Seabed environment-friendly waterproof insulating material and preparation method thereof

Abstract

The invention relates to the technical field of polymer composite materials, and particularly discloses a seabed environment-friendly waterproof insulating material and a preparation method thereof. The seabed environment-friendly waterproof insulating material is prepared from the following raw materials in parts by mass: 100 parts of ethylene propylene diene monomer, 15-25 parts of thermoplastic vulcanized rubber, 5-8 parts of epoxidized natural rubber, 12-15 parts of modified nano silicon dioxide, 25-35 parts of modified wollastonite, 3-5 parts of a dispersing agent, 1-2 parts of an antioxidant, 2.5-4 parts of a vulcanizing agent, 1-1.2 parts of an activating agent, 0.2-0.4 part of an accelerant and 0.5-1 part of triethanolamine. The surface of the modified nano silicon dioxide is grafted with acrylic acid amino ester and acrylic acid fluorine ester; the surface of the modified wollastonite is grafted with vinyl-terminated polybutadiene. The seabed environment-friendly waterproof insulating material prepared by the invention has excellent waterproof performance, salt spray resistance and mechanical property.

Description

Technical Field

[0001] This application relates to the technical field of polymer composite materials, and more specifically, it relates to an environment-friendly waterproof and insulating material for the seabed and a preparation method thereof. Background Art

[0002] Waterproof and insulating materials are indispensable functional materials in the power transmission and distribution system. Their core value lies in achieving both water molecule barrier and current conduction inhibition through physical barrier effects. In the field of cable engineering, such materials need to meet the requirements of complex environmental adaptability. Especially in subsea power transmission, underground laying, and high-humidity industrial scenarios, their performance directly determines the full-life-cycle reliability of the electrical system.

[0003] Cross-linked polyethylene (XLPE), as a representative of thermosetting insulating materials, although having excellent electrical properties and mechanical strength, has certain limitations in waterproof performance. The polar groups in its molecular structure may lead to the formation of water trees in the long-term humid and hot environment, thereby causing a decline in insulation performance. In contrast, ethylene-propylene rubber (EPR) shows significant advantages in waterproof performance. Its non-polar molecular structure endows the material with natural hydrophobicity, which can effectively block the penetration of water molecules. At the same time, ethylene-propylene rubber has an extremely low water absorption rate, and can maintain the stability of electrical and mechanical properties even under long-term immersion conditions. This excellent waterproof performance makes ethylene-propylene rubber have irreplaceable advantages in application scenarios with high waterproof requirements, such as subsea cables and underground cables.

[0004] The patent application document with the publication number CN119081300A discloses a modified ethylene-propylene-diene monomer rubber material with high resilience and low compression deformation resistant to seawater erosion. The modified ethylene-propylene-diene monomer rubber material includes the following components: ethylene-propylene-diene monomer rubber, polyolefin elastomer, filler, processing aid, tackifying resin, and anti-aging agent, and optionally at least one of a softening and dispersing agent, vulcanizing agent, accelerator, and scorch retarder.

[0005] In this solution, ethylene-propylene-diene monomer rubber is modified by materials such as polyolefin elastomer. However, the polyolefin elastomer does not contain polar groups or cross-linking active sites and is only combined with ethylene-propylene-diene monomer rubber through physical entanglement, resulting in low interfacial bonding strength. Under long-term stress, phase separation or molecular chain slippage is likely to occur, leading to a decrease in tensile strength; the filler is only combined with the matrix through van der Waals forces and is likely to fall off to form micropores under high-pressure environments, becoming the penetration path of seawater. Summary of the Invention

[0006] In order to improve the tensile strength and waterproof performance of the insulating material, this application provides an environment-friendly waterproof and insulating material for the seabed and a preparation method thereof.

[0007] In the first aspect, this application provides an environment-friendly waterproof and insulating material for the seabed, adopting the following technical scheme: An environmentally friendly waterproof insulating material for use in the seabed is prepared from raw materials in the following parts by mass: 100 parts of ethylene propylene diene monomer rubber, 15 - 25 parts of thermoplastic vulcanizate, 5 - 8 parts of epoxidized natural rubber, 12 - 15 parts of modified nano-silica, 25 - 35 parts of modified wollastonite, 3 - 5 parts of dispersant, 1 - 2 parts of antioxidant, 5 - 8 parts of vulcanizing agent, 3.5 - 6 parts of activator, 0.5 - 1 part of accelerator and 0.5 - 1 part of triethanolamine; The surface of the modified nano-silica is grafted with acrylic amino ester and acrylic fluoroester; The surface of the modified wollastonite is grafted with vinyl-terminated polybutadiene.

[0008] Preferably, in the ethylene propylene diene monomer rubber, the ethylene content is 60% - 70% and the diene content is 3% - 8%.

[0009] In this solution, thermoplastic vulcanizate, epoxidized natural rubber and ethylene propylene diene monomer rubber are blended. The thermoplastic vulcanizate forms a "sea-island structure" composed of dynamically vulcanized EPDM microdomains and polypropylene. Its unvulcanized EPDM chain segments are physically entangled with the matrix, significantly improving the interfacial bonding strength, inhibiting phase separation and molecular chain slippage during stretching, and endowing the material with creep resistance; meanwhile, the rigid polypropylene microdomains of the thermoplastic vulcanizate can enhance the compression deformation resistance. The epoxidized natural rubber reduces the interfacial tension through polar groups, promotes the dispersion of inorganic fillers, and enhances the adhesion between multiple phases through mild bonding, reducing the propagation of microcracks under high-pressure environments, and synergistically improving the densification and toughness of the material. The modified nano-silica and wollastonite respectively construct a "multi-scale waterproof barrier" through a nano-scale hydrophobic layer and a micron-scale needle-like skeleton. The former reduces the surface energy by means of fluorocarbon chain segments and forms a nano-scale hydrophobic layer to block molecular-level water penetration, while the latter constructs a micron-scale physical barrier network through oriented arrangement, combined with the dense cross-linked network formed by subsequent vulcanization, synergistically improving the densification, waterproofness and tensile strength of the material, enabling it to have good mechanical reliability and waterproof ability in the high-pressure and low-temperature environment of the seabed.

[0010] Preferably, the thermoplastic vulcanizate includes 30% - 50% by mass of polypropylene and 50% - 70% by mass of ethylene propylene diene monomer rubber.

[0011] Preferably, the epoxidized natural rubber is selected from any one of ENR-25, ENR-30, and ENR-50.

[0012] Preferably, the dispersant is cardanol polyoxyethylene ether.

[0013] Preferably, the antioxidant includes antioxidant 1010 and antioxidant 168.

[0014] Preferably, the vulcanizing agent is a phenolic resin.

[0015] Preferably, the activator includes zinc oxide and stearic acid.

[0016] Preferably, the accelerator is diphenylguanidine.

[0017] Preferably, the preparation method of the modified nano-silica includes the following steps: S11: Uniformly disperse nano-silica in an ethanol aqueous solution, add vinyl alkoxysilane, adjust the pH to 4.0 - 5.0, raise the temperature to 60 - 80 °C, react for 2 - 4 h, perform solid-liquid separation, wash, and dry to obtain silanized nano-silica; S12: Mix sodium dodecyl sulfonate, water, and glycerol evenly to obtain an aqueous phase; S13: Mix silanized nano-silica, acrylic amino ester, and acrylic fluoroester evenly, add them to the aqueous phase, under an inert atmosphere, add initiator A, raise the temperature to 60 - 80 °C, react for 3 - 5 h, cool, perform solid-liquid separation, wash, and dry to obtain the product.

[0018] In this solution, first, the acrylic amino ester effectively neutralizes the weak acidity of the silanol groups on the surface of nano-silica, avoiding interference with the vulcanization reaction of the ethylene propylene diene monomer (EPDM) matrix and ensuring the normal construction of the crosslinking network. Second, the grafted long-chain fluorocarbon groups and the alkyl chains of the acrylic amino ester construct a partial flexible buffer layer on the surface of the nanoparticles, converting the rigid interface of the nanoparticles into a flexible transition layer. When stretched, stress is absorbed through the deformation of the chain segments, significantly alleviating the problem of interfacial stress concentration. At the same time, the hydrophobicity of the fluorocarbon chain significantly reduces the water molecule permeability. In addition, during the subsequent vulcanization process, based on the catalytic effect of triethanolamine, the amino group in the bifunctional grafted layer, as a polar group, undergoes a partial ring-opening addition reaction with the epoxy group of epoxidized natural rubber to form a covalent bond, making the nano-silica a "reactive crosslinking point" and enhancing the binding force between the nano-silica and the epoxidized natural rubber.

[0019] Preferably, the particle size distribution of the nano-silica is 10 - 30 nm.

[0020] Preferably, the mass ratio of water, sodium dodecyl sulfonate, and glycerol is 1:(0.02 - 0.03):(0.05 - 0.1).

[0021] Preferably, the mass ratio of nano-silica, vinyl alkoxysilane, acrylic amino ester, and acrylic fluoroester is 1:(0.17 - 0.2):(0.1 - 0.15):(0.08 - 0.12).

[0022] Preferably, the dosage of initiator A is 0.5% - 1% of the total mass of acrylic amino ester and acrylic fluoroester.

[0023] Preferably, the initiator A is a persulfate.

[0024] Preferably, the acrylic amino ester is 2-aminoethyl methacrylate.

[0025] Preferably, the fluorinated acrylic ester is selected from any one of trifluoroethyl methacrylate and hexafluorobutyl methacrylate.

[0026] Preferably, the preparation method of the modified wollastonite comprises the following steps: S21: After acidifying wollastonite, it is uniformly dispersed in an ethanol aqueous solution, then vinylalkoxysilane is added and the pH is adjusted to 3-5, and the temperature is raised to 60-80 °C, and the reaction is carried out for 2-4 h. After solid-liquid separation, washing and drying, silanized wollastonite is obtained; S22: Under an inert atmosphere, the silanized wollastonite is uniformly dispersed in xylene, vinyl-terminated polybutadiene and initiator B are added, the temperature is raised to 100-120 °C, and the reaction is carried out for 7-9 h. After cooling, solid-liquid separation and washing are carried out to obtain the product.

[0027] Preferably, the wollastonite is acidified with dilute hydrochloric acid with a mass fraction of 4%-5% for 1.5-2.5 h, and after the treatment is completed, it is washed to neutral.

[0028] Preferably, the mass ratio of the wollastonite, vinylalkoxysilane and vinyl-terminated polybutadiene is 1: (0.05-0.2): (0.1-0.3).

[0029] Preferably, the particle size distribution of the wollastonite is 5-10 μm, and the aspect ratio is ≥5-10.

[0030] Preferably, the dosage of the initiator B is 1%-2% of the mass of the vinyl-terminated polybutadiene.

[0031] Preferably, the initiator B is dicumyl peroxide.

[0032] In this solution, the vinyl-terminated polybutadiene grafted on the surface of wollastonite undergoes mild cross-linking with the double bonds in the matrix under the action of subsequent vulcanizing agents and activators, constructing a "rigid needle-like skeleton-flexible grafted layer" composite structure, which not only improves the modulus through needle-like orientation, but also relieves the interfacial stress concentration through flexible chain segments, and cooperatively fills the matrix micropores and blocks seawater penetration.

[0033] Preferably, the waterproof and insulating material further comprises 8-10 parts by mass of a gradient copolymer, and the gradient copolymer is formed by gradient polymerization of ethylene → propylene → ethylidene norbornene.

[0034] Preferably, the preparation method of the gradient copolymer comprises the following steps: Under an inert atmosphere, the catalyst and the nonpolar solvent are mixed evenly, heated to 65-75 °C, the pressure is adjusted to 1.5-2.5 MPa, ethylene is introduced at a flow rate of 80-120 mL / min, after reacting for 15-25 min, within 25-35 min, the flow rate of ethylene is decreased from 80-120 mL / min to 0, and at the same time the flow rate of propylene is increased from 0 to 120-180 mL / min, heated to 80-90 °C, after continuing to react for 15-25 min, the flow rate of propylene is decreased from 120-180 mL / min to 0, and at the same time the flow rate of the ethylidene norbornene solution is increased from 0 to 150-240 mL / min, after continuing to react for 15-25 min, solid-liquid separation, washing, and drying are carried out to obtain the product.

[0035] Preferably, the catalyst includes a transition metal metallocene compound and an alkylaluminoxane.

[0036] Preferably, the mass ratio of the transition metal metallocene compound to the alkylaluminoxane is (4-6):(2-3).

[0037] Preferably, the mass-volume ratio of the catalyst to ethylene is (0.03-0.05) g:1 L.

[0038] Preferably, the ethylidene norbornene solution includes ethylidene norbornene and a nonpolar solvent, and the volume ratio of ethylidene norbornene to the nonpolar solvent is 1:(7-11).

[0039] Preferably, the nonpolar solvent is selected from any one of hexane and heptane.

[0040] In this solution, the gradient copolymer relieves the stress concentration at the hard-soft phase interface of ethylene-propylene-diene monomer rubber and thermoplastic vulcanizate through the molecular chain gradient structure, improving the matrix uniformity; the modified nano-silica and wollastonite achieve uniform dispersion of the fillers in the matrix through surface grafting of flexible chain segments and the action of dispersants, and the two cooperate to reduce the microcracks and water seepage channels under high pressure.

[0041] Preferably, the waterproof and insulating material further includes 3-4.5 parts by mass of vinyl-terminated polymethylvinylsiloxane.

[0042] In a second aspect, the present application provides a preparation method of an environmentally friendly waterproof and insulating material for use in the seabed, including the following steps: At a temperature of 100~120°C, ethylene propylene diene monomer rubber (EPDM), thermoplastic vulcanizate (TPV), and epoxidized natural rubber (ENR) are mixed for 10~15 min. Then, modified nano-silica, modified wollastonite, a dispersant, and an antioxidant are added, and mixing continues for 8~10 min. The temperature is adjusted to 90~100°C, triethanolamine is added, and mixing continues for 8~10 min. It is then transferred to a two-roll mill with the temperature set at 50~60°C and passed through thinly 6~10 times. Then it is transferred back to an internal mixer, the temperature is adjusted to 50~60°C, a vulcanizing agent, an activator, and an accelerator are added. After mixing for 8~10 min, it is subjected to mold vulcanization at a temperature of 160~170°C and a pressure of 10~15 MPa for 15~20 min. Then, it is kept warm at a temperature of 170~175°C for 60~90 min and then cooled to obtain the product.

[0043] In this solution, at 80~100°C, EPDM, TPV, and ENR are mixed to quickly form an interpenetrating compatible matrix network structure. Under the action of the dispersant, the modified nano-silica and the modified wollastonite are evenly dispersed in the matrix, laying the foundation for subsequent interface enhancement. Then, with the help of the alkaline catalytic action of triethanolamine, a partial ring-opening addition reaction occurs between the epoxy groups of ENR and the amino groups on the surface of nano-silica, enhancing the chemical anchoring between the filler and the matrix and reducing the hydrophilic sites, blocking the micro-water seepage channels from the source. Transferring to the two-roll mill and passing through thinly improves the material density and the uniformity of the phase structure. Adding the vulcanizing agent and the accelerator at a low temperature avoids scorching. After mold vulcanization, an initial cross-linked network is formed. Then, keeping warm at 170~175°C promotes complete cross-linking, which helps to form a uniform and dense multi-level enhanced structure, making the material have excellent waterproofness, mechanical properties, and interface stability.

[0044] Preferably, after adding the thermoplastic vulcanizate, the step of adding a gradient copolymer is further included.

[0045] Preferably, after adding the ethylene propylene diene monomer rubber, the step of adding vinyl-terminated polymethylvinylsiloxane is further included.

[0046] In summary, the present application has the following beneficial effects: 1. The present application uses a blend of thermoplastic vulcanizate and ethylene propylene diene monomer rubber. The "sea-island structure" of the thermoplastic vulcanizate enhances the interfacial bonding strength through physical entanglement, inhibits the molecular chain slippage during stretching, and endows the material with creep resistance and compression set resistance. The epoxy groups of the epoxidized natural rubber, under the catalysis of triethanolamine, undergo a ring-opening addition reaction with the amino groups on the surface of the modified nano-silica to form partial C-O-N covalent bonds, enhancing the chemical anchoring between the filler and the matrix. At the same time, as a polar compatibilizer, it reduces the interfacial tension, promotes the dispersion of the filler, and increases the cross-linking density, synergistically enhancing the mechanical properties and waterproof sealing of the material.

[0047] 2. The modified nano-silica of the present application forms a "polar anchoring layer - hydrophobic functional layer" by silanizing and grafting amino acrylate and fluoroacrylate. The amino group bonds with the epoxy group of epoxidized natural rubber, and the fluorocarbon chain reduces the surface energy and blocks molecular-level water penetration; the modified wollastonite is acidified and silanized and then grafted with vinyl-terminated polybutadiene. The vinyl end groups are slightly crosslinked with the double bonds in the matrix during vulcanization to construct a "rigid needle-like skeleton - flexible grafting layer", which not only extends the water penetration path through orientation arrangement but also relieves brittle fracture through flexible chain segments, and forms a "micro-nano waterproof barrier" synergistically with nano-silica, significantly improving the material density and seawater erosion resistance. Detailed Embodiment

[0048] The following further elaborates on the present application with reference to examples.

[0049] Unless otherwise specified, the raw materials in the examples and comparative examples of the present application are all commercially available.

[0050] In the following preparation examples: The particle size distribution of nano-silica is 10 - 30 nm; The particle size distribution of wollastonite is 5 - 10 μm, and the aspect ratio ≥ 5 - 10.

[0051] Preparation Examples 1 - 3 of Modified Nano-Silica Preparation Example 1 The preparation method of the modified nano-silica in this preparation example includes the following steps: S11: Add 300 g of nano-silica to 1500 mL of ethanol aqueous solution, transfer it to an ultrasonic device, set the ultrasonic frequency to 20 kHz, the ultrasonic power to 250 W, disperse ultrasonically for 30 min, add 55 g of vinyltrimethoxysilane, adjust the pH to 4.5 with 1 mol / L acetic acid, heat up to 70 °C, react for 3 h, centrifuge, wash twice with absolute ethanol, and dry at 60 °C to constant weight to obtain silanized nano-silica; S12: Mix 25 g of sodium dodecyl sulfate, 1000 g of deionized water, and 75 g of glycerol evenly to obtain an aqueous phase; S13: After mixing the silanized nano-silica, 36 g of 2-aminoethyl methacrylate, and 30 g of trifluoroethyl methacrylate, disperse ultrasonically for 20 min, slowly add it to the aqueous phase, under a nitrogen atmosphere, add 0.495 g of potassium persulfate and mix evenly, heat up to 70 °C, stir and react for 4 h, cool to room temperature, centrifuge, wash three times with deionized water, and dry at 60 °C to constant weight to obtain modified nano-silica.

[0052] Among them, the ethanol aqueous solution is composed of deionized water and ethanol mixed in a volume ratio of 1:2.

[0053] Preparation Example 2 The preparation method of the modified nano-silica in this preparation example comprises the following steps: S11: Add 300 g of nano-silica into 1500 mL of ethanol aqueous solution, transfer it into an ultrasonic device, set the ultrasonic frequency to 20 kHz, the ultrasonic power to 250 W, ultrasonically disperse for 30 min, add 51 g of vinyltrimethoxysilane, adjust the pH to 5 with 1 mol / L acetic acid, heat up to 60 °C, react for 4 h, perform centrifugal separation, wash twice with absolute ethanol, and dry at 60 °C to constant weight to obtain silylated nano-silica; S12: Mix 20 g of sodium dodecyl sulfate, 1000 g of deionized water and 50 g of glycerol evenly to obtain an aqueous phase; S13: After mixing the silylated nano-silica, 30 g of 2-aminoethyl methacrylate and 24 g of trifluoroethyl methacrylate, ultrasonically disperse for 20 min, slowly add it into the aqueous phase, under a nitrogen atmosphere, add 0.54 g of potassium persulfate and mix evenly, heat up to 60 °C, stir and react for 5 h, cool to room temperature, perform centrifugal separation, wash three times with deionized water, and dry at 60 °C to constant weight to obtain modified nano-silica.

[0054] Among them, the ethanol aqueous solution is composed of deionized water and ethanol mixed in a volume ratio of 1:3.

[0055] Preparation Example 3 The preparation method of the modified nano-silica in this preparation example comprises the following steps: S11: Add 300 g of nano-silica into 1500 mL of ethanol aqueous solution, transfer it into an ultrasonic device, set the ultrasonic frequency to 20 kHz, the ultrasonic power to 250 W, ultrasonically disperse for 30 min, add 60 g of vinyltrimethoxysilane, adjust the pH to 4 with 1 mol / L acetic acid, heat up to 80 °C, react for 2 h, perform centrifugal separation, wash twice with absolute ethanol, and dry at 60 °C to constant weight to obtain silylated nano-silica; S12: Mix 30 g of sodium dodecyl sulfate, 1000 g of deionized water and 100 g of glycerol evenly to obtain an aqueous phase; S13: After mixing the silylated nano-silica, 45 g of 2-aminoethyl methacrylate and 36 g of trifluoroethyl methacrylate, ultrasonically disperse for 20 min, slowly add it into the aqueous phase, under a nitrogen atmosphere, add 0.405 g of potassium persulfate and mix evenly, heat up to 80 °C, stir and react for 3 h, cool to room temperature, perform centrifugal separation, wash three times with deionized water, and dry at 60 °C to constant weight to obtain modified nano-silica.

[0056] Among them, the ethanol aqueous solution is composed of deionized water and ethanol mixed in a volume ratio of 1:1.

[0057] Preparation Examples 4 to 6 Modified Wollastonite Preparation Example 4 The preparation method of the modified wollastonite in this preparation example includes the following steps: S21: Place 700 g of wollastonite in dilute hydrochloric acid with a mass fraction of 4%, carry out acidification treatment for 2.5 h, filter, wash with deionized water until neutral, then add it to 3500 mL of an ethanol aqueous solution, transfer it to an ultrasonic device, set the ultrasonic frequency to 20 kHz, the ultrasonic power to 400 W, after ultrasonic dispersion for 30 min, add 35 g of vinyltrimethoxysilane, adjust the pH to 5 with dilute hydrochloric acid with a mass fraction of 4%, raise the temperature to 60 °C, react for 4 h, carry out centrifugal separation, wash 2 times with absolute ethanol, and dry at 60 °C to constant weight to obtain silanized wollastonite; S22: Under a nitrogen atmosphere, add the silanized wollastonite to 2100 mL of xylene, transfer it to an ultrasonic device, set the ultrasonic frequency to 20 kHz, the ultrasonic power to 400 W, after ultrasonic dispersion for 10 min, add 70 g of vinyl-terminated polybutadiene and 1.4 g of diisopropylbenzene peroxide, stir and mix evenly, raise the temperature to 100 °C, react for 9 h, cool to room temperature, filter, wash 2 times with xylene, and dry at 60 °C to constant weight to obtain the product.

[0058] Among them, the ethanol aqueous solution is composed of deionized water and ethanol mixed in a volume ratio of 1:3.

[0059] Preparation Example 5 The preparation method of the modified wollastonite in this preparation example includes the following steps: S21: Place 700 g of wollastonite in dilute hydrochloric acid with a mass fraction of 4.5%, carry out acidification treatment for 2 h, filter, wash with deionized water until neutral, then add it to 3500 mL of an ethanol aqueous solution, transfer it to an ultrasonic device, set the ultrasonic frequency to 20 kHz, the ultrasonic power to 400 W, after ultrasonic dispersion for 30 min, add 70 g of vinyltrimethoxysilane, adjust the pH to 4 with dilute hydrochloric acid with a mass fraction of 4.5%, raise the temperature to 70 °C, react for 3 h, carry out centrifugal separation, wash 2 times with absolute ethanol, and dry at 60 °C to constant weight to obtain silanized wollastonite; S22: Under a nitrogen atmosphere, add the silanized wollastonite to 2100 mL of xylene, transfer it to an ultrasonic device, set the ultrasonic frequency to 20 kHz, the ultrasonic power to 400 W, after ultrasonic dispersion for 10 min, add 140 g of vinyl-terminated polybutadiene and 2.1 g of diisopropylbenzene peroxide, stir and mix evenly, raise the temperature to 110 °C, react for 8 h, cool to room temperature, filter, wash 2 times with xylene, and dry at 60 °C to constant weight to obtain the product.

[0060] Among them, the ethanol aqueous solution is composed of deionized water and ethanol mixed in a volume ratio of 1:2.

[0061] Preparation Example 6 The preparation method of the modified wollastonite in this preparation example includes the following steps: S21: Place 700 g of wollastonite in dilute hydrochloric acid with a mass fraction of 5%, carry out acidification treatment for 1.5 h, filter, wash with deionized water until neutral, then add it to 3500 mL of ethanol aqueous solution, transfer it to an ultrasonic device, set the ultrasonic frequency to 20 kHz, the ultrasonic power to 400 W, after ultrasonic dispersion for 30 min, add 140 g of vinyltrimethoxysilane, adjust the pH to 3 with dilute hydrochloric acid with a mass fraction of 5%, raise the temperature to 80 °C, react for 2 h, carry out centrifugal separation, wash 2 times with absolute ethanol, and dry at 60 °C to constant weight to obtain silanized wollastonite; S22: Under a nitrogen atmosphere, add the silanized wollastonite to 2100 mL of xylene, transfer it to an ultrasonic device, set the ultrasonic frequency to 20 kHz, the ultrasonic power to 400 W, after ultrasonic dispersion for 10 min, add 210 g of vinyl-terminated polybutadiene and 2.1 g of diisopropylbenzene peroxide, stir and mix evenly, raise the temperature to 120 °C, react for 7 h, cool to room temperature, filter, wash 2 times with xylene, and dry at 60 °C to constant weight to obtain the product.

[0062] Among them, the ethanol aqueous solution is composed of deionized water and ethanol mixed in a volume ratio of 1:1.

[0063] Preparation Examples 7-9 Gradient Copolymer Preparation Example 7 The preparation method of the gradient copolymer in this preparation example includes the following steps: (1) Under a nitrogen atmosphere, add 55 mg of zirconocene dichloride to 100 mL of anhydrous hexane, stir and mix evenly, add 25 mL of methylaluminoxane solution, stir and mix evenly to obtain a catalyst; (2) Under a nitrogen atmosphere, 2 L of anhydrous hexane and the catalyst were mixed evenly, heated to 70 °C, the pressure was adjusted to 2 MPa, and ethylene gas was continuously introduced at a flow rate of 100 mL / min. After reacting for 20 min, within the next 30 min, the flow rate of ethylene gas was linearly decreased from 100 mL / min to 0 by a peristaltic pump, and at the same time, the flow rate of propylene gas was linearly increased from 0 to 150 mL / min. After the flow rate of ethylene gas dropped to 0 and the flow rate of propylene gas stabilized at 150 mL / min, the temperature was raised to 85 °C and the reaction continued for 20 min. Then, within the next 30 min, the flow rate of propylene gas was linearly decreased from 150 mL / min to 0 by a peristaltic pump, and at the same time, the flow rate of ethylidene norbornene solution was linearly increased from 0 to 200 mL / min. After the flow rate of propylene gas dropped to 0 and the flow rate of ethylidene norbornene solution stabilized at 200 mL / min, after reacting for 20 min, 70 mL of ethanol was added to quench the catalyst, the reaction mixture was poured into 5 L of methanol for precipitation, the solid product was separated by filtration, washed 3 times with methanol, and the solid product was vacuum dried at 60 °C for 12 h to obtain the product.

[0064] Among them, the methylaluminoxane solution includes methylaluminoxane and toluene, and the concentration of the methylaluminoxane solution is 10 g / L; The ethylidene norbornene solution includes ethylidene norbornene and anhydrous hexane, and the volume ratio of ethylidene norbornene to anhydrous hexane is 1:9.

[0065] Preparation Example 8 The preparation method of the gradient copolymer in this preparation example includes the following steps: (1) Under a nitrogen atmosphere, 40 mg of zirconocene dichloride was added to 80 mL of anhydrous heptane, stirred and mixed evenly, and 20 mL of methylaluminoxane solution was added, stirred and mixed evenly to obtain a catalyst; (2) Under a nitrogen atmosphere, 1.5 L of anhydrous heptane and the catalyst were mixed evenly, heated to 65 °C, the pressure was adjusted to 1.5 MPa, and ethylene gas was continuously introduced at a flow rate of 80 mL / min. After reacting for 15 min, within the next 25 min, the flow rate of ethylene gas was linearly decreased from 80 mL / min to 0 by a peristaltic pump, and at the same time, the flow rate of propylene gas was linearly increased from 0 to 120 mL / min. After the flow rate of ethylene gas dropped to 0 and the flow rate of propylene gas stabilized at 120 mL / min, the temperature was raised to 80 °C and the reaction continued for 15 min. Then, within the next 25 min, the flow rate of propylene gas was linearly decreased from 120 mL / min to 0 by a peristaltic pump, and at the same time, the flow rate of ethylidene norbornene solution was linearly increased from 0 to 150 mL / min. After the flow rate of propylene gas dropped to 0 and the flow rate of ethylidene norbornene solution stabilized at 150 mL / min, after reacting for 15 min, 50 mL of ethanol was added to quench the catalyst. The reaction mixture was poured into 4 L of methanol for precipitation, and the solid product was separated by filtration, washed 3 times with methanol, and the solid product was dried in vacuo at 60 °C for 10 h to obtain the product.

[0066] Among them, the methylaluminoxane solution includes methylaluminoxane and toluene, and the concentration of the methylaluminoxane solution is 10 g / L; The ethylidene norbornene solution includes ethylidene norbornene and anhydrous heptane, and the volume ratio of ethylidene norbornene to anhydrous heptane is 1:7.

[0067] Preparation Example 9 The preparation method of the gradient copolymer of this preparation example includes the following steps: (1) Under a nitrogen atmosphere, 60 mg of zirconocene dichloride was added to 120 mL of anhydrous heptane, stirred and mixed evenly, and 30 mL of methylaluminoxane solution was added, stirred and mixed evenly to obtain the catalyst; (2) Under a nitrogen atmosphere, 2.5 L of anhydrous heptane and the catalyst were mixed evenly, heated to 75 °C, the pressure was adjusted to 2.5 MPa, and ethylene gas was continuously introduced at a flow rate of 120 mL / min. After reacting for 25 min, within the next 35 min, the flow rate of ethylene gas was linearly decreased from 120 mL / min to 0 by a peristaltic pump, while the flow rate of propylene gas was linearly increased from 0 to 180 mL / min. After the flow rate of ethylene gas decreased to 0 and the flow rate of propylene gas stabilized at 180 mL / min, the temperature was raised to 80 °C and the reaction continued for 25 min. Then, within the next 35 min, the flow rate of propylene gas was linearly decreased from 180 mL / min to 0 by a peristaltic pump, while the flow rate of ethylidene norbornene solution was linearly increased from 0 to 240 mL / min. After the flow rate of propylene gas decreased to 0 and the flow rate of ethylidene norbornene solution stabilized at 240 mL / min, after reacting for 25 min, 100 mL of ethanol was added to quench the catalyst, the reaction mixture was poured into 6 L of methanol for precipitation, the solid product was separated by filtration, washed 3 times with methanol, and the solid product was dried in vacuum at 60 °C for 14 h to obtain the product.

[0068] Among them, the methylaluminoxane solution includes methylaluminoxane and toluene, and the concentration of the methylaluminoxane solution is 10 g / L; The ethylidene norbornene solution includes ethylidene norbornene and anhydrous heptane, and the volume ratio of ethylidene norbornene to anhydrous heptane is 1:11.

[0069] Example 1 The environment-friendly waterproof insulating material for the seabed in this example is prepared from the following raw materials: 1000 g of ethylene propylene diene monomer rubber, 150 g of thermoplastic vulcanizate, 50 g of epoxidized natural rubber, 120 g of modified nano-silica, 250 g of modified wollastonite, 30 g of dispersant, 10 g of antioxidant, 50 g of vulcanizing agent, 35 g of activator, 5 g of accelerator, and 5 g of triethanolamine; Among them, the modified nano-silica comes from Preparation Example 1; the modified wollastonite comes from Preparation Example 4; In the ethylene propylene diene monomer rubber, the ethylene content is 60% and the diene content is 3%; The thermoplastic vulcanizate includes 30% by mass of polypropylene and 70% by mass of ethylene propylene diene monomer rubber; The epoxidized natural rubber is ENR-25; The dispersant is cardanol polyoxyethylene ether; The antioxidant is 7 g of antioxidant 1010 and 3 g of antioxidant 168; The vulcanizing agent is octylphenol formaldehyde resin; The activator includes 30 g of zinc oxide and 5 g of stearic acid; The accelerator is diphenylguanidine.

[0070] The preparation method of the environment-friendly waterproof and insulating material for the seabed in this embodiment includes the following steps: Preheat the internal mixer to 100 °C, then put in ethylene propylene diene monomer (EPDM), thermoplastic vulcanizate (TPV) and epoxidized natural rubber, after mixing for 10 min, add modified nano-silica, modified wollastonite, dispersant and antioxidant, continue to mix for 8 min, cool down to 90 °C, add triethanolamine, continue to mix for 8 min, transfer to the open mill, control the roll temperature at 50 °C, thin pass 6 times, then transfer back to the internal mixer, adjust the temperature to 50 °C, add vulcanizing agent, activator and accelerator, mix for 8 min to obtain the rubber compound; put the rubber compound into a mold preheated to 160 °C, under a pressure of 10 MPa, carry out mold pressing and vulcanization for 15 min, then transfer to a hot air circulation furnace, at 170 °C, keep warm for 60 min, and naturally cool to room temperature to obtain the product.

[0071] Example 2 The environment-friendly waterproof and insulating material for the seabed in this embodiment is prepared from the following raw materials: 1000 g of ethylene propylene diene monomer (EPDM), 200 g of thermoplastic vulcanizate (TPV), 65 g of epoxidized natural rubber, 135 g of modified nano-silica, 300 g of modified wollastonite, 40 g of dispersant, 15 g of antioxidant, 65 g of vulcanizing agent, 47 g of activator, 7 g of accelerator and 7.5 g of triethanolamine; Among them, the modified nano-silica comes from Preparation Example 2; the modified wollastonite comes from Preparation Example 3; In the ethylene propylene diene monomer (EPDM), the ethylene content is 65% and the diolefin content is 5%; The thermoplastic vulcanizate (TPV) includes 40% by mass of polypropylene and 60% by mass of ethylene propylene diene monomer (EPDM); The epoxidized natural rubber is ENR-30; The dispersant is cardanol polyoxyethylene ether; The antioxidant is 10 g of antioxidant 1010 and 5 g of antioxidant 168; The vulcanizing agent is octylphenol formaldehyde resin; The activator includes 40 g of zinc oxide and 7 g of stearic acid; The accelerator is diphenylguanidine.

[0072] The preparation method of the environment-friendly waterproof and insulating material for the seabed in this embodiment includes the following steps: Preheat the internal mixer to 110°C, then add ethylene propylene diene monomer (EPDM), thermoplastic vulcanizate (TPV), and epoxidized natural rubber (ENR). After mixing for 13 minutes, add modified nano-silica, modified wollastonite, dispersant, and antioxidant, and continue mixing for 9 minutes. Cool down to 95°C, add triethanolamine, and continue mixing for 9 minutes. Transfer to an open mill, control the roll temperature at 55°C, thin-pass 8 times, then transfer back to the internal mixer, adjust the temperature to 55°C, add vulcanizing agent, activator, and accelerator, and mix for 9 minutes to obtain the rubber compound. Place the rubber compound into a mold preheated to 165°C, and under a pressure of 13 MPa, carry out mold pressing and vulcanization for 18 minutes, then transfer to a hot air circulation furnace, keep the temperature at 170°C for 75 minutes, and naturally cool to room temperature to obtain the product.

[0073] Example 3 The environment-friendly waterproof and insulating material for the seabed in this example is prepared from the following raw materials: 1000 g of ethylene propylene diene monomer (EPDM), 250 g of thermoplastic vulcanizate (TPV), 80 g of epoxidized natural rubber (ENR), 150 g of modified nano-silica, 350 g of modified wollastonite, 50 g of dispersant, 20 g of antioxidant, 80 g of vulcanizing agent, 60 g of activator, 10 g of accelerator, and 10 g of triethanolamine; Among them, the modified nano-silica is from Preparation Example 3; the modified wollastonite is from Preparation Example 6; In the ethylene propylene diene monomer (EPDM), the ethylene content is 70%, and the diene content is 8%; The thermoplastic vulcanizate (TPV) includes 50% by mass of polypropylene and 50% by mass of ethylene propylene diene monomer (EPDM); The epoxidized natural rubber is ENR-50; The dispersant is cardanol polyoxyethylene ether; The antioxidant is 15 g of antioxidant 1010 and 5 g of antioxidant 168; The vulcanizing agent is octylphenol formaldehyde resin; The activator includes 50 g of zinc oxide and 10 g of stearic acid; The accelerator is diphenylguanidine.

[0074] The preparation method of the environment-friendly waterproof and insulating material for the seabed in this example includes the following steps: Preheat the internal mixer to 120 °C, then add ethylene propylene diene monomer rubber, thermoplastic vulcanizate, and epoxidized natural rubber. After mixing for 15 min, add modified nano-silica, modified wollastonite, dispersant, and antioxidant, and continue mixing for 10 min. Cool down to 100 °C, add triethanolamine, and continue mixing for 10 min. Transfer to an open mill, control the roll temperature at 60 °C, thin pass 10 times, then transfer back to the internal mixer, adjust the temperature to 60 °C, add vulcanizing agent, activator, and accelerator, and mix for 10 min to obtain the rubber compound; put the rubber compound into a mold preheated to 170 °C, carry out compression molding and vulcanization at 15 MPa for 20 min, then transfer to a hot air circulation furnace, keep the temperature at 175 °C for 90 min, and naturally cool to room temperature to obtain the product.

[0075] Example 4 The difference between this example and Example 3 is that: The environment-friendly waterproof and insulating material for the seabed in this example further includes 80 g of gradient copolymer.

[0076] In the preparation method of the environment-friendly waterproof and insulating material for the seabed in this example, after the thermoplastic vulcanizate, a step of adding the gradient copolymer is further included.

[0077] Among them, the gradient copolymer is from Preparation Example 7.

[0078] Other steps are the same as those in Example 3.

[0079] Example 5 The difference between this example and Example 4 is that: The dosage of the gradient copolymer is 90 g; the gradient copolymer is from Preparation Example 8.

[0080] Other steps are the same as those in Example 4.

[0081] Example 6 The difference between this example and Example 5 is that: The dosage of the gradient copolymer is 100 g; the gradient copolymer is from Preparation Example 9.

[0082] The environment-friendly waterproof and insulating material for the seabed in this example further includes 30 g of vinyl-terminated polymethylvinylsiloxane.

[0083] In the preparation method of the environment-friendly waterproof and insulating material for the seabed in this example, after the ethylene propylene diene monomer rubber, a step of adding vinyl-terminated polymethylvinylsiloxane is further included.

[0084] Other steps are the same as those in Example 5.

[0085] Example 7 The difference between this example and Example 6 is that: The dosage of vinyl-terminated polymethylvinylsiloxane is 45 g.

[0086] Others are the same as in Example 6.

[0087] Comparative Example 1 The difference between this comparative example and Example 1 is that: Thermoplastic vulcanizate was not added in this comparative example; Others are the same as in Example 1.

[0088] Comparative Example 2 The difference between this comparative example and Example 1 is that: The preparation method of modified nano-silica includes the following steps: Add 300 g of nano-silica into 1500 mL of ethanol aqueous solution, transfer it into an ultrasonic device, set the ultrasonic frequency at 20 kHz, the ultrasonic power at 250 W, disperse ultrasonically for 30 min, add 19.5 g of vinyltrimethoxysilane, adjust the pH to 4.5 with 1 mol / L acetic acid, heat up to 70 °C, react for 3 h, centrifuge and separate, wash twice with absolute ethanol, and dry at 60 °C to constant weight to obtain.

[0089] Others are the same as in Example 1.

[0090] Comparative Example 3 The difference between this comparative example and Example 1 is that: The preparation method of modified wollastonite includes the following steps: Place 700 g of wollastonite in dilute hydrochloric acid with a mass fraction of 4%, carry out acidification treatment for 2.5 h, filter, wash with deionized water until neutral, then add it into 3500 mL of ethanol aqueous solution, transfer it into an ultrasonic device, set the ultrasonic frequency at 20 kHz, the ultrasonic power at 400 W, disperse ultrasonically for 30 min, add 35 g of vinyltrimethoxysilane, adjust the pH to 5 with dilute hydrochloric acid with a mass fraction of 4%, heat up to 60 °C, react for 4 h, centrifuge and separate, wash twice with absolute ethanol, and dry at 60 °C to constant weight to obtain.

[0091] Others are the same as in Example 1.

[0092] Performance detection test Place the environmentally friendly waterproof and insulating materials for the seabed prepared in Examples 1 to 7 and Comparative Examples 1 to 3 in an environment of 23 ± 2 °C and a relative humidity of 50 ± 5%, after adjusting for 24 h, then prepare the corresponding specimens respectively according to the following requirements for standby.

[0093] 1. Water absorption rate Reference standard: ASTM D471-16a (2021) Specimen size: diameter 50 mm ± 1 mm, thickness 2.0 mm ± 0.2 mm Take 5 specimens, dry them to constant weight at 50 °C (accuracy 0.1 mg), completely immerse them in deionized water at 23 ± 2 °C, take them out after 48 h, dry the surface moisture with filter paper, weigh them immediately, calculate the water absorption rate, and take the average value of 5 times. The specific results are shown in Table 1.

[0094] 2. Volume Resistivity Reference Standard: GB / T 1410-2006 Specimen Size: Circular Disc with Φ100 mm × Thickness 2 mm Use a high resistance meter (range ≥ 10 18 Ω), apply a DC voltage of 100 V, read the leakage current after stabilizing for 1 min, and calculate the volume resistivity. The specific results are shown in Table 1.

[0095] 3. Tensile Strength Reference Standard: GB / T 528-2009 Specimen Size: Dumbbell Type I (Gauge Length 25 mm, Width 6 mm, Thickness 2 mm) Use an electronic universal testing machine, adjust the clamping distance to 50 mm, the tensile rate to 500 mm / min, record the maximum tensile force (N) and the gauge length at break, and calculate the tensile strength and elongation at break. The specific results are shown in Table 1.

[0096] 4. Salt Spray Test Reference Standard: GB / T 10125-2021 Specimen Size: 50 mm × 50 mm × 2 mm (no surface defects) Take 5 specimens and place them in the test chamber, set the temperature to 35 ± 2 °C, use a sodium chloride solution with a mass fraction of 5%, pH about 7, adjust the spray pressure to 0.1 MPa, continuously spray for 96 h, and measure the weight change rate and tensile strength retention rate. The specific results are shown in Table 1.

[0097] 5. Compression Set Reference Standard: GB / T 7759.1-2015 Specimen Size: Φ29 mm × Thickness 12.5 mm At a compression rate of 25%, place it in an oven at 70 °C for 22 h, take it out and recover in an environment of 23 ± 2 °C for 30 min, measure the residual thickness with a thickness gauge with an accuracy of 0.01 mm (take the average value of 3 measurements). The specific results are shown in Table 1.

[0098] Table 1 Test Results of Performance Detection for Examples 1 - 7 and Comparative Examples 1 - 3

[0099] Combined with the performance detection data in Table 1, by analyzing Examples 1-3 and Comparative Examples 1-3, it can be seen that: through the blending modification of ethylene propylene diene monomer rubber (EPDM), thermoplastic vulcanizate (TPV), and epoxidized natural rubber (ENR) and the surface treatment of fillers, the water resistance, mechanical properties, and salt spray resistance of the materials are significantly improved. This is mainly based on the following: TPV enhances the rigidity and toughness of the material through the "hard segment crystallization - soft segment elasticity" double network, and at the same time acts as a compatibilizer to improve the compatibility between EPDM and ENR, reducing the phase separation defects. The epoxy groups of ENR form a mild bond with the modified fillers, strengthening the interfacial adhesion between the fillers and the matrix, and constructing a "polar transition layer" to block the penetration of moisture. After the fillers are silanized grafted and coated with flexible chains, the dispersibility is significantly improved, and the hydrophobic / hydrophilic groups on their surfaces form multiple interactions with the blend matrix, simultaneously optimizing the water resistance, mechanical strength, and salt spray resistance of the materials.

[0100] By analyzing Examples 3-5, it can be seen that: the addition of the gradient copolymer regulates the phase state of the material through the gradient distribution of molecular chains, further optimizing the performance of the insulating material. This is mainly based on the following: the gradient structure forms a transition phase in the EPDM / TPV matrix, alleviating the stress concentration at the hard / soft phase interface, enabling the material to uniformly transfer the load through the gradient structure during stretching, and improving the elongation at break and fatigue resistance.

[0101] By analyzing Examples 5-7, it can be seen that: the addition of vinyl-terminated polymethylvinylsiloxane further improves the waterproof performance and mechanical properties of the insulating material. This is mainly based on the following: vinyl-terminated polymethylvinylsiloxane undergoes partial crosslinking with the double bonds in the matrix to form a "rubber - siloxane" interpenetrating network. Its flexible Si-O-Si chain segments improve the ductility of the material while inhibiting crack propagation through an energy dissipation mechanism, achieving a synergistic enhancement of the tensile strength and elongation at break. The low surface energy characteristics of the siloxane chain segments and the internal dense crosslinked network work together to reduce the moisture penetration path.

[0102] This specific embodiment is only an explanation of the present application and does not limit the present application. After reading this specification, those skilled in the art can make modifications to this embodiment without creative contributions as needed, but as long as it is within the scope of the claims of the present application, it is protected by the patent law.

Claims

1. An environmentally friendly waterproof and insulating material for use in the seabed, characterized in that, It is prepared from raw materials including the following parts by mass: 100 parts of ethylene propylene diene monomer rubber, 15 - 25 parts of thermoplastic vulcanizate, 5 - 8 parts of epoxidized natural rubber, 12 - 15 parts of modified nano - silica, 25 - 35 parts of modified wollastonite, 3 - 5 parts of dispersant, 1 - 2 parts of antioxidant, 5 - 8 parts of vulcanizing agent, 3.5 - 6 parts of activator, 0.5 - 1 part of accelerator and 0.5 - 1 part of triethanolamine; The surface of the modified nano - silica is grafted with acrylate amino - ester and fluoro - acrylate; The surface of the modified wollastonite is grafted with vinyl - terminated polybutadiene.

2. The environmentally friendly waterproof and insulating material for the seabed according to claim 1, characterized in that, In the ethylene propylene diene monomer rubber, the ethylene content is 60% - 70%, and the diene content is 3% - 8%.

3. The environmentally friendly waterproof and insulating material for seabed use according to claim 1, wherein, The preparation method of the modified nano - silica includes the following steps: S11: Uniformly disperse nano - silica in an ethanol - aqueous solution, add vinyl alkoxysilane, adjust the pH to 4.0 - 5.0, raise the temperature to 60 - 80 °C, react for 2 - 4 h, carry out solid - liquid separation, washing, and drying to obtain silanized nano - silica; S12: Mix sodium dodecyl sulfonate, water and glycerol evenly to obtain an aqueous phase; S13: Mix the silanized nano - silica, acrylate amino - ester and fluoro - acrylate evenly, add them to the aqueous phase, add initiator A under an inert atmosphere, raise the temperature to 60 - 80 °C, react for 3 - 5 h, cool, carry out solid - liquid separation, washing, and drying to obtain the product.

4. The environmentally friendly waterproof and insulating material for underwater use according to claim 3, characterized in that, The mass ratio of the nano - silica, vinyl alkoxysilane, acrylate amino - ester and fluoro - acrylate is 1:(0.17 - 0.2):(0.1 - 0.15):(0.08 - 0.12).

5. The environmentally friendly waterproof and insulating material for seabed use according to claim 1, characterized in that, The preparation method of the modified wollastonite includes the following steps: S21: After acidifying wollastonite, uniformly disperse it in an ethanol - aqueous solution, then add vinyl alkoxysilane and adjust the pH to 3 - 5, raise the temperature to 60 - 80 °C, react for 2 - 4 h, carry out solid - liquid separation, washing, and drying to obtain silanized wollastonite; S22: Under an inert atmosphere, uniformly disperse the silanized wollastonite in xylene, add vinyl - terminated polybutadiene and initiator B, raise the temperature to 100 - 120 °C, react for 7 - 9 h, cool, carry out solid - liquid separation, washing to obtain the product.

6. The environmentally friendly waterproof and insulating material for underwater use according to claim 5, characterized in that, The mass ratio of the wollastonite, vinyl alkoxysilane and vinyl - terminated polybutadiene is 1:(0.05 - 0.2):(0.1 - 0.3).

7. The environmentally friendly waterproof insulating material for seabed use according to claim 1, characterized in that, The waterproof and insulating material also includes 8 - 10 parts by mass of a gradient copolymer, and the gradient copolymer is formed by gradient polymerization of ethylene → propylene → ethylidene norbornene.

8. The environmentally friendly waterproof and insulating material for the seabed according to claim 7, characterized in that, The preparation method of the gradient copolymer includes the following steps: Under an inert atmosphere, the catalyst and the nonpolar solvent are mixed evenly, the temperature is raised to 65-75 °C, the pressure is adjusted to 1.5-2.5 MPa, ethylene is introduced at a flow rate of 80-120 mL / min. After reacting for 15-25 min, within 25-35 min, the flow rate of ethylene is decreased from 80-120 mL / min to 0, and at the same time the flow rate of propylene is increased from 0 to 120-180 mL / min. The temperature is raised to 80-90 °C and the reaction continues for 15-25 min. Then the flow rate of propylene is decreased from 120-180 mL / min to 0, and at the same time the flow rate of ethylidene norbornene solution is increased from 0 to 150-240 mL / min. After reacting for 15-25 min, solid-liquid separation, washing, and drying are carried out to obtain the product.

9. A preparation method of the environment-friendly waterproof insulating material for the seabed according to any one of claims 1 to 8, characterized in that, It includes the following steps: At a temperature of 100-120 °C, ethylene-propylene-diene rubber, thermoplastic vulcanizate, and epoxidized natural rubber are mixed and kneaded for 10-15 min. Modified nano-silica, modified wollastonite, dispersant, and antioxidant are added, and kneading continues for 8-10 min. The temperature is adjusted to 90-100 °C, triethanolamine is added, and kneading continues for 8-10 min. It is transferred to an open mill with the temperature set at 50-60 °C and passed thinly 6-10 times. Then it is transferred to an internal mixer with the temperature adjusted to 50-60 °C. A vulcanizing agent, activator, and accelerator are added, and after kneading for 8-10 min, it is molded and vulcanized at a temperature of 160-170 °C and a pressure of 10-15 MPa for 15-20 min. Then it is kept warm at a temperature of 170-175 °C for 60-90 min and cooled to obtain the product.

10. The preparation method of the environment-friendly waterproof insulating material for seabed use according to claim 9, characterized in that: After adding the thermoplastic vulcanizate, it further includes the step of adding a gradient copolymer.

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