1. Definition of thermoplastic elastomer
Thermoplastic Elastomer (English Thermoplastic Elastomer) is an environmentally friendly low-carbon composite material with rubber properties (high elasticity, compression set, etc.) and plastic processing characteristics (simple process). (Popular oral: thermoplastic elastomer is a kind of rubber with high elasticity, high resilience, and can be injection-processed. It has environmental protection, non-toxic safety, wide hardness range, excellent coloration, soft touch and weather resistance. Anti-fatigue and temperature resistance, excellent processing performance, no need for vulcanization, can be recycled to reduce costs, can be double-molded, coated with PP, PE, PC, PS, ABS and other base materials, or can be molded separately .)
Due to historical and usage habits, there is no uniform naming of thermoplastic elastomers at home and abroad. In most regions, the English abbreviation TPE is collectively referred to as thermoplastic elastomer.
2. Distinction of thermoplastic elastomers
There are many types of thermoplastic elastomers TPE. The types we contact are TPE, TPR, TPU, TPV. Do you think it is very messy? The following explains the relevant knowledge:
First of all, TPE has such a meaning, that is, a general term for all thermoplastic elastomers, including TPR, TPU, TPV, TPEE, TPO, TPAE, and the like. Chinese is called Thermo-PlasticElastomer.
Usually, the user or the TPE we say is often referred to as a SEBS-based blended modified thermoplastic elastomer. The TPE of the SEBS system has a hardness range of 0 to 95 A and is transparent or natural particles. The burning flame is yellow, yellow or yellow, and the smoke is light and has a fragrant smell.
But in fact, when users encounter TPE, we should choose a suitable TPE type according to his specific requirements, instead of subjective understanding of the TPE of a specific SEBS system.
TPR, this is the name of users in Taiwan and even in Asia. The first person used SBS synthetic modification to make a rubber, but this rubber is thermoplastic, meaning "Thermo-plastic rubber" in English, abbreviated as TPR. After that, the SBS family appeared high-performance material SEBS, which was blended and modified, and the manufacturer called TPE to distinguish it from the SBS-modified TPR. However, many users (especially in Taiwan and Asia) still use the term TPR, but do not pay much attention to the differences in SEBS and SBS materials. In fact, there are some performance differences between TPE (TPR) of SEBS and SBS systems. TPR (based on the above analysis, in a sense with TBS of SEBS as a material) looks transparent or white particles with a hardness of 0~95A.
TPV is a blended dynamic vulcanized elastomer of PP and EPDM. TPV can be regarded as a kind of TPO, but it is given its excellent comprehensive performance due to its special dynamic vulcanization system (TPV has better solvent resistance, high temperature resistance and mechanical strength than TPE of TBS system, TPR). . TPV is currently the most successful and widely used rubber-plastic blend elastomer, so TPV is listed separately. The application of TPV in the automotive industry will be optimistic in the industry. TPV burns the petroleum odor of polypropylene PP, and its appearance is yellow or light yellow particles, usually ranging from 50 to 100A.
TPU, thermoplastic polyurethane. It is made by mixing MDI containing NCO functional group and POLYOL and 1.4BG containing OH functional group by kneading. It has good elasticity, good physical properties and various mechanical strengths. Therefore, it is widely used in injection, extrusion, calendering and dissolving into a solution type resin. It is a plastic material often used by plastics manufacturers, and its products cover a range of industrial applications and civilian necessities. The appearance of TPU is transparent particles with a hardness of 65A~80D. The burning has a special smell and has a sizzling sound.
1. What is SEBS Elastomer?
SEBS is a linear tri-doped copolymer in which an ethylene-butene copolymer obtained by hydrogenating polybutadiene is an intermediate elastic block in which polystyrene is an end portion. SEBS contains no unsaturated and double bonds and therefore has good stability and aging resistance.
2. Use of SEBS
(1) SEBS has good UV stability, oxidation resistance and thermal stability, so it can also be used in roofing and road asphalt.
(2) There is a good compatibility between SEBS and paraffin, so it can be used as a more flexible surface coating for paper products.
(3) SEBS is not sensitive to temperature when heated without significant shear flow, so it can be used as a template for IPN. (The basic principle of IPN: two immiscible polymers, which can achieve the interpenetration of entangled segments. For example, the two immiscible polymers can be "locked together" by covalent bond crosslinking.)
(4) The organic solution of SEBS oil blend can replace the natural latex to manufacture surgical gloves and other products. Since SEBS does not contain unsaturated double bonds and has high purity, it has the following two advantages:
Good anti-oxidation and ozone resistance;
Natural rubber contains protein that can cause dangerous allergic reactions in some patients, and this blend does not.
3, the specific performance of SEBS
SEBS has excellent aging resistance, both plasticity and high elasticity. It can be processed without vulcanization. The scraps can be reused. It is widely used in the production of high-grade elastomers, plastics, adhesives, lubricants, tackifiers and wires. Cable filler and sheathing materials; SEBS series are mainly used for plastic modified, soft baby toys and other high-elastic transparent rubber products. SEBS has good weather resistance, heat resistance, compression set resistance and excellent mechanical properties:
(1) Better temperature resistance, the embrittlement temperature is ≤ -60 ° C, the maximum use temperature is 149 ° C, and the decomposition temperature is greater than 270 ° C under an oxygen atmosphere.
(2) Excellent aging resistance, the performance degradation rate is less than 10% in the artificial accelerated aging chamber for one week, and the performance degradation is less than 10% in the ozone aging (38 °C) for 100 hours.
(3) Excellent electrical properties, the dielectric constant is 1.3*10-4 at one kilohertz, 2.3*10-4 at one megahertz; the volume resistance is 9*1016 Ω/cm in one minute; 2*1017 Ω/cm in two minutes.
(4) Good solubility, blending properties and excellent oil-filling properties, soluble in many common solvents, solubility parameters between 7.2 and 9.6, can be blended with various polymers, can be used in the rubber industry commonly used oils Fill the oil, such as white oil or naphthenic oil.
(5) Elastomers that can be used without vulcanization. The processing properties are similar to those of SBS. The scraps can be reused, meet environmental requirements, are non-toxic, and meet FDA requirements.
(6) The lighter weight is about 0.91, and the same weight can produce more volume of products.