Self-healing polyurethane based on poly (epoxybutane) polyol and preparation method and application thereof

Abstract

The invention provides self-healing polyurethane based on poly (epoxybutane) polyol as well as a preparation method and application of the self-healing polyurethane. The self-healing polyurethane is prepared from the following raw materials: poly (epoxybutane) polyol, polyisocyanate, an amino chain extender and metal salt, the molecular structure of the amino chain extender contains a nitrogen heterocyclic structure; the functionality of the amino chain extender is greater than or equal to 2. In the self-healing polyurethane disclosed by the invention, the self-healing polyurethane has high self-healing efficiency and good environment resistance, and can still keep good mechanical properties in a relatively harsh environment.

Description

Technical Field

[0001] The invention belongs to the technical field of polyurethane materials, and in particular relates to a self-healing polyurethane based on poly(butylene oxide) polyol, and a preparation method and application thereof. Background Art

[0002] Polyurethane elastomers have good mechanical properties, low temperature resistance, wear resistance, and oil resistance, and are widely used in the automotive industry, shoemaking industry, aerospace, medical and health, construction and other fields. Polyurethane materials have a unique microphase separation structure, and the molecular structure of its soft segment and hard segment has an important influence on the properties of polyurethane materials. The functionalization and high performance of polyurethane materials can be achieved through molecular design. In actual use, polyurethanes often experience external damage or are used in harsh environments, such as humidity, strong acid, strong alkali, high salt, etc. These working conditions place high demands on the environmental resistance of polyurethane materials. Existing polyurethane materials cannot have both high self-healing efficiency and excellent environmental resistance.

[0003] For example, CN111763474A discloses a polyurethane transparent coating with high adhesion and environmental corrosion resistance, including coating agent A and coating agent B; coating agent A includes polyol, chain extender, catalyst, bisphenol A epoxy resin, solvent, leveling agent, wetting agent, nano titanium dioxide and antibacterial agent; coating agent B includes aliphatic diisocyanate; the polyurethane can resist various environmental corrosion; but the polyurethane does not have self-healing properties. The polyurethane with self-healing properties in the prior art generally has poor environmental resistance.

[0004] Therefore, developing a polyurethane material that has high self-healing efficiency, excellent environmental resistance, and good mechanical properties is an urgent problem to be solved in this field. Summary of the invention

[0005] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a self-healing polyurethane based on poly(butylene oxide) polyol and its preparation method and application. The self-healing polyurethane has good mechanical properties, high self-healing efficiency and good environmental resistance, and can be used in relatively harsh environments; it solves the problem of low self-healing efficiency and poor performance of existing polyurethane under harsh conditions.

[0006] To achieve this object, the present invention adopts the following technical solutions:

[0007] In a first aspect, the present invention provides a self-healing polyurethane based on poly(butylene oxide) polyol, wherein the raw materials for preparing the self-healing polyurethane include poly(butylene oxide) polyol, polyisocyanate, amino chain extender and metal salt; the molecular structure of the amino chain extender contains a nitrogen heterocyclic structure; and the functionality of the amino chain extender is ≥2.

[0008] In the present invention, poly(butylene oxide) polyol has hydrophobic properties and a long carbon chain; poly(butylene oxide) polyol is selected as the soft segment of polyurethane, which is beneficial to improving the environmental resistance and mechanical properties of polyurethane; amino chain extender is selected to form urea bond with isocyanate group, and metal salt is coordinated with nitrogen heterocycle of amino chain extender, and coordination bond is introduced into hard segment, which enhances the interaction of hydrogen bonds between urea bonds. Through coordination effect and a large number of hydrogen bonds between urea bonds, polyurethane is not only endowed with self-healing property, but also can improve the self-healing effect of polyurethane, and improve the environmental resistance of polyurethane; further, the formation of coordination bond can promote the aggregation of hard segment, increase the phase separation degree of soft and hard segment, and produce synergistic effect with the flexibility of long chain of poly(butylene oxide) polyol itself, so that the mechanical property and self-healing efficiency of polyurethane are further improved.

[0009] Preferably, the poly(butylene oxide) polyol is a homopolymer of butylene oxide.

[0010] Preferably, the average molecular weight of the poly(butylene oxide) polyol is 1000-3000 g / mol, for example, 1000 g / mol, 1200 g / mol, 1400 g / mol, 1600 g / mol, 1800 g / mol, 2000 g / mol, 2200 g / mol, 2400 g / mol, 2600 g / mol, 2800 g / mol, 3000 g / mol, etc.

[0011] Preferably, the functionality of the polyisocyanate is ≥ 2, for example, it may be 2, 3, 4, 5, 6, etc.

[0012] Preferably, the polyisocyanate includes any one or a combination of at least two of diphenylmethane diisocyanate, toluene diisocyanate, isophorone diisocyanate, 1,5-pentane diisocyanate, dicyclohexylmethane diisocyanate, hexamethylene diisocyanate, and xylylene diisocyanate; more preferably, diphenylmethane diisocyanate.

[0013] Preferably, the molar ratio of the poly(butylene oxide) polyol to the polyisocyanate is 1:(1.5-10), wherein the specific value in (1.5-10) can be, for example, 1.5, 1.6, 1.8, 2, 2.2, 2.4, 2.6, 2.8, 3, 3.2, 3.5, 3.8, 4, 4.2, 4.5, 4.8, 5, 5.2, 5.5, 5.8, 6, 6.2, 6.5, 6.8, 7, 7.2, 7.5, 7.8, 8, 8.2, 8.5, 8.8, 9, 9.2, 9.5, 9.8, 10, etc.; more preferably, it is 1:(2-5).

[0014] Preferably, the molar ratio of the amino chain extender to the poly(butylene oxide) polyol is 1:(1.5-10), wherein the specific value in (1.5-10) can be, for example, 1.5, 1.6, 1.8, 2, 2.2, 2.4, 2.6, 2.8, 3, 3.2, 3.5, 3.8, 4, 4.2, 4.5, 4.8, 5, 5.2, 5.5, 5.8, 6, 6.2, 6.5, 6.8, 7, 7.2, 7.5, 7.8, 8, 8.2, 8.5, 8.8, 9, 9.2, 9.5, 9.8, 10, etc.; more preferably, it is 1:(5.5-8.5).

[0015] Preferably, the amino chain extender comprises 2,6-diaminopyridine and / or 1,2-diaminoimidazole.

[0016] Preferably, the amino chain extender includes 2,6-diaminopyridine and 1,2-diaminoimidazole, and the molar ratio of 2,6-diaminopyridine to 1,2-diaminoimidazole is 1:(0.2-0.6), wherein the specific value in (0.2-0.6) can be, for example, 0.2, 0.22, 0.24, 0.26, 0.28, 0.3, 0.32, 0.34, 0.36, 0.38, 0.4, 0.42, 0.44, 0.46, 0.48, 0.5, 0.52, 0.54, 0.56, 0.58, 0.6, etc.

[0017] Preferably, the mass ratio of the metal salt to the amino chain extender is 1:(1-10), wherein the specific values ​​in (1-10) can be, for example, 1, 1.2, 1.4, 1.5, 1.6, 1.8, 2, 2.2, 2.4, 2.6, 2.8, 3, 3.2, 3.5, 3.8, 4, 4.2, 4.5, 4.8, 5, 5.2, 5.5, 5.8, 6, 6.2, 6.5, 6.8, 7, 7.2, 7.5, 7.8, 8, 8.2, 8.5, 8.8, 9, 9.2, 9.5, 9.8, 10, etc.; more preferably, it is 1:(2.5-4.5).

[0018] Preferably, the metal salt comprises at least one of copper trifluoromethanesulfonate, zinc trifluoromethanesulfonate, iron trifluoromethanesulfonate, copper chloride, iron chloride or zinc chloride.

[0019] In a second aspect, the present invention provides a method for preparing a self-healing polyurethane based on poly(butylene oxide) polyol according to the first aspect, the preparation method comprising the following steps:

[0020] (1) reacting poly(butylene oxide) polyol with polyisocyanate to obtain reactant A;

[0021] (2) reacting the reactant A obtained in step (1) with an amino chain extender to obtain a reactant B;

[0022] (3) reacting the reactant B obtained in step (2) with a metal salt to obtain the self-healing polyurethane.

[0023] In the present invention, step (1) further comprises the step of removing water from the poly(butylene oxide) polyol and the polyisocyanate before the reaction (the water can be removed by drying); the water content of the poly(butylene oxide) polyol and the polyisocyanate is independently less than 0.1 wt%.

[0024] Preferably, the reaction in step (1) is carried out in the presence of a protective atmosphere and a catalyst.

[0025] Preferably, the protective atmosphere comprises nitrogen.

[0026] Preferably, the catalyst comprises dibutyltin dilaurate.

[0027] Preferably, the mass of the catalyst is 0.05-0.2wt% of the total mass of the poly(butylene oxide) polyol and the polyisocyanate, for example, it can be 0.05wt%, 0.06wt%, 0.08wt%, 0.1wt%, 0.12wt%, 0.14wt%, 0.16wt%, 0.18wt%, 0.2wt%, etc.

[0028] Preferably, the reaction temperature in step (1) is 60-90°C, for example, 60°C, 65°C, 70°C, 75°C, 80°C, 85°C, 90°C, etc.

[0029] Preferably, the reaction time of step (1) is 2 to 8 hours, for example, it can be 2 hours, 3 hours, 4 hours, 5 hours, 6 hours, 7 hours, 8 hours, etc.

[0030] Preferably, the reaction in step (2) is carried out in the presence of a solvent.

[0031] Preferably, the mass ratio of the amino chain extender to the solvent is 1:(5-15), wherein the specific value of (5-15) can be, for example, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, etc.

[0032] Preferably, the solvent comprises N,N-dimethylformamide.

[0033] Preferably, the reaction temperature in step (2) is 60-90°C, for example, 60°C, 65°C, 70°C, 75°C, 80°C, 85°C, 90°C, etc.

[0034] Preferably, the reaction time of step (2) is 4 to 10 h, for example, 4 h, 5 h, 6 h, 7 h, 8 h, 9 h, 10 h, etc.

[0035] Preferably, the reaction temperature in step (3) is 40-80°C, for example, 40°C, 45°C, 50°C, 55°C, 60°C, 65°C, 70°C, 75°C, 80°C, etc.

[0036] Preferably, the reaction time of step (3) is 4 to 10 h, for example, it can be 4 h, 5 h, 6 h, 7 h, 8 h, 9 h, 10 h, etc.

[0037] In the present invention, the step (3) further comprises the step of mixing the metal salt with a solvent before the reaction; the mass ratio of the metal salt to the solvent is 1:(5-15), wherein the specific value of (5-15) can be, for example, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, etc.; and the solvent comprises N,N-dimethylformamide.

[0038] Preferably, step (3) further includes a drying step after the reaction.

[0039] Preferably, the drying temperature is 60-100°C, for example, it can be 60°C, 65°C, 70°C, 75°C, 80°C, 85°C, 90°C, 95°C, 100°C, etc.; the drying time is 24-72h, for example, it can be 24h, 28h, 32h, 36h, 40h, 44h, 48h, 52h, 56h, 60h, 64h, 68h, 72h, etc.; the vacuum degree during drying is -0.08 to -0.1MPa, for example, it can be -0.08MPa, -0.082MPa, -0.085MPa, -0.088MPa, -0.09MPa, -0.092MPa, -0.094MPa, -0.096MPa, -0.098MPa, -0.1MPa, etc.

[0040] As a preferred technical solution of the present invention, the preparation method comprises:

[0041] (1) In the presence of a protective atmosphere, poly(butylene oxide) polyol, polyisocyanate and a catalyst are mixed and reacted at 60 to 90° C. for 2 to 8 hours to obtain a reactant A;

[0042] (2) mixing the amino chain extender with the solvent, and then reacting the obtained solution with reactant A at 60 to 90° C. for 4 to 10 hours to obtain reactant B;

[0043] (3) reacting the reactant B obtained in step (2) with a metal salt at 40 to 80° C. for 4 to 10 hours, and then drying at 60 to 100° C. and -0.08 to -0.1 MPa for 24 to 72 hours to obtain the self-healing polyurethane.

[0044] In the present invention, the preparation method of the polyurethane has mild conditions and simple process.

[0045] In a third aspect, the present invention provides a self-healing material, comprising the self-healing polyurethane based on poly(butylene oxide) polyol described in the first aspect.

[0046] The numerical range described in the present invention not only includes the point values ​​listed above, but also includes any point values ​​between the above numerical ranges that are not listed. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0047] Compared with the prior art, the present invention has the following beneficial effects:

[0048] The self-healing polyurethane based on poly(butylene oxide) polyol provided by the present invention has a unique hydrophobic property of the system due to the introduction of poly(butylene oxide) polyol, so that the polyurethane has excellent tolerance in high humidity, acid and alkali corrosion, and artificial seawater environments; an amino chain extender containing a specific structure is used to form a urea bond with isocyanate, and at the same time, a coordination bond is formed by the amino chain extender and a metal salt, so that the polyurethane has good self-healing performance, and the healing efficiency is high, and it is also beneficial to improve the environmental resistance of the polyurethane. The self-healing efficiency of the polyurethane provided by the present invention is ≥80% under the condition of 80°C; the tensile strength is ≥6.7MPa, and the tensile strength retention rate after artificial seawater immersion is ≥82%; the tensile strength retention rate after acid (pH=2 hydrochloric acid aqueous solution) immersion is ≥82%; the tensile strength retention rate after alkali (pH=12 sodium hydroxide aqueous solution) immersion is ≥81%. DETAILED DESCRIPTION

[0049] The technical solution of the present invention is further described below by specific implementation methods. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0050] The materials used in the present invention can be purchased from the market or prepared by conventional methods. Unless otherwise specified, the materials used in the present invention are as follows:

[0051] Poly(butylene oxide) polyol: average molecular weight is 2000 g / mol.

[0052] Example 1

[0053] The present embodiment provides a self-healing polyurethane, wherein raw materials for preparing the self-healing polyurethane include poly(butylene oxide) polyol, diphenylmethane diisocyanate, 2,6-diaminopyridine and copper trifluoromethanesulfonate; the molar ratio of the poly(butylene oxide) polyol to diphenylmethane diisocyanate is 1:2.2, the molar ratio of the 2,6-diaminopyridine to the poly(butylene oxide) polyol is 1:6.5; the mass ratio of the copper trifluoromethanesulfonate to 2,6-diaminopyridine is 1:3.

[0054] This embodiment provides a method for preparing a self-healing polyurethane, which specifically comprises the following steps:

[0055] (1) 20 g of poly(butylene oxide) polyol and 5.56 g of diphenylmethane diisocyanate were added to a three-necked flask, followed by the addition of 0.1 wt% of dibutyltin dilaurate based on the total mass of the poly(butylene oxide) polyol and diphenylmethane diisocyanate, and the mixture was reacted at 70° C. under a nitrogen atmosphere for 3 h to obtain reactant A.

[0056] (2) Subsequently, 2,6-diaminopyridine was dissolved in N,N-dimethylformamide (the mass ratio of 2,6-diaminopyridine to N,N-dimethylformamide was 1:10), and the obtained chain extender solution was added to the reactant A obtained in step (1), and the reaction was continued at 70° C. for 6 hours to obtain reactant B.

[0057] (3) Dissolve copper trifluoromethanesulfonate in N,N-dimethylformamide (the mass ratio of copper trifluoromethanesulfonate to N,N-dimethylformamide is 1:5), add the obtained metal salt solution to the reactant B obtained in step (2), react at 60° C. for 6 hours, then place in a mold, put in a vacuum oven at 80° C. and dry for 24 hours, remove N,N-dimethylformamide, and obtain the self-healing polyurethane.

[0058] Example 2

[0059] This embodiment provides a self-healing polyurethane, which differs from Embodiment 1 only in that the diphenylmethane diisocyanate is replaced by an equimolar amount of hexamethylene diisocyanate, and other raw materials, amounts used and preparation methods are the same as those in Embodiment 1.

[0060] Example 3

[0061] This embodiment provides a self-healing polyurethane, which differs from Embodiment 1 only in that the diphenylmethane diisocyanate is replaced by an equimolar amount of isophorone diisocyanate, and other raw materials, amounts used and preparation methods are the same as those in Embodiment 1.

[0062] Example 4

[0063] This embodiment provides a self-healing polyurethane, which differs from Embodiment 1 only in that the diphenylmethane diisocyanate is replaced by an equal molar amount of 1,5-pentanediisocyanate, and other raw materials, amounts used and preparation methods are the same as those in Embodiment 1.

[0064] Example 5

[0065] The present embodiment provides a self-healing polyurethane, wherein raw materials for preparing the self-healing polyurethane include poly(butylene oxide) polyol, diphenylmethane diisocyanate, 2,6-diaminopyridine and copper trifluoromethanesulfonate; the molar ratio of the poly(butylene oxide) polyol to diphenylmethane diisocyanate is 1:4.5, the molar ratio of the 2,6-diaminopyridine to the poly(butylene oxide) polyol is 1:8.5; the mass ratio of the copper trifluoromethanesulfonate to 2,6-diaminopyridine is 1:4.5.

[0066] This embodiment provides a method for preparing a self-healing polyurethane, and the specific steps are the same as those in Embodiment 1.

[0067] Example 6

[0068] This embodiment provides a self-healing polyurethane, which differs from Embodiment 1 only in that the content of 2,6-diaminopyridine is adjusted so that the molar ratio of 2,6-diaminopyridine to poly(butylene oxide) polyol is 1:3.5, and other raw materials, amounts and preparation methods are the same as those in Embodiment 1.

[0069] Example 7

[0070] This embodiment provides a self-healing polyurethane, which differs from Embodiment 1 only in that the content of 2,6-diaminopyridine is adjusted so that the molar ratio of 2,6-diaminopyridine to poly(butylene oxide) polyol is 1:12, and other raw materials, amounts and preparation methods are the same as those in Embodiment 1.

[0071] Example 8

[0072] This embodiment provides a self-healing polyurethane, which differs from Embodiment 1 only in that the content of copper trifluoromethanesulfonate is adjusted so that the mass ratio of copper trifluoromethanesulfonate to 2,6-diaminopyridine is 1:1.5, and other raw materials, amounts and preparation methods are the same as those in Embodiment 1.

[0073] Example 9

[0074] This embodiment provides a self-healing polyurethane, which differs from Embodiment 1 only in that the content of copper trifluoromethanesulfonate is adjusted so that the mass ratio of copper trifluoromethanesulfonate to 2,6-diaminopyridine is 1:7.5, and other raw materials, amounts and preparation methods are the same as those in Embodiment 1.

[0075] Example 10

[0076] This embodiment provides a self-healing polyurethane, which differs from Embodiment 1 only in that copper trifluoromethanesulfonate is replaced by zinc trifluoromethanesulfonate of equal mass, and other raw materials, amounts used and preparation methods are the same as those in Embodiment 1.

[0077] Embodiment 11

[0078] This embodiment provides a self-healing polyurethane, which differs from Embodiment 1 only in that copper trifluoromethanesulfonate is replaced with zinc chloride of equal mass, and other raw materials, amounts used and preparation methods are the same as those in Embodiment 1.

[0079] Example 12

[0080] This embodiment provides a self-healing polyurethane, which differs from Embodiment 1 only in that 2,6-diaminopyridine is replaced by a mixture of 2,6-diaminopyridine and 1,2-diaminoimidazole in a molar ratio of 1:0.3 of equal mass, and other raw materials, amounts used and preparation methods are the same as those in Embodiment 1.

[0081] Embodiment 13

[0082] This embodiment provides a self-healing polyurethane, which differs from Embodiment 1 only in that 2,6-diaminopyridine is replaced by a mixture of 2,6-diaminopyridine and 1,2-diaminoimidazole in a molar ratio of 1:0.5 of equal mass, and other raw materials, amounts used and preparation methods are the same as those in Embodiment 1.

[0083] Embodiment 14

[0084] This embodiment provides a self-healing polyurethane, which differs from Embodiment 1 only in that 2,6-diaminopyridine is replaced by a mixture of 2,6-diaminopyridine and 1,2-diaminoimidazole in a molar ratio of 1:0.1 of equal mass, and other raw materials, amounts used and preparation methods are the same as those in Embodiment 1.

[0085] Embodiment 15

[0086] This embodiment provides a self-healing polyurethane, which differs from Embodiment 1 only in that 2,6-diaminopyridine is replaced by a mixture of 2,6-diaminopyridine and 1,2-diaminoimidazole in a molar ratio of 1:0.8 of equal mass, and other raw materials, amounts used and preparation methods are the same as those in Embodiment 1.

[0087] Example 16

[0088] This embodiment provides a self-healing polyurethane, which differs from Embodiment 1 only in that 2,6-diaminopyridine is replaced by a mixture of 2,6-diaminopyridine and 2,4-diaminopyrimidine in a molar ratio of 1:0.3 of equal mass, and other raw materials, amounts used and preparation methods are the same as those in Embodiment 1.

[0089] Comparative Example 1

[0090] This comparative example provides a self-healing polyurethane, which differs from Example 1 only in that the poly(butylene oxide) polyol is replaced by polypropylene glycol (PPG2000) of equal average molecular weight, and other raw materials, amounts and preparation methods are the same as those in Example 1.

[0091] Comparative Example 2

[0092] This comparative example provides a self-healing polyurethane, which differs from Example 1 only in that 2,6-diaminopyridine replaces an equal molar amount of 1,4-butanediol, and no copper trifluoromethanesulfonate is included in the preparation raw materials; in the preparation method, after step (2) reacts for 12 hours, the obtained solution is placed in a mold, placed in a vacuum oven at 80° C. and dried for 36 hours, and N,N-dimethylformamide is removed to obtain the self-healing polyurethane. Other raw materials, amounts and preparation methods are the same as those in Example 1.

[0093] Comparative Example 3

[0094] This comparative example provides a self-healing polyurethane, which differs from Example 1 only in that 2,6-diaminopyridine replaces an equal molar amount of 2,4-dihydroxypyridine, and other raw materials, amounts used and preparation methods are the same as those in Example 1.

[0095] Comparative Example 4

[0096] This comparative example provides a self-healing polyurethane, which differs from Example 1 only in that copper trifluoromethanesulfonate is not included in the preparation raw materials; in the preparation method, after step (2), the obtained solution is placed in a mold, placed in a vacuum oven at 80° C. and dried for 36 hours, and N,N-dimethylformamide is removed to obtain the self-healing polyurethane. Other raw materials, amounts and preparation methods are the same as those in Example 1.

[0097] Performance Testing

[0098] (1) Tensile strength: The tensile mechanical properties of the self-healing polyurethanes provided in Examples 1 to 16 and Comparative Examples 1 to 4 were tested using an electronic universal testing machine at room temperature. The polyurethane samples were cut into dumbbell shapes, with a gauge length of 12 mm (Lo), a width of 2 mm, and a thickness of 1.5 mm. The tensile rate was set to a constant strain rate of 100 mm / min. A 100 N load cell was used as the tensile mechanical sensor.

[0099] (2) Self-healing efficiency: After cutting the dumbbell-shaped polyurethane into two halves with a scalpel, the two halves of the polyurethane are brought into contact again and healed at 80°C for 24 hours without applying any external force to the specimens during the process; the self-healing efficiency is expressed by the tensile strength retention rate of the material before and after healing, and the tensile strength test method is as described above. The calculation formula for the self-healing efficiency HE is as follows: Where HE represents the self-healing efficiency, σ self healed represents the tensile strength after healing, σ original It represents the initial tensile strength (i.e. the tensile strength of the material before self-healing).

[0100] (3) Environmental resistance: 50 mL of hydrochloric acid solution with pH = 2, sodium hydroxide solution with pH = 12 and artificial seawater (Shanghai MacLean Biochemical Technology Co., Ltd., A769002) were respectively taken into glassware, and then the prepared polyurethane sample was immersed in it for 72 hours. The immersed polyurethane was subjected to tensile test according to method (1), and the environmental resistance was represented by the tensile strength retention rate of the material before and after immersion. The tensile strength retention rate CE was calculated according to the following formula: Where, CE represents the tensile strength retention rate, σ corroded Indicates the tensile strength of the material after immersion, σ original Indicates the initial tensile strength.

[0101] The specific test results are shown in Table 1.

[0102] Table 1

[0103]

[0104] As shown in Table 1, the self-healing polyurethane based on poly(butylene oxide) polyol provided by the present invention has good mechanical properties, high self-healing efficiency and good environmental corrosion resistance by selecting specific raw materials, that is, selecting poly(butylene oxide) polyol as the soft segment, and introducing urea bonds and coordination bonds into the hard segment. The self-healing polyurethane heals at 80°C for 24 hours, and the self-healing efficiency reaches 80-99%; the tensile strength can reach 6.7-10.9MPa, and the tensile strength retention rate after artificial seawater immersion is 82-99%; the tensile strength retention rate after acid (pH=2 hydrochloric acid aqueous solution) immersion is 82-97%; the tensile strength retention rate after alkali (pH=12 sodium hydroxide aqueous solution) immersion is 81-98%.

[0105] By comparing Example 1, Example 2, Example 3 and Example 4, it can be seen that under the same conditions, the polyurethane prepared using diphenylmethane diisocyanate has higher mechanical strength and higher self-healing efficiency, and also has a higher tensile strength retention rate after acid, alkali and artificial seawater corrosion.

[0106] By comparing Example 1 and Comparative Example 1, it can be seen that under the same reaction conditions, the polyurethane obtained by using poly(butylene oxide) polyol as a raw material has better corrosion resistance and mechanical properties.

[0107] By comparing Example 1 with Comparative Examples 2 to 4, it can be seen that under the same conditions, by using an amino chain extender with a specific structure and adding a metal salt to the raw materials to form a coordination bond with the amino chain extender, the obtained polyurethane has higher self-healing efficiency and better corrosion resistance.

[0108] In summary, the present invention can give the self-healing polyurethane good mechanical properties, achieve excellent corrosion resistance, and improve the healing efficiency of the self-healing polyurethane by selecting specific raw materials, adopting simple polymerization conditions and simple post-treatment.

[0109] The specific embodiments described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific 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 protection scope of the present invention.

Claims

1. A self-healing polyurethane based on poly(butylene oxide) polyol, characterized in that The raw materials for preparing the self-healing polyurethane include poly(butylene oxide) polyol, polyisocyanate, amino chain extender and metal salt; The amino chain extender contains a nitrogen heterocyclic structure in its molecular structure; The functionality of the amino chain extender is ≥2.

2. The self-healing polyurethane based on poly(butylene oxide) polyol according to claim 1, characterized in that The poly(butylene oxide) polyol is a homopolymer of butylene oxide; Preferably, the average molecular weight of the poly(butylene oxide) polyol is 1000 to 3000 g / mol.

3. The self-healing polyurethane based on poly(butylene oxide) polyol according to claim 1 or 2, characterized in that The functionality of the polyisocyanate is ≥2; Preferably, the polyisocyanate includes any one or a combination of at least two of diphenylmethane diisocyanate, toluene diisocyanate, isophorone diisocyanate, 1,5-pentane diisocyanate, dicyclohexylmethane diisocyanate, hexamethylene diisocyanate, and xylylene diisocyanate; Preferably, the molar ratio of the poly(butylene oxide) polyol to the polyisocyanate is 1:(1.5-10), more preferably 1:(2-5).

4. The self-healing polyurethane based on poly(butylene oxide) polyol according to any one of claims 1 to 3, characterized in that The molar ratio of the amino chain extender to the poly(butylene oxide) polyol is 1:(1.5-10), more preferably 1:(5.5-8.5); Preferably, the amino chain extender comprises 2,6-diaminopyridine and / or 1,2-diaminoimidazole; Preferably, the amino chain extender comprises 2,6-diaminopyridine and 1,2-diaminoimidazole, and the molar ratio of the 2,6-diaminopyridine to the 1,2-diaminoimidazole is 1:(0.2-0.6).

5. The self-healing polyurethane based on poly(butylene oxide) polyol according to any one of claims 1 to 4, characterized in that The mass ratio of the metal salt to the amino chain extender is 1:(1-10), more preferably 1:(2.5-4.5); Preferably, the metal salt comprises at least one of copper trifluoromethanesulfonate, zinc trifluoromethanesulfonate, iron trifluoromethanesulfonate, copper chloride, iron chloride or zinc chloride.

6. A method for preparing a self-healing polyurethane based on poly(butylene oxide) polyol according to any one of claims 1 to 5, characterized in that: The preparation method comprises the following steps: (1) reacting poly(butylene oxide) polyol with polyisocyanate to obtain reactant A; (2) reacting the reactant A obtained in step (1) with an amino chain extender to obtain a reactant B; (3) reacting the reactant B obtained in step (2) with a metal salt to obtain the self-healing polyurethane.

7. The preparation method according to claim 6, characterized in that: The reaction in step (1) is carried out in the presence of a protective atmosphere and a catalyst; Preferably, the protective atmosphere comprises nitrogen; Preferably, the catalyst comprises dibutyltin dilaurate; Preferably, the mass of the catalyst is 0.05-0.2 wt% of the total mass of the poly(butylene oxide) polyol and the polyisocyanate; Preferably, the reaction temperature in step (1) is 60-90°C; Preferably, the reaction time in step (1) is 2 to 8 hours.

8. The preparation method according to claim 6 or 7, characterized in that: The reaction in step (2) is carried out in the presence of a solvent; Preferably, the mass ratio of the amino chain extender to the solvent is 1:(5-15); Preferably, the solvent comprises N,N-dimethylformamide; Preferably, the reaction temperature in step (2) is 60-90°C; Preferably, the reaction time in step (2) is 4 to 10 hours.

9. The preparation method according to any one of claims 6 to 8, characterized in that: The reaction temperature in step (3) is 40 to 80°C; Preferably, the reaction time in step (3) is 4 to 10 hours; Preferably, step (3) further comprises a drying step after the reaction; Preferably, the drying temperature is 60 to 100° C., the drying time is 24 to 72 hours, and the vacuum degree during drying is -0.08 to -0.1 MPa.

10. A self-repairing material, characterized in that: The self-healing material comprises the self-healing polyurethane based on poly(butylene oxide) polyol according to any one of claims 1 to 5.

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