A warp-free and impact-resistant foldable glass cover plate and its preparation method

Abstract

The present invention discloses a warpage-free and impact-resistant foldable glass cover plate. The glass cover plate includes, from top to bottom: a hard coating of 10-15 μm, an impact-resistant coating of 25-35 μm, flexible glass, and a warpage-resistant coating of 5-10 μm. Its preparation method includes the following steps: S1. Coating an impact-resistant coating material on the surface of the flexible glass and curing it to obtain flexible glass with an impact-resistant coating; S2. Coating a hard coating material on the surface of the impact-resistant coating and curing it to obtain flexible glass with a double-layer coating; S3. Coating a warpage-resistant coating material on the surface of the flexible glass without the coating material and curing it. The foldable glass cover plate can be applied to foldable screen mobile phones, and has excellent properties such as good tactile feel, light transmittance, bendability, and impact resistance.

Description

Technical Field

[0001] The present invention belongs to the field of flexible glass preparation, and particularly relates to a warpage-free and impact-resistant foldable glass cover plate and a preparation method thereof. Background Art

[0002] In recent years, foldable screen mobile phones have developed rapidly. One of the key technologies of foldable screens lies in the screen material. The primary generation of foldable screens uses CPI as the cover plate material, which has defects such as screen creases and black screens, becoming the main pain points of foldable screen mobile phones. Currently, UTG has become the optimal choice for foldable screen cover plates. However, UTG cannot be directly applied to foldable mobile phone cover plates. The main reasons are that UTG is thin, fragile, and prone to hurting people, has low strength, and poor impact resistance. Therefore, when applying UTG, a layer of PET or CPI needs to be laminated to protect UTG. However, the friction resistance, hardness, and feel of PET and CPI cannot compare with those of glass, and problems such as a large warpage degree exist in the laminated UTG. Summary of the Invention

[0003] Based on the above technical problems, the present invention combines flexible glass with a multi-layer coating material to obtain a warpage-free and impact-resistant foldable glass cover plate. The foldable glass cover plate can be applied to foldable screen mobile phones, and has excellent properties such as good tactile feel, light transmittance, bendability, and impact resistance. At the same time, a preparation method thereof is provided, and the method is simple and can be flexibly adjusted according to requirements.

[0004] The specific solution of the present invention is as follows

[0005] One of the purposes of the present invention is to provide a warpage-free and impact-resistant foldable glass cover plate, which includes, from top to bottom: a hard coating of 10-15 μm, an impact-resistant coating of 25-35 μm, flexible glass, and a warpage-resistant coating of 5-10 μm.

[0006] Preferably, the hard coating material is a hexa-functional polyurethane acrylate resin.

[0007] Preferably, the hard coating material is a fluorine-modified polyurethane acrylate resin.

[0008] The hard coating of the present invention uses a hexa-functional acrylate resin, which has a high solid content, and the coating has characteristics such as high weather resistance, high elasticity, high hardness, wear resistance, and scratch resistance; preferably, it is a fluorine-modified polyurethane acrylate resin, which can increase the modulus, strength, and hardness. The top layer of the foldable glass cover plate of the present invention is a hard coating. During an external impact, the hard coating uses its own tensile deformation to convert the impact kinetic energy into its own elastic potential energy, and dissipates the energy to both sides by relying on its own tensile deformation, thereby achieving the consumption of most of the energy. When selecting the hard coating material, increasing the functional groups of the hard coating resin and improving the crosslinking density can achieve a better impact resistance effect.

[0009] Preferably, the impact-resistant coating material is a resin damping material; more preferably, the resin damping material is selected from any one of polyurethane, acrylic resin, and phenolic resin.

[0010] An impact-resistant coating is provided between the hard coating and the flexible glass in the present invention. Using a resin damping material as the impact-resistant coating material, it has the characteristics of low modulus, high resilience, and impact resistance. After most of the energy is consumed by the hard coating, the residual energy causes local deformation of the hardened layer. To prevent this deformation from being directly transmitted to the flexible glass, a high-elastic impact-resistant coating with a lower modulus is added between the hardened layer and the flexible glass. The impact-resistant coating can absorb and convert the energy transmitted from the upper layer in the form of damping into heat energy by its own deformation, and at the same time, it can also prevent the transmission of the deformation of the hardened coating.

[0011] Preferably, the warpage-resistant coating material is a tri-functional polyurethane acrylate resin.

[0012] Preferably, the flexible glass is UTG with a thickness of 30 - 70 μm.

[0013] The second object of the present invention is to provide a method for preparing a warp-free and impact-resistant foldable glass cover plate, including the following steps: S1. Coating an impact-resistant coating material on the surface of the flexible glass and curing it to obtain a flexible glass with an impact-resistant coating; S2. Coating a hard coating material on the surface of the impact-resistant coating and curing it to obtain a flexible glass with a double-layer coating; S3. Coating a warpage-resistant coating material on the surface of the flexible glass without the coating material and curing it to obtain the product.

[0014] Preferably, in S1, S2, and S3, the solvent is first volatilized by a heating cycle drying method for pre-curing, and then the coating is further cured by a UV lamp.

[0015] Preferably, the pre-curing temperature is 70 - 80 °C, and the pre-curing time is 10 - 30 min; for further curing with a UV lamp, the energy of the UV lamp is 500 - 700 mj / cm 2 , and the curing time is 0.5 - 2 min.

[0016] Preferably, the coating method is selected from any one of spraying, roll coating, and slot coating.

[0017] The beneficial effects of the present invention are as follows:

[0018] The foldable glass cover plate of the present invention shows more excellent bending properties and additional characteristics by coating multiple layers of coating materials on the surface of the flexible glass. Specifically as follows

[0019] 1) Touch feel: The top layer of the foldable glass cover plate of the present invention is a hard coating, and its surface performance is close to the smooth texture of glass, making the touch feel of the glass cover plate closer to that of a straight smartphone that users are accustomed to; 2) Light transmittance: The light transmittance of PET or CPI is generally less than 90%, while the foldable glass cover plate of the present invention has better light transmittance, with a light transmittance exceeding 90%; 3) Protection: The foldable glass cover plate of the present invention has high hardness, impact resistance, and scratch resistance, with better protection; 4) The UTG after coating can achieve crease-free folding, reducing the warping phenomenon of the UTG.

[0020] The present invention also provides a method for preparing the foldable glass cover plate. Compared with the currently widely used film pasting process, it is simple to operate, has high efficiency, and can be flexibly adjusted according to product design. Description of the Drawings

[0021] Figure 1 It is a schematic structural diagram of the foldable glass cover plate of the present invention. Detailed Embodiments

[0022] Next, the technical solutions of the present invention will be described in detail through specific embodiments. However, it should be clearly stated that these embodiments are used for illustration purposes only and are not to be construed as limiting the scope of the present invention.

[0023] Embodiment 1

[0024] An impact-resistant and warp-resistant foldable glass cover plate. The glass cover plate includes, from top to bottom: a 12-μm hard coating, a 30-μm impact-resistant coating, a 30-μm UTG, and an 8-μm warp-resistant coating;

[0025] Among them, the hard coating material is fluorine-modified polyurethane acrylate resin; the impact-resistant coating material is polyurethane resin; the warp-resistant coating material is tri-functional polyurethane acrylate resin.

[0026] Its preparation method includes the following steps:

[0027] S1. Prepare flexible glass with an impact-resistant coating

[0028] Cleaning and covering with a high-temperature-resistant film: First, use a 4.2% potassium hydroxide aqueous solution at a temperature of 53°C to clean the surface of the UTG, then use pure water to clean it and soak it for 50 minutes, and then heat and dry it to ensure that the UTG is free of dirt, oil, and dirt spots; use a film laminator to evenly cover the front and back sides of the UTG with a high-temperature-resistant film, requiring that the surface of the high-temperature-resistant film has no wrinkles, no bubbles, and no damage;

[0029] Coating the impact-resistant coating material: First, tear off the high-temperature-resistant film on the surface of the glass that needs to be coated, and ensure that there is no residual glue and no dirt spots when tearing the film on the coating surface; then use the slit coating method to evenly coat the polyurethane resin on the UTG. After coating, there is no dirt, no bubbles, and no residual glue on the front and back sides;

[0030] Curing treatment: First, adopt the heating cycle drying method to pre-cure for 14 min at 70 °C; then use a UV lamp to further cure the coating, and set the light energy to 600 mj / cm 2 and cure for 1.63 min;

[0031] S2. Prepare flexible glass with a double-layer coating

[0032] Coat the hard coating material: Use the slot coating method to evenly coat the fluorine-modified polyurethane acrylate resin on the impact-resistant coating. After coating, there is no dirt, no bubbles, and no residual glue on the front and back sides;

[0033] Curing treatment: First, adopt the heating cycle drying method to pre-cure for 15 min at 75 °C. After curing, there are no dirt spots, no residual glue, it is resistant to solvent wiping, the film thickness is uniform ≤ 3%, and the adhesion is 5B; then use a UV lamp to further cure the coating, adjust the light energy to 650 mj / cm 2 and the curing time is 1.4 min;

[0034] S3. Coat the anti-warpage coating material

[0035] Coat the anti-warpage coating material: First, tear off the high-temperature resistant film on the surface of the UTG without the coating material. Ensure that there is no residual glue and no dirt spots when tearing the film on the coating surface; cover the other side with a high-temperature resistant film for protection, and then adopt the slot coating method to evenly coat the tri-functional amino acid acrylate resin on the UTG. After coating, there is no dirt, no bubbles, and no residual glue on the front and back sides;

[0036] Curing treatment: First, adopt the heating cycle drying method to pre-cure for 15 min at 75 °C. After curing, there are no dirt spots, no residual glue, it is resistant to solvent wiping, the film thickness is uniform ≤ 3%, and the adhesion is 5B; then use a UV lamp to further cure the coating, adjust the light energy to 650 mj / cm 2 and the curing time is 1.4 min;

[0037] Remove the high-temperature resistant film, wash with pure water, and heat and dry to ensure that the product has no dirt, no oil stain, and no dirt spots.

[0038] Example 2

[0039] A warp-free and impact-resistant foldable glass cover plate, which from top to bottom includes: a hard coating of 10 μm, an impact-resistant coating of 25 μm, a UTG of 40 μm, and an anti-warpage coating of 5 μm;

[0040] Among them, the hard coating material is fluorine-modified polyurethane acrylate resin; the impact-resistant coating material is acrylate resin; the anti-warpage coating material is tri-functional polyurethane acrylate resin.

[0041] Its preparation method includes the following steps:

[0042] S1. Preparation of flexible glass with an impact-resistant coating

[0043] Cleaning and coating with a high-temperature resistant film: First, clean the surface of the UTG with a 4.8% potassium hydroxide aqueous solution at a temperature of 50°C, then clean it with pure water and soak for 48 minutes, and then heat and dry to ensure that the product has no dirt, no oil stain, and no dirty spots; use a film laminator to evenly coat the high-temperature resistant film on both sides of the UTG, requiring that the surface of the high-temperature resistant film has no wrinkles, no bubbles, and no damage;

[0044] Coating the impact-resistant coating material: First, tear off the high-temperature resistant film on the surface of the glass that needs to be coated, and ensure that there is no residual glue and no dirty spots when tearing the film on the coating surface; then use the slit coating method to evenly coat the acrylic resin on the UTG, and there is no dirt, no bubbles, and no residual glue on the front and back after coating;

[0045] Curing treatment: First, use the heating cycle drying method to pre-cure at 78°C for 14 minutes; then use a UV lamp to further cure the coating, set the light energy to 660 mj / cm 2 and cure for 1.5 minutes;

[0046] S2. Preparation of flexible glass with a double-layer coating

[0047] Coating the hard coating material: Use the slit coating method to evenly coat the fluorine-modified polyurethane acrylate resin on the impact-resistant coating, and there is no dirt, no bubbles, and no residual glue on the front and back after coating;

[0048] Curing treatment: First, use the heating cycle drying method to pre-cure at 75°C for 15 minutes, and there are no dirty spots, no residual glue, solvent-resistant wiping, the film thickness is uniform ≤ 3%, and the adhesion is 5B after curing; then use a UV lamp to further cure the coating, adjust the light energy to 700 mj / cm 2 and the curing time is 1.7 minutes;

[0049] S3. Coating the anti-warpage coating material

[0050] Coating the anti-warpage coating material: First, tear off the high-temperature resistant film on the surface of the UTG without the coating material, and ensure that there is no residual glue and no dirty spots when tearing the film on the coating surface; protect the other side by coating with a high-temperature resistant film, and then use the slit coating method to evenly coat the tri-functional amino acid acrylate resin on the UTG, and there is no dirt, no bubbles, and no residual glue on the front and back after coating;

[0051] Curing treatment: First, use the heating cycle drying method to pre-cure at 75°C for 15 minutes, and there are no dirty spots, no residual glue, solvent-resistant wiping, the film thickness is uniform ≤ 3%, and the adhesion is 5B after curing; then use a UV lamp to further cure the coating, adjust the light energy to 700 mj / cm 2 and the curing time is 1.7 minutes;

[0052] Remove the high-temperature resistant film, wash with pure water, heat and dry to ensure that the product has no dirt, no oil stain, and no dirty spots.

[0053] Example 3

[0054] A warp-free and impact-resistant foldable glass cover plate, which from top to bottom includes: a hard coating of 12 μm, an impact-resistant coating of 25 μm, UTG of 50 μm, and a warp-resistant coating of 10 μm;

[0055] Among them, the hard coating material is fluorine-modified polyurethane acrylate resin; the impact-resistant coating material is phenolic resin; the warp-resistant coating material is tri-functional polyurethane acrylate resin.

[0056] Its preparation method includes the following steps:

[0057] S1. Prepare flexible glass with an impact-resistant coating

[0058] Cleaning and covering with high-temperature resistant film: First, use a 5.2% potassium hydroxide aqueous solution at a temperature of 48 °C to clean the surface of UTG, then use pure water to clean and soak for 52 minutes, and then heat and dry to ensure that the product has no dirt, no oil stain, and no dirty spots; Use a film laminating machine to evenly cover the front and back of UTG with a high-temperature resistant film, requiring that the surface of the high-temperature resistant film has no wrinkles, no bubbles, and no damage;

[0059] Coating the impact-resistant coating material: First, tear off the high-temperature resistant film on the surface of the glass that needs to be coated, and ensure no residual glue and no dirty spots when tearing the film on the coating surface; Then use the spraying coating method to evenly coat phenolic resin on UTG, and there should be no dirt, no bubbles, and no residual glue on the front and back after coating;

[0060] Curing treatment: First, use the heating cycle drying method to pre-cure at 72 °C for 15 minutes; Then use a UV lamp to further cure the coating, set the light energy at 580 mj / cm 2 and cure for 1.8 minutes below;

[0061] S2. Prepare flexible glass with a double-layer coating

[0062] Coating the hard coating material: Use the spraying method to evenly coat fluorine-modified polyurethane acrylate resin on the impact-resistant coating, and there should be no dirt, no bubbles, and no residual glue on the front and back after coating;

[0063] Curing treatment: First, use the heating cycle drying method to pre-cure at 75 °C for 15 minutes, and there should be no dirty spots, no residual glue, solvent-resistant wiping, film thickness uniformity ≤ 3%, and adhesion of 5B after curing; Then use a UV lamp to further cure the coating, adjust the light energy to 620 mj / cm 2 and the curing time is 1.5 minutes;

[0064] S3. Coating the anti-warpage coating material

[0065] Coating the anti-warpage coating material: First, tear off the high-temperature resistant film on the surface of the UTG without the coating material. When tearing the film on the coating surface, ensure that there is no residual glue and no dirt. Protect the other side by covering it with a high-temperature resistant film. Then, use the spraying method to evenly coat the triglycine acrylate resin on the UTG. After coating, there should be no dirt, no bubbles, and no residual glue on both the front and back sides;

[0066] Curing treatment: First, use the heating cycle drying method to pre-cure at 75°C for 15 minutes. After curing, there should be no dirt, no residual glue, it should be resistant to solvent wiping, the film thickness should be uniform ≤ 3%, and the adhesion should be 5B. Then, use a UV lamp to further cure the coating, adjust the light energy to 620 mj / cm 2 , and the curing time is 1.5 minutes;

[0067] Remove the high-temperature resistant film, wash it with pure water, and heat it for drying to ensure that the product has no dirt, no oil stain, and no dirt spots.

[0068] Comparative Example 1

[0069] A foldable glass cover plate is prepared according to the following method:

[0070] S1. Use an automatic alignment turning laminator to laminate OCA on the upper surface of the UTG (with a thickness of 40 μm) at a temperature of 23°C, the upper roller pressure is 0.35 MPa, the lower roller pressure is 0.35 MPa, the lamination speed is 40 mm / s. After lamination, ensure that the product has no dirt, no dirt spots, no wrinkles, no bubbles, and the lamination is not misaligned;

[0071] S2. Use a vacuum degassing machine to degas the OCA laminated on the upper surface of the UTG. The degassing pressure is 0.55 MPa, the degassing temperature is 50°C, the degassing time is 30 minutes, and the degassing method is to heat first and then pressurize. Ensure that the product after lamination has no dirt, no dirt spots, no wrinkles, no bubbles;

[0072] S3. Use an automatic alignment turning laminator to laminate OCA on the lower surface of the UTG at a temperature of 23°C, the upper pressure roller pressure is 0.35 MPa, the lower pressure roller pressure is 0.35 MPa, the lamination speed is 40 mm / s. After lamination, ensure that the product has no dirt, no dirt spots, no wrinkles, no bubbles, and the lamination is not misaligned;

[0073] S4. Use a vacuum degassing machine to degas the OCA laminated on the lower surface of the UTG. The degassing pressure is 0.55 MPa, the degassing temperature is 50°C, the degassing time is 30 minutes, and the degassing method is to heat first and then pressurize. Ensure that the product after lamination has no dirt, no dirt spots, no wrinkles, no bubbles;

[0074] S5. Use an automatic alignment flipper laminator to laminate CPI / PET on the upper surface of the UTG at a temperature of 23°C, with the pressure of the upper pressure roller being 0.35 MPa and the pressure of the lower pressure roller being 0.35 MPa. The lamination speed is 40 mm / s. After lamination, ensure that the product has no dirt, no dirty spots, no wrinkles, no bubbles, and no misalignment in lamination.

[0075] S6. Use a vacuum degassing machine to degas the CPI / PET laminated on the upper surface of the UTG. The degassing pressure is 0.55 MPa, the degassing temperature is 50°C, and the degassing time is 30 minutes. The degassing method is to heat first and then pressurize. After lamination, ensure that the product has no dirt, no dirty spots, no wrinkles, and no bubbles.

[0076] Test the performance of the foldable glass cover plates described in the above Examples 1-3 and Comparative Example 1. The test results are shown in Table 1 below:

[0077] Table 1. Test Results of the Performance of the Foldable Glass Cover Plate

[0078]

[0079] 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 by the protection scope of the present invention.

Claims

1. An impact-resistant foldable glass cover plate without warping, characterized in that, The glass cover plate consists of the following layers from top to bottom: a hard coating of 10-15 μm, an impact-resistant coating of 25-35 μm, a flexible glass, and a warpage-resistant coating of 5-10 μm; the impact-resistant coating material is a resin damping material; the resin damping material is selected from any one of polyurethane, acrylic resin, and phenolic resin; the hard coating material is a fluorine-modified polyurethane acrylate resin; the warpage-resistant coating material is a tri-functional polyurethane acrylate resin.

2. The impact-resistant foldable glass cover plate without warping according to claim 1, characterized in that, The flexible glass is UTG with a thickness of 30-70 μm.

3. A method for preparing an impact-resistant foldable glass cover plate without warping according to claim 1 or 2, characterized in that, It includes the following steps: S1. Coating the impact-resistant coating material on the surface of the flexible glass and curing it to obtain the flexible glass with an impact-resistant coating; S2. Coating the hard coating material on the surface of the impact-resistant coating and curing it to obtain the flexible glass with a double-layer coating; S3. Coating the warpage-resistant coating material on the surface of the flexible glass without the coating material and curing it to obtain the product.

4. The method for preparing an impact-resistant foldable glass cover plate without warping according to claim 3, characterized in that, In S1, S2, and S3, the solvent is volatilized by a heating cycle drying method for pre-curing first, and then the coating is further cured by a UV lamp.

5. The method for preparing an impact-resistant foldable glass cover plate without warping according to claim 4, characterized in that, The pre-curing temperature is 70 - 80 °C, and the pre-curing time is 10 - 30 min; further curing is carried out using a UV lamp, and the energy of the UV lamp is 500 - 700 mj / cm 2 , and the curing time is 0.5 - 2 min.

6. The method for preparing an impact-resistant foldable glass cover plate without warping according to claim 3 or 4, characterized in that, The coating method is selected from any one of spraying, roll coating, and slot coating.

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