Advantages And Disadvantages Of TPE/TPR/TPV/TPU/TPEE

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Thermoplastic Elastomer It is an environmentally friendly, low-carbon composite material that has the properties of rubber (high elasticity, compression permanent deformation, etc.) and the processing characteristics of plastic (simple process).

TPE is environmentally friendly, non-toxic and safe, and has excellent colorability, soft touch, weather resistance, fatigue resistance and temperature resistance. It has excellent processing performance and can be recycled to reduce costs. It can be secondary injection molded, coated and bonded with base materials such as PP, PE, PC, PS, ABS, etc., or molded alone.

The TPE (thermoplastic elastomer) that has been industrially produced in the world includes: styrenes (SBS, SIS, SEBS, SEPS), olefins (TP0, TPV), dienes (TPB, TPI), vinyl chlorides (TPVC, TCPE), urethanes (TPU), esters (TPEE), amides (TPAE), organic fluorines (TPF), silicones and ethylenes, etc., covering almost all areas of synthetic rubber and synthetic resins.

Dynamic full vulcanization: refers to the process in which the rubber phase undergoes chemical crosslinking under the action of a crosslinking agent when thermoplastic resin and rubber are melt-blended, and is sheared and broken into a large number of micron-sized crosslinked rubber particles with the help of strong mechanical shearing, and dispersed in the continuous phase of the thermoplastic resin.

When PP is used as a hard segment and EPDM is used as a soft segment for melt blending, a crosslinking agent is added to vulcanize it, and the mechanical high shearing force of internal mixers, screw machines, etc. is used to make the fully vulcanized EPDM crosslinked rubber particles fully dispersed in the PP matrix with a micron size (less than 1 micron).

★TPV has the heat resistance and low compression deformation properties of vulcanized rubber;

★Excellent processing performance: It can be processed by thermoplastic processing methods such as injection and extrusion, which is efficient, simple and easy, without adding equipment, high fluidity and small shrinkage.

★TPV does not require vulcanization and is easy to process, which shortens the production process of the rubber industry by 1/4, saves 25% to 40% of energy consumption, and improves efficiency by 10 to 20 times. It can be called another material and process technology revolution in the rubber industry.

★Light specific gravity (0.90-0.97), uniform appearance quality, high surface grade and good feel.

★TPV can be used normally at -60℃ to +135℃; when not under load, the high temperature resistance can reach +150℃.

★Wide range of soft and hard applications, 25A-70D;

★The advantage of easy dyeing greatly increases the freedom of product design.

★Green and environmentally friendly, recyclable, and no significant performance degradation after six repeated uses

★TPV has excellent ozone resistance and weather resistance;

★TPV has dynamic fatigue resistance, excellent weather resistance, and good wear resistance;

★Good elasticity and compression deformation resistance, environmental resistance, and aging resistance are equivalent to EPDM rubber.

★TPV has excellent corrosion resistance to water-based acid and alkali liquids and polar oils

★TPV's oil and solvent resistance is comparable to that of general-purpose chloroprene rubber.

★TPV has excellent acid and alkali resistance and is highly resistant to acid and alkali cleaning agents. It can still maintain its original properties after long-term use in acid and alkali environments.

A simple physical blend of PP and EPDM (partially vulcanized), referred to as TPO.

In Japan, except for TPU, other thermoplastic elastomer materials are usually collectively referred to as TPO, that is, TPO=TPE=TPV=TPR as the Japanese say; but the current TPO is basically improved to highly vulcanized rubber (similar to TPV), but some SEBS is added for modification, so you need to ask more when you meet Japanese customers.

In 1984, Mitsubishi Chemical of Japan made a better performance mixture with SEBS and SEPS as the base material, and named this saturated TPS "Rubberron" for the market. Therefore, SEBS and SEPS are not only universal, but also melt-blended with PP plastic to 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; most of them belong to thermosetting resins, but there are also many thermoplastic elastomers like TPE that appear in the form of cross-continuous phases).

IPN-TPS formed by using SBS or SEBS 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 oil resistance. The elastic coefficient does not change much in a wide temperature range at low temperatures, which greatly improves the cold and heat resistance of engineering plastics. Styrene compounds and rubber grafting copolymerization can also become thermoplastic TPE. EPDM/styrene, BR/styrene, CI-IIR/styrene, NR/styrene, etc. have been developed.

Summary:

a. Both TPO and TPV belong to polyolefin thermoplastic elastomers. In order to distinguish them, TPV forums usually refer to them as polyolefin thermoplastic elastomers (also known as: partially vulcanized rubber of thermoplastic elastomers);

b. TPO (TPO is basically a brand name of Japanese companies, such as Riken TPO) is similar to the domestic TPV system, with a price of around 45, and a very tight production capacity (consumed by the Japanese automotive industry).

Domestically, it is generally called "TPE" material, which basically belongs to styrene thermoplastic elastomer. Styrene TPE (called TPS abroad) is a copolymer of butadiene or isoprene and styrene block type, and its performance is close to SBR rubber.

Advantages: It has the high elasticity of rubber and the characteristics of injection molding; it is environmentally friendly, non-toxic and safe, has excellent colorability, soft touch, weather resistance, fatigue resistance and temperature resistance, excellent processing performance, no need for vulcanization, can be recycled to reduce costs, can be secondary injection molding, coated and bonded with base materials such as PP, PE, PC, PS, ABS, etc., or can be molded alone.

Disadvantages: The biggest problem of SBS and SIS is poor heat resistance, and the use temperature generally cannot exceed 80℃. At the same time, its strength, elongation, weather resistance, oil resistance, wear resistance, etc. cannot be compared with rubber.

In recent years, the United States, Europe and other countries have made a series of performance improvements on it, and SEBS and SEPS, which are saturated hydrogenated SBS and SIS, have appeared one after another. SEBS (with hydrogenated BR as soft segment) and SEPS (with hydrogenated IR as soft segment) can greatly improve the impact strength, and also have good weather resistance and heat aging resistance.

The modified TPE can withstand temperatures up to 110°C. V0 flame retardant and halogen-free flame retardant series of SEBS/SEPS modified TPE are commonly used in Apple headphone cables and other applications due to their good tensile properties and smooth surface. The main manufacturers are from Taiwan, but the price is expensive.

TPR was first coined by Americans. At that time, there was no unified name for thermoplastic elastomers. It was customary to use the English abbreviations TPR to represent thermoplastic rubber and TPE to represent thermoplastic elastomer (both are used in relevant materials and books); and it was applied to simple blends of PP and EPDM. Later, AES's PP/EPDM type TPV (initially called TPR and later changed to TPV) also used this name. Later, this name may have been called by Taiwanese and became popular in the mainland.

Regardless of how it is called abroad, TPR and styrene TPE in China currently belong to the same concept, representing thermoplastic styrene-butadiene-styrene block copolymers, which are customarily called thermoplastic styrene-butadiene rubber, that is, TPE = styrene TPE in China.

However, due to historical and translation issues, the Chinese abbreviation of TPV (thermoplastic dynamic vulcanized rubber) is thermoplastic rubber (English: Thermoplastic Rubber), that is, TPR. This is why we don't tell our customers that our PP/EPDM TPV material is called TPR, because some customers may think it is a styrene elastomer. If it is based on SBS, the price is much lower than TPV.

Thermoplastic polyester elastomer, referred to as 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. TPEE is a high-performance engineering-grade elastomer with the advantages of high mechanical strength, good elasticity, impact resistance, creep resistance, cold resistance, bending fatigue resistance, oil resistance, chemical and solvent corrosion resistance, etc. It has good processability and can be filled, reinforced and alloyed. It has been widely used in automotive parts, hydraulic hoses, cables and wires, electronic appliances, industrial products, stationery, biomaterials and other fields.

Physical and chemical properties of TPEE:

● Mechanical properties

By adjusting the ratio of soft and hard segments, the hardness of TPEE can be changed from Shore D32 to D80, and its elasticity and strength are between rubber and plastic. Compared with other thermoplastic elastomers (TPE), TPEE has a higher modulus than other TPEs of the same hardness under low strain conditions. When modulus is an important design condition, TPEE can reduce the cross-sectional area of ​​the product and reduce the amount of material used.

● Tensile strength

Compared with polyurethane elastomer (TPU), TPEE's compression modulus and tensile modulus are much higher. When TPEE and TPU of the same hardness are used to make the same part, the former can withstand a larger load. Above room temperature, TPEE has a very high bending modulus, which is suitable for making cantilever beams or torque-type components, especially for making high-temperature components. TPEE has good low-temperature compliance, and its low-temperature notched impact strength is better than other TPEs, and its wear resistance is comparable to that of TPU. TPEE has excellent fatigue resistance, which, combined with its high elasticity, makes this material an ideal material for multiple cyclic load use conditions, suitable for making gears, rubber rollers, flexible couplings, belts, etc.

●Heat resistance

TPEE has excellent heat resistance. The higher the hardness, the better the heat resistance. The operating temperature of TPEE is very high and can adapt to the baking temperature (150-160℃) on the automobile production line, and it has little loss of mechanical properties at high temperature. When used above 120℃, the tensile strength of TPEE is much higher than that of TPU. In addition, TPEE also has excellent low temperature resistance. The brittle point of TPEE is lower than -70℃, and the lower the hardness, the better the cold resistance. Most TPEE can be used for a long time at -40℃. Due to the balanced performance at high and low temperatures, TPEE has a very wide operating temperature range and can be used at -70-200℃.

●Chemical medium resistance

TPEE has excellent oil resistance and can withstand most polar liquid chemical media (such as acids, alkalis, amines and diol compounds) at room temperature. Its chemical resistance increases with the increase of its hardness. TPEE has good anti-swelling and anti-permeation properties for most organic solvents, fuels and gases, and its fuel permeability is only 1/3-1/300 of that of oil-resistant rubbers such as chloroprene rubber, chlorosulfonated polyethylene, and nitrile rubber.

● Weather resistance and aging resistance

TPEE has excellent chemical stability under various external conditions such as water mist, ozone, and outdoor atmosphere. Like most thermoplastic elastomers (TPE), it will degrade under the action of ultraviolet light (ultraviolet light below 310nm is a major factor in degradation). Therefore, for outdoor applications or products exposed to sunlight, ultraviolet light protection additives should be added to the formula, including carbon black and various pigments or other shielding materials. Phenolic antioxidants and benzotriazole-type ultraviolet light shielding agents can be used together to effectively prevent ultraviolet light aging.

● High resilience

The application of TPEE materials to springs can make the springs have a long service life and help trains start, accelerate, decelerate and stop smoothly. Unlike metal springs, it will not rust, deteriorate under natural environmental conditions, or cause elastic rupture and loss. Compared with rubber materials, it has greater reusability and can maintain good elasticity.

●Processing and molding

TPEE has excellent melt stability and sufficient thermoplasticity, so it has good processability and can be processed by various thermoplastic processing techniques, such as extrusion, injection, blow molding, rotational molding and melt casting. At low shear rates, TPEE melt viscosity is insensitive to shear rate, while at high shear rates, melt viscosity decreases as shear rate increases. Since TPEE melt is very sensitive to temperature, its melt viscosity changes several to dozens of times within a 10°C range, so the temperature should be strictly controlled during molding.

Conclusion

At present, there is no unified name for thermoplastic elastomers. It is customary to use English abbreviations. For the sake of uniformity, they are all called TPE or thermoplastic elastomer.

(1) TPE = TPR, which is the general term for all thermoplastic elastomers and thermoplastic rubbers. In China, it represents styrene elastomers;

(2) In the United States, Taiwan and other regions, styrene elastomers TPE (SBS, SEBS, SIS matrix) and dynamically vulcanized rubber TPV (EPDM + PP-X) are not classified and are collectively referred to as TPR.

(3) EPDM + PP elastomers belong to polyolefin elastomers, that is, TPV and TPO are the same concept;

(4) Differences between polyolefin elastomers TPV/TPO: a. Common points: TPO and TPV are both made of EPDM (polyolefin elastomer) + PP. b. Differences: TPO-polyolefin thermoplastic elastomer; TPV-dynamically vulcanized thermoplastic elastomer rubber; TPO is a simple physical blend (partially vulcanized, low degree of crosslinking), and TPV is fully vulcanized (dynamic micron-level segmented fully vulcanized, with a very high degree of crosslinking).

(5) TPU: wear-resistant, large stretch; poor elasticity, not resistant to acid, alkali, and oil. TPV: resistant to acid, alkali, oil, weather, and high temperature, UV resistance, best elasticity; poor stretch. TPE/TPR: mediocre performance in all aspects, the cheapest unit price.