A flexible photosensitive polyurethane film and a method for preparing the same

Abstract

The application relates to the technical field of polyurethane materials, and discloses a flexible photosensitive polyurethane film and a preparation method thereof. The preparation method of the flexible photosensitive polyurethane film comprises the following steps: preparing a photosensitive monomer; obtaining a polyurethane solution through one-pot reaction of diisocyanate, a soft segment diol and the photosensitive monomer; and coating the polyurethane solution on a substrate to obtain the flexible photosensitive polyurethane film after drying. The flexible photosensitive polyurethane film is prepared by using a one-step synthesis process, the preparation process is simple, and the production efficiency is improved. The flexible photosensitive polyurethane film prepared by the application has high photosensitivity and pattern resolution, highly regular microstructures can be accurately constructed on the surface of the film through photomask and ultraviolet exposure treatment, the processing technology is simple, and complex highly ordered patterns can be realized; and the microstructures on the surface of the film can evolve over time, so that the material surface is endowed with the characteristic that the optical performance of the material surface changes over time.

Description

TECHNICAL FIELD

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

[0002] In the rapidly developing field of science and technology, flexible materials are gradually becoming the key driving force for innovation in multiple industries due to their unique physical and chemical properties. As an important member of flexible materials, polyurethane (PU) film has shown great application potential in multiple fields such as electronic display, wearable devices, medical devices, packaging materials, and automotive interiors, due to its excellent flexibility, wear resistance, chemical corrosion resistance, and good processing performance.

[0003] Although traditional polyurethane films already have good overall performance, it is still a challenging task to prepare a surface morphology with high regularity on the surface of a polyurethane polymer. In the prior art, the microstructure of the surface of a traditional polyurethane film is usually constructed by physical or chemical means, and these methods often have problems such as complex processing, high cost, and difficulty in achieving fine control. In addition, these traditional methods are difficult to form highly ordered patterns on the surface of a polyurethane polymer, limiting their application in high-performance optical encryption materials and other fields. SUMMARY

[0004] The present application provides a flexible photosensitive polyurethane film and a preparation method thereof, aiming to solve the problem of complex processing technology for constructing microstructure on the surface of a polyurethane film in the prior art and the difficulty in forming highly ordered patterns.

[0005] To achieve the above-mentioned purpose, the following technical solutions are adopted in the present application.

[0006] In a first aspect of the present application, a preparation method of a flexible photosensitive polyurethane film is provided, comprising:

[0007] preparing a photosensitive monomer;

[0008] obtaining a polyurethane solution by one-pot reaction of diisocyanate, soft segment diol, and photosensitive monomer;

[0009] coating the polyurethane solution on a substrate and obtaining a flexible photosensitive polyurethane film after drying.

[0010] Preferably, the molar ratio of diisocyanate, soft segment diol, and photosensitive monomer is 2:(0.2-2.0):(0.1-1.8).

[0011] The temperature of the one-pot reaction is 20-100℃.

[0012] Preferably, the soft segment diol includes any one of 1,4-butanediol, 1,2-propanediol, 1,3-propanediol, 1,6-hexanediol, ethylene glycol adipate, 1,4-butanediol terephthalate, decanediol glycol, polypropylene oxide diol, polyethylene glycol, polytetrahydrofuran diol, polycarbonate diol, polyhexanediol, polybutanediol, polyethylene oxide-propylene oxide copolyether, glycerol, sorbitol, or polycaprolactone diol.

[0013] Preferably, the chemical structure of the photosensitive monomer is shown in formula (1):

[0014]

[0015] wherein R1, R2, R3, R4, R5, R6, R7 are each independently selected from any one of hydrogen, C 1～20 aryl, C 1～20 heteroaryl, C 1～20 alkyl, C 1～20 acyl, C 1～20 ester, C 1～20 ketone, C 1～20 aldehyde, C 1～20 alkoxy, C 1～20 aryloxy.

[0016] Preferably, the photosensitive monomer is prepared by the following method:

[0017] S1, disperse the halogenated phenol and the halogenated ester in a solvent, and perform a nucleophilic substitution reaction under the action of a first catalyst to obtain compound A;

[0018] S2, mix compound A and a Lewis base in a solvent until homogeneous, and perform a nucleophilic substitution reaction by adding an acid compound to obtain compound B;

[0019] S3, dissolve compound B and anthracenol in a solvent, and perform an esterification reaction under the action of a second catalyst to obtain compound C;

[0020] S4, disperse compound C and aminobenzene boronic acid in a solvent in an acidic environment, and perform a reaction under the action of a third catalyst to obtain the photosensitive monomer.

[0021] Further preferably, the chemical structure of the halogenated phenol is shown in formula (2):

[0022]

[0023] The chemical structure of the aminobenzene boronic acid is shown in formula (3):

[0024]

[0025] wherein R1, R2, R3, R4, R5, R6, R7are each independently selected from hydrogen, C 1～20 aryl, C 1～20 heteroaryl, C 1～20 alkyl, C 1～20 acyl, C 1～20 ester, C 1～20 keto, C 1～20 aldehyde, C 1～20 alkoxy, C 1～20 aryloxy, C

[0026] The halogenated ester includes any one of methyl fluoroacetate, ethyl fluoroacetate, phenyl fluoroacetate, methyl chloroacetate, phenyl chloroacetate, ethyl chloroacetate, methyl bromoacetate, ethyl bromoacetate, phenyl bromoacetate, ethyl 2-bromopropionate, ethyl 3-bromopropionate, ethyl 4-bromobutyrate, methyl iodoacetate, ethyl iodoacetate, phenyl iodoacetate, ethyl 2,2-dichloropropionate, or 1,1,1-trifluoro-2-chloroethane.

[0027] Further preferably, the first catalyst includes any one of potassium carbonate, potassium hydroxide, sodium hydroxide, triethylamine, pyridine, sodium carbonate, sodium acetate, potassium acetate, potassium phosphate, or tetramethylammonium chloride;

[0028] and / or,

[0029] The Lewis base includes at least one of lithium hydroxide, sodium hydroxide, potassium hydroxide, calcium hydroxide, magnesium hydroxide, lithium carbonate, sodium carbonate, potassium carbonate, rubidium carbonate, cesium carbonate, beryllium carbonate, magnesium carbonate, calcium carbonate, strontium carbonate, barium carbonate, sodium hydride, calcium hydride;

[0030] and / or,

[0031] The acid compound includes at least one of hydrochloric acid, sulfuric acid, phosphoric acid, acetic acid, perchloric acid, nitric acid, trifluoroacetic acid, formic acid, dimethyl sulfate, ferric chloride, boron tribromide, aluminum tribromide, or boron trifluoride etherate;

[0032] and / or,

[0033] The second catalyst includes at least one of triethylenediamine, triethylamine, potassium carbonate, sodium hydroxide, potassium hydroxide, 4-dimethylaminopyridine, 1-ethyl-(3-dimethylaminopropyl)carbodiimide, 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride, N-hydroxysuccinimide, N,N-carbodiimidazole, dicyclohexylcarbodiimide, trifluoroacetic acid, 2-(7-azabenzotriazol)-N,N,N',N'-tetramethyluronium hexafluorophosphate, tributylthiourea, benzotriazol-1-yl-oxytris-pyrrolidino-phosphonium hexafluorophosphate, diethylphosphoryl ethyl triethoxysilane, acetamide, or 1-hydroxybenzotriazole.

[0034] and / or,

[0035] The third catalyst includes any one of ruthenium (II) diphenylphosphine dichloride, ruthenium (II) diphenylphosphine trifluoroacetate, nickel dichloride, diisopropyl nickel chloride, nickel (II) phosphine triphenyl, copper (I) iodide, copper (I) iodide, copper (II) acetate, iron (III) acetylacetone, iron (III) chloride, triethylamine, pyridine, 4-(N,N-dimethylamino) pyridine, triphenylphosphine, tributylphosphine, triphenylphosphine palladium, palladium-copper complex catalyst, palladium-nickel complex catalyst, benzophenone, sulfuric acid or trifluoroacetic acid;

[0036] and / or,

[0037] The solvent is at least one of water, methanol, ethanol, acetonitrile, tetrahydrofuran, acetone, cyclopentanone, cyclohexanone, dichloromethane, chloroform, N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, dioxane, hexafluoroisopropanol, cyclobutane sulfone, N-methyl-2-pyrrolidone, m-cresol, dimethylphenol, benzene, toluene, xylene, N-vinyl-2-pyrrolidone, butyrolactone, butyl acetate.

[0038] Further preferably, in S1, the molar ratio of the halogenated phenol, the halogenated ester and the first catalyst is 1:(0.5-1.5):(1.5-2.5); the temperature of the nucleophilic substitution reaction is 20-100℃;

[0039] In S2, the mass ratio of the compound A, the Lewis base and the solvent is 1:(1.5-2.0):(2.3-4.0); the temperature of the nucleophilic substitution reaction is 20-100℃;

[0040] In S3, the molar ratio of the compound B, the second catalyst and anthranol is 1:(2.1-3.4):(0.8-1.2); the temperature of the esterification reaction is 20-100℃;

[0041] In S4, the molar ratio of the compound C, the aminobenzene boronic acid, the third catalyst and the solvent is 1:(2.5-4.5):(0.01-0.02):(220-250); the temperature of the reaction is 20-100℃.

[0042] In the second aspect of the present application, a flexible photosensitive polyurethane film prepared by the above preparation method is provided.

[0043] In the third aspect of the present application, a method for constructing a microstructure on the surface of a flexible photosensitive polyurethane film is provided, which comprises:

[0044] The above flexible photosensitive polyurethane film is subjected to ultraviolet exposure through a photomask, and then is developed by a developing agent, so that a microstructure is constructed on the surface thereof.

[0045] The developer includes at least one of acetone, toluene, ethanol, isopropanol, dimethylformamide, tetrahydrofuran, acetonitrile, petroleum ether, dichloromethane, ethyl acetate, benzene, cyclohexane, sodium hydroxide, potassium hydroxide, sodium carbonate, hydrochloric acid, sulfuric acid, phosphoric acid, sodium chloride, potassium chloride, alkylphenol polyoxyethylene ether, fatty alcohol polyoxyethylene ether, sodium dodecyl sulfate, sodium dodecyl benzene sulfonate, hydrogen peroxide, persulfate, sodium sulfite or sodium bisulfite.

[0046] Compared with the prior art, the application has the following beneficial effects:

[0047] The flexible photosensitive polyurethane film is prepared by using a one-step synthesis process, the preparation process is simple, the complexity and uncertainty in the production process are reduced, and the production efficiency is improved.

[0048] The flexible photosensitive polyurethane film prepared by the application has high photosensitivity and pattern resolution, and through light mask and ultraviolet exposure treatment, a highly regular microstructure can be accurately constructed on the surface thereof, not only the processing technology is simple, but also a complex highly ordered pattern can be realized. The microstructure on the surface of the photosensitive polyurethane film of the application can evolve over time, endowing the material surface with the feature that the optical performance changes over time, and widening the application field thereof. BRIEF DESCRIPTION OF DRAWINGS

[0049] 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 those skilled in the art can also obtain other drawings according to these drawings without creating any creative labor.

[0050] Figure 1 It is the topographic map of the light mask under the microscope.

[0051] Figure 2 It is the microscope topographic map of the flexible photosensitive polyurethane film prepared in Example 1 after light mask ultraviolet exposure;

[0052] Figure 3 It is the microscope topographic map of the flexible photosensitive polyurethane film prepared in Example 3 after light mask ultraviolet exposure;

[0053] Figure 4 It is the microscope topographic map of the flexible photosensitive polyurethane film prepared in Example 4 after light mask ultraviolet exposure. DETAILED DESCRIPTION

[0054] With reference to the drawings, the technical solutions in the embodiments of the present application will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art without creative effort are within the scope of protection of the present application.

[0055] 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".

[0056] 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.

[0057] 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 the like 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.

[0058] 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.

[0059] 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.

[0060] 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.

[0061] Unless otherwise defined, all technical / scientific terms used herein have the same meaning as 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, preferred methods and materials are described. All documents mentioned herein are incorporated by reference to disclose and describe the methods and / or materials in connection with which the documents are cited. In case of conflict between the content of the specification and that of any document incorporated herein by reference, the content of the specification prevails.

[0062] In a first aspect, the present application provides a method for preparing a flexible photosensitive polyurethane film, comprising:

[0063] preparing a photosensitive monomer;

[0064] reacting diisocyanate, soft segment diol and the photosensitive monomer by one-pot method to obtain a polyurethane solution;

[0065] coating the polyurethane solution on a substrate, and peeling off the flexible photosensitive polyurethane film from the substrate after vacuum drying.

[0066] In the present application, the molar ratio of the diisocyanate, the soft segment diol and the photosensitive monomer is preferably 2:(0.2-2.0):(0.1-1.8), and the temperature of the one-pot method is 20-100°C. The substrate can be selected from a glass sheet, a plastic sheet and other sheet-shaped materials with smooth surface.

[0067] In the present application, the soft segment diol includes any one of 1,4-butanediol, 1,2-propanediol, 1,3-propanediol, 1,6-hexanediol, ethylene glycol adipate, 1,4-butanediol terephthalate, decanediol glycol, polypropylene oxide diol, polyethylene glycol, polytetrahydrofuran diol, polycarbonate diol, polyhexanediol, polybutanediol, polyethylene-propylene oxide copolyether, glycerol, sorbitol or polycaprolactone diol; and the diisocyanate is preferably isophorone diisocyanate or hexamethylene diisocyanate.

[0068] In the present application, the photosensitive monomer has a chemical structure as shown in formula (1):

[0069]

[0070] wherein R1, R2, R3, R4, R5, R6, R7 are each independently selected from hydrogen, C 1～20 aryl, C 1～20 heteroaromatic, C 1～20 alkyl, C 1～20 acyl, C 1～20 ester, C 1～20 ketone, C 1～20 aldehyde, C1～20 Alkoxy, C 1～20 Any one of the aryloxy groups.

[0071] The photosensitive monomer is prepared by the following method:

[0072] S1, the halophenol and haloester are dispersed in a solvent and subjected to a nucleophilic substitution reaction at 20-100°C under the action of a first catalyst. The reaction product is separated by column chromatography to obtain compound A. Preferably, the molar ratio of halophenol, haloester and first catalyst is 1:(0.5-1.5):(1.5-2.5).

[0073] The chemical structure of the halophenol is shown in formula (2):

[0074]

[0075] Among them, R1, R2, and R3 are each independently selected from hydrogen and C. 1～20 Aryl, C 1～20 Heterocyclic aryl, C 1～20 Alkyl, C 1～20 Acyl group, C 1～20 Ester group, C 1～20 Ketone, C 1～20 Aldehyde group, C 1～20 Alkoxy, C 1～20 Any one of the aryloxy groups. In the embodiments of this application, preferably R1, R2, and R3 are all hydrogen.

[0076] Specifically, the haloesters include any one of methyl fluoroacetate, ethyl fluoroacetate, phenyl fluoroacetate, methyl chloroacetate, phenyl chloroacetate, ethyl chloroacetate, methyl bromoacetate, ethyl bromoacetate, phenyl bromoacetate, ethyl 2-bromopropionate, ethyl 3-bromopropionate, ethyl 4-bromobutyrate, methyl iodoacetate, ethyl iodoacetate, phenyl iodoacetate, ethyl 2,2-dichloropropionate, or 1,1,1-trifluoro-2-chloroethane.

[0077] The first catalyst comprises any one of potassium carbonate, potassium hydroxide, sodium hydroxide, triethylamine, pyridine, sodium carbonate, sodium acetate, potassium acetate, potassium phosphate, or tetramethylammonium chloride;

[0078] In this application, the solvents described in step S1, and subsequent steps S2 and S3, include at least one of the following: water, methanol, ethanol, acetonitrile, tetrahydrofuran, acetone, cyclopentanone, cyclohexanone, dichloromethane, chloroform, N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, dioxane, hexafluoroisopropanol, sulfolane, N-methyl-2-pyrrolidone, m-cresol, xylenol, benzene, toluene, xylene, N-vinyl-2-pyrrolidone, butyrolactone, and butyl acetate.

[0079] S2, mixing compound A, Lewis base into solvent to be homogeneous, adding acid compound to carry out nucleophilic substitution reaction at 20-100℃, and the reaction product is filtered under vacuum to obtain compound B; wherein, preferably the molar ratio of compound A, Lewis base and solvent is 1: (1.5-2.0): (2.3-4.0).

[0080] In the present application, the Lewis base includes at least one of lithium hydroxide, sodium hydroxide, potassium hydroxide, calcium hydroxide, magnesium hydroxide, lithium carbonate, sodium carbonate, potassium carbonate, rubidium carbonate, cesium carbonate, beryllium carbonate, magnesium carbonate, calcium carbonate, strontium carbonate, barium carbonate, sodium hydride, and calcium hydride;

[0081] The acid compound includes at least one of hydrochloric acid, sulfuric acid, phosphoric acid, acetic acid, perchloric acid, nitric acid, trifluoroacetic acid, formic acid, dimethyl sulfate, ferric chloride, boron tribromide, aluminum tribromide, or boron trifluoride etherate.

[0082] S3, dissolving compound B and anthranol in a solvent, and esterification reaction occurs under the action of a second catalyst, the reaction product is washed with acid, dried, and column chromatography separation to obtain compound C; wherein, the molar ratio of compound B, the second catalyst and anthranol is 1: (2.1-3.4): (0.8-1.2).

[0083] In the present application, the second catalyst includes at least one of triethylenediamine, triethylamine, potassium carbonate, sodium hydroxide, potassium hydroxide, 4-dimethylamino pyridine, 1-ethyl-(3-dimethylaminopropyl) carbonyl diimide, 1-ethyl-(3-dimethylaminopropyl) carbonyl diimide hydrochloride, N-hydroxysuccinimide, N,N-carbonyldiimidazole, dicyclohexyl carbodiimide, trifluoroacetic acid, 2-(7-azabenzotriazol)-N,N,N',N'-tetramethyluronium hexafluorophosphate, tributyl thiourea, benzotriazole-1-yl-oxytripyrrolidinophosphonium hexafluorophosphate, diethyl phosphoryl ethyl triethoxy silane, acetamide, or 1-hydroxybenzotriazole.

[0084] S4, dispersing compound C and aminobenzene boronic acid in a solvent under acidic conditions, and reacting at 20-100℃ under the action of a third catalyst, removing water and carbon dioxide in the reaction system with potassium carbonate, collecting the solid phase by rotary evaporation, and then column chromatography separation to obtain a photosensitive monomer. Wherein, the molar ratio of compound C, aminobenzene boronic acid, third catalyst and solvent is 1: (2.5-4.5): (0.01-0.02): (220-250).

[0085] In the present application, the chemical structure of the aminobenzene boronic acid is shown in formula (3):

[0086]

[0087] wherein R4, R5, R6, R7are each independently selected from the group consisting of hydrogen, C 1～20 aryl, C 1～20 heteroaryl, C 1～20 alkyl, C 1～20 acyl, C 1～20 ester, C 1～20 keto, C 1～20 aldehyde, C 1～20 alkoxy, C 1～20 aryloxy, C

[0088] The third catalyst includes any one of ruthenium (II) diphenylphosphine dichloride, ruthenium (II) diphenylphosphine trifluoroacetate, nickel dichloride, diisopropyl nickel chloride, nickel (II) phosphorus triphenyl, copper (I) iodide, copper (I) iodide, copper (II) acetate, iron (III) acetylacetone, iron (III) chloride, triethylamine, pyridine, 4- (N, N-dimethylamino) pyridine, triphenylphosphine, tributylphosphine, triphenylphosphine palladium, palladium-copper composite catalyst, palladium-nickel composite catalyst, benzophenone, sulfuric acid or trifluoroacetic acid.

[0089] The present application adopts a one-step synthesis process to prepare a flexible photosensitive polyurethane film, which has simple preparation process, reduces the complexity and uncertainty in the production process, and improves the production efficiency.

[0090] The flexible photosensitive polyurethane film prepared by the present application has high photosensitivity and pattern resolution, and through light mask and ultraviolet exposure treatment, a highly regular microstructure can be accurately constructed on its surface, which not only has simple processing technology, but also can realize complex and highly ordered patterns.

[0091] In a third aspect, the present application provides a method for constructing a microstructure on the surface of a flexible photosensitive polyurethane film, comprising:

[0092] The above-mentioned flexible photosensitive polyurethane film is subjected to ultraviolet exposure through a light mask, and then is developed by a developing agent, so that a microstructure can be constructed on the surface thereof. Specifically, the exposed part generates a cross-linking reaction to form a polymer insoluble in the developing agent, and the unexposed part of the flexible photosensitive polyurethane film is dissolved and removed by the developing agent, so as to present the required pattern.

[0093] The developing agent includes at least one of acetone, toluene, ethanol, isopropyl alcohol, dimethylformamide, tetrahydrofuran, acetonitrile, petroleum ether, dichloromethane, ethyl acetate, benzene, cyclohexane, sodium hydroxide, potassium hydroxide, sodium carbonate, hydrochloric acid, sulfuric acid, phosphoric acid, sodium chloride, potassium chloride, alkylphenol polyoxyethylene ether, fatty alcohol polyoxyethylene ether, sodium dodecyl sulfate, sodium dodecyl benzene sulfonate, hydrogen peroxide, persulfate, sodium sulfite or sodium bisulfite.

[0094] The microstructure of the photosensitive polyurethane film of the present application can evolve over time, endowing the material with the characteristic of time-varying optical properties of the surface, thus broadening the application field thereof.

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

[0096] Example 1

[0097] The present example provides a method for preparing a photosensitive monomer and a photosensitive polyurethane film, comprising:

[0098] S1, 0.0256 mol of ethyl 4-bromobutyrate and 0.0256 mol of dibromophenol were added to a flask, and 50 ml of acetone and 0.0513 mol of potassium carbonate were added, and water was removed and sealed. The mixture was warmed to 70°C and condensed to reflux for 24 h. After the reaction was completed, it was cooled to room temperature, rotary evaporated and separated by column chromatography to obtain 0.01977 mol of compound A;

[0099] S2, 0.0362 mol of sodium hydroxide, 0.01977 mol of compound A, 0.03 mol of methanol and 0.03 mol of water were added to a beaker to form a homogeneous phase, and hydrolysis was carried out. After the reaction was completed, 0.0445 mol of compound B was obtained by filtration under reduced pressure, and then dissolved in dichloromethane to prepare a solution;

[0100] S3, 0.0917 mol of 1-ethyl-(3-dimethylaminopropyl) carbodiimide, 0.0089 mol of 4-dimethylaminopyridine, 0.0475 mol of anthranol and 0.0445 mol of compound B were added to 1.37 mol of dichloromethane, and stirred for three days. After the reaction was completed, 0.4 mol of 1 mol / L hydrochloric acid was added to the reaction product in three portions, and then potassium carbonate solution was added to remove hydrochloric acid. The potassium carbonate solid was dehydrated, and a clear and transparent solution was obtained at this time. The product was determined by thin layer chromatography, and compound C was separated by column chromatography;

[0101] S4, 0.00494 mol of compound C was taken, tetrahydrofuran was added and rotary evaporated, and then 0.0147 mol of 4-aminobenzoic acid hydrochloride, 0.00038 mol of triphenylphosphine palladium, 0.0491 mol of potassium carbonate, 0.0445 mol of tetrahydrofuran and 1.11 mol of distilled water (wherein potassium carbonate is used to remove water and carbon dioxide in the reaction system) were added. Under the protection of nitrogen, it was refluxed at 70°C for 10 h, and then rotary evaporated, dichloromethane was added for column chromatography separation, and then rotary evaporated to obtain 0.0035 mol of photosensitive monomer.

[0102] S5, 2 mol of isophorone diisocyanate, 1 mol of polytetrahydrofuran (molecular weight of 1000) were added to 1 mol of the photosensitive monomer, and a one-pot method was used to heat to 70°C for 24 h. After the reaction was completed, 200 μL of the prepared polyurethane solution was uniformly coated on a glass sheet, and after being placed at 60°C for 2 h, it was dried in a vacuum oven at 60°C to obtain a flexible photosensitive polyurethane film.

[0103] The preparation process of Example 1 is shown below:

[0104]

[0105] The flexible photosensitive polyurethane film was peeled off from the glass sheet, and after being exposed to ultraviolet light with a wavelength of 365 nm for 5 s through a photomask, it was placed in a mixed developer of tetrahydrofuran and ethanol. The photomask under a microscope is shown in Figure 1 , and the surface of the developed film can form regular micron stripes, as shown in Figure 2 .

[0106] Example 2

[0107] The steps S1-S4 of preparing the photosensitive monomer in Example 2 are the same as those in Example 1.

[0108] In S5, the amount of polytetrahydrofuran (molecular weight of 1000) was changed to 1.6 mol, and the amount of photosensitive monomer was changed to 0.4 mol, and the rest was the same as in Example 1.

[0109] Example 3

[0110] The steps S1-S2 of preparing the photosensitive monomer in Example 3 are the same as those in Example 1.

[0111] S3, 0.0917 mol of 1-ethyl-(3-dimethylaminopropyl) carbodiimide, 0.0089 mol of 4-dimethylaminopyridine, 0.0475 mol of anthracene alcohol, and 0.0445 mol of compound B were added to 1.24 mol of chloroform, and stirred for three days. After the reaction was completed, 0.4 mol of 1 mol / L hydrochloric acid was added to the reaction product in three portions, and then potassium carbonate solution was added to remove the hydrochloric acid, and the potassium carbonate solid was removed to remove water, at which time a clear and transparent solution was obtained. The product was determined by thin layer chromatography, and compound C was separated by column chromatography;

[0112] S4, after adding tetrahydrofuran to compound C, rotary evaporation, then adding 0.0147 mol of 4-aminobenzoic acid hydrochloride, 0.00038 mol of triphenylphosphine palladium, 0.0491 mol of potassium carbonate, 0.0445 mol of tetrahydrofuran and 1.11 mol of distilled water, refluxing at 70°C for 10 hours under the protection of nitrogen, rotary evaporation, adding dichloromethane for column chromatography separation, and then rotary evaporation to obtain 0.0035 mol of photosensitive monomer.

[0113] S5, 2 mol of isophorone diisocyanate, 1 mol of 1,4-butanediol are added to 1 mol of photosensitive monomer, and a one-pot method is used to heat to 70°C for 24 hours. After the reaction is completed, 200 μL of the prepared polyurethane solution is uniformly coated on a glass sheet, and after being placed at 60°C for 2 hours, it is placed in a vacuum oven at 60°C for drying, to obtain a flexible photosensitive polyurethane film.

[0114] The preparation process of Example 3 is shown as follows:

[0115]

[0116] The flexible photosensitive polyurethane film is peeled off from the glass sheet, tightly adheres to the photomask, and is exposed to ultraviolet light with a wavelength of 365 nm for 5 seconds. After being placed in a mixed developer of tetrahydrofuran and ethanol, it can be observed that the surface of the film can form regular micron stripes, as shown in Figure 3 .

[0117] Example 4

[0118] The steps S1-S2 of preparing the photosensitive monomer in Example 4 are the same as those in Example 1.

[0119] S3, 0.0917 mol of 1-ethyl-(3-dimethylaminopropyl) carbodiimide, 0.0089 mol of 4-dimethylaminopyridine, 0.0475 mol of anthracene alcohol and 0.0445 mol of compound B are added to 1.71 mol of ethanol, and stirred for three days. After the reaction is completed, 0.4 mol of 1 mol / L hydrochloric acid is added to the reaction product in three portions, and then potassium carbonate solution is added to remove hydrochloric acid, and the potassium carbonate solid is removed to remove water, at which time a clear and transparent solution is obtained. The product is determined by thin layer chromatography, and compound C is separated by column chromatography;

[0120] S4, to the compound C, after adding tetrahydrofuran, spin evaporation, then add 0.0147 mol of 4-aminobenzoic acid hydrochloride, 0.00038 mol of triphenylphosphine palladium, 0.0491 mol of potassium carbonate, 0.0445 mol of tetrahydrofuran and 1.11 mol of distilled water, under the protection of nitrogen, reflux at 70°C for 10h, spin evaporation again, add dichloromethane for column chromatography separation, spin evaporation again to obtain 0.00366 mol of photosensitive monomer.

[0121] S5, 2 mol of hexamethylene diisocyanate, 1 mol of polytetrahydrofuran (molecular weight 1000) is added to 1 mol of photosensitive monomer, heated to 70°C for 24h by one pot method. After the reaction is completed, take 200 μL of the prepared polyurethane solution and evenly spread it on a glass sheet, place it in a vacuum oven at 60°C after placing it at 60°C for 2h, and a flexible photosensitive polyurethane film can be obtained.

[0122] The preparation process of Example 4 is shown as follows:

[0123]

[0124] The flexible photosensitive polyurethane film is peeled off from the glass sheet, tightly attached to the photomask, exposed to ultraviolet light with a wavelength of 365 nm for 5s, and then placed in a mixed developer of tetrahydrofuran and ethanol for development. It can be observed that the surface of the film can form regular micron stripes, as shown in Figure 4 .

[0125] From Figure 2 , Figure 3 and Figure 4 , it can be seen that the method for constructing microstructure on the surface of the flexible photosensitive polyurethane film can successfully construct highly regular microstructure on the surface of the flexible photosensitive polyurethane film. The three kinds of regular microstructure further verify the reliability and repeatability of the preparation method of the flexible photosensitive polyurethane film, which provides flexibility for adjusting the synthesis formula to adapt to different application requirements, and is beneficial to improve the optical performance of the polyurethane film and the application potential in the field of optical encryption.

[0126] 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 protection claimed by the present application.

Claims

1. A method for preparing a flexible photosensitive polyurethane film, characterized in that, include: Prepare a photosensitive monomer; the chemical structure of the photosensitive monomer is shown in formula (1): (1)； Among them, R1, R2, R3, R4, R5, R6, and R7 are each independently selected from hydrogen and C. 1~20 Aryl, C 1~20 Heterocyclic aryl, C 1~20 Alkyl, C 1~20 Acyl group, C 1~20 Ester group, C 1~20 Ketone, C 1~20 Aldehyde group, C 1~20 Alkoxy, C 1~20 Any one of the aryloxy groups; The photosensitive monomer is prepared by the following method: S1, Halophenols and haloesters are dispersed in a solvent and undergo a nucleophilic substitution reaction under the action of a first catalyst to obtain compound A; S2, Compound A and a Lewis base are added to a solvent and mixed until homogeneous. Then, an acid compound is added to carry out a nucleophilic substitution reaction to obtain compound B; S3, Compound B and anthraquinone are dissolved in a solvent and undergo esterification under the action of a second catalyst to obtain Compound C; S4, under acidic conditions, compound C and aminophenylboronic acid are dispersed in a solvent and reacted under the action of a third catalyst to obtain a photosensitive monomer; A polyurethane solution is obtained by reacting diisocyanate, soft segment diol and photosensitive monomer in a one-pot process. The molar ratio of the diisocyanate, soft segment diol, and photosensitive monomer is 2:(0.2~2.0):(0.1~1.8); The polyurethane solution is coated onto a substrate and dried to obtain a flexible photosensitive polyurethane film.

2. The preparation method according to claim 1, characterized in that, The temperature of the one-pot reaction is 20~100℃.

3. The preparation method according to claim 1, characterized in that, The soft segment diol includes any one of 1,4-butanediol, 1,2-propanediol, 1,3-propanediol, 1,6-hexanediol, ethylene glycol adipate, 1,4-butanediol terephthalate, diethylene sebacate, polypropylene glycol, polyethylene glycol, polytetrahydrofuran glycol, polycarbonate diol, polyhexanediol, polybutanediol, polyethylene oxide-propylene oxide copolyether, glycerol, sorbitol, or polycaprolactone diol.

4. The preparation method according to claim 1, characterized in that, The chemical structure of the halophenol is shown in formula (2): (2)； The chemical structure of the aminophenylboronic acid is shown in formula (3): （3）； Among them, R1, R2, R3, R4, R5, R6, and R7 are each independently selected from hydrogen and C. 1~20 Aryl, C 1~20 Heterocyclic aryl, C 1~20 Alkyl, C 1~20 Acyl group, C 1~20 Ester group, C 1~20 Ketone, C 1~20 Aldehyde group, C 1~20 Alkoxy, C 1~20 Any one of the aryloxy groups; The haloesters include any one of methyl fluoroacetate, ethyl fluoroacetate, phenyl fluoroacetate, methyl chloroacetate, phenyl chloroacetate, ethyl chloroacetate, methyl bromoacetate, ethyl bromoacetate, phenyl bromoacetate, ethyl 2-bromopropionate, ethyl 3-bromopropionate, ethyl 4-bromobutyrate, methyl iodoacetate, ethyl iodoacetate, phenyl iodoacetate, or ethyl 2,2-dichloropropionate.

5. The preparation method according to claim 1, characterized in that, The first catalyst comprises any one of potassium carbonate, potassium hydroxide, sodium hydroxide, triethylamine, pyridine, sodium carbonate, sodium acetate, potassium acetate, potassium phosphate, or tetramethylammonium chloride; And / or, The Lewis base includes at least one of lithium hydroxide, sodium hydroxide, potassium hydroxide, calcium hydroxide, magnesium hydroxide, lithium carbonate, sodium carbonate, potassium carbonate, rubidium carbonate, cesium carbonate, beryllium carbonate, magnesium carbonate, calcium carbonate, strontium carbonate, barium carbonate, sodium hydride, and calcium hydride. And / or, The acidic compounds include at least one of hydrochloric acid, sulfuric acid, phosphoric acid, acetic acid, perchloric acid, nitric acid, trifluoroacetic acid, formic acid, dimethyl sulfate, ferric chloride, boron tribromide, aluminum tribromide, or boron trifluoride diethyl ether. And / or, The second catalyst comprises at least one of the following: triethylenediamine, triethylamine, potassium carbonate, sodium hydroxide, potassium hydroxide, 4-dimethylaminopyridine, 1-ethyl-(3-dimethylaminopropyl)carbodiimide, 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride, N-hydroxysuccinimide, N,N-carbodiimidazole, dicyclohexylcarbodiimide, trifluoroacetic acid, 2-(7-azabenzotriazole)-N,N,N',N'-tetramethylurea hexafluorophosphate, tributylthiourea, benzotriazole-1-yl-oxytripyrrolidinephosphine hexafluorophosphate, diethylphosphorylethyltriethoxysilane, acetamide, or 1-hydroxybenzotriazole. And / or, The third catalyst comprises any one of ruthenium(II) diphenylphosphine dichloride, ruthenium(II) diphenylphosphine trifluoroacetate, nickel dichloride, diisopropyl nickel chloride, nickel(II) phosphorus triphenyl, copper(I) iodide, copper(II) acetate, iron(III) acetylacetone, iron(III) chloride, triethylamine, pyridine, 4-(N,N-dimethylamino)pyridine, triphenylphosphine, tributylphosphine, triphenylphosphine palladium, palladium-copper composite catalyst, palladium-nickel composite catalyst, benzophenone, sulfuric acid, or trifluoroacetic acid; And / or, The solvent is at least one of water, methanol, ethanol, acetonitrile, tetrahydrofuran, acetone, cyclopentanone, cyclohexanone, dichloromethane, chloroform, N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, dioxane, hexafluoroisopropanol, sulfolane, N-methyl-2-pyrrolidone, m-cresol, xylenol, benzene, toluene, xylene, N-vinyl-2-pyrrolidone, butyrolactone, and butyl acetate.

6. The preparation method according to claim 1, characterized in that, In S1, the molar ratio of halophenol, haloester and first catalyst is 1:(0.5~1.5):(1.5~2.5); the temperature for nucleophilic substitution reaction is 20~100℃; In S2, the molar ratio of compound A, Lewis base, and solvent is 1:(1.5~2.0):(2.3~4.0); the temperature for the nucleophilic substitution reaction is 20~100℃. In S3, the molar ratio of compound B, the second catalyst, and anthraquinol is 1:(2.1~3.4):(0.8~1.2); the esterification reaction temperature is 20~100℃. In S4, the molar ratio of compound C, aminophenylboronic acid, the third catalyst, and the solvent is 1:(2.5~4.5):(0.01~0.02):(220~250); the reaction temperature is 20~100℃.

7. The flexible photosensitive polyurethane film prepared by the preparation method according to any one of claims 1-6.

8. A method for constructing microstructures on the surface of a flexible photosensitive polyurethane film, characterized in that, include: The flexible photosensitive polyurethane film of claim 7 is exposed to ultraviolet light through a photomask, and then developed with a developer to construct microstructures on its surface. The developer includes at least one of acetone, toluene, ethanol, isopropanol, dimethylformamide, tetrahydrofuran, acetonitrile, petroleum ether, dichloromethane, ethyl acetate, benzene, cyclohexane, sodium hydroxide, potassium hydroxide, sodium carbonate, hydrochloric acid, sulfuric acid, phosphoric acid, sodium chloride, potassium chloride, alkylphenol polyoxyethylene ether, fatty alcohol polyoxyethylene ether, sodium dodecyl sulfate, sodium dodecylbenzene sulfonate, hydrogen peroxide, persulfate, sodium sulfite, or sodium bisulfite.

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