An ultraviolet light-curable composition for a cross-hatch structured prism film and a method of preparing the same

Abstract

The present application relates to the technical field of optical ultraviolet light curing glue preparation, and particularly relates to an ultraviolet light curing composition for a cross structure prism film and a preparation method thereof. The ultraviolet light curing composition for the cross structure prism film is prepared from a high-activity acrylate oligomer composition, a UV active diluent composition and a photoinitiator composition; the high-activity acrylate oligomer composition comprises sulfur-containing polyurethane modified acrylate; sulfur elements are introduced into the main chain of the sulfur-containing polyurethane modified acrylate and / or mercapto-containing side chains are grafted on the main chain of the polyurethane modified acrylate, so that the overall photocuring rate of the ultraviolet light curing composition is improved, the ultraviolet light curing composition can be completely cured at normal machine speed, the prism microstructure on the surface of the UV prism glue film after the soft mold is stripped is relatively complete without obvious damage, and the UV prism glue film has good refractive index and brightness performance.

Description

Technical Field

[0001] This invention relates to the field of optical ultraviolet curable adhesive preparation technology, and in particular to an ultraviolet curable composition for a cross-striped prism film and its preparation method. Background Technology

[0002] Optical films have been widely used in the fields of optics and optoelectronics. In backlight modules such as LCD displays, prism films are used to focus the light emitted by the light source, increase display brightness, and save energy of the display battery.

[0003] The existing prism film production process is as follows: the existing UV prism adhesive is scraped onto the substrate film, and then rolled and laminated with a soft mold with prism microstructure on the surface. After the composite film is cured by UV light curing system, the substrate film with prism microstructure on the surface is peeled off and recycled to obtain the prism film. The prism film is composed of the substrate film and the UV prism adhesive film with prism microstructure on the surface.

[0004] The challenge in existing production processes lies in the peeling and recycling of soft molds with prism microstructures on their surfaces. On one hand, it's crucial to maintain the integrity of the horizontal striations (prism microstructures) on the UV prism film surface, as this integrity determines the brightening effect and optical luminance of the prism film. On the other hand, the recycled soft mold structure retains cured UV prism adhesive residue, affecting secondary recycling. Soft molds containing residual cured UV prism adhesive residue require a surface cleaning process to remove it, meeting the requirements for secondary use of the prism film. However, the cleaning process necessitates the use of organic solvents, placing high demands on the chemical solvent resistance of the soft mold. Furthermore, the use of organic solvents introduces volatile pollution issues, leading to high production costs for prism films and limiting the development of prism film soft film molding technology.

[0005] Reducing the amount of cured UV prism adhesive residue on the soft mold while ensuring the integrity of the horizontal striation structure (prism microstructure) on the surface of the UV prism film has become a technical bottleneck in the prism film soft molding process. In existing prism film soft molding processes, the normal machine speed of the composite film input into the UV curing system is generally 14-16 m / min. After the soft mold is released and peeled off, the prism microstructure on the surface of the UV prism film is incomplete.

[0006] To address the issue of incomplete prism microstructure on the surface of UV prism adhesive films at normal machine speeds, existing techniques involve adjusting the machine speed input to the UV curing system from 14-16 m / min to a low-to-medium speed of 6-8 m / min, thus extending the UV curing time and allowing the UV prism adhesive to fully cure, thereby improving the integrity of the horizontal stripe structure on the UV prism adhesive film surface to some extent. However, a slow machine speed directly impacts the production efficiency of prism films, and extending the UV exposure time accelerates the UV aging of the soft mold, shortens its recycling lifespan, increases the cost of the prism film, and limits its large-scale development. Therefore, the inventors provide a UV-curable composition for horizontal stripe structure prism films and its preparation method. Summary of the Invention

[0007] To address the technical problems of slow machine speed affecting production efficiency and prolonged UV exposure time exacerbating UV aging of the soft mold, shortening its recycling lifespan, and increasing the production cost of prism films in existing soft film molding processes, this invention provides a UV-curable composition for ribbed prism films and its preparation method.

[0008] The present invention provides a UV-curable composition for a ribbed prism film, which is achieved through the following technical solution:

[0009] A UV-curable composition for a ribbed prism film comprises a highly reactive acrylate oligomer composition, a UV-reactive diluent composition, a photoinitiator composition, and a non-silicone release agent; wherein the UV-reactive diluent composition accounts for 75-92 wt% of the UV-curable composition; the photoinitiator composition accounts for 2-6 wt% of the UV-curable composition; the non-silicone release agent accounts for 0.1-1 wt% of the UV-curable composition; and the highly reactive acrylate oligomer composition accounts for 3-12 wt% of the UV-curable composition; wherein the highly reactive acrylate oligomer composition includes at least a sulfur-containing polyurethane-modified acrylate, wherein the main chain of the sulfur-containing polyurethane-modified acrylate contains sulfur and / or thiol-containing side chains are grafted onto the main chain of the sulfur-containing polyurethane-modified acrylate.

[0010] In this invention, the sulfur atoms in the sulfur-modified polyurethane acrylate have a strong refractive power, which can improve the overall refractive index and luminance performance of the prism film. Furthermore, it can disrupt the original conjugated structure in the polyurethane soft segments, thereby reducing the light absorption capacity of the formed UV prism film and improving its light transmittance. In addition, the non-conjugated structure formed by the sulfur atoms and carbon chains in the polyurethane soft segments enhances the flexibility of the UV prism film, and the non-polar bonds formed by the sulfur atoms and carbon atoms reduce the dispersion effect of the UV prism film. This is beneficial for light propagation in the material and maintaining high light transmittance. It also improves the prism microstructure on the surface of the UV prism film after release from the soft mold, ensuring its integrity and preventing significant damage. This gives it excellent processing properties.

[0011] In this invention, a sulfur-containing polyurethane modified acrylate is grafted with a thiol-containing side chain onto its main chain. The thiol-SH group in the thiol-containing side chain undergoes a thiol-double bond click reaction with the unsaturated double bond under the action of a photoinitiator (free radical initiator). By controlling the content of the sulfur-containing polyurethane modified acrylate with thiol-containing side chains grafted onto the main chain, the overall photocuring rate of the UV-curable composition can be adjusted and improved. The prepared UV-curable composition meets the requirement of complete curing at normal machine speed. The prism microstructure on the surface of the UV prism film after release from the soft mold is relatively intact without obvious damage, and it is endowed with good refractive index and luminance properties. This solves the bottleneck problem of low production efficiency and high production cost in the existing soft film molding process of prism film.

[0012] Preferably, the sulfur-containing polyurethane modified acrylate is made from isocyanate, polyol, hydroxy acrylate, polymerization inhibitor, catalyst, and organic solvent; the molar ratio of the -NCO functional group in the isocyanate to the hydroxyl group in the polyol is (1.3-2.0):1; the polyol main chain contains sulfur and / or the polyol main chain is grafted with mercapto-containing side chains; the isocyanate is diisocyanate and / or triisocyanate; the hydroxy acrylate is hydroxyethyl acrylate and / or hydroxypropyl acrylate; the polymerization inhibitor is hydroquinone HQ and / or p-hydroxyanisole MEHQ; the catalyst is an organotin catalyst or a titanate catalyst; the organotin catalyst is at least one of dibutyltin dilaurate and stannous octoate; the titanate catalyst is at least one of tetrabutyl titanate and tetraisopropyl titanate; the organic solvent is at least one of toluene, acetone, ethyl acetate, N,N-dimethylformamide, methyl ethyl ketone, and dimethyl carbonate.

[0013] Preferably, the isocyanate is one or more of toluene diisocyanate, phenyl diisocyanate, and tris(4-phenylisocyanate) thiophosphate.

[0014] In this invention, isocyanates containing benzene rings are used as raw materials for the synthesis of sulfur-containing polyurethane modified acrylates. On the one hand, the high -NCO activity of isocyanates containing benzene rings facilitates the efficient synthesis of sulfur-containing polyurethane modified acrylates at 80°C; on the other hand, it can ensure the high refractive index and brightness performance of UV prism films.

[0015] Preferably, the polyol comprises a sulfur-containing polyol, which is prepared from phthalic acid, sulfur-containing diol, and small molecule diol; the phthalic acid is one or more combinations of biphenyl acid, terephthalic acid, phthalic acid, isophthalic acid, 2,3-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 1,4-naphthalenedicarboxylic acid, and 2,7-naphthalenedicarboxylic acid; the small molecule diol is one or more combinations of ethylene glycol, 1,3-propanediol, 1,2-propanediol, dipropylene glycol, trimerized 1,2-propanediol, 1,4-butanediol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, 1,6-hexanediol, phthalic acid, terephthalic acid, and isophthalic acid.

[0016] Preferably, the sulfur-containing diol is one or a combination of 2,2-thiodiethanol, 2,2'-dithiodiethanol, and 3,3'-thiodipropanol.

[0017] The sulfur-containing polyurethane modified acrylate prepared by using at least one of 2,2-thiodiethanol, 2,2'-dithiodiethanol, and 3,3'-thiodipropanol as a sulfur-containing diol has a main chain containing sulfur atoms, which can improve the overall flexibility, high light transmittance, processability, refractive index, and luminance performance of the prism film.

[0018] Preferably, the polyol comprises a sulfur-containing polyol, which is prepared from a polyether glycol with a molecular weight of 300-1000 and a mercapto-containing diacid; the mercapto-containing diacid is mercaptosuccinic acid and / or dimercaptosuccinic acid; the polyether glycol with a molecular weight of 300-1000 is one or a combination of polyethylene glycol, polypropylene glycol, polytetrahydrofuran glycol, and branched polytetrahydrofuran glycol.

[0019] The sulfur-containing polyol prepared from polyether glycol and mercapto-diacid in this invention exhibits superior flexibility and water resistance in the resulting sulfur-containing polyurethane-modified acrylate. Furthermore, the grafted thiol groups on the main chain enhance the overall UV curing rate of the UV-curable composition and optimize the overall flexibility, light transmittance, processability, refractive index, and luminance of the prism film. In addition, the ester bond content in the sulfur-containing polyurethane-modified acrylate is lower than that of the other two types of sulfur-containing polyurethane-modified acrylates. While maintaining the adhesion strength between the UV prism film and the substrate, this reduces the adhesion strength between the soft mold and the UV prism film, facilitating mold release and ensuring the prism microstructure on the UV prism film surface remains relatively intact without significant damage.

[0020] Preferably, the method for preparing the sulfur-containing polyurethane-modified acrylate is as follows:

[0021] S1. Preparation of polyols;

[0022] S2. The polyol is placed under vacuum at 110-125℃ for 1-2 hours to dehydrate. The temperature is then adjusted to 60-75℃. The dehydrated polyol is mixed with a precisely measured amount of isocyanate, organotin catalyst, and organic solvent. The reaction is maintained at 60-75℃ until the -NCO content in the system reaches the theoretical value, thus obtaining an isocyanate-terminated polyurethane prepolymer.

[0023] S3. Add polymerization inhibitor and titanate catalyst to isocyanate-terminated polyurethane prepolymer, mix evenly, and then add hydroxy acrylate. Maintain the temperature at 60-75℃ for esterification and termination reaction for 30-90 minutes. Detect the -NCO content of the product in the reactor and find it to be 0. Then remove the organic solvent by vacuum distillation to obtain sulfur-containing polyurethane modified acrylate.

[0024] The preparation method of sulfur-containing polyurethane modified acrylate in this invention is mature and relatively simple to operate, which facilitates industrial-scale manufacturing, reduces the production cost of sulfur-containing polyurethane modified acrylate, and thus helps to optimize the overall production cost of UV-curable composition for prism film with horizontal stripe structure.

[0025] Preferably, the UV reactive diluent composition comprises a monofunctional UV reactive diluent and a difunctional UV reactive diluent; the monofunctional UV reactive diluent is at least one selected from o-phenylphenoxyethyl acrylate, 2-phenoxyethyl methacrylate, 2-phenoxyethyl acrylate, 2-phenylthioethanol acrylate, and ethyl 4-mercaptocinnamate; the difunctional UV reactive diluent is at least one selected from bisphenol A glycerol dimethacrylate, bisphenol A ethoxydiacrylate, and bisphenol A diallyl ether.

[0026] By adopting the above technical solution, the high refractive index and luminance performance of the UV prism film formed under normal machine speed of UV curing composition can be guaranteed. In addition, the bifunctional UV active diluent can adjust the crosslinking density of the UV prism film, ensuring that the mechanical properties of the UV prism film and the prism microstructure on the surface of the UV prism film are relatively intact and without obvious damage after the soft mold is released and peeled off, thereby improving the overall yield of the prism film.

[0027] Preferably, the photoinitiator composition is at least one of photoinitiator 2959, photoinitiator 184, photoinitiator TPO, photoinitiator 1173, and photoinitiator DETX.

[0028] More preferably, the photoinitiator composition is photoinitiator 184 or photoinitiator TPO.

[0029] The photoinitiator composition preferred in this invention can improve the photocuring efficiency of the UV curing composition and ensure that the UV prism film formed by the UV curing composition is cured at normal machine speed.

[0030] Preferably, the non-silicone release agent is a fluorinated release agent.

[0031] In this invention, a fluorinated release agent is used to reduce the bonding strength between the soft mold and the UV prism film, making it easier to release and peel off the soft mold, and ensuring that the prism microstructure on the surface of the UV prism film is relatively intact without obvious damage.

[0032] The present invention provides a method for preparing a UV-curable composition for a ribbed prism film, which is achieved through the following technical solution:

[0033] A method for preparing a UV-curable composition for a ribbed prism film includes the following steps: first, preparing a highly reactive acrylate oligomer composition; then, in a light-protected environment, mixing the accurately measured highly reactive acrylate oligomer composition, UV-reactive diluent composition, and non-silicone release agent evenly; finally, under nitrogen protection, adding a photoinitiator composition, mixing evenly, discharging, and vacuum packaging to obtain the UV-curable composition for the ribbed prism film.

[0034] In summary, the present invention has the following advantages:

[0035] 1. The UV curing composition of the present invention has a high curing rate and can be completely cured at normal machine speed. The prism microstructure on the surface of the UV prism film after the soft mold is released is relatively intact without obvious damage. In addition, the UV prism film has the advantages of high refractive index, high brightness performance and high light transmittance.

[0036] 2. The UV prism film formed by the UV curing composition of the present invention after complete curing at normal machine speed has good mechanical properties and flexibility. The prism microstructure on the surface of the UV prism film after release from the soft mold is more complete and has better performance with no obvious damage, which can improve the processing performance of the prism film.

[0037] 3. The preparation method of the present invention is mature and relatively simple to operate, which facilitates industrial-scale manufacturing and reduces the overall production cost of the UV curing composition for prism film with horizontal stripe structure. Attached Figure Description

[0038] Figure 1 This is a diagram illustrating the surface prism microstructure of the UV prism film formed by UV curing the UV curing composition in Example 1 of this invention.

[0039] Figure 2This is a diagram illustrating the surface prism microstructure of the UV prism film formed by UV curing the UV curing composition in Comparative Example 1 of this invention. Detailed Implementation

[0040] To further understand the inventiveness and technical contributions of this invention, the following description, in conjunction with embodiments, comparative examples, and appendices, is provided. Figure 1-2 The preferred embodiments of the present invention will be discussed in detail.

[0041] Example: A UV-curable composition for a ribbed prism film comprises a highly reactive acrylate oligomer composition, a UV-reactive diluent composition, a photoinitiator composition, and a non-silicone release agent.

[0042] The UV reactive diluent composition comprises 75-92 wt% of the UV curing composition. The UV reactive diluent composition includes monofunctional and difunctional UV reactive diluents. The monofunctional UV reactive diluent is at least one selected from o-phenylphenoxyethyl acrylate, 2-phenoxyethyl methacrylate, 2-phenoxyethyl acrylate, 2-phenylthioethanol acrylate, and ethyl 4-mercaptocinnamate. The difunctional UV reactive diluent is at least one selected from bisphenol A glycerol dimethacrylate, bisphenol A ethoxydiacrylate, and bisphenol A diallyl ether.

[0043] The photoinitiator composition comprises 2-6 wt% of the UV-curable composition. The photoinitiator composition is at least one selected from photoinitiator 2959, photoinitiator 184, photoinitiator TPO, photoinitiator 1173, and photoinitiator DETX. Preferably, the photoinitiator composition is photoinitiator 184 or photoinitiator TPO.

[0044] The UV reactive diluent composition comprises 75-92 wt% of the UV curing composition.

[0045] The non-silicone release agent accounts for 0.1-1 wt% of the UV-curable composition. The non-silicone release agent is a fluorinated release agent.

[0046] The highly reactive acrylate oligomer composition accounts for 3-12 wt% of the UV-curable composition.

[0047] The highly reactive acrylate oligomer composition includes at least a sulfur-containing polyurethane-modified acrylate, wherein the main chain of the sulfur-containing polyurethane-modified acrylate contains sulfur and / or a mercapto-containing side chain is grafted onto the main chain of the sulfur-containing polyurethane-modified acrylate.

[0048] Sulfur-containing polyurethane modified acrylate is made from isocyanate, polyol, hydroxy acrylate, polymerization inhibitor, catalyst, and organic solvent. The molar ratio of the -NCO functional group in the isocyanate to the hydroxyl group in the polyol is (1.3-2.0):1.

[0049] The isocyanate is a diisocyanate and / or a triisocyanate. Specifically, the isocyanate is one or more combinations of toluene diisocyanate, phenylene diisocyanate, and tris(4-phenylisocyanate) thiophosphate.

[0050] The hydroxy acrylate is hydroxyethyl acrylate and / or hydroxypropyl acrylate.

[0051] The polymerization inhibitors are hydroquinone HQ and / or p-hydroxyanisole MEHQ.

[0052] The catalyst is an organotin catalyst or a titanate catalyst. Specifically, the organotin catalyst is at least one of dibutyltin dilaurate and stannous octoate, and the titanate catalyst is at least one of tetrabutyl titanate and tetraisopropyl titanate.

[0053] The organic solvent is at least one of toluene, acetone, ethyl acetate, N,N-dimethylformamide, methyl ethyl ketone, and dimethyl carbonate.

[0054] The polyol backbone contains sulfur and / or the polyol backbone is grafted with thiol-containing side chains.

[0055] The polyol is a sulfur-containing polyol, and there are two methods for synthesizing sulfur-containing polyols:

[0056] The first type: sulfur-containing polyols include those containing phthalic acid, mercaptodiols, and small molecule diols.

[0057] The phthalic acid is one or more combinations of biphenyl acid, terephthalic acid, phthalic acid, isophthalic acid, 2,3-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 1,4-naphthalenedicarboxylic acid, and 2,7-naphthalenedicarboxylic acid. The mercaptodiol is one or more combinations of 2,2-thiodiethanol, 2,2'-dithiodiethanol, and 3,3'-thiodipropanol. The small molecule diol is one or more combinations of ethylene glycol, 1,3-propanediol, 1,2-propanediol, dipropylene glycol, trimerized 1,2-propanediol, 1,4-butanediol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, 1,6-hexanediol, phthalic acid, terephthalic acid, and isophthalic acid.

[0058] The second type: sulfur-containing polyols include polyether diols with a molecular weight of 300-1000 and mercapto-dicarboxylic acid.

[0059] The mercaptodiic acid is mercaptosuccinic acid and / or dimercaptosuccinic acid.

[0060] Polyether glycols with a molecular weight of 300-1000 are one or more combinations of polyethylene oxide glycol, polypropylene oxide glycol, polytetrahydrofuran glycol, and branched polytetrahydrofuran glycol.

[0061] The preparation method of sulfur-containing polyurethane modified acrylate is as follows:

[0062] S1. Preparation of polyols;

[0063] S2. The polyol is placed under vacuum at 110-125℃ for 1-2 hours to dehydrate. The temperature is then adjusted to 60-75℃. The dehydrated polyol is mixed with a precisely measured amount of isocyanate, organotin catalyst, and organic solvent. The reaction is maintained at 60-75℃ until the -NCO content in the system reaches the theoretical value, thus obtaining an isocyanate-terminated polyurethane prepolymer.

[0064] S3. Add polymerization inhibitor and titanate catalyst to the isocyanate-terminated polyurethane prepolymer, mix evenly, and then add hydroxy acrylate. Maintain the temperature at 60-75℃ for esterification and termination reaction for 30-90 minutes. Detect that the -NCO content of the product in the reactor is 0. Then remove the organic solvent by vacuum distillation to obtain sulfur-containing polyurethane modified acrylate.

[0065] The method for measuring -NCO content is as follows: refer to the standard GB / T12009.4-89, that is, -NCO reacts with di-n-butylamine to form urea, and the -NCO content is measured by calibration with hydrochloric acid solution.

[0066] A method for preparing a UV-curable composition for a ribbed prism film includes the following steps: first, preparing a highly reactive acrylate oligomer composition; then, in a light-protected environment, mixing the accurately measured highly reactive acrylate oligomer composition, UV-reactive diluent composition, and non-silicone release agent evenly; finally, under nitrogen protection, adding a photoinitiator composition, mixing evenly, discharging, and vacuum packaging to obtain the UV-curable composition for the ribbed prism film.

[0067] Preparation Example 1: The preparation method of sulfur-containing polyurethane modified acrylate is as follows:

[0068] S1. Preparation of sulfur-containing polyols:

[0069] S1.1. Under nitrogen protection, 216.2 g (1.0 mol) of 1,4-naphthalenedicarboxylic acid (molecular weight 216.189, CAS: 605-70-9, Maclean), 37.56 g (0.25 mol) of 3,3'-thiodipropanol (molecular weight 150.239, CAS: 10595-09-2, Adamas / Titan), and 34.54 g (0.25 mol) of phthalic acid (CAS: 612-14-6, molecular weight 138.164, West Asia Reagent), 63.82g (0.54mol) of 3-methyl-1,5-pentanediol (molecular weight 118.174, CAS:4457-71-0, Maclean) and 2g of antioxidant 1010 (CAS:6683-19-8, Maclean) were added to a reaction vessel, heated to 135℃, and reacted for 3h. Then, the temperature was increased to 230℃ at a constant rate over 4h, and reacted for 3h.

[0070] S1.2. The temperature at the top of the distillation column was controlled at 102±0.5℃. After 1 hour of reaction, a sample was taken to measure the acid value of the reactants in the reactor. When the acid value was ≤30mgKOH / g, 0.2g of tetrabutyl titanate (CAS:5593-70-4, Adamas / Titan) was added and a vacuum was drawn. Within 4 hours, the pressure inside the reactor was gradually drawn from atmospheric pressure to 10Pa. A sample was taken to measure the hydroxyl value of the reactants in the reactor. When the hydroxyl value of the reactants in the reactor was between 112-114mgKOH / g, nitrogen was then used to break the vacuum and the temperature was lowered to 110℃. Finally, the reactor was cooled to below 35℃ in a water bath, and the product was unloaded and packaged to obtain sulfur-containing polyol. The measured hydroxyl value of the obtained sulfur-containing polyol was 112.4mgKOH / g.

[0071] S2. Take 100g of the sulfur-containing polyol from S1.2 and place it in a reaction vessel. Heat the mixture to 120℃ and dehydrate it under vacuum for 2 hours. Then, break the vacuum with nitrogen and cool the mixture to 75℃. Add 34.84g of toluene diisocyanate TDI (Yantai Wanhua, CAS: 26471-62-5, molecular weight 174.16), 0.005g of dibutyltin dilaurate, and 65g of acetone to the reaction vessel and mix them evenly. Maintain the reaction at 75℃ for 2 hours. Take a sample to test the -NCO content of the reactants in the reaction vessel until the -NCO content in the reactants reaches the theoretical value to obtain isocyanate-terminated polyurethane prepolymer.

[0072] S3. Adjust the temperature of the isocyanate-terminated polyurethane prepolymer in the reactor to 70℃. Add 0.3g of polymerization inhibitor hydroquinone (CAS: 123-31-9, Maclean) and 0.8g of tetrabutyl titanate (CAS: 5593-70-4, Adamas) to the reactor. Mix well and then add 24.38g of hydroxyethyl acrylate (molecular weight 116.12, CAS: 818-61-1, Aladdin). Esterification and end-capping reaction is carried out at 70℃ for 1 hour. Samples are taken to detect the -NCO content of the reactants in the reactor. After the -NCO content of the reactants in the reactor is detected to be 0, the organic solvent - acetone is removed by vacuum distillation. After cooling and unloading, sulfur-containing polyurethane modified acrylate is obtained.

[0073] Preparation Example 2: The preparation method of sulfur-containing polyurethane modified acrylate is as follows:

[0074] S1. The preparation of sulfur-containing polyols is as follows: Under nitrogen protection, 40.20g of polypropylene glycol PPG-200 from Hubei Watson Chemical Technology Co., Ltd. and 18.22g of dimercaptosuccinic acid (CAS: 304-55-2, molecular weight 182.22, Adamas / Titan) were added to a reaction vessel and mixed evenly. Then, 0.1g of tetrabutyl titanate was added and the temperature was raised to 60℃ for esterification reaction for 2h. Subsequently, the sulfur-containing polyols were obtained by dehydration and filtration using 4A molecular sieve powder.

[0075] S2. Take 52.8g of sulfur-containing polyol from S1 and place it in a reaction vessel. Add 34.84g of toluene diisocyanate (TDI), 0.005g of dibutyltin dilaurate, and 72g of acetone to the reaction vessel and mix well. Heat to 75℃ and maintain the temperature at 75℃ for 2 hours. Take a sample to detect the -NCO content of the reactants in the reaction vessel until the -NCO content in the reactants reaches the theoretical value to obtain isocyanate-terminated polyurethane prepolymer.

[0076] S3. Adjust the temperature of the isocyanate-terminated polyurethane prepolymer in the reactor to 70°C. Add 0.3g hydroquinone and 0.8g tetrabutyl titanate to the reactor and mix well. Then add 24.38g hydroxyethyl acrylate and maintain the esterification and termination reaction at 70°C for 1 hour. Take a sample to test the -NCO content of the reactants in the reactor. The -NCO content of the reactants in the reactor is 0. Then remove acetone by vacuum distillation and cool and unload to obtain sulfur-containing polyurethane modified acrylate.

[0077] The difference between Preparation Example 3 and Preparation Example 1 is that the preparation method of polyurethane-modified acrylate is as follows:

[0078] S1. Preparation of polyols:

[0079] S1.1. Under nitrogen protection, 216.2 g (1.0 mol) of 1,4-naphthalenedicarboxylic acid, 29.54 g (0.25 mol) of 1,6-hexanediol (molecular weight 118.174, CAS: 629-11-8, West Asia Reagent), 34.54 g (0.25 mol) of o-phthalic acid, 63.82 g (0.54 mol) of 3-methyl-1,5-pentanediol, and 2 g of antioxidant 1010 were added to a reaction vessel, stirred well, and then heated to 135 °C and kept at that temperature for 3 h. Subsequently, the temperature was uniformly increased to 230 °C and kept at that temperature for 3 h over 4 h.

[0080] S1.2. Control the temperature at the top of the distillation column to 102±0.5℃. After reacting for 1 hour, take a sample to measure the acid value of the reactants. When the acid value is ≤30mgKOH / g, add 0.2g of tetrabutyl titanate and evacuate the vacuum. Within 4 hours, gradually reduce the pressure inside the vessel from atmospheric pressure to 10Pa. Take a sample to measure the hydroxyl value of the reactants inside the vessel. When the hydroxyl value of the reactants inside the vessel is between 112-114mgKOH / g, then break the vacuum with nitrogen and cool down to 110℃. Finally, cool down to below 35℃ in a water bath, unload and package to obtain sulfur-containing polyol. The measured hydroxyl value of the obtained sulfur-containing polyol is 112.3mgKOH / g.

[0081] S2. Take 100g of the polyol from S1.2 and place it in a reaction vessel. Heat it to 120℃ and dehydrate it under vacuum for 2 hours. Then, break the vacuum with nitrogen and cool it to 75℃. Add 34.84g of toluene diisocyanate (TDI), 0.005g of dibutyltin dilaurate, and 65g of acetone to the reaction vessel and mix them evenly. Maintain the reaction at 75℃ for 2 hours. Take a sample to detect the -NCO content of the reactants in the reaction vessel until the -NCO content in the reactants reaches the theoretical value to obtain isocyanate-terminated polyurethane prepolymer.

[0082] S3. Adjust the temperature of the isocyanate-terminated polyurethane prepolymer in the reactor to 70°C. Add 0.3g of hydroquinone and 0.8g of tetrabutyl titanate to the reactor and mix well. Then add 24.38g of hydroxyethyl acrylate. Maintain the temperature at 70°C and perform the esterification and termination reaction for 1 hour. Take a sample to test the -NCO content of the reactants in the reactor. The -NCO content of the reactants in the reactor is 0. Then remove the organic solvent -acetone by vacuum distillation. Cool and unload to obtain sulfur-containing polyurethane modified acrylate.

[0083] The difference between Preparation Example 4 and Preparation Example 2 is that the preparation method of polyurethane-modified acrylate is as follows:

[0084] S1. The preparation of polyol is as follows: Under nitrogen protection, 40.20g of polypropylene glycol PPG-200 and 11.82g of succinic acid (CAS: 110-15-6, molecular weight 118.09, Adamas / Titan) were added to a reaction vessel and mixed evenly. Then, 0.1g of tetrabutyl titanate was added and the temperature was raised to 60℃ for esterification reaction for 2.0h. The polyol was obtained by dehydration and filtration using zeolite powder.

[0085] S2. Take 48.3g of the polyol from S1 and place it in a reaction vessel. Heat it to 120℃ and dehydrate it under vacuum for 2 hours. Then, break the vacuum with nitrogen and cool it to 75℃. Add 34.84g of toluene diisocyanate (TDI), 0.005g of dibutyltin dilaurate, and 72g of acetone to the reaction vessel and mix them evenly. Heat it to 75℃ and maintain the temperature at 75℃ for 2 hours. Take a sample to detect the -NCO content of the reactants in the vessel. The -NCO content of the reactants in the vessel reaches the theoretical value, and the isocyanate-terminated polyurethane prepolymer is obtained.

[0086] S3. Adjust the temperature of the isocyanate-terminated polyurethane prepolymer in the reactor to 70°C. Add 0.3g hydroquinone and 0.8g tetrabutyl titanate to the reactor and mix well. Then add 24.38g hydroxyethyl acrylate. Maintain the temperature at 70°C and perform the esterification and termination reaction for 1 hour. Take a sample to test the -NCO content of the reactants in the reactor. The -NCO content of the reactants in the reactor is 0. Then remove acetone by vacuum distillation and cool and unload to obtain sulfur-containing polyurethane modified acrylate.

[0087] The difference between Preparation Example 5 and Preparation Example 1 is that the preparation method of sulfur-containing polyurethane modified acrylate is different: S1. Preparation of sulfur-containing polyol: S1.1. Under nitrogen protection, 216.2 g (1.0 mol) of 1,4-naphthalenedicarboxylic acid, 38.56 g (0.25 mol) of 2-hydroxyethyl disulfide (Maclean, CAS: 1892-29-1, molecular weight 154.25), 34.54 g (0.25 mol) of phthalic acid, 63.82 g (0.54 mol) of 3-methyl-1,5-pentanediol and 2 g of antioxidant 1010 (CAS: 6683-19-8, Maclean) were added to the reaction vessel, heated to 135 °C and kept at that temperature for 3 h, and then heated to 230 °C at a uniform rate for 4 h and kept at that temperature for 3 h.

[0088] S1.2. Control the temperature at the top of the distillation column to 102±℃. After reacting for 1 hour, take a sample to measure the acid value of the reactants. When the acid value is ≤30mgKOH / g, add 0.2g of tetrabutyl titanate and evacuate the vacuum. Within 4 hours, gradually reduce the pressure inside the vessel from atmospheric pressure to 10Pa. Take a sample to measure the hydroxyl value of the reactants inside the vessel. When the hydroxyl value of the reactants inside the vessel is between 112-114mgKOH / g, then break the vacuum with nitrogen and cool down to 110℃. Finally, cool down to below 35℃ in a water bath, unload and package to obtain sulfur-containing polyol. The measured hydroxyl value of the obtained sulfur-containing polyol is 112.6mgKOH / g. The remaining steps are the same.

[0089] The difference between Preparation Example 6 and Preparation Example 1 is that the preparation method of sulfur-containing polyurethane modified acrylate is different in that: S2. 100g of the sulfur-containing polyol in S1.2 is placed in a reaction vessel, heated to 120°C and dehydrated under vacuum for 2h. Then, nitrogen is used to break the vacuum and the temperature is lowered to 75°C. 37.64g of phenylene diisocyanate XDI (CAS: 3634-83-1, molecular weight: 188.18, Maclean), 0.005g of dibutyltin dilaurate, and 72g of acetone are added to the reaction vessel and mixed evenly. The reaction is maintained at 75°C for 2h. The -NCO content of the reactants in the reaction vessel is measured. The -NCO content of the reactants in the vessel is 0. The product is cooled and discharged to obtain isocyanate-terminated polyurethane prepolymer. The remaining steps are the same.

[0090] The difference between Preparation Example 7 and Preparation Example 1 is that the preparation method of sulfur-containing polyurethane modified acrylate is different in that: S2. 100g of the sulfur-containing polyol in S1 is placed in a reaction vessel, heated to 120°C and dehydrated under vacuum for 2h, then the vacuum is broken by nitrogen and the temperature is lowered to 85°C. Under nitrogen protection, 139.62g of tris(4-phenylisocyanate) TPTI (CAS: 4151-51-3, molecular weight 465.375, Maclean), 0.005g of dibutyltin dilaurate, and 128g of acetone are added to the reaction vessel and mixed evenly. The reaction is maintained at 85°C for 1.5h. The -NCO content of the reactants in the vessel is measured until the -NCO content in the reactants in the vessel reaches the theoretical value, and the isocyanate-terminated polyurethane prepolymer is obtained.

[0091] S3. Adjust the temperature of the isocyanate-terminated polyurethane prepolymer in the reactor to 60℃. Add 0.5g of hydroquinone and 0.8g of tetrabutyl titanate to the reactor and mix well. Then add 34.84g of hydroxyethyl acrylate. Maintain the temperature at 60℃ and perform esterification and termination reaction for 90min. Take a sample to detect the -NCO content of the reactants in the reactor. The -NCO content of the reactants in the reactor is 0. Then remove acetone by vacuum distillation, cool and unload to obtain sulfur-containing polyurethane modified acrylate. The remaining steps are the same.

[0092] Example 1: A UV-curable composition for a ribbed prism film comprises the following raw materials in weight percentages: 8.0% sulfur-containing polyurethane modified acrylate from Preparation Example 1, 52.2% o-phenylphenoxyethyl acrylate (CAS: 91442-24-9, Maclean's), 30% bisphenol A ethoxylated diacrylate (CAS: 64401-02-1, Maclean's), 5% 2-phenoxyethyl acrylate (CAS: 48145-04-6, Jiangsu Bosite Chemical Technology Co., Ltd.), 4% photoinitiator 184 (1-hydroxycyclohexylphenyl ketone, CAS: 947-19-3, West Asia Reagent), 0.5% photoinitiator TPO (2,4,6-trimethylbenzoyl-diphenylphosphine oxide, CAS: 75980-60-8, West Asia Reagent), and 0.3% fluorinated release agent Q2-7785 (Wuhan Kemike Biomedical Technology Co., Ltd.).

[0093] A method for preparing a UV-curable composition for a ribbed prism film includes the following steps: Step 1, preparing a highly active acrylate oligomer composition, specifically referring to the preparation method of sulfur-containing polyurethane modified acrylate in Preparation Example 1; Step 2, under a light-protected environment, accurately measuring 8 parts by weight of sulfur-containing polyurethane modified acrylate from Preparation Example 1, 52 parts by weight of o-phenylphenoxyethyl acrylate, 30 parts by weight of bisphenol A ethoxylated diacrylate, 5 parts by weight of 2-phenoxyethyl acrylate, and 0.5 parts by weight of fluorinated release agent Q2-7785 are mixed evenly; Step 3, under nitrogen protection, adding 4 parts by weight of photoinitiator 184 and 0.5 parts by weight of photoinitiator TPO, mixing evenly, discharging, and vacuum packaging to obtain the UV-curable composition for the ribbed prism film.

[0094] The difference between Example 2 and Example 1 is that the UV-curable composition for the ribbed prism film comprises the following raw materials in weight percentages: 6% sulfur-containing polyurethane-modified acrylate from Example 1, 51.7% o-phenylphenoxyethyl acrylate (CAS: 91442-24-9, Maclean), 30.5% bisphenol A ethoxylated diacrylate (CAS: 64401-02-1, Maclean), and 5% 2-phenoxyethyl acrylate (CAS: 48145-04-6). Jiangsu Bosite Chemical Technology Co., Ltd.), 2% 2-phenylthioethanolacrylic acid (CAS: 95175-38-5, Guangdong Wengjiang Chemical Reagent Co., Ltd.), 4% photoinitiator 184 (1-hydroxycyclohexylphenyl ketone, CAS: 947-19-3, West Asia Reagent), 0.5% photoinitiator TPO (2,4,6-trimethylbenzoyl-diphenylphosphine oxide, CAS: 75980-60-8, West Asia Reagent), 0.3% fluorinated release agent Q2-7785.

[0095] The difference between Example 3 and Example 1 is that the UV-curable composition for the ribbed prism film comprises the following raw materials in the following mass percentages: 4% sulfur-containing polyurethane modified acrylate from Preparation Example 1, 51.2% o-phenylphenoxyethyl acrylate, 31% bisphenol A ethoxylated diacrylate, 5% 2-phenoxyethyl acrylate, 2% 2-phenylthioethanol acrylate, 2% ethyl 4-mercaptocinnamate (CAS: 1076198-07-6, Beijing Bailingwei Technology Co., Ltd.), 4% photoinitiator 184, 0.5% photoinitiator TPO, and 0.3% fluorinated release agent Q2-7785.

[0096] The difference between Example 4 and Example 1 is that the UV-curable composition for the ribbed prism film comprises the following raw materials in weight percentage: 4% sulfur-containing polyurethane modified acrylate from Preparation Example 1, 53.95% o-phenylphenoxyethyl acrylate, 31.25% bisphenol A ethoxylated diacrylate, 5% 2-phenoxyethyl acrylate, 5% photoinitiator 184, 0.5% photoinitiator TPO, and 0.3% fluorinated release agent Q2-7785.

[0097] The difference between Example 5 and Example 1 is that the UV-curable composition for the ribbed prism film comprises the following raw materials in weight percentage: 12% sulfur-containing polyurethane modified acrylate from Preparation Example 1, 49.7% o-phenylphenoxyethyl acrylate, 29% bisphenol A ethoxylated diacrylate, 5% 2-phenoxyethyl acrylate, 3.5% photoinitiator 184, 0.5% photoinitiator TPO, and 0.3% fluorinated release agent Q2-7785.

[0098] The difference between Example 6 and Example 1 is that the UV-curable composition for the ribbed prism film comprises the following raw materials in the following mass percentages: 8% sulfur-containing polyurethane modified acrylate from Preparation Example 2, 52.1% o-phenylphenoxyethyl acrylate, 30% bisphenol A ethoxylated diacrylate, 5% 2-phenoxyethyl acrylate, 4% photoinitiator 184, 0.5% photoinitiator TPO, and 0.4% fluorinated release agent Q2-7785.

[0099] The difference between Example 7 and Example 1 is that the UV-curable composition for the ribbed prism film comprises the following raw materials in the following mass percentages: 6% sulfur-containing polyurethane modified acrylate from Preparation Example 2, 2% sulfur-containing polyurethane modified acrylate from Preparation Example 1, 52.1% o-phenylphenoxyethyl acrylate, 30% bisphenol A ethoxylated diacrylate, 5% 2-phenoxyethyl acrylate, 4% photoinitiator 184, 0.5% photoinitiator TPO, and 0.4% fluorinated release agent Q2-7785.

[0100] The difference between Example 8 and Example 1 is that the UV-curable composition for the ribbed prism film comprises the following raw materials in weight percentage: 8% sulfur-containing polyurethane modified acrylate from Preparation Example 5, 52.2% o-phenylphenoxyethyl acrylate, 30% bisphenol A ethoxylated diacrylate, 5% 2-phenoxyethyl acrylate, 4% photoinitiator 184, 0.5% photoinitiator TPO, and 0.3% fluorinated release agent Q2-7785.

[0101] The difference between Example 9 and Example 1 is that the UV-curable composition for the ribbed prism film comprises the following raw materials in the following mass percentages: 8% sulfur-containing polyurethane modified acrylate from Preparation Example 6, 52.2% o-phenylphenoxyethyl acrylate, 30% bisphenol A ethoxylated diacrylate, 5% 2-phenoxyethyl acrylate, 4% photoinitiator 184, 0.5% photoinitiator TPO, and 0.3% fluorinated release agent Q2-7785.

[0102] The difference between Example 10 and Example 1 is that the UV-curable composition for the ribbed prism film comprises the following raw materials in the following mass percentages: 0.5% sulfur-containing polyurethane modified acrylate from Preparation Example 7, 7.5% sulfur-containing polyurethane modified acrylate from Preparation Example 1, 53.1% o-phenylphenoxyethyl acrylate, 29% bisphenol A ethoxylated diacrylate, 5% 2-phenoxyethyl acrylate, 4% photoinitiator 184, 0.5% photoinitiator TPO, and 0.4% fluorinated release agent Q2-7785.

[0103] The difference between Comparative Example 1 and Example 1 is that the UV-curable composition for the ribbed prism film comprises the following raw materials in weight percentage: 8% of the polyurethane modified acrylate from Preparation Example 3, 52.2% of o-phenylphenoxyethyl acrylate, 30% of bisphenol A ethoxylated diacrylate, 5% of 2-phenoxyethyl acrylate, 4% of photoinitiator 184, 0.5% of photoinitiator TPO, and 0.4% of fluorinated release agent Q2-7785.

[0104] The difference between Comparative Example 2 and Example 1 is that the UV-curable composition for the ribbed prism film comprises the following raw materials in weight percentages: 8% of the polyurethane-modified acrylate from Preparation Example 4, 52.2% of o-phenylphenoxyethyl acrylate, 30% of bisphenol A ethoxylated diacrylate, 5% of 2-phenoxyethyl acrylate, 4% of photoinitiator 184, 0.5% of photoinitiator TPO, and 0.3% of fluorinated release agent Q2-7785.

[0105] The difference between Comparative Example 3 and Example 1 is that the UV-curable composition for the ribbed prism film comprises the following raw materials in the following mass percentages: 1% of the polyurethane modified acrylate from Preparation Example 1, 7% of aromatic polyurethane acrylate SM6329 (relative molecular mass ~3000, Jiangsu Sanmu Group), 52.2% of o-phenylphenoxyethyl acrylate, 30% of bisphenol A ethoxylated diacrylate, 5% 2-phenoxyethyl acrylate, 4% photoinitiator 184, 0.5% photoinitiator TPO, and 0.3% fluorinated release agent Q2-7785.

[0106] The difference between Comparative Example 4 and Example 1 is that the UV-curable composition for the ribbed prism film comprises the following raw materials in the following mass percentages: 8% aromatic polyurethane acrylate SM6329 (relative molecular mass ~3000, Jiangsu Sanmu Group), 52.2% o-phenylphenoxyethyl acrylate, 30% ethylene glycol dimethacrylate (CAS: 97-90-5, Aladdin), 5% 2-phenoxyethyl acrylate, 4% photoinitiator 184, 0.5% photoinitiator TPO, and 0.3% fluorinated release agent Q2-7785.

[0107] The difference between Comparative Example 5 and Example 1 is that the UV-curable composition for the ribbed prism film comprises the following raw materials in the following mass percentages: 8% sulfur-containing polyurethane modified acrylate from Preparation Example 1, 52.2% o-phenylphenoxyethyl acrylate, 30% ethylene glycol dimethacrylate, 5% 2-phenoxyethyl acrylate, 4% photoinitiator 184, 0.5% photoinitiator TPO, and 0.3% fluorinated release agent Q2-7785.

[0108] Performance testing: The peel strength between the UV prism film (PET film / UV prism film) and the flexible mold was determined according to GB / T2790-2014 Test Method for Peel Strength of Adhesive Tapes. The prism composite film consists of a PET film (TOYOBOA optical grade polyester film A4360, 0.125 mm thick), a UV prism film formed by UV curing the UV-curable compositions of Examples 1-10 and Comparative Examples 1-5, and a flexible mold. The flexible mold is a 100 μm thick PET film with a prism microstructure formed by surface roll pressing. The surface of the PET film with the prism microstructure is coated with Dow SYL-OFF. TM 7786 Fluorosilicone Release Agent. The composite film is prepared as follows: The UV-curable compositions prepared in Examples 1-10 and Comparative Examples 1-5 are coated onto optical-grade polyester film A4360 with a coating weight of 10 g / m². 2 A composite film is prepared by laminating a soft mold with a PET film coated with a UV adhesive layer. The composite film is then cured under a medium-pressure mercury lamp at normal machine speed. The UV illuminance of the medium-pressure mercury lamp is 140 mW / cm².2 Exposure for 4 seconds, cumulative light energy 560 mJ / cm² 2 The sample to be tested is then cured.

[0109] Evaluation of the prism microstructure on the surface of the UV prism film: After the soft mold on the test sample is removed, a prism film with UV prism film / PET film is revealed. The prism microstructure on the surface of the UV prism film is observed using a multifunctional digital microscopic imaging system. If the prism microstructure on the surface of the UV prism film is relatively intact and without obvious damage, it is rated as good; otherwise, if the prism microstructure on the surface of the UV prism film is damaged, it is rated as poor. After the soft mold on the test sample is removed, a prism film with UV prism film / PET film is revealed. The refractive index of this prism film is measured using a refractometer according to ASTM D542-14, and the transmittance is measured according to GB / T 2410-2008 "Determination of transmittance and haze of transparent plastics".

[0110] Table 1: Test parameters of prism films with UV-curable adhesive / PET films prepared using the UV-curable compositions in Examples 1-10 and Comparative Examples 1-5

[0111]

[0112] Based on Examples 1-2 and Comparative Examples 1-2, and in conjunction with Table 1, it can be seen that the UV-curable composition prepared using the sulfur-containing polyurethane modified acrylate self-made in this invention can be completely cured at normal machine speed. The prism film composed of UV prism film / PET film has the advantages of high refractive index, high light transmittance, and high brightness. Moreover, the soft mold is easy to release and peel off. After the soft mold is released and peeled off, the prism microstructure on the surface of the UV prism film is relatively intact without obvious damage, which improves the yield of prism film. This solves the technical problems of the existing soft film molding process of prism film, which has the disadvantages of slow machine speed affecting production efficiency, prolonged UV exposure time aggravating UV aging of soft mold, shortening the recycling life of soft mold, and high production cost of prism film.

[0113] Based on Examples 1, 4-5, and Comparative Examples 3-4, and referring to Table 1, it can be seen that the sulfur-containing polyurethane-modified acrylate in the UV-curable composition affects the UV curing rate, with the content of sulfur-containing polyurethane-modified acrylate ranging from 3-12%. The prepared UV-curable composition can be completely cured at normal machine speed. After the soft mold is released and peeled off, the prism microstructure on the surface of the UV prism film is relatively intact without obvious damage.

[0114] As can be seen from Example 1 and Comparative Example 5, and Table 1, the UV reactive diluent composition system composed of o-phenylphenoxyethyl acrylate bisphenol A ethoxylated diacrylate and 2-phenoxyethyl acrylate effectively reduces the viscosity of the UV curing composition, ensuring that the prepared UV curing composition can be completely cured at normal machine speed, and the UV prism film has high refractive index, high light transmittance, and high brightness performance.

[0115] As can be seen from Examples 1 and 2-3 and Table 1, 2-phenylthioethanol acrylate and / or ethyl 4-mercaptocinnamate are used as UV reactive diluents to form a UV reactive diluent composition system, which can effectively reduce the viscosity of the UV curing composition. Under the premise of ensuring that the prepared UV curing composition can be completely cured at normal machine speed, it improves the refractive index, high light transmittance and luminance performance of the UV prism film.

[0116] Based on Examples 1 and 6-7 and Table 1, it can be seen that the UV-curable composition prepared using the sulfur-containing polyurethane modified acrylate in Preparation Example 2, under the premise that the prepared UV-curable composition can be completely cured at normal machine speed, exhibits advantages such as higher refractive index, higher light transmittance, and higher luminance in the prism film composed of UV prism adhesive film / PET film. It should be noted that during the experiment, in the prism films prepared with 0.2% fluorinated release agent, damage to the prism microstructure on the surface of the UV prism adhesive film was observed in all five prism films. In the prism films prepared with 0.3% fluorinated release agent, damage to the prism microstructure on the surface of the UV prism adhesive film was observed in one of the five prism films. The peel strength between the UV prism adhesive film and the soft mold is relatively high. The optimal amount of fluorinated release agent is 0.4% to ensure that the prism microstructure on the surface of the UV prism adhesive film remains relatively intact without significant damage after peeling from the soft mold.

[0117] Combining Examples 1 and 8 with Table 1, it can be seen that the self-made sulfur-containing polyol used in the sulfur-containing polyurethane modified acrylate contains -SS- disulfide bonds. The UV prism film prepared by the UV-curing composition in Example 8 exhibits better refractive index, transmittance, and luminance compared to the UV prism film prepared by the UV-curing composition in Example 1. Furthermore, the introduction of disulfide bonds endows the UV prism film with self-healing properties, improving its overall lifespan and durability. However, from a production cost perspective, the UV-curing composition in Example 8 is more expensive than that in Example 1. The UV-curing composition in Example 1 is more suitable for mass production, while the UV-curing composition in Example 8 is more suitable for meeting high-end customized customer needs.

[0118] Combining Examples 1 and 9 with Table 1, it can be seen that the UV prism film formed by the UV-curable composition prepared from sulfur-containing polyurethane modified acrylate produced by dimethyl phthalate (XDI) has better refractive index, transmittance, and luminance performance than the UV prism film formed by the UV-curable composition prepared from sulfur-containing polyurethane modified acrylate produced by toluene diisocyanate (TDI). The overall performance of the UV prism film can be improved by controlling the type of isocyanate.

[0119] Based on Examples 1 and 10 and Table 1, it can be seen that a highly reactive acrylate oligomer composition is formed by combining sulfur-containing polyurethane modified acrylate produced with tris(4-phenylisocyanate) TPTI with sulfur-containing polyurethane modified acrylate produced with toluene diisocyanate (TDI). This composition improves the refractive index, transmittance, and luminance performance of the formed UV prism film. The sulfur-containing polyurethane modified acrylate produced with tris(4-phenylisocyanate) TPTI exhibits higher reactivity, improving the photocuring efficiency of the UV-curable composition. It can achieve complete curing at high machine speeds (>16 m / min), enhancing the overall production efficiency of the prism film and optimizing the comprehensive performance of the UV prism film. From a production cost perspective, the production process of sulfur-containing polyurethane modified acrylate produced with tris(4-phenylisocyanate) TPTI in Preparation Example 10 has a higher cost, making it more suitable for meeting customers' high-end customized needs.

[0120] In summary, the UV curing composition of this invention has a high curing rate and can be completely cured at normal machine speed. The prism microstructure on the surface of the UV prism film after the soft mold is released is relatively intact without obvious damage. Furthermore, the UV prism film has the advantages of high refractive index, high brightness performance, and high light transmittance.

[0121] It should be noted that this specific embodiment is merely an explanation of the technical solution of the present invention and is not intended to limit the present invention. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but as long as they are within the scope of the claims of the present invention, they are protected by patent law.

Claims

1. A UV-curable composition for a ribbed prism film, characterized in that: The UV-curable composition comprises a highly reactive acrylate oligomer composition, a UV reactive diluent composition, a photoinitiator composition, and a non-silicone release agent; the UV reactive diluent composition accounts for 75-92 wt% of the UV-curable composition; the photoinitiator composition accounts for 2-6 wt% of the UV-curable composition; the non-silicone release agent accounts for 0.3-1 wt% of the UV-curable composition; the highly reactive acrylate oligomer composition accounts for 3-12 wt% of the UV-curable composition; and the highly reactive acrylate oligomer composition contains at least sulfur-containing... The polyurethane-modified acrylate contains sulfur in its main chain and / or has thiol-containing side chains grafted onto its main chain; the UV reactive diluent composition includes a monofunctional UV reactive diluent and a bifunctional UV reactive diluent; the monofunctional UV reactive diluent is at least one of o-phenylphenoxyethyl acrylate, 2-phenoxyethyl methacrylate, 2-phenoxyethyl acrylate, 2-phenylthioethanol acrylate, and ethyl 4-mercaptocinnamate; the bifunctional UV reactive diluent... The acrylate is at least one of bisphenol A glycerol dimethacrylate, bisphenol A ethoxylated diacrylate, and bisphenol A diallyl ether; the sulfur-containing polyurethane modified acrylate is made from isocyanate, polyol, hydroxy acrylate, polymerization inhibitor, catalyst, and organic solvent; the molar ratio of the -NCO functional group in the isocyanate to the hydroxyl group in the polyol is (1.3-2.0):1; the polyol main chain contains sulfur and / or the polyol main chain is grafted with mercapto-containing side chains; the hydroxy acrylate is hydroxyethyl acrylate and / or hydroxypropyl acrylate; the polymerization inhibitor is p-phenylene oxide. Diphenol and / or p-hydroxyanisole; the catalyst is an organotin catalyst or a titanate catalyst; the organotin catalyst is at least one of dibutyltin dilaurate and stannous octoate; the titanate catalyst is at least one of tetrabutyl titanate and tetraisopropyl titanate; the organic solvent is at least one of toluene, acetone, ethyl acetate, N,N-dimethylformamide, methyl ethyl ketone, and dimethyl carbonate; the isocyanate is one or more combinations of toluene diisocyanate, phenyl diisocyanate, and tris(4-phenylisocyanate) thiophosphate.

2. The UV-curable composition for a ribbed prism film according to claim 1, characterized in that: The polyol includes sulfur-containing polyols, which are made from phthalic acid, sulfur-containing diols, and small molecule diols; the phthalic acid is one or more combinations of biphenyl acid, terephthalic acid, phthalic acid, isophthalic acid, 2,3-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 1,4-naphthalenedicarboxylic acid, and 2,7-naphthalenedicarboxylic acid; the small molecule diol is one or more combinations of ethylene glycol, 1,3-propanediol, 1,2-propanediol, dipropylene glycol, trimerized 1,2-propanediol, 1,4-butanediol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, 1,6-hexanediol, phthalic acid, terephthalic acid, and isophthalic acid.

3. The UV-curable composition for a ribbed prism film according to claim 2, characterized in that: The sulfur-containing diol is one or a combination of 2,2-thiodiethanol, 2,2'-dithiodiethanol, and 3,3'-thiodipropanol.

4. The UV-curable composition for a ribbed prism film according to claim 1, characterized in that: The polyol includes sulfur-containing polyols, which are prepared from polyether glycols with a molecular weight of 300-1000 and mercapto-containing diacids; the mercapto-containing diacids are mercaptosuccinic acid and / or dimercaptosuccinic acid; the polyether glycols with a molecular weight of 300-1000 are one or more combinations of polyethylene glycol, polypropylene glycol, polytetrahydrofuran glycol, and branched polytetrahydrofuran glycol.

5. The UV-curable composition for a ribbed prism film according to claim 1, characterized in that: The preparation method of the sulfur-containing polyurethane modified acrylate is as follows: S1. Preparation of polyols; S2. The polyol is placed under vacuum at 110-125℃ for 1-2 hours to dehydrate. The temperature is then adjusted to 60-75℃. The dehydrated polyol is mixed with a precisely measured amount of isocyanate, organotin catalyst, and organic solvent. The reaction is maintained at 60-75℃ until the -NCO content in the system reaches the theoretical value, thus obtaining an isocyanate-terminated polyurethane prepolymer. S3. Add polymerization inhibitor and titanate catalyst to isocyanate-terminated polyurethane prepolymer, mix evenly, and then add hydroxy acrylate. Maintain the temperature at 60-75℃ for esterification and termination reaction for 30-90 minutes. Detect the -NCO content of the product in the reactor and find it to be 0. Then remove the organic solvent by vacuum distillation to obtain sulfur-containing polyurethane modified acrylate.

6. The UV-curable composition for a ribbed prism film according to claim 1, characterized in that: The photoinitiator composition is at least one of photoinitiator 2959, photoinitiator 184, photoinitiator TPO, photoinitiator 1173, and photoinitiator DETX; the non-silicone release agent is a fluorinated release agent.

7. A method for preparing a UV-curable composition for a ribbed prism film according to any one of claims 1-6, characterized in that: Includes the following steps: First, a highly reactive acrylate oligomer composition is prepared; Then, in a light-protected environment, the highly active acrylate oligomer composition, UV active diluent composition, and non-silicone release agent are mixed evenly with accurate measurements. Finally, under nitrogen protection, the photoinitiator composition is added, mixed evenly, discharged, and vacuum-packed to obtain the UV-curable composition for the prism film with horizontal stripe structure.

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