Many of our products, such as yoga mats, resistance bands, etc., are made of TPE. TPE has many advantages, and it has been widely used in the fitness equipment industry these years. The following is a detailed introduction and summary of TPE.

Thermoplastic Elastomer (TPE/TPR), also known as artificial rubber or synthetic rubber. Its products not only have the high elasticity, aging resistance, and oil resistance of traditional cross-linked vulcanized rubber, but also have the characteristics of convenient processing and wide processing methods for ordinary plastics.

Introduction

Thermoplastic elastomer, TPE or TPR for short, is the abbreviation for Thermoplastic rubber. It is a kind of elastomer that has the elasticity of rubber at normal temperature and can be plasticized and molded at high temperature. The structural feature of thermoplastic elastomer is that different resin segments and rubber segments are composed of chemical bonds. The resin segments form physical cross-linking points by means of inter-chain forces. The rubber segments are highly elastic segments that contribute to elasticity. The physical cross-linking of the plastic segment changes reversibly with the change of temperature, showing the plastic processing characteristics of the thermoplastic elastomer. Therefore, the thermoplastic elastomer has the physical and mechanical properties of vulcanized rubber and the processing properties of thermoplastic materials. It is a new type of polymer material between rubber and resin.

Since Bayer first prepared thermoplastic polyurethane (TPU) in 1958, TPE has developed rapidly, especially after the advent of styrene-based thermoplastic elastomers in 1963, the theory of thermoplastic elastomer preparation has been gradually improved, and the field of application has been further expanded.

The main use of thermoplastic elastomer(TPE)

Thermoplastic elastomer is a new type of polymer material between rubber and resin. It can not only replace part of rubber, but also modify plastics. The dual properties and wide characteristics of rubber and plastic of thermoplastic elastomers make it widely used in the rubber industry to manufacture rubber shoes, rubber cloth and other daily products and hoses, tapes, rubber strips, rubber sheets, rubber parts and adhesives, etc. Various industrial supplies. At the same time, thermoplastic elastomers can also be used instead of rubber in the modification of general thermoplastic resins such as PVC, PE, PP, PS, and even engineering plastics such as PU, PA, and CA, giving the plastics industry a new situation.

Types of thermoplastic elastomers(TPE)

Thermoplastic elastomers can be summarized as two types of general TPE and engineering TPE. At present, it has developed into more than 30 varieties in 10 categories. From the earliest discovery of polyurethane TPE by Bayer in Germany in 1938, Phillips and Shell in the United States developed styrene-butadiene-styrene block polymer TPE in 1963 and 1965, and began mass production of olefins in the United States, Europe and Japan in the 1970s. Since TPE, technology has continued to innovate, and new TPE varieties have continuously emerged, which constitutes the huge system of today’s TPE, making the rubber industry and the plastic industry a big step forward. The industrialized TPEs in the world include: styrenes (SBS, SIS, SEBS, SEPS), olefins (TP0, TPV), dienes (TPB, TPI), vinyl chlorides (TPVC, TCPE), urethanes Types (TPU), esters (TPEE), amides (TPAE), organic fluorines (TPF), silicones and vinyls, etc., covering almost all areas of synthetic rubber and synthetic resins.

Manufacturing method of thermoplastic elastomer

Generally, according to different preparation methods, thermoplastic elastomers are mainly divided into two categories: chemically synthesized thermoplastic elastomers and rubber-plastic blended thermoplastic elastomers. The former appears in the form of polymers alone, and can be divided into main chain copolymerization, graft copolymerization and ionic polymerization. The latter is mainly a blend of rubber and resin, and there are dynamic vulcanizates (TPE-TPV) and interpenetrating network polymers (TPE-IPN) that appear as cross-linked vulcanization. Now, TPE has developed rapidly around the world with TPS and TPO as the center, and the production and consumption of the two have accounted for about 80% of all TPE. Diene-based TPE and vinyl chloride-based TPE have also become important varieties of general-purpose TPE. Others such as TPU, TPEE, TPAE, TPF, etc. have turned to engineering.

Processing of thermoplastic elastomer

Thermoplastic elastomer has the physical and mechanical properties of vulcanized rubber and the processing properties of soft plastics. Since there is no need to undergo heat vulcanization like rubber, the final product can be easily made using simple plastic processing machinery. This feature of the rubber industry shortens the production process of the rubber industry by 1/4, saves energy consumption by 25% to 40%, and increases efficiency by 10 to 20 times. It can be called another revolution in materials and technology in the rubber industry.

The two main methods for manufacturing and processing thermoplastic elastomers are extrusion and injection molding, and molding is rarely used. Manufacturing and processing thermoplastic elastomers by injection molding is fast and economical. The injection molding methods and equipment used for general thermoplastics are all suitable for thermoplastic elastomers.

Thermoplastic elastomers can also be processed by blow molding, thermoforming, and thermal welding. None of these methods can be applied to thermosetting rubber products.

Thermoplastic elastomers have the following characteristics in processing applications:

1. Standard thermoplastic processing equipment and techniques can be used for processing and molding, such as extrusion, injection, blow molding, etc.
2. Without vulcanization, rubber products can be prepared and produced, reducing vulcanization procedures, saving investment, low energy consumption, simple process, shortening processing cycle, improving production efficiency and low processing cost.
3. The scraps from the corners can be recycled, which saves resources and is also beneficial to environmental protection.
4. Because it is easy to soften at high temperature, the use temperature of the product is limited.

Performance characteristics of thermoplastic elastomers(TPE)

The advantages of thermoplastic elastomers:

1. It can be processed by general thermoplastic molding machines, such as injection molding, extrusion molding, blow molding, compression molding, and transfer molding.
2. It can be vulcanized by a rubber injection molding machine, and the time can be shortened from about 20 minutes to less than 1 minute.
3. It can be molded and vulcanized with an extruder, with fast extruding speed and short vulcanization time.
4. The waste materials generated during the production process (escape burrs, extrusion of waste rubber) and the final waste products can be directly returned for reuse.
5. The used TPE products can be reused after simple regeneration, reducing environmental pollution and expanding resource regeneration sources.
6. There is no need for vulcanization, which saves energy.
7. The self-reinforcing property is large, and the formula is greatly simplified, so that the influence of the compounding agent on the polymer is greatly reduced, and the quality and performance are easier to grasp.
8. To open up new ways for the rubber industry and expand the application fields of rubber products.

Disadvantages of thermoplastic elastomers:

The heat resistance of TPE is not as good as that of rubber, and its physical properties decrease greatly as the temperature rises, so the scope of application is limited. At the same time, the compression deformation, resilience, and durability are inferior to rubber, and the price is often higher than that of similar rubber. But in general, the advantages of TPE are still very prominent, while the shortcomings are constantly being improved. As a new type of energy-saving and environmentally friendly rubber raw material, the development prospects are very promising.

Common types and performance characteristics of thermoplastic elastomers

1. Styrene TPE

Styrenic TPE, also known as TPS, is a block copolymer of butadiene or isoprene and styrene. Its performance is closest to SBR rubber. It is one of the earliest researched varieties of chemically synthesized thermoplastic elastomers. , Is currently the world’s largest production TPE. The representative variety is styrene-butadiene-styrene block copolymer (SBS), which is widely used in the footwear industry and has mostly replaced rubber; at the same time, it is also used in industrial rubber products such as rubber cloth and rubber sheet. It is constantly expanding. SBS is also widely used as an impact modifier for PS plastics. It is also an excellent modifier for wear resistance, crack resistance, softness and skid resistance of asphalt pavement. PS plastic modified with SBS can not only greatly improve the impact resistance like rubber, but also has very good transparency. Compared with SBR rubber and WRP rubber powder, the asphalt pavement modified with SBS is easier to dissolve in the asphalt. Therefore, although the price is more expensive, it is still widely used. Nowadays, waterproof membranes are used to further promote the waterproofing and moisture-proofing of building roofs, subways, tunnels, trenches, etc. The sponge made by using SBS, S-SBR and NP rubber together is more rubbery than the original PVC and EVA plastic sponge, and lighter than vulcanized rubber, with bright colors and clear patterns. Therefore, it is not only suitable for making sponges for rubber shoe midsoles, but also an ideal material for disposable outsoles such as travel shoes, sports shoes, and fashion shoes. In recent years, block styrene polymers (S-S) in which isoprene is substituted for butadiene have developed rapidly, and about 90% are used in adhesives. The biggest problem of SBS and SIS is that they are not heat resistant, and the operating temperature should generally not exceed 80°C. At the same time, its strength, weather resistance, oil resistance, abrasion resistance, etc. cannot be compared with rubber. For this reason, in recent years, the United States, Europe and other countries have made a series of performance improvements to it, and SBS and SIS saturated hydrogenated SEBS and SEPS have appeared successively. SEBS (using BR hydrogenation as soft segment) and SEPS (using IR hydrogenation as soft segment) can greatly improve the impact strength, weather resistance and heat aging resistance. Japan’s Mitsubishi Chemical used SEBS and SEPS as base materials to make a better-performing mixture in 1984, and named this saturated TPS “Rubberron” on the market. Therefore, SEBS and SEPS are not only universal, but also blended materials for engineering plastics to improve weather resistance, abrasion resistance and heat aging resistance, so they quickly developed into nylon (PA), polycarbonate (PC) and other engineering Compatibilizer for plastic “alloy”. In addition, many new varieties have been developed, such as high-transparency TPS for epoxy resins and bio-non-toxic TPS for medical and health use. SBS or SEBS, etc. are melt blended with PP plastics, and can also form IPN type TPS. The so-called IPN is actually a polymer in which two networks penetrate each other, so it is also called an interpenetrating network compound. Although most of them belong to thermosetting resins, there are also many thermoplastic elastomers like TPE in the form of cross-continuous phases. The IPN-TPS formed with SBS or SES as the base material and other engineering plastics can be directly coated without pretreatment. The coating is not easy to scratch, and has a certain degree of oil resistance, and the coefficient of elasticity does not change in a wide temperature range at low temperatures; it greatly improves the cold and heat resistance of engineering plastics. Copolymerization of styrene compounds and rubber can also become TPE with thermoplasticity. EPDM/styrene, BR/styrene, CI-IIR/styrene, NP/styrene, etc. have been developed.

2. Olefin TPE

Olefin TPE is a blend of PP as hard segment and EPDM as soft segment, referred to as TPO. Because it has a lighter specific gravity than other TPEs (only 0.88), heat resistance is as high as 100°C, weather resistance and ozone resistance are also good, so it has become another fast-growing variety in TPE. Dynamic partially vulcanized TPO appeared in 1973, and fully dynamically vulcanized TPO appeared in 1981. The performance has been greatly improved, and the maximum temperature can reach 120°C. This dynamic vulcanization type TPO is referred to as TPV for short. It is mainly used to add a crosslinking agent that can vulcanize the PP and EPDM mixture in the TPO during melt blending, and use internal mixers, screw machines and other mechanical high-shearing The strength makes the fully vulcanized fine EPDM cross-linked rubber particles fully dispersed in the PP matrix. Through the “particle effect” of this crosslinked rubber, the compression set resistance, heat aging resistance, and oil resistance of TPO have been significantly improved, even reaching the level of CR rubber, so people call it thermoplastic vulcanization. glue. Utilizing the oil resistance of TPV, it has now been used to replace NBR and CR to manufacture various rubber products. TPV can also be blended with PE and used with other TPEs such as SBS to complement each other to improve performance. At present, it has been widely used in automobiles as gears, racks, ignition wire sheaths, oil-resistant hoses, air ducts, and crack-resistant gloss seals for high-rise buildings, as well as wire and cable, food and medical fields, and its growth rate has greatly exceeded TPS. In recent years, polymerized TPO has been introduced on the basis of TPV, which has made new breakthroughs in the toughness and low temperature resistance of TPV. The United States has also developed an IPN-type TPO with better overall performance. In 1985, a completely dynamic vulcanization type PP/NBR-TPV appeared again. It was grafted with maleic anhydride and part of PP, and part of NBR was treated with amine to form an amine-terminated NBR. This kind of copolymer that can form a small amount of grafting and block in the dynamic vulcanization process can replace NBR for seals and hoses in aircraft, automobiles, machinery, etc. This blend is incompatible with each other due to the different polarities of the two materials, so MAC compatibilizer must be added during blending. Such compatibilizers mainly include: ethylene polyamine compounds, such as diethylene triamine or triethylene tetramine, as well as liquid NBR and polypropylene maleic anhydride compounds. Malaysia successfully developed PP/NR TPV in 1988. It has high tensile and tear strength, and its compression deformation is greatly improved. The heat resistance can reach 100-125°C. At the same time, PP/ENR–TPV was also developed, which is obtained by first reacting NR with peroxyacetic acid to produce epoxidized NR, and then melt blending with PP. The performance is better than PP/NR-TPV and PP/NBR-TPV, used in auto parts and wires and cables. During this period, PP/IIR-TPV, PP/CI-IIR-TPV appeared in the United Kingdom, and the United States developed a series of melt blends such as PP/SBR, PP/BR, PP/CSM, PP/ACM, PP/ECO, etc. As a material, Germany made PP/EVA, which made the blending of PP and various rubbers succeed. In addition, EPDM/PVC, IIR/PE, etc. are seen in the market. At present, TPE prepared by dynamic full vulcanization technology in the form of blends has covered 11 types of rubber and 9 types of resins, and 99 types of rubber-plastic blends can be produced. The cross-linking density of the vulcanized rubber has reached 7×10-5mol/ml (determined by the swelling method), that is, 97% of the rubber is cross-linked and vulcanized, the resistance to elongation rate is greater than 100%, and the tensile permanent deformation does not exceed 50% . TPV can be used to produce various parts by blow molding, injection molding and extrusion molding, which are commonly used in plastic processing. Blow molding products include automobile air purifier ducts, gear cover protective sleeves, coupling sleeves, etc. Injection molded products include stopper pads, reflector pads, pedal brake pads, brake booster catheter sheaths, crankshaft cover sheaths, etc., and can also be used to manufacture timing belts. Extruded products include wire and cable sheath, fuel pipe outer layer glue and various sealing strips. Especially for car sealing strips, the use of TPV has become fashionable, including solid and foamed products, static sealing and quasi-dynamic/dynamic sealing products, etc., which have basically replaced rubber. At present, in olefin-based TPE, TPO accounts for about 80%-85%, and TPV accounts for 15-20%. In order to adapt to different processing methods and uses, there are generally more than 10-20 types. Although their specific production methods and production volumes are mostly unannounced, they are nothing more than various melt blends of olefins. Melt blended TPV is becoming a new type of rubber and plastic material and the most popular research and development topic that various rubber and plastic manufacturers are competing to develop. There are also various blends of TPO-TPV, such as EPDM/PP TPV and NBR/PP-TPV, ACM/PP TPV and EPDM/PA-TPV, etc., which are also becoming new modified blend materials.

3. Diene TPE

Diene TPE is mainly the isomer of natural rubber, so it is also called thermoplastic trans-natural rubber (1-NR). As early as 400 years ago, people discovered this material as natural rubber, but because it is produced on wild trees such as Gutabo and Balata, which are different from the three-leaf rubber tree, it is called Gutabo rubber and Pakistan. Lata rubber. Although this kind of T-NR has been used for submarine cables and golf skins for more than 100 years, it has been in a thermoplastic state and has strong crystallinity, so its supply is limited and its use has not been expanded for a long time. After 1963, the United States, Canada, Japan and other countries successively made synthetic T-NR-trans polyisoprene rubber with organometallic catalysts, called TPI. Its microstructure is just the opposite of isoprene rubber (IR), with 99% trans bonding, 40% crystallinity, and a melting point of 67°C, which is very similar to natural gutta-percha and balata rubber. Therefore, natural products have begun to be gradually replaced, and further developed to be used in orthopedic appliances, plaster substitutes and sports protection equipment. In recent years, using TPI’s excellent crystallinity and temperature sensitivity, it has been successfully developed as a shape memory rubber material, and it has been favored by people. From the structural point of view, TPI is a thermoplastic rubber composed of high crystallinity formed by the trans structure as the hard segment, and then combined with the soft segment of the other arbitrary shape in the state of the elastic phase. Compared with other TPEs, it has the advantages of good mechanical strength, scratch resistance, and vulcanization. The disadvantage is that the softening temperature is very low, generally only 40-70℃, and its use is limited. Also under development in China is Eucommia rubber, which is produced in large quantities on Eucommia trees in the areas of Hunan, Hubei, Sichuan, and Guizhou. It is also a kind of trans-l,4-polyisoprene natural rubber with abundant resources and quite abundant resources. Development potential. In 1974, a Japanese company successfully developed the isomer of BR rubber (cis-1,4 polybutadiene)-syndiotactic 1,2 polybutadiene, TPB for short. It is a syndiotactic polybutadiene rubber containing more than 90% l and 2 positions. The microstructure is a block polymer composed of a crystalline part with the same structure of the hard segment and an arbitrary-shaped soft part of the soft segment. Although its heat resistance and mechanical strength are not as good as rubber, it is widely used in shoemaking, sponge, light film and other industrial rubber products with good transparency, weather resistance, electrical insulation and photodegradability. The biggest difference between TPB and TPI and other TPE is that it can be vulcanized. It solves that general TPE cannot be vulcanized with sulfur and peroxide. Special devices such as electronic waves and radiation must be used. It can improve the quality of modification, thereby improving the shortcomings of TPE’s heat resistance, oil resistance and poor durability. TPB can be arbitrarily processed within the melting point range of 75-1 10°C. It can be used to produce non-vulcanized injection molded slippers and casual shoes, or vulcanized foam can be used to produce midsoles for sports shoes and travel shoes. Compared with the EVA sponge midsole, it is not easy to collapse and deform, and it is comfortable to wear, which is beneficial to improve the effect of sports competition. The film made by TPB has good air permeability, water resistance and transparency, is easy to be decomposed by light, and is very safe. It is especially suitable for household and vegetable and fruit fresh-keeping packaging.

4. Vinyl chloride TPE

Vinyl chloride TPE is divided into two categories: thermoplastic PVC and thermoplastic CPE. The former is called TPVC and the latter is called TCPE. TPVC is mainly an elastic modifier of PVC, which is divided into two forms: chemical polymerization and mechanical blending. Mechanical blending is mainly a blend (PVC/NBR) formed by mixing partially cross-linked NBR into PVC. TPVC is actually just an extension of soft PVC resin, but because the compression deformation is greatly improved, a rubber-like PVC is formed. This kind of TPVC can be regarded as a modified product of PVC and a substitute for rubber. It is mainly used to manufacture hoses, rubber sheets, rubber cloth and some rubber parts. At present, more than 70% is consumed in the automotive field, such as car steering wheels, wiper strips, and so on. For other purposes, wires account for about 75%, and construction waterproof film accounts for about 10%. In recent years, it has begun to expand to household appliances, gardening, industry, and raincoats for daily use. At present, the blends of PVC and NBR, modified PVC and cross-linked NBR are mainly sold in large quantities in the international market, which has become the most successful example of rubber and plastic blending. The nitrile rubber manufacturers in the United States, Japan, Canada, Germany and other countries have mass production. PVC/NBR materials have been separately formed in the industry, and they are used to manufacture various rubber products such as hoses, rubber sheets, and tapes. Blends of PVC and other polymeric materials, such as blends of PVC/EPDM, PVC/PU, and PVC/EVA, as well as blends of PVC, ethylene, and acrylate, have also come out and put into production one after another. With the increasingly stringent environmental protection requirements, the acid gas escaping from TPVC has always been difficult to completely solve, which pollutes the environment. Recently, the growth rate in the world has declined, and the scope of use has been greatly affected. The main TPVC produced and used in my country is HPVC, which has been studied since the 1990s and only a small amount of production and supply. At present, most of them are blends of PVC/NBR and PVC/EVA. Except for individual commodity blends, most of them are blended by rubber processing plants. They are widely used in the manufacture of oil tanks, hoses, rubber shoes, etc., and have partially replaced CR and NBR, NR, and SBR have very good effects, and their usage is increasing year by year. Now TCPE with TPE function, which is blended with CPE rubber and CPE resin, has also begun to be used. In the future, TPVC and TCPE may become my country’s new rubber and plastic materials to replace some NR, BR, CR, SBR, NBR rubber and PVC plastics.

5. Polyurethane TPE

Polyurethane TPE is a thermoplastic polyurethane rubber composed of isocyanate-reactive urethane hard segments and polyester or polyether soft segments that are mutually block-bonded, referred to as TPU. TPU has excellent mechanical strength, abrasion resistance, oil resistance and flexibility resistance, especially the most outstanding abrasion resistance. The disadvantages are poor heat resistance, hot water resistance and compression resistance, easy to turn yellow in appearance, and easy sticking to molds during processing. At present, it is mainly used in the manufacture of ski boots, hiking boots and other sports goods in Europe, America and other countries, and it is also used to produce various sports shoes and travel shoes in large quantities, and the consumption is very large. TPU can also produce automobile, machinery, clock and other parts through injection molding and extrusion molding methods, and is widely used in high-pressure hoses (outer rubber), pure hoses, sheets, transmission belts, conveyor belts, wires and cables, tapes and other products. Among them, injection molding accounts for more than 40%, and extrusion molding is about 35%. In recent years, in order to improve the processing performance of TPU, many new easy-to-process varieties have emerged. If it is suitable for two-color molding, it can increase transparency, high flow, and high recycling, which can improve the processing and production efficiency of shoe-making TPU. A non-plastic, low-hardness, easy-to-process TPU used to make transparent hoses. Reinforced TPU that can improve rigidity and impact with glass fiber reinforced specially for large parts such as automobile bumpers. Especially when reactive components are added to TPU, after thermoforming, through aging, the formation of incomplete IPN (IPN formed by cross-linked polymer and non-cross-linked polymer) has developed rapidly. This IPN TPU further improves the physical and mechanical properties of the TPU. In addition, TPU/PC blended alloy type TPU further improves the safety performance of automobile bumpers. In addition, there are TPUs with high moisture permeability, TPUs with conductivity, and TPUs dedicated to living organisms, magnetic tapes, safety glass, etc. have appeared.

Research Progress of New Thermoplastic Elastomers

In recent years, with the development and application of polymer structure design theory (that is, through systematic research on the relationship between the molecular chemical structure and physical properties of materials, material materials with specific chemical structures can be synthesized according to application requirements), and dynamic vulcanization With the in-depth research and development of theory and technology, many new types of thermoplastic elastomer materials have been coming out [3], and a preliminary industrialization scale has been formed.

1. Polyamide thermoplastic elastomer

Polyamide-based thermoplastic elastomer (TPAE) refers to a type of block copolymer composed of high-melting crystalline polyamide hard segments and non-crystalline polyether or polyester soft segments. The hard segment in the TPAE structure is usually polycaprolactam, polyamide 66, polylaurolactam, aromatic polyamide, etc., and the soft segment is usually polyethylene glycol, polypropylene glycol, polybutylene glycol, double-end hydroxy fat Group glycans and so on. Due to the wide range of materials that can be used for soft and hard segments, and the degree of polymerization and the blending ratio of soft and hard segments can be adjusted, TPAE products with different properties can be designed and prepared according to different uses. The type of polyamide hard segment prepared determines the melting point, chemical resistance and relative density of TPAE; the type of polyether or polyester soft segment determines the low temperature characteristics of TPAE, hygroscopicity, antistatic properties and stability to certain chemicals In addition, the ratio of the amount of soft and hard segments has a decisive influence on the elasticity, hardness and chemical resistance of TPAE. Therefore, controlling the blending ratio of the soft and hard segments in the linear molecular chain is the key technology for the production of TPAE. Polyamide thermoplastic elastomer has good mechanical properties and elasticity, and has excellent wear resistance and flexibility. It is a type of thermoplastic elastomer suitable for use at high temperatures.

2. Thermoreversible covalently crosslinked thermoplastic elastomer

Thermoreversible covalent crosslinking of thermoplastic elastomers uses Diels-Alder reaction, using cyclopentadiene (CPD) as the crosslinking agent, and using the thermally reversible conversion characteristics of CPD and dicyclopentadiene, The derivatives containing CPD or DCPD are introduced as cross-linking bonds of linear polymer molecules containing active groups to convert them into thermally reversible covalently cross-linked thermoplastic elastomers containing -C -C-covalent cross-links.

When synthesizing CPD and DCPD derivatives, the raw materials, intermediates and products used contain CPD, DCPD conjugated diene ring, and some also contain C = C unsaturated bonds, which makes the raw materials and raw materials, raw materials and intermediates (or Diels-Alder reaction is very easy to occur between product), product and product, resulting in difficult product separation, low yield (20%-50%), and complex structure. In addition, it is also required that there should be no double bond structure in the main chain of the polymer macromolecule, otherwise the Diels-Alder reaction between the double bond of the main chain and the CPD will form an irreversible crosslinking structure, resulting in thermally reversible crosslinking as the processing times increase The behavior gradually declines. Therefore, the most promising method for market applications is to synthesize a DCPD (or CPD) derivative crosslinking agent, and then thermally reversibly crosslink chlorine-containing polymers, carboxyl-containing polymers and polymers with pendant hydroxyl groups.

3. Metallocene catalyzed polyolefin thermoplastic elastomer

Metallocene-catalyzed polyolefin TPE was first developed by Dow Chemical Company in the United States using Insite technology, and was introduced to the market in 1994. It is a TPE variety that has developed rapidly in recent years. The metallocene catalyst has the characteristics of high catalytic activity and single active center. The catalyzed polymer has the advantages of narrow molecular weight distribution and controllable polymer structure. It has become a new generation of olefin polymerization catalyst after Ziegler-Natta catalyst.

4. Crustacean liquid crystal thermoplastic elastomer

In recent years, thermoplastic liquid crystal elastomers with both high elasticity and liquid crystallinity have increasingly become another research focus in the field of thermoplastic elastomers. Thermoplastic liquid crystal elastomer usually refers to a tri-block or multi-block polymer with liquid crystallinity. At present, the most promising thermoplastic liquid crystal elastomer in the market is mainly a shell-type liquid crystal thermoplastic elastomer.

5. Bio-based thermoplastic elastomer

Traditional polymer materials are mainly synthesized from petrochemical resources. With the continuous consumption of non-renewable resources such as petroleum, the development of polymer materials is facing huge challenges. In order to reduce the dependence on non-renewable resources such as petroleum and realize the sustainable development of the polymer materials industry, bio-based polymer materials have attracted more and more attention. Bio-based thermoplastic elastomers are a type of thermoplastic elastomer material prepared from biomass monomers. Since the monomers are derived from natural organisms, their resources are very sustainable.

6. New type of thermoplastic vulcanizate TPV

With the development of dynamic vulcanization technology, on the basis of general-purpose thermoplastic elastomers (EPDM/PP TPV), the development and preparation of functional TPV materials (such as tire TPV, medical TPV, etc.) has also become a research hotspot in this field.