Liquid crystal polymer film as well as preparation method and application thereof

Abstract

The invention provides a liquid crystal polymer film as well as a preparation method and application thereof, and relates to the technical field of functional films. The liquid crystal polymer film has an ABA three-layer structure, and the upper surface and the lower surface of a middle layer B are respectively covered with a layer A; the middle layer B is mainly composed of a liquid crystal high-molecular polymer; and the layer A is mainly composed of a liquid crystal high-molecular polymer, polyetherimide and a compatibilizer. According to the liquid crystal polymer film prepared from the raw materials and the structure, the polyetherimide and the compatibilizer are added into the layer A, so that the interface bonding strength of the liquid crystal polymer film and a copper foil can be remarkably improved, and meanwhile, the prepared composite film keeps excellent mechanical property, heat resistance and high-frequency dielectric property. In addition, the liquid crystal high-molecular polymer in the middle layer B of the liquid crystal high-molecular film is the same as the liquid crystal high-molecular polymer in the layer A, so that the compatibility of the liquid crystal high-molecular polymer between the layer A and the layer B is effectively ensured.

Description

technical field [0001] The invention relates to the technical field of functional thin films, in particular to a liquid crystal polymer thin film and its preparation method and application. Background technique [0002] As a new type of high-frequency and high-speed transmission medium material, liquid crystal polymer film is gradually being more and more widely used in 5G terminals. Liquid crystal polymers have the following excellent performance characteristics: (1), low dielectric constant (≤3.3) and good stability, and can maintain a constant dielectric constant in the frequency range of 0-110GHz; (2), high-frequency dielectric constant The electrical loss is small, and can be kept less than 0.005 in the range of 110 GHz; (3), low water absorption (~0.04%); (4), excellent dimensional stability. These characteristics make the liquid crystal polymer film an ideal high-frequency flexible copper clad laminate substrate. [0003] In high-frequency flexible circuit boards, a...

AI Technical Summary

Problems solved by technology

However, the surface roughness of the conductive layer has a significant impact on the bonding strength of the two

If the traditional surface treatment technology is used to roughen the surface of the conductive copper foil, although the bonding strength between the liquid crystal polymer substrate and the copper foil can be effectively improved, the rough interface will increase the transmission distance of high-frequency signals, resulting in severe signal loss, or even failure, so copper foil with low surface roughness must be used

However, the use of copper foil with low surface roughness (0.1-3.5μm) will cause the problem of weak bonding between copper foil and liquid crystal polymer substrate

Images