CN114873927B - A UTG chemical strengthening process - Google Patents

Abstract

The invention provides a UTG chemical strengthening process, which comprises the following steps: a) Immersing UTG material to be chemically strengthened into HF solution for double-sided etching; the concentration of the HF solution is 1-4 mol/L; the double-sided etching time is 10-20 min; b) Cleaning to remove residual acid on the surface of UTG, and preheating to 360-390 ℃; c) Immersing the preheated UTG into strengthening liquid for chemical strengthening; d) The chemically strengthened UTG was annealed and soaked in water to give a strengthened UTG. According to the invention, through the process combination of etching before tempering and etching after tempering, the apparent reject ratio of the UTG product is reduced from 90% to below 10%, meanwhile, the reject ratio is greatly reduced, the trial production requirement is primarily met, and meanwhile, the process in the invention improves the processing limit capability of the chemical strengthening process in the aspect of product thickness, and the thickness of the processable product can be as low as 0.03mm.

Description

A UTG chemical strengthening process

Technical field

The invention belongs to the technical field of ultra-thin flexible glass production, and particularly relates to a UTG chemical strengthening process.

Background technique

At present, mainstream mobile phone manufacturers will focus on folding screens as a means of mobile phone innovation and entering the high-end market.

Currently, the mass-produced and marketed flexible folding cover materials are mainly divided into two types: CPI (transparent polyimide film) and UTG (ultra-thin flexible glass). CPI is an engineering plastic; UTG is a glass that is flexible when the thickness is less than 100 μm, so it can be thin and bendable while maintaining the advantages of the glass itself. Compared with CPI, the advantages of UTG are: 1) High transmittance: UTG is based on the characteristics of glass, with a transmittance of more than 90%; 2) Strong durability: UTG material has strong durability and is not easily damaged or scratched after bending. Better touch; 3) Good high temperature resistance: UTG has better high temperature resistance.

In order to enhance the flexibility and durability of UTG, UTG usually needs to be strengthened. The conventional strengthening process is generally only used for glass products with a thickness of 0.15mm or above. For ultra-thin glass (UTG) with a thickness of <0.15mm, the fragmentation rate is directly applied. More than 90%, and the product has obvious warping deformation and poor regional dents, which cannot meet the needs of use.

Contents of the invention

The purpose of the present invention is to provide a UTG chemical strengthening process. The UTG chemical strengthening process in the present invention can effectively reduce the proportion of UTG glass warpage defects and improve the production yield.

The invention provides a UTG chemical strengthening process, which includes the following steps:

A) Immerse the UTG material to be chemically strengthened into the HF solution and perform double-sided etching;

The concentration of the HF solution is 1 to 4 mol/L; the double-sided etching time is 10 to 20 minutes;

B) Clean and remove the residual acid on the UTG surface, and then raise the temperature for preheating;

C) Immerse the preheated UTG into the strengthening solution for chemical strengthening;

D) Anneal the chemically strengthened UTG and soak it in water to obtain the strengthened UTG.

Preferably, after soaking in water, the soaked UTG is immersed in an HF solution, and a second double-sided etching is performed to obtain the strengthened UTG.

Preferably, the concentration of the HF solution used in the second double-sided etching is 0.5-2 mol/L.

Preferably, the second double-sided etching time is 5 to 10 minutes.

Preferably, the preheating temperature is 360-390°C.

Preferably, the strengthening liquid is molten potassium nitrate.

Preferably, the chemical strengthening time is 10 to 30 minutes; the chemical strengthening temperature is 380 to 400°C.

Preferably, the annealing temperature is 60-90°C; the annealing time is 3-6 hours.

Preferably, the temperature of the soaking water is 40-60°C.

Preferably, the thickness of the UTG is <0.15mm.

The invention provides a UTG chemical strengthening process, which includes the following steps: A) immersing the UTG material to be chemically strengthened in an HF solution and performing double-sided etching; the concentration of the HF solution is 1 to 4 mol/L; The surface etching time is 10 to 20 minutes; B) Clean and remove the residual acid on the UTG surface, and then preheat to 360 to 390°C; C) Dip the preheated UTG into the strengthening solution for chemical strengthening; D) Add the chemical The strengthened UTG is annealed and soaked in water to obtain the strengthened UTG. The present invention uses HF acid to etch both sides of the glass before chemical strengthening, so that the surface conditions of both sides of the glass before tempering are consistent, and the stress layer is evenly distributed after tempering, thereby reducing the occurrence of warpage. Furthermore, after chemical strengthening, it is etched with HF acid to release part of the stress layer on the surface and restore the warped state that has occurred to normal. Through the process combination of etching before tempering and etching after tempering, the present invention reduces the apparent defective rate of UTG products from 90% to less than 10%. At the same time, the degree of defectiveness is greatly reduced, which initially meets the needs of trial production. At the same time, the process in the present invention is improved. The chemical strengthening process has the ultimate processing capability in terms of product thickness. The thinnest product thickness that can be processed can be as low as 0.03mm.

Detailed ways

The invention provides a UTG chemical strengthening process, which includes the following steps:

A) Immerse the UTG material to be chemically strengthened into the HF solution and perform double-sided etching;

The concentration of the HF solution is 1 to 4 mol/L; the double-sided etching time is 10 to 20 minutes;

B) Clean and remove the residual acid on the UTG surface, and then preheat to 360~390℃;

C) Immerse the preheated UTG into the strengthening solution for chemical strengthening;

D) Anneal the chemically strengthened UTG and soak it in water to obtain the strengthened UTG.

In the present invention, the thickness of the UTG material is preferably less than 0.15mm, and UTG materials as thin as 0.03mm are also suitable for the chemical strengthening process in the present invention.

In the present invention, the UTG material to be chemically strengthened is first immersed in an HF solution, and double-sided etching is performed to obtain the UTG material after the first etching.

In the present invention, the mass concentration of the HF solution is preferably 1 to 4 mol/L, more preferably 2 to 3 mol/L, such as 1 mol/L, 1.5 mol/L, 2 mol/L, 2.5 mol/L, 3 mol/L. L, 3.5mol/L, 4mol/L, preferably a range value with any of the above values as the upper limit or lower limit; the double-sided etching time is preferably 10 to 20min, such as 10min, 11min, 12min, 13min, 14min, 15min , 16min, 17min, 18min, 19min, 20min, preferably a range value with any of the above values as the upper limit or lower limit; the temperature of the double-sided etching is preferably 17~36°C, more preferably 20~30°C, such as 17°C , 18℃, 19℃, 20℃, 21℃, 22℃, 23℃, 24℃, 25℃, 26℃, 27℃, 28℃, 29℃, 30℃, 31℃, 32℃, 33℃, 34 °C, 35°C, and 36°C, preferably a range value with any of the above numerical values as the upper limit or lower limit.

After the first double-sided etching is completed, the present invention cleans the etched UTG material to remove HF acid residue and other surface dirt to ensure that the product surface is clean.

The cleaning specifically includes first using a sodium hydroxide solution with a mass concentration of 8 to 20%, and then using pure water to clean 4 to 5 times. The cleaning temperature is preferably 50 to 80°C, and more preferably 60 to 60°C. 70℃.

After completing the cleaning, the present invention raises the temperature of the cleaned UTG material from normal temperature to preheat.

In the present invention, the heating rate is preferably 2-3°C/min; the preheating temperature is 360-390°C, more preferably 370-380°C.

Then the preheated UTG material is immersed in the strengthening liquid for chemical strengthening.

In the present invention, the strengthening liquid is preferably molten potassium nitrate; the temperature of the chemical strengthening is preferably 380-400°C, such as 380°C, 385°C, 390°C, 395°C, 400°C, preferably the above Any numerical value is the upper or lower limit of the range; the chemical strengthening time is preferably 10 to 30 min, more preferably 15 to 25 min, such as 10 min, 15 min, 20 min, 25 min, 30 min, preferably any of the above numerical values is the upper or lower limit range value.

After the strengthening step, in the present invention, the strengthened UTG material is taken out from the strengthening liquid, annealed, and cooled from the chemical strengthening temperature to 60-90°C.

In the present invention, the cooling rate of the annealing is preferably 1-2°C/min; the annealing temperature is preferably 70-80°C.

Then, the present invention soaks the annealed UTG material in pure water at 50-55°C to dissolve and remove the salt residue on the surface.

In the present invention, it is preferred to perform a second etching after chemical strengthening, and soak the UTG material soaked in water in an HF solution to perform a second double-sided etching.

In the present invention, the mass concentration of the HF solution is preferably 0.5~2mol/L, more preferably 1~1.5mol/L, such as 0.5mol/L, 1mol/L, 1.5mol/L, 2mol/L, preferably It is a range value with any of the above numerical values as the upper or lower limit; the double-sided etching time is preferably 5 to 10 min, such as 5 min, 6 min, 7 min, 8 min, 9 min, 10 min, preferably with any of the above numerical values as the upper or lower limit. Range value; the temperature of the double-sided etching is preferably 17~36°C, more preferably 20~25°C, such as 17°C, 18°C, 19°C, 20°C, 21°C, 22°C, 23°C, 24°C, 25°C, 26°C, 27°C, 28°C, 29°C, 30°C, 31°C, 32°C, 33°C, 34°C, 35°C, 36°C, preferably a range value with any of the above values as the upper limit or lower limit.

The invention provides a UTG chemical strengthening process, which includes the following steps: A) immersing the UTG material to be chemically strengthened in an HF solution and performing double-sided etching; the mass concentration of the HF solution is 1 to 4 mol/L; The double-sided etching time is 10 to 20 minutes; B) Clean and remove the residual acid on the UTG surface, and then preheat to 360 to 390°C; C) Immerse the preheated UTG into the strengthening solution for chemical strengthening; D) The chemically strengthened UTG is annealed and soaked in water to obtain the strengthened UTG. The present invention uses HF acid to etch both sides of the glass before chemical strengthening, so that the surface conditions of both sides of the glass before tempering are consistent, and the stress layer is evenly distributed after tempering, thereby reducing the occurrence of warpage. Furthermore, after chemical strengthening, it is etched with HF acid to release part of the stress layer on the surface and restore the warped state that has occurred to normal. Through the process combination of etching before tempering and etching after tempering, the present invention reduces the apparent defective rate of UTG products from 90% to less than 10%. At the same time, the degree of defectiveness is greatly reduced, which initially meets the needs of trial production. At the same time, the process in the present invention is improved. The chemical strengthening process has the ultimate processing capability in terms of product thickness. The thinnest product thickness that can be processed can be as low as 0.03mm.

In order to further illustrate the present invention, a UTG chemical strengthening process provided by the present invention is described in detail below in conjunction with the examples, but this should not be understood as limiting the protection scope of the present invention.

Examples 1 to 8

①HF acid etching. Soak the product to be processed exposed in a 2.5 mol/L HF acid solution for double-sided etching. See Table 1 for etching time.

②Cleaning. Clean to remove HF acid residue and other surface dirt to ensure product surface is clean.

③Preheat. Raise the product from room temperature to 390°C.

④ Strengthen. Soak the product in strengthening liquid (molten potassium nitrate) for a period of time. The soaking time is 15 minutes and the strengthening temperature is 390°C.

⑤Annealing. After the product is taken out of the strengthening liquid, it is cooled from the strengthening temperature to 50°C.

⑥Soak in water. Soak the product in 50°C pure water to dissolve and remove the salt residue on the surface.

⑦HF acid etching. The product to be treated is immersed in a 1 mol/L HF acid solution, and double-sided etching is performed to repair the apparent warpage. See Table 1 for etching time.

Comparative example 1

The UTG is chemically strengthened according to the steps in Embodiment 1, except that the UTG material is not chemically strengthened or etched after chemical strengthening.

Table 1 Process and strengthening results of Examples 1 to 8

As can be seen from Table 1, only increasing etching before tempering can effectively reduce the proportion of warpage defects (from 95% to 50%). On the basis of etching before tempering, combined with etching after tempering, the proportion of warpage defects can be reduced at the same time (from 95% to 50%). 95% to 15%), warpage (from 5.1mm to 1.1mm).

The above are only the preferred embodiments of the present invention. It should be pointed out that those of ordinary skill in the art can also make several improvements and modifications without departing from the principles of the present invention. These improvements and modifications can also be made. should be regarded as the protection scope of the present invention.

Claims (7)

1. A UTG chemical strengthening process comprising the steps of:

a) Immersing UTG material to be chemically strengthened into HF solution for double-sided etching;

the concentration of the HF solution is 1-4 mol/L; the double-sided etching time is 10-20 min;

b) Cleaning to remove residual acid on the surface of UTG, and then heating to preheat;

c) Immersing the preheated UTG into strengthening liquid for chemical strengthening;

d) Annealing and soaking the UTG subjected to chemical reinforcement, immersing UTG subjected to soaking in an HF solution, and performing double-sided etching for the second time to obtain UTG subjected to reinforcement;

the concentration of the HF solution used in the second double-sided etching is 0.5-2 mol/L; the second double-sided etching time is 5-10 min.

2. The UTG chemical strengthening process of claim 1, wherein the preheating is at a temperature of 360 to 390 ℃.

3. The UTG chemical strengthening process of claim 1, wherein the strengthening liquid is molten potassium nitrate.

4. A UTG chemical strengthening process according to claim 3, wherein the chemical strengthening time is from 10 to 30 minutes; the temperature of the chemical strengthening is 380-400 ℃.

5. The UTG chemical strengthening process of claim 1, wherein the annealing temperature is from 60 ℃ to 90 ℃; the annealing time is 3-6 hours.

6. The chemical strengthening process of claim 1, wherein the soaking water has a temperature of 40-60 ℃.

7. The chemical strengthening process of claim 1, wherein the UTG has a thickness of <0.15 mm.