Multiphase microcrystalline glass fiber and preparation method thereof

Abstract

The invention provides a multiphase microcrystal glass fiber and a preparation method thereof, and the preparation method comprises the following steps: (1) placing mixed glass powder in a kiln, and sequentially melting, homogenizing and clarifying to obtain mixed glass liquid; wherein the mixed glass powder comprises SiO2 (silicon dioxide), Al2O3 (aluminum oxide), Li2O (lithium oxide), P2O5 (phosphorus pentoxide), ZrO2 (zirconium oxide), MgO (magnesium oxide), CaO (calcium oxide), TiO2 (titanium oxide), Na2O (sodium oxide), K2O (potassium oxide), BaO (barium oxide), ZnO ( (2) enabling the mixed glass liquid to flow out through a gradient heating furnace, and entering a heat preservation tank for devitrification to obtain microcrystalline glass liquid; wherein crystals in the glass ceramic liquid comprise at least one of lithium disilicate, lithium silicate, petalite or cordierite; and (3) enabling the microcrystalline glass liquid to flow out through a temperature control bushing plate, and drawing to obtain the multiphase microcrystalline glass fiber. According to the scheme, through cooperation of the components and the process, it is ensured that controllable devitrification of the glass is completed, meanwhile, good high-temperature fluidity is maintained, continuous preparation from molten glass to the multiphase microcrystalline glass fiber is successfully achieved, and the obtained glass fiber product has the high elastic modulus, the low dielectric constant and the low thermal expansion coefficient.

Description

Technical Field

[0001] This invention relates to the field of glass fiber preparation technology, and in particular to a multiphase microcrystalline glass fiber and its preparation method. Background Technology

[0002] Microcrystalline glass fiber, as a high-performance fiber that combines the continuous formability of glass with the high-temperature resistance, high strength, and high modulus of ceramics, has broad application prospects in high-temperature insulation and composite material reinforcement. However, the development of high-performance microcrystalline glass fiber still faces dual bottlenecks in component design and preparation processes. Existing glass composition systems often struggle to achieve synergistic control and stable precipitation of multiple functional crystalline phases, easily leading to a single main crystalline phase or disordered crystalline phase growth. This results in fibers generally exhibiting insufficient mechanical properties, high dielectric constant, and high coefficient of thermal expansion, failing to meet the comprehensive requirements of high-performance composite materials for low dielectric constant, low expansion, and high strength.

[0003] The limitations of the aforementioned component design further exacerbate the contradiction between fiber formation and crystallization during the preparation process. Current research mostly employs the sol-gel method combined with electrospinning to prepare microcrystalline glass fibers. However, this method suffers from low production capacity and poor stability, and the organic matter in the precursor easily induces voids and cracks within the fiber after heat treatment, severely impairing mechanical properties. Although the melt method has advantages such as mature technology, high efficiency, and suitability for large-scale production, it is still difficult to coordinate the relationship between the high-temperature drawing process and the controllable crystallization of the multicrystalline phases during subsequent heat treatment when preparing multiphase microcrystalline glass fibers, thus restricting the reliable preparation of high-performance multiphase microcrystalline glass fibers.

[0004] Therefore, there is an urgent need to provide a multiphase microcrystalline glass fiber and its preparation method. Summary of the Invention

[0005] This invention provides a multiphase microcrystalline glass fiber and its preparation method, which can solve the problems of difficulty in controlling the crystal phase and fiber-forming properties during the microcrystalline glass fiber process, and the low mechanical properties, high dielectric properties and high expansion index of the prepared glass fiber.

[0006] In a first aspect, the present invention provides a method for preparing multiphase microcrystalline glass fibers, the method comprising the following steps: (1) The mixed glass powder is placed in a kiln and successively melted and homogenized to obtain a mixed glass liquid; wherein the mixed glass powder includes SiO2, Al2O3, Li2O, P2O5, ZrO2, MgO, CaO, TiO2, Na2O, K2O, BaO, ZnO, Sb2O3, and Y2O3; (2) The mixed glass liquid is flowed out through a gradient heating furnace and enters a heat preservation tank for crystallization to obtain microcrystalline glass liquid; wherein the crystals in the microcrystalline glass liquid include at least one of lithium disilicate, lithium silicate, lithium feldspar or cordierite; (3) The microcrystalline glass liquid is drawn into fibers after flowing out through a temperature-controlled baffle plate to obtain the multiphase microcrystalline glass fiber.

[0007] Preferably, in step (1), the mixed glass powder comprises, by mass percentage, 50-75% SiO2, 1-12% Al2O3, 2-11% Li2O, 0-6% MgO, 0-4% CaO, 0-4% TiO2, 0.1-5% Na2O, 0.1-4% K2O, 1-6% P2O5, 1-7% ZrO2, 0-3% BaO, 0-2% ZnO, 0-3% Sb2O3, and 0-2% Y2O3.

[0008] Preferably, the mass percentages of SiO2, Li2O, Sb2O3, Y2O3, Na2O, and K2O satisfy the following relationship: 70%≤SiO2+Li2O≤80%, 1%≤Sb2O3+Y2O3≤4%, 1%≤Li2O+Na2O+K2O≤15%.

[0009] Preferably, by mass percentage, the mixed glass powder comprises 62-70% SiO2, 3-10% Al2O3, 3-10% Li2O, 0-5% MgO, 0.5-2% CaO, 1-4% TiO2, 1-5% Na2O, 0.5-3% K2O, 2-6% P2O5, 2-6% ZrO2, 0-2% BaO, 0-1% ZnO, 0-2% Sb2O3, and 0-2% Y2O3.

[0010] More preferably, by mass percentage, the mixed glass powder comprises 65-70% SiO2, 5-10% Al2O3, 2-5% Li2O, 2-5% MgO, 0.5-1.5% CaO, 1-3% TiO2, 1-2% Na2O, 0.5-1.5% K2O, 3-5% P2O5, 4-6% ZrO2, 0.5-1.5% BaO, 0.1-1% ZnO, 0.5-1.5% Sb2O3, and 0-1% Y2O3.

[0011] Preferably, in step (1), the melting temperature is 1500~1700℃ and the time is 2~24h; the homogenization and clarification temperature is 1500℃~1550℃ and the time is 1~2h.

[0012] Preferably, in step (2), the average particle size of the crystals in the microcrystalline glass melt is 1~100nm and the crystallinity is 10-40%.

[0013] Preferably, in step (2), the temperature of the gradient heating furnace is 600℃~1000℃, and the temperature of the heating furnace increases in a gradient from the inlet region to the outlet region of the mixed glass liquid.

[0014] Preferably, the temperature of the heat preservation tank is 800℃~1000℃, and the heat preservation time is 1~4h.

[0015] In a second aspect, the present invention provides multiphase microcrystalline glass fibers prepared by the preparation method described in any one of the first aspects above, wherein the crystal phase of the microcrystalline glass fibers includes at least one of lithium disilicate, lithium silicate, petalite, or cordierite.

[0016] Compared with the prior art, the present invention has at least the following beneficial effects: In this invention, a precisely designed SiO2-Al2O3-Li2O-MgO basic glass system is provided, and multiple components such as CaO, TiO2, P2O5, ZrO2, Na2O, K2O, BaO, ZnO, Sb2O3, and Y2O3 are introduced in synergy to play a role in solubilization, nucleation, and clarification, thus solving the problem of polycrystalline phase equilibrium control from the source of components. In the preparation process, the mixed glass powder is first melted into a homogeneous glass liquid, which is then flowed through a gradient heating furnace. The synergistic effect of components and gradient temperature control is used to induce uniform volume nucleation of the glass body, forming a high-density crystal nucleus base. Subsequently, the glass liquid enters a heat preservation tank set in a specific crystallization temperature range. Under constant thermal environment, carefully proportioned oxides such as Li2O, Al2O3, and MgO in the components selectively grow multiple crystalline phases such as lithium disilicate, lithium silicate, litharge, and cordierite, forming a microcrystalline glass liquid. Finally, stable drawing is achieved through a temperature-controlled baffle to form multiphase microcrystalline glass fibers. By synergistically combining the above components and processes, good high-temperature fluidity was maintained while ensuring controllable crystallization of the glass. This successfully achieved continuous preparation from molten glass to multiphase microcrystalline glass fibers, resulting in glass fiber products with excellent comprehensive properties including high elastic modulus, low dielectric constant, and low coefficient of thermal expansion. Detailed Implementation

[0017] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are some embodiments of the present invention, but not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0018] This invention provides a method for preparing multiphase microcrystalline glass fibers, which includes the following steps: (1) The mixed glass powder is placed in a kiln and successively melted and homogenized to obtain a mixed glass liquid; wherein the mixed glass powder includes SiO2, Al2O3, Li2O, P2O5, ZrO2, MgO, CaO, TiO2, Na2O, K2O, BaO, ZnO, Sb2O3, and Y2O3; (2) The mixed glass liquid is flowed out through a gradient heating furnace and enters a heat preservation tank for crystallization to obtain microcrystalline glass liquid; wherein the crystals in the microcrystalline glass liquid include at least one of lithium disilicate, lithium silicate, lithium feldspar or cordierite; (3) The microcrystalline glass liquid is drawn into fibers after flowing out through a temperature-controlled baffle plate to obtain the multiphase microcrystalline glass fiber.

[0019] In this embodiment of the invention, a precisely designed SiO2-Al2O3-Li2O-MgO basic glass system is provided, and multiple components such as CaO, TiO2, P2O5, ZrO2, Na2O, K2O, BaO, ZnO, Sb2O3, and Y2O3 are introduced in synergy to play a role in solubilization, nucleation, and clarification, thus solving the problem of polycrystalline phase equilibrium control from the source of components. In the preparation process, the mixed glass powder is first melted into a homogeneous glass liquid, which is then flowed through a gradient heating furnace. The synergistic effect of components and gradient temperature control is used to induce uniform volume nucleation of the glass body, forming a high-density crystal nucleus base. Subsequently, the glass liquid enters a heat preservation tank set in a specific crystallization temperature range. Under constant thermal environment, carefully proportioned oxides such as Li2O, Al2O3, and MgO in the components selectively grow multiple crystalline phases such as lithium disilicate, lithium silicate, litharge, and cordierite, forming a microcrystalline glass liquid. Finally, stable drawing is achieved through a temperature-controlled baffle to form multiphase microcrystalline glass fibers. By synergistically combining the above components and processes, good high-temperature fluidity was maintained while ensuring controllable crystallization of the glass. This successfully achieved continuous preparation from molten glass to multiphase microcrystalline glass fibers, resulting in glass fiber products with excellent comprehensive properties including high elastic modulus, low dielectric constant, and low coefficient of thermal expansion.

[0020] According to some preferred embodiments, in step (1), the mixed glass powder comprises, by mass percentage, 50-75% SiO2 (e.g., 50%, 51%, 52%, 53%, 54%, 55%, 56%, 57%, 58%, 59%, 60%, 61%, 62%, 63%, 64%, 65%, 66%, 67%, 68%, 69%, 70%, 71%, 72%, 73%, 74%, or 75%), 1-12% Al2O3 (e.g., 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, or 12%), and 2-11% Li2O (… For example, it can be 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10% or 11%, 0-6% MgO (for example, it can be 0%, 1%, 2%, 3%, 4%, 5% or 6%), 0-4% CaO (for example, it can be 0.0%, 0.1%, 0.5%, 1.0%, 1.5%, 2.0%, 2.5%, 3.0%, 3.5% or 4.0%), 0-4% TiO2 (for example, it can be 0.0%, 0.1%, 0.5%, 1.0%, 1.5%, 2.0%, 2.5%, 3.0%, 3.5% or 4.0%), and 0.1-5% Na2O (for example, it can be 0. 1%, 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5% or 5%, 0.1% to 4% K₂O (e.g., 0.1%, 0.5%, 1.0%, 1.5%, 2.0%, 2.5%, 3.0%, 3.5% or 4.0%), 1% to 6% P₂O₅ (e.g., 1.0%, 1.5%, 2.0%, 2.5%, 3.0%, 3.5%, 4.0%, 4.5%, 5.0%, 5.5% or 6.0%), 1% to 7% ZrO₂ (e.g., 1.0%, 1.5%, 2.0%, 2.5%, 3.0%, 3.5%, 4.0%). 4.5%, 5.0%, 5.5%, 6.0%, 6.5% or 7.0%), 0-3% BaO (e.g., 0%, 0.1%, 0.5%, 1.0%, 1.5%, 2.0%, 2.5% or 3.0%), 0-2% ZnO (e.g., 0%, 0.1%, 0.5%, 1.0%, 1.5% or 2.0%), 0-3% Sb2O3 (e.g., 0%, 0.1%, 0.5%, 1.0%, 1.5%, 2.0%, 2.5% or 3.0%), 0-2% Y2O3 (e.g., 0%, 0.1%, 0.5%, 1.0%, 1.5% or 2.0%).

[0021] In this embodiment of the invention, precise design of each glass component facilitates the formation of a glass component system capable of stable wire drawing and controllable crystallization. SiO2, as a glass network forger, constitutes the basic [SiO4] tetrahedral framework; when sufficient ions are present, Al in Al2O3... 3+ [AlO4] tetrahedra can enter the glass network structure, enhancing its density, and this component is a key component in the formation of crystalline phases such as lithium feldspar. Li2O not only acts as a flux to lower the melting temperature of glass, but is also a core raw material for the formation of lithium-based crystalline phases such as lithium disilicate and lithium silicate. MgO is an essential component for the formation of cordierite crystalline phase. By precisely controlling the ratio of Li2O, Al2O3, and MgO, the proportion of main crystalline phases such as lithium disilicate, lithium feldspar, and cordierite in the final product can be effectively controlled, thereby adjusting the mechanical properties, coefficient of thermal expansion, and dielectric properties of glass fibers. P2O5, as the main nucleating agent, can produce a synergistic nucleation effect when used in combination with auxiliary nucleating agents ZrO2 and TiO2, thus providing the core driving force for high-density and uniform crystallization, and ensuring the excellent mechanical strength of the fiber. In addition, CaO, BaO, ZnO, Na2O, and K2O act as fluxes, reducing high-temperature viscosity, promoting melting and homogenization processes, and participating in regulating the thermodynamic properties of the system. Sb2O3 and Y2O3 act as clarifying agents, eliminating bubbles in the melt through high-temperature decomposition, ensuring the purity and homogeneity of the glass. Through the precise formulation and synergistic function of these components, this glass system can achieve efficient melting, stable fiber drawing, and controllable crystallization, thus facilitating the successful preparation of high-performance microcrystalline glass fibers.

[0022] According to some preferred embodiments, the mass percentages of SiO2, Li2O, Sb2O3, Y2O3, Na2O, and K2O satisfy the following relationship: 70%≤SiO2+Li2O≤80%, 1%≤Sb2O3+Y2O3≤4%, 1%≤Li2O+Na2O+K2O≤15%.

[0023] In this embodiment of the invention, by limiting the sum of the masses of SiO2 and Li2O within the aforementioned range, it is beneficial to ensure that the molten glass has a suitable viscosity at high temperatures. This satisfies the requirements for melt drawing and provides kinetic conditions for controllable crystallization in subsequent heat treatment. Furthermore, by controlling the total amounts of Li2O, Na2O, and K2O, the melting temperature can be effectively reduced without affecting the glass fiber performance. The combination of Sb2O3 and Y2O3 significantly improves the overall clarification effect, ensuring the molten glass is pure and bubble-free. Thus, through the synergistic control of the above components, it is beneficial to further ensure the good overall performance of the glass fiber.

[0024] According to some preferred embodiments, the mixed glass powder comprises, by molar percentage or by mass percentage, 62-70% SiO2 (e.g., 62%, 63%, 64%, 65%, 66%, 67%, 68%, 69%, or 70%), 3-10% Al2O3 (e.g., 3%, 3.5%, 4%, 4.5%, 5%, 5.5%, 6%, 6.5%, 7%, 7.5%, 8%, 8.5%, 9%, 9.5%, or 10%), and 3-10% Li2O (e.g., 3%, 3.5%, 4%, 4.5%, 5%, 5.5%, 6%, 6.5%, 7%, 7.5%, 8%, or 8.5%). The following components are used: 0.5% to 5% MgO (e.g., 0%, 0.5%, 1.0%, 1.5%, 2.0%, 2.5%, 3.0%, 3.5%, 4.0%, 4.5%, or 5.0%), 0.5% to 2% CaO (e.g., 0.5%, 0.8%, 1.0%, 1.2%, 1.5%, 1.8%, or 2.0%), 1% to 4% TiO2 (e.g., 1.0%, 1.5%, 2.0%, 2.5%, 3.0%, 3.5%, or 4.0%), and 1% to 5% Na2O (e.g., 1.0%, 1.5%, 2.0%, 2.5%, 3.0%, 3.5%, or 4.0%). 0%, 4.5%, or 5.0% of K₂O (e.g., 0.5%, 0.8%, 1.0%, 1.2%, 1.5%, 1.8%, 2.0%, 2.2%, 2.5%, 2.8%, or 3.0%), 2% to 6% of P₂O₅ (e.g., 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, 5.5%, or 6%), 2% to 6% of ZrO₂ (e.g., 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, 5.5%, or 6%), and 0% to 2% of BaO (e.g., 0%, 0.01%, 0.05%, 0.08%, 1.0%, or 1.2%). 0-1% ZnO (e.g., 0%, 0.01%, 0.02%, 0.05%, 0.08%, 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, or 1.0%), 0-2% Sb2O3 (e.g., 0%, 0.01%, 0.05%, 0.08%, 1.0%, 1.2%, 1.5%, 1.8%, or 2.0%), and 0-2% Y2O3 (e.g., 0%, 0.01%, 0.05%, 0.08%, 1.0%, 1.2%, 1.5%, 1.8%, or 2.0%).

[0025] In this embodiment of the invention, by further screening and controlling each component, it is beneficial to guide the preferential formation of target microcrystalline phases such as lithium disilicate, lithium silicate, or petalite in the glass system. The presence of the above-mentioned microcrystalline phases is beneficial to significantly improve the elastic modulus of glass fibers. Furthermore, petalite, with its inherent low coefficient of thermal expansion and high thermal stability, enables the fiber as a whole to have an extremely low and controllable coefficient of thermal expansion and excellent thermal stability. In addition, the dense microstructure formed by the above-mentioned microcrystalline phases can reduce the dielectric constant of the material, ultimately enabling the glass fiber to have both high strength, low coefficient of thermal expansion, and excellent dielectric properties.

[0026] According to some preferred embodiments, the mixed glass powder comprises, by mass percentage, 65-70% SiO2, 5-10% Al2O3, 2-5% Li2O, 2-5% MgO, 0.5-1.5% CaO, 1-3% TiO2, 1-2% Na2O, 0.5-1.5% K2O, 3-5% P2O5, 4-6% ZrO2, 0.5-1.5% BaO, 0.1-1% ZnO, 0.5-1.5% Sb2O3, and 0-1% Y2O3 (for example, it can be 0%, 0.01%, 0.05%, 0.08%, or 1.0%).

[0027] In this embodiment of the invention, through precise design and synergistic control of the glass component system, a multiphase composite structure of four target microcrystalline phases—lithium disilicate, lithium silicate, lithium feldspar, and cordierite—can be simultaneously formed in the glass system. These composite phases, through functional complementarity, further enhance the elastic modulus of the glass fiber and significantly reduce its dielectric constant and coefficient of thermal expansion. Simultaneously, this component design further optimizes the high-temperature rheological properties of the glass, maintaining ideal viscosity of the melt during fiber drawing and improving the stability of the drawing process. The resulting composite microcrystalline glass fiber achieves a balance between high elastic modulus, low coefficient of thermal expansion, low dielectric loss, and good processability.

[0028] According to some preferred embodiments, in step (1), the melting temperature is 1500℃~1700℃ (for example, it can be 1500℃, 1600℃ or 1700℃), and the time is 2~24h (for example, it can be 2h, 6h, 8h, 12h, 15h, 18h, 20h or 24h); the homogenization and clarification temperature is 1500℃~1550℃ (for example, it can be 1500℃, 1510℃, 1520℃, 1530℃ or 1550℃), and the time is 1~2h (for example, it can be 1h, 1.5h or 2h).

[0029] According to some preferred embodiments, in step (2), the average particle size of the crystals in the microcrystalline glass melt is 1~100nm (for example, it can be 1nm, 5nm, 10nm, 30nm, 50nm, 80nm or 100nm), and the crystallinity is 10-40% (for example, it can be 10%, 20%, 30% or 40%).

[0030] According to some preferred embodiments, in step (2), the temperature of the gradient heating furnace is 600~1000℃ (for example, it can be 600℃, 700℃, 800℃, 900℃ or 1000℃), and the temperature of the heating furnace increases in a gradient from the mixed glass melt inlet area to the outlet area; the temperature of the heat preservation tank is 800℃~1000℃ (for example, it can be 800℃, 900℃ or 1000℃), and the heat preservation time is 1~4h (for example, it can be 1h, 2h, 3h or 4h).

[0031] According to some preferred embodiments, in step (3), the temperature of the temperature control plate is 1000℃~1500℃ (for example, it can be 1000℃, 1100℃, 1200℃, 1300℃, 1400℃ or 1500℃).

[0032] In this embodiment of the invention, a heat treatment method combining gradient temperature-controlled gradient heating furnace outflow and isothermal crystallization in a heat-insulating tank is employed. First, the mixed molten glass flows out through a gradient heating furnace. By controlling the temperature of each region in the furnace to increase gradually from the inflow end to the outflow end, it is beneficial to induce uniform volume nucleation of the glass, forming a high-density crystal nucleus base. Subsequently, the molten glass enters a heat-insulating tank at a specific crystallization temperature. Under a constant thermal environment, carefully proportioned oxides such as Li₂O, Al₂O₃, and MgO in the aforementioned glass components selectively precipitate composite crystalline phases such as lithium disilicate, lithium silicate, litharge, and cordierite. The formation of these composite crystalline phases not only significantly improves the elastic modulus of the fiber but also, through the complementary functions of each crystalline phase, synergistically ensures a low coefficient of thermal expansion and a low dielectric constant. Finally, the fully crystallized microcrystalline glass is stably drawn through a temperature-controlled baffle, thereby preparing glass fibers with a multiphase microcrystalline structure. Meanwhile, the heat treatment method that combines gradient temperature control with constant temperature crystallization in the heat preservation tank not only helps to achieve controllable crystallization of glass components, but also significantly improves the stability of the subsequent drawing process, thereby facilitating the industrial continuous production of high-performance microcrystalline glass fibers.

[0033] The multiphase microcrystalline glass fibers prepared in the embodiments of the present invention possess excellent elastic modulus, excellent dielectric properties, and a low coefficient of thermal expansion. Their elastic modulus is as high as 100 GPa or more, and their dielectric constant at 10 GHz is 4.0~7.0, and their coefficient of thermal expansion is 2.0~5.0 × 10⁻⁶. -6 / K can be used in the electronics industry to manufacture copper-clad laminates, printed circuit boards, etc., and can also be used as a reinforcing material in the field of high-frequency 5G / 6G communication.

[0034] To more clearly illustrate the technical solution and advantages of the present invention, the following detailed description of a multiphase microcrystalline glass fiber and its preparation method is provided through several embodiments.

[0035] Example 1 (1) According to the mass percentage, 68.0% SiO2, 8.0% Al2O3, 4.0% Li2O, 4.0% MgO, 1.0% CaO, 2.0% TiO2, 1.5% Na2O, 1.0% K2O, 4.0% P2O5, 5.0% ZrO2, 1.0% BaO, 0.5% ZnO, and 1.0% Sb2O3 are mixed to obtain mixed glass powder. The mixed glass powder is placed in a furnace and gradually heated to 1600℃. After melting in the furnace for 3 hours, it is homogenized and clarified for 12 hours in the temperature range of 1500℃-1550℃ to obtain mixed glass liquid. (2) The mixed glass melt flows out through a gradient heating furnace (the temperature of the furnace gradually increases from 600℃ to 1000℃ from the inlet to the outlet) and enters a heat preservation tank at 850℃ for 4 hours to crystallize, thus obtaining microcrystalline glass melt; (3) After the microcrystalline glass liquid flows out through the temperature-controlled baffle (the temperature of the temperature-controlled baffle is controlled to rise rapidly to 1200℃), it is drawn into fibers to obtain multiphase microcrystalline glass fibers containing lithium disilicate, lithium silicate, lithium feldspar and cordierite.

[0036] Example 2 (1) According to the mass percentage, 62.0% SiO2, 3.0% Al2O3, 10.0% Li2O, 1.0% CaO, 2.0% TiO2, 3.0% Na2O, 2.0% K2O, 5.0% P2O5, 6.0% ZrO2, 2.0% Sb2O3, and 2.0% Y2O3 are mixed to obtain mixed glass powder. The mixed glass powder is placed in a furnace and gradually heated to 1600℃. After melting in the furnace for 3 hours, it is homogenized and clarified for 12 hours in the temperature range of 1500℃-1550℃ to obtain mixed glass liquid. (2) The mixed glass melt flows out through a gradient heating furnace (the temperature of the furnace gradually increases from 600℃ to 1000℃ from the inlet to the outlet) and enters a 900℃ heat preservation tank for 4 hours to crystallize, thus obtaining microcrystalline glass melt; (3) After the microcrystalline glass liquid flows out through the temperature-controlled baffle (the temperature of the temperature-controlled baffle is controlled to rise rapidly to 1200℃), it is drawn into fibers to obtain microcrystalline glass fibers containing lithium disilicate.

[0037] Example 3 (1) According to the mass percentage, 70.0% SiO2, 12.0% Al2O3, 6.0% MgO, 3.0% TiO2, 0.5% Na2O, 0.5% K2O, 5.0% P2O5, 7.0% ZrO2 and 3.0% Sb2O3 are mixed to obtain mixed glass powder. The mixed glass powder is placed in a furnace and gradually heated to 1600℃. After melting in the furnace for 3 hours, it is homogenized and clarified for 12 hours in the temperature range of 1500℃-1550℃ to obtain mixed glass liquid. (2) The mixed glass melt flows out through a gradient heating furnace (the temperature of the furnace gradually increases from 600℃ to 1000℃ from the inlet to the outlet) and enters a heat preservation tank at 850℃ for 3 hours to crystallize, thus obtaining microcrystalline glass melt; (3) After the microcrystalline glass liquid flows out through the temperature-controlled baffle (the temperature of the temperature-controlled baffle is controlled to rise rapidly to 1200℃), it is drawn into fibers to obtain microcrystalline glass fibers containing cordierite.

[0038] Example 4 (1) According to the mass percentage, 72.0% SiO2, 10.0% Al2O3, 3.0% Li2O, 2.0% TiO2, 1.0% Na2O, 1.0% K2O, 4.0% P2O5, 5.0% ZrO2 and 2.0% Sb2O3 are mixed to obtain mixed glass powder. The mixed glass powder is placed in a furnace and gradually heated to 1600℃. After melting in the furnace for 3 hours, it is homogenized and clarified for 12 hours in the temperature range of 1500℃-1550℃ to obtain mixed glass liquid. (2) The mixed glass melt flows out through a gradient heating furnace (the temperature of the furnace gradually increases from 600℃ to 1000℃ from the inlet to the outlet) and enters a heat preservation tank at 950℃ for 4 hours to crystallize, thus obtaining microcrystalline glass melt. (3) After the microcrystalline glass liquid flows out through the temperature-controlled baffle (the temperature of the temperature-controlled baffle is controlled to rise rapidly to 1200℃), it is drawn into fibers to obtain microcrystalline glass fibers containing lepidolite.

[0039] Comparative Example 1 (1) According to the mass percentage, 65.0% SiO2, 6.0% Al2O3, 5.0% Li2O, 2.0% MgO, 1.0% CaO, 1.0% TiO2, 2.0% Na2O, 1.0% K2O, 3.0% P2O5, 4.0% ZrO2, 2.0% BaO, 1.0% ZnO, and 1.0% Sb2O3 are mixed to obtain mixed glass powder. The mixed glass powder is placed in a furnace and gradually heated to 1600℃. After melting in the furnace for 3 hours, it is homogenized and clarified for 12 hours in the temperature range of 1500℃-1550℃ to obtain mixed glass liquid. (2) After the mixed glass liquid flows out through the temperature-controlled baffle (the temperature of the temperature-controlled baffle is controlled to rise rapidly to 1200℃), it is drawn into fibers to obtain glass fibers without microcrystals.

[0040] The glass fibers prepared in the above embodiments and comparative examples were subjected to performance tests, and the test results are shown in Table 1: Elastic modulus test standard: GB / T 20310-2006 Preparation of glass fiber untwisted roving impregnated yarn specimens and determination of tensile strength; Dielectric constant test standard: GB / T 5597-1999 Test method for microwave complex dielectric constant of solid dielectrics; Standard for testing coefficient of thermal expansion: GB / T 16920-2015 Determination of the average linear thermal expansion coefficient of glass.

[0041] Table 1 As can be seen from Table 1, the composite microcrystalline glass fiber prepared in the embodiments of the present invention has excellent elastic modulus, excellent dielectric properties and low coefficient of thermal expansion, and can be used in the field of printed circuit boards. At the same time, due to its good dielectric properties, it can also be used as a reinforcing material in the field of high-frequency 5G / 6G communication.

[0042] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing multiphase microcrystalline glass fibers, characterized in that, The preparation method includes the following steps: (1) The mixed glass powder is placed in a kiln and successively melted and homogenized to obtain a mixed glass liquid; wherein the mixed glass powder includes SiO2, Al2O3, Li2O, P2O5, ZrO2, MgO, CaO, TiO2, Na2O, K2O, BaO, ZnO, Sb2O3, and Y2O3; (2) The mixed glass liquid is flowed out through a gradient heating furnace and enters a heat preservation tank for crystallization to obtain microcrystalline glass liquid; wherein the crystals in the microcrystalline glass liquid include at least one of lithium disilicate, lithium silicate, lithium feldspar or cordierite; (3) The microcrystalline glass liquid is drawn into fibers after flowing out through a temperature-controlled baffle plate to obtain the multiphase microcrystalline glass fiber.

2. The preparation method according to claim 1, characterized in that, In step (1), the mixed glass powder comprises, by mass percentage, 50-75% SiO2, 1-12% Al2O3, 2-11% Li2O, 0-6% MgO, 0-4% CaO, 0-4% TiO2, 0.1-5% Na2O, 0.1-4% K2O, 1-6% P2O5, 1-7% ZrO2, 0-3% BaO, 0-2% ZnO, 0-3% Sb2O3, and 0-2% Y2O3.

3. The preparation method according to claim 2, characterized in that, The mass percentages of SiO2, Li2O, Sb2O3, Y2O3, Na2O, and K2O satisfy the following relationship: 70%≤SiO2+Li2O≤80%, 1%≤Sb2O3+Y2O3≤4%, 1%≤Li2O+Na2O+K2O≤15%.

4. The preparation method according to claim 2 or 3, characterized in that, By mass percentage, the mixed glass powder comprises 62-70% SiO2, 3-10% Al2O3, 3-10% Li2O, 0-5% MgO, 0.5-2% CaO, 1-4% TiO2, 1-5% Na2O, 0.5-3% K2O, 2-6% P2O5, 2-6% ZrO2, 0-2% BaO, 0-1% ZnO, 0-2% Sb2O3, and 0-2% Y2O3.

5. The preparation method according to claim 4, characterized in that, By mass percentage, the mixed glass powder comprises 65-70% SiO2, 5-10% Al2O3, 2-5% Li2O, 2-5% MgO, 0.5-1.5% CaO, 1-3% TiO2, 1-2% Na2O, 0.5-1.5% K2O, 3-5% P2O5, 4-6% ZrO2, 0.5-1.5% BaO, 0.1-1% ZnO, 0.5-1.5% Sb2O3, and 0-1% Y2O3.

6. The preparation method according to claim 1, characterized in that, In step (1), the melting temperature is 1500℃~1700℃ and the time is 2~24h; The homogenization and clarification process takes place at a temperature of 1500℃ to 1550℃ for 1 to 2 hours.

7. The preparation method according to claim 1, characterized in that, In step (2), the average particle size of the crystals in the microcrystalline glass melt is 1~100nm and the crystallinity is 10-40%.

8. The preparation method according to claim 1, characterized in that, In step (2), the temperature of the gradient heating furnace is 800℃~1200℃, and the temperature of the furnace gradually increases from the inlet region to the outlet region of the mixed glass melt; and / or The temperature of the heat preservation tank is 800℃~1000℃, and the heat preservation time is 1~4h.

9. The preparation method according to claim 1, characterized in that, In step (3), the temperature of the temperature control plate is 1000℃~1500℃.

10. A multiphase microcrystalline glass fiber, characterized in that, The microcrystalline glass fiber is prepared by any one of the preparation methods of claims 1 to 9; wherein the crystal phase of the microcrystalline glass fiber includes at least one of lithium disilicate, lithium silicate, petalite, or cordierite.

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