Photochromic polyurethane materials and methods for their preparation, photoinitiators, coatings, optical devices and applications

Abstract

Photochromic polyurethane material and preparation method thereof, photoinitiator, paint, coating, optical device and application; the photochromic polyurethane material introduces photochromic structural units into the polyurethane material, through optimizing molecular design, the material can quickly respond and discolor under ultraviolet light irradiation, and quickly restores to the colorless state under visible light or heating conditions; in addition, the polyurethane matrix enhances the mechanical strength and chemical stability of the material, so that it has better durability in various application environments, solving the problem that the photochromic performance, mechanical performance, weather resistance and thermal stability of the existing material cannot be simultaneously compatible.

Description

Technical Field

[0001] This invention relates to the field of photochromic materials, and more particularly to a photochromic polyurethane material and its preparation method, photoinitiator, coating, coating layer, optical device and application. Background Technology

[0002] Photochromic materials are a class of functional materials that change color under ultraviolet light irradiation and are widely used in smart coatings, sensors, and optical devices. Typical photochromic molecules, such as naphthol-pyran compounds, undergo conformational changes under ultraviolet light irradiation through heterolytic cleavage of the CO bonds, causing the molecules to change from a colorless state to a colored state. When the ultraviolet light is removed or heating is applied, the molecules reclose their rings, returning to a colorless state. This reversible ring-opening and ring-closing reaction makes naphthol-pyran photochromic molecules highly promising for applications in smart coatings.

[0003] However, existing photochromic materials still face numerous challenges in practical applications. For instance, existing naphthol-pyran compounds often exhibit a gradual weakening of their photochromic response after repeated use, with prolonged light response times and insufficient depth of color change. Furthermore, existing photochromic materials suffer from insufficient mechanical properties, typically failing to maintain long-term wear resistance and stability during application, especially in dynamic environments or scenarios with significant mechanical wear, where their photochromic performance is prone to degradation. Weather resistance is also a major challenge; the color-changing ability of existing materials easily decreases or even completely fails under humid, ultraviolet-exposed, and acidic / alkaline conditions. Particularly in outdoor environments, photochromic materials require extremely high weather resistance and anti-aging properties, which are difficult to achieve with current technologies. Summary of the Invention

[0004] The purpose of this invention is to propose a photochromic polyurethane material, which introduces photochromic structural units into the polyurethane material. Through optimized molecular design, the material can respond quickly and change color under ultraviolet light irradiation, and rapidly return to a colorless state under visible light or heating conditions. In addition, the polyurethane matrix enhances the mechanical strength and chemical stability of the material, giving it better durability in various application environments.

[0005] The present invention also proposes a method for preparing a photochromic polyurethane material, which is used to prepare the above-mentioned photochromic polyurethane material.

[0006] To achieve this objective, the present invention adopts the following technical solution: A photochromic polyurethane material, with the following chemical structural formula: ; Wherein, R is a hydrocarbon group or a derivative of a hydrocarbon group; m is a natural number, m≥0; n is the degree of aggregation.

[0007] Optimally, R can be one of alkyl, alkyl derivative, aryl, aryl derivative, benzyl or benzyl derivative.

[0008] Ideally, the molecular structure can be one of the following substructures: .

[0009] A method for preparing a photochromic polyurethane material includes the following steps: S1: Weigh the compound Add solvent and stir until completely dissolved; add The compound was reacted with triethylamine at room temperature. After the reaction was complete, the organic layer was washed, the organic phase was separated, dried, and the solvent was removed to obtain the crude product. The crude product was then purified to obtain the pure target compound. ; S2: Dissolve the target compound from step S1 in a solvent, and add the diisocyanate compound dropwise under a protective gas and stirring conditions. A catalyst is added to initiate a polymerization reaction; after the reaction is complete, the solvent is removed, and the mixture is washed to remove unreacted monomers and impurities, yielding the desired product. Where R is a hydrocarbon group or a hydrocarbon derivative; m is a natural number, m≥0; and n is the degree of polymerization.

[0010] Optimizable, The synthesis method includes the following steps: S1-1: Dissolve compounds A-1 and A-2 in a solvent, stir, heat to 100-120℃, and react under a protective atmosphere; cool to room temperature, remove the solvent, and separate and purify to obtain intermediate A-3; Compound A-1 is Compound A-2 is sodium acetylene; intermediate A-3 is... ; S1-2: Dissolve intermediate A-3 in a flux, add naphthol as compound A-4, add sodium hydroxide, and react with stirring until the nucleophilic substitution reaction is complete; after the reaction, separate the organic phase, dry, filter, and remove the solvent to obtain compound A-5; compound A-5 is... ; S1-3: Dissolve compound A-5 in concentrated sulfuric acid, add concentrated nitric acid dropwise, control the reaction temperature at 0-5℃, and stir the reaction in an ice bath; after the reaction is complete, slowly pour the reaction mixture into ice water, filter and collect the precipitate, wash the precipitate to obtain intermediate A-6; intermediate A-6 is ; S1-4: Dissolve intermediate A-6 in a solvent, add a reducing agent and concentrated hydrochloric acid, and react at 30-90℃ with stirring, maintaining an acidic environment during the reaction; after the reaction is complete, remove the reducing agent, concentrate the filtrate to dryness, dissolve the concentrate in water and adjust to alkalinity, collect the precipitated product by vacuum filtration to obtain intermediate A-7; intermediate A-7 is ; S1-5: Dissolve intermediate A-7 in acid, slowly add sodium nitrite solution at 0-5℃ to form a diazonium salt; after the reaction is complete, add ice water and stir; add water, filter the product, collect the product, and wash with water until neutral to obtain... .

[0011] A photoinitiator, comprising: a photochromic polyurethane material; The photochromic polyurethane material is one of the above-mentioned photochromic polyurethane materials, or is prepared by the above-mentioned method for preparing a photochromic polyurethane material.

[0012] A coating whose raw materials include: photochromic polyurethane material; The photochromic polyurethane material is one of the above-mentioned photochromic polyurethane materials, or is prepared by the above-mentioned method for preparing a photochromic polyurethane material.

[0013] A coating comprising: photochromic polyurethane material; The photochromic polyurethane material is one of the above-mentioned photochromic polyurethane materials, or is prepared by the above-mentioned method for preparing a photochromic polyurethane material.

[0014] An optical device using photochromic polyurethane material; The photochromic polyurethane material is one of the above-mentioned photochromic polyurethane materials, or is prepared by the above-mentioned method for preparing a photochromic polyurethane material.

[0015] An application of a polymer in optical devices, wherein the polymer is a photochromic polyurethane material as described above, or is prepared by the preparation method of a photochromic polyurethane material as described above.

[0016] Compared with the prior art, one of the above technical solutions has the following beneficial effects: This solution provides a photochromic polyurethane material that incorporates photochromic structural units into the polyurethane material. Through optimized molecular design, the material can rapidly respond and change color under ultraviolet light irradiation, and quickly return to a colorless state under visible light or heating conditions. In addition, the polyurethane matrix enhances the material's mechanical strength and chemical stability, giving it better durability in various application environments. This solves the problem that existing materials cannot simultaneously possess photochromic properties, mechanical properties, weather resistance, and thermal stability. Detailed Implementation

[0017] To facilitate understanding of the present invention, a more comprehensive description is provided below. The present invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of the disclosure of the present invention. Where specific techniques or conditions are not specified in the embodiments, they are performed in accordance with techniques or conditions described in the literature in the art or according to product instructions. Reagents or instruments used, unless otherwise specified, are all conventional products that can be obtained commercially.

[0018] A photochromic polyurethane material, with the following chemical structural formula: ; Wherein, R is a hydrocarbon group or a derivative of a hydrocarbon group; m is a natural number, m≥0; n is the degree of aggregation.

[0019] This solution provides a photochromic polyurethane material that incorporates photochromic structural units into the polyurethane material. Through optimized molecular design, the material can rapidly respond and change color under ultraviolet light irradiation, and quickly return to a colorless state under visible light or heating conditions. In addition, the polyurethane matrix enhances the material's mechanical strength and chemical stability, giving it better durability in various application environments. This solves the problem that existing materials cannot simultaneously possess photochromic properties, mechanical properties, weather resistance, and thermal stability.

[0020] Optimally, R can be one of alkyl, alkyl derivative, aryl, aryl derivative, benzyl or benzyl derivative.

[0021] -R- represents one of the following: alkyl, alkyl derivative, aryl, aryl derivative, benzyl, or benzyl derivative. Examples of alkyl groups include: methylene (-CH2-), ethylene (-CH2CH2-), 1,3-propylene (-CH2CH2CH2-), 1,4-butylene (-CH2CH2CH2CH2-), 1,2-propylene (-CH2CH(CH3)-), and 1,1-propylene (-C(CH3)2-). Examples of alkyl derivatives include: 1,2-dichloroethane (ClCH2CH2Cl), and 1,3-dibromopropane (BrCH2CH2CH2B). r), 1,4-dichlorobutane (ClCH2CH2CH2CH2Cl), 1,2-dibromoethane (BrCH2CH2Br), 1,3-dichloropropane (ClCH2CH2CH2Cl), 1,4-dibromobutane (BrCH2CH2CH2CH2Br); aryl groups such as: 1,2-phenylene (-C6H4-), 1,3-phenylene (-C6H4-), 1,4-phenylene (-C6H4-), 1,2-naphthylene (-C 10 H6-, naphthalene ring at 1,2 positions), 1,4-naphthylene (-C) 10 H6-, naphthalene ring 1,4 position), 1,5-naphthylene (-C) 10 H6- (naphthalene ring at positions 1 and 5); aryl derivatives such as aryl with halogen atoms or other substituents. Benzyl derivatives such as benzyl with halogen atoms or other substituents.

[0022] Ideally, the molecular structure can be one of the following substructures: .

[0023] The solvent used in this invention refers to any solvent capable of dissolving the reactants. The role of the solvent is to achieve a uniform molecular dispersion of the reactants, i.e., the dissolution process. The dissolution process includes two steps: the diffusion (endothermic) of solute molecules (or ions) and the interaction with solvent molecules to form solvated molecules (exothermic). Based on the principle of "dissolving what resembles," polar solvents are suitable for dissolving polar compounds, and nonpolar solvents are suitable for dissolving nonpolar compounds. Those skilled in the art can select an appropriate solvent based on the polarity characteristics of the reactants.

[0024] A method for preparing a photochromic polyurethane material includes the following steps: S1: Weigh the compound Add solvent and stir until completely dissolved; add The compound was reacted with triethylamine at room temperature. After the reaction was complete, the organic layer was washed, the organic phase was separated, dried, and the solvent was removed to obtain the crude product. The crude product was then purified to obtain the pure target compound. ; The solvent for this step can be selected from one or a combination of halogenated hydrocarbon solvents (anhydrous dichloromethane, chloroform, anhydrous dichloroethane, dichloropropane, etc.), N-methylpyrrolidone, ethylene glycol ether solvents, ester solvents, etc. and The molar ratio can be 1:(0.1-10), for example 1:2, 1:2.05, 1:2.1, 1:2.2, etc.

[0025] S2: Dissolve the target compound from step S1 in a solvent, and add the diisocyanate compound dropwise under a protective gas and stirring conditions. A catalyst is added to initiate a polymerization reaction; after the reaction is complete, the solvent is removed, and the mixture is washed to remove unreacted monomers and impurities, yielding the desired product. Where R is a hydrocarbon group or a hydrocarbon derivative; m is a natural number, m≥0; and n is the degree of polymerization.

[0026] The solvent used in this step can be selected from one or a combination of halogenated hydrocarbon solvents (anhydrous dichloromethane, chloroform, anhydrous dichloroethane, dichloropropane, etc.), N-methylpyrrolidone, ethylene glycol ether solvents, ester solvents, etc. The molar ratio of the target compound to the diisocyanate compound can be (1-10):1, for example, 1:1, 1.05:1, 1.1:1, 1.2:1, etc.

[0027] The reaction equations for steps S1-S2 are as follows: .

[0028] Optimizable, The synthesis method includes the following steps: S1-1: Dissolve compounds A-1 and A-2 in a solvent, stir, heat to 100-120℃, and react under a protective atmosphere; cool to room temperature, remove the solvent, and separate and purify to obtain intermediate A-3; Compound A-1 is Compound A-2 is sodium acetylene; intermediate A-3 is... ; The solvent for this step can be selected from one or a combination of anhydrous toluene, xylene, petroleum ether, n-hexane, etc. The molar ratio of compound A-1 to compound A-2 can be 1:(0.1-10), for example 1:1, 1:1.05, 1:1.1, 1:2, etc.

[0029] S1-2: Dissolve intermediate A-3 in a flux, add naphthol as compound A-4, add sodium hydroxide, and react with stirring until the nucleophilic substitution reaction is complete; after the reaction, separate the organic phase, dry, filter, and remove the solvent to obtain compound A-5; compound A-5 is... ; The solvent used in this step can be selected from one or a combination of halogenated hydrocarbon solvents (anhydrous dichloromethane, chloroform, anhydrous dichloroethane, dichloropropane, etc.), N-methylpyrrolidone, ethylene glycol ether solvents, ester solvents, etc. The molar ratio of compound A-3 to compound A-4 can be 1:(0.1-10), for example 1:1, 1:1.05, 1:1.1, 1:2, etc.

[0030] S1-3: Dissolve compound A-5 in concentrated sulfuric acid, add concentrated nitric acid dropwise, control the reaction temperature at 0-5℃, and stir the reaction in an ice bath; after the reaction is complete, slowly pour the reaction mixture into ice water, filter and collect the precipitate, wash the precipitate to obtain intermediate A-6; intermediate A-6 is ; S1-4: Dissolve intermediate A-6 in a solvent, add a reducing agent and concentrated hydrochloric acid, and react at 30-90℃ with stirring, maintaining an acidic environment during the reaction; after the reaction is complete, remove the reducing agent, concentrate the filtrate to dryness, dissolve the concentrate in water and adjust to alkalinity, collect the precipitated product by vacuum filtration to obtain intermediate A-7; intermediate A-7 is ; The solvent for this step can be selected from one or a combination of ethanol, methanol, butanol, n-propanol, isopropanol, ethylene glycol, acetone, and diethyl ether. The reducing agent can be selected from elemental metals such as magnesium (Mg), aluminum (Al), zinc (Zn), and iron (Fe).

[0031] S1-5: Dissolve intermediate A-7 in acid, slowly add sodium nitrite solution at 0-5℃ to form a diazonium salt; after the reaction is complete, add ice water and stir; add water, filter the product, collect the product, and wash with water until neutral to obtain... .

[0032] The acid used in this step can be an acidic solution such as hydrochloric acid or sulfuric acid.

[0033] The reaction formulas for steps S1-1 to S1-5 are as follows: ; A photoinitiator, comprising: a photochromic polyurethane material; The photochromic polyurethane material is one of the above-mentioned photochromic polyurethane materials, or is prepared by the above-mentioned method for preparing a photochromic polyurethane material.

[0034] A coating whose raw materials include: photochromic polyurethane material; The photochromic polyurethane material is one of the above-mentioned photochromic polyurethane materials, or is prepared by the above-mentioned method for preparing a photochromic polyurethane material.

[0035] A coating comprising: photochromic polyurethane material; The photochromic polyurethane material is one of the above-mentioned photochromic polyurethane materials, or is prepared by the above-mentioned method for preparing a photochromic polyurethane material.

[0036] An optical device using photochromic polyurethane material; The photochromic polyurethane material is one of the above-mentioned photochromic polyurethane materials, or is prepared by the above-mentioned method for preparing a photochromic polyurethane material.

[0037] Optical devices mainly include two categories: optical elements and fiber optic devices. Optical elements encompass planar optical elements, spherical optical elements, molded glass aspherical lenses, etc.; fiber optic devices include coated fiber optic devices, collimators, acousto-optic devices, etc. Their application areas cover WSS in optical communication, coherent optical modules, 5G fronthaul optical modules, data center optical modules, as well as beam combiners and splitters for lithography machine optical systems.

[0038] An application of a polymer in optical devices, wherein the polymer is a photochromic polyurethane material as described above, or is prepared by the preparation method of a photochromic polyurethane material as described above.

[0039] Example: Example 1 - Synthesis of photochromic polyurethane material T-1: S1: In a dry three-necked flask, weigh 384.5 g of compound A-1 (2 mol) and add an appropriate amount of anhydrous toluene as solvent. Stir under nitrogen protection, and slowly add 96 g of compound A-2 (2 mol). Heat the reaction system to reflux temperature and maintain for 6 hours to ensure complete reaction. After the reaction is complete, cool to room temperature and remove the solvent from the reaction mixture using a rotary evaporator. Pour the residue into ice water and stir to precipitate a solid. Collect the product by filtration and wash repeatedly with deionized water until the filtrate is neutral. Recrystallize the crude product from anhydrous ethyl acetate to give 388.56 g of intermediate A-3, with a yield of 89%. 1 H NMR (500 MHz, CDCl3) δ 7.13 (d, J = 14.8 Hz, 2H), 7.02 (d, J = 15.0 Hz, 2H), 2.64 (s, 1H), 1.86 (s, 1H).

[0040] S2: In a dry three-necked flask, weigh 381.01 g of compound A-3 (1.75 mol) and add an appropriate amount of anhydrous toluene as a solvent. Under nitrogen protection, stir and slowly add 252.30 g of compound A-4 (1.75 mol). Heat the reaction system to reflux temperature and maintain for 5 hours to ensure complete reaction. After the reaction is complete, cool to room temperature, remove the solvent by rotary evaporation, and pour the residue into ice water while stirring to precipitate a solid. Collect the product by filtration and wash with deionized water until the filtrate is neutral. Recrystallize the crude product with anhydrous ethanol to finally obtain 482.68 g of compound A-5, with a yield of 80%.

[0041] 1 H NMR (500 MHz, CDCl3) δ 8.35 – 8.21 (m, 1H), 8.11 – 7.94 (m, 1H), 7.68 – 7.41 (m, 3H), 7.32 (dd, J = 14.9, 3.0 Hz, 1H), 7.13 (d, J = 14.8 Hz, 2H), 7.02 (d, J = 15.0 Hz, 2H), 6.76 (d, J = 21.8 Hz, 1H), 6.59 (d, J = 21.8 Hz, 1H).

[0042] S3: Dissolve A-5 (344.45 g / mol, 1.75 mol, 602.79 g) in 1000 mL of concentrated sulfuric acid, and slowly add concentrated nitric acid (2.0 equivalents) dropwise, maintaining the reaction temperature between 0 and 5 °C. After the addition is complete, continue stirring in an ice bath for 2 hours to ensure complete nitration. After the reaction is complete, slowly pour the reaction mixture into a large amount of ice water. Collect the precipitated solid by filtration and wash with cold water until neutral. Recrystallize the crude product from anhydrous ethanol to give 645.95 g of compound A-6, with a yield of 85%.

[0043] 1 H NMR (500 MHz, CDCl3) δ 9.01 (s, 2H), 8.35 – 8.24 (m, 1H), 8.08 –7.92 (m, 1H), 7.67 – 7.39 (m, 3H), 7.32 (dd, J = 14.9, 3.0 Hz, 1H), 6.80 (d, J = 21.8 Hz, 1H), 6.62 (d, J= 21.8 Hz, 1H).

[0044] S4: 651 g of compound A-6 (434 g / mol, 1.5 mol) was added to a reactor and dissolved in 1000 mL of ethanol. Iron powder (5 equivalents) and concentrated hydrochloric acid (3 equivalents) were added, and the mixture was heated and stirred at 60 °C for 5 hours. After the reaction was complete, the mixture was filtered while hot to remove insoluble iron residue. The filtrate was concentrated to dryness using a rotary evaporator. The concentrate was dissolved in water and adjusted to alkalinity with ammonia. The precipitated product was collected by vacuum filtration to obtain 472.04 g of compound A-7, with a yield of 84%.

[0045] 1 H NMR (500 MHz, CDCl3) δ 8.29 (dd, J = 7.3, 1.6 Hz, 1H), 8.02 (dt, J =7.3, 1.5 Hz, 1H), 7.61 (d, J = 7.5 Hz, 1H), 7.51 (dtd, J = 21.4, 7.5, 1.6 Hz,2H), 7.32 (dd, J = 7.5, 1.4 Hz, 1H), 6.76 (d, J = 10.8 Hz, 1H), 6.61 (d, J =10.8 Hz, 1H), 5.88 (s, 2H).

[0046] S5: Compound A-7 (374.48 g / mol, 1 mol, 374.48 g) was dissolved in 300 mL of hydrochloric acid. Sodium nitrite solution (1.1 equivalents) was added at 0–5 °C to form a diazonium salt. After the reaction was complete, ice water was added and stirring continued to generate compound A-8 containing a hydroxyl group. The resulting solid was collected by filtration, washed with water until neutral, and finally yielded 300.96 g of A-8, with a yield of 80%.

[0047] 1 H NMR (500 MHz, Chloroform ) δ 8.39 – 8.22 (m, 1H), 8.10 – 7.91 (m,1H), 7.68 – 7.21 (m, 4H), 6.93 – 6.69 (m, 3H), 6.56 (d, J = 21.8 Hz, 1H), 3.80(s, 2H).

[0048] S6: In a dry three-necked flask, 0.75 mol (282.41 g) of dihydroxy compound A-8 was weighed and dissolved in 300 mL of anhydrous dichloromethane. 0.75 mol (104.24 g) of 3-bromopropane 1-1 and 1.5 equivalent (112.5 g) were slowly added, and the mixture was stirred at room temperature for 6 hours. After the reaction was complete, the organic phase was washed with water, the organic layer was separated, and the solvent was removed by rotary evaporation. Purification by column chromatography yielded 1-2 in a yield of 367.24 g, representing a yield of 78%.

[0049] 1 H NMR (500 MHz, CDCl3) δ 8.53 – 8.12 (m, 1H), 8.12 – 7.90 (m, 1H), 7.72 – 7.13 (m, 4H), 6.94 – 6.30 (m, 4H), 4.11 (t, J = 15.1 Hz, 4H), 3.69 (t, J = 9.4 Hz, 4H), 2.03 (m, 4H), 1.44 (s, 2H).

[0050] S7: In a dry three-necked flask, 0.1 mol (49.26 g) of dihydroxy compound 1-2 was weighed and added to 150 mL of anhydrous dichloromethane, and stirred until completely dissolved. Under nitrogen protection, 0.1 mol (22.23 g) of diisocyanate derivative 1-3 was slowly added, along with 0.01 equivalent of dibutyltin (DBTDL) as a catalyst. The reaction was stirred continuously at room temperature for 24 hours to promote polymerization. After the reaction was complete, the reaction mixture was poured into excess methanol to precipitate, and filtered to obtain the crude product. The crude product was dried under vacuum to finally obtain polyurethane T-1, with a yield of 57.71 g and a yield of 82%.

[0051] 1 H NMR (500 MHz, CDCl3) δ 8.38 – 7.15 (m, 6H), 6.96 – 6.23 (m, 4H), 5.77 – 5.11 (m, 2H), 4.39 – 3.92 (m, 7H), 3.53 (t, J = 15.2 Hz, 2H), 2.92 (dd, J = 170.8, 24.8 Hz, 2H), 2.50 – 1.62 (m, 6H), 1.54 – 0.61 (m, 13H).

[0052] The reaction formula for Example 1: .

[0053] Example 2 - Synthesis of photochromic polyurethane material T-2: The basic steps of Example 2 are the same as steps S1-S7 of Example 1, except for step S8; S8: In a dry three-necked flask, 0.1 mol (49.26 g) of dihydroxy compound 1-2 and 0.1 mol (26.24 g) of diisocyanate derivative 2-1 were weighed, and dibutyltin (DBTDL) (0.5 wt%) was added as a catalyst. All substances were dissolved in 100 mL of anhydrous toluene. Under nitrogen protection, the mixture was heated to 80 °C and stirred for 12 hours to promote polymerization. After the reaction was complete, the mixture was cooled to room temperature, and the reaction solution was slowly poured into excess methanol to precipitate the polymer. The precipitated product was filtered and dried to obtain the target polyurethane T-2, with a yield of 61.25 g and a yield of 81%.

[0054] 1 H NMR (500 MHz, CDCl3) δ 8.12 (dddd, J = 13.3, 6.8, 4.8, 3.6 Hz, 2H),7.79 – 7.00 (m, 4H), 6.87 – 6.56 (m, 2H), 6.49 – 5.92 (m, 2H), 5.70 (s, 1H),5.16 – 4.37 (m, 3H), 4.21 – 3.84 (m, 6H), 3.52 (t, J = 8.7 Hz, 2H), 2.37 –1.75 (m, 12H), 1.73 – 1.25 (m, 8H), 1.11 (dt, J = 15.6, 11.8 Hz, 4H).

[0055] The reaction formula for Example 2: .

[0056] Example 3 - Synthesis of photochromic polyurethane material T-3: The basic steps of Example 3 are the same as steps S1-S7 of Example 1, except for step S8; S8: In a dry three-necked flask, 0.1 mol (49.26 g) of dihydroxy compound 1-2 and 0.1 mol (16.82 g) of diisocyanate derivative 3-1 were weighed. 200 mL of anhydrous dichloromethane was added as solvent, and dibutyltin (DBTDL, 0.05 equivalent, 0.93 g) was added as catalyst. The reaction mixture was stirred at room temperature for 6 hours under nitrogen protection. After the reaction was complete, the solvent was removed by rotary evaporation, and the crude product was purified by precipitation in methanol to obtain the target polyurethane T-3. The yield was 50.12 g, with a yield of 76%.

[0057] 1 H NMR (500 MHz, CDCl3) δ 8.40 – 7.84 (m, 3H), 7.79 – 7.15 (m, 8H), 6.75 (d, J = 1.4 Hz, 3H), 6.51 (s, 2H), 5.36 (s, 2H), 4.45 – 3.86 (m, 11H), 3.55 (t, J = 9.0 Hz, 3H), 3.31 – 3.00 (m, 6H), 2.08 (ddq, J = 29.3, 10.0, 9.1Hz, 6H), 1.77 – 1.00 (m, 12H).

[0058] The reaction formula for Example 3: .

[0059] Example 4 - Synthesis of photochromic polyurethane material T-4: The basic steps of Example 4 are the same as steps S1-S7 of Example 1, except for step S8; S8: In a dry three-necked flask, 0.1 mol (49.26 g) of dihydroxy compound 1-2 and 0.1 mol (21.03 g) of diisocyanate derivative 4-1 were weighed. 200 mL of anhydrous dichloromethane was added as solvent, and dibutyltin (DBTDL, 0.05 equivalent, 0.93 g) was added as catalyst. The reaction mixture was stirred at room temperature for 6 hours under nitrogen protection. After the reaction was complete, the solvent was removed by rotary evaporation, and the crude product was purified by precipitation in methanol to obtain the target polyurethane T-4. The final yield was 58.99 g, with a yield of 84%.

[0060] 1 H NMR (500 MHz, CDCl3) δ 8.08 (dddd, J= 7.8, 6.8, 4.9, 3.5 Hz, 2H),7.64 – 7.07 (m, 4H), 7.05 – 6.28 (m, 4H), 5.43 (s, 1H), 4.32 – 3.83 (m, 7H),3.50 (t, J = 15.0 Hz, 2H), 3.17 (t, J = 21.1 Hz, 2H), 2.06 (dp, J = 45.2, 15.1Hz, 4H), 1.77 – 0.57 (m, 17H).

[0061] The reaction formula for Example 4: .

[0062] Example 5 - Synthesis of photochromic polyurethane material T-5: The basic steps of Example 5 are the same as steps S1-S7 of Example 1, except for step S8; S8: In a dry three-necked flask, dihydroxy compound 1-2 (0.1 mol, 49.26 g) and diisocyanate derivative 5-1 (0.1 mol, 16.62 g) were weighed, and 200 mL of anhydrous dichloromethane was added as solvent, along with dibutyltin (DBTDL, 0.05 equivalent, 0.93 g) as catalyst. Under nitrogen protection, the reaction mixture was stirred at room temperature for 6 hours. After the reaction was complete, the solvent was removed using a rotary evaporator, and the crude product was precipitated in methanol. The final product, the target polyurethane T-5, was obtained by drying, with a yield of 50.93 g and a yield of 77%.

[0063] 1 H NMR (500 MHz, CDCl3) δ 8.12 (dddd, J = 13.2, 6.8, 4.8, 3.6 Hz, 2H),7.72 – 7.05 (m, 4H), 6.93 – 6.14 (m, 4H), 5.53 (s, 1H), 4.52 – 3.07 (m, 11H),2.57 – 1.09 (m, 12H).

[0064] The reaction formula for Example 5: .

[0065] Example 6 - Synthesis of photochromic polyurethane material T-6: The basic steps of Example 6 are the same as steps S1-S7 of Example 1, except for step S8; S8: In a dry three-necked flask, dihydroxy compound 1-2 (0.1 mol, 49.26 g) and diisocyanate derivative 6-1 (0.1 mol, 58.70 g) were weighed, and 200 mL of anhydrous dichloromethane was added as solvent, along with dibutyltin (DBTDL, 0.05 equivalent, 0.93 g) as catalyst. Under nitrogen protection, the reaction mixture was stirred at room temperature for 6 hours. After the reaction was complete, the solvent was removed using a rotary evaporator, and the crude product was precipitated in methanol. The final product, 88.11 g, was obtained by drying, representing a yield of 82%.

[0066] 1 H NMR (500 MHz, CDCl3) δ 8.11 (dddd, J = 7.8, 6.8, 5.0, 3.5 Hz, 2H),7.79 – 7.02 (m, 4H), 6.93 – 6.25 (m, 4H), 6.05 (s, 1H), 4.13 (ddd, J = 37.9,30.6, 14.7 Hz, 7H), 3.31 (ddd, J = 24.4, 15.3, 6.6 Hz, 6H), 2.35 – 0.13 (m, 70H).

[0067] The reaction formula for Example 6: .

[0068] Example 7 - Synthesis of photochromic polyurethane material T-7: The basic steps of Example 7 are the same as steps S1-S7 of Example 1, except for step S8; S8: In a dry three-necked flask, dihydroxy compound 1-2 (0.1 mol, 49.26 g) and diisocyanate derivative 7-1 (0.1 mol, 18.82 g) were weighed out, and 200 mL of anhydrous dichloromethane was added as solvent, along with dibutyltin (DBTDL, 0.05 equivalent, 0.93 g) as catalyst. The reaction was carried out under nitrogen protection and stirred at room temperature for 6 hours. After the reaction was complete, the solvent was removed by rotary evaporation, and the crude product was precipitated in methanol. The final product, the target polyurethane T-7, was obtained by drying, with a yield of 58.47 g and a yield of 86%.

[0069] 1H NMR (500 MHz, CDCl3) δ 8.49 – 7.75 (m, 2H), 7.75 – 7.09 (m, 7H), 7.05 (t, J = 3.0 Hz, 1H), 6.78 – 6.21 (m, 5H), 4.87 (s, 1H), 4.39 – 3.88 (m,10H), 3.51 (t, J = 15.2 Hz, 2H), 2.07 (dp, J = 45.4, 15.1 Hz, 4H).

[0070] The reaction formula for Example 7: .

[0071] Example 8 - Synthesis of photochromic polyurethane material T-8: The basic steps of Example 8 are the same as steps S1-S7 of Example 1, except for step S8; S8: In a dry three-necked flask, dihydroxy compound 1-2 (0.1 mol, 49.26 g) and diisocyanate derivative 8-1 (0.1 mol, 17.42 g) were weighed out, and 200 mL of anhydrous dichloromethane was added as solvent, along with dibutyltin (DBTDL, 0.05 equivalent, 0.93 g) as catalyst. The reaction was carried out under nitrogen protection and stirred at room temperature for 6 hours. After the reaction was complete, the solvent was removed by rotary evaporation, and the crude product was precipitated in methanol. The final product, the target polyurethane T-8, was obtained by drying, with a yield of 49.45 g and a yield of 75%.

[0072] 1 H NMR (500 MHz, CDCl3) δ 8.40 – 7.81 (m, 3H), 7.72 – 6.98 (m, 8H), 6.84 – 6.14 (m, 4H), 4.34 – 3.88 (m, 6H), 3.50 (t, J = 14.9 Hz, 2H), 2.35 –1.49 (m, 7H).

[0073] The reaction formula for Example 8: .

[0074] Example 9 - Synthesis of photochromic polyurethane material T-9: The basic steps of Example 9 are the same as steps S1-S7 of Example 1, except for step S8; S8: In a dry three-necked flask, 0.1 mol (49.26 g) of dihydroxy compound 1-2 and 0.1 mol (26.43 g) of diisocyanate derivative 9-1 were weighed, and 200 mL of anhydrous dichloromethane was added as solvent. Dibutyltin (DBTDL, 0.05 equivalent, 1.25 g) was added as catalyst. The reaction was carried out under nitrogen protection and stirred at room temperature for 6 hours to promote polymerization. After the reaction was completed, the solvent was removed by rotary evaporation, and the crude product was obtained by precipitation in methanol. After drying, the target polyurethane T-9 was obtained with a yield of 62.51 g, which was 83%.

[0075] 1 H NMR (500 MHz, CDCl3) δ 8.53 – 7.07 (m, 7H), 6.96 – 6.17 (m, 3H), 4.12 (td, J = 15.1, 10.0 Hz, 3H), 3.51 (t, J = 15.2 Hz, 1H), 2.30 – 1.78 (m,5H).

[0076] The reaction formula for Example 9: .

[0077] Example 10 - Synthesis of photochromic polyurethane material T-10: The basic steps of Example 10 are the same as steps S1-S7 of Example 1, except for step S8; S8: In a dry three-necked flask, 0.1 mol (49.26 g) of dihydroxy compound 1-2 and 0.1 mol (16.01 g) of diisocyanate derivative 10-1 were weighed, and 200 mL of anhydrous dichloromethane was added as solvent. Dibutyltin (DBTDL, 0.05 equivalent, 1.25 g) was added as catalyst. The reaction was carried out under nitrogen protection and stirred at room temperature for 6 hours to promote polymerization. After the reaction was completed, the solvent was removed by rotary evaporation, and the crude product was obtained by precipitation in methanol. After drying, the target polyurethane T-10 was obtained with a yield of 54.12 g, which was 83%.

[0078] 1 H NMR (500 MHz, CDCl3) δ 8.40 – 7.77 (m, 2H), 7.70 – 7.13 (m, 4H), 7.02 (s, 1H), 6.66 (dt, J = 21.8, 7.5 Hz, 2H), 4.12 (td, J= 15.2, 10.1 Hz, 3H), 3.51 (t, J = 15.2 Hz, 1H), 2.07 (dp, J = 45.5, 15.2 Hz, 2H).

[0079] The reaction formula for Example 10: .

[0080] Example 11 - Synthesis of photochromic polyurethane material T-11: The basic steps of Example 11 are the same as steps S1-S7 of Example 1, except for step S8; S8: In a dry three-necked flask, 0.1 mol (49.26 g) of dihydroxy compound 1-2 and 0.1 mol (17.42 g) of diisocyanate derivative 11-1 were weighed, and 200 mL of anhydrous dichloromethane was added as solvent. Dibutyltin (DBTDL, 0.05 equivalent, 1.25 g) was added as catalyst. The reaction was carried out under nitrogen protection and stirred at room temperature for 6 hours to promote polymerization. After the reaction was completed, the solvent was removed by rotary evaporation, and the crude product was obtained by precipitation in methanol. After drying, the target polyurethane T-11 was obtained with a yield of 50.00 g, which was 76%.

[0081] 1 H NMR (500 MHz, CDCl3) δ 8.62 – 7.77 (m, 3H), 7.77 – 6.15 (m, 12H), 4.12 (dt, J = 9.6, 4.8 Hz, 6H), 3.56 (t, J = 7.6 Hz, 2H), 2.57 – 1.73 (m, 7H).

[0082] The reaction formula for Example 11: .

[0083] Example 12 - Synthesis of photochromic polyurethane material T-12: The basic steps of Example 12 are the same as steps S1-S7 of Example 1, except for step S8; S8: In a dry three-necked flask, 0.1 mol (49.26 g) of dihydroxy compound 1-2 and 0.1 mol (24.43 g) of diisocyanate derivative 12-1 were weighed, and 200 mL of anhydrous dichloromethane was added as solvent. Dibutyltin (DBTDL, 0.05 equivalent, 1.25 g) was added as catalyst. The reaction was carried out under nitrogen protection and stirred at room temperature for 6 hours to promote polymerization. After the reaction was completed, the solvent was removed by rotary evaporation, and the crude product was obtained by precipitation in methanol. After drying, the target polyurethane T-12 was obtained with a yield of 60.39 g, which was 82%.

[0084] 1 H NMR (500 MHz, CDCl3) δ 8.10 (dddd, J = 7.8, 6.8, 5.0, 3.5 Hz, 2H),7.86 – 7.11 (m, 7H), 7.13 – 6.25 (m, 6H), 5.64 (s, 1H), 4.32 – 3.88 (m, 6H),3.51 (t, J = 15.0 Hz, 2H), 2.39 – 1.77 (m, 4H), 1.45 (s, 12H).

[0085] The reaction formula for Example 12: .

[0086] Example 13 - Synthesis of photochromic polyurethane material T-13: The basic steps of Example 13 are the same as steps S1-S7 of Example 1, except for step S8; S8: In a dry three-necked flask, 0.1 mol (49.26 g) of dihydroxy compound 1-2 and 0.1 mol (25.03 g) of diisocyanate derivative 13-1 were weighed, and 200 mL of anhydrous dichloromethane was added as solvent. Dibutyltin (DBTDL, 0.05 equivalent, 1.25 g) was added as catalyst. The reaction was carried out under nitrogen protection and stirred at room temperature for 6 hours to promote polymerization. After the reaction was completed, the solvent was removed by rotary evaporation, and the crude product was obtained by precipitation in methanol. After drying, the target polyurethane T-13 was obtained with a yield of 56.89 g, which was 76% of the total yield.

[0087] 1 H NMR (500 MHz, CDCl3) δ 8.57 (s, 1H), 8.29 (dd, J= 7.3, 1.6 Hz, 1H), 8.02 (dt, J = 7.3, 1.5 Hz, 1H), 7.67 – 7.20 (m, 9H), 7.10 (d, J = 7.5 Hz, 4H), 6.83 (dt, J = 22.2, 10.9 Hz, 3H), 6.48 (s, 1H), 4.26 – 3.98 (m, 6H), 3.83 (s,2H), 3.59 (t, J = 4.0 Hz, 2H), 2.08 (ddq, J = 44.0, 8.3, 4.2 Hz, 4H).

[0088] The reaction formula for Example 13: .

[0089] Example 14 - Synthesis of photochromic polyurethane material T-14: The basic steps of Example 14 are the same as steps S1-S7 of Example 1, except for step S8; S8: In a dry three-necked flask, 0.1 mol (49.26 g) of dihydroxy compound 1-2 and 0.1 mol (21.02 g) of diisocyanate derivative 14-1 were weighed, and 200 mL of anhydrous dichloromethane was added as solvent. Dibutyltin (DBTDL, 0.05 equivalent, 1.25 g) was added as catalyst. The reaction was carried out under nitrogen protection and stirred at room temperature for 6 hours to promote polymerization. After the reaction was completed, the solvent was removed by rotary evaporation, and the crude product was obtained by precipitation in methanol. After drying, the target polyurethane T-14 was obtained with a yield of 53.28 g, which was 76%.

[0090] 1 H NMR (500 MHz, CDCl3) δ 9.34 (s, 1H), 8.42 – 7.81 (m, 3H), 7.68 –7.16 (m, 8H), 7.13 – 6.29 (m, 6H), 4.12 (d, J = 10.0 Hz, 6H), 3.52 (s, 2H), 2.08 (d, J = 45.0 Hz, 4H).

[0091] The reaction formula for Example 14: .

[0092] Based on the 14 representative photochromic polyurethanes (T1-T14) synthesized in Examples 1-14 above, the following performance tests were conducted to verify the application potential of the materials. The results are shown in Table 1. The tests included: ① Photochromic performance test: Each material was dissolved to prepare a thin film coating, which was then applied to a glass substrate, ensuring uniform coating. The film was irradiated with a 365 nm ultraviolet light source, and the color change depth and color change / recovery rate were determined by ultraviolet-visible spectroscopy. The stability of the color change cycle was also evaluated.

[0093] ② Thermal stability test: Thermogravimetric analysis (TGA) was used to measure the weight loss of the samples as the temperature increased. The samples were heated in a nitrogen atmosphere, and the decomposition temperature of the material was recorded. The glass transition temperature (Tg) of the samples was measured using differential scanning calorimetry (DSC). The temperature range was set from 25 °C to 400 °C, with a heating rate of 10 °C / min, to evaluate the thermal stability of the material.

[0094] ③ Mechanical performance testing: Each material was prepared into a film of uniform thickness, and its tensile strength and elongation at break were measured using a tensile tester. The tensile speed was set to 5 mm / min, and the film was stretched until it broke to evaluate its mechanical properties.

[0095] ④ Weather resistance test: The thin film samples were subjected to accelerated aging tests in an environment with ultraviolet light, 85% humidity, and 60°C for 1000 hours. Samples were taken periodically to evaluate the retention of photochromic properties and anti-aging characteristics.

[0096] illustrate: The photochromic polyurethane materials in Examples 1-14 exhibit excellent comprehensive performance in terms of photochromic efficiency, mechanical properties, and weather resistance. In particular, their efficient color-changing response and mechanical stability make them suitable for a variety of applications such as smart coatings and optical devices.

[0097] 1. Regarding the high-efficiency photochromic performance, the photochromic time is 13-20 seconds, and the recovery time is 11-16 seconds, indicating that the photochromic material of this invention can rapidly change color under ultraviolet light irradiation and recover its original state under visible light or heating conditions. This material has a faster light response speed, higher stability, and the photochromic process is unaffected by environmental factors, exhibiting good recyclability. Simultaneously, the color change depth can reach 0.37-0.45, demonstrating excellent photochromic performance. This design solves the problems of weakened light response and reduced color change depth in traditional naphthol-pyran materials, making it particularly suitable for applications such as smart coatings and optical devices.

[0098] 2. The decomposition temperature is 285-305℃, and the Tg is 124-135℃. The decomposition temperature and Tg results indicate that it is suitable for high-temperature applications.

[0099] 3. Regarding the improvement of mechanical properties and durability, the tensile strength is 11.5-12.5 MPa and the elongation at break is 190-220%. After introducing the polyurethane matrix, the material shows a significant improvement in mechanical properties, especially in terms of elongation at break.

[0100] 4. Regarding weather resistance, the color retention rate is 80-90%. This characteristic enables the material to maintain the stability of its color change performance during long-term use, demonstrating the material's resistance to ultraviolet aging and its long-term stability in harsh environments. It is particularly suitable for applications requiring high mechanical strength, such as intelligent building coatings and exterior coatings for vehicles.

[0101] In summary, this invention combines photochromic functionality with polyurethane materials. This structure not only ensures photochromic performance but also significantly improves the material's mechanical strength, durability, and chemical stability. The material can maintain its photochromic function through multiple light exposure cycles, exhibiting a short response time and rapid recovery. This expands the application scenarios of photochromic materials and provides a novel solution for the future development of optoelectronic smart materials.

[0102] Although embodiments of the invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A photochromic polyurethane material, characterized in that, Its chemical structural formula is: ； Wherein, R is a hydrocarbon group or a derivative of a hydrocarbon group; m is a natural number, m≥0; n is the degree of aggregation.

2. The photochromic polyurethane material according to claim 1, characterized in that, R is one of alkyl, alkyl derivative, aryl, aryl derivative, benzyl or benzyl derivative.

3. The photochromic polyurethane material according to claim 1, characterized in that, The molecular structure formula is one of the following substructure formulas: 。 4. A method for preparing a photochromic polyurethane material, characterized in that, Includes the following steps: S1: Weigh the compound Add solvent and stir until completely dissolved; add The compound was reacted with triethylamine at room temperature. After the reaction was complete, the organic layer was washed, the organic phase was separated, dried, and the solvent was removed to obtain the crude product. The crude product was then purified to obtain the pure target compound. ; S2: Dissolve the target compound from step S1 in a solvent, and add the diisocyanate compound dropwise under a protective gas and stirring conditions. A catalyst is added to initiate a polymerization reaction; after the reaction is complete, the solvent is removed, and the mixture is washed to remove unreacted monomers and impurities, yielding the desired product. Where R is a hydrocarbon group or a hydrocarbon derivative; m is a natural number, m≥0; and n is the degree of polymerization.

5. The method for preparing a photochromic polyurethane material according to claim 4, characterized in that, The synthesis method includes the following steps: S1-1: Dissolve compounds A-1 and A-2 in a solvent, stir, heat to 100-120℃, and react under a protective atmosphere; cool to room temperature, remove the solvent, and separate and purify to obtain intermediate A-3; Compound A-1 is Compound A-2 is sodium acetylene; intermediate A-3 is... ; S1-2: Dissolve intermediate A-3 in a flux, add naphthol as compound A-4, add sodium hydroxide, and react with stirring until the nucleophilic substitution reaction is complete; after the reaction, separate the organic phase, dry, filter, and remove the solvent to obtain compound A-5; compound A-5 is... ; S1-3: Dissolve compound A-5 in concentrated sulfuric acid, add concentrated nitric acid dropwise, control the reaction temperature at 0-5℃, and stir the reaction in an ice bath; after the reaction is complete, slowly pour the reaction mixture into ice water, filter and collect the precipitate, wash the precipitate to obtain intermediate A-6; intermediate A-6 is ; S1-4: Dissolve intermediate A-6 in a solvent, add a reducing agent and concentrated hydrochloric acid, and react at 30-90℃ with stirring, maintaining an acidic environment during the reaction; after the reaction is complete, remove the reducing agent, concentrate the filtrate to dryness, dissolve the concentrate in water and adjust to alkalinity, collect the precipitated product by vacuum filtration to obtain intermediate A-7; intermediate A-7 is ; S1-5: Dissolve intermediate A-7 in acid, slowly add sodium nitrite solution at 0-5℃ to form a diazonium salt; after the reaction is complete, add ice water and stir; add water, filter the product, collect the product, and wash with water until neutral to obtain... .

6. A photoinitiator, characterized in that, include: Photochromic polyurethane materials; The photochromic polyurethane material is a photochromic polyurethane material according to any one of claims 1-3, or is prepared by the preparation method of a photochromic polyurethane material according to any one of claims 4-5.

7. A coating, characterized in that, Its raw materials include: photochromic polyurethane materials; The photochromic polyurethane material is a photochromic polyurethane material according to any one of claims 1-3, or is prepared by the preparation method of a photochromic polyurethane material according to any one of claims 4-5.

8. A coating, characterized in that, Its raw materials include: photochromic polyurethane materials; The photochromic polyurethane material is a photochromic polyurethane material according to any one of claims 1-3, or is prepared by the preparation method of a photochromic polyurethane material according to any one of claims 4-5.

9. An optical device, characterized in that, Use photochromic polyurethane material; The photochromic polyurethane material is a photochromic polyurethane material according to any one of claims 1-3, or is prepared by the preparation method of a photochromic polyurethane material according to any one of claims 4-5.

10. An application of a polymer in optical devices, characterized in that, The polymer is a photochromic polyurethane material according to any one of claims 1-3, or is prepared by the preparation method of a photochromic polyurethane material according to any one of claims 4-5.

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