EPDM

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Ethylene-propylene rubber is a copolymer synthesized from ethylene and propylene as the monomers. Depending on the composition of the monomer units in the rubber molecular chains, there are diene ethylene propylene rubber and terpolymer ethylene propylene rubber. The former is a copolymer of ethylene and propylene, designated as EPM, while the latter is a copolymer of ethylene, propylene, and a small amount of a non-conjugated diene third monomer, designated as EPDM; together they are referred to as ethylene-propylene rubber (EPR). The former requires the use of peroxides for vulcanization, while the latter is vulcanized using sulfur or peroxides. EPDM accounts for approximately 80% to 85% of the world’s total production of ethylene-propylene rubber, and the third monomer is usually vinyl norbornene or dicyclopentadiene. Ethylene-propylene rubber boasts excellent resistance to aging, heat, cold, chemicals (except non-polar solvents), as well as electrical insulation properties. It is widely used in automotive components, waterproofing membranes for building materials, insulation layers for wires and cables, heat-resistant hoses, heat-resistant packing tapes, and a variety of rubber products. Since its industrial production began in the early 1960s, its production volume has grown rapidly, and it has now become the third most widely used synthetic rubber in the world, with consumption second only to styrene-butadiene rubber and polybutadiene rubber. EPDM is primarily used in industries such as automobiles, polymer modifiers, building construction, petroleum additives, and wires and cables. The automotive industry is primarily used for tire components in cars, trucks, and buses, including the car’s radiator tanks and heating hoses, rubber belts, body parts as well as components of the chassis, weatherstripping, door and window seals, floor pans, and ring pipes ； Polymer modifiers include the use of EPDM in the production of thermoplastic polyolefins (TPO), as well as its use in modifying other thermoplastic resins, among which the amount of EPDM/polypropylene used is relatively large ； It is mainly used for single-layer roofing waterproof membranes in building construction ； Petroleum additives are mainly used in engine lubricants to prevent the lubricant from heating up and becoming thinner ； Wires and cables are primarily used for power supply lines in residential and commercial buildings, building wiring, mining cables, wiring for nuclear power plants, car ignition wires, as well as control and signal cables.

The Chinese name for EPDM is ethylene-propylene-diene monomer rubber. Introduction to EPDM: EPDM is a terpolymer of ethylene, propylene, and a non-conjugated diene; its commercial production began in 1963. The global consumption volume each year is 800,000 tons. The most notable characteristic of EPDM is its excellent resistance to oxidation, ozone, and corrosion. Since EPDM belongs to the polyolefin family, it possesses excellent vulcanization properties. Of all rubbers, EPDM has the lowest specific gravity. It can absorb large amounts of filler and oil with little effect on its properties. Therefore, rubber compounds with low production costs can be manufactured. Molecular Structure and Properties: EPDM is a terpolymer of ethylene, propylene, and a non-conjugated diene. Dienes have a special structure, allowing only one of their double bonds to participate in copolymerization, with the unsaturated double bond serving primarily as a cross-linking site. The other unsaturated group will not become part of the polymer’s main chain; it will only serve as a side chain. The main polymer chains of EPDM are completely saturated. This property enables EPDM to resist heat, light, oxygen, and especially ozone. EPDM is essentially non-polar, resistant to polar solutions and chemicals, has a low water absorption rate, and exhibits excellent insulating properties. During the production of EPDM, its properties can be adjusted by changing the amounts of the three monomers, the ethylene-to-propylene ratio, the molecular weight and its distribution, as well as the vulcanization method. Selection of the third monomer for EPDM: Monomers of the third diene type are obtained through the copolymerization of ethylene and propylene, thereby introducing unsaturation into the polymer to enable vulcanization. The selection of the third monomer must meet the following requirements: at most two bonds – one that is polymerizable and one that is vulcanizable; the reaction should be similar to that of two basic monomers; random polymerization of the bonds should result in a uniform distribution; it should have sufficient volatility to facilitate its removal from the polymer; and the vulcanization rate of the final polymer should be appropriate. The type and amount of dienes affect the properties of the polymer. In the production of EPDM, ENB and DCPD are primarily used. The most widely used type in EPDM is ENB, which vulcanizes much faster than DCPD products. Under the same polymerization conditions, the nature of the third monomer influences long-chain branching, in the following order of increasing effect: EPM

A copolymer of ethylene and propylene, coded as EPM. Thanks to those who explained it earlier; I only knew this much

Does anyone know which sets of equipment are available for EPDM production in China? What is the production capacity?

http://bbs.hcbbs.com/viewthread.php?tid=263491&highlight=%D2%D2%B1%FB%CF%F0%BD%BA%D3%A6%D3%C3%BC%BC%CA%F5

Thank you for the introductions from the third and fourth floors; I happen to also want to learn about this area.

Ethylene-propylene rubber (EPR) is a material based on ethylene that came into existence following the invention of the Ziegler-Natta catalysts and the emergence of polyethylene and polypropylene. Copolymer rubbers using propylene as the main monomer are divided into two main categories: ethylene-propylene-diene rubber (EPM) and ethylene-propylene-diene-monomer rubber (EPDM). The former is a copolymer of ethylene and propylene ； The latter is a copolymer of ethylene, propylene, and small amounts of non-conjugated dienes. EPR possesses many excellent properties that other common synthetic rubbers do not have. Coupled with the low cost and easy availability of its monomers as well as its wide range of applications, it has been the fastest-growing among the seven major synthetic rubber types abroad since the 1980s. Its production volume, manufacturing capacity, and consumption rank third in developed countries, behind styrene-butadiene rubber and cis-butadiene rubber. In 1998, the total global production capacity for EPR was approximately 102 tons, while consumption amounted to 814,000 tons. Preliminary estimates show that consumption was around 836,100 tons in 1999, and it is expected to reach 980,000 tons by 2003. The demand growth rate for EPR from 1998 to 2003 was 3.8%, which was higher than the growth rates of demand for styrene-butadiene rubber and cis-butadiene rubber. Currently, the industrial production processes for FPR include solution polymerization, suspension polymerization, and gas-phase polymerization. Below, its technical conditions and key points will be discussed in detail respectively, along with a technical-economic comparison. 1. Solution polymerization process 1.1 Technical status: Industrialization was achieved in the early 1960s; through continuous improvements, this technology has now become mature and is used in many newly built facilities. It is the dominant technology in industrial production, accounting for approximately 77.6% of the total FPR production capacity. This process is a homogeneous reaction carried out in a solvent that can dissolve both the product and the monomer as well as the catalyst system; n-hexane, a straight-chain alkane, is typically used as the solvent, a V-A1 catalyst system is employed, the polymerization temperature ranges from 30 to 50°C, the polymerization pressure is between 0.4 and 0.8 MPa, and the mass fraction of polymer in the reaction products is generally 8% to 10%. The manufacturing process basically consists of steps such as raw material preparation, chemical formulation, polymerization, catalyst removal, recovery and purification of monomers and solvents, as well as coagulation, drying, and packaging. However, since each company possesses its own proprietary technologies in certain aspects or control methods, they employ unique approaches to carrying out this process. Representative companies include DSM, Exxon, Uniroyal, DuPont, Mitsubishi Chemical of Japan, and JSR. The most typical representative of this is DSM Corporation, which is not only the world’s largest producer of EPR but also operates four production facilities in the Netherlands, the United States, Japan, and Brazil, all of which use the solution polymerization process. These facilities account for one-quarter of the world’s total capacity for producing EPR via this method. This company will be used as an example to illustrate this point. DSM uses hexane as a solvent, ethylene-norbornene (ENB) or dicyclopentadiene (DCPD) as the third monomer, hydrogen as a molecular weight regulator, and VOCl3·1/2Al2Et3Cl3 as a catalyst. In addition, accelerants were added to improve catalyst activity and reduce its dosage. The ratio of catalysts used, the pretreatment methods, and the types of accelerants are DSM’s proprietary technologies. The reaction materials are pre-cooled to -500°C, and depending on the grade to be produced, the process is carried out in a single reactor or with two reactors connected in series. The volume of the polymerization reactor is approximately 6 m3. The polymerization conditions are: a temperature below 650°C and a pressure below 2.5 MPa; the heat of reaction is used to raise the temperature of the reactor due to its insulation properties. Under the action of an alkaline vanadium removal agent and hot water, the residual vanadium catalyst in the polymer slurry enters the aqueous phase and is completely removed through two phase-transfer processes. Unreacted monomer is recovered through secondary vacuum flashing and reused. At this point, additives such as stabilizers are added to the glue solution (filling oil is added when producing oil-impregnated grades). After stripping away the remaining ethylene, propylene, and most of the solvents, the liquid is sent to two series-connected coagulation tanks for coagulation; the residual hexane solvent is then evaporated and recovered for reuse. The JC particle slurry undergoes dehydration before entering the drying system, after which it is compressed into blocks or packaged as powder. The waste heat air containing ENB is sent to the incinerator for burning, while the vanadium-containing wastewater is directed to the wastewater vanadium removal unit. Under the neutralizing and flocculating action of the vanadium removal agents, vanadium is incorporated into vanadium slag, which is then regularly disposed of in landfills. The wastewater that has had its vanadium removed is sent to a wastewater treatment plant for further processing. DSM’s EPR solution polymerization process is mature and advanced, offering the following advantages: (1) low investment and optimized process. The optimal design of the reactor meets the requirements for mixing of reaction materials, enables precise control over the parameters of the polymerization process and product quality. It features a high concentration of polymer slurry with a low amount of recycled solvent, a small size for the polymerization tank yet high production capacity. The raw materials and recycled monomers do not require purification, the catalyst is efficient, the vanadium content in the waste streams is low, and the process offers great flexibility. (2) Low production operation costs, long annual operating time of the plant, low consumption of raw materials and catalysts, with advanced control systems used to manage production. (3) The product quality is highly competitive. The product contains low levels of catalyst residues, resulting in few defective units during production. It allows for flexible switching between different product grades, with minimal waste generated during such switching. The product properties can be adjusted to meet customer requirements, and there are many available product grades; the Mooney value can be adjusted within a wide range of 20 to 160. The quality is stable, the reproducibility is good, the variations in product specifications are minimal, and the product has excellent processability. 1.2 Technical features: The technology is well-developed and operates stably; it is the main method for EPR in industrial production ； There are a large variety of product grades, with consistent quality, low ash content, and wide applications ； The product has good electrical insulation properties. However, since polymerization takes place in a solvent, mass and heat transfer are limited; as a result, the mass fraction of the polymer is generally kept between 6% and 9%, with a maximum of only 11% to 14%, leading to low polymerization efficiency. At the same time, since the solvent needs to be recovered and refined, the production process is long, there are many pieces of equipment, resulting in high capital investment and operating costs. 2 Suspension Polymerization Process 2. Technical Status There are few product grades available from the EPR suspension polymerization process, and its applications are limited; it is mainly used for modifying polyolefins. Currently, only Enichem and Bayer use this process, which accounts for 13.4% of the total EPR production capacity. This process relies on the principle that propylene has lower reactivity in copolymerization reactions, with ethylene being dissolved in liquid propylene for copolymerization. Propylene serves both as a monomer and as a reaction medium; its own evaporation is used for cooling in order to control the reaction temperature and maintain the reaction pressure. The resulting copolymer is insoluble in liquid propylene and appears as a fine-grained slurry suspended within it. It can be further divided into the conventional suspension polymerization process and the simplified suspension polymerization process. 2.1.1 General suspension polymerization process: Enichem uses this process, with acetylpropionyl vanadium and AlEt2Cl as catalysts, diethyl malonate dichloride as an activator, HNB or DCPD as a third monomer, and diethyl zinc and hydrogen as molecular weight regulators. Depending on the grade of the product to be produced, ethylene, propylene, a third monomer, and a catalyst are added to a jacketed polymerization reactor equipped with multiple impellers. The reaction conditions are: temperature of 20–20°C and pressure of 0.35–1.05 MPa. The heat of reaction is removed through the evaporation of the monomers in the reaction phase. The mass fraction of the polymer suspended in the reaction phase is maintained at 30%–35%, and the entire polymerization reaction takes place under high degree of automatic control. The resulting polymer acrylonitrile slurry is fed into a washer intermittently (10–15 times per hour) to deactivate the catalyst using polypropylene glycol, followed by washing with an aqueous NaOH solution. The suspension is fed into a stripping tower for stripping, while the unreacted ethylene, propylene, and ENB are refined through recovery systems before being recycled. The colloidal slurry with water is dehydrated using a vibrating screen, then dried by extrusion, compacted, and packaged to yield the finished adhesive. The characteristic of this process is that solvent is not used in polymer purification, resulting in a high polymer concentration; this enhances the production capacity of the equipment. Moreover, the need for solvent circulation and recovery is eliminated, saving energy. 2.1.2 Simplification of the suspension polymerization process: This process was developed on the basis of the conventional suspension polymerization method; it makes use of an efficient titanium-based catalytic system, eliminates the need for catalyst removal, and allows the unreacted monomer to be reused without any treatment. It is usually used in the production of EPM, as flashing does not effectively remove the unreacted third monomer. The process flow is as follows: the reaction takes place in a stirred tank equipped with a jacket, using a catalyst system of TiCl4, MgCl2, and Al(i-Bu); the catalyst efficiency is 50 kg of polymer per g of titanium, the reaction temperature is 27°C, the pressure is 1.3 MPa, and the mass fraction of the polymer is 33%. The steam and material exiting the reactor are compressed to 2.7 MPa and cooled before being returned to the reactor. The polymer slurry has the unreacted monomers removed via flash evaporation; it requires no further purification, and after compression and cooling, it is directly recycled back to the reactor for use. Polymers from which monomers have been removed can be used as finished products without further purification. The product can be in powder, sheet, or granular form. In recent years, Enichem has adopted an improved V-A1 catalytic system, raising catalyst efficiency to 30–50 kg of polymer per g of vanadium; this eliminates the need for a washing step to remove the catalyst, thereby simplifying the process as well. 2.2 Technical characteristics The EPR suspension polymerization process is characterized in that the polymer product is insoluble in the reaction medium, propylene; the viscosity of the system is low, which increases the conversion rate. The mass fraction of the polymer can reach 30%–35%, thereby making its production capacity 4–5 times that of the solution method ； Without processes such as solvent recovery, purification, and coagulation, the process flow is simplified and capital investment is reduced ； Varieties with very high molecular weights can be produced ； The product cost is lower than that of the solution method. Its drawback is that, since no solvent is used, it is difficult to remove the residual catalyst from the polymer ； There are few product varieties and grades, the quality consistency is poor, and the ash content is high ； Polymers are suspended particles that are insoluble in liquid propylene, and it is difficult to keep them in a suspended state; especially when the polymer concentration is high and a small amount of gel forms, the reaction vessel is prone to clogging with gel, and even blockages can occur in the equipment’s pipelines ； The product has poor electrical insulation properties. 3 Gas-phase polymerization process 3.1 Technical status The gas-phase polymerization process for EPR was first industrialized by Himont Company in the late 1980s. In the early 1990s, UCC Company announced that it had started trial production of a pilot-scale EPR plant using the gas-phase process, and its industrial EPR plant with an annual capacity of 91,000 tons came online in 1999. Currently, this process accounts for 9% of the total EPR production capacity. UCC Company’s EPR gas-phase polymerization process is the most representative; it consists of three stages: polymerization, separation and purification, and packaging. Ethylene with a mass fraction of 60%, propylene at 35.5%, and ENB at 4.5% were fed together with a catalyst, hydrogen, nitrogen, and carbon black into a flow ratio bed reactor, where gas-phase polymerization was carried out at 50–65°C and an absolute pressure of 2.07 kPa. The one-way conversion rates of ethylene, propylene, and ENB were 5.2% respectively. 0.58% and 0.4%. The unreacted monomer from the reactor is compressed by the recycle gas compressor and then fed into the recycle gas cooler to remove the heat of reaction, after which it is recycled back to the reactor along with fresh feed gas. The EPR powder discharged from the reactor enters the purification tower without being degassed or depressurized, where residual hydrocarbons are removed using nitrogen. The gas from the top of the purification tower is sent back to the bed reactor via a pump after ENB has been condensed and recovered. The resulting particulate product proceeds to the packaging process. 3.2 Technical characteristics Compared with the first two processes, the gas-phase polymerization process has significant advantages: it features a short process flow with only three steps, whereas traditional processes require seven steps ； No solvent or diluent is required, and there is no need for solvent recovery or purification processes ； There is almost no tri-warm emission, which is beneficial for environmental protection. However, its products have poor versatility, as all of them are black. This is because carbon black is used as a fluidization aid to avoid excessive viscosity of the polymer. Although white and colored products produced by using silane-clay and mica in place of carbon black have been successfully developed, the first industrial production facilities were still only capable of producing black FPR. Among the various production processes for FPR, the solution polymerization process involves the highest investment and costs. The high investment is due to the lengthy process, the difficulty in cooling materials with high viscosity, low production intensity of the equipment, and the very low concentration of the polymer stream after the reaction (only 6%–14%, compared to 33% in suspension polymerization processes); furthermore, the recovery of monomers and solvents requires significant costs ； The high costs are mainly due to high utility expenses, depreciation costs, and fixed costs. This is due to the high consumption of electricity and steam during the production process. The investment and cost of the suspension polymerization process are 77% and 88% of those of a solution polymerization process of the same scale, respectively. It features low investment, reduced raw material consumption and energy use, lower production costs, and diminished expenses for treating waste materials. The capital and product costs for the gas-phase polymerization process are the lowest, accounting for 42% and 68% of those of the solution polymerization process of the same scale, respectively. In summary, although the EPR solution polymerization process involves the highest investment and costs, its products exhibit excellent overall performance, fast vulcanization speeds, and a wide range of applications; it is therefore the most widely used method abroad at present. The suspension polymerization process has a short production cycle, lower investment and costs; however, its product performance does not have any significant advantages, and its range of applications is limited, which is why it is not as widely used as the solution polymerization process at present. The products of the gas-phase polymerization process contain a large amount of carbon black, which results in poor versatility and limits its range of applications; however, its process flow is short. Efficient and clean production helps to reduce costs and protect the ecological environment; it represents a fundamental transformation compared to the traditional solution polymerization process. It is an inevitable trend in the future development of rubber synthesis technology, and has become a project that major foreign petrochemical companies are competing to develop and prioritize. Although this process still has some shortcomings at present, and some companies are even cautious about it, it is unlikely to replace the solution polymerization technique that has been in use in industry for a long time in the near future; however, its prospects for development are optimistic in the long run. Furthermore, this technology is evolving in the direction of vapor-phase synthesis technology for polybutadiene rubber, and it is bound to play a significant guiding role in the future development of synthetic rubber production technologies.

It depends on what kind of information you want to know: synthesis or processing applications? There’s a lot of information; which one should I look at? Currently, only Jilin Petrochemical in China produces EPDM.

Research on EPDM is being carried out by many institutions in China, but the results are still far behind those in Japan, Europe, and the United States; more efforts are needed. The pilot-scale development of EP resins in China is quite good, especially in terms of catalyst development, which has reached world-class standards. However, due to a tendency toward conservatism, domestic manufacturers are still reluctant to use these technologies in production and prefer to rely on imported products. It’s frustrating; the mindset isn’t open enough, and the steps taken aren’t bold enough. There are currently three methods for synthesizing ethylene-propylene: solution polymerization, suspension polymerization, and gas-phase polymerization. These have been mentioned by others earlier, so they will not be described here. Currently, solution polymerization processes dominate the world, but due to their complexity, the key technologies remain in the hands of Western developed countries. There are few people in China engaged in related engineering research, which has limited the development of EPDM. Although Jilin Petrochemical’s EPDM production operates on a certain scale and can meet some of the domestic demand, weak research capabilities result in slow development of new products, preventing the company from occupying a position in the world’s high-end product market ； At the same time, due to lagging advancements in engineering technology, relatively outdated production processes, high energy consumption, and low production capacity, the further expansion of EPDM production has been hindered. In addition, further improvement is needed in the subsequent product development of EPDM!