Photosensitive monomer, photosensitive polyurethane and preparation method and application thereof

Abstract

The application relates to the technical field of photosensitive polymer synthesis, and discloses a photosensitive monomer, a photosensitive polyurethane and a preparation method and application thereof. The photosensitive monomer is prepared by reacting 5-hydroxy-2-nitrobenzaldehyde with a compound M and a compound N capable of accepting external electrons in a first polar solvent. The photosensitive monomer has high crosslinking activity, can be combined with isocyanate to synthesize polyurethane holographic polymer materials, and can endow the polyurethane holographic polymer materials with physical crosslinking photoisomerization performance. The pyridine structure generated under ultraviolet irradiation can not only form intermolecular hydrogen bonds with hydrogen-containing structures in the molecular chain to realize reversible crosslinking, but also can produce complexation with metal ions. The photosensitive monomer can widen the selection range of photosensitive monomers required for the production of holographic polymer materials, and effectively promote the development of holography. The photosensitive monomer has simple synthesis process, high yield, easy separation of products, high controllability, and can realize low-cost continuous production.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of photosensitive polymer synthesis, in particular to a photosensitive monomer, a photosensitive polyurethane and a preparation method and application thereof. BACKGROUND

[0002] With the rapid development of science and technology and the advent of the information age, information security problems are increasingly prominent, especially in the fields of currency, certificates, and commodities, the demand for anti-counterfeiting technology is constantly upgrading. Traditional anti-counterfeiting methods, such as watermarks and gold stamping, have played a role in anti-counterfeiting to some extent, but have problems such as being easily counterfeited and being difficult to identify on a large scale.

[0003] Using holographic materials as anti-counterfeiting encryption materials is a safe and efficient encryption method. Holographic materials include inorganic holographic materials and organic holographic materials, wherein the organic holographic material is prepared by reacting a polymer matrix, a photosensitive monomer, and a photoinitiator.

[0004] The existing organic holographic material usually uses a photosensitive monomer composed of an aromatic photosensitive structural unit, a co-initiator nitro structural unit, and a hydroxyl active structural unit, which can reduce the migration and volatility of the photoinitiator and improve the photoinitiation efficiency and photocuring efficiency. However, the stability of the photosensitive monomer is poor, it is easily initiated by light and heat to cause irreversible crosslinking and failure, resulting in low synthesis yield and inability to ensure performance and safety in different application scenarios, and the application effect in anti-counterfeiting and encryption polymer materials is poor. At the same time, the organic holographic material needs to introduce free radical type photosensitive monomers and photoinitiators and other light reaction components, and the preparation process needs to control the selective photopolymerization reaction of the free radical type photosensitive monomer, which has a complex preparation process, high cost, low controllability, and is not environmentally friendly, which is not conducive to industrial production and greatly limits its application in optical anti-counterfeiting and decoration.

[0005] It is urgent to develop an organic holographic material with simple preparation process, good controllability, and good anti-counterfeiting and encryption effect. SUMMARY

[0006] The present application provides a photosensitive monomer, a photosensitive polyurethane and a preparation method and application thereof, which aims to solve the problems of complex preparation process, poor controllability, and poor orientation encryption effect of the existing organic holographic material.

[0007] In order to achieve the above purpose, the following technical solutions are adopted.

[0008] In a first aspect of the present application, a photosensitive monomer is provided, and the chemical structure is shown as formula (1):

[0009]

[0010] Preferably, the photosensitive monomer is prepared by reacting 5-hydroxy-2-nitrobenzaldehyde with compound M and compound N of an acceptable external electron pair in a first polar solvent;

[0011] The chemical structure of the compound M is shown in formula (2):

[0012]

[0013] wherein R is selected from CH3, C2H5, CH(CH3)2, CH2CH2OCH3 or CH2CH(CH3)2;

[0014] The compound N is a Lewis acid or a Bronsted acid;

[0015] The first polar solvent includes any one of ethanol, acetic acid, tetrahydrofuran, methanol, trifluoroethanol, acetone, butanone, pyridine, acetonitrile or dichloromethane.

[0016] Preferably, the molar ratio of the 5-hydroxy-2-nitrobenzaldehyde, the compound M and the compound N is 1:2:5; the amount of the first polar solvent is at least 3 times of the total mass of the 5-hydroxy-2-nitrobenzaldehyde, the compound M and the compound N.

[0017] The temperature of the reaction is 0-15℃.

[0018] In the second aspect of the present application, a photosensitive polyurethane is provided, and the chemical structure thereof includes any one of general formula (3)-(5):

[0019]

[0020] R1 is selected from one of the following structural formulae:

[0021] R2 is selected from one of the following structural formulae:

[0022]

[0023] R3 is selected from

[0024] wherein n and m are the polymerization degree, 1≤n≤20; 10≤m≤30.

[0025] In the third aspect of the present application, a preparation method of the photosensitive polyurethane is provided, and the method includes:

[0026] The diisocyanate, the chain extender and the soft segment are dissolved in a second polar solvent, and the reaction is carried out in an inert atmosphere in an ice bath to obtain an intermediate solution;

[0027] The photosensitive monomer solution dissolved by the second polar solvent is added into the intermediate solution, and the reaction is carried out at 35-45℃ and then at 55-65℃, to obtain the photosensitive polyurethane.

[0028] Preferably, the molar ratio of the photosensitive monomer, the diisocyanate, the chain extender and the soft segment is 1:7.2:5:(0-3.6).

[0029] The amount of the second polar solvent is at least 2 times the total amount of the photosensitive monomer, the diisocyanate, the chain extender and the soft segment.

[0030] Preferably, the diisocyanate includes toluene diisocyanate or isophorone diisocyanate.

[0031] The chain extender is an amine chain extender or an alcohol chain extender; the alcohol chain extender includes any one of 1,4-butanediol (BDO), 1,6-hexanediol or glycerol; the amine chain extender includes ethylenediamine (DA) or N,N-dihydroxy(diisopropyl)aniline.

[0032] The soft segment includes a polyester or a polyether having at least two -OH / -NH2 functional groups.

[0033] The second polar solvent includes at least one of chloroform, dichloromethane, butyrolactone, butyl acetate, acetone, cyclopentanone, cyclohexanone, benzene, toluene, xylene, dioxane, dimethyl sulfoxide, sulfolane, N,N-dimethylformamide, N,N-dimethylacetamide, N-methyl-2-pyrrolidone or N-vinyl-2-pyrrolidone.

[0034] In another aspect of the present application, the photosensitive monomer or the photosensitive polyurethane is applied to the anti-counterfeiting encryption polymer material.

[0035] In another aspect of the present application, a holographic polymer material is provided, which includes the photosensitive monomer or the photosensitive polyurethane.

[0036] In another aspect of the present application, a preparation method of the holographic polymer material is provided, which includes:

[0037] The photosensitive polyurethane material is exposed to the mask plate with the target pattern of grating structure under the ultraviolet light with a wavelength of 365 nm, and then developed by the developing agent to obtain the holographic polymer material; wherein the voltage of the light source for the exposure is 10 V, the current is 3 A, and the exposure time is 10-30 s.

[0038] The developing agent is acetonitrile or ethanol.

[0039] Compared with the prior art, the present application has the following beneficial effects:

[0040] The photosensitive monomer of the application has high cross-linking activity, can be synthesized into polyurethane holographic polymer material with high efficiency by polycondensation with isocyanate, etc., and can give it the physical cross-linking photoisomerization performance. The pyridine structure produced under light conditions (365nm ultraviolet irradiation) can not only form intermolecular hydrogen bonds with the hydrogen-containing structure in the molecular chain to realize reversible cross-linking, but also can produce complexation with metal ions. The photosensitive monomer of the application can widen the selection range of photosensitive monomers required for the production of holographic polymer materials, and effectively promote the development of holography.

[0041] The photosensitive monomer of the application has simple synthesis process and high yield, and the yield can reach 85%. It is precipitated in solid form, the product is easy to separate, has high controllability, and can realize continuous production at low cost.

[0042] The photosensitive polyurethane of the application introduces the photosensitive monomer as a blocking agent, the polyurethane (urea) structure precursor formed thereby has strong intermolecular forces, can avoid the diffusion of monomers in the polymer, and has good film-forming property. It has excellent photosensitive performance, forms ordered concave-convex plane gratings under light conditions (365nm ultraviolet irradiation), directly produces high-resolution and angle-dependent color holograms, and is suitable for large-scale use in optical anti-counterfeiting, decoration and other industries. BRIEF DESCRIPTION OF DRAWINGS

[0043] In order to more clearly illustrate the technical solutions of the embodiments of the application, the drawings needed in the embodiment description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments described in the application, and other drawings can also be obtained according to these drawings without creative labor for those skilled in the art.

[0044] Figure 1 The liquid chromatogram of the photosensitive monomer NDHP of the application is shown in the following figure;

[0045] Figure 2 The nuclear magnetic hydrogen spectrum of the photosensitive monomer NDHP of the application is shown in the following figure;

[0046] Figure 3 The ultraviolet absorption spectrum of the photosensitive monomer NDHP of the application is shown in the following figure;

[0047] Figure 4 The real object picture of the hanger-shaped effect of the photosensitive polyurethane holographic polymer material with dihydropyridine structure as the blocking agent prepared in Example 5 is shown in the following figure;

[0048] Figure 5 The POM picture of the real object of the hanger-shaped effect of the photosensitive polyurethane holographic polymer material with dihydropyridine structure as the blocking agent prepared in Example 5 observed under a microscope is shown in the following figure. DETAILED DESCRIPTION

[0049] With reference to the drawings and the embodiments of the present application, the technical solutions in the embodiments of the present application will be clearly and completely described. Obviously, the described embodiments are some of the embodiments of the present application, but not all the embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort should fall within the scope of the present application.

[0050] In the following description of the embodiments of the present application, the terms "comprising", "containing", "having" and "including" and the like are open-ended terms, i.e., meaning "including, but not limited to".

[0051] In the following description of the embodiments of the present application, the term "and / or" is used to describe the association relationship of the associated objects, which means that there can be three kinds of relationships, for example, A and / or B, which can represent the cases of A alone, B alone and A and B existing at the same time. Wherein A and B can be singular or plural. The character " / " generally represents an "or" relationship between the front and rear associated objects.

[0052] In the following description of the embodiments of the present application, the term "at least one" means one or more, and "multiple" means two or more. "At least one of the following (one)" or similar expressions means any combination of these items, including any combination of single (one) or multiple items. For example, "at least one of a, b or c", or "at least one of a, b and c", can represent a, b, c, a-b (i.e., a and b), a-c, b-c, or a-b-c, wherein a, b, and c can be single or multiple.

[0053] The terms used in the embodiments of the present application are merely for the purpose of describing specific embodiments, and are not intended to limit the present application. The singular forms "a" and "the" used in the embodiments of the present application and the appended claims are also intended to include the plural forms, unless the context clearly indicates otherwise.

[0054] Those skilled in the art should understand that in the following description of the embodiments of the present application, the order of the serial numbers does not mean the order of execution, and some or all steps can be executed in parallel or in sequence, and the execution order of each process should be determined according to its function and inherent logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0055] Those skilled in the art should understand that the numerical ranges in the embodiments of the present application should be understood as each intermediate value between the upper limit and the lower limit of the range. Each smaller range between any stated value or stated range and any other stated value or intermediate value within the stated range is also included in the present application. The upper limit and the lower limit of these smaller ranges can be independently included or excluded from the range.

[0056] Unless otherwise indicated, the technical / scientific terms used herein have the same meaning as is commonly understood by one of ordinary skill in the art to which this application belongs. Although methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present application, the preferred methods and materials are described. All documents mentioned herein are incorporated by reference to disclose and describe in full the methods and / or materials which are described therein. In case of conflict, the content of the present specification will control.

[0057] In a first aspect, the present application provides a photosensitive monomer, whose chemical structure is shown as formula (1):

[0058]

[0059] The photosensitive monomer is prepared by reacting 5-hydroxy-2-nitrobenzaldehyde with compound M and compound N in a first polar solvent. In the present application, the photosensitive monomer is denoted as NDHP.

[0060] Specifically, 5-hydroxy-2-nitrobenzaldehyde, compound M and compound N are dissolved in a first polar solvent according to a molar ratio of 1:2:5, and stirred at 0-15℃ for 2-5h. The precipitated solid is the photosensitive monomer. In this ratio range, the raw materials are completely reacted, not only saving raw materials but also reducing the generation of by-products.

[0061] In the present application, the amount of the first polar solvent is at least 3 times the total mass of 5-hydroxy-2-nitrobenzaldehyde, compound M and compound N. In this range, the amount of the first polar solvent can make the raw materials well dissolved in the polar solvent, improve the yield and reduce by-products.

[0062] In the present application, the chemical structure of the compound M is shown as formula (2):

[0063]

[0064] wherein R is selected from CH3, C2H5, CH(CH3)2, CH2CH2OCH3 or CH2CH(CH3)2;

[0065] In the present application, the compound N is a Lewis acid or a Bronsted acid, wherein the Lewis acid includes trifluoroacetic acid or acetic acid; preferably, the compound N is trifluoroacetic acid.

[0066] In the present application, the first polar solvent includes any one of ethanol, acetic acid, tetrahydrofuran, methanol, trifluoroethanol, acetone, butanone, pyridine, acetonitrile or dichloromethane.

[0067] The photosensitive monomer of the present application has high cross-linking activity, can be synthesized into polyurethane holographic polymer material with high efficiency by polycondensation with isocyanate and the like, and can give the light isomerization performance of physical cross-linking, the pyridine structure generated under light conditions (365 nm ultraviolet irradiation) can not only form intermolecular hydrogen bond with the hydrogen-containing structure in the molecular chain to realize reversible cross-linking, but also can produce complexation with metal ions. The photosensitive monomer light reaction mechanism is as follows:

[0068]

[0069] The photosensitive monomer NDHP is prepared by Hantzsch reaction one-pot method, the preparation process is simple, the reaction product is directly precipitated in solid form, greatly simplifying the separation and purification operation, and no purification equipment is needed, the cost is low and convenient for large-scale continuous operation. The yield of the photosensitive monomer of the present application can reach 85%.

[0070] In a second aspect, the present application provides a photosensitive polyurethane, the chemical structure of which comprises any one of general formulae (3)-(5):

[0071]

[0072] R1 is selected from one of the following structural formulae:

[0073]

[0074] R2 is selected from one of the following structural formulae:

[0075]

[0076] R3 is selected from

[0077] Wherein, n and m are the polymerization degree, 1≤n≤20; 10≤m≤30.

[0078] In a third aspect of the present application, a preparation method of the above-mentioned photosensitive polyurethane is provided, comprising:

[0079] Step 1, dissolving diisocyanate, chain extender and soft segment in a second polar solvent, and reacting in an inert atmosphere in an ice bath to obtain an intermediate solution;

[0080] The diisocyanate is preferably toluene diisocyanate or isophorone diisocyanate;

[0081] The chain extender is an alcohol chain extender or an amine chain extender; the alcohol chain extender includes any one of 1,4-butylene glycol (BDO), 1,6-hexanediol or glycerol; the amine chain extender includes ethylenediamine (DA) or N,N-dihydroxy(diisopropyl) aniline;

[0082] The soft segment comprises at least two -OH / -NH2 functional groups, preferably polytetrahydrofuran;

[0083] The second polar solvent comprises at least one of chloroform, dichloromethane, butyrolactone, butyl acetate, acetone, cyclopentanone, cyclohexanone, benzene, toluene, xylene, dioxane, dimethyl sulfoxide, sulfolane, N,N-dimethylformamide, N,N-dimethylacetamide, N-methyl-2-pyrrolidone or N-vinyl-2-pyrrolidone.

[0084] Step 2, the photosensitive monomer solution dissolved in the second polar solvent is added to the intermediate solution, and the temperature is raised to 35-45°C for reaction, and then raised to 55-65°C for reaction, to obtain the photosensitive polyurethane.

[0085] The photosensitive monomer is the photosensitive monomer described in the application, and its chemical structural formula is:

[0086]

[0087] In the application, the molar ratio of the photosensitive monomer, diisocyanate, chain extender and soft segment is preferably 1:7.2:5:(0-3.6);

[0088] The amount of the second polar solvent is preferably at least 2 times the total amount of the photosensitive monomer, diisocyanate, chain extender and soft segment.

[0089] The photosensitive polyurethane of the application introduces the photosensitive monomer as a capping agent, and the polyurethane (urea) structure precursor formed thereby has strong intermolecular forces, which can avoid the diffusion of monomers in the polymer, so that the polymer has good film-forming properties. The photosensitive polyurethane has excellent photosensitivity, and can form an ordered concave-convex planar grating under light conditions (365 nm ultraviolet irradiation), directly producing a color hologram with high resolution and angle dependence.

[0090] The photosensitive monomer or the photosensitive polyurethane of the application both have excellent photosensitivity, and can be used as or for preparing anti-counterfeiting encrypted polymer materials. The photosensitive monomers widen the selection range of the photosensitive monomers required for the production of holographic polymer materials, and effectively promote the development of holography.

[0091] The application further provides a holographic polymer material comprising the photosensitive polyurethane described above. The holographic polymer material of the application has excellent photosensitivity, and can form an ordered concave-convex planar grating under light conditions (365 nm ultraviolet irradiation), directly producing a color hologram with high resolution and angle dependence, and is suitable for large-scale use in the fields of optical anti-counterfeiting and decoration.

[0092] In the application, the preparation method of the holographic polymer material comprises:

[0093] The photosensitive polyurethane material is exposed under ultraviolet light with a wavelength of 365 nm through a mask plate with a target pattern of grating structure, and then developed by a developer to obtain a holographic polymer material; wherein the voltage of the light source for exposure is 10 V, the current is 3 A, and the exposure time is 10-30 s.

[0094] The developer includes an organic solvent and metal ions dissolved in the organic solvent, and the metal ions can have a complexation reaction with the photosensitive molecules. The developer can be AR grade acetonitrile or AR grade ethanol, which can be directly obtained by purchasing a commodity. As preferred, metal ions such as palladium ions can be added to the developer, and the metal ions can have a complexation with the pyridine structure generated by the photosensitive monomer under light conditions (365 nm ultraviolet irradiation), so as to achieve a better development effect.

[0095] The application is further illustrated by the following examples.

[0096] Example 1

[0097] The embodiment provides a preparation method of a photosensitive monomer, including:

[0098] S1, 10 mmol of 5-hydroxy-2-nitrobenzaldehyde, 20 mmol of 3-aminocrotonic acid methyl ester, 50 mmol of trifluoroacetic acid and 31.56 g of anhydrous ethanol are added to a single-neck flask under ice bath, and the reaction is stirred under magnetic stirring under ice bath (0 ℃) for 3 h; after the reaction is completed, the solid-phase product is collected by vacuum filtration, washed with anhydrous ethanol, and then dried to obtain a solid powder, to obtain the photosensitive monomer, denoted as NDHP, and the yield is 87.7%; the synthesis route is as follows:

[0099]

[0100] Example 2

[0101] The embodiment provides a preparation method of a photosensitive polyurethane, including:

[0102] S1, 3.6 mmol of toluene diisocyanate, 2.5 mmol of 1,4-butanediol, 0.5 mmol of NDHP and 2.57 g of N,N-dimethylacetamide are weighed under anhydrous and anaerobic inert environment; the toluene diisocyanate, 1,4-butanediol and NDHP are dissolved in a part of N,N-dimethylacetamide, and the reaction is carried out under ice bath for 4 h to obtain an intermediate solution;

[0103] S2, dissolve NDHP in the remaining N,N-dimethylacetamide to obtain an NDHP solution, and add the NDHP solution to the intermediate solution, and then sequentially stir at 40°C and 60°C overnight to obtain a photosensitive polyurethane solution capped with a dihydropyridine structure, denoted as A-PU solution;

[0104] S3, after the A-PU solution is filtered to remove impurities, spin coating is performed on a clean glass substrate in a dark room at room temperature, and then a hot air gun is used to heat and blow for 10s to obtain a photosensitive polyurethane film capped with a dihydropyridine structure, denoted as A-PU film.

[0105] The synthetic reaction formula is:

[0106]

[0107] Example 3

[0108] The embodiment provides a preparation method of a photosensitive polyurethane, comprising:

[0109] S1, in an inert environment free of water and oxygen, 3.6mmol of toluene diisocyanate, 2.5mmol of 1,4-butanediol, 0.5mmol of NDHP, 1.8mmol of polytetrahydrofuran with a molecular weight of 2000, and 2.57g of N,N-dimethylacetamide are weighed;

[0110] The toluene diisocyanate and the polytetrahydrofuran are dissolved in part of the N,N-dimethylacetamide, and reacted in an ice bath for 4h; 1,4-butanediol is added, and then stirred and reacted for 4h to obtain an intermediate solution;

[0111] S2, dissolve NDHP in the remaining N,N-dimethylacetamide to obtain an NDHP solution, and add the NDHP solution to the intermediate solution, and then sequentially stir at 40°C and 60°C overnight to obtain a photosensitive polyurethane solution capped with a dihydropyridine structure, denoted as B-PU solution;

[0112] S3, after the B-PU solution is filtered to remove impurities, spin coating is performed on a clean glass substrate in a dark room at room temperature, and then a hot air gun is used to heat and blow for 10s to obtain a photosensitive polyurethane film capped with a dihydropyridine structure, denoted as B-PU film.

[0113] The synthetic reaction formula is:

[0114]

[0115] Example 4

[0116] The embodiment provides a preparation method of a photosensitive polyurethane, comprising:

[0117] S1, under the inert environment of no water and no oxygen, 3.6 mmol of isophorone diisocyanate, 2.5 mmol of 1,4-butanediol, 0.5 mmol of NDHP, 1.8 mmol of polytetrahydrofuran with a molecular weight of 2000, and 2.57 g of N,N-dimethylacetamide were weighed;

[0118] Isophorone diisocyanate and polytetrahydrofuran were dissolved in a part of N,N-dimethylacetamide, and the reaction was carried out in an ice bath for 4 h; 1,4-butanediol was added, and the reaction was stirred for another 4 h to obtain an intermediate solution;

[0119] S2, the NDHP was dissolved in the remaining N,N-dimethylacetamide to obtain an NDHP solution, and the NDHP solution was added to the intermediate solution, and the temperature was sequentially increased to 40°C and 60°C and stirred overnight to obtain a photosensitive polyurethane solution capped with a dihydropyridine structure, denoted as C-PU solution;

[0120] S3, after the C-PU solution was filtered to remove impurities and spin-coated on a clean glass substrate in a room-temperature light-proof environment, a hot air gun was used to heat and blow for 10 s to obtain a photosensitive polyurethane film capped with a dihydropyridine structure, denoted as C-PU film.

[0121] The synthesis reaction formula is:

[0122]

[0123] Example 5

[0124] The present embodiment provides a preparation method of a holographic polymer material, comprising:

[0125] A photosensitive polyurethane A-PU film prepared in Example 2 was exposed to light for 30 s through a mask plate with a back-shaped target pattern using a 365 nm ultraviolet light source; after the exposure was completed, the polymer-type holographic recording material A-PU was immersed in acetonitrile for adsorption development treatment; after being taken out, it was washed with acetonitrile, dried, the drying temperature was 50°C, and the time was 10 s, to obtain a holographic polymer material recording holographic information.

[0126] The photosensitive monomer prepared in Example 1 was tested by nuclear magnetic resonance, and the liquid chromatogram is shown in Figure 1 , the nuclear magnetic hydrogen spectrum is shown in Figure 2 , and the ultraviolet absorption spectrum is shown in Figure 3 .

[0127] It can be seen from Figure 1 that the molecular weight test of the photosensitive monomer synthesized and purified is correct, and the photosensitive monomer is successfully prepared.

[0128] From Figure 2It can be seen from the NMR integration graph of the photosensitive monomer that the value of the pyridine hydrogen position is less than 1, which proves that the content of the pyridine hydrogen has been changed;

[0129] From Figure 3 It can be seen that, with the increase of the ultraviolet light irradiation time, the absorption peak intensity at 225-260 nm is weakened, the absorption peak intensity at 260-300 nm is enhanced, the absorption peak intensity at 300-375 nm is weakened, and the absorption peak intensity at 375-460 nm is enhanced, which proves the photosensitivity of the molecule and the change of the molecular structure.

[0130] Figure 4 The actual picture of the photosensitive polyurethane holographic macromolecular material with dihydropyridine structure as the end-capped prepared in Example 5 of the present application, wherein the photosensitive polyurethane film is exposed for 30 s and developed once. It can be seen from the figure that Figure 4 It can be seen that the polymer film with the required pattern is successfully prepared.

[0131] Figure 5 The structure of the holographic macromolecular material prepared in Example 5 under a microscope. It can be seen from the figure that Figure 5 It can be seen that the holographic macromolecular material forms a controllable periodic grating wrinkle, which can directly produce a high-resolution and angle-dependent color hologram, and is suitable for large-scale use in optical anti-counterfeiting, decoration and other fields.

[0132] Although the present application has been described in detail in the specification and specific embodiments, some modifications or improvements can be made on the basis of the present application, which is obvious to those skilled in the art. Therefore, these modifications or improvements made on the basis of not deviating from the spirit of the present application, all belong to the scope of the present application.

Claims

1. A photosensitive polyurethane, characterized by, It is selected from any one of the following compounds: ； ； Wherein, n and m are the degree of polymerization, 1n20; 10m30.

2. The method for preparing photosensitive polyurethane according to claim 1, characterized in that, It comprises: Dissolve the diisocyanate, chain extender and soft segment in the second polar solvent, and carry out the reaction in an inert atmosphere in an ice bath to obtain an intermediate solution; The diisocyanate comprises toluene diisocyanate or isophorone diisocyanate; The chain extender is 1,4-butanediol; The soft segment is a polyether containing two -OH functional groups; Add the photosensitive monomer solution dissolved in the second polar solvent to the intermediate solution, heat to 35-45 DEG C to react, and then heat to 55-65 DEG C to react to obtain a photosensitive polyurethane.

3. The method of claim 2, wherein, The molar ratio of the photosensitive monomer, diisocyanate, chain extender and soft segment is 1:7.2:5:(0-3.6), wherein the amount of the soft segment cannot be 0; The amount of the second polar solvent is at least 2 times the total amount of the photosensitive monomer, diisocyanate, chain extender and soft segment.

4. The preparation method of claim 2, wherein, The second polar solvent comprises at least one of chloroform, dichloromethane, butyrolactone, butyl acetate, acetone, cyclopentanone, cyclohexanone, benzene, toluene, xylene, dioxane, dimethyl sulfoxide, sulfolane, N,N-dimethylformamide, N,N-dimethylacetamide, N-methyl-2-pyrrolidone or N-vinyl-2-pyrrolidone.

5. The photosensitive polyurethane of claim 1 is applied in anti-counterfeiting encryption polymer materials.

6. A holographic high molecular material, characterized by, It comprises the photosensitive polyurethane of claim 1.

7. The method for preparing the holographic polymer material according to claim 6, characterized in that, It comprises: Exposure of the photosensitive polyurethane material to a mask plate with a target pattern of grating structure under ultraviolet light with a wavelength of 365 nm, and then developing with a developer to obtain a holographic polymer material; wherein the voltage of the light source for exposure is 10 V, the current is 3 A, and the exposure time is 10-30 s; The developer is acetonitrile or ethanol.

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