Fluoro-Silicone-Rubbers (MFQ or FVMQ)
Nomenclature: MFQ according to ISO 1629 ("Rubber and latices – Nomenclature") or FVMQ according to ASTM 1418 ("Practice for Rubber and Rubber Latices — Nomenclature"); high temperature resistant up to +200°C and more, less resistant to chemical compunds and solvents than FPM, flexible at low temperatures. The polysiloxane-backbone can contain methyl-, vinyl- and flourine-functionalised side chains.
Fluorosilicones combine the high- and low-temperature properties of silicones with the resistance to oils and fuels of fluoropolymers. The fluorosilicones offer a larger service temperature range as the fluorocarbon elastomers (FKM’s). O-rings made of fluorosilicone are mainly used in high temperature fuel-systems in which silicone has to be resistant to dry heat. O-rings made of fluorosilicone can also be exposed to petroleum-based oils and/or hydrocarbon-containing fuels. By the utilisation of some oils and fuels it is recommended to reduce the maximum service temperature, because the decomposizion of the fluorosilcones, starting at 200°C, liberates acids which can attack on their part the material. In low-temperature domains the fluorosilicone o-rings can be used till –73°C. Due to the slight tensile-strength, the high friction coefficient and the unsatisfactory wastage properties, fluorosilicone o-rings are recommended in general only for static applications, however fluorosilicones with high tensile strength are also obtainable. Some of these compounds show an improved compression set rest. Many fluorosilicone-compounds possess an outstanding high shrinkage-rate. Due to the diversity of the fluorosilicones the fabrication-forms of the fluorsilicones differ from that of other fluorocarbon elastomers.
- aeronautical application
- high temperature resistant coolant tubes for trucks
- application involving resistance to fuels, oils and solvents