FR-2 (Flame Resistant 2) is a

NEMA The National Electrical Manufacturers Association (NEMA) is the largest trade association of electrical equipment manufacturers in the United States. Founded in 1926, it advocates for the industry and publishes standards for electrical product ...

designation for synthetic resin bonded paper, a

composite material A composite or composite material (also composition material) is a material which is produced from two or more constituent materials. These constituent materials have notably dissimilar chemical or physical properties and are merged to create a ...

made of

paper Paper is a thin sheet material produced by mechanically or chemically processing cellulose fibres derived from wood, Textile, rags, poaceae, grasses, Feces#Other uses, herbivore dung, or other vegetable sources in water. Once the water is dra ...

impregnated with a plasticized

phenol formaldehyde resin Phenol formaldehyde resins (PF), also called phenolic resins or phenoplasts, are synthetic polymers obtained by the reaction of phenol or substituted phenol with formaldehyde. Used as the basis for Bakelite, PFs were the first commercial syntheti ...

, used in the manufacture of

printed circuit board A printed circuit board (PCB), also called printed wiring board (PWB), is a Lamination, laminated sandwich structure of electrical conduction, conductive and Insulator (electricity), insulating layers, each with a pattern of traces, planes ...

s. Its main properties are similar to NEMA grade XXXP (MIL-P-3115) material, and can be substituted for the latter in many applications.

Applications

FR-2 sheet with copper foil lamination on one or both sides is widely used to build low-end

consumer electronics Consumer electronics, also known as home electronics, are electronic devices intended for everyday household use. Consumer electronics include those used for entertainment, Communication, communications, and recreation. Historically, these prod ...

equipment. While its electrical and mechanical properties are inferior to those of epoxy-bonded fiberglass,

FR-4 FR-4 (or FR4) is a NEMA grade designation for glass-reinforced epoxy laminate material. FR-4 is a composite material composed of woven fiberglass cloth with an epoxy resin binder that is flame resistant (''self-extinguishing''). "FR" stands for ...

, it is significantly cheaper. It is not suitable for devices installed in vehicles, as continuous vibration can make cracks propagate, causing hairline fractures in copper circuit traces. Without copper foil lamination, FR-2 is sometimes used for simple structural shapes and electrical insulation.

Properties

Fabrication

FR-2 can be machined by drilling, sawing, milling and hot punching. Cold punching and shearing are not recommended, as they leave a ragged edge and tend to cause cracking. Tools made of high-speed steel can be used, although

tungsten carbide Tungsten carbide (chemical formula: ) is a carbide containing equal parts of tungsten and carbon atoms. In its most basic form, tungsten carbide is a fine gray powder, but it can be pressed and formed into shapes through sintering for use in in ...

tooling is preferred for high volume production. Adequate ventilation or respiration protection are mandatory during high-speed machining, as it gives off toxic vapors.

Trade names and synonyms

* Carta * Haefelyt * Lamitex * Paxolin, Paxoline * Pertinax, taken over by Lamitec and Dr. Dietrich Müller GmbH in 2014 * Getinax (in the Ex-USSR) *

Phenolic paper Phenolic paper is a material often used to make printed circuit board (PCB) substrates (the flat board to which electronic components and traces are attached). It is a very tough board made of wood fibre and phenolic polymers. It is most commonl ...

* Preßzell * Repelit * Synthetic resin bonded paper (SRBP) * Turbonit * Veroboard * Wahnerit

Applications

Properties

Fabrication

Trade names and synonyms

See also

References

Further reading