Iseki Masashi, Suzuki Yasuhito, Tachi Hideki, Matsumoto Akikazu
Department of Applied Chemistry, Graduate School of Engineering, Osaka Prefecture University, 1-1 Gakuen-cho, Naka-ku, Sakai, Osaka 599-8531, Japan.
Research Division of Polymer Functional Materials, Izumi Center, Osaka Research Institute of Industrial Science and Technology, 2-7-1 Ayumino, Izumi, Osaka 594-1157, Japan.
ACS Omega. 2018 Nov 30;3(11):16357-16368. doi: 10.1021/acsomega.8b02371.
A dismantlable adhesion system satisfies both a strong bonding strength during use and a quick debonding process on demand in response to an external stimulus as a trigger for dismantling. In this study, we synthesized acrylate copolymers consisting of 2-(-butoxycarbonyloxy)ethyl acrylate (BHEA), 2-ethylhexyl acrylate (2EHA), and 2-hydroxyethyl acrylate (HEA) as the repeating units and evaluated the properties as dismantlable adhesives. First, the thermal degradation behavior of the obtained polymers was investigated by thermogravimetric analysis and IR spectroscopy. The BHEA-containing polymers were thermally stable during heating at a temperature below 150 °C, but they rapidly degraded, i.e., the deprotection of the -butoxycarbonyl groups occurred during heating at 200 °C. The onset temperatures for the deprotection depended on the BHEA and HEA contents and their sequence structures because the hydroxy group in the side chain accelerated the deprotection via an autocatalytic reaction mechanism. Shear holding power and 180° peel tests were carried out with the pressure-sensitive adhesive tapes using the BHEA-containing copolymers as the adhesive materials. The copolymers consisting of the BHEA, 2EHA, and HEA units with 25.7, 35.0, and 39.3 mol %, respectively, exhibited the highest adhesion strength and the subsequent quick reduction of the adhesion strength by heating during the dismantling process. The addition of hexamethylene diisocyanate as the cross-linker and Zn(acac) as the Lewis acid to the adhesive polymers was demonstrated to be valid for the design of high-performance dismantlable adhesion systems. A change in the rheological properties during the dismantling process was important for a quick response and selective interfacial failure between the substrate and the adhesive.
一种可拆解的粘附系统既满足使用过程中的强粘结强度，又能在外部刺激作为拆解触发因素的情况下，根据需求快速进行脱粘过程。在本研究中，我们合成了以2-（-丁氧基羰基氧基）乙基丙烯酸酯（BHEA）、丙烯酸2-乙基己酯（2EHA）和丙烯酸2-羟乙酯（HEA）为重复单元的丙烯酸酯共聚物，并评估了其作为可拆解粘合剂的性能。首先，通过热重分析和红外光谱研究了所得聚合物的热降解行为。含BHEA的聚合物在低于150℃的温度下加热时热稳定，但在200℃加热时迅速降解，即丁氧基羰基基团在加热过程中发生脱保护。脱保护的起始温度取决于BHEA和HEA的含量及其序列结构，因为侧链中的羟基通过自催化反应机制加速了脱保护。使用含BHEA的共聚物作为粘合剂材料，对压敏胶带进行了剪切保持力和180°剥离试验。分别由摩尔分数为25.7%、35.0%和39.3%的BHEA、2EHA和HEA单元组成的共聚物表现出最高的粘附强度，并且在拆解过程中通过加热随后粘附强度迅速降低。向粘合剂聚合物中添加六亚甲基二异氰酸酯作为交联剂和Zn（acac）作为路易斯酸被证明对高性能可拆解粘附系统的设计是有效的。拆解过程中流变性能的变化对于快速响应以及基材与粘合剂之间的选择性界面破坏很重要。
