In the printed circuit board process, the composition of the flexible coat plate was studied as an example of three-layer flexible cozy plate. It is carried out by a metal foil conductor, an insulating foil conductor, an insulating film, and an intermediate layer binder.  
 
Metal foil conductors typically have copper foil, aluminum foil, and crucible alloy foil. In general, flexible coat copies require good ductility and dynamic flexibility. The elongation elongation of the electrolytic copper foil is 4%, and the elongation elongation of the high elongation electrolytic copper foil and the transducer can reach 10%. In terms of fatigue toughness, the electrolytic copper foil is generally low, and the high toughness electrolytic copper foil is 10.25%, and the translucent copper foil is 150%. Therefore, in this regard, the most suitable method of using a translucent copper foil is a flexible plate. However, when there is a special requirement, electrolytic copper foil can also be used to reduce manufacturing cost, that is, the flexible plate does not require dynamic bending.  
 
The main insulating film has a polyester film, a polyimide film, a fluorocarbon film, and an aromatic polyamide paper. Currently, the first two are most common. The polyester film is used for the working conditions of the flexible plate below 105 ° C, and the common thickness is 25-125 um. It has good dielectric properties, chemical resistance and low hygroscopicity. However, both thermal resistance and dimensional stability are thermosetting polymers, with good dimensional stability and thermal stability. The main performance index of the film is: tensile elasticity, volume resistor coefficient, tensile strength, thermal expansion coefficient, dielectric constant, elongation elongation, breakdown voltage, surface resistance coefficient.  
 
The main interlayer binder has epoxy resin, acrylate resin, phenol modified polyvinyl butyral resin, polyester resin, polyimide resin, and the like. Epoxy resins and acrylic resins are two most common resins. The epoxy resin adhesive is high, and the dielectric properties are good, chemically corrosive. The process of the acrylate resin adhesive is superior to the epoxy resin binder, which has excellent flexibility, dielectric properties, and chemical resistance. The intermediate layer adhesive is mainly responsible for the adhesion of the conductive metal foil and the insulating film. It plays an important role in the heat resistance, chemical resistance and dielectric properties of flexographic version. It plays an important role in the heat resistance, chemical resistance, and dielectric properties of the flame retardant flexible plate. In flame retardant flexible coat copper, the adhesive also determines its flame retardancy. The general thickness of the adhesive coating is 12.5-40 um.  
 
Production process of flexible coated copper plate  
The three-layer method can be divided into two categories: sheet method and continuous method. Plate method is the same as the rigid coated copper production. It is achieved by rubber, suppression and other processes. The continuous method is to complete the manufacturing process of the product in the complexing machine. Its process flow is: gel coating drying and formulation, curing and shearing, flexible plate (also known as flexible plate), which is a very important performance. It is related to different thin film materials, different copper foil thicknesses and different manufacturing processes.