1, TPEE
Thermoplastic polyester elastomer referred to as TPEE or COPE, is a class containing PBT (polybutylene terephthalate) polyester hard segments (crystalline phase) and aliphatic polyester or polyether (amorphous phase) soft segments of the linear block *** polymer. tpee belongs to the high-performance engineering-grade elastomers with High mechanical strength, good elasticity, impact resistance, creep resistance, cold resistance, bending fatigue resistance, oil resistance, resistance to chemicals and solvents, etc., with good processability, and can be filled, reinforced and alloying modification, in the automotive parts, hydraulic hoses, cables and wires, electronic and electrical appliances, industrial products, stationery and sporting goods, biological materials, etc., have been widely used.
TPEE physical and chemical properties
●Mechanical properties By adjusting the ratio of soft and hard segments, the hardness of TPEE can vary from Shore D32 to D80, and its elasticity and strength are between rubber and plastic. Compared with other thermoplastic elastomers (TPEs), TPEE modulus is higher than other TPEs of the same hardness under low strain conditions. When modulus is an important design condition, the cross-sectional area of the product can be reduced with TPEE, reducing the amount of material used.
●Tensile strength Compared with polyurethane elastomers (TPU), TPEE compression modulus and tensile modulus are much higher, using the same hardness of TPEE and TPU to make the same part, the former can withstand greater loads. Above room temperature, TPEE bending modulus is very high, suitable for the production of cantilever beams or torque-type parts, especially suitable for the production of high temperature parts.TPEE low-temperature flexibility is good, low-temperature notched impact strength is better than the other TPE, abrasion resistance is comparable with TPU.TPEE has excellent fatigue resistance, and high elasticity characteristics combine to make the material become an ideal material for multiple cyclic loading conditions of use, suitable for It is suitable for making gears, rubber rollers, flexible couplings, belts and so on.
●Heat-resistant performance TPEE has excellent heat-resistant performance, the higher the hardness, the better the heat resistance.TPEE's use temperature is very high, can adapt to the automotive production line baking paint temperature (150-160 ℃), and it is at high temperatures with little loss of mechanical properties. Used above 120 ℃, TPEE tensile strength is much higher than TPU.In addition, TPEE also has excellent low temperature resistance.TPEE brittle point is lower than -70 ℃, and the lower the hardness, the better the cold resistance, most of the 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 media resistance TPEE has excellent oil resistance, at room temperature can resist most polar liquid chemical media (such as acids, alkalis, amines and diol compounds), and its ability to resist chemicals with its hardness increases.TPEE on most organic solvents, fuels and gases have good resistance to swelling performance and anti-permeability, and the permeability of fuel oil is only chloroprene, chlorosulfonated polyethylene, nitrile rubber and other oil-resistant rubber, such as chloroprene, chlorosulfonated polyethylene, nitrile rubber. The permeability of TPEE to fuel is only 1/3-1/300 of chloroprene, chlorosulphonated polyethylene, nitrile rubber and other oil-resistant rubbers.
●Weathering and aging resistance TPEE has excellent chemical stability under various external conditions, such as water spray, ozone, and outdoor atmosphere. Like most thermoplastic elastomers (TPE), degradation occurs under the action of ultraviolet light (310nm below the ultraviolet light is a major factor in degradation), so for outdoor applications or products subjected to sunlight irradiation conditions, the formula should be added to the UV protection additives, which include carbon black and a variety of pigments or other shielding materials, phenolic antioxidant and benzotriazole-type UV shielding agent and use, can be effectively play the anti-ultraviolet aging.
●High Resilience Applying TPEE materials to springs gives them a long service life and helps trains start, accelerate, decelerate, and stop smoothly. Unlike metal springs, they do not rust, deteriorate under natural environmental conditions, or suffer from elasticity cracking or loss. Compared to rubber materials, they have greater reusability and maintain excellent elasticity.
●Processing and molding TPEE has excellent melt stability and full thermoplasticity, so it has good processability, and can be processed using a variety of thermoplastic processing techniques, such as extrusion, injection, blow molding, rotational molding and melt casting molding. In low shear rate, TPEE melt viscosity is not sensitive to shear rate, while in high shear rate, melt viscosity with the shear rate increases and decreases. Due to the TPEE melt is very sensitive to temperature, in the range of 10 ℃ change, its melt viscosity changes several times to dozens of times, so the molding should be strictly controlled temperature.
2, TPU
Polyurethane thermoplastic elastomer (TPU), also known as polyurethane rubber, belongs to a class of elastic polymer materials containing more urethane groups in the molecular chain (-NHCOO-). It is produced by the interaction of oligomeric diisocyanates with polyether or polyester polyols with terminal hydroxyl groups and low molecular weight diol chain growth agents. Polyurethane elastomers are block polymers, generally consisting of a flexible long chain of polyols to form the soft segment and a diisocyanate and chain extender to form the hard segment. Hard segments and hard segments alternate with each other in an orderly arrangement, forming a repeating structure of crystalline units, giving the elastomer with high strength, rigidity and melting point and other properties; soft segments are disordered curly arrangement, forming an amorphous zone, giving the elastomer with flexibility, elasticity, hygroscopicity and low-temperature resistance properties. Polyurethane elastomer molecular chain contains a large number of ammonia ester groups and ether, ester and urea groups, with strong hydrogen bonding. Formulations generated from a large number of ethers and esters can yield polyurethane elastomer varieties with very different properties. These structural features give polyurethane elastomers excellent abrasion resistance, toughness and high elasticity, as well as easy compatibility with other polymers. (A) the performance of polyurethane thermoplastic elastomers
(1) TPU formation and combination of diversity, a wide range of varieties, there are mixing, casting and thermoplastic type, the chemical structure is also more complex, and the performance of different, such as polyester-type TPU high mechanical properties, good oil resistance, but poor water resistance; polyether-type TPU low temperature resistance and water resistance is better than polyester-type, but the oil resistance, mechanical properties than the polyester-type poorer. Polyester type TPU. In general, all have good physical properties, its performance between the general rubber and thermoplastics, TPU is generally divided into compounding, casting and thermoplastic.
(2) TPU is a block **** polymer, hard section and soft section of the component ratio determines the performance of TPU. Hard segment has a special role in the modulus, hardness and tear strength, while the soft segment mainly affects the elasticity of the product and low temperature performance.TPU has excellent softness and resilience, can be from very soft to very hard, from very good flexibility to rigidity is very large, or from the hydrophilic type that can absorb moisture to the water-repellent hydrophobic type, and a wide range of hardness (Shore A10-D75) to maintain high elasticity, in the same hardness It has a high elasticity in a wide range of hardness (Shore A10-D75) and has a higher load-bearing capacity than other elastomers at the same hardness.
(3) TPU has excellent abrasion resistance, its abrasion resistance is 2-10 times that of natural rubber; elongation at break is as high as 600% to 800%, 300% higher than natural rubber.
(4) TPU impact strength is relatively high, the density of 1.14-1.22g/cm3, tensile strength of 30-65MPa, ester TPU is slightly higher than ether TPU; thermal performance is also high, long-term use of temperature in the -50-90 ℃ temperature but also shows its good soft elasticity.
(5) TPU chemical resistance, oil resistance, radiation resistance, oxygen resistance, ozone resistance, fatigue resistance and vibration resistance is good, heat resistance is also relatively high, and molding and processing costs are low.
(6) Compared with metal materials, TPU products have the advantages of light weight, low noise, abrasion resistance, low processing costs and corrosion resistance; compared with plastics, TPU has the advantages of non-brittle, elastic memory, wear-resistant; compared with rubber, TPU has the advantages of abrasion resistance, cut-resistant, tear-resistant, high load-bearing capacity, can be potting, pouring, and a wide range of hardness.
(7) TPU weathering is relatively poor, in the sunlight is prone to aging degradation, so in the processing should be added antioxidants and light stabilizers.
3.TPV
Thermoplastic Vulcanizate (Thermoplastic Vulcanizate), referred to as TPV, thermoplastic vulcanizate rubber in Chinese referred to as thermoplastic rubber (Thermoplastic Rubber in English), referred to as TPR, but the name is easy to and other types of TPE phase But this name is easily confused with other kinds of TPE, because usually thermoplastic elastomers are also called thermoplastic rubber, especially styrenic elastomers, at least in China at present, it seems that "TPR" has become its proprietary name, the mention of TPR, it is to refer to SBS, SEBS, and other styrenic elastomers as the base material of thermoplastic elastomers, which is the same as the consumption of styrenic elastomers in the field of civil as well as end consumer goods. This is due to the fact that styrenic elastomers are consumed in both civilian and consumer applications.
Thermoplastic vulcanized rubber name if say a little more detailed, it should be thermoplastic dynamic vulcanized rubber (English for Thermoplastic Dyamic Vulcanizate), added "dynamic" 2 words is more specific to the production of this thermoplastic vulcanized rubber process --- dynamic vulcanization, this process is more specific to the production of this thermoplastic vulcanized rubber. --Dynamic vulcanization, this process refers to the rubber and thermoplastic melt **** mixing process to make the rubber vulcanization, of course, in the rubber in the vulcanization at the same time also continuously mixed with the thermoplastic, so the vulcanized rubber is as a dispersed phase distributed in the thermoplastic continuous phase. The corresponding thermoplastic static vulcanized rubber, is the rubber according to the traditional method of vulcanization, and then through the milling equipment to vulcanize the rubber into powder, and finally mixed with molten thermoplastic ****, theoretically, this method can also produce excellent performance of the TPV, but so far, just in the laboratory stage.
Composition
TPV is mainly composed of two parts, one is plastic, as a continuous phase, and the other is rubber as a dispersed phase. Usually the rubber needs to be combined with a softening oil or plasticizer with it. Vulcanizing agent and some auxiliary additives are also essential. In addition, in order to reduce the cost or improve the performance of a certain aspect, some inorganic fillers will be filled.
Specific properties
1, good elasticity and compression deformation resistance, environmental resistance, aging resistance is equivalent to EPDM, while its oil and solvent resistance is comparable to general-purpose chloroprene rubber.
2, the application of a wide range of temperatures (- 60-150 ℃), the application of a wide range of soft hardness (25A-54D), easy to color the advantages of greatly improving the freedom of product design.
3, excellent processing performance: can be injected, extrusion and other thermoplastic processing methods, high efficiency, simple and easy to implement, without the need to add equipment, high mobility, shrinkage rate is small.
4, green, recyclable, and repeated use of six performance without significant decline, in line with EU environmental requirements.
5, the specific gravity is light (0.90-0.97), the appearance of the quality of uniformity, high surface grade, feel good.
Based on the above performance characteristics, TPV in a wide range of applications and traditional rubber materials, other TPE elastomers (including TPR \ SBS, SEBS, TPU, etc.) materials or PVC and other plastic materials compared to the comprehensive performance and comprehensive cost have a certain degree of substitution advantages, so as to provide products for the enterprise product innovation, enhance the added value of the product, improve competitiveness This provides a new choice for product enterprises in product innovation, enhance product value-added, and improve competitiveness.
A, automobile airbag deployment door. Hytrel has been recognized as the best material at home and abroad.
B. Hydraulic hoses. Hytrel is used for both the inner and outer layers, and the extruder screw is a gradual transition screw with equal pitch and high compression ratio (2.7/1 to 4/1).
C, industrial wheels. Wear-resistant, lightweight.
D, flexible coupling joints: wear-resistant, low heat generation under high load and high torque.
E, fire hose inner layer rubber: hydrolysis resistance, mold resistance, fatigue resistance are excellent.
F, cross-country skiing boot sole: good low-temperature flexibility, fatigue resistance.
G. Automobile dust cover
Mid-range dust cover (e.g. rack dust cover) adopts EPDM TPV (e.g. Santoprene), and mid-range and high-grade dust cover (e.g. CVJ) adopts TPEE (e.g. Hytrel). Tianjin Huan Yu company with imported production equipment has been mass production.
Only TPEE with 47D hardness can reach the mechanical properties of Volkswagen and Delphi (Delph) dust cover. Production process: injection a blow molding, equipment and TPV dust cover the same.TPEE injection molding must be strictly controlled before the moisture content (<0.1%) injection a blowing operation, the temperature sensitivity of TPEE than the TPV up to, to pay more attention.
Currently China's rubber industry to use the largest amount of TPEE products is the automotive dust cover, but the relative amount is still not large. According to DuPont: Japan's Shuehiro company from the traditional silicone rubber to Hytrel to make the remote control buttons, thus shortening the production cycle, enhance the flexibility of the design, quite "ideal". If this technology is popularized, the amount of TPEE will be greatly increased.