Packaged micro-prism reflective film and method of making same

Abstract

The application discloses a packaging type micro-prism reflective film and a preparation method thereof. The reflective film comprises, from top to bottom, a protective layer, a micro-prism layer, a packaging layer, a tackiness promoting layer, a supporting layer, a pressure-sensitive adhesive layer and a release layer. The tackiness promoting layer comprises the following raw materials: polyester type polyurethane acrylate, rosin modified resin, isooctyl acrylate, 1,6-hexanediol diacrylate, ethoxy nonyl phenol acrylate, a photoinitiator, fumed silica, a solvent and an organic silicon leveling agent. The reflective film adopts a seven-layer composite structure from the protective layer to the release layer. The functions of the layers are clear and the layers are cooperatively matched. The layers are firmly integrated through multiple mechanisms such as physical anchoring, chemical bonding and hot-pressing embedding. The comprehensive performance of the reflective film is excellent, and the reflective film can meet the strict requirements of high-end application fields such as traffic safety and vehicle identification on the long-term service reliability of the reflective film.

Description

Technical Field

[0001] This invention belongs to the field of reflective film preparation, specifically relating to an encapsulated microprism reflective film and its preparation method. Background Technology

[0002] Reflective film, as a functional optical thin film material, is widely used in traffic signs, vehicle license plates, safety protection facilities, and personal protective equipment. Its core principle is to use a specific optical structure to reflect incident light back to the light source along its original path, thereby achieving a high-brightness warning and identification effect at night or in low-light environments.

[0003] Currently, reflective films on the market are mainly divided into two categories: glass microsphere type and microprism type. Glass microsphere type reflective films use high-refractive-index glass microspheres as retroreflective units, utilizing the focusing and reflection of light by the microspheres to achieve retroreflection. Their advantages include relatively simple manufacturing processes and low cost. However, glass microsphere type reflective films have inherent drawbacks such as relatively limited retroreflection efficiency and poor performance at wide angles. Microprism type reflective films, on the other hand, use a cubic pyramidal microprism array as retroreflective units, utilizing the total internal reflection effect of three orthogonal reflective surfaces to achieve highly efficient retroreflection. With their higher reflectivity and superior wide-angle performance, they are gradually replacing traditional glass microsphere type reflective films and becoming the mainstream choice for high-end applications such as traffic safety and vehicle marking.

[0004] Existing microprism reflective films typically consist of a protective layer, a microprism layer, an encapsulation layer, a support layer, an adhesive backing layer, and a release layer. In this structure, there is a problem of insufficient bonding strength between the support layer and the encapsulation layer, which can easily lead to interlayer peeling, bubbling, or deformation of the microprism structure, resulting in optical performance failure; further improvement is urgently needed. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art and provide an encapsulated microprism light-emitting film and its preparation method.

[0006] The present invention adopts the following technical solution: An encapsulated microprism reflective film includes, from top to bottom, a protective layer, a microprism layer, an encapsulation layer, an adhesion-promoting layer, a support layer, a pressure-sensitive adhesive layer, and a release layer, wherein the support layer is a PET film with a thickness of 75-125 μm. The tack-enhancing layer comprises the following raw materials in parts by weight: 50-60 parts of polyester polyurethane acrylate, 8-12 parts of rosin-modified resin, 15-25 parts of isooctyl acrylate, 6-10 parts of 1,6-hexanediol diacrylate, 4-8 parts of ethoxynonylphenol acrylate, 1-3 parts of photoinitiator, 1-3 parts of fumed silica, 20-30 parts of solvent, and 1-2 parts of silicone leveling agent.

[0007] Furthermore, the adhesion-promoting layer is formed by curing an adhesion-promoting coating liquid, and the preparation method of the adhesion-promoting coating liquid is as follows: S1. Add rosin-modified resin and isooctyl acrylate to a stirred tank, heat to 40-60℃, and stir at 300-500 r / min for 20-30 min to completely dissolve the rosin-modified resin. Then cool to room temperature. S2. Add polyester polyurethane acrylate to the cooled solution of S1, and stir at 300-500 r / min for 15-20 min at room temperature to ensure that the resin and solution are fully mixed. S3. Under light-proof or yellow light conditions, continue to add photoinitiator and continue stirring at a speed of 300-500 r / min for 10-15 min to ensure that the photoinitiator is completely dissolved and uniformly dispersed. S4, then add 1,6-hexanediol diacrylate and ethoxynonylphenol acrylate, mix and stir until homogeneous, then add solvent and stir until homogeneous. S5, continue adding fumed silica, while increasing the stirring speed to 800-1200 r / min. After stirring for 20 min, reduce the stirring speed to 300-500 r / min, then add the silicone leveling agent and continue stirring for 5-10 min until homogeneous. S6. Degas the mixture obtained in S4 under a vacuum of -0.08 to -0.1 MPa for 10-15 minutes, let it stand to defoam, and then filter to obtain the adhesion-promoting coating liquid.

[0008] Furthermore, the solid content of the adhesion-promoting coating liquid is 40-60%, and the viscosity is 100-500 mPa·s.

[0009] Furthermore, the photoinitiator is composed of photoinitiator 1173 and photoinitiator TPO in a mass ratio of 3:2.

[0010] Furthermore, the solvent is ethyl acetate or butanone.

[0011] Furthermore, the encapsulation layer comprises the following raw materials in parts by weight: 45-55 parts aliphatic polyurethane acrylate, 8-12 parts polyether polyurethane acrylate, 10-20 parts trifluoroethyl methacrylate, 8-15 parts ethoxyethoxyethyl acrylate, 3-8 parts tricyclodecanediethanol diacrylate, 1-2 parts 1-hydroxycyclohexylphenyl ketone, 0.5-1.5 parts phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide, 1-3 parts phosphate-modified acrylate, 1-3 parts polyamide wax, 0.3-0.8 parts antioxidant, and 15-25 parts ethyl acetate.

[0012] Furthermore, the encapsulation layer is formed by curing an encapsulation layer coating liquid, and the preparation method of the encapsulation layer coating liquid is as follows: A. At room temperature, aliphatic polyurethane acrylate, polyether polyurethane acrylate, trifluoroethyl methacrylate, ethoxyethoxyethyl acrylate and tricyclodecanediethanol diacrylate are added sequentially to a stirred tank and stirred at 300-500 r / min for 15-20 min to ensure that the components are mixed evenly to obtain a resin premix. B. Under light-protected or yellow light conditions, add 1-hydroxycyclohexylphenyl ketone and phenyl bis(2,4,6-trimethylbenzoyl)phosphine oxide to the resin premix, and continue stirring at 300-500 r / min for 15-20 min to ensure that the components are mixed evenly to obtain the premix. C. Continue adding phosphate-modified acrylate and antioxidant to the premix, and continue stirring for 10-15 minutes until homogeneous to obtain the mixture; D. Add a portion of ethyl acetate to the mixture obtained in step C, stir until homogeneous, add polyamide wax, increase the stirring speed to 800-1200 r / min, heat to 40-50℃, continue stirring for 20-30 min, then add the remaining ethyl acetate, reduce the stirring speed to 300-500 r / min, continue stirring for 10-15 min, and cool to room temperature. E. Degas the mixture obtained in step D under a vacuum of -0.08 to -0.1 MPa for 10-15 minutes, and then filter to obtain the encapsulation layer coating liquid.

[0013] Furthermore, the solid content of the coating liquid for the encapsulation layer is 50-60%, and the viscosity is 200-400 mPa·s.

[0014] A fabrication process for an encapsulated microprism reflective film includes the following steps: Step 1: Corona treatment is performed on the substrate. The UV resin of the microprism layer is coated on the surface of the substrate. Then, the mold belt with the microprism structure is aligned with the substrate and fed into the elastic mirror steel roller. The temperature of the steel roller is controlled at 65°C and the pressure is 6MPa. The UV resin is pressed into the microprism structure of the mold belt. Then, it is cured under nitrogen protection. After complete curing, the mold belt is peeled off to form the microprism layer. Step 2: Apply the protective layer slurry to the other side of the substrate and cure to form a protective layer; Step 3: Perform corona treatment on the side of the support layer and the encapsulation layer that are opposite to each other, then apply an adhesion-promoting coating liquid to its surface, dry it at 80-100℃ for 1-3 minutes, and then cure it under nitrogen protection with ultraviolet light to form an adhesion-promoting layer with a thickness of 2-5 μm. Step 4: Apply the encapsulation layer coating liquid to the surface of the adhesion-promoting layer described in step 3, then dry it at 80-100°C for 1-3 minutes, and then cure it under ultraviolet light under nitrogen protection to form the encapsulation layer. Step 5: The materials obtained in Step 2 and Step 4 are passed through a pressure roller, which causes the microprism layer with the prism structure facing down and the encapsulation layer to be hot-pressed and bonded together at high temperature. The temperature of the pressure roller is 160-180℃ and the pressure is 0.1-0.3MPa. Step 6: Perform corona treatment on the other side of the support layer, then take a pressure-sensitive adhesive layer with a release layer, and composite the pressure-sensitive adhesive layer with the support layer. After composite, roll it up and let it stand for 24 hours to obtain the encapsulated microprism reflective film.

[0015] Furthermore, in step 1, during UV resin curing, the UV curing energy is controlled at 1200 mJ / cm². 2 In step 3, during the curing of the tack-promoting coating liquid, the UV curing energy is controlled at 800 mJ / cm². 2 In step 4, during the curing of the encapsulation layer coating liquid, the UV curing energy is controlled at 1000 mJ / cm². 2 .

[0016] As can be seen from the above description of the present invention, compared with the prior art, the beneficial effects of the present invention are: First, the reflective film adopts a seven-layer composite structure from the protective layer to the release layer, with each layer having a clear functional positioning and working in concert. The protective layer provides weather resistance and scratch resistance, the microprism layer achieves efficient retroreflection, the encapsulation layer provides physical support and optical interface maintenance, the adhesion-promoting layer ensures interlayer bonding, the support layer provides a mechanical skeleton and dimensional stability, and the pressure-sensitive adhesive layer and release layer facilitate terminal bonding construction. The layers form a solid overall structure through multiple mechanisms such as physical anchoring, chemical bonding, and hot-pressing embedding, resulting in excellent comprehensive performance that can meet the stringent requirements for long-term reliability of reflective film in high-end application fields such as traffic safety and vehicle marking. Secondly, the raw material composition of the tack-promoting layer is specifically defined, with polyester-type polyurethane acrylate as the main resin. The polyester segments in the polyester-type polyurethane acrylate have a similar ester group structure to the PET support layer, which can generate strong intermolecular forces. Ethoxy-nonylphenol acrylate is introduced to work with the main resin to further enhance the physical anchoring of the tack-promoting layer to the support layer. Rosin-modified resin is introduced to improve the initial tack and wettability of the tack-promoting layer to the support layer, ensuring full spreading and tight adhesion during coating. Fumed silica is introduced to construct a thixotropic network, preventing coating liquid from dripping and forming a micro-rough surface, increasing the mechanical anchoring area. The synergistic effect of the multi-layer interface significantly improves the peel strength between the encapsulation layer and the support layer, and it can still maintain excellent interlayer adhesion after long-term outdoor aging. Secondly, isooctyl acrylate is introduced into the tackifying layer as a flexible active diluent to give the tackifying layer good flexibility and low shrinkage; 1,6-hexanediol diacrylate is introduced to adjust the crosslinking density and balance the cohesive strength; silicone leveling agent is introduced to improve the smoothness of the coating film; the overall formula has a moderate viscosity, which is suitable for precision coating processes such as microgravure, and the curing speed is fast to meet the needs of continuous industrial production. Third, the raw material composition of the encapsulation layer is specifically defined. Trifluoroethyl methacrylate is introduced to reduce the refractive index of the matrix. At the same time, phosphate-modified acrylate is added to the formula as an adhesive to enhance the adhesion between the encapsulation layer and the bottom surface of the microprism layer. 1-hydroxycyclohexylphenyl ketone is introduced in combination with phenyl bis(2,4,6-trimethylbenzoyl)phosphine oxide to construct a dual initiation system to ensure uniform curing of the encapsulation layer in the thickness direction and avoid performance degradation caused by incomplete curing at the bottom. Fourth, this application adopts a split composite process, first preparing the microprism layer and the support layer with adhesion-promoting and encapsulation layers separately, and then high-temperature pressing and encapsulation, which avoids deformation of the microprism structure during multiple processing and ensures the stability of retroreflective performance; the core process clearly requires corona treatment to increase the surface tension of the substrate, and nitrogen-protected UV curing to avoid oxygen inhibition and ensure complete curing; moreover, the process parameters are completely compatible with the formula and can be directly connected to existing mass production lines without additional equipment modification; at the same time, the curing temperature is low, avoiding thermal shrinkage and deformation of the PET support layer, ensuring the overall flatness of the reflective film and the optical accuracy of the microprism. Detailed Implementation

[0017] The present invention will be further described below through specific embodiments.

[0018] An encapsulated microprism reflective film includes, from top to bottom, a protective layer, a microprism layer, an encapsulation layer, an adhesion-promoting layer, a support layer, a pressure-sensitive adhesive layer, and a release layer, wherein the support layer is a PET film with a thickness of 75-125 μm.

[0019] The tack-promoting layer comprises the following raw materials in parts by weight: 50-60 parts polyester-type polyurethane acrylate, 8-12 parts rosin-modified resin, 15-25 parts isooctyl acrylate, 6-10 parts 1,6-hexanediol diacrylate, 4-8 parts ethoxynonylphenol acrylate, 1-3 parts photoinitiator, 1-3 parts fumed silica, 20-30 parts solvent, and 1-2 parts silicone leveling agent; wherein the solid content of the tack-promoting layer coating liquid is 40-60%, and the viscosity is 100-500 mPa·s; the photoinitiator is composed of photoinitiator 1173 and photoinitiator TPO in a mass ratio of 3:2; the solvent is ethyl acetate or butanone. Further, the tack-promoting layer is formed by curing the tack-promoting layer coating liquid, and the preparation method of the tack-promoting layer coating liquid is as follows: S1. Add rosin-modified resin and isooctyl acrylate to a stirred tank, heat to 40-60℃, and stir at 300-500 r / min for 20-30 min to completely dissolve the rosin-modified resin. Then cool to room temperature. S2. Add polyester polyurethane acrylate to the cooled solution of S1, and stir at 300-500 r / min for 15-20 min at room temperature to ensure that the resin and solution are fully mixed. S3. Under light-proof or yellow light conditions, continue to add photoinitiator and continue stirring at a speed of 300-500 r / min for 10-15 min to ensure that the photoinitiator is completely dissolved and uniformly dispersed. S4, then add 1,6-hexanediol diacrylate and ethoxynonylphenol acrylate, mix and stir until homogeneous, then add solvent and stir until homogeneous. S5, continue adding fumed silica, while increasing the stirring speed to 800-1200 r / min. After stirring for 20 min, reduce the stirring speed to 300-500 r / min, then add the silicone leveling agent and continue stirring for 5-10 min until homogeneous. S6. Degas the mixture obtained in S4 under a vacuum of -0.08 to -0.1 MPa for 10-15 minutes. After standing and defoaming, filter to obtain the adhesion-promoting coating liquid.

[0020] The encapsulation layer comprises the following raw materials in parts by weight: 45-55 parts aliphatic polyurethane acrylate, 8-12 parts polyether polyurethane acrylate, 10-20 parts trifluoroethyl methacrylate, 8-15 parts ethoxyethoxyethyl acrylate, 3-8 parts tricyclodecanediethanol diacrylate, 1-2 parts 1-hydroxycyclohexylphenyl ketone, 0.5-1.5 parts phenyl bis(2,4,6-trimethylbenzoyl)phosphine oxide, 1-3 parts phosphate-modified acrylate, 1-3 parts polyamide wax, 0.3-0.8 parts antioxidant, and 15-25 parts ethyl acetate; wherein the solid content of the encapsulation layer coating liquid is 50-60%, and the viscosity is 200-400 mPa·s. Further, the encapsulation layer is formed by curing the encapsulation layer coating liquid, and the preparation method of the encapsulation layer coating liquid is as follows: A. At room temperature, aliphatic polyurethane acrylate, polyether polyurethane acrylate, trifluoroethyl methacrylate, ethoxyethoxyethyl acrylate and tricyclodecanediethanol diacrylate are added sequentially to a stirred tank and stirred at 300-500 r / min for 15-20 min to ensure that the components are mixed evenly to obtain a resin premix. B. Under light-protected or yellow light conditions, add 1-hydroxycyclohexylphenyl ketone and phenyl bis(2,4,6-trimethylbenzoyl)phosphine oxide to the resin premix, and continue stirring at 300-500 r / min for 15-20 min to ensure that the components are mixed evenly to obtain the premix. C. Continue adding phosphate-modified acrylate and antioxidant to the premix, and continue stirring for 10-15 minutes until homogeneous to obtain the mixture; D. Add a portion of ethyl acetate to the mixture obtained in step C, stir until homogeneous, add polyamide wax, increase the stirring speed to 800-1200 r / min, heat to 40-50℃, continue stirring for 20-30 min, then add the remaining ethyl acetate, reduce the stirring speed to 300-500 r / min, continue stirring for 10-15 min, and cool to room temperature. E. Degas the mixture obtained in step D under a vacuum of -0.08 to -0.1 MPa for 10-15 minutes, and then filter to obtain the encapsulation layer coating liquid.

[0021] A fabrication process for an encapsulated microprism reflective film includes the following steps: Step 1: The substrate is subjected to corona treatment. A microprism layer of UV resin is coated onto the substrate surface. Then, a mold belt with a microprism structure is aligned with the substrate and fed into an elastic mirror steel roller. The roller temperature is controlled at 65℃ and the pressure at 6MPa to press the UV resin into the microprism structure of the mold belt. Curing then occurs under nitrogen protection, with the UV curing energy controlled at 1200mJ / cm². 2 After complete curing, the mold strip is peeled off to form a microprism layer, wherein the substrate can be PET film; Step 2: Apply the protective layer slurry to the other side of the substrate and cure to form a protective layer; Step 3: Perform corona treatment on the side of the support layer and the encapsulation layer opposite each other, then apply an adhesion promoter coating liquid to its surface, followed by drying at 80-100℃ for 1-3 minutes, and then UV curing under nitrogen protection, controlling the UV curing energy to 800mJ / cm². 2 This forms an adhesion-promoting layer with a thickness of 2-5 μm; Step 4: Apply the encapsulation layer coating liquid to the surface of the adhesion-promoting layer described in Step 3, then dry at 80-100℃ for 1-3 minutes, followed by UV curing under nitrogen protection, controlling the UV curing energy to 1000 mJ / cm². 2 This forms an encapsulation layer; Step 5: The materials obtained in Step 2 and Step 4 are passed through a pressure roller, which causes the microprism layer with the prism structure facing down and the encapsulation layer to be hot-pressed and bonded together at high temperature. The temperature of the pressure roller is 160-180℃ and the pressure is 0.1-0.3MPa. Step 6: Perform corona treatment on the other side of the support layer, then take a pressure-sensitive adhesive layer with a release layer, and composite the pressure-sensitive adhesive layer with the support layer. After composite, roll it up and let it stand for 24 hours to obtain the encapsulated microprism reflective film.

[0022] Example 1 An encapsulated microprism reflective film includes, from top to bottom, a protective layer, a microprism layer, an encapsulation layer, an adhesion-promoting layer, a support layer, a pressure-sensitive adhesive layer, and a release layer, wherein the support layer is a PET film with a thickness of 75 μm.

[0023] The tack-promoting layer comprises the following raw materials in parts by weight: 50 parts polyester-type polyurethane acrylate, 12 parts rosin-modified resin, 15 parts isooctyl acrylate, 6 parts 1,6-hexanediol diacrylate, 8 parts ethoxynonylphenol acrylate, 1 part photoinitiator, 3 parts fumed silica, 20 parts ethyl acetate, and 2 parts silicone leveling agent; wherein the solid content of the tack-promoting layer coating liquid is 40%, and the viscosity is 100 mPa·s. Further, the tack-promoting layer is formed by curing the tack-promoting layer coating liquid, and the preparation method of the tack-promoting layer coating liquid is as follows: S1. Add rosin-modified resin and isooctyl acrylate to a stirred tank, heat to 40°C, and stir at 500 rpm for 20 minutes to completely dissolve the rosin-modified resin. Then cool to room temperature. S2. Add polyester polyurethane acrylate to the cooled solution of S1, and stir at 500 r / min for 15 min at room temperature to ensure that the resin and solution are fully mixed. S3, under light-proof or yellow light conditions, continue to add photoinitiator and continue stirring at 500 r / min for 10 min to completely dissolve and uniformly disperse the photoinitiator; S4, then add 1,6-hexanediol diacrylate and ethoxynonylphenol acrylate, mix and stir until homogeneous, then add solvent and stir until homogeneous. S5, continue adding fumed silica, while increasing the stirring speed to 1200 r / min. After stirring for 20 min, reduce the stirring speed to 500 r / min, then add the silicone leveling agent and continue stirring for 5 min until homogeneous. S6. The mixture obtained in S4 is degassed under a vacuum of -0.08MPa for 15 minutes, allowed to stand to defoam, and then filtered to obtain the adhesion-promoting coating liquid.

[0024] The encapsulation layer comprises the following raw materials in parts by weight: 45 parts aliphatic polyurethane acrylate, 12 parts polyether polyurethane acrylate, 10 parts trifluoroethyl methacrylate, 15 parts ethoxyethoxyethyl acrylate, 3 parts tricyclodecanediethanol diacrylate, 2 parts 1-hydroxycyclohexylphenyl ketone, 0.5 parts phenyl bis(2,4,6-trimethylbenzoyl)phosphine oxide, 3 parts phosphate-modified acrylate, 1 part polyamide wax, 0.8 parts antioxidant, and 15 parts ethyl acetate; wherein the solid content of the encapsulation layer coating liquid is 50%, and the viscosity is 200 mPa·s. Further, the encapsulation layer is formed by curing the encapsulation layer coating liquid, and the preparation method of the encapsulation layer coating liquid is as follows: A. At room temperature, aliphatic polyurethane acrylate, polyether polyurethane acrylate, trifluoroethyl methacrylate, ethoxyethoxyethyl acrylate and tricyclodecanediethanol diacrylate are added sequentially to a stirred tank and stirred at 300 r / min for 20 min to ensure that the components are mixed evenly to obtain a resin premix. B. Under light-protected or yellow light conditions, add 1-hydroxycyclohexylphenyl ketone and phenyl bis(2,4,6-trimethylbenzoyl)phosphine oxide to the resin premix, and continue stirring at 300 r / min for 20 min to ensure that the components are mixed evenly to obtain the premix. C. Continue to add phosphate-modified acrylate and antioxidant to the premix, and continue stirring for 15 minutes until homogeneous to obtain the mixture; D. Add a portion of ethyl acetate to the mixture obtained in step C, stir until homogeneous, add polyamide wax, increase the stirring speed to 800 r / min, heat to 40°C, continue stirring for 30 min, then add the remaining ethyl acetate, reduce the stirring speed to 300 r / min, continue stirring for 15 min, and cool to room temperature. E. Degas the mixture obtained in step D under a vacuum of -0.08 MPa for 15 minutes, and then filter it to obtain the encapsulation layer coating liquid.

[0025] A fabrication process for an encapsulated microprism reflective film includes the following steps: Step 1: The substrate is subjected to corona treatment. A microprism layer of UV resin is coated onto the substrate surface. Then, a mold belt with a microprism structure is aligned with the substrate and fed into an elastic mirror steel roller. The roller temperature is controlled at 65℃ and the pressure at 6MPa to press the UV resin into the microprism structure of the mold belt. Curing then occurs under nitrogen protection, with the UV curing energy controlled at 1200mJ / cm². 2 After complete curing, the mold strip is peeled off to form a microprism layer; Step 2: Apply the protective layer slurry to the other side of the substrate and cure to form a protective layer; Step 3: Perform corona treatment on the side of the support layer and encapsulation layer opposite each other, then apply an adhesion promoter coating liquid to its surface, followed by drying at 80°C for 3 minutes, and then UV curing under nitrogen protection, controlling the UV curing energy to be 800 mJ / cm². 2 This forms an adhesion-promoting layer with a thickness of 2 μm; Step 4: Apply the encapsulation layer coating liquid to the surface of the adhesion-promoting layer described in Step 3, then dry at 80°C for 3 minutes. Next, cure under nitrogen protection using ultraviolet light, controlling the UV curing energy to be 1000 mJ / cm². 2 This forms an encapsulation layer; Step 5: The materials obtained in Step 2 and Step 4 are passed through a pressure roller, which causes the microprism layer with the prism structure facing down and the encapsulation layer to be hot-pressed and bonded together at a high temperature. The temperature of the pressure roller is 160°C and the pressure is 0.3 MPa. Step 6: Perform corona treatment on the other side of the support layer, then take a pressure-sensitive adhesive layer with a release layer, and composite the pressure-sensitive adhesive layer with the support layer. After composite, roll it up and let it stand for 24 hours to obtain the encapsulated microprism reflective film.

[0026] Example 2 An encapsulated microprism reflective film includes, from top to bottom, a protective layer, a microprism layer, an encapsulation layer, an adhesion-promoting layer, a support layer, a pressure-sensitive adhesive layer, and a release layer, wherein the support layer is a PET film with a thickness of 125 μm.

[0027] The tack-promoting layer comprises the following raw materials in parts by weight: 60 parts polyester-type polyurethane acrylate, 8 parts rosin-modified resin, 25 parts isooctyl acrylate, 10 parts 1,6-hexanediol diacrylate, 4 parts ethoxynonylphenol acrylate, 3 parts photoinitiator, 1 part fumed silica, 30 parts methyl ethyl ketone (MEK), and 1 part silicone leveling agent; wherein the solid content of the tack-promoting layer coating liquid is 60%, and the viscosity is 500 mPa·s. Further, the tack-promoting layer is formed by curing the tack-promoting layer coating liquid, and the preparation method of the tack-promoting layer coating liquid is as follows: S1, add rosin-modified resin and isooctyl acrylate to a stirred tank, heat to 60°C, and stir at 300 r / min for 30 min to completely dissolve the rosin-modified resin, then cool to room temperature. S2. Add polyester polyurethane acrylate to the cooled solution of S1, and stir at 300 r / min for 20 min at room temperature to ensure that the resin and solution are fully mixed. S3, under light-proof or yellow light conditions, continue to add photoinitiator and continue stirring at 300 r / min for 15 min to completely dissolve and uniformly disperse the photoinitiator; S4, then add 1,6-hexanediol diacrylate and ethoxynonylphenol acrylate, mix and stir until homogeneous, then add solvent and stir until homogeneous. S5, continue adding fumed silica, while increasing the stirring speed to 800 r / min. After stirring for 20 min, reduce the stirring speed to 300 r / min, then add the silicone leveling agent and continue stirring for 10 min until homogeneous. S6. The mixture obtained in S4 is degassed under a vacuum of -0.1 MPa for 10 minutes, allowed to stand to defoam, and then filtered to obtain the adhesion-promoting coating liquid.

[0028] The encapsulation layer comprises the following raw materials in parts by weight: 55 parts aliphatic polyurethane acrylate, 8 parts polyether polyurethane acrylate, 20 parts trifluoroethyl methacrylate, 8 parts ethoxyethoxyethyl acrylate, 8 parts tricyclodecanediethanol diacrylate, 1 part 1-hydroxycyclohexylphenyl ketone, 1.5 parts phenyl bis(2,4,6-trimethylbenzoyl)phosphine oxide, 1 part phosphate-modified acrylate, 3 parts polyamide wax, 0.3 parts antioxidant, and 25 parts ethyl acetate; wherein the solid content of the encapsulation layer coating liquid is 60%, and the viscosity is 400 mPa·s. Further, the encapsulation layer is formed by curing the encapsulation layer coating liquid, and the preparation method of the encapsulation layer coating liquid is as follows: A. At room temperature, aliphatic polyurethane acrylate, polyether polyurethane acrylate, trifluoroethyl methacrylate, ethoxyethoxyethyl acrylate and tricyclodecanediethanol diacrylate are added sequentially to a stirred tank and stirred at 500 r / min for 15 min to ensure that the components are mixed evenly to obtain a resin premix. B. Under light-protected or yellow light conditions, add 1-hydroxycyclohexylphenyl ketone and phenyl bis(2,4,6-trimethylbenzoyl)phosphine oxide to the resin premix, and continue stirring at 500 r / min for 15 min to ensure that the components are mixed evenly to obtain the premix. C. Continue to add phosphate-modified acrylate and antioxidant to the premix, and continue stirring for 10 minutes until homogeneous to obtain the mixture; D. Add a portion of ethyl acetate to the mixture obtained in step C, stir until homogeneous, add polyamide wax, increase the stirring speed to 1200 r / min, heat to 50°C, continue stirring for 20 min, then add the remaining ethyl acetate, reduce the stirring speed to 500 r / min, continue stirring for 10 min, and cool to room temperature. E. Degas the mixture obtained in step D under a vacuum of -0.1 MPa for 10 minutes, and then filter to obtain the encapsulation layer coating liquid.

[0029] A fabrication process for an encapsulated microprism reflective film includes the following steps: Step 1: The substrate is subjected to corona treatment. A microprism layer of UV resin is coated onto the substrate surface. Then, a mold belt with a microprism structure is aligned with the substrate and fed into an elastic mirror steel roller. The roller temperature is controlled at 65℃ and the pressure at 6MPa to press the UV resin into the microprism structure of the mold belt. Curing then occurs under nitrogen protection, with the UV curing energy controlled at 1200mJ / cm². 2 After complete curing, the mold strip is peeled off to form a microprism layer; Step 2: Apply the protective layer slurry to the other side of the substrate and cure to form a protective layer; Step 3: Perform corona treatment on the side of the support layer and the encapsulation layer opposite each other, then apply an adhesion promoter coating liquid to its surface, followed by drying at 100°C for 1 minute, and then UV curing under nitrogen protection, controlling the UV curing energy to be 800 mJ / cm². 2 This forms an adhesion-promoting layer with a thickness of 5 μm; Step 4: Apply the encapsulation layer coating liquid to the surface of the adhesion-promoting layer described in Step 3, then dry at 100°C for 1 minute, followed by UV curing under nitrogen protection, controlling the UV curing energy to be 1000 mJ / cm². 2 This forms an encapsulation layer; Step 5: The materials obtained in Step 2 and Step 4 are passed through a pressure roller, which causes the microprism layer with the prism structure facing down and the encapsulation layer to be hot-pressed and bonded together at a high temperature. The temperature of the pressure roller is 180°C and the pressure is 0.1 MPa. Step 6: Perform corona treatment on the other side of the support layer, then take a pressure-sensitive adhesive layer with a release layer, and composite the pressure-sensitive adhesive layer with the support layer. After composite, roll it up and let it stand for 24 hours to obtain the encapsulated microprism reflective film.

[0030] Example 3 An encapsulated microprism reflective film includes, from top to bottom, a protective layer, a microprism layer, an encapsulation layer, an adhesion-promoting layer, a support layer, a pressure-sensitive adhesive layer, and a release layer, wherein the support layer is a 100µm thick PET film.

[0031] The tack-promoting layer comprises the following raw materials in parts by weight: 55 parts polyester-type polyurethane acrylate, 10 parts rosin-modified resin, 20 parts isooctyl acrylate, 8 parts 1,6-hexanediol diacrylate, 6 parts ethoxynonylphenol acrylate, 2 parts photoinitiator, 2 parts fumed silica, 25 parts ethyl acetate, and 1.5 parts silicone leveling agent; wherein the solid content of the tack-promoting layer coating liquid is 50%, and the viscosity is 300 mPa·s. Further, the tack-promoting layer is formed by curing the tack-promoting layer coating liquid, and the preparation method of the tack-promoting layer coating liquid is as follows: S1. Add rosin-modified resin and isooctyl acrylate to a stirred tank, heat to 50°C, and stir at 400 rpm for 25 minutes to completely dissolve the rosin-modified resin. Then cool to room temperature. S2. Add polyester polyurethane acrylate to the cooled solution of S1, and stir at 400 r / min for 18 min at room temperature to ensure that the resin and solution are fully mixed. S3, under light-proof or yellow light conditions, continue to add photoinitiator and continue stirring at 400 r / min for 12 min to completely dissolve and uniformly disperse the photoinitiator; S4, then add 1,6-hexanediol diacrylate and ethoxynonylphenol acrylate, mix and stir until homogeneous, then add solvent and stir until homogeneous. S5, continue adding fumed silica, while increasing the stirring speed to 1000 r / min. After stirring for 20 min, reduce the stirring speed to 400 r / min, then add the silicone leveling agent and continue stirring for 8 min until homogeneous. S6. The mixture obtained in S4 is degassed under a vacuum of -0.09 MPa for 12 minutes, allowed to stand to defoam, and then filtered to obtain the adhesion-promoting coating liquid.

[0032] The encapsulation layer comprises the following raw materials in parts by weight: 50 parts aliphatic polyurethane acrylate, 10 parts polyether polyurethane acrylate, 15 parts trifluoroethyl methacrylate, 12 parts ethoxyethoxyethyl acrylate, 5 parts tricyclodecanediethanol diacrylate, 1.5 parts 1-hydroxycyclohexylphenyl ketone, 1.0 part phenyl bis(2,4,6-trimethylbenzoyl)phosphine oxide, 2 parts phosphate-modified acrylate, 2 parts polyamide wax, 0.5 parts antioxidant, and 20 parts ethyl acetate; wherein the solid content of the encapsulation layer coating liquid is 55%, and the viscosity is 300 mPa·s. Further, the encapsulation layer is formed by curing the encapsulation layer coating liquid, and the preparation method of the encapsulation layer coating liquid is as follows: A. At room temperature, aliphatic polyurethane acrylate, polyether polyurethane acrylate, trifluoroethyl methacrylate, ethoxyethoxyethyl acrylate and tricyclodecanediethanol diacrylate are added sequentially to a stirred tank and stirred at 400 r / min for 18 min to ensure that the components are mixed evenly to obtain a resin premix. B. Under light-protected or yellow light conditions, add 1-hydroxycyclohexylphenyl ketone and phenyl bis(2,4,6-trimethylbenzoyl)phosphine oxide to the resin premix, and continue stirring at 400 r / min for 18 min to ensure that the components are mixed evenly to obtain the premix. C. Continue to add phosphate-modified acrylate and antioxidant to the premix, and continue stirring for 12 minutes until homogeneous to obtain the mixture; D. Add a portion of ethyl acetate to the mixture obtained in step C, stir until homogeneous, add polyamide wax, increase the stirring speed to 1000 r / min, heat to 45°C, continue stirring for 25 min, then add the remaining ethyl acetate, reduce the stirring speed to 400 r / min, continue stirring for 12 min, and cool to room temperature. E. Degas the mixture obtained in step D under a vacuum of -0.09 MPa for 12 minutes, and then filter to obtain the encapsulation layer coating liquid.

[0033] A fabrication process for an encapsulated microprism reflective film includes the following steps: Step 1: The substrate is subjected to corona treatment. A microprism layer of UV resin is coated onto the substrate surface. Then, a mold belt with a microprism structure is aligned with the substrate and fed into an elastic mirror steel roller. The roller temperature is controlled at 65℃ and the pressure at 6MPa to press the UV resin into the microprism structure of the mold belt. Curing then occurs under nitrogen protection, with the UV curing energy controlled at 1200mJ / cm². 2 After complete curing, the mold strip is peeled off to form a microprism layer; Step 2: Apply the protective layer slurry to the other side of the substrate and cure to form a protective layer; Step 3: Perform corona treatment on the side of the support layer and encapsulation layer opposite each other, then apply an adhesion promoter coating liquid to its surface, dry at 90°C for 2 minutes, and then perform ultraviolet curing under nitrogen protection, controlling the UV curing energy to be 800 mJ / cm². 2 This forms an adhesion-promoting layer with a thickness of 3 μm; Step 4: Apply the encapsulation layer coating liquid to the surface of the adhesion-promoting layer described in Step 3, then dry at 90°C for 2 minutes. Next, cure under nitrogen protection using ultraviolet light, controlling the UV curing energy to be 1000 mJ / cm². 2 This forms an encapsulation layer; Step 5: The materials obtained in Step 2 and Step 4 are passed through a pressure roller, which causes the microprism layer with the prism structure facing down and the encapsulation layer to be hot-pressed and bonded together at high temperature. The temperature of the pressure roller is 170°C and the pressure is 0.2 MPa. Step 6: Perform corona treatment on the other side of the support layer, then take a pressure-sensitive adhesive layer with a release layer, and composite the pressure-sensitive adhesive layer with the support layer. After composite, roll it up and let it stand for 24 hours to obtain the encapsulated microprism reflective film.

[0034] Comparative Example 1 Its structure, raw material composition and preparation method are basically the same as those in Example 3. The main difference is that no adhesion-promoting layer is set between the encapsulation layer and the microprism layer, and the encapsulation layer is directly coated on the support layer.

[0035] Comparative Example 2 Its structure, raw material composition and preparation method are basically the same as those in Example 3. The main difference is that the tackifying layer formulation does not contain rosin-modified resin and ethoxynonylphenol acrylate, and the proportions of the two are replaced by polyester polyurethane acrylate in equal amounts.

[0036] The encapsulated microprism reflective films prepared in Examples 1-3 and Comparative Examples 1-2 were subjected to performance tests. The specific results are shown in Table 1. The peel strength test was conducted according to the test conditions of GB / T 2792 (sample width 25 mm, peel speed 300 mm / min).

[0037] Table 1 Performance Test Table

[0038] As shown in the table above, this application significantly improves the peel strength between the encapsulation layer and the support layer by setting a specific adhesive-promoting layer, with initial peel strengths all exceeding 27 N / 25 mm; after rigorous high-temperature and high-humidity aging, the peel strength retention rate still exceeds 90%. In contrast, Comparative Example 1, which did not have an adhesive-promoting layer, had low peel strength and significant degradation after aging; Comparative Example 2, which used a conventional primer without rosin-modified resin and ethoxynonylphenol acrylate, also had significantly lower peel strength and aging retention rate than this application.

[0039] In summary, the encapsulated microprism reflective film specified in this application adopts a seven-layer composite structure from the protective layer to the release layer. Each layer has a clearly defined function and works synergistically. The protective layer provides weather resistance and scratch resistance, the microprism layer achieves efficient retroreflection, the encapsulation layer provides physical support and maintains the optical interface, the adhesion-promoting layer ensures interlayer bonding, the support layer provides a mechanical skeleton and dimensional stability, and the pressure-sensitive adhesive layer and release layer facilitate terminal bonding construction. The layers form a robust overall structure through multiple mechanisms such as physical anchoring, chemical bonding, and thermo-pressing embedding. It has excellent comprehensive performance and can meet the stringent requirements for long-term reliability of reflective films in high-end application fields such as traffic safety and vehicle marking.

[0040] The above description is merely a preferred embodiment of the present invention and should not be construed as limiting the scope of the present invention. All equivalent changes and modifications made in accordance with the scope of the present invention and the contents of the specification should still fall within the scope of the present invention.

Claims

1. An encapsulated microprism reflective film, characterized in that: It includes, from top to bottom, a protective layer, a microprism layer, an encapsulation layer, an adhesion promoter layer, a support layer, a pressure-sensitive adhesive layer, and a release layer. The support layer is made of PET film with a thickness of 75-125um. The tack-enhancing layer comprises the following raw materials in parts by weight: 50-60 parts of polyester polyurethane acrylate, 8-12 parts of rosin-modified resin, 15-25 parts of isooctyl acrylate, 6-10 parts of 1,6-hexanediol diacrylate, 4-8 parts of ethoxynonylphenol acrylate, 1-3 parts of photoinitiator, 1-3 parts of fumed silica, 20-30 parts of solvent, and 1-2 parts of silicone leveling agent.

2. The encapsulated microprism reflective film according to claim 1, characterized in that: The adhesion-promoting layer is formed by curing an adhesion-promoting coating liquid, and the preparation method of the adhesion-promoting coating liquid is as follows: S1. Add rosin-modified resin and isooctyl acrylate to a stirred tank, heat to 40-60℃, and stir at 300-500 r / min for 20-30 min to completely dissolve the rosin-modified resin. Then cool to room temperature. S2. Add polyester polyurethane acrylate to the cooled solution of S1, and stir at 300-500 r / min for 15-20 min at room temperature to ensure that the resin and solution are fully mixed. S3. Under light-proof or yellow light conditions, continue to add photoinitiator and continue stirring at a speed of 300-500 r / min for 10-15 min to ensure that the photoinitiator is completely dissolved and uniformly dispersed. S4, then add 1,6-hexanediol diacrylate and ethoxynonylphenol acrylate, mix and stir until homogeneous, then add solvent and stir until homogeneous. S5, continue adding fumed silica, while increasing the stirring speed to 800-1200 r / min. After stirring for 20 min, reduce the stirring speed to 300-500 r / min, then add the silicone leveling agent and continue stirring for 5-10 min until homogeneous. S6. Degas the mixture obtained in S4 under a vacuum of -0.08 to -0.1 MPa for 10-15 minutes, let it stand to defoam, and then filter to obtain the adhesion-promoting coating liquid.

3. The encapsulated microprism reflective film according to claim 2, characterized in that: The solid content of the adhesive coating liquid is 40-60%, and the viscosity is 100-500 mPa·s.

4. The encapsulated microprism reflective film according to claim 2, characterized in that: The photoinitiator is composed of photoinitiator 1173 and photoinitiator TPO in a mass ratio of 3:

2.

5. The encapsulated microprism reflective film according to claim 2, characterized in that: The solvent is ethyl acetate or butanone.

6. The encapsulated microprism reflective film according to claim 1, characterized in that: The encapsulation layer comprises the following raw materials in parts by weight: 45-55 parts aliphatic polyurethane acrylate, 8-12 parts polyether polyurethane acrylate, 10-20 parts trifluoroethyl methacrylate, 8-15 parts ethoxyethoxyethyl acrylate, 3-8 parts tricyclodecanediethanol diacrylate, 1-2 parts 1-hydroxycyclohexylphenyl ketone, 0.5-1.5 parts phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide, 1-3 parts phosphate-modified acrylate, 1-3 parts polyamide wax, 0.3-0.8 parts antioxidant, and 15-25 parts ethyl acetate.

7. The encapsulated microprism reflective film according to claim 6, characterized in that: The encapsulation layer is formed by curing an encapsulation layer coating liquid, and the preparation method of the encapsulation layer coating liquid is as follows: A. At room temperature, aliphatic polyurethane acrylate, polyether polyurethane acrylate, trifluoroethyl methacrylate, ethoxyethoxyethyl acrylate and tricyclodecanediethanol diacrylate are added sequentially to a stirred tank and stirred at 300-500 r / min for 15-20 min to ensure that the components are mixed evenly to obtain a resin premix. B. Under light-protected or yellow light conditions, add 1-hydroxycyclohexylphenyl ketone and phenyl bis(2,4,6-trimethylbenzoyl)phosphine oxide to the resin premix, and continue stirring at 300-500 r / min for 15-20 min to ensure that the components are mixed evenly to obtain the premix. C. Continue adding phosphate-modified acrylate and antioxidant to the premix, and continue stirring for 10-15 minutes until homogeneous to obtain the mixture; D. Add a portion of ethyl acetate to the mixture obtained in step C, stir until homogeneous, add polyamide wax, increase the stirring speed to 800-1200 r / min, heat to 40-50℃, continue stirring for 20-30 min, then add the remaining ethyl acetate, reduce the stirring speed to 300-500 r / min, continue stirring for 10-15 min, and cool to room temperature. E. Degas the mixture obtained in step D under a vacuum of -0.08 to -0.1 MPa for 10-15 minutes, and then filter to obtain the encapsulation layer coating liquid.

8. The encapsulated microprism reflective film according to claim 6, characterized in that: The solid content of the coating liquid for the encapsulation layer is 50-60%, and the viscosity is 200-400 mPa·s.

9. The preparation process of the encapsulated microprism reflective film according to claim 1, characterized in that: Includes the following steps: Step 1: Corona treatment is performed on the substrate. The UV resin of the microprism layer is coated on the surface of the substrate. Then, the mold belt with the microprism structure is aligned with the substrate and fed into the elastic mirror steel roller. The temperature of the steel roller is controlled at 65°C and the pressure is 6MPa. The UV resin is pressed into the microprism structure of the mold belt. Then, it is cured under nitrogen protection. After complete curing, the mold belt is peeled off to form the microprism layer. Step 2: Apply the protective layer slurry to the other side of the substrate and cure to form a protective layer; Step 3: Perform corona treatment on the side of the support layer and the encapsulation layer that are opposite to each other, then apply an adhesion-promoting coating liquid to its surface, dry it at 80-100℃ for 1-3 minutes, and then cure it under nitrogen protection with ultraviolet light to form an adhesion-promoting layer with a thickness of 2-5 μm. Step 4: Apply the encapsulation layer coating liquid to the surface of the adhesion-promoting layer described in step 3, then dry it at 80-100°C for 1-3 minutes, and then cure it under ultraviolet light under nitrogen protection to form the encapsulation layer. Step 5: The materials obtained in Step 2 and Step 4 are passed through a pressure roller, which causes the microprism layer with the prism structure facing down and the encapsulation layer to be hot-pressed and bonded together at high temperature. The temperature of the pressure roller is 160-180℃ and the pressure is 0.1-0.3MPa. Step 6: Perform corona treatment on the other side of the support layer, then take a pressure-sensitive adhesive layer with a release layer, and composite the pressure-sensitive adhesive layer with the support layer. After composite, roll it up and let it stand for 24 hours to obtain the encapsulated microprism reflective film.

10. The preparation process of the encapsulated microprism reflective film according to claim 9, characterized in that: In step 1, during UV resin curing, the UV curing energy is controlled at 1200 mJ / cm². 2 In step 3, during the curing of the tack-promoting coating liquid, the UV curing energy is controlled at 800 mJ / cm². 2 In step 4, during the curing of the encapsulation layer coating liquid, the UV curing energy is controlled at 1000 mJ / cm². 2 .

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