Pertinax, the brand name is ( phenolic ) for a fiber composite material made ​​of paper and a phenol -formaldehyde resin. This so-called laminated paper is used in electrical engineering and electronics as insulating and insulating carrier material for electronic components and printed circuits, mainly in the form of printed circuit boards ( PCBs ). The density of Pertinax is approximately 1.35 to 1.36 g/cm3.

Pertinax (see also hard tissue ) evaporate always small amounts of phenol and formaldehyde, which not only produces a strong odor, but also in the mechanical working is a health hazard.

Characteristics of PCB base materials: FR1 = phenolic resin paper (cheap variety) FR2 = phenolic resin paper ( standard quality )

FR3 = epoxy resin paper FR4 = epoxy resin fiberglass fabric FR5 = epoxy resin fiberglass cloth ( heat-resistant )

Fiberglass fabric has the disadvantage that one hand while drilling a fine glass dust is generated, which can be hazardous to health, and on the other hand wear out tools faster. Therefore, the machining is performed with carbide or diamond tools.

Fiber - phenolic resin composite materials are also used for heat shields, because they form a protective layer of coke under extreme thermal stress.