thickness of the body from about 10nm below the inner surface of the body, and the inner region has a thickness T_LRThe thickness T_LRIs at least about 100 nm. When the glass container is usedAn extremum in the layer concentration of each constituent component of the ion-exchangeable glass composition in the inner region when in an as-formed condition may be greater than or equal to about 80% and less than or equal to about 120% of a total concentration of the same constituent component in the glass composition at the thickness midpoint of the glass body.

In another embodiment, a delamination resistant glass container may include a glass article having a glass body extending between an inner surface and an outer surface, and the glass body defining an interior volume. The surface region may extend over the entire inner surface of the glass container and have a depth extending from the inner surface of the glass container into the thickness of the body. The surface region can have a persistent surface uniformity such that the glass body is delamination resistant.

In another embodiment, a delamination resistant glass container may include a glass article having a glass body extending between an inner surface and an outer surface, and the glass body defining an interior volume. The surface region may extend over the entire inner surface of the glass container and have a depth extending from the inner surface of the glass container into the thickness of the body. The surface region may have a persistent surface uniformity. The glass body can have a delamination factor of less than or equal to 10.

In another embodiment, a delamination resistant glass container may include a glass article formed from an ion exchangeable glass composition. The glass article may have a glass body extending between an inner surface and an outer surface, and the glass body defines an interior volume. The surface region may extend on the inner surface of the glass container to a depth of about 10nm from the inner surface of the glass container. For a discrete point on the inner surface of the glass container when the glass container is in an as-formed condition, an extremum in a surface concentration of each constituent component at the discrete point in the surface region may be greater than or equal to about 70% and less than or equal to about 130% of an extremum in a surface concentration of the same constituent component at any second discrete point in the surface region on the inner surface of the glass container.

In another embodiment, a method of forming a delamination resistant glass container includes providing a feedstock formed from a delamination resistant glass composition. Forming the raw material into a glass article having a glass body extending between an inner surface and an outer surface and defining an interior volume such that the glass body has an interior region extending into a thickness of the body from about 10nm below the inner surface of the body. The inner region can have a persistent layer uniformity such that the glass body is delamination resistant.

In another embodiment, a method of forming a delamination resistant glass container includes providing a feedstock formed from a delamination resistant glass composition. The raw material is formed into a glass article having a glass body extending between an inner surface and an outer surface and defining an interior volume such that the glass body has a surface area extending over the entire inner surface of the body. The surface region can have a depth extending from the inner surface of the body into a thickness of the body, and the surface region can have a persistent surface uniformity such that the body is resistant to delamination.

In another embodiment, a delamination resistant glass container may include a glass article having a body extending between an inner surface and an outer surface. The body may include a wall portion that transitions to a bottom portion via a root portion. The body may also include an inner region extending into a thickness of the body from about 10nm below the inner surface of the body, at least in the root portion of the body. The inner region may have a persistent layer uniformity such that the body is resistant to delamination.

In another embodiment, a delamination resistant glass container may include a glass article having a body extending between an inner surface and an outer surface, and the body including a wall portion transitioning to a bottom portion via a root portion. A surface region may extend over at least a surface of the root portion, and the surface region has a depth extending from the inner surface of the glass container into a thickness of the body. The surface region may have a persistent surface uniformity such that at least the root portion is resistant to delamination.

Additional features and advantages of the glass containers described herein will be set forth in the detailed description which follows, including the detailed description which follows, the claims, and the accompanying drawings, from which, in part, will be readily apparent to those skilled in the art or recognized by practicing the embodiments described herein.

It is to be understood that both the foregoing general description and the following detailed description present various embodiments, and are intended to provide an overview or framework for understanding the nature and character of the claimed subject matter. The accompanying drawings are included to provide a further understanding of the various embodiments, and are incorporated in and constitute a part of this specification. The drawings illustrate various embodiments described herein, and together with the embodiments serve to explain the principles and operations of the claimed subject matter.

Brief Description of Drawings

Fig. 1 schematically depicts a cross-sectional view of a glass container (specifically a glass vial) according to one or more embodiments described herein;

FIG. 2 schematically depicts a portion of a side wall of the glass container of FIG. 1;

FIG. 3 schematically depicts a portion of a side wall of the glass container of FIG. 1;

FIG. 4 graphically depicts partial pressure (y-axis) as a function of temperature (x-axis) for various species in a glass composition of a conventional type 1a borosilicate glass in equilibrium with a stoichiometric methane flame;

FIG. 5 graphically depicts partial pressure (y-axis) as a function of temperature (x-axis) for various species in a glass composition of a conventional type 1b borosilicate glass in equilibrium with a stoichiometric methane flame;

FIG. 6 graphically depicts partial pressures (y-axis) and temperatures (x-axis) of various species in a particular ZnO glass-containing glass composition in equilibrium with a stoichiometric methane flame;

FIG. 7 graphically depicts partial pressures (y-axis) of various species as a function of temperature (x-axis) in a glass composition of an exemplary alkali aluminosilicate glass in equilibrium with a stoichiometric methane flame;

FIG. 8A graphically depicts boron concentration (y-axis) as a function of depth from the inner surface of a root and sidewall portion of a glass vial formed from conventional type 1b borosilicate glass;

FIG. 8B graphically depicts sodium concentration (y-axis) as a function of depth from the inner surface of a root and sidewall portion of a glass vial formed from conventional type 1B borosilicate glass;

FIG. 9 graphically depicts sodium concentration (y-axis) as a function of depth from the interior surface of a root and sidewall portion of a glass vial formed from an exemplary boron-free alkali aluminosilicate glass;

FIG. 10 graphically depicts atomic ratio (y-axis) and distance from an interior surface (x-axis) of a glass vial formed from an exemplary alkali aluminosilicate glass exhibiting surface uniformity;

FIG. 11 graphically depicts atomic ratio (y-axis) and distance from the inner surface (x-axis) of a glass vial formed from conventional type 1b glass exhibiting surface uniformity;

FIG. 12 graphically depicts the elemental fraction of boron in the gas phase at 1500 ℃ (y-axis) and B added to a glass composition of the present invention in equilibrium with a stoichiometric methane flame₂O₃(x-axis);

FIG. 13A is an optical microscope image of a lamella developed during a delamination test of a glass vial formed from a glass composition susceptible to delamination;

FIG. 13B is an optical microscope image of a lamella developed during a delamination test of a glass vial formed from a delamination resistant glass composition;

FIG. 14A is an optical microscope image of a lamella developed during a delamination test of an ion exchanged glass vial formed from a glass composition susceptible to delamination; and

figure 14B is an optical microscope image of the flakes progressively produced during the delamination test of an ion-exchanged glass vial formed from the delamination resistant glass composition.

Description of the embodiments

Reference will now be made in detail to various embodiments of glass containers having improved resistance to delamination, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts. In one embodiment, a glass container having improved resistance to delamination may include a glass body extending between an inner surface and an outer surface, the glass body defining an interior volume. The glass body may be formed from an alkali aluminosilicate glass or an alkaline earth aluminosilicate glass. When the glass container is in an as-formed condition, in an interior region extending from an inner surface of the glass body to a depth of at least 100nm from the inner surface, a layer concentration of each constituent component in the glass composition may be greater than or equal to 90% and less than or equal to 110% of a total concentration of the same constituent component in the glass composition at a midpoint of a thickness of the glass body. The glass container and the nature of the glass container will be described in more detail herein with particular reference to the accompanying drawings.

In embodiments of the glass compositions described herein, the constituent components (e.g., SiO)₂、Al₂O₃、 B₂O₃Etc.) are specified as mole percent (mol%) on an oxide basis unless otherwise specified.

The term "substantially free of, when used to describe the concentration and/or absence of a particular constituent in a glass composition, means that the constituent is not intentionally added to the glass composition. However, the glass composition may contain a trace amount of the constituent as a contaminant or an impurity in an amount of less than 0.05 mol%.

The term "chemical durability" as used herein refers to the ability of the glass composition to resist degradation upon exposure to specified chemical conditions. Specifically, the chemical durability of the glass compositions described herein was evaluated according to 3 established material testing criteria: DIN 12116, dated 3.2001, entitled "Testing of glass-Resistance to attack by boiling aqueous hydrochloric acid-Method of Testing and classification (Testing of glass-Resistance to attack by a bailing aqueous solution of hydrochloric acid) -a Method of Testing and classification; ISO695:1991 entitled "Glass- -Resistance to attack by boiling an aqueous solution of mixed alkali metals- -Method of testing and Classification (Glass- -Resistance to attack by a binding aqueous solution of mixed alkali metals) - -Method of testing and Classification"; ISO 720:1985 entitled "Method for testing and classifying Glass- -hydrolysis resistance of Glass grains at121 ℃ (Glass- -hydrolysis resistance of Glass grains at121 ℃ C- -Method of test and classification)"; and ISO 719:1985 "Glass- -hydrolysis resistance of Glass particles at 98 ℃ Method of testing and classifying (Glass- -hydrolysis resistance of Glass grains at 98 ℃ C- -Method of test and classification)". Each criterion and the classifications within each criterion are described in further detail herein. Alternatively, the chemical durability of the Glass composition may be evaluated according to USP <660> titled "Surface Glass Test" and/or european pharmacopoeia 3.2.1 titled "Glass containers For Pharmaceutical Use" (which evaluates durability of Glass surfaces).

Glass containers or glass packages conventionally used for drug-containing compositions are generally formed from glass compositions known to exhibit chemical durability and low thermal expansion, such as alkali borosilicate glass. While alkali borosilicate glasses exhibit good chemical durability, container manufacturers have observed that silica-rich glass flakes are dispersed in the solution contained by the glass containers. This phenomenon is called delamination. Delamination can occur when, in particular, the solution has been stored in direct contact with the glass surface for a long period of time (months to years). Thus, glasses exhibiting good chemical durability may not necessarily be resistant to delamination.

Delamination refers to a phenomenon in which glass particles are released from the surface of the glass after a series of leaching, corrosion and/or weathering reactions. Generally, the glass particles are silica-rich glass flakes that originate from the interior surface of the package and result from the leaching of the modifier ions into the solution contained within the package. These flakes can be generally from about 1 nanometer (nm) to about 2 micrometers (μm) thick and have a width greater than about 50 μm. Since these flakes are composed primarily of silica, the flakes are generally not further degraded after being released from the glass surface.

It has been hypothesized heretofore that delamination is due to phase separation in the alkali borosilicate glass when the glass is exposed to elevated temperatures used to reshape the glass into a container shape.

However, it is presently believed that the delamination of the silica-rich glass flakes from the interior surface of the glass container is due to the compositional characteristics of the glass container in its as-formed condition. In particular, the high silica content of alkali borosilicate glasses can result in glasses having relatively high melting and forming temperatures. However, the alkali metal and borate components in the glass composition melt and/or evaporate at much lower temperatures. In particular, borate species in glass are highly volatile and can evaporate from the surface of the glass at the high temperatures required for glass forming and reforming.

Specifically, the glass raw materials are reformed into glass containers under a direct flame at high temperature. The high temperatures required at higher equipment speeds can cause the more volatile borate species to evaporate from portions of the glass surface. When such evaporation occurs within the interior volume of the glass container, the volatilized borate species may redeposit on other areas of the glass container surface, resulting in compositional non-uniformities at the glass container surface, particularly for near-surface areas of the glass container interior (i.e., those areas at or immediately adjacent to the interior surface of the glass container). For example, since one end of the glass tube is closed to form the bottom or bottom of the container, the borate species may evaporate from the bottom portion of the tube and redeposit elsewhere in the tube. Evaporation of material from the root and bottom portions of the vessel is particularly evident because these regions of the vessel are most extensively reshaped and therefore exposed to the highest temperatures. As a result, the regions of the vessel that are exposed to higher temperatures may have silica-rich surfaces. Other areas of the vessel that are amenable to boron deposition may have a boron-rich layer on the surface. Regions amenable to boron deposition, which are at temperatures above the annealing point of the glass composition but below the hottest temperature at which the glass is being reformed, may cause boron to be incorporated on the surface of the glass. The solution contained in the container may leach boron from the boron-rich layer. As the boron rich layer is leached from the glass, the retained high silica glass network (gel) will swell and stretch during hydration and eventually flake off the surface.

One conventional solution to delamination is to coat the interior surface of the glass container body with an inorganic coating, such as SiO₂. Such a coating may have a thickness of from about 100nm to 200nm and prevents delamination as the contents of the container contact the interior surface of the body. However, applying such coatings can be difficult and require additional manufacturing and/or inspection steps, thereby increasing the overall cost of container manufacture. Furthermore, if the contents of the container penetrate the coating to contact the inner surface of the body, for example via a discontinuity in the coating, the resulting delamination of the glass body may result in a portion of the coating detaching from the inner surface of the body.

The glass containers described herein have uniform compositional properties in the as-formed condition and thus exhibit improved resistance to delamination without the need for any additional processing.

Referring now to fig. 1, fig. 1 schematically illustrates a cross-sectional view of a delamination resistant glass container 100 for storing a pharmaceutical composition. The glass container 100 generally comprises a glass article having a glass body 102. The glass body 102 extends between an inner surface 104 and an outer surface 106 and generally encloses an interior volume 108. In the embodiment of the glass container 100 illustrated in fig. 1, the glass body 102 generally comprises a wall portion 110 and a bottom portion 112. The wall portion 110 and the bottom portion 112 may generally have a thickness in the range from about 0.5mm to about 3.0 mm. Wall portion 110 transitions into bottom portion 112 via root portion 114. Inner surface 104 and bottom portion 112 are uncoated (i.e., inner surface 104 and bottom portion 112 do not comprise any inorganic or organic coating, and thus, the contents stored in interior volume 108 of glass container 100 are in direct contact with the glass forming glass container 100. although glass container 100 is depicted in fig. 1 as having a particular shaped form (i.e., a vial), it should be appreciated that glass container 100 may have other shaped forms including, but not limited to, evacuated blood collection tubes, cartridges, syringes, ampoules, bottles, flasks, vials, tubes, beakers, and the like.

In some embodiments described herein, the glass body 102 is strengthened, for example, by ion exchange strengthening. Thus, it should be appreciated that the glass body 102 is formed from a glass composition that includes at least one alkali metal oxide component. The glass body 102 may have a compressive stress at the glass surface of greater than or equal to about 300 megapascals (MPa) or even greater than or equal to about 350 megapascals. In embodiments, the compressive stress may be greater than or equal to about 400 megapascals at the glass surface, or even greater than or equal to about 450 megapascals at the glass surface. In some embodiments, the compressive stress may be greater than or equal to about 500 mpa at the glass surface, or even greater than or equal to about 550 mpa at the glass surface. In other embodiments, the compressive stress may be greater than or equal to about 650 megapascals at the surface of the glass, or even greater than or equal to about 750 megapascals at the surface of the glass. The compressive stress in the glass body 102 typically extends to a depth of layer (DOL) of at least about 10 μm. In some embodiments, the glass body 102 may have a depth of layer greater than about 25 μm or even greater than about 50 μm. In some other embodiments, the depth of layer may be up to about 75 μm or even about 100 μm. The ion exchange strengthening may be performed in a molten salt bath maintained at a temperature of about 350 ℃ to about 500 ℃. To achieve the desired compressive stress, the glass container in the as-formed condition may be immersed in the salt bath for less than about 30 hours or even less than about 20 hours. In embodiments, the container may be immersed for less than about 15 hours or even less than about 12 hours. In other embodiments, the container may be immersed for less than about 10 hours. For example, in one embodiment, the glass container is immersed in 100% potassium nitrate (KNO) at about 450 ℃₃) Salt bath lasting about 5From hours to about 8 hours to achieve the desired depth of layer and compressive stress while maintaining the chemical durability of the glass composition.

Referring now to fig. 1 and 2, the glass containers described herein have a homogeneous composition throughout the thickness in each wall, root, and bottom portion of the glass body 102. In particular, fig. 2 schematically shows a partial cross-section of the wall portion 110 of the glass container 100. The glass body 102 of the glass container 100 has an interior region 120, the interior region 120 being about 10nm from below the interior surface 104 of the glass container 100 (indicated as D in FIG. 2)_LR1) Extending into the thickness of the wall portion 110 to a depth D from the inner surface 104 of the glass container_LR2To (3). Due to experimental artifacts, the internal region extending from about 10nm below the inner surface 104 will have a difference in composition from the first 5 to 10nm below the surface. At the beginning of the DSIMS analysis, the initial 5-10nm was not included in the analysis because of the following three considerations: the extrinsic carbon causes the sputtering rate of ions from the surface to be variable, the steady state charge established in part due to the variable sputtering rate, and the mixing of species when steady state sputtering conditions are established. As a result, the first two data points of the analysis were excluded, as illustrated in the example graphs of fig. 8 and 9. Thus, it should be appreciated that the inner region 120 has a thickness T_LRThickness T_LRIs equal to D_LR2-D_LR1. The glass composition within the interior region has a persistent layer uniformity that is associated with a thickness T of the interior region_LRI.e., sufficient to prevent delamination of the glass body after prolonged contact with the solution contained in the interior volume of the glass container. In some embodiments, the thickness T_LRIs at least about 100 nm. In some embodiments, the thickness T_LRAt least about 150 nm. In some other embodiments, the thickness T_LRAt least about 200nm or even about 250 nm. In some other embodiments, the thickness T_LRAt least about 300nm or even about 350 nm. In other embodiments, the thickness T_LRAt least about 500 nm. In some embodiments, the inner region 120 can extend to a thickness T of at least about 1 μm or even at least about 2 μm_LR。

Although the interior region was described above as extending into the thickness of the wall portion 110 from 10nm below the interior surface 104 of the glass container 100 to a depth D from the interior surface 104 of the glass container_LR2However, it should be understood that other embodiments are possible. For example, despite the experimental artifacts mentioned above, it is assumed that the interior region having this persistent layer uniformity may actually extend from the surface of the interior surface 104 of the glass container 100 into the thickness of the wall portion. Thus, in some embodiments, the thickness T_LRMay extend from the inner surface to a depth D_LR2. In these embodiments, the thickness T_LRAnd may be at least about 100 nm. In some embodiments, the thickness T_LRAt least about 150 nm. In some other embodiments, the thickness T_LRAt least about 200nm or even about 250 nm. In some other embodiments, the thickness T_LRAt least about 300nm or even about 350 nm. In other embodiments, the thickness T_LRAt least about 500 nm. In some embodiments, the inner region 120 can extend to a thickness T of at least about 1 μm or even at least about 2 μm_LR。

In the embodiments described herein, the term "persistent layer uniformity" means the constituent components of the glass composition (e.g., SiO) in the interior region₂、Al₂O₃、Na₂O, etc.) does not cause the glass body to delaminate after prolonged contact with the solution contained within the glass container at the same amount of difference in concentration of the same constituent components at the midpoint of the thickness of the glass body (i.e., at a point along the midpoint line MP that evenly bisects the glass body between the inner surface 104 and the outer surface 106). In the embodiments described herein, the persistent layer uniformity in the interior region of the glass body is such that the extreme value of the layer concentration (i.e., minimum or maximum) of each constituent component of the glass composition in the interior region 120 is greater than or equal to about 80% and less than or equal to about 120% of the extreme value of the layer concentration of the same constituent component at the midpoint of the thickness of the glass body when the glass container 100 is in the as-formed condition. In other embodiments, a durable layer in the interior region of the glass body when the glass container 100 is in the as-formed conditionThe homogeneity is such that the extreme value of the layer concentration of each constituent component of the glass composition in the interior region 120 is greater than or equal to about 90% and less than or equal to about 110% of the extreme value of the layer concentration of the same constituent component at the midpoint of the thickness of the glass body. In other embodiments, the persistent layer uniformity in the interior region of the glass body when the glass container 100 is in the as-formed condition is such that the extreme value of the layer concentration of each constituent component of the glass composition in the interior region 120 is greater than or equal to about 92% and less than or equal to about 108% of the extreme value of the layer concentration of the same constituent component at the midpoint of the thickness of the glass body. In some embodiments, the persistent layer uniformity excludes the presence of glass composition constituents in an amount less than about 2 mole percent.

As used herein, the term "as-formed conditions" refers to the composition of the glass container 100 before the glass container has been formed from glass feedstock but before the container is exposed to any additional processing steps (e.g., ion exchange strengthening, coating, ammonium sulfate treatment, etc.). In embodiments described herein, the layer concentrations of the constituent components in the glass composition are determined by collecting a sample of the composition through the thickness of the glass body in the region of interest using a dynamic secondary ion mass spectrometer. In the embodiments described herein, the composition profile is sampled from an area of the inner surface 104 of the glass body 102. The area sampled has a maximum of 1mm²The area of (a). This technique yields glass having a composition distribution of matter as a function of the depth of the sampling region from the inner surface of the glass body.

Forming a glass container with a persistent layer uniformity as described above may generally improve the delamination resistance of the glass container. In particular, providing an interior region that is compositionally uniform (i.e., the extrema in the concentrations of the constituent components in the interior region are within +/-20% of the same constituent components at the midpoint of the thickness of the glass body) can avoid localization of the concentrations of the constituent components of the readily leachable glass composition, thereby reducing glass particles lost from the interior surface of the glass container in the event these constituent components are leached from the glass surface.

As noted herein, the container in the as-formed condition is free of a coating (including inorganic and/or organic coatings applied to the inner surface of the glass body). Thus, it will be appreciated that the body of the glass container is formed from a substantially single composition extending from the inner surface of the body to a depth of at least 250nm or even at least 300 nm. The term "single composition" refers to the fact that the glass body portion extending from the inner surface into the depth of the body thickness by at least 250nm or even at least 300nm is a material of a single composition as compared to a coating material applied to another material of the same or different composition. For example, in some embodiments, the body of the container may be formed from a single glass composition. In another embodiment, the body of the container may be constructed of laminated glass such that the inner surface of the body has a single composition extending from the inner surface to a depth of at least 250nm or even at least 300 nm. The glass container may include an interior region extending from the interior surface or from 10nm below the interior surface to a depth of at least 100nm, as noted above. This inner region may have a persistent layer uniformity.

Referring now to fig. 1 and 3, the glass containers described herein may also have a uniform surface composition on the inner surface 104 of the glass body 102, including in the wall, root, and bottom portions. Fig. 3 schematically depicts a partial cross-section of the wall portion 110 of the glass container 100. The glass container 100 has a surface area 130 that extends over the entire inner surface of the glass container. Surface region 130 has a depth D_SRDepth D of_SRExtending into the thickness of the glass body from the inner surface 104 toward the outer surface of the glass container 100. Thus, it will be appreciated that surface region 130 has a thickness T_SRThickness T_SRIs equal to depth D_SR. In some embodiments, the surface region extends from the inner surface 104 of the glass container 100 to a depth D of at least about 10nm_SR. In some other embodiments, the surface region 130 may extend to a depth D of at least about 50nm_SR. In some other embodiments, the surface region 130 may extend to a depth D of about 10nm to about 50nm_SR. Thus, it should be appreciated that the surface region 130 extends to be shallower than the interior region 120Of the depth of (c). The glass composition of the surface region has a durable surface homogeneity which is associated with the depth D of the inner region_SRI.e., sufficient to prevent delamination of the glass body after prolonged contact with the solution contained in the interior volume of the glass container.

In the embodiments described herein, the term "durable surface uniformity" means the constituent components of the glass composition (e.g., SiO) at discrete points in the surface region₂、Al₂O₃、Na₂O, etc.) does not cause the glass body to delaminate after prolonged contact with the solution contained within the glass container. In the embodiments described herein, the persistent surface uniformity in the surface area when the glass container 100 is in the as-formed condition is such that for discrete points on the inner surface 104 of the glass container, the extremum in the surface concentration (i.e., the minimum or maximum value) of each constituent component at discrete points in the surface area 130 is greater than or equal to about 70% and less than or equal to about 130% of the extremum in the surface concentration of the same constituent component at any second discrete point in the surface area 130 on the inner surface 104 of the glass container 100. For example, fig. 3 depicts three discrete points (A, B and C) on the inner surface 104 of the wall portion 110. Each dot is spaced at least about 3mm from an adjacent dot. The extreme surface concentration value of each constituent component at point "a" in the surface region 130 is greater than or equal to about 70% and less than or equal to about 130% of the extreme surface concentration values of the same constituent component at points "B" and "C" in the surface region 130. When referring to the heel portion of the container, the discrete points may be approximately centered at the apex of the heel, and adjacent points located at least 3mm from the apex of the heel along the bottom portion of the container and along the wall portion of the container, the distance between the points being limited by the radius of the vial and the height of the sidewall (i.e., the point at which the sidewall transitions into the shoulder of the vial).

In some embodiments, the persistent surface uniformity in surface area when the glass container 100 is in an as-formed condition is such that at any discrete point in the surface area 130 on the inner surface 104 of the glass container 100, the extremum in surface concentration of each constituent component of the glass composition is greater than or equal to about 75% and less than or equal to about 125% of the extremum in surface concentration of the same constituent component at any second discrete point in the surface area 130 on the inner surface 104 of the glass container 100. In some other embodiments, the persistent surface uniformity in the surface area when the glass container 100 is in the as-formed condition is such that at any discrete point in the surface area 130 on the inner surface 104 of the glass container 100, the extremum in the surface concentration of each constituent component of the glass composition is greater than or equal to about 80% and less than or equal to about 120% of the extremum in the surface concentration of the same constituent component at any second discrete point in the surface area 130 on the inner surface 104 of the glass container 100. In other embodiments, the persistent surface uniformity in the surface area when the glass container 100 is in the as-formed condition is such that at any discrete point in the surface area 130 on the inner surface 104 of the glass container 100, the extremum in the surface concentration of each constituent component of the glass composition is greater than or equal to about 85% and less than or equal to about 115% of the extremum in the surface concentration of the same constituent component at any second discrete point in the surface area 130 on the inner surface 104 of the glass container 100. In the embodiments described herein, the surface concentration of the constituent components of the glass composition in the surface region is measured by photoelectron spectroscopy. In some embodiments, the durable surface uniformity in the surface region excludes the presence of glass composition constituents in an amount less than about 2 mole percent.

The surface concentration uniformity of the glass constituent components in the surface region 130 is generally indicative of the tendency of the glass composition to delaminate and shed glass particles from the inner surface 104 of the glass container 102. The glass composition has improved resistance to delamination when the glass composition has a durable surface uniformity in the surface region 130 (i.e., when the surface concentration extrema of the glass constituent component at discrete points in the surface region 130 on the inner surface 104 is within +/-30% of the surface concentration extrema of the same constituent component at any second discrete point in the surface region 130 on the inner surface 104).

It should now be appreciated that the glass containers described herein have a durable layer uniformity and/or a durable surface uniformity, each of which can improve the delamination resistance of the glass container. The persistent layer uniformity and/or persistent surface uniformity is present not only in the sidewall portions of the glass container, but also in the root and bottom portions of the glass container such that the glass container surfaces defining the interior volume are resistant to delamination.

As noted above, delamination may result in the release of silica-rich glass flakes into the solution contained within the glass container after prolonged contact with the solution. Thus, the delamination resistance can be characterized by the number of glass particles present in the solution contained within the glass container after contacting the solution under specified conditions. To evaluate the long term delamination resistance of glass containers, an accelerated delamination test was utilized. The test was performed on both ion-exchanged and non-ion-exchanged glass containers. The test involves washing the glass container at room temperature for 1 minute and de-heating the container at about 320 ℃ for 1 hour. Thereafter, a 20mM glycine solution in water (pH 10) was placed in a glass container, filled to 80-90% full, the glass container was closed and rapidly heated to 100 ℃ and then heated from 100 ℃ to 121 ℃ under a pressure of 2 atm at a temperature rising rate of 1 degree/min. The glass container and solution were held at this temperature for 60 minutes, cooled to room temperature at a rate of 0.5 degrees/minute, and the heating cycle and holding temperature were repeated. The glass container is then heated to 50 ℃ and held at elevated temperature for 10 or more days. After heating, the glass container is dropped from a distance of at least 18 "onto a solid surface, such as a laminated floor tile, to dislodge any flakes or particles that weakly adhere to the inner surface of the glass container. The distance of drop can be scaled appropriately to prevent larger size vials from breaking upon impact.

The solution contained in the glass container is then analyzed to determine the number of glass particles present per liter of solution. Specifically, the solution from the glass container was poured directly onto the center of a Millipore Isopore membrane filter (Millipore # ATTP02500 held in the assembly and having components # AP1002500 and # M000025a 0) attached to vacuum suction to draw 5 milliliters of the solution through the filter in 10-15 seconds. Thereafter, makeRinse with another 5ml of water to remove buffer residues from the filter medium. The particle flakes are then counted in reflectance mode by means of a Differential interference contrast microscope (DIC) as described in the optical microscope and digital imaging basis of Wiley-Liss, New York, Inc. (fundamental of light microscopy and digital imaging. New York: Wiley-Liss), page 153-. The field of view was set at about 1.5mm X1.5 mm and particles larger than 50 microns were counted manually. 9 such measurements were made at the center of each filter membrane in a 3X 3 pattern with no overlap between the images. In case a larger area of filter media is analyzed, the results can be normalized to the equivalent area (i.e., 20.25 square millimeters). Images collected from the light microscope were examined using the image analysis program (Media Cybernetic's ImagePro Plus version 6.1) to measure and count the number of glass sheets present. This is accomplished as follows: all appear to be against the background within the imageIs darkerThe features of (1) are highlighted by simple gray scale segmentation; then measuring the length, width, area and perimeter of all highlighted features with features having a length greater than 25 microns; any particles that were visibly non-glass were then removed from the data; the metrology data is then exported to a spreadsheet. Thereafter, all lengths greater than 25 microns and above background were extracted and measuredIs brighterThe features of (1); measuring the length, width, area, perimeter, and XY aspect ratio of all highlight features having a length greater than 25 microns; remove any particles that are apparently not glass from the data; and attaching the metrology data to previously exported data in the spreadsheet. The data in the spreadsheet is then sorted by feature length and divided into bins by size. The results reported are for features greater than 50 microns in length. Each of these groups was then counted and the count for each sample reported.

A minimum of 100ml of solution was tested. Thus, the solution from multiple small containers can be pooled to bring the total volume of solution to 100 mL. For containers having a volume greater than 10 milliliters, the testing of 10 containers formed from the same glass composition under the same processing conditions was repeated and the particle count results for the 10 containers were averaged to determine the average particle count. Alternatively, in the case of small containers, the test of 10 vials is repeated, each of which is analyzed and the particle counts of the vials are averaged to determine the average particle count for each vial. Averaging the particle counts of multiple containers accounts for potential variations in the delamination behavior of individual containers. Table 1 summarizes some non-limiting examples of sample volumes and container numbers used for testing:

table 1: table of exemplary test substances

It should be understood that the above test is intended to identify particles that have fallen off the interior wall of the glass container as a result of delamination, rather than foreign particles present in the container from the forming process or particles that have precipitated from the solution enclosed in the glass container as a result of reaction between the solution and the glass. Specifically, the difference between the delaminated particles and the tramp glass particles may be based on the aspect ratio of the particles (i.e., the ratio of the maximum length of the particles to the thickness of the particles, or the ratio of the maximum and minimum difference dimensions). Delamination produces flakes or sheets of particles that are irregular in shape and typically have a maximum length greater than about 50 μm, but often greater than about 200 μm. The thickness of the flakes is typically greater than about 100nm and may be as large as about 1 μm. Thus, the flakes typically have a minimum aspect ratio of greater than about 50. The aspect ratio may be greater than about 100, and sometimes may be greater than about 1000. In contrast, the impurity glass particles will generally have a low aspect ratio of less than about 3. Thus, the difference in particle to impurity particle resulting from delamination during microscopic observation can be based on aspect ratio. Other common non-glass particles include hair, fibers, metal particles, plastic particles, and other contaminants, and thus can be excluded during inspection. Verification of the results may be accomplished by evaluating the interior region of the container under test. It was observed that evidence of skin corrosion/pitting/flake removal was noted as described in Journal of Pharmaceutical Sciences (Journal of Pharmaceutical Sciences) 101(4) page 1378-1384, "Nondestructive examination of glass vial interior Surface Morphology with Differential Interference contrast microscope" (nondestructively Detection of glass Inner Surface Morphology with Differential Interference contrast microscope) ".

In the embodiments described herein, the number of particles present after the accelerated delamination test can be used to establish a delamination factor for the group of vials tested. In the embodiments described herein, glass container vials having an average of less than 10 glass particles per vial having a minimum length of about 50 μm and an aspect ratio greater than about 50 after accelerated delamination testing are considered to have a delamination factor of 10. In the embodiments described herein, an average of less than 9 glass container vials having a minimum length of about 50 μm and an aspect ratio greater than about 50 per vial after accelerated delamination testing is considered to have a delamination factor of 9. In the embodiments described herein, glass container vials having an average of less than 8 glass particles per vial having a minimum length of about 50 μm and an aspect ratio greater than about 50 after accelerated delamination testing are considered to have a delamination factor of 8. In the embodiments described herein, an average of less than 7 glass container vials per vial having a minimum length of about 50 μm and an aspect ratio greater than about 50 after the accelerated delamination test are considered to have a delamination factor of 7. In the embodiments described herein, an average of less than 6 glass container vials per vial having a minimum length of about 50 μm and an aspect ratio greater than about 50 after accelerated delamination testing is considered to have a delamination factor of 6. In the embodiments described herein, an average of less than 5 glass container vials per vial having a minimum length of about 50 μm and an aspect ratio greater than about 50 after accelerated delamination testing is considered to have a delamination factor of 5. In the embodiments described herein, an average of less than 4 glass container vials having a minimum length of about 50 μm and an aspect ratio greater than about 50 per vial after accelerated delamination testing is considered to have a delamination factor of 4. In the embodiments described herein, an average of less than 3 glass container vials having a minimum length of about 50 μm and an aspect ratio greater than about 50 per vial after accelerated delamination testing is considered to have a delamination factor of 3. In the embodiments described herein, an average of less than 2 glass container vials per vial having a minimum length of about 50 μm and an aspect ratio greater than about 50 after accelerated delamination testing is considered to have a delamination factor of 2. In the embodiments described herein, an average of less than 1 glass container vial having a minimum length of about 50 μm and an aspect ratio greater than about 50 per vial after accelerated delamination testing is considered to have a delamination factor of 1. In the embodiments described herein, an average of less than 0 glass container vials per vial having a minimum length of about 50 μm and an aspect ratio greater than about 50 after the accelerated delamination test are considered to have a delamination factor of 0. Thus, it should be appreciated that the smaller the delamination factor, the better the delamination resistance of the glass container. In the embodiments described herein, the glass container has a delamination factor of 10 or less (i.e., a delamination factor of 3, 2, 1, or 0).

Glass containers having the above-described characteristics (i.e., uniform composition across the inner surface and through the thickness and resistance to delamination) are obtained by forming the glass containers from glass compositions whose constituent components form a species having a lower vapor pressure (i.e., low volatiles) at the temperature required to reshape the glass container from glass feedstock into the desired container shape. Because these constituent components form species with lower vapor pressure at the reforming temperature, the constituent components are less likely to volatilize and evaporate from the glass surface, thereby forming a glass container with a uniform surface composition on the interior of the glass container and through the thickness of the glass container.

Certain constituent components of the glass composition may be sufficiently volatile at the glass forming and reforming temperatures, which in turn may lead to compositional non-uniformities and subsequent delamination. The forming and reforming temperatures of the glass composition are generally temperatures corresponding to the glass composition having a viscosity in a range of about 200 poise (poise) to about 100 kpoise. Thus, in some embodiments, the glass composition forming the glass container does not form significant volatilization (i.e., form an equilibrium partial pressure greater than about 10) at a temperature corresponding to a viscosity in the range of about 200 poise to about 100 kpoise^-3Gaseous phase at atmospheric pressureMaterial) of the substance. In some embodiments, the glass composition forming the glass container is free of constituents that significantly volatilize at a temperature corresponding to a viscosity in a range from about 1 kpoise to about 50 kpoise. In some other embodiments, the glass composition forming the glass container is free of constituents that significantly volatilize at a temperature corresponding to a viscosity in a range from about 1 kpoise to about 20 kpoise. In some other embodiments, the glass composition forming the glass container is free of constituents that significantly volatilize at a temperature corresponding to a viscosity in a range from about 1 kilo-poise to about 10 kilo-poise. Without wishing to be bound by theory, compounds that are significantly volatile under these conditions include, but are not limited to, boron compounds, phosphorus compounds, zinc compounds, fluorine compounds, chlorine compounds, tin compounds, sodium and sodium compounds.

In the embodiments described herein, the glass container is generally formed from an alkali aluminosilicate glass composition or an alkaline earth aluminosilicate glass composition. As noted above, boron-containing species in glass are highly volatile at the elevated temperatures used for glass forming and reforming, thus leading to delamination of the resulting glass container. In addition, boron-containing glass compositions are also susceptible to phase separation, as described above. Thus, in the embodiments described herein, the boron concentration in the glass composition forming the glass container is limited to reduce delamination and phase separation. In some embodiments, the glass composition forming the glass container comprises less than or equal to about 1.0 mole percent of boron oxide and/or boron containing compounds, including but not limited to B₂O₃. In some of these embodiments, the concentration of boron oxide and/or boron-containing compound in the glass composition may be less than or equal to about 0.5 mol%, less than or equal to about 0.4 mol%, or even less than or equal to about 0.3 mol%. In some of these embodiments, the concentration of boron oxide and/or boron-containing compound in the glass composition may be less than or equal to about 0.2 mol% or even less than or equal to about 0.1 mol%. In some other embodiments, the glass composition is substantially free of boron and boron-containing compounds.

Phosphorus (like boron)As such) generally form in the glass composition a species that is highly volatile at the elevated temperatures used for glass forming and reforming. Thus, phosphorus in the glass composition can cause compositional non-uniformities in the finished glass container, which in turn can lead to delamination. Thus, in embodiments described herein, phosphorus and phosphorus-containing compounds (e.g., P) are limited in the glass composition forming the glass container₂O₅Etc.) to reduce delamination. In some embodiments, the glass composition from which the glass container is made comprises less than or equal to about 0.3 mole percent of phosphorus oxide and/or phosphorus-containing compound. In some of these embodiments, the concentration of phosphorus oxide and/or phosphorus-containing compound in the glass composition may be less than or equal to about 0.2 mol% or even less than or equal to about 0.1 mol%. In some other embodiments, the glass composition is substantially free of phosphorus and phosphorus-containing compounds.

Zinc (like boron and phosphorus) typically forms a highly volatile species in the glass composition at the elevated temperatures used for glass forming and reforming. Thus, the zinc in the glass composition can cause compositional non-uniformities in the finished glass container, which in turn can lead to delamination. Thus, in the embodiments described herein, the concentration of zinc and zinc-containing compounds (e.g., ZnO, etc.) in the glass composition forming the glass container is limited to reduce delamination. In some embodiments, the glass composition from which the glass container is made comprises less than or equal to about 0.5 mole% zinc oxide and/or zinc-containing compound. In some other embodiments, the glass composition from which the glass container is made comprises less than or equal to about 0.3 mole% zinc oxide and/or zinc-containing compound. In some of these embodiments, the concentration of zinc oxide or zinc-containing compound in the glass composition can be less than or equal to about 0.2 mol% or even less than or equal to about 0.1 mol%. In some other embodiments, the glass composition is substantially free of zinc and zinc-containing compounds.

Lead and bismuth also form species in the glass composition that are highly volatile at the elevated temperatures used for glass forming and reforming. Thus, in the embodiments described herein, the concentration of lead, bismuth, lead-containing compounds, and bismuth-containing compounds in the glass composition forming the glass container is limited to reduce delamination. In some embodiments, each of the lead oxide, bismuth oxide, lead-containing compound, and/or bismuth-containing compound is present in the glass composition at a concentration of less than or equal to about 0.3 mole percent. In some of these embodiments, each of the lead oxide, bismuth oxide, lead-containing compound, and/or bismuth-containing compound is present in the glass composition at a concentration of less than or equal to about 0.2 mol% or even at a concentration of less than about 0.1 mol%. In some other embodiments, the glass composition is substantially free of lead and/or bismuth and lead and/or bismuth containing compounds.

Substances containing chlorine, fluorine and tin oxides are also highly volatile at elevated temperatures used for glass forming and reforming. Thus, in the embodiments described herein, chlorine, fluorine, and tin oxides and tin-, chlorine-, or fluorine-containing compounds are present in the glass composition at concentrations that do not affect the delamination resistance of the resulting glass. Specifically, the chlorine, fluorine, and tin oxides and the tin, chlorine, or fluorine-containing compounds are present in the glass composition forming the glass container at a concentration of less than or equal to about 0.5 mole percent or even less than or equal to about 0.3 mole percent. In some embodiments, the glass composition is substantially free of tin, chlorine, and fluorine and compounds containing tin, chlorine, or fluorine.

When the glass container is in the as-formed condition, the glass compositions forming the container are not phase separated. The term "phase separated" as used herein refers to the separation of a glass composition into separate phases, with each phase having different compositional characteristics. For example, alkali borosilicate glasses are generally known to phase separate into a boron-rich phase and a silica-rich phase at elevated temperatures (e.g., forming and reforming temperatures). In the embodiments described herein, the concentration of boron oxide in the glass composition is sufficiently low (i.e., less than or equal to about 0.3 mole percent) that the glass composition does not phase separate when the glass container is in the as-formed condition.

The chemical durability of the glass is generally not reduced by the ion exchange process, and thus, unless otherwise indicated, reference is made toAnd the chemical durability of the glass is both before and after ion exchange. The glass composition forming the glass container is chemically durable and resistant to degradation as determined by ISO 720 standards. The ISO 720 standard measures the resistance of glass to degradation in distilled water (i.e., the resistance of glass to hydrolysis). Briefly, the ISO 720 standard protocol utilizes crushed glass grains and contacts the crushed glass grains with 18M Ω water for 30 minutes under autoclave conditions (121 ℃, 2 atm). The solution was then colorimetrically titrated to neutral pH with dilute hydrochloric acid. The amount of HCl required for titration to a neutral solution is then converted to equivalent Na extracted from the glass₂O, and reported in micrograms (μ g) of glass, with smaller values indicating higher durability. The ISO 720 standard is divided into various types. Type HGA1 indicates extraction of sodium oxide (Na) equivalent to up to 62 micrograms (. mu.g)₂O); type HGA2 indicates extraction of Na equivalent to more than 62. mu.g and up to 527. mu.g₂O; type HGA3 indicates extraction of Na equivalent to more than 527. mu.g and up to 930. mu.g₂And O. The glass compositions described herein have a resistance to hydrolysis of ISO 720 type HGA2, and some embodiments have a resistance to hydrolysis of type HGA 1.

The glass composition forming the glass container is also chemically durable and resistant to degradation as determined by ISO 719 standard. The ISO 719 standard measures the degradation resistance of glass in distilled water (i.e., the hydrolysis resistance of glass). Briefly, the ISO 719 standard protocol utilizes crushed glass grains and contacts the crushed glass grains with 18M Ω water at 2 atmospheres and 98 ℃ for 60 minutes. The solution was then colorimetrically titrated to neutral pH with dilute hydrochloric acid. The amount of HCl required for titration to a neutral solution is then converted to equivalent Na extracted from the glass₂O, and reported in micrograms (μ g) of glass, with smaller values indicating higher durability. The ISO 719 standard is divided into various types. Type HGB1 shows extraction of Na equivalent to up to 31. mu.g₂O; type HGB2 indicates extraction of Na equivalent to more than 31. mu.g and up to 62. mu.g₂O; type HGB3 indicates extraction of Na equivalent to more than 62. mu.g and up to 264. mu.g₂O; type HGB4 indicates extraction of Na equivalent to more than 264. mu.g and up to 620. mu.g₂O; and type HGB5 indicates that the extraction is equivalent to more than 620 μ g and up to 1085 μ g of Na₂And O. The glass compositions described herein have a resistance to hydrolysis of ISO 719 type HGB2, and some embodiments have a resistance to hydrolysis of type HGB 1.

The glass containers described herein have a type 1 chemical durability for the USP <660> test and/or the European pharmacopoeia (European pharmacopoeia) 3.2.1 test. As noted above, the USP <660> and european pharmacopoeia 3.2.1 tests are performed on intact glass containers, rather than broken glass grains, and thus, the USP <660> and european pharmacopoeia 3.2.1 tests can be used to directly evaluate the chemical durability of the inner surface of glass containers.

It should be understood that a glass composition or glass article having the specified "or better" category, when referred to the above-referenced categories under ISO 719 and ISO 720, indicates that the performance of the glass composition is as good or better than the specified category. For example, a glass article having an "HGB 2" or better hydrolysis resistance of ISO 719 may have a hydrolysis resistance of class HGB2 or HGB1 of ISO 719.

Delamination resistant glass containers are formed by providing a feedstock formed from a delamination resistant glass composition (e.g., glass tube, glass sheet, etc.) and forming the delamination resistant glass composition into a glass container using conventional forming techniques such that the glass container has at least one of a durable surface uniformity, a durable layer uniformity, a delamination factor of 1, and/or combinations thereof.

In the embodiments described herein, the glass container is formed from a glass composition having a temperature at which the viscosity of the glass is 1000 poise and which is less than or equal to about 1700 ℃ (i.e., a temperature of 1000 poise), which facilitates reshaping the glass into its final container shape without the need for temperatures that are too high to further promote volatilization of certain substances in the glass. Higher silicon dioxide (SiO) as further described herein₂) The concentration may improve the chemical durability of the glass but reduce the formability of the glass. Thus, high SiO₂The glass composition may be formulated with ingredients that reduce the viscosity of the glass while maintaining chemical durability. In some casesIn embodiments, the 1000 poise temperature may be less than or equal to about 1675 ℃ or even less than or equal to about 1650 ℃. In some other embodiments, the 1000 poise temperature may be less than or equal to about 1625 ℃ or even less than or equal to about 1600 ℃.

In a first exemplary embodiment, the Glass container is formed from a delamination resistant Glass composition such as an alkali aluminosilicate Glass composition as described in U.S. patent application No. 13/660,450 (attorney docket No. SP11-240) filed on 25.10.2012 And entitled "Glass composition With Improved Chemical And mechanical durability," which is incorporated herein by reference in its entirety. This first exemplary glass composition generally includes SiO₂、Al₂O₃At least one alkaline earth metal oxide and one or more alkali metal oxides (e.g., Na)₂O and/or K₂O) in combination. In some embodiments of this first exemplary glass composition, the glass composition may be boron-free and boron-containing compound-free. The combination of these ingredients makes the glass composition resistant to chemical degradation and also suitable for chemical strengthening by ion exchange. In some embodiments, this exemplary glass composition may further comprise minor amounts of one or more additional oxides, such as tin oxide (SnO)₂) Zirconium oxide (ZrO)₂) Zinc oxide (ZnO), titanium dioxide (TiO)₂) Arsenic trioxide (As)₂O₃) And the like. These ingredients may be added as fining agents and/or to further enhance the chemical durability of the glass composition.

In this first exemplary glass composition embodiment, silica is the largest constituent of the composition and, therefore, is the predominant component of the glass network produced. Silica enhances the chemical durability of the glass, particularly the resistance of the glass composition to decomposition in acid and the resistance of the glass composition to decomposition in water. Therefore, high silica concentrations are generally required. In the embodiments described herein, the glass composition typically comprises a large amount(ii) less than or equal to about 67 mole percent and less than or equal to about 80 mole percent or even less than or equal to about 78 mole percent silica. In some embodiments, the amount of silica in the glass composition may be greater than about 68 mol%, greater than about 69 mol%, or even greater than about 70 mol%. In some other embodiments, the SiO in the glass composition₂The amount of (a) may be greater than about 72 mole%, greater than about 73 mole%, or even greater than about 74 mole%. For example, in some embodiments, the glass composition may include from about 68 mol% to about 80 mol% or even to about 78 mol% SiO₂. In some other embodiments, the glass composition may include from about 69 mol% to about 80 mol% or even to about 78 mol% SiO₂. In some other embodiments, the glass composition may include from about 70 mol% to about 80 mol% or even to about 78 mol% SiO₂. In other embodiments, the glass composition comprises silica in an amount greater than or equal to about 70 mol.% and less than or equal to about 78 mol.%. In some embodiments, SiO that may be present in the glass composition₂The amount is from about 72 mol% to about 78 mol%. In some other embodiments, SiO may be present in the glass composition₂The amount is from about 73 mol% to about 78 mol%. In other embodiments, SiO may be present in the glass composition₂The amount is from about 74 mol% to about 78 mol%. In other embodiments, SiO may be present in the glass composition₂The amount is from about 70 mol% to about 76 mol%.

Embodiments of this first exemplary glass composition may further include aluminum oxide (Al)₂O₃)。Al₂O₃Together with alkali metal oxides (e.g., Na) present in the glass composition₂O, etc.) can improve the chemical durability and sensitivity of the glass to ion exchange strengthening. In embodiments described herein, Al present in the glass composition₂O₃X mol.% and the alkali metal oxide present in the glass composition is Y mol.%. The ratio of Y to X in the glass compositions described herein is greater than1 to promote melting behavior and the above-mentioned sensitivity to ion exchange enhancement. Specifically, the diffusivity, or diffusivity, D, of the glass composition is related to the rate at which alkali metal ions penetrate (or leach) into the glass surface during ion exchange. Glasses with Y: X ratios greater than about 0.9 or even greater than about 1 have greater diffusivity than glasses with Y: X ratios less than about 0.9. For a given ion exchange time and ion exchange temperature, glasses containing alkali metal ions with greater diffusivity may achieve greater depth of layer than glasses containing alkali metal ions with lesser diffusivity. In addition, as the ratio of Y to X increases, the strain point, annealing point, and softening point of the glass decrease, making the glass easier to shape. Further, for a given ion exchange time and ion exchange temperature, it has been found that the compressive stress induced in a glass having a Y: X ratio greater than about 0.9 and less than or equal to about 2 is generally greater than the compressive stress generated in a glass having a Y: X ratio less than about 0.9 or greater than about 2. Thus, in some embodiments, the Y: X ratio is greater than about 0.9 or even greater than about 1. In some embodiments, the ratio of Y to X is greater than about 0.9 or even greater than about 1 and less than or equal to about 2. In other embodiments, the ratio of Y to X can be greater than or equal to about 1.3 and less than or equal to about 2.0 to maximize the amount of compressive stress induced in the glass at a specified ion exchange time and a specified ion exchange temperature.

However, if Al is present in the glass composition₂O₃Too high an amount may reduce the acid erosion resistance of the glass composition. Thus, the glass compositions described herein generally include greater than or equal to about 2 mol.% and less than or equal to about 10 mol.% Al₂O₃And (4) content. In some embodiments, Al in the glass composition₂O₃In an amount greater than or equal to about 4 mol% and less than or equal to about 8 mol%. In some other embodiments, the Al in the glass composition₂O₃In an amount greater than or equal to about 5 mole% to less than or equal to about 7 mole%. In some other embodiments, the Al in the glass composition₂O₃In an amount greater than or equal to about 6 mole% to less than or equal to about 8 mole%. In other placesIn an embodiment of (1), Al in the glass composition₂O₃In an amount greater than or equal to about 5 mole% to less than or equal to about 6 mole%.

The glass composition of this first exemplary embodiment may also include one or more alkali metal oxides, such as Na₂O and/or K₂And O. The alkali metal oxide promotes ion exchangeability of the glass composition and thus promotes chemical strengthening of the glass. The alkali metal oxide may include Na₂O and K₂One or more of O. The alkali metal oxide is generally present in the glass composition at a total concentration of Y mole percent. In some embodiments described herein, Y may be greater than about 2 mol% and less than or equal to about 18 mol%. In some other embodiments, Y may be greater than about 8 mole%, greater than about 9 mole%, greater than about 10 mole%, or even greater than about 11 mole%. For example, in some embodiments described herein, Y is greater than or equal to about 8 mol% and less than or equal to about 18 mol%. In other embodiments, Y may be greater than or equal to about 9 mol% and less than or equal to about 14 mol%.

The ion exchangeability of the glass composition in this first exemplary embodiment is mainly due to the alkali metal oxide Na originally present in the glass composition before the ion exchange₂The content of O is added to the glass composition. Thus, in embodiments of the glass compositions described herein, the alkali metal oxide present in the glass composition comprises at least Na₂And O. In particular, to achieve the desired compressive strength and depth of layer in the glass composition after ion exchange strengthening, the glass composition includes Na₂The amount of O is from about 2 mol% to about 15 mol%. In some embodiments, the glass composition comprises at least about 8 mol% Na₂And O. For example, Na₂The concentration of O may be greater than about 9 mole%, greater than about 10 mole%, or even greater than about 11 mole%. In some embodiments, Na₂The concentration of O may be greater than or equal to about 9 mole percent or even greater than or equal to about 10 mole percent. For example, in some embodiments, theThe glass composition may include Na₂The O content is greater than or equal to about 9 mole percent and less than or equal to about 15 mole percent or even greater than or equal to about 9 mole percent and less than or equal to about 13 mole percent.

As indicated above, the alkali metal oxide in the first exemplary glass composition may further include K₂And O. When K is₂As the amount of O present in the first example glass composition increases, the compressive stress achievable via ion exchange decreases as a result of the potassium and sodium ion exchange. Therefore, it is desirable to limit the K present in the glass composition₂And (4) the content of O. In some embodiments, K₂The amount of O is greater than or equal to 0 mole percent and less than or equal to about 3 mole percent. In some embodiments, K₂The amount of O is less than or equal to about 2 mole percent or even less than or equal to about 1.0 mole percent. In the glass composition comprising K₂In embodiments of O, K may be present₂The concentration of O is greater than or equal to about 0.01 mole% and less than or equal to about 3.0 mole% or even greater than or equal to about 0.01 mole% and less than or equal to about 2.0 mole%. In some embodiments, K is present in the glass composition₂The O content is greater than or equal to about 0.01 mole percent and less than or equal to about 1.0 mole percent. Thus, it will be appreciated that K₂O need not be present in the glass composition. However, when K is included in the glass composition₂When O is, K₂The amount of O is typically less than about 3 mole%.

In embodiments described herein, the glass composition may include at least one alkaline earth oxide constituent. The alkaline earth metal oxides present in the first exemplary glass composition may improve the meltability of the glass batch material and increase the chemical durability of the glass composition. In the glass compositions described herein, the total mole% of alkaline earth metal oxides present in the glass composition is generally less than the total mole% of alkali metal oxides present in the glass composition to improve the ion exchangeability of the glass composition. In the embodiments described herein, the glass composition generally includes from about 3 mol% to about 13 mol% alkaline earth oxide. In some of these embodiments, the alkaline earth oxide may be present in the glass composition in an amount from about 4 mol% to about 8 mol%, or even from about 4 mol% to about 7 mol%.

The alkaline earth metal oxides in this first exemplary glass composition may include MgO, CaO, SrO, BaO, or combinations thereof. For example, in embodiments of the first exemplary glass composition described herein, the alkaline earth oxide comprises magnesium oxide (MgO). The MgO is present in the glass composition in an amount greater than or equal to about 3 mol.% and less than or equal to about 8 mol.%. In some embodiments, MgO is present in the glass composition in an amount greater than or equal to about 3 mol% and less than or equal to about 7 mol%, or even greater than or equal to about 4 mol% and less than or equal to about 7 mol%.

In some embodiments of the first exemplary glass composition, the alkaline earth metal oxide may further include calcium oxide (CaO). In these embodiments, the CaO is present in the glass composition in an amount from about 0 mol.% to less than or equal to about 6 mol.%. For example, CaO may be present in the glass composition in an amount less than or equal to about 5 mol%, less than or equal to about 4 mol%, less than or equal to about 3 mol%, or even less than or equal to about 2 mol%. In some of these embodiments, the CaO is present in the glass composition in an amount greater than or equal to about 0.1 mol.% and less than or equal to about 1.0 mol.%. For example, CaO may be present in the glass composition in an amount greater than or equal to about 0.2 mol% and less than or equal to about 0.7 mol%, or even in an amount greater than or equal to about 0.3 mol% and less than or equal to about 0.6 mol%.

In this first exemplary glass composition embodiment, the glass composition is generally MgO-rich (i.e., the concentration of MgO in the glass composition is greater than the concentration of other alkaline earth oxides in the glass composition, including but not limited to CaO). Forming the glass composition such that the glass composition is MgO-rich can improve the hydrolysis resistance of the resulting glass, particularly after ion-exchange strengthening. Furthermore, MgO-rich glass compositions generally exhibit improved ion exchange properties relative to glass compositions rich in other alkaline earth oxides. In particular, glasses formed from MgO-rich glass compositions generally have a greater diffusivity for alkali metals than glass compositions that are rich in other alkaline earth oxides (e.g., CaO). The greater the diffusivity of the alkali metal, the greater the depth of layer that can be formed in the glass. The magnesia-rich glass compositions are also capable of achieving higher compressive stresses in the surface of the glass than glass compositions rich in other alkaline earth oxides (e.g., CaO). Furthermore, it is generally understood that the maximum compressive stress achieved at the surface of the glass may decrease over time as the ion exchange treatment is performed and the alkali metal ions penetrate deeper into the glass. However, glasses formed from glass compositions rich in magnesia exhibit less reduction in compressive stress than glasses formed from glass compositions rich in calcium oxide or other alkaline earth oxides (i.e., magnesia-deficient glasses). Thus, the magnesia-rich glass composition enables the glass to have a greater compressive stress and a greater depth of layer at the surface than other alkaline earth oxide-rich glasses.

In order to fully realize the benefits of MgO in the glass compositions described herein, it has been determined that the ratio of CaO concentration to the sum of CaO concentration and MgO concentration (both in molar percent) (i.e., (CaO/(CaO + MgO)). specifically, (CaO/(CaO + MgO)) should be less than or equal to about 0.5. in some embodiments, (CaO/(CaO + MgO)) is less than or equal to about 0.3 or even less than or equal to about 0.2. in some other embodiments, (CaO/(CaO + MgO)) may even be less than or equal to about 0.1.

The first exemplary glass composition may optionally further comprise one or more fining agents, such as tin oxide (SnO)₂) Arsenic trioxide (As)₂O₃) And/or Cl^-(from NaCl, etc.). When present in the glass composition, the fining agent may be present in an amount less than or equal to about 0.5 mol%. For example, in some embodiments, the glass composition may include SnO as a fining agent₂. In these embodiments, SnO may be present in the glass composition₂In an amount greater than about 0 mole% and less than or equal to about 0.5 mole%, or SnO₂Even in amounts less than or equal to about 0.30 mole percent.

Boron trioxide (B)₂O₃) Is a fluxing agent that can be used to melt B at a given temperature (e.g., strain, anneal, and softening temperatures)₂O₃Are added to the glass composition to reduce viscosity and thereby improve the formability of the glass. However, it has been found that the addition of boron significantly reduces the diffusivity of sodium and potassium ions in the glass composition, thereby adversely affecting the ion exchange properties of the resulting glass. In particular, it has been found that the addition of boron significantly increases the time required to achieve a given depth of layer relative to a boron-free glass composition. Thus, in some embodiments described herein, the amount of boron added to the glass composition is minimized to improve the ion exchange properties of the glass composition.

For example, it has been determined that B can be controlled by₂O₃Concentration versus total alkali metal oxide concentration (i.e., R)₂O, wherein R is an alkali metal) and alumina (i.e., B)₂O₃(mol%)/(R)₂O (mol%) -Al₂O₃(mole%)) to mitigate the effect of boron on the ion exchange properties of the glass composition. In particular, it has been determined that when B₂O₃/(R₂O-Al₂O₃) When the ratio of (a) to (b) is greater than or equal to about 0 and less than about 0.3 or even less than about 0.2, the diffusivity of the alkali metal oxide in the glass composition is not diminished, and thus, the ion exchange properties of the glass composition are maintained. Thus, in some embodiments, B₂O₃/(R₂O-Al₂O₃) Is greater than 0 and less than or equal to about 0.3. In some of these embodiments, B₂O₃/(R₂O-Al₂O₃) Is greater than 0 and less than or equal to about 0.2. In some embodiments, B₂O₃/(R₂O-Al₂O₃) Is greater than 0 and less than or equal to about 0.15 or even less than or equal to about 0.1. In some other embodiments, B₂O₃/(R₂O-Al₂O₃) The ratio of (d) may be greater than 0 and less than or equal to about 0.05. B is to be₂O₃/(R₂O-Al₂O₃) Maintaining a ratio of (A) less than or equal to about 0.3 or even less than or equal to about 0.2 allows for the inclusion of B₂O₃To lower the strain point, annealing point and softening point of the glass composition, and is free of B₂O₃Adversely affecting the ion exchange properties of the glass.

In embodiments described herein, B in the glass composition₂O₃The concentration is typically less than or equal to about 1 mole%. For example, the presence of B in the glass composition₂O₃In the embodiment (B)₂O₃The concentration of (c) may be greater than about 0.01 mole% and less than or equal to about 1 mole%. In some of these embodiments, B₂O₃The concentration of (a) may be greater than about 0.01 mole% and less than or equal to about 0.9 mole%. In some embodiments, B₂O₃May be present in an amount greater than or equal to about 0.01 mole percent and less than or equal to about 0.8 mole percent, or even less than or equal to about 7 mole percent. Or, B₂O₃May be present in an amount greater than or equal to about 0.01 mole% and less than or equal to about 0.6 mole%, B₂O₃May be present in an amount greater than or equal to about 0.01 mole% and less than or equal to about 0.5 mole% or even B₂O₃May be present in an amount greater than or equal to about 0.01 mole percent and less than or equal to about 0.4 mole percent. In some of these embodiments, B₂O₃The concentration of (a) can be greater than or equal to about 0.01 mole% and less than or equal to about 0.3 mole%.

Although in some embodiments B in the glass composition will be₂O₃The concentration is minimized to improve the forming properties of the glass and not to reduce the ion exchange properties of the glass, but in some other embodiments, the glass composition is boron-free and boron-free compounds (e.g., B)₂O₃) In (1). In particular, it has been determined that forming glass compositions free of boron or boron compounds can improve the ion exchangeability of the glass compositions by reducing the process time and/or temperature required to achieve a particular compressive stress value and/or depth of layer.

In some embodiments of the first exemplary glass composition, the glass composition is phosphorus-free and free of phosphorus-containing compounds (including, but not limited to, P)₂O₅). In particular, it has been determined that formulating glass compositions that are free of phosphorus or phosphorous compounds can improve the chemical durability of the glass composition.

Except for SiO₂、Al₂O₃The glass compositions of the first exemplary glass composition may optionally further comprise one or more fining agents, such as SnO₂、 As₂O₃And/or Cl^-(from NaCl, etc.). When present in the glass composition, the fining agent may be present in an amount less than or equal to about 0.5 mol%, or even less than or equal to about 0.4 mol%. For example, in some embodiments, the glass composition may include SnO as a fining agent₂. In these embodiments, the SnO present in the glass composition₂The amount can be greater than about 0 mole% and less than or equal to about 0.5 mole%, or even SnO₂The amount can be greater than or equal to about 0.01 mole% and less than or equal to about 0.30 mole%.

In addition, embodiments of the first exemplary glass composition may include one or more additional metal oxides to further improve the chemical durability of the glass composition. For example, the glass composition may further include zinc oxide (ZnO), titanium dioxide (TiO)₂) Or zirconium oxide (ZrO)₂) Each of which further improves the chemical resistance of the glass composition. In these embodiments, the additional metal oxide may be present in an amount greater than or equal to about 0 mol% and less than or equal to about 2 mol%. For example, when the additional metal oxide is ZnO, the ZnO may be present in an amount less than or equal toAt about 0.5 mole%. When the additional metal oxide is ZrO₂Or TiO₂Of (i) ZrO₂Or TiO₂May be present in an amount less than or equal to about 1 mole%.

In light of the above, it should be appreciated that the first exemplary glass composition may include SiO in a concentration greater than about 74 mol-%₂(ii) a An alkaline earth metal oxide comprising MgO and CaO, wherein CaO is present in an amount greater than or equal to about 0.1 mol% and less than or equal to about 1.0 mol%, and the ratio (CaO (mol%)/(CaO (mol%) + MgO (mol%))) is less than or equal to 0.5; and Y mol% of an alkali metal oxide, wherein the alkali metal oxide contains Na₂The O content is greater than about 8 mole percent, wherein the glass composition is free of boron and boron compounds.

In another embodiment, the first exemplary glass composition may include about 74 mol% to about 78 mol% SiO₂(ii) a About 4 mol% to about 8 mol% of an alkaline earth oxide, wherein the alkaline earth oxide comprises MgO and CaO, and a ratio of (CaO (mol%)/(CaO (mol%) + MgO (mol%))) is less than or equal to 0.5; x mol% of Al₂O₃Wherein X is greater than or equal to about 2 mole% and less than or equal to about 10 mole%; and Y mol% of an alkali metal oxide, wherein the alkali metal oxide contains Na₂An amount of O greater than or equal to about 9 mol% and less than or equal to about 15 mol%, a ratio of Y to X greater than 1, and the glass composition being free of boron and boron compounds.

In another embodiment, the first exemplary glass composition may include about 74 mol% to about 78 mol% SiO₂(ii) a From about 3 mol% to about 13 mol% of an alkaline earth oxide comprising CaO and MgO, wherein the alkaline earth oxide comprises CaO in an amount greater than or equal to about 0.1 mol% and less than or equal to about 1.0 mol%, and a ratio of (CaO (mol%)/(CaO (mol%) + MgO (mol%))) less than or equal to 0.5; x mol% of Al₂O₃Wherein X is greater than or equal to about 2 mole% and less than or equal to about 10 mole%; and Y mol% of an alkali metal oxide, wherein the alkali metal oxide comprisesFrom about 0.01 mol% to about 1.0 mol% of K₂O and the ratio of Y to X is greater than 1, and the glass composition is free of boron and boron compounds.

In another embodiment, the first exemplary glass composition may include about 74 mol% to about 78 mol% SiO₂(ii) a From about 4 mol% to about 8 mol% of an alkaline earth oxide, wherein the alkaline earth oxide comprises an amount of CaO greater than or equal to about 0.1 mol% and less than or equal to about 1.0 mol%, MgO, and the ratio of (CaO (mol%)/(CaO (mol%) + MgO (mol%))) is less than or equal to 0.5; x mol% of Al₂O₃Wherein X is greater than or equal to about 4 mole% and less than or equal to about 8 mole%; and Y mol% of an alkali metal oxide, wherein the alkali metal oxide comprises greater than or equal to about 9 mol% and less than or equal to about 15 mol% of Na₂A ratio of O, Y: X is greater than 1, and the glass composition is free of boron and boron compounds, wherein the glass composition has a hydrolysis resistance of type HGA1 according to ISO 720.

In another exemplary embodiment, the glass container is formed from a delamination resistant glass composition such as the Alkaline Earth aluminosilicate glass composition described in U.S. provisional patent application No. 13/660,141 (attorney docket No. SP11-241), filed on 25/10/2012 And entitled "Alkaline Earth aluminosilicate glass composition with Improved Chemical And Mechanical Durability" (Alkaline Earth alumina-Silicate glass compositions with Improved Chemical And Mechanical Durability) ", the entire contents of which are incorporated herein by reference. This second exemplary glass composition generally includes SiO₂、Al₂O₃At least one alkaline earth metal oxide and alkali metal oxide (including at least Na)₂O and K₂O) in combination. This second exemplary glass composition is substantially free of boron and is free of boron-containing compounds. The combination of these ingredients makes the glass composition resistant to chemical degradation and also suitable for chemical strengthening by ion exchange. In some embodiments, the glass composition may further comprise a minor amount of one or moreAn additional oxide, e.g. tin oxide (SnO)₂) Zirconium oxide (ZrO)₂) Zinc oxide (ZnO), and the like. These ingredients may be added as fining agents and/or to further enhance the chemical durability of the glass composition.

In an embodiment of the second exemplary glass composition, SiO₂Is the largest component of the composition and is therefore the major component of the glass network. SiO 2₂Enhancing the chemical durability of the glass, particularly the resistance of the glass composition to decomposition in acid. Therefore, high SiO is generally required₂And (4) concentration. However, if SiO₂Too high content of (b) reduces the formability of the glass because of the higher SiO₂The concentration increases the difficulty of melting the glass, thereby adversely affecting the formability of the glass. However, the addition of alkali metal oxides can help to counteract this effect by lowering the softening point of the glass. In embodiments of this second exemplary glass composition, the glass composition typically comprises SiO in an amount greater than or equal to about 65 mol.% and less than or equal to about 75 mol.%₂. In some embodiments, the SiO present in the glass composition₂The amount is greater than or equal to about 67 mole% and less than or equal to about 75 mole%. In some other embodiments, the SiO present in the glass composition₂The amount is greater than or equal to about 67 mole% and less than or equal to about 73 mole%. In each of these embodiments, the SiO present in the glass composition₂The amount may be greater than or equal to about 70 mole percent or even greater than or equal to about 72 mole percent.

The second exemplary glass composition also includes aluminum oxide (Al)₂O₃)。Al₂O₃Together with alkali metal oxides (e.g., Na) present in the glass composition₂O, etc.) can improve the sensitivity of the glass to ion exchange strengthening. Further, Al is added₂O₃To this composition, the tendency of alkali metal components (e.g. Na or K) to be leached from the glass is reduced, and therefore, Al is added₂O₃The resistance of the composition to hydrolytic degradation is improved. The second exemplary glass composition described herein generally includes an amount greater than or equal to about 6 mol% andless than or equal to about 12.5 mol% Al₂O₃. In some embodiments, Al in the glass composition₂O₃In an amount greater than or equal to about 6 mole% and less than or equal to about 10 mole%. In some other embodiments, the Al in the glass composition₂O₃In an amount greater than or equal to about 7 mole% and less than or equal to about 10 mole%.

The second exemplary glass composition also includes at least two alkali metal oxides. The alkali metal oxide promotes ion exchangeability of the glass composition and thus promotes chemical strengthening of the glass substrate. The alkali metal oxide also lowers the softening point of the glass, thereby counteracting the higher SiO in the glass composition₂Concentration and increased softening point. The alkali metal oxide also contributes to the improvement in the chemical durability of the glass composition. The amount of alkali metal oxide present in the second exemplary glass composition is generally greater than or equal to about 5 mol.% and less than or equal to about 12 mol.%. In some of these embodiments, the amount of alkali metal oxide can be greater than or equal to about 5 mol% and less than or equal to about 10 mol%. In some other embodiments, the amount of alkali metal oxide may be greater than or equal to about 5 mol% and less than or equal to about 8 mol%. In all of the glass compositions described herein, the alkali metal oxide comprises at least Na₂O and K₂And O. In some embodiments, the alkali metal oxide further comprises Li₂O。

The ion exchangeability of the glass composition is mainly due to the alkali metal oxide Na initially present in the glass composition prior to ion exchange₂The content of O is added to the glass composition. In particular, to achieve the desired compressive strength and depth of layer in the glass composition after ion exchange strengthening, the second exemplary glass composition includes Na₂The amount of O is greater than or equal to about 2.5 mole percent and less than or equal to about 10 mole percent. In some embodiments, the glass composition may include Na in an amount greater than or equal to about 3.5 mol.% and less than or equal to about 8 mol.%₂And O. In these embodimentsIn some of (3), the glass composition may include Na in an amount greater than or equal to about 6 mol% and less than or equal to about 8 mol%₂O。

As indicated above, the alkali metal oxide in this second exemplary glass composition also includes K₂And O. K present in the glass composition₂The amount of O is also related to the ion exchangeability of the glass composition. In particular, when K is present in the glass composition₂As the amount of O increases, the compressive stress obtainable via ion exchange decreases. Therefore, it is desirable to limit the K present in the second exemplary glass composition₂And (4) the amount of O. In some embodiments, K₂The amount of O is greater than 0 mole% and less than or equal to about 2.5 mole%. In some of these embodiments, K is present in the glass composition₂The amount of O is less than or equal to about 0.5 mole percent.

In some embodiments, the alkali metal oxide in the second exemplary glass composition further comprises L₂And O. Including L in the glass composition₂O further lowers the softening point of the glass. Where the alkali metal oxide comprises L₂In the embodiment of O, L₂O may be present in an amount greater than or equal to about 1 mole% and less than or equal to about 3 mole%. In some embodiments, L present in the glass composition₂The amount of O is greater than about 2 mole% and less than or equal to about 3 mole%. However, in some other embodiments, the glass composition may be substantially free of lithium and free of lithium-containing compounds.

The alkaline earth metal oxide in the second exemplary glass composition may improve the meltability of the glass batch material and increase the chemical durability of the glass composition. Embodiments of the second exemplary glass composition generally include at least one alkaline earth oxide in a concentration greater than or equal to about 8 mol.% or even 8.5 mol.% and less than or equal to about 15 mol.%. In some embodiments, the glass composition may comprise from about 9 mol.% to about 15 mol.% alkaline earth oxide. In some of these embodiments, the amount of alkaline earth oxide in the glass composition may be from about 10 mol% to about 14 mol%.

The alkaline earth metal oxides in this second exemplary glass composition may include MgO, CaO, SrO, BaO, or combinations thereof. For example, in embodiments described herein, the alkaline earth metal oxide comprises magnesium oxide (MgO). The MgO is present in the glass composition in an amount greater than or equal to about 2 mol.% and less than or equal to about 7 mol.%, or even greater than or equal to about 3 mol.% and less than or equal to about 5 mol.%. In some other embodiments, the MgO concentration in the glass composition may be decreased to decrease the liquidus temperature and increase the liquidus viscosity of the glass composition, both of which may improve the formability of the glass composition. For example, in some embodiments, the concentration of MgO may be greater than 0 mol% and less than or equal to about 3.5 mol%. In some other embodiments, the concentration of MgO may be greater than 0 mol% and less than or equal to about 3.0 mol% or even less than or equal to about 2.5 mol%.

In some embodiments, the alkaline earth metal oxide in the second exemplary glass composition further includes calcium oxide (CaO). In these embodiments, the CaO is present in the glass composition in an amount from about 2 mol.% to less than or equal to about 7 mol.%. In some embodiments, CaO is present in the glass composition in an amount from about 3 mol.% to less than or equal to about 7 mol.%. In some of these embodiments, the amount of CaO present in the glass composition is greater than or equal to about 4 mol.% and less than or equal to about 7 mol.%. In some other embodiments, the amount of CaO present in the glass composition may be greater than or equal to about 5 mol% and less than or equal to about 6 mol%, such as when CaO replaces MgO in the alkaline earth oxides to lower the liquidus temperature and increase the liquidus viscosity. In other embodiments, the amount of CaO present in the glass may be greater than or equal to about 2 mol% and less than or equal to about 5 mol%, such as when SrO is substituted for MgO in the alkaline earth oxide to lower the liquidus temperature and increase the liquidus viscosity.

In some embodiments described herein, the alkaline earth metal oxide in the second exemplary glass composition further comprises at least strontium oxide (SrO) or barium oxide (BaO). Inclusion of SrO can lower the liquidus temperature of the glass composition and thus improve the formability of the glass composition. In some embodiments, the glass composition may include SrO in an amount greater than 0 mol% and less than or equal to about 6.0 mol%. In some other embodiments, the glass composition may include SrO in an amount greater than about 0 mol% and less than or equal to about 5 mol%. In some of these embodiments, the glass composition may include greater than or equal to about 2 mol% and less than or equal to about 4 mol% SrO, for example when CaO replaces MgO in the alkaline earth oxides to lower the liquidus temperature and increase the liquidus viscosity. In some other embodiments, the glass composition may include from about 1 mol% to about 2 mol% SrO. In other embodiments, the amount of SrO present in the glass composition may be greater than or equal to about 3 mole percent and less than or equal to about 6 mole percent, such as when SrO replaces MgO in alkaline earth oxides to lower the liquidus temperature and increase the liquidus viscosity.

In embodiments where the glass composition includes BaO, the amount of BaO present in the second exemplary glass composition may be greater than about 0 mol.% and less than about 2 mol.%. In some of these embodiments, the amount of BaO present in the glass composition may be less than or equal to about 1.5 mol.% or even less than or equal to about 0.5 mol.%. However, in some other embodiments, the glass composition is free of barium and barium compounds.

In embodiments of the second exemplary glass composition described herein, the glass composition typically contains less than about 1 mol% boron or boron oxide (e.g., B)₂O₃). For example, in some embodiments, the glass composition may comprise greater than or equal to about 0 mol% B₂O₃And less than or equal to about 1 mole% of B₂O₃. In some other embodiments, the glass composition may include greater than or equal to about 0 mol% B₂O₃And less than or equal to about 0.6 mole% of B₂O₃. In other embodiments, the glass composition is substantially free of boron and boron compounds (e.g., B)₂O₃). In particular, it has been determined that forming a glass composition with a relatively low amount (i.e., less than or equal to about 1 mole%) of boron or boron compounds or no boron or boron compounds can significantly improve the chemical durability of the glass composition and reduce the susceptibility to delamination. Further, it has been determined that forming glass compositions with lower amounts of boron or boron compounds or no boron or boron compounds can improve the ion exchangeability of the glass compositions by reducing the process time and/or temperature required to achieve a particular compressive stress value and/or depth of layer.

Except for SiO₂、Al₂O₃The second exemplary glass compositions described herein may optionally further comprise one or more fining agents, such as tin oxide (SnO)₂) Arsenic trioxide (As)₂O₃) And/or Cl^-(from NaCl, etc.). When present in the glass composition, the fining agent may be present in an amount less than or equal to about 0.5 mol%. For example, in some embodiments, the glass composition may include SnO as a fining agent₂. In these embodiments, SnO may be present in the glass composition₂The amount is greater than about 0 mole% and less than or equal to about 0.30 mole%.

In addition, the glass compositions described herein may include one or more additional metal oxides to further improve the chemical durability of the glass compositions. For example, the glass composition may further comprise zinc oxide (ZnO) or zirconium oxide (ZrO)₂) Each of which further improves the chemical resistance of the glass composition. In these embodiments, the additional metal oxide may be present in an amount greater than or equal to about 0 mol% and less than or equal to about 2.0 mol%. For example, when the additional metal oxide is ZrO₂Of (i) ZrO₂May be present in an amount less than or equal to about 1.5 mole percent. Alternatively or additionally, the additional metal oxide may comprise ZnOThe amount of (a) is less than or equal to about 2.0 mole%. In some embodiments, ZnO may be included as a substitute for one or more alkaline earth metal oxides. For example, in embodiments where the glass composition includes the alkaline earth oxides MgO, CaO, and SrO, the amount of MgO may be reduced to lower the liquidus temperature and increase the liquidus viscosity, as described above. In these embodiments, ZnO may be added to the glass composition as a partial substitute for MgO in addition to or in place of at least one of CaO or SrO.

To provide a glass composition that can be easily formed into a 3-dimensional shape, the molten glass formed from the second exemplary glass composition typically has a liquidus viscosity of greater than or equal to about 90 kilopoise (kP). It has been determined that glass compositions having a liquidus viscosity greater than 90kP can be obtained by controlling the ratio of MgO to the sum of the concentrations of divalent cations (Σ RO). Divalent cations include alkaline earth metal oxides (e.g., MgO, CaO, SrO, BaO), ZnO, and the like. In particular, it has been determined that when MgO: Σ RO is less than about 0.30, the glass composition generally has a liquidus viscosity greater than or equal to about 90kP, preferably the glass composition has a liquidus viscosity greater than or equal to about 100kP or even greater than or equal to about 115 kP. Accordingly, in some embodiments described herein, the ratio of MgO: Σ RO is less than about 0.3.

Based on the foregoing, it should be appreciated that, in one embodiment, the second exemplary glass composition may include: from about 65 mol% to about 75 mol% SiO₂(ii) a From about 6 mol% to about 12.5 mol% Al₂O₃(ii) a And from about 5 mol% to about 12 mol% of an alkali metal oxide, wherein the alkali metal oxide comprises Na₂O and K₂O。K₂O may be present in an amount less than or equal to 0.5 mole%. The glass composition may also include from about 8.0 mol.% to about 15 mol.% of an alkaline earth oxide. The glass composition can be readily strengthened by ion exchange.

In another embodiment of the second exemplary glass composition, the glass composition comprises from about 67 mol.% to about 75 mol.% SiO₂(ii) a From about 6 mol% toAbout 10 mol% of Al₂O₃(ii) a From about 5 mol% to about 12 mol% of an alkali metal oxide; and from about 8 mol% to about 15 mol% of an alkaline earth oxide. K which the alkali metal oxide may comprise₂The amount of O is less than or equal to about 0.5 mole percent. The alkaline earth metal oxide may include at least one of SrO and BaO. The glass composition may be free of boron and boron compounds and phosphorus compounds. The glass composition can be ion exchanged to a depth of layer of greater than or equal to about 15 μm and have a corresponding compressive stress of greater than or equal to about 250 MPa.

In yet another embodiment of the second exemplary glass composition, the glass composition may include from about 67 mol.% to about 75 mol.% SiO₂(ii) a From about 6 mol% to about 10 mol% Al₂O₃(ii) a From about 5 mol% to about 12 mol% of an alkali metal oxide; and from about 9 mol% to about 15 mol% of an alkaline earth oxide. The alkaline earth metal oxide contains at least one of SrO and BaO. The glass composition is free of boron and boron compounds and is readily ion exchanged to facilitate chemical strengthening of the glass to improve mechanical durability.