Glass rod, set of glass rods, use of glass rod and method of manufacturing glass rod

Abstract

To provide a glass product suitable for, for example, flash lamps and other products that repeatedly undergo temperature changes, for example a glass rod, wherein the glass product minimizes and / or completely avoids thermal fracturing during the desired lifecycle of the product.SOLUTION: The above problem is solved by a glass rod having a length lrod of 100 to 1600 mm and having a ratio Zrmax / Zravg between the highest local concentration of ZrO2 and the average ZrO2 concentration of less than 8.0, wherein the highest local concentration Zrmax of ZrO2 is less than 5500 ppm.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present disclosure relates to glass rods, glass rod sets, uses of glass rods, and methods for manufacturing glass rods. Glass rods according to this disclosure are suitable for use in transition glass-based products. Methods for manufacturing glass rods according to this disclosure minimize and / or avoid defects in the glass and final glass products that are evident during subsequent use and subsequent manufacturing steps. [Background technology]

[0002] Transition glass is a highly specialized glass composition adapted and designed for use in flash lamps. Flash lamps are used in medical, industrial, and scientific equipment. Glass compositions used for flash lamp manufacture are subject to rapid and extreme temperature changes. Depending on the type and application of the flash lamp, temperatures can reach 700°C or even higher. Flash lamps are typically made from fused silica / quartz or borosilicate tubes, designed as a U-shape with metal electrodes integrated at both ends. During operation, high-voltage power is supplied via conductive supports that also function as mounting or lamp holders. Transition glass serves to connect the metal conductive supports of the metal electrodes to the flash lamp tube wall, given the large temperature changes during use, especially considering the difference in thermal expansion coefficients between the metal and the glass forming the tube. When flash lamps are used constantly, they undergo hundreds of lighting and cooling cycles, leading to glass degradation, which can manifest as a white layer on the glass. One particularly notable problem that has been repeatedly observed is the thermal breakdown of the glass in flash lamps.

[0003] While transition glasses and products based thereon are known in the art, there is still room for improvement. It would be particularly useful to have glass rods that are subject to reduced physical tension during use, as these tensions could lead to mechanical failure. Summary of the Invention [Problem to be solved by the invention]

[0004] Thus, there remains a need to provide glass products, e.g., glass rods, suitable for, for example, flash lamps and other products that undergo repeated temperature changes, which minimize and / or entirely avoid thermal breakdown during the desired life cycle of the product. Additionally, there remains a related need to provide methods for manufacturing such glass products. [Means for solving the problem]

[0005] Summary of this Disclosure The claimed subject matter meets the above needs.

[0006] In one embodiment, the disclosure provides a method for detecting a cellular signal having a length l rod 100 to 1600 mm, and The ratio of the highest local ZrO2 concentration to the average ZrO2 concentration, Zr max / Zr avg The highest local concentration of ZrO2 is less than 8.0. max The present invention provides a glass rod having a SiO 2 content of less than 5500 ppm.

[0007] In a second aspect, the disclosure provides a set of glass rods comprising at least 40 glass rods according to the first aspect.

[0008] In a third aspect, the disclosure provides a method for manufacturing a glass rod, comprising: providing a reactor (1) comprising a lower discharge opening (2) and one or more reactor walls enclosing a reactor volume; and A step of heating glass raw materials in the reactor to obtain a glass melt (3), wherein the glass melt (3) has a glass composition having a T4 temperature of 1400°C or more, where T4 is the glass melt composition having a viscosity of 10 4 the temperature has a viscosity of 1000 s, and The glass melt (3) is heated to a temperature of 1000°C. 2.5 at least partially heating to a temperature T2.5, defined as the temperature at which the polymer has a viscosity of 100 MPa (100 psi) and holding this temperature for a holding time of at least 10 hours; withdrawing the glass melt (3) from the reactor (1), and cooling and / or shaping said glass melt (3) to obtain one or more glass rods (5) according to the first aspect. The method includes:

[0009] In a fourth aspect, the disclosure provides a method for manufacturing a glass rod, comprising: providing a reactor (1) comprising a lower discharge opening (2), and A step of heating glass raw materials in the reactor to obtain a glass melt (3), wherein the glass melt (3) has a glass composition having a T4 temperature of 1400°C or more, where T4 is the glass melt composition having a viscosity of 10 4 the temperature has a viscosity of 1000 s, and The glass melt (3) is heated to a temperature of 1000°C. 2.5 at least partially heating to a temperature T2.5, which is defined as the temperature at which the viscosity of the material has a viscosity of 100 MPa; and withdrawing the glass melt (3) from the reactor (1) at a withdrawal temperature and a glass melt withdrawal rate; and cooling and / or shaping the glass melt (3) to obtain a glass rod (5); Including, only up to 90% by volume, preferably up to 70% by volume, and most preferably up to 50% by volume of the initial glass melt is used to form the glass melt into a glass rod; and / or the lower discharge opening is located at a distance of at least 10 cm from the reactor wall, and / or the glass melt is not stirred during the holding time, and / or the glass melt is not stirred during drawing, and / or the reactor comprises a top heater, preferably a gas burner, located above the melt surface; The present invention relates to the method.

[0010] In a fifth aspect, the disclosure provides a method for manufacturing a glass rod, comprising: providing a reactor (1) comprising a lower discharge opening (2), and A step of heating glass raw materials in the reactor to obtain a glass melt (3), wherein the glass melt (3) has a glass composition having a T4 temperature of 1400°C or more, where T4 is the glass melt composition having a viscosity of 10 4 the temperature has a viscosity of 1000 s, and The glass melt (3) is heated to a temperature of 1000°C. 2.5 at least partially heating to a temperature T2.5, which is defined as the temperature at which the viscosity of the material has a viscosity of 100 MPa; and withdrawing the glass melt (3) from the reactor (1) at a withdrawal temperature and a glass melt withdrawal rate; and cooling and / or shaping the glass melt (3) to obtain a glass rod (5); Including, interrupting the withdrawal of the glass melt (3) from the reactor (1) before 90% by volume, preferably 70% by volume, and most preferably 50% by volume of the initial glass melt volume has been withdrawn, and / or heating the frit using an upper heater, preferably a gas burner, located above the melting surface, and / or heating the glass melt using an upper heater, preferably a gas burner, located above the melting surface; and / or the withdrawal of the glass melt (3) from the reactor mainly comprises, in particular only, that portion of the glass melt (3) that is at a distance of at least 5 cm from the wall of the reactor (1), The present invention relates to the method.

[0011] Transition glasses have very high glass characteristic temperatures, such as T4 temperatures of 1400°C or higher, where T4 is the temperature at which the glass melt composition reaches 10 4 The temperature at which the glass has a viscosity of 0.05 dPa·s is required for their production. A reactor made of a high-temperature resistant material is required. Various high-temperature resistant materials, such as those based on mullite or andalusite, are known in the art. However, these materials are not suitable for the production of transition glasses due to their very high glass characteristic temperatures. Therefore, high-temperature resistant materials that are mechanically stable even at very high temperatures are used. These high-temperature resistant materials typically include zirconium oxide and zirconium silicate. The inventors have demonstrated that zirconium-based reactor materials are almost unavoidable in the design of reactors for producing transition glasses, and that the incorporation and subsequent contamination of the resulting glass product by zirconium has been identified as a major drawback in the resulting glass, for example, a significant problem that leads to physical tensions in the glass that lead to mechanical fracture in the final product, especially during rapid temperature changes.

[0012] The method for producing glass rods according to the present disclosure solves the above-mentioned problems by minimizing or even avoiding the intrusion of zirconium compounds and / or zirconium ions into the transition glass melt / transition glass and the resulting products thereof. For example, after preparing and homogenizing the synthesized glass, the intrusion of zirconium in the form of zirconium compounds and / or zirconium ions into the glass melt can be reduced by ensuring that essentially no mixing by mechanical agitation (e.g., stirring) of the glass melt is performed after the step of at least partially heating the glass melt to a temperature T2.5 and / or during the step of withdrawing the glass melt from the reactor. In this regard, it should be understood that mechanical agitation is different from thermal convection of the glass melt (agitation due to thermal gradients within the glass melt) and natural flow of the glass melt (agitation due to turbulence during withdrawal of the glass melt from the reactor). Reducing, and especially avoiding, mechanical agitation minimizes and / or reduces the incorporation of zirconium from the reactor walls into the glass melt.

[0013] Without wishing to be bound by theory, it has been found that when stirring is kept to a minimum or avoided, the temperature profile across the length and width dimensions (both horizontal) of the reactor drops toward the reactor wall. The lower the temperature of the glass melt at the interface with the reactor wall, the less zirconium will be dissolved from the wall and introduced into the glass melt. Alternatively or additionally, when withdrawing the glass melt from the reactor, it may be advantageous to withdraw only a portion of the glass melt that is at least 5 cm away from the reactor wall to minimize the potential entrapment of zirconium emanating from the reactor wall. Simulations have demonstrated that adjacent glass melt layers develop from the reactor wall toward the center of the reactor, with the adjacent glass melt layers having varying physical and chemical properties, particularly with respect to their ZrO2 content.

[0014] Depending on the glass composition, the tendency of the melt to dissolve ZrO from the reactor walls can vary. For example, aggressive glass melts, e.g., glass melts containing sodium compounds, e.g., having an amount of sodium compounds of at least 7% by weight, can dissolve substantial portions of the reactor walls even at relatively low temperatures. For highly aggressive glass compositions, it may be necessary to take more than one of the above measures, such as a lower discharge opening location, an upper burner, no stirring, not using the entire volume of the glass melt, etc.

[0015] The inventors calculated the ratio of the highest local concentration of ZrO2 to the average ZrO2 concentration, Zr max / Zr avg We have found that keeping Zr within a certain threshold overcomes the drawbacks of the prior art. Without wishing to be bound by theory, we believe that a large Zr max and Zr max / Zr avg is Zr max It is hypothesized that this can cause localized irregularities at the locations of the cracks, which can lead to stresses within the glass, which can ultimately lead to mechanical failure under the influence of rapid temperature changes. Products based on transition glasses according to this disclosure have demonstrated less cracking and mechanical failure after repeated and prolonged use under extreme and varying temperature conditions. [Brief explanation of the drawings]

[0016] [Figure 1] Figure 1 is a cross-sectional photograph of a glass rod showing an excessive Zrmax concentration. [Figure 2] FIG. 2 is a cross-sectional photograph of a glass rod according to this disclosure. [Figure 3] FIG. 3 is a cross-sectional view of a batch reactor that can be used in the method of this disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0017] Detailed Description Zr maxis defined as the highest local concentration of ZrO2 within the resulting glass rod. According to the present invention, the highest local concentration of ZrO2 is determined in one or more cross sections of the glass rod, for example, by LA-ICP-MS. LA-ICP-MS stands for laser ablation inductively coupled plasma mass spectrometry, which is an analytical technique used to determine the elemental composition of a solid sample. For example, according to this disclosure, Zr max is determined by measuring the ZrO2 concentration in at least 3, at least 5, at least 8, or at least 10 equidistantly distributed cross sections along the length of the glass rod. LA-ICP-MS combines two techniques: laser ablation, which uses a high-power laser to remove (ablate) material from the sample surface, and inductively coupled plasma mass spectrometry, which ionizes the material and then uses mass spectrometry to detect and quantify the ions based on their mass-to-charge ratio. This method is widely used in geology, materials science, and trace element forensic analysis because it is capable of sampling a wide range of materials accurately and with minimal disruption. A more detailed description of the method is provided below.

[0018] The location of the highest local concentration of ZrO2 can be identified by chromatic confocal thickness measurements, which are known to those skilled in the art. Generally, if the optical properties, refractive index, and Abbe number of the sample are known and homogeneous over the measurement area, the thickness (z value) can be calculated from the difference between two distance measurements. Assuming that the absolute thickness is constant, the identified z value is indicative of the wavefront deformation and is an indication of the different densities within the glass rod.

[0019] Alternatively, the central portion of the glass rod is scanned by multiple LA-ICP-MS measurements to locate the highest local concentration of ZrO2.

[0020] In this disclosure, Zr maxis less than 5500 ppm, preferably less than 4000 ppm, more preferably less than 3000 ppm, even more preferably less than 2000 ppm, and most preferably less than 1000 ppm. In this disclosure, unless expressly indicated otherwise, the unit of "ppm" relates to mass to mass (m / m). Optionally, Zr max can be at least 500 ppm, preferably at least 600 ppm, and even more preferably at least 700 ppm. According to a preferred embodiment of the present disclosure, Zr max can range from 500 ppm to 5500 ppm, preferably from 600 ppm to 4000 ppm, and most preferably from 700 ppm to 3000 ppm.

[0021] Zr avg is defined as the average ZrO2 concentration in the glass rod. avg is identified by LA-ICP-MS. Alternatively, Zr avg can be identified by X-ray fluorescence analysis (XRF).

[0022] Quantitative analysis using X-ray fluorescence (XRF) works by measuring the fluorescent (or secondary) X-rays emitted by a material when excited by high-energy X-rays or gamma rays. This technique is based on the principle that individual atoms emit X-ray photons of characteristic energy or wavelength when excited by an external energy source. By measuring the intensity and energy of these emitted X-rays, the composition of the material can be determined. In this disclosure, wavelength-dispersive XRF (WDXRF) is used. This method uses a crystal to diffract X-rays at various angles depending on their wavelength. The intensity of the X-rays emitted at each energy (or wavelength) is proportional to the concentration of the corresponding element in the sample. By calibrating the XRF instrument with standards of known composition, the Zr concentration in a sample can be quantified. XRF is performed on polished glass rod samples.

[0023] In an embodiment of the present disclosure, Zr avgis less than 4000 ppm, preferably less than 3500 ppm, more preferably less than 3000 ppm, even more preferably less than 2600 ppm, even more preferably less than 1500 ppm, even more preferably less than 1000 ppm, and most preferably less than 700 ppm. avg can be at least 200 ppm, preferably at least 300 ppm, more preferably at least 400 ppm, and even more preferably at least 500 ppm. According to a preferred embodiment of the present disclosure, Zr avg can range from 200 ppm to <4000 ppm, preferably from 300 ppm to <3500 ppm, more preferably from 400 ppm to <2600 ppm, and most preferably from 500 ppm to <1000 ppm.

[0024] "Highest local concentration of ZrO2", "average ZrO2 concentration" and "ZrO2 concentration" in the sense of the present invention are Zr 4+ The concentration of Zr ions is normalized to the amount of the corresponding oxide. 4+ The ions may be present in the form of various compounds, such as zirconium dioxide or zirconium silicate.

[0025] In certain embodiments, Zr max / Zr avg is less than 8.0, preferably less than 7.0, more preferably less than 5.0, and most preferably less than 3.0. Using the methods of this disclosure, this ratio can be kept within desired limits. As discussed in more detail elsewhere in this application, the techniques of this disclosure avoid excessive ZrO2 concentrations in the glass rod. In certain embodiments, Zr max / Zr avg is >1.0, preferably at least 1.1, more preferably at least 1.5, and most preferably at least 2.0. According to a preferred embodiment of the present invention, Zr max / Zr avg can range from >1.0 to 8.0, preferably from 1.5 to 7.0, and most preferably from 2.0 to 5.0.

[0026] According to a preferred embodiment of the present disclosure, the glass rod has an average ZrO2 concentration of Zr avg At least 200 ppm, preferably 300 ppm to 3000 ppm, and / or a maximum local concentration of ZrO2 max less than 5500 ppm, preferably less than 2000 ppm, even more preferably less than 1000 ppm, and / or Zr max / Zr avg It has a % RI of less than 8.0, preferably less than 7.0, more preferably less than 5.0, and most preferably less than 3.0.

[0027] According to another preferred embodiment of the present disclosure, the glass rod has an average ZrO2 concentration of Zr avg At least 200 ppm, preferably 300 ppm to 3000 ppm, and the highest local concentration of ZrO2 is Zr max less than 5500 ppm, preferably less than 2000 ppm, even more preferably less than 1000 ppm, and Zr max / Zr avg It has a % RI of less than 8.0, preferably less than 7.0, more preferably less than 5.0, and most preferably less than 3.0.

[0028] The glass rod of this disclosure has a central portion and end portions, the central portion being defined as the portion of the rod located at a distance less than 1 / 2 r from the center of mass of the cross section of the rod, where r is the radius of the cross section, and the end portions being defined as the portion of the glass rod located at a distance of at least 1 / 2 r from the center of mass of the cross section of the rod. If the cross section of the rod is not circular, r is the radius of a circle having the same area as the surface area of ​​the cross section under consideration. In an embodiment, the ZrO2 concentration in the central portion of the glass rod is greater than the ZrO2 concentration in the end portions of the glass rod. For example, Zr max This distribution of ZrO2 concentration in at least some glass rods of this disclosure is a result of the method of manufacturing the glass rods in a crucible containing ZrO2. It has been found that the highest concentration of ZrO2 can occur in the center of the glass rod due to the glass melt being withdrawn from the crucible through the discharge opening.

[0029] Generally, the glass rods of this disclosure may contain very small amounts of other impurities, such as iridium, tungsten, and / or molybdenum, which may enter the melt from electrodes or other components of the crucible or furnace. To ensure that the glass rod exhibits the desired properties, including transmittance, impurities should be kept to a minimum. In some embodiments of this disclosure, molybdenum and / or tungsten contamination can be avoided by not relying on molybdenum and / or tungsten and / or iridium electrodes for heating. Instead, an upper heater can be used to heat the melt from above. In embodiments, the concentration of each of molybdenum and / or tungsten and / or iridium in the glass of the glass rod is less than 100 ppm, preferably less than 50 ppm, more preferably less than 30 ppm, and most preferably less than 10 ppm. In embodiments, the concentration of molybdenum in the glass of the glass rod is less than 100 ppm, preferably less than 50 ppm, more preferably less than 30 ppm, and most preferably less than 10 ppm. In an embodiment, the concentration of tungsten in the glass of the glass rod is less than 100 ppm, preferably less than 50 ppm, even more preferably less than 30 ppm, and most preferably less than 10 ppm. In an embodiment, the concentration of iridium in the glass of the glass rod is less than 100 ppm, preferably less than 30 ppm, even more preferably less than 10 ppm, and most preferably less than 5 ppm.

[0030] High transmittance is achieved by maintaining low levels of impurities and defects. In embodiments, the transmittance of the glass of the glass rod of this disclosure is at least 90%, preferably at least 92%, more preferably at least 95%, and most preferably at least 97%, measured at at least one wavelength in the range of 350-450 nm at a nominal thickness of 10 mm. Optionally, the transmittance of the glass of the glass rod of this disclosure is at least 90%, preferably at least 92%, more preferably at least 95%, and most preferably at least 97%, over the entire wavelength range of 350-450 nm at a nominal thickness of 10 mm.

[0031] In an embodiment, this disclosure provides a method for manufacturing a hologram having a length l of 100 to 1600 mm, preferably 200 to 1400 mm, more preferably 300 to 1300 mm, and most preferably 800 to 1100 mm. rod The present disclosure relates to a glass rod having a length of at least 100 mm, preferably at least 200 mm, more preferably at least 300 mm, and most preferably at least 800 mm. The length of the glass rod can be up to 1600 mm, preferably up to 1400 mm, more preferably up to 1300 mm, and most preferably up to 1300 mm. These lengths have been found to be suitable for economical manufacturing. Furthermore, the method of this disclosure allows for maintaining the desired uniformity of properties within these lengths. In the sense of this disclosure, the length of the rod is the distance between the two ends of the glass rod.

[0032] In an embodiment, this disclosure relates to a glass rod having a thickness of 2.0 to 5.0 mm, preferably 2.2 to 4.5 mm, more preferably 2.5 to 4.0 mm, and most preferably 2.8 to 3.8 mm. Optionally, the glass rod of this disclosure may have a thickness of at least 2.0 mm, preferably at least 2.2 mm, more preferably at least 2.5 mm, and most preferably at least 2.8 mm. For example, the thickness of the glass rod can be up to 5.0 mm, preferably up to 4.5 mm, more preferably up to 4.0 mm, and most preferably up to 3.8 mm. These thicknesses have been found to be suitable for economical manufacturing. Furthermore, the method of this disclosure allows for maintaining the desired uniformity of properties within these thicknesses. In the sense of this disclosure, the thickness of a glass rod is 2 × r, where r is the radius of the glass rod. If the glass rod is elliptical, the thickness of the glass rod is the diameter of its major axis.

[0033] As discussed above, the products and methods of this disclosure provide a highly homogeneous distribution of composition and therefore properties. In embodiments, the glass rod has a mean linear thermal expansion coefficient (hereinafter H ) in the temperature range of 30 to 300°C. CTE ) exhibits a homogeneity of less than 0.08 ppm / K. This means that the difference between the maximum and minimum measurable mean linear thermal expansion coefficients in the glass rod is less than the indicated threshold. Maintaining a low variation in the thermal expansion coefficient in the glass rod helps to achieve good resistance of the glass rod to repeated temperature changes. Measurement of the mean linear thermal expansion coefficient of glass, also known as the mean linear thermal expansion coefficient, is a routine measurement and is known to those skilled in the art. It is measured in the temperature range 20-300°C and is specified in accordance with ISO 7991:1987. Optionally, H CTE can be less than 0.07 ppm / K, preferably less than 0.06 ppm / K. CTE is 0.001 to 0.08 ppm / K, preferably 0.01 to 0.07 ppm / K, and most preferably 0.02 to 0.06 ppm / K.

[0034] According to one embodiment, the present disclosure provides a method for manufacturing a semiconductor device having a length lrod and / or the thickness of the glass rod is in the range of 2.0 mm to 5.0 mm, and / or the uniformity of the average linear thermal expansion coefficient in the temperature range of 30 to 300°C is less than 0.08 ppm / K.

[0035] According to another embodiment, the present disclosure provides a method for manufacturing a semiconductor device having a length l rod The glass rod has a length of 800 to 1100 mm, a thickness of 2.0 mm to 5.0 mm, and a uniformity of the average linear thermal expansion coefficient in the temperature range of 30 to 300°C of less than 0.08 ppm / K.

[0036] This disclosure also relates to a set of glass rods of this disclosure. The properties of the glass rods disclosed herein can be reliably obtained, which means for a significant number of rods. Thus, the glass rods may have lengths l of 100 to 1600 mm. rod and the ratio of the highest local concentration of ZrO2 to the average ZrO2 concentration is Zr max / Zr avg The highest local concentration of ZrO2 is less than 8.0. max A set of glass rods is available with a SiO2 content of less than 5500 ppm.

[0037] According to preferred embodiments of the present disclosure, all of the glass rods in the set exhibit one or more or all of the preferred features discussed in more detail in this disclosure. In embodiments, this disclosure provides a set of glass rods. The set of glass rods may be packaged, sold, shipped, and / or used as a bundle. Optionally, the set of glass rods includes at least 40, preferably at least 60, more preferably at least 80, and most preferably at least 100 glass rods of this disclosure. In embodiments, the set of glass rods includes up to 2000, preferably up to 1000, even more preferably up to 500, and most preferably up to 200 glass rods of this disclosure. For example, the set may include 40 to 2000, preferably 60 to 1000, more preferably 80 to 500, and most preferably 100 to 200 glass rods of this disclosure.

[0038] In certain embodiments, the glass rods of this disclosure are used to bond a metal article to a glass member. For example, the average coefficient of thermal expansion of the glass rod can be between the average coefficient of thermal expansion of the metal article and the average coefficient of thermal expansion of the glass member.

[0039] In one embodiment, the glass rod has one or more of the following properties: fewer than 10, fewer than 5, or fewer than 2 bubbles, each of which has a length of at least 0.5 mm measured as the longest linear distance along the bubble; and / or The bubble length, measured as the longest linear distance along the bubble, is less than 70 mm, less than 50 mm, or less than 10 mm; and / or no bubble spread of more than 100 mm, where bubble spread is defined as the occurrence of a series of bubbles aligned one after the other along the length of the glass rod, the distance between any two adjacent bubbles being less than the length of the longest bubble in the series; It is characterized by:

[0040] Individual bubbles can be observed with the naked eye, for example, using a light table, and can be captured by photography. Individual bubbles can have an approximately spherical shape, but can also appear as elongated, e.g., elliptical, bubbles, also called airlines, whose length is measured along the long axis. Elongated bubbles may not have a well-defined geometric shape and therefore may be irregular in shape. A bubble is counted if its length, measured as the longest linear distance within the bubble, is at least 0.5 mm. If more than one bubble is observed, they may appear as a spread.

[0041] In one embodiment, the glass rod has a bubble count of less than 10, preferably less than 5, more preferably less than 2, wherein the bubble length, measured as the longest linear distance in the bubble, is at least 0.5 mm. According to another preferred embodiment, the glass rod is bubble-free, wherein the bubble length, measured as the longest linear distance in the bubble, is at least 0.5 mm.

[0042] In one embodiment, the glass rod, optionally obtained by the method, has a coefficient of thermal expansion of 0.8 ppm / K to 4.5 ppm / K over the temperature range of 20° C. to 300° C. In one embodiment, the glass rod has a coefficient of thermal expansion of at least 0.95 ppm / K, at least 1.00 ppm / K, at least 1.05 ppm / K, at least 1.10 ppm / K, at least 1.20 ppm / K, or at least 1.50 ppm / K. In one embodiment, the glass rod has a coefficient of thermal expansion of 3.20 ppm / K or less, 3.00 ppm / K or less, 2.70 ppm / K or less, 2.20 ppm / K or less, or 2.00 ppm / K or less. In one embodiment, the glass rod has a thermal expansion coefficient of 0.95 ppm / K to 3.20 ppm / K, 1.00 ppm / K to 3.00 ppm / K, 1.05 ppm / K to 2.70 ppm / K, 1.10 ppm / K to 2.20 ppm / K, 1.20 ppm / K to 2.20 ppm / K, or 1.50 ppm / K to 2.00 ppm / K.

[0043] The water content can be determined by IR spectroscopy based on the OH stretching vibration at about 2700 nm, for example using a commercially available Nicolet FTIR spectrometer. Absorption can be first measured in the wavelength range of 2500-6500 nm, and then the absorption maximum can be determined at about 2700 nm (or in that range). The absorption coefficient α is determined by the sample thickness d and the internal transmittance T i and reflectance P, calculated using the following formula: α=1 / d·lg(1 / T i )[cm -1 ], In the above formula, T i =T / P, where T is the transmittance. c=α / ε where ε is the extinction coefficient. For a water content in the range of 25 to 80 mmol / l, ε = 110 l mol -1 cm -1 (H. Frank and H. Scholze, "Glastechnische Berichte", Vol. 36, No. 9, p. 350).

[0044] In one embodiment, the glass article has a relative deviation in water content of at most 10%, at most 8%, at most 6%, at most 4%, or at most 2% and / or at most 5 mmol / l, at most 4 mmol / l, at most 3 mmol / l, at most 2 mmol / l, or at most 1 mmol / l. In one embodiment, the glass article has a relative deviation in water content of at least 0.2%, at least 0.4%, at least 0.6%, at least 0.8%, or at least 1.0%, and / or at least 0.1 mmol / l, at least 0.2 mmol / l, at least 0.3 mmol / l, at least 0.4 mmol / l, or at least 0.5 mmol / l.

[0045] In one embodiment, the present invention relates to a set of glass articles, each having a moisture content of at least 35 mmol / l, at least 40 mmol / l, at least 45 mmol / l, at least 50 mmol / l, or at least 55 mmol / l, and / or a moisture content of 250 mmol / l or less, 200 mmol / l or less, 150 mmol / l or less, 125 mmol / l or less, or 100 mmol / l or less. Accordingly, in one embodiment, there is provided a set of glass articles, each having a moisture content of 35 to 250 mmol / l, 40 to 200 mmol / l, 45 to 150 mmol / l, 50 to 125 mmol / l, or 55 to 100 mmol / l.

[0046] Advantageously, a water content of at least 35 mmol / l or at least 55 mmol / l serves to reduce the occurrence of glass breakage and / or glass defects upon repeated and multiple (re)heating and / or glass production.

[0047] method The method of this disclosure comprises: Providing a reactor (1) comprising a lower discharge opening (2) and one or more reactor walls enclosing a reactor volume; A step of heating glass raw materials in the reactor to obtain a glass melt (3), wherein the glass melt (3) has a glass composition having a T4 temperature of 1400°C or more, where T4 is the glass melt composition having a viscosity of 10 4 the temperature is dPa s, The glass melt (3) is heated to a temperature of 1000°C. 2.5 at least partially heating to a temperature T2.5, defined as the temperature at which the melting point has a melting point of at least 10 dPa·s, and optionally holding this temperature for a holding time of at least 10 hours; withdrawing the glass melt (3) from the reactor (1), and cooling and / or shaping said glass melt (3) to obtain one or more glass rods (5); Includes.

[0048] The method of the present disclosure can be carried out batchwise, which means that the steps of heating the glass frit, heating the glass melt, drawing the glass melt, and obtaining a glass rod can be carried out repeatedly.

[0049] In embodiments, only up to 90 vol%, preferably up to 70 vol%, more preferably up to 60 vol%, and most preferably up to 50 vol% of the volume of the glass melt is used to form the glass melt into a glass rod. Generally, those skilled in the art with the benefit of this disclosure can determine the amount of glass melt that can be used to produce the superior glass rods of this disclosure depending on the size of the reactor, the corrosiveness of the glass melt, the melting temperature, etc. However, for economic reasons, it is useful to use at least 25 vol%, preferably at least 30 vol%, and most preferably at least 35 vol% of the initial glass melt for the superior glass rods of this disclosure. This does not necessarily mean that the remaining glass melt is discarded. The remaining melt can still be used to produce glass rods for different purposes that do not require the superior quality discussed herein. Furthermore, optionally, the method can include a step of interrupting the withdrawal of the glass melt from the reactor before 90 vol%, preferably 70 vol%, more preferably 60 vol%, and most preferably 50 vol% of the volume of the initial glass melt has been withdrawn. The initial volume of the glass melt is the volume of the melt after the raw materials have completely melted, i.e., in the liquid state.

[0050] According to one embodiment, in order to reduce the amount of wall material, and therefore zirconium compounds such as zirconium dioxide and / or zirconium silicate, penetrating the melt, it is desirable to position the lower discharge opening at a distance of at least 10 cm, preferably at least 15 cm, more preferably at least 20 cm, and most preferably at least 25 cm, from the reactor wall. Typically, it is useful to position the lower discharge opening approximately in the center of the reactor bottom. This distance can be the shortest distance between the reactor wall and the lower discharge opening. The lower discharge opening may include a nozzle, often referred to as a "die." The die may be selected to be Zr-free. In an embodiment, the withdrawal of the glass melt from the reactor primarily includes, and in particular only includes, a portion of the glass melt that is at least 5 cm, preferably at least 10 cm, and most preferably at least 15 cm from the reactor wall. Because the reactor wall is the source of ZrO2 concentration in the glass melt, withdrawing the glass melt primarily from a portion of the melt that is distant from the wall helps achieve a desired low level of contamination. In general, the portion of melt withdrawn from the glass melt can be influenced by the heating means, the location of the lower discharge opening, the stirring, and the viscosity of the melt.

[0051] In a preferred embodiment, the glass melt is not mechanically agitated, e.g., by stirring, during the holding time and / or during withdrawal. Glass manufacturers often stir glass melts for homogenization purposes. The inventors unexpectedly discovered that stirring increases the amount of zirconium compounds, e.g., zirconium dioxide and / or zirconium silicate, that penetrate the melt from the reactor walls. Therefore, reducing or avoiding mechanical agitation, e.g., stirring, leads to lower levels of ZrO2 concentration in the glass melt according to this disclosure. Agitation during the initial melting stage can also be avoided. However, some agitation during the initial melting (before the glass frits are completely melted) can be tolerated to aid in the initiation of melting.

[0052] For example, after preparing and homogenizing the synthesized glass, the intrusion of zirconium in the form of zirconium compounds and / or zirconium ions into the glass melt can be reduced by ensuring that essentially no mixing by mechanical agitation (e.g., stirring) of the glass melt is performed after the step of at least partially heating the glass melt to a temperature T2.5 and / or during the step of withdrawing the glass melt from the reactor.

[0053] As discussed above, the method of the present disclosure includes at least partially heating the glass melt to a temperature T2.5 and holding this temperature for a holding time of at least 10 hours. Optionally, this temperature can be held for longer, e.g., at least 15 hours, at least 20 hours, at least 25 hours, or at least 30 hours. In embodiments, the holding time is up to 200 hours, e.g., up to 150 hours, up to 100 hours, or up to 72 hours. For example, the holding time can range from 10 hours to 200 hours, preferably from 15 hours to 150 hours, more preferably from 20 hours to 100 hours, and most preferably from 25 hours to 72 hours. Applying a significantly longer holding time allows the melt to slowly homogenize without stirring.

[0054] To reduce the amount of zirconium dioxide and / or zirconium silicate in the glass melt, an upper heater, i.e., a heater disposed above the melting surface of the glass melt, can be used. For example, the upper heater can be a gas burner, e.g., burning natural gas, other fossil fuels, and / or hydrogen. Without being bound by theory, the inventors believe that the use of an upper heater helps achieve a temperature profile with lower temperatures near the walls and higher temperatures near the center of the reactor volume. A lower temperature near the walls makes the glass melt in that area more viscous, flows more slowly, and therefore picks up less wall material. Therefore, according to a preferred embodiment, the method includes heating the glass frit using an upper heater, preferably a gas burner, disposed above the melting surface. Optionally, the method can include heating the glass melt using an upper heater, preferably a gas burner, disposed above the melting surface.

[0055] The reactor can comprise a refractory material, the refractory material comprising zirconium oxide and / or zirconium silicate, and optionally the melting furnace is essentially free of molybdenum, tungsten, and / or iridium. In an embodiment, the contact surface of the reactor that contacts the glass melt comprises at least 30 wt.%, at least 50 wt.%, or at least 70 wt.% zirconium-containing material. The zirconium-containing material can be selected from zirconia and zirconium silicate. Optionally, the reactor comprises 30 wt.% or more of the contact material in the form of a cast zirconia material containing more than 70 wt.% ZrO, and / or the contact surface of the reactor that contacts the glass melt comprises a sintered material having more than 80 wt.%, more than 90 wt.%, or more than 95 wt.% zirconium silicate.

[0056] In an embodiment, the reactor has an internal length of at least 200 mm, preferably at least 400 mm, and most preferably at least 600 mm, the internal length being related to the longest dimension measured horizontally within the reactor. The reactor can have an internal width of at least 200 mm, preferably at least 300 mm, and most preferably at least 400 mm, the internal width being related to the longest dimension measured horizontally within the reactor and perpendicular to a line defining the internal length. The reactor can have an internal height of at least 100 mm, preferably at least 120 mm, and most preferably at least 150 mm, the internal height being related to the vertical distance between the deepest point of the reactor and the highest point of the reactor measured vertically.

[0057] In the process, the reactor may contain a frit weight of at least 30 kg, at least 40 kg, at least 55 kg, or at least 70 kg, in particular before heating. Additionally or alternatively in the process, the reactor may contain an initial glass melt weight of at least 30 kg, preferably at least 40 kg, more preferably at least 55 kg, and most preferably at least 70 kg, wherein the initial glass melt weight is defined as the weight of the glass melt after complete melting of the frit but before the melt is drawn off.

[0058] Before withdrawing the glass melt from the reactor, the glass melt can be cooled to a lower temperature. For example, the glass melt can be cooled to a temperature T3 or to a temperature T4. In a preferred embodiment, cooling of the glass melt is accomplished by reducing or avoiding further heating of the glass melt in the reactor.

[0059] In an embodiment, the step of withdrawing the glass melt from the reactor is conducted at a withdrawal temperature of at least T3, where T3 is the temperature at which the glass melt composition is heated to 100°C. 3 The temperature at which the glass melt has a viscosity of 1000 dPa·s is reached. The glass melt is withdrawn from the reactor via a discharge opening.

[0060] In a preferred embodiment, the step of withdrawing the glass melt from the reactor is conducted at a withdrawal temperature greater than or equal to T4 but less than T3, where T4 is the temperature at which the glass melt composition is heated to 100°C. 4 The temperature at which the glass melt has a viscosity of 1000 dPa·s is reached. The glass melt is withdrawn from the reactor via a discharge opening.

[0061] According to another preferred embodiment, the step of withdrawing the glass melt from the reactor is carried out at a withdrawal temperature of at least 50° C. above T4, preferably 50-130° C. above T4.

[0062] In an embodiment, the method includes adjusting the withdrawal temperature. The adjustment of the withdrawal temperature is performed to control the withdrawal rate of the glass melt with a tolerance of 2% or less, or 1% or less. The withdrawal temperature of the glass melt can be measured by an IR pyrometer (6). The withdrawal temperature according to the present disclosure is measured by the IR pyrometer inside the furnace at a defined point on the surface of the sidewall, the defined point being above the surface of the glass melt.

[0063] Optionally, the method may include adjusting the pressure above the glass melt. Adjusting the pressure above the glass melt is performed to control the withdrawal rate of the glass melt with a tolerance of 2% or less, preferably 1% or less. Adjusting the pressure above the glass melt may include protecting the hermetic seal of the reactor and / or using compressed air to compensate for the pressure drop at the lower discharge opening. Preferably, the pressure above the glass melt is measured by a pressure sensor. Such sensors are known to those skilled in the art and are commercially available. The pressure above the glass melt is therefore related to the conditions in the reactor and above the glass melt.

[0064] The rate at which the glass melt is withdrawn from the reactor quantifies the amount of glass melt leaving the reactor per unit time and is expressed as a volumetric flow rate in ml / min.

[0065] Optionally, the method for manufacturing a glass rod provides a glass rod or set of glass rods according to the present disclosure.

[0066] In one embodiment, the reactor is a batch reactor. In an alternative embodiment, the reactor is a continuous reactor. Preferably, the reactor is a batch reactor.

[0067] In one embodiment, heating frits in a reactor to obtain a glass melt includes providing a batch of oxides, which may be selected from the list of SiO2, BO, Al2O3, one or more alkaline earth metal oxides, and one or more alkali metal oxides, or other suitable frits, and heating the batch to melt. According to a preferred embodiment, the batch of oxides is selected from the group consisting of SiO2, BO, Al2O3, one or more alkaline earth metal oxides, and one or more alkali metal oxides.

[0068] In one embodiment, the glass melt is 2.5 The melt is at least partially heated to a temperature T2.5, defined as the temperature at which the glass has a viscosity of 0.01 dPa·s. The melting temperature T2.5 can provide a sufficiently low viscosity to allow for a uniform distribution of the oxides fed with the raw materials, resulting in a homogeneous glass melt.

[0069] In one embodiment, the glass melt is at least partially heated to a temperature T2.3. Alternatively, in one embodiment, the glass melt is at least partially heated to a temperature T2.1 or less. Alternatively, in one embodiment, the glass melt is at least partially heated to a temperature between T2.5 and T2.1.

[0070] In one embodiment, the step of at least partially heating the glass melt to a temperature T2.5 is carried out in a batch or continuous reactor for a time sufficient to establish a homogeneous glass melt. Depending on the raw materials selected and the type of reactor (continuous or batch), it is known to those skilled in the art how to establish a temperature T2.5 to obtain a homogeneous glass melt. In one embodiment, the entire glass melt in the reactor is heated to a temperature T2.5. In one embodiment, the entire glass melt in the reactor is heated to a temperature between T2.5 and T2.1. The temperature in the reactor can be assessed and controlled using a suitable temperature probe capable of operating at the high temperatures required for the glasses according to the present invention.

[0071] It is preferable that the viscosity of the glass melt not fall below 100 dPa·s. Heating the glass to a very low viscosity increases the erosion of the melting vessel walls and can introduce impurities into the glass composition. Furthermore, low viscosities correspond to very high temperatures, which require high power consumption, which is undesirable due to economic disadvantages.

[0072] The production conditions include controlling the withdrawal of the glass melt from the reactor at the withdrawal temperature and at the glass melt withdrawal rate, increasing the withdrawal temperature to control the glass melt withdrawal rate, and / or adjusting the pressure above the glass melt to control the glass melt withdrawal rate.

[0073] The drawing temperature of the glass melt is related to the temperature of said glass melt, which can be measured using a suitable temperature probe, for example an IR pyrometer, which makes it possible to monitor and control the process in order to maintain the intended temperature tolerances.

[0074] In one embodiment of the method, the glass melt is withdrawn at a withdrawal temperature of at least 50°C above T4, preferably 50 to 130°C above T4, with a tolerance of 10°C, preferably 5°C, and most preferably 3°C, wherein withdrawal of the glass melt from the reactor is preferably carried out through a discharge opening. In one embodiment, the discharge opening is a die having a conical internal shape. Advantageously, the die can be designed and / or used to control the fluid flow characteristics as the glass melt exits the reactor. Thus, the die allows for control of the withdrawal rate of the glass melt as well as the shape of the glass melt stream exiting the reactor. The withdrawal rate of the glass melt can be expressed as a volumetric flow rate in ml / min, which relates to the volume of glass melt leaving the reactor per unit time.

[0075] In one embodiment, the discharge opening can be heated. Those skilled in the art recognize that the high temperatures required for glass production can result in temperature gradients in the glass melt within the reactor. Therefore, it is advantageous to monitor the temperature of the glass melt in the reactor, optionally including the discharge opening, and control and / or adjust the temperature via an independent heating means at the discharge opening, if necessary. Such an independent heating means can be, for example, an electromagnetic coil. In one embodiment of the method, the withdrawal temperature is increased to control the withdrawal rate of the glass melt with a tolerance of 2% or less, preferably 1% or less. In one embodiment of the method, the pressure above the glass melt is adjusted to control the withdrawal rate of the glass melt with a tolerance of 2% or less, preferably 1% or less.

[0076] In one embodiment of the method, increasing the withdrawal temperature to control the withdrawal rate of the glass melt comprises increasing the withdrawal temperature in 1°C increments and increasing the withdrawal temperature by 30°C, 20°C, 10°C, 5°C, or 3°C during withdrawal of the glass melt. It is advantageous to control the withdrawal of the glass melt from the reactor within narrow rate (volumetric flow rate) boundaries and thus work with a nearly constant glass mass flow exiting the reactor to minimize possible geometric deviations in the resulting glass rod.

[0077] The withdrawal of glass melt from the reactor can be described and quantified in terms of volumetric flow rate in terms of "ml / min." The withdrawal rate of glass melt from the reactor should be fairly constant. For a given average withdrawal rate, a 1% tolerance means that the maximum and minimum withdrawal rates should not deviate from each other by more than 1% based on the average withdrawal rate.

[0078] It is advantageous to control the glass melt to be drawn at a drawing temperature at least 50°C above T4 with a tolerance of 10°C, or 5°C, or 3°C, because the viscosity must be large enough to provide flow conditions for the glass melt during the drawing step into a rod. At the same time, the temperature deviation of the glass melt during the drawing step must be kept small, for example, to a tolerance of 10°C, or 5°C, or 3°C, to avoid inhomogeneities in the glass melt composition and viscosity of the glass melt. A tolerance of, for example, 10°C during drawing means that the maximum and minimum temperatures cannot deviate from each other by more than 10°C during a single process run to produce a glass rod of one particular glass composition.

[0079] In one embodiment, the glass melt is drawn at a drawing temperature of 50 to 130°C above T4, with a tolerance of 10°C, or 5°C, or 3°C. The exact temperature at which the glass melt is drawn can depend on the glass composition and the type and geometric characteristics of the reactor. It can be advantageous to control the glass melt drawing temperature within a narrow range of a tolerance of 10°C, or 5°C, or 3°C. This temperature control is usually automated, but can also be further controlled by direct operator direction during production. For example, at the beginning of the process, it may be necessary or necessary to reduce the temperature by 20°C or less if, for example, the viscosity of the glass composition is too high, and / or to implement feedback control by 50°C or less.

[0080] In one embodiment, the glass melt is drawn at a drawing temperature of 50 to 130° C. above T4, preferably 55 to 125° C. above T4, more preferably 60 to 120° C. above T4, more preferably 65 to 115° C. above T4, even more preferably 70 to 110° C. above T4, even more preferably 75 to 105° C. above T4, and most preferably 80 to 100° C. above T4. In one embodiment, the glass melt is drawn at a temperature of 50° C. or more above T4, preferably 55° C. or more above T4, more preferably 60° C. or more above T4, more preferably 65° C. or more above T4, even more preferably 70° C. or more above T4, even more preferably 75° C. or more above T4, and most preferably 80° C. or more above T4. In one embodiment, the glass melt is drawn at a temperature of not more than 130°C above T4, preferably not more than 125°C above T4, more preferably not more than 120°C above T4, more preferably not more than 115°C above T4, even more preferably not more than 110°C above T4, even more preferably not more than 105°C above T4, and most preferably not more than 100°C above T4.

[0081] In one embodiment, the glass melt is drawn from the reactor through a die as a discharge opening. A suitable die for drawing the glass melt comprises an alloy, wherein the alloy comprises 90% by mass or more of iridium. Advantageously, the die can enable a smooth manufacturing process.

[0082] Cooling the glass melt to obtain a glass rod is performed after the glass melt passes through the discharge opening. Advantageously, process conditions are established so that the average cooling rate of the glass rod is 2000 K / h or less until the T4 temperature is reached, which maintains the homogeneity of the glass composition and the uniformity of the glass rod. After the glass melt is cooled to the T4 temperature, subsequent cooling can proceed at a faster cooling rate. In one embodiment, the average cooling rate of the glass rod is 1000 K / h or less, preferably 500 K / h or less, more preferably 200 K / h or less, and most preferably 5 K / h or less. In one embodiment, the cooling rate of the glass rod is 1 K / h or more, preferably 2 K / h or more, and most preferably 3 K / h or more. In one embodiment, the cooling rate of the glass rod is 1 K / h to 20 K / h, preferably 2 K / h to 15 K / h, and most preferably 3 K / h to 10 K / h.

[0083] The forming of the glass melt to obtain a glass rod is primarily performed at the discharge opening, i.e., when the glass melt leaves the reactor. In one embodiment, the glass melt has a glass composition having a T4 temperature of 1400°C or higher, where T4 is the glass melt composition at a temperature of 1000°C or higher. 4The temperature at which the glass melt has a viscosity of 1000 dPa·s. In one embodiment, the glass melt has a glass composition having a T4 temperature of 1400°C or higher, preferably 1450°C or higher, more preferably 1500°C or higher, and most preferably 1550°C or higher. In one embodiment, the glass melt has a glass composition having a T4 temperature of 1900°C or lower, preferably 1850°C or lower, more preferably 1800°C or lower, and most preferably 1750°C or lower. In one embodiment, the glass melt has a glass composition having a T4 temperature of 1400°C to 1900°C, preferably 1450°C to 1850°C, more preferably 1500°C to 1800°C, and most preferably 1550°C to 1750°C.

[0084] In one embodiment of the method, the glass melt is withdrawn from the reactor at a volumetric flow rate of 15 to 150 ml / min, preferably 25 to 120 ml / min, and most preferably 50 to 100 ml / min. In one embodiment of the method, the glass melt is withdrawn from the reactor at a volumetric flow rate of 15 ml / min or more, preferably 25 ml / min or more, and most preferably 50 ml / min or more. In one embodiment of the method, the glass melt is withdrawn from the reactor at a volumetric flow rate of 150 ml / min or less, preferably 120 ml / min or less, and most preferably 100 ml / min or less.

[0085] In one embodiment of the method, which is optionally a batch process, the method further comprises interrupting the withdrawal of glass melt from the reactor, preferably operated as a batch reactor, before reaching a consumption of 90% by volume, preferably 80% by volume, more preferably 70% by volume, even more preferably 60% by volume, and most preferably 50% by volume of the glass melt. In a batch process, an initial glass melt is produced, and at some point it becomes possible to withdraw the glass melt from the reactor. Before the start of withdrawal, the amount of glass melt is 100% normalized to the volume. Glass consumption is to be understood as the % amount of glass melt withdrawn from the reactor, i.e., formed into a glass rod. Advantageously, when the method is carried out batchwise, at least 50% by volume of the glass melt from the reactor is used and can be formed into a glass rod without loss of quality.

[0086] Glass composition In one embodiment, the glass rod comprises the following components in weight percent: 70.0%~90.0% SiO2, 0.0%~25.0% B2O3, 0.0% to 10.0% Al2O3, 0.0% to 10.0% of one or more alkaline earth metal oxides, 0.0% to 7.0% of one or more alkali metal oxides The present invention also includes glass compositions containing one or more or all of the following, provided that SiO2 is always present in said glass composition.

[0087] In this disclosure, references to glass and glass compositions are to be understood as the same subject matter.

[0088] In one embodiment, the glass contains SiO2 in an amount of 70.0% by mass or more, preferably 72.0% by mass or more, more preferably 74.0% by mass or more, even more preferably 76.0% by mass or more, even more preferably 78.0% by mass or more, and most preferably 80.0% by mass or more. In one embodiment, the glass contains SiO2 in an amount of 90.0% by mass or less, preferably 89.0% by mass or less, more preferably 88.0% by mass or less, even more preferably 87.0% by mass or less, and most preferably 86.0% by mass or less. In one embodiment, the glass contains SiO2 in an amount of 70.0% to 90.0% by mass, preferably 72.0% to 89.0% by mass, more preferably 74.0% to 88.0% by mass, even more preferably 76.0% to 87.0% by mass, and most preferably 78.0% to 86.0% by mass.

[0089] In one embodiment, the glass is a borosilicate glass containing SiO2 in an amount of 70.0% to 90.0% by weight, preferably 72.0% to 89.0% by weight, more preferably 74.0% to 88.0% by weight, even more preferably 76.0% to 87.0% by weight, and most preferably 78.0% to 86.0% by weight.

[0090] In one embodiment, the glass comprises, in weight percent, one or more of the following components: 70.0% to 90.0% SiO2, 0.0% to 25.0% B2O3, 0.0% to 10.0% Al2O3, 0.0% to 10.0% of one or more alkaline earth metal oxides, and 0.0% to 7.0% of one or more alkali metal oxides.

[0091] In one embodiment, the glass comprises one or more or all of the following components in weight percent: 75.0% to 87.0% SiO2, 8.0% to 22.0% B2O3, 1.0% to 7.0% Al2O3, 0.25% to 5.0% of one or more alkaline earth metal oxides, and 0.0% to 5.0% of one or more alkali metal oxides.

[0092] For purposes of the present invention, alkali metal oxides are specifically meant to include Li2O, Na2O, and K2O, and alkaline earth metal oxides are specifically meant to include MgO, CaO, BaO, and SrO.

[0093] In one embodiment, the glass comprises, by weight, 0.0% to 10.0%, for example 1.0% to 9.0%, preferably 2.0% to 8.0%, more preferably 3.0% to 7.0%, and most preferably 4.0% to 6.0% of one or more alkaline earth metal oxides.

[0094] In one embodiment, the glass comprises, by weight, 0.0% to 7.0%, for example 0.5% to 6.5%, preferably 1.0% to 6.0%, more preferably 1.5% to 5.5%, and more preferably 2.0% to 5.0% of one or more alkaline earth metal oxides.

[0095] In one embodiment, the glass comprises, in weight percent: SiO2 70.0%~90.0% B2O3>0.0%~25.0% Al2O3>0.0%~10.0% BaO 0.0%~5.0% CaO 0.0%~3.0% K2O 0.0%~5.0% Na2O 0.0%~5.0% Li2O 0.0%~1.0% Includes.

[0096] In one embodiment, the glass contains B2O3 in an amount of 1.0% by weight or more, preferably 2.0% by weight or more, more preferably 4.0% by weight or more, even more preferably 6.0% by weight or more, and most preferably 8.0% by weight or more. In one embodiment, the glass contains B2O3 in an amount of 25.0% by weight or less, preferably 22.0% by weight or less, more preferably 20.0% by weight or less, even more preferably 18.0% by weight or less, even more preferably 15.0% by weight or less, and most preferably 12.0% by weight or less. In one embodiment, the glass contains B2O3 in an amount of 1.0% to 25.0% by weight, preferably 2.0% to 22.0% by weight, even more preferably 4.0% to 20.0% by weight, even more preferably 6.0% to 18.0% by weight, and most preferably 8.0% to 15.0% by weight.

[0097] In one embodiment, the glass contains Al2O3 in an amount of 1.0% by weight or more, preferably 2.0% by weight or more, more preferably 3.0% by weight or more, and most preferably 4.0% by weight or more. In one embodiment, the glass contains Al2O3 in an amount of 10.0% by weight or less, preferably 9.0% by weight or less, more preferably 8.0% by weight or less, even more preferably 7.0% by weight or less, and most preferably 6.0% by weight or less. In one embodiment, the glass contains Al2O3 in an amount of 0.0% to 10.0% by weight, preferably 1.0% to 9.0% by weight, more preferably 2.0% to 8.0% by weight, even more preferably 3.0% to 7.0% by weight, and most preferably 4.0% to 6.0% by weight.

[0098] In one embodiment, the glass contains, by mass, 0.0% to 5.0%, for example, 0.5% to 4.5%, preferably 1.0% to 4.0%, more preferably 1.5% to 3.5%, and most preferably 2.0% to 3.0% BaO. In one embodiment, the glass contains, by mass, 0.0% or more, preferably 0.5% or more, more preferably 1.0% or more, even more preferably 1.5% or more, and most preferably 2.0% or more BaO. In one embodiment, the glass contains, by mass, 5.0% or less, preferably 4.5% or less, more preferably 4.0% or less, even more preferably 3.5% or less, and most preferably 3.0% or less BaO.

[0099] In one embodiment, the glass contains 0.0% to 3.0% CaO by weight, e.g., 0.2% to 2.8%, 0.4% to 2.6%, 0.6% to 2.4%, 0.8% to 2.2%, or 1.0% to 2.0%. In one embodiment, the glass contains 0.0% or more CaO by weight, preferably 0.2% or more, more preferably 0.4% or more, even more preferably 0.6% or more, even more preferably 0.8% or more, and most preferably 1.0% or more. In one embodiment, the glass contains 3.0% or less CaO by weight, preferably 2.8% or less, more preferably 2.6% or less, even more preferably 2.4% or less, even more preferably 2.2% or less, and most preferably 2.0% or less.

[0100] In one embodiment, the glass contains 0.0% to 5.0% by weight of KO, e.g., 0.5% to 4.5%, 1.0% to 4.0%, 1.5% to 3.5%, or 2.0% to 3.0%. In one embodiment, the glass contains 0.0% or more by weight of KO, preferably 0.5% or more, more preferably 1.0% or more, even more preferably 1.5% or more, and most preferably 2.0% or more. In one embodiment, the glass contains 5.0% or less by weight of KO, preferably 4.5% or less, more preferably 4.0% or less, even more preferably 3.5% or less, and most preferably 3.0% or less.

[0101] In one embodiment, the glass contains 0.0% to 5.0% NaO by weight, e.g., 0.5% to 4.5%, 1.0% to 4.0%, 1.5% to 3.5%, or 2.0% to 3.0%. In an alternative embodiment, the glass contains 0.0% to 3.0% NaO by weight, e.g., 0.1% to 2.5%, 0.2% to 2.0%, 0.3% to 1.5%, or 0.4% to 1.0%. In one embodiment, the glass contains 0.0% or more NaO by weight, preferably 0.1% or more, more preferably 0.2% or more, even more preferably 0.3% or more, and most preferably 0.4% or more. In one embodiment, the glass contains 3.0% or less NaO by weight, preferably 2.5% or less, more preferably 2.0% or less, even more preferably 1.5% or less, and most preferably 1.0% or less.

[0102] In one embodiment, the glass contains 0.0% to 1.0% by weight of LiO, for example, 0.1% to 0.9%, 0.2% to 0.8%, 0.3% to 0.7%, or 0.4% to 0.6%. In one embodiment, the glass contains 0.0% or more by weight of LiO, preferably 0.1% or more, more preferably 0.2% or more, even more preferably 0.3% or more, and most preferably 0.4% or more. In one embodiment, the glass contains 1.0% or less by weight of LiO, preferably 0.9% or less, more preferably 0.8% or less, even more preferably 0.7% or less, and most preferably 0.6% or less.

[0103] In one embodiment, the glass contains 1000 ppm by weight or less of Fe2O3, preferably 500 ppm by weight or less of Fe2O3, more preferably 200 ppm by weight or less of Fe2O3, even more preferably 100 ppm by weight or less of Fe2O3, even more preferably 50 ppm by weight or less of Fe2O3, and most preferably 20 ppm by weight or less of Fe2O3. In one embodiment, the glass contains 1 ppm by weight or more of Fe2O3, or 2 ppm by weight or more of Fe2O3, or 3 ppm by weight or more of Fe2O3, or 5 ppm by weight or more of Fe2O3, or 7 ppm by weight or more of Fe2O3, or 10 ppm by weight or more of Fe2O3. In one embodiment, the glass contains 1 to 1000 ppm (by mass) of Fe2O3, or 2 to 500 ppm (by mass) of Fe2O3, or 3 to 200 ppm (by mass) of Fe2O3, or 5 to 100 ppm (by mass) of Fe2O3, or 7 to 50 ppm (by mass) of Fe2O3, or 10 to 20 ppm (by mass) of Fe2O3.

[0104] In one embodiment, the glass comprises, in weight percent: SiO2 75.0%~87.0% B2O38.0%~22.0% Al2O3 1.0%~7.0% BaO 0.0%~3.0% CaO 0.0%~2.0% K2O 0.0%~3.0% Na2O 0.0%~3.0% Li2O 0.0%~1.0% Includes.

[0105] In one embodiment, the glass comprises, in weight percent: SiO2 77.0%~87.0% B2O38.0%~13.0% Al2O3 3.0% to 7.0% BaO 0.0%~3.0% CaO 0.0%~2.0% K2O 0.0%~3.0% Na2O 0.0%~1.0% Li2O 0.0%~1.0% Includes.

[0106] In one embodiment, the glass is free of one or more or all of lithium, magnesium, potassium, calcium, sodium, lead, arsenic, and antimony.

[0107] When this description refers to a glass that is free of a component, does not contain a particular component, or includes the hypothetical case of 0% by weight of that component, it should be understood that this component may be present at most as an impurity. This means that it is not added in a significant amount and is not intentionally added. The term "component" refers to the elemental species itself, as well as any molecules containing that element, and in particular the oxides of the respective compounds. An insignificant or insubstantial amount should be understood as less than 100 ppm, preferably less than 50 ppm, and most preferably less than 10 ppm, based on the total weight of all intentionally added components.

[0108] In one embodiment, the glass composition has a viscosity of 0.95×10 measured in the temperature range of 20 to 300° C. and specified in accordance with ISO 7991:1987. -6 ~3.20×10 -6 / K. In one embodiment, the glass composition has a thermal expansion coefficient of at least 0.95×10 -6 / K, preferably at least 1.00 × 10 -6 / K, more preferably at least 1.05×10 -6 / K, and even more preferably at least 1.10 × 10 -6 / K, and even more preferably at least 1.20 × 10 -6 / K, and most preferably at least 1.50×10 -6 / K. In one embodiment, the glass composition has a thermal expansion coefficient of 3.20×10 -6 / K or less, preferably 3.00 × 10 -6 / K or less, more preferably 2.70×10 -6 / K or less, and even more preferably 2.20 × 10 -6 / K or less, most preferably 2.00 × 10 -6 / K or less. In one embodiment, the glass composition has a thermal expansion coefficient of 0.95×10 -6 ~3.20×10 -6 / K, preferably 1.00 × 10 -6 ~3.00×10 -6 / K, more preferably 1.05 × 10 -6 ~2.70×10 -6 / K, and even more preferably 1.10 × 10 -6 ~2.20×10 -6 / K, and even more preferably 1.20 × 10 -6 ~2.20×10 -6 / K, and most preferably 1.50 x 10 -6 ~2.00×10 -6 / K.

[0109] In one embodiment, the glass composition has a transition temperature of 600 to 750°C as measured by ISO 7884-8:1987. In one embodiment, the glass composition has a transition temperature of at least 600°C, preferably at least 615°C, more preferably at least 635°C, such as at least 650°C, or at least 680°C, or at least 695°C. In one embodiment, the glass composition has a transition temperature of 750°C or less, preferably 730°C or less, and most preferably 710°C or less. In one embodiment, the glass composition has a transition temperature of 600 to 750°C, preferably 615 to 730°C, and most preferably 635 to 710°C. [Example]

[0110] Glass composition The following glass compositions 1-5 are examples of glass compositions that can be fabricated into glass rods of this disclosure, which are further characterized by their coefficient of thermal expansion (CTE) and T4 temperature.

[0111] [Table 1]

[0112] - means that this compound was not detectable in the resulting glass rod.

[0113] Glass rod manufacturing FIG. 3 shows a reactor (1) with a lower discharge opening (2). Glass raw materials are heated in the reactor (1) to obtain a glass melt (3). A conveying means (4) assists in the withdrawal of a glass rod (5) downstream of the reactor, i.e., after the glass melt (3) leaves the reactor (1) through the lower discharge opening (2). The lower discharge opening (2) is independently heated (e.g., by an electromagnetic coil, shown as a circle) to ensure a constant and uniform glass flow. The lower discharge opening (2) can be a nozzle (referred to herein as a "die") or a duct. The withdrawal temperature of the glass melt (3) is measured using an optional IR pyrometer (6). The pressure above the glass melt is measured using an optional pressure sensor (7). The reactor includes an optional upper heater (8), preferably a gas burner, located above the melting surface.

[0114] 3.0 g / cm with lower discharge opening (iridium die) 3 A reactor made of a Zr compound having a density greater than 1000 kJ / cm2 was used to heat the glass frit of composition 1. The glass was heated to a temperature of T2.5 using an upper heater and held at this temperature for about 20 hours without stirring or other mechanical agitation, then drawn and formed into a glass rod. The lower discharge opening was an iridium die and had a distance of about 20 cm from any part of the reactor wall. The glass rod was continuously sorted into trays. The following table shows the data obtained from the glass rod.

[0115] [Table 2]

[0116] From the above data, it is clear that the ZrO2 concentration increases throughout the withdrawal of the melt from the reactor. We have found that during withdrawal, zirconium compounds such as zirconium oxide, zirconium silicate and / or Zr 4+The hypothesis is that ions are progressively released from the reactor walls into the melt. Initially, the volume of glass melt leaving the reactor through the die originates from the center of the reactor, far away from the walls. As more glass melt is withdrawn from the reactor, the volume originating closer to the walls leaves the reactor and forms into a glass rod. At some point during withdrawal, the volume directly adjacent to the wall leaves the melt through the die. These volumes then deposit Zr into the glass rod. 4+ This results in scratches containing ions. 4+ The amount of ions was normalized to the amount of the corresponding oxide, and the highest local concentration of ZrO2 was Zr max It is quite surprising that this happens so suddenly. In this example, the Zr max is still good, while in tray 22, Zr max rises to very high values.

[0117] Figure 1 shows the cross section of a glass rod under a microscope after heat treating the rod at 1200 °C for 10 minutes and cooling the rod at 2 K / h. This heat treatment makes visible areas of very high ZrO2 concentration, which would otherwise remain invisible upon microscopic examination. The arrows indicate ZrO2 contamination streaks. These areas of very high ZrO2 concentration would cause mechanical failure when used in a flash lamp, possibly due to different thermal expansion behavior. For comparison, Figure 2 shows the cross section of a glass rod that underwent the same heat treatment but with a lower ZrO2 content. max 1 shows a glass rod having a

[0118] The present inventors have found that various means can be used to max / Zr avg ratio and low Zr maxIt has been found that this contributes to achieving the above. First, the melt should be slowly homogenized by holding it at a temperature of about T2.5 for a long time, preferably at least 10 hours. Furthermore, it is beneficial to reduce or preferably avoid mechanical stirring of the glass melt, for example by stirring. Furthermore, the use of an upper burner, preferably a gas burner, instead of an electrode helps to reduce convection in the glass melt and helps to keep the wall parts cool. Furthermore, it is advantageous not to use the entire initial melt volume to produce a glass rod. Instead, the allowable Zr max Furthermore, it is advantageous to position the die through which the withdrawal is carried out at the bottom of the reactor, at a sufficient distance from the wall.

[0119] Zr max and Zr avg Measurement of Sample preparation Glass rod samples were cut to size using a diamond saw. The samples were then ground and polished to a final dimension of 3 mm. Finally, the samples were cleaned with ethanol in an ultrasonic bath. Loosely adhering particles were blown off before measurement.

[0120] In this disclosure, the following Zr max and Zr avg Measurements used: Zr max and Zr avg are identified using LA-ICP-MS, which uses a laser beam with λ = 213 nm. Material is removed from the sample by the laser and introduced into the ICP-MS in a flow of inert gas. The material is evaporated and ionized at 6000-8000 °C in the spectrometer, and then analyzed by MS. The instrument used was a PerkinElmer ICP mass spectrometer, NexION 300X.

[0121] For the analysis of the sample, four ablation runs were performed with a crater diameter of 100 μm each over a depth of approximately 20 μm. In the LA-ICP-MS analysis, the analyte zirconium (Zr90 ) intensity ratio for each ablation time / depth, and the internal standard (silicon Si 28 ) intensity was measured.

[0122] Quantification of the measured intensity ratios of the samples was performed against calibration using various certified solid standards with known zirconium content.

[0123] Zr max is identified at the location of the highest local concentration of ZrO2. Three measurements are taken and the value with the highest ZrO2 concentration is taken as Zr max / Zr avg is used to calculate

[0124] Zr avg is determined by taking at least three different measurements on the end portion of the glass rod and calculating the average value.

Claims

1. Length l rod 100 to 1600 mm, and ZrO 2 The highest local concentration of ZrO and the average 2 Concentration ratio Zr max / Zr avg less than 8.0, ZrO 2 The highest local concentration of Zr max A glass rod having a SiO2 content of less than 5500 ppm.

2. ZrO 2 Average concentration of Zr avg 2. The glass rod according to claim 1, wherein the Cr content is less than 3500 ppm, preferably less than 2600 ppm.

3. Zr avg is at least 200 ppm, preferably 300 ppm to 3000 ppm, and / or Zr max is less than 2000 ppm, preferably less than 1000 ppm, and / or Zr max / Zr avg is less than 7.0, preferably less than 5.0, and most preferably less than 3.0; 3. The glass rod according to claim 1.

4. 4. The glass rod according to claim 1, which contains less than 100 ppm of tungsten and / or molybdenum and / or less than 10 ppm of iridium.

5. At least 70.0% by weight of SiO 2 The glass rod according to any one of claims 1 to 4, comprising:

6. One or more or all of the following ingredients: 70.0 to 90.0% by mass of SiO 2 , 0.0 to 25.0% by mass of B 2 O 3 , 0.0 to 10.0% by weight of Al 2 O 3 , 0.0 to 10.0% by weight of one or more alkaline earth metal oxides; 0.0 to 7.0% by weight of one or more alkali metal oxides The glass rod according to any one of claims 1 to 5, comprising:

7. 7. The glass rod according to claim 1, having a transmission of at least 90% at a reference thickness of 10 mm, measured over the wavelength range of 350 to 450 nm.

8. the glass rod has a central portion and end portions, the central portion being defined as the portion of the rod located at a distance less than 1 / 2 r from the center of mass of the cross section of the rod, where r is the radius of the cross section, and the end portions being defined as the portion of the glass rod located at a distance of at least 1 / 2 r from the center of mass of the cross section of the rod; ZrO in the center of the glass rod 2 The concentration of ZrO 2 8. The glass rod according to claim 1, wherein the concentration is greater than 1000 ppm.

9. Zr max The glass rod according to claim 8 , wherein

10. Length l rod is 800 to 1100 mm, and The thickness of the glass rod is in the range of 2.0 mm to 5.0 mm, and The homogeneity of the average linear thermal expansion coefficient in the temperature range of 30 to 300°C is less than 0.08 ppm / K. The glass rod according to any one of claims 1 to 9.

11. A set of glass rods comprising at least 40 glass rods according to any one of claims 1 to 10.

12. 11. Use of a glass rod according to any one of claims 1 to 10 for joining a metal article to a glass member.

13. A method for manufacturing a glass rod, comprising: providing a reactor (1) comprising a lower discharge opening (2) and one or more reactor walls enclosing a reactor volume; and a step of heating glass raw materials in the reactor to obtain a glass melt (3), the glass melt (3) having a glass composition with a T4 temperature of 1400°C or more, where T4 is the glass melt composition having a viscosity of 10 4 the temperature having a viscosity of 1000 dPa·s; and The glass melt (3) is heated to a temperature of 1000°C. 2.5 at least partially heating to a temperature T2.5, defined as the temperature having a viscosity of 100 MPa s, and holding this temperature for a holding time of at least 10 hours; withdrawing the glass melt (3) from the reactor (1), and - cooling and / or shaping the glass melt (3) to obtain one or more glass rods (5) according to any one of claims 1 to 10. The method comprising:

14. only up to 90% by volume, preferably up to 70% by volume, and most preferably up to 50% by volume of the volume of the initial glass melt is used to form said glass melt (3) into a glass rod, and / or the lower discharge opening (2) is located at a distance of at least 10 cm from the reactor wall, and / or the glass melt (3) is not stirred during the holding time, and / or the glass melt (3) is not stirred during withdrawal, and / or the reactor comprises a top heater, preferably a gas burner, located above the melt surface; The method of claim 13.

15. interrupting the withdrawal of the glass melt (3) from the reactor (1) before 90% by volume, preferably 70% by volume, and most preferably 50% by volume of the initial glass melt volume has been withdrawn, and / or heating the frit using an upper heater, preferably a gas burner, placed above the melting surface, and / or heating the glass melt (3) using a top heater, preferably a gas burner, placed above the glass melting surface, and / or the withdrawal of the glass melt (3) from the reactor mainly comprises, in particular only, that portion of the glass melt (3) that is at a distance of at least 5 cm from the wall of the reactor (1); 15. The method of claim 13 or 14, comprising:

16. the reactor (1) comprises a refractory material, the refractory material comprising zirconium oxide and / or zirconium silicate, and optionally the melting furnace is essentially free of molybdenum and / or tungsten and / or iridium, and / or the contact surface of the reactor (1) in contact with the glass melt contains more than 70% by weight of ZrO 2 and / or the contact surface of the reactor in contact with the glass melt (3) comprises a sintered material having more than 80% by weight, preferably more than 90% by weight, and most preferably more than 95% by weight of zirconium silicate, 16. The method according to any one of claims 13 to 15.

Images