Polyurethane material with photo-thermal self-repairing performance and preparation method and 3D printing method thereof

Abstract

The invention relates to a polyurethane material with photo-thermal self-repairing performance, the polyurethane material is prepared from diisocyanate, macromolecular dihydric alcohol, a micromolecular dihydric alcohol chain extender, a photo-thermal agent, a catalyst and a solvent, and the polyurethane material is used as a 3D printing material. When the material is used for 3D printing, the photo-thermal performance of the material is utilized, a deposition layer is irradiated with light along a printing path in the FDM printing process, so that the temperature of a previous deposition layer is increased, and the problem of rapid cooling of the previous deposition layer in the prior art is solved; the temperature of a previously deposited layer is increased, so that the self-repairing performance of the 3D printing material is activated, the interlayer bonding strength between adjacent filaments is enhanced, and finally mechanical enhancement and mechanical isotropy of an FDM printing product are achieved. The polyurethane material disclosed by the invention is beneficial to widening the practical application of FDM printed products in the engineering field.

Description

Technical Field

[0001] The present invention relates to the field of 3D printing, and more particularly to a polyurethane material with photothermal self-repairing properties, a preparation method thereof, and a 3D printing method. Background Art

[0002] 3D printing is an advanced molding technology that can directly and quickly mold three-dimensional structures with complex structural products without the help of molds, and is widely used in many fields such as automobiles, aerospace, and intelligent robots. 3D printing technology based on fused deposition modeling (FDM) has become one of the most widely used 3D printing technologies due to its advantages such as simple operation, low equipment cost, and great material compatibility. However, compared with traditional manufacturing technologies, although FDM technology can directly print products with complex structures, the mechanical properties of its printed products are relatively poor, usually significantly lower than those of products prepared based on traditional manufacturing technologies. In addition, for FDM printed products, the degree of mutual diffusion and re-entanglement of polymer chains between adjacent filament interfaces is the key to determining their mechanical properties. However, due to the rapid cooling of the previously deposited layers during FDM printing, when the newly extruded molten material is deposited on these cooled layers, it usually leads to incomplete diffusion and limited re-entanglement of polymer chains between adjacent filament interfaces. Therefore, FDM printed products ultimately exhibit weak mechanical strength and mechanical anisotropy. In particular, the mechanical strength in the direction perpendicular to the deposition layer is significantly lower than that in other directions, thus limiting the practical application of FDM printed products as fully functional components in the engineering field. Summary of the invention

[0003] In view of the technical problems faced by the above-mentioned FDM technology, the present invention provides a polyurethane material with photothermal self-healing properties, which is used to solve the technical problems of poor mechanical strength and mechanical anisotropy of printed products faced by the current FDM technology. First, a polyurethane material with self-healing properties is synthesized by molecular structure design; secondly, a photothermal agent is introduced into the self-healing polyurethane by solution blending, thereby giving the material photothermal properties, and preparing a polyurethane material with both photothermal and self-healing properties. Finally, the polyurethane material with both photothermal and self-healing properties is used as a 3D printing material, and the photothermal properties of the material are used to irradiate the deposited layer with light along the printing path during the FDM printing process to increase the temperature of the previous deposited layer, thereby solving the problem of rapid cooling of the previous deposited layer in the prior art; the temperature of the previous deposited layer is increased, thereby activating the self-healing properties of the 3D printing material, thereby enhancing the interlayer bonding strength between adjacent filaments, and ultimately achieving mechanical enhancement of the FDM printed product.

[0004] One of the purposes of the present invention is to provide a polyurethane material with photothermal self-healing properties, wherein the polyurethane material is prepared from diisocyanate, macromolecular diol, small molecule diol chain extender, photothermal agent, catalyst, and solvent; the molar ratio of the diisocyanate, the macromolecular diol, the small molecule diol chain extender, and the catalyst is 100:15-60:60-85:0.1-1. Preferably, the molar ratio of the diisocyanate, the macromolecular diol, the small molecule diol chain extender, and the catalyst is 100:15-40:65-85:0.2-0.8. The weight ratio of the total weight of the diisocyanate, the macromolecular diol, and the small molecule diol chain extender to the photothermal agent is 100:4-10; the small molecule diol chain extender is one or more of a small molecule diol chain extender containing a disulfide bond and / or a small molecule diol chain extender containing an oxime hydroxyl group, and an oxime dihydroxy chain extender. The technician can select a suitable molar ratio of the diisocyanate, the macromolecular diol, the small molecule diol chain extender, the photothermal agent, the catalyst, and the solvent according to actual needs.

[0005] In one preferred embodiment of the present invention, the diisocyanate is one or more of isophorone diisocyanate, hexamethylene diisocyanate, diphenylmethane diisocyanate, toluene diisocyanate, p-phenylene diisocyanate, 1,5-naphthalene diisocyanate, trimethylhexamethylene diisocyanate, and dicyclohexylmethane diisocyanate. The technician can select the appropriate type of diisocyanate according to actual needs.

[0006] In one preferred embodiment of the present invention, the macromolecular diol is one or more of hydroxyl-terminated polyester diol, hydroxyl-terminated polyether diol, hydroxyl-terminated polybutadiene, and polysiloxane diol; preferably, the hydroxyl-terminated polyester diol is one or more of polyadipate small molecule diol ester diol, polycarbonate diol, and polycaprolactone diol; or the hydroxyl-terminated polyether diol includes polytetramethylene ether diol and / or polypropylene oxide ether diol. The technician can select the appropriate macromolecular diol type according to actual needs.

[0007] In one preferred embodiment of the present invention, the disulfide bond-containing small molecule diol chain extender is 3,3′-dihydroxydiphenyl disulfide and / or bis(2-hydroxyethyl) disulfide; or the oxime hydroxyl-containing small molecule diol chain extender is dimethylglyoxime and / or p-benzoquinone dioxime. Technicians can select the appropriate type of small molecule diol chain extender according to actual needs.

[0008] In one preferred embodiment of the present invention, the photothermal agent is an inorganic photothermal material and / or conjugated polymer nanoparticles; preferably, the inorganic photothermal material is one or more of graphene, carbon nanotubes, and gold nanorods; or the conjugated polymer nanoparticles are polydopamine and / or polyaniline. Technicians can select the appropriate type of photothermal agent according to actual needs.

[0009] In one preferred embodiment of the present invention, the catalyst is one or more of dibutyltin dilaurate, triphenylbismuth, and triphenyltin chloride. The solvent is one or more of N,N-dimethylformamide, N,N-dimethylacetamide, tetrahydrofuran, and 1,4-dioxane. The technicians can select the appropriate catalyst and solvent type according to actual needs.

[0010] In response to the different performance requirements of the required polyurethane materials, such as mechanical strength, toughness, rheological properties, glass transition temperature, etc., technicians can choose different macromolecular diols, diisocyanates, and small molecule diol chain extenders according to actual needs; they can also control the photothermal performance by adjusting the content of the photothermal agent, and control the reaction rate by adjusting the type of catalyst and the feed ratio.

[0011] The second object of the present invention is to provide a method for preparing a polyurethane material having photothermal self-healing properties according to the first object of the present invention, the method comprising:

[0012] 1) heating the macromolecular diol to remove water from the macromolecular diol to obtain a first intermediate product;

[0013] 2) cooling the first intermediate product, and adding the diisocyanate thereto to obtain an isocyanate-terminated polyurethane prepolymer;

[0014] 3) adding the small molecule diol chain extender and the catalyst to the isocyanate-terminated polyurethane prepolymer, heating and reacting to obtain a second intermediate product;

[0015] 4) casting the second intermediate product into a mold and vacuum curing it to obtain a polyurethane material with self-repairing properties;

[0016] 5) dissolving the polyurethane material with self-repairing properties in a solvent, adding the photothermal agent, mixing evenly, and removing the solvent to obtain a polyurethane material with photothermal self-repairing properties;

[0017] The following solutions can be adopted:

[0018] 1) Add the macromolecular diol into a device equipped with condensation reflux, and stir for 2 hours under vacuum conditions at 120° C. to completely remove the water contained in the macromolecular diol, which is the first intermediate product.

[0019] 2) cooling the first intermediate product to a certain temperature, adding the diisocyanate to the first intermediate product under a nitrogen atmosphere, stirring, and reacting the two for a period of time to obtain an isocyanate-terminated polyurethane prepolymer.

[0020] 3) Under a nitrogen atmosphere, the small molecule chain extender and the catalyst are added to the isocyanate-terminated polyurethane prepolymer in step 2), heated to a certain temperature, stirred, and the viscosity of the reaction system increases to a point where it is about to climb the pole, thereby obtaining a second intermediate product.

[0021] 4) Casting the second intermediate product into a polytetrafluoroethylene (PTFE) mold and curing it in a vacuum oven to obtain a polyurethane material with self-healing properties.

[0022] 5) dissolving the polyurethane material with self-healing properties in step 4) into a solvent, adding the photothermal agent, and fully mixing under high-speed stirring, and finally removing the solvent to finally obtain a polyurethane material with photothermal self-healing properties.

[0023] In one preferred embodiment of the present invention, in step 1), the reaction temperature is 105-120°C, and the reaction time is 1.5-2h; in step 2), the reaction temperature is 50-90°C, and the reaction time is 1-2h; in step 3), the reaction temperature is 50-80°C, and the reaction time is 1-3h; in step 4), the vacuum curing temperature is 80-100°C, and the vacuum curing time is 8-12h. The technician can select the appropriate reaction time, vacuum curing time and vacuum curing temperature according to actual needs.

[0024] The third object of the present invention is to provide a 3D printing method for a polyurethane material with photothermal self-healing properties according to the first object of the present invention or a polyurethane material with photothermal self-healing properties prepared by the method according to the second object of the present invention, characterized in that:

[0025] The polyurethane material with photothermal self-repairing performance is printed by using a fused deposition modeling printer; during the printing process, near-infrared light is used to irradiate the deposited layer.

[0026] In one preferred embodiment of the present invention, the wavelength of the near-infrared light is 808-1100 nm, and the irradiation power is 0.3-1.0 W·cm -2 ; The irradiation time is 0.5 to 2 minutes. According to actual needs, technicians can adjust the irradiation power and irradiation time of near-infrared light to control the temperature of the previously deposited layer, and then obtain 3D printed products that meet the preset mechanical properties and are mechanically isotropic.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] 1. The present invention uses macromolecular diols, diisocyanates, small molecule diol chain extenders, photothermal agents, catalysts, and solvents as raw materials, designs and synthesizes a new functional polyurethane material with both photothermal and self-healing properties, and uses it as a 3D printing material. When the material is used for 3D printing, the photothermal properties of the material are utilized to irradiate the deposited layer with light along the printing path during the FDM printing process to increase the temperature of the previous deposited layer, thereby solving the problem of rapid cooling of the previous deposited layer in the prior art; the temperature of the previous deposited layer is increased, thereby activating the self-healing properties of the 3D printing material, thereby enhancing the interlayer bonding strength between adjacent filaments, and ultimately achieving mechanical enhancement and mechanical isotropy of FDM printed products. The polyurethane material of the present invention helps to broaden the practical application of FDM printed products in the field of engineering.

[0029] 2. The polyurethane material of the present invention has both photothermal and self-healing properties, and its self-healing temperature is much lower than its melting temperature and decomposition temperature. Therefore, when the photothermal property is used to activate the self-healing property of the material to improve the interlayer bonding strength of the FDM printed product, there is no need to heat the deposited layer to the melting temperature to achieve self-healing, thereby effectively avoiding damage to the printed product structure and degradation of the deposited material during the printing process.

[0030] 3. The polyurethane material with photothermal self-repairing properties of the present invention has self-healing properties, which endows the FDM printed products with self-repairing capabilities and prolongs the service life of the FDM printed products. DETAILED DESCRIPTION

[0031] The present invention is described in detail below in conjunction with specific embodiments. It is necessary to point out that the following embodiments are only used to further illustrate the present invention and cannot be understood as limiting the scope of protection of the present invention. Some non-essential improvements and adjustments made to the present invention by those skilled in the art based on the contents of the present invention still fall within the scope of protection of the present invention.

[0032] Example 1

[0033] Preparation of polyurethane material with photothermal self-healing properties for 3D printing: 0.0175 mol of polycaprolactone diol (number average molecular weight of about 2000) was added to a three-necked flask equipped with a mechanical stirrer and stirred for 2 hours under vacuum conditions at 120°C to completely remove the moisture contained in the polycaprolactone diol. Then, the reaction system was cooled to 60°C, and 0.0963 mol of diphenylmethane diisocyanate was added under a nitrogen atmosphere, and the temperature was slowly raised to 80°C for reaction for 2 hours to obtain a polyurethane prepolymer. Then, 0.0788 mol of p-benzoquinone dioxime and 0.0005 mol of dibutyltin dilaurate catalyst were added to the polyurethane prepolymer and reacted at 70°C for 2 hours. When the viscosity of the reaction system reached a certain level, the reactant was cast into a polytetrafluoroethylene (PTFE) mold and cured in a vacuum oven at 100°C for 10 hours to obtain a polyurethane material with self-healing properties. Then the cured polyurethane material is fully dissolved in 100 ml of N,N-dimethylformamide, and then 2.8 g of graphene is added and fully mixed under high-speed stirring, and finally the solvent is removed to finally obtain a polyurethane material with photothermal and self-healing properties. It should be noted that in this embodiment, the weight of the graphene is 4% of the total weight of the diisocyanate, the macromolecular diol, and the small molecule diol chain extender.

[0034] 3D printing method of polyurethane material with photothermal self-healing properties: The polyurethane material with photothermal self-healing properties is printed and formed by a FDM (fused deposition modeling) printer. The printing temperature is 180°C, the printing speed is 10mm / s, and the printing platform temperature is 60°C. During the printing process, near-infrared light with a wavelength of 808nm is used to irradiate the deposited layer along the printing path, and the irradiation power is 0.6W·cm -2 , thereby utilizing the photothermal effect of the polyurethane material to increase the temperature of the deposited layer, thereby activating the self-healing properties of the polyurethane material, and ultimately improving the bonding strength between the deposited layers.

[0035] Example 2

[0036] Preparation of polyurethane material with photothermal self-healing properties for 3D printing: 0.0193 mol of polytetramethylene ether glycol (number average molecular weight of about 2000) was added to a three-necked flask equipped with a mechanical stirrer and stirred for 2 hours under vacuum conditions at 115°C to completely remove the moisture contained in the polytetramethylene ether glycol. Then, the reaction system was cooled to 75°C, and 0.0997 mol of isophorone diisocyanate was added under a nitrogen atmosphere, and the temperature was slowly raised to 80°C for reaction for 2 hours to obtain a polyurethane prepolymer. Then, 0.0804 mol of dimethylglyoxime and 0.0003 mol of dibutyltin dilaurate catalyst were added to the polyurethane prepolymer and reacted at 90°C for 2 hours. When the viscosity of the reaction system reached a certain level, the reactant was cast into a polytetrafluoroethylene (PTFE) mold and cured in a vacuum oven at 100°C for 10 hours to finally obtain a polyurethane material with self-healing properties. Then, the cured polyurethane material is fully dissolved in 100 ml of N,N-dimethylacetamide, and then 3.5 g of carbon nanotubes are added and fully mixed under high-speed stirring, and finally the solvent is removed to finally obtain a polyurethane material with photothermal and self-healing properties. It should be noted that in this embodiment, the weight of the carbon nanotubes is 5% of the total weight of the diisocyanate, the macromolecular diol, and the small molecule diol chain extender.

[0037] 3D printing method of polyurethane material with photothermal self-healing properties: The polyurethane material with photothermal self-healing properties is printed and formed by a FDM (fused deposition modeling) printer. The printing temperature is 170°C, the printing speed is 10mm / s, and the printing platform temperature is 40°C. During the printing process, near-infrared light with a wavelength of 808nm is used to irradiate the deposited layer along the printing path, and the irradiation power is 0.6W·cm -2 , thereby utilizing the photothermal effect of the polyurethane material to increase the temperature of the deposited layer, thereby activating the self-healing properties of the polyurethane material, and ultimately improving the bonding strength between the deposited layers.

[0038] Example 3

[0039] Preparation of polyurethane material with photothermal self-healing properties for 3D printing: 0.035 mol of polytetramethylene ether glycol (number average molecular weight of about 1000) was added to a three-necked flask equipped with a mechanical stirrer and stirred for 2 hours under vacuum conditions at 115°C to completely remove the moisture contained in the polytetramethylene ether glycol. Then, the reaction system was cooled to 50°C, and 0.1046 mol of hexamethylene diisocyanate was added under a nitrogen atmosphere, and the temperature was slowly raised to 60°C for reaction for 2 hours to obtain a polyurethane prepolymer. Then, 0.0696 mol of 3,3′-dihydroxydiphenyl disulfide and 0.0003 mol of dibutyltin dilaurate catalyst were added to the polyurethane prepolymer and reacted at 80°C for 2 hours. When the viscosity of the reaction system reached a certain level, the reactant was cast into a polytetrafluoroethylene (PTFE) mold and cured in a vacuum oven at 100°C for 10 hours to finally obtain a polyurethane material with self-healing properties. Then, the cured polyurethane material is fully dissolved in 100 ml of N,N-dimethylformamide, and then 4.9 g of carbon nanotubes are added and fully mixed under high-speed stirring, and finally the solvent is removed to finally obtain a polyurethane material with photothermal and self-healing properties. It should be noted that in this embodiment, the weight of the carbon nanotubes is 5% of the total weight of the diisocyanate, the macromolecular diol, and the small molecule diol chain extender.

[0040] 3D printing method of polyurethane material with photothermal self-healing properties: The polyurethane material with photothermal self-healing properties is printed and formed by a FDM (fused deposition modeling) printer. The printing temperature is 190°C, the printing speed is 10mm / s, and the printing platform temperature is 60°C. During the printing process, near-infrared light with a wavelength of 808nm is used to irradiate the deposited layer along the printing path, and the irradiation power is 0.6W·cm -2 , thereby utilizing the photothermal effect of the polyurethane material to increase the temperature of the deposited layer, thereby activating the self-healing properties of the polyurethane material, and ultimately improving the bonding strength between the deposited layers.

[0041] Comparative Example 1

[0042] Preparation of polyurethane material with self-healing properties for 3D printing: 0.0175 mol of polycaprolactone diol (number average molecular weight of about 2000) was added to a three-necked flask equipped with a mechanical stirrer and stirred for 2 hours under vacuum conditions at 120°C to completely remove the moisture contained in the polycaprolactone diol. Then, the reaction system was cooled to 60°C, and 0.0963 mol of diphenylmethane diisocyanate was added under a nitrogen atmosphere, and the temperature was slowly raised to 80°C for reaction for 2 hours to obtain a polyurethane prepolymer. Then, 0.0788 mol of p-benzoquinone dioxime and 0.0005 mol of dibutyltin dilaurate catalyst were added to the polyurethane prepolymer and reacted at 70°C for 2 hours. When the viscosity of the reaction system reached a certain level, the reactant was cast into a polytetrafluoroethylene (PTFE) mold and cured in a vacuum oven at 100°C for 10 hours to obtain a polyurethane material with self-healing properties.

[0043] 3D printing method of polyurethane material with self-healing properties: The polyurethane material with self-healing properties is printed and formed by using an FDM (fused deposition modeling) printer. The printing temperature is 170°C, the printing speed is 10mm / s, and the printing platform temperature is 60°C. During the printing process, near-infrared light with a wavelength of 808nm is used to irradiate the deposited layer along the printing path, and the irradiation power is 0.6W·cm -2 .

[0044] The self-repairing efficiency, melting temperature, glass transition temperature, tensile strength and photothermal temperature of the polyurethane materials with photothermal self-repairing properties prepared in Examples 1 to 3 and the polyurethane materials with self-repairing properties prepared in Comparative Example 1 were tested. The polyurethane materials prepared in Examples 1 to 3 and Comparative Example 1 were made into dumbbell-shaped standard tensile specimens (70mm×4mm×2mm) and then tested. Among them, the self-repairing experiment is to use a blade to cut a scratch with a depth of about 1.5mm on the dumbbell-shaped standard tensile specimen (70mm×4mm×2mm), and then repair the sample at 100°C for 40min, and then test the tensile strength of the repaired sample, and the ratio of the tensile strength of the repaired sample to the tensile strength of the uncut sample is defined as the self-repairing efficiency. The melting temperature and glass transition temperature of the sample were tested by differential scanning calorimetry (DSC). The tensile strength of the dumbbell-shaped standard tensile specimen (70mm×4mm×2mm) was tested by a universal testing machine at a tensile rate of 100mm / s. The photothermal temperature was measured by an infrared thermometer. The test results are shown in Table 1

[0045] Table 1 Self-repairing efficiency, melting temperature, glass transition temperature, tensile strength and photothermal temperature of polyurethane materials prepared in Examples 1 to 3 and Comparative Example 1

[0046] Example 1 Example 2 Example 3 Comparative Example 1 Self-repair efficiency (100℃) / % 89.5 95.4 85.6 90.2 Melting temperature / ℃ 170 160 180 160 Glass transition temperature / ℃ -2.8 -12.5 22.4 -15.4 Tensile strength / MPa 29 27 41 24 <![CDATA[Photothermal temperature (0.6 W·cm -2 ) / ℃]]> 110 100 160 /

[0047] The tensile strength of the polyurethane materials obtained by FDM printing of Examples 1 to 3 and Comparative Example 1 (thin sheets with the same thickness as the aforementioned dumbbell-shaped standard tensile specimen, whose thickness is also 2 mm) was measured, including the tensile strength along the X-axis direction, the tensile strength along the Y-axis direction, and the tensile strength along the Z-axis direction. The tensile strength of the product was tested by a universal testing machine at a tensile rate of 100 mm / s. The test results are shown in Table 2.

[0048] From the analysis of the results in Table 2, it can be seen that compared with Comparative Example 1, the tensile strength of the products obtained by FDM printing of the polyurethane materials prepared in Examples 1 to 3 along the X-axis, Y-axis and Z-axis directions is significantly increased, indicating that the mechanical properties of the 3D printed products are improved. It can be seen that the mechanical properties of the products obtained by FDM printing of the polyurethane material with photothermal self-healing properties of the present invention are significantly improved, which effectively solves the technical defect of poor mechanical properties of current FDM printed products.

[0049] Table 2 Tensile strength of products obtained by FDM printing of polyurethane materials prepared in Examples 1 to 3 and Comparative Example 1

[0050] Example 1 Example 2 Example 3 Comparative Example 1 Tensile strength along the X-axis / MPa 28.1 26.4 40.5 19.2 Tensile strength along the Y axis / MPa 27.4 25.7 39.4 13.8 Tensile strength along Z axis / MPa 26.7 24.6 38.9 11.5

[0051] In summary, the present invention imparts both photothermal and self-healing properties to thermoplastic polyurethane 3D printing materials, and uses the photothermal effect of the material to activate the self-healing properties of the material during FDM printing, thereby effectively improving the mechanical properties of FDM printed products and achieving mechanical isotropy. The present invention effectively solves the technical defect of poor mechanical properties of current FDM printed products, and will greatly broaden the practical application of FDM printed products in the engineering field.

Claims

1. A polyurethane material with photothermal self-repairing properties, characterized in that: The polyurethane material is prepared from diisocyanate, macromolecular diol, small molecule diol chain extender, photothermal agent, catalyst and solvent; the molar ratio of the diisocyanate, the macromolecular diol, the small molecule diol chain extender and the catalyst is 100:15-60:60-85: 0.1～1； Wherein, the weight ratio of the total weight of the diisocyanate, the macromolecular diol, and the small molecule diol chain extender to the photothermal agent is 100:4-10; The small molecule diol chain extender is one or more of a small molecule diol chain extender containing a disulfide bond and / or a small molecule diol chain extender containing an oxime hydroxyl group, and an oxime dihydroxy chain extender.

2. The polyurethane material according to claim 1, characterized in that: The molar ratio of the diisocyanate, the macromolecular diol, the small molecule diol chain extender and the catalyst is 100:15-40:65-85:0.2-0.

8.

3. The polyurethane material according to claim 1, characterized in that: The diisocyanate is one or more of isophorone diisocyanate, hexamethylene diisocyanate, diphenylmethane diisocyanate, toluene diisocyanate, p-phenylene diisocyanate, 1,5-naphthalene diisocyanate, trimethylhexamethylene diisocyanate, and dicyclohexylmethane diisocyanate.

4. The polyurethane material according to claim 1, characterized in that: The macromolecular diol is one or more of hydroxyl-terminated polyester diol, hydroxyl-terminated polyether diol, hydroxyl-terminated polybutadiene, and polysiloxane diol; Preferably, The hydroxyl-terminated polyester diol is one or more of polyadipate small molecule diol ester diol, polycarbonate diol, and polycaprolactone diol; or The hydroxyl-terminated polyether diol includes polytetramethylene ether diol and / or polypropylene oxide ether diol.

5. The polyurethane material according to claim 1, characterized in that: The disulfide-bond-containing small molecule diol chain extender is 3,3′-dihydroxydiphenyl disulfide and / or bis(2-hydroxyethyl) disulfide; or The small molecule diol chain extender containing oxime hydroxyl group is diacetyl oxime and / or p-benzoquinone dioxime.

6. The polyurethane material according to claim 1, characterized in that: The photothermal agent is an inorganic photothermal material and / or conjugated polymer nanoparticles; Preferably, The inorganic photothermal material is one or more of graphene, carbon nanotubes, and gold nanorods; or The conjugated polymer nanoparticles are polydopamine and / or polyaniline.

7. The polyurethane material according to claim 1, characterized in that: The catalyst is one or more of dibutyltin dilaurate, triphenylbismuth, and triphenyltin chloride; and / or The solvent is one or more of N,N-dimethylformamide, N,N-dimethylacetamide, tetrahydrofuran, and 1,4-dioxane.

8. A method for preparing a polyurethane material having photothermal self-repairing properties as claimed in any one of claims 1 to 7, characterized in that The method comprises: 1) heating the macromolecular diol to remove water from the macromolecular diol to obtain a first intermediate product; 2) cooling the first intermediate product, and adding the diisocyanate thereto to obtain an isocyanate-terminated polyurethane prepolymer; 3) adding the small molecule diol chain extender and the catalyst to the isocyanate-terminated polyurethane prepolymer, heating and reacting to obtain a second intermediate product; 4) casting the second intermediate product into a mold and vacuum curing it to obtain a polyurethane material with self-repairing properties; 5) dissolving the polyurethane material with self-repairing properties in a solvent, adding the photothermal agent, mixing evenly, and removing the solvent to obtain a polyurethane material with photothermal self-repairing properties; Preferably, In step 1), the reaction temperature is 105-120°C and the reaction time is 1.5-2h; and / or In step 2), the reaction temperature is 50-90°C and the reaction time is 1-2h; and / or In step 3), the reaction temperature is 50-80°C and the reaction time is 1-3h; and / or In step 4), the vacuum curing temperature is 80-100° C., and the vacuum curing time is 8-12 hours.

9. A 3D printing method for the polyurethane material with photothermal self-healing properties as claimed in any one of claims 1 to 7 or the polyurethane material with photothermal self-healing properties prepared by the method as claimed in claim 8, characterized in that The 3D method includes Printing the polyurethane material with photothermal self-repairing performance by using a fused deposition modeling printer; During the printing process, near-infrared light is used to irradiate the deposited layers.

10. The method according to claim 9, characterized in that: The wavelength of the near infrared light is 808-1100nm; More preferably, the irradiation power is 808 to 965 W·cm -2 ; Irradiation time is 0.5~2min.