High-hardness high-wear-resistance release film and preparation method thereof

Abstract

The invention provides a high-hardness high-wear-resistance release film and a preparation method thereof, the high-hardness high-wear-resistance release film is composed of polyurethane acrylate (PUA) and nano reinforced particles SiO or AlO, when the content of SiO is 28%-32%, the hardness is greater than or equal to 5H, and the wear-resistance loss is less than or equal to 0.8 mg / 1000 times, and when the content of AlO is 38%-42%, the hardness is greater than or equal to 6H, and the wear-resistance loss is less than or equal to 0.5 mg / 1000 times. The preparation method comprises the following steps: pre-dispersing PUA and nanoparticles at 50 DEG C (800-1200 rpm, 30-45 min), carrying out vacuum defoaming (-0.08 to-0.10 MPa, 65-75 DEG C), coating a corona treated PET base material with the obtained product (the coating precision is less than or equal to + / -1.5 [mu] m), carrying out gradient ultraviolet curing in a nitrogen atmosphere, adjusting the wavelength to 320-385 nm and the strength to 80-220 mW / cm in three stages, and finally carrying out hot air curing at 90 DEG C for 25-35 min. Preferably, the coating of the SiO system is 10-15 microns, the curing energy is 28H + 220mJ / cm, the coating of the AlO system is 8-12 microns, and the curing energy is 32H + 280mJ / cm. The hardness and wear resistance of the release film can be improved, and excellent glossiness is kept.

Description

Technical Field

[0001] The present invention relates to the technical field of functional thin film materials, and more specifically, the present invention relates to a high-hardness and high-wear-resistant release film and a preparation method thereof. Background Art

[0002] In the current field of materials science, as an important functional thin film material, the release film is widely used in multiple industries such as electronics, optics, and packaging. The main function of the release film is to prevent material adhesion during the processing process, thereby ensuring the surface quality and processing efficiency of the product. Traditional release films are usually prepared from materials such as polysiloxane. Although they have certain release properties, they have obvious deficiencies in terms of hardness and wear resistance. With the continuous improvement of the requirements for material properties in modern industry, especially in the fields of high-end electronic device manufacturing and high-precision optical element processing, higher requirements are put forward for the hardness and wear resistance of the release film. Although the existing release film technology can meet the basic usage requirements to a certain extent, when facing special requirements such as high hardness and high wear resistance, it often shows problems such as insufficient hardness and poor wear resistance, which limits its application in high-end fields.

[0003] In the process of implementing the embodiments of the present invention, the inventors found that there are at least the following problems or defects in the prior art: The existing release films cannot simultaneously meet high requirements in terms of hardness and wear resistance, especially there are obvious deficiencies in the balance of high hardness and high wear resistance. In addition, the preparation process of traditional release films is complex, the production efficiency is low, and it is difficult to achieve uniform dispersion of nano-enhanced particles, resulting in poor performance uniformity and stability of the release film. Summary of the Invention

[0004] The present invention provides a high-hardness and high-wear-resistant release film and a preparation method thereof.

[0005] In the first aspect of the present invention, a high-hardness and high-wear-resistant release film is provided. The material is composed of polyurethane acrylate (PUA) and nano-enhanced particles, and the nano-enhanced particles are selected from silicon dioxide (SiO2) or aluminum oxide (Al2O3); When the nano-enhanced particle is silicon dioxide (SiO2), in terms of mass percentage, the components of the release film are: PUA: 68% - 72%, SiO2: 28% - 32%, the surface hardness of the release film ≥ 5H, and the mass loss in the Taber wear test ≤ 0.8 mg / 1000 times; When the nano-enhanced particle is aluminum oxide (Al2O3), in terms of mass percentage, the components of the release film are: PUA: 58% - 62%, Al2O3: 38% - 42%, the surface hardness of the release film ≥ 6H, and the mass loss in the Taber wear test ≤ 0.5 mg / 1000 times.

[0006] Further, when the nano-enhanced particles are SiO2, the composition of the release film is: PUA: 69% - 71%, SiO2: 29% - 31%, the peak wavelength of ultraviolet curing is 365 nm, the curing energy density is 350 - 400 mJ / cm², the wet film coating thickness is 10 - 15 μm, and the surface gloss after curing is ≥90 GU.

[0007] Further, when the nano-enhanced particles are Al2O3, the composition of the release film is: PUA: 59% - 61%, Al2O3: 39% - 41%, the peak wavelength of ultraviolet curing is 385 nm, the curing energy density is 450 - 500 mJ / cm², the wet film coating thickness is 8 - 12 μm, and the surface gloss after curing is ≥95 GU.

[0008] In the second aspect of the present invention, a method for preparing a high-hardness and high-wear-resistant release film is provided, which specifically includes the following steps: Step 1: Pre-disperse polyurethane acrylate (PUA) and nano-enhanced particles in a constant temperature environment of 50 ± 2 °C, with a mixing speed of 800 - 1200 rpm and a dispersion time of 30 - 45 min; Step 2: Introduce the premix into a vacuum degassing machine and perform degassing treatment at -0.08 to -0.10 MPa and 65 - 75 °C for 20 - 30 min; Step 3: Use a precision coater to coat the degassed mixture on the surface of a corona-treated PET substrate, and the surface tension of the substrate is ≥50 dyn / cm; Step 4: Perform gradient ultraviolet curing in a nitrogen atmosphere with an oxygen content ≤100 ppm, and the curing intensity is divided into three stages from low to high; Step 5: Post-cure the cured film material in a hot air circulation oven at 90 ± 5 °C for 25 - 35 min.

[0009] Further, in Step 3, a slot die coating head is used, the coating pressure is 0.15 - 0.25 MPa, the substrate running speed is 15 - 25 m / min, and the coating accuracy error is ≤±1.5 μm.

[0010] Further, the gradient ultraviolet curing in Step 4 includes: S41. The first curing stage: the irradiation intensity is 80 - 100 mW / cm², the wavelength is 320 - 340 nm, and the duration is 3 - 5 s; S42. The second curing stage: the irradiation intensity is 120 - 150 mW / cm², the wavelength is 340 - 365 nm, and the duration is 5 - 8 s; S43. The third curing stage: the irradiation intensity is 180 - 220 mW / cm², the wavelength is 365 - 385 nm, and the duration is 8 - 12 s.

[0011] Further, when the nano-enhanced particles are SiO2, the irradiation intensity in the third curing stage is increased by 20% to 25% compared to the second curing stage, and the wavelength range is extended to 385 - 395 nm.

[0012] Further, when the nano-enhanced particles are Al2O3, the proportion of the 365 nm wavelength in the first curing stage is increased to 40% - 50%, and the irradiation intensity in the third curing stage is increased by 150% - 180% compared to the first curing stage.

[0013] Further, defining the wet film coating thickness as H (μm), the total UV energy E (mJ / cm²) satisfies: When the nano-enhanced particles are SiO2, E = 28H + 220, where 10 ≤ H ≤ 15; When the nano-enhanced particles are Al2O3, E = 32H + 280, where 8 ≤ H ≤ 12.

[0014] Further, in the post-curing process in step 5, segmented temperature control is adopted: The first stage: maintain at 80°C ± 2°C for 8 - 10 min; The second stage: maintain at 95°C ± 2°C for 12 - 15 min; The third stage: maintain at 85°C ± 2°C for 5 - 8 min.

[0015] The above embodiments of the present invention have at least the following beneficial effects: The high-hardness and high-wear-resistant release film and its preparation method of the present invention can improve the comprehensive performance of the release film. By using a combination of polyurethane acrylate PUA and nano-enhanced particles (such as silica SiO2 or alumina Al2O3), the release film can not only achieve high hardness and high wear resistance, but also maintain good flexibility and optical properties. When using SiO2 as the reinforcing particles, the surface hardness of the release film can reach ≥5H, and the mass loss in the Taber wear test is ≤0.8 mg / 1000 times; when using Al2O3, the surface hardness can reach ≥6H, and the mass loss in the wear test is ≤0.5 mg / 1000 times. In addition, through an optimized preparation process, such as gradient UV curing and segmented temperature control in post-curing, the internal stress of the release film can be effectively reduced, its adhesion and wear resistance can be improved, and at the same time, the thickness uniformity and optical properties of the release film can be ensured.

[0016] The preparation method of the present invention can also improve production efficiency and product quality. By precisely controlling the pre-dispersion conditions, defoaming treatment, coating accuracy, and UV curing parameters, it can ensure the uniform dispersion of nano-enhanced particles in the polyurethane acrylate (PUA) matrix, forming a dense wear-resistant layer. This uniform dispersion can not only enhance the hardness and wear resistance of the release film, but also improve the stability and consistency of its performance. In addition, the post-curing process with segmented temperature control can further optimize the mechanical properties of the release film, enabling it to exhibit excellent performance in different application scenarios. Therefore, the release film of the present invention and its preparation method can meet the market demand for high-performance release films, and are particularly suitable for fields such as high-end electronic device manufacturing and high-precision optical component processing. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] By reading the following detailed description with reference to the accompanying drawings, the above and other objects, features, and advantages of the exemplary embodiments of the present invention will become readily understood. In the drawings, several embodiments of the present invention are shown by way of illustration and not limitation, wherein: Figure 1 FIG. is a schematic flow chart of a method for preparing a high-hardness and high-wear-resistant release film provided by an embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0018] The following examples are used to specifically describe the preferred embodiments of the present invention. The examples constitute a part of this application and are used together with the embodiments of the present invention to illustrate the principles of the present invention, and are not used to limit the scope of the present invention.

[0019] The object of the present invention is to provide a high-hardness and high-wear-resistant release film and its preparation method. The release film mainly consists of polyurethane acrylate (PUA) and nano-enhanced particles, and the nano-enhanced particles are selected from silicon dioxide (SiO2) or aluminum oxide (Al2O3). When the nano-enhanced particle is SiO2, the composition of the release film is: PUA 68% - 72%, SiO2 28% - 32%, surface hardness ≥ 5H, mass loss in Taber wear test (CS-10 wheel, 500g load) ≤ 0.8 mg / 1000 times; when the nano-enhanced particle is Al2O3, the composition of the release film is: PUA 58% - 62%, Al2O3 38% - 42%, surface hardness ≥ 6H, mass loss in Taber wear test (CS-10 wheel, 500g load) ≤ 0.5 mg / 1000 times.

[0020] It should be noted that the functions of the components in the above release film are as follows: Polyurethane acrylate (PUA): It has a good balance of flexibility and hardness, and can provide the basic mechanical properties and certain wear resistance for the release film.

[0021] Silicon dioxide SiO2: Nanoscale SiO2 particles can effectively enhance the hardness and wear resistance of the release film while maintaining a certain light transmittance.

[0022] Aluminum oxide Al2O3: Nanoscale Al2O3 particles have higher hardness and wear resistance, which can further improve the surface hardness and wear resistance of the release film.

[0023] In the process of preparing the release film, the ratio of polyurethane acrylate PUA to nano-enhanced particles has an important impact on the performance of the release film. Too high or too low content of nano-enhanced particles is not conducive to improving the comprehensive performance of the release film, and it is easy to cause insufficient hardness and wear resistance or decreased flexibility of the release film. In the prior art, the component ratio of the release film is unreasonable, and the influence of different enhanced particles on the performance of the release film is not fully considered.

[0024] In the present invention, the performance of the release film is closely related to the type and content of nano-enhanced particles. When using SiO2 as the enhanced particle, its content in the range of 28% - 32% can ensure that the hardness of the release film reaches above 5H and has good wear resistance; when using Al2O3 as the enhanced particle, the content in the range of 38% - 42% can make the hardness of the release film reach above 6H and has better wear resistance.

[0025] Preferably, when the nano-enhanced particle is SiO2, the components of the release film are: PUA 69% - 71%, SiO2 29% - 31%, the peak wavelength of ultraviolet curing is 365nm, the curing energy density is 350 - 400mJ / cm², the wet film coating thickness is 10 - 15μm, and the surface glossiness (60°) after curing is ≥90GU.

[0026] Preferably, when the nano-enhanced particle is Al2O3, the components of the release film are: PUA 59% - 61%, Al2O3 39% - 41%, the peak wavelength of ultraviolet curing is 385nm, the curing energy density is 450 - 500mJ / cm², the wet film coating thickness is 8 - 12μm, and the surface glossiness (60°) after curing is ≥95GU.

[0027] Preferably, when the nano-enhanced particle is SiO2, the components of the release film are: PUA 70%, SiO2 30%, the peak wavelength of ultraviolet curing is 365nm, the curing energy density is 375mJ / cm², the wet film coating thickness is 12μm, and the surface glossiness (60°) after curing is ≥92GU.

[0028] Preferably, when the nano-enhanced particle is Al2O3, the components of the release film are: PUA 60%, Al2O3 40%, the peak wavelength of ultraviolet curing is 385nm, the curing energy density is 475mJ / cm², the wet film coating thickness is 10μm, and the surface glossiness (60°) after curing is ≥96GU.

[0029] Specifically, in the preparation of the high-hardness and high-wear-resistant release film, the process parameters have a significant impact on the performance of the release film, as follows: (1) Pre-dispersion conditions: The pre-dispersion temperature is 50 ± 2 °C, the mixing speed is 800 - 1200 rpm, and the dispersion time is 30 - 45 min, ensuring that the polyurethane acrylate PUA and the nano-enhanced particles are fully mixed to form a uniform premix. Appropriate pre-dispersion conditions can effectively prevent the agglomeration of nano-particles and improve the performance uniformity of the release film.

[0030] (2) Degassing treatment: Degassing treatment is carried out at -0.08 to -0.10 MPa and 65 - 75 °C for 20 - 30 min to remove the bubbles in the premix and ensure the density and optical properties of the release film. Insufficient degassing will cause bubble defects in the release film, affecting its application performance.

[0031] (3) Coating accuracy: A slot die coater is used, the coating pressure is 0.15 - 0.25 MPa, the substrate running speed is 15 - 25 m / min, and the coating accuracy error is ≤ ±1.5 μm, ensuring the precise control of the wet film coating thickness, and thus affecting the final performance of the release film. High coating accuracy can ensure the uniform thickness of the release film and improve the product quality.

[0032] (4) UV curing: Gradient UV curing is carried out in a nitrogen atmosphere with an oxygen content ≤ 100 ppm, and the curing intensity is divided into three stages from low to high. Gradient curing can effectively reduce the internal stress of the release film and improve its adhesion and wear resistance.

[0033] On the other hand, the present invention provides a method for preparing a high-hardness and high-wear-resistant release film, as Figure 1 shown, including the following steps: Step 1: Pre-disperse the polyurethane acrylate PUA and the nano-enhanced particles in a constant temperature environment of 50 ± 2 °C, with a mixing speed of 800 - 1200 rpm and a dispersion time of 30 - 45 min.

[0034] Step 2: Introduce the premix into a vacuum degassing machine and carry out degassing treatment at -0.08 to -0.10 MPa and 65 - 75 °C for 20 - 30 min.

[0035] Step 3: Use a precision coater to coat the degassed mixture on the surface of the corona-treated PET substrate, and the surface tension of the substrate is ≥ 50 dyn / cm.

[0036] Step 4: Carry out gradient UV curing in a nitrogen atmosphere with an oxygen content ≤ 100 ppm, and the curing intensity is divided into three stages from low to high.

[0037] Step 5: Post-cure the cured film material in a hot air circulation oven at 90 ± 5°C for 25 - 35 min.

[0038] Specifically, in Step 1, the pre-dispersion temperature is controlled at 50 ± 2°C, the mixing rotation speed is 800 - 1200 rpm, and the dispersion time is 30 - 45 min to ensure that the polyurethane acrylate PUA and the nano-enhanced particles are fully mixed to form a uniform and stable premix.

[0039] Specifically, in Step 2, vacuum degassing is carried out at -0.08 to -0.10 MPa and 65 - 75°C for 20 - 30 min to effectively remove the bubbles in the premix and ensure the quality of the release film.

[0040] Specifically, in Step 3, a slot die coater is used, the coating pressure is 0.15 - 0.25 MPa, the substrate running speed is 15 - 25 m / min, and the coating accuracy error is ≤ ±1.5 μm to ensure the precise control of the wet film coating thickness.

[0041] Specifically, in Step 4, the gradient UV curing includes: S41. The first curing stage: the irradiation intensity is 80 - 100 mW / cm², the wavelength is 320 - 340 nm, and the duration is 3 - 5 s.

[0042] S42. The second curing stage: the irradiation intensity is 120 - 150 mW / cm², the wavelength is 340 - 365 nm, and the duration is 5 - 8 s.

[0043] S43. The third curing stage: the irradiation intensity is 180 - 220 mW / cm², the wavelength is 365 - 385 nm, and the duration is 8 - 12 s.

[0044] When the nano-enhanced particle is SiO2, the irradiation intensity in the third curing stage is increased by 20% - 25% compared with the second curing stage, and the wavelength range is extended to 385 - 395 nm.

[0045] When the nano-enhanced particle is Al2O3, the proportion of the 365 nm wavelength in the first curing stage is increased to 40% - 50%, and the irradiation intensity in the third curing stage is increased by 150% - 180% compared with the first curing stage.

[0046] Define the wet film coating thickness as H (μm), and the total UV energy E (mJ / cm²) satisfies: When the nano-enhanced particle is SiO2, E = 28H + 220, where 10 ≤ H ≤ 15.

[0047] When the nano-enhanced particle is Al2O3, E = 32H + 280, where 8 ≤ H ≤ 12.

[0048] In Step 5, the post-cure process adopts segmented temperature control: The first stage: maintain at 80°C ± 2°C for 8 - 10 min.

[0049] The second stage: maintain at 95°C ± 2°C for 12 - 15 min.

[0050] The third stage: maintain at 85°C ± 2°C for 5 - 8 min.

[0051] In the preparation method of the present invention, by precisely controlling each process parameter, the high performance of the release film is achieved. In particular, gradient ultraviolet curing and post-curing segmented temperature control effectively improve the hardness, wear resistance and adhesion of the release film.

[0052] Example 1-1 The object of the present invention is to provide a high-hardness and high-wear-resistant release film and its preparation method. The release film is composed of polyurethane acrylate PUA and nano-enhanced particles SiO2, and the components are: PUA 70%, SiO2 30%. Its surface hardness ≥ 5H, and the mass loss in the Taber wear test (CS-10 wheel, 500 g load) ≤ 0.8 mg / 1000 times.

[0053] The preparation method of the high-hardness and high-wear-resistant release film includes the following steps: Step 1: Pre-disperse polyurethane acrylate PUA and nano-enhanced particles SiO2 in a constant temperature environment of 50°C, with a mixing speed of 1000 rpm and a dispersion time of 35 min.

[0054] Step 2: Import the premixed material into a vacuum degassing machine and perform degassing treatment for 25 min under the conditions of -0.09 MPa and 70°C.

[0055] Step 3: Use a precision coater to coat the degassed mixed liquid on the surface of the corona-treated PET substrate, and the surface tension of the substrate ≥ 50 dyn / cm. When coating, a slit coating head is used, the coating pressure is 0.2 MPa, the substrate running speed is 20 m / min, the coating accuracy error ≤ ±1.0 μm, and the wet film coating thickness is 12 μm.

[0056] Step 4: Perform gradient ultraviolet curing in a nitrogen atmosphere with an oxygen content ≤ 100 ppm. The gradient ultraviolet curing includes: S41. The first curing stage: irradiation intensity 90 mW / cm², wavelength 330 nm, duration 4 s.

[0057] S42. The second curing stage: irradiation intensity 135 mW / cm², wavelength 350 nm, duration 6 s.

[0058] S43. The third curing stage: the irradiation intensity is 200 mW / cm², the wavelength is 385 - 395 nm, and the duration is 10 s. The total UV energy E = 28×12 + 220 = 544 mJ / cm².

[0059] Step 5: Post-cure the cured film material in a hot air circulation oven at 90°C for 30 min. The post-curing process is temperature-controlled in segments: The first stage: maintain at 80°C for 9 min.

[0060] The second stage: maintain at 95°C for 13 min.

[0061] The third stage: maintain at 85°C for 6 min.

[0062] The surface hardness of the obtained release film reaches 5H, the mass loss in the Taber abrasion test (CS-10 wheel, 500 g load) is 0.5 mg / 1000 times, and the surface glossiness (60°) is 92 GU.

[0063] Example 1-2 The composition of the release film in this example is: PUA 69%, SiO2 31%. The remaining preparation methods and process parameters are the same as those in Example 1-1.

[0064] The surface hardness of the obtained release film reaches 5H, the mass loss in the Taber abrasion test (CS-10 wheel, 500 g load) is 0.6 mg / 1000 times, and the surface glossiness (60°) is 91 GU.

[0065] Example 1-3 The composition of the release film in this example is: PUA 71%, SiO2 29%. The remaining preparation methods and process parameters are the same as those in Example 1-1.

[0066] The surface hardness of the obtained release film reaches 5H, the mass loss in the Taber abrasion test (CS-10 wheel, 500 g load) is 0.7 mg / 1000 times, and the surface glossiness (60°) is 93 GU.

[0067] Example 2-1 The object of the present invention is to provide a high-hardness and high-abrasion-resistant release film and its preparation method. The release film is composed of polyurethane acrylate PUA and nano-enhanced particles Al2O3, and the composition is: PUA 60%, Al2O3 40%. Its surface hardness ≥ 6H, and the mass loss in the Taber abrasion test (CS-10 wheel, 500 g load) ≤ 0.5 mg / 1000 times.

[0068] The preparation method of the high-hardness and high-abrasion-resistant release film includes the following steps: Step 1: Pre-disperse polyurethane acrylate (PUA) and nano-enhanced particles Al2O3 in a constant temperature environment of 50°C, with a mixing speed of 1000 rpm and a dispersion time of 35 min.

[0069] Step 2: Introduce the premix into a vacuum degassing machine and perform degassing treatment for 25 min under the conditions of -0.09 MPa and 70°C.

[0070] Step 3: Coat the degassed mixture on the surface of the corona-treated PET substrate using a precision coater. The surface tension of the substrate is ≥50 dyn / cm. A slot die coater head is used during coating, with a coating pressure of 0.2 MPa, a substrate running speed of 20 m / min, a coating accuracy error of ≤±1.0 μm, and a wet film coating thickness of 10 μm.

[0071] Step 4: Perform gradient ultraviolet curing in a nitrogen atmosphere with an oxygen content of ≤100 ppm. The gradient ultraviolet curing includes: S41, First curing stage: Irradiation intensity is 85 mW / cm², wavelength is 320 - 340 nm (where the proportion of 365 nm wavelength is 45%), and the duration is 4 s.

[0072] S42, Second curing stage: Irradiation intensity is 130 mW / cm², wavelength is 340 - 365 nm, and the duration is 6 s.

[0073] S43, Third curing stage: Irradiation intensity is 210 mW / cm², wavelength is 365 - 385 nm, and the duration is 10 s. The total ultraviolet energy E = 32×10 + 280 = 600 mJ / cm².

[0074] Step 5: Post-cure the cured film in a hot air circulation oven at 90°C for 30 min. The post-curing process is temperature-controlled in segments: First stage: Maintain at 80°C for 9 min.

[0075] Second stage: Maintain at 95°C for 13 min.

[0076] Third stage: Maintain at 85°C for 6 min.

[0077] The surface hardness of the obtained release film reaches 6H, the mass loss in the Taber abrasion test (CS-10 wheel, 500 g load) is 0.3 mg / 1000 times, and the surface gloss (60°) is 96 GU.

[0078] Example 2-2 The composition of the release film in this example is: PUA 59%, Al2O3 41%. The remaining preparation methods and process parameters are the same as those in Example 2-1.

[0079] The surface hardness of the obtained release film reaches 6H, the mass loss in the Taber abrasion test (CS-10 wheel, 500g load) is 0.35mg / 1000 times, and the surface gloss (60°) is 95GU.

[0080] Example 2-3 The composition of the release film in this example is: 61% PUA and 39% Al2O3. The remaining preparation methods and process parameters are the same as those in Example 2-1.

[0081] The surface hardness of the obtained release film reaches 6H, the mass loss in the Taber abrasion test (CS-10 wheel, 500g load) is 0.4mg / 1000 times, and the surface gloss (60°) is 95GU.

[0082] Comparative Example 1 The composition of the release film in this comparative example is: 75% PUA and 25% SiO2. The remaining preparation methods and process parameters are the same as those in Example 1-1.

[0083] The surface hardness of the obtained release film is 4H, the mass loss in the Taber abrasion test (CS-10 wheel, 500g load) is 1.0mg / 1000 times, and the surface gloss (60°) is 85GU. The performance is significantly lower than that of the examples of the present invention.

[0084] Comparative Example 2 In this comparative example, step 4 of gradient UV curing is omitted in the preparation method, and a single curing condition is directly adopted: irradiation intensity 150mW / cm², wavelength 365nm, and duration 10s. The remaining conditions are the same as those in Example 1-1.

[0085] The surface hardness of the obtained release film is 3H, the mass loss in the Taber abrasion test (CS-10 wheel, 500g load) is 1.2mg / 1000 times, and the surface gloss (60°) is 80GU. The performance is significantly lower than that of the examples of the present invention.

[0086] Comparative Example 3 In this comparative example, the post-curing process in step 5 is omitted in the preparation method. The remaining conditions are the same as those in Example 1-1.

[0087] The surface hardness of the obtained release film is 4H, the mass loss in the Taber abrasion test (CS-10 wheel, 500g load) is 0.9mg / 1000 times, and the surface gloss (60°) is 88GU. The performance is significantly lower than that of the examples of the present invention.

[0088] The organizational structure determines the performance. For the high-hardness and high-wear-resistant release film obtained by the preparation method of the present invention, the nano-enhanced particles are uniformly dispersed in the polyurethane acrylate (PUA) matrix, forming a dense wear-resistant layer. Its hardness and wear resistance are significantly superior to the prior art and other comparative solutions, solving the technical problem of insufficient hardness and wear resistance of traditional release films and meeting the market demand for high-performance release films.

[0089] 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 changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention.

Claims

1. A high hardness and high wear resistance release film, characterized in that: The release film is composed of polyurethane acrylate PUA and nano-reinforced particles, and the nano-reinforced particles are selected from silicon dioxide SiO2 or aluminum oxide Al2O3; When the nano-reinforced particles are silicon dioxide SiO2, the components of the release film are, by mass percentage, PUA: 68% to 72%, SiO2: 28% to 32%, the surface hardness of the release film is ≥5H, and the mass loss of the Taber wear test is ≤0.8mg / 1000 times; When the nano-reinforced particles are aluminum oxide Al2O3, the components of the release film are, by mass percentage, PUA: 58% to 62%, Al2O3: 38% to 42%, the surface hardness of the release film is ≥6H, and the mass loss in the Taber wear test is ≤0.5mg / 1000 times.

2. The release film according to claim 1, characterized in that: When the nano-reinforced particles are SiO2, the components of the release film are: PUA: 69% to 71%, SiO2: 29% to 31%, the UV curing peak wavelength is 365nm, the curing energy density is 350 to 400mJ / cm², the wet film coating thickness is 10 to 15μm, and the surface gloss after curing is ≥90GU.

3. The release film according to claim 1, characterized in that: When the nano-reinforced particles are Al2O3, the components of the release film are: PUA: 59% to 61%, Al2O3: 39% to 41%, the UV curing peak wavelength is 385nm, the curing energy density is 450 to 500mJ / cm², the wet film coating thickness is 8 to 12μm, and the surface gloss after curing is ≥95GU.

4. A method for preparing a high-hardness and high-wear-resistant release film, using the release film according to claims 1 to 3, characterized in that: The following steps are involved: Step 1: pre-disperse polyurethane acrylate PUA and nano-reinforced particles in a constant temperature environment of 50±2°C, with a mixing speed of 800-1200 rpm and a dispersion time of 30-45 min; Step 2: introduce the premix into a vacuum degassing machine and degas for 20 to 30 minutes at -0.08 to -0.10 MPa and 65 to 75°C; Step 3: Use a precision coating machine to coat the degassed mixed solution on the surface of the corona-treated PET substrate, and the surface tension of the substrate is ≥50dyn / cm; Step 4: Gradient UV curing is performed in a nitrogen atmosphere with an oxygen content of ≤100ppm. The curing intensity is divided into three stages from low to high; Step 5: Post-cure the cured film material in a hot air circulation oven at 90±5°C for 25 to 35 minutes.

5. The preparation method according to claim 4, characterized in that: In the step 3, a slit coating head is used, the coating pressure is 0.15-0.25 MPa, the substrate speed is 15-25 m / min, and the coating accuracy error is ≤±1.5 μm.

6. The preparation method according to claim 4, characterized in that: The gradient UV curing in step 4 includes: S41, first curing stage: irradiation intensity 80 ~ 100mW / cm², wavelength 320 ~ 340nm, duration 3 ~ 5s; S42, second curing stage: irradiation intensity 120 ~ 150mW / cm², wavelength 340 ~ 365nm, duration 5 ~ 8s; S43, the third curing stage: irradiation intensity 180 ~ 220mW / cm², wavelength 365 ~ 385nm, duration 8 ~ 12s.

7. The preparation method according to claim 6, characterized in that: When the nano-reinforced particles are SiO2, the irradiation intensity in the third curing stage is increased by 20% to 25% compared with the second curing stage, and the wavelength range is extended to 385 to 395 nm.

8. The preparation method according to claim 6, characterized in that: When the nano-reinforced particles are Al2O3, the proportion of 365nm wavelength is increased to 40% to 50% in the first curing stage, and the irradiation intensity in the third curing stage is increased by 150% to 180% compared with the first curing stage.

9. The preparation method according to claim 6, characterized in that: Define the wet film coating thickness as H, and the total UV energy E satisfies: When the nano-reinforced particles are SiO2, E = 28H + 220, where 10 ≤ H ≤ 15; When the nano-reinforced particles are Al2O3, E=32H+280, where 8≤H≤12.

10. The preparation method according to claim 4, characterized in that: The post-curing process in step 5 adopts segmented temperature control: Stage 1: 80℃±2℃ for 8-10min; Stage 2: 95℃±2℃ for 12-15min; The third stage: maintain 85℃±2℃ for 5 to 8 minutes.

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