The Establishment and Mechanism Study of Pressure Sensitive Adhesive Testing System
|Keywords:||探棒式測試法;非圓形幾何探棒;孔穴;人工缺陷點;Probe Tack Testing;non-circular probe;cavity;artificial defect||Issue Date:||2011||Abstract:||
本研究建立起一套重複性良好的探棒式測試方法，用來探討感壓膠的黏性測試。此測試方法作動機制簡單，有別於剝離測試法(peel testing method)，探棒式測試法排除了膠體背板(adhesive carrier)的影響，可直接量測到感壓膠本身的特性。有別於一般使用金屬材質的探棒，本研究使用矽晶圓製作探棒，可將表面粗糙度所造成的影響減至最小，並有相當好的表面平整度，減少接觸膠面時的不平整現象。為測試本系統可用性，在實驗中探討了影響實驗的參數：膠體厚度、剝離速度、接觸時間等，這些實驗結果與文獻比較皆有相同的趨勢發展。
使用探棒式測試感壓膠時，在剝離的過程中會有孔穴(cavity)的出現，這些孔穴是隨機的出現，無法定量的控制其產生的位子及個數。在本研究中首先使用PMMA顆粒作為人工缺陷點，進而成功地誘導出單一孔穴，觀察其發展情況；另外也發現人工缺陷點在不同的探棒接觸位置，所得到的最大應力值σ1p也會有所不同，此乃探棒接觸膠面產生的應力分佈場所致，影響應力分佈場的參數為探棒半徑與膠體厚度的比值α (= a/h0)。實驗中使用不同探棒半徑與不同膠體厚度，進行人工缺陷點誘導孔穴實驗時，實驗結果發現相同α值條件下所得之無因次化最大應力
A probe tack testing system was built in this study. Unlike peel testing, the probe tack testing eliminates the effect of adhesive carrier. It can measure the characteristics of PSA purely. In this study, the probes were made by silicon wafer instead of stainless steel with the benefits of good surface roughness and flatness. The experimental parameters such as thickness of adhesive, debonding velocity and dwell time are discussed in the research to test the reliability of this system.
Besides, in order to study the growth of cavity, a method of generating single cavity was first proposed. A PMMA particle was introduced as an artificial defect to induce the formation of the single cavity. Furthermore, it was observed that the peak stress σ1p was correlated with the location of particle on adhesive surface. The experiments with different probe diameters (a) and adhesive thickness (h0) were tested. Under the same α, the normalized peak stress was the same for different probe diameter and adhesive thickness. The results show that the dimensionless term α (= a/h0) dominated the debonding mechanism.
Moreover, the effects of probe geometry were discussed. The circular, annular and rectangular probes made of silicon wafer were used. Some had same contact area, the others had same contact perimeter. The results showed that peak stress was affected not only contact area but contact perimeter. Also, the parameter hydraulic diameter Dh was used for annular and rectangular probes to make a good correlation with peak stress
|Appears in Collections:||應用力學研究所|
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