TPV generations
Thermoplastics > Polyolefins
Generation of vulcanized thermoplastic TPVs | ||||||||
First generation | ||||||||
The elastomers are classified according to DIN / ISO 1629, which derives from ASTM D 1418-79. This Norm divides synthetic rubbers into 5 groups, average shore hardness 20A ÷ 90A Group M, with saturated polyethylene chains EPDM, EPM, AEM, ACM, CM, CSM, FEPM, FFPM, FPM, FFKM, EVA, ACM, AEM, FEPM, FKM Group O, with oxygen in the polymer chain CO, ECO, AECO Group Q, with oxygen and silicon in the polymer chain FMQ, MQ, PMQ, PVMQ, VMQ Group R with the polymer chain containing unsaturated carbon BIIR, BR, IIR, CR, IR, NBR, SBR, CIIR, XNBR, HNBR, BIR, ECR, HCR, NR, LNR, ENR Group U, with carbon, oxygen and nitrogen in the polymer chain AU, UE, PU, PUR | ||||||||
Second generation | ||||||||
Vulcanized thermoplastics (TPVs) of second generation are classified, according to ISO 1043, with the abbreviation TPE (thermoplastic elastomers), at the end of the acronym TPE, a fourth letter is added that determines the chemical nature:
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Third generation | ||||||||
The third generation of TPVs, are very resistant to heat and oil as the second generation, but maintain the hardness of the first generation. They are obtained in two steps; by polymerization by impregnation of second generation TPVs (TPE-A, TPC-ET, TPE-S, TPE-U, TPE-V) with acrylate monomers, grafting and crosslinking them in the solid state. To obtain a good balance between the properties of the product, the processability and the production it is necessary to use hydrophobic butylacrylate in the first step and then ethylacrylate in the second step. | ||||||||
Fourth generation | ||||||||
In recent years, the fourth generation of TPVs, replacing EPM-co and EPDM-terpolymers with ethylene / octene copolymers (POE), and achieving the stage of dynamic cross-linking through the use of special catalysts. In particular applications, it is highly desirable to obtain improved resistance to oils, less oil absorption and increased chemical and abrasion resistance combined with a remarkable surface finish. The newly developed thermoplastic vulcanizates, composed of a thermoplastic polyurethane (TPU) matrix and a densely cross-linked rubber phase and ethylene-vinyl acetate (EVA) copolymer microdispersion, can guarantee such quality requirements. | ||||||||