CN116217871A - Preparation method of solvent-free polyurethane with self-healing function and preparation method thereof - Google Patents

Abstract

The invention discloses a solvent-free self-healing function polyurethane preparation method and the preparation method thereof, which is prepared from component A and component B according to the mass ratio of 100: (80-120), wherein component A It is composed of polyol, disulfide, 4,4'-dihydroxydiphenyl sulfone, catalyst, leveling agent, etc., and B component is composed of polyisocyanate and polyol; A and B components are synthesized by two-component casting method Polyurethane resin. The polyurethane synthesized by the invention has the characteristics of green environmental protection and no solvent residue; the polyurethane synthesized by the invention has the function of rapid self-repair at 80°C, and can also repair large-scale damage; the polyurethane synthesized by the invention can be used for many times Repeated use: The solvent-free polyurethane resin prepared by the present invention can be made into polyurethane synthetic leather, polyurethane elastomer, polyurethane adhesive, etc., and has a wide range of applications.

Description

Preparation method of solvent-free polyurethane with self-healing function and preparation method thereof

technical field

The invention relates to the field of polymer material polyurethane, in particular to a preparation method of a solvent-free self-repairing polyurethane and a preparation method thereof.

Background technique

Polyurethane resin is a general term for a class of polymer compounds with carbamate units on the main chain synthesized from isocyanate, polyol and small molecule chain extender. Polyurethane resin can be made into polyurethane plastic, polyurethane fiber, polyurethane rubber and elastomer, polyurethane coating, polyurethane adhesive and polyurethane synthetic leather.

However, polyurethane resin usually involves two common problems during use. One is that the product is prone to microscopic cracks due to scratches and collisions during use, and the microscopic cracks develop into macroscopic cracks, which eventually lead to permanent damage to the material, which not only damages the appearance quality of the product, but also affects the service life of the material; the second is Traditional solvent-based polyurethane tends to release toxic and harmful gases during its preparation and use, causing environmental pollution and even threatening people's health.

In view of the above problem one, self-healing polyurethane is a new direction that can well solve the above problem one. At present, the research hotspot of polyurethane self-healing function is intrinsic self-healing, which realizes self-healing of materials by breaking and reorganizing chemical bonds. Common intrinsic self-healing mechanisms include S-S bond, Se-Se bond, Diels-Alder reaction, phenol-urethane bond, hydrogen bond, etc. However, conventional self-healing polyurethane cannot repair large-scale damage, which limits the scope and application prospects of the material.

In response to the second problem above, most of the current synthesis schemes for self-healing polyurethane still require solvents to participate in the preparation process. However, some self-healing polyurethane resins synthesized by a solvent-free method also have some shortcomings, such as unsatisfactory mechanical properties.

The invention patent with the publication number CN108912371A discloses the preparation of a self-healing polyurethane resin based on a Diels-Alder bond in a solvent-free method to obtain a polyurethane resin with excellent repairing effect. However, it needs to be repaired at a high temperature of 120°C. The repair temperature is too high, and the repair efficiency is low, and it cannot repair large-scale damage, which limits its application range.

The invention patent with the publication number CN106750115A discloses the preparation method of the self-repairing polyurethane hydrogel based on the diselenide bond. , and then soaked in deionized water to obtain. The polyurethane hydrogel can achieve self-healing under visible light. However, it uses organic solvents to synthesize polyurethane, which is easy to cause environmental pollution, and is only used in the field of bioengineering, and cannot be applied in other polyurethane fields.

The invention patent with publication number CN109762459A discloses a preparation method of self-healing polyurethane based on a diselenide bond. The solvent-free polyurethane resin with self-healing function and hydrophobic performance is prepared by adding small molecular diselenide and hydroxyl-terminated fluorine-containing polysiloxane into raw materials. However, the polyurethane synthesized by this scheme has low mechanical properties and slow repair speed, which cannot directly realize large-scale damage repair.

Based on the above existing problems, on the one hand, it is necessary to solve the self-healing problem of polyurethane, on the other hand, it is necessary to solve the pollution problem in the solvent preparation of polyurethane, and the existing technical solutions still need to be solved after solving these two problems To solve the problem of new deficiencies, it is necessary to design a new technical solution for preparing self-healing polyurethane by a solvent-free method, and this solution is used to solve the above-mentioned technical problems and deficiencies.

Contents of the invention

The invention provides a preparation method of a solvent-free self-repairing polyurethane and a preparation method thereof.

The solvent-free polyurethane with high-efficiency and large-damage self-repairing function of the present invention and its preparation method, the synthesized polyurethane resin uses disulfide bonds and phenol-urethane bonds as self-repairing, breaking and recombining chemical bonds, both of which only need to be heated at 80°C It can be triggered. The combination of the two can achieve excellent self-repair effect under high temperature conditions, and can also repair large-scale damage. The required repair conditions are simple and have broad application prospects. At the same time, the polyurethane synthesized by the invention does not need to use a solvent, and also solves the problem of organic pollutant discharge during the production and use of solvent-based polyurethane.

Therefore, in view of the above problems, the present invention uses a solvent-free method to prepare polyurethane resin with self-healing function, which can not only improve its appearance quality and service life, but also meet the "green" environmental protection requirements, and will have broad application prospects.

The technical solution adopted by the present invention to solve its technical problems is:

A solvent-free polyurethane with self-healing function, the polyurethane is prepared by casting method from component A and component B according to the weight ratio of 1:0.8-1.2, wherein:

Component A raw material composition comprises:

Polyol

4,4'-Dihydroxydiphenylsulfone

disulfide

catalyst

leveling agent

Component B raw material composition comprises:

polyisocyanate

Polyol

Preferably, the mass percentage of hydroxyl groups in component A is 8-12%, and the mass percentage of isocyanate groups in component B is 15-25%.

Preferably, the molar ratio of isocyanate groups to hydroxyl groups in component B is 1.0-1.2.

Preferably, in parts by weight,

The raw material composition of component A includes: 60-90 parts of polyol, 30-80 parts of 4,4'-dihydroxydiphenyl sulfone, 30-80 parts of disulfide, 0.1-1 part of catalyst and 0.1-1 part of leveling agent share;

The component B raw material composition includes: 100-250 parts of polyisocyanate and 30-100 parts of polyol.

Preferably, the disulfide molecular chain has a dynamic disulfide bond.

Preferably, the disulfide is bis(4-hydroxyphenyl) disulfide or bis(2-hydroxyethyl) disulfide.

Bis(4-hydroxyphenyl) disulfide structural formula is as follows:

The structural formula of bis(2-hydroxyethyl) disulfide is as follows:

Preferably, the structural formula of the 4,4'-dihydroxydiphenyl sulfone is as follows:

Preferably, the polyisocyanate is one or more of isophorone diisocyanate, toluene diisocyanate, hexamethylene diisocyanate, diphenylmethane diisocyanate;

The polyol is one or more of polytetrahydrofuran ether diol, polyglycolide diol, polypropylene glycol, polycarbonate diol, polyethylene adipate diol, and the relative molecular mass of the polyol is 500~4000;

The catalyst is dibutyltin dilaurate, stannous octoate or 1,4-diazidebicyclo[2.2.2]octane;

The leveling agent is BYK-UV3510.

A kind of preparation method of above-mentioned polyurethane, concrete steps are:

(1) Preparation of Component A: According to parts by weight, 60-90 parts of polyol, 30-80 parts of disulfide, 30-80 parts of 4,4'-dihydroxydiphenylsulfone, 0.1-1 parts of catalyst 1 part and 0.1 to 1 part of leveling agent are mixed and reacted with stirring to obtain a polymer containing terminal hydroxyl groups, that is, component A;

(2) Preparation of component B: According to parts by weight, mix and stir 100-250 parts of polyisocyanate and 30-100 parts of polyol under nitrogen atmosphere for 2-4 hours to obtain polyurethane prepolymer, which is the component B;

(3) Add the prepared component A and component B into the reaction kettle according to the weight ratio of 1:0.8~1.2 (more preferably 1:1~1.1), stir and mix at a high speed of 500~2000r/min for 1~10min, Then aging at a temperature of 100° C. to 120° C. for 0.5 to 2 hours to obtain a solvent-free polyurethane with self-healing function.

The present invention uses polyisocyanates, polyols, disulfides, 4,4'-dihydroxydiphenyl sulfone, etc. as raw materials, and uses a two-component method to first synthesize material A and material B, and prepares a material that can be realized at 80 ° C. Self-healing, solvent-free polyurethane resin for large-scale damage repair. In addition, the synthesis method of the present invention does not need to use a solvent, and the polyurethane resin with excellent performance and self-healing can be prepared by directly reacting the raw materials.

Disulfide is a small molecular diol with a disulfide bond in one molecular chain, which can trigger a reversible reaction under high temperature conditions and achieve excellent self-healing effect.

The phenol-urethane bond synthesized by 4,4'-dihydroxydiphenyl sulfone and isocyanate can dissociate under high temperature conditions, realize dynamic reorganization, and achieve excellent self-healing effect.

The polyurethane synthesized by the invention has high repair efficiency, can realize large-scale damage repair, has simple repair conditions, and the repaired material can still maintain excellent mechanical properties. Under the condition of 80 ℃, after 10 minutes of repair, the repair effect of tensile stress and elongation at break can reach 90%; and it can repair defects with a diameter of 1mm and a depth of 1mm, and realize large-scale damage repair.

The beneficial effects of the present invention are:

The polyurethane synthesized by disulfide and 4,4'-dihydroxydiphenyl sulfone in the present invention can realize rapid damage repair under the condition of high temperature of 80° C., and the product can be repeatedly used.

The invention can repair large-scale damage under the condition of 80° C. through the synergistic triggering action of the dynamic disulfide bond and the dynamic phenol-urethane bond, and realize the effect of prolonging the service life of the product.

The self-healing polyurethane of the present invention is synthesized by a solvent-free two-component method, does not release toxic and harmful gases, is healthy and environmentally friendly, and the synthesized polyurethane has excellent mechanical properties and high production efficiency, and solves the problems of solvent-based polyurethane polluting the environment and wasting resources.

Description of drawings

Figure 1 is a microscopic photo of the fracture repair wound;

Figure 2 shows the stress-strain curves of the samples before and after repair.

Detailed ways

A representative embodiment based on the drawings shown will now be further refined. It should be understood that the following description is not intended to limit the embodiments to one preferred embodiment. On the contrary, it is intended to cover alternatives, modifications and equivalents, which may be included within the spirit and scope of the described embodiments as defined by the appended claims.

The present invention provides a solvent-free polyurethane with self-healing function. This polyurethane is poured by component A and component B according to the weight ratio of 100: (80-120), that is, the weight ratio of 1:0.8-1.2 prepared by method.

Among them, in parts by weight,

The raw material composition of component A includes: 60-90 parts of polyol, 30-80 parts of disulfide, 30-80 parts of 4,4'-dihydroxydiphenyl sulfone, 0.1-1 part of catalyst and 0.1-1 part of leveling agent share;

The component B raw material composition includes: 100-250 parts of polyisocyanate and 30-100 parts of polyol.

The mass percentage of hydroxyl groups in component A is 8-12%, the mass percentage of isocyanate groups in component B is 15-25%, and the molar ratio of isocyanate groups to hydroxyl groups is 1.0-1.2.

Regarding the components used in component A and component B, wherein:

The polyisocyanate is one or more of isophorone diisocyanate, toluene diisocyanate, hexamethylene diisocyanate, and diphenylmethane diisocyanate;

The polyol is one or more of polytetrahydrofuran ether diol, polyglycolide diol, polypropylene glycol, polycarbonate diol, polyethylene adipate diol, and the relative molecular mass of the polyol is 500-4000; the catalyst is dibutyltin dilaurate, stannous octoate or 1,4-bicyclo[2.2.2]octane diazide; the leveling agent is BYK-UV3510.

There are dynamic disulfide bonds in the disulfide molecular chain, and the disulfide is bis(4-hydroxyphenyl) disulfide or bis(2-hydroxyethyl) disulfide.

Bis(4-hydroxyphenyl) disulfide structural formula is as follows:

The structural formula of bis(2-hydroxyethyl) disulfide is as follows:

The structural formula of 4,4'-dihydroxydiphenylsulfone is as follows:

The specific steps of the pouring method used are as follows:

(1) Preparation of component A: in parts by weight, 60-90 parts of polyol, 30-80 parts of disulfide, 30-80 parts of 4,4'-dihydroxydiphenylsulfone, and 0.1-1 part of catalyst Mix with 0.1 to 1 part of leveling agent and stir to react to obtain a polymer containing terminal hydroxyl groups, that is, component A;

(2) Preparation of component B: According to parts by weight, mix and stir 100-250 parts of polyisocyanate and 30-100 parts of polyol under nitrogen atmosphere for 2-4 hours to obtain polyurethane prepolymer, which is the component B;

(3) Add the prepared component A and component B into the reaction kettle according to the weight ratio of 1:0.8-1.2, stir and mix, and then ripen at 105°C-125°C to obtain a solvent-free polyurethane with self-healing function.

Example 1:

A solvent-free polyurethane with self-healing function, the preparation steps are as follows:

Prepare the raw materials according to the following ratio,

Component A raw materials: 85 parts of polypropylene glycol (molecular weight 1500, Zhangjiagang Feihang Technology Co., Ltd., FH-3170), 30 parts of bis(2-hydroxyethyl) disulfide, 4,4'-dihydroxydiphenyl sulfone 40 parts, 1 part of dibutyltin dilaurate, 1 part of leveling agent BYK-UV35101; the mass percentage of hydroxyl groups in component A is 11%.

Component B raw materials: 100 parts of isophorone diisocyanate, 75 parts of polypropylene glycol (molecular weight 1500, Zhangjiagang Feihang Technology Co., Ltd., FH-3170). The mass percentage of isocyanate groups in component B is 18%. The molar ratio of isocyanate groups to hydroxyl groups in component B was 1.0.

Then, using the above method, mix 100 parts of isophorone diisocyanate with 75 parts of polypropylene glycol, and stir at a high speed of 1500 rpm for 10 minutes to prepare material B. Gradually add 30 parts of bis(2-hydroxyethyl) disulfide, 40 parts of 4,4'-dihydroxydiphenyl sulfone, 1 part of dibutyltin dilaurate, and 1 part of leveling agent BYK-UV3510 to 85 parts of polypropylene glycol , to obtain Component A.

Then, add material B to material A, react for 10 minutes under high-speed stirring at 1500 rpm, put it into a mold, scrape and form a film, put it in a 100°C oven for 1 hour, and solidify to form a film to obtain a solvent-free type Self-healing polyurethane.

Example 2:

A solvent-free polyurethane with self-healing function, the preparation steps are as follows:

Prepare the raw materials according to the following ratio,

Component A raw materials: polytetrahydrofuran ether diol (molecular weight 2000, Zhangjiagang Feihang Technology Co., Ltd., FH-6330) 45 parts, polyglycolide diol 40 parts, bis(4-hydroxyphenyl) disulfide 40 parts 30 parts of 4,4'-dihydroxydiphenyl sulfone, 1 part of dibutyltin dilaurate, 100.1 parts of leveling agent BYK-UV35; the mass percentage of hydroxyl groups in component A is 12%.

Component B raw materials: 78 parts of toluene diisocyanate, 40 parts of polytetrahydrofuran ether diol, 35 parts of polyglycolide diol (molecular weight 2000, Zhejiang Hexin Technology Co., Ltd., FH-2130); The mass percentage is 20%. The molar ratio of isocyanate groups to hydroxyl groups in component B was 1.1.

Mix 78 parts of toluene diisocyanate with 40 parts of polytetrahydrofuran ether diol and 35 parts of polyglycolide diol, and stir at a high speed of 1500 rpm for 10 minutes to prepare material B. Gradually add 40 parts of bis(4-hydroxyphenyl) disulfide, 30 parts of 4,4'-dihydroxydiphenyl sulfone, 1 part of Dibutyltin laurate, 0.1 part of leveling agent, prepared A material.

Add material B to material A, react under high-speed 1500 rpm stirring for 8 minutes, put it into the mold, scrape to form a film, put it in a 100°C oven for 2 hours, and solidify to form a film to obtain a solvent-free self-healing Polyurethane.

Example 3:

A solvent-free polyurethane with self-healing function, the preparation steps are as follows:

Prepare the raw materials according to the following ratio,

Component A raw materials: 45 parts of polytetrahydrofuran ether diol (molecular weight 2000, Zhangjiagang Feihang Technology Co., Ltd., FH-6330), 40 parts of polypropylene glycol, 45 parts of bis(4-hydroxyphenyl) disulfide, 4, 65 parts of 4'-dihydroxydiphenyl sulfone, 0.1 part of dibutyltin dilaurate, 100.1 parts of leveling agent BYK-UV35; the mass percentage of hydroxyl groups in component A is 12%.

Component B raw materials: 100 parts of isophorone diisocyanate, 40 parts of polytetrahydrofuran ether glycol, 35 parts of polypropylene glycol (molecular weight 1500, Zhangjiagang Feihang Technology Co., Ltd., FH-3170); The mass percentage is 20%. The molar ratio of isocyanate groups to hydroxyl groups in component B was 1.1.

Then, mix 100 parts of isophorone diisocyanate with 40 parts of polytetrahydrofuran ether glycol and 35 parts of polypropylene glycol, and stir at a high speed of 1500 rpm for 10 minutes to prepare material B. Gradually add 45 parts of bis(4-hydroxyphenyl) disulfide, 65 parts of 4,4'-dihydroxydiphenyl sulfone, and 0.1 part of dibutyltin dilaurate to 45 parts of polytetrahydrofuran ether glycol and 40 parts of polypropylene glycol , 0.1 part of leveling agent BYK-UV3510 to prepare material A.

Add material B to material A, react under high-speed stirring at 1500 rpm for 5 minutes, put it into the mold, scrape and form a film, put it in an oven at 100°C for 1 hour, and solidify to form a film to obtain a solvent-free self-healing Polyurethane.

Example 4:

A solvent-free polyurethane with self-healing function, the preparation steps are as follows:

Prepare the raw materials according to the following ratio,

Component A raw materials: 85 parts of polypropylene glycol (molecular weight 1500, Zhangjiagang Feihang Technology Co., Ltd., FH-3170), 45 parts of bis(2-hydroxyethyl) disulfide, 4,4'-dihydroxydiphenyl sulfone 65 parts, 0.1 part of dibutyltin dilaurate, 0.1 part of leveling agent BYK-UV35100; the mass percentage of hydroxyl groups in component A is 12%.

Component B raw materials: 78 parts of toluene diisocyanate, 75 parts of polypropylene glycol (molecular weight 1500, Zhangjiagang Feihang Technology Co., Ltd., FH-3170); the mass percentage of isocyanate groups in component B is 18%. The molar ratio of isocyanate groups to hydroxyl groups in component B was 1.1.

Mix 78 parts of toluene diisocyanate with 75 parts of polypropylene glycol, and stir at a high speed of 1500 rpm for 8 minutes to prepare material B. Gradually add 45 parts of bis(2-hydroxyethyl) disulfide, 65 parts of 4,4'-dihydroxydiphenyl sulfone, 0.1 part of dibutyltin dilaurate, and 0.1 part of leveling agent to 85 parts of polypropylene glycol to prepare Get material A.

Add material B to material A, react for 4 minutes under high-speed stirring at 1500 rpm, put it into a mold, scrape it into a film, put it in a 100°C oven for 1.5 hours, and solidify it into a film to obtain a solvent-free self- Repair polyurethane.

Example 5:

A solvent-free polyurethane with self-healing function, the preparation steps are as follows:

Prepare the raw materials according to the following ratio,

Component A raw materials: 85 parts of polytetrahydrofuran ether diol (molecular weight 1000, Zhejiang Hexin Technology Co., Ltd., FH-4210), 50 parts of bis(2-hydroxyethyl) disulfide, 4,4'-dihydroxy disulfide 60 parts of phenylsulfone, 0.1 part of dibutyltin dilaurate, 100.1 parts of leveling agent BYK-UV35; the mass percentage of hydroxyl in component A is 10%.

Component B raw materials: 100 parts of isophorone diisocyanate, 75 parts of polytetrahydrofuran ether diol (molecular weight 2000, Zhejiang Hexin Technology Co., Ltd., FH-8450); the mass percentage of isocyanate groups in component B is 23%. The molar ratio of isocyanate groups to hydroxyl groups in component B was 1.05.

Mix 100 parts of isophorone diisocyanate and 75 parts of polytetrahydrofuran ether glycol, and stir at a high speed of 1500 rpm for 10 minutes to prepare material B. Gradually add 50 parts of bis(2-hydroxyethyl) disulfide, 60 parts of 4,4'-dihydroxydiphenyl sulfone, 0.1 part of dibutyltin dilaurate, 0.1 part of leveling to 85 parts of polytetrahydrofuran ether glycol Agent BYK-UV3510 was used to prepare material A.

Add material B to material A, react under high-speed stirring at 1500 rpm for 5 minutes, put it into the mold, scrape and form a film, put it in an oven at 100°C for 1 hour, and solidify to form a film to obtain a solvent-free self-healing Polyurethane.

According to the test standard ISO 3376:2011, performance tests were performed on the self-healing polyurethane materials prepared in the above examples, and the results are shown in Table 1.

Table 1:

Various performance data tested according to the national standard can be obtained from Table 1.

The test performance of various self-healing polyurethanes in the market is shown in Table 2 (source of data).

Table 2: Test properties of self-healing polyurethane

application principle Diels-Alder bond ^[1] Disulfide bond ^[2] hydrogen bond ^[3] Diselenium bond ^[4] Preparation conditions Solvent-based polyurethane Solvent-based polyurethane Solvent Free Polyurethane Waterborne Polyurethane Tensile Strength 1.62MPa 0.85MPa 10kPa 16.31 MPa Young's modulus —— —— 1.31MPa —— repair condition 110℃, 10h UV light, 24h room temperature 6h Light 2h Repair efficiency 88.15% 97% 87% 80.5%

[1] Li M, Ding H, Yang X, et al. Preparation and properties of self-healing polyurethane elastomer derived from tung-oil-based polyphenol [J]. ACSomega, 2019, 5(1): 529-536.

[2]Rekondo A, Martin R, de Luzuriaga A R, et al.Catalyst-free room-temperature self-healing elastomers based on aromatic disulfide metathesis[J].Materials Horizons,2014,1(2):237-240.

[3] Yao Y, Xu Z, Liu B, et al. Multiple H-Bonding Chain Extender-Based Ultrastiff Thermoplastic Polyurethanes with Autonomous Self-Healability, Solvent-Free Adhesiveness, and AIE Fluorescence [J]. Advanced Functional Materials, 2021, 31( 4):2006944.

[4] Fan W, Jin Y, Shi L. Mechanically robust and tough waterborne polyurethane films based on diselenide bonds and dual H-bonding interactions with fast visible-light-triggered room-temperature self-healability [J]. Polymer Chemistry, 2020, 11 (34):5463-5474.

By comparing the performance of the self-healing polyurethane prepared by the present invention with the current self-healing polyurethane prepared by Diels-Alder bond, disulfide bond, hydrogen bond and other principles, it can be known that the polyurethane synthesized by the present invention has high repair efficiency, simple repair conditions, and The material still maintains excellent mechanical properties. At 80°C for 30 minutes, the repair effect of tensile stress and elongation at break can reach 90%.

As shown in Figure 1, it is a microscope photo of the fracture repair wound, the samples on both sides of the fracture are healed together, the scale bar is 10 μm, and the wound is completely connected.

As shown in Figure 2, it is the stress-strain curve of the sample before and after repair. The original tensile strength is 16.59MPa, and the tensile strength of the fracture repaired sample is 15.05MPa. The performance after repair is excellent.

From a comprehensive evaluation point of view, the self-healing polyurethane obtained by the technical solution provided by the present invention has more excellent performance.

The above embodiments are used to illustrate the present invention, rather than to limit the present invention. Within the spirit of the present invention and the protection scope of the claims, any modification and change of the present invention all fall into the protection scope of the present invention.

Claims (10)

1. A solvent-free polyurethane with self-repairing function is characterized in that: the mass ratio of the composition A to the composition B is 1:0.8 to 1.2, wherein: composition a comprises a polyol, a disulfide, 4' -dihydroxydiphenyl sulfone, a catalyst and a leveling agent; composition B includes a polyisocyanate and a polyol.

2. The solvent-free self-healing polyurethane of claim 1, wherein: the mass ratio of hydroxyl groups in the composition A is 8-12%, and the mass ratio of isocyanate groups in the composition B is 15-25%.

3. The solvent-free self-healing functional polyurethane of claim 1, wherein: the molar ratio of isocyanate groups to hydroxyl groups in the composition B is 1.0-1.2.

4. The solvent-free self-healing functional polyurethane of claim 1, wherein: the composition A comprises the following components in parts by weight:

60-90 parts of polyol;

30-80 parts of disulfide;

30-80 parts of 4,4' -dihydroxydiphenyl sulfone;

0.1-1 part of catalyst;

0.1 to 1 part of leveling agent.

5. The solvent-free self-healing functional polyurethane of claim 1, wherein: the composition B comprises the following components in parts by weight:

100-250 parts of isocyanate;

30-100 parts of polyol.

6. The solvent-free self-healing functional polyurethane according to claim 1 or 4, wherein: the disulfide is one or two of bis (4-hydroxyphenyl) disulfide and bis (2-hydroxyethyl) disulfide.

7. The solvent-free self-healing functional polyurethane of claim 6, wherein: the bis (4-hydroxyphenyl) disulfide and the bis (2-hydroxyethyl) disulfide have the following structures:

bis (4-hydroxyphenyl) disulfide;

bis (2-hydroxyethyl) disulfide.

8. The solvent-free self-healing functional polyurethane according to claim 1 or 4, wherein: the 4,4' -dihydroxydiphenyl sulfone has the following structure:

9. the solvent-free self-healing functional polyurethane of claim 1, wherein:

the polyisocyanate is one or more of isophorone diisocyanate, toluene diisocyanate, hexamethylene diisocyanate and diphenylmethane diisocyanate;

the polyalcohol is one or more of polytetrahydrofuran ether glycol, polyethylene lactone glycol, polypropylene glycol, polycarbonate glycol and polyethylene adipate glycol, and the relative molecular weight is 1000-2000;

the catalyst is dibutyl tin dilaurate, stannous octoate or 1, 4-diazabicyclo [2.2.2] octane;

the leveling agent is BYK-UV3510.

10. The method for producing a solvent-free self-repairing polyurethane according to any one of claims 1 to 9, comprising the steps of:

(1) Preparation of composition A: according to the weight portions, mixing and stirring polyol, disulfide, 4' -dihydroxydiphenyl sulfone, a catalyst and a leveling agent for reaction to obtain a hydroxyl-terminated polymer, namely a composition A;

(2) Preparation of composition B: according to the parts by weight, mixing and stirring polyisocyanate and polyol under the nitrogen atmosphere for 2-4 hours to obtain polyurethane prepolymer, namely the composition B;

(3) Adding the prepared component A and component B into a reaction kettle, stirring and mixing at a high speed of 500-2000 r/min for 1-10 min, and curing at 100-120 ℃ for 0.5-2 h to obtain the solvent-free self-repairing polyurethane.

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