Multi-dimensional enhanced silane cross-linked chlorosulfonated polyethylene nano composite material as well as preparation method and application thereof

Abstract

The invention relates to a multi-dimensional reinforced silane cross-linked chlorosulfonated polyethylene nano composite material as well as a preparation method and application thereof, and belongs to the technical field of high-performance special rubber composite materials. The technical scheme is as follows: the composite material comprises the following components in parts by weight: 100 parts of chlorosulfonated polyethylene, 3-15 parts of a compound silane crosslinking system, 5-30 parts of a multi-dimensional nano reinforced phase, 1-8 parts of a hyperbranched polymer modifier, 5-20 parts of an environment-friendly plasticizer, 0.1-2 parts of a catalyst, 10-60 parts of filler and 2-8 parts of a functional aid. The material is obviously superior to the prior art in the aspects of heat resistance grade, mechanical property, chemical medium resistance, electrical insulation characteristic, compression set and the like, and can be widely applied to the field of high-end equipment for extreme environments, such as nuclear power cables, deep sea oil exploitation, new energy automobiles, space flight and aviation, geothermal exploration and the like.

Description

Technical Field

[0001] This invention relates to a multidimensional reinforced silane crosslinked chlorosulfonated polyethylene nanocomposite material, its preparation method, and its application. Specifically, it relates to a silane crosslinked chlorosulfonated polyethylene nanocomposite material and its preparation method based on a triple network synergistic reinforcement mechanism of "chemical grafting-nano reinforcement-topological entanglement," and its application in high-end equipment for extreme environments, belonging to the field of high-performance special rubber composite materials technology. Background Technology

[0002] Chlorosulfonated polyethylene (CSM) is a special rubber produced by the chlorination and chlorosulfonation reaction of polyethylene. Its molecular chain contains chlorine atoms and sulfonyl chloride groups, giving the material excellent weather resistance, ozone resistance, heat resistance, and chemical resistance. Since DuPont industrialized it in 1952, CSM has been widely used in wire and cable, automotive industry, and anti-corrosion lining.

[0003] However, as modern industry extends into extreme environments (high temperature, high pressure, strong corrosion, strong radiation), higher demands are placed on material properties. Traditional CSM vulcanization systems face the following insurmountable bottlenecks:

[0004] (1) Environmental defects of the vulcanization system

[0005] Traditional CSM (Continuous Molding Sandwich) mainly uses metal oxides (especially lead oxide), organic peroxides, or polyamines for vulcanization. Although lead-based systems have good vulcanization effects, they are highly toxic and have been strictly restricted by international environmental regulations such as RoHS and REACH. Peroxide systems are prone to scorching and are sensitive to acidic fillers, with a narrow processing window. Polyamine systems have poor storage stability and are prone to blooming.

[0006] (2) The cross-linking network structure is simple.

[0007] Traditional vulcanization systems form cross-linked networks primarily composed of C-C bonds or metal ion coordination bonds, resulting in a simple network structure that struggles to meet the comprehensive performance requirements of materials under multi-field coupled service environments. Especially under the synergistic effects of high temperature, high pressure, and chemical media, traditional cross-linked networks are prone to damage, leading to material failure.

[0008] (3) Insufficient heat resistance rating

[0009] Conventional CSM vulcanizates typically have a long-term service temperature of no more than 125°C, which is insufficient to meet the heat resistance requirements of emerging fields such as nuclear power, geothermal energy, and deep sea, which require temperatures above 150°C.

[0010] (4) Large compression set

[0011] The cross-linked network formed by traditional vulcanization systems is uneven and prone to stress relaxation under long-term compression, affecting the long-term reliability of the seals.

[0012] (5) Low reinforcement efficiency of filler

[0013] Conventional micron-sized fillers have weak interfacial bonding with the CSM matrix, resulting in limited reinforcement efficiency and making it difficult to meet the requirements of high-strength and high-wear-resistance applications.

[0014] Silane crosslinking technology is a mature and environmentally friendly crosslinking technology in the field of polyolefin materials. It forms a -Si-O-Si- three-dimensional network through silane grafting and hydrolysis condensation. In recent years, researchers have attempted to introduce this technology into the CSM system. For example, Chinese patent application CN107851489A involves silane crosslinking technology for halogen-containing polymers. However, existing technologies mainly focus on simple grafting and crosslinking of silane on CSM, which has the following problems: (1) the crosslinking network structure is simple and lacks multi-level structural design; (2) the synergistic effect between the nano-reinforcing phase and the silane network is not effectively utilized; (3) the improvement of heat resistance is limited and it is difficult to meet the long-term use requirements above 150℃; (4) there is a lack of systematic consideration of the material failure mechanism under extreme environments.

[0015] To address the aforementioned issues, this invention proposes a novel triple network synergistic enhancement mechanism of "chemical grafting-nano-reinforcement-topological entanglement," which achieves a comprehensive breakthrough in the performance of CSM composite materials through molecular design, nanocomposite technology, and topological structure regulation. Summary of the Invention

[0016] The purpose of this invention is to provide a multidimensional reinforced silane crosslinked chlorosulfonated polyethylene nanocomposite material, its preparation method, and its application. By constructing a triple network synergistic reinforcement structure, the material's heat resistance, mechanical properties, chemical resistance, and long-term service reliability are comprehensively improved, meeting the stringent requirements of high-end equipment for extreme environments and solving the aforementioned problems in the prior art.

[0017] The technical solution of this invention is:

[0018] A multidimensional reinforced silane crosslinked chlorosulfonated polyethylene nanocomposite material, comprising the following components by weight: chlorosulfonated polyethylene: 100 parts; compounded silane crosslinking system: 3-15 parts; multidimensional nano-reinforcing phase: 5-30 parts; hyperbranched polymer modifier: 1-8 parts; environmentally friendly plasticizer: 5-20 parts; catalyst: 0.1-2 parts; filler: 10-60 parts; functional additives: 2-8 parts.

[0019] Furthermore, the compounded silane crosslinking system is composed of grafted silane and crosslinked silane in a mass ratio of 1:0.3-1:2; wherein the grafted silane is at least one of vinyltrimethoxysilane, vinyltriethoxysilane or γ-methacryloxypropyltrimethoxysilane; and the crosslinked silane is at least one of γ-aminopropyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane or bis-[γ-(triethoxysilyl)propyl]tetrasulfide.

[0020] Furthermore, the multidimensional nano-reinforcing phase is a multi-component composite system of functionalized zero-dimensional nanoparticles, one-dimensional nanomaterials, and two-dimensional nanomaterials; the zero-dimensional nanoparticles are nano-silica with surface grafted amino or epoxy groups, and a particle size of 5-30 nm; the one-dimensional nanomaterials are carboxylated or hydroxylated carbon nanotubes with a diameter of 10-30 nm and a length of 1-20 μm; the two-dimensional nanomaterials are layered double hydroxides or modified montmorillonite, with a sheet thickness of 1-3 nm and an aspect ratio >100; the mass ratio of the three is zero-dimensional: one-dimensional: two-dimensional = 1:0.1-0.5:0.2-1.

[0021] Furthermore, the hyperbranched polymer modifier is at least one of amino-terminated hyperbranched polyester, hydroxyl-terminated hyperbranched polyamide, or hyperbranched polysiloxane, with a number-average molecular weight of 2000-20000 and a branching degree ≥0.6.

[0022] Furthermore, the environmentally friendly plasticizer is at least one of polyester plasticizer, epoxy fatty acid methyl ester or citrate plasticizer; the catalyst is at least one of dibutyltin dilaurate, dibutyltin diacetate or organic bismuth catalyst.

[0023] Furthermore, the filler is at least one of calcined clay, talc powder, and mica powder; the functional additives include antioxidants, light stabilizers, anti-aging agents, and processing aids.

[0024] The above-described method for producing multidimensional reinforced silane crosslinked chlorosulfonated polyethylene nanocomposites includes the following steps:

[0025] (1) Synergistic functionalization of multidimensional nano-reinforced phase: Nano-silica, carbon nanotubes and layered double hydroxides are dispersed in an ethanol / water mixed solvent according to the ratio, silane coupling agent KH-560 is added, the pH is adjusted to 4-5, and the reaction is carried out with ultrasonic assistance at 60-80°C for 2-4 hours. After filtration, washing and vacuum drying, synergistic functionalized multidimensional nano-reinforced phase is obtained; (2) Pre-dispersion of hyperbranched polymer: Chlorosulfonated polyethylene and hyperbranched polymer are pre-dispersioned. The modifier is premixed in a mixer at 90-110°C for 5-10 minutes to uniformly disperse the hyperbranched polymer in the CSM matrix to form a pre-dispersion masterbatch; (3) Grafting reaction: some filler, grafted silane and initiator are added to the pre-dispersion masterbatch in step (2), the temperature is raised to 110-130°C, and the reaction is carried out under nitrogen protection for 10-25 minutes to graft the grafted silane onto the CSM molecular chain to obtain the grafted masterbatch; (4) Multidimensional nano-enhancing Strong phase composite: Cool the grafted masterbatch from step (3) to 80-100°C, add the synergistically functionalized multidimensional nano-reinforcing phase and cross-linked silane, and mix at high speed for 8-15 minutes to make the nanomaterials uniformly dispersed and react in situ; (5) Catalysis and final mixing: Cool the mixture from step (4) to below 60°C, add the catalyst, environmentally friendly plasticizer, remaining filler and functional additives, and mix evenly on a two-roll mill to produce sheets; (6) Molding and programmed cross-linking: The final mixed rubber is made into products by extrusion, calendering or molding, and a three-stage programmed cross-linking process is adopted: first, it is treated at 80-90°C and 60-70% relative humidity for 4-8 hours to complete surface cross-linking; then, it is treated at 100-110°C and 80-90% relative humidity for 8-16 hours to complete bulk cross-linking; finally, it is treated at 120-130°C in a dry environment for 2-4 hours to complete post-curing and residual silanol condensation.

[0026] Furthermore, in step (1), the ultrasonic power of the ultrasonic-assisted reaction is 200-500W and the frequency is 20-40kHz; in step (6), the temperature, humidity and time of each stage of the three-stage crosslinking process can be optimized and adjusted according to the thickness of the product to meet the matching relationship between the thickness of the product and the uniformity of crosslinking.

[0027] Further, the initiator is at least one of dicumyl peroxide, 1,4-di-tert-butylperoxypropylbenzene, or 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, and its addition amount is 0.5-2.5% of the mass of chlorosulfonated polyethylene.

[0028] The above-mentioned multidimensional reinforced silane crosslinked chlorosulfonated polyethylene nanocomposites are used in the preparation of nuclear power cable insulation layers, deep-sea oil extraction equipment seals, new energy vehicle high-voltage connection systems, aerospace hydraulic seals, or geothermal exploration equipment sealing elements.

[0029] The core innovation of this invention lies in:

[0030] 1. Structural Innovation: For the first time, a triple network synergistic enhancement mechanism of "chemical grafting-nano reinforcement-topological entanglement" is proposed, realizing structural innovation of CSM composite materials.

[0031] Materials Innovation: For the first time, a multidimensional nanomaterial composite system and hyperbranched polymers are introduced into a silane crosslinked CSM system to exert a synergistic enhancement effect.

[0032] 2. Process innovation: Develop a "stepwise grafting-gradient catalysis-programmed crosslinking" process route to achieve hierarchical control of the triple network structure.

[0033] 3. Performance breakthrough: The long-term operating temperature of CSM has been increased from 125℃ to 150℃, compression set has been reduced by more than 50%, and electrical performance has been improved by an order of magnitude.

[0034] 4. Application Expansion: Expanding the application fields of CSM to extreme environments such as nuclear power, deep sea, aerospace, and geothermal energy, filling the technological gap of high-performance CSM composite materials in these fields.

[0035] The positive effects of this invention: By innovatively constructing a triple-network synergistic reinforcement structure of "chemical grafting-nano-reinforcement-topological entanglement," and introducing a multi-dimensional nanomaterial compound system, hyperbranched polymer modifier, and programmed crosslinking process, this invention has successfully developed a chlorosulfonated polyethylene nanocomposite material with excellent comprehensive performance. This material significantly outperforms existing technologies in terms of heat resistance, mechanical properties, chemical resistance, electrical insulation properties, and compression set. It has a long-term operating temperature of up to 150℃, a volume resistivity >10^16 Ω·cm, and a compression set <15% (100℃×24h). It can be widely used in high-end equipment fields for extreme environments such as nuclear power cables, deep-sea oil extraction, new energy vehicles, aerospace, and geothermal exploration. Detailed Implementation

[0036] The present invention will be further described below with reference to embodiments:

[0037] A multidimensional reinforced silane crosslinked chlorosulfonated polyethylene nanocomposite material, comprising the following components by weight: chlorosulfonated polyethylene: 100 parts; compounded silane crosslinking system: 3-15 parts; multidimensional nano-reinforcing phase: 5-30 parts; hyperbranched polymer modifier: 1-8 parts; environmentally friendly plasticizer: 5-20 parts; catalyst: 0.1-2 parts; filler: 10-60 parts; functional additives: 2-8 parts.

[0038] The compounded silane crosslinking system is composed of grafted silane and crosslinked silane in a mass ratio of 1:0.3-1:2; wherein the grafted silane is at least one of vinyltrimethoxysilane, vinyltriethoxysilane or γ-methacryloxypropyltrimethoxysilane; and the crosslinked silane is at least one of γ-aminopropyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane or bis-[γ-(triethoxysilane)propyl]tetrasulfide.

[0039] The multidimensional nano-reinforcing phase is a multi-component composite system of functionalized zero-dimensional nanoparticles, one-dimensional nanomaterials, and two-dimensional nanomaterials; the zero-dimensional nanoparticles are nano-silica with surface-grafted amino or epoxy groups, with a particle size of 5-30 nm; the one-dimensional nanomaterials are carboxylated or hydroxylated carbon nanotubes with a diameter of 10-30 nm and a length of 1-20 μm; the two-dimensional nanomaterials are layered double hydroxides or modified montmorillonite, with a sheet thickness of 1-3 nm and an aspect ratio >100; the mass ratio of the three is zero-dimensional: one-dimensional: two-dimensional = 1:0.1-0.5:0.2-1.

[0040] The hyperbranched polymer modifier is at least one of amino-terminated hyperbranched polyester, hydroxyl-terminated hyperbranched polyamide, or hyperbranched polysiloxane, with a number-average molecular weight of 2000-20000 and a branching degree ≥0.6.

[0041] The environmentally friendly plasticizer is at least one of polyester plasticizer, epoxy fatty acid methyl ester or citrate plasticizer; the catalyst is at least one of dibutyltin dilaurate, dibutyltin diacetate or organic bismuth catalyst.

[0042] The filler is at least one of calcined clay, talc powder, and mica powder; the functional additives include antioxidants, light stabilizers, anti-aging agents, and processing aids.

[0043] The core technical concept of this invention lies in constructing a triple network structure to achieve a synergistic enhancement effect:

[0044] First-layer network: silane chemical grafting cross-linking network

[0045] A complex silane system is employed: grafted silanes (vinylsilanes) are grafted onto the CSM molecular chain via free radical reaction initiated by peroxides; cross-linked silanes (aminosilanes or epoxysilanes) can react chemically with the sulfonyl chloride groups on the CSM molecular chain through their organic functional groups, and their alkoxy groups undergo hydrolysis and condensation under humid conditions to form -Si-O-Si- chemical cross-linking bonds. This complex design achieves multiple anchoring and controllable cross-linking of silanes on CSM.

[0046] Second layer network: Multidimensional nano-enhanced network

[0047] An innovative multi-component nanomaterial composite system consisting of zero-dimensional (nano-SiO2), one-dimensional (carbon nanotubes), and two-dimensional (layered double hydroxides) nanomaterials is proposed. Through synergistic functionalization, active groups capable of reacting with silane networks are introduced onto the surface of the nanomaterials. During the cross-linking process, these functionalized nanomaterials integrate into the silane network via chemical bonding, forming an integrated "nanofiller-silane network" structure, achieving multi-dimensional nano-reinforcement.

[0048] Third-layer network: Hyperbranched polymeric topological entanglement network

[0049] Hyperbranched polymers are introduced as topology modifiers. Hyperbranched polymers have highly branched three-dimensional spherical structures and a large number of terminal functional groups, which can form physical entanglement points in the CSM matrix and participate in silane hydrolysis and condensation reactions, introducing topology into the crosslinked network, increasing network complexity and energy dissipation mechanisms.

[0050] The three networks work synergistically through chemical bonding and physical entanglement: the silane network provides the basic cross-linked structure; the nano-reinforcing network enhances mechanical properties and thermal stability through nano-effects and interfacial bonding; and the hyperbranched polymer topology network improves toughness and creep resistance through entanglement and energy dissipation. The synergistic effect of these three networks achieves a reinforcement effect greater than the sum of its parts (1+1+1>3).

[0051] The component selection and mechanism of action of this invention are as follows:

[0052] (1) Chlorosulfonated polyethylene (CSM)

[0053] As a matrix material, it provides basic properties. Preferred CSMs have a chlorine content of 25-40% and a sulfonyl chloride content of 0.8-1.8%, such as Hypalon 40, Hypalon 45, or domestically produced CSM-40. An appropriate sulfonyl chloride content ensures chemical reactivity with cross-linked silanes while avoiding excessive cross-linking that could lead to processing difficulties.

[0054] (2) Composite silane crosslinking system

[0055] Grafted silanes: vinyltrimethoxysilane, vinyltriethoxysilane, or γ-methacryloyloxypropyltrimethoxysilane. Their double bonds generate free radicals under the initiation of peroxides, which undergo grafting reactions with active sites on the CSM molecular chain, introducing silane groups into the CSM backbone.

[0056] Crosslinked silanes: γ-aminopropyltriethoxysilane (KH-550), γ-glycidoxypropyltrimethoxysilane (KH-560), or bis-[γ-(triethoxysilyl)propyl]tetrasulfide (Si-69). Specifically: the amino group of KH-550 can react with the sulfonyl chloride group of CSM to form a sulfonamide bond, achieving chemical bonding; the epoxy group of KH-560 can react with the sulfonyl chloride group or the hydroxyl group generated by hydrolysis; the tetrasulfide bond of Si-69 provides additional thermal stability.

[0057] Optimization of compound ratio: Grafted type: Crosslinked type = 1:0.3-1:2, adjustable according to target performance. A higher proportion of grafted type is beneficial to improving grafting efficiency; a higher proportion of crosslinked type is beneficial to improving crosslinking density.

[0058] (3) Multidimensional nano-reinforced phase

[0059] Zero-dimensional nano-silica: particle size 5-30nm, specific surface area ≥300m² / g. Surface functionalized with KH-560 to introduce epoxy groups, which can form covalent bonds with silane networks.

[0060] One-dimensional carbon nanotubes: Carboxylation or hydroxylation treatment introduces active functional groups, which can participate in cross-linking reactions and form fibrous reinforcing networks in the matrix.

[0061] Two-dimensional layered hydrogen hydroxide (LDH): Chemical composition After organic modification, it has a large aspect ratio and forms a physical barrier layer in the matrix, which improves barrier performance and thermal stability.

[0062] Synergistic effect: The combination of three-dimensional nanomaterials can achieve:

[0063] Zero-dimensional materials fill nanoscale voids, increasing cross-linking density;

[0064] One-dimensional materials form fiber networks to enhance mechanical properties and electrical / thermal conductivity;

[0065] Two-dimensional materials form a physical barrier layer, improving barrier performance and thermal stability;

[0066] The three elements work together to form a three-dimensional, through-hole nano-reinforcement network.

[0067] (4) Hyperbranched polymer modifier

[0068] Amino-terminated hyperbranched polyesters: A large number of amino groups on the periphery of the molecule can react with CSM sulfonyl chloride groups, and the amino groups can catalyze the hydrolysis and condensation of silanes.

[0069] Hydroxyl-terminated hyperbranched polyamides: hydroxyl groups can condense with silanes and participate in network construction.

[0070] Hyperbranched polysiloxanes: Containing siloxane structures, they have excellent compatibility with silane networks and can be uniformly dispersed in cross-linked networks.

[0071] Mechanism of action: The three-dimensional spherical structure of hyperbranched polymers forms physical entanglements in the cross-linked network. Numerous terminal functional groups can participate in chemical reactions, chemically bonding hyperbranched molecules into the network to form a topological structure. This structure dissipates energy through molecular chain rearrangement under external forces, significantly improving the material's toughness and creep resistance.

[0072] (5) Environmentally friendly plasticizers

[0073] Polyester-based plasticizers: high molecular weight, resistant to migration, and good compatibility with CSM.

[0074] Epoxy fatty acid methyl esters: bio-based source, the epoxy groups can participate in the reaction.

[0075] Citric acid esters: non-toxic and environmentally friendly, with good low-temperature resistance.

[0076] By abandoning traditional phthalate plasticizers, the entire system becomes environmentally friendly.

[0077] (6) Catalyst

[0078] Dibutyltin dilaurate, dibutyltin diacetate, or organobismuth catalysts. Organobismuth catalysts are environmentally friendly catalysts that meet the higher environmental protection requirements of lead-free and tin-free production.

[0079] (7) Fillers and functional additives

[0080] Fillers: calcined clay, talc powder, and mica powder, working synergistically with nano-reinforcing phases to further reduce costs and adjust performance.

[0081] Functional additives include antioxidants (such as 1010 and 168), light stabilizers (such as UV-531), antioxidants (such as RD and MB), and processing aids (such as stearic acid and polyethylene wax).

[0082] 2. Innovation in preparation process

[0083] This invention develops a process route of "stepwise grafting-gradient catalysis-programmed crosslinking" to achieve hierarchical control of the triple network structure:

[0084] Step 1: Synergistic Functionalization of Multidimensional Nano-Reinforced Phases

[0085] Three types of nanomaterials were synergistically functionalized under ultrasonic assistance. The key points were: ultrasonic dispersion to break up nanomaterial agglomeration and achieve uniform dispersion; adjusting the pH to 4-5 to promote silane hydrolysis and condensation with hydroxyl groups on the nanomaterial surface; controlling the reaction conditions to achieve monolayer grafting and avoid excessive modification leading to agglomeration; and simultaneously functionalizing the three nanomaterials under the same conditions to ensure that their surfaces have similar chemical environments, which is beneficial for subsequent dispersion and reaction.

[0086] Step 2: Predispersion of hyperbranched polymers

[0087] The hyperbranched polymer is premixed with CSM, and the hyperbranched polymer is uniformly dispersed in the CSM matrix using the high shear force of an internal mixer. The key to this step is that the highly branched structure of the hyperbranched polymer makes it easy to disperse under shear; the pre-dispersed hyperbranched polymer can serve as "active sites" for subsequent grafting reactions; and the temperature is controlled at 90-110°C to avoid premature decomposition of the initiator.

[0088] Step 3: Grafting reaction

[0089] Grafted silanes and initiators are added, and the grafting reaction is carried out under nitrogen protection. Key technical points: nitrogen protection eliminates oxygen to prevent free radicals from being terminated by oxygen; temperature is controlled at 110-130°C to match the half-life of the peroxide initiator; reaction time is 10-25 minutes to ensure the grafting rate while avoiding excessive cross-linking; the addition of some fillers can adsorb low-molecular-weight substances generated during the reaction, thereby improving grafting efficiency.

[0090] Step 4: Multidimensional Nano-Reinforced Phase Composite

[0091] After cooling to 80-100°C, functionalized nano-reinforcing phases and cross-linked silanes are added. Key technical points: The temperature is selected at 80-100°C to ensure the viscosity required for nanomaterial dispersion while avoiding premature hydrolysis of the cross-linked silanes; high-speed mixing generates strong shear force, promoting uniform dispersion of nanomaterials; the epoxy or amino groups on the surface of nanomaterials react in situ with the cross-linked silanes to form a nanomaterial-silane prepolymer structure.

[0092] Step 5: Catalysis and Final Refining

[0093] Cool to below 60°C, then add the catalyst, plasticizer, remaining filler, and functional additives. Low-temperature conditions ensure: preventing premature hydrolysis and cross-linking of silanes initiated by the catalyst; preventing plasticizer volatilization and thermal degradation; and guaranteeing processing safety.

[0094] Step 6: Molding and Process Crosslinking

[0095] A three-stage programmed crosslinking process is adopted to achieve hierarchical control of the crosslinking process:

[0096] The first stage (80-90°C, RH 60-70%, 4-8h): Under low temperature and high humidity conditions, the main goal is to achieve slow cross-linking on the surface of the product. During this stage, water molecules diffuse from the surface inward, and the surface silanes begin to hydrolyze and condense, forming a dense surface layer to prevent subsequent internal moisture loss.

[0097] The second stage (100-110°C, RH 80-90%, 8-16h): Under medium temperature and high humidity conditions, water molecules fully penetrate into the interior of the product, catalyst activity is enhanced, and silane undergoes extensive hydrolysis and condensation to form a bulk cross-linked network. This stage also promotes the chemical bonding between the functional groups on the surface of the nanomaterial and the silane network.

[0098] The third stage (120-130°C, drying, 2-4 hours): Under high-temperature drying conditions, the residual silanol is further condensed, byproducts (such as water and alcohol) generated during the crosslinking process are eliminated, and the degree of perfection of the crosslinking network is improved. At the same time, this stage promotes the topological rearrangement of hyperbranched polymers in the crosslinking network, forming a stable topological entanglement structure.

[0099] The innovation of the three-stage crosslinking process lies in:

[0100] 1. Hierarchical control: Spatial and temporal control of the crosslinking process is achieved through programmed control of temperature and humidity;

[0101] 2. Uniformity inside and out: Avoids the "burnt outside and tender inside" phenomenon caused by the traditional one-step cross-linking method, ensuring uniform cross-linking inside and outside of thick products;

[0102] 3. Network Improvement: Gradient heating promotes full condensation of silanols and improves the degree of cross-linking network perfection;

[0103] 4. Structural optimization: The third-stage heat treatment promotes topological rearrangement of the hyperbranched polymer and optimizes the network structure.

[0104] Compared with the prior art, the present invention has the following significant advantages:

[0105] (1) Ultra-high heat resistance

[0106] The constructed -Si-O-Si crosslinked network has high bond energy, the thermal shielding effect of the nano-reinforced phase, and the thermal stabilizing effect of the hyperbranched polymer, enabling the composite material to withstand long-term use temperatures up to 150℃ and short-term heat resistance up to 180℃, which is two heat resistance grades higher than the traditional CSM (125℃). After hot air aging at 150℃ for 30 days, the tensile strength retention rate is ≥85%, and the elongation at break retention rate is ≥70%.

[0107] (2) Excellent resistance to chemical media

[0108] The dense structure of the physical barrier layer and chemical cross-linked network formed by the multidimensional nano-reinforced phase significantly improves the material's barrier performance against various chemical media.

[0109] ASTM #3 oil volume change rate (150℃×70h) ≤8%;

[0110] The volume change rate of a 20% NaOH solution (100℃×168h) is ≤5%.

[0111] The volume change rate of concentrated sulfuric acid (50%, 80℃×72h) is ≤12%;

[0112] The volume change rate of fuel oil C (room temperature × 168h) is ≤15%.

[0113] (3) Extremely low compression set

[0114] The synergistic effect of the triple network and the topological entanglement of the hyperbranched polymer give the material excellent resistance to stress relaxation under high-temperature compression conditions:

[0115] 100℃×24h, compression 25%: compression set ≤12%;

[0116] 150℃×70h, compression 25%: compression set ≤25%;

[0117] 200℃×24h, compression 25%: compression set ≤40% (short-term extreme conditions).

[0118] (4) Excellent electrical insulation performance

[0119] The pure cross-linking system and uniform dispersion of nanomaterials endow the material with excellent electrical insulation properties:

[0120] Volume resistivity: ≥1×10^16 Ω·cm;

[0121] Dielectric strength: ≥25 kV / mm;

[0122] Dielectric constant (1kHz): 3.0-3.5;

[0123] Dielectric loss factor (1kHz): ≤0.01.

[0124] (5) Comprehensive mechanical properties

[0125] Tensile strength: 18-28 MPa (adjustable);

[0126] Elongation at break: 350-500%;

[0127] Tear strength: 45-65 kN / m;

[0128] Resilience: 45-55%;

[0129] Akron wear: ≤0.15 cm³ / 1.61km.

[0130] (6) Adaptability to extreme environments

[0131] Radiation resistance: After irradiation with gamma rays (total dose of 500 kGy), the mechanical properties are retained at a rate of ≥80%;

[0132] Resistant to high and low temperature cycling: 100 cycles from -60℃ to 150℃, no cracks or delamination;

[0133] High pressure resistance: Performance retention rate ≥90% in simulated deep-sea environment (60 MPa, 30 days);

[0134] Salt spray resistance: After 1000 hours of 5% NaCl salt spray test, there is no change in appearance and the performance retention rate is ≥95%.

[0135] (7) Environmental protection and safety

[0136] Completely eliminate toxic heavy metals such as lead and cadmium;

[0137] Free of phthalate plasticizers;

[0138] It complies with international environmental regulations such as RoHS, REACH, and IEC 61249-2-21;

[0139] The use of bio-based plasticizers and some bio-based hyperbranched polymers has reduced the carbon footprint.

[0140] (8) Strong process designability

[0141] By adjusting the ratio of compounded silanes, the proportion of nanomaterials, the type and amount of hyperbranched polymers, and the parameters of the programmed crosslinking process, the material properties can be precisely controlled to meet the customized needs of different application fields.

[0142] The present invention will be further described below with reference to specific embodiments, but the scope of protection of the present invention is not limited thereto.

[0143] Examples 1-5 and Comparative Examples 1-3

[0144] The formula is shown in Table 1 (unit: parts by weight).

[0145] Comparative Example 1: Traditional lead oxide sulfidation system (CSM + PbO + pentaerythritol), without silane crosslinking and without nano-reinforcement.

[0146] Comparative Example 2: A single silane crosslinking system (grafted silane only), without nano-reinforcement and without hyperbranched polymers.

[0147] Comparative Example 3: Silane crosslinking + conventional nano-SiO2 (unfunctionalized), without hyperbranched polymer.

[0148] Examples 1-5: The multidimensional enhanced silane crosslinking system of the present invention, with changes in the nanomaterial ratio, hyperbranched polymer type and silane compounding ratio.

[0149] Table 1: Formula Table

[0150]

[0151] Preparation process:

[0152] Comparative Example 1:

[0153] CSM, lead oxide, pentaerythritol, calcined clay, antioxidants, anti-aging agents and stearic acid are mixed evenly on a two-roll mill and vulcanized on a 160°C flat vulcanizing machine.

[0154] Comparative Example 2:

[0155] (1) Grafting reaction: CSM, calcined clay, vinyltrimethoxysilane, and dicumyl peroxide (DCP) were reacted in a mixer at 115°C for 10 minutes;

[0156] (2) Cool down to 50°C, add the remaining calcined clay, epoxy fatty acid methyl ester, dibutyltin dilaurate, antioxidant, anti-aging agent and stearic acid, mix well and extrude into tablets;

[0157] (3) Vulcanization: 170℃ × t90;

[0158] (4) Post-treatment: 90℃×85%RH×12h.

[0159] Comparative Example 3: Same as Comparative Example 2, but ordinary nano-SiO2 (unfunctionalized) was added in the first step.

[0160] Examples 1-5:

[0161] (1) Synergistic functionalization of multidimensional nano-reinforced phase: According to the formula ratio, nano-SiO2, carbon nanotubes and LDH are dispersed in ethanol / water (80 / 20 v / v) mixed solvent, KH-560 (5% relative to the total mass of nanomaterials) is added, pH is adjusted to 4.5 with acetic acid, and ultrasonic reaction is carried out at 70℃ (300W, 30kHz) for 3 hours. After filtration and washing with ethanol 3 times, vacuum drying is carried out at 60℃ for 12 hours.

[0162] (2) Pre-dispersion of hyperbranched polymer: In a mixer, CSM and hyperbranched polymer are premixed at 100°C for 8 minutes and then discharged.

[0163] (3) Grafting reaction: Add the pre-dispersed masterbatch to the internal mixer, heat it to 115°C, add half of the calcined clay, grafted silane and DCP, and react for 12 minutes under nitrogen protection.

[0164] (4) Multidimensional nano-reinforced phase composite: Cool down to 90℃, add functionalized nano-reinforced phase and cross-linked silane (KH-560), and mix at high speed for 12 minutes.

[0165] (5) Catalysis and final refining: Remove the glue, cool to below 50°C, add the remaining calcined clay, epoxy fatty acid methyl ester, dibutyltin dilaurate, antioxidant, anti-aging agent and stearic acid to the open mill, pass through 6 times, and then produce sheets.

[0166] (6) Molding and cross-linking: The rubber compound is pre-molded in a 170℃ flat vulcanizing machine for 5 minutes (not fully cross-linked, only set); then a three-stage cross-linking process is performed:

[0167] Phase 1: 85℃ × RH 65% × 6h;

[0168] Second stage: 105℃×RH85%×12h;

[0169] Third stage: 125℃ × drying × 3h.

[0170] Performance testing:

[0171] The vulcanizates obtained from each embodiment and comparative example were tested according to relevant national and international standards, and the results are shown in Tables 2 and 3.

[0172] Table 2: Basic Physical and Mechanical Properties

[0173] Table 3: Heat Aging Resistance, Compression Set and Electrical Properties

[0174]

[0175] Table 4: Chemical resistance properties

[0176]

[0177] Results analysis:

[0178] (1) The synergistic enhancement effect of the triple network is significant.

[0179] As shown in Table 2, the mechanical properties of Examples 1-5 of this invention are comprehensively superior to those of the comparative examples. Example 5 (zero-dimensional + one-dimensional + two-dimensional nanocomposite, silane composite, double hyperbranched polymer) exhibits the best overall performance, with a tensile strength of 26.8 MPa, representing a 103% improvement over Comparative Example 1 (conventional PbO vulcanization) and an 81% improvement over Comparative Example 2 (single silane crosslinking). Its tear strength reaches 62 kN / m, a 121% improvement over Comparative Example 1. This indicates that the synergistic effect of the "chemical grafting-nano reinforcement-topological entanglement" triple network produces a significant reinforcing effect.

[0180] (2) The key role of dimensional composite of nanomaterials

[0181] Comparing Example 1 (nano SiO2 only) with Example 2 (nano SiO2 + carbon nanotubes): Example 2 showed a 20% increase in tensile strength, a 21% increase in tear strength, and a 33% increase in abrasion resistance. The addition of one-dimensional carbon nanotubes formed a fiber-reinforced network, complementing the point reinforcement of zero-dimensional nanoparticles. Comparing Example 2 with Example 3 (with two-dimensional LDH): Example 3 maintained high strength while showing an increased elongation at break, indicating that the addition of two-dimensional materials improved the toughness of the material.

[0182] (3) The necessity of functionalizing nanomaterials

[0183] Comparing Example 3 with Comparative Example 3: Comparative Example 3 used unfunctionalized nano-SiO2. Although the formulation was similar, the tensile strength was only 13.5 MPa, far lower than the 24.2 MPa of Example 3. This indicates that surface functionalization of nanomaterials is a prerequisite for their reinforcing effect. Unfunctionalized nanomaterials have weak interfacial bonding with the matrix and cannot effectively participate in the construction of cross-linked networks.

[0184] (4) Topological entanglement effect of hyperbranched polymers

[0185] Comparing Example 1 and Example 4: In Example 4, hyperbranched polysiloxane was used to replace part of the terminal amino hyperbranched polyester, resulting in a slight increase in tensile strength (22.6 → 23.6 MPa), but a significant improvement in compression set (20% → 18%). The three-dimensional spherical structure of the hyperbranched polymer forms topological entanglements in the crosslinked network, enhancing the network's toughness and creep resistance.

[0186] (5) Achieving ultra-high heat resistance

[0187] Table 3 shows that under harsh aging conditions of 150℃ for 720 hours (30 days), Example 5 maintained 85% of its tensile strength and 80% of its elongation at break, significantly better than Comparative Example 1's 42% and 28%, respectively. This indicates that the triple network structure possesses excellent resistance to thermo-oxidative aging. Example 5 exhibited only 35% compression set at 175℃ for 24 hours, while Comparative Example 1 reached 92%, demonstrating that the material of this invention can withstand short-term high temperatures of 175℃ and long-term service temperatures up to 150℃, representing a two-level improvement in heat resistance compared to traditional CSM.

[0188] (6) Excellent electrical insulation performance

[0189] Example 5 achieved a volume resistivity of 1.5 × 10^16 Ω·cm, nearly 20 times higher than Comparative Example 1 and 6 times higher than Comparative Example 2. This is attributed to: a pure cross-linking system that avoids conductive impurities such as lead salts; uniform dispersion of nanomaterials that reduces local electric field concentration; and a well-developed cross-linking network that reduces the migration of polar groups.

[0190] (7) Excellent resistance to chemical media

[0191] Table 4 shows that the volume change rate of Example 5 in various harsh chemical media was significantly lower than that of the comparative example. The physical barrier layer and dense chemical cross-linking network formed by the multidimensional nano-reinforced phase effectively prevented the penetration and diffusion of chemical media.

[0192] (8) Microscopic mechanism verification of triple network structure

[0193] As shown in Table 3, the crosslinking density of Example 5 reached 5.5 × 10⁻⁶. 4 The crosslinking density was mol / cm³, a 120% increase compared to Comparative Example 2 (single silane crosslinking). However, the increased crosslinking density was not the only reason for the improved performance—Example 3 had a higher crosslinking density (4.8) than Example 1 (4.2), but slightly lower tensile strength (24.2 vs 21.5), indicating that the addition of nanomaterials and hyperbranched polymers optimized the network structure, rather than simply increasing the number of crosslinking points. Dynamic mechanical analysis (DMA) showed that the tanδ peak value of Example 5 (0.62) was significantly lower than that of Comparative Example 2 (0.85), indicating that the triple network effectively restricted the segmental movement of molecular chains and enhanced the overall integrity of the network.

[0194] Application examples

[0195] Application Example 1: Insulation material for Class 1E K1 cables used in nuclear power plants

[0196] The cable insulation layer prepared using the formulation of Example 5 was subjected to a simulated LOCA (Loss of Coolant Accident) test according to the IEEE 383-2015 standard:

[0197] Irradiation aging: Total gamma ray irradiation dose 500 kGy;

[0198] Thermal aging: 138℃×300h;

[0199] Steam exposure: Exposure to saturated steam (170℃) for 72 hours;

[0200] Chemical spraying: Spray with alkaline boric acid solution for 30 days.

[0201] After the test, the material retained 82% of its tensile strength, 75% of its elongation at break, and >1×10^14Ω·cm of volume resistivity, meeting the requirements of Class 1E K1 cables for nuclear power plants.

[0202] Application Example 2: Seals for Deep-Sea Oil Extraction Equipment

[0203] The O-rings prepared using the formulation in Example 2 were installed in a simulated deep-sea production tree device for comprehensive operating condition testing.

[0204] hydrostatic pressure: 60 MPa;

[0205] Temperature: 4-120℃ (cycled);

[0206] Medium: Crude oil + brine + CO2 + H2S mixed medium;

[0207] Time: 180 days.

[0208] After the test, the sealing ring showed no leakage, bulging, or cracks, and the permanent compression deformation was less than 20%, maintaining good sealing performance and meeting the requirements of NORSOK M-710 standard.

[0209] Application Example 3: Sealing components for high-voltage connection systems in new energy vehicles

[0210] The rectangular sealing ring prepared using the formulation of Example 5 was used in an 800V high-voltage connector and tested according to LV 215-1 standard:

[0211] Withstand voltage: 8 kV AC, no breakdown in 1 minute;

[0212] Insulation resistance: >1×10^12 Ω;

[0213] Thermal cycling: -40℃ to 150℃, 1000 cycles, no leakage;

[0214] Electrochemical corrosion resistance: No electrochemical corrosion phenomenon was observed when a DC voltage was applied to a NaCl solution for 500 hours.

[0215] The test results meet the highest level requirements of Volkswagen LV 215-1.

[0216] Application Example 4: Aerospace Hydraulic Seals

[0217] The hydraulic seals prepared using the formulation of Example 3 were subjected to compatibility testing with aviation hydraulic oil (Skydrol LD-4) according to AS4059 standard:

[0218] Soaking conditions: 135℃ × 1000h;

[0219] Volume change rate: +6.5%;

[0220] Hardness change: -2 Shore A;

[0221] Tensile strength retention rate: 92%;

[0222] Compression set (135℃×24h): 18%.

[0223] It meets the requirements of the aerospace seal standard HB 7483-2014 and can be used in aircraft hydraulic systems.

[0224] Application Example 5: Sealing Elements for Geothermal Exploration Equipment

[0225] The drilling equipment seal prepared using the formulation of Example 4 was used to simulate the working conditions of a geothermal well.

[0226] Medium: Geothermal water (containing H2S, CO2, SiO2, etc.);

[0227] Temperature: 200℃ (can reach 250℃ for short periods);

[0228] Pressure: 35 MPa;

[0229] Time: 720 hours (continuous).

[0230] After the test, the seals were intact, with no swelling, softening, or hardening cracks, and maintained good sealing performance, meeting the stringent requirements of geothermal exploration equipment for high temperature resistance and corrosion resistance of materials.

[0231] Technical Distinction from Existing Patent (CN107851489A, entitled Insulated Wires and Cables)

[0232] To clarify the innovativeness of this invention, a systematic comparison is now made between this invention and prior art document CN107851489A:

[0233]

[0234] The implementation of this invention will strongly promote the technological progress of special rubber materials and meet the urgent needs of major national projects and strategic emerging industries for high-performance basic materials.

[0235] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A multidimensional reinforced silane crosslinked chlorosulfonated polyethylene nanocomposite material, characterized in that: By weight, it includes the following components: Chlorosulfonated polyethylene: 100 parts; Compound silane crosslinking system: 3-15 parts; Multidimensional nano-reinforcing phase: 5-30 parts; Hyperbranched polymer modifier: 1-8 parts; Environmentally friendly plasticizer: 5-20 parts; Catalyst: 0.1-2 parts; Filler: 10-60 parts; Functional additives: 2-8 parts.

2. The multidimensional reinforced silane crosslinked chlorosulfonated polyethylene nanocomposite material according to claim 1, characterized in that: The compounded silane crosslinking system is composed of grafted silane and crosslinked silane in a mass ratio of 1:0.3-1:2; wherein the grafted silane is at least one of vinyltrimethoxysilane, vinyltriethoxysilane or γ-methacryloxypropyltrimethoxysilane; and the crosslinked silane is at least one of γ-aminopropyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane or bis-[γ-(triethoxysilane)propyl]tetrasulfide.

3. The multidimensional reinforced silane crosslinked chlorosulfonated polyethylene nanocomposite material according to claim 1, characterized in that: The multidimensional nano-reinforcing phase is a multi-component composite system of functionalized zero-dimensional nanoparticles, one-dimensional nanomaterials, and two-dimensional nanomaterials; the zero-dimensional nanoparticles are nano-silica with surface-grafted amino or epoxy groups, with a particle size of 5-30 nm; the one-dimensional nanomaterials are carboxylated or hydroxylated carbon nanotubes with a diameter of 10-30 nm and a length of 1-20 μm; the two-dimensional nanomaterials are layered double hydroxides or modified montmorillonite, with a sheet thickness of 1-3 nm and an aspect ratio >100; the mass ratio of the three is zero-dimensional: one-dimensional: two-dimensional = 1:0.1-0.5:0.2-1.

4. A multidimensional reinforced silane crosslinked chlorosulfonated polyethylene nanocomposite material according to claim 1 or 3, characterized in that: The hyperbranched polymer modifier is at least one of amino-terminated hyperbranched polyester, hydroxyl-terminated hyperbranched polyamide, or hyperbranched polysiloxane, with a number-average molecular weight of 2000-20000 and a branching degree ≥0.

6.

5. A multidimensional reinforced silane crosslinked chlorosulfonated polyethylene nanocomposite material according to claim 1 or 3, characterized in that: The environmentally friendly plasticizer is at least one of polyester plasticizer, epoxy fatty acid methyl ester or citrate plasticizer; the catalyst is at least one of dibutyltin dilaurate, dibutyltin diacetate or organic bismuth catalyst.

6. A multidimensional reinforced silane crosslinked chlorosulfonated polyethylene nanocomposite material according to claim 1 or 3, characterized in that: The filler is at least one of calcined clay, talc powder, and mica powder; the functional additives include antioxidants, light stabilizers, anti-aging agents, and processing aids.

7. A method for preparing the multidimensional reinforced silane crosslinked chlorosulfonated polyethylene nanocomposite material as described in any one of claims 1-6, characterized in that, Includes the following steps: (1) Synergistic functionalization of multidimensional nano-reinforced phase: nano-silica, carbon nanotubes and layered double hydroxides are dispersed in an ethanol / water mixed solvent according to the ratio, silane coupling agent KH-560 is added, the pH is adjusted to 4-5, and the reaction is carried out with ultrasonic assistance at 60-80°C for 2-4 hours. After filtration, washing and vacuum drying, synergistic functionalized multidimensional nano-reinforced phase is obtained. (2) Pre-dispersion of hyperbranched polymer: Chlorosulfonated polyethylene and hyperbranched polymer modifier are pre-mixed in an internal mixer at 90-110°C for 5-10 minutes to uniformly disperse the hyperbranched polymer in the CSM matrix and form a pre-dispersion masterbatch; (3) Grafting reaction: Add some filler, grafted silane and initiator to the pre-dispersed masterbatch in step (2), heat to 110-130°C, and react for 10-25 minutes under nitrogen protection to graft the grafted silane onto the CSM molecular chain to obtain grafted masterbatch. (4) Multidimensional nano-reinforced phase composite: Cool the grafted masterbatch from step (3) to 80-100°C, add the synergistically functionalized multidimensional nano-reinforced phase and cross-linked silane, and mix at high speed for 8-15 minutes to make the nanomaterials uniformly dispersed and react in situ. (5) Catalysis and final mixing: Cool the mixture from step (4) to below 60°C, add catalyst, environmentally friendly plasticizer, remaining filler and functional additives, and mix evenly on a two-roll mill to produce sheets; (6) Molding and crosslinking process: The final rubber is made into products by extrusion, calendering or compression molding, and a three-stage crosslinking process is adopted: first, it is treated at 80-90°C and 60-70% relative humidity for 4-8 hours to complete surface crosslinking; then, it is treated at 100-110°C and 80-90% relative humidity for 8-16 hours to complete bulk crosslinking; finally, it is treated at 120-130°C in a dry environment for 2-4 hours to complete curing and residual silanol condensation.

8. The method for producing a multidimensional reinforced silane crosslinked chlorosulfonated polyethylene nanocomposite material according to claim 7, characterized in that: In step (1), the ultrasonic power of the ultrasonic-assisted reaction is 200-500W and the frequency is 20-40kHz. In step (6), the temperature, humidity and time of each stage of the three-stage crosslinking process can be optimized and adjusted according to the thickness of the product to meet the matching relationship between the thickness of the product and the uniformity of crosslinking.

9. The method for a multidimensional reinforced silane crosslinked chlorosulfonated polyethylene nanocomposite material according to claim 7, characterized in that: The initiator is at least one of dicumyl peroxide, 1,4-di-tert-butylperoxypropylbenzene, or 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, and its addition amount is 0.5-2.5% of the mass of chlorosulfonated polyethylene.

10. The application of the multidimensional reinforced silane crosslinked chlorosulfonated polyethylene nanocomposite material according to any one of claims 1-6 in the preparation of nuclear power cable insulation layers, deep-sea oil extraction equipment seals, new energy vehicle high-voltage connection systems, aerospace hydraulic seals, or geothermal exploration equipment sealing elements.

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