FEP (Fluorinated ethylene propylene) Introduction
FEP-fluorinated ethylene propylene copolymer
FEP is tetrafluoroethylene and hexafluoropropylene copolymerization, also known as F46.
FEP has a melting point of 580F and a density of 2.15g / cc. It is a soft plastic with lower tensile strength, wear resistance and creep resistance than many engineering plastics. It is chemically inert and has a low dielectric constant (2.1) over a wide range of temperatures and frequencies. The material does not ignite, can prevent the spread of the flame. It has excellent weatherability, low coefficient of friction, can be used from low temperature to 392F. This material can be made into granular products for extrusion molding and molding, as fluidized bed and electrostatically coated powders, as well as aqueous dispersions. Semi-finished film, board. Stick and single fiber.
Its main purpose is to use the inner village, drum surface and various wires and cables used to make pipes and chemical equipment such as aircraft hook lines, booster cables, alarm cables, flat cables and well logging cables. FEP membranes have been seen as thin coatings for solar collectors.
Poly FEP FEP or F46, is a copolymer of tetrafluoroethylene and hexafluoropropylene, hexafluoropropylene content of about 15%, is a modified PTFE material.
F46 resin has both similar properties and PTFE, but also has good processing properties of thermoplastics. Therefore, it makes up for the lack of PTFE processing difficulties, making it a substitute for PTFE material, widely used in wire and cable production of electronic equipment used in high temperature and high frequency transmission wire, computer internal connection cable, Aerospace wires and their special purpose installation line, pump cables and submersible motor winding wire insulation.
According to the processing needs, F46 can be divided into pellets, dispersions and paint three. Among them, the pellets according to their different melt index for molding, extrusion and injection molding; dispersion for impregnation sintering; paint for spraying and so on.
1. Poly FEP structural features
F46 resin is the same fluoropolymer structure as polytetrafluoroethylene, except that some of the fluorine atoms in the F46 main chain have been replaced by trifluoromethyl (-CF3). Both F46 resin and polytetrafluoroethylene are made of fluorocarbon Elemental composition, surrounded by carbon atoms completely surrounded by fluorine atoms, but F46 its macromolecules in the main chain branches and side chains. This structural difference has no significant effect on the upper temperature range of the material under long-term stress, with the F46 maximum temperature of 200 ° C and the polytetrafluoroethylene maximum temperature of 260 ° C. However, this structural difference, but F46 resin has a fairly definite melting point, and can be used in general thermoplastic processing molding process, making the process greatly simplified. This is PTFE does not have. This is the main purpose of using hexafluoropropylene to modify polytetrafluoroethylene.
The result, the domestic F46 resin melting point mostly in the 250-270 ℃, lower than the polytetrafluoroethylene.
F46 resin is a kind of crystalline polymer, its crystallinity is lower than that of polytetrafluoroethylene. When the F46 melt slowly cools below the melting point of the crystal, the macromolecule re-crystallizes with a crystallinity of 50% -60% When the melt is rapidly cooled by quenching, the crystallinity is small, between 40% and 50%. F46 crystal structure, are spherulitic structure, and resin and processing temperature and heat treatment methods have some differences. The company is located in:
2. Electrical insulation performance
F46's electrical insulation and PTFE are very similar. Its dielectric coefficient from cryogenic to maximum operating temperature, from 50Hz to 1010Hz UHF wide range of almost unchanged, and low, only about 2.1. The dielectric loss tangent varies somewhat with frequency but not with temperature.
The volume resistivity of F46 resin is very high, generally greater than 1015.m, with little change in temperature and is not affected by water and moisture. Arc resistance greater than 165s.
The breakdown field of F46 increases with the decrease of the thickness. When the thickness is more than 1mm, the breakdown field strength is above 30KV / mm, but it does not change with the temperature.
3 thermal performance
F46 resin heat resistance second only to PTFE, in the -85 ~ +200 ℃ temperature range of continuous use. Even at -200 ℃ and +260 ℃ under the limit, its performance does not deteriorate, you can use a short time. The company is located in:
The thermal decomposition temperature of F46 resin is higher than the melting point, and significant thermal decomposition occurs above 400 ℃. The decomposition products are mainly tetrafluoroethylene and hexafluoropropylene. Due to the F46 macromolecules often have isomers with the melting point above the end of the temperature will be decomposed, so more than 300 ℃ processing must also pay attention to proper ventilation. F46 is fairly stable below the melting point, but has a greater loss of mechanical strength at 200 ° C. The increase in melt index can be used to analyze the decrease in melt viscosity and the thermal decomposition of the copolymer.
F46 at -250 ℃ still not completely hard and brittle, but also to maintain a small elongation and a certain flexibility, even better than PTFE, is all other types of plastic below.
4. Chemical resistance
F46 chemical resistance and PTFE similar, with excellent chemical resistance. In addition to the high temperature of the fluorine element, molten alkali metal and chlorine trifluoride react, and other chemical contact are not corrosive.
5 mechanical properties
F46 compared with PTFE, hardness and tensile strength slightly increased, the friction coefficient is slightly larger than that of PTFE. F46 has better creep resistance at room temperature, but when the temperature is higher than 100 ℃, creep resistance is less than that of PTFE.
6. Other properties
F46 resin in the atmosphere oxidation resistance is very good, high atmospheric stability. F46 radiation resistance is better than polytetrafluoroethylene, slightly inferior to polyethylene. In air and room temperature, F46 began to show the performance of the minimum absorption dose of 105-106rad (ie 103-104Gy), it can be used as radiation-resistant materials.