An unequal-thickness flexible foldable glass and its preparation process

Abstract

The present invention discloses a preparation process for flexible foldable glass with unequal thicknesses, comprising the following steps: S1, arranging an etching solution channel above the glass to be processed to guide the etching solution to flow through the area to be etched; S2, introducing the etching solution into the etching solution channel, and forming an arc-shaped groove in the area to be etched through etching; S3, separating the glass to be processed from the etching solution channel, performing acid-resistant protection on the glass surface where the arc-shaped groove is formed, and chemically thinning the other side of the glass to the target thickness, thus obtaining the flexible foldable glass with unequal thicknesses. The flexible foldable glass with unequal thicknesses prepared by the present invention can take into account foldability, hardness, and impact resistance.

Description

Technical Field

[0001] The present invention belongs to the technical field of flexible glass, and particularly relates to an unequal-thickness flexible foldable glass and a preparation process thereof. Background Art

[0002] As an important material for flexible display, flexible foldable glass has been rapidly developed in recent years. The so-called flexible foldable glass refers to ultra-thin glass with a thickness of ≤ 0.1 mm in the folding area. Flexibility means that the glass is very flexible, and under this flexibility, the glass can be bent without breaking. Compared with ordinary glass, flexible glass not only has the hardness, transparency, heat resistance of glass, as well as stable mechanical and chemical properties under oxidation and light conditions, but also has the characteristics of being bendable, lightweight, and processable. With the introduction of a series of new products such as flexible displays and flexible solar cells, flexible glass, as a new type of special glass, has become a research hotspot at home and abroad.

[0003] At present, the production methods of flexible foldable glass include the secondary chemical thinning process and the one-step direct forming. Among them, the chemical thinning method is aimed at the network structure of the glass, and different thinning solutions are used to etch the glass surface to reduce the glass thickness and achieve the purpose of flexibility.

[0004] However, currently, flexible glass is directly thinned in thickness or thinned to less than 0.1 mm by chemical thinning. At the same time, in order to further reduce the bending radius of the glass, the glass is thinned again to 0.03 mm. In this way, although the bending radius of the glass is reduced, the strength of the glass also drops significantly. At this time, as the protective cover plate of the display, the safety of the glass is reduced to a certain extent. Summary of the Invention

[0005] Based on the above technical problems, the present invention provides an unequal-thickness flexible foldable glass and a preparation process thereof. The folding area thickness of the unequal-thickness flexible foldable glass prepared by the present invention is as low as 0.03 mm, ensuring good bending performance, and the non-folding area thickness is greater than 0.03 mm, ensuring the glass strength.

[0006] The specific technical solution of the present invention is as follows

[0007] The present invention provides a preparation process for an unequal-thickness flexible foldable glass, including the following steps: S1. Set an etching solution channel above the glass to be processed to guide the etching solution to flow through the area to be etched; S2. Introduce the etching solution into the etching solution channel, and after etching, form an arc-shaped groove in the area to be etched; S3. Separate the glass to be processed from the etching solution channel, perform acid-resistant protection on the glass surface where the arc-shaped groove is formed, and chemically thin the other side of the glass to the target thickness, thereby obtaining the unequal-thickness flexible foldable glass.

[0008] The present invention utilizes the characteristics of fluids, i.e., the etching solution in the etching solution channel has a faster speed in the middle and slower speeds at both ends, as Figure 3 shown, resulting in the glass area to be etched being eroded to form an arc-shaped groove with thicker ends and thinner middle under the action of the etching solution with different flow rates. The arc-shaped groove ensures good bending and folding performance of the glass. The thicker thickness at both ends where bending is not required can ensure higher hardness and impact resistance of the glass. The obtained flexible foldable glass with unequal thickness can balance foldability and impact resistance.

[0009] Compared with the existing processes for forming grooves in the glass folding area, such as the CNC process or hot pressing process used in CN112679101A, the process of the present invention avoids defects such as scratches and cracks on the glass caused by mechanical processing when forming grooves. The groove obtained by the present invention is arc-shaped, and the glass thickness in the area to be etched gradually decreases in a curve form. Since there are no thickness mutation points and stress concentration points, the damage to the glass strength caused by the stress concentration effect is avoided.

[0010] "Guiding the etching solution to flow through the area to be etched" as described in the present invention means that the etching solution can flow from one end to the other end of the area to be etched and achieve etching of the entire area to be etched, without blind spots in etching. The area to be etched is set according to the glass folding area.

[0011] Preferably, S1 is specifically: placing two acid-resistant plates vertically and parallel above the glass to be processed, connecting the acid-resistant plates and the glass to be processed with pyrolytic acid-resistant glue, i.e., forming an etching solution channel between the two acid-resistant plates; the two ends of the acid-resistant plates span the glass to be processed, and the distance between the two acid-resistant plates is set according to the width of the area to be etched.

[0012] Preferably, in S1, the etching solution channel is placed between two glasses to be processed that are parallel up and down, and etching of the two glasses can be achieved simultaneously.

[0013] Preferably, in S2, the etching solution pressure is 0.02 - 0.1 kg / cm 2 , the etching solution temperature is 20 - 45 °C, and the etching time is 1 - 30 min.

[0014] Preferably, in S2, the etching solution pressure is 0.02 - 0.05 kg / cm 2 , the etching solution temperature is 25 - 35 °C, and the etching time is 8 - 20 min.

[0015] Preferably, in S3, the glass is separated from the etching solution channel by heating and decomposing the glue; preferably, the glass surface forming the arc-shaped groove is protected from acid by covering a pyrolytic acid-resistant film.

[0016] Preferably, in S3, the chemical thinning adopts the top spray process.

[0017] Preferably, it further includes S4, chemically strengthening the glass after chemical thinning.

[0018] The present invention also provides an unequal-thickness flexible foldable glass, which is prepared according to any one of the above processes.

[0019] Preferably, the thickness of the arc-shaped groove part of the unequal-thickness flexible foldable glass is less than the thickness of other parts; the distance from the bottom of the arc-shaped groove to the side away from the groove < 0.1 mm; more preferably, the distance from the bottom of the groove to the side away from the groove is 0.03 ± 0.005 mm.

[0020] Compared with the prior art, the beneficial effects are as follows:

[0021] The thinnest part of the unequal-thickness flexible foldable glass obtained by the present invention can be as low as 0.03 mm, and the foldable area has an arc-shaped groove structure, and the thickness gradually decreases in a curve form; the thickness of the non-foldable area is greater than 0.03 mm. The obtained unequal-thickness flexible foldable glass can balance foldability, hardness and impact resistance. After testing, the number of bending times is greater than 500,000 times, and the height of the pen drop is as high as 42 mm, which can be better applied in foldable mobile phones or foldable panels. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is the front view of the etching solution channel of the present invention;

[0023] Figure 2 It is the processing schematic diagram of the unequal-thickness flexible foldable glass of the present invention;

[0024] Figure 3 It is the schematic diagram of the etching solution speed in the etching solution channel of the present invention;

[0025] Figure 4 It is the schematic diagram of the unequal-thickness flexible foldable glass prepared in Example 1;

[0026] Figure 5 It is the schematic diagram of the unequal-thickness flexible foldable glass prepared in Comparative Example 1;

[0027] Figure 6 It is the schematic diagram of the unequal-thickness flexible foldable glass prepared in Comparative Example 2; DETAILED DESCRIPTION OF THE EMBODIMENTS

[0028] Next, the technical solutions of the present invention will be described in detail through specific examples, but it should be clearly stated that these examples are for illustrative purposes only and are not construed as limiting the scope of the present invention.

[0029] The glass used in the following examples is high-aluminum silicate glass with dimensions: length 158 mm, width 108 mm, and thickness 0.25 mm. The acid-resistant plate for building the etching solution channel is an acid-resistant plastic plate with a thickness of 2 mm, a length of 108 mm, and a width of 4.5 mm.

[0030] Example 1

[0031] An unequal-thickness flexible foldable glass, wherein the thickness of the arc-shaped groove part on the glass is less than that of other parts, the distance from the bottom of the arc-shaped groove to the side away from the groove is 0.03 mm, and the thickness of other parts is 0.1 mm; it is prepared by the following process:

[0032] S1. An etching solution channel for guiding the etching solution to flow through the area to be etched is arranged above the glass to be processed. The specific method is: place two acid-resistant plastic plates vertically and parallel above the glass to be processed, and bond the two acid-resistant plates to the upper and lower glasses to be processed through UV pyrolysis acid-resistant glue. An etching solution channel is formed between the two acid-resistant plastic plates;

[0033] The length of the etching solution channel is the length of the acid-resistant plastic plate, which is 108 mm and equal to the width of the glass to be processed, which can ensure that the acid-resistant plastic plate straddles the glass to be processed, thereby guiding the etching solution to flow through the area to be etched; the distance between the two acid-resistant plastic plates is set according to the width of the area to be etched; the width of the area to be etched is the width of the folding area;

[0034] S2. Introduce the etching solution into the etching solution channel, control the etching solution pressure to be 0.1 kg / cm 2 , the etching solution temperature is 35 °C, and the etching time is 2 min;

[0035] According to the characteristics of the fluid, since the flow rate of the etching solution in the etching solution pipeline shows a fast speed in the middle and a slow speed at both ends, the erosion effect on the glass shows a fast erosion in the middle and a slow erosion at both ends. Under this condition, an arc-shaped groove with an arc top height of 0.07 mm is formed in the area to be etched on the glass;

[0036] S3. After the etching is completed, wash, heat to remove the glue, separate the upper and lower glasses from the etching solution channel, and wash them clean; cover a layer of UV pyrolysis acid-resistant film on the glass surface where the arc-shaped groove is formed through a film laminator. After curing, place it in an acid-resistant fixture, and place the acid-resistant fixture containing the glass in a glass etching tank and use the top spray process for chemical thinning until the thickness of other parts except the arc-shaped groove is 0.1 mm, and the distance from the bottom of the arc-shaped groove to the side away from the arc-shaped groove is 0.03 mm.

[0037] S4. Cut the chemically thinned glass and perform chemical tempering to obtain the unequal-thickness flexible foldable glass.

[0038] Example 2

[0039] An unequal-thickness flexible foldable glass, wherein the thickness of the arc-shaped groove part on the glass is less than that of other parts, the distance from the bottom of the arc-shaped groove to the side far away from the groove is 0.03 mm, and the thickness of other parts is 0.09 mm; it is prepared according to the following process:

[0040] S1. The same as in Example 1;

[0041] S2. Introduce etching solution into the etching solution channel, control the etching solution pressure to be 0.05 kg / cm 2 , the etching solution temperature is 35 °C, and the etching time is 4 min;

[0042] According to the fluid characteristics, since the flow rate of the etching solution in the etching solution pipeline shows that the speed in the middle is fast and the speed at both ends is slow, the etching effect on the glass shows that the etching in the middle is fast and the etching at both ends is slow. Under this condition, an arc-shaped groove with an arc top height of 0.06 mm is formed in the area to be etched on the glass;

[0043] S3. After the etching is completed, wash, heat and remove the glue, separate the upper and lower glass sheets from the etching solution channel, and wash them clean; cover a layer of UV thermally decomposable acid-resistant film on the glass surface where the arc-shaped groove is formed through a laminating machine, cure it and put it into an acid-resistant fixture, and put the acid-resistant fixture containing the glass into a glass etching tank and use the top spray process for chemical thinning until the thickness of other parts except the arc-shaped groove is 0.09 mm, and the distance from the bottom of the arc-shaped groove to the side far away from the arc-shaped groove is 0.03 mm;

[0044] S4. Cut the chemically thinned glass and perform chemical tempering to obtain the unequal-thickness flexible foldable glass.

[0045] Example 3

[0046] An unequal-thickness flexible foldable glass, wherein the thickness of the arc-shaped groove part on the glass is less than that of other parts, the distance from the bottom of the arc-shaped groove to the side far away from the groove is 0.03 mm, and the thickness of other parts is 0.10 mm; it is prepared according to the following process:

[0047] S1. The same as in Example 1;

[0048] S2. Introduce etching solution into the etching solution channel, the etching solution pressure is 0.02 kg / cm 2 , the etching solution temperature is 30 °C, and the etching time is 2 min;

[0049] According to the fluid characteristics, since the flow rate of the etching solution in the etching solution pipeline shows that the speed in the middle is fast and the speed at both ends is slow, the etching effect on the glass shows that the etching in the middle is fast and the etching at both ends is slow. Under this condition, an arc-shaped groove with an arc top height of 0.05 mm is formed in the area to be etched on the glass;

[0050] S3. After the etching is completed, wash the glass, heat it to remove the glue, separate the upper and lower glass sheets from the etching solution channel, and clean them thoroughly. Cover a layer of UV thermally decomposable acid-resistant film on the glass surface with the arc-shaped groove through a laminating machine. After curing, place it in an acid-resistant jig. Put the acid-resistant jig with the glass into the glass etching tank and use the top spray process to chemically thin the glass until the thickness of the other parts except the arc-shaped groove is 0.08 mm, and the distance from the bottom of the arc-shaped groove to the side far from the arc-shaped groove is 0.03 mm.

[0051] S4. Cut the chemically thinned glass and then chemically strengthen it to obtain the unequal-thickness flexible foldable glass.

[0052] Comparative Example 1

[0053] An unequal-thickness flexible foldable glass, wherein the thickness of the groove part on the glass is less than that of the other parts, the distance from the bottom of the groove to the side far from the groove is 0.03 mm, and the thickness of the other parts is 0.1 mm. It is prepared according to the following process:

[0054] (1) Use the hot pressing process to form the groove: Heat a 0.20 mm, 108×158 mm high-aluminum silicate glass above the softening point, process the female mold and male mold according to the dimensions, and hot press to obtain the glass with the groove. The shape of the groove is as Figure 5 shown;

[0055] (2) Cover a layer of UV thermally decomposable acid-resistant film on the glass surface with the groove through a laminating machine. After curing, place it in an acid-resistant jig. Put the acid-resistant jig with the glass into the glass etching tank and use the top spray process to chemically thin the glass until the thickness of the other parts is 0.1 mm, and the distance from the bottom of the groove to the side far from the groove is 0.03 mm.

[0056] (3) Cut the chemically thinned glass and then chemically strengthen it to obtain the unequal-thickness flexible foldable glass.

[0057] Comparative Example 2

[0058] An unequal-thickness flexible foldable glass, wherein the thickness of the groove part on the glass is less than that of the other parts, the distance from the bottom of the groove to the side far from the groove is 0.03 mm, and the thickness of the other parts is 0.1 mm. It is prepared according to the following process:

[0059] (1) Use the CNC process to form the groove: Use CNC to process a 0.20 mm, 108×158 mm high-aluminum silicate glass to obtain the glass with a groove at the bottom. The shape of the groove is as Figure 6 shown;

[0060] (2)(3) The steps are the same as those in Comparative Example 1.

[0061] Comparative Example 3

[0062] A flexible foldable glass with uniform thickness, where the thickness of each part of the glass is 0.03 mm. It is obtained by chemically thinning a 0.25 mm thick, 108×158 mm high-aluminum silicate glass and then chemically tempering it.

[0063] Performance testing

[0064] The folding times and pen-drop performance of the flexible foldable glass obtained in the above examples and comparative examples were tested. The testing method is as follows:

[0065] (1) Folding times: Fix the non-folded part of the flexible foldable glass on the surface of the folding instrument with tape, and use the folding instrument to fold the glass in a book-flipping manner. The folding angle is switched between the two plate surfaces being in contact to 180°, and the folding frequency is 30 times / min. Record the number of times when the glass is damaged.

[0066] (2) Pen-drop performance: Attach 50 μm OCA and 50 μm PET (elastic modulus about 3 - 4 GPa) to the upper and lower surfaces of the UTG. The test table is made of marble. A Chenguang pen with a weight of 12 g and a pen tip diameter of 0.5 mm is freely dropped from a certain height, and the height at which the glass breaks is the pen-drop height.

[0067] The test results are shown in Table 1 below:

[0068] Table 1. Test results of folding times and pen-drop height

[0069] Number of bends Pen drop height (mm) Example 1 Greater than 500,000 42 Example 2 Greater than 500,000 38 Example 3 Greater than 500,000 32 Comparative Example 1 350,000 24 Comparative Example 2 380,000 22 Comparative Example 3 450,000 10

[0070] As mentioned above, the above are only the preferred specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution and inventive concept of the present invention, makes equivalent substitutions or changes, and all should be covered within the protection scope of the present invention.

Claims

1. A preparation process for flexible foldable glass with unequal thicknesses, characterized in that, The method includes the following steps: S1. An etching solution channel for guiding the etching solution to flow through the area to be etched is arranged above the glass to be processed; S2. The etching solution is introduced into the etching solution channel, and after etching, an arc-shaped groove is formed in the area to be etched; S3. The glass to be processed is separated from the etching solution channel, the glass surface with the arc-shaped groove formed is protected against acid, and the other side of the glass is chemically thinned to the target thickness, thus obtaining the unequal-thickness flexible foldable glass; Specifically, S1 is as follows: Two acid-resistant plates are vertically and parallelly placed above the glass to be processed, and the acid-resistant plates and the glass to be processed are connected by a pyrolytic acid-resistant adhesive, that is, an etching solution channel is formed between the two acid-resistant plates; both ends of the acid-resistant plates straddle the glass to be processed, and the distance between the two acid-resistant plates is set according to the width of the area to be etched.

2. The preparation process for flexible foldable glass with unequal thicknesses according to claim 1, characterized in that, In S1, the etching solution channel is arranged between two pieces of glass to be processed that are parallel up and down, and the etching of the two pieces of glass can be realized simultaneously.

3. The preparation process for flexible foldable glass with unequal thicknesses according to claim 1 or 2, characterized in that, In S2, the etching solution pressure is 0.02 - 0.1 kg / cm 2 , the etching solution temperature is 20 - 45 °C, and the etching time is 1 - 30 min.

4. The preparation process for flexible foldable glass with unequal thicknesses according to any one of claims 1 - 3, characterized in that, In S2, the etching solution pressure is 0.02 - 0.05 kg / cm 2 , the etching solution temperature is 25 - 35 °C, and the etching time is 8 - 20 min.

5. The preparation process for flexible foldable glass with unequal thicknesses according to any one of claims 2 - 4, characterized in that, In S3, the glass is separated from the etching solution channel by heating to decompose the adhesive; preferably, the glass surface with the arc-shaped groove formed is protected against acid by covering a pyrolytic acid-resistant film.

6. The preparation process for flexible foldable glass with unequal thicknesses according to any one of claims 1 - 5, characterized in that, In S3, the chemical thinning adopts the top spraying process.

7. The preparation process for flexible foldable glass with unequal thicknesses according to any one of claims 1 - 6, characterized in that, It further includes S4. Chemically strengthening the glass after chemical thinning.

8. A flexible foldable glass with unequal thicknesses, characterized in that, Prepared according to any one of the processes of claims 1-7.

9. The flexible foldable glass with unequal thicknesses according to claim 8, characterized in that, The thickness of the arc-shaped groove part of the unequal-thickness flexible foldable glass is less than the thickness of other parts; the distance from the bottom of the arc-shaped groove to the side away from the groove <0.1 mm; preferably, the distance from the bottom of the groove to the side away from the groove is 0.03 ± 0.005 mm.

Images