High-flexibility bio-based polyurethane fluorescent material capable of being self-repaired at room temperature and preparation method of high-flexibility bio-based polyurethane fluorescent material

Abstract

The invention discloses a high-flexibility bio-based polyurethane fluorescent material capable of being self-repaired at room temperature and a preparation method of the high-flexibility bio-based polyurethane fluorescent material, and belongs to the technical field of polyurethane materials. The preparation method comprises the following steps: generating a prepolymer from diisocyanate and polypropylene carbonate glycol under the action of a catalyst; carrying out chain extension reaction by taking dimethylglyoxime as a chain extender to generate a polyurethane material PUDMG containing ketoxime bonds; after PUDMG is dissolved, the PUDMG and a mixture of terbium nitrate hexahydrate and europium nitrate hexahydrate are subjected to a coordination reaction, and finally a target product is prepared. By introducing a dimethylglyoxime chain extender, a dynamic ketoxime bond is constructed in a polymer network, and the room-temperature efficient self-repairing of the material is realized; meanwhile, dimethylglyoxime provides effective coordination sites for Tb < 3 + > and Eu < 3 + >, and the dimethylglyoxime, the Tb < 3 + > and the Eu < 3 + > have a synergistic effect, so that the material is endowed with strong fluorescence performance, and meanwhile, the mechanical property and the self-repairing efficiency are further enhanced. The material is simple in preparation method and has a wide application prospect in the fields of flexible electronic devices and anti-counterfeiting.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of polyurethane materials, and particularly relates to a room-temperature self-repairable high-flexibility bio-based polyurethane fluorescent material and a preparation method thereof. BACKGROUND

[0002] With the improvement of environmental awareness, green, degradable, self-repairable materials are attracting attention, especially in electronic devices and packaging materials, the application of flexible devices is increasing. Traditional self-repairable materials have the problems of low repair efficiency and single repair mechanism, which cannot meet the actual application requirements. At the same time, the problem of electronic waste is becoming increasingly serious, which promotes the development of degradable materials. The introduction of degradable, room-temperature self-repairable polyurethane flexible materials can prolong the service life, reduce waste, and reduce the environmental burden. Rare earth luminescent materials have high color purity and strong light absorption capacity, but their compatibility with polymers is poor, so ligands need to be introduced to improve the compatibility and enhance the luminescent performance.

[0003] In addition, the self-repairable polyurethane in the prior art mostly introduces new structural groups to improve its performance. As a result, the synthesis process is complex, the cost is increased, and the repair conditions are limited, for example, Chinese Patent Application CN202510742241.1 discloses a sunlight-responsive high-strength self-repairable polyurethane material and a preparation method thereof, which belongs to the technical field of self-repairable materials. It is obtained by coordinating a polyurethane containing an azothiazole structure with metal ions in a certain proportion. The polyurethane containing an azothiazole structure is prepared by stirring diisocyanate, diol containing an azothiazole structure, long-chain diol, and aminobenzenesulfonic acid in N,N-dimethylformamide at room temperature for 5 hours. By introducing the photoactive azothiazole structure into the polyurethane, the azothiazole structure forms a reversible metal coordination bond with the metal ions, realizing the rapid sunlight-responsive self-repair of the polyurethane material.

[0004] Therefore, it is of great significance to develop a bio-based polyurethane fluorescent material that can realize rapid self-repair at room temperature, has strong flexibility, and is environmentally friendly, has excellent luminescent performance, and has good degradability. SUMMARY

[0005] The present application provides a room-temperature self-repairable high-flexibility bio-based polyurethane fluorescent material and a preparation method thereof, which overcomes the difficulty that the self-repairing performance of the prior art cannot be compatible with the mechanical performance, and introduces degradable and ultraviolet luminescent performance without changing the mechanical performance. It is a green material with good ductility, and the method is simple, low in cost, and has a wide application prospect.

[0006] To achieve the above technical purposes, the technical scheme adopted by the present application is as follows: A method for preparing a room-temperature self-repairable high-flexibility bio-based polyurethane fluorescent material, comprising the following steps: (1) Put diisocyanate and polyester polyol into a container, add catalyst under inert gas protection, and stir and heat to react to obtain a polyurethane prepolymer; (2) Add a chain extender to a solvent, stir until uniform, then drop into the polyurethane prepolymer obtained in step (1), and continue to stir to react to obtain a viscous liquid product A; (3) Pour the viscous liquid product A obtained into a mold, vacuum heat and dry to obtain a transparent repairable and degradable polyurethane flexible material PUDMG; (4) Dissolve the polyurethane flexible material PUDMG obtained using an organic solvent, add nitric acid rare earth element hexahydrate, heat and stir to obtain a viscous liquid product B, and constant temperature dry the product B to obtain the target product, a room-temperature self-repairable high-flexibility bio-based polyurethane fluorescent material.

[0007] Preferably, the diisocyanate in step (1) is any one or more of isophorone diisocyanate IPDI, toluene diisocyanate TDI, hexamethylene diisocyanate HDI, and diphenyl methane diisocyanate MDI, the polyester polyol is polypropylene carbonate diol with a molecular weight of 2500, and the catalyst is one or more of dibutyl tin dilaurate, stannous octoate, and dibutyl tin diacetate.

[0008] More preferably, the solid-liquid ratio of diisocyanate, polyester polyol, and catalyst in step (1) is (3-4) g:(10) g:150 μL; the inert gas is nitrogen or argon, the reaction temperature is 70-80℃, the reaction time is 2-3 hours, and the stirring speed is controlled at 200-400 r / min.

[0009] Preferably, the chain extender in step (2) is butanedione monoxime, and the solvent is one or more of N,N dimethylformamide, N,N dimethylacetamide, toluene, and dimethyl carbonate; the solid-liquid ratio of the chain extender and the solvent is 1.393 g:10 mL, the use amount ratio of the chain extender to diisocyanate is 1.393 g:(3-4) g; the continuous stirring reaction time is 2-4 hours, the reaction temperature is 70-80℃, and the stirring speed is 200-400 r / min.

[0010] Preferably, the heating temperature range for vacuum heat drying in step (3) is 70-85℃, and the drying time is 48-72 hours.

[0011] Preferably, in step (4), the solid-liquid ratio of the polyurethane flexible material PUDMG, the organic solvent, and the rare earth nitrate hexahydrate is 5 g:30 mL:0.79 g, the organic solvent is chloroform, the rare earth nitrate hexahydrate is terbium nitrate hexahydrate and europium nitrate hexahydrate, the mass ratio of the two is (0.11-9):1, the temperature of heating and stirring is 30°C, the stirring time is 1-2 hours, and the stirring speed is 400-600 rpm.

[0012] Preferably, in step (4), the heating temperature for constant-temperature drying of the product B is 30-40°C, and the drying time is 6-8 hours.

[0013] A polyurethane fluorescent material prepared by a preparation method of a room-temperature self-repairable high-flexibility bio-based polyurethane fluorescent material.

[0014] The polyurethane fluorescent material prepared by the preparation method of the room-temperature self-repairable high-flexibility bio-based polyurethane fluorescent material is applied to anti-counterfeiting and flexible devices.

[0015] Advantages: The application prepares a high-flexibility bio-based polyurethane fluorescent material with room-temperature self-repairing characteristics. The core breakthrough of the material is that butanedione oxime is introduced as a chain extender to build a ketone oxime dynamic chemical bond in the polyurethane molecular chain, which greatly strengthens the self-repairing function of the material on the basis of maintaining the original good mechanical properties of the material. Test data show that the introduced ketone oxime bond can reversibly break and recombine efficiently at room temperature, so that the material has excellent self-repairing quality. In addition, butanedione oxime also forms a large number of coordination sites in the molecular chain, which can be stably coordinated with rare earth ions Tb and Eu. This unique molecular structure improves the compatibility and dispersibility of the material compared with traditional rare earth-doped polymers. The application uses terbium nitrate (Tb) and europium nitrate (Eu) hexahydrate as the source of rare earth ions to achieve the ideal fusion of rare earth ions and the polymer matrix. It is found that the use of butanedione oxime chain extender and the synergistic effect of Tb 3+ and Eu 3+ two kinds of rare earth ions in the material system produce a significant synergistic effect, which not only enhances the fluorescence performance, but more importantly, jointly improves the mechanical properties and self-repairing properties of the material. In addition, the material can emit color-adjustable fluorescence when excited by ultraviolet light, which provides more possibilities for the functional expansion of the material. By optimizing the formula and process parameters, the outstanding contradiction between the mechanical properties and self-repairing properties of traditional self-repairing materials is effectively solved, so that the material has a wide application prospect in flexible electronics, intelligent sensing, biomedicine, and other fields. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1The infrared spectrum of the synthesis process of the transparent repairable degradable polyurethane flexible material PUDMG of the present application, wherein (a) corresponds to step (1) to obtain a polyurethane prepolymer, (b) corresponds to step (2) to obtain a viscous liquid product A, (c) corresponds to step (3) to obtain the transparent repairable degradable polyurethane flexible material PUDMG; Figure 2 The stress-strain curve diagram of the sample of Example 1 of the present application after being cut and repaired at different times; Figure 3 The electron microscope diagram of the sample of Example 1 of the present application after being scratched and repaired at different times; Figure 4 The electron microscope diagram of the sample of Comparative Examples 3-5 after being scratched and repaired for 24 hours; Figure 5 The physical sample diagram of the present application, wherein A0 is the physical diagram of the high-flexibility bio-based polyurethane fluorescent material under sunlight, and A1-A9 are the physical diagrams of Examples 1-9 of the present application under ultraviolet light. DETAILED DESCRIPTION

[0017] The technical solutions of the present application will be further described below in conjunction with specific embodiments, but are not limited thereto.

[0018] Example 1 A preparation method of a room-temperature self-repairable high-flexibility bio-based polyurethane fluorescent material, comprising the following steps: (1) Put 3.56 g of diisocyanate and 10 g of polyester polyol into a container, add 150 μL of catalyst under inert gas protection, and stir and heat to react to obtain a polyurethane prepolymer; (2) Add 1.393 g of chain extender to 10 mL of solvent, stir uniformly, and then drop into the polyurethane prepolymer obtained in step (1), and continue to stir to react to obtain a viscous liquid product A; (3) Pour the obtained viscous liquid product A into a mold, vacuum heat and dry to obtain a transparent repairable degradable polyurethane flexible material PUDMG; (4) Take 5 g of the obtained polyurethane flexible material PUDMG, dissolve it with 30 mL of organic solvent, add 0.79 g of dilute nitric acid rare earth hexahydrate, heat and stir to obtain a viscous liquid product B, and then constant-temperature dry the product B to obtain the target product, a room-temperature self-repairable high-flexibility bio-based polyurethane fluorescent material.

[0019] The PUDMG obtained in steps (1)-(3) is subjected to infrared spectrum test, FTIR test: the infrared curve of the polymer film is tested by using the attenuated total reflection mode, the scanning range is 4 000~600 cm -1 , and the scanning number is 32 times. The test diagram is analyzed as Figure 1shown, (a) to (c) 2262 cm -1 The complete disappearance of the -NCO (isocyanate) peak indicates that the isocyanate groups are completely reacted, 1740 cm -1 The presence of the C=O (carbonate) peak throughout the reaction process proves that the backbone structure (PPCD) remains intact, 1530 cm -1 The N-H (carbamate) peak appears early and gradually increases from (b) to (c), indicating that the chain extension reaction further increases the density of carbamate bonds, confirming the formation of the carbamate structure and the chain extension process, (b) to (c) 902 cm -1 The appearance and retention of the N-O peak prove the chemical incorporation of the chain extender. From the infrared characterization figure, it can be proved that the polyurethane flexible material is successfully synthesized here.

[0020] In step (1), the diisocyanate is isophorone diisocyanate IPDI, the polyester polyol is polypropylene carbonate diol with a molecular weight of 2500, and the catalyst is dibutyltin dilaurate.

[0021] In step (1), the inert gas is nitrogen, the reaction temperature is 73°C, the reaction time is 3 hours, and the stirring speed is controlled at 300 revolutions per minute.

[0022] In step (2), the chain extender is butanedione monoxime, and the solvent is N,N-dimethylformamide; the continuous stirring reaction time is 4 hours, the reaction temperature is 73°C, and the stirring speed is 300 r / min.

[0023] In step (3), the heating temperature range for vacuum heating drying is 70°C, and the drying time is 72 hours.

[0024] In step (4), the organic solvent is chloroform; the rare earth nitrate hexahydrate is terbium nitrate hexahydrate and europium nitrate hexahydrate, with a mass ratio of 9:1; the heating and stirring temperature is 30°C, the stirring time is 2 hours, and the stirring speed is 500 revolutions per minute, so that the rare earth metal elements fully coordinate with the polyurethane.

[0025] In step (4), the heating temperature range for constant temperature drying of product B is 40°C, and the drying time is 8 hours.

[0026] Example 2 A method for preparing a room temperature self-repairable high flexibility bio-based polyurethane fluorescent material, comprising the following steps: (1) Put 4g diisocyanate and 10g polyester polyol into a container, add 150μL catalyst under inert gas protection, and stir and heat to obtain a polyurethane prepolymer; (2) 1.393 g chain extender was added to 10 mL solvent, and after stirring uniformly, it was added dropwise to the polyurethane prepolymer obtained in step (1), and the stirring reaction was continued to obtain viscous liquid product A; (3) The viscous liquid product A obtained was poured into a mold, and after vacuum heating and drying, transparent repairable and degradable polyurethane flexible material PUDMG was obtained; (4) 5 g of the polyurethane flexible material PUDMG obtained was dissolved using 30 mL of organic solvent, 0.79 g of rare earth nitrate hexahydrate was added, and after heating and stirring, viscous liquid product B was obtained. After constant temperature drying of product B, the target product room temperature self-repairable high flexibility bio-based polyurethane fluorescent material was obtained.

[0027] In step (1), the diisocyanate is toluene diisocyanate TDI, the polyester polyol is polypropylene carbonate diol with a molecular weight of 2500, and the catalyst is stannous octoate.

[0028] In step (1), the inert gas is argon, the reaction temperature is 80°C, the reaction time is 2 hours, and the stirring speed is controlled at 200 rpm.

[0029] In step (2), the chain extender is butanedione monoxime, and the solvent is N,N-dimethylacetamide; the continuous stirring reaction time is 2 hours, the reaction temperature is 80°C, and the stirring speed is 200 rpm.

[0030] In step (3), the heating temperature range for vacuum heating and drying is 85°C, and the drying time is 48 hours.

[0031] In step (4), the organic solvent is chloroform; the rare earth nitrate hexahydrate is terbium nitrate hexahydrate and europium nitrate hexahydrate, with a mass ratio of 8:2; the heating and stirring temperature is 30°C, the stirring time is 1 hour, and the stirring speed is 400 rpm.

[0032] In step (4), the heating temperature range for constant temperature drying of product B is 30°C, and the drying time is 6 hours.

[0033] Example 3 A method for preparing a room temperature self-repairable high flexibility bio-based polyurethane fluorescent material, comprising the following steps: (1) 3 g of diisocyanate and 10 g of polyester polyol were placed in a container, and 150 μL of catalyst was added under inert gas protection, and the stirring and heating reaction was carried out to obtain a polyurethane prepolymer; (2) 1.393 g of chain extender was added to 10 mL of solvent, and after stirring uniformly, it was added dropwise to the polyurethane prepolymer obtained in step (1), and the stirring reaction was continued to obtain viscous liquid product A; (3) Pour the obtained viscous liquid product A into a mold, and vacuum heat drying to obtain a transparent repairable and degradable polyurethane flexible material PUDMG; (4) Take 5 g of the obtained polyurethane flexible material PUDMG, dissolve it in 30 mL of an organic solvent, add 0.79 g of rare earth nitrate hexahydrate, and heat and stir to obtain a viscous liquid product B. After constant temperature drying, the target product, a room temperature self-repairable high flexibility bio-based polyurethane fluorescent material, is obtained.

[0034] In step (1), the diisocyanate is hexamethylene diisocyanate HDI, the polyester polyol is polypropylene carbonate diol with a molecular weight of 2500, and the catalyst is dibutyl tin diacetate.

[0035] In step (1), the inert gas is nitrogen, the reaction temperature is 70°C, the reaction time is 2.5 hours, and the stirring speed is controlled at 400 rpm.

[0036] In step (2), the chain extender is butanedione monoxime, and the solvent is toluene and dimethyl carbonate. The continuous stirring reaction time is 3 hours, the reaction temperature is 70°C, and the stirring speed is 400 rpm.

[0037] In step (3), the vacuum heat drying temperature range is 80°C, and the drying time is 60 hours.

[0038] In step (4), the organic solvent is chloroform, the rare earth nitrate hexahydrate is terbium nitrate hexahydrate and europium nitrate hexahydrate, and the mass ratio of the two is 7:3. The heating and stirring temperature is 30°C, the stirring time is 1 hour, and the stirring speed is 600 rpm.

[0039] In step (4), the heating temperature range for constant temperature drying of product B is 40°C, and the drying time is 6 hours.

[0040] Example 4 A method for preparing a room temperature self-repairable high flexibility bio-based polyurethane fluorescent material, comprising the following steps: (1) Put 3.56 g of diisocyanate and 10 g of polyester polyol in a container, add 150 μL of catalyst under inert gas protection, and stir and heat to obtain a polyurethane prepolymer; (2) Add 1.393 g of chain extender to 10 mL of solvent, stir uniformly, and then add the polyurethane prepolymer obtained in step (1) dropwise, continue to stir to obtain a viscous liquid product A; (3) Pour the obtained viscous liquid product A into a mold, and vacuum heat drying to obtain a transparent repairable and degradable polyurethane flexible material PUDMG; (4) 5 g of the obtained polyurethane flexible material PUDMG is dissolved in 30 mL of an organic solvent, 0.79 g of rare earth nitrate hexahydrate is added, and after heating and stirring, a viscous liquid product B is obtained. After constant temperature drying of the product B, the target product, a room temperature self-repairable high flexibility bio-based polyurethane fluorescent material, is obtained.

[0041] In step (1), the diisocyanate is isophorone diisocyanate MDI, the polyester polyol is polypropylene carbonate diol with a molecular weight of 2500, and the catalyst is dibutyl tin dilaurate.

[0042] In step (1), the inert gas is argon, the reaction temperature is 80°C, the reaction time is 2 hours, and the stirring speed is controlled at 200 rpm.

[0043] In step (2), the chain extender is butanedione oxime, and the solvent is dimethyl carbonate; the continuous stirring reaction time is 4 hours, the reaction temperature is 80°C, and the stirring speed is 200 rpm.

[0044] In step (3), the heating temperature range for vacuum heating drying is 70°C, and the drying time is 72 hours.

[0045] In step (4), the organic solvent is chloroform; the rare earth nitrate hexahydrate is terbium nitrate hexahydrate and europium nitrate hexahydrate, with a mass ratio of 6:4; the heating and stirring temperature is 30°C, the stirring time is 1 hour, and the stirring speed is 400 rpm.

[0046] In step (4), the heating temperature range for constant temperature drying of the product B is 30°C, and the drying time is 8 hours.

[0047] Example 5 The process steps of this example are the same as those of Example 1, the only difference being that the amount ratio of the two elements in the rare earth nitrate hexahydrate is changed, i.e., the rare earth nitrate hexahydrate is terbium nitrate hexahydrate and europium nitrate hexahydrate, with a mass ratio of 5:5.

[0048] Example 6 The process steps of this example are the same as those of Example 1, the only difference being that the amount ratio of the two elements in the rare earth nitrate hexahydrate is changed, i.e., the rare earth nitrate hexahydrate is terbium nitrate hexahydrate and europium nitrate hexahydrate, with a mass ratio of 4:6.

[0049] Example 7 The process steps of this example are the same as those of Example 1, the only difference being that the amount ratio of the two elements in the rare earth nitrate hexahydrate is changed, i.e., the rare earth nitrate hexahydrate is terbium nitrate hexahydrate and europium nitrate hexahydrate, with a mass ratio of 3:7.

[0050] Example 8 The process steps of this example are the same as Example 1, the only difference is that the mass ratio of two elements in the rare earth nitrate hexahydrate is changed, that is, the rare earth nitrate hexahydrate is terbium nitrate hexahydrate and europium nitrate hexahydrate, and the mass ratio of the two is 2:8.

[0051] Example 9 The process steps of this example are the same as Example 1, the only difference is that the mass ratio of two elements in the rare earth nitrate hexahydrate is changed, that is, the rare earth nitrate hexahydrate is terbium nitrate hexahydrate and europium nitrate hexahydrate, and the mass ratio of the two is 1:9.

[0052] Comparative Example 1 The process steps of this example are the same as Example 1, the only difference is that butanedione monoxime is not used as a chain extender, that is, the chain extender in step (2) is replaced with 1,4-butanediol (BDO) in the same number of moles as butanedione monoxime (i.e. 1.081 g).

[0053] A method for preparing a polyurethane material, comprising the following steps: (1) Put 3.56 g of diisocyanate and 10 g of polyester polyol into a container, add 150 μL of catalyst under inert gas protection, and stir and heat to react to obtain a polyurethane prepolymer; (2) Add 1.081 g of chain extender to 10 mL of solvent, stir until uniform, then drop into the polyurethane prepolymer obtained in step (1), continue to stir to react to obtain a viscous liquid product A; (3) Pour the obtained viscous liquid product A into a mold, dry under vacuum heating to obtain a transparent polyurethane material; (4) Take 5 g of the obtained polyurethane material, dissolve it with 30 mL of organic solvent, add 0.79 g of rare earth nitrate hexahydrate, heat and stir to obtain a viscous liquid product B, and dry the product B at constant temperature to obtain the target product polyurethane material.

[0054] The chain extender in step (2) is 1,4-butanediol (BDO).

[0055] Comparative Example 2 The process steps of this example are the same as Example 1, the only difference is that butanedione monoxime is not used as a chain extender, that is, the chain extender in step (2) is replaced with adipic acid dihydrazide (ADH) in the same number of moles as butanedione monoxime (i.e. 1.315 g).

[0056] A method for preparing a polyurethane material, comprising the following steps: (1) Put 3.56 g of diisocyanate and 10 g of polyester polyol into a container, add 150 μL of catalyst under inert gas protection, and stir and heat to react to obtain a polyurethane prepolymer; (2) 1.315 g chain extender was added into 10 mL solvent, after stirring evenly, it was added dropwise into the polyurethane prepolymer obtained in step (1), and the stirring reaction was continued to obtain viscous liquid product A; (3) The viscous liquid product A obtained was poured into a mold, and after vacuum heating and drying, a transparent polyurethane material was obtained; (4) 5 g of the polyurethane material obtained was dissolved using 30 mL of organic solvent, 0.79 g of rare earth nitrate hexahydrate was added, and after heating and stirring, viscous liquid product B was obtained. After constant temperature drying of product B, the target product polyurethane material was obtained.

[0057] The chain extender in step (2) is adipic acid dihydrazide (ADH).

[0058] Comparative Example 3 The process steps of this comparative example are the same as Example 1, the only difference is that rare earth nitrate hexahydrate is not used. That is: A method for preparing a polyurethane material, comprising the following steps: (1) 3.56 g of diisocyanate and 10 g of polyester polyol were placed in a container, 150 μL of catalyst was added under inert gas protection, and the stirring and heating reaction was carried out to obtain a polyurethane prepolymer; (2) 1.393 g of chain extender was added into 10 mL solvent, after stirring evenly, it was added dropwise into the polyurethane prepolymer obtained in step (1), and the stirring reaction was continued to obtain viscous liquid product A; (3) The viscous liquid product A obtained was poured into a mold, and after vacuum heating and drying, a transparent polyurethane material was obtained; (4) 5 g of the polyurethane material obtained was dissolved using 30 mL of organic solvent, 0.79 g of rare earth nitrate hexahydrate was added, and after heating and stirring, viscous liquid product B was obtained. After constant temperature drying of product B, the target product polyurethane material was obtained.

[0059] Comparative Example 4 The process steps of this comparative example are the same as Example 1, the only difference is that only terbium nitrate is used in the rare earth nitrate hexahydrate. That is: A method for preparing a polyurethane material, comprising the following steps: (1) 3.56 g of diisocyanate and 10 g of polyester polyol were placed in a container, 150 μL of catalyst was added under inert gas protection, and the stirring and heating reaction was carried out to obtain a polyurethane prepolymer; (2) 1.393 g of chain extender was added into 10 mL solvent, after stirring evenly, it was added dropwise into the polyurethane prepolymer obtained in step (1), and the stirring reaction was continued to obtain viscous liquid product A; (3) The viscous liquid product A obtained was poured into a mold, and after vacuum heating and drying, a transparent polyurethane material was obtained; (4) Take 5 g of the obtained polyurethane flexible material, dissolve it in 30 mL of an organic solvent, add 0.79 g of rare earth nitrate hexahydrate, and after heating and stirring, obtain a viscous liquid product B. After constant temperature drying of the product B, the target product polyurethane material is obtained.

[0060] The rare earth nitrate hexahydrate is terbium nitrate hexahydrate.

[0061] Comparative Example 5 The process steps of this comparative example are the same as Example 1, the only difference is that only europium nitrate hexahydrate is used in the rare earth nitrate hexahydrate. That is: A method for preparing a polyurethane material, comprising the following steps: (1) Put 3.56 g of diisocyanate and 10 g of polyester polyol into a container, add 150 μL of catalyst under inert gas protection, and stir and heat to react to obtain a polyurethane prepolymer; (2) Add 1.393 g of chain extender to 10 mL of solvent, stir uniformly, and then add the polyurethane prepolymer obtained in step (1) dropwise, continue to stir and react to obtain a viscous liquid product A; (3) Pour the obtained viscous liquid product A into a mold, and after vacuum heating and drying, a polyurethane flexible material is obtained; (4) Take 5 g of the obtained polyurethane flexible material, dissolve it in 30 mL of an organic solvent, add 0.79 g of rare earth nitrate hexahydrate, and after heating and stirring, obtain a viscous liquid product B. After constant temperature drying of the product B, the target product polyurethane material is obtained.

[0062] The rare earth nitrate hexahydrate is terbium nitrate hexahydrate.

[0063] Comparative Example 6 The steps are the same as Example 1, and the prior art is referred to, the only difference is that a conventional chain extender is used, and a rare earth element is doped by physical mixing, that is: The chain extender in step (2) is equimolar 1,4-butanediol (BDO), instead of butanedione oxime; Step (4) is modified: Take 5 g of the obtained PUDMG, dissolve it in 30 mL of chloroform, add 0.79 g of terbium nitrate hexahydrate and europium nitrate hexahydrate (mass ratio 9:1), stir at 500 rpm at room temperature for 0.5 hours (only physical mixing, no coordination reaction), and then constant temperature drying.

[0064] Performance test Mechanical property test: The mechanical properties and reworkability of DCPUN were studied by UC2868A universal electronic tensile testing machine produced by Chilong Measurement and Control Technology Co., Ltd. The dumbbell-shaped samples were prepared according to the standard "Measurement of Tensile Properties of Plastic Films and Sheeting" (ASTM D-882) for testing, and the tensile rate was 20 mm / min.

[0065] Scratch repair test: First, a scalpel was used to gently scratch the surface of the sample, and the scratch was observed under an optical microscope at 40 times magnification. After different repair times at room temperature, the scratch was observed again. Under UV irradiation, the fluorescence effect was observed.

[0066] Mechanical property repair test: First, a scalpel was used to cut the standard tensile sample; then, the cutting surface was gently pushed and touched; then, the joint sample was repaired at room temperature for 24 h; finally, the repaired sample was tested by a tensile testing machine, and the room temperature self-repairing performance of the material was quantitatively evaluated. The sample size was the same as that of the mechanical property test. The healing efficiency was defined as the ratio of the tensile strength of the sample after healing to the tensile strength before cutting. All performance tests were repeated five times, and the results were averaged.

[0067] Table 1 Performance test results

[0068] From Table 1, we can see that the materials of Examples 1 to 9 all have high healing efficiency and good mechanical properties. Example 4 has a healing efficiency of 96.1%, showing that the material has excellent self-repairing ability at room temperature. In contrast, the performance of Comparative Examples 1 to 6 is significantly reduced, especially Comparative Examples 1, 2 and 6, which have a healing efficiency of less than 12%, almost no repair effect, indicating that the synergistic effect of butanedione monoxime as a chain extender and nitric acid rare element hexahydrate is crucial to the performance of the material. In addition, the results of Comparative Examples 3 to 5 further prove that the simultaneous use of terbium nitrate and europium nitrate is extremely important for improving the self-repairing performance of the material. This shows that the introduction of rare elements by chemical coordination can significantly enhance the functionality of the material, while simple physical mixing cannot achieve the same effect. Taking Example 1 sample as an example, the stress-strain curve after different repair times (Figure Figure 2 ), due to the damage to the molecular chain after shearing, the tensile properties cannot be completely restored, and as the repair time increases, the self-repairing effect of the sheared polyurethane material improves, and after 24 hours of repair, the mechanical properties can reach more than 90% of those before shearing, proving that the material has excellent self-repairing properties. The self-repairing phenomenon of the material after scratching and repairing at room temperature was observed by electron microscope, and the results are shown in Figure Figures 3-4As shown, it can be obviously seen that the scratch of the material of Example 1 gradually disappears with the extension of time, which is consistent with the stretching effect after shearing, further demonstrating that the material has strong self-repairing ability. The self-repairing ability of Comparative Examples 3-5 (after 24 h of repair) is obviously weakened. Comparative Examples 1-2 and Comparative Example 6 have almost no self-repairing ability, and the change is small, so the figure is omitted.

[0069] It should be noted that the above examples are only part of the preferred modes of implementing the present application, but not all. Obviously, all other examples obtained by those skilled in the art based on the above examples of the present application without creative labor shall belong to the scope of protection of the present application.

Claims

1. A process for the preparation of room temperature self-healable high flexible bio-based polyurethane fluorescent material, characterized in that, Comprising the following steps: (1) Put the diisocyanate and polyester polyol into a container, add catalyst under inert gas protection, and stir and heat to react to obtain a polyurethane prepolymer; (2) Add the chain extender to the solvent, stir until uniform, then drop into the polyurethane prepolymer obtained in step (1), continue to stir to obtain a viscous liquid product A; (3) Pour the viscous liquid product A into a mold, vacuum heat and dry to obtain a transparent repairable and degradable polyurethane flexible material PUDMG; (4) Dissolve the polyurethane flexible material PUDMG obtained in step (1) with an organic solvent, add rare earth nitrate hexahydrate, heat and stir to obtain a viscous liquid product B, and then constant temperature dry to obtain the target product room temperature self-repairable high flexibility bio-based polyurethane fluorescent material.

2. The process for the preparation of room temperature self-healable high flexible bio-based polyurethane fluorescent material as claimed in claim 1, wherein, The diisocyanate in step (1) is any one or more of isophorone diisocyanate IPDI, toluene diisocyanate TDI, hexamethylene diisocyanate HDI and diphenyl methane diisocyanate MDI, the polyester polyol is polypropylene carbonate glycol with a molecular weight of 2500, and the catalyst is one or more of dibutyltin dilaurate, stannous octoate and dibutyltin diacetate.

3. The process for the preparation of room temperature self-repairable high flexible bio-based polyurethane fluorescent material as claimed in claim 2, wherein, The solid-liquid ratio of diisocyanate, polyester polyol and catalyst in step (1) is (3-4) g: (10) g: 150 μL; the inert gas is nitrogen or argon, the reaction temperature is 70-80℃, the reaction time is 2-3 hours, and the stirring speed is controlled at 200-400 r / min.

4. The process for the preparation of room temperature self-healable high flexible bio-based polyurethane fluorescent material as claimed in claim 1, wherein, The chain extender in step (2) is butanedione monoxime, and the solvent is one or more of N,N dimethylformamide, N,N dimethylacetamide, toluene and dimethyl carbonate; the solid-liquid ratio of the chain extender and the solvent is 1.393 g: 10 mL, and the use amount ratio of the chain extender to diisocyanate is 1.393 g: (3-4) g; the continuous stirring reaction time is 2-4 hours, the reaction temperature is 70-80℃, and the stirring speed is 200-400 r / min.

5. The process for the preparation of room temperature self-healable high flexible bio-based polyurethane fluorescent material as claimed in claim 1, wherein, The heating temperature range for vacuum heat drying in step (3) is 70-85℃, and the drying time is 48-72 hours.

6. The process for the preparation of room temperature self-healable high flexible bio-based polyurethane fluorescent material as claimed in claim 1, wherein, The solid-liquid ratio of polyurethane flexible material PUDMG, organic solvent and rare earth nitrate hexahydrate in step (4) is 5 g: 30 mL: 0.79 g, the organic solvent is chloroform, and the rare earth nitrate hexahydrate is terbium nitrate hexahydrate and europium nitrate hexahydrate, with a mass ratio of (0.11-9): 1; the heating and stirring temperature is 30℃, the stirring time is 1-2 hours, and the stirring speed is 400-600 r / min.

7. The process for the preparation of room temperature self-healable high flexible bio-based polyurethane fluorescent material as claimed in claim 1, wherein, The heating temperature range for constant temperature drying of product B in step (4) is 30-40℃, and the drying time is 6-8 hours.

8. A polyurethane fluorescent material prepared by the preparation method of the room temperature self-repairable high flexibility bio-based polyurethane fluorescent material according to any one of claims 1-7.

9. Application of the polyurethane fluorescent material prepared by the preparation method of the room temperature self-repairable high flexibility bio-based polyurethane fluorescent material according to any one of claims 1-7 in anti-counterfeiting and flexible devices.

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