Over the past 30 years, thermoplastic elastomers (tpes), as the third generation rubber, have developed rapidly all over the world. Now, the yield of thermoplastic elastomer has already surpassed the second generation of liquid rubber, and become a new material in today's rubber industry. In 2000, global consumption of thermoplastic elastomers reached more than 1.4 million t, accounting for 8% of the world rubber consumption (18 million t), and it is estimated that it exceeded 1.5 million t in 2002. Average annual increase of 5% ~ 6%, to higher than rubber 2. A rapid increase of 5 to 3 percent.

   Thermoplastic elastomers have the physical and mechanical properties of vulcanized rubber and the processing properties of soft plastics. The final product can be made easily with a simple plastic processing machine because it is no longer required to undergo hot vulcanization like rubber. With this characteristic, the production process of rubber industry is shortened by l / 4, energy consumption is saved by 25% ~ 40%, and efficiency is improved by 10 ~ 20 times, which can be called another material and technological revolution of rubber industry.

    Thermoplastic elastomer is a new polymer material between rubber and resin. It can not only replace part of rubber, but also modify plastics. Thermoplastic elastomer has the double performance and broad characteristics of rubber and plastic, so that it is widely used in the rubber industry in the manufacture of rubber shoes, rubber cloth and other daily products and rubber tubes, tapes, rubber strips, rubber plates, rubber pieces and adhesives and other industrial supplies. At the same time, thermoplastic elastomers can also replace a large number of rubber used in PVC, PE, PP, PS and other general thermoplastic resin and even PU, PA, CA and other engineering plastics modification, so that the plastics industry has also appeared a new situation.

   First,Types and properties of thermoplastic elastomers

   Thermoplastic elastomers (TPE) can be classified as general TPE and engineering TPE. Germany's Bayer the earliest discovered from 1938 polyurethane TPE, Phillips and Shell in 1963 and 1965, the United States, developed the styrene - butadiene - styrene block polymer TPE, to the us and Europe in the 70 s, countries began to batch production of olefin TPE, technology innovation, new varieties of TPE, constitutes the huge system of the TPE today, make the rubber industry and plastic industry combined with marriage took a step forward greatly.

   The world has industrialized production of TPE are: class styrene (SBS, SIS, SEBS, SEPS), olefin (TP0, TPV), double alkene (TPB, TPI), vinyl chloride (TPVC, TCPE), ammonia ester (TPU), esters (TPEE), amide (TPAE), organic fluorine (TPF), organic silicon and vinyl, etc., almost covers all areas of synthetic rubber and synthetic resin now. They are formed by a solid combination of the resin phase on the main chain forming a hard segment and the rubber phase on the soft segment. Themanufacturing method of TPE can be roughly divided into two types: chemical polymerization and mechanical blending. The former is a separate polymer form, there are main chain copolymerization, grafting copolymerization and ion polymerization. The latter is mainly a blend of rubber and resin, including dynamic vulcanized adhesives (tpe-tpv) with cross-linking vulcanization and interpenetrating  network polymers (tpe-ipn).

   Now, TPE centers on TPS and TPO, and has been rapidly developed in all parts of the world. The production consumption of both has accounted for about 80% of all TPE. Diene TPE and vinyl chloride TPE have also become important TPE varieties. Others, such as TPU, TPEE, TPAE and TPF, turned to engineering. At present, in the world trade market, the price of TPS, TPO and TPVC is about 500 ~ 1400 usd per ton. TPU, TPEE, TPAE and other TPE with heat and oil resistance, high strength and abrasion resistance are about 50% to one time higher than the universality. The high performance TPE class even reaches $20,000 to $30,000 a ton.

   The advantages of TPE are mainly shown in the following aspects：

   （1）Available general thermoplastic molding machine processing, such as injection molding, extrusion molding, blow molding, compression molding, die molding;

   （2）Can be vulcanized with rubber injection molding machine, the time can be shortened from the original 20min or so to less than lmin；
   （3）Available press molding vulcanization, press speed, vulcanization time is short；
   （4）The waste products generated in the production process (escaping the burr edge, extruding the waste glue) and the final waste products can be directly returned for recycling;
   （5）The used TPE products can be simply recycled and reused to reduce environmental pollution and expand renewable resources；
   （6）No vulcanization is needed to save energy. Take the production energy consumption of high-pressure hose as an example: rubber is 188MJ/kg, TPE is 144MJ/kg, which can save energy of more than 25%；
   （7）The self-reinforcing property is large, the formula is greatly simplified, so that the influence of the compound on the polymer is greatly reduced, and the quality performance is easier to grasp；
   （8）It opens up a new way for rubber industry and expands the application field of rubber products;

   The disadvantage is that TPE's heat resistance is not as good as that of rubber. As the temperature rises, the physical property decreases greatly, so the application range is limited. At the same time, compression deformation, resilience, durability equivalent to poor rubber, the price is often higher than the same rubber. But in general, the advantages of TPE are still very prominent, and the disadvantages are in continuous improvement, as a new energy saving and environmental protection rubber raw materials, the development prospects are very good.

Second,Development status of main thermoplastic elastomers

1．Styrene TPE

   Styrene TPE, also known as TPS, for butadiene or isoprene and styrene block type copolymer, its performance is closest to SBR rubber. At present, the world production of TPS has reached more than 700,000 t, accounting for about half of all TPE. The representative type is styrene - butadiene - styrene block copolymer (SBS), widely used in the shoe industry, has largely replaced rubber; At the same time in the adhesive cloth, rubber board and other industrial rubber products in the use is also expanding.SBS is also used as a large number of PS plastic impact modifier, but also asphalt pavement pavement wear, crack, anti-soft and anti-skid excellent modifier.

   The SBS modified PS plastics can not only greatly improve the impact resistance like rubber, but also have a very good transparency. Compared with SBR rubber and WRP powder, SBS modified asphalt pavement is more easily dissolved in asphalt. As a result, although more expensive, it is still widely used. Nowadays, more with waterproof coil material further popularize building housetop, subway, tunnel, groove waterproof, moistureproof above. SBS and s-sbr, NP rubber and made of sponge, than the original PVC, EVA plastic sponge more full of rubber touch, and than vulcanized rubber to light, bright color, pattern clear. Accordingly, suit to make the sponge of rubber shoe medium sole not only, also be the ideal material that travel shoe, athletic shoe, fashionable dress shoe is one-time outsole.

   In recent years, the block styrene polymer (S) that isoprene replaces butadiene has developed rapidly, and its output has accounted for about 1/3 of TPS, and about 90% of it is used in adhesives. The hot melt adhesive made by SIS is not only superior in viscosity, but also good in heat resistance.

   SBS and SIS the biggest problem is not heat, the use temperature generally can not exceed 80℃. At the same time, its strong elongation, weather resistance, oil resistance, wear resistance and so on can not be compared with rubber. For this reason, in recent years, the United States and Europe and other countries have made a series of performance improvements on it. SEBS and SEPS with saturated hydrogenation of SBS and SIS have appeared successively. SEBS (with BR hydrogenation as soft chain segment) and SEPS (with IR hydrogenation as soft chain segment) can greatly improve the impact strength, weather resistance and heat aging resistance. In 1984, mitsubishi chemical made a better performance mixture based on SEBS and SEPS, and named the saturated TPS as "Rubberron". Therefore, SEBS and SEPS are not only universal, but also blending materials used in engineering plastics to improve the weather resistance, wear resistance and heat aging resistance. Therefore, SEBS and SEPS are quickly developed into compatibilizers of nylon (PA), polycarbonate (PC) and other engineering plastics "alloys". In addition, many new varieties such as high transparency TPS for epoxy resin and non-toxic TPS for health care have been developed.

   SBS or SEBS and PP plastic melt blend, can also form IPN type TPS. The so-called IPN is actually two kinds of polymer with networks running through each other, so it is also called interpenetrating network compound. Although most of them belong to thermosetting resins, there are also many TPE thermoplastic elastomers in the form of a cross continuous phase. IPN - TPS formed with SBS or SES as substrate and other engineering plastics can be directly coated without pretreatment. The coating is not easy to scratch, and has a certain oil resistance, elasticity coefficient in the low temperature wide temperature range without any change; The cold resistance and heat resistance of engineering plastics are greatly improved. Styrene compounds and rubber grafting copolymerization can also become TPE with thermoplastic, EPDM/styrene, BR/styrene, ci-iir/styrene, NP/styrene and so on have been developed.

   The world's largest TPS manufacturer is Shell Chem. With Kraton, Carifles goods such as a total of more than 40 brands, marketing all over the world, only the local unit capacity up to 232000 t, 1998 alleged to have growth in recent years, in France, Germany also each have 30000 t production device. American Phillips Petro. The products produced are called Solprene, with a capacity of 35,000 t, Solprene and elastomer in Japan, Enichem in Italy, Belgium, Spain, Mexico, Australia and other countries also use its technology for production, with a capacity ranging from 5,000 to 28,000 t. Japan's JSR and Russia each have 25,000 t production enterprises with their own technologies. Taiwan chi mei company has 90,000 t SBS (including s-sbr) production units.

   TPS, is the world's largest consumer, in our country since 1980 with SBS as the center, with shoe industry in our country (annual output of 6 billion pairs, half the world production of rubber shoes), construction (with waterproofing 13 0 million m, the SBS and APP modified asphalt 80 million M2, leads the world in), as well as road industry (highway 25000 km, the world's second) on the need of TPS, 1999 to 250000 t, 2000 to 300000 t, 2001 to 350000 t, an estimated 2002 years up to 400000 t. The national production was 88,000 t in 1999, 133,000 t in 2000, 168,000 t in 2001 and 216,000 t in 2002, with an average annual growth rate of more than 12%. It is still unable to meet the growing needs of the market. More than half of them will be imported from abroad, of which about 100 thousand tons will be imported from Taiwan, 80% will be used for shoes, and the rest 80 thousand tons will be imported from Korea, Japan, Russia and other places. In 2001, there were 270,000 t (78%) of SBS used in shoes, 45,000 t (13%) of highway asphalt modification, and 3.8%, 3.2% and 2% of other adhesives, waterproof rolls and plastics modification.

   After SBS was developed by Beijing yanshan petrochemical research institute in 1982, there are 3 petrochemical enterprises in production. Beijing yanshan petrochemical has an annual production capacity of 60,000 t and a production capacity of 40,000 t. Yueyang petrochemical has an annual production scale of 100,000 t and a production capacity of 130,000 t. Maoming petrochemical has an annual production capacity of 50,000 t and a production capacity of 50,000 t. In addition to SBS, SIS and SESS are also produced in small quantities. The production brand is up to 25, the product application has covered the shoemaking, the road asphalt modification, the plastic modification, the waterproof coil, the adhesive and so on many fields. China mainland has become one of the world's three major TPS production base, TPS production technology has been introduced to Taiwan and Italy.

2．Olefin TPE

   Olefin TPE is a blend of PP as hard chain segment and EPDM as soft chain segment, TPO for short. Because it is lighter than other TPE (only O. 88), with a heat resistance of up to 100℃, good weather resistance and ozone resistance, it has become another rapidly developing variety in TPE. Since it was first listed in the United States in 1972 under the trade name of TPR by UniroyaI, it has enjoyed double-digit growth for many years, with production reaching 30,000 t in 2000 and an estimated 400,000 t in 2002. Now, TPO has become the main rubber and plastic materials in the fields of automobile and household appliances, such as the United States, Japan and Europe. Especially in the car has accounted for 3/4 of its total, with its manufacturing car bumper, has basically replaced the original metal and PU.

   In 1973, the TPO of dynamic partial vulcanization appeared, especially after the successful development of complete dynamic vulcanization TPO named Santoprere by Mansanto company in 1981, the performance was greatly improved, and the maximum temperature could reach 120℃. This dynamic vulcanization type TPO is called TPV for short. It is mainly used to add a crosslinking agent that can vulcanize the mixture of PP and EPDM in the TPO when it is mixed in the melt, and to make the particles of completely vulcanized fine EPDM crosslinked rubber fully dispersed in the PP matrix by using the force of high shear of mixer, screw machine and other machines. Through the "particle effect" of this cross-linked rubber, TPO's compression deformation resistance, heat aging resistance, oil resistance, etc. have been significantly improved, and even reached the level of CR rubber, so people call it thermoplastic vulcanized rubber.

   TPV has been used instead of NBR and CR to make various rubber products. TPV can also be blended with PE and used with SBS and other TPE to improve the performance. Now, in the automobile has been widely used as gear, rack, ignition wire cover, oil resistant rubber hose, air duct and high-rise buildings, as well as wire and cable, food and medical and other areas, the growth rate of TPS.

   In recent years, Germany launched polymerized TPO on the basis of TPV, which made a new breakthrough in TPV toughness and low temperature resistance. The United States has also developed a better integrated performance IPN type TPO. In 1985, the fully dynamic vulcanized PP/nbr-tpv was grafted with maleic anhydride and part of PP, and treated with amine to form NBR at the end of amine seal. This copolymer can form a small amount of grafting and block in the process of dynamic vulcanization, and can replace NBR used in aircraft, automotive, mechanical and other areas of seals, hoses and so on. Because the two materials have different polarity and are incompatible with each other, MAC compatibilities must be added during blending. Such compatibilizers mainly include: ethylenepolyamines, such as diethylenetriamine or triethylenetetramine, and liquid NBR and polypropylene maleic anhydride compounds.

   Malaysia in 1988 successfully developed PP/NR TPV, it is very high tensile and tear strength, compression deformation is greatly improved, heat up to 100-125℃. At the same time, PP/ENR--TPV was also developed, which made NR react with peracetic acid to make epoxide NR and then blend with PP. The performance is better than PP/nr-tpv and PP/NBR--TPV. It is used in auto parts, wire and cable. During this period, PP/iir-tpv and PP/ci-iir-tpv appeared in the UK, PP/SBR, PP/BR, PP/CSM, PP/ACM, PP/ECO and a series of melt blends were developed in the us, and PP/EVA was made in Germany, which made PP and various rubber blends successful. In addition, EPDM/PVC and IIR/PE appeared in ET Polvmer, Rucodur and other commodities.

   At present, the TPE prepared by dynamic full vulcanization technology in the form of blending has covered 11 kinds of rubber and 9 kinds of resin, and 99 kinds of rubber and plastic blends can be produced. The vulcanized rubber crosslinking density has reached 7×10-5mol/ml (determined by swelling method), that is, 97% of the rubber has been crosslinked vulcanized, the tensile elongation is greater than 100%, and the tensile permanent deformation is less than 50%.

   Now to AES (Monsanto) produced representative varieties Santoprene (EPDM/pp-tpv) and Geolast (NBR/pp-tpv) mainly, widely used in machinery, electrical, construction, food, medical hall and other fields. Especially in the car above, has accounted for 30% to 40%, foreign car TPE consumption has reached 10kg, accounting for about 10% of auto parts. TPV can be used to produce all kinds of parts by plastic processing, such as blow molding, injection molding and extrusion molding. Blow molding products include air purifier duct, gear cover protective sleeve, coupling sheath, etc. Injection products have plug pad, mirror pad, foot brake pad, brake booster guide sleeve, crankshaft cover cover, etc. Extrusion products are wire and cable sheath, fuel tube outer layer of glue and a variety of sealing strip. In particular, the use of TPV on automotive seals has become fashionable, including solid and foam products, static seals and quasi - dynamic/dynamic seals, and so on, has basically replaced rubber.

   At present, TPO accounts for about 80% to 85% and TPV accounts for l5% to 20% in olefin TPE. Because of this, the world's other famous EPDM synthetic rubber manufacturers have launched their own characteristics of TPO, TPV production brand. In order to adapt to different processing methods and USES, generally more than 10-20 kinds. Although most of them do not disclose the specific production method and production capacity, they are all alkene melt-blends. Melt-blend TPV is becoming a new type of rubber and plastic materials and the most popular research and development topic among rubber and plastic manufacturers. There are also various tpo-tpv mutual blending, such as EPDM/PP TPV and NBR/PP--TPV, ACM/PP TPV and EPDM/pa-tpv, etc., are also becoming new modified blending materials.

   In tpo-tpv, TPV accounts for about 5%-20% of l. The 2001 consumption was estimated at 3000t, of which 80% was from AES, TRS. Companies such as DSM of the Netherlands and nandi of Taiwan import. There are 8-10 main manufacturers in China, all of which are small and medium-sized factories with a capacity of about 1000t. Due to performance and quality problems, the total sales volume is less than 500 ~ 600t.

   Since the 1980s, TPO has been developed by tsinghua university, Beijing institute of chemistry, Chinese Academy of Sciences, changchun yinghua institute, Beijing university of chemical technology, Shanghai jiaotong sixth academy, Beijing institute of chemical industry, and yangzi, jinling, yanshan and other companies of petrochemical group. Among them, changchun yinghua research institute, Shanghai jiaotong university, yangzi and jinling petrochemical also developed TPV, which is applied to electric wire and cable, building waterproof coil, automobile sealing strip, protective cover, various kinds of pipe and toothed belt. Qingdao university of science and technology also applied for the national patent of PP/nbr-tpv, and south China institute of tropical crops followed up the research project of PP/NR--TPV. However, due to various reasons, except EPDM/pp-tpv thermoplastic vulcanized rubber, other real industrialization is still very few, so far there is no large professional manufacturers.

   TPV is the fastest growing group in the TPE world, with annual growth rates of 10-20% or more. Because of its processing method and performance most close to vulcanized rubber, mainly in the United States, in the automobile and other products coverage is very broad, very potential for development. At present, a large number of foreign sealing strips, sheath, gaskets and foreskins have been transferred to TPV, and the global consumption of tpo-tpv has reached 360,000 t. However, China's current consumption is less than 25,000 t (TPV 3000t), only 7% of the world's tpo-tpv. Lt foreign goods are sold at a price of up to a bizarre 4,000-5,000 us dollars, which limits the promotion and use. In the future, if the price can be reduced to a normal level, equivalent or slightly higher than the same rubber price, demand will increase exponentially. Taking rubber seal strip as the only product, there are more than 40 production lines in China at present, and 12 main rubber seal strip production enterprises have an annual output of 90,000,000 m and a capacity of 180,000,000 m. If half of them are converted to TPE, the lm weighs 0.4kg, and the tpo-tpv is required to be 18,000t, among which the TPV is at least between 3000-4000t. In addition to tpo-tpv used for expansion of other products, the demand for TPO TPV nationwide in the next five years is likely to reach 35,000-45,000 t, among which the TPV is 0.7-90,000 t. Due to the poor performance and quality of domestic TPV and the high price of imported TPV, experts predict that the domestic consumption can only reach 5000-6000t in 2005 and 1.0 ~ 18,000t in 2010.