聚四氟乙烯(PTFE)非平面延伸微孔膜製備及其特性之研究

Study on micro-porous PTFE membrane preparation and its characteristics by non-plane stretching operation

王梓任(Tzu-Jen Wang)

中原大學/工學院/機械工程研究所/碩士(2012年)

https://doi.org/10.6840/cycu201200881

摘要

聚四氟乙烯（PTFE）是一種十分特殊之材料，由於其獨特的化學結構，使其具有良好的耐候性與抗化性，並廣泛應用於過濾與民生等用途。然而PTFE微孔薄膜製備過程繁複，且相關技術掌握在少數公司，導致其製備技術門檻高，因此突破製程限制的技術為目前發展所需要。
薄膜過濾能力與其面積具有高相關性，傳統大尺寸薄膜為縱向延伸後再經平面橫向延伸方式製成，但此方式易造成膜厚不均以及孔徑尺寸差異。於是本研究建立一新式延伸方式，藉由在薄膜延伸時加入一模具設計(頂起式、滑動式)，進行非平面薄膜橫向延伸，比較不同延伸型式對膜厚、孔徑尺寸、孔隙度之影響，並探討非平面薄膜滑動延伸在不同延伸速度(250、500、10m/min)以及不同延伸溫度(160、180、200 oC)下之薄膜特性。
研究結果發現以非平面薄膜滑動延伸之方式能獲得均勻的膜厚與平均孔徑尺寸；在固定的延伸溫度下，隨著延伸速度的提高，平均孔徑尺寸有越小之趨勢，延伸速度10m/min時，其平均孔徑尺寸約為0.5~0.55μm ，分布率約21.8%；在固定的延伸速度下，隨著延伸溫度提高，平均孔徑尺寸越趨增大，延伸溫度200oC時，其平均孔徑尺寸約0.7~0.8μm ，分布率約45.1%。孔隙度均可達50%。而在延伸後段加入一熱處理，可有效改善薄膜後收縮之問題(減少至約5%)，維持薄膜特性之穩定性。

關鍵字

PTFE微孔薄膜 ； 非平面薄膜橫向延伸

並列摘要

Polytetrafluoroethylene (PTFE) is one of very special materials, due to its characteristic chemical structure, making itself strong resistance to chemical corrosion and high melting temperature therefore has been applied to filtration and civil use. Since the fabrication process of PTFE micro-porous membrane is complicated yet exclusively controlled in a few companies, it is necessary to overcome the limits and the technical difficulties in the process.
The filtration capability of membrane is highly relevant to its surface area. Traditionally, large pore-size membrane is made by plan transverse stretching after longitudinal stretching, thus would easily have non-uniformity in thickness and pore size. Therefore, this study focused on a new novel stretching method by inserting a mold design (upward and sliding) during stretching , and compared the influence on thickness, pore size and porosity by various stretching types, discussed the characteristics of membrane made by non-plane transverse stretching at different ratios (2.5,5,10 m/min) and temperature (160,180, 200 oC).
The results showed that the non-plane transverse stretching can obtain a uniform thickness and the mean pore size of the membrane. Mean pore size at fixed temperature tended to decrease as stretching rate increased. It reduced to 0.5~0.55 μm when stretching rate was 10 m/min with 21.8% distribution. Mean pore size at fixed stretching rate had the trend to increase as the temperature increased. It reached 0.7~0.8 μm when the temperature was 200 oC with 45.1% distribution. Overall 50% porosity can be achieved. After stretching, add a heat treatment process brought a large improvement on shrinkage. Therefore, it can maintain the quality of the membrane stability.

並列關鍵字

non-plane transverse stretching ； PTFE micro-porous membrane

參考文獻

4. S. Ebnesajjad, Fluoroplastics, “Non-Melt Processible Fluoroplastics”, Plastics Design Library, William Andrew Corp, Vol. 1, NY, 2000.

6. Gore. Robert W. “Process for producing porous products”, US Patent, 3953566,1992-11-09.

9. Jizhi Huang, Jianchun Zhang, Xinmin Hao, Yuhai Guo, ”Study of a new novel process for preparing and co-stretching PTFE membrane and its properties”, European Polymer Journal, 40, 667–671, 2004.

11. T. Kitamura, K.I. Kurumada, M. Tanigaki, M. Ohshima and S.I. Kanazawa, “Formation mechanism of porous structure in polytetrafluoroethylene (PTFE) porous membrane through mechanical operations”, Polymer Engineer and Science, 39, 2256–2263, 1999.

12. T. Kitamura, S. Okabe, M. Tanigaki, K.I. Kurumada, M. Ohshima and S.I. Kanazawa, “Morphology change in polytetrafluoroethylene (PTFE) porous membrane caused by heat treatment”, Polymer Engineer and Science, 40, 809–817, 2000.