Thermoplastic elastomer

Thermoplastic Elastomers (TPE) are widely used in seals. TPE is a type of material with rubber elasticity and thermoplastic processability, combining the characteristics of thermoplastics and rubber.

Thermoplastic elastomer is also called thermoplastic rubber [TPR]. This material is a plastic that has properties that are both rubber and thermoplastic. It is a high-polymer material that has the highly elastic properties of vulcanized rubber at room temperature, but at a certain high temperature, can be plasticized and molded like thermoplastic resin. Its “ambitious” characteristics have injected new power into the world of polymers. Some people say it is the so-called “third generation rubber” after natural rubber and synthetic rubber. It is a new polymer material between rubber and resin. It can not only replace part of rubber, but also modify plastics. Its family is very large, collectively known as TPE or TPR. The structural characteristics of the thermoplastic elastomer polymer chain are composed of resin segments (hard segments) and rubber segments (soft segments) with different chemical compositions. The inter-segment forces of the hard segments can form physical cross-links, while the soft segments are highly elastic segments with greater free rotation ability; the soft and hard segments are arranged in an appropriate order and connected in an appropriate manner. In particular, it should be noted that the physical connection of this hard segment is reversible, [that is, at a certain temperature, it will lose the ability to constrain large segments, and it will become plastic. When it drops to normal temperature, these connections are restored and appear like vulcanized rubber cross-linking points. This characteristic makes TPE have dual properties of rubber and plastic. It can produce products through traditional plastic processing equipment without the energy-consuming and complicated vulcanization process. It can also modify plastics.

O-ring seal: O-ring is a common seal widely used in sealing applications. Thermoplastic elastomers have excellent elastic recovery properties and can provide reliable sealing performance to prevent liquid or gas leakage.
Door and window sealing strips: Thermoplastic elastomers can be used in door and window sealing strips to provide effective sound insulation, waterproofing and heat insulation functions. They are able to adapt to the contours of doors and windows of different shapes and sizes and provide good elastic recovery during opening and closing.
Pipe seals: In piping systems, thermoplastic elastomer seals are used to connect joints and prevent leaks of liquids or gases. Due to their good chemical and heat resistance, thermoplastic elastomers are suitable for various industrial applications such as chemicals, petroleum and pharmaceuticals.
Automotive seals: Thermoplastic elastomers are widely used in the automotive industry, such as door seals, glass seals, hood seals, etc. Thermoplastic elastomers are able to withstand a wide range of environmental conditions and mechanical stresses and provide good sealing properties.
Medical device seals: The biocompatibility and chemical resistance of thermoplastic elastomers make them ideal for medical device seals. They can be applied to a variety of medical equipment and devices, such as syringes, infusion sets, and artificial heart valves.

Thermoplastic Elastomers (TPE) can be classified according to their chemical composition, structure and performance characteristics.

According to chemical composition

Olefin thermoplastic elastomers: such as polybutene (Polybutene), polyisoprene (Polyisoprene), etc.
Olefin copolymer thermoplastic elastomers: such as polypropylene-Ethylene Copolymer (TPO), polypropylene-styrene copolymer (TPS), etc.
Ether thermoplastic elastomer: such as polyoxymethylene (POM), etc.
Ester thermoplastic elastomer: such as polycaprolactone (PCL), etc.
Polyurethane thermoplastic elastomer: such as polyether polyurethane (Polyether Polyurethane, TPU), polyester polyurethane (Polyester Polyurethane, TPU), etc.

According to structure

Linear thermoplastic elastomer: such as linear polybutadiene (LPB), etc.
Branched thermoplastic elastomer: such as branched polybutadiene (BPB), etc.
Reticulated thermoplastic elastomer: such as polycaprolactone elastomer (COPE), etc.

According to performance characteristics

Can be divided into: styrene type [TPS], polyolefin type [TPO]. Polyurethane [TPU], polyester [TPEe], polyamide [TPAE], silicone, organic fluorine and acrylate. Among them, styrenic thermoplastic elastomers are the most widely used, but they are rarely used in sealing accessories. The thermoplastic elastomer TPV currently used more frequently in automobiles is sealing strips, including roof seals, windshield seals, Sunroof, roofline seals. Rear windows and trunks, door dividing lines, main doors, auxiliary door seals, light seals, door bezels, reflector frame seals, hood to radiator seals, etc. These seals used to be made of EPDM rubber manufacturing, which can now be completely replaced by thermoplastic elastomers. At the same time, TPV sealing products are also used in shipping containers and are used as the sealing material for international shipping containers. This is mainly because TPV has a long service life, is environmentally friendly, and has reversible recycling, which is slightly better than sealing accessories processed by hot vulcanized EPDM rubber.
Sealing composite materials based on TPU are also widely used, such as making inflatable bladders. The mechanical properties of the material are much better than those of rubber. In recent years, new thermoplastic elastomer varieties have been continuously developed, among which silicone TPE has developed rapidly, such as block copolymers of polystyrene and polydimethylsiloxane, which can be processed without adding silica black and thermal vulcanization. Made to be weather resistant. Ozone resistant, low temperature resistant and highly elastic products. There is also a vulcanized acrylic elastomer that can be processed into seals and can work normally in contact with fuel at 150 degrees Celsius. It can also be made into various automotive bearing seals and transmission sealing components.
There is also a promising polyester thermoplastic elastomer, [TPEE], which has excellent mechanical properties, high strength, good rebound, and best wear resistance and oil resistance. The latest generation of TPEE has broken through the resistance High temperature of 175 degrees Celsius! , can completely replace rubber products, and can also be kneaded with vinyl silicone rubber by adding organic peroxide to produce materials with dual properties of silicone and PTEE for use in sealing devices.

At present, it is feasible to use dynamic vulcanization to prepare new thermoplastic elastomers. According to performance requirements, dynamic vulcanization can be performed with different plastic matrices and various types of synthetic rubber to produce blended thermoplastic elastomers with excellent performance. Now there are many on the market. Such as PA/NBR, PA/EPDM. PA/IIR, very popular.