Low-dielectric-loss microcrystalline glass and preparation method thereof

Abstract

The invention provides low-dielectric-loss microcrystalline glass and a preparation method thereof, and belongs to the technical field of microcrystalline glass preparation. The low-dielectric-loss glass ceramic comprises a main crystal phase and a secondary crystal phase, the main crystal phase is sodium nepheline, the secondary crystal phase comprises at least one of eucryptite, zirconium oxide and a beta quartz solid solution, and the mass ratio of the secondary crystal phase to the total mass of the main crystal phase and the secondary crystal phase is smaller than or equal to 40%; the dielectric loss tangent tan delta of the low dielectric loss glass ceramic is less than or equal to 0.005 under 5GHz, and the relative dielectric constant epsilon r is less than or equal to 7. The low-dielectric-loss microcrystalline glass has excellent low dielectric loss, excellent light transmittance, excellent mechanical properties and excellent signal transmission performance.

Description

Technical Field

[0001] This invention belongs to the field of microcrystalline glass preparation technology, specifically relating to a low dielectric loss microcrystalline glass and its preparation method. Background Technology

[0002] With the rapid development of high-frequency wireless communication technologies such as 5G and future 6G mobile communication, millimeter-wave radar, and high-speed data transmission (e.g., WiFi 6E / 7), and the increasing demand for high-performance display protection covers from consumer electronics (e.g., smartphones, tablets, wearable devices) and automotive displays (e.g., central control screens, dashboards, HUDs), more stringent requirements are being placed on the key performance characteristics of materials used in related electronic devices. Among these, a low relative permittivity (ε) is crucial. r High dielectric loss and extremely low dielectric loss tangent (tanδ) have become key indicators for core components such as substrates, packaging materials, and antenna covers in high-frequency applications, in order to minimize signal transmission delay, energy loss, and signal distortion, and ensure communication quality and speed.

[0003] Due to its excellent mechanical strength, chemical stability, adjustable coefficient of thermal expansion, and good optical properties, glass-ceramic is considered one of the ideal candidate materials for protective covers of high-end electronic devices (such as mobile phone front covers, back covers, and automotive display covers).

[0004] However, existing microcrystalline glass technologies still suffer from problems such as high high-frequency loss, high relative permittivity, low light transmittance, and high haze.

[0005] Therefore, there is still an urgent need for a method with high frequency, low loss, and low relative permittivity (ε). r ≤7) and microcrystalline glass with high light transmittance (≥89%) and low haze (≤0.2%). Summary of the Invention

[0006] Existing technologies struggle to precisely control nepheline (Na₂O·Al₂O₃·2SiO₂) as the main crystalline phase and to synergistically control the types and proportions of secondary crystalline phases such as lithium nepheline, zirconium oxide, and β-quartz solid solution in the total crystalline phase, in order to achieve optimal high-frequency, low-loss, and low relative permittivity (ε). r ≤7) and a balance with high transmittance (≥89%) and low haze (≤0.2%). Furthermore, the applicant discovered that the composition of the residual glass phase (especially alkali metal ions such as Na) + The content of Na2O is crucial to dielectric loss and subsequent chemical strengthening effect. However, existing technologies do not pay enough attention to the precise control of the Na2O content in the residual glass phase of the glass-ceramic before strengthening, which affects the mechanical properties (surface compressive stress, stress layer depth) of the strengthened product.

[0007] This invention relates to a low-dielectric-loss glass-ceramic, its preparation method, and its applications. Addressing the synergistic requirements of dielectric properties, optical transparency, and mechanical strength in 5G / 6G high-frequency communication, high-end electronic packaging, and biomedical fields, it aims to solve the problem of difficulty in synergistically optimizing transmittance, mechanical properties, and signal transmission performance in existing glass-ceramics due to excessively high dielectric loss (tanδ > 0.005) and insufficient microstructure control in high-frequency communication. It innovatively solves the technical bottlenecks of excessively high dielectric loss, insufficient transmittance due to uneven crystal phase distribution, and limited space for mechanical strengthening in existing glass-ceramics through a triple control mechanism of composition, structure, and process.

[0008] To address the aforementioned technical problems, this invention provides a low dielectric loss microcrystalline glass, its preparation method, and its applications.

[0009] In a first aspect, the present invention provides a low dielectric loss microcrystalline glass.

[0010] A low-dielectric-loss glass-ceramic comprises a primary crystalline phase and a secondary crystalline phase. The primary crystalline phase is sodium nepheline (NaAlSiO4), and the secondary crystalline phase comprises at least one of lithium nepheline (LiAlSiO4), zirconium oxide, and β-quartz solid solution. The secondary crystalline phase accounts for ≤40% of the total mass of the primary and secondary crystalline phases. The low-dielectric-loss glass-ceramic exhibits a dielectric loss tangent tanδ ≤0.005 at 5 GHz and a relative permittivity ε. r ≤7; Based on the total mass of the low dielectric loss glass-ceramic, the low dielectric loss glass-ceramic comprises the following components by mass percentage: SiO2: 40.0 wt%~50.0 wt% Al2O3: 26.0 wt%~31.0 wt%, Na2O: 10.0 wt%~13.0 wt%, Li2O: 4.5 wt%~8.5 wt% K2O: 0.1 wt%~2.0 wt% CaO: 0 wt%~2.0 wt% B2O3: 2.0 wt%~5.0 wt% ZrO2: 1.0 wt%~5.0 wt% P2O5: 2.5 wt%~6.0 wt%, and TiO2: 0 wt%~2 wt%.

[0011] As a preferred technical solution, the main crystalline phase of the microcrystalline glass is sodium nepheline (NaAlSiO4), and the secondary crystalline phase is selected from at least one of lithium nepheline (LiAlSiO4), zirconium oxide, or β-quartz solid solution, with a volume percentage ≤40%. By controlling the content of sodium nepheline crystalline phase and β-quartz solid solution, an optimal balance between high frequency and low loss, low relative permittivity and high transmittance and low haze is achieved.

[0012] In some embodiments, the SiO2 content, calculated based on the total mass of the low dielectric loss microcrystalline glass, is 40.0 wt%, 41.0 wt%, 42.0 wt%, 43.0 wt%, 44.0 wt%, 45.0 wt%, 46.0 wt%, 47.0 wt%, 48.0 wt%, 49.0 wt%, 50.0 wt%, or any value within a range consisting of any two of the above values.

[0013] In some embodiments, the Al2O3 content, calculated based on the total mass of the low dielectric loss microcrystalline glass, is 26.0 wt%, 27.0 wt%, 28.0 wt%, 29.0 wt%, 30.0 wt%, 31.0 wt%, or any value within a range consisting of any two of the above values.

[0014] In some embodiments, the Na2O content, calculated based on the total mass of the low dielectric loss microcrystalline glass, is 10.0 wt%, 11.0 wt%, 12.0 wt%, 13.0 wt%, or any value within a range consisting of any two of the above values.

[0015] In some embodiments, the Li2O content, calculated based on the total mass of the low dielectric loss microcrystalline glass, is 4.5 wt%, 5.0 wt%, 5.5 wt%, 6.0 wt%, 6.5 wt%, 7.0 wt%, 7.5 wt%, 8.0 wt%, 8.5 wt%, or any value within a range consisting of any two of the above values.

[0016] In some embodiments, the K2O content, calculated based on the total mass of the low dielectric loss microcrystalline glass, is 0.1 wt%, 1.5 wt%, 2.0 wt%, or any value within a range consisting of any two of the above values.

[0017] In some embodiments, the CaO content, calculated based on the total mass of the low dielectric loss microcrystalline glass, is 0 wt%, 0.5 wt%, 1.0 wt%, 1.5 wt%, 2.0 wt%, or any value within a range consisting of any two of the above values.

[0018] In some embodiments, the B2O3 content, calculated based on the total mass of the low dielectric loss microcrystalline glass, is 2.0 wt%, 2.5 wt%, 3.0 wt%, 3.5 wt%, 4.0 wt%, 4.5 wt%, 5.0 wt%, or any value within a range consisting of any two of the above values.

[0019] In some embodiments, the ZrO2 content, calculated based on the total mass of the low dielectric loss microcrystalline glass, is 1.0 wt%, 1.5 wt%, 2.0 wt%, 2.5 wt%, 3.0 wt%, 3.5 wt%, 4.0 wt%, 4.5 wt%, 5.0 wt%, or any value within a range consisting of any two of the above values.

[0020] In some embodiments, the P2O5 content, calculated based on the total mass of the low dielectric loss microcrystalline glass, is 2.5 wt%, 3.0 wt%, 3.5 wt%, 4.0 wt%, 4.5 wt%, 5.0 wt%, 5.5 wt%, 6.0 wt%, or any value within a range consisting of any two of the above values.

[0021] In some embodiments, the TiO2 content, calculated based on the total mass of the low dielectric loss microcrystalline glass, is 0 wt%, 0.5 wt%, 1.0 wt%, 1.5 wt%, 2 wt%, or any value within a range consisting of any two of the above values.

[0022] In some embodiments, the mass percentage content of the components of the low-dielectric-loss microcrystalline glass, calculated based on the total mass of the low-dielectric-loss microcrystalline glass, satisfies the following relationship: 17wt%≤Na2O + Li2O + K2O≤22wt%; 72wt%≤Al2O3 + SiO2 + B2O3≤80wt%.

[0023] In some embodiments, the total content of Na2O, Li2O, and K2O in the low dielectric loss glass-ceramic is 17wt% to 22wt%, and can be any value within the range of 17wt%, 17.5wt%, 17.6wt%, 17.7wt%, 17.8wt%, 17.9wt%, 18wt%, 18.5wt%, 19wt%, 19.1wt%, 19.2wt%, 19.3wt%, 19.4wt%, 19.5wt%, 20wt%, 21wt%, 22wt%, or any two of the above values.

[0024] SiO2, Al2O3, and B2O3 are the main network oxides and intermediate oxides of the base glass and glass-ceramic of this invention. Maintaining the total mass percentage of the three within a certain range can effectively ensure a large internal network structure of the glass-ceramic. In this invention, the total mass percentage of (Al2O3 + SiO2 + B2O3) in the low dielectric loss glass-ceramic is between 72wt% and 80wt%, which can be 72wt%, 72.5wt%, 73wt%, 73.5wt%, 74wt%, 74.1wt%, 74.5wt%, 75wt%, 76wt%, 76.2wt%, 77wt%, 78wt%, 79wt%, 80wt%, or any value within the range of any two of the above values.

[0025] In this invention, the specific contents and functions of SiO2, Al2O3, and B2O3 are different, wherein: In this invention, SiO2, as one of the main components of the network oxides in the base glass and glass-ceramics, is an important component in forming the Si-O tetrahedra and constructing the network structure. After crystallization, it forms β-lithium nepheline (LiAlSiO4), sodium nepheline, etc. Based on the raw materials involved in the embodiments of this invention, the mass percentage of SiO2 is 40.0% to 50.0%, preferably 42.0% to 48.0%, for example, it can be 40.0%, 41.0%, 42.0%, 43.0%, 44.0%, 45.0%, 46.0%, 47.0%, 48.0%, 49.0%, 50.0%, or any value within the range of any two of the above values.

[0026] In this invention, Al2O3 is an intermediate oxide in glass formation and a major component of crystal forms such as nepheline and lepidolite. It can significantly improve the thermal stability of base glass and glass-ceramics. Furthermore, since [AlO4] has a larger volume than [SiO4], it provides more space for ion exchange; therefore, alumina can promote ion exchange. Excessive Al2O3 content increases the viscosity of the glass, hindering melting. Based on the raw materials involved in the embodiments of this invention, the mass fraction of Al2O3 is 26.0%–31.0%, preferably 26.0%–29.0%. For example, it can be 26.0%, 27.0%, 28.0%, 29.0%, 30.0%, 31.0%, or any value within the range of any two of the above values.

[0027] In this invention, B2O3, as the network oxide of the glass, generally fills the voids in the silicon-oxygen tetrahedral framework. Its cation coordination remains largely unchanged, and some properties of its oxide can be considered constant. B2O3 helps to provide a base glass with a low melting temperature. Furthermore, adding B2O3 to the base glass can improve the damage resistance of the glass-ceramic and reduce its coefficient of thermal expansion; however, excessive amounts of B2O3 can compromise the stability of the base glass. The B2O3 content of this invention is 2-5%, specifically 2.0%, 2.1%, 2.2%, 2.3%, 2.4%, 2.5%, 2.6%, 2.7%, 2.8%, 2.9%, 3.0%, 3.1%, 3.2%, 3.3%, 3.4%, 3.5%, 3.6%, 3.7%, 3.8%, 3.9%, 4.0%, 4.1%, 4.2%, 4.3%, 4.4%, 4.5%, 4.6%, 4.7%, 4.8%, 4.9%, 5.0%, or any value within the range of any two of the above values.

[0028] In this invention, the three alkali metal oxides Na₂O, Li₂O, and K₂O are the outer oxides of the basic glass network. The total mass percentage of the three is controlled within a certain range, which can effectively ensure the degree of bond breaking of the bridging oxygen bonds inside the basic glass, break the original network structure of the basic glass, and promote crystallization of the basic glass during heat treatment. In this invention, the total mass percentage of (Na₂O, Li₂O, and K₂O) is 17.0% to 22.0%, which can be 17.0%, 18.0%, 19.0%, 20.0%, 21.0%, 22.0%, or any value within the range of any two of the above values.

[0029] By controlling the composition of Na2O and Li2O within a certain range, the proportion of Na2O and Li2O participating in ion exchange chemical strengthening in the residual glass phase of the glass-ceramic can be controlled within a certain range. This is very beneficial to the ion exchange of chemically strengthened glass-ceramics, which can significantly improve the mechanical properties of chemically strengthened glass-ceramics. At the same time, by controlling the average grain size, crystallinity, and proportion of certain crystal forms in the glass-ceramic, the excellent optical properties of the glass-ceramic can be guaranteed, fully meeting the mechanical and optical performance requirements of protective cover materials for consumer electronics products or automotive display devices.

[0030] The functions and compositions of Na₂O, Li₂O, and K₂O are not entirely the same. Specifically: Na₂O is one of the main components of nepheline (NaAlSiO₄) and an important element in the subsequent chemical strengthening process. Simultaneously, Na₂O is a flux during the high-temperature melting of the base glass, significantly reducing its melting temperature. In this invention, the mass percentage of Na₂O ranges from 10.0% to 13.0%, specifically 10.0%, 11.0%, 12.0%, 13.0%, or any value within the range of any two of the above values.

[0031] Li₂O is a highly reactive alkali metal oxide and an oxide of the glass network. In this invention, it is used as an additive to reduce the high-temperature viscosity of the base glass, which can significantly improve the high-temperature fluidity of the base glass. At the same time, Li⁺ can participate in the ion exchange chemical strengthening reaction in the microcrystalline glass provided by this invention, further enhancing the mechanical properties of the microcrystalline glass. In this invention, the Li₂O content is 4.5% to 8.5%, which can be any value within the range of 4.5%, 5.0%, 5.5%, 6.0%, 6.5%, 7.0%, 7.5%, 8.0%, 8.5%, or any two of the above values.

[0032] K2O can reduce the high-temperature viscosity of the base glass, significantly improving its formability and fluidity at high temperatures, while also significantly reducing the cracking rate. Specifically, adding a small amount of K2O can slow down crystallization during the molding of glass-ceramics and promote the formation of crystals such as nepheline during crystallization. When the K2O mass content exceeds 2.0%, potassium feldspar and other crystalline phases will form, harming its mechanical strength and optical properties. The mass percentage of K2O in the base glass involved in the embodiments of this invention ranges from 0.1% to 2.00%, preferably from 0.1% to 1.50%. Specifically, in this invention, it can be 0.1%, 0.12%, 0.14%, 0.16%, 0.18%, 1.0%, 1.2%, 1.4%, 1.6%, 1.8%, 2.0%, or any value within the range of any two of the above values.

[0033] In this invention, calcium oxide (CaO) acts as a key network modifier in the low-dielectric-loss microcrystalline glass system. It not only serves as a flux to reduce the high-temperature viscosity of the melt but also inhibits grain coarsening of the β-quartz solid solution, ensuring high light transmittance and low haze. Furthermore, it reduces the free oxygen concentration to suppress dielectric loss and adjusts the Na content in the residual glass phase. + The diffusion coefficient enhances the depth of chemical strengthening. In this invention, the CaO content ranges from 0 to 2.0%, specifically 0.0%, 0.2%, 0.4%, 0.6%, 0.8%, 1.0%, 1.2%, 1.4%, 1.6%, 1.8%, 2.0%, or any value within a range consisting of any two of the above values.

[0034] In this invention, ZrO2 is an intermediate oxide in glass formation, which can improve the chemical stability of glass, increase its hardness, and enhance its scratch and drop resistance. Simultaneously, due to its high cation charge and strong field, ZrO2 has a significant accumulation effect on the glass structure and is commonly used as a nucleating agent in glass-ceramics. However, excessive ZrO2 will greatly increase the viscosity of the glass, affecting its forming ability. In the embodiments of this invention, the mass percentage of ZrO2 ranges from 1.0% to 5.0%, specifically 1.0%, 1.2%, 1.4%, 1.6%, 1.8%, 2.0%, 2.2%, 2.4%, 2.6%, 2.8%, 3.0%, 3.2%, 3.4%, 3.6%, 3.8%, 4.0%, 4.2%, 4.4%, 4.8%, 5.0%, or any value within the range of any two of the above values.

[0035] In this invention, P2O5 can be used as a nucleating agent in base glass and glass-ceramics, which can promote phase separation and overall crystallization ability of base glass. If the P2O5 concentration is too low, the base glass will not easily crystallize, and crystals will only form from the surface inward at higher temperatures and lower viscosity. If the P2O5 concentration is too high, it will be difficult to control devitrification during cooling in the formation of base glass. In the embodiments of this invention, the mass percentage of P2O5 ranges from 2.5% to 6.0%, specifically 2.5%, 3.0%, 3.5%, 4.0%, 4.5%, 5.0%, 5.5%, 6.0%, or any value within the range of any two of the above values.

[0036] In this invention, TiO2 is one of the nucleating agents for crystal nucleation and growth in glass-ceramics. It can effectively promote the growth of crystal nuclei in the base glass during the nucleation and crystallization process, while improving the stability of the glass. The introduction of TiO2 effectively promotes the precipitation of crystal nuclei during the nucleation process. At the same time, the introduction of TiO2 can easily cause phase separation in the base glass, leading to crystallization and affecting the formation of the glass. In this invention, the content of TiO2 ranges from 0 to 2%, specifically 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1.0%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5%, 1.6%, 1.7%, 1.8%, 1.9%, 2.0%, or any value within the range of any two of the above values.

[0037] In some embodiments, the low dielectric loss glass crystal further includes a clarifying agent.

[0038] In some embodiments, the clarifying agent includes one or more of SnO2, NaCl, Sb2O3, As2O3, and sulfates.

[0039] In some embodiments, the sulfate includes at least one of sodium sulfate, barium sulfate, and calcium sulfate.

[0040] In some embodiments, the content of the clarifying agent is 0.1 wt% to 1.0 wt%, calculated based on the total mass of the low dielectric loss microcrystalline glass.

[0041] In some embodiments, the content of the clarifying agent, calculated based on the total mass of the low dielectric loss microcrystalline glass, is 0.1wt%, 0.2wt%, 0.3wt%, 0.4wt%, 0.5wt%, 0.6wt%, 0.7wt%, 0.8wt%, 0.9wt%, 1.0wt%, or any value within a range consisting of any two of the above values.

[0042] In some embodiments, the total content of SiO2, Al2O3, Na2O, Li2O, K2O, CaO, B2O3, ZrO2, P2O5, and TiO2 in the low dielectric loss microcrystalline glass is 100 wt%. In some embodiments, the total content of SiO2, Al2O3, Na2O, Li2O, K2O, CaO, B2O3, ZrO2, P2O5, TiO2, and clarifying agent in the low dielectric loss microcrystalline glass is 100 wt%.

[0043] In some embodiments, the low dielectric loss glass-ceramic comprises a primary crystalline phase, a secondary crystalline phase, and a residual glassy phase. In some embodiments, the low dielectric loss glass-ceramic is composed of a primary crystalline phase, a secondary crystalline phase, and a residual glassy phase.

[0044] In some embodiments, the overall crystallinity of the low dielectric loss glass-ceramic is 20% to 65%. In some embodiments, the overall crystallinity of the low dielectric loss glass-ceramic is 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, or 65%.

[0045] In some embodiments, the average grain size of the low dielectric loss microcrystalline glass is ≤40 nm.

[0046] Research has shown that the type, proportion, grain size, and distribution of the main and secondary crystalline phases in low-dielectric-loss glass-ceramics have a significant impact on their dielectric and optical properties (transmittance and haze). This invention optimizes the composition of each component in low-dielectric-loss glass-ceramics by screening and optimizing the composition of the main and secondary crystalline phases, thereby obtaining low-dielectric-loss glass-ceramics with suitable types, proportions, grain sizes, and distributions of the main and secondary crystalline phases, and thus optimizing the dielectric and optical properties of the low-dielectric-loss glass-ceramics.

[0047] In some preferred embodiments, the low dielectric loss microcrystalline glass comprises, by mass percentage, components from groups (1) to (6) based on the total mass of the low dielectric loss microcrystalline glass: Group (1): CaO: 0 wt%~1.5 wt%, ZrO2: 1.5 wt%~5.0 wt% P2O5: 2.5 wt%~4.2 wt%, TiO2: 0 wt%~0.5 wt%, and The total content of Na2O+Li2O+K2O is 17wt%~19.3wt%, and the total content of Al2O3+SiO2+B2O3 is 73wt%~76.2wt%. Group (2): CaO: 1 wt% ZrO2: 2 wt% P2O5: 3.5 wt% TiO2: 0.5 wt% Clarifying agent: 0.5 wt%, and The total content of Na2O+Li2O+K2O is 18wt%, and the total content of Al2O3+SiO2+B2O3 is 74.5wt%. Group (3): CaO: 1 wt% ZrO2: 1.5 wt% P2O5: 4.2 wt% TiO2: 0.3 wt% Clarifying agent: 0.2 wt%, and The total content of Na2O+Li2O+K2O was 19.3 wt%, and the total content of Al2O3+SiO2+B2O3 was 73.5 wt%. Group (4): ZrO2: 3.5 wt% P2O5: 2.5 wt% TiO2: 0.5 wt% Clarifying agent: 0.3 wt%, and The total content of Na2O+Li2O+K2O is 17 wt%, and the total content of Al2O3+SiO2+B2O3 is 76.2 wt%. Group (5): CaO: 0.5 wt% ZrO2: 5.0 wt% Clarifying agent: 0.4 wt%, and The total content of Na2O+Li2O+K2O is 17 wt%, and the total content of Al2O3+SiO2+B2O3 is 74.1 wt%. Group (6): CaO: 1.5 wt% ZrO2: 3.5 wt% P2O5: 3.5 wt% TiO2: 0.5 wt% Clarifying agent: 0.3 wt%, and The total content of Na2O+Li2O+K2O is 17.7 wt%, and the total content of Al2O3+SiO2+B2O3 is 73 wt%.

[0048] In some preferred embodiments, the first group (1) further includes the following contents: Na2O, Li2O, K2O, Al2O3, SiO2, and B2O3, respectively: Na2O: 10.5wt%~11.5wt%, Li2O: 4.8wt%~7.5wt%, K2O: 0.2wt%~1.5wt%, Al2O3: 26.0wt%~28.5wt%, SiO2: 42.0wt%~48.0wt%, and B2O3: 2.2wt%~4.0wt%.

[0049] In some preferred embodiments, the second group further includes the following contents of Na2O, Li2O, K2O, Al2O3, SiO2, and B2O3: SiO2: 44 wt%, Al2O3: 27.5 wt%, Na2O: 11 wt%, Li2O: 6 wt%, and K2O: 1 wt%.

[0050] In some preferred embodiments, the third group further comprises: Na2O, Li2O, K2O, Al2O3, SiO2, and B2O3 with the following contents: Na2O: 11 wt%, Li2O: 7.5 wt%, K2O: 0.8 wt%, Al2O3: 26.5 wt%, SiO2: 43 wt%, B2O3: 4.0 wt%; In some preferred embodiments, the fourth group further includes the following contents of Na2O, Li2O, K2O, Al2O3, SiO2, and B2O3: Na2O: 10.5 wt%, Li2O: 5 wt%, K2O: 1.5 wt%, Al2O3: 26 wt%, SiO2: 48 wt%, and B2O3: 2.2 wt%.

[0051] In some preferred embodiments, the fifth group further includes the following contents of Na2O, Li2O, K2O, Al2O3, SiO2, and B2O3: Na2O: 12 wt%, Li2O: 4.8 wt%, K2O: 0.2 wt%, Al2O3: 27 wt%, SiO2: 43.6 wt%, and B2O3: 3.5 wt%.

[0052] In some preferred embodiments, the group (6) further includes the following contents: Na2O, Li2O, K2O, Al2O3, SiO2, and B2O3, respectively: Na2O: 11.5 wt%, Li2O: 5 wt%, K2O: 1.2 wt%, Al2O3: 28.5 wt%, SiO2: 42 wt%, and B2O3: 2.5 wt%.

[0053] In some embodiments, the low dielectric loss glass crystal satisfies at least one of the following conditions: (1) When β-quartz solid solution is present, the average size of β-quartz solid solution grains is 5nm-30nm (e.g., 5 nm, 10 nm, 15 nm, 20 nm, 21 nm, 22 nm, 23 nm, 24 nm, 25 nm, 26 nm, 27 nm, 28 nm, 29 nm, 30 nm or any value between any two of these values); (2) The Na2O content in the residual glass phase is 0.5wt%-7wt% (e.g., 0.5 wt%, 1 wt%, 1.5 wt%, 2 wt%, 2.5 wt%, 3 wt%, 3.5 wt%, 4 wt%, 4.28 wt%, 4.5 wt%, 5 wt%, 5.5 wt%, 6 wt%, 6.5 wt%, 6.64 wt%, 7 wt%, or any value within the range of any two of these values); (3) The visible light transmittance of the 0.7 mm thick low dielectric loss microcrystalline glass is ≥89%, and the haze is ≤0.2%.

[0054] In some embodiments, when the overall crystallinity R of the microcrystalline glass is controlled between 20% and 65% (e.g., 20%, 25%, 30%, 31%, 32%, 33%, 34%, 35%, 40%, 41%, 42%, 43%, 44%, 45%, 46%, 47%, 48%, 49%, 50%, 55%, 60%, 65% or any one of any two values ​​therein), the average grain size is ≤40nm (e.g., 20nm~40nm, 22nm~35nm, 20 nm, 21 nm, 22 nm, 23 nm, 24 nm, 25 nm, 26 nm, 27 nm, 28 nm, 29 nm, 30 nm, 31nm, 32 nm, 33 nm, 34 nm, 35 nm, 36 nm, 37 nm, 38 nm, 39 nm or 40 nm).

[0055] In some embodiments, when the Na₂O content in the residual glass phase is 0.5 wt%-7 wt%, more preferably 4.28%-6.90%, the microcrystalline glass exhibits a dielectric loss tangent tanδ ≤ 0.004 and a relative permittivity ε at a high frequency of 5 GHz. r ≤7; transmittance T≥89% (0.7mm thickness) and haze H≤0.2% (0.7mm thickness) in the visible light band at 550nm. In some embodiments, the Na2O content in the residual glass phase is 4.28%~6.90%. In some embodiments, the Na2O content in the residual glass phase is 0.5 wt%, 1 wt%, 1.5 wt%, 2 wt%, 2.5 wt%, 3 wt%, 3.5 wt%, 4 wt%, 4.1 wt%, 4.2 wt%, 4.28 wt%, 4.3 wt%, 4.4 wt%, 4.5 wt%, 4.8 wt%, 4.83 wt%, 5 wt%, 5.5 wt%, 6 wt%, 6.09 wt%, 6.1 wt%, 6.2 wt%, 6.3 wt%, 6.4 wt%, 6.49 wt%, 6.5 wt%, 6.6 wt%, 6.7 wt%, 6.8 wt%, 6.9 wt%, 7 wt%, or any value within a range of any two of these values.

[0056] In some preferred embodiments, the Na₂O content in the residual glass phase is 0.5 wt%-7 wt%, which is beneficial for reducing the dielectric loss tangent tanδ ≤ 0.004 and the relative permittivity ε of the resulting low dielectric loss microcrystalline glass at high frequencies of 5 GHz. r The resulting low-dielectric-loss microcrystalline glass exhibits a dielectric loss tangent tanδ ≤ 0.004 and a relative permittivity ε at a high frequency of 5 GHz. r≤7 (e.g., ≤6.9, or 6.3~6.9). In some more preferred embodiments, the Na2O content in the residual glass phase is 4.28%~6.90%, which is more conducive to reducing the dielectric loss tangent tanδ≤0.004 and relative permittivity ε of the resulting low dielectric loss microcrystalline glass at high frequencies of 5GHz. r The resulting low-dielectric-loss microcrystalline glass exhibits a dielectric loss tangent tanδ ≤ 0.004 and a relative permittivity ε at a high frequency of 5 GHz. r ≤7 (e.g., ≤6.9, or 6.3~6.9) has unexpectedly superior technical effects.

[0057] Secondly, the present invention provides a method for preparing the aforementioned low dielectric loss microcrystalline glass.

[0058] A method for preparing a low dielectric loss microcrystalline glass as described in the first aspect, characterized by comprising the following steps: S1. Mix the corresponding component raw materials in the low dielectric loss microcrystalline glass evenly and melt them to obtain a glass melt. S2. Cool the glass melt obtained in step S1 to clarify and homogenize it, and then obtain the base glass after molding and annealing. S3. The base glass obtained in step S2 is subjected to heat treatment to obtain the low dielectric loss microcrystalline glass.

[0059] In some embodiments, the melting temperature of step S1 is 1450–1650°C. In some embodiments, the melting temperature of step S1 is 1450°C, 1500°C, 1550°C, 1600°C, 1650°C, or any value within a range of any two of these values.

[0060] In some embodiments, the cooling in step S2 is to cool to 1200–1450°C. In some embodiments, the cooling in step S2 is to cool to 1200°C, 1250°C, 1300°C, 1350°C, 1400°C, 1450°C, or any value within a range of any two of these values.

[0061] In some embodiments, the forming method of step S2 includes one of the following: float casting, rolling casting, overflow casting, and continuous melting casting.

[0062] In some embodiments, the heat treatment in step S3 includes nucleation followed by crystallization.

[0063] In some embodiments, the nucleation process includes holding at 500-580°C (e.g., 500°C, 510°C, 520°C, 530°C, 540°C, 550°C, 560°C, 570°C, 580°C) for 2-6 hours (e.g., 2 hours, 2.5 hours, 3 hours, 3.5 hours, 4 hours, 4.5 hours, 5 hours, 5.5 hours, 6 hours) for 2 hours.

[0064] In some embodiments, the crystallization treatment includes: heating at 1-5℃ / min (e.g., 1℃ / min, 2℃ / min, 3℃ / min, 4℃ / min, 5℃ / min) to 590℃-680℃ (e.g., 590℃, 600℃, 605℃, 610℃, 615℃, 620℃, 625℃, 630℃, 635℃, 640℃, 645℃, 650℃, 655℃, 660℃, 665℃, 670℃, 675℃, 680℃) and holding at that temperature for 0.25 hours-3 hours (e.g., 0.25 hours, 0.5 hours, 1 hour, 1.5 hours, 2 hours, 2.5 hours, 3 hours) to perform the crystallization treatment.

[0065] Thirdly, the present invention provides a reinforced microcrystalline glass.

[0066] A reinforced glass-ceramic, the method for preparing the reinforced glass-ceramic includes: subjecting the low dielectric loss glass-ceramic described in the first aspect or the low dielectric loss glass-ceramic prepared by the method described in the second aspect to ion exchange chemical reinforcement to obtain the reinforced glass-ceramic.

[0067] In some embodiments, the ion exchange chemical enhancement includes placing the low dielectric loss microcrystalline glass of the first aspect in a Na-containing environment. + Li + K + Ion exchange is carried out in a molten salt bath containing at least one of the ions at 380–560 °C. The resulting strengthened glass-ceramic exhibits enhanced mechanical properties.

[0068] In some embodiments, the salt used in the ion exchange chemical enhancement is a nitrate.

[0069] In some embodiments, the ion exchange chemically enhanced ion exchange is performed at a temperature of 380, 400°C, 410°C, 420°C, 430°C, 440°C, 450°C, 460°C, 470°C, 480°C, 490°C, 500°C, 510°C, 520°C, 530°C, 540°C, 550°C, 560°C, or any two of these values.

[0070] In some embodiments, the ion exchange time for ion exchange chemical enhancement is 0.5h-12h. In some embodiments, the ion exchange time for ion exchange chemical enhancement is 0.5h, 1h, 2h, 3h, 4h, 5h, 6h, 7h, 8h, 9h, 10h, 11h, 12h, or a range between any two of these values.

[0071] In some embodiments, when the Na₂O content in the residual glass phase is 0.5 wt%-7 wt%, more preferably 4.28%-6.90%, the resulting reinforced microcrystalline glass exhibits a dielectric loss tangent tanδ ≤ 0.004 and a relative permittivity ε at a high frequency of 5 GHz. r ≤7; in the visible light band at 550nm, transmittance T≥89% (0.7mm thickness) and haze H≤0.2% (0.7mm thickness).

[0072] In some preferred embodiments, the Na₂O content in the residual glass phase is 0.5 wt%-7 wt%, which is beneficial for reducing the dielectric loss tangent tanδ ≤ 0.004 and the relative permittivity ε of the resulting strengthened glass-ceramic at high frequencies of 5 GHz. r The resulting reinforced microcrystalline glass exhibits a dielectric loss tangent tanδ ≤ 0.004 and a relative permittivity ε at a high frequency of 5 GHz. r ≤7 (e.g., ≤6.9, or 6.3~6.9). In some more preferred embodiments, the Na2O content in the residual glass phase is 4.28%~6.90%, which is more conducive to reducing the dielectric loss tangent tanδ≤0.004 and relative permittivity ε of the obtained strengthened microcrystalline glass at high frequencies of 5GHz. r The resulting reinforced microcrystalline glass exhibits a dielectric loss tangent tanδ ≤ 0.004 and a relative permittivity ε at a high frequency of 5 GHz. r ≤7 (e.g., ≤6.9, or 6.3~6.9) has unexpectedly superior technical effects.

[0073] Fourthly, the present invention provides an application of the aforementioned low dielectric loss microcrystalline glass, the low dielectric loss microcrystalline glass prepared by the aforementioned method, or the aforementioned reinforced microcrystalline glass.

[0074] The application of a low dielectric loss microcrystalline glass as described in the first aspect, a low dielectric loss microcrystalline glass prepared by the preparation method described in the second aspect, or a reinforced microcrystalline glass prepared by the third aspect as a protective cover material for consumer electronics products or a protective cover material for automotive display devices.

[0075] Fifthly, the present invention provides a protective cover material for consumer electronics products or a protective cover material for automotive display devices.

[0076] A protective cover material for consumer electronics products or automotive display devices, comprising the low dielectric loss microcrystalline glass described in the first aspect, the low dielectric loss microcrystalline glass prepared by the preparation method described in the second aspect, or the reinforced microcrystalline glass obtained in the third aspect.

[0077] Beneficial effects Compared with the prior art, a certain embodiment of the present invention includes at least one of the following beneficial effects: (1) The raw materials provided in this invention are in the following proportions: SiO2: 40.0 wt%–50.0 wt%, Al2O3: 26.0 wt%–31.0 wt%, Na2O: 10.0 wt%–13.0 wt%, Li2O: 4.5 wt%–8.5 wt%, K2O: 0.1 wt%–2.0 wt%, CaO: 0 wt%–2.0 wt%, B2O3: 2.0 wt%–5.0 wt%, ZrO2: 1.0 wt%–5.0 wt%, P2O5: 2.5 wt%–6.0 wt%, and TiO2: 0 wt%–2 wt%; and the mass percentage content of the components of the low dielectric loss microcrystalline glass satisfies the following relationship: 17 wt% ≤ Na2O + Li2O + K2O ≤ 22 wt%; 72 wt% ≤ Al2O3 + SiO2 + The low dielectric loss microcrystalline glass and the strengthened microcrystalline glass prepared by (B2O3≤80wt%) have significantly better 550nm transmittance, haze, |B| value, 5GHz dielectric loss, and 5GHz relative permittivity. Furthermore, the strengthened microcrystalline glass prepared by using the raw materials in the proportions provided by this invention has significantly better CS and DOL_0, resulting in unexpected technical effects.

[0078] (2) The content of any raw material, the total content of Na2O + Li2O + K2O, and the total content of Al2O3 + SiO2 + B2O3 in the low dielectric loss glass-ceramic and the reinforced glass-ceramic do not fall within the range provided by this invention (SiO2: 40.0wt%~50.0wt%, Al2O3: 26.0wt%~31.0wt%, Na2O: 10.0wt%~13.0wt%, Li2O: 4.5wt%~8.5wt%, K2O: 0.1wt%~2.0wt%, CaO: 0wt%~2.0wt%, B2O3: 2.0wt%~5.0wt%, ZrO2: 1.0wt%~5.0wt%, P2O5: 2.5wt%~6.0wt%, and TiO2: 0wt%~2.0wt%). The low dielectric loss microcrystalline glass has a mass percentage content of 17wt% ≤ Na2O + Li2O + K2O ≤ 22wt%; 72wt% ≤ Al2O3 + SiO2 + B2O3 ≤ 80wt%. The resulting low dielectric loss microcrystalline glass exhibits significantly lower transmittance, haze, |B| value, 5GHz dielectric loss, and 5GHz relative permittivity compared to the low dielectric loss microcrystalline glass and reinforced microcrystalline glass provided by this invention. The content of each raw material provided by this invention, the total content of Na2O + Li2O + K2O, and the total content of Al2O3 + SiO2 + B2O3 (SiO2: 40.0wt%~50.0wt%, Al2O3: 26.0wt%~31.0wt%, Na2O...) are all significantly lower than those of the low dielectric loss microcrystalline glass and reinforced microcrystalline glass provided by this invention. The composition of the low dielectric loss microcrystalline glass is as follows: 10.0 wt%~13.0 wt%, Li2O: 4.5 wt%~8.5 wt%, K2O: 0.1 wt%~2.0 wt%, CaO: 0 wt%~2.0 wt%, B2O3: 2.0 wt%~5.0 wt%, ZrO2: 1.0 wt%~5.0 wt%, P2O5: 2.5 wt%~6.0 wt%, and TiO2: 0 wt%~2 wt%. The mass percentage content of the components in the low dielectric loss microcrystalline glass satisfies the following relationship: 17 wt% ≤ Na2O + Li2O + K2O ≤ 22 wt%; 72 wt% ≤ Al2O3 + SiO2 + B2O3 ≤ 80 wt%. The preparation of low dielectric loss microcrystalline glass and reinforced microcrystalline glass has unexpected technical effects.

[0079] (3) Compared with other contents of Na2O in the residual glass phase, the low dielectric loss microcrystalline glass and the strengthened microcrystalline glass obtained by using the Na2O content range in the residual glass phase provided by the present invention (0.5 wt%-7 wt%, preferably 4.28%~6.90%) have lower dielectric loss and relative permittivity, and have unexpectedly excellent technical effects.

[0080] (4) The present invention preferably uses the following components: SiO2: 42.0 wt%–48.0 wt%, Al2O3: 26.0 wt%–28.5 wt%, Na2O: 10.5 wt%–11.5 wt%, Li2O: 4.8 wt%–7.5 wt%, K2O: 0.2 wt%–1.5 wt%, CaO: 0 wt%–1.5 wt%, B2O3: 2.2 wt%–4.0 wt%, ZrO2: 1.5 wt%–5.0 wt%, P2O5: 2.5 wt%–4.2 wt%, TiO2: 0 wt%–0.5 wt%. The formulation of low dielectric loss glass-ceramics and reinforced glass-ceramics prepared with a total content of Na2O+Li2O+K2O of 17wt%~19.3wt% and a total content of Al2O3+SiO2+B2O3 of 73wt%~76.2wt% is more conducive to improving the 550nm transmittance, haze, |B| value, 5GHz dielectric loss, 5GHz relative permittivity and the CS and DOL_0 of the obtained low dielectric loss glass-ceramics and reinforced glass-ceramics.

[0081] Terminology Explanation Unless otherwise stated, the following terms and phrases as used herein are intended to have the following meanings: The term "multiple" means two or more, such as two, three, four or five.

[0082] In this invention, "room temperature" refers to ambient temperature, ranging from approximately 10°C to approximately 40°C. In some embodiments, "room temperature" refers to a temperature ranging from approximately 15°C to approximately 35°C; in some embodiments, "room temperature" refers to a temperature ranging from approximately 20°C to approximately 30°C; in some embodiments, "room temperature" refers to a temperature ranging from approximately 20°C to approximately 35°C; in other embodiments, "room temperature" refers to a temperature ranging from approximately 25°C to approximately 30°C; in other embodiments, "room temperature" refers to a temperature ranging from approximately 22°C to approximately 28°C; in other embodiments, "room temperature" refers to a temperature ranging from approximately 24°C to approximately 26°C; and in still other embodiments, "room temperature" refers to 10°C, 15°C, 20°C, 25°C, 30°C, 35°C, 40°C, etc.

[0083] The term “and / or” should be understood to mean any one of the options or any combination of two or more of the options.

[0084] The terms "optional" or "optionally" refer to an event or situation that may, but is not necessarily, occur, as described below, and the description includes both the possibility that the event or situation occurs and the possibility that it does not occur. For example, "optionally condensing agent" means that a condensing agent may or may not be present.

[0085] In the foregoing description of this invention, all figures disclosed herein, whether or not the words “approximately” or “about” are used, are approximate values. Based on the disclosed figures, the value of each figure may vary by less than ±10% or by a difference that is considered reasonable by those skilled in the art, such as ±1%, ±2%, ±3%, ±4%, or ±5%.

[0086] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0087] Base glass: Glass that has been uniformly mixed with compounds containing the oxides, melted at high temperature and cast, rolled or drawn, and annealed without nucleation crystallization heat treatment or ion exchange strengthening treatment.

[0088] Glass-ceramics, also known as glass-ceramics, are a type of solid composite material that contains both glass phase and crystalline phase (microcrystalline phase, crystalline phase) by subjecting a base glass to controlled crystallization heat treatment with a set target.

[0089] Nucleation: The process of heat treatment to grow tiny crystal nuclei from nucleating material in a base glass.

[0090] Crystallization: The process of growing a certain type of crystal on the basis of a crystal nucleus by heat treatment of a base glass.

[0091] Crystal phase: Crystal phase is the microscopic structure of crystals, and is a general term for the parts composed of a large number of crystalline solid phases.

[0092] Transmittance (TR): The ratio of the radiant energy projected onto and transmitted through an object to the total radiant energy projected onto the object as the incident luminous flux travels from the incident surface of the irradiated surface to the other side. Detailed Implementation

[0093] To enable those skilled in the art to better understand the technical solutions of the present invention, some non-limiting embodiments are further disclosed below to provide a more detailed description of the present invention.

[0094] The scope of each component (ingredient) of the matrix glass, microcrystalline glass, and microcrystalline glass articles of the present invention will be described below. In this specification, unless otherwise specified, the content of each component is expressed as a weight percentage (wt%) relative to the total amount of the matrix glass, microcrystalline glass, or microcrystalline glass article as a component of oxides. Here, "composition converted to oxides" means that when oxides, complex salts, and hydroxides used as raw materials for the matrix glass, microcrystalline glass, or microcrystalline glass articles of the present invention decompose and transform into oxides upon melting, the total amount of such oxides is taken as 100%. Furthermore, in this specification, when referred to simply as "glass," it refers to the matrix glass before crystallization (i.e., crystallization process treatment); after crystallization (i.e., crystallization process treatment), it is referred to as microcrystalline glass; and microcrystalline glass articles refer to products obtained by chemically strengthening microcrystalline glass.

[0095] All reagents used in this invention can be purchased from the market, synthesized according to existing technology, or prepared by the methods described in this invention.

[0096] I. Instruments, Equipment and Testing Methods Glass thickness: determined by micrometer measurement. The thickness change of the glass ceramic before and after chemical strengthening is very small and can be ignored.

[0097] Crystal content testing: The glass-ceramic sample is tested using an X-ray diffractometer to obtain the XRD diffraction peak curve. The X-ray diffraction result file (RAW format) is then imported into X-ray diffraction data refinement software (such as Gsas, Fullprof, or Maud) for fitting and calculation. The crystal content in the glass-ceramic sample can then be obtained. The ratio of the fitted crystal phase peak area to the fitted total peak area is the crystal content. The diffraction angle range used in this invention is 2θ = 10–80°, the scanning speed is 10° / min, the operating voltage is 40KV, and the operating current is 30mA.

[0098] The average grain size is obtained by testing the glass-ceramic sample with an X-ray diffractometer and using the Scherrer formula D=Kλ / (βcosθ) to obtain the average grain size from the XRD test results, where λ is the X-ray wavelength, β is the peak half-width at half-maximum, and K=0.89.

[0099] Overall crystallinity: refers to the mass percentage of all crystalline phases in the glass-ceramic.

[0100] Crystal phase: Crystal phase is the microscopic structure of crystals, and is a general term for the parts composed of a large number of crystalline solid phases.

[0101] DOL_0: Compressive stress layer depth, also known as compressive stress layer depth, refers to the distance from any surface of the glass-ceramic material to the point near which the compressive stress is zero. It is obtained by measuring with an SLP 2000 stress meter. The unit is μm.

[0102] Surface compressive stress (CS): After chemical strengthening, smaller alkali metal ions on the surface of glass ceramics are replaced with larger alkali metal ions. Due to the crowding effect of the larger alkali metal ions, compressive stress is generated on the glass surface, which is called surface compressive stress. Surface CS is measured by an SLP 2000 stress meter, and the unit is MPa.

[0103] Dielectric loss tangent (tanδ): This is a key parameter measuring the degree of energy loss of a dielectric material in an alternating electric field. Its detection method is the resonant cavity method using network analysis, directly calculating the parameter by observing the resonant peak shift and Q-value change before and after sample placement. The instrument used in this invention is a DZ-17E5080B ENA vector network analyzer.

[0104] Relative permittivity (ε) r The permittivity (ε) is a core parameter characterizing the polarization capability of dielectric materials, defined as the ratio of the material's permittivity (ε) to its vacuum permittivity (ε0). r = ε / ε0), which directly affects the electric field distribution, signal propagation speed, and device size design.

[0105] Transmittance testing method: The transmittance of the glass ceramic was tested using professional testing instruments according to the standard GB / T 7962.12-2010 "Test Methods for Colorless Optical Glass Part 12: Internal Spectral Transmittance". The testing instrument used in this invention is a Konica Minolta CM-3600A spectrophotometer. In the embodiments and comparative examples of this invention, the transmittance of the microcrystalline glass at wavelengths of 400–1000 nm or 550 nm is the average of the transmittance measured at wavelengths of 400–1000 nm or 550 nm for multiple glass samples from the same batch. At least 5 samples were taken from each batch of microcrystalline glass for testing.

[0106] Haze detection method: Haze of glass refers to the percentage of transmitted light intensity that deviates from the incident light by more than 2.5° out of the total transmitted light intensity. It is an important parameter of the optical transparency of transparent or translucent materials. Higher haze means a decrease in film gloss and transparency, especially image quality. The testing instrument used in this invention is a benchtop spectrophotometer CM-3600A.

[0107] B-value: In LAB (Laser Absolute Barometer), the B-value indicates the degree to which an object's color leans towards the yellow-blue axis. A positive value indicates a yellowish bias, while a negative value indicates a blueish bias. The larger the absolute value, the more significant the bias. The B-value testing instrument used in this invention is a Konica Minolta CM-3600A spectrophotometer.

[0108] Examples and Comparative Examples: Preparation of Low Dielectric Loss Glass Crystals and Strengthened Glass Crystals 1. Preparation of low dielectric loss glass-ceramics Formula: See Table 1.

[0109] Table 1: Formulation of Low Dielectric Loss Microcrystalline Glass

[0110] Preparation method: S1. Mix the corresponding raw materials in the low dielectric loss microcrystalline glass evenly and melt them at 1600℃ for 4 hours to obtain glass melt. S2. Cool the molten liquid obtained in step S1 to 1450℃ to clarify and homogenize it, and then obtain the base glass after molding and annealing. S3. The base glass obtained in step S2 is subjected to heat treatment (first nucleation treatment, then crystallization treatment; the temperature and time of nucleation treatment and crystallization treatment are shown in Table 2) to obtain the low dielectric loss microcrystalline glass.

[0111] The crystal phase, overall crystallinity, average grain size, and Na2O content in the residual glass phase of the obtained low dielectric loss microcrystalline glass are shown in Table 2.

[0112] Table 2: Heat Treatment Process and Results

[0113] 2. Preparation of reinforced glass-ceramics The low dielectric loss microcrystalline glass obtained in the above examples and comparative examples was placed in a chemically strengthened molten salt for ion exchange (the composition of the chemically strengthened molten salt, the chemical strengthening temperature and time are shown in Table 3) to obtain strengthened microcrystalline glass. The CS, DOL_0, 550nm transmittance, haze, |B| value, 5GHz dielectric loss, and 5GHz relative permittivity of the obtained strengthened microcrystalline glass were measured, and the results are shown in Table 3.

[0114] Table 3: Strengthening process and properties of strengthened glass-ceramics

[0115] in conclusion: (1) Compared with low dielectric loss glass-ceramics and reinforced glass-ceramics prepared from raw materials in other proportions, the raw materials provided in this invention (SiO2: 40.0wt%~50.0wt%, Al2O3: 26.0wt%~31.0wt%, Na2O: 10.0wt%~13.0wt%, Li2O: 4.5wt%~8.5wt%, K2O: 0.1wt%~2.0wt%, CaO: 0wt%~2.0wt%, B2O3: 2.0wt%~5.0wt%, ZrO2: 1.0wt%~5.0wt%, P2O5: 2.5wt%~6.0wt%, and TiO2: 0wt%~2wt%) are used; and the mass percentage content of the components of the low dielectric loss glass-ceramics satisfies the following relationship: 17wt%≤Na2O + Li2O + The low dielectric loss microcrystalline glass and reinforced microcrystalline glass prepared by K2O≤22wt%; 72wt%≤Al2O3 + SiO2 + B2O3≤80wt% have significantly better 550nm transmittance, haze, |B| value, 5GHz dielectric loss, and 5GHz relative permittivity. Furthermore, the reinforced microcrystalline glass prepared by using the raw materials in the proportions provided by this invention has significantly better CS and DOL_0, resulting in unexpected technical effects.

[0116] (2) The content of any raw material, the total content of Na2O + Li2O + K2O, and the total content of Al2O3 + SiO2 + B2O3 in the low dielectric loss microcrystalline glass and the reinforced microcrystalline glass do not fall within the range provided by the present invention (see point (1) of the conclusion). The 550nm transmittance, haze, |B| value, 5GHz dielectric loss, and 5GHz relative permittivity of the obtained low dielectric loss microcrystalline glass and the 550nm transmittance, haze, |B| value, 5GHz dielectric loss, 5GHz relative permittivity, CS and DOL_0 of the obtained reinforced microcrystalline glass are significantly worse than those of the low dielectric loss microcrystalline glass and the reinforced microcrystalline glass provided by the present invention. The preparation of low dielectric loss microcrystalline glass and reinforced microcrystalline glass using the content of each raw material, the total content of Na2O + Li2O + K2O, and the total content of Al2O3 + SiO2 + B2O3 (see point (1) of the conclusion) provided by the present invention has unexpected technical effects.

[0117] (3) Compared with other contents of Na2O in the residual glass phase, the low dielectric loss microcrystalline glass and the strengthened microcrystalline glass obtained by using the Na2O content range in the residual glass phase provided by the present invention (0.5 wt%-7 wt%, preferably 4.28%~6.90%) have lower dielectric loss and relative permittivity, and have unexpectedly excellent technical effects.

[0118] (4) The present invention preferably uses the following components: SiO2: 42.0 wt%–48.0 wt%, Al2O3: 26.0 wt%–28.5 wt%, Na2O: 10.5 wt%–11.5 wt%, Li2O: 4.8 wt%–7.5 wt%, K2O: 0.2 wt%–1.5 wt%, CaO: 0 wt%–1.5 wt%, B2O3: 2.2 wt%–4.0 wt%, ZrO2: 1.5 wt%–5.0 wt%, P2O5: 2.5 wt%–4.2 wt%, TiO2: 0 wt%–0.5 wt%. The formulation of low dielectric loss glass-ceramics and reinforced glass-ceramics prepared with a total content of Na2O+Li2O+K2O of 17wt%~19.3wt% and a total content of Al2O3+SiO2+B2O3 of 73wt%~76.2wt% is more conducive to improving the 550nm transmittance, haze, |B| value, 5GHz dielectric loss, 5GHz relative permittivity and the CS and DOL_0 of the obtained low dielectric loss glass-ceramics and reinforced glass-ceramics.

[0119] The method of this invention has been described through preferred embodiments. Those skilled in the art will readily be able to modify or appropriately alter and combine the methods and applications described herein within the scope, spirit, and context of this invention to implement and apply the technology of this invention. Those skilled in the art can refer to the content herein to appropriately improve process parameters. It should be particularly noted that all similar substitutions and modifications are obvious to those skilled in the art and are considered to be included within the scope of this invention.

Claims

1. A low dielectric loss microcrystalline glass, characterized in that, The low-dielectric-loss glass-ceramic comprises a primary crystalline phase and a secondary crystalline phase. The primary crystalline phase is nepheline, and the secondary crystalline phase includes at least one of lithium nepheline, zirconium oxide, and β-quartz solid solution. The mass percentage of the secondary crystalline phase in the total mass of the primary and secondary crystalline phases is ≤40%. At 5 GHz, the low-dielectric-loss glass-ceramic exhibits a dielectric loss tangent tanδ ≤0.005 and a relative permittivity ε. r ≤7; Based on the total mass of the low dielectric loss glass-ceramic, the low dielectric loss glass-ceramic comprises the following components by mass percentage: SiO2: 40.0wt%~50.0wt% Al2O3: 26.0 wt%~31.0wt%, Na2O: 10.0 wt%~13.0wt%, Li2O: 4.5 wt%~8.5 wt%, K2O: 0.1 wt%~2.0 wt% CaO: 0 wt%~2.0 wt% B2O3: 2.0 wt%~5.0 wt% ZrO2: 1.0 wt%~5.0 wt% P2O5: 2.5 wt%~6.0 wt%, and TiO2: 0 wt%~2 wt%.

2. The low dielectric loss glass-ceramic according to claim 1, wherein the mass percentage content of the components of the low dielectric loss glass-ceramic, calculated based on the total mass of the low dielectric loss glass-ceramic, satisfies the following relationship: 17wt%≤Na2O + Li2O + K2O≤22wt%; 72wt%≤Al2O3 + SiO2 + B2O3≤80wt%.

3. The low dielectric loss microcrystalline glass according to any one of claims 1-2, characterized in that, The overall crystallinity of the low dielectric loss microcrystalline glass is 20%–65%; and / or The average grain size of the low dielectric loss microcrystalline glass is ≤40nm; and / or The low dielectric loss microcrystalline glass further includes a clarifying agent; and / or The clarifying agent includes one or more of SnO2, NaCl, Sb2O3, As2O3, and sulfates; and / or The sulfate includes at least one of sodium sulfate, barium sulfate, and calcium sulfate; and / or Based on the total mass of the low dielectric loss microcrystalline glass, the content of the clarifying agent is 0.1 wt% to 1.0 wt%.

4. The low dielectric loss glass-ceramic according to claim 1, wherein the low dielectric loss glass-ceramic comprises, by mass percentage, components from groups (1) to (6) based on the total mass of the low dielectric loss glass-ceramic: Group (1): CaO: 0 wt%~1.5 wt%, ZrO2: 1.5 wt%~5.0 wt% P2O5: 2.5 wt%~4.2 wt%, TiO2: 0 wt%~0.5 wt%, and The total content of Na2O+Li2O+K2O is 17wt%~19.3wt%, and the total content of Al2O3+SiO2+B2O3 is 73wt%~76.2wt%. Preferably, the first group further includes: The contents of Na2O, Li2O, K2O, Al2O3, SiO2, and B2O3 are as follows: Na2O: 10.5wt%–11.5wt%, Li2O: 4.8wt%–7.5wt%, K2O: 0.2wt%–1.5wt%, Al2O3: 26.0wt%–28.5wt%, SiO2: 42.0wt%–48.0wt%, and B2O3: 2.2wt%–4.0wt%. Group (2): CaO: 1 wt% ZrO2: 2 wt% P2O5: 3.5 wt% TiO2: 0.5 wt% Clarifying agent: 0.5 wt%, and The total content of Na2O+Li2O+K2O is 18wt%, and the total content of Al2O3+SiO2+B2O3 is 74.5wt%. Preferably, the second group further comprises the following: the contents of Na2O, Li2O, K2O, Al2O3, SiO2, and B2O3 are as follows: SiO2: 44 wt%, Al2O3: 27.5 wt%, Na2O: 11 wt%, Li2O: 6 wt%, K2O: 1 wt%. Group (3): CaO: 1 wt% ZrO2: 1.5 wt% P2O5: 4.2 wt% TiO2: 0.3 wt% Clarifying agent: 0.2 wt%, and The total content of Na2O+Li2O+K2O was 19.3 wt%, and the total content of Al2O3+SiO2+B2O3 was 73.5 wt%. Preferably, the third group further comprises the following: the contents of Na2O, Li2O, K2O, Al2O3, SiO2, and B2O3 are as follows: Na2O: 11 wt%, Li2O: 7.5 wt%, K2O: 0.8 wt%, Al2O3: 26.5 wt%, SiO2: 43 wt%, B2O3: 4.0 wt%; Group (4): ZrO2: 3.5 wt% P2O5: 2.5 wt% TiO2: 0.5 wt% Clarifying agent: 0.3 wt%, and The total content of Na2O+Li2O+K2O is 17 wt%, and the total content of Al2O3+SiO2+B2O3 is 76.2 wt%. Preferably, the fourth group further comprises the following contents: Na2O, Li2O, K2O, Al2O3, SiO2, and B2O3, respectively: Na2O: 10.5 wt%, Li2O: 5 wt%, K2O: 1.5 wt%, Al2O3: 26 wt%, SiO2: 48 wt%, B2O3: 2.2 wt%; Group (5): CaO: 0.5 wt% ZrO2: 5.0 wt% Clarifying agent: 0.4 wt%, and The total content of Na2O+Li2O+K2O is 17 wt%, and the total content of Al2O3+SiO2+B2O3 is 74.1 wt%. Preferably, the fifth group further comprises the following contents: Na2O, Li2O, K2O, Al2O3, SiO2, and B2O3, respectively: Na2O: 12 wt%, Li2O: 4.8 wt%, K2O: 0.2 wt%, Al2O3: 27 wt%, SiO2: 43.6 wt%, B2O3: 3.5 wt%; Group (6): CaO: 1.5 wt% ZrO2: 3.5 wt% P2O5: 3.5 wt% TiO2: 0.5 wt% Clarifying agent: 0.3 wt%, and The total content of Na2O+Li2O+K2O was 17.7 wt%, and the total content of Al2O3+SiO2+B2O3 was 73 wt%. Preferably, the sixth group further includes the following contents of Na2O, Li2O, K2O, Al2O3, SiO2, and B2O3: Na2O: 11.5 wt%, Li2O: 5 wt%, K2O: 1.2 wt%, Al2O3: 28.5 wt%, SiO2: 42 wt%, and B2O3: 2.5 wt%.

5. The low dielectric loss microcrystalline glass according to any one of claims 1-4, characterized in that, The low dielectric loss glass-ceramic satisfies at least one of the following conditions: (1) When β-quartz solid solution is present, the average size of β-quartz solid solution grains is 5nm-30nm; (2) The low dielectric loss glass-ceramic also includes a residual glass phase, and the Na2O content in the residual glass phase is 0.5wt%-7wt% based on the mass of the residual glass phase; (3) The visible light transmittance of the 0.7 mm thick low dielectric loss microcrystalline glass is ≥89%, and the haze is ≤0.2%.

6. A method for preparing a low dielectric loss microcrystalline glass according to any one of claims 1-5, characterized in that, Includes the following steps: S1. Mix the corresponding component raw materials in the low dielectric loss microcrystalline glass evenly and melt them to obtain a glass melt. S2. Cool the glass melt obtained in step S1 to clarify and homogenize it, and then obtain the base glass after molding and annealing. S3. The base glass obtained in step S2 is subjected to heat treatment to obtain the low dielectric loss microcrystalline glass.

7. The preparation method according to claim 6, wherein the melting temperature of step S1 is 1450–1650 °C; and / or Optionally, the cooling in step S2 is to cool to 1200℃~1450℃; and / or Optionally, the forming method in step S2 includes one of the following: float casting, rolling casting, overflow casting, and continuous melting casting; and / or Optionally, the heat treatment in step S3 includes nucleation followed by crystallization. Optionally, the nucleation process includes holding at 500-580°C for 2-6 hours. Optionally, the crystallization process includes: The temperature is increased to 590-680℃ at a rate of 1-5℃ / min and held for 0.25-3 hours for crystallization treatment.

8. A reinforced microcrystalline glass, characterized in that, The method for preparing the reinforced glass-ceramic includes: subjecting the glass-ceramic according to any one of claims 1-5 or the glass-ceramic prepared by the method according to any one of claims 6-7 to ion exchange chemical strengthening to obtain the reinforced glass-ceramic.

9. The use of the low dielectric loss microcrystalline glass according to any one of claims 1-5, or the low dielectric loss microcrystalline glass prepared by the preparation method according to any one of claims 6-7, or the reinforced microcrystalline glass obtained by claim 8, as a protective cover material for consumer electronics products or a protective cover material for automotive display devices.

10. A protective cover material for consumer electronics products or automotive display devices, characterized in that, Includes the low dielectric loss microcrystalline glass according to any one of claims 1-5, or the low dielectric loss microcrystalline glass prepared by the preparation method according to any one of claims 6-7, or the reinforced microcrystalline glass obtained according to claim 8.

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