High performance room temperature self-healing polyurethane elastomer and method of making same

Abstract

The application relates to a high-performance room-temperature self-repairing polyurethane elastomer and a preparation method thereof. The polyurethane elastomer is synthesized from a diisocyanate containing an asymmetric aliphatic ring, a polyether diol or a polyester diol and a dynamic hydrogen bond chain extender. Linear and nonlinear hydrogen bonds exist in the polyurethane molecular chain. The linear hydrogen bonds endow the material with good mechanical properties, and the nonlinear hydrogen bonds enable the polyurethane elastomer to realize self-repairing at room temperature while maintaining the strength. The high steric hindrance of the asymmetric aliphatic ring structure can inhibit the crystallization of the polyurethane segment, and the transparency of the polyurethane is improved. Compared with the prior art, the polyurethane elastomer prepared by the application has excellent tensile properties, the tensile strength is greater than 30 MPa, the breaking strain is greater than 1000%, the polyurethane elastomer also has good self-repairing performance, the room-temperature repairing efficiency is greater than 80% under the assistance of trace water after 48h of repairing, and the polyurethane elastomer also has good transparency.

Description

Technical Field

[0001] This invention relates to the field of self-healing elastomer materials technology, and in particular to a high-performance room temperature self-healing polyurethane elastomer and its preparation method. Background Technology

[0002] Polyurethane (PU) is a class of polymers containing a large amount of urethane in its molecular structure. Also known as polyurethane, its full English name is polyurethane. Due to its excellent elasticity and processability, polyurethane materials are widely used in construction, automotive, electronics, packaging, and footwear industries. However, polyurethane materials inevitably suffer physical damage during use. To extend their service life, various reversible dynamic bonds, such as hydrogen bonds, disulfide bonds, imine groups, and metal coordination bonds, are introduced into polyurethane elastomers to endow them with self-healing properties.

[0003] However, the contradiction between mechanical properties and self-healing properties is a major challenge in the research of self-healing polyurethane elastomers. Introducing compounds containing a large number of hydrogen bond acceptors and donors into polyurethane elastomers is an effective strategy to improve the strength of the material. However, if a large number of ordinary linear hydrogen bonds are introduced, it will induce elastomer crystallization, reduce the activity of molecular chain movement, and worsen the repair performance of the elastomer.

[0004] Chinese patent CN109705300A discloses a self-healing polyurethane and its preparation method, which utilizes the synergistic effect of multiple dynamic bonds. First, it includes the dynamic hydrogen bond system inherent in the polyurethane system. Second, the oxime urethane bond generated by the reaction of the oxime group with the isocyanate group is also a kind of dynamic covalent bond. Finally, it can also form a dynamic metal-coordinate bond by introducing metal ions to coordinate with the oxime. However, this polyurethane material has the technical problem of poor mechanical properties.

[0005] Chinese patent CN118620171A discloses a high-performance self-healing polyurethane and its preparation method. By introducing multiple linear hydrogen bonds into the polyurethane molecular chain, a polyurethane with a strength range of 20-40 MPa is obtained. However, it needs to be heated at 50-85℃ for 12-24 hours to restore the mechanical strength to more than 90%.

[0006] Currently, the few reported self-healing polyurethane materials at room temperature are those that compromise mechanical properties, and are accompanied by high preparation costs and complex synthesis processes. Therefore, it is necessary to design a polyurethane elastomer with self-healing function and excellent mechanical properties at room temperature, as well as its preparation method, to solve the above problems. Summary of the Invention

[0007] The purpose of this invention is to overcome the defects of the prior art by providing a high-performance room-temperature self-healing polyurethane elastomer and its preparation method. The prepared polyurethane elastomer has high transparency, self-healing function at room temperature, and excellent mechanical properties.

[0008] The conceptual process of this application is as follows: This invention synthesizes asymmetric aliphatic ring diisocyanate-terminated polyether or polyester, and then uses a chain extender containing dynamic hydrogen bonds to prepare a self-healing polyurethane elastomer at room temperature through a chain extension reaction, while ensuring the good mechanical properties and room temperature self-healing properties of the polyurethane elastomer.

[0009] The objective of this invention can be achieved through the following technical solutions:

[0010] On one hand, the present invention provides a high-performance room temperature self-healing polyurethane elastomer, wherein the raw materials comprise the following components by molar proportions:

[0011] Diol: 10 parts;

[0012] Diisocyanate: 20-26 parts;

[0013] Catalyst: 0.0002–0.001 parts

[0014] Dynamic hydrogen bond chain extender: 10-16 parts;

[0015] Solvent: 700-1200 parts.

[0016] Furthermore, the diol is a polyether diol or a polyester diol. The polyether diol includes at least one of polytrimethylene ether diol (PO3G) and polytetramethylene ether diol (PTMG), and the polyester diol includes at least one of polycarbonate diol (PCDL) and polycaprolactone diol (PCL). The number average molecular weight of the diol is 1000 to 5000 g / mol.

[0017] Preferably, the polyether diol is polytetramethylene ether diol (PTMG), and the polyester diol is polycaprolactone diol (PCL).

[0018] Furthermore, the diisocyanate is at least one of dicyclohexylmethane diisocyanate (HMDI) and isophorone diisocyanate (IPDI).

[0019] Furthermore, the catalyst is at least one of stannous octoate, tetramethylbutanediamine, and dibutyltin dilaurate.

[0020] Preferably, the catalyst is at least one of stannous octoate and dibutyltin dilaurate.

[0021] Furthermore, the dynamic hydrogen bond chain extender is at least one of methylenebis(1-aminothiourea), thiourea, dimethylthiourea, and thiomethylhydrazine.

[0022] Furthermore, the solvent is at least one selected from toluene, N,N-dimethylformamide (DMF), acetone, butanone, N,N-dimethylacetamide (DMAC), tetrahydrofuran, and dimethyl sulfoxide.

[0023] Preferably, the solvent is at least one of N,N-dimethylformamide (DMF) and acetone.

[0024] On the other hand, the present invention also provides a method for preparing a high-performance room temperature self-healing polyurethane elastomer, comprising the following steps:

[0025] S1. Before the reaction, 10 parts of diol are dehydrated under vacuum at 110°C for 2-3 hours. Then, the reaction system is cooled to 60-90°C, 20-26 parts of diisocyanate are added, and the reaction is carried out for 1-3 hours under the action of 0.0002-0.001 parts of catalyst to obtain the prepolymer.

[0026] S2. Adjust the temperature of the reaction system to 25-70℃, add 200-300 parts of solvent to dilute the prepolymer obtained in S1, then dissolve 10-16 parts of dynamic hydrogen bond chain extender in 500-900 parts of solvent and add it dropwise to the prepolymer solution, and carry out the chain extension reaction for 2-12 hours to obtain polyurethane.

[0027] S3. The polyurethane obtained in S2 is soaked in deionized water for 12 hours, and then vacuum dried at 80°C for 48 hours to obtain a room temperature self-healing polyurethane elastomer.

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] (1) The preparation method of high-performance room temperature self-healing polyurethane elastomer provided by the present invention introduces a chain extender containing both linear and nonlinear hydrogen bonds into the self-healing polyurethane system, thereby overcoming the defect that excessive linear hydrogen bond content causes molecular chain aggregation and crystallization, thus affecting the self-healing performance of polyurethane.

[0030] (2) The self-healing polyurethane elastomer provided by the present invention has good mechanical properties and exhibits strain hardening during tension. It not only has high strength (greater than 30MPa) but also good transparency. At the same time, it has good room temperature self-healing properties. The repair process does not require additional repair agents or energy input. With the assistance of water, the scratches can disappear after being placed at room temperature for 4 hours.

[0031] (3) The method of the present invention has mild reaction conditions, simple preparation process, cheap raw materials, and high added value of the obtained products. It has high application value in the fields of coating, optical equipment, flexible electronic equipment and has strong industrial competitiveness. Attached Figure Description

[0032] Figure 1 The images show the self-healing of IP-PTMG-TBD prepared in Example 4 of this invention under a polarizing microscope: (a) after cutting, at room temperature for 0 hours; (b) after cutting, at room temperature for 4 hours after water treatment. Detailed Implementation

[0033] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. Any preparation methods, materials, structures, or compositional ratios not explicitly described in this technical solution are considered common technical features disclosed in the prior art.

[0034] The raw materials used in the following embodiments are as follows, but are not limited to the raw materials described below. The following raw materials are used as specific embodiments to illustrate the effect of the heat-resistant transparent self-healing thermoplastic polyurethane elastomer containing dynamic hydrogen bonds.

[0035] The tensile strength and elongation at break test methods refer to GB / T 528-2009. The dumbbell-shaped polyurethane specimen size is 75×4×2mm, the tensile rate is 50mm / min, and the toughness is the integral area of ​​the stress-strain curve.

[0036] Repair efficiency: The dumbbell-shaped specimen was cut in half with a blade, a small amount of water was applied to the broken surface, and the broken surfaces were then spliced ​​together. After repairing at room temperature for 48 hours, a tensile test was performed. Each group of experiments had at least three parallel samples. Self-healing efficiency = tensile strength (fracture strain) of the repaired sample / tensile strength (fracture strain) of the original sample.

[0037] Transmittance: Measured using a spectrophotometer method according to GB / T 2410-2008, with a sample thickness of 1 mm.

[0038] Example 1

[0039] This invention provides a method for preparing a high-performance room-temperature self-healing polyurethane elastomer, comprising the following steps:

[0040] S1. Polytetramethylene ether diol (PTMG) (Mn = 2000) (20g, 10mmol) was dehydrated under vacuum at 110℃ for 2h before the reaction. The reaction system was then cooled to 70℃, and isophorone diisocyanate (IPDI) (5g, 22mmol) and 0.4mg stannous octoate were added. The reaction was carried out at 70℃ for 2h to obtain a prepolymer with a certain viscosity.

[0041] S2. Adjust the temperature of the reaction system to 60℃, add 20mL of DMF to the prepolymer obtained in S1 to dilute the viscosity, then dissolve methylene bis(1-aminothiourea) (BTO) (2.3g, 12mmol) in 60mL of DMF and add it dropwise to the diluted prepolymer solution, and carry out the chain extension reaction for 3h to obtain polyurethane.

[0042] S3. The polyurethane obtained in S2 was soaked in deionized water for 12 hours and then vacuum dried at 80°C for 48 hours to obtain a room temperature self-healing polyurethane elastomer, denoted as IP-PTMG-BTO. The dried product was then pulverized and hot-pressed at 130°C for 4 minutes in a flat vulcanizing machine to obtain a dumbbell-shaped polyurethane sample of IP-PTMG-BTO.

[0043] The tensile properties of IP-PTMG-BTO dumbbell-shaped polyurethane specimens were measured according to GB / T 528-2009. The specimens were then cut in half, and a small amount of water was applied to the cut surface. The specimens were allowed to heal at room temperature for 48 hours before being subjected to tensile testing. The test results are shown in Table 1.

[0044] According to GB / T 2410-2008, the transmittance of a 1 mm thick sample was measured. The test results are shown in Table 1. The transmittance (wavelength 600 nm) of the IP-PTMG-BTO polyurethane elastomer prepared in this embodiment is 95.2%.

[0045] Example 2

[0046] This invention provides a method for preparing a high-performance room-temperature self-healing polyurethane elastomer, comprising the following steps:

[0047] S1. Polytetramethylene ether diol (PTMG) (Mn = 2000) (20g, 10mmol) was dehydrated under vacuum at 110℃ for 2h before the reaction. The reaction system was then cooled to 70℃, and isophorone diisocyanate (IPDI) (5g, 22mmol) and 0.4mg stannous octoate were added. The reaction was carried out at 70℃ for 2h to obtain a prepolymer with a certain viscosity.

[0048] S2. Adjust the temperature of the reaction system to 40℃, add 20mL of acetone to the prepolymer obtained in S1 to dilute the viscosity, then dissolve thiourea (THA) (0.9g, 12mmol) in 40mL of acetone and add it dropwise to the diluted prepolymer solution, and carry out the chain extension reaction for 2h to obtain polyurethane.

[0049] S3. The polyurethane obtained in S2 was soaked in deionized water for 12 hours and then vacuum dried at 80°C for 48 hours to obtain a room temperature self-healing polyurethane elastomer, denoted as IP-PTMG-THA. The dried product was then pulverized and hot-pressed at 130°C for 4 minutes in a flat vulcanizing machine to obtain a dumbbell-shaped polyurethane sample of IP-PTMG-THA.

[0050] The tensile properties of the IP-PTMG-THA dumbbell-shaped polyurethane specimens were measured according to GB / T 528-2009. The specimens were then cut in half, and a small amount of water was applied to the cut surface. The specimens were allowed to heal at room temperature for 48 hours before being subjected to tensile testing. The test results are shown in Table 1.

[0051] According to GB / T 2410-2008, the transmittance of a 1 mm thick sample was measured. The test results are shown in Table 1. The transmittance (wavelength 600 nm) of the IP-PTMG-THA polyurethane elastomer prepared in this embodiment is 93.8%.

[0052] Example 3

[0053] This invention provides a method for preparing a high-performance room-temperature self-healing polyurethane elastomer, comprising the following steps:

[0054] S1. Polytetramethylene ether diol (PTMG) (Mn = 2000) (20g, 10mmol) was dehydrated under vacuum at 110℃ for 2h before the reaction. The reaction system was then cooled to 70℃, and isophorone diisocyanate (IPDI) (5g, 22mmol) and 0.4mg stannous octoate were added. The reaction was carried out at 70℃ for 2h to obtain a prepolymer with a certain viscosity.

[0055] S2. At 70°C, 20 mL of DMF was added to the prepolymer obtained in S1 to dilute the viscosity. Then, dimethyl thiourea (DTA) (1.6 g, 12 mmol) was dissolved in 40 mL of DMF and added dropwise to the diluted prepolymer solution. The chain extension reaction was carried out for 12 h to obtain polyurethane.

[0056] S3. The polyurethane obtained in S2 was soaked in deionized water for 12 hours and then vacuum dried at 80°C for 48 hours to obtain a room temperature self-healing polyurethane elastomer, denoted as IP-PTMG-DTA. The dried product was then pulverized and hot-pressed at 130°C for 4 minutes in a flat vulcanizing machine to obtain a dumbbell-shaped polyurethane sample of IP-PTMG-DTA.

[0057] The tensile properties of IP-PTMG-DTA dumbbell-shaped polyurethane specimens were measured according to GB / T 528-2009. The specimens were then cut in half, and a small amount of water was applied to the cut surface. The specimens were allowed to heal at room temperature for 48 hours before being subjected to tensile testing. The test results are shown in Table 1.

[0058] According to GB / T 2410-2008, the transmittance of a 1 mm thick sample was measured. The test results are shown in Table 1. The transmittance (wavelength 600 nm) of the IP-PTMG-DTA polyurethane elastomer prepared in this embodiment is 90.4%.

[0059] Example 4

[0060] This invention provides a method for preparing a high-performance room-temperature self-healing polyurethane elastomer, comprising the following steps:

[0061] S1. Polytetramethylene ether diol (PTMG) (Mn = 2000) (20g, 10mmol) was dehydrated under vacuum at 110℃ for 2h before the reaction. The reaction system was then cooled to 70℃, and isophorone diisocyanate (IPDI) (5g, 22mmol) and 0.4mg stannous octoate were added. The reaction was carried out at 70℃ for 2h to obtain a prepolymer with a certain viscosity.

[0062] S2. Adjust the temperature of the reaction system to 40℃, add 20mL of acetone to the prepolymer obtained in S1 to dilute the viscosity, then dissolve 1.3g of methyl thiocyanate (TBD) in 60mL of acetone and add it dropwise to the diluted prepolymer solution, and carry out the chain extension reaction for 3h to obtain polyurethane.

[0063] S3. The polyurethane obtained in S2 was soaked in deionized water for 12 hours and then vacuum dried at 80°C for 48 hours to obtain a room temperature self-healing polyurethane elastomer, denoted as IP-PTMG-TBD. The dried product was then pulverized and hot-pressed at 130°C for 4 minutes in a flat vulcanizing machine to obtain a dumbbell-shaped polyurethane sample of IP-PTMG-TBD.

[0064] The tensile properties of the IP-PTMG-TBD dumbbell-shaped polyurethane specimens were measured according to GB / T 528-2009. The specimens were then cut in half, and a small amount of water was applied to the cut surface. The specimens were allowed to heal at room temperature for 48 hours before being subjected to tensile testing. The test results are shown in Table 1.

[0065] like Figure 1 The image shown is a self-healing photograph of the IP-PTMG-TBD prepared in this embodiment under a polarizing microscope. Figure 1 (a) shows the state of the polyurethane elastomer after it has been cut and left at room temperature for 0 hours. Figure 1 (b) The scratches disappeared after the polyurethane elastomer was cut and placed at room temperature for 4 hours with the aid of water, indicating that the IP-PTMG-TBD prepared in this embodiment has good room temperature self-healing properties.

[0066] According to GB / T 2410-2008, the transmittance of a 1 mm thick sample was measured. The test results are shown in Table 1. The transmittance (wavelength 600 nm) of the IP-PTMG-TBD polyurethane elastomer prepared in this embodiment is 90.2%.

[0067] Example 5

[0068] This invention provides a method for preparing a high-performance room-temperature self-healing polyurethane elastomer, comprising the following steps:

[0069] S1. Polytetramethylene ether diol (PTMG) (Mn = 2000) (20g, 10mmol) was dehydrated under vacuum at 110℃ for 2h before the reaction. The reaction system was then cooled to 70℃, and dicyclohexylmethane diisocyanate (HMDI) (5.8g, 22mmol) and 0.6mg dibutyltin dilaurate were added. The reaction was carried out at 70℃ for 2h to obtain a prepolymer with a certain viscosity.

[0070] S2. Adjust the temperature of the reaction system to 60℃, add 20mL of DMF to the prepolymer obtained in S1 to dilute the viscosity, then dissolve methylene bis(1-aminothiourea) (BTO) (2.3g, 12mmol) in 60mL of DMF and add it dropwise to the diluted prepolymer solution, and carry out the chain extension reaction for 3h to obtain polyurethane.

[0071] S3. The polyurethane obtained in S2 was soaked in deionized water for 12 hours and then vacuum dried at 80°C for 48 hours to obtain a room temperature self-healing polyurethane elastomer, denoted as HM-PTMG-BTO. The dried product was then pulverized and hot-pressed at 130°C for 4 minutes in a flat vulcanizing machine to obtain a dumbbell-shaped polyurethane sample of HM-PTMG-BTO.

[0072] The tensile properties of HM-PTMG-BTO dumbbell-shaped polyurethane specimens were measured according to GB / T 528-2009. The specimens were then cut in half, and a small amount of water was applied to the cut surface. The specimens were allowed to heal at room temperature for 48 hours before being subjected to tensile testing. The test results are shown in Table 1.

[0073] According to GB / T 2410-2008, the transmittance of a 1 mm thick sample was measured. The test results are shown in Table 1. The transmittance (wavelength 600 nm) of the HM-PTMG-BTO polyurethane elastomer prepared in this embodiment is 91.9%.

[0074] Example 6

[0075] This invention provides a method for preparing a high-performance room-temperature self-healing polyurethane elastomer, comprising the following steps:

[0076] S1. Polytetramethylene ether diol (PTMG) (Mn = 2000) (20g, 10mmol) was dehydrated under vacuum at 110℃ for 2h before the reaction. The reaction system was then cooled to 70℃, and dicyclohexylmethane diisocyanate (HMDI) (5.8g, 22mmol) and 0.6mg dibutyltin dilaurate were added. The reaction was carried out at 70℃ for 2h to obtain a prepolymer with a certain viscosity.

[0077] S2. Adjust the temperature of the reaction system to 40℃, add 20mL of acetone to the prepolymer obtained in S1 to dilute the viscosity, then dissolve thiourea (THA) (0.9g, 12mmol) in 40mL of acetone and add it dropwise to the diluted prepolymer solution, and carry out the chain extension reaction for 2h to obtain polyurethane.

[0078] S3. The polyurethane obtained in S2 was soaked in deionized water for 12 hours and then vacuum dried at 80°C for 48 hours to obtain a room temperature self-healing polyurethane elastomer, denoted as HM-PTMG-THA. The dried product was then pulverized and hot-pressed at 130°C for 4 minutes in a flat vulcanizing machine to obtain a dumbbell-shaped polyurethane sample of HM-PTMG-THA.

[0079] The tensile properties of HM-PTMG-THA dumbbell-shaped polyurethane specimens were measured according to GB / T 528-2009. The specimens were then cut in half, and a small amount of water was applied to the cut surface. The specimens were allowed to heal at room temperature for 48 hours before being subjected to tensile testing. The test results are shown in Table 1.

[0080] According to GB / T 2410-2008, the transmittance of a 1 mm thick sample was measured. The test results are shown in Table 1. The transmittance (wavelength 600 nm) of the HM-PTMG-THA polyurethane elastomer prepared in this embodiment is 91.3%.

[0081] Example 7

[0082] This invention provides a method for preparing a high-performance room-temperature self-healing polyurethane elastomer, comprising the following steps:

[0083] S1. Polytetramethylene ether diol (PTMG) (Mn = 2000) (20g, 10mmol) was dehydrated under vacuum at 110℃ for 2h before the reaction. The reaction system was then cooled to 70℃, and dicyclohexylmethane diisocyanate (HMDI) (5.8g, 22mmol) and 0.6mg dibutyltin dilaurate were added. The reaction was carried out at 70℃ for 2h to obtain a prepolymer with a certain viscosity.

[0084] S2. At 70°C, 20 mL of DMF was added to the prepolymer obtained in S1 to dilute the viscosity. Then, dimethyl thiourea (DTA) (1.6 g, 12 mmol) was dissolved in 40 mL of DMF and added dropwise to the diluted prepolymer solution. The chain extension reaction was carried out for 12 h to obtain polyurethane.

[0085] S3. The polyurethane obtained in S2 was soaked in deionized water for 12 hours and then vacuum dried at 80°C for 48 hours to obtain a room temperature self-healing polyurethane elastomer, denoted as HM-PTMG-DTA. The dried product was then pulverized and hot-pressed at 130°C for 4 minutes in a flat vulcanizing machine to obtain a dumbbell-shaped polyurethane sample of HM-PTMG-DTA.

[0086] The tensile properties of HM-PTMG-DTA dumbbell-shaped polyurethane specimens were measured according to GB / T 528-2009. The specimens were then cut in half, and a small amount of water was applied to the cut surface. The specimens were allowed to heal at room temperature for 48 hours before being subjected to tensile testing. The test results are shown in Table 1.

[0087] According to GB / T 2410-2008, the transmittance of a 1 mm thick sample was measured. The test results are shown in Table 1. The transmittance (wavelength 600 nm) of the HM-PTMG-DTA polyurethane elastomer prepared in this embodiment is 92.2%.

[0088] Example 8

[0089] This invention provides a method for preparing a high-performance room-temperature self-healing polyurethane elastomer, comprising the following steps:

[0090] S1. Polytetramethylene ether diol (PTMG) (Mn = 2000) (20g, 10mmol) was dehydrated under vacuum at 110℃ for 2h before the reaction. The reaction system was then cooled to 70℃, and dicyclohexylmethane diisocyanate (HMDI) (5.8g, 22mmol) and 0.6mg dibutyltin dilaurate were added. The reaction was carried out at 70℃ for 2h to obtain a prepolymer with a certain viscosity.

[0091] S2. Adjust the temperature of the reaction system to 40℃, add 20mL of acetone to the prepolymer obtained in S1 to dilute the viscosity, then dissolve 1.3g of methyl thiocyanate (TBD) in 60mL of acetone and add it dropwise to the diluted prepolymer solution, and carry out the chain extension reaction for 3h to obtain polyurethane.

[0092] S3. The polyurethane obtained in S2 was soaked in deionized water for 12 hours and then vacuum dried at 80°C for 48 hours to obtain a room temperature self-healing polyurethane elastomer, denoted as HM-PTMG-TBD. The dried product was then pulverized and hot-pressed at 130°C for 4 minutes in a flat vulcanizing machine to obtain a dumbbell-shaped polyurethane sample of HM-PTMG-TBD.

[0093] The tensile properties of HM-PTMG-TBD dumbbell-shaped polyurethane specimens were measured according to GB / T 528-2009. The specimens were then cut in half, and a small amount of water was applied to the cut surface. The specimens were allowed to heal at room temperature for 48 hours before being subjected to tensile testing. The test results are shown in Table 1.

[0094] According to GB / T 2410-2008, the transmittance of a 1 mm thick sample was measured. The test results are shown in Table 1. The transmittance (wavelength 600 nm) of the HM-PTMG-TBD polyurethane elastomer prepared in this embodiment is 92.8%.

[0095] Example 9

[0096] This invention provides a method for preparing a high-performance room-temperature self-healing polyurethane elastomer, comprising the following steps:

[0097] S1. Polycaprolactone diol (PCL) (Mn = 2000) (20g, 10mmol) was dehydrated under vacuum at 110℃ for 2h before the reaction. The reaction system was then cooled to 70℃, and isophorone diisocyanate (IPDI) (5g, 22mmol) and 0.4mg stannous octoate were added. The reaction was carried out at 70℃ for 2h to obtain a prepolymer with a certain viscosity.

[0098] S2. Adjust the temperature of the reaction system to 60℃, add 20mL of DMF to the prepolymer obtained in S1 to dilute the viscosity, then dissolve methylene bis(1-aminothiourea) (BTO) (2.3g, 12mmol) in 60mL of DMF and add it dropwise to the diluted prepolymer solution, and carry out the chain extension reaction for 3h to obtain polyurethane.

[0099] S3. The polyurethane obtained in S2 was soaked in deionized water for 12 hours and then vacuum dried at 80°C for 48 hours to obtain a room temperature self-healing polyurethane elastomer, denoted as IP-PCL-BTO. The dried product was then pulverized and hot-pressed at 130°C for 4 minutes in a flat vulcanizing machine to obtain a dumbbell-shaped polyurethane sample of IP-PCL-BTO.

[0100] The tensile properties of IP-PCL-BTO dumbbell-shaped polyurethane specimens were measured according to GB / T 528-2009. The specimens were then cut in half, and a small amount of water was applied to the cut surface. The specimens were allowed to heal at room temperature for 48 hours before being subjected to tensile testing. The test results are shown in Table 1.

[0101] According to GB / T 2410-2008, the transmittance of a 1 mm thick sample was measured. The test results are shown in Table 1. The transmittance (wavelength 600 nm) of the IP-PCL-BTO polyurethane elastomer prepared in this embodiment is 93.9%.

[0102] Example 10

[0103] This invention provides a method for preparing a high-performance room-temperature self-healing polyurethane elastomer, comprising the following steps:

[0104] S1. Polycaprolactone diol (PCL) (Mn = 2000) (20g, 10mmol) was dehydrated under vacuum at 110℃ for 2h before the reaction. The reaction system was then cooled to 70℃, and isophorone diisocyanate (IPDI) (5g, 22mmol) and 0.4mg stannous octoate were added. The reaction was carried out at 70℃ for 2h to obtain a prepolymer with a certain viscosity.

[0105] S2. Adjust the temperature of the reaction system to 40℃, add 20mL of acetone to the prepolymer obtained in S1 to dilute the viscosity, then dissolve thiourea (THA) (0.9g, 12mmol) in 40mL of acetone and add it dropwise to the diluted prepolymer solution, and carry out the chain extension reaction for 2h to obtain polyurethane.

[0106] S3. The polyurethane obtained in S2 was soaked in deionized water for 12 hours and then vacuum dried at 80°C for 48 hours to obtain a room temperature self-healing polyurethane elastomer, denoted as IP-PCL-THA. The dried product was then pulverized and hot-pressed at 130°C for 4 minutes in a flat vulcanizing machine to obtain a dumbbell-shaped polyurethane sample of IP-PCL-THA.

[0107] The tensile properties of the IP-PCL-THA dumbbell-shaped polyurethane specimens were measured according to GB / T 528-2009. The specimens were then cut in half, and a small amount of water was applied to the cut surface. The specimens were allowed to heal at room temperature for 48 hours before being subjected to tensile testing. The test results are shown in Table 1.

[0108] According to GB / T 2410-2008, the transmittance of a 1 mm thick sample was measured. The test results are shown in Table 1. The transmittance (wavelength 600 nm) of the IP-PCL-THA polyurethane elastomer prepared in this embodiment is 90.1%.

[0109] Example 11

[0110] This invention provides a method for preparing a high-performance room-temperature self-healing polyurethane elastomer, comprising the following steps:

[0111] S1. Polycaprolactone diol (PCL) (Mn = 2000) (20g, 10mmol) was dehydrated under vacuum at 110℃ for 2h before the reaction. The reaction system was then cooled to 70℃, and isophorone diisocyanate (IPDI) (5g, 22mmol) and 0.4mg stannous octoate were added. The reaction was carried out at 70℃ for 2h to obtain a prepolymer with a certain viscosity.

[0112] S2. At 70°C, 20 mL of DMF was added to the prepolymer obtained in S1 to dilute the viscosity. Then, dimethyl thiourea (DTA) (1.6 g, 12 mmol) was dissolved in 40 mL of DMF and added dropwise to the diluted prepolymer solution. The chain extension reaction was carried out for 12 h to obtain polyurethane.

[0113] S3. The polyurethane obtained in S2 was soaked in deionized water for 12 hours and then vacuum dried at 80°C for 48 hours to obtain a room temperature self-healing polyurethane elastomer, denoted as IP-PCL-DTA. The dried product was then pulverized and hot-pressed at 130°C for 4 minutes in a flat vulcanizing machine to obtain a dumbbell-shaped polyurethane sample of IP-PCL-DTA.

[0114] The tensile properties of IP-PCL-DTA dumbbell-shaped polyurethane specimens were measured according to GB / T 528-2009. The specimens were then cut in half, and a small amount of water was applied to the cut surface. The specimens were allowed to heal at room temperature for 48 hours before being subjected to tensile testing. The test results are shown in Table 1.

[0115] According to GB / T 2410-2008, the transmittance of a 1 mm thick sample was measured. The test results are shown in Table 1. The transmittance (wavelength 600 nm) of the IP-PCL-DTA polyurethane elastomer prepared in this embodiment is 92.5%.

[0116] Example 12

[0117] This invention provides a method for preparing a high-performance room-temperature self-healing polyurethane elastomer, comprising the following steps:

[0118] S1. Polycaprolactone diol (PCL) (Mn = 2000) (20g, 10mmol) was dehydrated under vacuum at 110℃ for 2h before the reaction. The reaction system was then cooled to 70℃, and isophorone diisocyanate (IPDI) (5g, 22mmol) and 0.4mg stannous octoate were added. The reaction was carried out at 70℃ for 2h to obtain a prepolymer with a certain viscosity.

[0119] S2. Adjust the temperature of the reaction system to 40℃, add 20mL of acetone to the prepolymer obtained in S1 to dilute the viscosity, then dissolve 1.3g of methyl thiocyanate (TBD) in 60mL of acetone and add it dropwise to the diluted prepolymer solution, and carry out the chain extension reaction for 3h to obtain polyurethane.

[0120] S3. The polyurethane obtained in S2 was soaked in deionized water for 12 hours and then vacuum dried at 80°C for 48 hours to obtain a room temperature self-healing polyurethane elastomer, denoted as IP-PCL-TBD. The dried product was then pulverized and hot-pressed at 130°C for 4 minutes in a flat vulcanizing machine to obtain a dumbbell-shaped polyurethane sample of IP-PCL-TBD.

[0121] The tensile properties of the IP-PCL-TBD dumbbell-shaped polyurethane specimens were measured according to GB / T 528-2009. The specimens were then cut in half, and a small amount of water was applied to the cut surface. The specimens were allowed to heal at room temperature for 48 hours before being subjected to tensile testing. The test results are shown in Table 1.

[0122] According to GB / T 2410-2008, the transmittance of a 1 mm thick sample was measured. The test results are shown in Table 1. The transmittance (wavelength 600 nm) of the IP-PCL-TBD polyurethane elastomer prepared in this embodiment is 91.7%.

[0123] Comparative Example 1

[0124] This invention provides a method for preparing a high-performance room-temperature self-healing polyurethane elastomer, comprising the following steps:

[0125] S1. Polytetramethylene ether diol (PTMG) (Mn = 2000) (20g, 10mmol) was dehydrated under vacuum at 110℃ for 2h before the reaction. The reaction system was then cooled to 70℃, and isophorone diisocyanate (IPDI) (5g, 22mmol) and 0.4mg stannous octoate were added. The reaction was carried out at 70℃ for 2h to obtain a prepolymer with a certain viscosity.

[0126] S2. Adjust the temperature of the reaction system to 60℃, add 20mL of DMF to the prepolymer obtained in S1 to dilute the viscosity, then dissolve adipic dihydrazide (ADH) (2.1g, 12mmol) in 80mL of DMF and add it dropwise to the diluted prepolymer solution, and carry out the chain extension reaction for 3h to obtain polyurethane.

[0127] S3. The polyurethane obtained in S2 was soaked in deionized water for 12 hours and then vacuum dried at 80°C for 48 hours to obtain a room temperature self-healing polyurethane elastomer, denoted as IP-PTMG-ADH. The dried product was then pulverized and hot-pressed at 130°C for 4 minutes in a flat vulcanizing machine to obtain a dumbbell-shaped polyurethane sample of IP-PTMG-ADH.

[0128] The tensile properties of the IP-PTMG-AHD dumbbell-shaped polyurethane specimens were measured according to GB / T 528-2009. The specimens were then cut in half, and a small amount of water was applied to the cut surface. The specimens were allowed to heal at room temperature for 48 hours before being subjected to tensile testing. The test results are shown in Table 1.

[0129] According to GB / T 2410-2008, the transmittance of a 1 mm thick sample was measured. The test results are shown in Table 1. The transmittance (wavelength 600 nm) of the IP-PTMG-AHD polyurethane elastomer prepared in this embodiment is 95.2%.

[0130] Comparative Example 2

[0131] This invention provides a method for preparing a high-performance room-temperature self-healing polyurethane elastomer, comprising the following steps:

[0132] S1. Polytetramethylene ether diol (PTMG) (Mn = 2000) (20g, 10mmol) was dehydrated under vacuum at 110℃ for 2h before the reaction. The reaction system was then cooled to 70℃, and diphenylmethane diisocyanate (MDI) (5.5g, 22mmol) and 0.6mg dibutyltin dilaurate were added. The reaction was carried out at 60℃ for 2h to obtain a prepolymer with a certain viscosity.

[0133] S2. Adjust the temperature of the reaction system to 40℃, add 20mL of acetone to the prepolymer obtained in S1 to dilute the viscosity, then dissolve thiourea (THA) (0.9g, 12mmol) in 40mL of acetone and add it dropwise to the diluted prepolymer solution, and carry out the chain extension reaction for 2h to obtain polyurethane.

[0134] S3. The polyurethane obtained in S2 was soaked in deionized water for 12 hours and then vacuum dried at 80°C for 48 hours to obtain a room temperature self-healing polyurethane elastomer, denoted as M-PTMG-THA. The dried product was then pulverized and hot-pressed at 130°C for 4 minutes in a flat vulcanizing machine to obtain a dumbbell-shaped polyurethane sample of M-PTMG-THA.

[0135] The tensile properties of the M-PTMG-THA dumbbell-shaped polyurethane specimens were measured according to GB / T 528-2009. The specimens were then cut in half, and a small amount of water was applied to the cut surface. The specimens were allowed to heal at room temperature for 48 hours before being subjected to tensile testing. The test results are shown in Table 1.

[0136] According to GB / T 2410-2008, the transmittance of a 1 mm thick sample was measured. The test results are shown in Table 1. The transmittance (wavelength 600 nm) of the M-PTMG-THA polyurethane elastomer prepared in this embodiment is 43.8%.

[0137] As can be seen from Table 1, the polyurethanes prepared using asymmetric aliphatic cyclic isocyanates and chain extenders containing dynamic hydrogen bonds in Examples 1-12 all showed a repair efficiency of over 80% at room temperature for 48 hours with the assistance of trace amounts of water. However, the polyurethane prepared using a chain extender without dynamic hydrogen bonds in Comparative Example 1 did not show a good repair effect at room temperature even with the assistance of trace amounts of water. In Comparative Example 2, the polyurethane prepared using a symmetrical isocyanate containing a benzene ring structure had poor room temperature repair effect and poor transparency because the symmetrical benzene ring structure induced the crystallization of polyurethane molecular chain segments.

[0138] Table 1 Performance test results of polyurethane elastomers in Examples 1-12

[0139] Example Tensile strength (MPa) Elongation at break (%) Repair efficiency (%) at room temperature for 48 hours transparency(%) Example 1 43.2 1537.2 92.7 95.2 Example 2 34.0 2118.3 92.1 93.8 Example 3 30.7 3375.1 93.2 90.4 Example 4 36.9 2718.3 91.2 90.2 Example 5 52.3 1560.1 86.9 91.9 Example 6 37.8 2321.1 84.7 91.3 Example 7 32.8 3133.2 88.9 92.2 Example 8 40.1 2143.1 88.2 92.8 Example 9 60.3 1239.1 82.3 93.9 Example 10 41.2 2150.3 88.7 90.1 Example 11 36.7 2159.4 90.4 92.5 Example 12 43.2 2153.8 84.3 91.7 Comparative Example 1 47.1 1630.8 13.1 95.2 Comparative Example 2 41.9 1738.6 5.4 43.8

[0140] The above description of the embodiments is provided to enable those skilled in the art to understand and use the invention. It will be apparent to those skilled in the art that various modifications can be made to these embodiments, and the general principles described herein can be applied to other embodiments without inventive effort. Therefore, the present invention is not limited to the above embodiments, and any improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the invention should be within the protection scope of the present invention.

Claims

1. A high-performance room-temperature self-healing polyurethane elastomer, characterized in that, The raw materials, in molar amounts, include the following components: Diol: 10 parts; Diisocyanate: 20-26 parts; Catalyst: 0.0002~0.001 parts Dynamic hydrogen bond chain extender: 10-16 parts; Solvent: 700~1200 parts; The diisocyanate is at least one of dicyclohexylmethane diisocyanate and isophorone diisocyanate; The dynamic hydrogen bond chain extender is at least one of methylenebis(1-aminothiourea), thiourea, dimethylthiourea, and thiomethylhydrazine.

2. The high-performance room temperature self-healing polyurethane elastomer according to claim 1, characterized in that, The diol is a polyether diol or a polyester diol. The polyether diol includes at least one of polytrimethylene ether diol and polytetramethylene ether diol, and the polyester diol includes at least one of polycarbonate diol and polycaprolactone diol. The number average molecular weight of the diol is 1000~5000 g / mol.

3. The high-performance room temperature self-healing polyurethane elastomer according to claim 1, characterized in that, The catalyst is at least one of stannous octoate, tetramethylbutanediamine, and dibutyltin dilaurate.

4. The high-performance room temperature self-healing polyurethane elastomer according to claim 1, characterized in that, The solvent is at least one of toluene, N,N-dimethylformamide, acetone, butanone, N,N-dimethylacetamide, tetrahydrofuran, and dimethyl sulfoxide.

5. A method for preparing a high-performance room-temperature self-healing polyurethane elastomer according to any one of claims 1 to 4, characterized in that, Includes the following steps: S1. Dehydrate 10 parts of diol before reaction, cool the reaction system to 60~90 ℃, add 20~26 parts of diisocyanate, and react for 1~3 h under the action of 0.0002~0.001 parts of catalyst to obtain prepolymer; S2. Adjust the temperature of the reaction system to 25~70 ℃, add 200~300 parts of solvent to dilute the prepolymer obtained in S1, then dissolve 10~16 parts of dynamic hydrogen bond chain extender in 500~900 parts of solvent and add it dropwise to the prepolymer solution, carry out the chain extension reaction for 2~12 hours to obtain polyurethane. S3. The polyurethane obtained in S2 is immersed in deionized water and then vacuum dried to obtain a room temperature self-healing polyurethane elastomer.

6. The method for preparing a high-performance room-temperature self-healing polyurethane elastomer according to claim 5, characterized in that, In S1, the diol needs to be dehydrated under vacuum at 110 °C for 2-3 h before the reaction.

7. The method for preparing a high-performance room-temperature self-healing polyurethane elastomer according to claim 5, characterized in that, In S3, the polyurethane is immersed in deionized water for 12 hours.

8. The method for preparing a high-performance room-temperature self-healing polyurethane elastomer according to claim 5, characterized in that, In S3, the vacuum drying temperature is 80 °C, and the vacuum drying time is 48 h.

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