Development of Adhesive-Free Lamination of Liquid Crystal Polymer Using a Plasma Surface Treatment at Atmospheric Pressure

A liquid crystal polymer (LCP) film were adhered by plasma treatment at atmospheric pressure and thermocompression without using an adhesive. The adhesive strength of plasma treated film increased drastically and plasma treated film indicated cohesive failure inside the film. In addition, the treatment time required to cause cohesive failure was shortened by increasing the discharge power and shortening the distance between the plasma outlet and the sample surface. According to the valence band XPS spectra, it is assumed that the melting point of film surface decreased. The adhesive strength of Ar/He plasma treated film increased and the treatment time required to cause cohesive failure was shortened by containing Ar.