Calendered copper foil Classification of ：
1. It can be divided into optical foil and processed foil according to production and processing methods
Gloss foil is a product after cold rolling/annealing, degreasing, anti-oxidation treatment, cutting and packaging in the production process, and its surface is not electroplated.
The foil is treated by electroplating on the basis of light foil, reddening (red treatment, usually copper plating roughening), blackening (black treatment, usually fine roughening of copper nickel alloy), ashing (usually nickel alloy electroplating, zinc plating, chromate passivation, silane treatment, etc.) and oxidation resistance treatment (generally zinc and NiCr alloy layers are plated first, then a layer of organic silane is dipped), cutting.
2. Press texture of material Divided into High flexibility calendered copper foil and High strength rolled copper alloy foil 。
Highly flexible calendered copper foil: By changing the rolling process conditions, the recrystallization structure of the rolled copper foil presents a well developed cubic he structure, the grain boundary dip angle is small, and the grain size is coarse. The flexibility of the rolled copper foil with this structure is greatly improved, and the bending times are 4 times higher than that of ordinary rolled copper foil.
High strength calendered copper foil: By adding alloying elements in the copper smelting and casting process, the ingot is alloyed and the strength of the rolled copper foil is improved. Through proper alloying, the electrical conductivity of rolled alloy foil is controlled above 90% IACS, the strength is several times higher than that of ordinary rolled copper foil, and the hot state is stable.
Rolling mill is Production of calendered copper foil As one of the main core equipment, the selection of rolling mill is usually strict. Aluminum foil rolling is characterized by strict control requirements for the thickness control system, tension, speed, cooling and lubrication of the rolling mill. Therefore, the rolling mill is required to have high rigidity and precise structure, and the roll diameter should be minimized. At present, 20 high or 18 high rolling mills are used for aluminum foil rolling in Europe and America, and X type 6-high rolling mills are usually used for aluminum foil rolling in Japan. In actual production, for ultra-thin products (thickness<50 μ m), the industry tends to use X-type 6-high mill or 18 high mill for production.
The surface treatment of rolled copper foil can be carried out as follows:
(1) Roughening and curing treatment: the surface of the rolled copper foil needs to be roughened, mainly because the surface of the rolled copper foil is very smooth, the surface roughness is generally only about 1 μ m, and the untreated copper foil surface can hardly be pressed with resin. Therefore, in order to improve the adhesion between the copper foil and the substrate, a layer of spherical grains is plated on the surface of the copper foil to increase the surface roughness of the copper foil.
(2) Heat resistant layer treatment: the main function of heat resistant layer treatment is to form an isolation layer on the rough surface to isolate the copper foil from the substrate. When the heat-resistant layer treated copper foil is combined with the resin insulated substrate, it can prevent the diffusion of copper ions to the resin layer and prevent the copper foil from reacting with the resin in the subsequent glue curing process, resulting in color spots and peeling problems.
(3) Anti oxidation treatment: copper foil is easy to be oxidized and discolored in the air. The main function of the antirust coating is to prevent copper foil from being oxidized and discolored during storage, transportation and pressing. At present, ZnNi and NiCr alloy layers are used for electroplating, and then a layer of organic silane is dipped.
