FPC connector copper foil is suitable for use in flexible circuits. It can be electrodeposited or plated. One side of the copper foil prepared by electrodeposition is glossy, while the other side is dull and lusterless. It is a flexible material and can be made into many thicknesses and widths. The matt side of ED copper foil is often treated specially to improve its adhesion.
- Insulating film
There are many kinds of insulating film materials for FPC connectors, but the most commonly used are polyimide and polyester materials. At present, nearly 80% of all flexible circuit manufacturers in the United States use polyimide film materials, and about 20% use polyester film materials. Polyimide materials are non flammable, with stable geometric dimensions, high tensile strength and the ability to withstand welding temperature. Polyester, also known as polyethylene diphenylene dicarboxylate, is similar to polyimide in physical properties. It has low dielectric constant, absorbs little moisture, but is not resistant to high temperature. The melting point of polyester is 250 ℃, and the glass transition temperature (Tg) is 80 ℃, which limits their use in applications requiring a large number of end welding. They are rigid in cryogenic applications. Nevertheless, they are suitable for use on products such as telephones and other products that do not need to be exposed to harsh environments.
In addition to bonding the insulating film to the conductive material, the adhesive can also be used as a covering layer, a protective coating, and a covering coating. The main difference between the two is the application mode used. The covering layer is bonded to cover the insulating film to form a circuit with a laminated structure. Screen printing technology used for covering and coating adhesive.