石墨烯複合材料加熱滾筒應用於連續環帶輪式滾壓成型製程之開發

Abstract

高分子微熱壓成型製程，可以連續快速生產，在微結構複製上廣被運用，但如何使加溫時間更縮短、溫度分布更平均、壓印壓力更均勻，是滾壓成型一直面臨的挑戰。故本研究利用具備優異電熱性質及機械性質之石墨烯複合材料，塗佈於中空滾輪內壁，開發石墨烯複合材料加熱滾輪，並導入環帶輪對輪製程技術、矽膠軟墊均壓概念於機台設計，結合其優點，達到快速升溫、升溫溫度均勻性佳、施壓均勻以及連續製程之目的。 本研究首先測試平板式塗佈之石墨烯複合材料的機械強度，透過自行設計之撓曲測試機台，對石墨烯複合材料加熱器平板進行撓曲測試，並量測其於撓曲時之電阻值變化，實驗結果在撓曲時之電阻值變化量低於2 %。另外對石墨烯複合材料加熱器表面施壓，並觀察其升溫溫度分布在施壓前後之變化，實驗結果其升溫溫度分布不因受壓而改變。最後探討其電熱性質及升溫均勻性，其可於施以35 V時，達到130 °C，並且持溫超過600 s以上，證明其升溫穩定性；在溫度均勻性方面，其升溫至120 °C時，其滾筒整面積最大溫差2 °C內，可看出其優異的升溫溫度均勻性。實驗結果驗證此石墨烯複合材料加熱器具優異之抗撓曲、抗壓以及優異加熱功能。 本研究將石墨烯複合材料塗佈於中空圓筒內側，製作具加熱功能的滾輪，並結合矽膠軟墊以及環帶輪式滾壓機構，製作連續環帶輪式熱滾壓機台。透過滾壓將V型微結構複製於PMMA基材上，在160 °C時，其複製轉寫率最高可達98 %，證實此連續環帶輪式微熱滾壓機台能成功複製微結構。本研究證實石墨烯複合材料加熱滾輪可用於連續環帶輪式滾壓成型的連續生產。

Roller hot embossing is an effective continuous mass production for replicating microstructures. To increase quality and efficiency of the process, how to shorten the heating time, improve the uniformity of the temperature and pressure distribution are constant challenges. This study is devoted to developing a heating roller by coating the graphene polymeric composite on the inner wall of a hollow roller. In this study, heating roller is combined with steel track and silicone cushion to form a continuous production facility with simple mechanism, high temperature uniformity and high pressure uniformity. The mechanical properties of graphene polymeric composite heater plates were first investigated. A flexure tester was designed, and the electric resistance of graphene polymeric composite heater was measured during the bending test. The experimental results show that the electrical resistance deviation during bending test is less than 2 %. By comparing the temperature distribution of the heater before and after applying the pressure upon it, the robustness was confirmed. The temperature distribution of the heater was s before and after the test. Then, the electrothermal properties and temperature uniformity of the graphene polymeric heater roller were measured. The roller heater can reach 130 °C with a voltage of 35 V, and the temperature can remains more than 600 s, implying temperature stability. In terms of temperature uniformity, at 120 °C, the maximum temperature difference of the roller heater is 2 °C. The experimental results proves that the graphene polymeric composite heater has excellent mechanical and electrothermal properties. A roller hot embossing facility was designed and implemented, integrating the graphene composite heater roller, steel track and silicone cushion. The replication of V-shaped microstructures on PMMA 150 x 110 mm2 substrate was performed. The replication rate is more than 98 % at 160 ° C. In this study, we prove the capability and feasibility of using graphene polymeric roller heater in steel track roll-to-roll hot embossing facility. The potential of graphene composite heater rolling embossing for mass production has been demonstrated.