Two-layer adhesive-free double-sided flexible copper-clad plate and preparation method thereof

Abstract

The invention relates to a two-layer adhesive-free double-sided flexible copper-clad plate and a preparation method thereof, wherein the copper-clad plate comprises an upper copper foil layer, a lowercopper foil layer and an insulating layer sandwiched between the two copper foil layers. The insulating layer comprises a polytetrafluoroethylene thin film at the middle and PBS / PLA composite thin films located on the upper side and the lower side of the polytetrafluoroethylene thin film. Used PBS and PLA not only have good ductility and elongation at break, but also have good heat resistance andimpact resistance; molecule chains do not contain flexible groups, have small free volume and do not easily absorb water; moreover, the PBS and PLA themselves are thermoplastic materials and are molten and pressed at high temperature, the bonding between the insulating layer and the copper foils can also be realized, and after the PBS and PLA replace thermoplastic polytetrafluoroethylene resin (TPI), the problems of poor heat resistance and easy water absorption of TPI are perfectly solved. Therefore, the adhesive-free double-sided flexible copper-clad plate provided by the invention has highpeeling strength and dimensional stability.

Description

technical field [0001] The invention relates to a copper clad laminate and a preparation method thereof, in particular to an adhesive-free double-sided flexible copper clad laminate and a preparation method thereof, belonging to the technical field of copper clad laminates. Background technique [0002] In recent years, with the high performance, miniaturization and light weight of digital cameras, digital video cameras, car navigators, computer accessories and other electronic products, as well as the emergence of high-end electronic products, such as tablet computers and smart phones, the electronic Lines are also constantly developing towards the trend of "light, thin, short, and small". Traditionally used rigid copper clad laminates do not have flexibility, and the electronic circuits obtained cannot be bent and assembled, and are bulky, which can no longer meet actual needs. Double-sided flexible CCL with high density, multi-layer, high heat resistance, and high dimens...

AI Technical Summary

Problems solved by technology

[0003] The traditional manufacturing method of double-sided flexible copper-clad laminates is a three-layer adhesive type, and its thickness is generally 24.5 to 110 μm, which cannot meet the requirements of thinner and flexible copper-clad laminates, and the production uses low heat resistance. Adhesives cannot meet the heat resistance, soldering stability and other properties, and it is easy to delaminate and foam when used at high temperature. Therefore, it is widely considered not to use epoxy resin or acrylic adhesives, but to use only polytetrafluoroethylene materials as insulating layers. Two-layer adhesive-free double-sided flexible copper clad laminate

[0004] Known polytetrafluoroethylene materials are divided into non-thermoplastic polytetrafluoroethylene resin (PI) and thermoplastic polytetrafluoroethylene resin (TPI). There are obvious differences in performance. The thermal expansion coefficient of non-thermoplastic polytetrafluoroethylene resin (PI) is relatively low. It is used in copper clad laminates to make copper clad laminates have good dimensional stability and high heat resistance, but its peeling off from copper foil The strength is relatively low and it is difficult to use it alone; the heat resistance of thermoplastic polytetrafluoroethylene resin (TPI) is not as good as that of non-thermoplastic polytetrafluoroethylene resin, but the coefficient of thermal expansion is high, and the dimensional stability of the supported copper clad laminate shrinks too much, but it can It is melted and pressed at high temperature to realize the thermocompression bonding between the resin layer and the copper foil. Therefore, there are both thermoplastic polytetrafluoroethylene and non-thermoplastic polytetrafluoroethylene in the current two-layer double-sided flexible copper clad laminate. One in which the non-thermoplastic PTFE resin provides excellent dimensional stability and the non-thermoplastic PTFE resin acts as a bond to achieve both good dimensional stability and high peel strength

[0005] At present, there are two mainstream structures of commercial two-layer double-sided flexible copper clad laminates, Cu / TPI / PI / TPI / Cu and Cu / PI / TPI / PI / Cu. Copper-clad laminates have both high peel strength and good dimensional stability, but the problem is that the TPI on the outer layer has poor heat resistance. When it encounters combustion, the TPI layer is easy to decompose, resulting in the two-layer method. The flame retardancy of flexible copper clad laminates is poor. At the same time, because TPI itself contains more flexible groups and has a larger free volume, it is easy to absorb water, and it is easy to cause Explosive plate, although the latter structure avoids the impact of TPI deficiency to a certain extent, it is difficult to completely avoid the problems caused by TPI performance deficiency, and this structure has a great impact on the formulation and production process of TPI and PI. The requirements are high, which increases the difficulty of production

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