WO2018090184A1 - Glass substrate for chemical strengthening having a low softening point and being easily thermoformed, and preparation method therefor - Google Patents

Abstract

A glass substrate for chemical strengthening having a low softening point and being easily thermoformed. The glass substrate for chemical strengthening has a softening point lower than 900℃ and comprises backbone components and auxiliary components. The backbone components comprise SiO₂, Al₂O₃, Bi₂O₃ and P₂O₅, and the auxiliary components comprise alkali metal oxides; the components in the glass for chemical strengthening in mole percentage are 50-70% of SiO₂, 5-17% of Al₂O₃, 0.1-15% of Bi₂O₃, and 0.1-10% of P₂O₅, the molar percentages of Bi₂O₃ and P₂O₅ totaling 2.5-22%, and 5-25% of the alkali metal oxides. The glass for chemical strengthening is a non-As material.

Description

Glass substrate for chemical strengthening with low softening point and easy thermoforming and preparation method thereof Technical field

The present invention relates to a glass material, and more particularly to a glass substrate for chemical strengthening which has a low softening point and is easily thermoformed, and a method for preparing the same.

Background technique

Today's glass manufacturers in the world are developing new technologies for energy, environmental protection, information, and biology. With the continuous development of the world's high-tech industry, the demand for ultra-thin glass in the international market is increasing, especially for ultra-thin glass substrates for flat panel displays and mobile phones. Display Search predicts that the demand for ultra-thin glass substrates for flat panel displays will grow at an average rate of 20% per year in the market. Flat panel displays require light weight, small size, and portability, making ultra-thin glass an indispensable substrate material. The so-called ultra-thin glass is relative to the thickness of ordinary flat glass. Generally, the thickness is less than 3 mm, which is thin glass, and the thickness is less than 1.5 mm, which is called ultra-thin glass. On the other hand, Display Search predicts that flexible displays will become the new mainstream and growth point, and the shaped reinforced glass cover matched with flexible display will also become a huge new demand.

However, the obvious drawback of ultra-thinness is the decrease in mechanical strength. While reducing weight and volume, impurities, defects, and any negative factors that reduce the strength of the glass are amplified. For example, a small crack or defect is only a negligible flaw on a normal thickness glass, but the same size crack may have penetrated into the glass compared to ultra-thin glass, which cannot be ignored. damage. This directly causes the ultra-thin glass to lag significantly behind ordinary flat glass in mechanical properties such as flexural strength and surface hardness, which brings great obstacles to the practical application of ultra-thin glass. On the other hand, with the development of flexible display, the market demand for shaped glass has increased, and the shaped glass can only be used in the post-process hot forming process, and the softening point of the high-alumina tempered glass substrate commonly used in the market is usually Above 910 degrees Celsius, the softening point is too high to be easily formed by hot forming, and the forming mold is extremely easy to be damaged at a high temperature, and the metal parts in the forming apparatus are easily deformed by deformation at a temperature of 900 ° C or higher.

Therefore, a glass substrate for chemical strengthening, which has a low softening point and is easy to be thermoformed, and which is ultra-thin and high-strength, is an urgent problem to be solved.

Summary of the invention

Accordingly, the present invention has been made in an effort to provide a glass substrate for chemical strengthening which has a low softening point and is easily thermoformed, and a method for producing the same.

A glass substrate for chemical strengthening having a low softening point and being easily thermoformed, the glass substrate for chemical strengthening having a softening point of less than 900 ° C, comprising a backbone component and an auxiliary component, the backbone component comprising SiO ₂ , Al ₂ O ₃ , Bi ₂ O ₃ , P ₂ O ₅ , the auxiliary component includes an alkali metal oxide, and SiO ₂ accounts for the mole percentage of each component in the chemical strengthening glass. 50% to 70%, Al ₂ O ₃ accounts for 5% to 17%, Bi ₂ O ₃ accounts for 0.1% to 15%, P ₂ O ₅ accounts for 0.1% to 10%, and the Bi ₂ O ₃ and P ₂ O ₅ The molar percentage of the total is 2.5% to 22%, the alkali metal oxide is 5% to 25%, and the glass for chemical strengthening is a non-As material.

Alternatively, the low softening point, thermoforming susceptible to chemical strengthening of a glass substrate with a softening point below 880 deg.] C, the parts of the backbone of the group of Bi ₂ O ₃ molar fraction of 0.1% to 5%, The molar percentage of P ₂ O ₅ is from 0.1% to 3.5%, and the molar percentage of the total of Bi ₂ O ₃ and P ₂ O ₅ is from 2.5% to 8.5%. .

Optionally, the low softening point, the glass substrate for chemical strengthening which is easy to thermoform has a softening point of less than 860 ° C, and the molar percentage of Bi ₂ O ₃ in the backbone component is 0.1% to 5%. The molar percentage of P ₂ O ₅ is more than 3.5% and less than or equal to 5%, and the molar percentage of the total of Bi ₂ O ₃ and P ₂ O ₅ is 3.6% to 10%.

Optionally, the low softening point, the glass substrate for chemical strengthening which is easy to thermoform has a softening point of less than 840 ° C, and the molar percentage of Bi ₂ O ₃ in the backbone component is 0.1% to 5%. The molar percentage of P ₂ O ₅ is more than 5% and less than or equal to 10%, and the molar percentage of the total of Bi ₂ O ₃ and P ₂ O ₅ is 5.1% to 15%.

Optionally, the low softening point, the glass substrate for chemical strengthening which is easy to thermoform has a softening point of less than 800 ° C, and the molar percentage of Bi ₂ O ₃ in the backbone component is greater than 7% and less than 15%. The molar percentage of P ₂ O ₅ is from 0.1% to 10%, and the molar percentage of the total of Bi ₂ O ₃ and P ₂ O ₅ is from 7.1% to 22%.

Based on the above four conditions (i.e., Bi ₂ O ₃ and P ₂ O _{5 in} different content ranges) components and their contents, if the low softening point, the thermoforming glass substrate for chemical strengthening is reintroduced into Li ₂ O, and at the low softening point, in the glass substrate for chemical strengthening which is easy to be thermoformed, the ratio of other alkali metal oxides does not move, and when the molar percentage of Li ₂ O exceeds 7%, it increases by 1%, The softening point of the glass substrate for chemical strengthening which is easy to be thermoformed at the low softening point is about 20 degrees Celsius lower than the softening point temperature in the four cases. The introduction of Li ₂ O provides a smaller ion for the post-processing chemically enhanced ion exchange of the glass, which can produce greater surface compressive stress and stress layer depth after chemical strengthening, thereby also increasing the impact strength of the chemically strengthened glass.

Optionally, the alkali metal oxide is at least one of K ₂ O, Na ₂ O, and Li ₂ O; wherein the molar percentage of K ₂ O is not more than 5%, Na ₂ O or Li ₂ O The molar percentage is not more than 23.5%; when both Na ₂ O and Li ₂ O are contained, Na ₂ O accounts for 2.5% to 21%, and Li ₂ O accounts for 5% to 18%.

Optionally, the alkali metal oxide comprises Na ₂ O and Li ₂ O, in terms of the mole percentage of each component at a low softening point, a glass substrate for chemical strengthening which is easily thermoformed, Na ₂ O It accounts for 2.5% to 21% and Li ₂ O accounts for 5% to 18%.

Optionally, the alkali metal oxide comprises Na ₂ O, Li ₂ O and K ₂ O, and the mole percentage of each component in the glass substrate for chemical strengthening which is easy to thermoform at the low softening point As a content, Na ₂ O accounts for 2.5% to 21%, Li ₂ O accounts for 5% to 18%, and K ₂ O accounts for 0.1% to 5%.

Optionally, the auxiliary component further comprises an alkaline earth metal oxide, wherein the alkaline earth metal oxide is at least one of CaO and MgO, and the mole percentage of each component in the glass for chemical strengthening The content of CaO does not exceed 5%, and MgO does not exceed 7%.

Optionally, the auxiliary component further comprises 0% to 5% by mole of B ₂ O ₃ and 0% to 5% of Sb ₂ O ₃ .

A method for preparing a glass substrate for chemical strengthening which has a low softening point and is easy to be thermoformed, and comprises the following steps:

Providing the low-softening point, the raw material corresponding to the composition of the glass substrate for chemical strengthening which is easy to thermoform, and the mole percentage of each component in the glass substrate for chemical strengthening which is easy to be thermoformed according to the finally obtained low softening point The ratio of the above raw materials is set to be mixed, and the mixture is placed in a crucible and stirred uniformly;

Adding at 1400-1630 ° C to melt the mixture, clarifying to obtain a molten glass liquid;

The molten glass liquid is subjected to a forming treatment, and is slowly cooled and then annealed to obtain the glass substrate for chemical strengthening which is low in softening point and which is easily thermoformed.

The method for forming the molten glass liquid comprises the following steps: 1) pouring the molten glass liquid into a stainless steel metal mold for casting; 2) or introducing the molten glass liquid into the tin bath through the glass The two sides are drawn into flat glass; 3) or the molten glass liquid is introduced into the wedge forming block with the upper side and the upper side, so that the molten glass naturally overflows on the front and back sides of the forming block while vertically pulling Made of flat glass.

Compared with the prior art, the present invention has the following advantages:

First, the present invention is a low softening point, thermoforming susceptible to chemical strengthening glass substrate selection of _{SiO 2, Al 2 O 3,} Bi 2 O 3, P 2 O 5 these four components in a specific composition ratio of a stable network structure Large backbone structure, and does not contain As ₂ O ₃ material; this main backbone structure makes the glass material have strong ion exchange channels during chemical strengthening, resulting in large compressive stress and greater The depth of ion exchange. That is, the depth of the compressive stress layer achieved by ion exchange is more than double that of the ordinary aluminosilicate glass which does not contain the backbone structure in the same ion exchange salt bath, and is a normal sodium which does not contain the backbone structure. More than twice as much as calcium silicate glass.

Secondly, the glass substrate for chemical strengthening of the low-softening point and the easy thermoforming of the present invention has a low softening point and is easy to be thermoformed due to its composition and composition content, and its softening point is according to Bi ₂ O. ₃ , P ₂ O ₅ different content of the composition can be as low as 880 ° C, 860 ° C, 840 ° C, 800 ° C, such a chemical strengthening glass substrate, through the subsequent chemical strengthening process can produce ultra-high strength ultra-thin glass Substrate, which has a low softening point and is easy to be thermoformed, and is very suitable for thermoforming of non-planar glass (ie, shaped glass) for the preparation of curved electronic devices, such as mobile communication or information equipment housings. The surface structure of the body or screen, etc.

detailed description

The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It is understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

The glass substrate for chemical strengthening which is low in softening point and which is easy to be thermoformed by the present invention can produce an ultra-high-strength ultra-thin glass substrate after chemical strengthening (ion exchange), which has a low softening point and is easy to be obtained. The thermoforming property is very suitable for the thermoforming of non-planar glass (shaped glass), and is suitable for the preparation of curved electronic devices, such as mobile communication or the surface structure of the information device housing or screen.

The "glass substrate for chemical strengthening" as used in the present specification means glass before chemical strengthening treatment, and the "chemically strengthened glass substrate" means glass which can form a compressive stress layer on the surface by a chemical strengthening treatment process.

The glass substrate for chemical strengthening of the low-softening point and the thermoforming which is easy to be thermoformed as the glass substrate material for chemical strengthening treatment requires rapid and efficient ion exchange during chemical strengthening, so that the network structure of the glass becomes good or bad. The first condition is that a relatively stable backbone structure with a large network structure is necessary.

Therefore, the glass substrate for chemical strengthening of the low softening point and the easy thermoforming of the present invention has a backbone structure of a large network structure, and has a high ion which can be exchanged, so that it can be produced in the latter stage of ion exchange strengthening. Large compressive stress and compressive stress depth increase the strength of the glass. The backbone structure consists of SiO ₂ , Al ₂ O ₃ , Bi ₂ O ₃ , and P ₂ O ₅ , which constitute a larger backbone structure, which facilitates ion exchange in the latter stage. However, the amount of phosphorus and antimony needs reasonable control. First, the introduction of phosphorus oxide can lower the softening point of the glass. However, after the introduction of too much phosphorus oxide, the chemical stability of the glass is not good, and the glass is easily corroded and weathered, so the amount of phosphorus is A key point; secondly, the purpose of introducing yttrium oxide is to maintain a large glass backbone structure and further reduce the softening point of the glass, but the weight of yttrium oxide is large, too much is not suitable, so the amount of bismuth is also a key point. The composition of the glass substrate for chemical strengthening of the low softening point and the easy thermoforming of the present invention has been verified by a large number of industrial experiments, and is summarized as follows.

A glass substrate for chemical strengthening having a low softening point and being easily thermoformed, the glass substrate for chemical strengthening having a softening point of less than 900 ° C, the glass substrate for chemical strengthening comprising a backbone component and an auxiliary component, and the backbone component comprises SiO ₂ , Al ₂ O ₃ , Bi ₂ O ₃ , P ₂ O ₅ , the auxiliary component includes an alkali metal oxide and an alkaline earth metal oxide, and the moles of each component in the chemical strengthening glass content of points, SiO ₂ accounted for _{50% ~ 70%, Al 2} O 3 accounts for _{5% ~ 17%, Bi 2} O 3 account for _{0.1% ~ 15%, P 2} O 5 0.1% - 10%, the Bi ₂ The molar percentage of the sum of O ₃ and P ₂ O ₅ is 2.5% to 22%, the alkali metal oxide is 5% to 25%, and the glass for chemical strengthening is a non-As material.

SiO ₂ is a component constituting a glass skeleton and is an essential component. If it is less than 50%, the stability of the glass or the subsequent reduction of the milk may be lowered. If the viscosity of the glass is higher than 80%, the meltability is lowered, and in the present invention, the SiO ₂ content is controlled in the range of 50% to 70%.

Al ₂ O ₃ is introduced into the backbone of the network structure can be increased, the glass may be enhanced ion exchange property, and having improved heat stability, weather resistance, the effect of the Young's modulus, but too much will lead to the introduction of the viscosity of the glass melt increases Smelting is more difficult.

The introduction of P ₂ O ₅ can increase the backbone network structure, enhance the ion exchangeability of the glass, and can advantageously increase the strain point and have a good influence on the melting temperature, but excessive introduction will reduce chemical durability and uniformity. .

The introduction of Bi ₂ O ₃ can increase the backbone network structure, enhance the ion exchangeability of the glass, and greatly reduce the melting temperature, but excessive introduction will change the color of the glass, which will reduce the chemical stability.

As a glass substrate material for chemical strengthening treatment, in addition to network structure considerations, it is necessary to introduce a component which is easily exchanged by larger ions to generate a large compressive stress, such as an alkali metal oxide. The alkali metal oxide accounts for 5% to 25% by mole of the chemical strengthening glass, preferably containing The amount is 5% to 18.5%.

Na ₂ O is introduced because Na ions are materials which are mainly substituted with potassium ions in monovalent ion exchange treatment, and also exist as fluxes. For controlling the thermal expansion coefficient, the high temperature viscosity of the glass is lowered to improve the meltability and formability. Helpful, but when introduced too much, it will reduce the chemical resistance of the glass.

Li ₂ O is introduced because Li ions are smaller than Na ions and are materials which are mainly replaced by sodium and potassium ions in ion exchange treatment. By using ion exchange to generate larger surface compressive stress, it is possible to control thermal expansion as a flux. The coefficient lowers the high-temperature viscosity of the glass to improve the meltability and formability, and lowers the softening temperature of the glass. However, when the amount is too large, a tendency to crystallize occurs, and surface defects are more likely to occur during the heat treatment.

Meltability and formability, and can reduce the incidence of cracks K ₂ O can lower the high temperature viscosity of the glass, thereby increasing glass. In addition, it is also a component that improves the crystallization property.

Optionally, the alkali metal oxide is at least one of K ₂ O, Na ₂ O, and Li ₂ O; wherein the molar percentage of K ₂ O is not more than 5%, Na ₂ O or Li ₂ O The molar percentage is not more than 23.5%; when both Na ₂ O and Li ₂ O are contained, Na ₂ O accounts for 2.5% to 21%, and Li ₂ O accounts for 5% to 18%.

Optionally, the alkali metal oxide comprises Na ₂ O and Li ₂ O, in terms of the mole percentage of each component at a low softening point, a glass substrate for chemical strengthening which is easily thermoformed, Na ₂ O It accounts for 2.5% to 21% and Li ₂ O accounts for 5% to 18%.

Optionally, the alkali metal oxide comprises Na ₂ O, Li ₂ O and K ₂ O, and the mole percentage of each component in the glass substrate for chemical strengthening which is easy to thermoform at the low softening point As a content, Na ₂ O accounts for 2.5% to 21%, Li ₂ O accounts for 5% to 18%, and K ₂ O accounts for 0.1% to 5%.

Considering the divalent ion exchange of the supplementary means and the other properties of the glass, it is also conceivable to introduce an alkaline earth metal oxide, but the introduction amount cannot be too high, otherwise the monovalent ion exchange efficiency will be affected. The alkaline earth metal oxide accounts for 0% to 10% by mole of the glass substrate for chemical strengthening which is easy to be thermoformed at the low softening point, and the alkaline earth metal oxide includes MgO and CaO.

The introduction of MgO can increase the surface hardness, a component which is less likely to cause scratches and which improves the meltability of the glass. It can lower the viscosity of the glass, thereby improving the meltability and the malleability, and thus the strain point and Young's modulus.

CaO also lowers the viscosity of the glass, thereby improving the meltability and die forgeability, and thus the strain point and Young's modulus. Accordingly, CaO can improve the devitrification resistance of the glass.

The alkaline earth metal oxide is MgO or CaO, and the molar percentage of the MgO or CaO in the glass substrate for chemical strengthening which is easy to be thermoformed at the low softening point is 0.1% to 8.5%.

The alkaline earth metal oxides are CaO and MgO, and CaO accounts for 0% to 5%, MgO, based on the mole percentage of each component at the low softening point and the glass substrate for chemical strengthening which is easy to thermoform. It accounts for 0.1% to 7%.

In addition to the above components, the glass substrate for chemical strengthening of the present invention having a low softening point and easy thermoforming may further include other components such as B ₂ O ₃ , Sb ₂ O ₃ , ZrO ₂ , TiO ₂ , SnO ₂ .

ZrO ₂ and TiO ₂ can improve the ion exchange rate, improve the chemical stability of the glass, increase the viscosity, hardness, and lower the coefficient of thermal expansion, and are sometimes preferably contained.

Sb ₂ O ₃ and SnO ₂ may be used singly or as a clarifying agent alone or in combination.

Preferably, the other oxide in the glass substrate for chemical strengthening which is low in softening point and which is easy to thermoform comprises B ₂ O _{3 in a} molar percentage of 0% to 5%.

Preferably, the other oxide in the glass substrate for chemical strengthening which is low in softening point and which is easy to thermoform comprises Sb ₂ O _{3 in a} molar percentage of 0% to 5%.

In order to obtain a glass substrate for chemical strengthening having different softening points, the content of Bi ₂ O ₃ and P ₂ O ₅ in the backbone component can be adjusted, for example, the content range of the Bi ₂ O ₃ is fixed, and the content range of the P ₂ O ₅ is adjusted. And adjusting the content range of the sum of Bi ₂ O ₃ and P ₂ O ₅ so that the glass substrate for chemical strengthening reaches different softening points. Three scenarios are given below:

(1) If it is desired to make the softening point of the glass substrate for chemical strengthening lower than 880 ° C, the molar percentage of Bi ₂ O ₃ in the backbone component is 0.1% to 5%, and the molar ratio of P ₂ O ₅ The content of the fraction is more than 0.1% and less than 3.5%, and the molar percentage of the total of Bi ₂ O ₃ and P ₂ O ₅ is more than 2.5% and less than 8.5%.

(2) If it is desired to make the softening point of the glass substrate for chemical strengthening lower than 860 ° C, the molar percentage of Bi ₂ O ₃ in the backbone component is 0.1% to 5%, and the molar ratio of P ₂ O ₅ The content of the fraction is more than 3.5% and less than 5%, and the molar percentage of the total of Bi ₂ O ₃ and P ₂ O ₅ is more than 3.6% and less than 10%.

(3) If it is desired to make the softening point of the glass substrate for chemical strengthening lower than 840 ° C, the molar percentage of Bi ₂ O ₃ in the backbone component is 0.1% to 5%, and the molar ratio of P ₂ O ₅ The content of the fraction is more than 5% and less than 10%, and the molar percentage of the total of Bi ₂ O ₃ and P ₂ O ₅ is more than 5.1% and less than 15%.

(3) If it is desired to make the softening point of the glass substrate for chemical strengthening lower than 800 ° C, the molar percentage of Bi ₂ O ₃ in the backbone component is more than 7% and less than 15%, and the mole of P ₂ O ₅ The percentage is from 0.1% to 10%, and the molar percentage of the total of Bi ₂ O ₃ and P ₂ O ₅ is from 7.1% to 22%.

In the above four cases (i.e., Bi ₂ O ₃ and P ₂ O _{5 are in} different content ranges), if the low softening point, the glass substrate for chemical strengthening is easy to be thermoformed, Li ₂ O is reintroduced, and a low softening point, a ratio of other alkali metal oxides in a glass substrate for chemical strengthening which is easy to thermoform, and a low softening point, when the molar percentage of Li ₂ O exceeds 7%, for every 1% increase The softening point of the glass substrate for chemical strengthening which is easy to thermoform is about 20 degrees Celsius lower than the softening point temperature in the four cases. The introduction of Li ₂ O provides a smaller ion for the post-processing chemically enhanced ion exchange of the glass, which can produce greater surface compressive stress and stress layer depth after chemical strengthening, thereby also increasing the impact strength of the chemically strengthened glass.

In addition, the present invention also provides a method for preparing a glass substrate for chemical strengthening which has a low softening point and is easily thermoformed, and includes the following steps:

Providing the low-softening point, the raw material corresponding to the composition of the glass substrate for chemical strengthening which is easy to thermoform, and the mole percentage of each component in the glass substrate for chemical strengthening which is easy to be thermoformed according to the finally obtained low softening point The mixture of the above raw materials is set to be proportioned, the mixture is placed in a crucible, and the mixture is uniformly stirred; the backbone component includes SiO ₂ , Al ₂ O ₃ , Bi ₂ O ₃ , P ₂ O ₅ , and the auxiliary component includes a base. Metal oxides and alkaline earth metal oxides, SiO ₂ accounts for 50% to 70%, and Al ₂ O ₃ accounts for 5% to 17% by mole of the components in the chemical strengthening glass substrate. , Bi ₂ O ₃ accounts for 0.1% to 15%, P ₂ O ₅ accounts for 0.1% to 10%, and the molar percentage of the total of Bi ₂ O ₃ and P ₂ O ₅ is 2.5% to 22%. The metal oxide accounts for 5% to 25%, and the chemical strengthening glass is a non-As material;

Heating at 1400 ° C to 1630 ° C to melt the mixture to obtain a molten glass liquid;

The molten glass liquid is subjected to a forming treatment, and is slowly cooled and then annealed to obtain the glass substrate for chemical strengthening which is low in softening point and which is easily thermoformed.

Forming the molten glass solution comprises the following steps: 1) pouring the molten glass liquid into a stainless steel metal mold for casting; 2) or introducing the molten glass liquid into the tin bath, through Drawing the two sides of the glass into flat glass; 3) or introducing the molten glass liquid onto the wedge-shaped block whose side is upper and lower, so that the molten glass naturally overflows on the front and back sides of the forming block, while simultaneously Vertically drawn into flat glass.

Optionally, the alkali metal oxide is at least one of K ₂ O, Na ₂ O, and Li ₂ O; wherein the molar percentage of K ₂ O is not more than 5%, Na ₂ O or Li ₂ O The molar percentage is not more than 23.5%; when both Na ₂ O and Li ₂ O are contained, Na ₂ O accounts for 2.5% to 21%, and Li ₂ O accounts for 5% to 18%.

Optionally, the alkali metal oxide comprises Na ₂ O and Li ₂ O, in terms of the mole percentage of each component at a low softening point, a glass substrate for chemical strengthening which is easily thermoformed, Na ₂ O It accounts for 2.5% to 21% and Li ₂ O accounts for 5% to 18%.

Optionally, the alkali metal oxide comprises Na ₂ O, Li ₂ O and K ₂ O, and the mole percentage of each component in the glass substrate for chemical strengthening which is easy to thermoform at the low softening point As a content, Na ₂ O accounts for 2.5% to 21%, Li ₂ O accounts for 5% to 18%, and K ₂ O accounts for 0.1% to 5%.

The alkaline earth metal oxide is MgO or CaO, and the molar percentage of the MgO or CaO in the glass substrate for chemical strengthening which is easy to be thermoformed at the low softening point is 0.1% to 8.5%.

The alkaline earth metal oxides are CaO and MgO, and CaO accounts for 0% to 5%, MgO, based on the mole percentage of each component at the low softening point and the glass substrate for chemical strengthening which is easy to thermoform. It accounts for 0.1% to 7%.

In addition to the above components, the glass substrate for chemical strengthening of the present invention having a low softening point and easy thermoforming may further include other components such as B ₂ O ₃ , Sb ₂ O ₃ , ZrO ₂ , TiO ₂ , SnO ₂ .

ZrO ₂ and TiO ₂ can improve the ion exchange rate, improve the chemical stability of the glass, increase the viscosity, hardness, and lower the coefficient of thermal expansion, and are sometimes preferably contained.

Sb ₂ O ₃ and SnO ₂ may be used singly or as a clarifying agent alone or in combination.

Preferably, the low softening point, thermoforming susceptible to chemical strengthening mole percent of 0% to 5% of the glass substrate B with the other oxides include ₂ O _3.

Preferably, the other oxide in the glass substrate for chemical strengthening which is low in softening point and which is easy to thermoform comprises Sb ₂ O _{3 in a} molar percentage of 0% to 5%.

Examples of five sets of low softening points of different ratios and easy to thermoform a glass substrate for chemical strengthening are given below:

Examples 1 and 2: According to the ratios in the table, the chemically strengthened glass substrates of Examples 1 and 2 have a softening point of less than 880 ° C, which is relatively easy to thermoform, and an ultra-high-strength ultra-thin glass material can be produced after ion exchange or The glass substrate can be used for thermoforming of non-planar glass (shaped glass), and is suitable for the preparation of curved electronic devices, such as mobile communication or the surface structure of a housing or screen of an information device.

Example 3: The chemically strengthened glass substrate of Example 3 had a softening point of less than 840 ° C according to the ratio in the table, and was more easily thermoformed than Examples 1 and 2.

Example 4: The chemically strengthened glass substrate of Example 4 had a softening point of less than 860 ° C according to the ratio in the table, and was more easily thermoformed than Examples 1 and 2.

Example 5: The chemically strengthened glass substrate of Example 5 had a softening point of less than 800 ° C according to the ratio in the table, and was more easily thermoformed than Examples 1 to 4.

For each of the glass substrates for chemical strengthening obtained in the above five examples, each of the glass substrates having a thickness of 1 mm was tested, and the light transmittance at a wavelength of 550 nm was 89.8 to 92. 2%. Compared with the prior art, the present invention has the following advantages:

First, the glass substrate for chemical strengthening of the low-softening point and the easy thermoforming of the present invention is composed of four components of SiO ₂ , Al ₂ O ₃ , Bi ₂ O ₃ and P ₂ O ₅ in accordance with a specific ratio to form a stable network structure. Larger backbone structure, and does not contain As ₂ O ₃ material; this main backbone structure makes the glass material have strong ion exchange property during chemical strengthening. That is, the ion exchange rate is more than double that of the ordinary aluminosilicate glass which does not contain the backbone structure in the same ion exchange salt bath at the same ion exchange temperature and time level, and does not contain the backbone structure. More than twice the amount of ordinary soda lime silicate glass.

Secondly, due to the composition of its components and components, it has a low softening point and is easy to be thermoformed. Its softening point can be as low as 880 ° C according to the combination of different contents of Bi ₂ O ₃ and P ₂ O ₅ . 860 ° C, 840 ° C, 800 ° C, such a chemical strengthening glass substrate, through the subsequent chemical strengthening process can produce ultra-high strength ultra-thin glass substrate, which has a low softening point, easy to thermoform Features, very suitable for thermoforming of non-planar glass (ie, shaped glass), for the preparation of curved electronic devices, such as mobile communication or the curved structure of the housing or screen of information equipment.

The above is only the preferred embodiment of the present invention, and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection of the present invention. Within the scope.

Claims (10)

A glass substrate for chemical strengthening having a low softening point and being easily thermoformed, wherein the glass substrate for chemical strengthening having a low softening point and being easily thermoformed has a softening point of less than 900 ° C, and is characterized by comprising a backbone component and an auxiliary group The backbone component comprises SiO ₂ , Al ₂ O ₃ , Bi ₂ O ₃ , P ₂ O ₅ , and the auxiliary component comprises an alkali metal oxide, and the components are at the low softening point, and are easy to heat. SiO ₂ accounts for 50% to 70%, Al ₂ O ₃ accounts for 5% to 17%, and Bi ₂ O ₃ accounts for 0.1% to 15%, P ₂ O, based on the mole percent of the glass for chemical strengthening. ₅ accounts for 0.1% to 10%, the molar percentage of the total of Bi ₂ O ₃ and P ₂ O ₅ is 2.5% to 22%, the alkali metal oxide accounts for 5% to 25%, and the low softening The glass for chemical strengthening which is easy to be thermoformed is a non-As material. The glass substrate for chemical strengthening according to claim 1, wherein the softening point and the glass substrate for chemical strengthening which are easy to be thermoformed have a softening point of less than 880 ° C. The molar content of Bi ₂ O ₃ in the backbone component is 0.1% to 5%, the molar percentage of P ₂ O ₅ is 0.1% to 3.5%, and the molar ratio of Bi ₂ O ₃ to P ₂ O ₅ is 100. The content of the fraction is 2.5% to 8.5%. The glass substrate for chemical strengthening according to claim 1, wherein the softening point and the glass substrate for chemical strengthening which are easy to be thermoformed have a softening point of less than 860 ° C. The molar content of Bi ₂ O ₃ in the backbone component is 0.1% to 5%, the molar percentage of P ₂ O ₅ is more than 3.5% and less than or equal to 5%, and the sum of Bi ₂ O ₃ and P ₂ O ₅ The molar percentage is 3.6% to 10%. The glass substrate for chemical strengthening according to claim 1, wherein the glass substrate for chemical strengthening having a low softening point and being easily thermoformed has a softening point of less than 840 ° C. The molar content of Bi ₂ O ₃ in the backbone component is 0.1% to 5%, the molar percentage of P ₂ O ₅ is more than 5% and less than or equal to 10%, and the sum of Bi ₂ O ₃ and P ₂ O ₅ The molar percentage is from 5.1% to 15%. The glass substrate for chemical strengthening according to claim 1, wherein the glass substrate for chemical strengthening having a low softening point and being easily thermoformed has a softening point of less than 800 ° C. The molar percentage of Bi ₂ O ₃ in the backbone component is greater than 7% and less than 15%, the molar percentage of P ₂ O ₅ is 0.1% to 10%, and the molar ratio of Bi ₂ O ₃ to P ₂ O ₅ The percentage is from 7.1% to 22%. The glass substrate for chemical strengthening according to claim 1, wherein the alkali metal oxide is at least one of K ₂ O, Na ₂ O, and Li ₂ O; The molar percentage of K ₂ O is not more than 5%, the molar percentage of Na ₂ O or Li ₂ O is not more than 23.5%; when both Na ₂ O and Li ₂ O are contained, Na ₂ O is 2.5% to 21 % and Li ₂ O account for 5% to 18%. The low-softening point, easy thermoformable glass substrate for chemical strengthening according to claim 1, wherein the alkali metal oxide comprises Na ₂ O and Li ₂ O at a low softening point of each component , susceptible to chemical strengthening by thermoforming mole percent content of the glass substrate occupied, Na ₂ O accounted for _{2.5% ~ 21%, Li 2} O , 5% to 18%. A glass substrate for chemical strengthening which is low in softening point and which is easy to thermoform according to claim 1, wherein the alkali metal oxide comprises Na ₂ O, Li ₂ O and K ₂ O, with each component being Na ₂ O accounts for 2.5% to 21%, Li ₂ O accounts for 5% to 18%, and K ₂ O accounts for 0.1% of the mole percentage of the glass substrate for chemical strengthening which is low in softening point and easy to thermoform. ~5%. The low-softening point, easy thermoformable glass substrate for chemical strengthening according to claim 1, wherein the auxiliary component further comprises an alkaline earth metal oxide, the alkaline earth metal oxide being at least at least CaO and MgO One type, in terms of the mole percentage of each component in the glass for chemical strengthening, CaO does not exceed 5%, and MgO does not exceed 7%. A method for preparing a glass substrate for chemical strengthening which has a low softening point and is easy to be thermoformed, and comprises the following steps: The raw material corresponding to the composition of the glass substrate for chemical strengthening of the low-softening point and the thermoforming which is easy to be thermoformed according to any one of claims 1 to 9, and the glass for chemical strengthening which is easy to be thermoformed according to the finally obtained low softening point Mixing the above raw materials in proportion to the molar percentage of each component in the substrate, placing the mixture in a crucible or a furnace, and stirring uniformly; Heating at 1400-1630 ° C to melt the mixture and clarify to obtain a molten glass liquid; The molten glass liquid is subjected to a forming treatment, and is slowly cooled and then annealed to obtain the glass substrate for chemical strengthening which is low in softening point and which is easily thermoformed.