Non-film-forming matrix, photopolymer, film, preparation method and substrate

Abstract

The present application relates to the technical field of volume holographic display materials, and in particular to a non-film-forming matrix, a photopolymer, a film, a preparation method and a substrate. The preparation method for a photopolymer film comprises the steps of: in percentage by mass, weighing, in proportion, methyl methacrylate, a low-Tg acrylic monomer, a cross-linking acrylic monomer, a rigid side group monomer, a fluorine-containing or silicon-containing acrylic monomer and a free radical thermal initiator as a matrix, wherein in percentage by mass, the matrix comprises 40-85% of methyl methacrylate, 0-50% of the low-Tg acrylic monomer, 0-20% of the cross-linking acrylic monomer, 5-20% of the rigid side group monomer, 4-20% of the fluorine-containing or silicon-containing acrylic monomer, and 0.5-5% of the free radical thermal initiator; heating the matrix in a solvent 1 and refluxing for 1-8 hours to obtain a non-film-forming matrix; and weighing, in proportion, the non-film-forming substrate, a high-refractive-index monomer, a visible light capturing agent and a photoinitiator as a raw material I, wherein in percentage by mass, the raw material comprises 40-80% of the non-film-forming substrate, 10-45% of the high-refractive-index monomer, 0.01-5% of the visible light capturing agent, and 1-10% of the photoinitiator.

Description

Non-film-forming matrix, photopolymer, film, preparation method, and substrate Technical Field

[0001] The present application relates to the technical field of volume holographic display materials, in particular to a non-film-forming matrix and a photopolymer, a film, a preparation method, and a substrate. Background Art

[0002] Current AR waveguide technology is divided into three generations: the first generation array waveguides, the second generation surface relief grating waveguides, and the third generation volume holographic waveguides. The third generation volume holographic waveguides are realized using a thin photosensitive coating that is exposed through laser interference to form a volume holographic grating. The refractive index difference between the bright and dark stripes of the volume holographic grating is called refractive index modulation.

[0003] Materials commonly used to make volume holographic gratings include silver salts, dichromated gelatin, and photosensitive polymers. Photosensitive polymers offer advantages such as high sensitivity, high resolution, high diffraction efficiency, wide spectral response, simple processing, wide tolerance, and stable storage, making them ideal materials for recording volume holographic image information. Photosensitive polymers can be divided into three categories: photopolymerizable, photocrosslinkable, and photodegradable. Photopolymers are a type of photopolymerizable material. Technical issues

[0004] In current photopolymer production, unexposed photopolymer is coated on a protective film, dried, and then covered with a protective film. However, because existing photopolymers typically use polyvinyl acetate (EVA) or partially fluorinated polymers of EVA as a matrix to form the film, they adhere to the protective film after light curing, making it difficult to completely remove the protective film and transfer the printed image, significantly limiting the application of photopolymers. Technical Solutions

[0005] The present application provides a method for preparing a photopolymer film, comprising the steps of:

[0006] By weight percentage, methyl methacrylate, low Tg acrylic monomer, cross-linked acrylic monomer, rigid side group monomer, fluorine-containing or silicon-containing acrylic monomer and free radical thermal initiator are weighed in proportion to form a matrix; wherein, by weight percentage, methyl methacrylate is 40-85%, low Tg acrylic monomer is 0-50%, cross-linked acrylic monomer is 0-20%, rigid side group monomer is 5-20%, fluorine-containing or silicon-containing acrylic monomer is 4-20%, and free radical thermal initiator is 0.5-5%;

[0007] The matrix is ​​heated under reflux in solvent 1 for 1-8 hours to obtain a non-film-forming matrix;

[0008] Weigh a non-film-forming matrix, a high-refractive index monomer, a visible light harvester, and a photoinitiator in proportion to obtain the first raw material; wherein, by mass percentage, the non-film-forming matrix comprises 40-80%, the high-refractive index monomer comprises 10-45%, the visible light harvester comprises 0.01-5%, and the photoinitiator comprises 1-10%;

[0009] The raw material 1 is stirred and dissolved in the solvent 2 to obtain a photopolymer solution;

[0010] Making a volume holographic grating master with positioning marks;

[0011] coating a photopolymer solution on a protective film and drying the solution to form a photopolymer coating, and covering the photopolymer coating with a protective film to obtain a photopolymer intermediate;

[0012] replicating the volume holographic grating on the volume holographic grating master to a photopolymer intermediate to obtain a photopolymer film with the volume holographic grating;

[0013] UV irradiation and heating of photopolymer films.

[0014] The present application also discloses a photopolymer, which comprises, by mass percentage, 50-80% of a matrix and 20-50% of a complexing base; wherein the complexing base comprises:

[0015] High refractive index monomer 70-90%

[0016] Visible light capture agent 0.1-10%

[0017] Photoinitiator 9-20%;

[0018] Wherein, by mass percentage, the matrix comprises:

[0019] Methyl methacrylate 40-85%

[0020] Low Tg acrylic monomer 0-50%

[0021] Cross-linked acrylic acid monomer 0-20%

[0022] Rigid side group monomer 5-20%

[0023] Fluorine-containing or silicon-containing acrylic monomer 4-20%

[0024] Free radical thermal initiator 0.5-5%.

[0025] Optionally, the low Tg acrylic monomer is one or more of ethyl acrylate (EA), butyl acrylate (BA), isooctyl acrylate (2-EHA), lauryl acrylate, and dodecyl acrylate.

[0026] Optionally, the cross-linked acrylic monomer is one or more of hydroxyethyl acrylate (HEA), hydroxyethyl methacrylate (HEMA), acrylamide (AAM), hydroxymethyl acrylamide (NMA), diacetone acrylamide (DAAM), ethyl acetoacetate methacrylate (AAEM), glycidyl methacrylate (GMA), and dimethylaminoethyl methacrylate (DMAEMA); and / or

[0027] The rigid side group monomer is one or more of isobornyl methacrylate (IBOA), dicyclopentadiene and its derivatives, and adamantyl acrylates.

[0028] Optionally, the fluorine-containing acrylic monomer is one or more of trifluoroethyl acrylate (TFEA), trifluoroethyl methacrylate (TFEMA), hexafluorobutyl acrylate (HFBA), and dodecafluoroheptyl methacrylate (DFMA);

[0029] The silicon-containing acrylic monomer is one or more of methylvinylchlorosilane, vinyltrichlorosilane, and vinyltriethoxysilane (VTES).

[0030] Optionally, the free radical thermal initiator is one or more of azobisisobutyronitrile, azobisisoheptanenitrile and dimethyl azobisisobutyrate, hydrogen peroxide, ammonium persulfate, potassium persulfate, benzoyl peroxide, tert-butyl benzoyl peroxide, methyl ethyl ketone peroxide, dibenzoyl peroxide, N,N-dimethylaniline or dimethyl-β-thiophene propionate.

[0031] Optionally, the matrix comprises, by mass percentage:

[0032] Methyl methacrylate 69.4%

[0033] Butyl acrylate 6%

[0034] Hydroxyethyl methacrylate 0%

[0035] Isobornyl methacrylate 13.6%

[0036] Dodecafluoroheptyl methacrylate 10%

[0037] Benzoyl peroxide 0.7%

[0038] N,N-dimethyl-p-toluidine 0.7%.

[0039] The present application also discloses a non-film-forming matrix for photopolymer, which comprises, by mass percentage, 30-70% matrix and 30-70% solvent 1, wherein the matrix comprises:

[0040] Methyl methacrylate 40-85%

[0041] Low Tg acrylic monomer 0-50%

[0042] Cross-linked acrylic acid monomer 0-20%

[0043] Rigid side group monomer 5-20%

[0044] Fluorine-containing or silicon-containing acrylic monomer 4-20%

[0045] Free radical thermal initiator 0.5-5%.

[0046] The present application also discloses a photopolymer film, comprising the above-mentioned photopolymer and two layers of protective films, wherein the two layers of protective films respectively cover two sides of the photopolymer.

[0047] The present application also discloses a photopolymer substrate, comprising a substrate and the photopolymer as described above, wherein the photopolymer is cured on the substrate and the photopolymer has a volume holographic grating. Beneficial effects

[0048] Compared with the prior art, the beneficial effects of the photopolymer provided in the embodiments of the present application are: the present application changes the brittleness of the photopolymer coating formula so that it does not form a film. The photopolymer can not only meet the optical requirements of high transmittance, low refractive index, low haze, etc., but also has a higher Tg, low adhesion to the protective film, and does not stick to the protective film. The protective film is removed during transfer without damaging the photopolymer. The photopolymer itself is relatively brittle and can be transferred locally by hot stamping, cold transfer, etc., and by blunt cutting of the concave and convex parts of the die head. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] The technical solution of the present application will be further described in detail below with reference to the accompanying drawings and embodiments, in which:

[0050] FIG1 is a schematic diagram of manufacturing a solid holographic master according to an embodiment of the present application;

[0051] FIG2 is a schematic diagram of a photopolymer and positioning marks on a volume holographic master according to an embodiment of the present application;

[0052] FIG3 is a schematic diagram of a photopolymer film according to an embodiment of the present application;

[0053] FIG4 is a schematic diagram of coating of a photopolymer film according to an embodiment of the present application;

[0054] FIG5 is a schematic diagram of replicating a volume holographic grating through a volume holographic master using a photopolymer film according to an embodiment of the present application;

[0055] FIG6 is a schematic diagram of a continuous photopolymer film having a volume holographic grating and positioning marks replicated in an embodiment of the present application;

[0056] FIG7 is a schematic diagram of a process for further enhancing the volume holographic grating according to an embodiment of the present application;

[0057] FIG8 is a schematic diagram of transferring a photopolymer film onto a substrate according to an embodiment of the present application;

[0058] FIG9 is a physical picture of a photopolymer film with a volume holographic pattern after exposure according to an embodiment of the present application;

[0059] FIG10 is another physical image of a photopolymer film with a volume holographic pattern after exposure according to an embodiment of the present application;

[0060] FIG11 is a physical picture of the laser embossed holographic film currently on the market;

[0061] FIG12 is a physical picture of a silver salt material film currently on the market (observed under a non-point light source);

[0062] Figure 13 is a physical picture of the silver halide material film currently on the market (observed under a point light source). Best Mode for Carrying Out the Invention

[0063] It should be noted that, in the absence of conflict, the embodiments and features of the embodiments of the present application can be combined with each other. The preferred embodiments of the present application are now described in detail.

[0064] Photopolymers are typically exposed using visible light, using a monochromatic visible laser as the exposure source. The resulting volume holographic grating is internal to the photopolymer, and the refractive index modulation of the volume holographic grating relies on the refractive index difference between the photopolymerized portion and the supporting matrix. The equipment costs for photopolymer production are significantly lower than those for arrayed waveguides and surface relief grating waveguides. The largest expense is the laser, which costs only a few hundred thousand yuan. Exposure is performed using a laser light source, which is extremely fast, taking only a fraction of a second. Furthermore, the non-contact production process offers higher production efficiency and yield than arrayed waveguides and surface relief grating waveguides.

[0065] The photopolymer coating is very thin, requiring a transmittance exceeding 85%. The volume holographic grating is parallel to the coating surface and deeply embedded within the photopolymer, resulting in no visible roughness or discontinuities, making it an ideal material for optical waveguide lenses. However, due to limited photopolymer sources, demanding optical parameters, and immature manufacturing processes, volume holographic gratings have struggled to become a mainstream optical waveguide material, significantly limiting their application.

[0066] In the current production process, an unexposed photopolymer solution is applied to a substrate, such as an AR lens substrate, in a darkroom by screen printing, knife coating, or spin coating. After drying, the substrate is covered with a protective film. Before use, the substrate must be stored in a refrigerated environment at 4-8°C, away from light. To avoid affecting the soft, unexposed photopolymer coating, the substrates cannot be simply stacked on a flat surface. The process used in this application, however, involves applying an unexposed photopolymer solution to a protective film, then covering it with another protective film for protection. Then, exposure is performed to form a volume holographic grating within the photopolymer. After post-processing, the grating is transferred to a substrate, such as an AR lens, packaging material, or anti-counterfeiting material.

[0067] Of the two processes mentioned above, the first involves preparing the unexposed photopolymer as a low-concentration photopolymer solution to ensure uniform dispersion and minimized migration of components during the photochemical reaction. After coating, the solution is dried or air-dried to form a film. This unexposed material solution has a very low viscosity, making it easy to flow during coating. However, when coating curved surfaces, the required thickness cannot be maintained due to gravity. Therefore, this process is generally used for flat substrates, such as AR lenses. Furthermore, AR lenses are bulky after direct coating, making them unsuitable for stacking and storage before exposure. Furthermore, refrigeration is required for storage, placing high demands on warehouses for semi-finished products. During the exposure process, AR lenses are discontinuous, and laser interferometry imaging requires high vibration levels, which are further compounded by the vibrations generated by loading and unloading on the production line. This requires a period of quiet time (the time after the laser interferometry imaging process ends, after all imaging activity has ceased), resulting in low production efficiency.

[0068] The process used in this application involves coating an unexposed photopolymer on a protective film, drying it, and then applying another protective film to isolate it from oxygen and prevent oxygen inhibition of the photochemical reaction. The coated sandwich-structured photopolymer film is then fed into the exposure light path in a roll-to-roll manner. The volume holographic grating structure designed on the volume holographic grating master is then exposed onto the photopolymer using an interference method, thereby recording the volume holographic image information on the photopolymer film.

[0069] Photopolymer formulations typically consist of a photocuring system and a matrix. The photocuring system initiates a photocuring reaction at the bright fringes of the volume holographic grating, forming a high-refractive-index volume holographic grating structure. This creates a refractive index difference with the low-refractive-index matrix, known as refractive-index modulation, enabling reflection and refraction of light within a fixed, narrow wavelength range. However, in previous photopolymer formulations, the matrix was typically polyvinyl acetate (EVA) or a partially fluorinated polymer of EVA. Their refractive index ranges from 1.42 to 1.45. These film-forming resins have high transparency and a low refractive index, making them suitable for optical materials. However, they are brittle and have a low glass transition temperature (Tg), approximately 20-50°C. The photopolymer forms a film (i.e., a continuous, coherent layer) and adheres to the protective film after photocuring, making it difficult to completely remove. This makes it difficult to achieve both partial and complete transfer of the coating, forcing it to be die-cut and then laminarized, requiring die-cutting with a sharp blade and then transferred with the protective film. For this reason, ensuring smooth lamination is extremely difficult even on curved surfaces. Due to this production method, the protective film must be a highly transparent, corrosion-resistant optical film. Commonly used protective films include PET (polyester) and TAC (cellulose acetate). PET protective film has a high yield strength and low tensile strength. When laminating to curved surfaces with large curvatures, it will produce wrinkles that cannot be smoothed out. TAC protective film, on the other hand, has poor shear resistance and low tensile strength, making it easily broken when applied to curved surfaces. Furthermore, since the protective film is at least ten to one hundred microns thick, transmittance is also affected after lamination with the protective film.

[0070] The present invention provides a method for preparing a photopolymer film, comprising the steps of:

[0071] S100: methyl methacrylate, low Tg acrylic monomer, cross-linked acrylic monomer, rigid side group monomer, fluorine-containing or silicon-containing acrylic monomer and free radical thermal initiator are weighed in proportion by mass percentage to form a matrix; wherein, by mass percentage, methyl methacrylate is 40-85%, low Tg acrylic monomer is 0-50%, cross-linked acrylic monomer is 0-20%, rigid side group monomer is 5-20%, fluorine-containing or silicon-containing acrylic monomer is 4-20%, and free radical thermal initiator is 0.5-5%.

[0072] S200: heating the matrix in solvent 1 under reflux for 1-8 hours to obtain a non-film-forming matrix, wherein, by weight, solvent 1 accounts for 30-70% and matrix accounts for 30-70%. Solvent 1 may be butanone.

[0073] S300: weighing a non-film-forming matrix, a high-refractive index monomer, a visible light harvester, and a photoinitiator in proportion to obtain raw material 1; wherein, by mass percentage, the non-film-forming matrix comprises 40-80%, the high-refractive index monomer comprises 10-45%, the visible light harvester comprises 0.01-5%, and the photoinitiator comprises 1-10%.

[0074] S400: Raw material 1 is stirred and dissolved in solvent 2 to obtain a photopolymer solution. Solvent 2 can be added in an amount of 15-25%, with the remainder being raw material 1. Solvent 2 can be butanone, ethyl acetate, methanol, or dichloromethane.

[0075] S500: Producing a volume holographic grating master with positioning marks.

[0076] S600: coating the photopolymer solution on the protective film and drying it to form a photopolymer coating layer, and covering the photopolymer coating layer with the protective film to obtain a photopolymer intermediate.

[0077] S700: copying the volume holographic grating on the volume holographic grating master to a photopolymer intermediate to obtain a photopolymer film with the volume holographic grating.

[0078] S800: UV irradiation and heating of photopolymer film.

[0079] In the preparation method of the photopolymer film of the present application, a non-film-forming matrix is ​​used as the base material, wherein the non-film-forming matrix includes methyl methacrylate, low Tg acrylic monomer, cross-linked acrylic monomer, rigid side group monomer, fluorine-containing or silicon-containing acrylic monomer, and free radical thermal initiator. Such a photopolymer can not only meet the optical requirements of high transmittance, low refractive index, low haze, etc., but also has a high Tg, low adhesion to the protective film, and does not stick to the protective film. The protective film can be removed during transfer without damaging the photopolymer. The photopolymer itself is relatively brittle and can be transferred locally by hot stamping, cold transfer, etc., and by blunt cutting of the concave and convex parts of the die head.

[0080] Specifically, the preparation method of this application modifies the brittleness of the photopolymer coating formula, preventing it from forming a film during the preparation process (i.e., due to its high brittleness, it cannot form a continuous film layer and exist independently as a film, but must adhere to other surfaces, such as a protective film, to form a thin layer structure). Therefore, in step S600, the protective film is not adhered to the protective film. In terms of process, the photopolymer is applied to the protective film, dried, and then covered with the protective film to obtain a roll of unexposed photopolymer, which is suitable for assembly line production. This also reduces the difficulty and space required for refrigerated storage of semi-finished products, significantly saving production costs.

[0081] Specifically, in step S100 and step S300, the specific proportions, compositions, functions, etc. of the components are the same as those described below and will not be described in detail herein.

[0082] In step 200, an appropriate amount of butanone solvent can be selected, for example, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, and the matrix can be 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%; the amounts can also be, for example, as shown in Table 1 below, and the heating reflux time can be 1h, 1.5h, 2h, 2.5h, 3h, 3.5h, 4h, 4.5h, 5h, 5.5h, 6h, 6.5h, 7h, 7.5h, 8h.

[0083] The obtained non-film-forming matrix is ​​clear and transparent and has a certain viscosity, which is used for the subsequent preparation of the photopolymer, wherein the viscosity can be adjusted by adjusting the amount of the butanone solvent added. In the subsequent processing step S600, the butanone solvent evaporates during drying.

[0084] In step S400, the raw material is dissolved in the solvent and then stored in the dark at 0-4°C for later use. The viscosity of the photopolymer solution can be adjusted by adjusting the amount of the solvent.

[0085] In step 500, as shown in Figures 1 and 2 , when producing a volume holographic master for a photopolymer, the grating angle, distribution, and other parameters are first designed based on the specific requirements of the optical lens or holographic image. Object light and reference light are then incident on the photopolymer from both sides, forming alternating light and dark stripes within the photopolymer that are nearly parallel to the coating surface. Because the light enters from both sides, the photopolymer support, or protective film, must be transparent (transparent support). The light source used is a visible light laser. Due to the large incident angles of the reference and object light, the reproduced viewing angle is also wide, resulting in a more intense and realistic 3D effect for the holographic image. The resulting 3D image has pure, clear colors.

[0086] Because the volume holographic grating (VG) is deeply embedded in the photopolymer coating and does not form grooves on the coating surface, there is no need to wash out the master. Instead, the formed grating only needs to be chemically developed and fixed. The refractive index of the new polymer formed at the grating is different from that of the polymer in the matrix, creating a refractive index difference. This allows for refractive index modulation, which is then used for reading and writing. Refractive index modulation is the basis for storing information.

[0087] Volume holographic gratings can be processed using either wet or dry methods. Wet processing typically involves preparing a suitable developer and fixer solution to expand and strengthen the internal grating. Dry processing, typically involving UV light irradiation and heating, also promotes internal chemical reactions, fixing and strengthening the grating. During the design and production of a master, the positioning marks on the master are replicated one-to-one with the desired volume holographic grating onto a photopolymer. Specifically, the photopolymer solution can be coated onto a roll of protective film to produce a roll of photopolymer intermediates, facilitating continuous processing.

[0088] In step S600, as shown in Figures 3 and 4 , the photopolymer solution is a semi-fluid, viscous coating before the photocuring reaction. Therefore, after coating, a protective film (transparent carrier) must be applied immediately. This means that both the top and bottom protective films (transparent carrier) must be present before the product can be rolled up. Furthermore, photocuring of the photopolymer involves a free radical reaction, which is strongly inhibited by oxygen. Therefore, protective films are required for the reaction to occur effectively. These films serve to isolate the product from oxygen.

[0089] Specifically, the unexposed photopolymer solution can be applied to a transparent substrate, such as a transparent protective film (transparent carrier), in a darkened environment. After drying, a thin coating is formed, with a thickness ranging from a few microns to several hundred microns. Depending on the specific product, a sandwich structure can be formed by covering glass, a transparent resin plate, a transparent resin sheet, or another transparent film. In a preferred production process, the unexposed photopolymer solution is first applied to the entire surface of the substrate in a darkroom using a doctor blade coating device. The substrates used are primarily high-transmittance PET and TAC protective films. Full-roll coating is achieved using a roll-to-roll doctor blade coater. After coating, the substrate surface is completely covered with the photopolymer solution, with a wet coating thickness of 20-2000 microns. After drying, the substrate surface is completely covered with an unexposed photopolymer adhesive layer, with a dry coating thickness of 2-500 microns, typically around 10 microns. After applying a protective film, the substrate is rolled up or stacked for storage.

[0090] In step 700, as shown in FIG5 and FIG6, when the volume holographic grating and its positioning marks on the master are copied onto the photopolymer material, it is necessary to pass the reference light through the copied, unexposed photopolymer so that the reference light is reflected on the master. The object light formed after the reflection interferes with the reference light in the unexposed photopolymer to form a copied volume holographic grating.

[0091] During replication, a visible laser light source that can cooperate with the master is still used. The principle of replication is still the light and dark stripes formed by the interference of light, inducing photochemical reactions at the bright stripes to complete the volume holographic grating deeply buried in the photopolymer and parallel to the coating surface.

[0092] Because the laser light source needs to penetrate the photosensitive material and land on the master during replication, both the upper and lower supports (transparent carriers) of the photopolymer must be highly transparent. This dictates that the photopolymer support cannot be made of materials coated with release agents. This is because the opaque components of release agents can generate significant noise, resulting in blurred and scattered holographic images, poor quality, and even indiscernible images.

[0093] In step S800, as shown in FIG6, after the volume holographic grating in the photopolymer is exposed and replicated with the master, it needs to undergo post-processing such as UV irradiation fixation, heating strengthening, and UV irradiation reaction termination to stabilize the volume holographic grating.

[0094] As shown in Figure 8, the protective film for the photopolymer film can be in a roll format. A cold transfer adhesive or a composite hot melt adhesive is applied to the substrate (sheet or continuous substrate, etc.) to positionally transfer the photopolymer material with the volume holographic grating from the photopolymer film. Since the photopolymer with the volume holographic grating has protective films on both sides, one of the protective films is peeled off before use. Cold transfer adhesive or a composite hot melt adhesive is printed and applied to the substrate to be transferred. Simultaneously, the positioning marks copied along with the volume holographic grating are read. The device's concave and convex template edges are used to bluntly cut the brittle photopolymer material, resulting in a photopolymer material with neatly shaped edges. After the photopolymer material is transferred to the substrate, the cold transfer adhesive is cured by UV irradiation, or the hot melt adhesive is cured by cooling, ensuring a secure transfer of the photopolymer material to the substrate. Simultaneously, the other protective film is peeled off, completing the transfer of the photopolymer to the substrate without the upper and lower protective films. That is, the photopolymer on such a substrate is obtained by transfer and has no protective film, so it has a small thickness and a small sense of concave and convex, and the holographic image is clear and three-dimensional.

[0095] The present application provides a photopolymer for use in the above-mentioned method for preparing a photopolymer film. The photopolymer comprises, by weight, 50-80% matrix and 20-50% complexing base. The matrix may be 50%, 55%, 60%, 65%, 70%, 75%, or 80%, and the complexing base may be 20%, 25%, 30%, 35%, 40%, 45%, or 50%. Preferably, the matrix is ​​60-75% and the complexing base is 25-40%. More preferably, the matrix is ​​66.9% and the complexing base is 33.1%.

[0096] The composite base includes 70-90% of a high refractive index monomer, 0.1-10% of a visible light capture agent, and 9-20% of a photoinitiator.

[0097] Specifically, by mass percentage, the high refractive index monomer may account for 70%, 72%, 75%, 78%, 80%, 83%, 85%, 87%, or 90% of the composite base. The visible light capture agent may account for 0.1%, 0.5%, 1%, 1.5%, 2%, 3%, 4%, 4.5%, 5%, 6%, 7%, 8%, 9%, or 10% of the composite base. The photoinitiator may account for 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, or 20% of the composite base.

[0098] Wherein, by mass percentage, the matrix includes 40-85% methyl methacrylate, 0-50% low Tg acrylic monomer, 0-20% cross-linked acrylic monomer, 5-20% rigid side group monomer, 4-20% fluorine-containing or silicon-containing acrylic monomer, and 0.5-5% free radical thermal initiator. Specifically, by mass percentage, the proportion of methyl methacrylate in the matrix can be 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%; the proportion of low Tg acrylic monomer in the matrix can be 0%, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%; the proportion of cross-linked acrylic monomer in the matrix can be 0%, 5%, 10%, 15%, 20%; the proportion of rigid side group monomer in the matrix can be 5%, 8%, 10%, 12%, 15%, 17%, 20%; the proportion of fluorine-containing or silicon-containing acrylic monomer in the matrix can be 4%, 8%, 10%, 12%, 15%, 17%, 20%; the proportion of free radical thermal initiator in the matrix can be 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%.

[0099] Generally speaking, during the preparation process, the non-film-forming matrix comprises 30-70% matrix and 30-70% solvent 1. After the non-film-forming matrix is ​​used to prepare a photopolymer solution, solvent 1 and solvent 2 are still present, meaning the photopolymer solution comprises 15-25% solvent 2, with the remainder being the non-film-forming matrix and the compounding base. The non-film-forming matrix comprises solvent 1 and matrix, and the specific components of the matrix and compounding base are as described above and will not be further described here. After the photopolymer solution is dried, solvent 1 and solvent 2 evaporate, resulting in a thin film of photopolymer. At this point, the photopolymer comprises 50-80% matrix and 20-50% compounding base.

[0100] The photopolymer of the present application is based on a non-film-forming matrix, wherein the non-film-forming matrix includes 30-70% of a matrix and 30-70% of a solvent. During the preparation process, the solvent in the non-film-forming matrix evaporates, leaving only the matrix. The matrix includes methyl methacrylate, a low Tg acrylic monomer, a cross-linked acrylic monomer, a rigid side group monomer, a fluorine-containing or silicon-containing acrylic monomer, and a free radical thermal initiator. Such a photopolymer can meet optical requirements such as high transmittance, low refractive index, and low haze, and has a high Tg, low adhesion to the protective film, and does not stick to the protective film. When removing the protective film during transfer, the photopolymer will not be damaged. The photopolymer itself is relatively brittle and can be transferred locally by hot stamping, cold transfer, etc., and by blunt cutting of the concave and convex parts of the die head.

[0101] Specifically, the present application changes the brittleness of the photopolymer coating formula so that it does not form a film (i.e., it does not form a continuous film layer) and does not adhere to the protective film. In terms of process, it is coated on the protective film and dried, and then covered with the protective film to obtain a roll of unexposed photopolymer, which is suitable for assembly line production. It also reduces the difficulty and space required for refrigerated storage of semi-finished products, greatly saving production costs. Then, a volume holographic grating master with a volume holographic grating is produced and designed. On a continuous device, a single-beam laser is used to copy the volume holographic grating of the volume holographic grating master to the photopolymer roll material and post-process it. Because the single-beam laser has no strict requirements for vibration, it does not require static table time, allowing continuous production and greatly improving production efficiency. After dry post-processing and curing (heating and UV curing), the protective film on one side can be peeled off, and the required part of the photopolymer with a volume holographic grating structure can be partially transferred by UV cold transfer, hot stamping, etc. through a die with a concave and convex surface or a flat die, and the other protective film can be peeled off at the same time. This not only solves the problem of making photopolymer holographic gratings on curved surfaces, but also eliminates the need for a protective film, thereby improving transmittance.

[0102] The non-film-forming matrix of the present application is based on the high transparency of acrylic polymers, with methyl methacrylate having a relatively high Tg as the main body. A small amount of other monomers with rigid side groups are added to the formula, such as isobornyl methacrylate, dicyclopentadiene and its derivatives, adamantyl acrylates, etc. The rigid monomers with large side groups can reduce the rotational mobility of the molecular chain, freeze the molecular chain, and greatly increase the brittleness of the synthesized non-film-forming matrix, making it easy to break, which is conducive to blunt cutting and separation. During transfer, the edges can be cut very neatly by a blunt instrument during local transfer die-cutting.

[0103] Because rigid side-group monomers and polymers with cyclic side groups have a relatively high refractive index, acrylic monomers containing fluorine or silicon need to be added to reduce the refractive index of the non-film-forming matrix and further reduce the adhesion between the non-film-forming matrix and the protective film, thereby facilitating its release. Optical materials have very high transmittance requirements, and the only commercially available protective films that have a certain strength and can support roll-to-roll coating and drying are PET or TAC protective films without release agent coatings. Protective films with release agent coatings, typically silicone oil and fluoride, have low adhesion and can easily fall off the photopolymer, causing black spot defects. Furthermore, these release-coated protective films have low transmittance, typically only around 80%. The release agent coating also creates a high haze, which can introduce significant noise during optical capture, blurring the volume holographic image.

[0104] Specifically, the application uses methyl methacrylate (MMA), a relatively high Tg acrylic monomer, as the backbone. The resulting polymethyl methacrylate (PMMA) produced by cross-linking and polymerizing methyl methacrylate has high transmittance (approximately 92%) and a relatively high Tg (approximately 105°C). It is also highly brittle and has relatively weak impact resistance, making it suitable as a base material for brittle photopolymers. Specifically, the application uses methyl methacrylate (MMA) as the primary component, adding a small amount of rigid side-group monomers with large cyclic groups to further enhance the brittleness of the photopolymer. Fluorine- or silicon-containing acrylic monomers are then added to reduce the adhesion between the photopolymer and the protective film, allowing for complete removal of the protective film. This application involves the oily free radical polymerization of acrylic monomers, and the polymerization reaction can be initiated using butanone as a solvent and a free radical thermal initiator.

[0105] Specifically, by mass percentage, the proportion of methyl methacrylate in the matrix can be 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%; the proportion of low Tg acrylic monomer in the matrix can be 0%, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%; the proportion of cross-linked acrylic monomer in the matrix can be 0%, 5%, 10%, 15%, 20%; the proportion of rigid side group monomer in the matrix can be 5%, 8%, 10%, 12%, 15%, 17%, 20%; the proportion of fluorine-containing or silicon-containing acrylic monomer in the matrix can be 4%, 8%, 10%, 12%, 15%, 17%, 20%; the proportion of free radical thermal initiator in the matrix can be 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%.

[0106] Specifically, by mass percentage, the matrix comprises 69.4% methyl methacrylate, 6% butyl acrylate, 0% hydroxyethyl methacrylate, 13.6% isobornyl methacrylate, 10% dodecafluoroheptyl methacrylate, 0.7% dibenzoyl peroxide, and 0.7% N,N-dimethyl-p-toluidine. With this composition, the non-film-forming matrix exhibits a break elongation of only 8.02% and a peel strength of only 0.23 N / 25 mm. The resulting photopolymer is brittle and easily fractured, making it easier to separate using blunt cutting techniques and preventing adhesion to protective films.

[0107] Low-Tg acrylic monomers are one or more of ethyl acrylate (EA), butyl acrylate (BA), isooctyl acrylate (2-EHA), lauryl acrylate, and dodecyl acrylate. The longer the carbon chain of a low-Tg acrylic monomer, the greater its flexibility, with the flexibility ranking being ethyl acrylate (EA) < butyl acrylate (BA) < isooctyl acrylate (2-EHA) < lauryl acrylate < dodecyl acrylate. The greater the flexibility, the greater the amount added, the less brittle the non-film-forming matrix, the stronger the adhesion to the protective film, and the lower the glass transition temperature. Therefore, depending on the specific protective film, one or more of these monomers can be selected or omitted to ensure that the photopolymer adheres appropriately to the protective film, achieving coverage and protection, while also remaining non-adherent to the protective film.

[0108] Cross-linking acrylic monomers can be one or more of hydroxyethyl acrylate (HEA), hydroxyethyl methacrylate (HEMA), acrylamide (AAM), hydroxymethyl acrylamide (NMA), diacetone acrylamide (DAAM), ethyl acetoacetate methacrylate (AAEM), glycidyl methacrylate (GMA), and dimethylaminoethyl methacrylate (DMAEMA). These cross-linking acrylic monomers contain functional groups such as amide, amino, and epoxy groups, providing cross-linking functionality, and can be selected based on different product requirements. Certain cross-linking groups can improve the hardness and weather resistance (high and low temperature resistance, light, UV rays, oxidation, water, solvents, etc.) of the non-film-forming matrix, reduce brittleness, improve heat resistance, and enhance adhesion to the protective film. These cross-linking acrylic monomers serve as a regulator and can be added or omitted depending on the protective film and the application environment.

[0109] The rigid side group monomer is one or more of isobornyl methacrylate (IBOA), dicyclopentadiene and its derivatives, and adamantyl acrylates, with dicyclopentadiene being a bifunctional monomer. The adamantyl acrylate can specifically be adamantane methyl acrylate. The structural formulas of isobornyl methacrylate (IBOA), dicyclopentadiene, and adamantane methyl acrylate are as follows: Isoborneol acrylate Dicyclopentadiene Adamantane methyl acrylate.

[0110] Fluorinated acrylic monomers are one or more of trifluoroethyl acrylate (TFEA), trifluoroethyl methacrylate (TFEMA), hexafluorobutyl acrylate (HFBA), and dodecafluoroheptyl methacrylate (DFMA). Silicone-containing acrylic monomers are one or more of methylvinylchlorosilane, vinyltrichlorosilane, and vinyltriethoxysilane (VTES). These silicone-containing acrylic monomers are silicone monomers with vinyl groups. Fluorinated or silicone-containing acrylic monomers reduce the adhesion between the non-film-forming substrate and the protective film, allowing for complete removal of the protective film.

[0111] The free radical thermal initiator is one or more of azobisisobutyronitrile, azobisisoheptanenitrile and dimethyl azobisisobutyrate, hydrogen peroxide, ammonium persulfate, potassium persulfate, benzoyl peroxide, tert-butyl benzoyl peroxide, and methyl ethyl ketone peroxide. One or more of them can be selected according to needs.

[0112] Specifically, dibenzoyl peroxide (BPO) and N,N-dimethylaniline (DMA) or dimethyl-β-propionate thiazolinone (DMPT) are preferred in this application. They can be used for room-temperature polymerization of methyl methacrylate and other monomers. Specifically, the decomposition and polymerization rates of the BPO-DMPT initiation system are faster than those of the BPO-DMA initiation system, and the color stability of the polymer using DMPT is better than that using DMA.

[0113] To prepare the non-film-forming matrix, the matrix components are added to a butanone solvent and heated under reflux for 1-8 hours to obtain a clear, transparent, and viscous non-film-forming matrix solution. This non-film-forming matrix solution can be directly used to prepare the photopolymer. The butanone solvent evaporates during subsequent preparation steps.

[0114] The high refractive index monomer can be one or more of phenyl bisether fluorene, phenol ethoxy acrylate, ethoxy bisphenol fluorene diacrylate, vinyl carbazole, and sulfur-containing acrylate monomers. The visible light harvester can be an acridine dye (460 nm), a xanthene dye (565 nm), a thiazine dye (668 nm), and the like, such as methylene blue, erythrosine b, eosin, and azure I.

[0115] The photoinitiator can be a diaryl titanocene such as 6, bis-2,6-difluoro-3-pyrrolphenyl titanocene (GR-FMT, 784), an aryl ferrocenium salt such as η6-isopropylbenzene (II) hexafluorophosphate (i-261), a UV initiator bisimidazole, a borate, etc.

[0116] The above high-refractive index monomer, visible light harvester, and photoinitiator are added to the non-film-forming matrix solution containing butanone solvent. An appropriate solvent (e.g., 15-25% solvent 2) such as butanone, ethyl acetate, methanol, or dichloromethane is then added, with the remainder being the non-film-forming matrix and the compounding base. The concentrations are adjusted and the solution is stirred in a darkroom at room temperature until completely dissolved to obtain a photopolymer solution. This solution is then stored in the dark at 0-4°C until ready for use. Stirring and storing in the dark prevents external light from initiating polymerization. For use, the photopolymer solution is coated onto a substrate such as a glass plate or protective film. After covering the protective film, the solution is exposed to a 532nm green laser. The diffraction efficiency can reach over 85%.

[0117] The present application also discloses a non-film-forming matrix for the above-mentioned photopolymer, which comprises, by weight percentage, 30-70% matrix and 30-70% solvent 1. Solvent 1 may be 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, or 70%, and matrix may be 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, or 70%. The matrix comprises:

[0118] Methyl methacrylate 40-85%

[0119] Low Tg acrylic monomer 0-50%

[0120] Cross-linked acrylic acid monomer 0-20%

[0121] Rigid side group monomer 5-20%

[0122] Fluorine-containing or silicon-containing acrylic monomer 4-20%

[0123] Free radical thermal initiator 0.5-5%.

[0124] The proportion of methyl methacrylate in the matrix can be 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, and 85%; the proportion of low Tg acrylic monomer in the matrix can be 0%, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, and 50%; the proportion of cross-linked acrylic monomer in the matrix can be 0%, 5%, 10%, 15%, and 20%; the proportion of rigid side group monomer in the matrix can be 5%, 8%, 10%, 12%, 15%, 17%, and 20%; the proportion of fluorine-containing or silicon-containing acrylic monomer in the matrix can be 4%, 8%, 10%, 12%, 15%, 17%, and 20%; the proportion of free radical thermal initiator in the matrix can be 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, and 5%.

[0125] The matrix is ​​the matrix in the above-mentioned photopolymer. Its component composition, specific types of components, and effects are the same as those mentioned above and will not be described in detail here.

[0126] The present application also discloses a photopolymer film, which is made by the above-mentioned photopolymer film preparation method, and includes the above-mentioned photopolymer and two layers of protective films, wherein the two layers of protective films respectively cover two sides of the photopolymer.

[0127] When preparing the photopolymer film, a volume holographic grating master with positioning marks is first designed and manufactured. The volume holographic grating master has the required volume holographic image information.

[0128] The unexposed photopolymer solution is applied to a transparent protective film using a roll-to-roll blade coater in a dark environment. After drying, a thin coating with a thickness ranging from a few microns to several hundred microns is formed. Another layer of transparent protective film is then applied to form a sandwich structure. Highly transparent PET or TAC protective films are preferred. However, glass, transparent resin plates, or transparent resin sheets can also be used in place of or in combination with the protective film.

[0129] This application uses a PET protective film as an example of a carrier. After the photopolymer solution is coated on the PET protective film and dried, it is covered with another layer of PET protective film and rolled into a roll. During exposure and replication, the rolled photopolymer film continuously uses a single beam of laser to replicate the volume holographic grating on the volume holographic grating master onto the photopolymer film. When replicating the photopolymer volume holographic grating, it is necessary to pass a reference light through the photopolymer that is not exposed during replication so that it is reflected on the volume holographic grating master. The object light formed after reflection interferes with the reference light in the photopolymer, forming a replicated volume holographic grating in the photopolymer. During replication, a visible laser light source that can cooperate with the volume holographic grating master is still used. The principle of replication is still to form light and dark stripes through the interference of light, and to induce a photochemical reaction at the light stripes to form a volume holographic grating deeply buried in the photopolymer and parallel to the coating surface.

[0130] Since the laser light source needs to penetrate the photopolymer and fall onto the volume holographic grating master during replication, the upper and lower carriers of the photopolymer need to have high transparency. This determines that the carrier of the photopolymer cannot be a material coated with a release agent. Combined with the above, because the opaque part of the release agent will generate a lot of noise, the hologram after replication will be blurred and scattered, and the holographic image quality will be very poor, or even impossible to clearly identify. The photopolymer of the present application can avoid sticking to the protective film without using a release agent, avoiding the interference of the release agent when replicating the volume holographic grating.

[0131] After the photopolymer is composited with the volume holographic grating master and exposed for replication, it undergoes post-processing, including UV irradiation fixation, heating for strengthening, and UV irradiation for reaction termination. The resulting product, a photopolymer film, consists of a replica of the volume holographic grating hologram, sandwiched between protective films on top and bottom.

[0132] The comparison between the photopolymer film of this application and other volume holographic products currently on the market is shown in the following table:

[0133] The present application also discloses a photopolymer substrate, comprising the above-mentioned photopolymer, wherein the photopolymer is solidified on the substrate. When the photopolymer film is used, one layer of the protective film is first peeled off, and a cold stamping adhesive or a composite hot melt adhesive is applied to the sheet or continuous substrate. At the same time, the positioning mark on the photopolymer, which is produced by photographing the volume holographic grating, is read. By bluntly cutting the edges of the concave and convex templates, the brittle photopolymer is cut to obtain neatly shaped edges. At this time, after curing the UV cold transfer adhesive with a UV light source or curing the hot melt adhesive by cooling, the photopolymer is firmly transferred to the substrate. During the transfer process, another layer of the protective film is simultaneously peeled off, and a photopolymer substrate without upper and lower protective films can be obtained.

[0134] The printing materials can be AR lenses, AR-HUD displays, transparent displays, projected transparent HUD displays, AR smart helmet display masks, security camera AR display lenses, airborne sight displays, individual soldier sights, film lenses and other transparent and display screens, as well as various packaging materials and anti-counterfeiting materials.

[0135] The technical solution of the present application is illustrated below through specific examples and comparative examples of non-film-forming substrates.

[0136] Examples 1-3

[0137] In Examples 1-3, the components and amounts of the non-film-forming matrix in Table 1 were added to a flask, and the mixture was kept refluxed at 110 degrees Celsius for 3.5 hours. The non-film-forming matrix solution was taken out, air-dried and bonded to a 25 mm test piece, and then its elongation at break and 90-degree peel strength were tested using a tensile tester to identify its brittleness and peelability. The results are shown in Table 1.

[0138] Comparative Example

[0139] Comparative Example: 50 g of commercially available EVA resin (LG Chemical, ES28005) was added to a flask, along with 50 g of butanone. The mixture was refluxed at 110 degrees Celsius for 3.5 hours. The non-film-forming matrix solution was removed and air-dried and bonded to a 25 mm test piece. The elongation at break and 90-degree peel strength were then tested using a tensile testing machine to identify brittleness and peelability. The results are shown in Table 1.

[0140]

[0141] Furthermore, 50 g of each of the non-film-forming matrices prepared in Examples 1-3 above were added, respectively, to which 3 g of phenolic ethoxy acrylate, 7.54 g of vinyl carbazole, 1.8 g of bis-2,6-difluoro-3-pyrrolphenyl titanocene (GR-FMT, 784), 0.028 g of erythrosine b, and 28 g of butanone were added. After stirring and dissolving at room temperature, the mixture was coated on a glass plate or a protective film. After covering the protective film, the mixture was exposed with a 532 nm green laser, and the diffraction efficiency could reach over 85%.

[0142] It should be understood that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Those skilled in the art may modify the technical solutions described in the above embodiments or make equivalent replacements for some of the technical features therein; and all these modifications and replacements shall fall within the scope of protection of the claims attached to this application.

Claims

1. A method for preparing a photopolymer film, characterized in that: Includes steps: By mass percentage, methyl methacrylate, low Tg acrylic monomer, cross-linked acrylic monomer, rigid side group monomer, fluorine-containing or silicon-containing acrylic monomer and free radical thermal initiator are weighed in proportion to form a matrix; wherein, by mass percentage, methyl methacrylate is 40-85%, low Tg acrylic monomer is 0-50%, cross-linked acrylic monomer is 0-20%, rigid side group monomer is 5-20%, fluorine-containing or silicon-containing acrylic monomer is 4-20%, and free radical thermal initiator is 0.5-5%; The matrix is ​​heated under reflux in solvent 1 for 1-8 hours to obtain a non-film-forming matrix; Weigh a non-film-forming matrix, a high-refractive index monomer, a visible light harvester and a photoinitiator in proportion to obtain the first raw material; wherein, by mass percentage, the non-film-forming matrix comprises 40-80%, the high-refractive index monomer comprises 10-45%, the visible light harvester comprises 0.01-5%, and the photoinitiator comprises 1-10%; The raw material 1 is stirred and dissolved in the solvent 2 to obtain a photopolymer solution; Making a volume holographic grating master with positioning marks; coating a photopolymer solution on a protective film and drying the solution to form a photopolymer coating, and covering the photopolymer coating with a protective film to obtain a photopolymer intermediate; Copying the volume holographic grating on the volume holographic grating master to a photopolymer intermediate to obtain a photopolymer film with the volume holographic grating; UV irradiation and heating of photopolymer films.

2. A photopolymer, characterized in that: By mass percentage, it includes 50-80% of the matrix and 20-50% of the compound base; wherein the compound base includes: High refractive index monomer 70-90% Visible light capture agent 0.1-10% Photoinitiator 9-20%; Wherein, by mass percentage, the matrix includes: Methyl methacrylate 40-85% Low Tg acrylic monomer 0-50% Cross-linked acrylic acid monomer 0-20% Rigid side group monomer 5-20% Fluorinated or silicon-containing acrylic monomers 4-20% Free radical thermal initiator 0.5-5%.

3. The photopolymer according to claim 2, characterized in that The low Tg acrylic monomer is one or more of ethyl acrylate (EA), butyl acrylate (BA), isooctyl acrylate (2-EHA), lauryl acrylate, and dodecyl acrylate.

4. The photopolymer according to claim 3, characterized in that The cross-linked acrylic monomer is one or more of hydroxyethyl acrylate (HEA), hydroxyethyl methacrylate (HEMA), acrylamide (AAM), hydroxymethyl acrylamide (NMA), diacetone acrylamide (DAAM), ethyl acetoacetate methacrylate (AAEM), glycidyl methacrylate (GMA), and dimethylaminoethyl methacrylate (DMAEMA); and / or The rigid side group monomer is one or more of isobornyl methacrylate (IBOA), dicyclopentadiene and its derivatives, and adamantyl acrylate.

5. The photopolymer according to claim 4, characterized in that The fluorine-containing acrylic monomer is one or more of trifluoroethyl acrylate (TFEA), trifluoroethyl methacrylate (TFEMA), hexafluorobutyl acrylate (HFBA), and dodecafluoroheptyl methacrylate (DFMA); The silicon-containing acrylic monomer is one or more of methylvinylchlorosilane, vinyltrichlorosilane, and vinyltriethoxysilane (VTES).

6. The photopolymer according to claim 5, characterized in that The free radical thermal initiator is one or more of azobisisobutyronitrile, azobisisoheptanenitrile and dimethyl azobisisobutyrate, hydrogen peroxide, ammonium persulfate, potassium persulfate, benzoyl peroxide, tert-butyl benzoyl peroxide, methyl ethyl ketone peroxide, dibenzoyl peroxide, N,N-dimethylaniline or dimethyl-β-thiophene propionate.

7. The photopolymer according to claim 6, characterized in that By mass percentage, the matrix comprises: Methyl methacrylate 69.4% Butyl acrylate 6% Hydroxyethyl Methacrylate 0% Isobornyl methacrylate 13.6% Dodecafluoroheptyl methacrylate 10% Benzoyl peroxide 0.7% N,N-dimethyl-p-toluidine 0.7%.

8. A non-film-forming matrix for a photopolymer, characterized in that: By mass percentage, it includes 30-70% of matrix and 30-70% of solvent 1, wherein the matrix includes: Methyl methacrylate 40-85% Low Tg acrylic monomer 0-50% Cross-linked acrylic acid monomer 0-20% Rigid side group monomer 5-20% Fluorinated or silicon-containing acrylic monomers 4-20% Free radical thermal initiator 0.5-5%.

9. A photopolymer film, characterized in that: It comprises the photopolymer as claimed in any one of claims 2 to 6 and two layers of protective films, wherein the two layers of protective films respectively cover two sides of the photopolymer.

10. A photopolymer substrate, characterized in that: The method comprises a substrate and the photopolymer according to any one of claims 2 to 6, wherein the photopolymer is cured on the substrate and has a volume holographic grating.

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