A liquid ethylene propylene diene rubber / filler highly dispersed material, rubber material and preparation method and application thereof
By preparing modified fillers containing -SH bonds and crosslinking them with liquid EPDM rubber, the problem of uneven mixing between liquid EPDM rubber and fillers was solved, thus improving the performance of the sealing material.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- ZHONGXIN SUPPLY CHAIN MANAGEMENT (HAINAN) CO LTD
- Filing Date
- 2026-04-03
- Publication Date
- 2026-06-09
Smart Images
Figure CN122167899A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of rubber sealing ring materials technology, and in particular to a highly dispersed liquid EPDM rubber / filler material, the rubber material, its preparation method, and its application. Background Technology
[0002] Ethylene propylene diene monomer (EPDM) rubber, due to its excellent weather resistance, ozone resistance, heat resistance, and chemical stability, has become one of the key materials for manufacturing sealing rings, and is widely used in automotive, aerospace, construction, and liquid cooling systems. With the increasing demands for sealing performance in engineering applications, its material preparation technology is also constantly innovating and developing. In practical industrial applications, to improve the mechanical properties of the material and reduce production costs, fillers such as silica, carbon black, and calcium carbonate need to be added to the rubber material. However, because EPDM rubber is composed of hydrocarbons and has extremely high bulk viscosity, uneven mixing with fillers during processing and insufficient filler content affect the performance of the rubber material, making it difficult to improve the physical and mechanical properties and low-temperature resistance of the sealing material.
[0003] Liquid EPDM possesses the characteristics of solid EPDM while exhibiting good flowability. It can be used as a plasticizer for solid EPDM to improve processing performance and enhance filler dispersibility. However, currently, liquid EPDM is mainly produced by Lion Chemicals in the United States. While it boasts advantages such as narrow molecular weight distribution and stable product quality, its high molecular weight results in poor flowability, and it remains semi-solid at room temperature, making direct application difficult. This liquid EPDM requires heating to 100℃ before use (at which point the viscosity is 102,000 cps), leading to a narrow operating window and poor processing performance. Although organic solvents can be used to dilute and reduce viscosity, this introduces volatile organic compounds (VOCs), posing a threat to the environment and operator health, increasing costs, and extending the construction period. Therefore, developing low-viscosity, room-temperature processable liquid EPDM is of significant research value. Zhang et al. [China Synth. Rubber Ind. 43 (2020) 424] successfully prepared a polymer with a structure similar to EPDM by synthesizing liquid rubber and further hydrogenating it using isoprene as a raw material. However, this method is limited to the synthesis of binary liquid ethylene-propylene rubber with an ethylene to propylene unit ratio of 1:1. Currently, liquid ethylene-propylene rubber mainly relies on pyrolysis for preparation, i.e., obtaining low molecular weight products by thermally or catalytically pyrolyzing high molecular weight ethylene-propylene rubber. Although pyrolysis can prepare binary ethylene-propylene rubber, the molecular weight of the product is difficult to control precisely, and the molecular weight distribution is relatively wide. It is worth noting that the third monomer contained in ternary ethylene-propylene rubber—such as ethyleneide norbornene (ENB), dicyclopentadiene (DCPD), and 1,4-hexadiene—are all unsaturated compounds, which are crucial for achieving rapid vulcanization. However, during the pyrolysis process, these key carbon-carbon double bonds are easily destroyed, making it impossible to obtain liquid ternary ethylene-propylene rubber by this method. Wang et al. [Polymer 303 (2024)127138] first reported the research on the synthesis of liquid ternary ethylene-propylene rubber using vanadium-based catalysts. This study successfully prepared liquid ethylene propylene diene monomer (EPDM) rubber with molecular weights ranging from 4530 to 10180 (PDI = 3.5–7.1) using ethylene, propylene, and ENB as raw materials. However, the use of a large amount of chlorine-containing compounds during the reaction triggered numerous side reactions, leading to damage to the ENB double bonds. Although the resulting product exhibits low-temperature crosslinking properties, its reaction controllability is poor.
[0004] Therefore, it is necessary to seek a suitable process for preparing liquid EPDM rubber, and to seek a highly dispersed EPDM rubber / filler material to increase the filler content and dispersion, improve the high viscosity EPDM rubber system, thereby improving the physical and mechanical properties and low temperature resistance of vulcanized rubber, and preparing high-performance rubber sealing materials. Summary of the Invention
[0005] In view of this, the present invention proposes a highly dispersed liquid EPDM rubber / filler material, a rubber material, its preparation method, and its application. The technical solution of this invention is implemented as follows: A method for preparing a highly dispersed liquid EPDM rubber / filler material includes the following steps: (1) Butadiene, initiator, solvent and regulator are stirred once, the reaction is terminated by adding a terminator, then washed and dried to obtain liquid polybutadiene, epoxidant is added to react to obtain liquid polymer containing epoxy groups, diethanolamine is added to stir twice to obtain liquid polymer containing hydroxyl groups, and finally hydrogenation reaction is carried out to obtain hydrogenated liquid polybutadiene containing hydroxyl groups. (2) Hydrogenated liquid polybutadiene containing hydroxyl groups and filler are stirred three times, filtered, mercaptopropionic acid and catalyst are added and stirred four times, and then liquid EPDM rubber is added and mixed to obtain liquid EPDM rubber / filler high dispersion material.
[0006] Furthermore, the synthesis route of the liquid EPDM rubber / filler highly dispersed material is as follows: , in, The filler is represented by x, x, and z, which all represent the degree of polymerization, where x ≥ 0, x ≥ 0, and z ≥ 0.
[0007] Furthermore, in step (1), The initiator is butyllithium; the solvent is n-hexane; the modifier is tetrahydrofuran; the terminator is acidified ethanol; the epoxidizing agent is one or more of benzoic acid peroxide, formic acid, and hydrogen peroxide mixed solution; in the formic acid and hydrogen peroxide mixed solution, the volume ratio of formic acid to hydrogen peroxide is 1:2~4; the formic acid concentration is 75~80% w / w; the hydrogen peroxide concentration is 30~35% w / w; The acidified ethanol is selected from hydrochloric acid-ethanol solution or acetic acid-ethanol solution; the hydrochloric acid-ethanol solution comprises anhydrous ethanol and concentrated hydrochloric acid in a volume ratio of 8~9:1~2; the concentrated hydrochloric acid has a mass fraction of 36%~38%; the acetic acid-ethanol solution comprises anhydrous ethanol and glacial acetic acid in a volume ratio of 90~95:5~10. The mass ratio of butadiene, initiator, epoxidant, and diethanolamine is 5~9:1:2~15:1~9; The volume ratio of the solvent, regulator, and terminator is 80:2~2.5:20~50; The mass-to-volume ratio of butadiene to solvent is 6-10g:80ml; The molecular weight of the liquid polybutadiene is 200-700; Furthermore, the temperature of the first stirring reaction is 25~50℃ and the time is 30~90min.
[0008] Furthermore, the temperature of the first stirring reaction is 30~45℃ and the time is 35~80min.
[0009] Furthermore, the reaction temperature for adding the epoxidizing agent is 25~45℃ and the reaction time is 2~5h.
[0010] Furthermore, the reaction temperature for adding the epoxidizing agent is 25~40℃ and the reaction time is 2.5~4.5h.
[0011] Furthermore, the temperature of the secondary stirring reaction is 45~65℃ and the time is 1~4h.
[0012] Furthermore, the temperature of the secondary stirring reaction is 50~60℃ and the time is 1.5~3.5h.
[0013] Furthermore, the catalyst for the hydrogenation reaction is a Pt / C catalyst with a hydrogenation degree ≥99% and a reaction temperature of 50~120℃.
[0014] Furthermore, the catalyst for the hydrogenation reaction is a Pt / C catalyst with a hydrogenation degree ≥99% and a reaction temperature of 60~115℃.
[0015] Furthermore, the mass fraction of platinum in the Pt / C catalyst is 5% to 10%.
[0016] Furthermore, the Pt / C catalyst contains 5% platinum by mass.
[0017] Furthermore, in step (2), The filler is selected from one or more of carbon black, graphene oxide, and montmorillonite; The catalyst is selected from one or more of p-toluenesulfonic acid, phosphotungstic acid, silicotungstic acid, and acidic molecular sieves.
[0018] Furthermore, the acidic molecules are selected from ZSM-5, SPAO-7, MCM-41, mordenite, aluminosilicate molecular sieves, etc.
[0019] Furthermore, the mass ratio of the hydroxyl-containing hydrogenated liquid polybutadiene, filler, mercaptopropionic acid, and catalyst is 5~25:100:5~35:0.05~0.8.
[0020] Furthermore, the mass ratio of the hydroxyl-containing hydrogenated liquid polybutadiene, filler, mercaptopropionic acid, and catalyst is 10~15:100:8~15:0.2~0.3.
[0021] Furthermore, the mass ratio of the liquid EPDM rubber to the filler is 0.2~5:1.
[0022] Furthermore, the mass ratio of the liquid EPDM rubber to the filler is 0.5~4.5:1.
[0023] Furthermore, the three stirring reactions are carried out at a temperature of 120~150℃ for 8~15h.
[0024] Furthermore, the three stirring reactions are carried out at a temperature of 120~145℃ for a time of 9~13h.
[0025] Furthermore, the temperature of the four stirring reactions is 90~130℃ and the time is 8~15h.
[0026] Furthermore, the temperature of the four stirring reactions is 95~125℃ and the time is 9~15h.
[0027] Furthermore, the mixing time is 30-90 minutes.
[0028] Furthermore, the mixing time is 35-85 minutes.
[0029] Furthermore, the synthesis route diagram of the liquid EPDM rubber is as follows: , Where a, b, c, z all represent the degree of polymerization, a≥0, b≥0, c≥0, d≥0; R1 is H or methyl.
[0030] Furthermore, the liquid EPDM rubber has a molecular weight of 2000-20000 and an ethylene content of 45-65%.
[0031] Furthermore, the liquid EPDM rubber has a molecular weight of 2500~18000 and an ethylene content of 45~63%.
[0032] Furthermore, the synthesis process of the liquid EPDM rubber is as follows: solvent, main catalyst, co-catalyst, third monomer and activator are added to the reaction vessel, mixed gas is introduced to carry out the reaction, quenching is performed, and the solvent is removed to obtain liquid EPDM rubber.
[0033] Furthermore, the solvent is n-hexane; the main catalyst is vanadium oxychloride; the co-catalyst is alkylaluminum; the third monomer is selected from one or more of 1,4-hexadiene and 5-methyl-1,5-hexadiene; the activator is selected from ethyl trichloroacetate; and the mixed gas includes ethylene, propylene, and hydrogen in a volume ratio of 1~2:2~3:0.09~0.3.
[0034] Furthermore, the Al / V ratio in the co-catalyst and the main catalyst is 10~40.
[0035] Furthermore, the Al / V ratio in the co-catalyst and the main catalyst is 15~35.
[0036] Furthermore, the reaction temperature is 40~50℃, the pressure is 0.2~0.5MPa, and the time is 40~120min.
[0037] Furthermore, the reaction temperature is 42~48℃, the pressure is 0.3~0.5MPa, and the time is 45~115min.
[0038] Furthermore, the ratio of the main catalyst, co-catalyst, third monomer, and activator is 0.3~0.6g:4~6g:1ml; the volume ratio of the third monomer, activator, and solvent is 1:3~6:200~350.
[0039] A rubber material comprising the aforementioned liquid EPDM rubber / filler highly dispersed material.
[0040] Furthermore, the rubber material comprises the following raw materials in parts by weight: 90-110 parts of solid EPDM rubber, 0-10 parts of liquid EPDM rubber, 30-90 parts of liquid EPDM rubber / filler high dispersion material, 2-8 parts of crosslinking agent, and 1-5 parts of additives.
[0041] Furthermore, the rubber material comprises the following raw materials in parts by weight: 100 parts of solid EPDM rubber, 5-10 parts of liquid EPDM rubber, 70-90 parts of liquid EPDM rubber / filler high dispersion material, 6-8 parts of crosslinking agent, and 1-5 parts of additives.
[0042] Furthermore, the solid EPDM rubber is EPDM plastic granules, CAS number 25038-36-2.
[0043] Furthermore, the crosslinking agent is selected from one or more of dicumyl peroxide or sulfur; the auxiliary agent is selected from one or more of peroxide, stearic acid, antioxidant, etc.
[0044] Furthermore, the peroxide is selected from one or more of di-tert-butyl peroxide, dicumyl peroxide, methyl ethyl ketone peroxide, cyclohexanone peroxide, tert-butyl hydroperoxide, and cumyl hydroperoxide.
[0045] Furthermore, the antioxidant is selected from one or more of antioxidants 4010NA, 4020, RD, AW, 264, and 2246.
[0046] The preparation method of rubber material includes the following steps: taking solid EPDM rubber, liquid EPDM rubber, liquid EPDM rubber / filler highly dispersed material for mixing, and then adding crosslinking agent and additives for mixing and molding.
[0047] Furthermore, the reaction is carried out at 130~160°C for 30~90 minutes.
[0048] Furthermore, the reaction is carried out at 135~155°C for 35~85 minutes.
[0049] Application of rubber materials as sealing materials in liquefied gas marine dome seals.
[0050] Compared with the prior art, the beneficial effects of the present invention are: First, this invention achieves chemical bonding between the filler and the modifier through the reaction of functional groups, preparing a modified filler containing -SH bonds. Then, based on the low viscosity of liquid EPDM, the modified filler is dispersed in liquid EPDM to obtain a highly dispersed material. Finally, it is added to solid EPDM, and the formulation is adjusted to prepare a sealing ring material. During processing and mixing, the modifier and liquid EPDM are combined through the reaction of -SH with the carbon-carbon double bonds in EPDM. Simultaneously, the liquid EPDM and solid EPDM crosslink, inhibiting problems such as small molecule migration and blooming. This invention can improve the dispersibility of fillers in solid EPDM, increase the filler content and dispersion, improve the processing technology of high-viscosity EPDM systems, improve the physical and mechanical properties and low-temperature resistance of vulcanized rubber, and prepare high-performance rubber sealing materials. Attached Figure Description
[0051] Figure 1 The NMR spectrum of the liquid EPDM rubber prepared in Example 1 is shown. Figure 2 The NMR spectrum of the hydroxyl-containing hydrogenated liquid polybutadiene prepared in Example 1 is shown below. Figure 3 The image shows the liquid EPDM rubber product obtained in Example 1. Figure 4 A diagram of the sealing material product obtained in Example 1; Figure 5 This is a schematic diagram of the sealing material prepared in Example 1 installed on the dome of a liquefied gas ship. Detailed Implementation
[0052] To better understand the technical content of this invention, specific embodiments are provided below to further illustrate the invention.
[0053] Unless otherwise specified, the experimental methods used in the embodiments of this invention are all conventional methods.
[0054] Unless otherwise specified, all materials and reagents used in the embodiments of this invention are commercially available.
[0055] The synthesis route diagram for liquid EPDM rubber is as follows: , Where a, b, c, z all represent the degree of polymerization, a≥0, b≥0, c≥0, d≥0; R1 is H or methyl.
[0056] The synthesis route for highly dispersed liquid EPDM rubber / filler materials is as follows: , in, The filler is represented by x, x, and z, which all represent the degree of polymerization, where x ≥ 0, x ≥ 0, and z ≥ 0.
[0057] The solid EPDM rubber is EPDM plastic granules, CAS No. 25038-36-2.
[0058] Example 1 (1) Synthesis of low-viscosity liquid EPDM rubber Using a vanadium-based catalyst, 1500 ml of hexane solvent, 25 g of alkyl aluminum co-catalyst, 1.95 g of VOCl3 main catalyst, 4.5 ml of 1,4-hexadiene third monomer, and 15 ml of ethyl trichloroacetate activator were added sequentially to a reactor. A mixture of ethylene, propylene, and hydrogen in a volume ratio of 1:2:0.09 was introduced at a pressure of 0.5 MPa. The Al / V ratio in the co-catalyst / main catalyst was controlled to be 15. The activator was added to the reaction in five equal portions. The polymerization reaction was carried out at 40 °C and 0.4 MPa for 120 min. After polymerization, the reaction was quenched with an alcohol solution containing hydrochloric acid (the alcohol solution containing hydrochloric acid consisted of anhydrous ethanol and 12 mol / L concentrated hydrochloric acid in a volume ratio of 9:1). After removing the solvent, the liquid polymer obtained was liquid ethylene propylene diene monomer (EPDM) rubber with a molecular weight of 18,000 and an ethylene content of 49%.
[0059] (2) Preparation of liquid EPDM rubber / filler highly dispersed material Using 1.2g of butyllithium as an initiator, 10g of butadiene as a raw material, 80ml of ultra-dry n-hexane as a solvent, and 2.0ml of tetrahydrofuran as a modifier, the reaction was carried out in a glove box under an inert atmosphere. The temperature was controlled at 35℃ and the reaction was stirred for 80min. Then, 20ml of hydrochloric acid-ethanol solution composed of anhydrous ethanol and 12mol / L concentrated hydrochloric acid in a volume ratio of 9:1 was added to terminate the reaction. After washing with methanol and saturated sodium chloride aqueous solution, the product was dried to obtain liquid polybutadiene with a molecular weight of 540 and a 1,2-unit content of 35%. 3.5 g of benzoic acid peroxide was added, and the reaction temperature was slowly increased to 45 °C for 5 hours to obtain a liquid polymer containing epoxy groups. The molar content of epoxy groups in the final polymer was controlled to be 10%. 2.2 g of diethanolamine was added, and the reaction was stirred at 50 °C for 4 hours to obtain a liquid polymer containing hydroxyl groups. Hydrogenation was then carried out at 100 °C using a 5 wt% Pt / C catalyst (the mass fraction of platinum in the Pt / C catalyst was 5%), with the degree of hydrogenation controlled to be ≥99%, to obtain hydrogenated liquid polybutadiene containing hydroxyl groups. Subsequently, filler was added, and the reaction was stirred at 130 °C for 10 hours. After cooling, the filtrate was filtered off, and mercaptopropionic acid and p-toluenesulfonic acid catalysts were added, and the reaction was continued at 120 °C for 10 hours. The mass ratio of hydrogenated liquid polybutadiene containing hydroxyl groups, filler, mercaptopropionic acid, and p-toluenesulfonic acid was controlled to be 15:100:10:0.2. Finally, liquid EPDM rubber is added and mixed in a grinding mill for 60 minutes, keeping the temperature no higher than 35°C, to obtain a highly dispersed liquid EPDM rubber / filler material. The mass ratio of liquid EPDM rubber to filler is controlled at 3:1, and the filler is carbon black.
[0060] (3) Preparation of dome sealing ring material for liquefied gas ships The raw materials are prepared according to the following weight parts: 100 parts solid EPDM rubber, 10 parts liquid EPDM rubber, 90 parts liquid EPDM rubber / filler high dispersion material, 6 parts crosslinking agent, and 5 parts additives. The solid EPDM rubber, liquid EPDM rubber, and liquid EPDM rubber / filler high dispersion material are mixed in an internal mixer. Then, the crosslinking agent and additives are added on a two-roll mill at 140°C and mixed for 40 minutes. The mixture is then molded to obtain the sealing ring material. The crosslinking agent is dicumyl peroxide, and the additives consist of di-tert-butyl peroxide and antioxidant 4010NA in a mass ratio of 1:1.
[0061] Example 2 (1) Synthesis of low-viscosity liquid EPDM rubber Using a vanadium-based catalyst, 1500 ml of hexane solvent, 20 g of alkyl aluminum co-catalyst, 1.50 g of VOCl3 catalyst, 4.5 ml of 1,4-hexadiene third monomer, and 15 ml of ethyl trichloroacetate activator were added sequentially to a reactor. A mixture of ethylene, propylene, and hydrogen in a volume ratio of 1.5:2:0.12 was introduced, and the Al / V ratio in the co-catalyst was controlled to be 15. The activator was added to the reaction in five equal portions. Polymerization was carried out at 40℃ and 0.4 MPa for 120 min. After polymerization, the reaction was quenched with an alcohol solution containing hydrochloric acid (the alcohol solution containing hydrochloric acid consisted of anhydrous ethanol and 12 mol / L concentrated hydrochloric acid in a volume ratio of 8:2). After removing the solvent, liquid polymer liquid ethylene propylene diene monomer (EPDM) rubber with a molecular weight of 10,000 and an ethylene content of approximately 55% was obtained.
[0062] (2) Preparation of liquid EPDM rubber / filler highly dispersed material Using 1.2g of butyllithium as an initiator, 10g of butadiene as a raw material, 80ml of ultra-dry n-hexane as a solvent, and 2.5ml of tetrahydrofuran as a modifier, the reaction was carried out in a glove box under an inert atmosphere. The temperature was controlled at 35℃ and the reaction was stirred for 80min. Then, 20ml of hydrochloric acid-ethanol solution composed of anhydrous ethanol and 12mol / L concentrated hydrochloric acid in a volume ratio of 9:1 was added to terminate the reaction. After washing with methanol and saturated sodium chloride aqueous solution, and drying, liquid polybutadiene was obtained with a molecular weight of 540 and a 1,2-unit content of 58%. 9g of benzoic acid peroxide was added, and the reaction temperature was slowly increased to 45℃ for 5 hours to obtain a liquid polymer containing epoxy groups. The molar content of epoxy groups in the final polymer was controlled to be 25%. 5.5g of diethanolamine was added, and the reaction was stirred at 50℃ for 4 hours to obtain a liquid polymer containing hydroxyl groups. Hydrogenation was carried out at 100℃ using a 5wt% Pt / C catalyst (the mass fraction of platinum in the Pt / C catalyst was 5%), with the degree of hydrogenation controlled to be ≥99%, to obtain hydrogenated liquid polybutadiene containing hydroxyl groups. Subsequently, filler was added, and the reaction was stirred at 130℃ for 8 hours. After cooling, the filtrate was filtered off, and mercaptopropionic acid was added. The reaction was continued at 100℃ for 10 hours using phosphotungstic acid as the catalyst. The mass ratio of hydrogenated liquid polybutadiene containing hydroxyl groups, filler, mercaptopropionic acid, and p-toluenesulfonic acid was controlled to be 10:100:8:0.2. Finally, liquid EPDM rubber is added and mixed in a grinding mill for 60 minutes, maintaining a temperature not exceeding 35°C, to obtain a highly dispersed liquid EPDM rubber / filler material, wherein the mass ratio of liquid EPDM rubber to filler is 1:1. The filler is carbon black.
[0063] (3) Preparation of dome sealing ring material for liquefied gas ships The raw materials are prepared according to the following parts by weight: 100 parts of solid EPDM rubber, 10 parts of liquid EPDM rubber, 80 parts of liquid EPDM rubber / filler high dispersion material, 6 parts of crosslinking agent, and 5 parts of additives. The solid EPDM rubber, liquid EPDM rubber, and liquid EPDM rubber / filler high dispersion material are mixed in an internal mixer. Then, the crosslinking agent dicumyl peroxide and additives are added to a two-roll mill at 140°C and mixed for 40 minutes. The mixture is then molded to obtain the sealing ring material. The crosslinking agent is dicumyl peroxide, and the additives are composed of stearic acid and dicumyl peroxide in a mass ratio of 1:1.
[0064] Example 3 (1) Synthesis of low-viscosity liquid EPDM rubber Using a vanadium-based catalyst, 1500 ml of hexane solvent, 25 g of alkyl aluminum co-catalyst, 2.5 g of VOCl3 catalyst, 4.5 ml of 1,4-hexadiene third monomer, and 25 ml of ethyl trichloroacetate activator were added sequentially to a reactor. A mixture of ethylene, propylene, and hydrogen in a volume ratio of 2:3:0.3 was introduced, and the Al / V ratio in the co-catalyst was controlled to be 15. The activator was added to the reaction in five equal portions. Polymerization was carried out at a temperature of 40℃ and a pressure of 0.5 MPa for 100 min. After polymerization, the reaction was quenched with an alcohol solution containing hydrochloric acid (the alcohol solution containing hydrochloric acid consisted of anhydrous ethanol and 12 mol / L concentrated hydrochloric acid in a volume ratio of 8:2). After removing the solvent, liquid polymer liquid ethylene propylene diene monomer (EPDM) rubber with a molecular weight of 9000 and an ethylene content of approximately 52% was obtained.
[0065] (2) Preparation of liquid EPDM rubber / filler highly dispersed material Using 1.2 g of butyllithium as an initiator, 6.0 g of butadiene as a raw material, 80 ml of ultra-dry n-hexane as a solvent, and 2.5 ml of tetrahydrofuran as a modifier, the reaction was carried out in a glove box under an inert atmosphere. The temperature was controlled at 35 °C and the reaction was stirred for 80 min. Then, 20 ml of hydrochloric acid-ethanol solution composed of anhydrous ethanol and 12 mol / L concentrated hydrochloric acid in a volume ratio of 9:1 was added to terminate the reaction. After washing with methanol and saturated sodium chloride aqueous solution, and drying, liquid polybutadiene was obtained with a molecular weight of 330 and a 1,2-unit content of 50%. 17.5 g of benzoic acid peroxide was added, and the reaction temperature was slowly increased to 45 °C for 5 hours to obtain a liquid polymer containing epoxy groups with a molar content of 50%. 10 g of diethanolamine was added, and the reaction was stirred at 50 °C for 4 hours to obtain a liquid polymer containing hydroxyl groups. Hydrogenation was then carried out at 100 °C using a Pt / C catalyst with a platinum mass fraction of 5%, and the degree of hydrogenation was controlled to be ≥99%, yielding hydrogenated liquid polybutadiene containing hydroxyl groups. Subsequently, filler was added, and the reaction was stirred at 130 °C for 10 hours. After cooling, the filtrate was filtered off, and mercaptopropionic acid was added. The reaction was continued at 90 °C for 10 hours using silicotungstic acid as the catalyst. The mass ratio of hydrogenated liquid polybutadiene containing hydroxyl groups, filler, mercaptopropionic acid, and p-toluenesulfonic acid was controlled to be 10:100:15:0.3. Finally, liquid EPDM rubber is added and mixed in a grinder for 50 minutes, maintaining a temperature not exceeding 35°C, to obtain a highly dispersed liquid EPDM rubber / filler material, wherein the mass ratio of liquid EPDM rubber to filler is 1.5:1. The filler is carbon black and graphene oxide in a ratio of 4:1.
[0066] (3) Preparation of dome sealing ring material for liquefied gas ships The raw materials are prepared according to the following weight parts: 100 parts solid EPDM rubber, 10 parts liquid EPDM rubber, 70 parts liquid EPDM rubber / filler high dispersion material, 6 parts crosslinking agent, and 5 parts additives. The solid EPDM rubber, liquid EPDM rubber, and liquid EPDM rubber / filler high dispersion material are mixed in an internal mixer. Then, the crosslinking agent dicumyl peroxide and additives are added to a two-roll mill at 140°C and mixed for 40 minutes. The mixture is then molded to obtain the sealing ring material. The crosslinking agent dicumyl peroxide and the additives are composed of methyl ethyl ketone peroxide and antioxidant 264 in a mass ratio of 1:1.
[0067] Example 4 (1) Synthesis of low-viscosity liquid EPDM rubber Using a vanadium-based catalyst, 1500 ml of hexane solvent, 20 g of alkyl aluminum co-catalyst, 1.65 g of VOCl3 catalyst, 4.5 ml of 1,4-hexadiene third monomer, and 25 ml of ethyl trichloroacetate activator were added sequentially to a reactor. A mixture of ethylene, propylene, and hydrogen in a volume ratio of 1:2:0.09 was introduced, and the Al / V ratio in the co-catalyst was controlled to be 15. The activator was added to the reaction in five equal portions. Polymerization was carried out at 40℃ and 0.4 MPa for 120 min. After polymerization, the reaction was quenched with an alcohol solution containing hydrochloric acid (the alcohol solution containing hydrochloric acid consisted of anhydrous ethanol and 12 mol / L concentrated hydrochloric acid in a volume ratio of 9:1). After removing the solvent, liquid polymer liquid ethylene propylene diene monomer (EPDM) rubber was obtained with a molecular weight of 18,000 and an ethylene content of approximately 49%.
[0068] (2) Preparation of liquid EPDM rubber / filler highly dispersed material Using 1.2g of butyllithium as an initiator, 10g of butadiene as a raw material, 80ml of ultra-dry n-hexane as a solvent, and 2.5ml of tetrahydrofuran as a modifier, the reaction was carried out in a glove box under an inert atmosphere. The temperature was controlled at 35℃ and the reaction was stirred for 80min. Then, 20ml of hydrochloric acid-ethanol solution composed of anhydrous ethanol and 12mol / L concentrated hydrochloric acid in a volume ratio of 9:1 was added to terminate the reaction. After washing with methanol and saturated sodium chloride aqueous solution, and drying, liquid polybutadiene was obtained with a molecular weight of 540 and a 1,2-unit content of 58%. 9g of benzoic acid peroxide was added, and the reaction temperature was slowly increased to 45℃ for 5 hours to obtain a liquid polymer containing epoxy groups. The molar content of epoxy groups in the final polymer was controlled to be 25%. 5.5g of diethanolamine was added, and the reaction was stirred at 50℃ for 4 hours to obtain a liquid polymer containing hydroxyl groups. Hydrogenation was then carried out at 100℃ using a 5wt% Pt / C catalyst (the mass fraction of platinum in the Pt / C catalyst was 5%), with the degree of hydrogenation controlled to ≥99%, to obtain hydrogenated liquid polybutadiene containing hydroxyl groups. Subsequently, filler was added, and the reaction was stirred at 130℃ for 8 hours. After cooling, the filtrate was filtered off, and mercaptopropionic acid was added. The reaction was continued at 100℃ for 10 hours using phosphotungstic acid as the catalyst. The mass ratio of hydrogenated liquid polybutadiene containing hydroxyl groups, filler, mercaptopropionic acid, and p-toluenesulfonic acid was controlled to be 15:100:10:0.2. Finally, liquid EPDM rubber is added and mixed in a grinding mill for 60 minutes, maintaining a temperature not exceeding 35°C, to obtain a highly dispersed liquid EPDM rubber / filler material, wherein the mass ratio of liquid EPDM rubber to filler is 1:1. The filler is carbon black.
[0069] (3) Preparation of dome sealing ring material for liquefied gas ships The raw materials are prepared according to the following parts by weight: 100 parts of solid EPDM rubber, 5 parts of liquid EPDM rubber, 90 parts of liquid EPDM rubber / filler high dispersion material, 6 parts of crosslinking agent, and 5 parts of additives. The solid EPDM rubber, liquid EPDM rubber, and liquid EPDM rubber / filler high dispersion material are mixed in an internal mixer. Then, the crosslinking agent dicumyl peroxide and additives are added to a two-roll mill at 140°C and mixed for 40 minutes. The mixture is then molded to obtain the sealing ring material. The crosslinking agent is dicumyl peroxide, and the additives are composed of di-tert-butyl peroxide and antioxidant 4010NA in a mass ratio of 1:1.
[0070] Example 5 (1) Synthesis of low-viscosity liquid EPDM rubber Using a vanadium-based catalyst, 1500 ml of hexane solvent, 30 g of alkyl aluminum co-catalyst, 2.5 g of VOCl3 catalyst, 4.5 ml of 1,4-hexadiene third monomer, and 25 ml of ethyl trichloroacetate activator were added sequentially to a reactor. A mixture of ethylene, propylene, and hydrogen in a volume ratio of 1.5:2:0.12 was introduced, and the Al / V ratio in the co-catalyst was controlled to be 15. The activator was added to the reaction in five equal portions. Polymerization was carried out at 40℃ and 0.4 MPa for 120 min. After polymerization, the reaction was quenched with an alcohol solution containing hydrochloric acid (the alcohol solution containing hydrochloric acid consisted of anhydrous ethanol and 12 mol / L concentrated hydrochloric acid in a volume ratio of 9:1). After removing the solvent, liquid polymer liquid ethylene propylene diene monomer (EPDM) rubber with a molecular weight of 10,000 and an ethylene content of approximately 55% was obtained.
[0071] (2) Preparation of liquid EPDM rubber / filler highly dispersed material Using 1.2 g of butyllithium as an initiator, 6.0 g of butadiene as a raw material, 80 ml of ultra-dry n-hexane as a solvent, and 2.5 ml of tetrahydrofuran as a modifier, the reaction was carried out in a glove box under an inert atmosphere. The temperature was controlled at 35 °C and the reaction was stirred for 80 min. Then, 20 ml of hydrochloric acid-ethanol solution composed of anhydrous ethanol and 12 mol / L concentrated hydrochloric acid in a volume ratio of 9:1 was added to terminate the reaction. After washing with methanol and saturated sodium chloride aqueous solution, and drying, liquid polybutadiene was obtained with a molecular weight of 330 and a 1,2-unit content of 50%. 17.5 g of benzoic acid peroxide was added, and the reaction temperature was slowly increased to 45 °C for 5 hours to obtain a liquid polymer containing epoxy groups with a molar content of 50%. 10 g of diethanolamine was added, and the reaction was stirred at 50 °C for 4 hours to obtain a liquid polymer containing hydroxyl groups. Hydrogenation was then carried out at 100 °C using a 5 wt% Pt / C catalyst (with a platinum mass fraction of 5%), controlling the degree of hydrogenation to ≥99%, to obtain hydrogenated liquid polybutadiene containing hydroxyl groups. Subsequently, filler was added, and the reaction was stirred at 130 °C for 10 hours. After cooling, the filtrate was filtered off, and mercaptopropionic acid was added. The reaction was continued at 90 °C for 10 hours using silicotungstic acid as the catalyst. The mass ratio of hydrogenated liquid polybutadiene containing hydroxyl groups, filler, mercaptopropionic acid, and p-toluenesulfonic acid was controlled at 10:100:10:0.2. Finally, liquid EPDM rubber is added and mixed in a grinder for 50 minutes, maintaining a temperature not exceeding 35°C, to obtain a highly dispersed liquid EPDM rubber / filler material, wherein the mass ratio of liquid EPDM rubber to filler is 1.5:1. The filler is carbon black and graphene oxide in a ratio of 4:1.
[0072] (3) Preparation of dome sealing ring material for liquefied gas ships The raw materials are prepared according to the following parts by weight: 100 parts solid EPDM rubber, 5 parts liquid EPDM rubber, 80 parts liquid EPDM rubber / filler high dispersion material, 6 parts crosslinking agent, and 5 parts additives. The solid EPDM rubber, liquid EPDM rubber, and liquid EPDM rubber / filler high dispersion material are mixed in an internal mixer. Then, the crosslinking agent dicumyl peroxide and additives are added to a two-roll mill at 140°C and mixed for 40 minutes. The mixture is then molded to obtain the sealing ring material. The crosslinking agent dicumyl peroxide and the additives are composed of stearic acid and tert-butyl hydroperoxide in a mass ratio of 1:1.
[0073] Example 6 (1) Synthesis of low-viscosity liquid EPDM rubber Using a vanadium-based catalyst, 1500 ml of hexane solvent, 25 g of alkyl aluminum co-catalyst, 2.5 g of VOCl3 catalyst, 4.5 ml of 1,4-hexadiene third monomer, and 25 ml of ethyl trichloroacetate activator were added sequentially to a reactor. A mixture of ethylene, propylene, and hydrogen in a volume ratio of 2:3:0.3 was introduced, and the Al / V ratio in the co-catalyst was controlled to be 15. The activator was added to the reaction in five equal portions. Polymerization was carried out at a temperature of 40℃ and a pressure of 0.5 MPa for 100 min. After polymerization, the reaction was quenched with an alcohol solution containing hydrochloric acid (the alcohol solution containing hydrochloric acid consisted of anhydrous ethanol and 12 mol / L concentrated hydrochloric acid in a volume ratio of 8:2). After removing the solvent, liquid polymer liquid ethylene propylene diene monomer (EPDM) rubber with a molecular weight of 9000 and an ethylene content of approximately 52% was obtained.
[0074] (2) Preparation of liquid EPDM rubber / filler highly dispersed material Using 1.2g of butyllithium as an initiator, 10g of butadiene as a raw material, 80ml of ultra-dry n-hexane as a solvent, and 2.0ml of tetrahydrofuran as a modifier, the reaction was carried out in a glove box under an inert atmosphere. The temperature was controlled at 35℃ and the reaction was stirred for 80min. Then, 20ml of hydrochloric acid-ethanol solution composed of anhydrous ethanol and 12mol / L concentrated hydrochloric acid in a volume ratio of 9:1 was added to terminate the reaction. After washing with methanol and saturated sodium chloride aqueous solution, and drying, liquid polybutadiene was obtained with a molecular weight of 540 and a 1,2-unit content of 35%. 3.5 g of benzoic acid peroxide was added, and the reaction temperature was slowly increased to 45 °C for 5 hours to obtain a liquid polymer containing epoxy groups. The molar content of epoxy groups in the final polymer was controlled to be 10%. 2.2 g of diethanolamine was added, and the reaction was stirred at 50 °C for 4 hours to obtain a liquid polymer containing hydroxyl groups. Hydrogenation was carried out at 100 °C using a 5 wt% Pt / C catalyst with a platinum mass fraction of 5%. The degree of hydrogenation was controlled to be ≥99% to obtain hydrogenated liquid polybutadiene containing hydroxyl groups. Subsequently, filler was added, and the reaction was stirred at 130 °C for 10 hours. After cooling, the filtrate was filtered off, mercaptopropionic acid was added, and the reaction was continued at 120 °C for 10 hours. The catalyst was p-toluenesulfonic acid, and the mass ratio of hydrogenated liquid polybutadiene containing hydroxyl groups, filler, mercaptopropionic acid, and p-toluenesulfonic acid was controlled to be 10:100:10:0.2. Finally, liquid EPDM rubber is added and mixed in a grinding mill for 60 minutes, keeping the temperature no higher than 35°C, to obtain a highly dispersed liquid EPDM rubber / filler material. The mass ratio of liquid EPDM rubber to filler is controlled at 3:1, and the filler is carbon black.
[0075] (3) Preparation of dome sealing ring material for liquefied gas ships The raw materials are prepared according to the following weight parts: 100 parts solid EPDM rubber, 5 parts liquid EPDM rubber, 70 parts liquid EPDM rubber / filler high dispersion material, 6 parts crosslinking agent, and 5 parts additives. The solid EPDM rubber, liquid EPDM rubber, and liquid EPDM rubber / filler high dispersion material are mixed in an internal mixer. Then, the crosslinking agent dicumyl peroxide and additives are added to a two-roll mill at 140°C and mixed for 40 minutes. The mixture is then molded to obtain the sealing ring material. The crosslinking agent is dicumyl peroxide, and the additives are composed of cyclohexanone peroxide and antioxidant 2246 in a mass ratio of 1:1.
[0076] Comparative Example 1 Referring to Example 1, low-viscosity liquid EPDM rubber was synthesized by replacing the liquid EPDM rubber / filler with carbon black. 100 parts of solid EPDM rubber, 10 parts of liquid EPDM rubber, 90 parts of carbon black, 6 parts of crosslinking agent, and 5 parts of additives were added to a two-roll mill and heated at 140°C for 40 minutes to obtain the sealing ring material. The crosslinking agent was dicumyl peroxide, and the additives consisted of di-tert-butyl peroxide and antioxidant 4010NA in a 1:1 mass ratio.
[0077] Comparative Example 2 Referring to Example 1, 110 parts of solid EPDM rubber, 90 parts of carbon black, 6 parts of crosslinking agent, and 5 parts of additives were added to a two-roll mill and molded at 140°C for 40 minutes to obtain a sealing ring material. The crosslinking agent was dicumyl peroxide, and the additives consisted of di-tert-butyl peroxide and antioxidant 4010NA in a mass ratio of 1:1.
[0078] The properties of the sealing ring materials prepared in Examples 1-6 and Comparative Examples 1-2 were tested. Hardness was tested according to GB / T531.1-2008; hot air aging hardness according to GB / T 3512-2014; tensile strength and elongation at break according to GB / T528-2009; hot air aging tensile strength and elongation at break according to GB / T 3512-2014, GB / T 3512-2014, and GB / T528-2009; tear strength according to GB / T 529-2008; low-temperature performance DSC-Tg according to GB / T19466.2-2004; water resistance at 100℃ for 72h for volume change according to GB / T 1690-2010; and resilience according to GB / T 1681-2009. Five samples were taken from each example and comparative example for testing. The results are shown in Table 1 below.
[0079] Table 1 Test results of sealing ring material properties
[0080] Compared to Example 1, Comparative Example 1 replaced the highly dispersed liquid EPDM rubber / filler with a single carbon black filler. The filler was not crosslinked with specific liquid EPDM rubber and hydrogenated liquid polybutadiene, resulting in uneven dispersion with other raw materials in the rubber and insufficient interfacial bonding. This led to a decrease in the elongation at break and the elongation at break after hot air aging of the sealing ring material, and also affected its low-temperature performance, water resistance, and resilience. Compared to Example 1, Comparative Example 2 contained only carbon black filler, crosslinking agent, and additives. The carbon black exhibited poor dispersion at higher filler concentrations, resulting in an uneven crosslinking network structure in the rubber. This also led to a decrease in its tear strength, low-temperature performance, and resilience, and also affected its water resistance.
[0081] The above results indicate that this invention modifies the filler using hydroxyl-containing hydrogenated liquid polybutadiene, achieving chemical bonding between the filler and the hydroxyl-containing hydrogenated liquid polybutadiene through the reaction of functional groups, thus preparing a modified filler containing -SH bonds. Then, based on the low viscosity of liquid EPDM, the modified filler is dispersed in liquid EPDM rubber. Through the reaction of -SH with the carbon-carbon double bonds in the EPDM rubber, the modifier combines with the liquid EPDM rubber, effectively improving the uniform dispersion of the filler in the rubber material and increasing the filler content. Furthermore, through crosslinking of liquid EPDM rubber with solid EPDM rubber, problems such as small molecule migration and blooming in the rubber material are suppressed. Under the synergistic effect of various components, the physical and mechanical properties and low-temperature resistance of the rubber sealing material are effectively improved, resulting in a high-performance rubber sealing material suitable for liquefied gas marine dome sealing.
[0082] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.
Claims
1. A method for preparing a highly dispersed liquid EPDM rubber / filler material, characterized in that, Includes the following steps: (1) Butadiene, initiator, solvent and regulator are stirred once, the reaction is terminated by adding a terminator, then washed and dried to obtain liquid polybutadiene, epoxidant is added to react to obtain liquid polymer containing epoxy groups, diethanolamine is added to stir twice to obtain liquid polymer containing hydroxyl groups, and finally hydrogenation reaction is carried out to obtain hydrogenated liquid polybutadiene containing hydroxyl groups. (2) Hydrogenated liquid polybutadiene containing hydroxyl groups and filler are stirred three times, filtered, mercaptopropionic acid and catalyst are added and stirred four times, and then liquid EPDM rubber is added and mixed to obtain liquid EPDM rubber / filler high dispersion material.
2. The method for preparing the highly dispersed liquid EPDM rubber / filler material according to claim 1, characterized in that, In step (1), the initiator is butyllithium; the solvent is n-hexane; the modifier is tetrahydrofuran; the terminator is acidified ethanol; the epoxidizing agent is one or more of benzoic acid peroxide, formic acid, and hydrogen peroxide mixed solution; in the formic acid and hydrogen peroxide mixed solution, the volume ratio of formic acid to hydrogen peroxide is 1:2~4; the formic acid concentration is 75~80%w / w; the hydrogen peroxide concentration is 30~35%w / w; The acidified ethanol is selected from hydrochloric acid-ethanol solution or acetic acid-ethanol solution; the hydrochloric acid-ethanol solution comprises anhydrous ethanol and concentrated hydrochloric acid in a volume ratio of 8~9:1~2; the concentrated hydrochloric acid has a mass fraction of 36%~38%; the acetic acid-ethanol solution comprises anhydrous ethanol and glacial acetic acid in a volume ratio of 90~95:5~10. The mass ratio of butadiene, initiator, epoxidant, and diethanolamine is 5~9:1:2~15:1~9; The volume ratio of the solvent, regulator, and terminator is 80:2~2.5:20~50; The mass-to-volume ratio of butadiene to solvent is 6-10g:80ml; The molecular weight of the liquid polybutadiene is 200-700; The temperature of the first stirring reaction is 25~50℃ and the time is 30~90min; The reaction temperature after adding the epoxidizing agent is 25~45℃ and the reaction time is 2~5h; The temperature of the secondary stirring reaction is 45~65℃ and the time is 1~4h; The catalyst for the hydrogenation reaction is a Pt / C catalyst with a hydrogenation degree ≥99% and a reaction temperature of 50~120℃; the mass fraction of platinum in the Pt / C catalyst is 5%~10%.
3. The method for preparing the highly dispersed liquid EPDM rubber / filler material according to claim 1, characterized in that, In step (2), the filler is selected from one or more of carbon black, graphene oxide, and montmorillonite; The catalyst is selected from one or more of p-toluenesulfonic acid, phosphotungstic acid, silicotungstic acid, and acidic molecular sieves; The mass ratio of the hydroxyl-containing hydrogenated liquid polybutadiene, filler, mercaptopropionic acid, and catalyst is 5~25:100:5~35:0.05~0.8; The mass ratio of the liquid EPDM rubber to the filler is 0.2~5:1; The three stirring reactions were carried out at a temperature of 120-150℃ for 8-15 hours. The temperature of the four stirring reactions is 90~130℃ and the time is 8~15h; the mixing time is 30~90min.
4. The method for preparing the highly dispersed liquid EPDM rubber / filler material according to claim 1, characterized in that, The synthesis process of the liquid EPDM rubber is as follows: solvent, main catalyst, co-catalyst, third monomer and activator are added to the reaction vessel, mixed gas is introduced to carry out the reaction, quenching is performed, and the solvent is removed to obtain liquid EPDM rubber.
5. The method for preparing the highly dispersed liquid EPDM rubber / filler material according to claim 4, characterized in that, The solvent is n-hexane; the main catalyst is vanadium oxychloride; the co-catalyst is alkylaluminum; the third monomer is selected from one or more of 1,4-hexadiene and 5-methyl-1,5-hexadiene; the activator is selected from ethyl trichloroacetate; the mixed gas includes ethylene, propylene, and hydrogen in a volume ratio of 1~2:2~3:0.09~0.3; the Al / V ratio of the co-catalyst and the main catalyst is 10~40; the reaction temperature is 40~50℃, the pressure is 0.2~0.5MPa, and the time is 40~120min.
6. The method for preparing the highly dispersed liquid EPDM rubber / filler material according to claim 4, wherein the preparation of the liquid EPDM rubber is characterized in that, The ratio of the main catalyst, co-catalyst, third monomer, and activator is 0.3~0.6g:4~6g:1ml; the volume ratio of the third monomer, activator, and solvent is 1:3~6:200~350.
7. A rubber material, characterized in that, Includes the liquid EPDM rubber / filler highly dispersed material as described in any one of claims 1-6.
8. The rubber material according to claim 7, characterized in that, The rubber material comprises the following raw materials in parts by weight: 90-110 parts of solid EPDM rubber, 0-10 parts of liquid EPDM rubber, 30-90 parts of liquid EPDM rubber / filler high dispersion material, 2-8 parts of crosslinking agent, and 1-5 parts of additives; the crosslinking agent is selected from one or more of dicumyl peroxide or sulfur; the additives are selected from one or more of peroxide, stearic acid, antioxidants, etc.; the peroxide is selected from one or more of di-tert-butyl peroxide, dicumyl peroxide, methyl ethyl ketone peroxide, cyclohexanone peroxide, tert-butyl hydroperoxide, and hydrocumyl peroxide; the antioxidant is selected from one or more of antioxidant 4010NA, antioxidant 4020, antioxidant RD, antioxidant AW, antioxidant 264, and antioxidant 2246.
9. The method for preparing the rubber material according to claim 8, characterized in that, Includes the following steps: Solid EPDM rubber, liquid EPDM rubber, and liquid EPDM rubber / filler high dispersion material are mixed and then crosslinking agent and additives are added and mixed and molded; the reaction is carried out at 130~160℃ for 30~90 minutes.
10. The application of the rubber material of claim 8 or the rubber material prepared by the preparation method of claim 9 as a sealing material in the dome seal of a liquefied gas ship.