Low bio-persistent high temperature resistant inorganic fiber

Abstract

To provide a high temperature resistant inorganic fiber that provides, while improving heat stability of calcia-magnesia-silicate chemistry, improved melting characteristics and fiberization characteristics, and a product quality.SOLUTION: A high temperature resistant inorganic fiber includes 72-77.3 wt.% silica; 10.2-15 wt.% magnesia; 12.4-17 wt.% calcia; 0-1.5 wt.% alumina; and 0-0.6 wt.% total alkali oxides. The fiber possesses a use temperature of at least 1260°C and exhibits a shrinkage of greater than 5% after exposure to a temperature of 1400°C for 24 hours.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] This application claims the benefit of U.S. Provisional Patent Application No. 63 / 124,518, entitled "LOW BIO-PERSISTENT HIGH TEMPERATURE RESISTANT INORGANIC FIBERS," filed December 11, 2020, which is incorporated herein by reference in its entirety.

[0002] The present disclosure relates to inorganic fibers. More particularly, the present disclosure relates to low biopersistence, high temperature resistant alkaline earth silicate (AES) fiber chemistries. [Background technology]

[0003] AES fibers are primarily composed of alkaline earth oxides (e.g., MgO, CaO, etc.) and silica, often combined with small amounts of alumina, alkali oxides, or other additives to improve fiberization performance. Through careful fiber construction design, AES fibers can provide high-temperature thermal stability, important for thermal insulation applications, and low biopersistence, important for the safety and health of fiber and textile product manufacturers and end users.

[0004] To be fiberizable (i.e., capable of being formed into fibers), AES fiber compositions typically contain a silica content in the range of 60-85% by weight. Generally, the higher the silica content of an AES fiber composition, the higher its melting point. Therefore, AES fibers with a high silica content (i.e., greater than 77% by weight) can provide excellent thermal stability at temperatures above 1200°C. ISOFRAX® and ISOFRAX® 1400 (available from Unifrax I LLC) contain primarily magnesia silicate chemistry with a silica content greater than 77% by weight and can perform at temperatures above 1260°C.

[0005] However, the production of high-silica AES fibers is challenging due to their extremely high melting points and "short" viscosity curves. The "short" viscosity curve means that the temperature range suitable for fiberization is narrow, posing significant challenges not only to fiber quality but also to manufacturing. High silica content leads to high melting points for AES chemistries. For example, magnesia-silica chemistry containing 79% silica by weight has a liquidus temperature above 1800°C and a low viscosity at the liquidus temperature of only about 50 poise. Due to the high liquidus temperature, high temperatures are required to melt and fiberize such melts. For example, the raw material for the aforementioned magnesia-silica chemistry must be heated to a temperature of 2100°C to melt and fiberize it into magnesia-silica fibers. Such high melting points pose severe challenges to furnace conditions and equipment, significantly reducing the lifespan of equipment such as furnace linings, electrodes, and fiberizers. High-temperature insulating wool is typically produced by melting the raw material in a submerged electrode furnace, with the melt stream exiting the bottom for fiberization. High melting points or operating temperatures accelerate corrosion of electrodes, furnace walls, and spinning wheels (fiberization processes using the spinning method), shortening their lifespan. Also, when melting at high temperatures, the large temperature gradient between the melt and the cooling medium means that most of the input energy is transferred to the cooling medium surrounding the furnace. [Brief explanation of the drawings]

[0006] [Figure 1] FIG. 1 is a graph showing temperature-dependent viscosity curves of a high-silica magnesia silica fiber (Comparative Example C4), a high-silica calcia magnesia silica fiber (Comparative Example C6), and a low-silica calcia magnesia silica fiber (Example 2). [Figure 2] FIG. 2 is a graph showing the liquidus temperature of calcia-magnesia-silica fibers as a function of silica content in the fibers. Detailed Description of the Invention

[0007] The present disclosure improves the thermal stability of calcia-magnesia-silicate chemistries while providing improved melting and fiberization properties and product quality. According to some aspects of the present disclosure, calcia-magnesia-silicate fibers can exhibit performance such as extremely low shrinkage at temperatures above 1260°C, improved blanket tensile strength and fiber index, improved melting and fiberization properties, and / or reduced energy consumption during production.

[0008] The inorganic fibers of the present disclosure are low biopersistent, meaning that they exhibit low biopersistence in physiological fluids, i.e., they are at least partially soluble in such fluids, such as simulated lung fluid, during in vitro testing. Biopersistence is measured by the rate at which mass is lost from the fiber (ng / cm) under conditions simulating the temperature and chemical conditions found in the human lung. 2 The test can be performed by measuring the thermal conductivity (Tc) of the fiber (Tc) during 6 hours. The test is performed by exposing approximately 0.1 g of de-shotted fiber to 50 ml of simulated lung fluid ("SLF") for 6 hours. The entire test system is maintained at 37°C to simulate the temperature of the human body.

[0009] After exposure to the SLF, the fibers are recovered and analyzed for glass content using inductively coupled plasma spectroscopy. A "blank" SLF sample is also measured and used to correct for the elements present in the SLF. Once this data is obtained, the rate at which the fibers lose mass over the time interval of the study can be calculated. To measure the dissolution rate of the fibers in simulated lung fluid, approximately 0.1 g of fiber is placed in a 50 ml centrifuge tube containing simulated lung fluid preheated to 37°C. This tube is placed in a shaking incubator and agitated at 100 cycles per minute for 6 hours. After the test, the tube is centrifuged and the solution is poured into a 60 ml syringe. This solution is passed through a 0.45 μm filter to remove particulates and then tested for glass content using inductively coupled plasma spectroscopy. This test can be performed using solutions with a near-neutral pH or acidic solutions. While no specific dissolution rate criteria exist, a standard dissolution rate of 100 ng / cm is recommended. 2 Fibers having a dissolution value of greater than 100 ng / cm 3 are considered to be indicative of non-biopersistent fibers. The inorganic fibers of the present disclosure have a dissolution value of at least 100 ng / cm 3 according to the Biopersistence Test (after 6 hours) described herein. 2 -time, at least 125ng / cm 2 -time, at least 150ng / cm 2 -time, at least 175ng / cm 2 -time, or at least 200ng / cm 2 -The dissolution value at time is shown.

[0010] The composition of the simulated lung fluid is as follows: TIFF2025134910000002.tif61141

[0011] The inorganic fibers of the present disclosure are high temperature resistant, meaning that they have a service temperature of 1260°C or higher. The service temperature may be 1300°C or higher. The inorganic fibers have a melting point (i.e., solidus temperature) of less than 1400°C, between 1260°C and 1400°C, between 1300°C and 1400°C, between 1260°C and 1380°C, or between 1300°C and 1380°C.

[0012] The inorganic fibers exhibit a linear shrinkage of greater than 5%, greater than 5.5%, or greater than 6% when exposed to temperatures of 1400°C or greater for 24 hours. The inorganic fibers exhibit a linear shrinkage of less than 4%, less than 3.5%, or less than 3% when exposed to temperatures of 1260°C or greater for 24 hours. The inorganic fibers exhibit a linear shrinkage of less than 10% when exposed to temperatures of 1300°C or greater for 24 hours.

[0013] Fibers are tested for linear shrinkage by forming them into a mat and needle-punching the mat into a pad with a density of about 4 to 10 pounds per cubic foot and a thickness of about 1 inch. Such a pad is cut into 3-inch by 5-inch pieces, and platinum pins are inserted into the surface of the material. The spacing between these pins is carefully measured and recorded. The pad is then placed in an oven, subjected to a temperature gradient, and held at that temperature for a specified period of time. After heating, the pin spacing is again measured to determine the linear shrinkage experienced by the pad. If the fibers are available in blanket form, measurements can be made directly on the blanket without the need to form a pad.

[0014] The inorganic fibers of the present disclosure include silica, magnesia, and calcia, and optionally include alumina, alkali oxides, or other additives. The inorganic fiber composition is adjusted to balance thermal performance, biopersistence, melting, and fiberization energy efficiency with product quality. The content of each component of the inorganic fiber is described in detail below. The inorganic fiber includes any logical combination of the content ranges disclosed herein (i.e., any combination not exceeding 100% by weight). Due to the optional inclusion of additives, the total of the above components may be less than 100% by weight.

[0015] The inorganic fibers comprise silica in an amount ranging from 72 to 77.3 wt%, 72 to 76 wt%, 72 to 75.5 wt%, 72 to 75.7 wt%, 72 to 76.7 wt%, 72 to 76.8 wt%, 72 to 77.3 wt%, 73 to 77.3 wt%, 72 to 75.8 wt%, 73 to 75.8 wt%, 73 to 75.5 wt%, 73.5 to 76 wt%, 74 to 76 wt%, 73.5 to 75.3 wt%, 74 to 74.8 wt%, 74.3 to 74.5 wt%, 74.4 wt%, or any logical combination of the foregoing upper and lower limits.

[0016] The inorganic fibers comprise magnesia in an amount greater than 10-15 wt%, greater than 10-14 wt%, greater than 10-13 wt%, greater than 10-12 wt%, 10.2-15 wt%, 10.5-15 wt%, 11-15 wt%, 10.2-14 wt%, 10.5-14 wt%, 11-14 wt%, 10.6-11.4 wt%, 10.8-11.3 wt%, 10.9-11.1 wt%, 11 wt%, or any logical combination of the foregoing upper and lower limits.

[0017] The inorganic fibers contain calcia in an amount of 12.5-17 wt%, 12.5-16 wt%, 12.8-17 wt%, 12.9-17 wt%, 13-17 wt%, 13-16 wt%, 13-15 wt%, 13-14 wt%, 13.2-13.8 wt%, 13.3-13.5 wt%, 13.4 wt%, or any logical combination of the foregoing upper and lower limits.

[0018] The inorganic fibers comprise alumina in an amount of 0-1.5 wt%, 0.1-1.3 wt%, 0.1-1.0 wt%, 0.3-1.3 wt%, 0.4-1.2 wt%, 0.5-1.1 wt%, 0.7-0.9 wt%, 0.8 wt%, or any logical combination of the foregoing upper and lower limits.

[0019] The inorganic fibers comprise alkali oxide in an amount of 0-0.6 wt%, 0-0.5 wt%, 0-0.4 wt%, 0-0.3 wt%, 0.1-0.6 wt%, 0.2-0.6 wt%, 0.3-0.5 wt%, 0.4 wt%, or any logical combination of the foregoing upper and lower limits.

[0020] The inorganic fibers comprise lithium oxide in an amount of 0-0.6 wt%, 0-0.5 wt%, 0-0.4 wt%, 0-0.3 wt%, 0.1-0.6 wt%, 0.2-0.6 wt%, 0-0.2 wt%, 0.1 wt%, or any logical combination of the foregoing upper and lower limits.

[0021] The inorganic fibers include potassium oxide in an amount of 0-0.6 wt%, 0-0.5 wt%, 0-0.4 wt%, 0-0.3 wt%, 0.1-0.6 wt%, 0.2-0.6 wt%, 0.2-0.4 wt%, 0.3 wt%, or any logical combination of the foregoing upper and lower limits.

[0022] The inorganic fibers contain potassium oxide in an amount of 70 mol % or less based on the total content of alkali metal oxides in the inorganic fibers.

[0023] The inorganic fibers include additives such as zirconia, boron trioxide, phosphorus pentoxide, iron oxide, strontia, or combinations thereof. The inorganic fibers exclude one or more of zirconia, boron trioxide, phosphorus pentoxide, iron oxide, and / or strontia. Any one additive is present in an amount less than 0.1 wt.% or less than 0.05 wt.%.

[0024] The inorganic fibers contain iron oxide in an amount of less than 0.15%, 0.10%, 0.10%, or 0.07% by weight. The inorganic fibers contain sodia in an amount of less than 0.10%, 0.08%, 0.06%, or 0.05% by weight. The inorganic fibers contain other impurities, each present in an amount of less than 0.3%, 0.20%, 0.15%, 0.10%, 0.05%, or 0.01% by weight. The fibers contain a total impurity amount of less than 1.0%, 0.75%, 0.50%, 0.30%, or 0.10% by weight.

[0025] As mentioned above, the inorganic fibers of the present disclosure include silica, magnesia, calcia, alumina, alkali oxides, and additives in any combination within the aforementioned content ranges. The following specific combinations are for illustrative purposes and are not intended to be limiting. The inorganic fibers include: 72-77.3 wt.% silica, 10.2-15 wt.% magnesia, 12.5-17 wt.% calcia, 0-1.5 wt.% alumina, and 0-0.6 wt.% total alkali oxides; 72 to 76.5 wt. % silica, 11 to 15 wt. % magnesia, 12.5 to 17 wt. % calcia, 0 to 1.5 wt. % alumina, and 0 to 0.6 wt. % total alkali oxides; 72-76 wt. % silica, 11-15 wt. % magnesia, 13-17 wt. % calcia, 0-1.5 wt. % alumina, and 0-0.6 wt. % total alkali oxides; 72-76.8 wt.% silica, 10.2-15 wt.% magnesia, 13-17 wt.% calcia, 0-1.5 wt.% alumina, and 0-0.6 wt.% total alkali oxides; 72-75.8 wt.% silica, 11-15 wt.% magnesia, 13-17 wt.% calcia, 0.2-1.5 wt.% alumina, and 0-0.6 wt.% total alkali oxides; 72 to 77.1 wt. % silica, 10.2 to 15 wt. % magnesia, 12.5 to 17 wt. % calcia, 0.2 to 1.5 wt. % alumina, and 0 to 0.6 wt. % total alkali oxides; 72 to 77.1 wt. % silica, 10.2 to 15 wt. % magnesia, 12.5 to 17 wt. % calcia, 0 to 1.5 wt. % alumina, and 0.2 to 0.6 wt. % total alkali oxides; 72 to 75.7 wt. % silica, 11 to 15 wt. % magnesia, 13 to 17 wt. % calcia, 0.2 to 1.5 wt. % alumina, and 0.1 to 0.6 wt. % total alkali oxides; 72 to 76.7 wt. % silica, 10.5 to 15 wt. % magnesia, 12.8 to 17 wt. % calcia, 0 to 1.5 wt. % alumina, and 0 to 0.6 wt. % total alkali oxides; 72-76 wt. % silica, 11-15 wt. % magnesia, 12.5-17 wt. % calcia, 0-1.5 wt. % alumina, and 0-0.6 wt. % total alkali oxides; 72-76 wt. % silica, 10.2-15 wt. % magnesia, 13-17 wt. % calcia, 0-1.5 wt. % alumina, and 0-0.6 wt. % total alkali oxides; the sum of 73 to 75.5 wt. % silica, 10.5 to 11.5 wt. % magnesia, 13 to 14 wt. % calcia, 0.3 to 1 wt. % alumina, and 0.2 to 0.6 wt. % total alkali oxides; 73.3 to 75.2 wt. % silica, 10.5 to 11.5 wt. % magnesia, 12.9 to 13.9 wt. % calcia, 0.8 wt. % alumina, 0.1 wt. % lithium oxide, and 0.3 wt. % potassium oxide; 73 to 74.8 wt. % silica, 11.1 to 12.1 wt. % magnesia, 12.7 to 13.7 wt. % calcia, 0.8 wt. % alumina, 0.1 wt. % lithium oxide, and 0.3 wt. % potassium oxide; 73 to 74.8 wt. % silica, 11.5 to 12.5 wt. % magnesia, 12.3 to 13.3 wt. % calcia, 0.8 wt. % alumina, 0.1 wt. % lithium oxide, and 0.3 wt. % potassium oxide; 73-74.8 wt.% silica, 12-13 wt.% magnesia, 11.8-12.8 wt.% calcia, 0.8 wt.% alumina, 0.1 wt.% lithium oxide, and 0.3 wt.% potassium oxide; 74.4 wt.% silica, 11 wt.% magnesia, 13.4 wt.% calcia, 0.8 wt.% alumina, 0.1 wt.% lithium oxide, and 0.3 wt.% potassium oxide; 74.2 wt.% silica, 11.6 wt.% magnesia, 13.0 wt.% calcia, 0.8 wt.% alumina, 0.1 wt.% lithium oxide, and 0.3 wt.% potassium oxide; 74% by weight silica, 11.6% by weight magnesia, 13.2% by weight calcia, 0.8% by weight alumina, 0.1% by weight lithium oxide, and 0.3% by weight potassium oxide; 74% by weight silica, 12% by weight magnesia, 12.8% by weight calcia, 0.8% by weight alumina, 0.1% by weight lithium oxide, and 0.3% by weight potassium oxide, or 74 wt% silica, 12.5 wt% magnesia, 12.3 wt% calcia, 0.8 wt% alumina, 0.1 wt% lithium oxide, and 0.3 wt% potassium oxide. [Example]

[0026] Fibers of various compositions were prepared and tested for thermal performance, as described in detail below. The compositions of Comparative Examples C2-C9 and Examples 1-18c are summarized below in Table 1. Comparative Example C1 contained alumina silicate fibers. TIFF2025134910000003.tif153141TIFF2025134910000004.tif196141

[0027] Figure 1 compares the temperature-dependent viscosity curves of a magnesia-silica melt with an excessively high silica content of 79.2 wt% (Comparative Example C4, shown by the dashed line on the right side of the graph), a calcia-magnesia-silica melt with an excessively high silica content of 78.9 wt% (Comparative Example C6, shown by the square in the center of the graph), and a calcia-magnesia-silica melt with a low silica content of 74 wt% (Example 2, shown by the triangle on the left side of the graph). As shown in Figure 1, the viscosity curve shifts to a lower temperature as the silica content decreases and as calcia is replaced by magnesia. The temperatures at which the viscosity point reaches 50 poise are 1561°C, 1737°C, and 1815°C for Example 2, Comparative Example C6, and Comparative Example C4, respectively. By shifting the temperature-viscosity curve approximately 250°C lower, the melting and fiberization processes can be carried out at lower temperatures, which is expected to reduce energy consumption, improve melting and production rates, and extend the life of furnaces, electrodes, and fiberization equipment. Furthermore, by shifting the viscosity curve to a lower temperature and flattening the slope of the curve, the fiberization temperature range of the melt is expanded, improving the quality of the fiber product, such as the fiber index and blanket tensile strength. Therefore, it is important to keep the silica content of the inorganic fiber to 77.3% by weight or less.

[0028] Furthermore, to achieve the desired thermal performance, the silica content should be at least 72 wt. %, or even as low as 73 wt. Thermal performance refers to the linear shrinkage and compression recovery of the textile after exposure to the applied temperature. As seen in Comparative Examples C7 and C8, low silica (e.g., less than 73 or 71.5 wt. %) resulted in a linear shrinkage of more than 10% after 24 hours of baking at 1260°C, as shown in Table 2. Meanwhile, materials with silica contents within the range disclosed herein (e.g., 72 wt. % or greater) exhibited much improved thermal stability, e.g., a linear shrinkage of less than 4% after 24 hours of baking at 1260°C. Further results regarding thermal performance, i.e., linear shrinkage, compression recovery, and compressive strength, are shown in Tables 2–4, respectively.

[0029] The method for testing the linear shrinkage rate is as described above.

[0030] Compression recovery is an indicator of the mechanical performance of inorganic fibers when the fibers are exposed to a desired use temperature for a specified period of time. Compression recovery was measured by baking test pads made from inorganic fiber materials at a test temperature for a selected period of time. The baked test pads were then compressed to half their original thickness and allowed to stand for 24 hours to rebound. The amount of rebound was measured as the percentage of the pad's compressed thickness that recovered.

[0031] Compressive strength was measured by baking test pads made from inorganic fibrous materials at a test temperature for a selected time, and then applying a compressive force at a rate of 1 inch per minute until the baked test pad was compressed to 50% of its original thickness.

[0032] In Tables 2-6 below, a dash indicates that a measurement was not made or was not possible to measure. TIFF2025134910000005.tif169141TIFF2025134910000006.tif157141TIFF2025134910000007.tif45141TIFF2025134910000008.tif18414 1TIFF2025134910000009.tif93141TIFF2025134910000010.tif92141TIFF2025134910000011.tif183141TIFF2025134910000012.tif39141

[0033] Fibers with excessively high silica contents (e.g., greater than 75.8 or 77.5 wt.%), such as Comparative Example C6, had excellent thermal performance (low linear shrinkage) even at temperatures as high as 1300°C. However, these high-silica fibers exhibited significantly elevated liquidus temperatures as well as melting points. Figure 2 shows the dependence of liquidus temperature on silica content in the fiber. As the silica content in the fiber increased, the liquidus temperature increased from 1500°C to 1800°C. The liquidus temperatures and liquidus viscosities of the comparative examples and examples are shown in Table 5 below. TIFF2025134910000013.tif142141

[0034] As can be seen, the inorganic fibers of the present disclosure are fibers with low biopersistence. This is confirmed in Table 6 below, which shows dissolution rates tested for various time periods under static and flow-through conditions. The flow-through test measures the rate of mass loss (ng / cm2·hr) from the fiber under conditions simulating the temperature and chemical conditions found in the human lung. As mentioned above, this test involves exposing approximately 0.1 g of de-shotted fiber to a flow of simulated lung fluid (SLF) at 0.3 mL / min. The entire test system is maintained at 37°C to simulate the temperature of the human body. Testing is preferably performed for up to four weeks. After the SLF passes through the fiber, it is collected and analyzed for glass content using inductively coupled plasma spectroscopy. A "blank" SLF sample is also measured and used to correct for elements present in the SLF. Once this data is obtained, the rate at which the fiber loses mass over the time interval of this study can be calculated. As mentioned above, a 100 ng / cm2 SLF is used to calculate the rate at which the fiber loses mass. 2 Fibers with dissolution values ​​greater than -10 hours are considered to be indicative of non-biopersistent fibers. TIFF2025134910000014.tif146141TIFF2025134910000015.tif46141

[0035] The following statements are used to support this disclosure:

[0036] 1. High temperature resistant inorganic fibers comprising a lower limit of 72% by weight silica and an upper limit of 74% by weight, or 74.4% by weight, or 75% by weight, or 75.5% by weight, or 75.7% by weight, or 75.8% by weight, or 76% by weight, or 76.3% by weight, or 76.7% by weight, or 76.8% by weight, or 77% by weight, or 77.3% by weight silica; or a lower limit of 73% by weight silica and an upper limit of 74%, or 74.4%, or 75%, or 75.5%, or 75.7%, or 75.8%, or 76%, or 76.3%, or 76.7%, or 76.8%, or 77%, or 77.3% by weight silica; or a lower limit of 73.3% by weight silica and an upper limit of 74%, or 74.4%, or 75%, or 75.5%, or 75.7%, or 75.8%, or 76%, or 76.3%, or 76.7%, or 76.8%, or 77%, or 77.3% by weight silica; or a lower limit of 73.7% by weight silica and an upper limit of 74%, or 74.4%, or 75%, or 75.5%, or 75.7%, or 75.8%, or 76%, or 76.3%, or 76.7%, or 76.8%, or 77%, or 77.3% by weight silica; or a lower limit of 74% by weight silica and an upper limit of 74.4%, or 75%, or 75.5%, or 75.7%, or 75.8%, or 76%, or 76.3%, or 76.7%, or 76.8%, or 77%, or 77.3% by weight silica; or a lower limit of 74.4% by weight of silica and an upper limit of 75%, or 75.5%, or 75.7%, or 75.8%, or 76%, or 76.3%, or 76.7%, or 76.8%, or 77%, or 77.3% by weight of silica; The inorganic fibers contain 10 to 15 wt. % magnesia, 12.5 to 17 wt. % calcia, 0 to 1.5 wt. % alumina, and 0 to 0.6 wt. % total alkali oxides; The inorganic fibers have a use temperature of at least 1260°C, and The inorganic fibers exhibit a shrinkage rate of greater than 5% after exposure to a temperature of 1400°C for 24 hours.

[0037] 2.1 Inorganic fibers according to claim 1, comprising a lower limit of 10% by weight of magnesia and an upper limit of 11% by weight, or 11.1% by weight, or 11.2% by weight, or 11.3% by weight, or 11.4% by weight, or 11.7% by weight, or 12% by weight, or 12.3% by weight, or 12.7% by weight, or 13% by weight, or 13.5% by weight, or 14% by weight, or 14.5% by weight, or 15% by weight of magnesia; a lower limit of 10.3% by weight of magnesia and an upper limit of 11%, or 11.1%, or 11.2%, or 11.3%, or 11.4%, or 11.7%, or 12%, or 12.3%, or 12.7%, or 13%, or 13.5%, or 14%, or 14.5%, or 15% by weight of magnesia; or a lower limit of 10.5% by weight of magnesia and an upper limit of 11%, or 11.1%, or 11.2%, or 11.3%, or 11.4%, or 11.7%, or 12%, or 12.3%, or 12.7%, or 13%, or 13.5%, or 14%, or 14.5%, or 15% by weight of magnesia; or a lower limit of 10.6% by weight of magnesia and an upper limit of 11%, or 11.1%, or 11.2%, or 11.3%, or 11.4%, or 11.7%, or 12%, or 12.3%, or 12.7%, or 13%, or 13.5%, or 14%, or 14.5%, or 15% by weight of magnesia; or a lower limit of 10.8% by weight of magnesia and an upper limit of 11%, or 11.1%, or 11.2%, or 11.3%, or 11.4%, or 11.7%, or 12%, or 12.3%, or 12.7%, or 13%, or 13.5%, or 14%, or 14.5%, or 15% by weight of magnesia; or a lower limit of 10.9% by weight of magnesia and an upper limit of 11%, or 11.1%, or 11.2%, or 11.3%, or 11.4%, or 11.7%, or 12%, or 12.3%, or 12.7%, or 13%, or 13.5%, or 14%, or 14.5%, or 15% by weight of magnesia; or or comprising a lower limit of 11% by weight of magnesia and an upper limit of 11.1%, or 11.2%, or 11.3%, or 11.4%, or 11.7%, or 12%, or 12.3%, or 12.7%, or 13%, or 13.5%, or 14%, or 14.5%, or 15% by weight of magnesia; Inorganic fibers comprising a lower limit of 11.5% by weight of magnesia and an upper limit of 11.7%, or 12%, or 12.3%, or 12.7%, or 13%, or 13.5%, or 14%, or 14.5%, or 15% by weight of magnesia.

[0038] 3. Inorganic fibers according to 1 or 2, the calcia content is 12.4% by weight at the lower end and 12.5% ​​by weight, or 13.4% by weight, or 13.5% by weight, or 13.8% by weight, or 14% by weight, or 14.5% by weight, or 15% by weight, or 15.5% by weight, or 16% by weight, or 16.5% by weight, or 17% by weight at the upper end; or or comprising a lower limit of 12.5% ​​by weight of calcia and an upper limit of 13.4%, or 13.5%, or 13.8%, or 14%, or 14.5%, or 15%, or 15.5%, or 16%, or 16.5%, or 17% by weight of calcia; or comprising a lower limit of 12.6% by weight of calcia and an upper limit of 13.4%, or 13.5%, or 13.8%, or 14%, or 14.5%, or 15%, or 15.5%, or 16%, or 16.5%, or 17% by weight of calcia; or comprising a lower limit of 12.7% by weight of calcia and an upper limit of 13.4%, or 13.5%, or 13.8%, or 14%, or 14.5%, or 15%, or 15.5%, or 16%, or 16.5%, or 17% by weight of calcia; or comprising a lower limit of 12.8% by weight of calcia and an upper limit of 13.4%, or 13.5%, or 13.8%, or 14%, or 14.5%, or 15%, or 15.5%, or 16%, or 16.5%, or 17% by weight of calcia; or comprising a lower limit of 13% by weight of calcia and an upper limit of 13.4%, or 13.5%, or 13.8%, or 14%, or 14.5%, or 15%, or 15.5%, or 16%, or 16.5%, or 17% by weight of calcia; or comprising a lower limit of 13.3% by weight of calcia and an upper limit of 13.4%, or 13.5%, or 13.8%, or 14%, or 14.5%, or 15%, or 15.5%, or 16%, or 16.5%, or 17% by weight of calcia; or comprising a lower limit of 13.4% by weight of calcia and an upper limit of 13.5%, or 13.8%, or 14%, or 14.5%, or 15%, or 15.5%, or 16%, or 16.5%, or 17% by weight of calcia; Inorganic fibers comprising a lower limit of 13.5% by weight of calcia and an upper limit of 13.8% by weight, or 14% by weight, or 14.5% by weight, or 15% by weight, or 15.5% by weight, or 16% by weight, or 16.5% by weight, or 17% by weight of calcia.

[0039] 4. Inorganic fibers according to any one of 1 to 3, comprising a lower limit of 0% by weight of alumina and an upper limit of 0.8% by weight, or 0.9% by weight, or 1% by weight, or 1.1% by weight, or 1.2% by weight, or 1.3% by weight, or 1.4% by weight, or 1.5% by weight of alumina; or a lower limit of 0.1 wt.% alumina and an upper limit of 0.8 wt.%, or 0.9 wt.%, or 1 wt.%, or 1.1 wt.%, or 1.2 wt.%, or 1.3 wt.%, or 1.4 wt.%, or 1.5 wt.% alumina; or a lower limit of 0.2 wt.% alumina and an upper limit of 0.8 wt.%, or 0.9 wt.%, or 1 wt.%, or 1.1 wt.%, or 1.2 wt.%, or 1.3 wt.%, or 1.4 wt.%, or 1.5 wt.% alumina; or a lower limit of 0.3 wt.% alumina and an upper limit of 0.8 wt.%, or 0.9 wt.%, or 1 wt.%, or 1.1 wt.%, or 1.2 wt.%, or 1.3 wt.%, or 1.4 wt.%, or 1.5 wt.% alumina; or a lower limit of 0.4 wt.% alumina and an upper limit of 0.8 wt.%, or 0.9 wt.%, or 1 wt.%, or 1.1 wt.%, or 1.2 wt.%, or 1.3 wt.%, or 1.4 wt.%, or 1.5 wt.% alumina; or a lower limit of 0.5 wt.% alumina and an upper limit of 0.8 wt.%, or 0.9 wt.%, or 1 wt.%, or 1.1 wt.%, or 1.2 wt.%, or 1.3 wt.%, or 1.4 wt.%, or 1.5 wt.% alumina; or a lower limit of 0.6 wt.% alumina and an upper limit of 0.8 wt.%, or 0.9 wt.%, or 1 wt.%, or 1.1 wt.%, or 1.2 wt.%, or 1.3 wt.%, or 1.4 wt.%, or 1.5 wt.% alumina; or a lower limit of 0.7 wt.% alumina and an upper limit of 0.8 wt.%, or 0.9 wt.%, or 1 wt.%, or 1.1 wt.%, or 1.2 wt.%, or 1.3 wt.%, or 1.4 wt.%, or 1.5 wt.% alumina; or Inorganic fibers comprising a lower limit of 0.8 wt. % alumina and an upper limit of 0.9 wt. %, or 1 wt. %, or 1.1 wt. %, or 1.2 wt. %, or 1.3 wt. %, or 1.4 wt. %, or 1.5 wt. % alumina.

[0040] 5. Inorganic fibers according to any one of 1 to 4, comprising a lower limit of 0 wt. % total alkali oxides and an upper limit of 0.4 wt. %, or 0.5 wt. %, or 0.6 wt. % total alkali oxides; or a lower limit of 0.1 wt. % total alkali oxides and an upper limit of 0.4 wt. %, or 0.5 wt. %, or 0.6 wt. % total alkali oxides; or a lower limit of 0.2 wt. % total alkali oxides and an upper limit of 0.4 wt. %, or 0.5 wt. %, or 0.6 wt. % total alkali oxides; or Inorganic fibers comprising a lower limit of 0.3 wt. % total alkali oxides and an upper limit of 0.4 wt. %, or 0.5 wt. %, or 0.6 wt. % total alkali oxides.

[0041] 6. Inorganic fibers according to any one of 1 to 5, containing lithium oxide with a lower limit of 0% by weight and lithium oxide with an upper limit of 0.2% by weight, or 0.3% by weight, or 0.4% by weight, or 0.5% by weight, or 0.6% by weight, or a lower limit of 0.1 wt. % lithium oxide and an upper limit of 0.2 wt. %, or 0.3 wt. %, or 0.4 wt. %, or 0.5 wt. %, or 0.6 wt. % lithium oxide; or Inorganic fibers comprising a lower limit of 0.2 wt. % lithium oxide and an upper limit of 0.3 wt. %, or 0.4 wt. %, or 0.5 wt. %, or 0.6 wt. % lithium oxide.

[0042] 7. Inorganic fibers according to any one of 1 to 6, containing potassium oxide with a lower limit of 0% by weight and potassium oxide with an upper limit of 0.2% by weight, or 0.3% by weight, or 0.4% by weight, or 0.5% by weight, or 0.6% by weight, or or comprising a lower limit of 0.1 wt. % potassium oxide and an upper limit of 0.2 wt. %, or 0.3 wt. %, or 0.4 wt. %, or 0.5 wt. %, or 0.6 wt. % potassium oxide; or comprising a lower limit of 0.2% by weight of potassium oxide and an upper limit of 0.3%, or 0.4%, or 0.5%, or 0.6% by weight of potassium oxide; Inorganic fibers comprising a lower limit of 0.3% by weight of potassium oxide and an upper limit of 0.4%, 0.5%, or 0.6% by weight of potassium oxide.

[0043] 8. The inorganic fiber according to any one of 1 to 7, which contains potassium oxide in an amount of 70 mol % or less based on the total content of alkali metal oxides in the inorganic fiber.

[0044] 9. The inorganic fibers according to any one of 1 to 8, comprising zirconia, boron trioxide, phosphorus pentoxide, iron oxide, strontia, or a combination thereof.

[0045] 10. The inorganic fibers according to any one of 1 to 9, excluding zirconia, boron trioxide, phosphorus pentoxide, iron oxide, strontia, or a combination thereof.

[0046] 11. The inorganic fiber according to any one of 1 to 10, comprising an additive selected from zirconia, boron trioxide, phosphorus pentoxide, iron oxide, strontia, and combinations thereof in an amount of less than 0.1 wt % or less than 0.05 wt %.

[0047] 12. Inorganic fibers according to any one of 1 to 11, wherein the inorganic fibers have a use temperature of at least 1260°C, or at least 1280°C, or at least 1300°C, at least 1320°C, at least 1340°C, at most 1380°C, or at most 1400°C.

[0048] 13. The inorganic fiber according to any one of 1 to 12, wherein the inorganic fiber has a melting point of less than 1400°C, or from 1260°C to less than 1400°C, or from 1300°C to less than 1400°C, or from 1260°C to 1380°C, or from 1300°C to 1380°C.

[0049] 14. The inorganic fiber according to any one of 1 to 13, wherein the inorganic fiber exhibits a linear shrinkage of greater than 5% after exposure to a temperature of 1400°C for 24 hours, or a linear shrinkage of greater than 5.5% after exposure to a temperature of 1400°C for 24 hours, or a linear shrinkage of greater than 6% after exposure to a temperature of 1400°C for 24 hours, or a linear shrinkage of less than 4% after exposure to a temperature of 1260°C for 24 hours, or a linear shrinkage of less than 3.5% after exposure to a temperature of 1260°C for 24 hours, or a linear shrinkage of less than 3% after exposure to a temperature of 1260°C for 24 hours, or a linear shrinkage of less than 10% after exposure to a temperature of 1300°C or higher for 24 hours.

[0050] 15. The inorganic fiber according to any one of 1 to 14, comprising a weight percent ratio of potassium oxide to lithium oxide of less than 7, or less than 6.5, or less than 6, or less than 5.5, or less than 5, or less than 4.5, or less than 4, or less than 3.5, or less than 3, or less than 2.5, or less than 2.

[0051] 16. Inorganic fibers according to any one of 1 to 15, comprising a sum of lithium oxide and potassium oxide greater than 0.2 and less than 0.25, or less than 0.3, or less than 0.35, or less than 0.4, or less than 0.45, or less than 0.5; or Contains lithium oxide and potassium oxide in a ratio greater than 0.25 and less than 0.3, or less than 0.35, or less than 0.4, or less than 0.45, or less than 0.5; or Contains lithium oxide and potassium oxide in an amount greater than 0.3 and less than 0.35, or less than 0.4, or less than 0.45, or less than 0.5; or Contains lithium oxide and potassium oxide in a sum greater than 0.35 and less than 0.4, or less than 0.45, or less than 0.5; or Inorganic fibers containing lithium oxide and potassium oxide in total greater than 0.4 and less than 0.45 or less than 0.5.

[0052] Although the present disclosure has been described with reference to embodiments and optional features, modifications and variations of the embodiments disclosed herein may be anticipated by those skilled in the art, and such modifications and variations are deemed to be within the scope of the present disclosure. It should also be understood that the above description is intended to be illustrative and not restrictive. Many alternative embodiments will be apparent to those skilled in the art upon reviewing the above description. Furthermore, the terms and expressions employed herein are used as terms of description, not of limitation, and the use of such terms and expressions is not intended to exclude future equivalents or portions thereof shown and described, but rather recognizes that various modifications are possible within the scope of the present disclosure.

Claims

1. A high temperature resistant inorganic fiber, 72 to 77.3 wt. % silica; 10.5 to 15 wt. % magnesia; 12.4 to 17 wt. % calcia; 0 to 1.5 wt. % alumina, and 0 to 0.6 wt. % total alkali oxides; Including, The fibers have a use temperature of at least 1260°C; and A high temperature resistant inorganic fiber, wherein the fiber exhibits a shrinkage rate of greater than 5% after exposure to a temperature of 1400°C for 24 hours.

2. 10. The fiber of claim 1, wherein the fiber comprises 11 to 15 weight percent magnesia and 13 to 17 weight percent calcia.

3. 10. The fiber of claim 1, wherein the fiber has a pulmonary function of 100 ng / cm after 6 hours in simulated lung fluid. ２ - Fibers that exhibit a greater dissolution rate than

4. 10. The fiber of claim 1, wherein the fiber contains less than 0.1% by weight of strontia.

5. 10. The fiber of claim 1, wherein said fiber is free of strontia.

6. 10. The fiber of claim 1, wherein the fiber comprises greater than 0-0.5 weight percent lithium oxide.

7. 10. The fiber of claim 1, wherein the fiber comprises greater than 0-0.5% by weight potassium oxide.

8. The fiber of claim 1, wherein the fiber comprises 0.5 to 1.1 weight percent alumina.

9. 10. The fiber of claim 1, wherein the fiber comprises: 73 to 75.8 wt. % silica; 11 to 15 wt. % magnesia; 13 to 17% by weight of calcia; 0.2 to 1.5 wt. % alumina, and 0 to 0.6 wt. % total alkali oxides; Including, fiber.

10. 10. The fiber of claim 1, wherein the fiber comprises potassium oxide and lithium oxide, and the weight ratio of potassium oxide to lithium oxide is less than 7.

11. 2. The fiber of claim 1, wherein the fiber comprises potassium oxide and lithium oxide, and the sum of the potassium oxide and lithium oxide is greater than 0.2% and less than 0.5% by weight.

12. An inorganic fiber, 72 to 77.3 wt. % silica; 10.2 to 15 wt. % magnesia; 12.5 to 17% by weight of calcia; 0 to 1.5 wt. % alumina, and 0 to 0.6 wt. % total alkali oxides; Including, The fibers have a use temperature of at least 1260°C; and The fibers are inorganic fibers having a melting point of less than 1400°C.

13. 13. The fiber of claim 12, comprising 73.9 to 74.8 wt. % silica, 10.5 to 11.5 wt. % magnesia, 13.0 to 13.8 wt. % calcia, 0.6 to 1.0 wt. % alumina, 0.05 to 0.15 wt. % lithium oxide, and 0.2 to 0.4 wt. % potassium oxide.

14. 13. The fiber of claim 12, comprising 73-75.8% by weight of silica, 10.5-15% by weight of magnesia, 12.4-17% by weight of calcia, 0.1-1.5% by weight of alumina, maximum 0.5% by weight of lithium oxide, maximum 0.5% by weight of potassium oxide, less than 0.15% by weight of iron oxide, less than 0.1% by weight of sodium, and incidental impurities, each of said impurities constituting less than 0.2% by weight.

15. 15. The fiber of claim 14, wherein the sum of the potassium oxide and lithium oxide is greater than 0.2% and less than 0.5% by weight, and the weight ratio of potassium oxide to lithium oxide is less than 7.

16. 13. The fiber of claim 12, wherein the fiber comprises potassium oxide and lithium oxide, and the weight ratio of potassium oxide to lithium oxide is less than 7.

17. 13. The fiber of claim 12, wherein the fiber comprises potassium oxide and lithium oxide, and the sum of the potassium oxide and lithium oxide is greater than 0.2% and less than 0.5% by weight.

18. A method for producing inorganic fibers, comprising: preparing a mixture comprising 72-77.3 wt. % silica, 10.2-15 wt. % magnesia, 12.5-17 wt. % calcia, 0-1.5 wt. % alumina, and 0-0.6 wt. % total alkali oxides; melting the mixture at a temperature less than 1400°C to form a melt; and forming the inorganic fibers by fiberizing the molten material; Including, The method wherein the inorganic fibers have a use temperature of at least 1260°C.

19. 20. The method of claim 18, wherein the mixture comprises potassium oxide and lithium oxide, and the weight ratio of potassium oxide to lithium oxide is less than 7.

20. 20. The method of claim 18, wherein the mixture comprises potassium oxide and lithium oxide, and the sum of the potassium oxide and lithium oxide is greater than 0.2 wt. % and less than 0.5 wt. %.

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