- 學位論文
模具式塗佈操作條件對PTFE布膜影響之研究
Studying The Effect Operating Conditions of Die Coating Process on PTFE-coated glass fabric
摘要
PTFE塗佈玻璃纖維布膜(PTFE-coated glass fabric)是由無機材料(玻璃纖維布)和有機材料(PTFE)所組成，本研究分別以狹縫式(Slit die)和押出式(Slot die)兩種型式的模具對玻纖布進行塗佈，塗佈後進入烘箱做乾燥和鍛燒的程序，最後將製成的成品利用掃描式電子顯微鏡(SEM)檢視膜面和依據CNS 12915 L3233以及ASTM D5035做PTFE布膜斷裂強度(Breaking force)的檢測。 從實驗結果中可看出，在相同的塗佈次數下，不管是從塗佈厚度或是塗佈覆蓋率(cover factor)來看，模具式塗佈(Die coating)的成品優於浸沾式塗佈成品(Dip coating)；而根據以往研究顯示斷裂強度除與乾燥條件有關外，在減少鍛燒次數或降低鍛燒溫度下，可有效的提升斷裂強度，因此兩種模具中又以可以進行快速塗佈，縮短操作時間的押出式塗佈其所製成的成品優於其他塗佈方式之成品。 另外，為了將本研究結果能用於未來的放大設計，將實驗數據無因次化時，發現在慣性力/黏滯力(Reynolds number)對黏滯力/表面張力(Capillary Number)比值小於450時，無因次塗佈寬幅會呈現不穩定而且會造成塗佈不均，此結果可提供塗佈模具寬幅逾60公分以上的布膜使用多點進料操作時的參考。
並列摘要
The PTFE-coated glass fabric was prepared from inorganic materials (glass fiber) and organic materials (PTFE). In this study, the glass fabric was coated with PTFE solution by slit die and slot die respectively, then dried and sintered. The finished PTFE-coated fabric surface was observed by Scanning Electron Microscope (SEM) and its breaking force test was conducted by complying with CNS 12915 L3233 and ASTM 5035-11. Based on coating thickness or coating cover factor, it was found die coating was better than dip coating. The breaking force of coated fabric not only depends on drying conditions but also sintering times and temperature. Reducing sintering time and temperature can significantly increase the breaking force. Because slot die coating can achieve to saturation in shorter time, so the finished fabric has a larger breaking force than that of slit die coating. Finally, experimental data obtained was transformed into dimensionless groups. When the ratio of inertial force/viscous force (Reynolds number) to viscous force/surface tension (Capillary number) is smaller than 450, the dimensionless coating width W^* becomes unstable and non-uniform. This result can apply to multiple inlet of larger than 60cm wide slot die coaters.