Preparation of Liquid Crystalline Polymer Films by Coextrusion Film Blowing and Discussion on the Effect of Orientation on Properties of Films

• Main Authors: YU,CHIH-CHUN, 游智鈞
• Other Authors: HUANG,CHUNG-CHING
• Format: Others
• Language: zh-TW
• Published: 2017
• Online Access: http://ndltd.ncl.edu.tw/handle/81718620375053329892

碩士 === 國立高雄應用科技大學 === 模具工程系 === 105 === In recent years, portable mobile is popular, including smart phones, tablet PCs, it’s a big market value in world. With the development of high-tech electronic products, the quality of parts in mobile is more and more important ,the main film material of flexible printed board in mobile is PI(Polyimide) until now, but the Water absorption and Dielectric properties of PI is poor in high frequency. the other material”Liquid Crystal Polymer” ,it’s Water absorption and Dielectric properties is better than PI,but it’s price is also higher than PI. Cause the molecular structure of LCP is ramdomly and have rigid rod molecular, make LCP have extremely low melt viscosity,this characteristic make LCP difficult to process in film laminating and blowning. Since the molecule of LCP is rigid, the rigid-rod molecules are easily aligned in the same direction of the shear stress, and be strongly oriented in one direction(Anisotropic), Anisotropic make LCP flim strength have a big difference between transverse(TD) and machine direction(MD),therefore, making biaxially-oriented LCP film and stably has became trend. This study use Extrusion to make LCP film, because the Anisotropic, this study use film blowing which processing have transverse direction extension, LCP have extremely low melt viscosity, it’s hard to blowing nd become film, therefore, this study use Three-layer co-extrusion blown film machine, use A/B/A method, let HDPE be inside and outside layer、LCP be middle layer, HDPE has high melt viscosity can carry LCP and support LCP become film, he HDPE layer can reduce the cooling speed of LCP layer, make the processing easy, by the way, LCP and HDPE is incompatible, so the 3 layer film can separate easily, than get the LCP film. This study use Inflate(blowing)、Thermoforming, make the LCP film Biaxially, the result shows Inflate is not very effective,； Thermoforming transform the orient angle,the bigger of the angle,the MD tensile strength smaller, the TD tensile strength bigger,if the orient angle become 90∘,MD and TD tensile strength close to the same。