AbstractPressure‐sensitive adhesives (PSAs) are made from soft, irreversibly lightly crosslinked polymers. Even after removal from surfaces, they retain insoluble networks which pose problems during the recycling of glass and cardboard. Herein, degradable PSAs are presented that provide the required performance in use but have networks that can be degraded after use. A series of copolymers was prepared through radical copolymerization of n‐butyl acrylate, 4‐acryloyloxy benzophenone (ABP) photo‐crosslinker, and dibenzo[c,e]oxepin‐5(7H)‐thione (DOT) to provide degradable backbone thioesters. The optimum tack and peel strengths were found for molar contents of 0.05 mol% ABP and 0.25 mol% DOT. Degradation of the backbone thioesters through aminolysis or thiolysis led to the full dissolution of the networks, loss of adhesive properties of films (decreases in the measured tack and peel strengths), and the quick detachment of model labels from a substrate. Inclusion of DOT into PSAs offers a viable route toward degradable and recyclable packaging labels.
摘要压敏胶(PSA)是由柔软的、不可逆的轻度交联聚合物制成的。即使从表面移除后,它们仍保留着不溶解的网络,这给玻璃和纸板的回收利用带来了问题。本文介绍的可降解聚苯乙烯表面活性剂可在使用中提供所需的性能,但其网络可在使用后降解。通过丙烯酸正丁酯、4-丙烯酰氧基二苯甲酮(ABP)光交联剂和二苯并[c,e]氧杂卓-5(7H)-硫酮(DOT)的自由基共聚,制备了一系列共聚物,从而提供了可降解的骨架硫代酯。发现摩尔含量为 0.05 摩尔%的 ABP 和 0.25 摩尔%的 DOT 具有最佳的粘性和剥离强度。骨架硫代酯通过氨基分解或硫代分解发生降解会导致网络完全溶解、薄膜失去粘合性能(测量的粘着强度和剥离强度降低)以及模型标签从基底上快速脱落。在 PSAs 中加入 DOT 为实现可降解和可回收包装标签提供了一条可行的途径。