Selected aspects of epoxy adhesive compositions curing process

摘要

The paper focuses on selected parameters of curing process - temperature and time. The tests aimed at evaluating the impact of short-term thermal recuring on 1050A and 2017A aluminium alloy sheet adhesive joints strength. Joints were formed with two different adhe-sives, the main component of which was in both cases epoxy resin Epidian 53 and two different cure agents - poliamineamide C (PAC) and triethylenetetraamine (PF) curing agents. Curing conditions - first curing time, recuring time and recuring temperature - were modified for each of the four tests conducted. For the sake of comparative analysis, adhesive joints were subjected to a single-stage cure cycle at ambient temperature. A two-stage cure cycle of both Epidian 53 compositions at 80 °C for 1 and 2 h produces a material of different mechanical properties than the same material which submits a single-stage cure cycle at ambient temperature, as well as at 60 °C for 30 min. Simultaneously, Epidian 53/ PF/100:50 composition proves to produce higher joint strength after recuring than Epidian 53/PAC/l 00:80; the strength of a joint formed with the former composition increases up to 50% when compared with joints subjected to a single-stage cure cycle. Moreover, tests show that recuring of the adhesive joint formed with both compositions at 60 °C for 30 min does not have a considerable influence on either 1050A or 2017A aluminium adhesive joint strength.