High wear-resistant cast polyurethane composite material and preparation method thereof

Abstract

The application relates to the technical field of high polymer materials, in particular to a high-wear-resistance cast polyurethane composite material and a preparation method thereof. The high-wear-resistance cast polyurethane composite material comprises the following components in parts by mass: 80-94 parts of polyurethane prepolymer, 0.85-0.98 parts of a chain extender, 1-5 parts of a filler, 0.05-0.5 parts of a catalyst and 0.1-1 parts of a defoaming agent; the polyurethane prepolymer is prepared by reacting isocyanate and polyhydric alcohol; the isocyanate is diphenylmethane diisocyanate; and the polyhydric alcohol is one or more of polybutylene adipate glycol, polytetrahydrofuran ether glycol and polycaprolactone glycol. In view of the poor wear resistance of the existing cast polyurethane composite material, the high-wear-resistance cast polyurethane composite material prepared by the application can better reduce DIN abrasion while keeping the tensile strength and elongation at break in a high range, so that good balance between wear resistance and mechanical properties is achieved.

Description

Technical Field

[0001] This application relates to the field of polymer materials technology, and more specifically, to a high wear-resistant castable polyurethane composite material and its preparation method. Background Technology

[0002] Polyurethane composites are a class of block polymers formed by the reaction of isocyanates and polyols. Their molecular structures are highly designable, and the ratio of hard to soft segments can be adjusted, thus exhibiting excellent mechanical strength, wear resistance, oil resistance, chemical corrosion resistance, and good processing properties. They are widely used in mining, metallurgy, construction, transportation, petrochemicals, and other fields. With the development of industrial equipment towards larger scale, higher speed, and automation, higher requirements are placed on the wear resistance of materials under harsh working conditions. Especially in applications such as conveying slurries containing hard particles, pump impellers in high-stress erosion environments, high-speed conveyor belts, and rubber rollers subjected to dynamic impacts, the wear rate of the material directly determines the service life and operational safety of the equipment. Therefore, developing polyurethane composites with exceptional wear resistance while also maintaining mechanical strength and toughness has become a research hotspot in this field.

[0003] Cast polyurethane elastomers (CPUs), an important branch of polyurethane materials, are formed by directly casting liquid raw materials into molds. They offer significant advantages such as high dimensional accuracy, the ability to process large, complex-shaped components, and high production efficiency. Compared to thermoplastic polyurethanes, cast products do not require high-temperature, high-pressure molding equipment, have lower internal stress, and superior overall mechanical properties, making them widely used in core industrial components subjected to high wear and impact. However, the service life of existing cast polyurethane materials under high-speed abrasive wear or high-stress erosion environments remains limited, making it difficult to meet increasingly stringent operating conditions.

[0004] Existing techniques that improve material hardness and modulus by increasing prepolymer crosslinking density or hard segment content can improve wear resistance to some extent, but often lead to decreased material flexibility, making the product prone to early cracking under dynamic impact or repeated deformation. On the other hand, introducing functional additives to improve processing performance or reduce internal stress often adversely affects the final mechanical properties of the material. Therefore, how to improve the wear resistance of cast polyurethane composites while maintaining good tensile strength and elongation at break, avoiding material brittleness, and achieving a stable and industrially feasible processing technology has become a pressing technical challenge in this field. Summary of the Invention

[0005] To address the problem of poor wear resistance in existing cast polyurethane composite materials, this application provides a high wear-resistant cast polyurethane composite material and its preparation method.

[0006] In a first aspect, this application provides a high wear-resistant castable polyurethane composite material, which adopts the following technical solution: A high wear-resistant castable polyurethane composite material comprises the following components in parts by weight: 80-94 parts of polyurethane prepolymer, 0.85-0.98 parts of chain extender, 1-5 parts of filler, 0.05-0.5 parts of catalyst, and 0.1-1 parts of defoamer; wherein the polyurethane prepolymer is prepared by reacting isocyanate and polyol; wherein the isocyanate is diphenylmethane diisocyanate; and wherein the polyol is one or more selected from polybutylene adipate diol, polytetrahydrofuran ether diol, and polycaprolactone diol.

[0007] Preferably, the polyol is a combination of polybutylene adipate diol and polytetrahydrofuran ether diol in a mass ratio of (2-4):1.

[0008] The symmetrical rigid benzene ring structure of diphenylmethane diisocyanate ensures that the isocyanate groups at both ends maintain a specific spatial orientation, matching the arrangement direction of the polar ester bonds in the polybutylene adipate diol molecular chain. During the reaction, the resulting urethane bonds are regularly stacked along the molecular chain direction, forming long-range ordered hard segment microdomains. Meanwhile, the ether bonds in polytetrahydrofuran ether diol, due to the high rotational freedom of the carbon-oxygen single bonds, form flexible soft segment microdomains alternating with the hard segments. These hard segment microdomains are formed through the interaction of groups such as the benzene ring and urethane bonds. The dense physical cross-linking points endow the material with compressive strength to resist abrasive cutting. The polybutylene adipate diol segments, due to the high cohesive energy of their ester bonds, act as support and transfer loads around the hard segments, while the polytetrahydrofuran ether diol segments form a highly compliant continuous phase. When the material is stretched, these compliant polyether segments absorb a large amount of deformation energy through the internal rotation of the ether single bonds. The relative slippage between the polyether and polyester segments under stress further dissipates energy, guiding crack passivation, preventing rapid crack propagation, and avoiding… The stress concentration is eliminated at the hard segment interface. Furthermore, the applicant discovered that the polytetrahydrofuran ether diol segments can form hydrogen bonds and other interactions with the filler surface. When external force is applied, the hydrogen bonds preferentially break to absorb impact energy, and can re-bond after the external force is removed, thereby alleviating stress concentration under external force and improving tensile properties. At the same time, the benzene ring of diphenylmethane diisocyanate interacts with the ester bond of polybutylene adipate diol, enabling the rigid polyester support arm to effectively transfer stress to the physical crosslinking points of the hard segment without debonding. Therefore, this polyurethane prepolymer formed by the combination of rigid symmetrical isocyanate, polar polyester diol, and compliant polyether diol not only endows the polyurethane prepolymer with high rigidity and strength through the benzene ring structure of diphenylmethane diisocyanate, which helps to improve the wear resistance of the composite material, but also ensures the strength and modulus required to resist wear through the physical crosslinking network of the hard segment and the rigid support of the polyester segment. Furthermore, the flexible buffer of the polyether segment allows the composite material to maintain good elongation at break and impact toughness while achieving high wear resistance.

[0009] Therefore, if the content of polybutylene adipate diol is too high, there will be too few polyether segments in the system, which will not be able to form continuous and flexible soft segments. This will result in a lack of flexible buffer between the hard segments and the rigid polyester, leading to a decrease in the elongation at break and an increase in brittleness. If the content of polybutylene adipate diol is too low, the physical cross-linking network of the hard segments will lack the rigid support of the polyester, resulting in insufficient matrix strength, weakened resistance to abrasive cutting and wear resistance, and deterioration of the overall mechanical properties of the composite material.

[0010] Preferably, the filler comprises aminated micronized silicon carbide, epoxidized nano-alumina, and polydopamine-coated modified PMMA microspheres in a mass ratio of (2.8-3.2):(0.8-1.2):(1.5-2.0).

[0011] Preferably, the preparation method of polydopamine-coated modified PMMA microspheres includes: adding polymethyl methacrylate microspheres to Tris-HCl buffer, adding dopamine hydrochloride, stirring at room temperature for 16-24 hours, centrifuging, washing, and drying to obtain polydopamine-coated modified PMMA microspheres.

[0012] More preferably, the mass ratio of polymethyl methacrylate microspheres to dopamine hydrochloride is (8-10):1.

[0013] Micron-sized silicon carbide particles have the largest size and highest hardness, directly resisting the cutting action of external hard particles and improving wear resistance. Polydopamine-coated modified PMMA microspheres are distributed around the silicon carbide particles, and their compressive elastic modulus is between that of silicon carbide and polyurethane matrix, acting as an elastic buffer. When silicon carbide transmits stress, the microspheres undergo reversible elastic deformation, converting some mechanical energy into heat energy for dissipation, protecting the silicon carbide particles from being crushed, and also protecting the silicon carbide-matrix interface from instantaneous overload damage. Nano-alumina fills the gaps between the micron-sized fillers, making the internal structure of the composite material more compact, reducing porosity and defects, thereby improving the overall density and impact resistance of the material. At the same time, the uniform dispersion of modified nanoparticles can enhance the local strength of the matrix, helping to resist the cutting action of abrasive particles, and the nanoparticles can also prevent further crack propagation.

[0014] To further optimize wear resistance, the inventors attempted to influence filler distribution through specific surface treatments, resulting in improved performance. Specifically, the interaction between the amino groups on the silicon carbide surface and the hydroxyl groups on the polymethyl methacrylate (PMMA) microspheres causes PMMA microspheres to adsorb around the silicon carbide particles, forming alternating hard and soft particles of rigid and elastic composition. Under stress, these particles can deform as a whole. Simultaneously, the epoxy groups on the nano-alumina surface can bond with the amino groups in the polydopamine coating and on the silicon carbide surface, anchoring the nano-alumina at the interface between silicon carbide and PMMA microspheres, forming a synergistic particle structure. The rigid framework of silicon carbide and the elastic buffer layer of PMMA microspheres are connected by hydrogen bonds to form stress dissipation units. The nano-alumina, through the chemical bonding of epoxy groups and its own nano-size filling effect, creates a continuous three-dimensional reinforcing network in the entire filler system. The rigid nodes in this network are provided by silicon carbide, and the elastic nodes are provided by PMMA. Methyl methacrylate microspheres and nano-alumina nano-nodes are provided. The three form a synergistic particle structure through hydrogen bonds and chemical bonds, which improves both wear resistance and mechanical properties. The filler further interacts with the polyurethane prepolymer and composite chain extender to dynamically connect the entire filler to the soft segments of the polyurethane, thereby forming a filler network and matrix molecular chain interpenetrating structure inside the composite material. When the composite material is subjected to wear and impact, silicon carbide bears the principal stress and transfers the stress to the polymethyl methacrylate microspheres. The microspheres undergo elastic deformation to absorb energy, while the nano-alumina prevents the formation of local cracks and maintains the integrity of the interface. The filler network and the matrix can form reversible hydrogen bonds, which preferentially break to dissipate energy under stress and reform after pressure relief, thereby dynamically alleviating stress concentration. Ultimately, the composite material maintains excellent tensile strength and elongation at break while significantly improving wear resistance.

[0015] Therefore, if the content of aminated micronized silicon carbide is too low, the rigid skeleton of the composite material is insufficient and cannot effectively withstand the cutting of external abrasive particles. The polymethyl methacrylate microspheres and nano-alumina lose their rigid support, and the stress is directly applied to the matrix, resulting in a decrease in wear resistance and mechanical properties. If the content of polydopamine-coated modified polymethyl methacrylate microspheres is too high, the overall hardness of the composite material decreases and the wear resistance decreases.

[0016] Preferably, the chain extender is MOCA (3,3'-dichloro-4,4'-diaminodiphenylmethane) and HQEE (hydroquinone dihydroxyethyl ether) in a mass ratio of (3-4):1.

[0017] The chain extender employs a composite system of MOCA and HQEE. MOCA, an aromatic diamine chain extender, contains two amino groups and a biphenyl structure in its molecule. It reacts with the isocyanate groups in the polyurethane prepolymer. Due to the symmetrical and rigid structure of MOCA, it forms regular and dense hard segment microdomains, endowing the composite material with high strength and wear resistance. HQEE, an aromatic diol chain extender, contains a rigid hydroquinone structure and two hydroxyethyl ether segments in its molecule. It reacts with the isocyanate groups, with its rigid benzene ring embedded in the hard segment microdomains of MOCA, while the hydroxyethyl ether... Chain segments provide local flexibility, enabling the hard segment micro-regions to maintain both high cohesion and a certain degree of stress relaxation. The hard segment micro-regions formed by the chain extender interact with the active groups of the filler through hydrogen bonds, firmly connecting the elastic nodes in the filler network to the matrix. When the composite material is subjected to tension or impact, MOCA provides resistance to deformation, and HQEE provides moderate toughness. This not only firmly fixes the filler network but also allows for localized slippage and energy dissipation as the soft segments deform, thereby significantly improving the elongation at break and impact toughness while maintaining high wear resistance.

[0018] Secondly, this application provides a method for preparing a high wear-resistant castable polyurethane composite material, using the following technical solution: A method for preparing a high wear-resistant castable polyurethane composite material includes the following steps: (1) taking a polyol and vacuum dehydrating it at 110-120℃ for 2-4h, cooling it down and adding diphenylmethane diisocyanate, heating it up to 75-85℃ under nitrogen protection and reacting for 2-3h, taking a sample and titrating the free isocyanate group content to 6.5-7.5%, cooling it down to 50℃ and discharging it; (2) preheating the polyurethane prepolymer to 80-85℃ and vacuum degassing it for 30-45min, adding chain extender, filler, catalyst and defoamer in sequence, mixing them under stirring at 1500-2000r / min for 1-2min, pouring it into a mold preheated to 100-110℃, and after vulcanization, obtaining a high wear-resistant castable polyurethane composite material.

[0019] Preferably, the vulcanization process includes vulcanizing in an oven at 100-110°C for 2-4 hours, followed by vulcanization at 80-100°C for 12-24 hours after demolding.

[0020] In summary, this application has the following beneficial effects: 1. A polyurethane prepolymer was prepared by reacting diphenylmethane diisocyanate with polybutylene adipate diol and polytetrahydrofuran ether diol. Diphenylmethane diisocyanate has a symmetrical structure and highly reactive functional groups, enabling it to form regular and stable molecular chain structures with polyols. The benzene ring structure of diphenylmethane diisocyanate endows the polyurethane prepolymer with high rigidity and strength, contributing to improved wear resistance of the composite material. Blending polybutylene adipate diol with polytetrahydrofuran ether diol introduces compliant polyether segments, lowering the glass transition temperature of the soft segment and enhancing the toughness of the composite material. This allows the composite material to maintain high tensile strength and elongation at break while exhibiting good wear resistance.

[0021] 2. By forming a graded network through aminated micronized silicon carbide, epoxidized nano-alumina, and polydopamine-coated modified PMMA microspheres, stress is transferred and dissipated step by step, avoiding stress concentration and improving overall wear resistance. Detailed Implementation

[0022] The present application will be further described in detail below with reference to the embodiments.

[0023] Some of the raw materials used in the preparation examples and embodiments: polybutylene adipate diol (PBA2000); polytetrahydrofuran ether diol (PTMG2000); polycaprolactone diol (PCL2000); PMMA microspheres (Spheromers® CALamberti); micron-sized silicon carbide (PT-SiC-8um, Shanghai Pantian Powder Materials Co., Ltd.); nano-alumina (20nm, Nanjing Baoket New Materials Co., Ltd.); Tris-HCl buffer 1M (Tris-HCl, pH 8.5, Beyotime Biotechnology Co., Ltd.); dopamine hydrochloride (Beijing Bio-Tech Technology Co., Ltd.); catalyst: dibutyltin dilaurate; defoamer: polyether-modified polysiloxane (TEGO FOAMEX 1488); unless otherwise specified, all raw materials used in the embodiments and comparative examples are commercially available products.

[0024] Preparation Example 1 Preparation of aminated micronized silicon carbide: 10 parts of micronized silicon carbide were added to 0.6 parts of KH550 and 100 parts of ethanol aqueous solution (ethanol to water volume ratio 4:1), the pH was adjusted to 5 with glacial acetic acid, and the reaction was stirred in a water bath at 55℃ for 3 hours. The mixture was separated by filtration, washed three times with ethanol, and dried under vacuum at 80℃ for 8 hours to obtain aminated micronized silicon carbide.

[0025] Preparation Example 2 Preparation of epoxidized nano-alumina: 10 parts of nano-alumina were added to 0.8 parts of KH560 and 80 parts of ethanol aqueous solution (ethanol to water volume ratio 4:1), the pH was adjusted to 5 with glacial acetic acid, and the reaction was stirred in a water bath at 55℃ for 3 hours. After filtration and separation, the nano-alumina was washed three times with ethanol and dried under vacuum at 80℃ for 8 hours to obtain epoxidized nano-alumina.

[0026] Preparation Example 3 Preparation of polydopamine-coated modified PMMA microspheres: Take 50 parts of polymethyl methacrylate microspheres, add them to 800 parts of Tris-HCl buffer, add 5 parts of dopamine hydrochloride, stir at room temperature for 24 h, centrifuge, wash three times with water, wash once with ethanol, and dry under vacuum at 50 °C to obtain polydopamine-coated modified PMMA microspheres.

[0027] Preparation Example 4 Preparation of polydopamine-coated modified PMMA microspheres: 47 parts of polymethyl methacrylate microspheres were added to 800 parts of Tris-HCl buffer, and 8 parts of dopamine hydrochloride were added. The mixture was stirred at room temperature for 24 hours, centrifuged, washed three times with water, washed once with ethanol, and dried under vacuum at 50℃ to obtain polydopamine-coated modified PMMA microspheres.

[0028] Preparation Example 5 Preparation of polydopamine-coated modified PMMA microspheres: 53 parts of polymethyl methacrylate microspheres were added to 800 parts of Tris-HCl buffer, 2 parts of dopamine hydrochloride were added, and the mixture was stirred at room temperature for 24 h. After centrifugation, the microspheres were washed three times with water and once with ethanol. The microspheres were then dried under vacuum at 50 °C to obtain polydopamine-coated modified PMMA microspheres. Example 1

[0029] A method for preparing a high wear-resistant castable polyurethane composite material includes the following steps: (1) Polybutylene adipate diol and polytetrahydrofuran ether diol are added to a reaction vessel at a mass ratio of 4:1. The mixture is dehydrated at 110℃ and -0.095MPa until the water content is less than 0.03%. The temperature is lowered to 50℃ and diphenylmethane diisocyanate is added at a molar ratio of isocyanate group to hydroxyl group of 2:1. The mixture is heated to 75℃ and reacted for 3 hours under nitrogen protection. The free isocyanate group content is measured by titration until it reaches 6.5%. The mixture is then cooled to 50℃ and discharged to obtain a polyurethane prepolymer, which is then sealed and stored. (2) MOCA was heated at 110°C, and HQEE was added at a mass ratio of 4:1 between MOCA and HQEE. After stirring, the mixture was kept warm at 110°C for later use. (3) 90 parts of polyurethane prepolymer were preheated to 80°C and vacuum degassed for 30 min. Then, 0.9 parts of chain extender, 4 parts of filler, 0.3 parts of catalyst, and 1 part of defoamer obtained in (2) were added in sequence. The mixture was stirred at 1500 r / min for 2 min and poured into a mold preheated to 110°C. The mixture was then vulcanized in an oven at 100°C for 4 h. After demolding, it was vulcanized at 80°C for 12 h to obtain a high wear-resistant castable polyurethane composite material. The filler was prepared in a mass ratio of 3.2:1:1.8, namely, aminated micronized silicon carbide prepared in Preparation Example 1, epoxidized nano-alumina prepared in Preparation Example 2, and polydopamine-coated modified PMMA microspheres prepared in Preparation Example 3. Example 2

[0030] The difference between this embodiment and Example 1 is that (1) polybutylene adipate diol and polytetrahydrofuran ether diol are added to the reaction vessel at a mass ratio of 1:1, and dehydrated to a water content of less than 0.03% under the conditions of 110℃ and -0.095MPa. The temperature is lowered to 50℃ and diphenylmethane diisocyanate is added at a molar ratio of 2:1 between isocyanate groups and hydroxyl groups. The temperature is raised to 75℃ and reacted for 3 hours under nitrogen protection. The free isocyanate group content is measured by titration and reduced to 6.5%. The temperature is lowered to 50℃ and the product is discharged to obtain polyurethane prepolymer, which is then sealed and stored. Example 3

[0031] The difference between this embodiment and Example 1 is that (1) polycaprolactone diol and polytetrahydrofuran ether diol are added to the reactor at a mass ratio of 4:1 and dehydrated to a water content of less than 0.03% at 110℃ and -0.095MPa. The temperature is then lowered to 50℃ and diphenylmethane diisocyanate is added at a molar ratio of 2:1 between isocyanate groups and hydroxyl groups. The temperature is then raised to 75℃ and reacted for 3 hours under nitrogen protection. The free isocyanate group content is measured by titration and reduced to 6.5%. The temperature is then lowered to 50℃ and the product is discharged to obtain polyurethane prepolymer, which is then sealed and stored. Example 4

[0032] The difference between this embodiment and Example 1 is only that (1) polybutylene adipate diol is added to the reaction vessel and dehydrated to a water content of less than 0.03% under the conditions of 110℃ and -0.095MPa. The temperature is lowered to 50℃ and diphenylmethane diisocyanate is added in a ratio of 2 of isocyanate group to hydroxyl group. The temperature is raised to 75℃ under nitrogen protection and reacted for 3h. The free isocyanate group content is measured by sampling and titration until it reaches 6.5%. The temperature is lowered to 50℃ and the material is discharged to obtain polyurethane prepolymer, which is then sealed and stored. Example 5

[0033] The only difference between this embodiment and embodiment 1 is that (2) MOCA is heated at 110°C, HQEE is added at a mass ratio of 1:1 between MOCA and HQEE, and after stirring, it is kept warm at 110°C for later use. Example 6

[0034] The only difference between this embodiment and Example 1 is that, in (3), the filler is the aminated micronized silicon carbide prepared in Preparation Example 1, the epoxidized nano-alumina prepared in Preparation Example 2, and the polydopamine-coated modified PMMA microspheres prepared in Preparation Example 4, with a mass ratio of 3.2:1:1.8. Example 7

[0035] The only difference between this embodiment and Example 1 is that, in (3), the filler is the aminated micronized silicon carbide prepared in Preparation Example 1, the epoxidized nano-alumina prepared in Preparation Example 2, and the polydopamine-coated modified PMMA microspheres prepared in Preparation Example 5, with a mass ratio of 3.2:1:1.8. Example 8

[0036] The only difference between this embodiment and Example 1 is that, in (3), the filler is the aminated micronized silicon carbide prepared in Preparation Example 1, the epoxidized nano-alumina prepared in Preparation Example 2, and the polydopamine-coated modified PMMA microspheres prepared in Preparation Example 3, with a mass ratio of 2:2.2:1.8. Example 9

[0037] The only difference between this embodiment and Example 1 is that, in (3), the filler is the aminated micronized silicon carbide prepared in Preparation Example 1, the epoxidized nano-alumina prepared in Preparation Example 2, and the polydopamine-coated modified PMMA microspheres prepared in Preparation Example 3, with a mass ratio of 2.8:0.8:2.4. Example 10

[0038] The only difference between this embodiment and Example 1 is that, in (3), the filler is the aminated micronized silicon carbide, nano-alumina prepared in Preparation Example 1, and the polydopamine-coated modified PMMA microspheres prepared in Preparation Example 3, with a mass ratio of 3.2:1:1.8. Example 11

[0039] The only difference between this embodiment and Example 1 is that, in (3), the filler is the aminated micronized silicon carbide prepared in Preparation Example 1, the epoxidized nano-alumina prepared in Preparation Example 2, and the PMMA microspheres prepared in Preparation Example 2, with a mass ratio of 3.2:1:1.8. Example 12

[0040] The only difference between this embodiment and Example 1 is that, in (3), the filler is the aminated micronized silicon carbide prepared in Preparation Example 1 and the epoxidized nano-alumina prepared in Preparation Example 2, with a mass ratio of 5:1. Example 13

[0041] The only difference between this embodiment and Example 1 is that, in (3), the filler is the aminated micronized silicon carbide prepared in Preparation Example 1 and the polydopamine-coated modified PMMA microspheres prepared in Preparation Example 3, with a mass ratio of 4.2:1.8. Example 14

[0042] The only difference between this embodiment and embodiment 1 is that, in (3), the filler is micron-sized silicon carbide.

[0043] The performance testing of the high wear-resistant castable polyurethane composite materials prepared in the examples and comparative examples was conducted using the following methods: a. Hardness (Shore A); b. Tensile strength and elongation at break: Tested according to standard GB / T 528-2009, using dumbbell-shaped specimens; c. DIN wear: Tested according to GB / T 9867-2008; the test results are shown in Table 1 below: Table 1 Performance Test Results

[0044] As shown in Table 1, the high-wear-resistant castable polyurethane composite material prepared in this application can better reduce DIN wear while maintaining tensile strength and elongation at break within a high range, achieving a good balance between wear resistance and mechanical properties. Compared with Comparative Examples 1-5, the benzene ring structure of diphenylmethane diisocyanate imparts high rigidity and strength to the polyurethane prepolymer, which helps to improve the wear resistance of the composite material. Furthermore, the physical crosslinking network of the hard segments and the rigid support of the polyester segments ensure the strength and modulus required to resist wear, while the flexible buffering of the polyether segments allows the composite material to maintain good elongation at break and impact toughness while achieving high wear resistance.

[0045] Compared with Examples 1 and 6-14, it can be seen that the rigid skeleton of silicon carbide and the elastic buffer layer of polymethyl methacrylate microspheres are connected by hydrogen bonds to form stress dissipation units, while the nano-alumina forms a synergistic wear-resistant reinforcing particle structure through the chemical bonding of epoxy groups and its own nano-size filling effect, so that the composite material maintains excellent tensile strength and elongation at break while significantly improving wear resistance.

[0046] The above are all preferred embodiments of this application and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made to the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A high wear-resistant castable polyurethane composite material, characterized in that: The product comprises the following components in parts by weight: 80-94 parts of polyurethane prepolymer, 0.85-0.98 parts of chain extender, 1-5 parts of filler, 0.05-0.5 parts of catalyst, and 0.1-1 parts of defoamer; wherein the polyurethane prepolymer is prepared by reacting isocyanate and polyol; wherein the isocyanate is diphenylmethane diisocyanate; and wherein the polyol is one or more of polybutylene adipate diol, polytetrahydrofuran ether diol, and polycaprolactone diol.

2. The high wear-resistant castable polyurethane composite material according to claim 1, characterized in that: The polyol is a combination of polybutylene adipate diol and polytetrahydrofuran ether diol in a mass ratio of (2-4):

1.

3. The high wear-resistant castable polyurethane composite material according to claim 1, characterized in that: The filler comprises aminated micronized silicon carbide, epoxidized nano-alumina, and polydopamine-coated modified PMMA microspheres in a mass ratio of (2.8-3.2):(0.8-1.2):(1.5-2.0).

4. The high wear-resistant castable polyurethane composite material according to claim 3, characterized in that: The preparation method of the polydopamine-coated modified PMMA microspheres includes: adding polymethyl methacrylate microspheres to Tris-HCl buffer, adding dopamine hydrochloride, stirring at room temperature for 16-24 hours, centrifuging, washing, and drying to obtain polydopamine-coated modified PMMA microspheres.

5. The high wear-resistant castable polyurethane composite material according to claim 4, characterized in that: The mass ratio of the polymethyl methacrylate microspheres to dopamine hydrochloride is (8-10):

1.

6. The high wear-resistant castable polyurethane composite material according to claim 1, characterized in that: The chain extender is MOCA and HQEE in a mass ratio of (3-4):

1.

7. The method for preparing the high wear-resistant castable polyurethane composite material according to claims 1-6, characterized in that: The process includes the following steps: (1) Take polyol and dehydrate it under vacuum at 110-120℃ for 2-4 hours, then add diphenylmethane diisocyanate at a lower temperature, and react it at 75-85℃ for 2-3 hours under nitrogen protection. Take a sample and titrate the free isocyanate group content to 6.5-7.5%, then cool it down to 50℃ and discharge it; (2) Preheat the polyurethane prepolymer to 80-85℃ and degas it under vacuum for 30-45 minutes, then add chain extender, filler, catalyst and defoamer in sequence and mix them under stirring at 1500-2000r / min for 1-2 minutes. Pour it into a mold preheated to 100-110℃, and after vulcanization, obtain a high wear-resistant castable polyurethane composite material.

8. The method for preparing the high wear-resistant castable polyurethane composite material according to claim 7, characterized in that: The vulcanization process includes vulcanization in an oven at 100-110℃ for 2-4 hours, followed by vulcanization at 80-100℃ for 12-24 hours after demolding.

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