ABSTRACT

Adhesive bonding represents a widely established manufacturing process, which offers many advantages such as joining of different materials while resulting in a more advantageous stress distribution when loaded. Compared to other, mainly mechanical, joining techniques, the long curing times of adhesives – sometimes up to days – represent a decisive disadvantage. After adhesive application, contractors have to maintain these times until components can be moved for further processing, or full load can be applied. Different methods are used to circumvent the problem of adhesive cure, and thus accelerate polymerisation, among others, microwave, UV or conventional oven curing. In addition to aforementioned methods, the use of electromagnetic induction represents a promising non-contact method for accelerated curing. With this method, bonded components are exposed to a high frequency (HF) electromagnetic field (EMF), which generates heat that is transmitted to the adhesives to be cured, and in turn speeds up polymerisation. If adherends, like for example wood, glass, or G-FRP, are not sensitive to EMF, so-called susceptors (e.g. meshes, fibres or particles) are introduced into the adhesives, which can be heated inductively. Curie particles (CP) represent a special type of susceptors, which can only be inductively heated up to their material specific Curie temperature (T_c) above which heating automatically stops. Thus, a curing process is designed, which is independent from external temperature monitoring techniques and – at the same time – prevents the adhesives from overheating. The present study investigated the influences of inductive curing with CP on the bulk properties of a 2 K epoxy resin and a 2 K polyurethane using standardised specimen types: adhesive bulk (AB) and dynamic mechanical analysis (DMA) specimens. The authors showed with an experimental programme of 92 specimens that resulting thermo-mechanical bulk properties of the two investigated adhesives are fundamentally changed by application of the process.

摘要

粘合剂粘合代表了一种广泛建立的制造工艺，它提供了许多优点，例如连接不同的材料，同时在加载时产生更有利的应力分布。与其他主要是机械连接技术相比，粘合剂的长固化时间（有时长达数天）是一个决定性的劣势。使用粘合剂后，承包商必须保持这些时间，直到可以移动组件进行进一步处理，或者可以应用满负荷。使用不同的方法来规避粘合剂固化的问题，从而加速聚合，其中包括微波、紫外线或传统烘箱固化。除了上述方法之外，电磁感应的使用代表了一种用于加速固化的有前途的非接触方法。用这种方法，粘合组件暴露在高频 (HF) 电磁场 (EMF) 中，该电磁场产生的热量传递到要固化的粘合剂，进而加速聚合。如果被粘物（例如木材、玻璃或 G-FRP）对 EMF 不敏感，则称为感受器（例如。网、纤维或颗粒）被引入粘合剂中，可以感应加热。居里粒子 (CP) 代表一种特殊类型的感受器，只能感应加热到其材料特定的居里温度₍ Tc) 加热自动停止。因此，设计了一种固化工艺，该工艺独立于外部温度监测技术，同时防止粘合剂过热。本研究使用标准化试样类型：粘合剂本体 (AB) 和动态力学分析 (DMA) 试样，研究了 CP 感应固化对 2 K 环氧树脂和 2 K 聚氨酯的本体性能的影响。作者通过 92 个样品的实验程序表明，两种研究的粘合剂的热机械整体性能通过该工艺的应用发生了根本性的变化。