Common types of thermoplastic elastomers

Thermoplastic elastomer, sometimes called thermoplastic rubber, is a class of copolymer or blend with properties of both thermoplastic and elastomer. The molecular structure can be vividly divided into a hard segment (crystallized at room temperature) and a soft segment.

Thermoplastic elastomers have the following properties:

• hardness range (shaw 0 a - 80 - d) wide, feel good

• diversity of molecular structure, is advantageous for the functional design

• processing way diversification, including extrusion, injection molding, stretch film, blow molding, etc., can be efficient preparation of all kinds of complex products

• recycling scrap can be recycled, saving the costs of production

• proportion is small, there is no obvious creep

• environmental protection sex good, environmentally friendly,pollution-free production process

Today, we introduce common thermoplastic elastomers TPS, TPV, TPU and TPEE, including the structure, properties and applications of the materials, and make a clear comparison of their appearance, feel, chemical resistance to media, mechanical properties and machining properties with a table.

1. TPS

TPS, styrene thermoplastic elastomer, also known as TPE-S, common SBS, SEBS, SIS, etc.

Molecular structure of SBS

SBS is polystyrene - polybutadiene - polystyrene triblock copolymer, is a kind of excellent styrene thermoplastic elastomer, do not need to vulcanize that has similar physical properties of vulcanized rubber, can be directly injection molding, and can be recycled 100 percent.

Molecular structure of SEBS

SEBS, the chemical name of polystyrene - poly(ethylene - butene) - polystyrene block copolymer, is the product of SBS hydrogenation. SEBS does not contain unsaturated double bonds, so its aging resistance, yellowing resistance, temperature resistance, corrosion resistance is better than SBS.

SBS and SEBS have plastic plasticity and rubber elasticity; SBS molecule has the unsaturated molecular structure similar to rubber, so it has the feel and resilience of rubber. SEBS molecule has saturated molecular structure, and its aging resistance, yellowing resistance, temperature resistance and corrosion resistance are better than TPR.

TPS is widely used in daily products, toys and gifts, adult sex toys, hardware tools, sports equipment, medical supplies, automobile accessories, footwear products, wire cables and so on. The difference between the two mainly lies in the specific application.

2. TPV

Thermoplastic dynamic Vulcanizate rubber (Thermoplastic Vulcanizate), abbreviated as TPV, is a type of thermoplastic elastomer in which rubber is distributed in the continuous phase of thermoplastic after dynamic vulcanizate process of rubber and plastic.

According to the type of rubber and plastic, TPVS can be classified into many categories, the common is PP+EPDM combination.

Due to its special dynamic vulcanization system, gives it excellent comprehensive performance (TPV solvent resistance, high temperature resistance and mechanical strength are better than SEBS system elastomers).

• TPV has good elasticity and compression deformation resistance, environmental resistance, aging resistance of epdm, oil solvent resistance and universal neoprene.

• Excellent machining performance: available thermoplastic processing methods such as injection, extrusion processing, high efficiency, simple, do not need to add equipment, high liquidity, small shrinkage rate.

• Green environmental protection, recycling use, and the quality of the repeated use of six times has no obvious drop, comply with the eu environmental requirements.

TPV is widely used in automotive parts, electronic appliances, consumer goods and construction and other fields, specifically automotive sealing materials, automotive engine system, brake and muffler parts, battery shell, wire and cable insulation layer and sheath, daily necessities/medical supplies packaging.

3. TPU

Polyurethane thermoplastic elastomer (TPU), also known as polyurethane rubber, is made of oligomer diisocyanate and polyether or polyester polyol with hydroxy-terminated and low molecular weight diol chain growth agent interaction.

Polyurethane elastomer is a block polymer, which is generally composed of long flexible chains of polyols as soft segments and diisocyanate and chain extender as hard segments. Polyurethane elastomer molecular chains contain a large number of ammonia ester groups, ether, ester and urea groups, which are formed by strong hydrogen bonding. A variety of polyurethane elastomers with very different properties can be obtained from the formulation of a large number of ethers and esters.

TPU molecular structure formula

• TPU are block copolymers, and the composition ratio of hard and soft segments determines the performance of TPU.

• TPU has excellent flexibility and resilience, from very soft to very hard, from very flexible to very rigid, can maintain high elasticity in a wide range of hardness (Shaw A10-D75), higher bearing capacity than other elastomers under the same hardness;

• TPU has excellent wear resistance, its wear resistance is 2 to 10 times of the natural rubber;elongation at break of up to 600% ~ 800%, 300% higher than natural rubber.

• TPU chemical resistance, oil resistance, radiation resistance, resistance to oxygen, ozone resistance, fatigue resistance and vibration resistance, good heat resistance is high, and molding and processing cost is low.

As an excellent elastomer, TPU has a wide range of downstream products, which are widely used in the fields of daily necessities, sporting goods, toys, decorative materials, etc., such as shoe materials, hoses, cables, medical instruments, automotive paint protective film and so on.

4. TPEE

Thermoplastic polyester elastomer TPEE or COPE, is a type of linear block copolymer containing PBT(polybutylene terephthalate) polyester hard segment (crystalline phase) and aliphatic polyester or polyether (amorphous phase) soft segment.

A two-phase separation microstructure is presented between the hard and soft segments of TPEE. The hard segment is an aromatic polyester, which is generally terephthalic acid, while the soft segment is the most common poly (tetrahydrofuran polyether) and aliphatic polyesters. Therefore, according to the types of soft segments, TPEE materials can be divided into polyester and polyether types.

TPEE molecular structure formula

• Through adjust the percentage of hard and soft segment, the hardness of TPEE can change from shaw D32 to D80, its elasticity and strength between rubber and plastic.

• Compared with polyurethane elastomer (TPU), TPEE compression modulus and the tensile modulus is much higher, and made the same the same hardness of TPEE and TPU parts, the former can bear larger load.

• TPEE has excellent heat resistance and low temperature resistance, working temperature range is very wide, can be used in 70 ~ 200 ℃.

• TPEE with excellent melt stability and sufficient thermoplastic, so has good workability, can be used in a variety of thermoplastic processing technology for processing, such as extrusion, injection, blow molding, rotational molding and melt casting molding.

The application scope of TPEE is hydraulic hose, fire hose, shoe material, sports clothing fabric, protective clothing, dust cover. The application amount of TPEE in automobile, electronic appliances, sports goods and other fields is increasing year by year.

Comparison of thermoplastic elastomers

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Company Profile：ANHUI JINKE OPTA POLYMER CO.,LTD . (ANHUI OPTA) is a high-tech enterprise specializing in the research and development, production, sales and service of high performance thermoplastic elastomer, modified plastics, functional masterbatch and other products. Our team has been committed to the research, development, production and sales of thermoplastic elastomer and halogen-free environment-friendly flame retardant materials for more than 20 years. Currently, our TPV technology research and development capability and product market share rank among the forefront in China. Products cover TPV(EPDM/PP), TPO, TPE-S, TPU, TPEE, functional masterbatch and other varieties, widely used in a variety of auto parts, to help achieve automotive lightweight. If you have any technical questions about thermoplastic elastomer materials, please contact us (contact information: 0550-3915588/13655164088 Ms. Han, Website: https://www.optapol.com/).