Photosensitive fluorescent polyurethane material, and preparation method and application thereof

Abstract

The application discloses a photosensitive fluorescent polyurethane material and a preparation method and application thereof, and belongs to the technical field of optical anti-counterfeiting material preparation. The photosensitive fluorescent polyurethane material disclosed by the application integrates photosensitive patterning and fluorescence into one, has wide environmental adaptability, supports large-scale continuous preparation, can efficiently produce large-area holographic color patterns through mask exposure technology, meets the anti-counterfeiting demand in complex scenes, and significantly reduces production cost and improves product competitiveness due to low-cost manufacturing process and high-value-added anti-counterfeiting characteristics, thereby providing an innovative solution for the packaging anti-counterfeiting field.

Description

Technical Field

[0001] This invention belongs to the field of optical anti-counterfeiting material preparation technology, and in particular relates to a photosensitive fluorescent polyurethane material, its preparation method and application. Background Technology

[0002] Current anti-counterfeiting materials are generally limited by the industry's predicament of being easily counterfeited due to their single identification mode. Traditional fluorescent anti-counterfeiting relies on static luminescence characteristics, which can be easily cracked through spectral analysis. Although physical structural color anti-counterfeiting has unique optical effects, it is difficult to achieve dynamic response. When existing technologies integrate fluorescent and photosensitive components through physical blending, performance deterioration often occurs due to phase separation, and the function only achieves mechanical superposition without producing synergistic effects.

[0003] Therefore, there is an urgent need in this field to develop a new type of anti-counterfeiting material that can overcome functional barriers. Summary of the Invention

[0004] To address the problem that current anti-counterfeiting materials are generally limited by a single identification mode and are easily counterfeited, this invention provides a photosensitive fluorescent polyurethane material, its preparation method, and its applications. This invention innovatively integrates photosensitive and fluorescent groups into the polyurethane backbone through molecular design, constructing a dynamic multimodal anti-counterfeiting system. Under ultraviolet light triggering, this material simultaneously achieves multiple anti-counterfeiting mechanisms: the photosensitive group forms a periodic grating on the surface through photoinduced light, generating rainbow structural colors through Bragg diffraction; the fluorescent group emits high-intensity characteristic blue-cyan fluorescence under ultraviolet light; the key lies in the molecular-level synergistic effect of the two groups, causing the fluorescence emission intensity and wavelength to evolve in real time with ultraviolet irradiation conditions, forming a unique dynamic optical anti-counterfeiting mode.

[0005] A photosensitive fluorescent polyurethane material, with the following chemical structural formula:

[0006] ;

[0007] Wherein, structural unit A is an alkyl or aryl structure containing at least two isocyanate groups; structural unit B is an aryl structure containing at least two hydroxyl or amino groups, which is connected to the photosensitive group by an ether bond through an alkane chain; and structural unit C is an alkyl or aryl structure containing at least two hydroxyl groups.

[0008] Where x∶(y+z) is 1∶(1-99)

[0009] The photosensitive fluorescent polyurethane material of this invention is formed by copolymerization of photosensitive monomers, fluorescent monomers, and polymers. The photosensitive groups introduced into the photosensitive fluorescent polyurethane material endow the polyurethane with excellent photoresponse properties. Under ultraviolet light irradiation, the surface of this material can undergo a photoreaction, forming a grating structure. This structure, under white light, produces significant structural colors through the Bragg diffraction effect, exhibiting a rainbow pattern. Simultaneously, the fluorescent groups introduced into the photosensitive fluorescent polyurethane material can emit strong blue-cyan fluorescence under ultraviolet light excitation. There is a synergistic effect between the photosensitive groups and the fluorescent groups, causing the emission behavior (including emission intensity and wavelength) of the fluorescent groups to change with ultraviolet light irradiation conditions.

[0010] A method for preparing the above-mentioned photosensitive fluorescent polyurethane material includes the following steps: under the protection of an inert gas, a diisocyanate monomer having structural unit A and a photosensitive diamine or diol monomer having structural unit B are added to an organic solvent, and the mixture is stirred and reacted in an ice-water bath at 0-5°C (first reaction); then, a diamine or diol monomer having structural unit C, a tetraphenylethylene monomer containing two amino groups (i.e., a fluorescent group monomer), and a catalyst are added sequentially, and the mixture is stirred and reacted again (second reaction) to obtain a photosensitive fluorescent polyurethane solution; the photosensitive fluorescent polyurethane solution is coated onto a substrate, and then transferred to a vacuum oven and dried at 50-100°C for 30-120 min to obtain the photosensitive fluorescent polyurethane material. The amount of the photosensitive diamine or diol monomer having structural unit B is 1-50% of the total amount of all monomers; the amount of the tetraphenylethylene monomer containing two amino groups is 1-10% of the total amount of all monomers.

[0011] Furthermore, the first reaction takes 2 hours; and / or the conditions for the second reaction are: reacting at room temperature for 7 hours, then heating to 40°C for 12 hours, and then further heating to 60°C for 3 hours.

[0012] Furthermore, the amount of catalyst added is 0.1-5% of the total mass of the monomer raw materials of the photosensitive fluorescent polyurethane material.

[0013] Furthermore, the organic solvent is selected from dichloromethane, dimethyl sulfoxide, sulfolane, N,N-dimethylformamide, N,N-dimethylacetamide or N-methylpyrrolidone, or any mixture of two or more of the above solvents in any proportion.

[0014] Application of the above-mentioned photosensitive fluorescent polyurethane material in the preparation of anti-counterfeiting labels with dual optical effect characteristics that are responsive to stimuli.

[0015] This invention also provides a method for preparing a stimulus-responsive anti-counterfeiting label with dual optical effects, comprising the following steps: preparing a self-supporting dry film or a substrate-supporting dry film of the photosensitive fluorescent polyurethane material using a photosensitive fluorescent polyurethane solution; subsequently fixing the self-supporting dry film or the substrate-supporting dry film under a UV-transparent photomask, exposing the self-supporting dry film or the substrate-supporting dry film to UV light through the UV-transparent photomask; after exposure, developing the self-supporting dry film or the substrate-supporting dry film, i.e., immersing it in an organic solvent and then drying it, thereby preparing a holographic color pattern on the surface of the self-supporting dry film or the substrate-supporting dry film, thus obtaining the stimulus-responsive anti-counterfeiting label with dual optical effects.

[0016] In the above preparation process, ultraviolet light irradiation triggers photochemical reactions of photosensitive groups, forming a grating concave-convex structure with a period of 0.1-10 μm and a height of 30-1000 nm on the surface of the self-supporting dry film or the substrate-supported dry film. This structure generates an angle-dependent rainbow pattern through the Bragg diffraction effect. The grating period is directly controlled by the mask pattern parameters, and the structure height is controlled by the exposure time and exposure amount.

[0017] The structural formula of the photosensitive group in the photosensitive fluorescent polyurethane material after ultraviolet light irradiation is as follows:

[0018] ;

[0019] Furthermore, the photosensitive fluorescent polyurethane solution is coated onto the substrate surface by casting or spin coating to form a wet film with a thickness of 5-500 μm. After removing the solvent by heating on a hot table, drying with a forced air or vacuum drying, a dry film is prepared.

[0020] Furthermore, the ultraviolet-transmitting mask has a grating structure, the exposure line width of the grating structure is 0.1-10μm, and the grating period is 0.1-10μm.

[0021] Furthermore, the wavelength of the ultraviolet light is 100-400nm.

[0022] Furthermore, the exposure time is 10-60 seconds, and the exposure dose is 50-250 mJ / cm². 2 .

[0023] Furthermore, the organic solvent is selected from methanol, ethanol, propanol, acetonitrile, acetone or petroleum ether, or any mixture of two or more of the above organic solvents in any proportion.

[0024] A stimulus-responsive anti-counterfeiting label with dual optical effect features prepared by the above preparation method.

[0025] Compared with the prior art, the present invention has the following advantages and technical effects:

[0026] The photosensitive fluorescent polyurethane material disclosed in this invention integrates photosensitive patterning and fluorescence functions, has wide environmental adaptability, supports large-scale continuous production, and can efficiently produce large-area holographic color patterns through mask exposure technology to meet the anti-counterfeiting needs of complex scenarios. Its low-cost manufacturing process and high-value-added anti-counterfeiting characteristics significantly reduce production costs and enhance product competitiveness, providing an innovative solution for the packaging anti-counterfeiting field.

[0027] This invention discloses a stimulus-responsive anti-counterfeiting label with dual optical effects, which can be formed into a highly stable transparent film that adapts to different environments through molecular structure design. Attached Figure Description

[0028] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0029] Figure 1 The chemical reaction formula for a method of synthesizing a photosensitive fluorescent polyurethane material provided in Example 1;

[0030] Figure 2 The pattern of the ultraviolet-transmitting photomask in Example 1;

[0031] Figure 3 An atomic force microscope image of the microscopic grating concave-convex structure in the stimulus-responsive anti-counterfeiting label with dual optical effect characteristics prepared in Example 1;

[0032] Figure 4 A graph showing the period and height data of the microscopic grating concave-convex structure in the stimulus-responsive anti-counterfeiting label with dual optical effects prepared in Example 1;

[0033] Figure 5 Trend graph of fluorescence emission spectrum of the stimulus-responsive anti-counterfeiting label with dual optical effect characteristics prepared in Example 1 under continuous ultraviolet light irradiation;

[0034] Figure 6 A digital photograph of the stimulus-responsive anti-counterfeiting label with dual optical effect features prepared in Example 1 under white light;

[0035] Figure 7 A digital photograph of the stimulus-responsive anti-counterfeiting label with dual optical effects prepared for Example 1 under ultraviolet light (365nm);

[0036] Figure 8The chemical reaction formula for a method of synthesizing a photosensitive fluorescent polyurethane material provided in Example 2;

[0037] Figure 9 The pattern of the ultraviolet-transmitting photomask in Example 2;

[0038] Figure 10 An atomic force microscope image of the microscopic grating concave-convex structure in the stimulus-responsive anti-counterfeiting label with dual optical effect characteristics prepared in Example 2;

[0039] Figure 11 The period and height data of the microscopic grating concave-convex structure in the stimulus-responsive anti-counterfeiting label with dual optical effect characteristics prepared in Example 2;

[0040] Figure 12 Trend graph of fluorescence emission spectrum of the stimulus-responsive anti-counterfeiting label with dual optical effect characteristics prepared in Example 2 under continuous ultraviolet light irradiation;

[0041] Figure 13 A digital photograph of the stimulus-responsive anti-counterfeiting label with dual optical effect features prepared in Example 2 under white light;

[0042] Figure 14 A digital photograph of the stimulus-responsive anti-counterfeiting label with dual optical effects prepared for Example 2 under ultraviolet light (365nm). Detailed Implementation

[0043] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0044] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Every smaller range between any stated value or intermediate value within a stated range, and any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0045] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0046] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be obvious to those skilled in the art. This application specification and embodiments are merely exemplary.

[0047] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0048] The room temperature in this invention refers to 25±2℃.

[0049] Example 1

[0050] The chemical reaction formula for a method of synthesizing a photosensitive fluorescent polyurethane material provided in this embodiment is as follows: Figure 1 As shown.

[0051] The specific preparation method of this photosensitive fluorescent polyurethane material is as follows:

[0052] 22.18 kg (327 mol) of benzidine containing a photosensitive group (as shown in the above formula) and 46.68 kg (209.96 mol) of isophorone diisocyanate (as shown in the above formula) were added to a reactor containing 189.60 kg of N,N-dimethylformamide (DMF) under anhydrous and inert gas (nitrogen) protection. The mixture was stirred and reacted in an ice-water bath at 0-5°C for 2 h. Then, 21.03 kg (177.96 mol) of 1,6-hexanediol (as shown in the above formula), 0.73 kg (2.014 mol) of 4-(2-(4-aminophenyl)-1,2-diphenylvinyl)aniline, and 0.08 kg of dibutyltin dilaurate catalyst were added sequentially to the reactor. After stirring at room temperature for 7 h, the reaction mixture was transferred to an oil bath and heated to 40°C for 12 h, and then further heated to 60°C for 3 h. The reaction was carried out for 24 hours. A photosensitive fluorescent polyurethane solution (where x∶(y+z) was 1∶9) was prepared by segmented heating. The obtained photosensitive fluorescent polyurethane solution was defoamed at room temperature in the dark. The photosensitive fluorescent polyurethane solution was then coated onto a coverslip that had been irradiated with dual-wavelength ultraviolet light at 185nm and 254nm for 15min by spin coating. The resulting photosensitive fluorescent polyurethane film was then transferred to a vacuum oven and baked at 100℃ for 90min to obtain a photosensitive fluorescent polyurethane dry film, i.e., the photosensitive fluorescent polyurethane material.

[0053] A stimulus-responsive anti-counterfeiting label with dual optical effects was prepared on the obtained photosensitive fluorescent polyurethane dry film. The specific preparation method is as follows:

[0054] The obtained photosensitive fluorescent polyurethane dry film was adhered tightly to the chromium surface of a UV-transparent photomask and fixed below the pattern on the photomask (which has a grating structure with an exposure line width of 3 μm and a grating period of 6 μm). It was then subjected to selective exposure under a 365 nm UV light source (exposure time 10 s, exposure dose 50 mJ / cm²). 2 After exposure, the photosensitive fluorescent polyurethane dry film is developed by immersing it in acetonitrile for 1 second and then drying it, thereby obtaining a holographic color pattern on the surface of the photosensitive fluorescent polyurethane dry film. This produces a stimulus-responsive anti-counterfeiting label with dual optical effects, wherein the pattern that is transparent to ultraviolet light is as follows: Figure 2 As shown.

[0055] Figure 3 An atomic force microscope image of the microscopic grating-like structure in the stimulus-responsive anti-counterfeiting label with dual optical effects prepared in Example 1. Figure 4 A graph showing the period and height data of the microscopic grating concave-convex structure in the stimulus-responsive anti-counterfeiting label with dual optical effects prepared in Example 1. Figure 3 and Figure 4 As can be seen, the period of the grating concave-convex structure is 6μm and the average height is 30nm. Under this structure, white light illumination causes Bragg diffraction, producing obvious rainbow patterns, and the pattern colors have a strong angle dependence.

[0056] The anti-counterfeiting label with dual optical effects prepared in Example 1 was continuously irradiated with ultraviolet light to investigate its dynamic fluorescence response characteristics. Specifically, 365nm ultraviolet light was used as the excitation source to continuously irradiate the sample, and the emission spectrum changes in the wavelength range of 400-600nm were systematically monitored to show the evolution of the emission peak intensity and peak position in the 400-600nm range under different irradiation times.

[0057] Figure 5 The trend diagram of the fluorescence emission spectrum of the stimulus-responsive anti-counterfeiting label with dual optical effects prepared in Example 1 under continuous ultraviolet light irradiation is shown below. Figure 5 As shown, the anti-counterfeiting label with dual optical effects prepared in this embodiment exhibits a strong blue-cyan fluorescence emission peak at 470 nm, and the intensity and wavelength of this peak show a regular change with increasing UV irradiation time. This phenomenon originates from the photochemical transformation of the 1,4-dihydropyridine structure in the photosensitive group, that is, it gradually transforms into the 2,6-dimethylpyridine structure under UV excitation. This molecular reconstruction process changes the absorption behavior of the fluorescent group to UV light, resulting in the coordinated evolution of the emission peak intensity and wavelength with irradiation time.

[0058] The color development characteristics of the anti-counterfeiting label with dual optical effects prepared in Example 1 were observed under white light. The experiment used a fixed camera position, with the sample placed on an adjustable tilt platform. By changing the tilt angle of the platform (range of 5.1°-10.8°), seven different color development states could be captured.

[0059] Figure 6 A digital photograph of the stimulus-responsive anti-counterfeiting label with dual optical effects prepared in Example 1 under white light; from Figure 6 As can be seen from the above, the anti-counterfeiting label with dual optical effect characteristics prepared in Example 1 exhibits a significant view-dependent rainbow effect under white light irradiation, and its color characteristics change with the viewing angle.

[0060] Figure 7 A digital photograph of the stimulus-responsive anti-counterfeiting label with dual optical effects prepared in Example 1 under ultraviolet light (365nm). Figure 7 As can be seen, under 365nm ultraviolet light excitation, the sample exhibits high-intensity blue-cyan fluorescence emission, and the intensity and wavelength of this fluorescence emission peak change regularly with the extension of ultraviolet irradiation time.

[0061] Example 2

[0062] The chemical reaction formula for a method of synthesizing a photosensitive fluorescent polyurethane material provided in this embodiment is as follows: Figure 8 As shown.

[0063] The specific preparation method of this photosensitive fluorescent polyurethane material is as follows:

[0064] 22.18 kg (327 mol) of benzidine containing a photosensitive group (as shown in the above formula) and 36.57 kg (209.98 mol) of toluene diisocyanate (as shown in the above formula) were added to a reactor containing 189.60 kg of N,N-dimethylformamide under anhydrous and inert gas protection. The mixture was stirred in an ice-water bath at 0-5°C for 2 h. Then, 21.03 kg (177.96 mol) of 1,6-hexanediol (as shown in the above formula), 0.73 kg (2.014 mol) of 4-(2-(4-aminophenyl)-1,2-diphenylvinyl)aniline, and 0.08 kg of dibutyltin dilaurate catalyst were added to the reactor sequentially. After stirring at room temperature for 7 h, the reaction mixture was transferred to an oil bath and heated to 40°C for 12 h. The temperature was then further increased to 60°C for 3 h. The photosensitive fluorescent polyurethane solution (where x∶(y+z) is 1∶9) was prepared by segmented heating over 24 hours. The obtained photosensitive fluorescent polyurethane solution was defoamed at room temperature in the dark. The photosensitive fluorescent polyurethane solution was then coated onto a coverslip that had been irradiated with dual-wavelength ultraviolet light at 185nm and 254nm for 15 minutes by spin coating. The resulting photosensitive fluorescent polyurethane film was then transferred to a vacuum oven and baked at 100℃ for 90 minutes to obtain a photosensitive fluorescent polyurethane dry film, i.e., the photosensitive fluorescent polyurethane material.

[0065] A stimulus-responsive anti-counterfeiting label with dual optical effects was prepared on the obtained photosensitive fluorescent polyurethane dry film. The specific preparation method is as follows:

[0066] The obtained photosensitive fluorescent polyurethane dry film was adhered tightly to the chromium surface of a UV-transparent photomask and fixed below the pattern on the photomask (which has a grating structure with an exposure line width of 2 μm and a grating period of 4 μm). It was then subjected to selective exposure under a 365 nm UV light source (exposure time 10 s, exposure dose 50 mJ / cm²). 2 After exposure, the photosensitive fluorescent polyurethane dry film is developed by immersing it in acetonitrile for 1 second and then drying it, thereby obtaining a holographic color pattern on the surface of the photosensitive fluorescent polyurethane dry film. This produces a stimulus-responsive anti-counterfeiting label with dual optical effects, wherein the pattern that is transparent to ultraviolet light is as follows: Figure 9 As shown.

[0067] Figure 10 An atomic force microscope image of the microscopic grating-like structure in the stimulus-responsive anti-counterfeiting label with dual optical effects prepared in Example 2. Figure 11 A graph showing the period and height data of the microscopic grating concave-convex structure in the stimulus-responsive anti-counterfeiting label with dual optical effects prepared in Example 2. Figure 10 and Figure 11As can be seen, the period of the grating concave-convex structure is 4μm, and the average height is 190nm.

[0068] The anti-counterfeiting label with stimulus-responsive dual optical effect characteristics prepared in Example 2 was subjected to continuous ultraviolet light irradiation to investigate its dynamic fluorescence response characteristics. Figure 12 The trend diagram of the fluorescence emission spectrum of the stimulus-responsive anti-counterfeiting label with dual optical effects prepared in Example 2 under continuous ultraviolet light irradiation is shown below. Figure 12 As shown: The anti-counterfeiting label with dual optical effects prepared in this embodiment exhibits a strong blue-cyan fluorescence emission peak at 470 nm, and the intensity and wavelength of this peak show a regular change with increasing UV irradiation time. This phenomenon originates from the photochemical transformation of the 1,4-dihydropyridine structure in the photosensitive group, that is, it gradually transforms into the 2,6-dimethylpyridine structure under UV excitation. This molecular reconstruction process changes the absorption behavior of the fluorescent group to UV light, resulting in the coordinated evolution of the emission peak intensity and wavelength with irradiation time.

[0069] Figure 13 A digital photograph of the stimulus-responsive anti-counterfeiting label with dual optical effects prepared in Example 2 under white light; from Figure 13 As can be seen from the above, the anti-counterfeiting label with dual optical effect characteristics prepared in Example 2 exhibits a significant view-dependent rainbow effect under white light irradiation, and its color characteristics change with the observation angle.

[0070] Figure 14 A digital photograph of the stimulus-responsive anti-counterfeiting label with dual optical effects prepared in Example 2 under ultraviolet light (365nm). Figure 14 As can be seen, under 365nm ultraviolet light excitation, the sample exhibits high-intensity blue-cyan fluorescence emission, and the intensity and wavelength of this fluorescence emission peak change regularly with the extension of ultraviolet irradiation time.

[0071] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A photosensitive fluorescent polyurethane material, characterized in that, The chemical structural formula is: ； Wherein, the monomer corresponding to structural unit A is an alkyl or aryl structure containing two isocyanate groups; the monomer corresponding to structural unit C is an alkyl or aryl structure containing two hydroxyl groups; wherein, x∶(y+z) is 1∶(1-99), and n=4.

2. A method for preparing the photosensitive fluorescent polyurethane material according to claim 1, characterized in that, Includes the following steps: Under the protection of an inert gas, a diisocyanate monomer having structural unit A and a photosensitive diamine monomer are added to an organic solvent and stirred in an ice-water bath to carry out a first reaction; then a diol monomer having structural unit C, a tetraphenylethylene monomer containing two amino groups, and a catalyst are added sequentially, and stirring is continued to carry out a second reaction to obtain a photosensitive fluorescent polyurethane solution; the photosensitive fluorescent polyurethane solution is coated on a substrate and vacuum dried to prepare the photosensitive fluorescent polyurethane material.

3. The preparation method according to claim 2, characterized in that, The amount of catalyst added is 0.1-5% of the total mass of the monomer raw materials of the photosensitive fluorescent polyurethane material.

4. The preparation method according to claim 2, characterized in that, The first reaction takes 2 hours; and / or the second reaction is carried out under the following conditions: after reacting at room temperature for 7 hours, the temperature is raised to 40°C and reacted for 12 hours, and then the temperature is raised to 60°C and reacted for 3 hours.

5. The application of the photosensitive fluorescent polyurethane material of claim 1 in the preparation of anti-counterfeiting labels with stimuli-responsive dual optical effect characteristics.

6. A method for preparing a stimulus-responsive anti-counterfeiting label with dual optical effect characteristics, characterized in that, Includes the following steps: Prepare a self-supporting dry film or a substrate-supported dry film of the photosensitive fluorescent polyurethane material according to claim 1; The self-supporting dry film or the substrate-supporting dry film is exposed by ultraviolet light through a UV-transmitting mask. After exposure, the self-supporting dry film or the substrate-supporting dry film is developed, and a holographic color pattern is prepared on the surface of the self-supporting dry film or the substrate-supporting dry film to obtain the anti-counterfeiting label with dual optical effect characteristics that is responsive to stimulation.

7. The preparation method according to claim 6, characterized in that, The ultraviolet-transmitting mask has a grating structure, the exposure line width of the grating structure is 0.1-10μm, and the grating period is 0.1-10μm.

8. The preparation method according to claim 6, characterized in that, The wavelength of the ultraviolet light is 100-400nm.

9. The preparation method according to claim 6, characterized in that, The exposure time is 10-60 seconds, and the exposure intensity is 50-250 mJ / cm². 2 .

10. A stimulus-responsive anti-counterfeiting label with dual optical effect features prepared by the preparation method according to any one of claims 6-9.

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