Self-repairing polyurethane material, and preparation method therefor and use thereof

Abstract

Disclosed in the present invention are a self-repairing polyurethane material, and a preparation method therefor and the use thereof. The self-repairing polyurethane material comprises the following components in parts by weight: 93-99 parts of a TPU resin, 1-5 parts of UPy-NCO, 0.1-0.5 parts of nano Fe3O4 particles, 0.2-0.5 parts of an antioxidant and 0.2-0.5 parts of a lubricant. The self-repairing polyurethane material of the present invention maintains a relatively high initial tensile strength, also has a self-repairing efficiency reaching up to 99.3%, and greatly reduces the occurrence probability of a crazing problem. A material synthesis method is simple, and the self-repairing polyurethane material can be widely applied in the fields of aerospace, electronic products, industry, transportation, etc.

Description

A self-repairing polyurethane material and its preparation method and application Technical Field

[0001] The present invention relates to the technical field of polymer materials, and in particular to a self-repairing polyurethane material and a preparation method and application thereof. Background Art

[0002] Polyurethane (PU) is a class of elastomeric polymers with high flexibility and durability, produced through the addition polymerization of polyols and isocyanates. However, traditional PU is susceptible to mechanical or chemical damage during processing, transportation, and use, resulting in cracks and fissures, which reduces the material's service life and poses safety risks. Therefore, by introducing self-healing properties, the service life and recyclability of PU can be greatly improved.

[0003] Self-healing materials can be divided into externally assisted self-healing and intrinsic self-healing, depending on whether or not additional repair agents are required. Externally assisted self-healing, due to the limited amount of repair agents, cannot repair multiple or large damage. Intrinsic self-healing does not require the addition of additional repair agents. It primarily utilizes the dynamic, reversible covalent or non-covalent bonds within the material's internal structure to complete self-healing at the fracture site, thereby repairing the damage. Because the reaction is reversible, multiple repairs are possible. Currently, intrinsic self-healing TPUs are primarily focused on nanofiller-enhanced self-healing TPUs, self-healing TPUs designed with special molecular structures, and self-healing TPUs with controlled microphase separation.

[0004] Although traditional self-healing materials have high repair efficiency, they have problems such as uncontrollable molecular structure, complex operation process and insufficient strength data. Summary of the Invention

[0005] In response to the problems of complex operation process, low mechanical properties and silver streaks in the self-repairing materials in the prior art, the present invention proposes a self-repairing polyurethane material and its preparation method and application.

[0006] The present invention provides a self-repairing polyurethane material, which comprises the following components in parts by weight:

[0007] Furthermore, the TPU resin is a thermoplastic polyester TPU with a Shore A hardness of 70 to 90, preferably 72 to 85 (Shore A hardness test standard GB / T-2411-2008).

[0008] The melt flow rate of the TPU resin is 5 to 60 g / 10 min (200° C. / 5 kg), and the melt flow rate test standard is ISO 1133-2006.

[0009] Furthermore, the structural formula of the UPy-NCO is shown below:

[0010] The synthesis reaction of UPy-NCO is shown in the figure below:

[0011] The present invention introduces functionalized 2-ureido-4(1H)-6-methylpyrimidone (UPy) into the side chain of polyester TPU through modification technology. The four hydrogen bonds between the UPy side groups interact as a hyperbranched crosslinker, thereby improving the mechanical properties of the TPU elastomer. At the same time, the plasticizer effect of the side chain enables it to have efficient self-healing ability in a thermal environment.

[0012] Furthermore, the particle size D of the nano Fe3O4 particles is 50 The thickness is 10 to 120 nm, preferably 20 to 90 nm, as determined by SEM scanning electron microscopy.

[0013] The nano-Fe3O4 particles described in the present invention can be obtained commercially or homemade. Those skilled in the art can conventionally select a preparation method for nano-Fe3O4 particles, such as chemical coprecipitation, hydrothermal method, microemulsion method, sol-gel method, etc.

[0014] The optional preparation method of nano Fe3O4 particles is as follows: weigh 0.3-2.7g FeCl3·6H2O and 1.1-18.9g sodium oleate (C 17 H 33 COONa) was dissolved in 30 mL of ethylene glycol and magnetically stirred at room temperature for 2 h to form a uniformly mixed orange-yellow solution. The mixture was added to a 50 mL polytetrafluoroethylene-lined reactor and sealed. The reactor was placed in a constant temperature forced air drying oven at 200°C for 24 h. After the reactor was naturally cooled to room temperature, the product was ultrasonically cleaned several times with anhydrous ethanol and then dried in a vacuum drying oven at 80°C.

[0015] An optional method for preparing nano-Fe3O4 particles can also be: weigh about 3.0 to 27 g of FeCl3·6H2O and about 1.2 to 10 g of FeCl2·4H2O, ultrasonically disperse them in 100 mL of deionized water, add about 65 to 700 μL of hydrazine hydrate after they are completely dissolved, add 10 to 80 mL of NH3·H2O after uniform dispersion, and ultrasonically obtain the particles for about 10 minutes. The mixture is poured into a reaction vessel, heated to 70°C in a water bath, mechanically stirred and kept warm for 1.5 hours under an N2 atmosphere, and then precipitated, washed, and dried to obtain the particles; but the present invention is not limited thereto.

[0016] Introducing nano-Fe3O4 particles within a specific particle size range into the system not only enhances TPU filling but also effectively inhibits the formation of silver streaks, improving the overall appearance quality. At the same time, nano-Fe3O4 particles have a good thermal response and an energy absorption efficiency faster than TPU itself. This can accelerate the energy absorption rate of self-repairing TPU materials, broaden the energy absorption range of TPU self-repair, and improve the self-repair efficiency and rate of the material. They are simple to operate and easy to use. Among them, nano-Fe3O4 particles with too high a particle size can easily result in a slow thermal response, low energy absorption rate, and poor material stability, while nano-Fe3O4 particles with too small a particle size can easily cause agglomeration, resulting in a decrease in the uniformity of the overall material performance.

[0017] Furthermore, the antioxidant is any one or more of hindered phenol antioxidants and phosphorus-containing antioxidants.

[0018] Furthermore, the hindered phenol antioxidant is any one or more of antioxidant 1010, antioxidant 1098 and antioxidant 3114; the phosphorus-containing antioxidant is any one or more of antioxidant 168, antioxidant PEP-36 and antioxidant 608.

[0019] Furthermore, the lubricant is one or more of esters, polyethylene waxes, stearic acids, and ethylene bisstearamides.

[0020] The present invention also provides a method for preparing the self-repairing polyurethane material, comprising the following steps:

[0021] The components are weighed and pre-mixed according to weight, and then added into a twin-screw extruder for full melt extrusion. After traction, cooling, pelletizing and drying, the self-repairing polyurethane material is obtained.

[0022] Furthermore, the temperature of the twin-screw extruder is set to 220-250° C., and the screw speed is 250-400 r / min.

[0023] The present invention also provides applications of the self-repairing polyurethane material in the fields of aerospace, electronic products, industry and transportation.

[0024] In summary, compared with the prior art, the present invention achieves the following technical effects:

[0025] (1) The self-repairing polyurethane material of the present invention is simple to prepare and has high self-repairing efficiency.

[0026] (2) The self-healing polyurethane material of the present invention maintains high self-healing ability while maintaining high mechanical properties and can effectively inhibit the generation of silver streaks. DETAILED DESCRIPTION

[0027] In order to help those skilled in the art better understand the solutions of the present invention, the technical solutions in the embodiments of the present invention are clearly and completely described below. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without making any creative efforts should fall within the scope of protection of the present invention.

[0028] Example

[0029] The present invention is further described below with reference to specific examples and comparative examples. The following specific examples are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the following examples, and are particularly not limited to the types of the various component raw materials used in the following specific examples.

[0030] 1. The sources of raw materials for the embodiments and comparative examples are as follows:

[0031] TPU resin A: thermoplastic polyester type, Shore A hardness of 72, HF-1075AP, Huafeng (Shore A hardness test standard is GB / T-2411-2008);

[0032] TPU resin B: thermoplastic polyester type, Shore A hardness of 84, HF-4385A-1, Huafeng;

[0033] TPU resin C: thermoplastic polyester type, Shore A hardness of 90, HF-1095A, Huafeng;

[0034] TPU resin D: polyether type, Shore A hardness of 82, HF-4080A-1, Huafeng;

[0035] 2-Amino-4-hydroxy-6-methylpyrimidinone: purity 99.79%, Shanghai Haohong Biopharmaceutical Technology Co., Ltd.

[0036] 1,6-Hexamethylene diisocyanate (HDI): purity 99.5%, Shandong Weishang Chemical Co., Ltd.

[0037] N-Methylpyrrolidone: AR analytical grade, Maoming Xiongda Chemical Co., Ltd. Zhongshan Branch;

[0038] Nano-Fe3O4 particles A: particle size D 50 20nm;

[0039] Nano-Fe3O4 particles B: particle size D 50 90nm;

[0040] Nano Fe3O4 particles C: particle size D 50 120nm;

[0041] Nano Fe3O4 particles D: particle size D 50 10nm;

[0042] Nano Fe3O4 particles E: particle size D 50 80nm;

[0043] Isopropyl ether: purity 99%, Tianjin Kailida Chemical;

[0044] Lubricant: Oxidized polyethylene wax, commercially available, the same substance was used in parallel experiments;

[0045] Antioxidant: Antioxidant 1010 and antioxidant 608 were mixed in a mass ratio of 1:1 and were commercially available. The same substances were used in parallel experiments.

[0046] The preparation methods of UPy-NCO in the examples and comparative examples of the present invention are as follows:

[0047] 500g of 2-amino-4-hydroxy-6-methylpyrimidone (UPy) was weighed and added to a reaction vessel, flushed with nitrogen, and reacted in a 50°C constant temperature oil bath for 1 hour. Subsequently, 472g of 1,6-hexamethylene diisocyanate (HDI) and 15.8g of N-methylpyrrolidone were weighed and mixed, then slowly added dropwise to the reaction vessel using a constant pressure dropping funnel. The temperature was raised to 100°C and stirred for 16 hours. After the reaction was completed, 250mL of chloroform was added to the reaction vessel, stirred evenly, and then slowly added dropwise to a beaker containing a mixed solvent of 2000mL and 500mL of isopropyl ether. The mixture was allowed to stand and filtered. The washing and filtration were repeated three times, and the mixture was dried in a 60°C oven for 10 hours to obtain a white UPy-NCO compound.

[0048] The preparation methods of nano Fe3O4 particles in the examples and comparative examples of the present invention are as follows:

[0049] (1) Nano-Fe3O4 particles A: particle size D 50 The thickness is 20 nm and the preparation method is as follows:

[0050] Weigh 0.8g FeCl3·6H2O and 4.6g sodium oleate (C 17 H 33 COONa) was dissolved in 30 mL of ethylene glycol and magnetically stirred at room temperature for 2 h to form a uniform orange-yellow solution; the mixture was added to a 50 mL polytetrafluoroethylene-lined reactor and sealed, and the reactor was placed in a constant temperature blast drying oven at 200°C for 24 h; after the reactor was naturally cooled to room temperature, the product was ultrasonically cleaned several times with anhydrous ethanol and then dried in a vacuum drying oven at 80°C to obtain black magnetic powder with a particle size of D 50 is 20nm.

[0051] (2) Nano-Fe3O4 particles B: particle size D50 The thickness is 90 nm and the preparation method is as follows:

[0052] Weigh 0.8g FeCl3·6H2O and 2.86g sodium oleate (C 17 H 33 COONa) was dissolved in 30 mL of ethylene glycol and magnetically stirred at room temperature for 2 h to form a uniform orange-yellow solution; the mixture was added to a 50 mL polytetrafluoroethylene-lined reactor and sealed, and the reactor was placed in a constant temperature blast drying oven at 200°C for 24 h; after the reactor was naturally cooled to room temperature, the product was ultrasonically cleaned several times with anhydrous ethanol and then dried in a vacuum drying oven at 80°C to obtain black magnetic powder with a particle size of D 50 It is 90nm.

[0053] (3) Nano-Fe3O4 particles C: particle size D 50 The thickness is 120 nm and the preparation method is as follows:

[0054] Weigh 0.8g FeCl3·6H2O and 2.58g sodium oleate (C 17 H 33 COONa) was dissolved in 30 mL of ethylene glycol and magnetically stirred at room temperature for 2 h to form a uniform orange-yellow solution; the mixture was added to a 50 mL polytetrafluoroethylene-lined reactor and sealed, and the reactor was placed in a constant temperature blast drying oven at 200°C for 24 h; after the reactor was naturally cooled to room temperature, the product was ultrasonically cleaned several times with anhydrous ethanol and then dried in a vacuum drying oven at 80°C to obtain black magnetic powder with a particle size of D 50 It is 120nm.

[0055] (4) Nano-Fe3O4 particles D: particle size D 50 The thickness is 10 nm and the preparation method is as follows:

[0056] Weigh 0.8g FeCl3·6H2O and 5.0g sodium oleate (C 17 H 33 COONa) was dissolved in 30 mL of ethylene glycol and magnetically stirred at room temperature for 2 h to form a uniform orange-yellow solution; the mixture was added to a 50 mL polytetrafluoroethylene-lined reactor and sealed, and the reactor was placed in a constant temperature blast drying oven at 200°C for 24 h; after the reactor was naturally cooled to room temperature, the product was ultrasonically cleaned several times with anhydrous ethanol and then dried in a vacuum drying oven at 80°C to obtain black magnetic powder with a particle size of D 50 It is 10nm.

[0057] (5) Nano-Fe3O4 particles D: particle size D 50 The thickness is 80 nm and the preparation method is as follows:

[0058] About 18.2 g of FeCl3·6H2O and about 7.3 g of FeCl2·4H2O were weighed and ultrasonically dispersed in 100 mL of deionized water. After they were completely dissolved, about 440 μL of hydrazine hydrate was added. After uniform dispersion, 47 mL of NH3·H2O was added and ultrasonically dispersed for about 10 minutes. The above mixture was poured into a reaction vessel and heated to 70°C in a water bath. After mechanical stirring and heat preservation for 1.5 hours under N2 atmosphere, the particles with a diameter of D were obtained after precipitation, washing and drying. 50 It is Fe3O4 nanoparticles of about 80nm.

[0059] The preparation method of the self-repairing polyurethane in the embodiments of the present invention and the comparative examples comprises the following steps:

[0060] After premixing TPU resin, UPy-NCO compound, nano-Fe₃O₄ particles, lubricant, and antioxidant according to weight ratio, the mixture was fed into a twin-screw extruder for full melt extrusion. The resulting self-healing polyurethane material was then obtained after towing, cooling, pelletizing, and drying. The twin-screw extruder temperature was set at 220-250°C, and the screw speed was 250-400 rpm.

[0061] 2. Various performance test methods

[0062] (1) Self-healing performance and initial tensile strength test:

[0063] The test standard is GBT528-2009. A corresponding dumbbell-shaped spline with a size of 25mm (length) × 4mm (width) × 2mm (thickness) is cut out with a cutter. The sample is cut into two halves in the middle, and the fracture surfaces are manually brought into contact for 10s. Then, it is heated at 120°C for 20min, and then treated at a low temperature of 60°C for 6h, 12h and 24h respectively. No external force is applied in the middle, and self-repairing samples after different treatment times are obtained. The tensile strength test is carried out at 200mm / min.

[0064] The self-repair efficiency is calculated as follows: Repair efficiency (%) = (tensile strength after repair / tensile strength before repair) * 100%.

[0065] (2) Hydrolysis resistance (silver streaks): Use Haitian injection molding machine, select water splash verification sample mold, injection temperature is 250℃, and after 10 minutes of heat retention, inject another sample, perform statistical analysis on the appearance of the sample, calculate the area of ​​silver streaks on the sample, and present it as a percentage.

[0066] The distribution ratios and test results of each group are shown in Table 1 and Table 2:

[0067] Table 1 Example of each group distribution ratio (weight parts) and effect

[0068] Table 2 Comparative Examples 1 to 4: Distribution ratio (parts by weight) and effects

[0069] Compared with Example 1, Comparative Example 1 does not add UPy-NCO. Compared with Example 5, Comparative Example 2 adds too much UPy-NCO. When the UPy-NCO content exceeds the specified value, its initial tensile strength is lower than that of Example 5, and its self-repair efficiency and self-repair rate are significantly lower than those of the Example. Compared with Example 1, Comparative Example 3 does not add nano-Fe3O4 particles, but only adds UPy-NCO or nano-Fe3O4 particles. The initial tensile strength of the modified TPU is lower than that of the Example, and its self-repair efficiency and self-repair rate are significantly lower than those of the Example. Compared with Example 5, Comparative Example 4 adds too much nano-Fe3O4 particles. When the content of nano-Fe3O4 particles exceeds the specified value, its self-repair efficiency and self-repair rate are significantly lower than those of the Example. None of the above comparative examples can achieve a high self-repair rate, high initial tensile strength, and suppress the formation of silver streaks.

[0070] Based on the test data on self-repair efficiency, initial tensile strength and silver streak ratio in Tables 1 and 2, the polyurethane material prepared by the ratio of the embodiment has an initial tensile property greater than 30 MPa, a silver streak ratio ≤16%, and a self-repair effect of not less than 80% after 24 hours, provided that the initial tensile strength meets the conditions. This has obvious advantages over the comparative example and is superior to existing self-repairing polyurethane materials.

[0071] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A self-repairing polyurethane material, characterized in that: In parts by weight, it includes the following components:

2. The self-repairing polyurethane material according to claim 1, characterized in that: The TPU resin is thermoplastic polyester TPU.

3. The self-repairing polyurethane material according to claim 1, characterized in that: The Shore A hardness of the TPU resin is 70-90.

4. The self-repairing polyurethane material according to claim 1, characterized in that: The structural formula of the UPy-NCO is shown in the figure below:

5. The self-repairing polyurethane material according to claim 1, characterized in that: The particle size D of the nano Fe3O4 particles 50 It is 10~120nm.

6. The self-repairing polyurethane material according to claim 1, characterized in that: The antioxidant is any one or more of a hindered phenol antioxidant and a phosphorus-containing antioxidant.

7. The self-repairing polyurethane material according to claim 1, characterized in that: The lubricant is one or more of esters, polyethylene waxes, stearic acids, and ethylene bis stearamides.

8. The method for preparing the self-repairing polyurethane material according to any one of claims 1 to 7, characterized in that: The steps include: After weighing each component by weight and premixing, the components are added into a twin-screw extruder for full melt extrusion, and the self-repairing polyurethane material is obtained after traction, cooling, pelletizing and drying.

9. Application of the self-healing polyurethane material according to any one of claims 1 to 7 in the fields of aerospace, electronic products, industry and transportation.

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