Polyurethane with self-repairing and lasting fragrance as well as preparation method and application of polyurethane

Abstract

The invention discloses polyurethane with self-repairing and lasting fragrance as well as a preparation method and application thereof, and the preparation method comprises the following steps: step 1, mixing tris (2-aminoethyl) amine and vanillin or vanillin derivative solution, and fully reacting to obtain three-functional-group Schiff base; step 2, melting the dihydric alcohol prepolymer, adding diisocyanate under a protective atmosphere condition, and fully reacting to obtain an isocyanate-terminated prepolymer; and step 3, slowly dropwise adding the trifunctional Schiff base solution obtained in the step 1 into the isocyanate-terminated prepolymer obtained in the step 2, and fully reacting to obtain the required polyurethane. The polyurethane obtained by the invention has good self-repairing performance and excellent mechanical properties, and also has antibacterial and anti-inflammatory effects.

Description

Technical Field

[0001] The invention relates to the technical field of polyurethane, and in particular to a polyurethane with self-repairing and lasting fragrance, a preparation method and application thereof. Background Art

[0002] Polyurethane is a polymer material synthesized from polyisocyanate and terminal hydroxyl compounds. Due to its excellent mechanical properties, wear resistance and resilience, it is widely used in coatings, adhesives, elastomers and foam materials. During processing, transportation and use, polyurethane will inevitably be subjected to physical (ultraviolet rays, heat, stress, etc.) or chemical effects, resulting in scratches or cracks on the surface of the polyurethane material, which will reduce its mechanical properties and seriously affect the safety and service life of the material. Self-healing materials are materials that utilize the self-healing mechanism of the material and have the ability to restore the initial performance without human help or intervention after damage. The existence of this self-healing ability not only prolongs the service life of the material and reduces costs, but also avoids waste of resources and environmental pollution. Vanillin, also known as vanillin, is an organic compound extracted from vanilla beans, an orchid plant. Vanillin has the aroma of vanilla beans and a strong milky aroma, which plays a role in flavoring and fixing. It is widely used in industries such as cosmetics, tobacco, cakes, candies and baked goods. It is one of the synthetic fragrances with the largest production in the world.

[0003] Existing polyurethanes such as the publication number CN112979919A, a method for preparing a bio-based self-healing polyurethane elastomer, furfurylamine and formaldehyde undergo a condensation reaction in the presence of hydrochloric acid, and then undergo an aldehyde amine condensation with vanillin to obtain a small molecule chain extender containing a dynamic imine bond, and then undergo a chain extension reaction with a polyurethane prepolymer prepared from diphenylmethane diisocyanate and polypropylene glycol to obtain a polyurethane elastomer. However, the self-healing efficiency of this polyurethane at 60°C is only 87%, and the elongation at break is only 220%. The publication number CN117645553A, a bio-based chain extender containing Schiff base and a covalently adaptive polyurethane elastomer prepared therefrom, in a nitrogen atmosphere, vegetable oil and diisocyanate are reacted in an organic solvent to obtain a polyurethane prepolymer solution; the polyurethane prepolymer solution, the chain extender solution and the catalyst are mixed, and the covalently adaptive polyurethane elastomer is obtained after the reaction; however, the chain extender used is a compound of betulin and Schiff base, which affects the self-healing efficiency of the polyurethane to a certain extent. Summary of the invention

[0004] In view of the problems existing in the prior art, the present invention provides a polyurethane with self-repairing and lasting fragrance, a preparation method and application thereof.

[0005] The technical solution adopted by the present invention is:

[0006] A polyurethane with self-repairing and lasting fragrance, the structure of which is as follows:

[0007]

[0008] Where: U is a diisocyanate residue, R 1 is a soft segment, is a diol prepolymer residue, TSB is a trifunctional Schiff base residue, and x is any integer from 10 to 100;

[0009] The trifunctional Schiff base residue is formed by the reaction of tri(2-aminoethyl)amine and vanillin or its derivatives.

[0010] Furthermore, the trifunctional Schiff base residue structure is as follows:

[0011]

[0012] Where: R 2 is any one of -H, -CH3, -OCH3, -CN, R 3 and R 4 Each is one of -H and -CH3.

[0013] Furthermore, the diol prepolymer residue is obtained by polymerization of ε-caprolactone monomer, and the number average molecular weight of the diol prepolymer is 1 to 10 kg / mol.

[0014] Furthermore, the diisocyanate residue is obtained by reacting diisocyanate with a prepolymer corresponding to the soft segment; wherein the diisocyanate is one or a mixture of two or more of 4,4'-dimethylmethane diisocyanate, 1,6-hexamethylene diisocyanate, L-lysine diisocyanate and isophorone diisocyanate.

[0015] A method for preparing polyurethane comprises the following steps:

[0016] Step 1: mixing tri(2-aminoethyl)amine and vanillin or its derivative solution, and fully reacting to obtain a trifunctional Schiff base;

[0017] Step 2: Melting the diol prepolymer, adding diisocyanate under protective atmosphere, and obtaining an isocyanate-terminated prepolymer after sufficient reaction;

[0018] Step 3: Slowly drop the trifunctional Schiff base solution obtained in step 1 into the isocyanate-terminated prepolymer obtained in step 2, and the desired polyurethane can be obtained after sufficient reaction.

[0019] Furthermore, the reaction temperature in step 1 is 78° C., and the reaction time is 2 to 5 hours.

[0020] Furthermore, the molar ratio of the diol prepolymer, the diisocyanate and the trifunctional Schiff base is 1:2:0.67 to 1:10:6.

[0021] An application of polyurethane, wherein the polyurethane is used as a self-repairing material and a medical device material.

[0022] The beneficial effects of the present invention are:

[0023] (1) The polyurethane obtained by the present invention is a dual dynamically cross-linked polyurethane having an imide bond in the main chain. The imide bond in the main chain can form an intermolecular hydrogen bond with a part of the carbonyl group in the carbamate bond, and can also form an intramolecular hydrogen bond with a part of the carbonyl group, so that the hydrogen bond physical cross-linking network is more dense, thereby affecting the strength and toughness of the polyurethane material.

[0024] (2) The polyurethane obtained by the present invention has good self-repairing properties. The chain extender used contains a reversible imine bond. After the surface is damaged, the imine bond will undergo a reversible transformation reaction under heating or pH influence;

[0025] (3) The polyurethane material obtained by the present invention has antibacterial and anti-inflammatory effects, is beneficial to wound healing, and has a lasting fragrance, and has the potential to be used as a self-repairing medical device. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 Schematic diagram of stress-strain curves of the polyurethane materials obtained in Examples 3 to 5 of the present invention.

[0027] Figure 2 This is a diagram of the self-repairing process of the polyurethane material obtained in Example 6 of the present invention, a is the sample, b is the sample after shearing, c is the sample after heating, d is the sample stretched again after self-repair, and e and f are schematic diagrams of load-bearing after self-repair.

[0028] Figure 3 This is a schematic diagram of the stress-strain curve of the polyurethane material obtained in Example 6 of the present invention.

[0029] Figure 4 This is a schematic diagram comparing the surface scratches of the sample of comparative example 1 of the present invention before and after repair.

[0030] Figure 5 This is a complete photo of the sample of comparative example 2 of the present invention after cutting, splicing and healing.

[0031] Figure 6 Schematic diagram of the stress-strain curve of the sample of comparative example 2 of the present invention before and after self-repair. DETAILED DESCRIPTION

[0032] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

[0033] A polyurethane with self-repairing and lasting fragrance, the structure of which is as follows:

[0034]

[0035] Where: U is a diisocyanate residue, R 1 is a soft segment, is a diol prepolymer residue, TSB is a trifunctional Schiff base residue, and x is any integer from 10 to 100;

[0036] The trifunctional Schiff base residue is formed by the reaction of tri(2-aminoethyl)amine and vanillin or its derivatives.

[0037] The structure of the trifunctional Schiff base residue is as follows:

[0038]

[0039] Where: R 2 is any one of -H, -CH3, -OCCH3, -CN, R 3 and R 4 Each is one of -H and -CH3.

[0040] The diol prepolymer residue is obtained by polymerization of ε-caprolactone monomer, and the number average molecular weight of the diol prepolymer is 1-10 kg / mol. The diisocyanate residue is obtained by reaction of diisocyanate with the corresponding prepolymer of the soft segment; wherein the diisocyanate is one of 4,4'-dimethylmethane diisocyanate, 1,6-hexamethylene diisocyanate, L-lysine diisocyanate, and isophorone diisocyanate, or a mixture of two or more thereof.

[0041] A method for preparing polyurethane comprises the following steps:

[0042] Step 1: Mix tri(2-aminoethyl)amine and vanillin or its derivative solution, and fully react to obtain a trifunctional Schiff base; the reaction temperature is 78°C, and the reaction time is 2 to 5 hours. The crude trifunctional Schiff base product is recrystallized, filtered, dried, and weighed to obtain a trifunctional Schiff base product, which is prepared in ultra-dry N,N-dimethylformamide (DMF) and dimethyl sulfoxide (DMSO) solvents at a concentration of 0.1 to 2.0 g / mL for standby use.

[0043] Step 2: Melting the diol prepolymer, adding diisocyanate under protective atmosphere, and obtaining an isocyanate-terminated prepolymer after sufficient reaction;

[0044] Step 3: Slowly drop the trifunctional Schiff base solution obtained in step 1 into the isocyanate-terminated prepolymer obtained in step 2, and the desired polyurethane can be obtained after sufficient reaction. The molar ratio of diol prepolymer, diisocyanate, and trifunctional Schiff base is 1:2:0.67 to 1:10:6.

[0045] Example 1

[0046] The following steps were followed to prepare polyurethane with self-healing, long-lasting fragrance.

[0047] Step 1: Dissolve tri(2-aminoethyl)amine and vanillin in ethanol respectively, mix the two and react them fully, and reflux at 78°C for 4 hours to obtain a crude trifunctional Schiff base product, wherein R 2 For H, R 3 and R 4 Both are H.

[0048] The crude trifunctional Schiff base product is recrystallized in a low temperature environment below 0°C, filtered, dried, and weighed to obtain a purified Schiff base, which is then prepared into a Schiff base solution with a concentration of 0.25 g / mL.

[0049] Step 2: Add polycaprolactone diol prepolymer with a number average molecular weight of 1.0 kg / mol into the reactor, remove water for 6 hours under a vacuum degree of 100 Pa, and replace the vacuum nitrogen three times. After the water removal is completed, the diol prepolymer is melted in an 80°C oil bath under nitrogen protection.

[0050] Under protective atmosphere conditions, 1,6-hexamethylene diisocyanate with a terminal hydroxyl molar weight of 2.0 / 1 (the molar ratio of 1,6-hexamethylene diisocyanate to polycaprolactone diol prepolymer is 2.0 / 1) is added, and the isocyanate-terminated prepolymer is obtained after reacting in an oil bath at 80° C. for 3 hours.

[0051] Step 3: slowly drop the isocyanate-terminated prepolymer obtained in step 2 into the DMF solution of the trifunctional Schiff base obtained in step 1 (wherein the molar amount of the terminal hydroxyl group of the trifunctional Schiff base is 0.67 / 1, that is, the molar ratio of the trifunctional Schiff base to the polycaprolactone diol prepolymer is 0.67 / 1), react in an 80°C oil bath for 2 hours to obtain a viscous liquid, transfer the above viscous liquid to a polytetrafluoroethylene mold while hot, put it in an 80°C oven, let it stand for 48 hours to evaporate a large amount of solvent, and then put it in a vacuum oven to dry at room temperature for 12 hours to evaporate and remove the residual solvent in the film to obtain a polyurethane film of uniform thickness.

[0052] Example 2

[0053] The following steps were followed to prepare polyurethane with self-healing, long-lasting fragrance.

[0054] Step 1: Dissolve tri(2-aminoethyl)amine and vanillin derivative in ethanol respectively, mix the two and react them fully, and reflux at 78°C for 4 hours to obtain a crude trifunctional Schiff base product, wherein R 2 -CN, R 3 and R 4 Both are H.

[0055] The crude trifunctional Schiff base product was recrystallized in a low temperature environment below 0°C, and after filtration, drying, and constant weight, a purified Schiff base was obtained, which was then prepared into a Schiff base solution with a concentration of 2.0 g / mL.

[0056] Step 2: Add polycaprolactone diol prepolymer with a number average molecular weight of 2.0 kg / mol into the reactor, remove water for 6 hours under a vacuum degree of 100 Pa, and replace the vacuum nitrogen three times. After the water removal is completed, the diol prepolymer is melted in an 80°C oil bath under nitrogen protection.

[0057] Under protective atmosphere conditions, 1,6-hexamethylene diisocyanate with a terminal hydroxyl molar weight of 2.0 / 1 (the molar ratio of 1,6-hexamethylene diisocyanate to polycaprolactone diol prepolymer is 2.0 / 1) is added, and the isocyanate-terminated prepolymer is obtained after reacting in an oil bath at 80° C. for 3 hours.

[0058] Step 3: slowly drop the isocyanate-terminated prepolymer obtained in step 2 into the DMSO solution of the trifunctional Schiff base obtained in step 1 (wherein the molar amount of the terminal hydroxyl group of the trifunctional Schiff base is 0.67 / 1, that is, the molar ratio of the trifunctional Schiff base to the polycaprolactone diol prepolymer is 0.67 / 1), react in an 80°C oil bath for 2 hours to obtain a viscous liquid, transfer the above viscous liquid to a polytetrafluoroethylene mold while hot, put it in an 80°C oven, let it stand for 48 hours to evaporate a large amount of solvent, and then put it in a vacuum oven to dry at room temperature for 12 hours to evaporate and remove the residual solvent in the film to obtain a polyurethane film of uniform thickness.

[0059] Example 3

[0060] The following steps were followed to prepare polyurethane with self-healing, long-lasting fragrance.

[0061] Step 1: Dissolve tri(2-aminoethyl)amine and vanillin derivative in ethanol respectively, mix the two and react them fully, and reflux at 78°C for 4 hours to obtain a crude trifunctional Schiff base product, wherein R 2 For -OCH3, R 3 and R 4 Both are H.

[0062] The crude trifunctional Schiff base product is recrystallized in a low temperature environment below 0°C, filtered, dried, and weighed to obtain a purified Schiff base, which is then prepared into a Schiff base solution with a concentration of 0.25 g / mL.

[0063] Step 2: Add polycaprolactone diol prepolymer with a number average molecular weight of 3.0 kg / mol into the reactor, remove water for 6 hours under a vacuum degree of 100 Pa, and replace the vacuum nitrogen three times. After the water removal is completed, the diol prepolymer is melted in an 80°C oil bath under nitrogen protection.

[0064] Under protective atmosphere conditions, 1,6-hexamethylene diisocyanate with a terminal hydroxyl molar weight of 2.0 / 1 (the molar ratio of 1,6-hexamethylene diisocyanate to polycaprolactone diol prepolymer is 2.0 / 1) is added, and the isocyanate-terminated prepolymer is obtained after reacting in an oil bath at 80° C. for 3 hours.

[0065] Step 3: slowly drop the isocyanate-terminated prepolymer obtained in step 2 into the DMSO solution of the trifunctional Schiff base obtained in step 1 (wherein the molar amount of the terminal hydroxyl group of the trifunctional Schiff base is 0.67 / 1, that is, the molar ratio of the trifunctional Schiff base to the polycaprolactone diol prepolymer is 0.67 / 1), react in an 80°C oil bath for 2 hours to obtain a viscous liquid, transfer the above viscous liquid to a polytetrafluoroethylene mold while hot, put it in an 80°C oven, let it stand for 48 hours to evaporate a large amount of solvent, and then put it in a vacuum oven to dry at room temperature for 12 hours to evaporate and remove the residual solvent in the film to obtain a polyurethane film of uniform thickness.

[0066] Example 4

[0067] The following steps were followed to prepare polyurethane with self-healing, long-lasting fragrance.

[0068] Step 1: Dissolve tri(2-aminoethyl)amine and vanillin derivative in ethanol respectively, mix the two and react them fully, and reflux at 78°C for 4 hours to obtain a crude trifunctional Schiff base product, wherein R 2 For -OCH3, R 3 and R 4 Both are H.

[0069] The crude trifunctional Schiff base product is recrystallized in a low temperature environment below 0°C, filtered, dried, and weighed to obtain a purified Schiff base, which is then prepared into a Schiff base solution with a concentration of 0.25 g / mL.

[0070] Step 2: Add polycaprolactone diol prepolymer with a number average molecular weight of 3.0 kg / mol into the reactor, remove water for 6 hours under a vacuum degree of 100 Pa, and replace the vacuum nitrogen three times. After the water removal is completed, the diol prepolymer is melted in an 80°C oil bath under nitrogen protection.

[0071] Under protective atmosphere conditions, 1,6-hexamethylene diisocyanate with a terminal hydroxyl molar weight of 3.0 / 1 (the molar ratio of 1,6-hexamethylene diisocyanate to polycaprolactone diol prepolymer is 3.0 / 1) is added, and the isocyanate-terminated prepolymer is obtained after reacting in an oil bath at 80° C. for 3 hours.

[0072] Step 3: slowly drop the isocyanate-terminated prepolymer obtained in step 2 into the DMSO solution of the trifunctional Schiff base obtained in step 1 (wherein the molar amount of the terminal hydroxyl group of the trifunctional Schiff base is 1.34 / 1, that is, the molar ratio of the trifunctional Schiff base to the polycaprolactone diol prepolymer is 1.34 / 1), react in an 80°C oil bath for 2 hours to obtain a viscous liquid, transfer the above viscous liquid to a polytetrafluoroethylene mold while hot, put it in an 80°C oven, let it stand for 48 hours to evaporate a large amount of solvent, and then put it in a vacuum oven to dry at room temperature for 12 hours to evaporate and remove the residual solvent in the film to obtain a polyurethane film of uniform thickness.

[0073] Example 5

[0074] The following steps were followed to prepare polyurethane with self-healing, long-lasting fragrance.

[0075] Step 1: Dissolve tri(2-aminoethyl)amine and vanillin derivative in ethanol respectively, mix the two and react them fully, and reflux at 78°C for 4 hours to obtain a crude trifunctional Schiff base product, wherein R 2 For -OCH3, R 3 and R 4 Both are H.

[0076] The crude trifunctional Schiff base product is recrystallized in a low temperature environment below 0°C, filtered, dried, and weighed to obtain a purified Schiff base, which is then prepared into a Schiff base solution with a concentration of 0.25 g / mL.

[0077] Step 2: Add polycaprolactone diol prepolymer with a number average molecular weight of 3.0 kg / mol into the reactor, remove water for 6 hours under a vacuum degree of 100 Pa, and replace the vacuum nitrogen three times. After the water removal is completed, the diol prepolymer is melted in an 80°C oil bath under nitrogen protection.

[0078] Under protective atmosphere conditions, 1,6-hexamethylene diisocyanate with a terminal hydroxyl molar weight of 4.0 / 1 (the molar ratio of 1,6-hexamethylene diisocyanate to polycaprolactone diol prepolymer is 4.0 / 1) is added, and the isocyanate-terminated prepolymer is obtained after reacting in an oil bath at 80° C. for 3 hours.

[0079] Step 3: Slowly drop the isocyanate-terminated prepolymer obtained in step 2 into the DMSO solution of the trifunctional Schiff base obtained in step 1 (wherein the molar amount of the terminal hydroxyl group of the trifunctional Schiff base is 2.0 / 1, that is, the molar ratio of the trifunctional Schiff base to the polycaprolactone diol prepolymer is 2.0 / 1), react in an 80°C oil bath for 2 hours to obtain a viscous liquid, transfer the above viscous liquid to a polytetrafluoroethylene mold while hot, put it in an 80°C oven, let it stand for 48 hours to evaporate a large amount of solvent, and then put it in a vacuum oven to dry at room temperature for 12 hours to evaporate and remove the residual solvent in the film to obtain a polyurethane film of uniform thickness.

[0080] Example 6

[0081] The following steps were followed to prepare polyurethane with self-healing, long-lasting fragrance.

[0082] Step 1: Dissolve tri(2-aminoethyl)amine and vanillin in ethanol respectively, mix the two and react them fully, and reflux at 78°C for 4 hours to obtain a crude trifunctional Schiff base product, wherein R 2 For H, R 3 and R 4 Both are H.

[0083] The crude trifunctional Schiff base product is recrystallized in a low temperature environment below 0°C, filtered, dried, and weighed to obtain a purified Schiff base, which is then prepared into a Schiff base solution with a concentration of 0.1 g / mL.

[0084] Step 2: Add polycaprolactone diol prepolymer with a number average molecular weight of 2.0 kg / mol into the reactor, remove water for 6 hours under a vacuum degree of 100 Pa, and replace the vacuum nitrogen three times. After the water removal is completed, the diol prepolymer is melted in an 80°C oil bath under nitrogen protection.

[0085] Under protective atmosphere conditions, 1,6-hexamethylene diisocyanate with a terminal hydroxyl molar weight of 2.0 / 1 (the molar ratio of 1,6-hexamethylene diisocyanate to polycaprolactone diol prepolymer is 2.0 / 1) is added, and the isocyanate-terminated prepolymer is obtained after reacting in an oil bath at 80° C. for 3 hours.

[0086] Step 3: slowly drop the isocyanate-terminated prepolymer obtained in step 2 into the DMF solution of the trifunctional Schiff base obtained in step 1 (wherein the molar amount of the terminal hydroxyl group of the trifunctional Schiff base is 0.67 / 1, that is, the molar ratio of the trifunctional Schiff base to the polycaprolactone diol prepolymer is 0.67 / 1), react in an 80°C oil bath for 2 hours to obtain a viscous liquid, transfer the above viscous liquid to a polytetrafluoroethylene mold while hot, put it in an 80°C oven, let it stand for 48 hours to evaporate a large amount of solvent, and then put it in a vacuum oven to dry at room temperature for 12 hours to evaporate and remove the residual solvent in the film to obtain a polyurethane film of uniform thickness.

[0087] Example 7

[0088] The following steps were followed to prepare polyurethane with self-healing, long-lasting fragrance.

[0089] Step 1: Dissolve tri(2-aminoethyl)amine and vanillin derivative in ethanol respectively, mix the two and react them fully, and reflux at 78°C for 4 hours to obtain a crude trifunctional Schiff base product, wherein R 2 -CH3, R 3 and R 4 Both are H.

[0090] The crude trifunctional Schiff base product is recrystallized in a low temperature environment below 0°C, filtered, dried, and weighed to obtain a purified Schiff base, which is then prepared into a Schiff base solution with a concentration of 0.5 g / mL.

[0091] Step 2: Add polycaprolactone diol prepolymer with a number average molecular weight of 5.0 kg / mol into the reactor, remove water for 6 hours under a vacuum degree of 100 Pa, and replace the vacuum nitrogen three times. After the water removal is completed, the diol prepolymer is melted in an 80°C oil bath under nitrogen protection.

[0092] Under protective atmosphere conditions, isophorone diisocyanate with a terminal hydroxyl molar weight of 5.0 / 1 (the molar ratio of isophorone diisocyanate to polycaprolactone diol prepolymer is 5.0 / 1) is added, and the isocyanate-terminated prepolymer is obtained after reacting in an oil bath at 80° C. for 3 hours.

[0093] Step 3: slowly drop the isocyanate-terminated prepolymer obtained in step 2 into the DMSO solution of the trifunctional Schiff base obtained in step 1 (wherein the molar amount of the terminal hydroxyl group of the trifunctional Schiff base is 2.67 / 1, that is, the molar ratio of the trifunctional Schiff base to the polycaprolactone diol prepolymer is 2.67 / 1), react in an 80°C oil bath for 2 hours to obtain a viscous liquid, transfer the above viscous liquid to a polytetrafluoroethylene mold while hot, put it in an 80°C oven, let it stand for 48 hours to evaporate a large amount of solvent, and then put it in a vacuum oven to dry at room temperature for 12 hours to evaporate and remove the residual solvent in the film to obtain a polyurethane film of uniform thickness.

[0094] Example 8

[0095] The following steps were followed to prepare polyurethane with self-healing, long-lasting fragrance.

[0096] Step 1: Dissolve tri(2-aminoethyl)amine and vanillin derivative in ethanol respectively, mix the two and react them fully, and reflux at 78°C for 2h to obtain a crude trifunctional Schiff base product, wherein R 2 -CH3, R 3 and R 4 Both are H.

[0097] The crude trifunctional Schiff base product is recrystallized in a low temperature environment below 0°C, filtered, dried, and weighed to obtain a purified Schiff base, which is then prepared into a Schiff base solution with a concentration of 0.5 g / mL.

[0098] Step 2: Add polycaprolactone diol prepolymer with a number average molecular weight of 1.0 kg / mol into the reactor, remove water for 6 hours under a vacuum degree of 100 Pa, and replace the vacuum nitrogen three times. After the water removal is completed, the diol prepolymer is melted in an 80°C oil bath under nitrogen protection.

[0099] Under protective atmosphere conditions, isophorone diisocyanate with a terminal hydroxyl molar weight of 8.0 / 1 (the molar ratio of isophorone diisocyanate to polycaprolactone diol prepolymer is 8.0 / 1) is added, and the isocyanate-terminated prepolymer is obtained after reacting in an oil bath at 80° C. for 3 hours.

[0100] Step 3: slowly drop the isocyanate-terminated prepolymer obtained in step 2 into the DMSO solution of the trifunctional Schiff base obtained in step 1 (wherein the molar amount of the terminal hydroxyl group of the trifunctional Schiff base is 4.67 / 1, that is, the molar ratio of the trifunctional Schiff base to the polycaprolactone diol prepolymer is 4.67 / 1), react in an 80°C oil bath for 2 hours to obtain a viscous liquid, transfer the above viscous liquid to a polytetrafluoroethylene mold while hot, put it in an 80°C oven, let it stand for 48 hours to evaporate a large amount of solvent, and then put it in a vacuum oven to dry at room temperature for 12 hours to evaporate and remove the residual solvent in the film to obtain a polyurethane film of uniform thickness.

[0101] Example 9

[0102] The following steps were followed to prepare polyurethane with self-healing, long-lasting fragrance.

[0103] Step 1: Dissolve tri(2-aminoethyl)amine and vanillin derivative in ethanol respectively, mix the two and react them fully, and reflux at 78°C for 5 hours to obtain a crude trifunctional Schiff base product, wherein R 2 -CH3, R 3 and R 4 Both are H.

[0104] The crude trifunctional Schiff base product was recrystallized in a low temperature environment below 0°C, filtered, dried, and weighed to obtain a purified Schiff base, which was then prepared into a Schiff base solution with a concentration of 1.0 g / mL.

[0105] Step 2: Add polycaprolactone diol prepolymer with a number average molecular weight of 4.0 kg / mol into the reactor, remove water for 6 hours under a vacuum degree of 100 Pa, and replace the vacuum nitrogen three times. After the water removal is completed, the diol prepolymer is melted in an 80°C oil bath under nitrogen protection.

[0106] Under protective atmosphere conditions, 4,4'-dimethylmethane diisocyanate with a terminal hydroxyl molar weight of 10.0 / 1 (the molar ratio of 4,4'-dimethylmethane diisocyanate to polycaprolactone diol prepolymer is 10.0 / 1) was added, and the isocyanate-terminated prepolymer was obtained after reacting in an oil bath at 80°C for 3 hours.

[0107] Step 3: Slowly drop the isocyanate-terminated prepolymer obtained in step 2 into the DMSO solution of the trifunctional Schiff base obtained in step 1 (wherein the molar amount of the terminal hydroxyl group of the trifunctional Schiff base is 6.0 / 1, that is, the molar ratio of the trifunctional Schiff base to the polycaprolactone diol prepolymer is 6.0 / 1), react in an 80°C oil bath for 2 hours to obtain a viscous liquid, transfer the above viscous liquid to a polytetrafluoroethylene mold while hot, put it in an 80°C oven, let it stand for 48 hours to evaporate a large amount of solvent, and then put it in a vacuum oven to dry at room temperature for 12 hours to evaporate and remove the residual solvent in the film to obtain a polyurethane film of uniform thickness.

[0108] Example 10

[0109] The following steps were followed to prepare polyurethane with self-healing, long-lasting fragrance.

[0110] Step 1: Dissolve tri(2-aminoethyl)amine and vanillin derivative in ethanol respectively, mix the two and react them fully, and reflux at 78°C for 4 hours to obtain a crude trifunctional Schiff base product, wherein R 2 -CH3, R 3 and R 4 Both are H.

[0111] The crude trifunctional Schiff base product was recrystallized in a low temperature environment below 0°C, and after filtration, drying, and constant weight, a purified Schiff base was obtained, which was then prepared into a Schiff base solution with a concentration of 2.0 g / mL.

[0112] Step 2: Add polycaprolactone diol prepolymer with a number average molecular weight of 6.0 kg / mol into the reactor, remove water for 6 hours under a vacuum degree of 100 Pa, and replace the vacuum nitrogen three times. After the water removal is completed, the diol prepolymer is melted in an 80°C oil bath under nitrogen protection.

[0113] Under protective atmosphere conditions, 4,4'-dimethylmethane diisocyanate with a terminal hydroxyl molar weight of 7.0 / 1 (the molar ratio of 4,4'-dimethylmethane diisocyanate to polycaprolactone diol prepolymer is 7.0 / 1) is added, and the isocyanate-terminated prepolymer is obtained after reacting in an oil bath at 80°C for 3 hours.

[0114] Step 3: slowly drop the isocyanate-terminated prepolymer obtained in step 2 into the DMSO solution of the trifunctional Schiff base obtained in step 1 (wherein the molar amount of the terminal hydroxyl group of the trifunctional Schiff base is 4.0 / 1, that is, the molar ratio of the trifunctional Schiff base to the polycaprolactone diol prepolymer is 4.0 / 1), react in an 80°C oil bath for 2 hours to obtain a viscous liquid, transfer the above viscous liquid to a polytetrafluoroethylene mold while hot, put it in an 80°C oven, let it stand for 48 hours to evaporate a large amount of solvent, and then put it in a vacuum oven to dry at room temperature for 12 hours to evaporate and remove the residual solvent in the film to obtain a polyurethane film of uniform thickness.

[0115] Embodiment 11

[0116] The following steps were followed to prepare polyurethane with self-healing, long-lasting fragrance.

[0117] Step 1: Dissolve tri(2-aminoethyl)amine and vanillin derivative in ethanol respectively, mix the two and react them fully, and reflux at 78°C for 4 hours to obtain a crude trifunctional Schiff base product, wherein R 2 -CH3, R 3 and R 4 Both are H.

[0118] The crude trifunctional Schiff base product is recrystallized in a low temperature environment below 0°C, filtered, dried, and weighed to obtain a purified Schiff base, which is then prepared into a Schiff base solution with a concentration of 0.1 g / mL.

[0119] Step 2: Add polycaprolactone diol prepolymer with a number average molecular weight of 5.0 kg / mol into the reactor, remove water for 6 hours under a vacuum degree of 100 Pa, and replace the vacuum nitrogen three times. After the water removal is completed, the diol prepolymer is melted in an 80°C oil bath under nitrogen protection.

[0120] Under protective atmosphere conditions, L-lysine diisocyanate with a terminal hydroxyl molar weight of 2.0 / 1 (the molar ratio of L-lysine diisocyanate to polycaprolactone diol prepolymer is 2.0 / 1) is added, and the isocyanate-terminated prepolymer is obtained after reacting in an 80° C. oil bath for 3 hours.

[0121] Step 3: slowly drop the isocyanate-terminated prepolymer obtained in step 2 into the DMSO solution of the trifunctional Schiff base obtained in step 1 (wherein the molar amount of the terminal hydroxyl group of the trifunctional Schiff base is 0.67 / 1, that is, the molar ratio of the trifunctional Schiff base to the polycaprolactone diol prepolymer is 0.67 / 1), react in an 80°C oil bath for 2 hours to obtain a viscous liquid, transfer the above viscous liquid to a polytetrafluoroethylene mold while hot, put it in an 80°C oven, let it stand for 48 hours to evaporate a large amount of solvent, and then put it in a vacuum oven to dry at room temperature for 12 hours to evaporate and remove the residual solvent in the film to obtain a polyurethane film of uniform thickness.

[0122] Example 12

[0123] The following steps were followed to prepare polyurethane with self-healing, long-lasting fragrance.

[0124] Step 1: Dissolve tri(2-aminoethyl)amine and vanillin derivative in ethanol respectively, mix the two and react them fully, and reflux at 78°C for 4 hours to obtain a crude trifunctional Schiff base product, wherein R 2 For H, R 3 and R 4 Both are H.

[0125] The crude trifunctional Schiff base product is recrystallized in a low temperature environment below 0°C, filtered, dried, and weighed to obtain a purified Schiff base, which is then prepared into a Schiff base solution with a concentration of 0.1 g / mL.

[0126] Step 2: Add polycaprolactone diol prepolymer with a number average molecular weight of 1.0 kg / mol into the reactor, remove water for 6 hours under a vacuum degree of 100 Pa, and replace the vacuum nitrogen three times. After the water removal is completed, the diol prepolymer is melted in an 80°C oil bath under nitrogen protection.

[0127] Under protective atmosphere conditions, L-lysine diisocyanate with a terminal hydroxyl molar weight of 10.0 / 1 (the molar ratio of L-lysine diisocyanate to polycaprolactone diol prepolymer is 10.0 / 1) was added, and the isocyanate-terminated prepolymer was obtained after reacting in an 80° C. oil bath for 3 hours.

[0128] Step 3: slowly drop the isocyanate-terminated prepolymer obtained in step 2 into the DMF solution of the trifunctional Schiff base obtained in step 1 (wherein the molar amount of the terminal hydroxyl group of the trifunctional Schiff base is 6.0 / 1, that is, the molar ratio of the trifunctional Schiff base to the polycaprolactone diol prepolymer is 6.0 / 1), react in an 80°C oil bath for 2 hours to obtain a viscous liquid, transfer the above viscous liquid to a polytetrafluoroethylene mold while hot, put it in an 80°C oven, let it stand for 48 hours to evaporate a large amount of solvent, and then put it in a vacuum oven to dry at room temperature for 12 hours to evaporate and remove the residual solvent in the film to obtain a polyurethane film of uniform thickness.

[0129] Embodiment 13

[0130] The following steps were followed to prepare polyurethane with self-healing, long-lasting fragrance.

[0131] Step 1: Dissolve tri(2-aminoethyl)amine and vanillin derivative in ethanol respectively, mix the two and react them fully, and reflux at 78°C for 4 hours to obtain a crude trifunctional Schiff base product, wherein R 2 For H, R 3 and R 4 Both are H.

[0132] The crude trifunctional Schiff base product was recrystallized in a low temperature environment below 0°C, and after filtration, drying, and constant weight, a purified Schiff base was obtained, which was then prepared into a Schiff base solution with a concentration of 0.9 g / mL.

[0133] Step 2: Add polycaprolactone diol prepolymer with a number average molecular weight of 7.0 kg / mol into the reactor, remove water for 6 hours under a vacuum degree of 100 Pa, and replace the vacuum nitrogen three times. After the water removal is completed, the diol prepolymer is melted in an 80°C oil bath under nitrogen protection.

[0134] Under protective atmosphere conditions, 4,4'-dimethylmethane diisocyanate with a terminal hydroxyl molar weight of 2.0 / 1 (the molar ratio of 4,4'-dimethylmethane diisocyanate to polycaprolactone diol prepolymer is 2.0 / 1) is added, and the isocyanate-terminated prepolymer is obtained after reacting in an oil bath at 80°C for 3 hours.

[0135] Step 3: slowly drop the isocyanate-terminated prepolymer obtained in step 2 into the DMSO solution of the trifunctional Schiff base obtained in step 1 (wherein the molar amount of the terminal hydroxyl group of the trifunctional Schiff base is 0.67 / 1, that is, the molar ratio of the trifunctional Schiff base to the polycaprolactone diol prepolymer is 0.67 / 1), react in an 80°C oil bath for 2 hours to obtain a viscous liquid, transfer the above viscous liquid to a polytetrafluoroethylene mold while hot, put it in an 80°C oven, let it stand for 48 hours to evaporate a large amount of solvent, and then put it in a vacuum oven to dry at room temperature for 12 hours to evaporate and remove the residual solvent in the film to obtain a polyurethane film of uniform thickness.

[0136] In order to illustrate the performance of the polyurethane obtained by the present invention, the obtained samples were subjected to static tensile and self-repair performance tests, and the test methods are as follows:

[0137] Static tensile test: The mechanical properties were tested using a Taiwan High Speed ​​Rail Testing Instruments Company U60 universal material testing machine. The sensor load was 200N and the samples were cut into dumbbell-shaped strips with a cutter for testing. The tensile rate was 10mm / min. Each sample was tested more than 3 times and the average value was taken.

[0138] Self-healing performance test:

[0139] Qualitative repair test: Use a blade to completely cut the rectangular spline from the middle, then contact the two sections, keep them under a certain pressure for 1 minute, and then put the spline in an oven at 80°C for a certain time. Then take out the spline and use a digital camera to record digital photos of the material surface at a certain temperature and time. Use the repaired spline to lift a 500mL glass bottle or a 500g weight, and the spline does not break, indicating that the polyurethane material has good self-healing properties.

[0140] Quantitative repair test: Use a blade to completely cut the rectangular spline from the middle, then contact the two sections, keep them under a certain pressure for 1 minute, and then put the spline into an oven at 80°C for a certain period of time. Then take out the spline for mechanical property testing. The test conditions are the same as the static tensile test. Each sample is tested at least 3 times in parallel, and the final data is averaged. The formula for calculating the repair rate of mechanical properties is as follows:

[0141]

[0142] Among them, σ original represents the tensile strength of the initial sample, σ healed Represents the tensile strength after repair; ε original represents the elongation at break of the initial sample, ε healed Represents the elongation at break after repair, η σ is the repair efficiency of tensile strength, η εThe repair efficiency is the elongation at break.

[0143] The mechanical properties of the polyurethane materials obtained in Examples 3 to 5 were tested using the above method. The results are as follows: Figure 1 And as shown in Table 1.

[0144] Table 1. Mechanical properties data of samples of Examples 3 to 5

[0145]

[0146] From Table 1 and Figure 1 It can be seen that, under the same molecular weight of polycaprolactone diol prepolymer, adjusting the content of isocyanate and Schiff base chain extender can obtain polyurethane materials with excellent mechanical properties, and their elongation at break is greater than 1000%, and the fracture stress is between 18.89 and 20.61 MPa, indicating that the polyurethane has excellent mechanical properties and meets the strength and toughness requirements of pancreatic drainage tube materials. In addition, the fracture strength of Schiff base modified polyurethane can be customized by adjusting the molecular weight of polycaprolactone diol prepolymer to meet the physical and chemical performance requirements of biological tissues without causing a certain degree of tissue damage.

[0147] According to the above self-repairing test method, the self-repairing performance test of the polyurethane sample in Example 6 was carried out. The results are as follows Figure 2 and Figure 3 , and as shown in Table 2.

[0148] Table 2. Mechanical properties of samples in the initial state and after repair at 80°C for different time periods

[0149]

[0150] The polyurethane sample obtained by cutting the sample in half in Example 6 was placed in an oven at 80°C for 10 minutes, and the cut marks on the surface of the sample basically disappeared. The repaired polyurethane sample was subjected to a tensile test, and it was found that the tensile strength and elongation at break of the repaired sample were 13.26MPa and 1091% respectively, and the repair efficiency of the tensile strength and elongation at break reached more than 90%. It can be seen that the use of trifunctional Schiff base as the only chain extender to modify polyurethane can obtain a polyurethane material with excellent mechanical properties and high self-repairing efficiency.

[0151] Comparative Example 1

[0152] The other steps of this comparative example are the same as those of Example 1, except that step 1 is not included, and the Schiff base in step 3 is replaced by 1,4-butanediol BDO.

[0153] The self-healing test results are as follows: Figure 4 As shown, Figure 4In the figure, a is the image before restoration, and b is the image after restoration.

[0154] When the polyurethane obtained in this comparative example has scratches or cracks on the surface, the damaged sample is placed in an oven at 80°C for 1 hour, but the scratches or cracks on the sample surface do not heal or disappear. This is because this type of polyurethane structure does not contain dynamic imide bonds, so the material cannot be well repaired.

[0155] Comparative Example 2

[0156] The other steps of this comparative example are the same as those of Example 1, except that step 1 is not included, and the Schiff base in step 3 is replaced by a chain extender obtained by compounding 1,4-butanediol BDO and vanillin Schiff base.

[0157] The self-healing test results are as follows Figure 5 and Figure 6 As shown in the figure, it can be seen that although the sample obtained in this comparative example can have the function of self-repair, the self-repair efficiency is low. After the comparative sample 2 is cut in half, reconnected and heated at 80°C for 24 hours, the two samples can be re-healed into a rectangular spline ( Figure 5 ), which shows that this type of polyurethane has self-repairing function, but by comparing the mechanical properties before and after repair, it can be found that the self-repair of this type of polyurethane sample is only 77%, such as Figure 6 shown.

[0158] This is mainly because when Schiff base and BDO are used as a compound chain extender, the hard segment in the polyurethane structure is composed of Schiff base, BDO and isocyanate. In addition, the Schiff base itself contains a large sterically hindered benzene ring structure. In the chain extension reaction, the small molecule BDO is preferentially extended, and then the Schiff base participates in the chain extension. The amount of Schiff base introduced is limited, resulting in a low content of imine bonds on the polyurethane main chain. Therefore, the reversible exchange efficiency of imine bonds during the heating healing process is limited, making its self-healing efficiency low. However, we use trifunctional Schiff base as the only chain extender to modify the dual dynamic cross-linked polyurethane. The hard segment in the polyurethane structure is completely composed of Schiff base and isocyanate. The large number of imine bonds on the main chain improves the reversible exchange efficiency of the healing process. In addition, the imine bonds on the main chain can form intramolecular hydrogen bonds with some carbonyl groups in addition to intermolecular hydrogen bonds with some carbonyl groups in the carbamate bonds. The hydrogen bond physical cross-linking network is more dense, so that it can complete more efficient self-healing in a shorter time.

[0159] The present invention uses a trifunctional Schiff base as a chain extender to modify polyurethane, and synthesizes a dual dynamic cross-linked polyurethane containing an imide bond in the polyurethane main chain. Therefore, the hard segment in the polyurethane structure is completely composed of Schiff base and isocyanate. In addition to forming intermolecular hydrogen bonds with part of the carbonyl groups in the carbamate bonds, a large number of imide bonds on the main chain can also form intramolecular hydrogen bonds with part of the carbonyl groups, making the hydrogen bond physical cross-linking network more compact, thereby affecting the strength and toughness of the polyurethane material. At the same time, the trifunctional Schiff base structure contains a large number of large sterically hindered benzene ring structures and different substituents, which can effectively destroy the crystallization of polyurethane. The physical and chemical properties of the polyurethane material such as strength and hardness can be customized by adjusting the amount of Schiff base introduced. In addition, the softness and hardness and mechanical properties of the material can be freely regulated by adjusting the chain length and content of the soft segment in the polyurethane structure to match it with the application occasion.

[0160] The obtained polyurethane material has good self-repairing function. When the polyurethane is subjected to dynamic and static loads for a long time during use, scratches, microcracks or structural damage are generated on its surface, the damaged original polyurethane is heated in an oven at 40 to 80°C, and the original appearance and original performance can be restored within 20 minutes to 12 hours, thereby extending the service life of the material. This is because the present invention uses a trifunctional Schiff base as the only chain extender to modify the polyurethane, rather than using a compound chain extender. The hard segment in the polyurethane structure is completely composed of Schiff base and isocyanate, and the Schiff base structure contains a reversible imine bond. After the sample surface is damaged, the imine bond breaks. When the sample is spliced ​​together, the imine bond in the cross section will undergo a reversible exchange reaction under the influence of heating or pH, and the old bond and the new bond are generated, so that the chain ends are re-spliced ​​together to achieve the effect of self-healing and self-repairing. In addition, the self-repairing function of the polyurethane material can be customized by adjusting the content of the trifunctional Schiff base in the polyurethane structure, the molecular weight of the soft segment, etc., to extend the service life of the material.

[0161] The polyurethane obtained by the present invention not only has antibacterial and anti-inflammatory functions, which can be beneficial to wound healing, but also has a lasting fragrance, which can eliminate odors in surgery or wards, and has the potential to be used as a self-repairing medical device.

Claims

1. A polyurethane with self-repairing and lasting fragrance, characterized in that: Its structure is as follows: Where: U is a diisocyanate residue, R 1 is a soft segment, is a diol prepolymer residue, TSB is a trifunctional Schiff base residue, and x is any integer from 10 to 100; The trifunctional Schiff base residue is formed by the reaction of tri(2-aminoethyl)amine and vanillin or its derivatives.

2. The polyurethane with self-repairing and lasting fragrance according to claim 1, characterized in that: The trifunctional Schiff base residue structure is as follows: Where: R 2 is any one of -H, -CH3, -OCH3, -CN, R 3 and R 4 Each is one of -H and -CH3.

3. The polyurethane with self-repairing and lasting fragrance according to claim 1, characterized in that: The diol prepolymer residue is obtained by polymerization of ε-caprolactone monomer, and the number average molecular weight of the diol prepolymer is 1-10 kg / mol.

4. The polyurethane with self-repairing and lasting fragrance according to claim 1, characterized in that: The diisocyanate residue is obtained by reacting diisocyanate with a prepolymer corresponding to the soft segment; wherein the diisocyanate is one or a mixture of two or more of 4,4'-dimethylmethane diisocyanate, 1,6-hexamethylene diisocyanate, L-lysine diisocyanate and isophorone diisocyanate.

5. The method for preparing a polyurethane according to any one of claims 1 to 4, characterized in that: The following steps are involved: Step 1: mixing tri(2-aminoethyl)amine and vanillin or its derivative solution, and fully reacting to obtain a trifunctional Schiff base; Step 2: Melting the diol prepolymer, adding diisocyanate under protective atmosphere, and obtaining an isocyanate-terminated prepolymer after sufficient reaction; Step 3: Slowly drop the trifunctional Schiff base solution obtained in step 1 into the isocyanate-terminated prepolymer obtained in step 2, and the desired polyurethane can be obtained after sufficient reaction.

6. The method for preparing polyurethane according to claim 5, characterized in that: The reaction temperature in step 1 is 78° C. and the reaction time is 2 to 5 hours.

7. The method for preparing polyurethane according to claim 5, characterized in that: The molar ratio of the diol prepolymer, the diisocyanate and the trifunctional Schiff base is 1:2:0.67 to 1:10:

6.

8. The use of any one of the polyurethanes of claims 1 to 4, characterized in that: The polyurethane is used as a self-repairing material and a medical device material.

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