Polytetrafluoroethylene flexible copper-clad plate containing glass fabric and preparation method thereof

Abstract

The invention discloses a polytetrafluoroethylene flexible copper-clad plate containing glass fabric and a preparation method of the polytetrafluoroethylene flexible copper-clad plate. The structure of the polytetrafluoroethylene flexible copper-clad plate containing the glass fabric sequentially comprises an upper copper foil layer, an upper fusible polytetrafluoroethylene layer, an upper mixed layer, a glass fabric layer, a lower mixed layer, a lower fusible polytetrafluoroethylene layer and a lower copper foil layer from top to bottom, wherein the upper mixing layer and the lower mixing layer are prepared by blending polytetrafluoroethylene and fusible polytetrafluoroethylene; and the glass fabric has a grid structure. The mechanical property of the prepared polytetrafluoroethylene flexible copper-clad plate containing the glass fabric is effectively improved, the stability is relatively good, meanwhile, relatively high electrical property is also ensured, and the application prospect is good.

Description

technical field [0001] The invention relates to the technical field of manufacturing of fluorine-based flexible copper clad laminates, in particular to a polytetrafluoroethylene flexible copper clad laminate containing glass fiber cloth and a preparation method thereof. Background technique [0002] Flexible Copper Clad Laminate (FCCL) is a basic material in the electronics industry and an indispensable substrate material for the preparation of flexible printed circuit boards (FPCB). Under the overall situation of accelerating the development of electronic components and 5G industry in today's world, high-frequency and high-speed FCCL should have ultra-low loss, low transmission signal dispersion, and high characteristic impedance precision flexible copper clad laminate material. Therefore, the core requirements of high-frequency and high-speed FCCL are low dielectric constant (Dk) and low dielectric loss (Df). At the same time, in order to meet the processing characteristic...

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Problems solved by technology

However, due to its large fluorine atom radius and negative charge, it has a shielding effect on the positive charge of the carbon atoms in the main chain, resulting in PTFE's extremely low cohesive energy and weak intermolecular bonding.

[0004] At present, the mainstream direction of preparing PTFE flexible copper clad laminates is to combine PTFE with a modified polyimide (MPI) film with high tensile strength to make a composite material dielectric layer, and then press copper foil at high temperature to prepare PTFE flexible clad laminates. Copper plate, although MPI has good mechanical properties and dimensional stability, which makes up for the defects of poor mechanical properties and large thermal expansion coefficient of PTFE, but MPI has a high water absorption rate, resulting in the Dk and Df values ​​​​of the composite dielectric layer under normal conditions due to the water absorption of MPI However, if it becomes larger, the excellent dielectric properties of PTFE will be greatly reduced, and the excellent dielectric properties of PTFE flexible copper clad laminates will not be fully utilized.

[0005] There are also studies on the method of impregnating PTFE emulsion with glass fiber cloth to form a prepreg, and then pressing copper foil to prepare a copper-clad laminate. However, there are some problems in this copper-clad laminate preparation method. Wettability is poor, and there are situations where multiple dipping is required, which is not conducive to mass production; there is uneven distribution of PTFE in the process of impregnating PTFE emulsion, and the problem of poor uniformity of the prepared product is not conducive to downstream PCB circuit processing

In addition, since the PTFE emulsion prepreg impregnated with glass fiber cloth has not undergone the sintering process, the processing time of the later prepreg pressing copper foil process is too long. At the same time, PTFE has the defect of large thermal expansion coefficient, which makes the prepreg pressing process that has not been sintered in the pressing stage Too harsh, greatly reducing product yield and production efficiency

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