Chemically strengthened glass container manufactured on basis of ion exchange process and manufacturing method thereof

Abstract

The method for chemically strengthening a glass container on the basis of an ion exchange process comprises the steps of: preparing a slurry by mixing a salt and metal oxide particles; applying the slurry to one or more of at least a portion of the outer wall surface and at least a portion of the inner wall surface of the glass container; and heat-treating the glass container to which the slurry has been applied, wherein each of the preparing step, the applying step, and the heat-treating step may be performed in consideration of one or more of: a shape characteristic of the glass container having an inner wall and an outer wall; a curvature change characteristic for each part; and thermal stability of a coating film in the heat-treating step.

Description

Chemically strengthened glass container manufactured based on ion exchange process and manufacturing method thereof

[0001] The present invention relates to a method for manufacturing a glass container by chemically strengthening it through an ion exchange process, and to a chemically strengthened glass container manufactured by this method. More specifically, the present invention relates to a chemically strengthened glass container that can be provided with location-selective ion exchange properties and further has improved pressure-resistant properties by forming a coating film using a slurry containing metal oxide particles at room temperature and dry-strengthening the film.

[0002] Methods for strengthening glass by applying compressive stress to its surface are broadly categorized as physical strengthening and chemical strengthening. Chemical strengthening applies compressive stress to the surface by replacing sodium or lithium ions within the glass with external alkaline ions with larger ionic radii, such as potassium ions. It can be applied to thinner glass than physical strengthening, and its demand has recently diversified, and it is being applied to a wider range of fields such as automobile window glass and pharmaceutical packaging in addition to the cover windows of existing mobile electronic devices. In the case of general-purpose plate glass and glass containers, efforts to reduce glass thickness are ongoing as a means of reducing greenhouse gas emissions caused by raw materials and fuel. In this case, the demand for processes that apply chemical strengthening is expected to increase significantly compared to physical strengthening.

[0003] Ion exchange processes for chemical strengthening can be broadly categorized into wet and dry methods. The wet method, which immerses the glass to be strengthened in a molten alkali salt to cause ion exchange, is the most widely used method. While the wet method can ensure uniform ion exchange performance across the entire glass, it requires a salt bath approximately 400-1,000,000 times the mass of the glass, which poses cost and environmental issues. Furthermore, in the wet method, to intentionally impart different ion exchange effects depending on the location of the glass, a densely formed masking that prevents the molten alkali salt from penetrating is required, which reduces process yield and increases unit costs. Furthermore, applying the wet method to glass containers requires a jig design that prevents the glass from floating during immersion. Furthermore, the liquid molten salt that enters the glass after ion exchange must be removed, which can lead to additional costs and environmental issues.

[0004] Furthermore, in other cases of strengthening glass containers using wet ion exchange, only a portion of the glass container was immersed in an alkaline molten salt, resulting in external strengthening only (US 2020 / 1040328A1). While this method improves the mechanical properties of the glass container, it also creates tensile stress on the inner wall, resulting in pressure characteristics similar to or significantly reduced compared to unreinforced glass containers. Furthermore, a concept has been proposed that allows for controlling the degree of strengthening depending on the location by adjusting the height and direction of immersion in the molten salt. However, this method suffers from the disadvantage of not being able to strengthen both the upper and lower portions of the glass container simultaneously.

[0005] In contrast, the dry process involves preparing a slurry or paste containing an alkaline salt and applying it to a glass surface to initiate ion exchange. While this process offers the advantages of facilitating location-selective ion exchange through selective application of the coating, and controlling the composition of the coating allows for the desired level of ion exchange, it also suffers from uneven ion exchange, leading to irregular deformation and surface contamination, hindering its commercial application.

[0006] Meanwhile, a method of strengthening by spraying molten KNO3 salt at high temperatures onto the surface of a rotating glass bottle using a dry ion exchange method has been proposed (KR102722722B1). Since this technology sprays low-viscosity molten KNO3 salt, it is difficult to form a thick coating film, and the coating film runs off, resulting in a decrease in ion exchange characteristics and unevenness. In addition, when strengthening is performed using this method, it is difficult to strengthen the bottom, so there is a disadvantage that the pressure resistance performance is similar to or lower than that of non-strengthened glass. In addition, similar to the wet method described above, when performing location-selective ion exchange, a masking with excellent heat resistance is required, which increases the cost.

[0007] A case study on dry ion exchange for plate glass was presented, in which metal oxide particles were introduced into the slurry to improve ion exchange uniformity and contamination issues compared to conventional clay-based dry ion exchange processes (KR20190123237A). While this technology demonstrated excellent ion exchange uniformity for glass with limited curvature, such as plate or curved glass, maintaining a stable coating on shapes with complex curvatures, such as container glass, and implementing dry ion exchange based on this coating requires prior assurance of the thermal stability of the coating.

[0008] Typically, colored plate glass or container glass is manufactured by adding a colorant during the raw material mixing stage. Separately, there is a case in which color-changing properties were imparted to colorless, transparent plate glass through ion exchange with silver or copper ions (KR102363123B1). A similar mechanism can be applied to container glass, but in reality, cases in which color-changing properties were imparted to container glass through ion exchange are rare.

[0009] In addition, there are cases where a heat strengthening process is applied to improve the durability of glass containers, but special equipment is required to spray compressed air on the bottom and inside of the glass container, and there is a technical limitation that the strengthening effect is significantly limited, especially when strengthening borosilicate glass with a low coefficient of thermal expansion (WO2011150039A2).

[0010] In addition, a technology has been reported that simultaneously applies thermal strengthening and chemical strengthening methods by maintaining the target glass above the transition temperature and then rapidly cooling it by contacting it with a coolant containing an alkaline component (US20230312388A1). In this method, since the coolant containing an alkaline component is in a liquid state, the process temperature must be maintained at 334°C or higher, which is higher than the melting point of potassium nitrate, or 220°C or higher, which is higher than the melting point of a mixture of potassium nitrate and sodium nitrate. In addition, there are limitations in controlling the cooling rate due to the characteristics of the coolant, which may reduce the level of thermal strengthening (G. Macrelli, AK Varshneya, S. Karlsson, JC Mauro, Glass Technol.: Eur. J. Glass Sci. Technol. A, 65, (2024) 65-88.).

[0011] The present invention is intended to solve the problems of the prior art as described above, and to provide a room temperature process-based dry ion exchange method with improved pressure resistance by providing ion exchange characteristics at a level similar to that of the wet method while solving the limitations of the prior art wet method and the dry method of spraying at high temperatures, and a glass container strengthened by the method.

[0012] In addition, the present invention aims to provide a technology capable of imparting uniform ion exchange strengthening properties to container glass having complex curvatures by solving problems such as non-uniformity of the coating film and deterioration of process reproducibility that occur in the process of applying a dry ion exchange process for plate glass using a slurry containing metal oxide particles to the shape of container glass.

[0013] The glass container of the present invention is a structure having a hollow layer manufactured by molding glass or a material containing glass as a main component, and typically includes one or more of the following components. The base portion (base or bottom portion, 1) is the lowest portion that directly contacts the ground when the glass container is placed vertically, and may be formed in the shape of a plane or a curved surface having one or more curvatures. The wall portion (wall or body portion, 2) is continuously connected to the base portion (1) and is formed with an outer surface and an inner surface that are vertical to the ground or have an inclination angle of ±45° or less. At this time, the horizontal cross-section has a closed surface or a polygonal shape, and this shape may change in size or shape depending on the height. The shoulder portion (shoulder portion, 3) is continuously connected to the wall portion (2) and may be formed in a shape that gradually narrows toward the central axis of the glass container. At this time, the horizontal cross-section may be formed in the shape of a closed surface or a polygon. The neck portion (4) is continuously connected to the shoulder portion (3) and is a portion that extends toward the opening of the glass container. At this time, the horizontal cross-section can be formed as a closed surface or a polygonal shape, and the outer diameter and length can be designed in various ways depending on the application. The finish portion or seal surface portion (5) is continuously connected to the neck portion (4) or the wall portion (2) and is located at the top of the glass container, and is a portion that performs a sealing function including an opening to the outside. Depending on the application, it can be narrowed or widened, or formed into various shapes such as a spout, a screw, a crimp, or a flange. The above-mentioned components are each continuously connected to adjacent components through a curved surface having a discontinuity, and are implemented as a glass container shape having a closed or open three-dimensional shape including a hollow layer.In particular, the connecting portion of each component is formed as a curved surface with a finite curvature, thereby providing the effect of relieving uneven stress applied to the glass container during processes such as forming, transport, and storage.

[0014] As examples of the above-described configuration combinations, glass cups and beakers typically include a base portion (1) and a wall portion (2), and are formed with an injection port in a finish portion (5) depending on the intended use. For example, an ampoule-shaped glass container includes a base portion (1), a wall portion (2), a shoulder portion (3), a neck portion (4), and a finish portion (5), wherein the finish portion is mainly formed in the form of a sealable thin glass tube and sealed. In the case of typical bottle-shaped glass containers such as beverage and cosmetic containers, pharmaceutical vials, and cartridges, the base portion (1), the wall portion (2), and the shoulder portion (3) are basically included, and one or more of the neck portion (4) or the finish portion (5) may be additionally included as needed.

[0015] In the prior art, when dry ion exchange of glass is performed, the coating film is composed of a composition containing clay as a support. However, when the process is directly applied to a container glass, there is a problem that the coating film peels off or cracks in areas with high curvature (e.g., wall areas, joints between areas, etc.) during the process steps (e.g., drying, ion exchange heat treatment, etc.). The present invention provides a slurry composition suitable for dry ion exchange of a glass container having a significantly high curvature due to its closed-curve shape compared to flat or curved glass, a coating and dry ion exchange process capable of maintaining the adhesion and stability of the coating film in the entire process, and a glass container product manufactured through the process with improved durability and quality.

[0016] Furthermore, the dry process-based coating film implemented in the embodiments of the present invention ensured excellent thermal stability. In particular, the coating film was maintained without defects even under rapid temperature changes of up to 270°C / min, enabling rapid temperature rise steps to be utilized when applying a continuous ion exchange process. The coating film of the present invention can maintain stability not only under static heat treatment conditions but also under dynamic temperature changes accompanied by rapid temperature changes. Furthermore, it is applicable to a high-speed heat treatment process that dynamically controls the heating and cooling rates to improve overall process efficiency. Furthermore, it is expected to be utilized in a fusion process with a thermal strengthening process that requires rapid cooling after chemical strengthening. For example, it is possible to use the target glass as a coolant and ion source to induce ion exchange simultaneously by heating the target glass above its glass transition temperature and then spraying a room temperature metal oxide particle slurry.

[0017] However, the technical tasks to be achieved by the embodiments of the present invention are not limited to the technical tasks described above, and other technical tasks may exist.

[0018] As a technical means for achieving the above-mentioned technical task, the present invention applies a dry ion exchange process to a glass container, and more specifically, it is characterized by selectively forming a coating film on the entirety or part of the glass container with an alkali salt slurry containing metal oxide particles at room temperature and performing ion exchange in a dry manner. Therefore, in an embodiment of the present invention, a coating film was formed on the entirety or part of the outside and inside of a Type I glass vial through a dry method using an alkali salt slurry containing metal oxide particles that can be applied at room temperature, and a heat treatment for ion exchange was performed to impart a chemical strengthening effect, and then the ion exchange characteristics and uniformity of the glass container were confirmed. According to one embodiment of the present invention, it was confirmed that when utilizing the above-mentioned dry ion exchange method, a similar level of ion exchange uniformity and performance can be achieved using a much smaller amount of starting materials than the existing wet method in the composition of Type I borosilicate glass. According to one embodiment of the present invention, it was confirmed that internal coating inside a glass container is possible using the above-described dry ion exchange method, and at this time, it was confirmed that the degree of ion exchange generated by the internal coating can form sufficient compressive stress without significantly reducing the chemical durability of the glass. In addition, according to one embodiment of the present invention, site-selective ion exchange can be easily induced compared to the prior art, and further, based on the site-selective ion exchange technology, additional reinforcement can be performed on the stress concentration area of ​​the glass container, thereby improving mechanical properties such as pressure resistance characteristics.

[0019] According to one embodiment of the present invention, when the viscosity of the slurry is controlled in the coating process from about 450 mPa·s to about 1600 mPa·s, it was confirmed that the coating quality based on the paste process is uniform, and the coating film is stably maintained even when the temperature changes rapidly during the ion exchange heat treatment, thereby improving the thermal stability. In addition, since the higher the viscosity in the storage and drying process, the more the flow of the slurry is restricted and thus the more stably it is maintained, it is preferable to utilize a viscosity enhancer that exhibits shear thinning.

[0020] According to one embodiment of the present invention, a coating film formed based on a spray process was maintained stably even when the maximum temperature change rate was 180 ℃ / min during ion exchange heat treatment, and a coating film based on a paste process exhibited excellent stability without cracking or peeling up to 270 ℃ / min. In particular, no defects in the coating film were observed even in areas with large curvatures, such as the connection between each component of a glass container and the outer wall, and the shape and adhesion of the coating film were maintained even under high-temperature and long-term ion exchange conditions of 450 ℃ for 16 hours. This high thermal stability of the coating film is not only suitable for a continuous ion exchange process accompanied by rapid temperature changes, but also suggests that the dry process can be applied to a fusion process with physical strengthening that requires rapid cooling before and after chemical strengthening. Specifically, it is believed that by spraying a room temperature spray on the glass during the process of heating above the glass transition temperature and then cooling it, or by immersing it in a room temperature paste by dip coating, it is possible to impart both thermal strengthening and chemical strengthening effects simultaneously. In addition, since a temperature of at least 220℃, which is the melting temperature of the alkali salt when using a molten alkali salt as a coolant, which is a known technology, is required compared to the technology, it is believed that by using a room temperature coolant, the rapid cooling speed can be improved, thereby imparting a more excellent thermal strengthening effect.

[0021] The technical means for achieving the technical tasks of this institute are summarized as follows.

[0022] As a technical means for achieving the above-described technical task, a method for chemical strengthening a glass container based on an ion exchange process according to one embodiment of the present invention comprises the steps of: preparing a slurry by mixing a salt and metal oxide particles; applying the slurry to at least one of at least a portion of an outer wall surface and at least a portion of an inner wall surface of a glass container; and heat-treating the glass container to which the slurry is applied, wherein each of the preparing step, the applying step, and the heat-treating step may be performed in consideration of at least one of the geometrical characteristics of the inner wall and the outer wall of the glass container, the characteristics of the curvature change by region, and the thermal stability of the coating film in the heat-treating step.

[0023] In addition, the glass container has a shape of a container having an internal hollow portion including a base portion, a wall portion, a shoulder portion, and a neck portion, and an opening formed at an end of the neck portion, and the curvature change characteristic for each portion may be a curvature change characteristic at one or more of a connection portion among a connection portion between the base portion and the wall portion, a connection portion between the wall portion and the shoulder portion, and a connection portion between the shoulder portion and the neck portion.

[0024] In addition, in the manufacturing step, the slurry is manufactured with a viscosity corresponding to each of the inner and outer walls of the glass container, taking into account the different difficulty of applying the slurry between the inner and outer walls due to the shape in which the width of the opening in the glass container is narrower than the width of the inner hollow, and in the applying step, the method of applying the slurry can be selectively applied to each of the inner and outer walls of the glass container, taking into account the different difficulty of applying the slurry.

[0025] In addition, the coating method corresponding to the outer wall of the glass container is a spray coating method or a dip coating method, and the coating method corresponding to the inner wall of the glass container is a drainage coating method, a spray coating method, or a brush coating method. When spray coating is applied to both the outer wall and the inner wall of the glass container, the viscosity of the slurry applied corresponding to the inner wall can be maintained higher than the viscosity of the slurry applied corresponding to the outer wall.

[0026] In addition, in order to consider the characteristics of the curvature change by the above-mentioned part, the uniformity of the coating film in the above-mentioned applying step, and the thermal stability of the coating film in the above-mentioned heat treatment step, in the above-mentioned manufacturing step, the slurry is manufactured so that the viscosity of the slurry applied in the above-mentioned applying step is 13 mPa·s or more and 750 mPa·s or less, and in the above-mentioned applying step, the slurry can be applied by a spray coating method when the viscosity is 13 mPa·s or more and 750 mPa·s or less.

[0027] In addition, in order to consider the characteristics of the change in curvature by the above-mentioned part, the uniformity of the coating film in the coating step, and the thermal stability of the coating film in the heat treatment step, in the manufacturing step, the slurry is manufactured so that the viscosity of the slurry applied in the coating step is 450 mPa·s or more and 1600 mPa·s or less, and in the coating step, the slurry can be applied by one or more of a dip coating method, a drainage coating method, and a brush coating method when the viscosity is 450 mPa·s or more and about 1600 mPa·s or less.

[0028] Additionally, the salt may include at least one of an alkali salt, a silver salt, a gold salt, or a copper salt.

[0029] Additionally, the slurry may further include a viscosity enhancer.

[0030] Additionally, the temperature of the above-mentioned applying step may be room temperature.

[0031] Additionally, in the heat treatment step, the heat treatment temperature may be 220°C or higher and 550°C or lower.

[0032] Additionally, the applying step and the heat treatment step can be performed as a dry process.

[0033] In addition, the heat treatment step is performed in a dynamic temperature change section in which the temperature changes over time by utilizing the relatively low heat capacity characteristics of the coating film formed in the dry process compared to the wet process, and the temperature change rate in the dynamic temperature change section can be set to a maximum of 270 ℃ / min or less in consideration of defects in the coating film that may occur due to the geometric characteristics of the inner and outer walls of the glass container and the curvature change characteristics by region.

[0034] Additionally, in the above dynamic temperature change section, the temperature change rate can be set to 180 ℃ / min or less.

[0035] Additionally, in the heat treatment step, the dynamic temperature change section may include a temperature increase and heat treatment section.

[0036] In addition, the dynamic temperature change section may have a temperature change rate in the temperature increase section of at most 270 ℃ / min or less, preferably at least 180 ℃ / min or less, and a temperature change rate in the heat treatment section of at most 110 ℃ / min or less, preferably at least 70 ℃ / min or less.

[0037] In addition, in the heat treatment step, a room temperature metal oxide slurry can be used as a coolant to cool the surface of the glass heated above the glass transition temperature, thereby simultaneously providing thermal strengthening and chemical strengthening effects.

[0038] In addition, the stress concentration portion may include at least one of the base portion of the glass container, the upper portion of the wall portion, the lower portion of the wall portion, the shoulder portion, the connection portion between the base portion and the wall portion, the connection portion between the wall portion and the shoulder portion, and the connection portion between the shoulder portion and the neck portion.

[0039] In addition, in the manufacturing step and the applying step, in consideration of the stress concentration area of ​​the glass container, the coating film is selectively applied to the application area, or at least one of the composition, thickness, and weight of the coating film is locally applied differently, by not forming the coating film at a location other than the stress concentration area, or by manufacturing the slurry in the manufacturing step so that the salt content of the slurry applied to the stress concentration area is higher than that of a location other than the stress concentration area, or by forming the thickness and weight of the coating film applied to the stress concentration area in the applying step smaller than that of a location other than the stress concentration area, the method can be provided so that an ion exchange characteristic gradient exists between the stress concentration area and other regions during ion exchange of the outer wall or the inner wall.

[0040] In addition, the above-described applying step is performed so that ion exchange occurs on the inner wall, taking into account the stress concentration area of ​​the glass container, and the ion exchange area of ​​the inner wall may include at least the base of the glass container.

[0041] In addition, when ion exchange is performed on the inner wall of the glass container, in order to prevent the chemical stability inside the glass container from deteriorating, the concentration of ion exchanged on the surface of the inner wall, c i The maximum value of is provided to be less than or equal to 0.75, where c i It can mean the ratio of the concentration of ion-exchanged ions to the total alkaline ion concentration in the glass.

[0042] In addition, when ion exchange is performed on the inner and outer walls of the glass container, in order to secure chemical stability inside the glass container and at the same time prevent tensile stress from forming on the surface of the inner wall, at least one of the composition, thickness and weight of the coating film applied between the inner and outer walls is set differently, so that the salt content of the slurry applied to the outer wall in the slurry manufacturing step is manufactured to be higher than that of the inner wall, or the thickness and weight of the coating film applied to the outer wall in the coating step are formed to be smaller than that of the inner wall, and the ion concentration and surface compressive stress ratio exchanged on the surface between the inner and outer walls of the glass container satisfy the following equations:

[0043] [ceremony]

[0044]

[0045] Here, c o and c i are the surface alkali concentration of the outer wall and the surface ion concentration of the inner wall, σ, respectively. o and σ i are the surface compressive stresses of the outer and inner walls, respectively, C d where t represents the diffusion depth and t represents the thickness of the glass.

[0046] Meanwhile, as a technical means for achieving the above-described technical task, the organic container according to one embodiment of the present invention is a glass container manufactured by the above method, and may be any one of a chemically strengthened glass container, a color-changing glass container, and an antibacterial glass container.

[0047] Additionally, the glass container may not have tensile stress in at least one of a portion of the outer wall surface and a portion of the inner wall surface.

[0048] The above-described problem-solving methods are merely exemplary and should not be construed as limiting the present invention. In addition to the exemplary embodiments described above, additional embodiments may be included in the drawings and detailed description of the invention.

[0049] According to the aforementioned means for solving the problem of the present invention, an alkaline salt slurry including metal oxide particles can be applied to the exterior and interior of a glass container at room temperature, thereby providing a dry-type chemically strengthened glass container and a method for manufacturing the same. According to one embodiment of the present invention, by selectively ion-exchanging a region where stress is concentrated during the transport and filling process of the glass container or by applying a gradient to the degree of ion exchange, a glass container with improved pressure resistance characteristics can be provided through external ion exchange alone.

[0050] According to the solution to the problem of the present invention described above, by utilizing a coating film with improved thermal stability, uniform ion exchange can be performed even on objects having complex three-dimensional shapes such as glass containers, and when applied to a continuous ion exchange process, the time required for heating and cooling can be shortened, or the slurry can be sprayed at room temperature during the thermal strengthening process to provide thermal and chemical strengthening effects simultaneously. According to one embodiment of the present invention, the uniformity and thermal stability of the coating film can be improved by controlling the viscosity during the slurry preparation.

[0051] However, the effects that can be obtained from this center are not limited to the effects described above, and other effects may exist.

[0052] Figure 1 is a drawing showing the specifications and shape of a glass vial used in an example of the present invention.

[0053] Figure 2 is a graph showing the viscosity of slurries without added viscosity enhancer as a function of the relative molar concentration ratio of TiO2 to the total molar concentration of KNO3 and TiO2 in the slurry.

[0054] Figure 3 shows the results of applying a metal oxide particle-based alkaline salt slurry to three types of glass vials with different specifications and shapes using a room temperature spray process (photograph after the coating film has dried).

[0055] Figure 4 is a drawing showing the change in shape of the coating film before and after ion exchange when two types of glass vials with different specifications and shapes were placed in an electric furnace while standing and ion exchange was performed at 450, 500, and 550°C for 16, 5, and 2 hours, respectively (shape of the coating film before and after ion exchange).

[0056] Figure 5 is a drawing showing the shape of a glass vial after removal of the coating film after ion exchange at 450, 500 and 550°C for 16, 5 and 2 hours, respectively (glass vial after removal of the coating film).

[0057] Figure 6 is a photograph showing the shape of a glass vial observed with a polarizer after the coating film was removed after ion-exchange at 450, 500, and 550°C for 16, 5, and 2 hours, respectively (glass vial after the coating film was removed; polarizer photograph).

[0058] Figure 7 is a photograph showing the results of CS and DOL measurements of glass vials ion-exchanged at 400, 450, 500, and 550°C for 24, 9, 5, and 3 hours, respectively, using FSM equipment (CS and DOL by ion-exchange temperature).

[0059] Figure 8 shows the results of measuring the alkali concentration distribution in the ion exchange depth direction in the body region of glass vials ion-exchanged at 400, 450, 500, and 550°C for 24, 9, 5, and 3 hours, respectively, using SEM-EDS (alkali concentration distribution by ion exchange temperature).

[0060] Figures 9 and 10 are graphs showing the results of measuring CS and DOL (Figure 9 shows CS and DOL according to ion exchange temperature of a crimp neck vial, Figure 10 shows CS and DOL according to ion exchange temperature of a screw neck vial) of glass vials ion-exchanged at 450, 500, and 550°C for 16, 5, and 2 hours, respectively, using FSM equipment.

[0061] Figure 11 shows the results of measuring the alkali concentration distribution in the ion exchange direction by position in a glass vial that was ion-exchanged at 500°C for 5 hours using SEM-EDS (alkali concentration distribution by glass vial position).

[0062] Figure 12 is a drawing showing the measurement locations of the concentration distribution of Figure 11 (alkali concentration measurement locations by glass vial location).

[0063] Figure 13 shows the results of measuring the hardness (hardness according to ion exchange conditions) of ion-exchanged or non-ion-exchanged glass vials at 450, 500, and 550°C for 16, 5, and 2 hours, respectively, using a Vickers hardness tester.

[0064] Figure 14 is a drawing showing the location where Vickers hardness was measured in a glass vial (hardness measurement location).

[0065] Fig. 15 is a diagram showing the results of temperature measurement according to the composition of insulation material loaded into an electric furnace and the set temperature. Fig. 15 (a) is a graph showing the results of temperature measurement when insulation material is not loaded, and Fig. 15 (b) is a graph showing the results of temperature measurement when insulation material is loaded.

[0066] Fig. 16 is a diagram showing the temperature change rate according to the insulation material configuration loaded into the electric furnace and the set temperature. Fig. 16 (a) is a graph showing the temperature change rate in the temperature raising stage, and Fig. 16 (b) is a graph showing the temperature change rate in the temperature maintenance stage after the temperature raising is completed.

[0067] Fig. 17 is a drawing of the shape of the coating film of a glass vial immediately after ion exchange. Fig. 17 (a) is a photograph showing the shape of a glass vial immediately after ion exchange at 450°C for 4 hours, and Fig. 17 (b) is a photograph showing the shape of a glass vial immediately after ion exchange at 500°C for 2 hours.

[0068] Figure 18 is a drawing showing the coating film and the film removal after ion-exchange of a glass vial under controlled temperature change conditions according to heat treatment conditions.

[0069] Figure 19 shows the visual and polarimetric photographs of glass vials wet-ion exchanged at 450, 500, and 550°C for 16, 5, and 2 hours, respectively (glass vials after wet-ion exchange).

[0070] Figure 20 is a graph showing the CS and DOL measurement results (CS and DOL during wet ion exchange) of glass vials ion-exchanged in a wet manner at 450, 500, and 550°C for 16, 5, and 2 hours, respectively, using FSM equipment.

[0071] Figures 21 to 23 are photographs of each specimen after drying of the coating film of a glass vial subjected to ion exchange in a dry manner, after ion exchange, and after removal of the coating film (Figure 21 is a photograph of the coating film after drying, Figure 22 is a photograph of the coating film after ion exchange, and Figure 23 is a photograph of the coating film removed after ion exchange).

[0072] Fig. 24 is a drawing regarding the CS and DOL of ion-exchanged glass vials. Fig. 24 (a) is a drawing showing the results of measuring CS and DOL of glass vials ion-exchanged at 450°C for 16 hours using FSM equipment, and Fig. 24 (b) is a drawing showing the results of measuring CS and DOL of each specimen of glass vials ion-exchanged at 450°C for 2 hours.

[0073] Figure 25 is a schematic diagram showing the dip coating method and the brush coating method among paste-based processes for forming a coating film on the outside of a glass vial.

[0074] Figure 26 is a graph showing the viscosity measurement results for slurry content versus the spindle speed of a rotary viscometer.

[0075] Figure 27 is a drawing showing the results (after drying of the coating film) of applying slurry to a glass vial using a dip coating process under different conditions of slurry composition and drawing speed.

[0076] Figure 28 is a drawing showing a cross-section of a coating film taken with an optical microscope under some conditions selected from among the coating films of Figure 27. Here, the thickness of the coating film is indicated by an arrow.

[0077] Figure 29 is a drawing showing the shape of a coating film that was ion-exchanged at 450°C for 16 hours using the glass vial of Figure 27.

[0078] Figure 30 is a graph showing the CS and DOL measurement results (CS and DOL during ion exchange using the deep coating method) of the ion-exchanged glass vials shown in Figure 29 in relation to the slurry composition and extraction speed.

[0079] Figure 31 is a drawing showing photographs of the coating film before and after ion exchange of a glass vial in which a slurry composition including a viscosity enhancer was applied to a glass vial, dried, and then placed in an electric furnace without insulation and ion-exchanged at 500°C for 5 hours.

[0080] Figure 32 is a drawing showing photographs of a coating film after applying and drying a slurry composition having a different viscosity-improving agent content ratio to a glass vial, according to the slurry composition and drawing speed.

[0081] Figure 33 is a graph showing the results of CS and DOL measurements of glass vials ion-exchanged by a dip-coating dry method at 450°C for 6 hours. Figure 33 (a) is a graph showing CS and DOL against slurry composition, and Figure 33 (b) is a graph showing the product of CS and DOL against the weight of the coating film of each specimen.

[0082] Figures 34 to 36 are photographs of each specimen after drying of the coating film of a glass vial subjected to external ion exchange using the dry paste method, after ion exchange, and after removal of the coating film (Figure 34 is a photograph of the coating film after drying, Figure 35 is a photograph of the coating film after ion exchange, and Figure 36 is a photograph of the coating film removed after ion exchange).

[0083] Figure 37 is a drawing showing the shape of a coating film before and after ion exchange in a metal oxide slurry with added viscosity enhancer, with respect to the potassium nitrate content in the coating film and the ion exchange heat treatment temperature.

[0084] Figure 38 is a graph showing CS and DOL measurements of glass vials ion-exchanged at 500, 450, and 450°C for 5, 6, and 16 hours, respectively, under ion-exchange conditions with controlled alkali salt content in the slurry.

[0085] Figure 39 is a simplified schematic diagram of the stress distribution during double-sided asymmetric ion exchange.

[0086] Figure 40 is the minimum σ that can offset the CT according to the thickness of the glass and the change in DOL based on mathematical equation 3. i / σ o ratio (minimum σ that can relieve the inner wall tensile stress) i / σ o This is a figure showing the calculation of the ratio, and Fig. 41 is based on the results calculated in Fig. 39. o When changes at least σ i The value of (σ in glass with a wall thickness of 1.2 mm) o σ according to change in value i This is a figure that derives the minimum value of .

[0087] Figure 42 is a side view photograph (a side view photograph of a vial after coating the inside of a screw neck glass vial) when a metal oxide particle-based alkali salt slurry is applied to the inside of two types of screw neck vials using a room temperature spray process, and Figure 43 is a bottom view photograph (a bottom view photograph of a vial after coating the inside of a screw neck glass vial).

[0088] Figure 44 is a picture showing a photograph (after ion exchange inside a screw neck glass vial) taken by observing with a polarizer before and after removing the coating film after heat treatment at 450°C for 40 hours in a glass vial having a coating film formed inside the glass vial using the method described above.

[0089] Fig. 45 is a graph showing the results of measuring the alkali concentration distribution in the ion exchange direction at the bottom of a glass vial after the removal of the coating film after internal ion exchange (alkali concentration distribution during ion exchange inside a screw neck glass vial) using SEM-EDS, and the concentration measurement locations are marked. Fig. 46 is a picture showing the bottom photograph (bottom photograph after internal application of crimp neck vial) according to the slurry composition and injection pressure after internal slurry application to the target crimp neck vial, and Fig. 47 is a picture showing the side photograph (side photograph after internal application of crimp neck vial).

[0090] Figure 48 is a photograph (a photograph of the wall surface after cleaning during ion exchange inside a crimp neck vial) taken after heat treatment at 450°C for 16 hours in a glass vial with a coating film formed inside it using the method described above, and observed with a polarizer after removing the coating film.

[0091] Figure 49 is a graph showing the results of measuring the distribution of surface alkali concentration (side ion exchange concentration during internal ion exchange in a crimp neck glass vial) in a direction perpendicular to the ion exchange direction on the side of a glass vial after internal ion exchange and removal of the coating film using SEM-EDS, and is a picture inserting a photo of the side of the glass vial where the concentration measurement was performed.

[0092] Figure 50 is a graph showing the results of measuring the distribution of alkali concentration (bottom ion exchange concentration during ion exchange inside a crimp neck glass vial) in the direction of ion exchange depth by cutting off the bottom of a glass vial manufactured by the above-described method and using SEM-EDS, and is a drawing with the concentration measurement location inserted.

[0093] Figure 51 is a schematic diagram showing the brush coating method and the drainage coating method among the paste-based processes for forming a coating film inside a glass vial.

[0094] Figure 52 is a drawing showing photographs of a coating film after applying and drying a slurry composition with a different viscosity-improving agent content ratio to the inner wall of a glass vial, according to the slurry composition and application process.

[0095] Figure 53 is a photograph showing internal coating films made with slurry compositions having different viscosity-improving agent content ratios, which were subjected to ion exchange heat treatment at 450°C for 6 hours, then the coating films were washed and photographed by placing the glass vials on a surface light source.

[0096] Figures 54 and 55 are photographs of each specimen after drying of the coating film of a glass vial with the interior ion-exchanged using the dry paste method, after ion exchange, and after removal of the coating film (Figure 54 is a photograph of the coating film after drying, and Figure 55 is a photograph of the coating film removed after ion exchange).

[0097] Figure 56 is a drawing showing the shape of the inner coating film before and after ion exchange in a metal oxide slurry with added viscosity enhancer, with respect to the KNO3 content in the coating film and the ion exchange heat treatment temperature.

[0098] Figure 57 is a drawing showing a table for explaining the stress concentration area of ​​a vial.

[0099] Figure 58 is a schematic diagram showing the vial reinforcement area of ​​the existing ion exchange technology (schematic diagram of the existing ion exchange concept).

[0100] Figure 59 is a diagram illustrating the concept of position-selective ion exchange (a schematic diagram of the concept of position-selective ion exchange) and is a diagram illustrating several cases of additionally strengthening the stress concentration area of ​​the glass vial shown in the table of Figure 57.

[0101] Figure 60 is a drawing showing photographs of a specimen on which a coating film was formed using the method described above before and after ion exchange (photographs of a coating film before and after location-selective ion exchange).

[0102] Figure 61 is a drawing showing the naked eye and polarizing observation photographs (photos of a surface light source and polarizing photograph of a glass vial before and after position-selective ion exchange) after removal of the coating film of the position-selective ion exchange specimen.

[0103] Figure 62 is a drawing showing the results of measuring CS and DOL (CS, DOL of position-selective ion-exchange vials) of glass vials that were position-selectively ion-exchanged at 450°C for 16 and 2 hours, respectively, using FSM equipment.

[0104] Figure 63 is a photograph of interference wrinkles at each measurement location in a position-selective ion exchange glass vial.

[0105] Figure 64 is a schematic diagram showing the strengthened area for each case of position-selective ion exchange of a target vial for pressure testing.

[0106] Figure 65 is a drawing showing a case-by-case photograph of a coating film after drying of a location-selective ion exchange vial.

[0107] Figure 66 is a graph showing the CS and DOL (CS, DOL of position-selective ion exchange vials) measurement results of glass vials ion-exchanged at 500°C for 5 hours using FSM equipment. Figure 66 (a) is a graph showing the CS and DOL of Case 1 for each specimen, and Figure 66 (b) is a graph showing the CS and DOL of Case 4 for each specimen.

[0108] Figure 67 is a graph showing the average, maximum, and minimum values ​​of the pressure strength test results for each ion exchange case.

[0109] Figure 68 is a table showing the ion exchange area and ion exchange characteristic indices of glass vials subjected to pressure strength tests for each ion exchange case.

[0110] Below, with reference to the attached drawings, embodiments of the present invention are described in detail to facilitate easy implementation by those skilled in the art. However, the present invention can be implemented in various different forms and is not limited to the embodiments described herein. In the drawings, irrelevant parts have been omitted for clarity, and similar reference numerals have been used throughout the specification to indicate similar elements.

[0111] Throughout this specification, when a part is said to be "connected" to another part, this includes not only the case where it is "directly connected," but also the case where it is "electrically connected" or "indirectly connected" with another element in between.

[0112] Throughout this specification, when it is said that a member is located “on,” “above,” “upper,” “lower,” “lower” or “lower” another member, this includes not only cases where the member is in contact with the other member, but also cases where another member exists between the two members.

[0113] Throughout this specification, whenever a part is said to "include" a component, this does not mean that it excludes other components, but rather that it may include other components, unless otherwise specifically stated.

[0114] The present invention relates to a method for manufacturing a glass container by chemically strengthening it through dry ion exchange, and to a chemically strengthened glass container manufactured by this method. Specifically, the present invention relates to a chemically strengthened glass container in which a coating film is formed using a slurry containing metal oxide particles at room temperature and the dry strengthening is performed to impart location-selective ion exchange characteristics, and further, to an improved pressure-resistant characteristic.

[0115] According to one embodiment of the present invention, by utilizing a dry ion exchange, ion exchange uniformity, surface compressive stress, and diffusion depth comparable to those of the immersion method can be provided for Type I glass vials having a borosilicate composition. When performing dry ion exchange by spraying an alkali salt at a high temperature in the prior art, there is a problem in that the viscosity of the molten salt is low, causing the coating film to flow and the coating film thickness cannot be formed thicker than a certain level. In the present invention, a slurry is prepared by including an alkali salt, metal oxide particles, and a solvent, so that a thicker film can be formed compared to the KNO3 molten salt when forming the coating film, thereby enabling the provision of more alkali ions and controlling unnecessary flow of the molten salt to maintain the shape of the coating film. According to an embodiment of the present invention, peeling and flowing of the coating film including the metal oxide particles did not occur over a wide ion exchange temperature range, and it was confirmed that the surface compressive stress and diffusion depth, which are indicators of ion exchange characteristics, were at a level similar to that of the wet method. At this time, the mass of the dry coating film was approximately 0.15 g, which consumed approximately 4,000 times less starting material than the wet coating film of approximately 650 g.

[0116] In the case of glass containers where only the outer wall is asymmetrically chemically strengthened through wet and dry ion exchange, the pressure characteristics after ion exchange are the same or lower than those of unreinforced products because tensile stress is formed in the inner wall. This pressure reduction is expected to be resolved through two methods described below. The first is to additionally perform internal ion exchange to form compressive stress in the inner wall. The second is to introduce the concept of location-selective ion exchange to strengthen only the stress-concentrated area, thereby avoiding the formation of tensile stress in the central part of the inner wall.

[0117] The first method, which additionally performs internal ion exchange, has a disadvantage in that the chemical durability of the glass may be reduced by the alkali ions introduced to the glass surface during ion exchange. Considering this, the surface alkali concentration that does not significantly reduce the chemical durability of the glass can be determined as the maximum ion exchange concentration. At this time, the minimum ion exchange concentration is determined to be a level that does not form tensile stress on the internal surface. In the case of the dry method developed in the present invention, the surface concentration can be actively controlled by controlling process factors such as the thickness of the coating film and the slurry composition ratio during ion exchange, thereby satisfying the above conditions and providing a glass container product with improved pressure resistance without a significant reduction in chemical durability.

[0118] According to one embodiment of the present invention, in order to manufacture glass that improves pressure resistance by forming compressive stress on the inner wall without significantly reducing the chemical durability of the glass container when simultaneously reinforcing the outer wall and inner wall of the glass container, the following conditions must be satisfied. First, in order not to reduce the chemical durability after ion exchange, the alkali concentration on the glass surface after ion exchange may be 0.75 or less, and preferably 0.5 or less. Second, as a minimum condition for relieving the tensile stress on the inner wall, the surface alkali concentration ratio or CS ratio of the inner wall and outer wall must be at least It must have a value of .

[0119] When introducing the second method, site-selective ion exchange, it can be successfully performed if the stress concentration area is reinforced without forming tensile stress in the central part of the inner wall, masking can be easily formed and removed during the coating process, and the site-selectively formed coating film maintains its shape during ion exchange heat treatment and does not flow into the unreinforced area.

[0120] Accordingly, in one embodiment of the present invention, an alkaline salt solution containing metal oxide particles was applied to a portion of the surface of a glass vial at room temperature. For reference, the unreinforced area was masked with a commercial 3M tape, and was easily removed after drying. As a result of the ion exchange heat treatment process on the glass vial to which the above-described location-selectively applied film was applied, it was confirmed that the coating film did not flow unnecessarily and maintained its shape, and that the chemical strengthening characteristics were different depending on the location. In this way, the present invention can selectively ion-exchange an alkaline salt slurry containing metal oxide onto the surface of a glass container, and based on this, the pressure-resistant characteristics of the glass container can be improved through external application alone.

[0121] The glass vials used in the examples of the present invention are glass with a Type I borosilicate composition and have the same specifications and shape as shown in Fig. 1, and are referred to in the examples below by the nomenclature written in Fig. 1. However, the present invention is not limited to the glass vials described above, and can be applied to products in the form of glass containers having an alkali-containing silicate composition.

[0122] In one or more embodiments, the surface compressive stress (CS) and diffusion depth (DOL) measured were measured using FSM. The FSM was measured at the outer wall of the glass vial body, and the CS and DOL were measured at each position while rotating the vial by 90°, and the average was plotted. Additionally, CS or DOL obtained using other optical or chemical measuring devices for measuring surface compressive stress and diffusion depth, including FSM, can also be utilized in the present invention.

[0123] <Example>

[0124] 1. Dry ion exchange outside the glass vial

[0125] 1.1. Spray process dry method external ion exchange

[0126] In this example, a coating film was formed over the entire external area of ​​the vial using a spray process utilizing alkaline salt-containing metal oxide particles, and then dry ion exchange was performed to evaluate the ion exchange characteristics of the glass vials manufactured. In this case, the glass vials used for ion exchange were Type I vials having a borosilicate series composition, and each vial had a different shape and size.

[0127] Before proceeding with all the examples of the present invention, the viscosity of the slurry requires an optimal viscosity depending on the process method, and since it can determine the uniformity of the final formed coating film, the viscosity of the target slurries utilized in the present invention was confirmed. Fig. 2 shows the viscosity measurement results of the slurry composition without the viscosity improver utilized in each example of the present invention with respect to the content ratio of TiO2 in the slurry. At this time, the slurry was prepared by adding KNO3:TiO2 to 100 ml of water solvent at molar ratios of 80:20, 66:34, 57:43, 50:50, and 44:56. The viscosity of the prepared slurries was measured at a spindle speed of 100 rpm using a rotational viscometer. According to Fig. 2, it was confirmed that viscosity control was possible from a minimum of about 13 mPa·s to a maximum of about 750 mPa·s in the composition range described above simply by changing the KNO3:TiO2 molar ratio without a viscosity control enhancer, and it was confirmed that the viscosity increased with an increase in the TiO2 content within the composition range of the slurry used in this experiment. Based on the examples described below, when the viscosity applied uniformly for each of the outer wall and inner wall applications was judged, the viscosity of the slurry for outer wall application in Example 1.1 was confirmed to be about 43 mPa·s, and when judged in a wide range, it can be judged to be at least about 13 mPa·s or more and 220 mPa·s or less. In Example 2.5, for inner wall application, it was judged that the application was uniform when it was about 220 mPa·s or more and about 750 mPa·s or less, and the coating film was stably maintained after heat treatment.

[0128] The slurry was prepared by adding KNO3:TiO2 in a molar ratio of approximately 66:34 to 100 ml of water solvent. The slurry was sprayed from a distance of 1 m at room temperature and 60% humidity under a pressure of 8 bar to form a coating film on the surface of a glass vial, and then dried under the same temperature and humidity conditions. At this time, the viscosity of the slurry was approximately 43 mPa·s. In order to form a coating film on the entire area of ​​the glass vial, the spraying and drying processes were repeated a total of 4 times by rotating the vial 90° each time.

[0129] Additionally, as an example of producing a slurry of a different composition, slurries produced by adding KNO3:TiO2 in a molar ratio of about 80:20 and 57:43 to 100 ml of water solvent were applied to a glass vial using the same coating method as above. At this time, the viscosities of the slurries were about 13 mPa·s and about 220 mPa·s, respectively, and it was confirmed that the slurry spraying was completed without clogging the spray gun within the corresponding viscosity range, confirming that the spray coating process for the outer wall of the glass container can be performed within the corresponding viscosity range. However, if the viscosity is excessively low, the thickness of the coating film may be reduced, and if the viscosity is excessively high, the probability of the coating film being formed unevenly may increase. Therefore, based on the above, it was confirmed that the optimal spraying condition in the present invention in terms of the coating film thickness and uniformity was a viscosity of about 43 mPa·s, and the examples described below were all performed when the viscosity was 43 mPa·s.

[0130] Figure 3 shows the results of applying a metal oxide particle-based alkaline salt slurry to three glass vials of different specifications and shapes using a room-temperature spray process. After drying, the coating film was visually confirmed to be uniform, and it was confirmed that uniform application was possible not only on the wall and bottom areas of the body area where there is curvature, but also on shoulder, flange, and neck (or screw) areas with complex shapes.

[0131] Figure 4 is a drawing showing the change in the shape of the coating film before and after ion exchange when two types of glass vials with different specifications and shapes were placed in an electric furnace while standing and ion exchange was performed at 450, 500, and 550°C for 16, 5, and 2 hours, respectively. Even though the heat treatment was performed above the liquidus temperature of the KNO3 salt, no dripping or unevenness of the coating film was observed in any specimen, and limited peeling of the coating film occurred in some specimens under the 550°C heat treatment condition.

[0132] Figure 5 depicts the morphology of glass vials after ion-exchange at 450, 500, and 550°C for 16, 5, and 2 hours, respectively, after removal of the coating. The coating was easily removed with running tap water after ion exchange, and no residue was observed upon subsequent washing with purified water. Furthermore, no morphological changes due to external ion exchange were observed after removal of the coating.

[0133] Figure 6 shows photographs of the shapes of glass vials that were ion-exchanged at 450, 500, and 550°C for 16, 5, and 2 hours, respectively, after the coating was removed, observed through a polarizer. The polarizer consists of a white light source and two polarizing films. The glass vials were placed between the two polarizing films, and observation results confirmed that no defects such as uneven stress distribution, contamination, or irregular shape changes occurred under all heat treatment temperature conditions.

[0134] Figure 7 is a photograph showing the CS and DOL measurement results of glass vials ion-exchanged at 400, 450, 500, and 550°C for 24, 9, 5, and 3 hours, respectively, using FSM equipment. The type of glass vial being measured here is a screw neck (5 ml), and each specimen was measured a total of 8 times, and the average value was calculated. The measurement results confirmed that CS decreased as the ion-exchange temperature increased due to stress relaxation.

[0135] Figure 8 shows the results of measuring the alkali concentration distribution in the direction of the ion exchange depth in the body region of glass vials ion-exchanged at 400, 450, 500, and 550°C for 24, 9, 5, and 3 hours, respectively, using SEM-EDS. The normalized concentration shown in Figure 8 was calculated as the ratio of the ion-exchanged K concentration to the total alkali concentration (Na + K), and it was confirmed that the DOL measured in Figure 7 and the actual diffusion depth were at similar levels.

[0136] Figures 9 and 10 are graphs showing the CS and DOL measurements of glass vials ion-exchanged at 450, 500, and 550°C for 16, 5, and 2 hours, respectively, using FSM equipment. In this case, glass vials with a crimp neck (5 ml) and a screw neck (5 ml) were used. No significant difference in CS and DOL was observed between the two types of vials under the same ion-exchange conditions, and similar to the results described above, a tendency for CS to significantly decrease due to stress relaxation was confirmed as the ion-exchange temperature increased.

[0137] Figure 11 shows the results of measuring the alkali concentration distribution in the ion exchange direction by position in a glass vial ion-exchanged at 500°C for 5 hours using SEM-EDS. In order to confirm the ion exchange characteristics in the area where stress measurement using FSM was impossible, the concentration distribution was measured in the ion exchange depth direction in each area. The measurement locations were named bottom, body, neck, screw (bottom), and screw (upper), and these measurement locations are illustrated in Figure 12. It was confirmed that the normalized alkali concentration at all locations had a distribution similar to that of the body area, and based on this, it can be expected that the ion exchange characteristic index will be similar to the value measured in the body area even in areas with complex shapes.

[0138] Fig. 13 shows the results of measuring the hardness of glass vials that were ion-exchanged or not ion-exchanged at 450, 500, and 550 ℃ for 16, 5, and 2 hours, respectively, using a Vickers hardness tester, and Fig. 14 is a drawing showing the locations in the glass vials where the Vickers hardness was measured. The indentation load and time for measuring the Vickers hardness were 200 gf and 25 seconds, respectively, and the average value was derived by measuring 5 times in the body area of ​​each glass vial. In the case of glass vials ion-exchanged by the dry method, it was confirmed that there was a significant hardness improvement effect after ion-exchange, and in the case of high-temperature ion-exchange (i.e., 550 ℃), a hardness decrease tendency related to the decrease in CS caused by the stress relaxation phenomenon was confirmed.

[0139] 1.2 Spray process dry ion exchange process coating film stability confirmation

[0140] In this example, a coating film was formed over the entire external area of ​​the vial using a spray process utilizing alkaline salt-containing metal oxide particles, and then dry ion exchange was performed to fabricate the glass vial. This was done to confirm the thermal stability of the coating film against temperature changes felt by the target glass vial during the ion exchange heat treatment process. In this case, the glass vials used for the ion exchange were both Type I vials having a borosilicate series composition, and two types of screw vials of different sizes were utilized.

[0141] The slurry was prepared by adding KNO3:TiO2 in a molar ratio of approximately 66:34 to 100 ml of water solvent. The slurry was sprayed from a distance of 1 m at room temperature and 60% humidity under a pressure of 8 bar to form a coating film on the surface of a glass vial, and then dried under the same temperature and humidity conditions. In order to form a coating film over the entire area of ​​the glass vial, the vial was rotated 90° and the spraying and drying process was repeated a total of 4 times. At this time, the viscosity of the slurry was approximately 43 mPa·s under the measurement condition of a spindle speed of 100 rpm of a rotational viscometer.

[0142] During the ion exchange step, the temperature change rate was controlled by inserting or not inserting insulation inside the electric furnace. To measure the temperature, a thermocouple consisting of a pair of metal wires was inserted inside the electric furnace, and the tips of the thermocouple were positioned so that they directly contacted the surface of the vial. The temperature felt at the actual surface of the vial was recorded over time, and the temperature change rate was derived by differentiating this with respect to time.

[0143] Fig. 15(a) is a graph showing the temperature measurement results of the vial surface when the electric furnace is not loaded with insulation, and Fig. 15(b) is a graph showing the temperature measurement results when the electric furnace is loaded with insulation, and when the set temperatures of the electric furnace are 450, 500, and 550°C, respectively. Here, the temperature change section can be broadly divided into a temperature increase section to prevent initial thermal shock and a heat treatment section in which ion exchange occurs in the later stage, and the boundary points where the temperature increase section and the heat treatment section are divided are roughly marked in the drawing. In the case of the electric furnace used in the example of the present invention, the temperature overshoot tended to decrease as the set temperature increased, and it was confirmed that the temperature overshoot could be alleviated by additional loading of insulation. The heat treatment conditions of the present example can be broadly divided into a temperature increase section and a temperature maintenance section. However, temperature overshoots occurred repeatedly over a short time span relative to the overall heat treatment time across all time ranges, indicating repeated heating, holding, and cooling cycles with very high temperature change rates. Therefore, a skilled practitioner could interpret these repeated overshoots as representing dynamic temperature change intervals.

[0144] Fig. 16 is a graph that derives the temperature change rate by differentiating the electric furnace temperature measurement results of Fig. 15 with respect to time. Fig. 16 (a) shows the case when no insulation is loaded, and Fig. 16 (b) shows the case when insulation is loaded. Here, as in Fig. 15, the boundary points of the heating section and the heat treatment section are roughly marked. At this time, an upper envelope is simultaneously drawn on the graph in order to visually compare the maximum temperature change rate for each heating and cooling cycle. As described above, when no insulation is loaded, the maximum temperature change rate was confirmed to be less than about 270 ℃ / min at all set temperatures, but when insulation is loaded, the corresponding value was confirmed to be less than 180 ℃ / min at all set temperature conditions. Specifically, according to the results shown in Figs. 16(a) and (b), the maximum instantaneous temperature change rate in the temperature increase step within about 45 minutes from the start of the heat treatment was confirmed to be less than about 270 ℃ / min without insulation and about 180 ℃ / min with insulation. In addition, in the temperature maintenance step where the ion exchange heat treatment occurs, it was confirmed to be less than about 100 ℃ / min without insulation and about 70 ℃ / min with insulation.

[0145] Figure 17 is a drawing showing the morphology of the coating film immediately after ion exchange when two glass vials of different shapes were placed upright in an electric furnace without insulation and ion exchange was performed at 450°C and 500°C for 4 hours and 2 hours, respectively. Despite the relatively low temperature and short heat treatment conditions, cracking and peeling of the coating film were confirmed to have occurred in all specimens.

[0146] Figure 18 depicts the post-ion exchange appearance of vial specimens that were dry ion-exchanged at 450°C and 500°C for 13 and 5 hours, respectively, while being loaded into an electric furnace with insulation. The coating film was inspected after ion-exchange heat treatment, confirming that it was stably attached to the vial surface without any cracks or peeling during the ion-exchange process. After washing the coating film with running water, it was confirmed that the surface remained clean, with no surface contamination or unevenness.

[0147] Based on the results of FIGS. 17 and 18, when a spray-based dry ion exchange coating film was formed and heat-treated using a slurry having a viscosity of about 43 mPa·s used in the examples of the present invention for a glass vial having a high curvature radius of about 9 mm at the wall, it was confirmed that the coating film was uniformly maintained without defects such as cracks or peeling even when the maximum temperature change rate during the heat treatment was about 180 ℃ / min. Based on these results, the excellent thermal stability of the metal oxide-based coating film used in the examples of this invention was confirmed.

[0148] 1.3. Comparison of wet ion exchange methods

[0149] This example was conducted to compare the ion exchange characteristics of glass vials chemically strengthened by wet and dry methods. For wet ion exchange, the glass vial was immersed in a molten salt having a mass of approximately 650 g and a composition of 100% KNO up to the neck position, so that only the outer wall was in contact with the molten salt, and strengthening was performed. The wet heat treatment consisted of a main heat treatment for immersing the glass and pre- and post-heat treatments to prevent thermal shock before and after the main heat treatment. The pre- and post-heat treatments were each performed for 30 minutes at the same temperature conditions as the main heat treatment. The main heat treatment was performed at 450, 500, and 550°C for 16, 5, and 2 hours, respectively. For comparison with the dry method, similar ion exchange temperatures and times as in Example 1.1 were selected.

[0150] Figure 19 illustrates macroscopic and polarimetric photographs of glass vials subjected to wet ion exchange at 450, 500, and 550°C for 16, 5, and 2 hours, respectively. The results of the wet external ion exchange confirmed the absence of uneven stress distribution and irregular shape changes.

[0151] Fig. 20 is a photograph showing the results of measuring CS and DOL of glass vials ion-exchanged in a wet manner at 450, 500, and 550°C for 16, 5, and 2 hours, respectively, using FSM equipment. In this case, a crimp neck (5 ml) was used as the glass vial. When compared with the CS and DOL of the glass vials ion-exchanged in a dry manner as shown in Fig. 9 of Example 1.1, no significant difference in CS and DOL beyond the margin of error was observed between the wet and dry ion-exchange methods under the same ion-exchange conditions. For reference, the coating film mass of the dry ion-exchange method was about 0.15 g per specimen, which confirmed that it could provide ion-exchange characteristic indices similar to those of the wet method under similar ion-exchange conditions while using about 4,000 times less starting materials compared to the wet method.

[0152] 1.4. Confirmation of reproducibility of external ion exchange using the dry spray process

[0153] To verify the process reproducibility of the dry glass vial ion exchange described in Example 1.1, 12 specimens were prepared for each ion exchange condition. In this reproducibility verification experiment, the glass vials were all crimp neck (5 ml) glass vials, and the slurry was prepared by adding KNO3:TiO2 to 100 ml of water solvent at a molar ratio of approximately 66:34. The slurry was sprayed from a distance of 1 m at room temperature and 60% humidity at a pressure of 8 bar using a general gravity spray gun to form a coating film on the surface of the glass vial, and then dried under the same temperature and humidity conditions. At this time, the viscosity of the slurry was approximately 43 mPa·s under the measurement condition of a spindle speed of 100 rpm of a rotational viscometer. To form a coating film over the entire area of ​​the glass vial, the vials were rotated 90° each time, and the spraying and drying processes were repeated four times in total. After drying the coating film, the ion exchange heat treatment was performed at 450 °C for 16 and 2 hours, respectively. All other processes except the ion exchange heat treatment process conditions were carried out in the same manner as in Example 1.1.

[0154] Figures 21 to 23 show photographs of each specimen after drying of the coating film of a glass vial subjected to ion exchange by the dry method, after ion exchange, and after removal of the coating film. Here, the specimens ion-exchanged at 450°C for 16 hours were assigned specimen numbers 1-12, and the specimens ion-exchanged at 450°C for 2 hours were assigned specimen numbers 13-24. Figure 21 shows the shape of the coating film after drying, and it can be confirmed with the naked eye that the coating film was formed uniformly in a total of 24 specimens. Figure 22 shows the shape of the coating film after ion exchange, and it can be confirmed with the naked eye that there was no dripping or shape change of the coating film under both ion exchange conditions. Finally, Figure 23 shows the results of placing the specimens with the coating film removed after ion exchange on a surface light source and visually inspecting them, and it can be confirmed that no unevenness or defects occurred in any specimens that underwent the two ion exchange heat treatments.

[0155] Figure 24 (a) shows the CS and DOL measurement results of glass vials ion-exchanged at 450°C for 16 hours using FSM equipment, and Figure 24 (b) shows the CS and DOL measurement results for each specimen of glass vials ion-exchanged at 450°C for 2 hours. At this time, CS and DOL were measured a total of 12 times for each specimen and the average values ​​were calculated. When ion-exchanged at 450°C for 16 hours, CS and DOL were measured to be approximately 250 MPa and 33 μm, respectively, and when ion-exchanged at 450°C for 2 hours, CS and DOL were measured to be approximately 300 MPa and 12 μm, respectively.

[0156] 1.5. Optimization of slurry rheological properties for paste processes

[0157] In this example, prior to fabricating a dry ion-exchanged glass vial using a paste-based process utilizing metal oxide particles, the goal was to optimize the paste composition to form a uniform coating film. The coating method employed may include a dip coating method, in which the target glass vial is immersed in the paste and then drawn out at a constant speed to form a coating film, as well as a brush coating method, in which the paste is applied directly to the glass surface using a brush.

[0158] Figure 25 is a schematic diagram illustrating the two coating processes described above. At this time, to secure an optimal viscosity corresponding to the shear rate for each process, the mixing ratio of alkali salts and metal oxide particles in the slurry composition can be changed, or a viscosity enhancer can be employed.

[0159] To implement the method and one embodiment provided herein, a process for applying a slurry to a specific, partial, or entire location of a glass container is required. At this time, in order to form a coating film on the surface of the glass container, processes such as spray coating, dip coating, and brush coating, as well as the spray coating corresponding to Examples 1.1 to 1.4, can be utilized. Among typical coating methods, the required viscosity increases in the order of spray coating, dip coating, and brush coating, while the corresponding shear rate tends to decrease. As such, since the required viscosity and shear rate vary depending on the coating process, control of the rheological properties of the slurry or paste is essential for applying a specific coating process.

[0160] Additionally, according to one embodiment of the present invention, in the case of a glass container having a complex three-dimensional shape and a sharp curvature at the connection of each component, when applying a conventional room temperature coating-based dry ion exchange technology, peeling or cracking of the coating film may be induced during the process due to a sharp temperature change in the part having the curvature. Such a defect may result in non-uniform ion exchange, and to prevent this, as in Example 1.2, the maximum temperature change rate may be controlled to suppress a sharp temperature change at the interface between the coating film and the glass surface, or the relative content or viscosity of each component in the slurry may be controlled to improve the thermal stability of the coating film.

[0161] Figure 26 illustrates an example of measuring the viscosity of a slurry based on metal oxide particles of the present invention. The slurry was prepared by mixing KNO3:TiO2 in a molar ratio of approximately 68:32 in 100 ml of water solvent and then adding a viscosity enhancer. Each slurry was prepared with a different type and content of the viscosity enhancer. The viscosity of the prepared metal oxide slurry was measured by varying the rotation speed of the spindle using a rotational viscometer while maintaining the temperature at a constant 50°C. The measurement results confirmed that the viscosity of the slurry could be controlled by varying the content of the viscosity enhancer, and the viscosity of the slurries used in the present invention showed a typical shear thinning behavior in which it decreased with increasing shear rate. The shear thinning phenomenon was confirmed to occur to different degrees depending on the type of viscosity enhancer. Here, viscosity enhancer A, which exhibits a more pronounced shear thinning phenomenon, is considered more advantageous in terms of process applicability. The viscosity that can be uniformly applied to the dip coating adopted in Example 1.6 described later is indicated by the box shape in the graph, and the corresponding viscosity range was confirmed to be approximately 450-1600 mPa·s based on the shear rate of the coating process. When a slurry with a viscosity of 43 mPa·s, which is excessively lower than the corresponding viscosity range, was used in the coating step of the dry ion exchange Example 1.6 based on the dip coating method described later, the low viscosity caused the coating film to flow down in the direction of gravity during drying, resulting in unevenness, and the ion exchange characteristics tended to deteriorate due to the thin coating film thickness. On the other hand, when an excessively high viscosity of 2600 mPa·s was used, it was confirmed that the thickness fluctuated severely in some areas due to the high viscosity, resulting in local unevenness.Based on these results, it was determined that in order to successfully perform the dip coating process on a container glass, the viscosity of the slurry must be manufactured at the level of 450-1600 mPa·s. If the viscosity of the slurry is lower or higher than that range, the uniformity of the coating film deteriorates, and as a result, the uniformity of ion exchange also deteriorates.

[0162] Fig. 27 is a photograph showing the appearance after drying of a coating film formed by dip coating using slurries with different viscosities, and Fig. 28 is a photograph showing the result of observing the cross-section of the coating film after drying is complete using an optical microscope. Slurry composition A was prepared by adding KNO3:TiO2 in a molar ratio of about 66:34 to 100 ml of water solvent, and composition B was prepared by adding KNO3:TiO2 in a molar ratio of about 68:32 to 100 ml of water solvent, and then adding a viscosity enhancer. Referring to Fig. 2, which is the result of measuring the viscosity of each slurry composition, the viscosity of each prepared slurry A is about 43 mPa·s, and the viscosity of each prepared slurry B is about 2600 mPa·s. Using the two types of slurries produced, a coating film was formed on the outer surface of a glass vial by dip coating at a pulling speed of 10, 1, and 0.1 mm / s, respectively, at room temperature and 60% humidity, and then dried in a constant temperature and humidity chamber at a temperature of 65°C and a humidity of 20%.

[0163] According to the results in Fig. 27, in the case of Composition A with a relatively low viscosity (approximately 43 mPa·s), the coating film flowed down during the drying process, resulting in local thickness unevenness on the coating surface. On the other hand, in the case of Composition B with a high viscosity (approximately 2600 mPa·s), as the fluidity of the slurry decreased, the thickness deviation of the coating film at each location increased, resulting in an overall uneven film formation. This trend was also confirmed in the optical microscope cross-sectional observation results in Fig. 28. In the case of Composition A, the coating film thickness was formed relatively thinly, generally in the order of several tens of μm, and in the case of Composition B, a coating film at the order of several hundred μm was formed. However, even within the same specimen, the thickness deviation was large depending on the location, and the uniformity of the coating film could not be secured. In consideration of these results comprehensively, in order to form a uniform coating film on the surface of a glass vial using the dip coating method, it was confirmed that it is essential to avoid cases where the viscosity of the slurry is excessively low or high, and to select an appropriate viscosity range as mentioned in the paragraph below.

[0164] Fig. 29 is a picture showing the coating film after heat treatment at 450 ℃ for 16 hours for the specimens shown in Fig. 27, and Fig. 30 is a picture showing the FSM measurement results of the corresponding specimens. According to Fig. 29, in slurry composition A, excessive flow of the coating film did not occur after ion exchange, but in slurry composition B, a shape change due to flow of the coating film occurred in the excessively coated area. According to Fig. 30, ion exchange characteristic indices were measurable in all specimens, confirming that ion exchange was completed. In the case of slurry composition A, it was confirmed that the weight of the coating film decreased as the pulling speed decreased, and the CS tended to decrease. On the other hand, slurry composition B had a relatively high viscosity, so there was no clear correlation between the pulling speed and the weight of the coating film, and the CS measurement value was also measured at a similar level regardless of the coating conditions.

[0165] Fig. 31 is a drawing showing the shape of the coating film before and after heat treatment under heat treatment conditions corresponding to 500°C in Fig. 16 (a), which is a condition without insulation material and where the maximum instantaneous temperature change rate reaches approximately 270°C / min, to confirm the thermal stability of the paste-based coating film including the viscosity improver. The slurry was prepared in a KNO3:TiO2 molar ratio of approximately 68:32 in 100 ml of water solvent, and was prepared by adding the viscosity improver. At this time, according to Fig. 26 (a), the viscosity of the slurry is approximately 650 mPa·s under the measurement condition of a spindle speed of 100 rpm in a rotational viscometer. The ion exchange heat treatment was performed at 500°C for 5 hours, and it was confirmed that no unevenness such as cracking or peeling of the coating film occurred despite the temperature change reaching 270°C / min during the ion exchange. These results suggest that appropriate control of the viscosity of the slurry composition is very effective in improving not only the uniformity of the coating film but also its excellent thermal stability under conditions of rapid temperature changes.

[0166] In the dry ion exchange case based on the spray process of Example 1.2, when the viscosity of the slurry corresponding to the application process was about 43 mPa·s, when the maximum temperature change rate was controlled to less than about 180 ℃ / min, no peeling of the coating film occurred, whereas in the paste including the viscosity improver of this example, when the corresponding viscosity was about 650 mPa·s, no peeling of the coating film occurred even under conditions of rapid temperature change rates of up to 270 ℃ / min, confirming that the viscosity control of the slurry also affected the improvement of the thermal stability of the coating film. In addition, as shown in FIGS. 15 and 16, in the actual temperature change section, the instantaneous maximum temperature change rate fluctuates up to 270 ℃ / min in the temperature increase section or up to 180 ℃ / min under the insulation loading condition, and is composed of a periodic dynamic temperature section in which temperature increase and decrease are repeated. Therefore, it is believed that a process in which the temperature change rate over time is actively controlled within the temperature change rate range described above can be applied depending on the slurry composition. For example, the example of the temperature section illustrated in Example 1.2 of the present application consists of a two-step structure of a heat treatment step (ion exchange heat treatment step) after temperature elevation, but when the actual temperature change section is divided into smaller time ranges, as shown in FIGS. 15 and 16, a series of processes consisting of temperature elevation, temperature maintenance, and temperature reduction are repeatedly performed, and it was confirmed that the coating film formed by the dry method is stably maintained during the process. Considering these characteristics, a person skilled in the art can easily derive that an actively controllable heat treatment process can be implemented by adding a cooling step or subdividing the temperature elevation and heat treatment processes in addition to the process in which the temperature elevation and ion exchange heat treatment are performed as illustrated in the examples of the present application.

[0167] 1.6. Paste process dry method external ion exchange

[0168] In this example, a paste containing an alkali salt, metal oxide particles, and a viscosity enhancer was used on the external area of ​​the vial, and a film was formed by dip coating or brush coating during the paste process, followed by dry ion exchange, to evaluate the ion exchange characteristics of the manufactured glass vials. In this case, the glass vials used for the ion exchange were both crimp neck (10 ml) glass vials having a borosilicate series composition.

[0169] The paste was prepared by adding a viscosity enhancer and a KNO3:TiO2 molar ratio of about 68:32 to 100 ml of water solvent. At this time, the viscosity range of the slurry is about 450 mPa·s to 650 mPa·s for the A series, and 650 mPa·s to 1600 mPa·s for the B composition series. The prepared paste was dip-coated to form a coating film on the outer surface of a glass vial at different drawing speeds, and then dried in a constant temperature and humidity chamber at a temperature of 65 ℃ and a humidity of 20%.

[0170] Figure 32 is a photograph showing the dried coating film applied by the dip coating method. Here, paste compositions A and B have different types of viscosity enhancers, and a larger number means an increase in the content of the viscosity enhancer. For each slurry composition, application was performed under the conditions of a withdrawal speed of 1 mm / s and 5 mm / s. At this time, it was confirmed that the coating was applied without any uncoated area on the outer wall side and bottom of the glass vial at all withdrawal speeds. However, since viscosity enhancer B did not have a distinct shear thinning phenomenon, the coating film flowed during drying regardless of the amount added and the withdrawal speed, despite the relatively high overall viscosity.

[0171] Fig. 33 (a) is a photograph showing the results of measuring CS and DOL of a glass vial ion-exchanged at 450 ℃ for 6 hours using FSM equipment. At this time, each specimen was measured a total of 8 times and the average value was calculated. As a result of the measurement, no significant change was confirmed in CS and DOL depending on the content of viscosity improver in the paste or the change in the drawing speed. Fig. 33 (b) is a photograph showing the CS X DOL value derived by multiplying the measured CS and DOL with respect to the thickness of the coating film measured under each process condition. It was confirmed that the CS X DOL value tended to increase in proportion to the weight of the coating film, and it was confirmed that the increase in the value tended to slow down when the weight of the coating film exceeded a certain level.

[0172] 1.7. Confirmation of reproducibility of external ion exchange in the paste process dry method

[0173] In order to confirm the reproducibility of the dry ion exchange process utilizing the paste-based coating method described in Example 1.4, 24 specimens were produced under specific ion exchange conditions. In this reproducibility confirmation experiment, crimp neck (10 ml) glass vials were used as the target, and the paste was prepared by adding a viscosity enhancer to a 100 ml water solvent at a molar ratio of approximately 68:32 based on KNO3:TiO2, and the paste was drawn at a drawing speed of 5 mm / s at room temperature and 60% humidity to form a coating film on the surface of the glass vial, and then dried in a constant temperature and humidity chamber at 65°C and 20% humidity. At this time, the viscosity of the slurry was approximately 650 mPa·s under the measurement condition of a spindle speed of 100 rpm of a rotational viscometer. After drying the coating film, the ion exchange heat treatment was performed at 450°C for 16 hours.

[0174] Figures 34 to 36 show photographs of specimens after drying of the coating film of a glass vial ion-exchanged in a paste process-based dry method, after ion exchange, and after removal of the coating film. Here, the specimens were numbered 1 to 24. Figure 34 shows the shape of the coating film after drying, and it can be confirmed with the naked eye that the coating film was formed uniformly in a total of 24 specimens. Figure 35 shows the shape of the coating film after ion exchange, and it can be confirmed with the naked eye that there was no dripping or shape change of the coating film under the corresponding ion exchange conditions. Finally, Figure 36 shows the results of visually inspecting specimens with the coating film removed after ion exchange by placing them on a surface light source. At this time, it was confirmed that no unevenness or defects occurred in any specimens that underwent ion-exchange heat treatment at 450°C for 16 hours when using a slurry with a viscosity of approximately 650 mPa·s.

[0175] 1.8 Case study of external ion exchange characteristic control using a dry paste process

[0176] In this example, the possibility of controlling ion exchange characteristics by adjusting the composition of the slurry was verified. The glass composition utilized for ion exchange was a crimp neck (10 ml) glass vial containing a borosilicate glass composition. All other processes in the dry paste process, except for the slurry composition, were identical to those in Example 1.5.

[0177] Slurries were prepared by adding a viscosity enhancer to 100 ml of water solvent, and four types were prepared with KNO3:TiO2 molar ratios of about 24:76, about 11:89, about 6:94, and about 3:97. The prepared pastes were applied to the glass surface by dip coating at a pulling speed of 5 mm / s at room temperature and 60% humidity, and then dried in a constant temperature and humidity chamber at 65°C and 20% humidity. The ion exchange heat treatment was performed under three conditions: 500°C for 5 hours, 450°C for 6 hours, and 450°C for 16 hours, respectively. At this time, the viscosity of the slurries was not measured, but the slurries with a viscosity of about 650 mPa·s and the content of the viscosity enhancer were added in the same manner.

[0178] Figure 37 is a photograph depicting the appearance of the coating film before and after ion exchange according to each slurry composition and heat treatment condition. Regardless of the relative KNO3 content, the coating film formed by dip coating had a uniform appearance, and it was confirmed that the coating film was stably maintained without unnecessary flow, peeling, or cracking after ion exchange.

[0179] Figure 38 is a graph showing the ion exchange characteristic indices according to ion exchange heat treatment conditions with respect to the relative KNO3 content. It was confirmed that CS control was possible under three different ion exchange conditions. In all heat treatment conditions, CS showed a behavior of increasing proportionally to the relative KNO3 content, and it was confirmed that DOL was more greatly affected by the heat treatment conditions regardless of the relative KNO3 content. In particular, the results can be utilized in selecting the paste composition for the inner wall ion exchange described later in Example 2, and specifically, by controlling the relative content of ion-exchanged ions on the glass surface, chemical durability and mechanical property enhancement effects can be secured in a balanced manner.

[0180] 2. Dry ion exchange inside a glass vial

[0181] 2.1. Overview of ion exchange inside a glass vial

[0182] In the case of prior art techniques that only exchange ions on the outside of a glass vial, there is a disadvantage that the internal pressure characteristics are similar to or reduced compared to unreinforced glass vials, and this phenomenon occurs due to the formation of tensile stress on the inner wall of the glass vial. The above-mentioned problem can be solved by additionally performing internal ion exchange to remove the tensile stress formed on the inner wall of the glass vial. There is a disadvantage that the chemical durability of the glass may be reduced due to the ions introduced to the glass surface during this internal ion exchange. Taking this into consideration, the surface concentration that does not reduce the chemical durability of the glass can be determined as the maximum concentration. In this approach, the internal ion exchange can have a lower alkali surface concentration than the external ion exchange, and the condition that does not form tensile stress on the inner surface will be the minimum condition for the internal ion exchange. The advantage of the metal oxide slurry-based dry method developed in this invention is that the degree of ion exchange can be actively controlled for each position of the glass when an ion exchange gradient is introduced through process condition control (coating film thickness, slurry composition ratio, etc.), and by utilizing this, it is expected that glass vials with improved pressure characteristics can be manufactured without significant reduction in chemical durability.

[0183] 2.2 Maximum ion exchange concentration during internal ion exchange

[0184] It is well known that the chemical durability of various alkali-containing silicate glasses varies depending on the type of alkali ion contained. In general, sodium-containing glasses are known to have superior chemical durability compared to potassium-containing glasses (A. Abdelouas et al., "Chemical Durability of Glasses," in Springer Handbook of Glass, Vol. 5, Edited by JD Musgraves et al., Springer, (2019) p. 409), and it has been reported that chemical durability decreases in the order (Li > Na > K > Rb > Cs) (Ref. 2). Some literatures have reported that the mixed-alkali effect exists, with maximum chemical durability at 20-25% of the total alkali concentration (MF Dilmore et al., J. Am. Ceram. Soc. 61 (1978) 9), and that there is no significant decrease in chemical durability up to 75% (X. Wang et al., J. Mater. Sci. 52 (2017) 8986). In commercial Type 1 borosilicate glass, excellent chemical durability has been reported when the K content is 4.3 and 17.2% of the total alkali concentration (S. Pagnelo, O. Pinato, PDA J. Pharm. Sci. Tech. 74 (2020) 185).

[0185] Therefore, based on the above literature review results, it is judged that by utilizing the characteristics of the dry method to control the surface K concentration below a certain level during ion exchange, a significant decrease in chemical durability can be prevented, and in some cases, chemical durability can also be improved.

[0186] 2.3. Minimum ion exchange concentration during internal ion exchange

[0187] Figure 39 is a simplified schematic diagram of the stress distribution during double-sided asymmetric ion exchange. In this case, the DOL on the outer and inner walls are identical, but the CS is different during asymmetric ion exchange. In this case, the magnitude of the internal tensile stress can be expressed by the following mathematical equation (1).

[0188] [Mathematical Formula 1]

[0189]

[0190] Here, σ c is the central tensile stress (CT, MPa), σ o and σ i are the surface compressive stresses (CS, MPa) of the outer and inner walls, respectively, and C d is the diffusion depth (DOL, μm), t is the thickness of the glass (μm). To compensate for the tensile stress on the inner wall surface, σ i ≥ σ o Since the condition must be satisfied, mathematical expression 2 can be derived by combining mathematical expression 1 and the corresponding condition.

[0191] [Equation 2]

[0192]

[0193] In mathematical expression 2, the left side is σ i / σ o If we organize it into a ratio, we can derive mathematical formula 3, c i Wow c o are σ respectively i Wow σ o Since it is proportional to c, equation 3 is i / c o It can also be defined as a ratio.

[0194] [Equation 3]

[0195]

[0196] Here, c o and c irepresents the surface alkali concentration of the outer and inner walls, respectively. According to mathematical expression 3, the minimum ci / c that can offset the tensile stress on the inner wall when asymmetric ion exchange occurs on the outer and inner walls o and σ i / σ o The ratio can be expressed as a function of DOL and glass thickness.

[0197] Figure 40 shows the minimum σ that can offset the CT according to the thickness of the glass and the change in DOL based on mathematical equation 3. i / σ o This is a figure showing the calculated ratio, and Fig. 41 is based on the results calculated in Fig. 40. o When changes are made, the minimum σ i This is a figure that derives the value of σ. i / σ o The ratio tends to increase as the DOL increases relative to the thickness. For example, based on BS glass with a thickness of 1.2 mm and CS and DOL of 300 MPa and 30 μm, respectively, the minimum σ required for the inner wall i / σ o The ratio is about 1.44%, where σ i is about 4 MPa. As another example, based on AS glass with a thickness of 1.2 mm and CS and DOL of 500 MPa and 60 μm, respectively, the minimum σ required for the inner wall is i / σ o The ratio is approximately 2.86%, where σ i was calculated to be around 14 MPa.

[0198] 2.4. Screw neck vial target spray process internal ion exchange

[0199] In this example, a coating film was formed on the inside of the vial, including the bottom and walls, and then ion exchange was performed to evaluate the coating uniformity and ion exchange characteristics of the glass vials manufactured. At this time, the glass vials used for ion exchange were screw neck (5 ml) and screw neck (10 ml) vials with different shapes. The slurry was added to 100 ml of water solvent at a molar ratio of approximately 28:72, 18:82, and 16:84 based on the KNO3:TiO2, and the slurry was sprayed into the opening of the glass vial at room temperature and 60% humidity under a pressure of 6 bar to form a coating film on the inner surface of the glass vial, and then dried under the same temperature and humidity conditions. At this time, the viscosity of the slurry was not measured, but based on two pieces of information, namely, the tendency for viscosity to increase according to the TiO2 molar ratio as shown in Fig. 2 and the viscosity of 750 mPa·s when the KNO3:TiO2 molar ratio is approximately 44:56, it can be inferred that the viscosity is higher than that value.

[0200] Fig. 42 is a side view photograph of the inside of two types of screw neck vials when applying a metal oxide particle-based alkali salt slurry based on a room temperature spray process, and Fig. 43 is a picture showing a bottom view. Under the vial diameter and spray conditions, a slurry with a composition of approximately 18:82 based on the KNO3:TiO2 molar ratio had an appropriate viscosity, so that the internal coating was uniform. In the case of compositions with lower or higher viscosity compared to the corresponding composition, unevenness of the coating film was caused due to the coating film flowing down and nozzle clogging. In the case of bottom coating, as with the inner wall, a composition with a KNO3:TiO2 molar ratio of approximately 18:82 showed the most uniform coating quality, and in the case of a 10 ml vial, it was confirmed that the deterioration of the coating film quality occurred more significantly as the spray distance increased.

[0201] Figure 44 is a drawing showing photographs of a glass vial having a coating formed on the inside thereof using the above-described method, observed with a polarizer before and after removal of the coating after heat treatment at 450°C for 40 hours. The coating was cleaned by immersing it in purified water at 60°C for 60 minutes in an ultrasonic cleaner with an output of 40 kW, and contamination occurred on the wall after cleaning.

[0202] Figure 45 is a graph showing the results of measuring the alkali concentration distribution in the ion exchange direction at the bottom of a glass vial after the removal of the coating film following internal ion exchange using SEM-EDS, and the concentration measurement locations are indicated. The normalized ion exchange concentration shown here was calculated as the ratio of the ion-exchanged K concentration to the total alkali concentration (Na + K). It was confirmed that the ion exchange at the bottom occurred at an appropriate level in terms of surface concentration and diffusion depth, and that the degree of ion exchange was similar at the center and edge.

[0203] 2.5. Crimp neck vial target spray process internal ion exchange

[0204] In this example, internal ion exchange was performed on crimp neck (5 ml) and (10 ml) glass vials. The internal ion exchange performed on the screw neck vials described above was performed on vials of relatively small diameter, but the slurry composition and injection pressure were changed to accommodate internal application in vials of various specifications.

[0205] In this example, a coating film was formed on the inside of a crimp neck vial, including the bottom and walls, and then ion exchange was performed to evaluate the coating uniformity and ion exchange characteristics of the glass vials manufactured. Four types of slurries were manufactured by adding KNO3:TiO2 to 100 ml of water solvent at molar ratios of approximately 66:34, 57:43, 50:50, and 44:56, and sprayed at room temperature and 60% humidity at pressures of 1, 1.5, and 2 bar. At this time, spraying was performed by installing a spray nozzle in the opening of the glass vial, and after forming a coating film on the inner surface of the glass vial, it was dried under the same temperature and humidity conditions. Here, the viscosity of the slurry prepared by adding KNO3:TiO2 at molar ratios of approximately 66:34, 57:43, 50:50, and 44:56 was confirmed to be 43, 220, 470, and 750 mPa·s, respectively, as shown in the results shown in Fig. 2 above, based on the measurement standard of a spindle speed of 100 rpm of a rotational viscometer.

[0206] Fig. 46 is a picture showing the bottom according to the slurry composition and injection pressure after slurry application to the inside of a crimp neck vial, and Fig. 47 is a picture showing the side view. In the slurry with a KNO3:TiO2 molar ratio of about 66:34, the viscosity of the slurry was low at about 43 mPa·s, which caused cracking and flowing of the coating film. In addition, when the KNO3:TiO2 molar ratio was about 44:56, the viscosity of the slurry was excessively high at about 750 mPa·s, which caused the unevenness of the coating film to be visually confirmed. Therefore, in the ranges of KNO3:TiO2 molar ratios of about 57:43 and 50:50, the viscosity was about 220 and 470 mPa·s, respectively, and the quality of the coating film was relatively uniform, which was determined to be the optimal composition for the application conditions inside the vial.

[0207] Figure 48 is a drawing showing photographs of a glass vial having a coating formed inside the vial by the above-described method, heat-treated at 450°C for 16 hours, and observed with a polarizer before and after removing the coating. The coating was cleaned by immersing it in purified water at 60°C for 60 minutes in an ultrasonic cleaner with an output of 40 kW. As a result of observation with a polarizer, it was confirmed that contamination occurred only under the conditions of composition 4 and injection pressure 1 bar, and that contamination did not occur under other conditions. When combined with the results of Example 2.4 described above, it was confirmed that the frequency of contamination increased as the relative ratio of TiO2 within the coating increased.

[0208] Figure 49 is a graph showing the results of measuring the surface alkali concentration distribution in the direction perpendicular to the ion exchange direction on the side surface of a glass vial after the removal of the coating film following internal ion exchange using SEM-EDS, and is an inserted picture of the side surface of the glass vial where the concentration measurement was performed. At this time, the normalized ion exchange concentration shown was calculated as the ratio of the ion-exchanged K concentration to the total alkali concentration (Na + K). In the case of the normalized surface concentration, it was in the range of 0.3-0.6 over the entire area of ​​the side surface, and it was confirmed that the concentration uniformity was higher when the KNO3:TiO2 molar ratio of the slurry was 50:50 than when it was 44:56.

[0209] Fig. 50 is a graph showing the results of measuring the alkali concentration distribution in the ion-exchange depth direction using SEM-EDS after cutting the bottom of the glass vial manufactured by the above-described method, and is a drawing with the concentration measurement location inserted. At this time, the normalized ion-exchange concentration was calculated as the ratio of the ion-exchanged K concentration to the total alkali concentration (Na + K). Here, Fig. 49 (a) shows the case where the KNO3:TiO2 molar ratio in the slurry is about 57:43, and Fig. 49 (b) shows the case where it is about 50:50. As a result of measuring the alkali concentration distribution in the depth direction at locations 1 (edge), 2 (center), and 3 (edge) of the bottom, the surface concentration uniformity of the bottom was relatively uniform compared to the wall, and the surface concentration was confirmed to be in the range of 0.5-0.75. When the results of Figures 32 and 33 are summarized, when the internal ion exchange technology developed in this example is applied, the ion exchange concentration conditions (C) that do not significantly impair the chemical durability described above i It was confirmed that the ≤ 0.75) can be satisfied.

[0210] 2.6. Paste process dry method internal ion exchange

[0211] In this example, internal ion exchange was performed using a metal oxide slurry containing a viscosity enhancer in a crimp neck (10 ml) glass vial. A paste composition containing a viscosity enhancer was used based on the slurry composition satisfying the optimal viscosity previously described in Example 1.5. In this case, the application method may be either a brush coating method or a drainage coating method.

[0212] Figure 50 is a schematic diagram illustrating the two coating processes described above. For brush coating, a brush with a diameter smaller than the inner diameter of the glass container must be used, and the slurry can be applied to the inner wall surface of the target glass container or by rotating the brush. For drainage coating, the slurry is injected into the glass container via spray or dip coating, and then the remaining waste liquid is removed. The remaining waste liquid can be removed by gravity simply by inverting the glass container, or by additional tools such as a knife or brush.

[0213] Figures 51 to 52 are drawings showing the appearance of glass vials subjected to ion exchange heat treatment by brush and drain coating methods according to the process method and slurry composition. In this experiment, the glass vials were both crimp neck (10 ml) glass vials. The paste was prepared by adding KNO3:TiO2 at a molar ratio of approximately 68:32 to 100 ml of water solvent. The prepared pastes were coated on the outer surface of the glass vials at room temperature and 60% humidity by brush coating or drain coating methods, and then dried in a constant temperature and humidity chamber at 65°C and 20% humidity.

[0214] Fig. 51 is a drawing showing the shape of the coating film after ion exchange heat treatment of a glass vial whose interior was ion exchanged using the above-described method. Here, paste compositions A and B have different types of viscosity enhancers, and a larger number means an increase in the content of the viscosity enhancer. For each slurry composition, the coating was applied under the conditions of a drawing speed of 1 mm / s and 5 mm / s. At this time, the viscosity range of the slurry is approximately 450 mPa·s to 650 mPa·s for the A series, and 650 mPa·s to 1600 mPa·s for the B series. It was confirmed that the internal coating film after ion exchange was uniformly maintained without any uncoated area in all slurry compositions and coating methods. In particular, it was confirmed that no defects such as peeling or cracking of the coating film were observed even in locations with multiple curvatures, such as the wall portion and the connecting portion between the base and the wall portion after heat treatment.

[0215] Figure 52 is a photograph of a surface light source after cleaning the coating film of a glass vial whose interior was ion-exchanged using the above-described method. The coating film was cleaned by immersing it in purified water at 60°C for 60 minutes in an ultrasonic cleaner with an output of 40 kW. Surface light source observation confirmed that the coating film was completely removed under all slurry compositions and coating conditions, resulting in no contamination. In addition, there was no shape distortion or uneven shape change due to internal ion exchange.

[0216] 2.7 Confirmation of internal ion exchange reproducibility in the paste process dry method

[0217] In this example, a total of 24 specimens were manufactured under the same process conditions to confirm the process reproducibility of the internal dry ion exchange described in Example 2.6.

[0218] In this reproducibility verification experiment, both glass vials were crimp neck (10 ml) glass vials, and the slurry was prepared by adding KNO3:TiO2 molar ratio of approximately 68:32 and a viscosity enhancer to 100 ml of water as a solvent. The prepared slurry was coated on the inner surface of the glass vial using a drainage coating method at room temperature and 60% humidity. At this time, the viscosity of the slurry was confirmed to be approximately 650 mPa·s. After forming a coating film on the inner surface of the glass vial using the drainage coating method, the prepared paste was dried in a constant temperature and humidity chamber at a temperature of 65 ℃ and a humidity of 20%. The ion exchange heat treatment was performed at 450 ℃ for 16 hours.

[0219] Figures 53 and 54 are photographs of specimens after drying the coating film of a glass vial whose interior was ion-exchanged by the dry method and after removing the coating film after ion exchange. Here, each specimen was numbered 1-24. Figure 53 shows the shape of the coating film after drying, and it can be visually confirmed that the coating film was uniformly formed on a total of 24 specimens. Figure 54 shows the results of visually inspecting specimens with the coating film removed after ion exchange by placing them on a surface light source. Here, the coating film was cleaned by immersing them in purified water at 60°C for 60 minutes in an ultrasonic cleaner with an output of 40 kW. At this time, it was confirmed that no unevenness or defects occurred in any specimens even in specimens that underwent ion exchange heat treatment for a relatively long period of time.

[0220] 2.8 Paste Process Dry Method Internal Ion Exchange Characteristics Control Case

[0221] In this example, the possibility of controlling the ion exchange characteristic indicators verified for the external ion exchange process in Example 1.7 was applied to the internal ion exchange process to evaluate it.

[0222] Slurries were prepared in four types, with a viscosity enhancer and KNO3:TiO2 molar ratio of about 24:76, about 11:89, about 6:94, and about 3:97 in 100 ml of water solvent. At this time, the viscosity of the slurries was not measured, but the slurries with a viscosity of about 650 mPa·s and the content of the viscosity enhancer were prepared in the same manner. The prepared paste was applied to the glass surface by a drainage coating method at room temperature and 60% humidity, and then dried in a constant temperature and humidity chamber at 65°C and 20% humidity. The ion exchange heat treatment was performed under three conditions: 500°C for 5 hours, 450°C for 6 hours, and 450°C for 16 hours, respectively.

[0223] Figure 55 is a photograph illustrating the appearance of the coating film before and after ion exchange according to each slurry composition and heat treatment condition. According to Figure 55, regardless of the relative KNO3 content, the appearance of the coating film formed inside the glass container using the drainage coating method was uniform for all compositions, and it was confirmed that the coating film was stably maintained without unnecessary flow, peeling, or cracking even after ion exchange.

[0224] The slurry composition utilized in the above-described Figure 55 has been proven to be capable of controlling ion exchange characteristic indices through the case of controlling characteristic indices during external ion exchange in Example 1.7, and based on this, it can be inferred that it is possible to effectively secure chemical durability inside a glass container through uniform ion exchange and intentional control of ion exchange characteristic indices during internal ion exchange.

[0225] 3. Glass vial position-selective ion exchange

[0226] 3.1. Overview of site-selective ion exchange

[0227] Defects in glass vials are mainly caused by contact with other glass vial surfaces during molding, filling, transportation, and handling, and it has been reported that more than 90% of the defects occur in the body, heel, and footprint areas (RA Schaut et al., PDA J. Pharm. Sci. Technol. 71, (2017) 511). As a result of calculating the stress distribution of glass vials according to load through computer simulation, it was confirmed that stress is concentrated in the upper / lower parts and shoulders of the body during the transportation process, and stress is concentrated in the bottom and center of the body when an internal pressure load is applied (https: / www.gerresheimer.com / fileadmin / user_upload / user_upload / landingpages / Lightweight_2022 / Gerresheimer_WP_Lightweight_Glass_Packaging__072022.pdf). Therefore, in order to prevent breakage during the vial process, essential reinforcement is required for the outer walls of the shoulder, bottom, and upper / lower parts of the body. In addition, since breakage occurs in the middle of the body area during the filling process, a method for relieving tensile stress in the above-mentioned areas is required. Figure 56 is a drawing showing a table for explaining the stress concentration area of ​​the vial.

[0228] Figure 57 is a schematic diagram illustrating the vial reinforcement area of ​​existing ion exchange technology. Existing ion exchange technology uniformly reinforces the entire vial area, making additional reinforcement of stress-concentrated areas impossible. In case 1, cases have been previously reported where the pressure characteristics are similar to or even deteriorate compared to unreinforced products.

[0229] Fig. 58 is a diagram illustrating the concept of position-selective ion exchange, and shows several cases of additionally strengthening the stress-concentrated area of ​​the glass vial shown in the table of Fig. 56, and attempts to solve the problems of the existing ion exchange technology described above by utilizing the metal oxide-based dry method of the present invention. For example, in case 3, only the stress-concentrated area is strengthened, and the central part of the body, which is the cause of internal pressure failure, is intentionally not strengthened, so that the internal pressure characteristics can be improved with external application alone. Alternatively, the concept of position-selective ion exchange that strengthens the entire area but provides a gradient in ion exchange characteristics between the stress-concentrated area and other areas to additionally strengthen the stress-concentrated area is also possible. Additionally, as in case 5, it is expected that a glass vial with even improved durability can be manufactured by combining external ion exchange and internal ion exchange by combining the concept of Examples 1 and 2 or Examples 3 and 2.

[0230] 3.2. Case study of location-selective ion exchange stress concentration zone reinforcement

[0231] In this example, a case of introducing the stress concentration zone reinforcement concept, Case 3 of FIG. 58, among the aforementioned location-selective ion exchange concepts, is presented. Here, the glass vials to be reinforced are crimp necks (5 ml) and crimp necks (10 ml), and the slurry was prepared by adding KNO3:TiO2 at a molar ratio of approximately 66:34 to 100 ml of water solvent, and 3M tape was attached to the outer wall of the vial to perform masking before spraying. The masking locations were the central body, neck, and flange areas. The spraying was performed at a distance of 1 m at room temperature and 60% humidity with a pressure of 8 bar using a general gravity spray gun to form a coating film on the surface of the glass vial, and then dried under the same temperature and humidity conditions. In order to form a coating film over the entire area of ​​the glass vial, the vial was rotated 90° each time, and the spraying and drying process was repeated a total of 4 times. After drying was complete, the attached 3M tape was removed. For reference, this embodiment was manufactured using the same process as Example 1, except for the additional masking process introduced in this embodiment.

[0232] Figure 59 is a drawing showing photographs of a specimen formed with a coating using the above-described method before and after ion exchange. When checking the condition of the coating before ion exchange, the distinction between the reinforced and unreinforced areas was clearly distinguished, and the uniformity of the coating could be confirmed with the naked eye. The ion exchange was conducted at 450°C for 16 and 2 hours, respectively. When the specimen was placed upright in an electric furnace and ion exchanged, it was confirmed that no flow or dripping of the coating occurred after ion exchange under all conditions.

[0233] Figure 60 shows the naked eye and polarizing observation photographs of a site-selective ion-exchange specimen after the coating was removed. At this time, no boundary line was observed between the reinforced and unreinforced regions. Typically, a boundary line between the reinforced and unreinforced regions can be seen with the naked eye or through a polarizer due to the difference in surface refractive index during site-selective ion-exchange in alkali aluminosilicate glass compositions. However, in this case, no boundary line was observed at all, and this is believed to be due to the relatively low ion-exchange amount of the borosilicate composition.

[0234] Fig. 61 is a diagram illustrating the CS and DOL measurements of glass vials that were site-selectively ion-exchanged at 450°C for 16 and 2 hours, respectively, using FSM equipment. The results were measured at the lower part of the outer wall body of the glass vial, and each specimen was measured four times in total to calculate the average value. It was confirmed that CS and DOL were measured at similar values ​​to those in Example 1.3, which performed the same ion-exchange process. As shown in Fig. 62, no interference wrinkles were observed in the central part of the outer wall body where the coating film was not formed, confirming that ion exchange did not occur in the unreinforced region. Based on the above, it was proven that the concentration level of ions to be ion-exchanged can be controlled depending on the location in the specimen, and thus the ion-exchange characteristics can be selectively controlled depending on the location. In addition, by introducing the ion-exchange characteristic control case described in Example 1.8 into the site-selective ion-exchange case, it is possible to implement a case where the ion-exchange level can be changed at a specific location.

[0235] 3.3 Case study of improved mechanical durability through location-selective ion exchange

[0236] In this example, we aimed to determine the difference in mechanical durability, particularly pressure strength, according to the change in the application area during full-area or location-selective ion exchange. Here, the glass vial to be strengthened was a crimp neck (10 ml), and the slurry was prepared by adding KNO3:TiO2 at a molar ratio of approximately 66:34 to 100 ml of water solvent. For location-selective application, 3M tape was attached to the outer surface of a specific specimen to mask it. The masked areas were the center of the body, the neck, and the flange. The spray was performed using a general gravity spray gun at a pressure of 8 bar at room temperature and 60% humidity from a distance of 1 m to form a coating film on the surface of the glass vial, which was then dried under the same temperature and humidity conditions. To form a coating film over the entire area of ​​the glass vial, the vial was rotated 90° each time, and the spraying and drying process was repeated four times in total. After drying was complete, the attached 3M tape was removed. In this example, the same process as Example 1 was used for production, except for the additional masking process introduced.

[0237] Figure 63 is a schematic diagram illustrating the location-selective ion exchange regions utilized in this embodiment. Specifically, Case 1 strengthens the entire external region, Case 2 selectively strengthens the stress-concentrated region within the external region, Case 3 strengthens the entire external and internal regions, and Case 4 strengthens the entire external region while intentionally lowering the ion exchange characteristic index.

[0238] Figure 64 is a drawing showing photographs of specimens on which a coating film was formed using the above-described method after drying, for each coating area case. At this time, 8 specimens were produced for each case, and a total of 32 specimens were produced. When checking the condition of the coating film before ion exchange, the distinction between the reinforced and unreinforced areas was clearly distinguished, and the uniformity of the coating film could be confirmed with the naked eye. The ion exchange was performed at 500°C for 5 hours, and when the specimen was placed upright in an electric furnace and ion exchanged, it was confirmed that no flow or dripping of the coating film occurred under all conditions after ion exchange.

[0239] Figure 65 is a graph showing the CS and DOL of glass vials ion-exchanged at 500 ℃ for 5 hours using FSM equipment. Figure 65 (a) is a graph showing the measurement results of Case 1, and Figure 65 (b) is a graph showing the measurement results of Case 4. Each specimen was measured a total of 8 times and the average value was calculated. The CS and DOL of Case 1 were the same values ​​as those of Example 1.3, which performed the same ion-exchange process, and in the case of Case 4, there was a difference in the ion-exchange characteristic indices of about 5 times when compared with Case 1 based on the product of CS and DOL.

[0240] Figure 66 is a graph summarizing the results of ion-exchanged vials and pressure strength measurements for each case. Figure 67 is a table showing the ion-exchange areas and ion-exchange characteristic indices of glass vials subjected to pressure strength measurements for each case. Here, glass vials that did not undergo ion exchange are indicated for comparison. At this time, the maximum measured pressure strength of the equipment used in this pressure test is 6 MPa. Additionally, a drop breakage test was also conducted on specimens that did not break during the pressure test, in which the target glass vials were dropped onto a steel plate from a height of 1.5 m.

[0241] According to Figures 66 and 67, the average pressure strength increased significantly after ion exchange, and was the highest in Case 3, where both the outer and inner walls were reinforced simultaneously. When Cases 1 and 4, where the entire outer wall was reinforced, were compared, it was confirmed that the average pressure strength also increased as the chemical strengthening index increased. The minimum pressure strength was improved when both the outer and inner walls were reinforced simultaneously, and when only the outer wall was reinforced, the minimum pressure strength was confirmed to be similar to that of the non-ion-exchanged specimen regardless of the chemical strengthening index. The maximum pressure strength increased after ion exchange, and some specimens did not break even at the measurement limit of 6 MPa. When only the outer wall was reinforced, the maximum pressure value increased, and when the outer and inner walls were reinforced simultaneously, the proportion of specimens that did not break increased. In addition, a drop failure test was conducted on specimens that did not break after the pressure test, in which the specimens were dropped from a height of 1.5 meters onto a steel plate. As a result, the drop failure rates of Cases 1, 2, and 3 were confirmed to be approximately 25%, 0%, and 14%, respectively, indicating an improved result compared to the 30% failure rate of the non-ion-exchanged specimen.

[0242] The above description of the present invention is for illustrative purposes only, and those skilled in the art will readily appreciate that the present invention can be readily modified into other specific forms without altering the technical spirit or essential characteristics of the present invention. Therefore, the embodiments described above should be understood as illustrative in all respects and not restrictive. For example, each component described as a single entity may be implemented in a distributed manner, and similarly, components described as distributed may be implemented in a combined manner.

[0243] The scope of the present invention is indicated by the claims described below rather than the detailed description above, and all changes or modifications derived from the meaning and scope of the claims and their equivalent concepts should be interpreted as being included in the scope of the present invention.

Claims

As a method for chemical strengthening of glass containers based on an ion exchange process, A step of preparing a slurry by mixing salt and metal oxide particles; A step of applying the slurry to at least one of at least a portion of the outer wall surface and at least a portion of the inner wall surface of the glass container; and Including a step of heat treating a glass container to which the above slurry is applied, A method wherein each of the manufacturing step, the coating step, and the heat treatment step is performed by taking into consideration at least one of the geometrical characteristics of the inner and outer walls of the glass container, the curvature change characteristics by region, and the thermal stability of the coating film in the heat treatment step. In the first paragraph, The above glass container has a container shape including a base, a wall, a shoulder, and a neck, and has an internal hollow portion with an opening formed at the end of the neck portion. A method in which the above-mentioned curvature change characteristics by region are curvature change characteristics at one or more of the connection regions among the connection region between the base and the wall region, the connection region between the wall region and the shoulder region, and the connection region between the shoulder region and the neck region. In the second paragraph, In the manufacturing step, the slurry is manufactured with a viscosity corresponding to each of the inner and outer walls of the glass container, taking into account the different difficulty of applying the slurry between the inner and outer walls due to the shape in which the width of the opening in the glass container is narrower than the width of the inner hollow. A method in which, in the above-mentioned applying step, the method of applying the slurry is selectively applied to the inner and outer walls of the glass container, respectively, taking into account the different difficulties of applying the slurry. In the third paragraph, The coating method corresponding to the outer wall of the above glass container is a spray coating method or a dip coating method, The coating method corresponding to the inner wall of the above glass container is a drainage coating method, a spray coating method, or a brush coating method. A method in which, when spray coating is applied to both the outer and inner walls of the above glass container, the viscosity of the slurry applied to the inner wall is maintained higher than the viscosity of the slurry applied to the outer wall. In the first paragraph, In order to consider the characteristics of the curvature change by the above-mentioned part, the uniformity of the coating film in the above-mentioned applying step, and the thermal stability of the coating film in the above-mentioned heat treatment step, In the above manufacturing step, the slurry is manufactured so that the viscosity of the slurry applied in the applying step is 13 mPa·s or more and 750 mPa·s or less, A method wherein, in the above-mentioned applying step, the slurry is applied by spray coating when the viscosity is 13 mPa·s or more and 750 mPa·s or less. In the first paragraph, In order to consider the characteristics of the curvature change by the above-mentioned part, the uniformity of the coating film in the above-mentioned applying step, and the thermal stability of the coating film in the above-mentioned heat treatment step, In the above manufacturing step, the slurry is manufactured so that the viscosity of the slurry applied in the applying step is 450 mPa·s or more and 1600 mPa·s or less, A method wherein, in the above-mentioned applying step, the slurry is applied by at least one of a dip coating method, a drainage coating method, and a brush coating method when the viscosity is 450 mPa·s or more and about 1600 mPa·s or less. In the first paragraph, A method wherein, in the above manufacturing step, the salt includes at least one of an alkali salt, a silver salt, a gold salt, or a copper salt. In the first paragraph, A method wherein, in the manufacturing step, the slurry further contains a viscosity enhancer. In the first paragraph, A method wherein the temperature of the above-mentioned applying step is room temperature. In the first paragraph, In the above heat treatment step, A method wherein the above heat treatment temperature is 220°C or higher and 550°C or lower. In the first paragraph, A method wherein the above-mentioned applying step and the above-mentioned heat treating step are performed as a dry process. In Article 11, The above heat treatment step is performed in a dynamic temperature change section where the temperature changes over time by utilizing the relatively low heat capacity characteristics of the coating film formed in the dry process compared to the wet process. A method in which the temperature change rate in the above dynamic temperature change section is set to a maximum of 270 ℃ / min or less, taking into account defects in the coating film that may occur due to the geometrical characteristics of the inner and outer walls of the glass container and the curvature change characteristics by region. In paragraph 12, A method wherein the temperature change rate in the above dynamic temperature change section is set to 180 ℃ / min or less. In paragraph 12, In the above heat treatment step, A method wherein the above dynamic temperature change section includes a temperature increase and heat treatment section. In Article 14, The above dynamic temperature change section is, In the temperature increase section, the temperature change rate is in the range of a maximum of 270 ℃ / min or less, preferably a minimum of 180 ℃ / min or less, A method wherein the temperature change rate in the heat treatment section is in the range of a maximum of 110 ℃ / min or less, preferably a minimum of 70 ℃ / min or less. In the first paragraph, A method for simultaneously imparting thermal strengthening and chemical strengthening effects by using a room temperature metal oxide slurry as a coolant to cool the surface of glass heated above the glass transition temperature in the above heat treatment step. In the first paragraph, A method wherein the stress concentration portion includes at least one of the base portion of the glass container, the upper portion of the wall portion, the lower portion of the wall portion, the shoulder portion, the connection portion between the base portion and the wall portion, the connection portion between the wall portion and the shoulder portion, and the connection portion between the shoulder portion and the neck portion. In the first paragraph, In the above manufacturing step and the above applying step, Considering the stress concentration area of ​​the above glass container, in order to selectively apply the coating film to the application area or locally apply one or more of the composition, thickness and weight of the coating film differently, the coating film is not formed in a location other than the stress concentration area, or In the manufacturing step, the slurry is manufactured so that the salt content of the slurry applied to the stress concentration area is higher than that of the location other than the stress concentration area, or By forming the thickness and weight of the coating film applied to the stress concentration area in the above-mentioned application step smaller than that of the non-stress concentration area, The above method is a method that provides an ion exchange characteristic gradient between a stress concentration area and other areas during ion exchange of an outer wall or inner wall. In the first paragraph, The above-mentioned applying step is performed so that ion exchange occurs on the inner wall, taking into account the stress concentration area of ​​the glass container. A method wherein the ion exchange region of the inner wall includes at least the bottom of the glass container. In the first paragraph, When ion exchange is performed on the inner wall of the above glass container, in order to prevent the chemical stability inside the glass container from deteriorating, the concentration of ion exchanged on the surface of the inner wall, c i The maximum value is provided to be less than 0.75, Here, c i A method in which the ratio of the concentration of ion-exchanged ions to the total alkaline ion concentration in the glass is referred to. In the first paragraph, When ion exchange is performed on the inner and outer walls of the glass container, in order to secure chemical stability inside the glass container and at the same time prevent the formation of tensile stress on the inner wall surface, at least one of the composition, thickness and weight of the coating film applied between the inner and outer walls is set to be different, so that in the slurry manufacturing step, the salt content of the slurry applied to the outer wall is manufactured to be higher than that of the inner wall, or in the coating step, the thickness and weight of the coating film applied to the outer wall are formed to be smaller than that of the inner wall. The concentration of ions exchanged on the surface between the inner and outer walls of the glass container and the surface compressive stress ratio satisfy the following equations: [ceremony] Here, c o and c i are the surface alkali concentration of the outer wall and the ion concentration exchanged on the surface of the inner wall, σ, respectively. o and σ i are the surface compressive stresses of the outer and inner walls, respectively, C d where is the diffusion depth and t is the thickness of the glass. A glass container manufactured by the method of any one of claims 1 to 21, The glass container is any one of a chemically strengthened glass container, a color-changing glass container, and an antibacterial glass container. In paragraph 22, The above glass container is a glass container in which no tensile stress exists in at least one of a portion of the outer wall surface and a portion of the inner wall surface.

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