FR-4 is a code name for the grade of flame-retardant materials. It represents a material specification that the resin material must be able to extinguish by itself after the burning state. It is not a material name, but a material grade, so general circuit boards There are many types of FR-4 grade materials, but most of them are composite materials made of so-called Tera-Function epoxy resin, Filler and glass fiber.

The surface colors of FR-4 epoxy glass cloth laminate are:
Yellow FR-4, white FR-4, black FR-4, blue FR-4, etc.

FR-4 is a substrate used in PCB, and it is a type of sheet material. According to different reinforcement materials, the sheet materials are mainly classified into the following four types:

1) FR-4: Glass cloth substrate
2) FR-1, FR-2, etc.: paper substrate
3) CEM series: composite substrate
4) Special material substrate (ceramic, metal base, etc.) FR-4 is a laminate product made of special electronic cloth impregnated with epoxy phenolic resin and hot pressed at high temperature and high pressure.

Features: It has high mechanical properties and dielectric properties, good heat resistance and moisture resistance, and good machinability.

Uses: Used as insulation structural parts in motors and electrical equipment, including various types of switches, FPC reinforced electrical insulation carbon film printed circuit boards, computer drilling pads, mold fixtures, etc. (PCB test racks), and can be used in humid environments and Used in transformer oil.