Glass Epoxy is a composite material that consists of glass fabric and epoxy resin. The sheet of composite material is cladded with 1/3oz, 1/2oz, 1oz, 2oz or 3oz of copper on single-side or double-sides.
The laminate most commonly used in printed circuit boards (PCBs) is a glass fiber reinforced (fiberglass) epoxy resin with a copper foil bonded on to one or both sides. This glass fiber epoxy laminate called as FR-4 Laminate or FR-4 CCL.
What’s the Glass in FR-4 Laminate?
Fiberglass yarns consist of a defined number of electronic fiberglass (E-Glass) filaments of a certain nominal diameter (generally 4-9μm), brought together to form a yarn. The structure of the yarn is fixed and protected by a size and a slight twist, generally in Z-direction. E-glass fiberglass yarns then are used to make glass fabrics, which excel in electric insulation, heat resistance, tensile strength, and dimensional stability.
What’s Exact Epoxy Resin?
Epoxy resins may be reacted (cross-linked) either with themselves through catalytic homopolymerisation, or with a wide range of co-reactants including polyfunctional amines, acids (and acid anhydrides), phenols, alcohols and thiols (usually called mercaptans). These co-reactants are often referred to as hardeners or curatives, and the cross-linking reaction is commonly to as curing.
Reaction of polepoxies with themselves or with polyfunctional hardeners forms a thermosetting polymer, often with favorable mechanical properties and high thermal and chemical resistance. Epoxy has a wide of applications, including metal coatings, use in electronics/electrical components/LEDs, high tension electrical insulators, and etc.
The health risks associated with exposure to epoxy resin compounds include contact dermatitis and allergic reactions, as well as respiratory problems from breathing vapor and sanding dust, especially when not fully cured.
Glass epoxy has a low coefficient of thermal expansion (CTE), and outstanding electrical properties. The performance characteristics mainly are:
- Flame retardant
- Strong and stiff
- Dimensionally stable
- Outstanding electrical properties
- Creep resistance
Except for used for PCB base material, glass epoxy can also be used for:
- Insulators for electromechanical devices
- Jigs and fixtures
- High strength composite parts