Flexible photosensitive polyurethane film and preparation method thereof

Abstract

The invention 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; the preparation method comprises the following steps: reacting diisocyanate, soft-segment diol and a photosensitive monomer through a one-pot method to obtain a polyurethane solution; and coating the polyurethane solution on a substrate, and drying to obtain the flexible photosensitive polyurethane film. The flexible photosensitive polyurethane film is prepared by adopting a one-step synthesis process, the preparation process is simple, and the production efficiency is improved. The flexible photosensitive polyurethane film prepared by the invention has high photosensitive performance and pattern resolution, a highly regular microstructure can be accurately constructed on the surface of the flexible photosensitive polyurethane film through photomask and ultraviolet exposure treatment, the processing technology is simple, and complex highly ordered patterns can be realized; and the microstructure on the surface can evolve along with time, so that the characteristic that the optical performance of the material surface changes along with time is endowed.

Description

Technical Field

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

[0002] In the rapidly developing field of science and technology, flexible materials are gradually becoming the key driving force for innovation in many 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 many 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 comprehensive properties, it is still a challenging task to prepare highly regular surface morphologies on the surface of polyurethane polymers. In the prior art, the microstructure of the surface of traditional polyurethane films is usually constructed by physical or chemical means, which 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 polyurethane polymers, which limits their application in fields such as high-performance optical encryption materials. Summary of the invention

[0004] The present application provides a flexible photosensitive polyurethane film and a preparation method thereof, aiming to solve the problem in the prior art that the processing technology for constructing microstructures on the surface of polyurethane films is complex and it is difficult to form highly ordered patterns.

[0005] In order to achieve the above objectives, the present application adopts the following technical solutions.

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

[0007] preparing photosensitive monomers;

[0008] A polyurethane solution is obtained by reacting diisocyanate, soft segment diol and photosensitive monomer in a one-pot process;

[0009] The polyurethane solution is coated on a substrate and dried to obtain a flexible photosensitive polyurethane film.

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

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

[0012] Preferably, the soft segment diol includes any one of 1,4-butanediol, 1,2-propylene glycol, 1,3-propylene glycol, 1,6-hexanediol, ethylene glycol adipate, 1,4-butanediol terephthalate, diethylene glycol sebacate, polyoxypropylene glycol, polyethylene glycol, polytetramethylene glycol, polycarbonate diol, polyethylene glycol, polybutylene glycol, polyethylene oxide-propylene oxide copolyether, glycerol, sorbitol or polycaprolactone diol.

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

[0014]

[0015] wherein R1, R2, R3, R4, R5, R6, and R7 are each independently selected from hydrogen, C 1～20 Aryl, C 1～20 Heterocyclic aromatic group, C 1～20 Alkyl, C 1～20 Acyl, C 1～20 Ester group, C 1～20 Ketone, C 1～20 Aldehyde, C 1～20 Alkoxy, C 1～20 Any of aryloxy groups.

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

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

[0018] S2, adding compound A and Lewis base into a solvent and mixing until a homogeneous phase is obtained, and then adding an acid compound to carry out a nucleophilic substitution reaction to obtain compound B;

[0019] S3, dissolving compound B and anthracene alcohol in a solvent, and causing an esterification reaction under the action of a second catalyst to obtain compound C;

[0020] S4, in an acidic environment, dispersing compound C and aminophenylboronic acid in a solvent, and reacting under the action of a third catalyst to obtain a photosensitive monomer.

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

[0022]

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

[0024]

[0025] wherein R1, R2, R3, R4, R5, R6, and R7 are each independently selected from hydrogen, C 1～20 Aryl, C 1～20 Heterocyclic aromatic group, C 1～20 Alkyl, C 1～20 Acyl, C 1～20 Ester group, C 1～20 Ketone, C 1～20 Aldehyde, C 1～20 Alkoxy, C 1～20 Any of the aryloxy groups;

[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, and 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 ether;

[0032] and / or,

[0033] The second catalyst comprises 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-carbonyldiimidazole, dicyclohexylcarbodiimide, trifluoroacetic acid, 2-(7-azabenzotriazole)-N,N,N',N'-tetramethyluronium hexafluorophosphate, tributylthiourea, benzotriazol-1-yl-oxytripyrrolidinophosphine hexafluorophosphate, diethylphosphinoethyltriethoxysilane, acetamide or 1-hydroxybenzotriazole;

[0034] and / or,

[0035] The third catalyst includes any one of ruthenium (II) diphenylphosphine dichloride, ruthenium (II) diphenylphosphine tris 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 composite catalyst, palladium-nickel composite 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, cyclopentane, N-methyl-2-pyrrolidone, m-cresol, xylenol, benzene, toluene, xylene, N-vinyl-2-pyrrolidone, butyrolactone, and 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°C;

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

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

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

[0042] The second aspect of the present application provides a flexible photosensitive polyurethane film prepared by the above preparation method.

[0043] The third aspect of the present application provides a method for constructing a microstructure on the surface of a flexible photosensitive polyurethane film, comprising:

[0044] The flexible photosensitive polyurethane film is exposed to ultraviolet light through a photomask, and then developed with a developer to construct a microstructure on its surface;

[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 dodecylbenzene sulfonate, hydrogen peroxide, persulfate, sodium sulfite or sodium bisulfite.

[0046] Compared with the prior art, the beneficial effects of this application are:

[0047] The present application adopts a one-step synthesis process to prepare a flexible photosensitive polyurethane film, which has a simple preparation process, reduces the complexity and uncertainty of the production process, and improves production efficiency.

[0048] The flexible photosensitive polyurethane film prepared in the present application has high photosensitivity and pattern resolution. Through photomask and ultraviolet exposure treatment, a highly regular microstructure can be accurately constructed on its surface. Not only is the processing technology simple, but also complex highly ordered patterns can be achieved. The microstructure on the surface of the photosensitive polyurethane film of the present application can evolve over time, giving the material surface optical properties that change over time, broadening its application field. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments recorded in the present application, and for ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0050] Figure 1 This is the morphology of the photomask under a microscope.

[0051] Figure 2 This is a microscope morphology image of the flexible photosensitive polyurethane film prepared in Example 1 after being exposed to ultraviolet light through a photomask;

[0052] Figure 3 This is a microscope morphology image of the flexible photosensitive polyurethane film prepared in Example 3 after being exposed to ultraviolet light through a photomask;

[0053] Figure 4 This is a microscope morphology image of the flexible photosensitive polyurethane film prepared in Example 4 after ultraviolet exposure through a photomask. DETAILED DESCRIPTION

[0054] The technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0055] In the following description of this embodiment, the terms "include", "comprising", "having" and "containing" are all open terms, meaning including but not limited to.

[0056] In the following description of this embodiment, the term "and / or" is used to describe the association relationship of associated objects, indicating that there may be three relationships. For example, A and / or B can represent: A exists alone, B exists alone, and A and B exist at the same time. A and B can be singular or plural. The character " / " generally indicates that the associated objects before and after are in an "or" relationship.

[0057] In the following description of this embodiment, the term "at least one" refers to one or more, and "plurality" refers to two or more. "At least one of the following" or similar expressions refers to any combination of these items, including any combination of single items or plural items. For example, "at least one of a, b or c", or "at least one of a, b and c", can all represent: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, c can be single or multiple, respectively.

[0058] The terms used in the embodiments of the present application are only for the purpose of describing specific embodiments, and are not intended to limit the present application. The singular forms "a", "an" and "the" used in the embodiments of the present application and the appended claims are also intended to include plural forms, unless the context clearly indicates other meanings.

[0059] Those skilled in the art should understand that in the following description of the embodiments of the present application, the order of serial numbers does not mean the order of execution, some or all of the steps can be executed in parallel or sequentially, and the execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0060] Those skilled in the art will appreciate that the numerical ranges in the embodiments of the present application are to be construed as specifically disclosing each intermediate value between the upper and lower limits of the scope. Each smaller range between the intermediate value in any stated value or stated range and any other stated value or intermediate value in the described range is also included in the present application. The upper and lower limits of these smaller ranges may be independently included or excluded in the scope.

[0061] Unless otherwise specified, the technical / scientific terms used herein have the same meanings as those generally understood by those skilled in the art to which this application belongs. Although this application only describes preferred methods and materials, any methods and materials similar or equivalent to those described herein may also be used in the implementation or testing of this application. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials related to the documents. In the event of a conflict with any incorporated document, the content of this specification shall prevail.

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

[0063] preparing photosensitive monomers;

[0064] A polyurethane solution is obtained by reacting diisocyanate, soft segment diol and photosensitive monomer in a one-pot process;

[0065] The polyurethane solution is coated on a substrate, and after vacuum drying, it is peeled off from the substrate to obtain a flexible photosensitive polyurethane film.

[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 reaction is 20-100° C. The substrate can be a sheet material with a smooth surface such as a glass sheet or a plastic sheet.

[0067] In the present application, the soft segment diol includes any one of 1,4-butanediol, 1,2-propylene glycol, 1,3-propylene glycol, 1,6-hexanediol, ethylene glycol adipate, 1,4-butanediol terephthalate, diethylene glycol sebacate, polyoxypropylene glycol, polyethylene glycol, polytetramethylene glycol, polycarbonate diol, polyethylene glycol, polybutylene glycol, polyethylene oxide-propylene oxide copolyether, glycerol, sorbitol or polycaprolactone diol; 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, and R7 are each independently selected from hydrogen, C 1～20 Aryl, C 1～20 Heterocyclic aromatic group, C 1～20 Alkyl, C 1～20 Acyl, C 1～20 Ester group, C 1～20 Ketone, C 1～20 Aldehyde, C1～20 Alkoxy, C 1～20 Any of aryloxy groups.

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

[0072] S1, dispersing a halogenated phenol and a halogenated ester in a solvent, carrying out a nucleophilic substitution reaction at 20-100°C under the action of a first catalyst, separating the reaction product by column chromatography to obtain a compound A; wherein, preferably, the molar ratio of the halogenated phenol, the halogenated ester and the first catalyst is 1:(0.5-1.5):(1.5-2.5).

[0073] Wherein, the chemical structure of the halogenated phenol is shown in formula (2):

[0074]

[0075] Wherein, R1, R2, and R3 are each independently selected from hydrogen, C 1～20 Aryl, C 1～20 Heterocyclic aromatic group, C 1～20 Alkyl, C 1～20 Acyl, C 1～20 Ester group, C 1～20 Ketone, C 1～20 Aldehyde, C 1～20 Alkoxy, C 1～20 In the embodiments of the present application, preferably R1, R2, and R3 are all hydrogen.

[0076] Specifically, 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.

[0077] 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;

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

[0079] S2, adding compound A and Lewis base into a solvent and mixing until homogeneous, then adding an acid compound to carry out a nucleophilic substitution reaction at 20-100°C, and filtering the reaction product by vacuum filtration to obtain compound B; wherein the preferred 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 anthracene alcohol in a solvent, causing an esterification reaction under the action of a second catalyst, and washing the reaction product with acid, drying it, and separating it by column chromatography to obtain compound C; wherein the molar ratio of compound B, the second catalyst and anthracene alcohol 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-dimethylaminopyridine, 1-ethyl-(3-dimethylaminopropyl)carbodiimide, 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride, N-hydroxysuccinimide, N,N-carbonyldiimidazole, dicyclohexylcarbodiimide, trifluoroacetic acid, 2-(7-azabenzotriazole)-N,N,N',N'-tetramethyluronium hexafluorophosphate, tributylthiourea, benzotriazole-1-yl-oxytripyrrolidinophosphine hexafluorophosphate, diethylphosphorylethyltriethoxysilane, acetamide or 1-hydroxybenzotriazole.

[0084] S4, in an acidic environment, dispersing compound C and aminophenylboronic acid in a solvent, reacting at 20-100° C. under the action of a third catalyst, removing water and carbon dioxide in the reaction system with potassium carbonate, collecting the solid phase of the reaction product by rotary evaporation, and then separating by column chromatography to obtain a photosensitive monomer. 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).

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

[0086]

[0087] Wherein R4, R5, R6, R7 are each independently selected from hydrogen, C 1～20 Aryl, C 1～20 Heterocyclic aromatic group, C 1～20 Alkyl, C 1～20 Acyl, C 1～20 Ester group, C 1～20 Ketone, C 1～20 Aldehyde, C 1～20 Alkoxy, C 1～20 Any of aryloxy groups.

[0088] The third catalyst includes any one of ruthenium (II) diphenylphosphine dichloride, ruthenium (II) diphenylphosphine tris 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 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 a simple preparation process, reduces the complexity and uncertainty of the production process, and improves production efficiency.

[0090] The flexible photosensitive polyurethane film prepared in the present application has high photosensitivity and pattern resolution. Through photomask and ultraviolet exposure treatment, a highly regular microstructure can be accurately constructed on its surface. Not only is the processing technology simple, but also complex and highly ordered patterns can be achieved.

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

[0092] The flexible photosensitive polyurethane film is exposed to ultraviolet light through a photomask, and then developed with a developer to construct a microstructure on its surface. Specifically, the exposed portion undergoes a cross-linking reaction to generate a polymer insoluble in the developer, and the developer is used to dissolve and remove the unexposed portion of the flexible photosensitive polyurethane film, thereby presenting a desired pattern.

[0093] 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.

[0094] The microstructure on the surface of the photosensitive polyurethane film of the present application can evolve over time, giving the material surface the characteristic of optical properties changing over time, thereby broadening its application areas.

[0095] The present application is further described below by way of examples.

[0096] Example 1

[0097] This embodiment provides a method for preparing a photosensitive monomer and a photosensitive polyurethane film, comprising:

[0098] S1, add 0.0256 mol of ethyl 4-bromobutyrate and 0.0256 mol of dibromophenol into a flask, add 50 ml of acetone and 0.0513 mol of potassium carbonate, remove water, and seal. Heat the mixture to 70°C, condense and reflux for 24 hours to react. After the reaction is completed, cool to room temperature, and separate by rotary evaporation and column chromatography to obtain 0.01977 mol of compound A;

[0099] S2, add 0.0362 mol of sodium hydroxide, 0.01977 mol of compound A, and add 0.03 mol of methanol and 0.03 mol of water into a beaker until the mixture is almost homogeneous, add hydrochloric acid to the product obtained after alkaline hydrolysis, react at 70°C, and filter under reduced pressure to obtain 0.0445 mol of compound B, which is then dissolved in dichloromethane to prepare a solution;

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

[0101] S4, take 0.00494 mol of compound C, add tetrahydrofuran thereto and perform rotary evaporation, then add 0.0147 mol of 4-aminophenylborate 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 (potassium carbonate is used to remove water and carbon dioxide in the reaction system), reflux at 70°C for 10 h under the protection of nitrogen, perform rotary evaporation again, add dichloromethane for column chromatography separation, and perform rotary evaporation again to obtain 0.0035 mol of photosensitive monomer.

[0102] S5, add 2 mol of isophorone diisocyanate and 1 mol of polytetrahydrofuran (molecular weight 1000) to 1 mol of photosensitive monomer, and heat to 70°C for 24 hours using a one-pot method. After the reaction is completed, take 200 μL of the obtained polyurethane solution and evenly apply it on a glass slide, place it at 60°C for 2 hours, and then put it in a vacuum oven at 60°C to dry, to obtain a flexible photosensitive polyurethane film.

[0103] The preparation process of Example 1 is as follows:

[0104]

[0105] The flexible photosensitive polyurethane film was peeled off from the glass sheet, and exposed to ultraviolet light with a wavelength of 365nm for 5s close to the photomask, and then placed in a mixed developer of tetrahydrofuran and ethanol for development. The morphology of the photomask under a microscope is shown in FIG. Figure 1 As shown in Figure 2, regular micron stripes can be formed on the surface of the film after development, such as Figure 2 shown.

[0106] Example 2

[0107] In Example 2, steps S1 to S4 of preparing the photosensitive monomer are the same as those in Example 1;

[0108] In S5, the amount of polytetrahydrofuran (molecular weight 1000) was changed to 1.6 mol, 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, add 0.0917mol of 1-ethyl-(3-dimethylaminopropyl)carbodiimide, 0.0089mol of 4-dimethylaminopyridine, 0.0475mol of anthracene alcohol and 0.0445mol of compound B to 1.24mol of chloroform, and stir to react for three days. After the reaction is completed, 0.4mol of 1mol / L hydrochloric acid is added to the reaction product three times, and then potassium carbonate solution is added in turn to remove hydrochloric acid, and potassium carbonate solid is removed to obtain a clear and transparent solution. The product is determined by thin layer chromatography, and compound C is separated by column chromatography;

[0112] S4, add tetrahydrofuran to compound C and perform rotary evaporation, then add 0.0147 mol of 4-aminophenylborate 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, reflux at 70°C for 10 h under the protection of nitrogen, perform rotary evaporation again, add dichloromethane for column chromatography separation, and perform rotary evaporation again to obtain 0.0035 mol of photosensitive monomer.

[0113] S5, add 2 mol of isophorone diisocyanate and 1 mol of 1,4-butanediol to 1 mol of photosensitive monomer, and heat to 70°C for 24 hours using a one-pot method. After the reaction is completed, take 200 μL of the obtained polyurethane solution and evenly apply it on a glass slide, place it at 60°C for 2 hours, and then dry it in a vacuum oven at 60°C to obtain a flexible photosensitive polyurethane film.

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

[0115]

[0116] The flexible photosensitive polyurethane film was peeled off from the glass sheet, and exposed to ultraviolet light with a wavelength of 365nm for 5s close to the photomask. Then, it was placed in a mixed developer of tetrahydrofuran and ethanol for development. It can be observed that regular micron stripes can be formed on the surface of the film, such as Figure 3 shown.

[0117] Example 4

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

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

[0120] S4, add tetrahydrofuran to compound C and perform rotary evaporation, then add 0.0147 mol of 4-aminophenylborate 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, reflux at 70°C for 10 h under the protection of nitrogen, perform rotary evaporation again, add dichloromethane for column chromatography separation, and perform rotary evaporation again to obtain 0.00366 mol of photosensitive monomer.

[0121] S5, add 2 mol of hexamethylene diisocyanate and 1 mol of polytetrahydrofuran (molecular weight 1000) to 1 mol of photosensitive monomer, and heat to 70°C for 24 hours using a one-pot method. After the reaction is completed, take 200 μL of the obtained polyurethane solution and evenly apply it on a glass sheet, place it at 60°C for 2 hours, and then dry it in a vacuum oven at 60°C to obtain a flexible photosensitive polyurethane film.

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

[0123]

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

[0125] from Figure 2 , Figure 3 and Figure 4 It can be seen that the method of constructing microstructures on the surface of a flexible photosensitive polyurethane film in the present application can successfully construct highly regular microstructures on the surface of a flexible photosensitive polyurethane film. These three regular microstructures further verify the reliability and repeatability of the method for preparing a flexible photosensitive polyurethane film in the present application, provide flexibility for adjusting the synthesis formula to meet different application requirements, and are beneficial to improving the optical properties of polyurethane films and their application potential in the fields of optical encryption.

[0126] Although the present application has been described in detail in general terms and in specific embodiments in this specification, it is obvious to those skilled in the art that some modifications or improvements may be made to the present application. Therefore, these modifications or improvements made without departing from the spirit of the present application are within the scope of protection claimed in the present application.

Claims

1. A method for preparing a flexible photosensitive polyurethane film, characterized in that: include: preparing photosensitive monomers; A polyurethane solution is obtained by reacting diisocyanate, soft segment diol and photosensitive monomer in a one-pot process; The polyurethane solution is coated on a substrate and dried to obtain a flexible photosensitive polyurethane film.

2. The preparation method according to claim 1, characterized in that: The molar ratio of the diisocyanate, the soft segment diol and the photosensitive monomer is 2:(0.2-2.0):(0.1-1.8); The temperature of the one-pot reaction is 20-100°C.

3. The preparation method according to claim 1, characterized in that: The soft segment diol includes any one of 1,4-butanediol, 1,2-propylene glycol, 1,3-propylene glycol, 1,6-hexanediol, ethylene glycol adipate, 1,4-butanediol terephthalate, diethylene glycol sebacate, polyoxypropylene glycol, polyethylene glycol, polytetramethylene glycol, polycarbonate diol, polyethylene glycol, polybutylene glycol, 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 photosensitive monomer is shown in formula (1): wherein R1, R2, R3, R4, R5, R6, and R7 are each independently selected from hydrogen, C 1～20 Aryl, C 1～20 Heterocyclic aromatic group, C 1～20 Alkyl, C 1～20 Acyl, C 1～20 Ester group, C 1～20 Ketone, C 1～20 Aldehyde, C 1～20 Alkoxy, C 1～20 Any of aryloxy groups.

5. The preparation method according to claim 4, characterized in that: The photosensitive monomer is prepared by the following method: S1, dispersing a halogenated phenol and a halogenated ester in a solvent, and performing a nucleophilic substitution reaction under the action of a first catalyst to obtain a compound A; S2, adding compound A and Lewis base into a solvent and mixing until a homogeneous phase is obtained, and then adding an acid compound to carry out a nucleophilic substitution reaction to obtain compound B; S3, dissolving compound B and anthracene alcohol in a solvent, and causing an esterification reaction under the action of a second catalyst to obtain compound C; S4, in an acidic environment, dispersing compound C and aminophenylboronic acid in a solvent, and reacting under the action of a third catalyst to obtain a photosensitive monomer.

6. The preparation method according to claim 5, characterized in that The chemical structure of the halogenated phenol is shown in formula (2): The chemical structure of the aminophenylboronic acid is shown in formula (3): wherein R1, R2, R3, R4, R5, R6, and R7 are each independently selected from hydrogen, C 1～20 Aryl, C 1～20 Heterocyclic aromatic group, C 1～20 Alkyl, C 1～20 Acyl, C 1～20 Ester group, C 1～20 Ketone, C 1～20 Aldehyde, C 1～20 Alkoxy, C 1～20 Any of the aryloxy groups; 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.

7. The preparation method according to claim 5, characterized in that 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; 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 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 ether; and / or, The second catalyst comprises 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-carbonyldiimidazole, dicyclohexylcarbodiimide, trifluoroacetic acid, 2-(7-azabenzotriazole)-N,N,N',N'-tetramethyluronium hexafluorophosphate, tributylthiourea, benzotriazol-1-yl-oxytripyrrolidinophosphine hexafluorophosphate, diethylphosphinoethyltriethoxysilane, acetamide or 1-hydroxybenzotriazole; and / or, The third catalyst includes any one of ruthenium (II) diphenylphosphine dichloride, ruthenium (II) diphenylphosphine tris 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 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, cyclopentane, N-methyl-2-pyrrolidone, m-cresol, xylenol, benzene, toluene, xylene, N-vinyl-2-pyrrolidone, butyrolactone, and butyl acetate.

8. The preparation method according to claim 5, characterized in that 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°C; In S2, the molar ratio of compound A, Lewis base and solvent is 1:(1.5-2.0):(2.3-4.0); the temperature of the nucleophilic substitution reaction is 20-100°C; In S3, the molar ratio of compound B, the second catalyst and anthracene alcohol is 1:(2.1-3.4):(0.8-1.2); the temperature of the esterification reaction is 20-100°C; The molar ratio of compound C, aminophenylboronic acid, the third catalyst and the solvent in S4 is 1:(2.5-4.5):(0.01-0.02):(220-250); the reaction temperature is 20-100°C.

9. A flexible photosensitive polyurethane film prepared by the preparation method according to any one of claims 1 to 8.

10. A method for constructing a microstructure on the surface of a flexible photosensitive polyurethane film, characterized in that: include: The flexible photosensitive polyurethane film of claim 9 is exposed to ultraviolet light through a photomask and then developed with a developer to construct a microstructure 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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