An organometallic complex, an image storage material based on the organometallic complex, and its preparation and application

Abstract

The present invention belongs to the technical field of functional materials, and more specifically, relates to an organometallic complex, an image storage material based on the organometallic complex, and its preparation and application. The dual image storage material is prepared by an orthogonal photoreaction from 0.1 to 10 parts by weight of an organometallic complex, 20 to 75 parts by weight of a polymer binder, 20 to 75 parts by weight of a photopolymerizable monomer, and 0.1 to 5 parts by weight of a photoinitiator. The dual image storage material can display a holographic image visible to the naked eye under natural light, present a luminescent image under ultraviolet light, and the color of the luminescent image can be precisely regulated by changing the content of the organometallic complex and / or the composition of the polymer binder. The dual image storage material can be applied to fields such as high-end anti-counterfeiting, information storage, and intelligent display.

Description

Technical Field

[0001] The present invention belongs to the technical field of functional materials, and more specifically, relates to an organometallic complex, an image storage material based on the organometallic complex, and its preparation and application. Background Art

[0002] The image storage materials with multi-image non-crosstalk integration have the advantages of large information storage capacity, high security level, etc., are difficult to forge, and have received unprecedented attention in the high-end anti-counterfeiting field. For example, Patent CN110699069A blends an organometallic complex, a photo-base generator with liquid crystal, a photopolymerizable monomer, and an initiator to prepare a material integrating holographic and luminescent dual images; Patent CN 110527523A blends an organic fluorescent material with liquid crystal, a photopolymerizable monomer, and an initiator to prepare a material integrating holographic and fluorescent dual images; Patent CN 111218017A blends upconversion nanoparticles with liquid crystal, a photopolymerizable monomer, and an initiator to prepare a material integrating holographic and upconversion luminescence dual images. The dual-image storage materials involved in the above patents realize the orthogonal display of dual patterns at the same spatial position through the orthogonal storage of luminescent (fluorescent / upconversion luminescence) images and holographic images. However, in the current holographic, luminescent (fluorescent / upconversion luminescence) dual-image storage materials, the color of the luminescent image is single and difficult to regulate, which limits the further improvement of anti-counterfeiting security.

[0003] Organometallic complexes have rich photophysical / chemical properties, high luminescence quantum yields, excellent resistance to photobleaching, etc. In particular, organometallic complexes based on divalent platinum not only have excellent luminescence properties, but also their luminescence behavior highly depends on the intermolecular distance and Pt…Pt interaction, which provides the possibility for regulating the luminescence behavior of luminescent images. However, the storage of holographic images is realized through photopolymerization reactions, and it is still very difficult to design platinum complexes that can continue to store luminescent images after holographic photoreaction. At the same time, platinum complexes are extremely prone to aggregation and have poor compatibility with the holographic composite system, which also results in the difficulty of storing high-quality holographic images. Summary of the Invention

[0004] Aiming at the defects of the prior art, the purpose of the present invention is to provide an organometallic complex, an image storage material based on the organometallic complex, and its preparation and application, so as to solve the technical problems such as the single color and difficult regulation of the luminescent image in the prior art dual-image storage materials.

[0005] To achieve the above purpose, the present invention provides an organometallic complex having one of the Pt-1 and Pt-2 structures shown as follows:

[0006]

[0007] Wherein, R1 is hydrogen, methyl, ethyl, trifluoromethyl, nitro, amino or phenyl; R 2 and R 3 are each independently hydrogen or cyano; R 4 is n-octyl, n-octyloxy, isooctyl, isooctyloxy, n-dodecyl, n-dodecyloxy, n-hexadecyl, n-hexadecyloxy, tetraethylene glycol or citronellyl; m is any integer from 1 to 5; n is 0 or 1; p is 0 or 1.

[0008] Preferably, R 4 is isooctyloxy or n-hexadecyloxy, and m is any integer from 3 to 5. The number of flexible chains reaching 3 to 5 makes the organometallic complex have good solubility.

[0009] Preferably, R 4 is tetraethylene glycol or citronellyl, and m is any integer from 1 to 5.

[0010] According to another aspect of the present invention, there is provided a dual-image storage material with adjustable emission color, which is prepared by an orthogonal photoreaction from 0.1 to 10 parts by weight of the organometallic complex as described in any one of claims 1 to 3, 20 to 75 parts by weight of a polymer binder, 20 to 75 parts by weight of a photopolymerizable monomer, and 0.1 to 5 parts by weight of a photoinitiator;

[0011] When in use, the image storage material uses the emission color as encrypted information, which can display a holographic image visible to the naked eye under natural light, present an emission image under ultraviolet light, and the color of the emission image can be adjusted by changing the content of the organometallic complex and / or the type of the polymer binder;

[0012] Preferably, the dual-image storage material is prepared by an orthogonal photoreaction from 0.5 to 8 parts by weight of the organometallic complex, 30 to 70 parts by weight of a polymer binder, 30 to 70 parts by weight of a photopolymerizable monomer, and 1 to 5 parts by weight of a photoinitiator.

[0013] Preferably, the refractive index of the polymer binder is less than 1.5, and preferably it is at least one of polymethyl methacrylate, polyethyl methacrylate, polybutyl methacrylate, polyisobutyl methacrylate, polyglycidyl methacrylate, poly(methyl methacrylate-co-ethyl acrylate), polyvinyl acetate, polystyrene and polyvinyl chloride.

[0014] Further preferably, the polymer binder is one or more of polymethyl methacrylate, polyethyl methacrylate, polybutyl methacrylate, polyisobutyl methacrylate, glycidyl methacrylate, poly(methyl methacrylate-co-ethyl acrylate), and polyvinyl acetate. Experiments have found that when these types of polymer binders are selected, the color can be regulated within a relatively wide content range.

[0015] Preferably, the refractive index of the photopolymerizable monomer is greater than 1.5, and it is preferably at least one of ethoxyphenyl acrylate, o-phenylphenylethoxy acrylate, 2-phenylethyl acrylate, 2-phenoxyethyl acrylate, 2-[4-(1-methyl-1-phenylethyl)phenoxy]ethyl acrylate, 2-naphthyl acrylate, and 2-(1-naphthyloxy)ethyl acrylate.

[0016] Preferably, the photoinitiator includes a photosensitizer and a co-initiator. The photosensitizer is at least one of 3,3'-carbonylbis(7-diethylaminocoumarin), Irgacure 784, sodium tetraiodotetrachlorofluorescein, methylene blue, new methylene blue, safranin O, and eosin Y; the co-initiator is one or several of triethanolamine, triisopropanolamine, methyldiethanolamine, chlorodiphenyliodonium salt, and diphenyliodonium hexafluorophosphate;

[0017] Preferably, the photoinitiator is a ternary initiation system, including a photosensitizer, an amine, and a diphenyliodonium salt co-initiator, such as a combination of 3,3'-carbonylbis(7-diethylaminocoumarin), triethanolamine, and chlorodiphenyliodonium salt.

[0018] According to another aspect of the present invention, a method for preparing the image storage material is provided, including the following steps:

[0019] (1) Dissolve the components of the dual image storage material in an organic solvent to obtain a homogeneous mixture;

[0020] (2) Prepare a holographic photosensitive film by coating and solvent evaporation of the homogeneous mixture obtained in step (1), and then expose it to coherent laser light. A holographic material storing a holographic image is obtained through the polymerization reaction of the photopolymerizable monomer;

[0021] (3) Post-cure the holographic material obtained in step (2) with white light to further react the unreacted photopolymerizable monomer and fix the holographic image to obtain a holographic material after fixing the holographic image;

[0022] (4) Place the holographic material after fixing the holographic image in step (3) under a mask and irradiate it with ultraviolet light. A luminescent image is stored through the double bond cycloaddition reaction of the organometallic complex to obtain a dual image storage material that stores both a holographic image and a luminescent image.

[0023] Preferably, the organic solvent in step (1) is one or more of volatile methanol, ethanol, dichloromethane, chloroform, tetrahydrofuran, ethyl acetate, and acetone.

[0024] Preferably, the wavelength of the coherent laser in step (2) is one of 460 nm, 532 nm, or 640 nm, the light intensity is 0.1 - 5 mW / cm², and the exposure time is 5 - 120 seconds;

[0025] The wavelength of the ultraviolet light in step (4) is 200 - 380 nm, the light intensity is 5 - 200 mW / cm², and the irradiation time is 1 - 30 minutes.

[0026] According to another aspect of the present invention, there is provided an application of the described image storage material in the field of anti - counterfeiting.

[0027] Preferably, the dual - image storage material is used in the high - end anti - counterfeiting field. The holographic image displayed under visible light is used as the first anti - counterfeiting means, the luminescent image displayed under ultraviolet light with an intensity less than 1 mW / cm² is used as the second anti - counterfeiting means, and the color of the luminescent image determined by the composition of the organometallic complex and / or the polymer binder therein is used as the third anti - counterfeiting means.

[0028] Generally speaking, compared with the prior art by the above - conceived technical solution of the present invention, the following

[0029] Advantages are obtained:

[0030] (1) The present invention designs a class of organometallic complexes that have good compatibility with the holographic composite system and do not reduce the holographic image storage quality. A photoreactive group capable of in - situ regulating the luminescence behavior is introduced into the organometallic complex. Through a cycloaddition reaction orthogonal to the holographic photopolymerization reaction, a luminescent image is stored after storing the holographic image.

[0031] (2) The present invention provides a dual - image storage material with the emission color as the encryption information and the emission color being adjustable. It is prepared by an orthogonal photoreaction from 0.1 - 10 parts by weight of an organometallic complex, 20 - 75 parts by weight of a polymer binder, 20 - 75 parts of a photopolymerizable monomer, and 0.1 - 5 parts by weight of a photoinitiator. It can display a holographic image visible to the naked eye under natural light, present a luminescent image under ultraviolet light, and the color of the luminescent image can be precisely regulated by changing the composition of the organometallic complex or the polymer binder.

[0032] (3) The dual-image storage material provided by the present invention can be used in the high-end anti-counterfeiting field. The holographic image displayed under visible light is used as the first anti-counterfeiting means, the luminescent image displayed under ultraviolet light with an intensity less than 1 mW / cm² is used as the second anti-counterfeiting means, and the color of the luminescent image determined by the composition of the organometallic complex and the polymer binder is used as the third anti-counterfeiting means. The corresponding relationship between the composition of the organometallic complex and the polymer binder and the luminescent color of the dual-image storage material is established. By regulating the content of the organometallic complex and / or the type of the polymer binder, precise regulation of the luminescent color of the luminescent image and triple security anti-counterfeiting functions are achieved. Description of the Drawings

[0033] Figure 1 It is a diffraction efficiency test chart of Example 1.

[0034] Figure 2 It is the holographic image of Example 1.

[0035] Figure 3 It is the luminescent image of Examples 1 to 3 under ultraviolet light. Detailed Embodiments

[0036] In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0037] The present invention provides an organometallic complex having one of the Pt-1 and Pt-2 structures shown below:

[0038]

[0039] Wherein, R 1 is hydrogen, methyl, ethyl, trifluoromethyl, nitro, amino or phenyl; R 2 and R 3 are each independently hydrogen or cyano; R 4 is n-octyl, n-octyloxy, isooctyl, isooctyloxy, n-dodecyl, n-dodecyloxy, n-hexadecyl, n-hexadecyloxy, tetraethylene glycol or citronellyl; n is 0 or 1; p is 0 or 1; m is any integer from 1 to 5.

[0040] The present invention also provides a dual-image storage material based on the above-mentioned organometallic complex with luminescent color as encrypted information, which is prepared by orthogonal photoreaction from 0.1 to 10 parts by weight of the above-mentioned organometallic complex, 20 to 75 parts by weight of a polymer binder, 20 to 75 parts of a photopolymerizable monomer, and 0.1 to 5 parts by weight of a photoinitiator. It can display a holographic image visible to the naked eye under natural light, present a luminescent image under ultraviolet light, and the color of the luminescent image can be precisely regulated by changing the content of the organometallic complex or the type of the polymer binder. This storage material has the dual-image anti-counterfeiting function of a luminescent image with adjustable luminescent color and a holographic image, which can improve the safety level of products.

[0041] In some embodiments, the preparation method of the above dual-image storage material includes the following preparation steps:

[0042] (1) Dissolve each component of the dual-image storage material in an organic solvent to obtain a uniform mixed solution;

[0043] (2) Coating and laminating the uniform mixed solution obtained in step (1) to obtain a uniform holographic photosensitive film, and irradiating it with coherent laser light to cause the photopolymerizable monomer to undergo free radical polymerization, obtaining a holographic material storing a holographic image; among them, the holographic exposure includes two methods, which are the interference of two coherent laser beams on both sides of the photosensitive film or the interference of a single laser beam with a reflector inside the photosensitive film to generate a grating structure through photopolymerization;

[0044] (3) Post-cure the holographic material obtained in step (2) with white light to completely react the unreacted photopolymerizable monomer, fix the holographic image, and at the same time bleach the photosensitizer to prevent its luminescence from interfering with the luminescence of the organometallic complex;

[0045] (4) Irradiate the holographic material obtained in step (3) with ultraviolet light through a mask plate. The organometallic complex in the irradiated area undergoes a double bond cycloaddition reaction, and its luminescence changes, showing a significant contrast with the unirradiated area, realizing the storage of the luminescent image, that is, obtaining a dual-image storage material storing a holographic image and a luminescent image.

[0046] The present invention designs a class of organometallic complexes that have good compatibility with the holographic composite system and do not reduce the holographic image storage quality. The luminescent images prepared by the photoreaction of the organometallic complexes can have their luminescent colors after photoreaction regulated by controlling the content of the organometallic luminescent materials. Experiments have found that the intermolecular interaction forces of the organometallic complexes of the present invention will affect their luminescent colors. The stronger the intermolecular interaction forces, the more red-shifted the luminescence. In the dual-image storage material described in the present invention, the image storage material without ultraviolet light irradiation exhibits red luminescence. Although the content of the organometallic complexes is different, the luminescent colors of the image storage materials are all red, indicating that the intermolecular interaction forces of the organometallic complexes are relatively strong, which is conducive to the occurrence of photochemical double-bond cycloaddition reactions. After ultraviolet light irradiation, the double-bond cycloaddition reaction occurs in the organometallic complexes in the irradiated area, and the intermolecular interaction forces between the photoreaction product molecules change; as the content of the organometallic complexes increases, the intermolecular interaction forces between the photoreaction product molecules increase, and the luminescence in the irradiated area is red-shifted, and the luminescent color changes. When the content of the organometallic complexes is fixed and the type of the polymer binder is changed, the color of the luminescent image can also be regulated. It may be because the molecular packing states of the organometallic complexes in different polymer binders are different, resulting in different intermolecular interaction forces between the photoreaction product molecules, manifested as different luminescence. The multiple luminescence regulation characteristics exhibited by this single luminescent material in the composite material help to improve the anti-counterfeiting performance.

[0047] The holographic image can be directly observed through the reflected light. When at the optimal viewing angle, i.e., the Bragg angle, the wavelength of the reflected color of the holographic image is around the recording wavelength. For example, if the recording wavelength is green light of 532 nm, the reflected color at the optimal angle is also green.

[0048] The luminescent image can be observed under ultraviolet light with an intensity less than 1 mW / cm².

[0049] The holographic performance of the image storage material of the present invention is described by the diffraction efficiency. The specific test method is as follows: Use a UV-visible spectrophotometer to measure the transmittance of the dual-image storage material in the wavelength range of 400 - 750 nm;

[0050] The diffraction efficiency η is calculated by the following formula:

[0051]

[0052] where T V and T b and are the transmittance of the dual-image storage material at the Bragg wavelength and the transmittance of the baseline at the corresponding wavelength, respectively, as shown in the appendix Figure 1 shown.

[0053] The dual-image storage material provided by the present invention has excellent anti-counterfeiting performance and is convenient for rapid identification.

[0054] The following are examples:

[0055] Example 1

[0056] The dual - image storage material provided by the present invention is prepared by orthogonal photoreaction from 0.5 parts by weight of Pt - 1 (R 1 is hydrogen, R 2 is hydrogen, R 3 is cyano group, R 4 is isooctyloxy, n is 1, p is 1, m is 3), 50 parts by weight of polyethyl methacrylate, 46.5 parts by weight of ethoxyphenol acrylate, and 3 parts by weight of sodium tetraiodotetrachlorofluorescein, triethanolamine, and chlorodiphenyliodonium salt.

[0057] The preparation method of this dual - image storage material is as follows:

[0058] First, dissolve Pt - 1 (R 1 is hydrogen, R 2 is hydrogen, R 3 is cyano group, R 4 is isooctyloxy, n is 1, p is 1, m is 3), polyethyl methacrylate, ethoxyphenol acrylate, sodium tetraiodotetrachlorofluorescein, triethanolamine, and chlorodiphenyliodonium salt in a mixed solvent of dichloromethane and methanol, and stir until a homogeneous and transparent solution is obtained.

[0059] Coat the obtained homogeneous and transparent solution through a 100 - micron applicator, then cover it with a PET film to obtain a uniform holographic photosensitive film. Place it under coherent laser irradiation at 532 nm to cause free - radical polymerization of the photopolymerizable monomer, and a holographic material storing a holographic image is obtained. Place the holographic material with the holographic image under a white light belt to bleach the photosensitizer and fix the holographic image. Subsequently, irradiate it with ultraviolet light using a mask plate, irradiate it with ultraviolet light at 300 nm and a light intensity of 20 mW / cm² for 10 minutes, and a dual - image storage material storing holographic images and blue - light emitting images as shown in Figure 2 and Figure 3 is obtained.

[0060] Example 2

[0061] The dual - image storage material provided by the present invention is prepared by orthogonal photoreaction from 3 parts by weight of Pt - 1 (R 1 is hydrogen, R 2 is hydrogen, R 3 is cyano group, R 4 is isooctyloxy, n is 1, p is 1, m is 3), 50 parts by weight of polyethyl methacrylate, 44 parts by weight of ethoxyphenol acrylate, and 3 parts by weight of sodium tetraiodotetrachlorofluorescein, triethanolamine, and chlorodiphenyliodonium salt.

[0062] The preparation method of this dual-image storage material is as follows:

[0063] First, dissolve Pt-1 (where R 1 is hydrogen, R 2 is hydrogen, R 3 is cyano group, R 4 is isooctyloxy group, n is 1, p is 1, m is 3), polymethyl methacrylate, ethoxyphenol acrylate, sodium tetraiodotetrachlorofluorescein, triethanolamine, and chlorodiphenyliodonium salt in a mixed solvent of dichloromethane and methanol, and stir until a homogeneous transparent solution is obtained.

[0064] Coat the obtained homogeneous transparent solution with a 100-micron applicator, then cover it with a PET film to obtain a uniform holographic photosensitive film. Place it under the irradiation of a 532-nm coherent laser to cause the free radical polymerization of the photopolymerizable monomer, and a holographic material storing a holographic image is obtained. Place the holographic material with the holographic image under a white light band to bleach the photosensitizer and fix the holographic image. Subsequently, irradiate it with ultraviolet light through a mask, and irradiate it with ultraviolet light at 300 nm and a light intensity of 20 mW / cm² for 12 minutes to obtain a dual-image storage material that stores both a holographic image and Figure 3 the green light-emitting image shown.

[0065] Example 3

[0066] The dual-image storage material provided by the present invention is prepared by an orthogonal photoreaction from 8 parts by weight of Pt-1 (where R 1 is hydrogen, R 2 is hydrogen, R 3 is cyano group, R 4 is isooctyloxy group, n is 1, p is 1, m is 3), 50 parts by weight of polymethyl methacrylate, 39 parts by weight of ethoxyphenol acrylate, and 3 parts by weight of sodium tetraiodotetrachlorofluorescein, triethanolamine, and chlorodiphenyliodonium salt.

[0067] The preparation method of this dual-image storage material is as follows:

[0068] First, dissolve Pt-1 (where R 1 is hydrogen, R 2 is hydrogen, R 3 is cyano group, R 4 is isooctyloxy group, n is 1, p is 1, m is 3), polymethyl methacrylate, ethoxyphenol acrylate, sodium tetraiodotetrachlorofluorescein, triethanolamine, and chlorodiphenyliodonium salt in a mixed solvent of dichloromethane and methanol, and stir until a homogeneous transparent solution is obtained.

[0069] The obtained uniform and transparent solution was coated with a 100-μm applicator, and then covered with a PET film to obtain a uniform holographic photosensitive film. The film was irradiated with coherent laser light at 532 nm to cause free radical polymerization of the photopolymerizable monomer, resulting in a holographic material storing a holographic image. The holographic material with the holographic image was placed under a white light band to bleach the photosensitizer and fix the holographic image. Subsequently, it was irradiated with ultraviolet light using a mask plate. Ultraviolet light with a wavelength of 300 nm and an intensity of 20 mW / cm² was used to irradiate for 15 minutes, obtaining a dual-image storage material that simultaneously stores a holographic image and Figure 3 the yellow light-emitting image shown in

[0070] Examples 1 to 3 are all dual-image storage materials with polymethacrylate as the polymer binder. The difference is that the content of the organometallic complex is different. As the content of the organometallic complex gradually increases within a large range, the color of the light-emitting image after complete reaction with ultraviolet light for different times redshifts from blue to yellow. In addition, the diffraction efficiency of the holographic images of the dual-image storage materials in Examples 1 to 3 is greater than 90%, and the holographic images have high brightness and significant contrast.

[0071] Example 4

[0072] The dual-image storage material provided by the present invention is prepared by an orthogonal photoreaction from 0.5 parts by weight of Pt-1 (R 1 is hydrogen, R 2 is hydrogen, R 3 is cyano, R 4 is isooctyloxy, n is 1, p is 1, m is 3), 50 parts by weight of polystyrene, 46.5 parts by weight of ethoxyphenol acrylate, and 3 parts by weight of sodium tetraiodotetrachlorofluorescein, triethanolamine, and chlorodiphenyl iodonium salt.

[0073] The preparation method of this dual-image storage material is as follows:

[0074] First, Pt-1 (R 1 is hydrogen, R 2 is hydrogen, R 3 is cyano, R 4 is isooctyloxy, n is 1, p is 1, m is 3), polystyrene, ethoxyphenol acrylate, sodium tetraiodotetrachlorofluorescein, triethanolamine, and chlorodiphenyl iodonium salt were dissolved in a mixed solvent of dichloromethane and methanol, and stirred until a uniform and transparent solution was obtained.

[0075] The obtained uniform and transparent solution was coated with a 100-μm applicator, and then covered with a PET film to obtain a uniform holographic photosensitive film. The film was irradiated with coherent laser light at 532 nm to cause free radical polymerization of the photopolymerizable monomers, resulting in a holographic material storing a holographic image. The holographic material with the holographic image was placed under a white light band to bleach the photosensitizer and fix the holographic image. Subsequently, it was irradiated with ultraviolet light using a mask plate, with ultraviolet light at 300 nm and an intensity of 20 mW / cm² for 10 minutes.

[0076] The luminescent image of the dual-image storage material in Example 4 had a weak brightness and a blue luminescent color. The diffraction efficiency of the holographic image was relatively low, at 45%. The possible reason is that the interaction force between polystyrene as a polymer binder and the monomers is relatively large, which has a greater impact on the diffusion of the monomers during the holographic photoreaction, resulting in poor regularity of the holographic grating and a reduction in the diffraction efficiency.

[0077] Example 5

[0078] The dual-image storage material provided by the present invention is prepared by an orthogonal photoreaction from 3 parts by weight of Pt-1 (R 1 is hydrogen, R 2 is hydrogen, R 3 is cyano, R 4 is isooctyloxy, n is 1, p is 1, m is 3), 50 parts by weight of polystyrene, 45 parts by weight of ethoxyphenol acrylate, and 3 parts by weight of sodium tetraiodotetrachlorofluorescein, triethanolamine, and chlorodiphenyliodonium salt.

[0079] The preparation method of this dual-image storage material is as follows:

[0080] First, Pt-1 (R 1 is hydrogen, R 2 is hydrogen, R 3 is cyano, R 4 is isooctyloxy, n is 1, p is 1, m is 3), polyvinyl chloride, ethoxyphenol acrylate, sodium tetraiodotetrachlorofluorescein, triethanolamine, and chlorodiphenyliodonium salt were dissolved in a mixed solvent of dichloromethane and methanol, and stirred until a uniform and transparent solution was obtained.

[0081] The obtained uniform and transparent solution was coated with a 100-μm applicator, and then covered with a PET film to obtain a uniform holographic photosensitive film. The film was irradiated with coherent laser light at 532 nm to cause free radical polymerization of the photopolymerizable monomers, resulting in a holographic material storing a holographic image. The holographic material with the holographic image was placed under a white light band to bleach the photosensitizer and fix the holographic image. Subsequently, it was irradiated with ultraviolet light using a mask plate, with ultraviolet light at 300 nm and an intensity of 20 mW / cm² for 15 minutes. A dual-image storage material storing both a holographic image and a yellow luminescent image was obtained.

[0082] Example 5 is different from Example 4 in that the content of the organometallic complex is different. In the dual-image storage material with polystyrene as the polymer binder, when the content of the organometallic complex increases to 2 weight fractions, the color of the luminescent image has redshifted to yellow. Comparing Examples 4 and 5 with Examples 1 to 3 shows that the dual-image storage materials of Examples 1 to 3 with polymethacrylate as the binder can regulate the color of the luminescent image in a wider range, and the diffraction efficiency of their holographic images is higher.

[0083] Example 6

[0084] The dual-image storage material provided by the present invention is prepared by orthogonal photoreaction from 4 parts by weight of Pt-1 (R 1 is hydrogen, R 2 is hydrogen, R 3 is cyano, R 4 is dodecyloxy, n is 1, p is 1, m is 1), 43 parts by weight of polymethacrylate, 50 parts by weight of ethoxyphenol acrylate, and 3 parts by weight of sodium tetraiodotetrachlorofluorescein, triethanolamine, and chlorodiphenyliodonium salt.

[0085] The preparation method of this dual-image storage material is as follows:

[0086] First, dissolve Pt-1 (R 1 is hydrogen, R 2 is hydrogen, R 3 is cyano, R 4 is n-octyl, n is 1, p is 1, m is 3), polyvinyl chloride, ethoxyphenol acrylate, sodium tetraiodotetrachlorofluorescein, triethanolamine, and chlorodiphenyliodonium salt in a mixed solvent of dichloromethane and methanol. After stirring, it is found that it is difficult for the organometallic complex to completely dissolve to obtain a uniform and transparent solution. The reason is that the type and number m of the side chain R 4 of the organometallic complex affect its solubility.

[0087] The following table shows the formulations involved in other typical embodiments of the present invention. However, the embodiments of the present invention are not limited thereto, and all can be realized within the scope protected by the present invention.

[0088] Table 1: Formulations Involved in Other Typical Embodiments of the Present Invention

[0089]

[0090] Table 2: Specific Structures of Organometallic Complexes in Examples 7 to 23 of the Present Invention

[0091]

[0092]

[0093] Table 3: Other components of the image storage materials in Examples 7 to 23

[0094]

[0095]

[0096]

[0097] Table 4: Coherent laser parameter conditions during the preparation of the image storage materials in Examples 7 to 23

[0098]

[0099] Table 5: UV light parameter conditions during the preparation of the image storage materials in Examples 7 to 23

[0100]

[0101] Table 6: Diffraction efficiency of the holographic images and colors of the luminescent images in Examples 1 to 23

[0102]

[0103]

[0104] As can be seen from Tables 1 to 6, in Examples 1 to 3 and 7 to 14, the dual-image storage materials with polymethyl methacrylate, polyethyl methacrylate, polybutyl methacrylate, polyisobutyl methacrylate, glycidyl methacrylate, poly(methyl methacrylate-co-ethyl acrylate), and polyvinyl acetate as the polymer binders can regulate the color of the luminescent image within a wide range by controlling the content of the organometallic complex. In the dual-image storage materials with polystyrene or polyvinyl chloride as the polymer binder in Examples 4 to 5 and 15 to 18, when the content of the organometallic complex is small, the color of the luminescent image has been fixed and cannot be regulated by further increasing the content of the organometallic complex. In Examples 2 and 5, when the content of the organometallic complex is the same, different types of polymer binders can also result in different colors of the luminescent image. It can be seen from the above examples that the dual-image storage materials provided by the present invention can indeed regulate the color of the luminescent image within a wide range by controlling the content of the organometallic complex and / or the type of the polymer binder, realizing multiple security anti-counterfeiting functions.

[0105] For the image storage materials prepared in Examples 22 and 23 in Table 6, there is no data on their diffraction efficiency and luminescent color, probably because the organometallic complex used has poor solubility, resulting in the inability to form a homogeneous transparent solution and thus unable to prepare the dual-image storage materials.

[0106] Those skilled in the art can easily understand that the above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. An organometallic complex, characterized in that, it has one of the Pt-1 and Pt-2 structures shown below: ， ， Among them, R 1 is hydrogen, methyl, ethyl, trifluoromethyl, nitro, amino or phenyl; R 2 and R 3 are each independently hydrogen or cyano; R 4 is n-octyl, n-octyloxy, isooctyl, isooctyloxy, n-dodecyl, n-dodecyloxy, n-hexadecyl, n-hexadecyloxy, tetraethylene glycol or citronellyl; m is any integer from 1 to 5; n is 0 or 1; p is 0 or 1.

2. The organometallic complex according to claim 1, characterized in that, R 4 is isooctyloxy or n - hexadecyloxy, and m is any integer from 3 to 5.

3. The organometallic complex according to claim 1, characterized in that, R 4 is a tetraethylene glycol group or a citronellol group, and m is any integer from 1 to 5.

4. A dual-image storage material with adjustable emission color, characterized in that, by weight, it is prepared by an orthogonal photoreaction from 0.1 to 10 parts of the organometallic complex according to any one of claims 1 to 3, 20 to 75 parts of a polymer binder, 20 to 75 parts of a photopolymerizable monomer, and 0.1 to 5 parts of a photoinitiator; When in use, the image storage material uses the emission color as encrypted information, and it can display a holographic image visible to the naked eye under natural light, present an emission image under ultraviolet light, and the color of the emission image can be adjusted by changing the content of the organometallic complex and / or the type of the polymer binder.

5. The dual-image storage material according to claim 4, characterized in that, the refractive index of the polymer binder is less than 1.5, specifically at least one of polymethyl methacrylate, polyethyl methacrylate, polybutyl methacrylate, polyisobutyl methacrylate, glycidyl methacrylate, poly(methyl methacrylate-co-ethyl acrylate), polyvinyl acetate, polystyrene, and polyvinyl chloride.

6. The dual-image storage material according to claim 4, characterized in that, the refractive index of the photopolymerizable monomer is greater than 1.5, specifically at least one of ethoxyphenyl acrylate, o-phenylphenylethoxy acrylate, 2-phenylethyl acrylate, 2-phenoxyethyl acrylate, 2-[4-(1-methyl-1-phenylethyl)phenoxy]ethyl acrylate, 2-naphthyl acrylate, and 2-(1-naphthyloxy)ethyl acrylate.

7. The dual-image storage material according to claim 4, characterized in that, the photoinitiator includes a photosensitizer and a co-initiator, the photosensitizer is at least one of 3,3'-carbonylbis(7-diethylaminocoumarin), Irgacure784, sodium tetraiodotetrachlorofluorescein, methylene blue, new methylene blue, safranin O, and eosin Y; the co-initiator is one or several of triethanolamine, triisopropanolamine, methyldiethanolamine, chlorodiphenyliodonium salt, and diphenyliodonium hexafluorophosphate.

8. A preparation method of the dual-image storage material according to any one of claims 4 to 7, characterized in that, it includes the following steps: (1) Dissolve the components of the dual-image storage material in an organic solvent to obtain a uniformly mixed solution; (2) Prepare a holographic photosensitive film by coating and solvent evaporation of the uniformly mixed solution obtained in step (1), and then expose it under coherent laser light to obtain a holographic material storing a holographic image through the polymerization reaction of the photopolymerizable monomer; (3) Post-cure the holographic material obtained in step (2) with white light to further react the unreacted photopolymerizable monomer and fix the holographic image to obtain a holographic material after fixing the holographic image; (4) Place the holographic material after fixing the holographic image described in step (3) under a mask plate, irradiate it with ultraviolet light, and store a luminescent image through the double-bond cycloaddition reaction of the organometallic complex to obtain a dual-image storage material that stores both the holographic image and the luminescent image.

9. The preparation method according to claim 8, characterized in that the wavelength of the coherent laser described in step (2) is one of 460 nm, 532 nm or 640 nm, the light intensity is 0.1 - 5 mW / cm², and the exposure time is 5 - 120 seconds; the wavelength of the ultraviolet light described in step (4) is 200 - 380 nm, the light intensity is 5 - 200 mW / cm², and the irradiation time is 1 - 30 minutes.

10. Application of the dual-image storage material according to any one of claims 4 to 7 in the field of anti-counterfeiting.

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