阅读说明：本技术 一种可用于化学强化的低介电常数的玻璃、强化玻璃 (Low-dielectric-constant glass capable of being used for chemical strengthening and strengthened glass ) 是由 胡伟 覃文城 谈宝权 陈芳华 于 2019-04-30 设计创作，主要内容包括：本发明公开了一种可用于化学强化的低介电常数的玻璃、强化玻璃。所述玻璃经化学强化后在室温和频率为50GHz下的介电常数为4.8～6.5介电损耗角正切小于或等于3×10<Sup>-2</Sup>,所述玻璃包含SiO<Sub>2</Sub>、Al<Sub>2</Sub>O<Sub>3</Sub>、Na<Sub>2</Sub>O、Li<Sub>2</Sub>O,其中,按摩尔百分数计,Na<Sub>2</Sub>O+Li<Sub>2</Sub>O的含量小于等于12mol％,SiO<Sub>2</Sub>+Al<Sub>2</Sub>O<Sub>3</Sub>的含量大于等于78mol％。所述玻璃经过化学强化后可以得到机械强度高且介电常数低的强化玻璃,而这种强化玻璃则非常适用于5G通讯制式下的通讯终端上的器件。(The invention discloses glass with low dielectric constant and tempered glass which can be used for chemical strengthening. The dielectric constant of the chemically strengthened glass at room temperature and 50GHz is 4.8-6.5, and the dielectric loss tangent is less than or equal to 3 multiplied by 10 ‑2 Said glass comprising SiO 2 、Al 2 O 3 、Na 2 O、Li 2 O, wherein, in mol percent, Na 2 O+Li 2 O content of 12 mol% or less, SiO 2 +Al 2 O 3 The content of (B) is not less than 78 mol%. The glass can be chemically strengthened to obtain strengthened glass with high mechanical strength and low dielectric constant, and the strengthened glass is very suitable for devices on communication terminals under a 5G communication system.)

1. The glass with low dielectric constant for chemical strengthening is characterized in that the dielectric constant of the glass is 4.8-6.5 and the dielectric loss tangent is less than or equal to 3 multiplied by 10 at room temperature and 50GHz after the glass is chemically strengthened^-2Said glass comprising SiO₂、Al₂O₃、Na₂O, wherein, in mol percent, Na₂O content of 1-6 mol%, SiO₂+Al₂O₃The content of (B) is not less than 78 mol%.

2. The glass with low dielectric constant for chemical strengthening of claim 1, wherein the glass has a dielectric constant of 4.8 to 6.5 and a dielectric loss tangent of 2 x 10 or less at room temperature and a frequency of 20GHz after chemical strengthening^-2。

3. The glass with low dielectric constant for chemical strengthening of claim 1, wherein the glass has a dielectric constant of 4.8 to 6.5 and a dielectric loss tangent of 8 x 10 or less at room temperature and a frequency of 2GHz after chemical strengthening^-3。

4. The glass with low dielectric constant for chemical strengthening of claim 1, wherein the glass has a dielectric constant of 4.8 to 6.5 and a dielectric loss tangent of 5 x 10 or less at 5000MHz after chemical strengthening at room temperature and at a frequency of 5000MHz ^-3。

5. The glass of claim 1, wherein the chemically strengthened glass has a dielectric constant of 4.8 to 6.5 and a dielectric loss tangent of 3 x 10 or less at 3000MHz at room temperature and frequency after chemical strengthening^-3。

6. The glass of claim 1, wherein the glass comprises, in mole percent, 65 to 75 mole percent SiO₂The glass contains 1mol percent to 4mol percent of Na in terms of mol percent₂O，Na₂O and Li₂The total amount of O is less than 12 mol%.

7. The glass for chemical strengthening and low dielectric constant of claim 6, wherein the glass comprises 69 to 75 mol% SiO in terms of mole percent₂1.5 to 3mol percent of Na₂O，Na₂O+Li₂Of OThe content is 2-12 mol%.

8. The low dielectric constant glass for chemical strengthening of claim 7, wherein Na is₂O+Li₂The content of O is 3-10 mol%.

9. The low dielectric constant glass useful for chemical strengthening of claim 7, wherein SiO is₂+Al₂O₃The content of (B) is not less than 80 mol%.

10. The chemically strengthened low dielectric constant glass according to any one of claims 1-9, wherein the glass further comprises P ₂O₅、B₂O₃、MgO、SnO₂、ZrO₂、TiO₂The mol percentage of the massage is as follows: p₂O₅+B₂O₃1 to 5 mol% of (A), 1 to 7.5 mol% of MgO, and SnO₂The content of (b) is 0.1-2 mol%, ZrO₂0 to 5 mol% of TiO₂The content of (B) is 0 to 5 mol%.

11. The glass with low dielectric constant for chemical strengthening according to claim 10, wherein the glass contains 0 to 80 wt% of uniformly distributed grains, and the grain size of the grains is 150nm or less; the crystal grains with the grain diameter of 7-20 nm account for more than 60% of the total crystal quantity.

12. The glass with low dielectric constant for chemical strengthening of claim 10, wherein the glass has a melting temperature of 1630 ℃ to 1700 ℃, a thickness of 0.2 mm to 2mm, a young's modulus of at least 78Gpa, a vickers hardness of at least 630kgf/mm 2; the glass can be prepared by an overflow downdraw method, a float method or a rolling method.

13. A strengthened glass, wherein the chemically strengthened glass is prepared by chemically strengthening the glass of any one of claims 1 to 10 in a mixed salt bath for one or more times; the tempered glass is internally provided with a tensile stress layer, the tensile stress layer is provided with an upper boundary which is at a certain interval with the upper surface of the tempered glass and a lower boundary which is at a certain interval with the lower surface of the tempered glass, a curve which is drawn by taking the tensile stress in the tensile stress layer, is perpendicular to the upper boundary and the lower boundary, and the upper end point and the lower end point of the curve respectively fall on certain points on line segments on the upper boundary and the lower boundary as a Y axis, and the distance between the corresponding points and the upper boundary as an X axis is taken as a tensile stress curve, the ratio of the fixed integral of the tensile stress curve to the thickness of the tempered glass is taken as the tensile stress linear density, and the tensile stress linear density of the tempered glass is greater than or equal to 40000 MPa/mm.

14. The strengthened glass of claim 13, wherein the strengthened glass is free of a mark band at an immediately fractured fracture section when the linear density of tensile stress is at or below a safety threshold of at least 45000 Mpa/mm.

15. The tempered glass of claim 13, wherein the mixed salt bath comprises one or more of potassium nitrate, sodium nitrate, and lithium nitrate, and wherein the temperature of the mixed salt bath is 390-550 ℃.

16. The strengthened glass of any one of claims 13-15, wherein the strengthened glass has a surface compressive stress CS of at least 600Mpa, a compressive stress depth DOL of at least 16% of its thickness, and a sand impact height of at least 1.0 m.

Technical Field

The invention relates to the technical field of glass, in particular to glass with low dielectric constant and tempered glass which can be used for chemical tempering.

Background

At present, glass is commonly used as a front cover and a rear cover protection material of electronic equipment (such as a smart phone, a portable computer, a tablet computer and the like). In the case of a smartphone, which has an electronic system operating at high or ultra-high frequencies, the glass absorbs at least a portion of the energy and converts the absorbed energy into heat when exposed to such high or ultra-high frequency electromagnetic fields, and this energy in the form of heat absorbed by the glass is referred to as dielectric loss energy. The dielectric loss energy is proportional to the "dielectric constant" and the "dielectric loss tangent" of the glass composition, as shown by the following expressions: w is kfv2 (tan). Where "W" is the dielectric loss energy in the glass, "k" is a constant, "f" is the frequency, "v 2" is the potential gradient, "" is the dielectric constant, "tan" is the dielectric loss tangent. As shown in the above expression, the dielectric loss energy "W" increases with an increase in the dielectric constant and dielectric loss tangent of the glass and/or an increase in the frequency. That is, the larger the dielectric constant of the glass is, the larger the dielectric loss energy is, the more unfavorable the signal transmission is, and the phenomena of the signal transmission speed reduction, the signal intensity attenuation, the signal transmission time delay and the like will be more serious. In the 5G era, the phenomena of slow signal transmission speed, signal strength attenuation and signal transmission time delay are not allowed. It has been found that the dielectric constant of the glass used for ion exchange is generally large, which is closely related to the degree of densification of the network structure and the content of active metal ions in the glass. That is, to lower the dielectric constant of the glass, it is necessary to control the content of active metal ions in the glass and to increase the densification of the glass network. On the other hand, as a protective material of the smart phone, the selected glass also has high mechanical strength, the conventional method is improved by ion exchange, and the implementation of the ion exchange requires that the glass contains enough active alkali metal ions. Due to the existence of this contradiction, it has been difficult to obtain a glass having high mechanical strength and a small dielectric constant.

Disclosure of Invention

The technical problem to be solved by the present invention is to provide a glass with low dielectric constant for chemical strengthening, which can be used for chemical strengthening to obtain a strengthened glass with high mechanical strength and low dielectric constant, and the strengthened glass is very suitable for devices on communication terminals under 5G communication system.

The technical scheme adopted by the invention for solving the technical problems is as follows: the glass has a dielectric constant of 4.8-6.5 and a dielectric loss tangent of less than or equal to 3 x 10 at room temperature and a frequency of 50GHz after chemical strengthening^-2Said glass comprising SiO₂、Al₂O₃、Na₂O, wherein, in mol percent, Na₂O content of 1-6 mol%, SiO₂+Al₂O₃The content of (B) is not less than 78 mol%.

Further, the glass has a dielectric constant of 4.8-6.5 and a dielectric loss tangent of less than or equal to 2 x 10 at room temperature and a frequency of 20GHz after chemical strengthening^-2。

Further, the glass has a dielectric constant of 4.8-6.5 and a dielectric loss tangent of less than or equal to 8 x 10 at room temperature and a frequency of 2GHz after chemical strengthening^-3。

Further, the glass has a dielectric constant of 4.8-6.5 and a dielectric loss tangent of less than or equal to 5 x 10 at room temperature and a frequency of 5000MHz after chemical strengthening ^-3。

Further, the glass has a dielectric constant of 4.8-6.5 and a dielectric loss tangent of less than or equal to 3 x 10 at room temperature and 3000MHz after chemical strengthening^-3。

As a preference of the glass with low dielectric constant for chemical strengthening of the present invention, the glass contains 65 to 75 mol% of SiO in terms of mol% is used₂The glass contains 1-4 mol% of Na in terms of mol percentage₂O，Na₂O and Li₂The total amount of O is less than 12 mol%. More preferably, the glass comprises 69 to 75 mol% SiO in terms of mole percent₂1.5 to 3 mol% of Na₂O，Na₂O+Li₂The content of O is 2-12 mol%.

As another preferable low dielectric constant glass usable for chemical strengthening of the present invention, Na₂O+Li₂The content of O is 3-10 mol%.

As still another preferable low dielectric constant glass for chemical strengthening of the present invention, SiO₂+Al₂O₃The content of (B) is not less than 80 mol%.

As still another preferable low dielectric constant glass usable for chemical strengthening of the present invention, the glass further contains P₂O₅、B₂O₃、MgO、SnO₂、ZrO₂、TiO₂The mol percentage of the massage is as follows: p₂O₅+B₂O₃1 to 5 mol% of (A), 1 to 7.5 mol% of MgO, and SnO₂The content of (b) is 0.1-2 mol%, ZrO₂0 to 5 mol% of TiO ₂The content of (B) is 0 to 5 mol%. More preferably, the glass contains 0-80 wt% of uniformly distributed crystal grains, and the grain diameter of the crystal grains is less than or equal to 150 nm; the crystal grains with the grain diameter of 7-20 nm account for more than 60% of the total crystal quantity.

As still another preferred low dielectric constant glass for chemical strengthening of the present invention, the glass contains 2 to 4% by mole of B₂O₃. More preferably, the melting temperature of the glass is 1630-1700 ℃, the thickness is 0.2-2 mm, and the Young modulus is at least 78 Gpa; the glass is prepared by adopting an overflow downdraw method, a float method or a rolling method.

The invention also provides a strengthened glass, which is prepared by chemically strengthening the glass in the mixed salt bath for one or more times, the tempered glass is internally provided with a tensile stress layer, the tensile stress layer is provided with an upper boundary which is at a certain interval with the upper surface of the tempered glass and a lower boundary which is at a certain interval with the lower surface of the tempered glass, a curve which is drawn by taking the tensile stress in the tensile stress layer, which is perpendicular to the upper boundary and the lower boundary at the same time, and the upper end point and the lower end point of which respectively fall on a certain point on a line segment on the upper boundary and the lower boundary as a Y axis and the distance between the corresponding point and the upper boundary as an X axis is taken as a tensile stress curve, and the ratio of the fixed integral of the tensile stress curve and the thickness of the tempered glass is taken as the tensile stress linear density, the tensile stress linear density of the tempered glass is greater than or equal to 40000 MPa/mm.

Further, the tempered glass has no trace band on a fracture section which is immediately fractured when the tensile stress linear density is less than or equal to a safety threshold value, and the safety threshold value is at least 45000 MPa/mm.

Preferably, the mixed salt bath contains one or more of potassium nitrate, sodium nitrate and lithium nitrate, and the temperature of the mixed salt bath is 390 to 550 ℃.

As another preferred aspect of the strengthened glass of the present invention, the strengthened glass has a compressive stress CS of at least 600MPa on the surface, a depth DOL of compressive stress of at least 16% of its own thickness, and a Vickers hardness of at least 630kgf/mm²。

The glass provided by the invention can achieve the following beneficial effects: in the glass, the glass network constituent is mainly SiO₂And Al₂O₃The high silicon high aluminum network structure composition can increase the amount of internal bridge oxygen of the glass, especially SiO₂The higher the content of (A), the more advantageous is the reduction in the dielectric constant of the glass. In addition, the low content of alkali metal components ensures that the glass can be subjected to ion exchange in a salt bath to obtain strengthened glass with higher strength, and simultaneously, the content of alkali metal ions in a glass network is less, so that the reduction of the dielectric constant is facilitated.

Drawings

FIG. 1 is a scanning electron micrograph of glass provided in example 5 of the present invention;

FIG. 2 is a scanning electron micrograph of glass provided in example 6 of the present invention.

Detailed Description

The glass of the present invention can be prepared by the following steps:

s1, mixing the following raw materials in percentage by mole: 65-72% of SiO₂10 to 16% of Al₂O₃1.7-6% of Na₂O, 4.5-8% of Li₂O, 0-2.5% of P₂O₅2-5% of B₂O₃2 to 4.7% of MgO and 0.3 to 0.5% of SnO₂0 to 1% of ZrO₂And 0 to 1% of TiO₂；

S2, preserving the temperature of the mixed raw materials at 1630-1700 ℃ for 2-4 h to form glass liquid, and pouring the glass liquid into a mold for molding to obtain a flaky intermediate product with the thickness of 0.2-2 mm;

and S3, transferring the intermediate product into a muffle furnace at the temperature of 450 ℃, and naturally cooling and annealing to obtain the glass.

Of course, the glass of the present invention can also be produced by the overflow downdraw process, the float process or the rolling process commonly used in the art using the raw material formulation as shown above.

The glass of the invention is detected by adopting a detection method which is general in the industry, and the performance is found as follows: the glass contains 0-50 wt% of uniformly distributed crystal grains, and the size of the crystal grains is 40-170 nm. The glass of the present invention has a Young's modulus of at least 78GPa and a Vickers hardness of at least 630kgf/mm ²。

The tempered glass of the present invention is produced by chemically tempering the glass of the present invention in a mixed salt bath. The adopted mixed salt bath contains one or more of potassium nitrate, sodium nitrate and lithium nitrate, and the temperature of the mixed salt bath is 390-550 ℃.

The performance detection of the tempered glass is carried out by adopting a detection method which is general in the industry, and the following results are found: the tempered glass is internally provided with a tensile stress layer, the tensile stress layer is provided with an upper boundary which is at a certain interval with the upper surface of the tempered glass and a lower boundary which is at a certain interval with the lower surface of the tempered glass, a curve which is drawn by taking the tensile stress in the tensile stress layer, is perpendicular to the upper boundary and the lower boundary, and the upper end point and the lower end point of the curve respectively fall on certain points on line segments on the upper boundary and the lower boundary as a Y axis, and the distance between the corresponding points and the upper boundary as an X axis is taken as a tensile stress curve, the ratio of the fixed integral of the tensile stress curve to the thickness of the tempered glass is taken as the tensile stress linear density, and the tensile stress linear density of the tempered glass is greater than or equal to 40000 MPa/mm. And when the tensile stress linear density is less than or equal to a safety threshold value, the tempered glass has no trace band on a fracture section which is immediately fractured, and the safety threshold value is at least 45000 Mpa/mm. It should be explained that the calculation process of the constant integral of the tensile stress curve is to firstly measure the tensile stress magnitude at least at 10 equally spaced positions on the line segment by using the scattered light SLP-2000 stress gauge, then to fit the tensile stress curve, and then to calculate the constant integral of the tensile stress curve. The immediate fracture is realized by adopting a pneumatic transmission Vickers hardness pressure head to impact the surface of the glass at a constant force and a constant speed, so that a breaking point is formed on the surface of the glass, and when only 2-4 cracks are generated at the breaking point, the immediate fracture is realized. When the glass is immediately broken, the tensile stress in the glass causes the crack of the glass to be expanded, so that the damage condition of the tensile stress to the internal structure of the glass can be reflected. The striae refer to the black lines observable by an electron microscope on the section immediately after fracture of the glass with the tensile stress linear density greater than the safety threshold.

The performance detection of the tempered glass is carried out by adopting a detection method which is general in the industry, and the following results are found: the surface compressive stress CS of the tempered glass is at least 600Mpa, the compressive stress depth DOL is at least 16% of the thickness of the tempered glass, and the sand impact resistance height is at least 1.0 mm.

The depth of compressive stress and the internal tensile stress of the tempered glass were measured by using a waveguide optical stress meter FSM-6000LE and a scattered light SLP-2000 stress meter manufactured by orihua corporation, japan, respectively.

It should be explained that the sand impact height detection process is as follows: cutting the glass into small pieces of 50 x 50mm, fixing the small pieces on a marble plate by using an adhesive tape, preparing a weight block with the weight of 170g and the size of 150 x 67 x 7mm, sticking 180-mesh abrasive paper on one surface of the weight block, freely dropping the weight block from the height of 0.3mm in a manner that the weight block faces downwards with the abrasive paper so that the surface of the abrasive paper impacts the glass, observing the state of the glass, if the glass is intact, increasing the height by 10cm, then dropping again, and taking the highest unbroken point as the impact height of the sand resistant surface.

The above-mentioned chemical agents are all commercially available products.

For a more clear understanding of the technical features, objects and effects of the present invention, embodiments of the present invention will now be described in detail with reference to the accompanying drawings. It is to be understood that the described embodiments are merely exemplary of the invention, and not restrictive of the full scope of the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.