Photocurable composition, optical film, preparation method thereof and optical product

Abstract

The present invention provides a photocurable composition, an optical film, a preparation method thereof and an optical product. The photocurable composition includes a monomer, a cationic photoinitiator, a photosensitive resin and an antioxidant. The monomer is an oxetane monomer compound, and the structural formula of the oxetane monomer compound is wherein, R1 is selected from any one of substituted or unsubstituted alkyl groups having 1 to 5 carbon atoms, and R2 is selected from a substituted or unsubstituted straight-chain alkyl group having 1 to 40 substituted or unsubstituted straight-chain alkyl group having 3 to 40 substituted or unsubstituted branched-chain alkyl group having 3 to 30 substituted or unsubstituted aryl group having 6 to 10 substituted or unsubstituted heteroaryl group having 3 to One of them is substituted. Applying the photocurable composition containing the oxetane compound to the production of the optical film has advantages such as easy demolding and high yield.

Description

Technical Field

[0001] The present invention relates to the technical field of photocurable materials, and in particular, to a photocurable composition, an optical film, a preparation method thereof, and an optical product. Background Art

[0002] With the rapid development of display technologies such as liquid crystal display devices, for the optical films used therein, there can be mentioned prismatic sheets used in the backlights of liquid crystal display devices, etc., biconvex lenses used in stereoscopic photos, projection screens, etc., Fresnel lens sheets used in condenser lenses of overhead projectors, etc., diffraction gratings used in color filters, etc., and shaped films for lighting used in game machines, toys, household appliances, etc. Such optical films are also referred to as shaped films, and generally include a substrate and a shaped layer laminated on the substrate. By transferring a fine shape to the shaped layer using a mold or the like, desired optical properties can be imparted.

[0003] Traditional optical film manufacturing processes are mostly obtained by optical grinding or precision cutting with a diamond tool, which not only has high production difficulty, low yield, time-consuming and laborious, but also high cost and is easily damaged. Therefore, optical industry players have developed processing technologies for molding optics to produce resins to meet the huge market demand. For example, in the current production of lenses, the baking time for thermosetting resin lenses (such as the product name CR-39) is up to 20 hours, while for photocurable resin lenses, the curing speed is much faster during production, and it can be completed in just a few seconds to ten minutes, greatly improving the production efficiency of resin lenses. Since photocuring is completed in an extremely short time (a few seconds to ten minutes), photocuring polymerization is an exothermic reaction, and the reaction heat accumulates in the lens. Due to different thicknesses, the thermal expansion degrees of the lenses that enhance and amplify (myopia lenses) or reduce (presbyopia lenses) the optical effects are different. The greater the thickness (the edge part of myopia lenses or the central part of presbyopia lenses), the greater the expansion degree; conversely, the expansion degree of the thinner part of the lens is much lower. If the expansion degree difference is too large, before the curing is completed, the part with a larger expansion degree will push open the mold, causing the thinner part of the lens to prematurely separate from the mold, resulting in its deformation or even fragmentation. Summary of the Invention

[0004] The main object of the present invention is to provide a photocurable composition, an optical film, a preparation method thereof, and an optical product to solve the problems of low yield, easy deformation, and peeling of optical films in the prior art.

[0005] To achieve the above object, according to one aspect of the present invention, there is provided a photocurable composition, which includes a monomer, a cationic photoinitiator, a photosensitive resin, and an antioxidant. The monomer is an oxetane monomer compound, and the structural formula of the oxetane monomer compound is wherein, R1 is selected from any one of substituted or unsubstituted alkyl groups having 1 to 5 carbon atoms, and R2 is selected from C1 to C40 A substituted or unsubstituted straight-chain alkyl group, C3-C 40 Any one of a substituted or unsubstituted branched-chain alkyl group, and carbon or hydrogen in the straight-chain alkyl group and the branched-chain alkyl group may be substituted by one or more hydroxyl groups, ether bonds, ester groups, -S(O)2-, C6-C 30 A substituted or unsubstituted aryl group, C3-C 10 A substituted or unsubstituted heteroaryl group or Substituted, and at least one carbon or hydrogen in the straight-chain alkyl group and the branched-chain alkyl group is substituted by a substituted or unsubstituted aryl group of C6-C 30 A substituted or unsubstituted aryl group, C3-C 10 Substituted by one of a substituted or unsubstituted heteroaryl group of C3-C

[0006] Furthermore, R1 is an ethyl group, and R2 is selected from C1-C 10 A substituted or unsubstituted straight-chain alkyl group, C3-C 10 Any one of a substituted or unsubstituted branched-chain alkyl group.

[0007] Furthermore, at least one carbon or hydrogen in the straight-chain alkyl group and the branched-chain alkyl group is substituted by one of a substituted or unsubstituted aryl group of C6-C 25 Substituted by one of a substituted or unsubstituted heteroaryl group of C3-C5, preferably at least one carbon or hydrogen in the straight-chain alkyl group and the branched-chain alkyl group is substituted by one of a substituted or unsubstituted phenyl group, a substituted or unsubstituted biphenyl group, and a substituted or unsubstituted 9,9-diphenylfluorenyl group. Further preferably, at least one carbon or hydrogen in the branched-chain alkyl group is substituted by one of a phenyl group, a tolyl group, a biphenyl group, and a 9,9-diphenylfluorenyl group.

[0008] Furthermore, the above oxetane monomer compound is selected from

[0009] Any one or more of them. Preferably, the viscosity of the oxetane monomer compound is 8-3000 cps, and preferably the refractive index of the oxetane monomer compound is ≥1.499.

[0010] Furthermore, the above antioxidant is a phenolic antioxidant. Preferably, the phenolic antioxidant is selected from any one or more of butylated hydroxyanisole, dibutylhydroxytoluene, propyl gallate, tert-butylhydroquinone, tea polyphenols, and 2,4-dimethyl-6-styrenylphenol.

[0011] Furthermore, the above photocurable composition comprises 1-99 parts by weight of a monomer, 0.1-10 parts by weight of a cationic photoinitiator, 1-99 parts by weight of a photosensitive resin, and 1-30 parts by weight of an antioxidant.

[0012] Furthermore, the above-mentioned photocurable composition further comprises 0.1 to 100 parts by weight of an auxiliary agent, and preferably the auxiliary agent is selected from any one or more of a stabilizer, a release agent, a wetting agent, a dispersant, a slip agent, a rheology modifier, an antifoaming agent, and a reinforcing agent.

[0013] Furthermore, the above-mentioned cationic photoinitiator is selected from any one or more of iodonium salts or sulfonium salts.

[0014] Furthermore, the above-mentioned photosensitive resin is selected from any one or more of oxetane resins, epoxy resins, vinyl ether resins, and amino resin compounds. Preferably, the oxetane resin is selected from any one or more of bisphenol A type oxetane resin, bisphenol F type oxetane resin, biphenyl type oxetane resin, phenol novolak type oxetane resin, cresol novolak type oxetane resin, bisphenol A novolak type oxetane resin, aliphatic polyoxetane compound, cycloaliphatic oxetane resin, rosin resin modified oxetane resin, oil-free alkyd resin modified oxetane resin, oil alkyd resin modified oxetane resin, phenolic resin modified oxetane resin, amino resin modified oxetane resin, acrylic resin modified oxetane resin, nitrocellulose modified oxetane resin, and silicone resin modified oxetane resin; preferably, the epoxy resin is selected from any one or more of bisphenol A type epoxy resin, bisphenol F type epoxy resin, glycidyl ether type epoxy resin, glycidyl ester type epoxy resin, biphenyl type epoxy resin, phenol novolak type epoxy resin, cresol novolak type epoxy resin, bisphenol A novolak type epoxy resin, aliphatic polyglycidyl ether compound, cycloaliphatic epoxy resin, and epoxy compound having a siloxane bonding site, and the epoxy equivalent of the epoxy resin is greater than 200.

[0015] According to another aspect of the present invention, there is provided an optical film prepared from the above-mentioned photocurable composition.

[0016] According to still another aspect of the present invention, there is provided a method for preparing the above-mentioned optical film, the preparation method comprising: Step S1, mixing the monomer and the cationic photoinitiator in the above-mentioned photocurable composition under ultraviolet light irradiation to form a first mixed solution; Step S2, mixing the first mixed solution, the photosensitive resin, and the antioxidant at a temperature of 0 to 20 °C to form a second mixed solution; Step S3, defoaming the second mixed solution to obtain a defoamed mixed solution; and Step S4, at a temperature of 0 to 25 °C, putting the defoamed mixed solution into a molding die for molding to obtain the optical film.

[0017] According to still another aspect of the present invention, there is provided an optical product, the optical product comprising an optical film, and the optical film is the above-mentioned optical film.

[0018] Further, the above optical products are prism lenses, convex lenses, Fresnel lenses, and diffraction gratings.

[0019] Applying the technical solution of the present invention, since oxetane compounds have advantages such as low viscosity and small curing shrinkage, adding oxetane monomers to the photocurable composition can significantly reduce the viscosity and reaction time of the photocurable composition, and at the same time can also improve the control of the flexibility of the polymer. Through painstaking research, the inventor surprisingly found that by using the light-curing separation technology and utilizing the delayed curing characteristics of oxetane, the defects of incomplete release of stress in the photocuring technology, uneven thickness of the lens, and low yield of the optical film are overcome. Therefore, even if the oxetane compound having an aryl or heteroaryl structure is used alone, there is no need to worry about problems such as early demolding, low yield, and deformation caused by the inability to release the stress of rapid curing of the optical element, thereby reducing the requirements for the production environment (thermal curing site) and production technology (light source equipment, thermal curing equipment), and further reducing the production cost of the photocurable resin lens. In particular, the oxetane compound of the present application contains an aryl or heteroaryl rigid group and has a relatively high refractive index. Using the optical film containing the oxetane compound in the production of optical products can greatly reduce the thickness of the lens in the optical product, obtain a lightweight optical product, and overcome problems such as high production energy consumption and poor production environment. Detailed Embodiments

[0020] It should be noted that, without conflict, the embodiments in the present application and the features in the embodiments can be combined with each other. The present invention will be described in detail below with reference to the embodiments.

[0021] As analyzed in the background art, there are problems of low yield, easy deformation, and shedding of the optical film in the prior art. To solve this problem, the present invention provides a photocurable composition, an optical film, a preparation method thereof, and an optical product.

[0022] In a typical embodiment of the present application, a photocurable composition is provided. The photocurable composition includes a monomer, a cationic photoinitiator, a photosensitive resin, and an antioxidant. The monomer is an oxetane monomer compound, and the structural formula of the oxetane monomer compound is wherein, R1 is selected from any one of substituted or unsubstituted alkyl groups having 1 to 5 carbon atoms, and R2 is selected from any one of substituted or unsubstituted straight-chain alkyl groups having 1 to C 40 substituted or unsubstituted branched-chain alkyl groups having 3 to C 40 and the carbon or hydrogen in the straight-chain alkyl group and the branched-chain alkyl group can be replaced by one or more hydroxyl groups, ether bonds, ester groups, -S(O)2-, substituted or unsubstituted aryl groups having 6 to C 30 substituted or unsubstituted heteroaryl groups having 3 to C 10 or substituted, and at least one carbon or hydrogen in the linear alkyl group or branched alkyl group is replaced by one of a substituted or unsubstituted aryl group having 6 to 30 substituted or unsubstituted aryl groups having 3 to 10 substituted or unsubstituted heteroaryl groups having 3 to

[0023] Since oxetane compounds have advantages such as low viscosity and small curing shrinkage, adding oxetane monomers to the photocurable composition can significantly reduce the viscosity and reaction time of the photocurable composition, and at the same time can also improve the control of the flexibility of the polymer. Through painstaking research, the inventors of the present invention surprisingly found that by using the photo-curing separation technology and utilizing the delayed curing characteristics of oxetane, the defects of incomplete release of stress in the photocuring technology, uneven thickness of the lens, and low yield of the optical film are overcome. Therefore, even if the oxetane compound having an aryl or heteroaryl structure is used alone, there is no need to worry about problems such as early demolding, low yield, and deformation caused by the inability to release the stress of rapid curing of the optical element, thereby reducing the requirements for the production environment (thermal curing site) and production technology (light source equipment, thermal curing equipment), and further reducing the production cost of the photocurable resin lens. In particular, the oxetane compound of the present application contains an aryl or heteroaryl rigid group and has a high refractive index. Using the optical film containing the oxetane compound in the production of optical products can greatly reduce the thickness of the lens in the optical product, obtain a light-weight optical product, and overcome problems such as high production energy consumption and poor production environment.

[0024] To improve the oxetane compound, it is preferred that R1 is an ethyl group, and R2 is selected from a substituted or unsubstituted linear alkyl group having 1 to 10 substituted or unsubstituted linear alkyl groups having 3 to 10 substituted or unsubstituted branched alkyl groups having 3 to

[0025] To further improve the refractive index of the oxetane compound and thus make a thinner lens, it is preferred that at least one carbon or hydrogen in the linear alkyl group or branched alkyl group is replaced by one of a substituted or unsubstituted aryl group having 6 to 25 substituted or unsubstituted aryl groups having 3 to 5, preferably at least one carbon or hydrogen in the linear alkyl group or branched alkyl group is replaced by one of a substituted or unsubstituted phenyl group, a substituted or unsubstituted biphenyl group, and a substituted or unsubstituted 9,9-diphenylfluorenyl group. Further preferably, at least one carbon or hydrogen in the branched alkyl group is replaced by one of a phenyl group, a tolyl group, a biphenyl group, and a 9,9-diphenylfluorenyl group.

[0026] In one embodiment of the present application, the above oxetane monomer compound is selected from

[0027] Any one or more of them. Preferably, the viscosity of the oxetane monomer compound is 8 to 3000 cps, and the refractive index of the oxetane monomer compound is ≥1.499.

[0028] The above-mentioned oxetane monomer compound can more fully exert the improvement effect on the properties such as the flexibility of the polymer, thereby improving the yield of the optical film. Controlling the viscosity of the oxetane monomer compound within the above range is more conducive to controlling the viscosity of the photocurable composition, thereby facilitating the production of the optical film. Controlling the refractive index of the oxetane monomer compound is beneficial to obtaining an optical film that meets the optical performance requirements.

[0029] To improve the antioxidant property of the photocurable composition and thus obtain an optical film with excellent antioxidant property, preferably, the above antioxidant is a phenolic antioxidant, and preferably, the phenolic antioxidant is selected from any one or more of butylated hydroxyanisole, dibutylhydroxytoluene, propyl gallate, tert-butylhydroquinone, tea polyphenols, 2,4-dimethyl-6-styrenylphenol.

[0030] In one embodiment of the present application, the above photocurable composition comprises 1 to 99 parts by weight of monomer, 0.1 to 10 parts by weight of cationic photoinitiator, 1 to 99 parts by weight of photosensitive resin, and 1 to 30 parts by weight of antioxidant.

[0031] Controlling the content of each component in the above photocurable composition within the above range is beneficial to improving the synergistic effect among the components, thereby obtaining a photocurable composition with better performance.

[0032] To further obtain optical films with diverse properties, preferably, the above photocurable composition further comprises 0.1 to 100 parts by weight of additives, and preferably, the additives are selected from any one or more of stabilizers, mold release agents, wetting agents, dispersants, slip agents, rheology modifiers, defoamers, reinforcing agents.

[0033] As an important component in cationic photocurable coatings, the cationic photoinitiator will photolyze to generate active groups after being irradiated with light and can maintain its activity for a long time after being mixed with the above monomer. To ensure that the photoinitiator maintains its activity for a long time after photolysis, preferably, the above cationic photoinitiator is selected from any one or more of iodonium salts or sulfonium salts. By way of example, the cationic parts of the above iodonium salt and sulfonium salt photoinitiators can be exemplified by the following structures:

[0034]

[0035]

[0036]

[0037] As an example, the anionic parts of the above-mentioned iodonium salt and sulfonium salt photoinitiators may include: Cl - 、Br - 、PF6 - 、SbF6 - 、AsF6 - 、BF4 - 、C4F9SO3 - 、B(C6H5)4 - 、C8F 17 SO3 - 、CF3SO3 - 、Al[OC(CF3)3]4 - 、(CF3CF2)2PF4 - 、(CF3CF2)3PF3 - 、[(CF3)2CF2]2PF4 - 、[(CF3)2CF2]3PF3 - 、[(CF3)2CFCF2]2PF4 - 、(CF3)2CFCF2]3PF3 - 。

[0038] Commercially available cationic photoinitiators with similar structures can also be used in component (C) of the present invention. Examples include (but are not limited to): PAG20001, PAG20001s, PAG20002, PAG20002s, PAG30201, PAG30101, etc. produced by Tronly Company, and Irgacure250 produced by BASF Company.

[0039] Resin-based composites have the advantages of light weight, high strength, and designable mechanical properties. To utilize the above advantages, it is preferred that the photosensitive resin is selected from any one or more of oxetane resins, epoxy resins, vinyl ether resins, and amino resin compounds. Preferably, the oxetane resin is selected from any one or more of bisphenol A type oxetane resin, bisphenol F type oxetane resin, biphenyl type oxetane resin, phenol novolac type oxetane resin, cresol novolac type oxetane resin, bisphenol A novolac type oxetane resin, aliphatic polyoxetane compounds, cycloaliphatic oxetane resin, rosin resin modified oxetane resin, non-oil alkyd resin modified oxetane resin, oil alkyd resin modified oxetane resin, phenolic resin modified oxetane resin, amino resin modified oxetane resin, acrylic resin modified oxetane resin, nitrocellulose modified oxetane resin, and silicone resin modified oxetane resin; preferably, the epoxy resin is selected from any one or more of bisphenol A type epoxy resin, bisphenol F type epoxy resin, glycidyl ether type epoxy resin, glycidyl ester type epoxy resin, biphenyl type epoxy resin, phenol novolac type epoxy resin, cresol novolac type epoxy resin, bisphenol A novolac type epoxy resin, aliphatic polyglycidyl ether compounds, cycloaliphatic epoxy resin, and epoxy compounds having a siloxane bonding site, and the epoxy equivalent of the epoxy resin is greater than 200.

[0040] In another typical embodiment of the present application, an optical film is provided, which is prepared from the aforementioned photocurable composition.

[0041] Due to the advantages of low viscosity and small curing shrinkage of oxetane compounds in the above-mentioned photocurable composition, adding oxetane monomers to the photocurable composition can significantly reduce the viscosity and reaction time of the photocurable composition, and at the same time improve the control of the flexibility of the polymer. Through painstaking research, the inventors surprisingly found that by using the light-curing separation technology and utilizing the delayed curing characteristics of oxetane, the defects of incomplete release of stress in the photocuring technology, uneven thickness of the lens, and low yield of the optical film are overcome. Therefore, even if the oxetane compound having an aryl or heteroaryl structure is used alone, there is no need to worry about problems such as early demolding, low yield, and deformation caused by the inability to release the stress of rapid curing of the optical element, thereby reducing the requirements for the production environment (thermal curing site) and production technology (light source equipment, thermal curing equipment), and further reducing the production cost of the photocurable resin lens. In particular, the oxetane compound of the present application contains an aryl or heteroaryl rigid group and has a high refractive index. Using the optical film containing the oxetane compound in the production of optical products can greatly reduce the thickness of the optical film (such as the lens) in the optical product, obtain a lightweight optical product, and overcome problems such as high production energy consumption and poor production environment.

[0042] The photocurable composition containing the oxetane compound is applied to the production of an optical film, and an optical film with excellent optical properties is obtained.

[0043] In another typical embodiment of the present application, a method for preparing the aforementioned optical film is provided. The preparation method includes: Step S1, mixing the monomer and cationic photoinitiator in the aforementioned photocurable composition under ultraviolet light irradiation to form a first mixed solution; Step S2, mixing the first mixed solution, the photosensitive resin, and the antioxidant at a temperature of 0 to 20 °C to form a second mixed solution; Step S3, defoaming the second mixed solution to obtain a defoamed mixed solution; and Step S4, at a temperature of 0 to 25 °C, putting the defoamed mixed solution into a molding mold for molding to obtain an optical film.

[0044] After the above-mentioned monomer and photosensitive resin are polymerized under the action of the cationic photoinitiator, a second mixed solution is obtained. Defoaming and then molding the second mixed solution is beneficial to obtaining an optical film with better compactness, which is more conducive to obtaining an optical product with better uniformity, and further conducive to exerting its excellent optical properties. To improve the molding efficiency, in the present application, it is preferably set that the temperature of the molding mold is 25 to 100 °C after putting the defoamed mixed solution into the molding mold, and after keeping the temperature constant for 1 to 5 minutes, the molded optical film is obtained. Of course, to obtain a more delicate optical film, it is preferably to demold, edge grind, clean and dry the molded optical film to obtain the final optical film.

[0045] In another typical embodiment of the present application, an optical product is provided. The optical product includes an optical film, and the optical film is the aforementioned optical film.

[0046] Applying the optical film of the present application to the above-mentioned optical product can further exert the excellent properties of the optical film of the present application, and obtain an optical product with excellent optical properties.

[0047] In one embodiment of the present application, the above-mentioned optical product is a prism sheet, a convex lens sheet, a Fresnel lens sheet, a diffraction grating.

[0048] Applying the above-mentioned optical film of the present application to the above-mentioned types of optical products can more fully exert the optical properties of the optical film of the present application. For example, using the optical film of the present application in a prism sheet used in the backlight of a liquid crystal display device, a biconvex lens sheet used in a stereoscopic photo and a projection screen, a Fresnel lens sheet used in a condenser lens of a projector, a diffraction grating used in a color filter, an optical sheet used in a game machine, a toy, a household appliance, etc., or as an optical sheet used in a vehicle-mounted display.

[0049] Hereinafter, the beneficial effects of the present application will be described in conjunction with specific examples and comparative examples.

[0050] Preparation of Optical Film

[0051] Taking Example 1 as an illustration, the preparation of the optical film is described as follows.

[0052] Example 1

[0053] At room temperature, A-1 and B-1 are mixed evenly and stirred under a mercury lamp source (5000 mJ / cm 2 , 3 min) to form a first mixed solution. Then, at 0 °C, components C-1, D-1, and E-1 are added to the first mixed solution and stirred evenly to form a second mixed solution. The second mixed solution is subjected to ultrasonic degassing for 15 min to obtain a degassed mixed solution. Subsequently, at 25 °C, the degassed mixed solution is filled into a lens molding mold, the air in the mold is removed, and the mold is sealed with a rubber ring or tape. The mold is placed in a constant-temperature device, the temperature of the mold is raised to 10 °C, held at a constant temperature for 1 min, then the temperature is raised to 25 °C for a second time and held at a constant temperature for 1 min; the temperature is raised to 35 °C for a third time, held at a constant temperature for 1 min, and then the mold is taken out. After demolding, edging, cleaning, and drying, the optical film is obtained. The quality of the product after the optical film is peeled off is observed, and performance tests are carried out.

[0054] By changing the types and contents of each component (the unit of each component content is parts by weight), the following Examples 2 to 10 are set as shown in Table 1.

[0055] Table 1

[0056]

[0057]

[0058] Among them, A-1: Refractive index is 1.4999, viscosity is 8.1 cps;

[0059] A-2: Refractive index is 1.5011, viscosity is 30.6 cps;

[0060] A-3: Refractive index is 1.5069, viscosity is 240 cps;

[0061] A-4: Refractive index is 1.5048, viscosity is 53.2 cps;

[0062] A-5: Refractive index is 1.5325, viscosity is 503 cps;

[0063] A-6: Refractive index is 1.5109, viscosity is 276 cps;

[0064] B-1: Tris(3-fluoro-4-methylphenyl)sulfonium hexafluorophosphate; B-2: 4,4'-Dimethyliodonium tetrakis(pentafluorophenyl)borate;

[0065] C-1: Oxetane-modified bisphenol F epoxy resin; C-2: Oxetane-modified bisphenol S epoxy resin;

[0066] D-1: Tea polyphenols; D-2: 2,4-Dimethyl-6-styrylphenol;

[0067] E-1: Acryloyl-containing polyether-modified polydimethylsiloxane (release agent).

[0068] Example 11

[0069] The difference between Example 11 and Example 1 is that the cationic photoinitiator is B-2, and an optical film is finally obtained.

[0070] Example 12

[0071] The difference between Example 12 and Example 1 is that the photosensitive resin is C-2, and an optical film is finally obtained.

[0072] Example 13

[0073] The difference between Example 13 and Example 1 is that the antioxidant is D-2, and an optical film is finally obtained.

[0074] Example 14

[0075] The difference between Example 14 and Example 6 is that A-5 is 99 parts by weight, B-1 is 10 parts by weight, C-1 is 99 parts by weight, D-2 is 30 parts by weight, and E-1 is 1 part by weight, and an optical film is finally obtained.

[0076] Example 15

[0077] The difference between Example 15 and Example 6 is that A-5 is 1 part by weight, B-1 is 1 part by weight, C-1 is 1 part by weight, D-2 is 1 part by weight, and E-1 is 0.1 part by weight, and an optical film is finally obtained.

[0078] Example 16

[0079] Example 16 is different from Example 1 in that component C-1, D-1, and E-1 are added to the first mixed solution at 20°C and stirred evenly to form a second mixed solution. At 0°C, the degassed mixed solution is filled into a lens molding mold, the air in the mold is removed, and the mold is sealed with a rubber ring or tape. The mold is placed in a constant temperature device, the temperature of the mold is raised to 10°C, after standing for 1 min at a constant temperature, the temperature is raised to 25°C for the second time, and then held at a constant temperature for 1 min; the temperature is raised to 35°C for the third time, after standing for 1 min at a constant temperature, the mold is taken out, demolded, edged, cleaned and dried, and finally an optical film is obtained. Observe the quality of the product after the optical film is peeled off and perform performance tests.

[0080] Comparative Example 1

[0081] Comparative Example 1 is different from Example 1 in that the oxetane monomer compound is Finally, an optical film is obtained.

[0082] Comparative Example 2

[0083] Comparative Example 2 is different from Example 1 in that 3,4-epoxycyclohexylmethyl 3,4-epoxycyclohexanecarboxylate and B-1 are mixed evenly and stirred under a mercury lamp source (5000 mJ / cm 2 , 3 min), partial curing occurs, and subsequent evaluation and testing operations cannot be carried out.

[0084] Performance Evaluation

[0085] (1) UV formability

[0086] The UV formability of the optical films of Examples 1 to 16, Comparative Example 1, and Comparative Example 2 was evaluated with the naked eye. The judgment criteria are as follows: ○: completely cured; ×: incompletely cured.

[0087] (2) Release force (demoldability) of the optical film

[0088] The demoldability of the optical films of Examples 1 to 16, Comparative Example 1, and Comparative Example 2 was evaluated with the naked eye. The judgment criteria are as follows: ○: can be completely demolded; ×: incompletely demolded or the optical film itself is damaged.

[0089] (3) Stress marks

[0090] The transparency of the optical films of Examples 1 to 16, Comparative Example 1, and Comparative Example 2 was evaluated with the naked eye after being placed on a diffusion film respectively. The judgment criteria are as follows: ○: no stress marks; ×: there are stress marks.

[0091] (4) Transparency

[0092] The transparency of the optical films of Examples 1 to 16, Comparative Example 1, and Comparative Example 2 was respectively tested using an ultraviolet-visible luminance meter, and the judgment criteria were as follows: ○: Transmittance ≥ 92%; ×: Transmittance < 92%.

[0093] (5) Yellowing property

[0094] The yellowing properties of the optical films of Examples 1 to 16, Comparative Example 1, and Comparative Example 2 were evaluated by the naked eye, and the judgment criteria were as follows: ○: No yellowing; ○+: Slightly yellowing.

[0095] (6) Refractive index and Abbe number

[0096] The refractive indices and Abbe numbers of the optical films of Examples 1 to 16, Comparative Example 1, and Comparative Example 2 were respectively tested using a multi-wavelength refractometer (SCHMIDT HAENSCH).

[0097] (7) Impact resistance

[0098] The impact resistances of the optical films of Examples 1 to 16, Comparative Example 1, and Comparative Example 2 were respectively tested with reference to the national standard GB / T5891-1986 Test Methods for Impact Resistant Eye Protectors: ○: The optical film was not damaged; ×: The optical film was fragmented or cracked.

[0099] The above test results are listed in Table 2.

[0100] Table 2

[0101]

[0102] From the above description, it can be seen that the above embodiments of the present invention achieve the following technical effects:

[0103] Since oxetane compounds have advantages such as low viscosity and small curing shrinkage, adding oxetane monomers to the photocurable composition can significantly reduce the viscosity and reaction time of the photocurable composition, and at the same time improve the control of the flexibility of the polymer. Through painstaking research, the inventors of the present invention surprisingly found that by using the photo-curing separation technology and utilizing the delayed curing characteristics of oxetane, the defects of the photocuring technology, such as incomplete release of stress, uneven thickness of the lens, and low yield of the optical film, were overcome. Therefore, even if the oxetane compound having an aryl or heteroaryl structure is used alone, there is no need to worry about problems such as early demolding, low yield, and deformation caused by the inability to release the stress of rapid curing of the optical element, thereby reducing the requirements for the production environment (thermal curing site) and production technology (light source equipment, thermal curing equipment), and further reducing the production cost of the photocurable resin lens. In particular, the oxetane compound of the present application contains an aryl or heteroaryl rigid group and has a relatively high refractive index. Using the optical film containing the oxetane compound in the production of optical products can greatly reduce the thickness of the lens in the optical product, obtain a lightweight optical product, and overcome problems such as high production energy consumption and poor production environment.

[0104] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for preparing an optical film, characterized in that, The preparation method includes: Step S1, mixing the monomer and cationic photoinitiator in the photocurable composition under ultraviolet light irradiation to form a first mixed solution; Step S2, mixing the first mixed solution, photosensitive resin, and antioxidant at a temperature of 0 to 20 °C to form a second mixed solution; Step S3, degassing the second mixed solution to obtain a degassed mixed solution; and Step S4, at a temperature of 0 to 25 °C, putting the degassed mixed solution into a molding die for molding to obtain an optical film; Wherein, the photocurable composition includes 1 to 99 parts by weight of monomer, 0.1 to 10 parts by weight of cationic photoinitiator, 1 to 99 parts by weight of photosensitive resin, and 1 to 30 parts by weight of antioxidant; The monomer is an oxetane monomer compound; The oxetane monomer compound is selected from any one or more of; The viscosity of the oxetane monomer compound is 8 to 3000 cps, and the refractive index of the oxetane monomer compound is ≥1.

499.

2. The preparation method according to claim 1, characterized in that, The antioxidant is a phenolic antioxidant, and the phenolic antioxidant is selected from any one or more of butylated hydroxyanisole, dibutylhydroxytoluene, propyl gallate, tert-butylhydroquinone, tea polyphenols, 2,4-dimethyl-6-styrenylphenol.

3. The preparation method according to claim 1, wherein The photocurable composition further includes 0.1 to 100 parts by weight of an auxiliary agent, and the auxiliary agent is selected from any one or more of a stabilizer, a release agent, a wetting agent, a dispersant, a slip agent, a rheology modifier, an antifoaming agent, and a reinforcing agent.

4. The preparation method according to claim 1, characterized in that, The cationic photoinitiator is selected from any one or more of iodonium salts or sulfonium salts.

5. The preparation method according to claim 1, wherein, The photosensitive resin is selected from any one or more of oxetane resins, epoxy resins, vinyl ether resins, and amino resin compounds.

6. The preparation method according to claim 5, wherein The oxetane resin is selected from any one or more of bisphenol A type oxetane resin, bisphenol F type oxetane resin, biphenyl type oxetane resin, phenol novolak type oxetane resin, cresol novolak type oxetane resin, bisphenol A novolak type oxetane resin, aliphatic polyoxetane compound, cycloaliphatic oxetane resin, rosin resin modified oxetane resin, non-oil alkyd resin modified oxetane resin, oil alkyd resin modified oxetane resin, phenolic resin modified oxetane resin, amino resin modified oxetane resin, acrylic resin modified oxetane resin, nitrocellulose modified oxetane resin, and silicone resin modified oxetane resin.

7. The preparation method according to claim 5, characterized in that, The epoxy resin is selected from any one or more of bisphenol A type epoxy resin, bisphenol F type epoxy resin, glycidyl ether type epoxy resin, glycidyl ester type epoxy resin, biphenyl type epoxy resin, phenol novolak type epoxy resin, cresol novolak type epoxy resin, bisphenol A novolak type epoxy resin, aliphatic polyglycidyl ether compound, cycloaliphatic epoxy resin, and epoxy compound having a siloxane bonding site, and the epoxy equivalent of the epoxy resin is greater than 200.

8. An optical film, characterized in that, The optical film is prepared by the preparation method described in any one of claims 1 to 7.

9. An optical product, the optical product comprising an optical film, characterized in that, The optical film is the optical film described in claim 8.

10. The optical product according to claim 9, characterized in that, The optical products are prism lenses, convex lens sheets, Fresnel lens sheets, and diffraction gratings.

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