Phenolics are the result of polymerization between layers of paper, canvas, linen, or glass cloth impregnated with synthetic thermosetting resins. These industrial laminates are a popular alternative to acrylic, because of its high resistance to flexing.
The glass base material and resin (epoxy, melamine, polyimide. or silicone) combination used is dependent upon the intended application of the finished product. Physical strength, resiliency, ease and versatility of fabrication, and excellent electrical properties make phenolics useful as support components in a wide range of mechanical and electrical applications. Glass cloth is rated for flammability.
G-3 Glass Cloth / Phenolic Resin: Specified for good physical and electrical properties under dry conditions. Often used to replace asbestos in static applications. Certifies to NEMA G-3 per MIL-I-24768/18 GPG.
FR-4, G-10 Glass Cloth / Epoxy Resin: Specified for their extremely high strength and high dimensional stability over temperature. FR-4 is a fire-retardant. G-10 glass-epoxy laminate that is used primarily in the printed circuit board industry. Also available copper-clad (both sides), static dissipative (ESD material both sides). Certifies to NEMA FR-4, G-1o per Mil-I-24768/27 GEE-F.
FR-5, G-11 Glass Cloth / Epoxy Resin: Similar to G10/FR4, with the addition of a higher operating temperature and some improved mechanical strength at elevated temperatures. Certifies to Mil-I-24768/28 GEB–F.
G-5 and G-9 Glass Cloth / Melamine Resin: Melamines are the hardest of all laminates, exhibiting good dimensional stability and arc resistance. It is also caustic resistant. G-9 is recommended for humid environments. Melamine phenolics are available in sheet, rod, and tube forms. Certifies to NEMA G-5, G-9 per Mil-I-24768/1 CME.
G-7 Glass Cloth / Silicone Resin: This grade has excellent heat and arc resistance. It has extremely good dielectric loss properties under dry conditions and good electrical properties under humid conditions, although the percentage of change is high. Certifies to NEMA G-7 per Mil-I-24768117 GSG.
G-30 (aka Norplex P95-GPY) Glass Polyimide Garolite: Made of glass fabric with a polyimide resin binder. Capable of continuous long term use at 500°F and higher. Machining characteristics are similar to Grades G10 and G11. P95 complies with the requirements of IEC 60893-3-7-PI GC 301.
GPO-1 and GPO-3 Glass Cloth / Polyester: GPO-1 (tan) general purpose grade has good thermal electrical and mechanical properties. GPO-3 (red, black, white) offers superior arc and track resistance. Certifies to NEMA GPO-1 per MIL-I-24768/4; NEMA GPO-3 per MIL-I-24768/6 (GPO-3).
GPO-2 Glass Cloth / Polyester: Specified for applications where good flame resistance is required in addition to good electrical properties, physical properties, and heat resistance. GPO-2 is a UL recognized product. Produced in two standard colors, red and black. Certifies to NEMA GPO-2 per MIL-I-24768/5.