The most popular of the rigid reinforcements for printed wiring boards is woven E-glass (electrical-grade glass) fabric. These fabrics are constructed to meet weight, thickness, strength, and cost objectives. The woven fabric is used in many industries as reinforcements for thermoplastic and thermosetting plastic parts. Thermosetting laminates are particularly enhanced by the properties of the glass fabric. Organic resins such as epoxy, phenolic, polyester, cyanate ester, and polyimide are low-strength and often brittle synthetics, but when reinforced with glass they are used to produce parts with superior durability, high-strength, and excellent insulating properties
