水性壓克力感壓膠添加不同增稠劑之流變探討

Rheology effect of various thickeners on the adhesion property of water-based acrylic PSA

鄭妃婷(Fei-Ting Cheng)

指導教授 ： 芮祥鵬

國立臺北科技大學/工程學院/有機高分子研究所/碩士(2013年)

摘要

本研究分別利用陰離子型乳化劑、非離子型乳化劑於78℃下，以起始劑過硫酸鉀 (KPS)進行丙烯酸-2-乙基己酯 (2-EHA)、甲基丙烯酸甲酯 (MMA)、醋酸乙烯酯 (VAc)、丙烯酸 (AA)、 甲基丙烯酸 (MAA)之乳化聚合反應製備水性感壓膠。反應透過配方中的丙烯酸 (AA) 及甲基丙烯酸 (MAA) 來控制羧酸含量。探討羧酸含量對粒徑、黏度、初期黏著力、黏著力、內聚力及動態黏彈性質之影響。
為了調整的水性感壓膠的流變性質，分別加入不同量的鹼溶脹型丙烯酸增稠劑 (HASE)和疏水改性乙氧基化的聚氨基甲酸酯增稠劑 (HEUR)。增稠後的黏膠水溶液，定性分析其流變性質、黏度及pH值變化之影響。
乳化聚合反應後的水性感壓膠，我們發現隨羧酸含量增加，粒徑逐漸降低，黏度則些微升高。由於AA與MAA的增加，經由動態機械分析儀 (DMA)的分析，我們發現感壓膠的Tg逐步上升，內聚力亦升高，導致初期力和黏著力遞減，保持力提升。
HASE增稠劑的添加，由於增稠劑與感壓膠的相互作用，會使水性感壓膠的黏度增加，呈現剪切稀化行為。從實驗中觀察到，黏膠的羧酸含量增加，HASE增稠效果受到影響，黏度上升幅度明顯變小。同時也發現到，黏膠pH值的改變，對於HASE增稠後的黏度產生劇烈影響，顯著地降低。相對地，HEUR增稠劑的添加，同樣會使水性感壓膠的黏度增加，但隨黏膠中羧酸含量的增加，流變性質會從接近牛頓行為逐漸趨向於剪切稀化行為。而黏膠pH值的降低，對於HEUR增稠溶液的影響不大。

關鍵字

乳化聚合 ； 感壓膠 ； 增稠劑 ； 流變 ； 剪切稀化 ； 牛頓流體

並列摘要

Acrylic copolymer latexes were prepared by emulsion polymerization process using anionic surfactant and nonionic surfactant as the emulsifier, respectively, and potassium persulfate (KPS) as the initiator at 78℃. The co-monomers used were 2-ethylhexyl acrylate (2-EHA), methyl methacrylate (MMA), vinyl acetate (VAc), acrylic acid (AA) and methacrylic acid (MAA). The latex was converted to pressure-sensitive adhesive (PSAs) then. Acrylic acid (AA) and methacrylic acid (MAA) to control the carboxylic acid content in the formula. Explore the carboxylic acid content on the particle size, viscosity, initial adhesion, adhesion, cohesion and the impact of the dynamic viscoelastic properties.
To adjust the rheology of waterborne pressure-sensitive adhesives, different amounts of a alkali swellable acrylic emulsions (HASE) and hydrophobically modified ethoxylated polyurethane thickener (HEUR) were added. The thickened adhesive solutions were characterized by flow rheology, viscosity and the effect of changes in pH.
After polymerization of the waterborne pressure-sensitive adhesives, we found that along with the increase of carboxylic acid content, the particle size decreases, the viscosity is slightly increased. By dynamic mechanical analyzer (DMA) analysis, we found that AA and MAA increases, the Tg of the Pressure Sensitive Adhesive gradually increased, cohesion has also increased, leading to the initial adhesion and peel strength decreasing.
For HASE thickener, the viscosity of the waterborne pressure-sensitive adhesives increased, showing shear thinning behavior, which can be ascribed to the existence of interactions between the water-based pressure-sensitive adhesives and the thickener. From the experiments it was observed that the adhesive of carboxylic acid content increased, HASE thickening effect is affected, the viscosity rise significantly slower. Also found that the pH value of the adhesive change, HASE thickened viscosity have a dramatic impact, significantly reduced. Furthermore, water-based adhesives add HEUR thickeners to increase the viscosity. However, the carboxylic acid content of the adhesive increases, the rheological properties from Newtonian behavior gradually became the shear thinning behavior. The decrease in pH of viscose, the solution of the HEUR thickener is not.

並列關鍵字

Emulsion Polymerization ； Pressure Sensitive Adhesive ； Thickener ； Rheology ； Shear Thinning ； Non Newtonian Flow

參考文獻

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