In recent years, the varieties of copper processing materials in China have undergone tremendous changes. In the close integration of market and scientific and technological development needs, the development of new products and new materials has achieved remarkable results. Traditional copper processing materials have gradually completed the transition to modern copper processing materials. Its important feature is the development of high precision, high performance, environmental protection, and energy saving. Many products have become well-known brands at home and abroad, enjoying a high reputation in the domestic and foreign markets; product quality has been steadily improved, and the level of product standards has been in the international advanced ranks. In addition to producing according to national standards, major copper material manufacturers can also directly accept orders from major developed countries in the world. This shows that China's copper processing material production is further internationalized; in order to meet the various needs of the national economy and technology for copper materials, Various copper processing companies have also formulated many internal supply technical standards accordingly. The main copper varieties are as follows:
(1) Rolled copper foil
Rolled copper foil is an important material for making flexible printed circuit boards (FPC). With the promotion and popularization of high-end, miniaturized and portable electronic products such as mobile phones, notebook computers, digital cameras, camcorders, and LCD displays, the demand for flexible printed circuit boards has soared. In addition to static bending, flexible printed circuit boards can also be dynamically bent and folded to achieve three-dimensional development, which can effectively improve the freedom and flexibility of circuit design and mechanical design, and improve the reliability and stability of the entire system of electronic equipment. The copper foil used in flexible printed circuit boards includes both rolled copper foil and electrolytic copper foil. Because of its high ductility and excellent mechanical properties, rolled copper foil is more and more used, especially in many special occasions. At present, about 70% of FPC in industrially developed countries use rolled copper foil, while the remaining 30% use electrolytic copper foil. China's enterprises using rolled copper foil to manufacture FPC are starting, and the materials mainly rely on imports. This time, Chinalco Shanghai Copper's new 80,000 tons project, the product plan has an annual output of 3,000 tons of rolled copper foil of 0.007～0.035*650mm .
In addition, Shandong Heze and Guangyuan Copper Strip Co., Ltd. plan to produce 60,000 tons of high-precision copper strip projects with an annual output of 5,000 to 8,000 tons of rolled copper foil, and plan to implement its copper foil part first.
(2) Lead frame copper tape
Lead frame copper tape is a key material for integrated circuits. At present, packaging in the form of lead frames accounts for more than 80% of all IC packages and is used to manufacture lead frames for integrated circuits and discrete devices. An average of 100 million pieces requires 100 tons of copper strip. In 2005, the domestic output of integrated circuits reached 26.5 billion pieces. In the past few years, it has increased by about 20% every year. In the second half of last year, due to the impact of the financial turmoil, the output dropped significantly. In 2006, the industrialization level of my country's lead frame copper strip has been greatly improved, and Luotong Group and Ningbo Xingye have become their important production bases. At present, the domestic self-sufficiency rate of copper strip for discrete devices has increased, while the lead frame copper strip for high integration still relies on imports. The C194 alloy with medium strength and medium conductivity has been industrialized in China, and the research and development of the C7025 alloy with high strength and high conductivity has begun. The higher strength copper-chromium-zirconium alloy is still blank. This time, Chinalco Luo Copper and Chinalco Daye's projects focus on lead frames and cable copper tapes.
(3) Transformer copper strip
It is mainly used to make the flex group of dry-type transformers and has been popularized and applied in oil-immersed transformers, which has great market potential. It is resistant to impulse voltage, has strong short-circuit and overload resistance, high efficiency, flame retardant, explosion-proof, low noise, small size, light weight, maintenance-free, low operating cost, high use safety and environmental protection adaptability. Dry-type transformers developed rapidly all over the world in the middle and late last century, and entered our country in the late 1980s. At present, our country has become one of the largest countries in the world in the production and sales of dry transformation. The output in 2005 has exceeded 50 million kVA. Under normal circumstances, the low-voltage side dry transformer uses 400KG copper tape for every 1000KVA capacity. If the high and low voltage sides are all made of copper tape, 880KG copper tape is used per 1000KVA capacity. At present, all copper strips for high and low voltages account for about 20% of the total output, and the rest are copper strips for low voltages and copper wires for high voltages. In 2006, the use of copper strip for transformers exceeded 60,000 tons. The requirements for this product are greater roll weight, higher precision, better surface quality, higher conductivity, and no burrs on the strip edges.
