TPX™ (Polymethyl Pentene)
- Basic information
TPX™ is a 4-methylpentene-1-based olefin copolymer.
TPX™ has a unique molecular structure. Although TPX™ is a crystalline olefin polymer, it shows transparency. Because of its excellent heat resistance, release property and chemical resistance, TPX™ is used for industrial materials including mandrels and sheaths in the manufacture of high-pressure rubber hoses, mold cups for creating LED lights and other applications such as release film in the FPC manufacturing process and release paper in the manufacture of synthetic leather.
Furthermore, TPX™ possesses the lowest density among thermoplastic polymers, thereby providing the molded articles with lower weight. This leads to a reduction in the environmental load during transportation. It is also noted that TPX™ is a halogen-free polymer, which is denoted as an environmentally-friendly material.
TPX™ is also used for food-related applications such as food wraps, food preservation packs, baking cartons and microwave oven tableware.
TPX™ has a high melting point in the range from 220℃ to 240℃ and a high Vicat softening temperature. It can therefore be used for high temperature applications. However, as the heat distortion temperature of TPX™ is almost same as that of polypropylene, its application in a high-stress environment needs to be carefully considered.
Releasability and Non-compatibility
The surface tension of TPX™ (24mN/m) is very low, and this value is the second lowest compared to fluorine polymers. TPX™ therefore has excellent releasability against various materials. TPX™ is used as a release material in the hardening process of thermosetting resins (urethane, epoxy etc.). Furthermore, since TPX™ shows incompatibility with thermoplastic resins (PET, PP etc.), it is used to create a porous structure in PET or PP membranes.
Although TPX™ is a crystalline polymer, it exhibits excellent transparency (Haze: < 5 % ) and light transmittance. In particular, TPX™ is used for optical analysis cells because of its higher UV transmittance as compared to glass and other transparent polymers.
Because of its stable C-C bonds, TPX™ has better chemical resistance than polycarbonate and acrylic polymer. TPX™ shows excellent chemical resistance, particularly against acids, alkalis and alcohol.
For this reason, TPX™ is used in a range of applications that require chemical resistance, such as cosmetic container caps and tubes, experimental apparatus and analytical cells.
TPX™ has the characteristic of excellent gas permeability derived from its molecular structure. As a result, TPX™ is widely used for gas permeative applications such as gas separation membranes.
Low dielectric property
Since TPX™ has a non-polar structure, its dielectric property is almost same as fluorine polymers. It should be noted that dielectric property of TPX™ is hardly affected by frequency and TPX™ can be injection molded, unlike PTFE. TPX™ has a stable dielectric property in a broad frequency range.
The density of TPX™ is the lowest (830 kg/m3) among thermoplastic polymers, and its specific volume is larger than that of other transparent polymers. For this reason, it is possible to reduce the weight of injection-molded articles by using TPX™ or TPX™ compounds.
TPX™ has very low water absorbance, and therefore the dimensions of a TPX product are hardly affected by water absorbance. Furthermore, since TPX™ does not hydrolyze in boiling water, it can be used for experimental apparatus and animal cages that require steam sterilization.
Hygienic approved TPX™ grades (JPN standards, FDA regulations and EU regulations) are also available, and they are used for food wraps and microwave oven tableware.
Low refractive index
The refractive index of TPX™ is 1.463nD20, lower than fluorine polymers.