CN115286241A - Ultrathin flexible glass with high fracture toughness and preparation method thereof - Google Patents

Abstract

The invention relates to ultrathin flexible glass with high fracture toughness and a preparation method thereof, which are characterized in that: siO 2 ₂ 55～65％、Al ₂ O ₃ 8～14％、B ₂ O ₃ 6～12％、P ₂ O ₅ 2～10％、Na ₂ O 5～16％、MgO 3～8％、Li ₂ O 0.5～5％、K ₂ 0.1 to 2 percent of O, and SnO accounting for 0.2 weight percent of the total weight of the raw materials is additionally added; (1) weighing the raw materials according to the proportion, putting the raw materials into a mortar, and uniformly mixing; (2) Pouring the mixed batch into a platinum crucible, putting the platinum crucible into a resistance type high-temperature box, and melting for 3-5h at 1560-1680 ℃; (3) Pouring the molten and clarified mixture onto a stainless steel plate for forming, transferring the formed product into an annealing furnace at the temperature of 580-620 ℃ for annealing for 25 DEG C-35min; (4) And after the annealing is finished, cooling to room temperature along with the furnace, and performing conventional thinning, strengthening and processing treatment. The invention has the advantages that: the hardness is ensured to be more than 570kgf.mm ^‑2 On the premise of improving the fracture toughness of the glass to 0.875-0.896 Mpa ^1/2 Thereby improving the bending property of the glass and preparing the ultrathin flexible glass with good bending radius.

Description

A kind of ultra-thin flexible glass with high fracture toughness and preparation method thereof

technical field

The invention belongs to the technical field of glass manufacturing, and relates to an ultra-thin flexible glass and a preparation method thereof.

Background technique

With the development of emerging fields such as non-flat panel displays and flexible displays, the market is increasingly interested in foldable electronic devices and flexible displays. At the same time, the application of flexible glass makes information display devices thinner and lighter, especially in the field of foldable screens. In order to meet the development of new fields, ultra-thin flexible glass is required to have the characteristics of high hardness, high transmittance, chemical corrosion resistance, etc., and also needs to meet the characteristics of bendability, light weight, and machinability. At present, it is difficult for ultra-thin flexible glass to achieve small curvature bending and repeated bending under the premise of maintaining high mechanical strength.

The bending mechanism of ultra-thin flexible glass is multifaceted, which can be analyzed from the aspects of glass composition and structure, processing technology and surface treatment. In the process of glass processing, a large number of micro-cracks will inevitably be generated on the surface of the glass. Due to the existence of these micro-cracks on the glass surface, the stress intensity factor at the tip of the crack gradually increases with the gradual increase of the external force. When the K value reaches a certain critical value, the crack will expand unstable and the glass will break brittlely. So how to improve the toughness of glass against crack instability expansion (fracture toughness of glass itself) is to improve the curvature of glass.

Patent Publication No. CN110128008A reduces and eliminates glass surface cracks and glass internal stress by optimizing the traditional process, and at the same time controls the glass surface compressive stress and ion exchange depth within a certain range to achieve high flexibility and high thermal shock resistance of the glass to achieve small curvature bending. Patent Publication No. CN107351462A improves the bending performance of flexible glass through processing technology. The polymerization degree of the glass structure is the main factor affecting the fracture toughness of the glass, and the reduction of the polymerization degree affects the strength, hardness and other properties of the glass. The influence of composition structure on fracture toughness is very complicated, and there is a contradiction between it and hardness. How to comprehensively consider from the perspective of components to find a balance point to coordinate the relationship between glass fracture toughness, strength and hardness is exactly what the present invention will solve.

Contents of the invention

The purpose of the present invention is to make up for the deficiencies of the prior art, and provide a kind of ultra-thin flexible glass and its preparation method; the present invention improves the fracture toughness of the glass under the premise of ensuring its hardness by adjusting the glass components, thereby improving The bending performance of glass, that is, improving the fracture toughness of glass from the perspective of glass composition and structure, thereby improving the bending performance of ultra-thin glass.

In order to achieve the above object, the technical scheme adopted in the present invention is as follows:

An ultra-thin flexible glass with high fracture toughness, characterized in that it is made of the following raw materials in weight percentage: SiO ₂ 55-65%, Al ₂ O ₃ 8-14%, B ₂ O ₃ 6-12%, P ₂ 2-10% of O ₅ , 5-16% of Na ₂ O, 3-8% of MgO, 0.5-5% of Li ₂ O, 0.1-2% of K ₂ O, and 0.2wt% SnO of the total weight of raw materials.

Further, the ultra-thin flexible glass with high fracture toughness is characterized in that it is made of the following raw materials in weight percentage: SiO ₂ 55-60%, Al ₂ O ₃ 10-14%, B ₂ O ₃ 6-10% %, P ₂ O ₅ 3-6%, Na ₂ O 5-12%, MgO 3-5%, Li ₂ O 3-4%, K ₂ O 0.5-2%, plus 0.2wt% of the total weight of raw materials SnO .

Further, the ultra-thin flexible glass with high fracture toughness is characterized in that it is made of the following raw materials in weight percentage: SiO ₂ 55-60%, Al ₂ O ₃ 10-14%, B ₂ O ₃ 6-8 %, P ₂ O ₅ 3~5%, Na ₂ O 10~12%, MgO 3~4%, Li ₂ O 3~3.5%, K ₂ O 0.6~1%, plus 0.2wt% of the total weight of raw materials SnO.

The content of _SiO2 in the glass of the present invention is between 55% and 65%. As the skeleton formed by the glass, _SiO2 can increase the strain point and reduce the coefficient of thermal expansion; but when the content is high, the high-temperature viscosity of the glass increases and the crystallization tendency increases; When too low, chemical corrosion resistance will fall.

The content of Al ₂ O ₃ in the glass of the present invention is 8-14wt%, and the Al ₂ O ₃ can increase Young's modulus, inhibit phase separation of glass, reduce thermal expansion coefficient, and increase strain point. In addition, for flexible glass, the increase of Al ₂ O ₃ content will improve the flexibility of the glass, but the relationship between content and flexibility is not a linear proportional relationship. According to the experiment, when Al ₂ O ₃ replaces SiO ₂ , aluminum will preferentially capture free Oxygen forms aluminum-oxygen tetrahedrons, corresponding boron-oxygen tetrahedrons decrease and boron-oxygen trihedrons increase, and silicon-oxygen tetrahedrons also decrease. Since the volume of the aluminum-oxygen tetrahedron is larger than that of the silicon-oxygen tetrahedron, the compactness of the network will decrease. The glass structure is loose, the hardness is also reduced, and the tensile strength is also reduced. When the content exceeds 14wt%, the glass flexibility index basically increases little; and too high Al ₂ O ₃ also reduces the fracture toughness of the glass. Therefore, in order to ensure the proper strength and hardness of the glass and enhance the glass flexibility, Al ₂ O ₃ The content should not exceed 14wt%.

The content of B ₂ O ₃ in the glass of the present invention is 6-12wt%, and B ₂ O ₃ can effectively reduce the expansion coefficient of the glass, thereby improving the thermal shock resistance of the glass, so that the tempering of the ultra-thin flexible glass can be improved in the later chemical tempering process High yield rate and low CS, DoL.

The content of P ₂ O ₅ in the glass of the present invention is 3-6%. P ₂ O ₅ can modify the network performance and reduce the melting temperature and working temperature, and make the glass structure open, so that Na ⁺ in the glass can more easily diffuse to the glass surface, Exchange with K ⁺ in lava. However, when the content is too high, the glass will be devitrified and the chemical stability will be affected.

The content of MgO in the glass of the present invention is 6-8wt%, and MgO is a component that reduces high-temperature viscosity and glass density and improves meltability, and changes the refractive index of the glass.

In the glass of the present invention, Na ₂ O, Li ₂ O, K ₂ O, and alkali metals can provide redundant oxygen ions in the glass, and are the main network structure silicon disconnecting the network to form non-bridging oxygen. Reduce the elastic modulus of the glass and increase the bending curvature of the glass. Sodium ions and lithium ions are also essential for the chemical toughening of ultrathin flexible glasses. In addition, for ultra-thin flexible glass, the overall content of alkali metal should not be too high, generally not more than 25%, because too high content will increase the expansion coefficient and destroy the glass network.

A method for preparing ultra-thin flexible glass with high fracture toughness, characterized in that it comprises the following steps:

(1) Weigh the raw materials according to the above weight percentage, and then put all the raw materials into the mortar and mix them evenly to prepare the glass batch;

(2) Pour the evenly mixed glass batch into a platinum crucible, then put it into a resistance high temperature box, and melt it at 1560-1680°C for 3-5h;

(3) After the ingredients are melted and clarified, pour them into a stainless steel plate for forming, and then transfer to an annealing furnace at a temperature of 580-620°C for annealing for 25-35 minutes to eliminate the residual stress in the glass structure;

(4) After the annealing is completed, cool down to room temperature with the furnace, and then perform conventional thinning, strengthening, processing and other processes after cooling down to room temperature to obtain an ultra-thin flexible glass.

Further, the melting temperature in the step (2) is 1580-1640°C.

Further, the melting temperature in the step (2) is 1640°C.

Further, the annealing temperature in the step (3) is 580-600°C.

Due to the extremely thin thickness of flexible glass, the bending performance of the glass will be poor when pulled during the preparation process, cracks and fractures will appear during the cutting and bending process, and the flexibility index is low. The use of chemical thinning and strengthening processes can reduce defects caused by cutting, and the bending performance of flexible glass will be further enhanced through chemical strengthening.

The advantages of the present invention: under the premise of ensuring its hardness (>570kgf.mm ^-2 ), the fracture toughness (0.875-0.896 Mpa.m ^1/2 ) of the glass is improved, and the bending performance of the glass is further improved. Ultra-thin flexible glass with good bend radius.

Detailed ways

A preparation method of ultra-thin flexible glass, the specific implementation steps are as follows:

Example 1

(1) Weigh raw materials according to the following mass percentages: SiO ₂ 58%, Al ₂ O ₃ 14%, B ₂ O ₃ 6%, P ₂ O ₅ 5%, Na ₂ O 10%, MgO 3%, Li ₂ O 3 %, K ₂ O 1%, plus 0.2wt% SnO of the total weight of raw materials;

(2) Then put all the raw materials into the mortar and mix them evenly to make the glass batch;

(3) Pour the uniformly mixed glass batch into a platinum crucible, then put it into a resistance high temperature box, and melt it at 1680°C for 3.5h;

(4) After the ingredients are melted and clarified, pour it into the mold, and after forming, transfer it to an annealing furnace at a temperature of 600°C for 30 minutes to eliminate the residual stress in the glass structure;

(5) After the annealing is completed, cool down to room temperature with the furnace, and then perform conventional thinning, strengthening, processing and other processes after cooling down to room temperature to obtain an ultra-thin flexible glass.

Example 2

(1) Weigh raw materials according to the following mass percentages: SiO ₂ 60%, Al ₂ O ₃ 10%, B ₂ O ₃ 8%, P ₂ O ₅ 3%, Na ₂ O 12%, MgO 3%, Li ₂ O 3 %, K ₂ O 1%, plus 0.2wt% SnO of the total weight of raw materials;

(2) Then put all the raw materials into the mortar and mix them evenly to make the glass batch;

(3) Pour the uniformly mixed glass batch into a platinum crucible, then put it into a resistance high temperature box, and melt it at 1680°C for 3.5h;

(4) After the ingredients are melted and clarified, pour it into the mold, and after forming, transfer it to an annealing furnace at a temperature of 580 ° C for 30 minutes to eliminate the residual stress in the glass structure;

(5) After the annealing is completed, cool down to room temperature with the furnace, and then perform conventional thinning, strengthening, processing and other processes after cooling down to room temperature to obtain an ultra-thin flexible glass.

Example 3

(1) Weigh raw materials according to the following mass percentages: SiO ₂ 55%, Al ₂ O ₃ 12%, B ₂ O ₃ 8%, P ₂ O ₅ 4%, Na ₂ O 3%, MgO 3%, Li ₂ O 3.5 %, K ₂ O 1.5%, plus 0.2wt% SnO of the total weight of raw materials;

(2) Then put all the raw materials into the mortar and mix them evenly to make the glass batch;

(3) Pour the uniformly mixed glass batch into a platinum crucible, then put it into a resistance high temperature box, and melt it at 1680°C for 3.5h;

(4) After the ingredients are melted and clarified, pour them into the mold, and after forming, transfer them to an annealing furnace at a temperature of 605°C for 30 minutes to eliminate the residual stress in the glass structure;

(5) After the annealing is completed, cool down to room temperature with the furnace, and then perform conventional thinning, strengthening, processing and other processes after cooling down to room temperature to obtain an ultra-thin flexible glass.

Table 1

Oxide Composition (wt%) Example 1 Example 2 Example 3 SiO₂ 58 60 55 Al₂O₃ 14 10 12 B₂O₃ 6 8 8 P₂O₅ 5 3 4 Na₂O 10.5 12 12 MgO 3 3 3 Li₂O 2.5 3 3.5 K₂O 1 1 1.5 SnO 0.2 0.2 0.2

The following table 2 is the flexible glass on the market as the control group

Table 2

Oxide Composition (wt%) Comparative example 1 Comparative example 2 SiO₂ 62 70 Al₂O₃ 18 2 B₂O₃ 3.5 - K₂O 2.5 1 Na₂O 9.5 13 MgO 7 4 CaO 3 10

The following table 3 is the comparison table of the various performance results of the embodiment and the contrast group

table 3

Example Example 1 Example 2 Example 3 Comparative example 1 Comparative example 2 Elastic modulus/GPa 2.503 2.497 2.491 2.511 2.501 Vickers hardness/(kgf.mm^-2) 578.5 585.8 589.8 605.2 599.6 Tensile strength/MPa 76.976 73.795 73.751 68.175 66.575 Fracture toughness/Mpa.m^1/2 0.896 0.875 0.877 0.675 0.661

The above description is only a preferred embodiment of the present invention, and is not intended to limit the present invention in any form. It should be pointed out that for those of ordinary skill in the art, they can also make Several improvements and transformations all belong to the protection scope of the present invention.

Claims (7)

1. The ultrathin flexible glass with high fracture toughness is characterized by being prepared from the following raw materials in percentage by weight: siO 2 ₂ 55～65％、Al ₂ O ₃ 8～14％、B ₂ O ₃ 6～12％、P ₂ O ₅ 2～10％、Na ₂ O 5～16％、MgO 3～8％、Li ₂ O 0.5～5％、K ₂ 0.1 to 2 percent of O and SnO accounting for 0.2 weight percent of the total weight of the raw materials are added.

2. The ultra-thin flexible glass with high fracture toughness of claim 1 is characterized by being prepared from the following raw materials in percentage by weight: siO 2 ₂ 55～60％、Al ₂ O ₃ 10～14％、B ₂ O ₃ 6～10％、P ₂ O ₅ 3～6％、Na ₂ O 5～12％、MgO 3～5％、Li ₂ O 3～4％、K ₂ 0.5 to 2 percent of O and SnO accounting for 0.2 weight percent of the total weight of the raw materials are added.

3. The ultra-thin flexible glass with high fracture toughness of claim 1 is characterized by being prepared from the following raw materials in percentage by weight: siO 2 ₂ 55～60％、Al ₂ O ₃ 10～14％、B ₂ O ₃ 6～8％、P ₂ O ₅ 3～5％、Na ₂ O 10～12％、MgO 3～4％、Li ₂ O 3～3.5％、K ₂ 0.6 to 1 percent of O and SnO accounting for 0.2 weight percent of the total weight of the raw materials are added.

4. The method for preparing the ultrathin flexible glass with high fracture toughness according to claim 1 is characterized by comprising the following steps:

(1) Weighing the raw materials according to the weight percentage, and then putting all the raw materials into a mortar for uniformly mixing to prepare a glass batch;

(2) Pouring the uniformly mixed glass batch into a platinum crucible, then putting the platinum crucible into a resistance type high-temperature box, and melting for 3-5h at 1560-1680 ℃;

(3) After the ingredients are melted and clarified, pouring the ingredients onto a stainless steel plate for forming, and then transferring the formed mixture into an annealing furnace with the temperature of 580-620 ℃ for annealing for 25-35min to eliminate residual stress in a glass structure;

(4) And after the annealing is finished, cooling to room temperature along with the furnace, and performing conventional thinning, strengthening and processing treatment after the temperature is reduced to the room temperature to obtain the ultrathin flexible glass.

5. The method for preparing the ultrathin flexible glass with high fracture toughness of claim 5, wherein the method comprises the following steps: the melting temperature in the step (2) is 1580-1640 ℃.

6. The method for preparing ultra-thin flexible glass with high fracture toughness according to claim 5, characterized in that the melting temperature in the step (2) is 1640 ℃.

7. The method for preparing ultra-thin flexible glass with high fracture toughness as claimed in claim 5, characterized in that the annealing temperature in step (3) is 580-600 ℃.