Optical functional film and preparation process thereof

Abstract

The invention discloses an optical functional film and a preparation process thereof, and relates to the technical field of optical films. The preparation method comprises the following steps: adding bio-based polyurethane acrylate and a degradable plasticizer into an environment-friendly organic solvent, uniformly stirring, sequentially adding nano silicon dioxide, a photoinitiator, a dispersing agent and a flatting agent, and continuously stirring to form a uniform optical functional layer solution; uniformly coating the prepared optical functional layer solution on the release layer by using a coating machine; the release layer coated with the optical function layer solution is sent into a curing device to be cured, and the surface of the cured optical function layer is coated with a pressure-sensitive adhesive layer; and compounding the protective layer on the surface of the pressure-sensitive adhesive layer on a hot-pressing compounding machine, eliminating internal stress through natural aging treatment, and slitting and rolling to obtain the optical functional film. The preparation process is simple and convenient, and the prepared optical film has the optical properties of high optical transmittance, high surface hardness and good weather resistance, and is high in preparation efficiency, low in cost, environment-friendly and pollution-free.

Description

Technical Field

[0001] The present invention relates to the technical field of optical films, and in particular to an optical functional film and a preparation process thereof. Background Art

[0002] Optical functional films are optical components that utilize thin layers of dielectric materials to achieve specific functions by precisely controlling the optical properties of light, such as transmission, reflection, polarization, and phase. These thin films, composed of layered dielectrics, are physically or chemically plated or coated onto a substrate surface, altering the transmission characteristics of light waves through the interference effect of light. With the continuous advancement of display technology, optical films are increasingly used in electronic display devices. As a key material connecting display panels with other optical components, their performance directly impacts the display quality and reliability of display devices. Optical films rely on the optical interference between thin film layers to finely adjust the transmittance, reflectivity, and polarization state of light in different wavelengths.

[0003] Existing optical functional films have certain deficiencies in terms of optical transmittance, surface hardness, and weather resistance. The optical transmittance of optical films is low, resulting in insufficient brightness, color distortion, and reduced clarity of the display screen; insufficient surface hardness easily causes scratches, affecting the display effect, product appearance, and performance; and poor weather resistance. Under the influence of environmental factors such as high temperature, high humidity, or ultraviolet rays, the laminated film is prone to aging and yellowing, which significantly shortens the product life. The above problems make it difficult to meet the strict requirements of high-end display equipment for optical performance and durability. At the same time, the existing preparation processes have problems such as low production efficiency, high cost, and environmental pollution. The raw materials used in some preparation processes are not environmentally friendly. A large amount of petrochemical-based materials not only consume non-renewable resources, increasing resource consumption and production costs, but also generate a large amount of volatile organic compounds during the production process, polluting the environment, not in line with the concept of sustainable development, and not conducive to large-scale industrial production. Based on this, it is particularly necessary to develop an optical functional film and its preparation process. Summary of the Invention

[0004] In view of the shortcomings of the existing technology, the purpose of the present invention is to provide an optical functional film and its preparation process, simplify the production process, and the optical film produced has excellent optical properties, high optical transmittance, high surface hardness, good weather resistance, high preparation efficiency, low cost, environmental protection and pollution-free, and is easy to promote and use.

[0005] In order to achieve the above-mentioned purpose, the present invention is realized through the following technical scheme: an optical functional film, comprising a protective layer, an optical functional layer, a pressure-sensitive adhesive layer and a release layer, wherein the protective layer, the optical functional layer, the pressure-sensitive adhesive layer and the release layer are arranged in sequence from top to bottom, and the protective layer is a recyclable polyester film layer with a hardened surface; the optical functional layer is composed of the following components in mass percentage: 30-50% bio-based polyurethane acrylate, 10-20% nano-silica, 3-8% photoinitiator, 1-3% dispersant, 0.5-2% leveling agent, 5-10% degradable plasticizer, and the balance is an environmentally friendly organic solvent; the pressure-sensitive adhesive layer is composed of an acrylic pressure-sensitive adhesive, to which a light stabilizer and an antioxidant are added; the release layer is a polyester film with a release-treated surface.

[0006] Preferably, the hardness of the protective layer reaches above 3H and the thickness is 40-60 μm.

[0007] Preferably, the particle size of the nano-silica in the optical functional layer is 10-30 nm, and the nano-silica undergoes double-layer surface modification, firstly, the surface is initially treated with a silane coupling agent, and then a secondary treatment is performed by adding a fluorinated surfactant; the photoinitiator is a mixture of 2-hydroxy-2-methyl-1-phenylacetone and benzoin dimethyl ether in a mass ratio of 1:1; the degradable plasticizer is a citrate plasticizer; the environmentally friendly organic solvent is a mixed solvent of ethanol obtained by fermenting corn starch and propylene glycol methyl ether acetate in a volume ratio of 3:2; the thickness of the optical functional layer is 30-70 μm.

[0008] Preferably, the acrylic pressure-sensitive adhesive in the pressure-sensitive adhesive layer is added with 0.5-2 wt% of a hindered amine light stabilizer and 0.3-1.5 wt% of a thioester antioxidant, and the thickness of the pressure-sensitive adhesive layer is 5-15 μm.

[0009] Preferably, the surface tension of the release layer is 20-32 mN / m, and the thickness is 20-30 μm.

[0010] A process for preparing an optical functional film comprises the following steps: (1) adding bio-based polyurethane acrylate and a degradable plasticizer to an environmentally friendly organic solvent and stirring the mixture uniformly, then sequentially adding nano-silica, a photoinitiator, a dispersant, and a leveling agent, and continuing stirring until a uniform optical functional layer solution is formed;

[0011] (2) Laying a polyester film with a release-treated surface as a release layer on a coating machine, and evenly coating the prepared optical functional layer solution on the release layer using the coating machine;

[0012] (3) sending the release layer coated with the optical functional layer solution into a curing device for curing;

[0013] (4) coating a pressure-sensitive adhesive layer on the surface of the cured optical functional layer using a coating machine;

[0014] (5) Using a surface-hardened recyclable polyester film as a protective layer, laminating it on the surface of the pressure-sensitive adhesive layer through a hot pressing roller on a hot pressing laminating machine;

[0015] (6) After the composite optical functional bonding film is subjected to natural aging treatment to eliminate internal stress, it is cut into pieces according to the required size and then rolled up to obtain the optical functional film.

[0016] Preferably, in step (1), the stirring temperature for adding the bio-based polyurethane acrylate and the degradable plasticizer to the environmentally friendly organic solvent is 45-55°C, and the stirring time is 1-2 hours; and the stirring temperature for adding the nano-silica, photoinitiator, dispersant, and leveling agent again is controlled at 55-65°C, and the stirring time is 2-3 hours.

[0017] Preferably, in step (2), the optical functional layer is coated on the release layer by a coating machine using a comma blade coating method at a coating speed of 10-15 m / min; and in step (4), the pressure-sensitive adhesive layer is coated at a speed of 5-8 m / min.

[0018] Preferably, the curing device in step (3) uses ultraviolet light for curing, and the intensity of ultraviolet light is 150-250mW / cm 2 , the irradiation time is 2-4 minutes.

[0019] Preferably, the hot pressing temperature of the protective layer hot pressing compounding in step (5) is 60-80° C., the pressure is 0.15-0.25 MPa, and the compounding time is 3-4 minutes.

[0020] Preferably, in step (6), the composite optical functional bonding film is subjected to aging treatment at a constant temperature of 45-60° C. for 2-4 hours to eliminate internal stress.

[0021] The beneficial effects of the present invention are as follows: the optical film preparation process adopts environmentally friendly materials, effectively simplifies the production process, greatly improves production efficiency, and reduces costs. At the same time, the optical functional bonding film prepared has excellent properties such as high optical transmittance, high surface hardness and good weather resistance, and has broad application prospects. DETAILED DESCRIPTION

[0022] In order to make the technical means, creative features, objectives and effects achieved by the present invention easier to understand, the present invention is further described below in conjunction with specific implementation methods.

[0023] This specific embodiment adopts the following technical scheme: an optical functional film, including a protective layer, an optical functional layer, a pressure-sensitive adhesive layer and a release layer, wherein the protective layer, the optical functional layer, the pressure-sensitive adhesive layer and the release layer are arranged in sequence from top to bottom, and the protective layer is a recyclable polyester film layer with a hardened surface; the optical functional layer is composed of the following components in percentage by mass: 30-50% bio-based polyurethane acrylate, 10-20% nano-silica, 3-8% photoinitiator, 1-3% dispersant, 0.5-2% leveling agent, 5-10% degradable plasticizer, and the balance is an environmentally friendly organic solvent; the pressure-sensitive adhesive layer is composed of an acrylate pressure-sensitive adhesive; and the release layer is a polyester film with a release-treated surface.

[0024] It is worth noting that the hardness of the protective layer reaches above 3H and the thickness is 40-60μm; the thickness of the optical functional layer is 30-70μm; the surface tension of the release layer is 20-32mN / m and the thickness is 20-30μm; the thickness of the pressure-sensitive adhesive layer is 5-15μm.

[0025] It is worth noting that the acrylic pressure-sensitive adhesive contains 0.5-2wt% hindered amine light stabilizer and 0.3-1.5wt% thioester antioxidant. The hindered amine light stabilizer can effectively capture free radicals and inhibit photooxidation reactions, and the thioester antioxidant can decompose peroxides. The two work synergistically to significantly improve the weather resistance of the bonding film.

[0026] In addition, the release layer is made of PET polyester film, and a layer of silicon dioxide-aluminum oxide composite hard coating can be deposited on the surface through plasma enhanced chemical vapor deposition technology, which has high surface hardness and improves scratch resistance and wear resistance.

[0027] The optical functional layer of this specific embodiment uses bio-based polyurethane acrylate as the main resin, containing a large amount of natural renewable raw materials, which improves environmental protection while ensuring performance. The nano-silica particle size is 10-30nm, and the nano-silica undergoes a double-layer surface modification. The surface is first treated with a silane coupling agent to enhance its compatibility with the resin matrix, and then a secondary treatment is performed by adding a fluorinated surfactant to reduce light scattering, thereby effectively improving optical transmittance. The photoinitiator is a mixture of 2-hydroxy-2-methyl-1-phenylpropanone and benzoin dimethyl ether in a mass ratio of 1:1; the biodegradable plasticizer is a citrate plasticizer; and the environmentally friendly organic solvent is a mixed solvent composed of ethanol produced by fermenting corn starch and propylene glycol methyl ether acetate in a volume ratio of 3:2.

[0028] A process for preparing an optical functional film comprises the following steps: (1) adding bio-based polyurethane acrylate and a degradable plasticizer to an environmentally friendly organic solvent and stirring the mixture to dissolve the resin and the plasticizer; then sequentially adding nano-silica, a photoinitiator, a dispersant, and a leveling agent, and continuing stirring to ensure that the nano-silica is evenly dispersed in the resin matrix until a uniform and stable optical functional layer solution is formed;

[0029] (2) Laying a polyester film with a release-treated surface as a release layer on a coating machine, and evenly coating the prepared optical functional layer solution on the release layer using the coating machine;

[0030] (3) feeding the release layer coated with the optical functional layer solution into a curing device for curing, so that the bio-based polyurethane acrylate is rapidly cured under the action of a photoinitiator to form an optical functional layer with excellent optical properties;

[0031] (4) coating a pressure-sensitive adhesive layer on the surface of the cured optical functional layer using a coating machine;

[0032] (5) Using a surface-hardened recyclable polyester film as a protective layer, laminating it on the surface of the pressure-sensitive adhesive layer through a hot pressing roller on a hot pressing laminating machine, so that the protective layer and the pressure-sensitive adhesive layer are tightly combined;

[0033] (6) After the composite optical functional bonding film is subjected to natural aging treatment to eliminate internal stress, it is cut into pieces according to the required size and then rolled up to obtain the optical functional film.

[0034] It is worth noting that in the step (1), the stirring temperature for adding the bio-based polyurethane acrylate and the degradable plasticizer to the environmentally friendly organic solvent is 45-55°C, and the stirring time is 1-2 hours; the stirring temperature for adding nano-silica, photoinitiator, dispersant, and leveling agent again is controlled at 55-65°C, and the stirring time is 2-3 hours.

[0035] In step (2), the optical functional layer is coated on the release layer by a coating machine using a comma blade coating method, and the optical functional layer solution is coated on the release layer at a coating speed of 10-15 m / min. The thickness of the optical functional layer is controlled by precisely adjusting the gap between the blade and the release layer; in step (4), the coating speed of the pressure-sensitive adhesive layer is 5-8 m / min.

[0036] Step (3) The curing device uses ultraviolet light to cure, and the ultraviolet light intensity is 150-250mW / cm 2 , the irradiation time is 2-4 minutes.

[0037] In step (5), the hot pressing temperature of the protective layer hot pressing compounding is 60-80° C., the pressure is 0.15-0.25 MPa, and the compounding time is 3-4 minutes.

[0038] Step (6) subjecting the composite optical functional bonding film to an aging treatment at a constant temperature of 45-60° C. for 2-4 hours to eliminate internal stress.

[0039] This specific embodiment solves the problems of insufficient optical performance and imperfect preparation process of existing optical functional films, and has the characteristics of high production efficiency, low cost, and environmental friendliness. It has the advantages of high optical transmittance, high surface hardness, and good weather resistance. Specifically, its technical advantages are as follows:

[0040] ① Excellent optical properties: By performing double-layer surface modification on nano-silica and adding nano-silica with a specific particle size and surface treatment to the optical functional layer, the optical transmittance can be effectively improved, making the display clearer and brighter; at the same time, the bio-based polyurethane acrylate in the optical functional layer is cured under the action of the photoinitiator to form a film layer with excellent optical properties.

[0041] ②Good mechanical properties: The protective layer has been hardened to enhance the scratch and wear resistance of the optical film, avoid scratches during use, and improve product quality and service life.

[0042] ③Outstanding weather resistance: The light stabilizer and antioxidant added to the pressure-sensitive adhesive layer work synergistically to effectively inhibit photooxidation and thermal oxidation reactions, improve the weather resistance and environmental adaptability of the laminated film, and extend its service life.

[0043] ④ Significant environmental performance: Environmentally friendly materials such as bio-based polyurethane acrylate, degradable plasticizers, environmentally friendly organic solvents and recyclable polyester films are introduced into the preparation process to reduce pollution to the environment from the source, reduce resource waste, and reduce production costs, which is in line with the concept of circular economy and sustainable development.

[0044] In summary, this preparation process is advanced, and can achieve significant improvements in the optical transmittance, surface hardness, weather resistance and environmental protection of optical functional films, meeting the urgent demand of the high-end display market for high-performance, green and environmentally friendly optical film materials. It has high production efficiency and can achieve large-scale continuous production, and has broad market application prospects.

[0045] Example 1: An optical functional film, which is provided with a protective layer, an optical functional layer, a pressure-sensitive adhesive layer and a release layer from top to bottom, wherein the protective layer is a recyclable polyester film layer with a hardened surface and a thickness of 50 μm; the optical functional layer is composed of 40% bio-based polyurethane acrylate, 15% nano-silica, 6% photoinitiator, 2% dispersant, 1.3% leveling agent, 7% degradable plasticizer, and 28.7% environmentally friendly organic solvent, and has a thickness of 50 μm; the pressure-sensitive adhesive layer is composed of an acrylic ester pressure-sensitive adhesive, to which 1.2 wt% hindered amine light stabilizer and 0.9 wt% thioester antioxidant are added, and the pressure-sensitive adhesive layer has a thickness of 10 μm; the release layer is a polyester film with a release-treated surface and a thickness of 25 μm.

[0046] The preparation process of the optical functional film is as follows: (1) adding bio-based polyurethane acrylate and degradable plasticizer to an environmentally friendly organic solvent and stirring them evenly at a stirring temperature of 50°C and a stirring time of 1.5 hours to fully dissolve the resin and plasticizer; then adding nano-silica, a photoinitiator, a dispersant, and a leveling agent in sequence, and continuing to stir, controlling the stirring temperature at 60°C and a stirring time of 2.5 hours to ensure that the nano-silica is evenly dispersed in the resin matrix until a uniform and stable optical functional layer solution is formed;

[0047] (2) Spreading a polyester film with a release-treated surface as a release layer on a coating machine, and using a comma blade coating method on the coating machine to evenly coat the prepared optical functional layer solution on the release layer at a coating speed of 13 m / min;

[0048] (3) The release layer coated with the optical functional layer solution is sent to the curing device and cured by ultraviolet light irradiation. The ultraviolet light intensity is 200mW / cm 2 , the irradiation time is 3 minutes, so that the bio-based polyurethane acrylate is quickly cured under the action of the photoinitiator;

[0049] (4) coating a pressure-sensitive adhesive layer on the surface of the cured optical functional layer using a coating machine at a coating speed of 7 m / min;

[0050] (5) Using a surface-hardened recyclable polyester film as a protective layer, the film was laminated on the surface of the pressure-sensitive adhesive layer using a hot pressing roller on a hot pressing laminating machine at a hot pressing temperature of 70°C, a pressure of 0.2 MPa, and a laminating time of 3.5 minutes, so that the protective layer and the pressure-sensitive adhesive layer were tightly bonded;

[0051] (6) The composite optical functional bonding film is subjected to natural aging treatment at a constant temperature of 57° C. for 3 hours to eliminate internal stress, and then cut into pieces according to the required size and then rolled up to obtain the optical functional film.

[0052] Example 2: An optical functional film, which is provided with a protective layer, an optical functional layer, a pressure-sensitive adhesive layer and a release layer from top to bottom, wherein the protective layer is a recyclable polyester film layer with a hardened surface and a thickness of 60 μm; the optical functional layer is composed of 30% bio-based polyurethane acrylate, 20% nano-silica, 3% photoinitiator, 3% dispersant, 0.5% leveling agent, 10% degradable plasticizer, and 33.5% environmentally friendly organic solvent, and has a thickness of 40 μm; the pressure-sensitive adhesive layer is composed of an acrylic ester pressure-sensitive adhesive, to which 2 wt% of a hindered amine light stabilizer and 0.5 wt% of a thioester antioxidant are added, and the pressure-sensitive adhesive layer has a thickness of 14 μm; the release layer is a polyester film with a release-treated surface and a thickness of 22 μm.

[0053] The preparation process of the optical functional film is as follows: (1) adding bio-based polyurethane acrylate and degradable plasticizer to an environmentally friendly organic solvent and stirring them evenly at a stirring temperature of 55°C for 1 hour to fully dissolve the resin and plasticizer; then adding nano-silica, a photoinitiator, a dispersant, and a leveling agent in sequence, and continuing to stir at a stirring temperature of 65°C for 2 hours to ensure that the nano-silica is evenly dispersed in the resin matrix until a uniform and stable optical functional layer solution is formed;

[0054] (2) Laying a polyester film with a release-treated surface as a release layer on a coating machine, and using a comma blade coating method on the coating machine, evenly coating the prepared optical functional layer solution on the release layer at a coating speed of 15 m / min;

[0055] (3) The release layer coated with the optical functional layer solution is sent to the curing device and cured by ultraviolet light irradiation. The ultraviolet light intensity is 180mW / cm 2 , the irradiation time is 4 minutes, so that the bio-based polyurethane acrylate is quickly cured under the action of the photoinitiator;

[0056] (4) coating a pressure-sensitive adhesive layer on the surface of the cured optical functional layer using a coating machine at a coating speed of 5 m / min;

[0057] (5) Using a surface-hardened recyclable polyester film as a protective layer, the film was laminated on the surface of the pressure-sensitive adhesive layer using a hot pressing roller on a hot pressing laminating machine. The hot pressing temperature was 80°C, the pressure was 0.15 MPa, and the laminating time was 4 minutes, so that the protective layer and the pressure-sensitive adhesive layer were tightly bonded.

[0058] (6) The composite optical functional bonding film is subjected to natural aging treatment at a constant temperature of 45° C. for 4 hours to eliminate internal stress, and then cut into pieces according to the required size and then rolled up to obtain the optical functional film.

[0059] Example 3: An optical functional film, which is provided with a protective layer, an optical functional layer, a pressure-sensitive adhesive layer and a release layer from top to bottom, wherein the protective layer is a recyclable polyester film layer with a hardened surface and a thickness of 40 μm; the optical functional layer is composed of 50% bio-based polyurethane acrylate, 10% nano-silica, 8% photoinitiator, 1% dispersant, 2% leveling agent, 5% degradable plasticizer, and 24% environmentally friendly organic solvent, with a thickness of 60 μm; the pressure-sensitive adhesive layer is composed of an acrylic ester pressure-sensitive adhesive, to which 1 wt% of a hindered amine light stabilizer and 1.5 wt% of a thioester antioxidant are added, and the pressure-sensitive adhesive layer has a thickness of 6 μm; the release layer is a polyester film with a release-treated surface and a thickness of 28 μm.

[0060] The preparation process of the optical functional film is as follows: (1) adding bio-based polyurethane acrylate and degradable plasticizer to an environmentally friendly organic solvent and stirring evenly at a stirring temperature of 45°C for 2 hours to fully dissolve the resin and plasticizer; then adding nano-silica, a photoinitiator, a dispersant, and a leveling agent in sequence, and continuing to stir at a stirring temperature of 55°C for 3 hours to ensure that the nano-silica is evenly dispersed in the resin matrix until a uniform and stable optical functional layer solution is formed;

[0061] (2) Laying a polyester film with a release-treated surface as a release layer on a coating machine, and using a comma blade coating method, evenly coating the prepared optical functional layer solution on the release layer at a coating speed of 11 m / min;

[0062] (3) The release layer coated with the optical functional layer solution is sent to the curing device and cured by ultraviolet light irradiation. The ultraviolet light intensity is 250mW / cm 2 , the irradiation time is 2 minutes, so that the bio-based polyurethane acrylate is quickly cured under the action of the photoinitiator;

[0063] (4) coating a pressure-sensitive adhesive layer on the surface of the cured optical functional layer using a coating machine at a coating speed of 8 m / min;

[0064] (5) Using a surface-hardened recyclable polyester film as a protective layer, the film was laminated on the surface of the pressure-sensitive adhesive layer using a hot pressing roller on a hot pressing laminating machine. The hot pressing temperature was 60°C, the pressure was 0.25 MPa, and the laminating time was 3 minutes, so that the protective layer and the pressure-sensitive adhesive layer were tightly bonded.

[0065] (6) The composite optical functional bonding film is subjected to natural aging treatment at a constant temperature of 60° C. for 2 hours to eliminate internal stress, and then cut into pieces according to the required size and then rolled up to obtain the optical functional film.

[0066] The basic principles, main features, and advantages of the present invention are shown and described above. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions are merely illustrative of the principles of the present invention. Various changes and modifications may be made to the present invention without departing from the spirit and scope of the present invention. Such changes and modifications are intended to fall within the scope of the present invention. The scope of protection claimed in the present invention is defined by the appended claims and their equivalents.

Claims

1. An optical functional film, characterized in that: The invention comprises a protective layer, an optical functional layer, a pressure-sensitive adhesive layer and a release layer, which are arranged in sequence from top to bottom. The protective layer is a recyclable polyester film layer with a hardened surface. The optical functional layer is composed of the following components in percentage by mass: 30-50% bio-based polyurethane acrylate, 10-20% nano-silicon dioxide, 3-8% photoinitiator, 1-3% dispersant, 0.5-2% leveling agent, 5-10% degradable plasticizer, and the balance is an environmentally friendly organic solvent. The pressure-sensitive adhesive layer is composed of an acrylic pressure-sensitive adhesive to which a light stabilizer and an antioxidant are added. The release layer is a polyester film with a release-treated surface.

2. The optical functional film according to claim 1, characterized in that: The hardness of the protective layer reaches above 3H, and the thickness is 40-60 μm; the surface tension of the release layer is 20-32 mN / m, and the thickness is 20-30 μm.

3. The optical functional film according to claim 1, characterized in that: The nano-silica in the optical functional layer has a particle size of 10-30 nm, and the nano-silica undergoes double-layer surface modification: first, the surface is treated primarily with a silane coupling agent, and then a secondary treatment is performed by adding a fluorinated surfactant; the photoinitiator is a mixture of 2-hydroxy-2-methyl-1-phenylacetone and benzoin dimethyl ether in a mass ratio of 1:1; the degradable plasticizer is a citrate plasticizer; the environmentally friendly organic solvent is a mixed solvent of ethanol obtained by fermenting corn starch and propylene glycol methyl ether acetate in a volume ratio of 3:2; the thickness of the optical functional layer is 30-70 μm.

4. The optical functional film according to claim 1, characterized in that: The acrylic pressure-sensitive adhesive in the pressure-sensitive adhesive layer is added with 0.5-2 wt% of a hindered amine light stabilizer and 0.3-1.5 wt% of a thioester antioxidant. The thickness of the pressure-sensitive adhesive layer is 5-15 μm.

5. A process for preparing an optical functional film, characterized in that: The steps are as follows: (1) adding bio-based polyurethane acrylate and a degradable plasticizer into an environmentally friendly organic solvent and stirring evenly, then sequentially adding nano-silica, a photoinitiator, a dispersant, and a leveling agent, and continuing to stir until a uniform optical functional layer solution is formed; (2) Laying a polyester film with a release-treated surface as a release layer on a coating machine, and evenly coating the prepared optical functional layer solution on the release layer using the coating machine; (3) sending the release layer coated with the optical functional layer solution into a curing device for curing; (4) coating a pressure-sensitive adhesive layer on the surface of the cured optical functional layer using a coating machine; (5) Using a surface-hardened recyclable polyester film as a protective layer, laminating it on the surface of the pressure-sensitive adhesive layer through a hot pressing roller on a hot pressing laminating machine; (6) After the composite optical functional bonding film is subjected to natural aging treatment to eliminate internal stress, it is cut into pieces according to the required size and then rolled up to obtain the optical functional film.

6. The process for preparing an optical functional film according to claim 5, characterized in that: In the step (1), the bio-based polyurethane acrylate and the degradable plasticizer are added to the environmentally friendly organic solvent at a stirring temperature of 45-55°C and a stirring time of 1-2 hours; and the nano-silica, photoinitiator, dispersant and leveling agent are added again at a stirring temperature of 55-65°C and a stirring time of 2-3 hours.

7. The process for preparing an optical functional film according to claim 5, characterized in that: In the step (2), the optical functional layer is coated on the release layer by a coating machine using a comma blade coating method, and the optical functional layer solution is coated on the release layer at a coating speed of 10-15 m / min; and in the step (4), the pressure-sensitive adhesive layer is coated at a coating speed of 5-8 m / min.

8. The process for preparing an optical functional film according to claim 5, characterized in that: The curing device in step (3) is cured by ultraviolet light irradiation, and the intensity of ultraviolet light is 150-250mW / cm 2 , the irradiation time is 2-4 minutes.

9. The process for preparing an optical functional film according to claim 5, wherein: The hot pressing temperature of the protective layer hot pressing compounding in step (5) is 60-80° C., the pressure is 0.15-0.25 MPa, and the compounding time is 3-4 minutes.

10. The process for preparing an optical functional film according to claim 5, characterized in that: In the step (6), the composite optical functional bonding film is subjected to aging treatment in a constant temperature environment of 45-60° C. for 2-4 hours to eliminate internal stress.