Rubber insulating and sheathing material for wind power

Abstract

The present application relates to the technical field of wind power generation materials, in particular to a rubber insulation material and sheath material for wind power generation. The rubber insulation material and sheath material for wind power generation comprises an insulation inner layer, an interface transition layer and a sheath outer layer. In the rubber insulation material and sheath material for wind power generation, the insulation inner layer is coupled with nanocellulose through a double mechanism of chemical coupling of plant-based diluent and physical adsorption of expanded graphite, so as to reduce the processing viscosity of the epoxy resin system on the basis of maintaining the heat resistance and mechanical strength of the material; the sheath outer layer improves the mechanical properties and salt spray corrosion resistance of the material through chemical anchoring of plant fibers and resin and the barrier effect of nanosheet layers; at the same time, the natural rubber-cellulose nanocrystal composite network of the interface transition layer strengthens the interfacial compatibility of the insulation layer and the sheath layer, avoids the risk of separation between the layers, and thus improves the reliability and service life of the material in the extreme environment of offshore wind power equipment.

Description

Technical Field

[0001] This invention relates to the field of wind power generation materials technology, and more specifically, to a rubber insulation material and sheath material for wind power generation. Background Technology

[0002] In the field of wind power generation, especially in offshore wind power scenarios, equipment needs to withstand extreme environments such as high salt spray, strong ultraviolet radiation, and high humidity and high pressure for extended periods, placing stringent requirements on the comprehensive performance of insulation and sheathing materials. Epoxy resin-based composite materials, due to their excellent electrical insulation, chemical corrosion resistance, and structural strength, have become an ideal choice for protecting offshore wind power cables and precision components. However, their inherent high viscosity leads to problems such as uneven mixing, high extrusion resistance, and low molding efficiency during processing, affecting the molding quality and overall performance of the composite material, and increasing processing difficulty and cost.

[0003] In existing technologies, the high processing viscosity of epoxy resin is mainly addressed through chemical modification, physical compounding, and optimization of traditional processes. Chemical modification, such as introducing low molecular weight resins or reactive diluents, can reduce viscosity but may lead to decreased heat resistance or increased internal stress, affecting long-term performance. Physical compounding relies on the addition of leveling agents and release agents, which can easily cause agent migration and deterioration of interfacial adhesion, potentially accelerating material failure in complex marine environments. Optimization of traditional processes, such as upgrading planetary screw equipment or using vacuum degassing, can improve processing results, but the equipment investment cost is high, the production cycle is long, and high-temperature treatment may cause resin oxidation and yellowing, which not only reduces the insulation performance and appearance quality of the material but may also lead to a decrease in the mechanical properties of the material, thereby reducing the long-term stable operation of offshore wind power equipment.

[0004] Therefore, there is an urgent need for a rubber insulation material and sheathing material for wind power generation. Summary of the Invention

[0005] The purpose of this invention is to provide a rubber insulation material and a sheath material for wind power generation, so as to solve the problems mentioned in the background art.

[0006] To achieve the above objectives, firstly, according to Figure 1 As shown, the present invention provides a rubber insulating material and a sheath material for wind power generation, comprising an inner insulating layer, an interface transition layer, and an outer sheath layer, wherein:

[0007] The insulating inner layer adopts a low-viscosity and high-efficiency insulating layer with a high insulation strength ≥25kV / mm and a mixed viscosity ≤3000mPa·s. The insulating inner layer includes 100-120 parts of epoxy resin (E-51), 15-20 parts of plant-based diluent, 5-8 parts of nanocellulose (CNF), 1-2 parts of natural silane coupling agent and 10-15 parts of expanded graphite (EG).

[0008] The interface transition layer comprises 25-35 parts of natural latex (NR latex), 10-18 parts of cellulose nanocrystal (CNC), 8-12 parts of castor oil-based epoxy acrylate, and 3-5 parts of rosemary acid (RA);

[0009] The interface transition layer further comprises the following preparation steps:

[0010] The natural latex is placed in a constant temperature water bath at 30°C and stirred (rotation speed 300 r / min), and the cellulose nanocrystal (CNC, diameter 50-100 nm), castor oil-based epoxy acrylate, and rosemary acid (RA) are sequentially added and stirred for 2 h; during this period, the surface hydroxyl groups of the cellulose nanocrystal are combined with the amino groups of the latex protein through hydrogen bonding, the epoxy groups of the castor oil-based epoxy acrylate are lightly crosslinked with the residual carboxyl groups of the NR latex, the phenolic hydroxyl groups of the rosemary acid are combined with the latex thiol groups through a Michael addition reaction to form a stable network, and finally a milky white interface transition layer coating liquid with a solid content of 45%-50% and a viscosity of 800-1200 mPa·s is formed, which is uniformly coated on the surface of the insulating inner layer by a roll coating process, with a thickness of 50-80 μm, and after drying at room temperature for 24 h, an interface layer with adhesion and antioxidant properties is formed;

[0011] The sheath outer layer comprises 70-90 parts of epoxy castor oil modified epoxy resin (CO-EP), 20-25 parts of sisal fiber (SF), 12-18 parts of glycerol trioleate (GTO), and 6-10 parts of montmorillonite-sodium alginate intercalation composite;

[0012] The plant-based diluent adopts a turpentine-based epoxy diluent (such as a terpene-based glycidyl ether), has biodegradability (degradation rate ≥ 60%), and undergoes a secondary crosslinking reaction with the epoxy resin through the epoxy groups to form an interpenetrating network structure, avoiding small molecule migration; the natural silane coupling agent adopts γ-aminopropyl triethoxysilane (KH-550), the amino group at one end reacts with the hydroxyl groups of the epoxy resin, and the silicon-oxygen group at the other end condenses with the hydroxyl groups of the nanocellulose to form an organic-inorganic covalent bond bridge, further improving the integrity of the composite material; the expanded graphite has an expansion ratio of 200-300 times and a worm-like porous structure, which reduces the viscosity while improving the thermal conductivity;

[0013] The surface hydroxyl group of the cellulose nanocrystal is combined with the amino group of the natural latex protein through hydrogen bond, and is condensed with the hydroxyl group of the epoxy castor oil modified epoxy resin in the sheath layer, to construct organic-inorganic covalent bridging, enhance the compatibility of the interface layer with the insulating inner layer and the sheath outer layer, the epoxy groups at both ends of the castor oil based epoxy acrylate molecular chain are induced to secondary crosslinking reaction with the epoxy resin in the insulating layer through a curing agent, to form a covalent bond network, the phenolic hydroxyl group in the rosemary acid molecule is subjected to Michael addition reaction with the mercapto group of the natural latex protein, to form a stable crosslinking structure, for enhancing the antioxidant performance of the interface transition layer, and the aromatic ring structure thereof consolidates the network structure of the interface layer through the pi-pi stacking action with the surface hydroxyl group of the cellulose nanocrystal;

[0014] The epoxy castor oil modified epoxy resin is prepared by ring-opening addition reaction of the hydroxyl group of castor oil and the epoxy group of bisphenol A type epoxy resin, the flexible fatty acid chain segment of castor oil is introduced into the molecular chain, the cellulose hydroxyl group of sisal fiber in the sheath outer layer is combined with the ester bond, and the remaining epoxy groups are subjected to crosslinking reaction with the hydroxyl group of glycerol trioleate, to form an interpenetrating network structure of 'rigid epoxy skeleton + flexible fatty acid chain + plant fiber reinforcement'.

[0015] Secondly, the application provides a rubber insulation material for wind power generation, including the following preparation steps of an insulating inner layer:

[0016] S1.1, pour the turpentine based epoxy diluent into a reaction kettle, heat to 60 DEG C and stir at 200 r / min, while adding gamma-aminopropyl triethoxysilane, continuously stirring for 30 min, so that the amino group of the silane coupling agent is subjected to preliminary addition reaction with the epoxy group of the diluent to form a pre-crosslinking intermediate with active siloxyl group, improving the dispersion compatibility of the subsequent nanocellulose;

[0017] S1.2, add nanocellulose (CNF, diameter 20-50 nm) into the reaction kettle, maintain 60 DEG C and increase the stirring speed to 500 r / min, disperse for 1 h; during the period, the surface hydroxyl group of the nanocellulose is subjected to condensation reaction with the siloxyl group of the silane coupling agent to form a covalent bond, to prepare a uniformly dispersed nanocellulose-silane-diluent composite liquid;

[0018] S1.3, add the epoxy resin into a double planetary dynamic mixer, heat to 80 DEG C and vacuumize to-0.09 MPa, add the nanocellulose-silane-diluent composite liquid, stir and mix at 300 r / min for 20-30 min; then add expanded graphite (expansion ratio 200-300 times), continue vacuum mixing for 30 min-40 min, so that the resin and diluent are adsorbed by the worm-like porous structure of the expanded graphite, so that the system mixing viscosity is reduced to ≤3000 mPa·s;

[0019] S1.4, mixing methyltetrahydrophthalic anhydride with accelerator DMP-30 at a mass ratio of 9:1, melting at 60 DEG C and then adding into a mixer, keeping 80 DEG C and -0.09 MPa vacuum condition, stirring at 100 r / min for 15 min-20 min to make the curing agent uniformly dispersed, then maintaining the vacuum state for 30 min to remove bubbles in the system, ensuring no porosity defect after curing, and obtaining an epoxy resin-based insulating material;

[0020] S1.5, coating the epoxy resin-based insulating material on the surface of the conductive core wire by a single screw extruder, setting the temperature: 60 DEG C for feeding section, 80 DEG C for compression section, 100 DEG C for metering section, screw speed 15 r / min, coating thickness 3±0.2 mm; after coating, entering a step curing oven, first curing at 100 DEG C for 2 h, then heating to 130 DEG C for 4 h, detecting the curing degree by differential scanning calorimetry (DSC) to be greater than or equal to 95%, and forming a high insulating inner layer with an interpenetrating network structure.

[0021] In the application, first, a "diluent-silane-nanocellulose" chemical connection system is constructed through pre-crosslinking reaction of a plant-based diluent and a natural silane coupling agent and covalent grafting of nanocellulose; ring-opening addition reaction occurs between the epoxy groups of a turpentine-based epoxy diluent and the amino groups of KH-550 to generate a silicon-oxygen-containing intermediate, and the intermediate is condensed with the hydroxyl groups on the surface of nanocellulose to form an organic-inorganic covalent network, which not only solves the problem of high processing viscosity, but also forms a synergistic structure of "nanometer reinforced skeleton + resin flexible matrix" through the high specific surface area (greater than or equal to 200 m 2 / g) of nanocellulose and the adsorption of expanded graphite; for example, the wormhole pores (pore size 50-100 nm) of expanded graphite can physically adsorb resin molecules to reduce molecular entanglement, and the high thermal conductivity of expanded graphite can improve the thermal conductivity of the insulating layer, effectively improve the heat dissipation efficiency, and delay the thermal aging of the material.

[0022] Thirdly, the application provides a sheath material for wind power generation, which comprises the following steps for preparing a sheath outer layer:

[0023] S2.1, after the sisal fibers are cleaned and impurities and dust are removed, the sisal fibers are soaked in a sodium hydroxide solution with a concentration of 5%-10% for 2 h-3 h to remove some impurities such as waxes and pectins on the surface of the sisal fibers and improve the interfacial bonding force between the fibers and the resin; after the soaking is completed, the sisal fibers are washed to neutral with deionized water, and then dried in an oven at 80 DEG C-100 DEG C to a constant weight (every 2 h, the weight is weighed twice, and if the weight difference is less than or equal to 0.1% for two times in succession, it is considered that the weight is constant), and finally the dried sisal fibers are cut into short fibers with a length of 2 cm-5 cm;

[0024] S2.2, the epoxy castor oil modified epoxy resin (CO-EP) is added to the high-speed mixer, the temperature is raised to 50-60 DEG C, and is stirred at 150-200 r / min for 15-20 min, so that it is fully softened, then the treated sisal fiber (SF) is added, and is continuously stirred for 30-40 min, so that the sisal fiber is uniformly dispersed in the epoxy resin, and the cellulose hydroxyl of the sisal fiber is combined with the hydroxyl of the epoxy castor oil modified epoxy resin through an ester bond during the period, then glycerol trioleate (GTO) and the montmorillonite-sodium alginate intercalation compound are added, the stirring speed is increased to 300-400 r / min, and is stirred for 1-1.5 h, so that the components are fully mixed and uniform, and a mixture material with good fluidity and uniformity is formed;

[0025] S2.3, the mixture material is transferred to the double screw extruder, the temperature of the extruder is set as follows: the feeding section is 60-70 DEG C, the compression section is 80-90 DEG C, the metering section is 100-110 DEG C, and the screw rotation speed is 20-30 r / min for extrusion; the extruded profile is directly connected with the insulating inner layer coated with an interface transition layer, the outer sheath layer is firmly combined with the insulating inner layer through the bonding effect of the interface transition layer, and a whole structure is formed;

[0026]

[0027] In the application, first, the sodium hydroxide solution is used to remove the surface impurities of the sisal fiber and activate the hydroxyl group, so that the hydroxyl group is combined with the hydroxyl of the epoxy castor oil modified epoxy resin through an ester bond to form a chemical anchor, which can not only enhance the interface bonding force between the fiber and the resin, but also can relieve the internal stress of the rigid skeleton by inserting the glycerol trioleate as a flexible plasticizer into the epoxy network, and the montmorillonite-sodium alginate intercalation compound can form a physical barrier by nanosheet layer peeling; for example, the cellulose chain of the sisal fiber is wound with the fatty acid chain segment of the epoxy castor oil modified epoxy resin through intermolecular force to form a "rigid and flexible interlocking" structure, which can effectively improve the impact resistance and salt spray aging resistance of the sheath material.

[0028] Secondly, according to the application, the sheath material has the advantages of high mechanical strength, good flexibility, high impact resistance, high salt spray aging resistance, and the like. Figure 1 As shown in the figure, the wrapping process of the application is: a conductive core wire -> an insulating inner layer -> an interface transition layer -> an outer sheath layer.

[0029] ​Compared with the prior art, the application has the following beneficial effects:

[0030] In the wind power rubber insulation material and sheath material, the insulation inner layer reduces the processing viscosity of the epoxy resin system on the basis of maintaining the heat resistance and mechanical strength of the material through the double mechanisms of chemical coupling of plant-based diluent and nanocellulose and physical adsorption of expanded graphite, solving the contradiction between performance, cost and stability of traditional chemical modification, physical compounding and process optimization; the sheath outer layer introduces a sisal fiber reinforced system and a montmorillonite-sodium alginate nanometer intercalation technology, improving the mechanical properties and salt spray corrosion resistance of the material through chemical anchoring of plant fibers and resin and the barrier effect of nanosheets; at the same time, the natural rubber-cellulose nanocrystal composite network of the interface transition layer enhances the interfacial compatibility of the insulation layer and the sheath layer, avoiding the risk of separation between the layers, thereby improving the reliability and service life of the material in extreme environments of offshore wind power equipment. BRIEF DESCRIPTION OF DRAWINGS

[0031] Figure 1 The wind power rubber insulation material and sheath material of the application is wrapped in the flowchart. DETAILED DESCRIPTION

[0032] The technical solutions in the embodiments of the application will be clearly and completely described below with reference to the drawings in the application. Obviously, the described embodiments are only part of the embodiments of the application, rather than all the embodiments. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative labor fall within the protection scope of the application.

[0033] Embodiment 1

[0034] Formula (mass parts):

[0035] Insulation inner layer: E-51 epoxy resin 100 parts, turpentine-based epoxy diluent 15 parts, nanocellulose (CNF) 5 parts, KH-550 silane coupling agent 1 part, expanded graphite (EG) 10 parts, methyl tetrahydrophthalic anhydride curing agent 80 parts, DMP-30 accelerator 8 parts;

[0036] Interface transition layer: natural rubber latex (NR latex) 25 parts, cellulose nanocrystal (CNC) 10 parts, castor oil-based epoxy acrylate 8 parts, rosemary acid (RA) 3 parts;

[0037] Sheath outer layer: epoxy castor oil modified epoxy resin (CO-EP) 70 parts, sisal fiber (SF) 20 parts, glycerol trioleate (GTO) 12 parts, montmorillonite-sodium alginate intercalation composite 6 parts, 2-ethyl-4-methyl imidazole curing agent 2 parts.

[0038] Preparation steps:

[0039] The preparation steps of the insulating inner layer: pour the turpentine-based epoxy diluent into a reaction kettle, heat to 60°C and stir at 200 r / min, add KH-550 silane coupling agent and stir for 30 min to form a pre-crosslinking intermediate; add nanocellulose (diameter 20-50 nm) and disperse at 500 r / min for 1 h to obtain a composite liquid. Add the epoxy resin into a double planetary mixer, vacuumize to -0.09 MPa at 80°C, add the composite liquid and stir for 30 min, then add expanded graphite and vacuum mix for 40 min to reduce the viscosity to 2800 mPa·s; then add the methyltetrahydrophthalic anhydride and DMP-30 mixture, vacuum stir for 20 min and defoam for 30 min, coat on the core wire through a single screw extruder (temperature 60-100°C, rotation speed 15 r / min), and perform stepwise curing (100°C / 2h→130°C / 4h) to form the insulating layer;

[0040] The preparation steps of the interface transition layer: place the natural latex in a 30°C water bath, add CNC (diameter 50-100 nm), castor oil-based epoxy acrylate and rosemary acid at 300 r / min in sequence, stir for 2 h to form a coating liquid with a solid content of 45%, roll coat on the surface of the insulating layer (thickness 50 μm), and dry at room temperature for 24 h;

[0041] The preparation steps of the sheath outer layer: soak the sisal fibers in a 5% NaOH solution for 2 h, wash and dry, then cut into 2 cm short fibers; stir the epoxy castor oil modified epoxy resin at 50°C to soften, add the sisal fibers and mix for 40 min, then add glycerol trioleate and montmorillonite-sodium alginate intercalation compound and stir at 400 r / min for 1 h; transfer the material into a double screw extruder (temperature 60-110°C, rotation speed 20 r / min) to extrude and coat the interface layer, and perform pre-curing (50°C / 2h) and post-curing (80°C / 6h) to form.

[0042] Example 2

[0043] Formula (mass parts):

[0044] Insulating inner layer: E-51 epoxy resin 110 parts, turpentine-based epoxy diluent 18 parts, nanocellulose (CNF) 6 parts, KH-550 silane coupling agent 1.5 parts, expanded graphite (EG) 13 parts, methyltetrahydrophthalic anhydride curing agent 85 parts, and DMP-30 accelerator 9 parts;

[0045] Interface transition layer: natural latex (NR latex) 30 parts, cellulose nanocrystal (CNC) 15 parts, castor oil-based epoxy acrylate 10 parts, and rosemary acid (RA) 4 parts;

[0046] Sheath outer layer: epoxy castor oil modified epoxy resin (CO-EP) 80 parts, sisal fiber (SF) 23 parts, glycerol trioleate (GTO) 15 parts, montmorillonite-sodium alginate intercalation compound 8 parts, 2-ethyl-4-methyl imidazole curing agent 2.5 parts.

[0047] Preparation steps:

[0048] Preparation steps of the insulating inner layer: warm up the turpentine-based epoxy diluent to 60°C, add the KH-550 silane coupling agent and stir for 35 min to form an intermediate containing active siloxyl groups; add 30 nm diameter nanocellulose and disperse at 550 r / min for 1.5 h to obtain a uniform composite liquid; pour the epoxy resin into a double planetary mixer, add the composite liquid under vacuum at 80°C and stir for 25 min, then add expanded graphite with an expansion ratio of 250 times, and vacuum mix for 35 min until the viscosity drops to 2500 mPa·s; then add the methyltetrahydrophthalic anhydride and DMP-30 mixture in a molten state, vacuum stir for 18 min and defoam for 25 min, and coat on the core wire (rotating speed 18 r / min) through a single screw extruder with a temperature gradient of 65°C for feeding, 85°C for compression, and 105°C for metering, and after curing at 105°C for 2.5 h and then warming up to 135°C for 3.5 h, an insulating layer is formed;

[0049] Preparation steps of the interface transition layer: place the natural latex in a 30°C water bath and stir at 350 r / min, then add the 80 nm diameter cellulose nanocrystals, castor oil-based epoxy acrylate, and rosemary acid in sequence, and continue stirring for 2.5 h until a coating liquid with a solid content of 48% is formed; uniformly coat on the surface of the insulating layer (thickness 70 μm) through a roller coating process, and after drying at room temperature for 20 h, an interface layer is formed;

[0050] Preparation steps of the sheath outer layer: soak the sisal fiber in an 8% sodium hydroxide solution for 2.5 h, wash and dry, then cut into 3.5 cm short fibers; warm up the epoxy castor oil modified epoxy resin to 55°C to soften, add the sisal fiber and stir for 35 min, then add the glycerol trioleate and montmorillonite-sodium alginate intercalation compound and stir at 350 r / min for 1.2 h; transfer the material to a double screw extruder (feeding segment 65°C, compression segment 88°C, metering segment 108°C, rotating speed 25 r / min) to extrude and coat the interface layer, first pre-cure at 55°C for 2.5 h, then warm up to 85°C and cure for 7 h to form a sheath layer.

[0051] Example 3

[0052] Formula (mass parts):

[0053] Insulating inner layer: E-51 epoxy resin 120 parts, turpentine-based epoxy diluent 20 parts, nanocellulose (CNF) 8 parts, KH-550 silane coupling agent 2 parts, expanded graphite (EG) 15 parts, methyl tetrahydrophthalic anhydride curing agent 90 parts, DMP-30 accelerator 10 parts;

[0054] Interface transition layer: natural latex (NR latex) 35 parts, cellulose nanocrystal (CNC) 18 parts, castor oil-based epoxy acrylate 12 parts, rosemary acid (RA) 5 parts;

[0055] Sheath outer layer: epoxy castor oil modified epoxy resin (CO-EP) 90 parts, sisal fiber (SF) 25 parts, glycerol trioleate (GTO) 18 parts, montmorillonite-sodium alginate intercalation complex 10 parts, 2-ethyl-4-methyl imidazole curing agent 3 parts.

[0056] Preparation steps:

[0057] Preparation steps of the insulating inner layer: heat the turpentine-based epoxy diluent to 60°C, add the KH-550 silane coupling agent and stir for 40 min to form a pre-crosslinked intermediate; add nanocellulose with a diameter of 50 nm and disperse at 600 r / min for 2 h to obtain a composite liquid. Pour the epoxy resin into a double-planetary mixer, add the composite liquid under vacuum at 80°C and stir for 30 min, then add expanded graphite with an expansion ratio of 300 times, and vacuum mix for 40 min until the viscosity decreases to 2200 mPa·s; then add the methyl tetrahydrophthalic anhydride and DMP-30 mixture, vacuum stir for 20 min and defoam for 30 min, coat on the core wire (rotating speed 20 r / min) through a single-screw extruder with a temperature gradient of 70°C for feeding, 90°C for compression, and 110°C for metering, and after curing at 110°C for 3 h, heat to 140°C for 4 h to form the insulating layer;

[0058] Preparation steps of the interface transition layer: place the natural latex in a 30°C water bath and stir at 400 r / min, then add cellulose nanocrystals with a diameter of 100 nm, castor oil-based epoxy acrylate, and rosemary acid in sequence, and continue to stir for 3 h until a coating liquid with a solid content of 50% is formed; uniformly coat on the surface of the insulating layer (thickness 80 μm) through a roller coating process, and dry at room temperature for 24 h to form the interface layer;

[0059] Preparation step of the outer layer of the sheath: the sisal fibers were soaked in 10% sodium hydroxide solution for 3 hours, washed and dried, and then cut into 5 cm short fibers; the epoxy castor oil modified epoxy resin was softened at 60°C, and the sisal fibers were added and stirred for 40 minutes, then glyceryl trioleate and montmorillonite-sodium alginate intercalation compound were added, and stirred at 400 r / min for 1.5 hours; the material was transferred into a double screw extruder (feeding section 70°C, compression section 90°C, metering section 110°C, rotation speed 30 r / min) to extrude the interfacial layer, and then pre-cured at 60°C for 3 hours, and then cured at 90°C for 8 hours to form the sheath layer.

[0060] Table 1: Amount of each raw material in examples 1-4

[0061]

[0062] In order to verify that the rubber insulation material and sheath material for wind power generation prepared in the embodiments of the present application have good insulation reliability and composite structure stability, the following test examples are used to illustrate the rubber insulation material and sheath material for wind power generation provided by the embodiments of the present application.

[0063] Test example

[0064] The purpose of this test group is to explore the influence of different component proportions on the rubber insulation material and sheath material for wind power generation, and to detect the insulation performance, mechanical properties, weather resistance and interfacial bonding properties of the rubber insulation material and sheath material for wind power generation.

[0065] Test target: test group A, test group B and test group C respectively use the component proportions of the rubber insulation material and sheath material for wind power generation provided by examples 1-3; the control examples use control group A, control group B, control group C, control group D, control group E and control group F, wherein:

[0066] Control group A

[0067] Formula:

[0068] Insulating inner layer: E-51 epoxy resin 80 parts, low molecular weight E-12 epoxy resin 20 parts, active diluent (styrene-based epoxy ethane) 15 parts, nano-alumina 20 parts, curing agent (methyl tetrahydrophthalic anhydride) 80 parts;

[0069] Outer layer of the sheath: pure E-44 epoxy resin 100 parts, silicon carbide filler 30 parts, leveling agent 1 part, curing agent (isophorone diamine) 15 parts.

[0070] Control group B

[0071] Formula:

[0072] Insulating inner layer: E-51 epoxy resin 100 parts, turpentine-based epoxy diluent 15 parts, leveling agent (polydimethylsiloxane) 2 parts, expanded graphite 10 parts, curing agent 80 parts;

[0073] Sheath outer layer: epoxy resin (E-44) 70 parts, sisal fiber 20 parts, paraffin-based release agent 3 parts, montmorillonite 10 parts, curing agent 15 parts.

[0074] Control group C

[0075] Formulation:

[0076] Insulating inner layer: E-51 epoxy resin 100 parts, turpentine-based epoxy diluent 15 parts, nanocellulose 5 parts, expanded graphite 10 parts, curing agent 80 parts;

[0077] Sheath outer layer: epoxy castor oil modified epoxy resin 70 parts, sisal fiber 20 parts, glycerol trioleate 12 parts, montmorillonite-sodium alginate intercalation composite 6 parts, curing agent 2 parts.

[0078] Control group D

[0079] Formulation:

[0080] Insulating inner layer: E-51 epoxy resin 100 parts, traditional active diluent (acrylate epoxy monomer) 15 parts, nanocellulose 5 parts, expanded graphite 10 parts, curing agent 80 parts;

[0081] Interface transition layer / sheath outer layer: same as Example 1.

[0082] Control group E

[0083] Formulation:

[0084] Insulating inner layer: E-51 epoxy resin 100 parts, turpentine-based epoxy diluent 15 parts, silane coupling agent 1 part, expanded graphite 10 parts, curing agent 80 parts;

[0085] Interface transition layer / sheath outer layer: same as Example 1.

[0086] Control group F

[0087] Formulation: same as Example 1, but the curing process is constant temperature 120℃ curing for 4h.

[0088] Test method: according to the insulating properties, mechanical properties, weather resistance and interface bonding properties of the rubber insulation material and sheath material for wind power generation according to the present application, tests are carried out respectively, and the specific test methods are as follows:

[0089] Test method of insulating properties: according to GB / T1410-2006 "Test method of volume resistivity and surface resistivity of solid insulating material", the insulating inner layer is processed into The disc sample was placed in an environment of 23±2℃ and 50±5% relative humidity, a three-electrode system was used to apply a direct current voltage of 500V, and the insulation resistance value at 1min was measured; the volume resistivity was calculated by the formula: v wherein R is the volume resistance, A is the electrode area, and d is the sample thickness); the dielectric strength was measured according to IEC 60243-1:2013, the sample was immersed in transformer oil, and was raised to breakdown at a rate of 2kV / s, and the ratio of the breakdown voltage to the sample thickness was the dielectric strength (unit: kV / mm);

[0090] Table 2 is the detection index of insulation performance

[0091] Volume resistivity (Ω-cm) Dielectric strength (kV / mm) Test Group A 1.2 x 10 14 ]] 26 Test Group B 1.3 x 10 14 ]]> 27 Test Group C 1.1 x 10 14 ]]> 25 Control Group A 8.0 x 10 14 ]]> 22 Control Group B 9.5 x 10 14 ]]> 23 Control Group C 1.0 x 10 14 ]] 24 Control Group D 7.5 x 10 14 ]] 21 Control Group E 9.0 x 10 14 ]]> 23 Control Group F 1.1 x 10 14 ]]> 25

[0092] The test method of mechanical properties: the tensile property test followed GB / T 528-2009 “Determination of tensile stress-strain properties of vulcanized or thermoplastic rubber”, dumbbell-shaped samples (gauge length 50mm) were prepared, and were stretched at a speed of 500mm / min, and the maximum stress at break (tensile strength, unit: MPa) and the elongation of the gauge length section (elongation at break, %) were recorded; the impact resistance was tested according to GB / T 1843-2008 “Determination of Izod impact strength of plastics”, the outer layer of the sheath was processed into a sample of 80mm×10mm×4mm, and was tested using a 5J pendulum impact energy, and the energy absorbed per unit area at the time of sample failure (impact strength, unit: kJ / m 2 );

[0093] Table 3 is the detection index of mechanical properties

[0094]

[0095]

[0096] The test method of weather resistance: the salt spray aging test was performed according to ISO 9227:2017, the composite sample was placed in a 35℃, 5% NaCl solution spray box for 1000h, the surface rusting condition was observed, and the tensile strength retention rate was tested, and the calculation formula was: The ultraviolet aging test was performed according to GB / T 16422.3-2014, using a UVB-313 light source (irradiance 1.0W / m 2 ), under the cycle condition of 8h of 60℃ ultraviolet irradiation and 4h of 50℃ condensation, the sample was exposed for 500h in total, and the sample color difference (ΔE) and surface resistivity retention rate were measured;

[0097] Table 4 is the detection index of weather resistance

[0098]

[0099] ​Test method of interface bonding performance: interlayer peeling strength adopts modified method of ASTM D3359-2017, three-layer composite sample of 100mm*25mm*(3+0.05)mm is prepared, 90° peeling method is used to test the peeling force between insulation layer and sheath layer (unit: N / mm), peeling speed is 100mm / min, and the average value of 5 tests is taken; interface shear strength is based on short beam shear method of ASTM D2344-2016, the composite sample is processed into 40mm*10mm*5mm, the span is set to 20mm, the loading speed is 1mm / min, and the shear strength is calculated by formula: (F is the failure load, b is the sample width, and h is the sample thickness).

[0100] Table 5 is the interface bonding performance detection index

[0101] Interlaminar peel strength (N / mm) Interfacial shear strength (MPa) Test Group A 8.5 12.0 Test Group B 9.2 13.5 Test Group C 9.8 15.0 Control Group A 3.2 5.5 Control Group B 4.0 6.8 Control Group C 7.0 10.0 Control Group D 6.5 9.2 Control Group E 8.0 11.0 Control Group F 7.5 10.5

[0102] According to Tables 2-5, the summary of the above comparative data is as follows:

[0103] Insulation performance: the volume resistivity of the insulation inner layer of the test groups A-C of the application is all ≥1.1*10 14 Ω·cm, and the dielectric strength is ≥25kV / mm, which is better than that of the control group A (traditional low molecular weight resin + active diluent, dielectric strength 22kV / mm) and the control group D (acrylate diluent, dielectric strength 21kV / mm); the core reason is that the turpentine-based epoxy diluent forms an interpenetrating network through secondary crosslinking, avoiding insulation deterioration caused by small molecule migration; the covalent bonding of nanocellulose and silane coupling agent (the control group E does not introduce nanocellulose, and the dielectric strength is low by 2kV / mm) effectively reduces interface defects, and the physical adsorption of expanded graphite further improves system uniformity, so that the insulation performance is stable at a high level;

[0104] Mechanical performance: the tensile strength (43-48MPa), elongation at break (240%-260%) and impact strength (28-32kJ / m 2 ) of the sheath layer of the test groups are all better than those of the control group A (pure epoxy resin sheath, impact strength 18kJ / m 2 ) and the control group B (containing paraffin release agent, tensile strength 30MPa); the key difference is that the flexible fatty acid segment of the epoxy castor oil modified epoxy resin forms an ester bond with the hydroxyl group of the sisal fiber (the tensile strength of the control group C is low by 5MPa without modified epoxy resin), and an interlocking structure of “rigid epoxy skeleton + flexible segment” is constructed; the nanosheet layer peeling of the montmorillonite-sodium alginate intercalation compound (the impact strength of the control group E is low by 5kJ / m 2 ) forms a physical enhancement barrier, so that the mechanical performance is improved by 40%-70%;

[0105] Weathering performance: the tensile strength retention rate of the test group is ≥92% after 1000h of salt spray aging, and the color difference ΔE is ≤1.2 after 500h of UV aging, which is significantly better than the control group A (salt spray retention rate 75%, color difference 3.5) and the control group D (UV surface resistivity retention rate 80%); the core technical advantage lies in that the rosmarinic acid of the interface transition layer is crosslinked with the natural latex through Michael addition reaction, and the aromatic ring structure provides antioxidant capacity (the control group F does not use rosmarinic acid, and the color difference is high by 0.5); the ion exchange function of the montmorillonite-sodium alginate compound captures chloride ions in seawater (the control group C uses ordinary montmorillonite, and the salt spray retention rate is low by 7%), and the hydrogen bond network of cellulose nanocrystals delays the aging process;

[0106] Interface bonding performance: the interlayer peeling strength (8.5-9.8 N / mm) and the interface shear strength (12.0-15.0 MPa) of the test group are higher than those of the control group A (peeling strength 3.2 N / mm) and the control group F (without step curing, shear strength 10.5 MPa); the key technical breakthrough lies in that the cellulose nanocrystals of the interface transition layer form covalent bridging through hydrogen bonds with the nanocellulose of the insulating layer and the epoxy castor oil hydroxyl of the sheath layer (the control group E does not use the interface layer, and the peeling strength is low by 0.5 N / mm); the step curing process (the control group F constant temperature curing) reduces internal stress through gradient crosslinking, so that the interface layer and the inner and outer layers form chemical fusion bonding, and the interlayer force is increased by 2-3 times;

[0107] In summary, the present application solves the contradiction between processing viscosity, environmental adaptability and interlayer compatibility of traditional epoxy resin-based materials through chemical functionalization of plant-based components (pine oil diluent crosslinking, castor oil modification), cross-scale enhancement of nanomaterials (cellulose nanocrystals / montmorillonite platelets) and multiple bonding design of the interface layer (hydrogen bond-covalent bond-π-π stacking); compared with the control group, while maintaining high insulation performance, the processing viscosity is reduced by 40%-60% (mixed viscosity ≤3000 mPa·s), the salt spray aging life is increased by more than 20%, and the interface bonding strength is increased by 150%-200%, thereby improving the processing efficiency, environmental reliability and service life of the insulation and sheath material for offshore wind power equipment.

[0108] The above shows and describes the basic principles, main features and advantages of the present application. Those skilled in the art should understand that the present application is not limited by the above examples, and the above examples and descriptions in the specification are only preferred examples of the present application and are not intended to limit the present application. Without departing from the spirit and scope of the present application, various changes and improvements can be made to the present application, and these changes and improvements all fall within the scope of the claimed present application. The scope of protection of the present application is defined by the appended claims and their equivalents.

Claims

1. A rubber insulation material and sheath material for wind power generation, characterized in that, It includes an inner insulating layer, an interface transition layer, and an outer sheath layer, wherein: The inner insulating layer comprises epoxy resin, plant-based diluent, nanocellulose, natural silane coupling agent, and expanded graphite; the interface transition layer comprises natural latex, cellulose nanocrystals, castor oil-based epoxy acrylate, and rosmarinic acid; the outer sheath comprises epoxy castor oil-modified epoxy resin, sisal fiber, glyceryl trioleate, and montmorillonite-sodium alginate intercalation composite. The plant-based diluent undergoes a secondary cross-linking reaction with the epoxy resin through epoxy groups to form an interpenetrating network structure; the amino group at one end of the natural silane coupling agent reacts with the hydroxyl group of the epoxy resin, and the siloxy group at the other end condenses with the hydroxyl group of the nanocellulose to form an organic-inorganic covalent bond bridge. The hydroxyl groups on the surface of the cellulose nanocrystals are bonded to the amino groups of natural latex protein through hydrogen bonds, and simultaneously condense with the hydroxyl groups of the epoxy castor oil modified epoxy resin in the sheath layer to construct an organic-inorganic covalent bridge; the epoxy groups at both ends of the castor oil-based epoxy acrylate molecular chain and the epoxy resin of the insulating layer undergo a secondary cross-linking reaction initiated by a curing agent to form a covalent bond network. The epoxy castor oil modified epoxy resin is prepared by ring-opening addition of castor oil and bisphenol A epoxy resin. The molecular chain contains flexible fatty acid segments, which can react with the hydroxyl groups of sisal fiber and the hydroxyl groups of glycerol trioleate to form an interpenetrating network structure. The amounts of the inner insulating layer, the interface transition layer, and the outer sheath layer are as follows: Insulating inner layer: 100-120 parts epoxy resin, 15-20 parts plant-based diluent, 5-8 parts nanocellulose, 1-2 parts natural silane coupling agent, and 10-15 parts expanded graphite. Interface transition layer: 25-35 parts natural latex, 10-18 parts cellulose nanocrystals, 8-12 parts castor oil-based epoxy acrylate, 3-5 parts rosmarinic acid; Outer sheath layer: 70-90 parts of epoxy castor oil modified epoxy resin, 20-25 parts of sisal fiber, 12-18 parts of glyceryl trioleate, and 6-10 parts of montmorillonite-sodium alginate intercalation complex.

2. The rubber insulation material and sheath material for wind power generation according to claim 1, characterized in that, The inner insulating layer is a low-viscosity, high-efficiency insulating layer with a high insulation strength of ≥25kV / mm and a mixed viscosity of ≤3000mPa・s.

3. The rubber insulation material and sheath material for wind power generation according to claim 1, characterized in that, The interface transition layer includes the following preparation steps: Natural latex was placed in a 30°C constant temperature water bath and stirred. Cellulose nanocrystals, castor oil-based epoxy acrylate, and rosmarinic acid were added sequentially and stirred continuously for 2 hours. During this process, the hydroxyl groups on the surface of the cellulose nanocrystals were bonded to the amino groups of the natural latex protein through hydrogen bonds. The epoxy groups of the castor oil-based epoxy acrylate were slightly cross-linked with the residual carboxyl groups of the natural latex. The phenolic hydroxyl groups of rosmarinic acid and the thiol groups of the latex formed a stable network through a Michael addition reaction. Finally, a milky white interfacial transition layer coating liquid with a solid content of 45%-50% and a viscosity of 800 mPa·s-1200 mPa·s was formed. The coating was uniformly applied to the surface of the insulating inner layer by a roller coating process, with a thickness of 50 μm-80 μm. After drying at room temperature for 24 hours, an interfacial layer with both adhesion and oxidation resistance was formed.

4. The rubber insulation material and sheath material for wind power generation according to claim 1, characterized in that, The plant-based diluent is a turpentine-based epoxy diluent, which is biodegradable with a degradation rate of ≥60%; the natural silane coupling agent is γ-aminopropyltriethoxysilane.

5. The rubber insulation material and sheath material for wind power generation according to claim 1, characterized in that, The expanded graphite has an expansion ratio of 200 to 300 times and exhibits a worm-like porous structure.

6. A rubber insulating material for wind power generation obtained using the rubber insulating material and sheath material for wind power generation as described in any one of claims 1-5, characterized in that, The steps include preparing the insulating inner layer: S1.1 Add turpentine-based epoxy diluent to the reactor, heat to 60°C and stir at 200 r / min, while adding γ-aminopropyltriethoxysilane and stirring continuously for 30 min to form a pre-crosslinked intermediate; S1.2 Add nanocellulose to the reactor, maintain at 60℃ and increase the stirring rate to 500 r / min, disperse for 1 h; obtain nanocellulose-silane-diluent composite solution; S1.3 Add epoxy resin to a dual planetary mixer, heat to 80℃ and evacuate to -0.09MPa, add nanocellulose-silane-diluent composite liquid, and stir at 300r / min for 20-30min; then add expanded graphite and continue vacuum mixing for 30min-40min until the system viscosity is reduced to ≤3000mPa・s. S1.4 Mix methyltetrahydrophthalic anhydride and accelerator DMP-30 at a mass ratio of 9:1, heat to 60℃ to melt, and then add to a double planetary mixer. Maintain 80℃ and -0.09MPa vacuum conditions, and stir at 100r / min for 15min-20min to ensure uniform dispersion of the curing agent. The vacuum state was then maintained for 30 minutes to remove air bubbles from the system, resulting in an epoxy resin-based insulating material. S1.

5. Epoxy resin-based insulating material is coated onto the surface of the conductive core wire using a single-screw extruder. After coating, the wire is placed in a stepped curing oven and cured at 100°C for 2 hours, then heated to 130°C for 4 hours. The degree of curing is detected by differential scanning calorimetry as ≥95%, forming an insulating inner layer with an interpenetrating network structure.

7. The rubber insulation material for wind power generation according to claim 6, characterized in that, In S1.5, the single-screw extruder is set to the following temperatures: feeding section 60℃ → compression section 80℃ → metering section 100℃, screw speed 15r / min, and coating thickness 3±0.2mm.

8. A wind power generation sheath material obtained using the rubber insulation material and sheath material for wind power generation as described in any one of claims 1-5, characterized in that, The following steps are included in the preparation of the outer sheath layer: S2.1 After cleaning the sisal fiber and removing impurities and dust, soak it in a 5%-10% sodium hydroxide solution for 2-3 hours. Then rinse the sisal fiber with deionized water until it is neutral. Finally, dry it in an oven at 80℃-100℃ until it reaches constant weight. Cut the sisal fiber into short fibers with a length of 2cm-5cm. S2.2 Add the epoxy castor oil modified epoxy resin to a high-speed mixer, heat to 50℃-60℃, and stir at 150r / min-200r / min for 15min-20min to fully soften it; then add short fibers and continue stirring for 30min-40min to evenly disperse the sisal fibers in the epoxy resin; then add glyceryl trioleate and montmorillonite-sodium alginate intercalation complex, increase the stirring speed to 300r / min-400r / min, and stir for 1h-1.5h to fully mix all components and form a mixture. S2.3 Transfer the mixture to a twin-screw extruder for extrusion; the extruded profile is directly and tightly connected to the insulating inner layer with a pre-coated interface transition layer, forming an integral structure through the bonding effect of the interface transition layer; S2.4 Transfer the outer sheath profile connected to the inner insulating layer to a curing oven for curing and molding. First, maintain the temperature at 40℃-60℃ for 2-3 hours for pre-curing, then gradually increase the temperature to 70℃-90℃ for post-curing for 6-8 hours to fully cure the material. After that, take it out and let it cool naturally to room temperature to obtain the sheath material for wind power generation.

9. The wind power generation sheath material according to claim 8, characterized in that, In S2.3, the twin-screw extruder is set to the following temperatures: 60℃-70℃ in the feeding section, 80℃-90℃ in the compression section, and 100℃-110℃ in the metering section, with a screw speed of 20r / min-30r / min for extrusion.

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