Polyurethane sealing material and preparation method thereof

Abstract

The present invention provides a polyurethane sealing material and a preparation method thereof. The preparation method of the polyurethane sealing material provided by the present invention comprises the following steps: a) reacting a polyol with an isocyanate to obtain an isocyanate-terminated polyurethane prepolymer A; b) mixing the isocyanate-terminated polyurethane prepolymer A with a mechanical interlocking molecule to obtain a reaction product B; c) mixing the isocyanate-terminated polyurethane prepolymer A with the reaction product B and a chain extender to obtain a polyurethane sealing material; the mechanical interlocking molecule is a 2-(hydroxymethyl)-12-crown-4-ether and a platinum (II) complex of bipyridine carboxylate. The polyurethane sealing material provided by the present invention can make the polyurethane have high elasticity and rapid recovery performance, and also maintain strong dynamic wear resistance in a dynamic and harsh environment.

Description

Technical Field

[0001] The invention relates to the field of organic materials, and in particular to a polyurethane sealing material and a preparation method thereof. Background Art

[0002] Sealing materials can not only buffer the collision of the connection parts, but also prevent external objects from splashing or penetrating into the equipment and causing damage to it. However, the sealing materials of large-scale equipment are mainly imported, and it is urgent to break through the foreign technical blockade and realize localization.

[0003] Compared with static equipment, when sealing materials are used in dynamic and complex construction environments, they not only need to have strong deformation and rapid recovery capabilities, but their wear resistance is also an important parameter for measuring the effectiveness and life of sealing materials.

[0004] Sealing materials are generally made of rubber materials, but their hardness and friction coefficient are relatively large. When used as dynamic sealing materials, problems such as poor sealing effect or inflexible equipment connections may occur. Therefore, it is necessary to develop a new material to solve the above problems.

[0005] As a high-strength, high-toughness and wear-resistant polymer material, polyurethane has shown great potential in the field of dynamic sealing. Although some polyurethane sealing materials have been developed, they are not enough in the fields of dynamic and high wear resistance. Dynamic sealing materials have harsh operating environments, and their sizes and models are diverse and limited. They have high requirements for material design and are difficult to develop. The dynamic and complex operating environment has high requirements for the comprehensive performance of the materials, making it difficult for existing sealing materials to meet the requirements. Summary of the invention

[0006] In view of this, the present invention provides a polyurethane sealing material and a preparation method thereof. The polyurethane sealing material provided by the present invention can make the polyurethane have high elasticity and rapid recovery performance, and at the same time, maintain strong dynamic wear resistance in dynamic and harsh environments.

[0007] The present invention provides a method for preparing a polyurethane sealing material, comprising the following steps:

[0008] a) reacting a polyol with an isocyanate to obtain an isocyanate-terminated polyurethane prepolymer A;

[0009] b) mixing and reacting the terminal isocyanate polyurethane prepolymer A with the mechanical interlocking molecules to obtain a reaction product B;

[0010] c) mixing the isocyanate-terminated polyurethane prepolymer A with the reaction product B and a chain extender to obtain a polyurethane sealing material;

[0011] The mechanical interlocking molecule is a complex of 2-(hydroxymethyl)-12-crown 4-ether and bipyridine carboxylic acid platinum (II).

[0012] Preferably, the mass ratio of the 2-(hydroxymethyl)-12-crown 4-ether to the bipyridine carboxylic acid platinum (II) complex is (5-10):1.

[0013] Preferably, in step b), the reaction temperature is 100-130°C.

[0014] Preferably, in step b), the amount of the mechanically interlocking molecules used is 2 wt% to 8 wt% of the total amount of the substances used in step b).

[0015] Preferably, in step c), the chain extender is ethylene glycol and / or resorcinol bis(2-hydroxyethyl) ether.

[0016] Preferably, in step c), the mass ratio of the isocyanate-terminated polyurethane prepolymer A to the reaction product B is preferably 1:(0.2-1),

[0017] The amount of the chain extender used is 2 wt% to 10 wt% of the total amount of the substances used in step c).

[0018] Preferably, in step c), the mixing temperature is 100-130°C.

[0019] Preferably, in step a):

[0020] The polyol is at least one of polycarbonate polyol, polycaprolactone polyol, polytetramethylene glycol polyol and polypropylene oxide polyol;

[0021] The isocyanate is at least one of hexamethylene diisocyanate, naphthalene diisocyanate, diphenylmethane diisocyanate, toluene diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate and triphenylmethane triisocyanate.

[0022] Preferably, in step a):

[0023] The molar ratio of -OH in the polyol to -NCO in the isocyanate is 1:(1.5-3);

[0024] The reaction temperature is 60-90° C. and the reaction time is 2-6 hours.

[0025] The present invention provides a polyurethane sealing material prepared by the preparation method described in the above technical scheme.

[0026] The preparation method provided by the present invention comprises the following steps: reacting a polyol with an isocyanate to obtain an isocyanate-terminated polyurethane prepolymer A; mixing and reacting the isocyanate-terminated polyurethane prepolymer A with a mechanical interlocking molecule to obtain a reaction product B; and then mixing the isocyanate-terminated polyurethane prepolymer A with the reaction product B and a chain extender to obtain a polyurethane sealing material; wherein the mechanical interlocking molecule is a specific 2-(hydroxymethyl)-12-crown 4-ether and bipyridine platinum (II) complex. In the above preparation process of the present invention, after adding the mechanical interlocking molecules, the platinum (II) bipyridine carboxylate complex will form a large six-membered ring, and the ring structure formed by 2-(hydroxymethyl)-12-crown 4-ether will be embedded in the dynamic six-membered macrocyclic ring, thereby forming a dynamic and cross-linked interlocking structure, which improves the mechanical properties of the product while further increasing its dynamic wear resistance; after the introduction of the chain extender, the molecular chain of the prepolymer will increase rapidly, thereby increasing the degree of entanglement and cohesive energy between the polyurethane molecules, and cooperate with the dynamic and cross-linked interlocking structure of the previous step, resulting in an increase in its strength and excellent shape recovery ability. Therefore, through the above method, the toughness and rapid recovery performance of the polyurethane sealing material (that is, it can quickly recover to its original shape in a short time after deformation) can be effectively improved, and at the same time, its dynamic wear resistance can also be improved, so that it can maintain strong dynamic wear resistance in a dynamic and harsh environment.

[0027] The test results show that the polyurethane sealing material provided by the present invention has a tensile strength of more than 50 MPa, a wear coefficient in a dynamic wear resistance test of less than 0.88, and a rebound value in shape recovery of more than 95%, showing excellent toughness, dynamic wear resistance and shape recovery. DETAILED DESCRIPTION

[0028] The present invention provides a method for preparing a polyurethane sealing material, comprising the following steps:

[0029] a) reacting a polyol with an isocyanate to obtain an isocyanate-terminated polyurethane prepolymer A;

[0030] b) mixing and reacting the terminal isocyanate polyurethane prepolymer A with the mechanical interlocking molecules to obtain a reaction product B;

[0031] c) mixing the isocyanate-terminated polyurethane prepolymer A with the reaction product B and a chain extender to obtain a polyurethane sealing material;

[0032] The mechanical interlocking molecule is a complex of 2-(hydroxymethyl)-12-crown 4-ether and bipyridine carboxylic acid platinum (II).

[0033] Regarding step a) :

[0034] a) polyol reacts with isocyanate to obtain isocyanate-terminated polyurethane prepolymer A.

[0035] In the present invention, the polyol is preferably at least one of polycarbonate polyol, polycaprolactone polyol, polytetramethylene glycol polyol and polypropylene oxide polyol.

[0036] In the present invention, the isocyanate is preferably at least one of hexamethylene diisocyanate, naphthalene diisocyanate, diphenylmethane diisocyanate, toluene diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate and triphenylmethane triisocyanate.

[0037] In the present invention, the amount of the polyol and the isocyanate is expressed by the ratio of -OH in the polyol to -NCO in the isocyanate. Specifically, the molar ratio of -OH in the polyol to -NCO in the isocyanate is preferably 1:(1.5-3), specifically 1:1.5, 1:2, 1:2.5, 1:3.

[0038] In the present invention, before the reaction, the polyol is preferably heated to remove water. In the present invention, the heating to remove water is preferably carried out under a protective atmosphere. The present invention has no special restrictions on the type of gas providing a protective atmosphere, and it can be a conventional protective gas well known to those skilled in the art, such as nitrogen, argon, etc. In the present invention, the temperature of the heating to remove water is preferably 100-140°C, specifically 100°C, 110°C, 120°C, 130°C, 140°C, and more preferably 120°C. The time for the heating to remove water is preferably 1-4h, specifically 1h, 2h, 3h, 4h, and more preferably 2h.

[0039] In the present invention, after the above treatment, the polyol is mixed with the isocyanate for reaction. In the present invention, the reaction is preferably carried out under a protective atmosphere. The present invention has no special restrictions on the type of gas providing the protective atmosphere, and it can be a conventional protective gas well known to those skilled in the art, such as nitrogen, argon, etc. In the present invention, the reaction temperature is preferably 60 to 90°C, specifically 60°C, 65°C, 70°C, 75°C, 80°C, 85°C, 90°C. The reaction time is preferably 2 to 6h, specifically 2h, 3h, 4h, 5h, 6h. After the above reaction, an isocyanate-terminated polyurethane prepolymer A is obtained.

[0040] In the present invention, step a) preferably specifically comprises: adding polyol into a reactor, heating under nitrogen protection to remove water; then, adding isocyanate, heating to the reaction temperature under nitrogen protection to react, and obtaining an isocyanate-terminated polyurethane prepolymer A. The isocyanate-terminated polyurethane prepolymer refers to a polyurethane prepolymer with isocyanate groups (-NCO) at both end groups.

[0041] Regarding step b) :

[0042] b) mixing and reacting the terminal isocyanate polyurethane prepolymer A with the mechanical interlocking molecules to obtain a reaction product B.

[0043] In the present invention, the mechanical interlocking molecule is 2-(hydroxymethyl)-12-crown 4-ether and platinum (II) bipyridine carboxylate complex. Compared with other molecules, the use of the above-mentioned specific type of mechanical interlocking molecules in the present invention is conducive to achieving the expected effect of the present invention. Taking 2-(hydroxymethyl)-12-crown 4-ether as an example, the above-mentioned ether containing hydroxyl groups can further react with the polyurethane prepolymer containing terminal isocyanate groups with a certain degree of chain extension, thereby covalently connecting the 2-(hydroxymethyl)-12-crown 4-ether containing a small ring to the main chain of the polyurethane molecule, and then cross-linking with the platinum (II) bipyridine carboxylate complex of a dynamic macrocycle to form a dynamic mechanical interlocking structure. If 2-(hydroxymethyl)-12-crown 4-ether is replaced by a pure crown ether molecule, the crown ether will not be introduced into the main chain of the polyurethane. The mechanical interlocking structure finally formed not only fails to play a dynamic interlocking and cross-linking role on the polyurethane molecule, but will lead to a decrease in product performance due to its poor compatibility with polyurethane.

[0044] In the present invention, the mass ratio of the 2-(hydroxymethyl)-12-crown 4-ether to the platinum (II) bipyridine carboxylate complex is preferably (5-10):1, specifically 5:1, 6:1, 7:1, 8:1, 9:1, 10:1. In the present invention, the amount of the mechanical interlocking molecules is preferably 2wt% to 8wt% of the total amount of the substances in step b), specifically 2wt%, 3wt%, 4wt%, 5wt%, 6wt%, 7wt%, 8wt%. Wherein, the total substances in step b) refer to all substances added in step b), namely, the terminal isocyanate polyurethane prepolymer A and the mechanical interlocking molecules.

[0045] In the present invention, the reaction is preferably carried out under a protective atmosphere. The present invention has no particular limitation on the type of gas providing the protective atmosphere, and any conventional protective gas well known to those skilled in the art may be used, such as nitrogen, argon, and the like.

[0046] In the present invention, the reaction temperature is preferably 100-130° C., specifically 100° C., 105° C., 110° C., 115° C., 120° C., 125° C., 130° C. The reaction time is preferably 30-60 min, specifically 30 min, 40 min, 50 min, 60 min. After the above reaction, a reaction product B is obtained.

[0047] In the present invention, the letters "A" and "B" in the isocyanate-terminated polyurethane prepolymer A obtained in step a) and the reaction product B obtained in step b) have no special meaning or limitation. A is not a limitation on the type of the isocyanate-terminated polyurethane prepolymer (i.e., it does not refer to a specific substance in the isocyanate-terminated polyurethane prepolymer), and B is not a limitation on the type of the reaction product obtained in step b). A and B may also be directly omitted. For example, step a) may be written as obtaining an isocyanate-terminated polyurethane prepolymer, and step b) may be written as obtaining a reaction product. The letters A and B are added in the present invention only to mark the products obtained in step a) and step b), respectively, so as to facilitate intuitive identification of the products obtained in which respective steps correspond.

[0048] Regarding step c) :

[0049] c) mixing the isocyanate-terminated polyurethane prepolymer A with the reaction product B and a chain extender to obtain a polyurethane sealing material.

[0050] In the present invention, the mass ratio of the terminal isocyanate polyurethane prepolymer A to the reaction product B is preferably 1:(0.2-1), specifically 1:0.2, 1:0.3, 1:0.4, 1:0.5, 1:0.6, 1:0.7, 1:0.8, 1:0.9, 1:1.0.

[0051] In the present invention, the chain extender is preferably ethylene glycol and / or resorcinol di(2-hydroxyethyl) ether. In the present invention, the amount of the chain extender is preferably 2wt% to 10wt% of the total amount of the substance in step c), specifically 2wt%, 3wt%, 4wt%, 5wt%, 6wt%, 7wt%, 8wt%, 9wt%, 10wt%. Wherein, the total substance in step c) refers to all substances added in step c), i.e., the terminal isocyanate polyurethane prepolymer A, the reaction product B and the chain extender.

[0052] In the present invention, the method of mixing the terminal isocyanate polyurethane prepolymer A, the reaction product B and the chain extender is preferably: firstly mix the terminal isocyanate polyurethane prepolymer A and the reaction product B, and then add the chain extender for mixing. The temperature for mixing after adding the chain extender is preferably 100-130°C, specifically 100°C, 110°C, 120°C, 130°C. The mixing time is preferably 1-2h, specifically 1h, 2h. Mixing is performed under the above heating conditions so that the materials are vulcanized during the mixing process.

[0053] In the present invention, after the above mixing, it is preferred to further perform casting and cooling to obtain the polyurethane sealing material. Specifically, after uniform mixing, the obtained mixture is cast in a mold of a certain shape, then cooled at room temperature, and then demoulded to obtain a polyurethane sealing material with a desired shape.

[0054] In the present invention, the isocyanate-terminated polyurethane prepolymer A is used in both step b) and step c). Specifically, after the isocyanate-terminated polyurethane prepolymer A is obtained in step a), it can be divided into several parts and used in step b) and step c) respectively; it can also be that after the isocyanate-terminated polyurethane prepolymer A is obtained in step a), it is used in step b), and then some isocyanate-terminated polyurethane prepolymer A is prepared and used in step c); or other usage methods are also possible, mainly ensuring that it can be used in both step b) and step c).

[0055] The present invention also provides a polyurethane sealing material prepared by the preparation method described in the above technical solution. The polyurethane sealing material provided by the present invention is a mechanically interlocking dynamic high wear-resistant polyurethane sealing material.

[0056] The preparation method provided by the present invention comprises the following steps: reacting a polyol with an isocyanate to obtain an isocyanate-terminated polyurethane prepolymer A; mixing and reacting the isocyanate-terminated polyurethane prepolymer A with a mechanical interlocking molecule to obtain a reaction product B; and then mixing the isocyanate-terminated polyurethane prepolymer A with the reaction product B and a chain extender to obtain a polyurethane sealing material; wherein the mechanical interlocking molecule is a specific 2-(hydroxymethyl)-12-crown 4-ether and bipyridine platinum (II) complex. In the above preparation process of the present invention, after adding the mechanical interlocking molecules, the platinum (II) bipyridine carboxylate complex will form a large six-membered ring, and the ring structure formed by 2-(hydroxymethyl)-12-crown 4-ether will be embedded in the dynamic six-membered macrocyclic ring, thereby forming a dynamic and cross-linked interlocking structure, which improves the mechanical properties of the product while further increasing its dynamic wear resistance; after the introduction of the chain extender, the molecular chain of the prepolymer will increase rapidly, thereby increasing the degree of entanglement and cohesive energy between the polyurethane molecules, and cooperate with the dynamic and cross-linked interlocking structure of the previous step, resulting in an increase in its strength and excellent shape recovery ability. Therefore, through the above method, the toughness and rapid recovery performance of the polyurethane sealing material (that is, it can quickly recover to its original shape in a short time after deformation) can be effectively improved, and at the same time, its dynamic wear resistance can also be improved, so that it can maintain strong dynamic wear resistance in a dynamic and harsh environment.

[0057] The present invention has the following beneficial effects: 1. The polyurethane material has high tensile strength; 2. The polyurethane material can quickly recover to its original shape in a short time after deformation; 3. This polyurethane material is suitable for large-scale production and is suitable for sealing products with complex shapes and sizes; 4. The dynamic wear resistance is high, ensuring a sufficient service life.

[0058] The test results show that the polyurethane sealing material provided by the present invention has a tensile strength of more than 50 MPa, a wear coefficient in a dynamic wear resistance test of less than 0.88, and a rebound value in shape recovery of more than 95%, showing excellent toughness, dynamic wear resistance and shape recovery.

[0059] In order to further understand the present invention, preferred embodiments of the present invention are described below in conjunction with examples. However, it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, rather than limiting the claims of the present invention.

[0060] Example 1

[0061] a) 30 parts of polycaprolactone polyol were added into a reactor, and water was removed at 120° C. for 2 h under nitrogen protection. Then, 60 parts of hexamethylene diisocyanate (the molar ratio of -OH in the polyol to -NCO in the isocyanate was 1:2) were added, and the mixture was heated to 70° C. for reaction for 4 h under continuous nitrogen protection to obtain an isocyanate-terminated polyurethane prepolymer A.

[0062] b) Mixing 90 parts of the isocyanate-terminated polyurethane prepolymer A with 4 parts of a mechanical interlocking molecule (the mechanical interlocking molecule is 2-(hydroxymethyl)-12-crown 4-ether and a platinum (II) complex of bipyridine carboxylate, with a mass ratio of 1:1), heating to 120° C. under continuous nitrogen protection for reaction for 40 minutes to obtain a reaction product B.

[0063] c) 50 parts of the isocyanate-terminated polyurethane prepolymer A are mixed with 44 parts of the reaction product B, and 6 parts of ethylene glycol are added. After mixing at 110° C. for 1 hour, the mixture is poured into a mold of a certain shape, and demoulded after cooling at room temperature to obtain a polyurethane sealing material.

[0064] Example 2

[0065] a) 30 parts of polycarbonate polyol were added into a reactor, and water was removed at 120° C. for 2 h under nitrogen protection. Then, 60 parts of triphenylmethane triisocyanate (the molar ratio of -OH in the polyol to -NCO in the isocyanate was 1:2) were added, and the mixture was heated to 70° C. for reaction for 4 h under continuous nitrogen protection to obtain an isocyanate-terminated polyurethane prepolymer A.

[0066] b) Mixing 90 parts of the isocyanate-terminated polyurethane prepolymer A with 5 parts of the mechanical interlocking molecule (the mechanical interlocking molecule is 2-(hydroxymethyl)-12-crown 4-ether and bipyridine carboxylic acid platinum (II) complex, the mass ratio of the two is 1:1), heating to 120° C. under continuous nitrogen protection for reaction for 40 minutes to obtain a reaction product B.

[0067] c) 50 parts of the isocyanate-terminated polyurethane prepolymer A are mixed with 45 parts of the reaction product B, and then 5 parts of resorcinol di(2-hydroxyethyl) ether are added. After mixing at 110° C. for 2 hours, the mixture is poured into a mold of a certain shape, and demolded after cooling at room temperature to obtain a polyurethane sealing material.

[0068] Example 3

[0069] a) 15 parts of polycaprolactone polyol and 15 parts of polycarbonate polyol were added into a reactor, and water was removed at 120° C. for 2 h under nitrogen protection. Then, 30 parts of hexamethylene diisocyanate and 30 parts of triphenylmethane triisocyanate (the molar ratio of -OH in the polyol to -NCO in the isocyanate was 1:X) were added, and the mixture was heated to 70° C. for reaction for 4 h under continuous nitrogen protection to obtain an isocyanate-terminated polyurethane prepolymer A.

[0070] b) Mix 90 parts of the isocyanate-terminated polyurethane prepolymer A with 7 parts of the mechanical interlocking molecule (the mechanical interlocking molecule is 2-(hydroxymethyl)-12-crown 4-ether and bipyridine platinum (II) complex, and the mass ratio of the two is 1:1), heat to 120° C. under continuous nitrogen protection, and react for 40 minutes to obtain a reaction product B.

[0071] c) 50 parts of the isocyanate-terminated polyurethane prepolymer A are mixed with 45 parts of the reaction product B, and then 1.5 parts of ethylene glycol and 1.5 parts of resorcinol di(2-hydroxyethyl) ether are added, mixed at 110° C. for 2 hours, poured into a mold of a certain shape, and demolded after cooling at room temperature to obtain a polyurethane sealing material.

[0072] Comparative Example 1

[0073] The process is carried out according to Example 1, except that no mechanical interlocking molecules are introduced, that is, step b) is not performed; the specific process is as follows:

[0074] S1. Add 30 parts of polycaprolactone polyol into the reactor, remove water at 120°C for 2 hours under nitrogen protection, then add 60 parts of hexamethylene diisocyanate (the molar ratio of -OH in the polyol to -NCO in the isocyanate is 1:2), heat to 70°C under continuous nitrogen protection for 4 hours to obtain terminal isocyanate polyurethane prepolymer A.

[0075] S2. Take 94 parts of isocyanate-terminated polyurethane prepolymer A, add 6 parts of ethylene glycol, mix at 110° C. for 1 hour, pour into a mold of a certain shape, and demould after cooling at room temperature to obtain a polyurethane sealing material.

[0076] Comparative Example 2

[0077] The implementation is carried out according to Example 2, except that no mechanical interlocking molecules are introduced, that is, step b) is not performed; the specific process is as follows:

[0078] S1. Add 30 parts of polycarbonate polyol into the reactor, remove water at 120°C for 2 hours under nitrogen protection, then add 60 parts of triphenylmethane triisocyanate (the molar ratio of -OH in the polyol to -NCO in the isocyanate is 1:2), heat to 70°C under continuous nitrogen protection for reaction for 4 hours, and obtain terminal isocyanate polyurethane prepolymer A.

[0079] S2. Take 95 parts of isocyanate-terminated polyurethane prepolymer A, add 5 parts of resorcinol di(2-hydroxyethyl) ether, mix at 110° C. for 2 hours, pour into a mold of a certain shape, and demould after cooling at room temperature to obtain a polyurethane sealing material.

[0080] Comparative Example 3

[0081] The implementation is carried out according to Example 3, except that no mechanical interlocking molecules are introduced, that is, step b) is not performed; the specific process is as follows:

[0082] S1. Add 15 parts of polycaprolactone polyol and 15 parts of polycarbonate polyol into a reactor, remove water at 120°C for 2 hours under nitrogen protection, then add 30 parts of hexamethylene diisocyanate and 30 parts of triphenylmethane triisocyanate (the molar ratio of -OH in the polyol to -NCO in the isocyanate is 1:2), heat to 70°C under continuous nitrogen protection for reaction for 4 hours, and obtain terminal isocyanate polyurethane prepolymer A.

[0083] S2. Take 95 parts of isocyanate-terminated polyurethane prepolymer A, add 1.5 parts of ethylene glycol and 1.5 parts of resorcinol di(2-hydroxyethyl) ether, mix at 110° C. for 2 hours, pour into a mold of a certain shape, and demold after cooling at room temperature to obtain a polyurethane sealing material.

[0084] Comparative Example 4

[0085] The method is implemented in accordance with Example 1, except that in step b), the platinum (II) bipyridine carboxylate complex in the mechanical interlocking molecule is replaced by 2-(hydroxymethyl)-12-crown 4-ether (i.e., all mechanical interlocking molecules are 2-(hydroxymethyl)-12-crown 4-ether).

[0086] Comparative Example 5

[0087] The method is implemented in accordance with Example 1, except that in step b), 2-(hydroxymethyl)-12-crown 4-ether in the mechanical interlocking molecule is replaced with a platinum (II) bipyridine carboxylate complex (ie, all mechanical interlocking molecules are platinum (II) bipyridine carboxylate complexes).

[0088] Example 4: Product Testing

[0089] The tensile strength, dynamic wear resistance and shape recovery performance of the polyurethane materials obtained in the above embodiments and comparative examples were tested. The results are shown in Table 1.

[0090] The tests are as follows:

[0091] (1) Tensile strength: refer to national standard GB / T528-1998.

[0092] (2) Dynamic wear resistance: refer to national standard GB / T12967.2-2008.

[0093] (3) Shape recovery performance (rebound value): refer to national standard GB / T 1681-2009.

[0094] Table 1: Test results of various embodiments and comparative examples

[0095] Tensile strength, MPa Wear coefficient Rebound value, % Example 1 51 0.85 95 Example 2 63 0.82 98 Example 3 55 0.88 96 Comparative Example 1 40 0.99 90 Comparative Example 2 45 0.97 85 Comparative Example 3 43 1.12 87 Comparative Example 4 44 1.21 88 Comparative Example 5 42 1.12 84

[0096] It can be seen from the test results in Table 1 that the tensile strength of the polyurethane materials obtained in Examples 1-3 of the present invention is above 50MPa, the wear coefficient in the dynamic wear resistance test is below 0.88, and the rebound value in the shape recovery reaches more than 95%, showing excellent toughness, dynamic wear resistance and shape recovery. Compared with Examples 1-3, the various properties of the materials obtained in Comparative Examples 1-3 are significantly worse, proving that the introduction of mechanical interlocking molecules in step b) of the present invention in combination with other materials of the present invention is beneficial to improving the toughness, dynamic wear resistance and shape recovery of the material. Compared with Example 1, the various properties of the materials obtained in Comparative Examples 4-5 are significantly worse, proving that the present invention uses 2-(hydroxymethyl)-12-crown 4-ether to replace the two specific substances of bipyridine carboxylic acid platinum (II) complex as mechanical interlocking molecules, which is beneficial to improving the toughness, dynamic wear resistance and shape recovery of the material.

[0097] Specific examples are used herein to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core ideas, including the best mode, and also enable any technician in the field to practice the present invention, including making and using any device or system, and implementing any combined method. It should be pointed out that for ordinary technicians in this technical field, without departing from the principle of the present invention, the present invention can also be improved and modified, and these improvements and modifications also fall within the scope of protection of the claims of the present invention. The scope of patent protection of the present invention is defined by the claims and may include other embodiments that can be thought of by those skilled in the art. If these other embodiments have structural elements similar to the literal expression of the claims, or if they include equivalent structural elements that are not substantially different from the literal expression of the claims, then these other embodiments should also be included in the scope of the claims.

Claims

1. A method for preparing a polyurethane sealing material, characterized in that: The following steps are involved: a) reacting a polyol with an isocyanate to obtain an isocyanate-terminated polyurethane prepolymer A; b) mixing and reacting the terminal isocyanate polyurethane prepolymer A with the mechanical interlocking molecules to obtain a reaction product B; c) mixing the isocyanate-terminated polyurethane prepolymer A with the reaction product B and a chain extender to obtain a polyurethane sealing material; The mechanical interlocking molecule is a complex of 2-(hydroxymethyl)-12-crown 4-ether and bipyridine carboxylic acid platinum (II); The mass ratio of the 2-(hydroxymethyl)-12-crown 4-ether to the bipyridine carboxylic acid platinum (II) complex is (5-10):1; In step b), the amount of the mechanical interlocking molecules used is 2 wt% to 8 wt% of the total amount of the substances used in step b).

2. The preparation method according to claim 1, characterized in that: In step b), the reaction temperature is 100-130°C.

3. The preparation method according to claim 1, characterized in that: In step c), the chain extender is ethylene glycol and / or resorcinol bis(2-hydroxyethyl) ether.

4. The preparation method according to claim 1, characterized in that: In step c), the mass ratio of the isocyanate-terminated polyurethane prepolymer A to the reaction product B is 1:(0.2-1); The amount of the chain extender used is 2 wt% to 10 wt% of the total amount of the substances used in step c).

5. The preparation method according to claim 1, characterized in that: In step c), the mixing temperature is 100-130°C.

6. The preparation method according to claim 1, characterized in that: In step a): The polyol is at least one of polycarbonate polyol, polycaprolactone polyol, polytetramethylene glycol polyol and polypropylene oxide polyol; The isocyanate is at least one of hexamethylene diisocyanate, naphthalene diisocyanate, diphenylmethane diisocyanate, toluene diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate and triphenylmethane triisocyanate.

7. The preparation method according to claim 1, characterized in that: In step a): The molar ratio of -OH in the polyol to -NCO in the isocyanate is 1:(1.5-3); The reaction temperature is 60-90° C. and the reaction time is 2-6 hours.

8. A polyurethane sealing material obtained by the preparation method according to any one of claims 1 to 7.