Flange folding/adhesive bonding with reactive hot-melt adhesive precoating

摘要

Flange folds for vehicle doors and tailgates, for sheet housings of all kinds as well as for receptacles and drums are filled with adhesives and sealants in order to increase their stability and to achieve an additional sealing effect. The use of viscous adhesives may lead to disadvantages such as an inadequate filler content, squeezing-out with soiling and finishing or necessary preheating (so-called pregelling) as protection against washing-out in dipping baths for corrosion protection. A solid, non-tacky precoating with reactive hot-melt adhesives in the joining zone of the folds ensures a defined adhesive quantity on the component, is resistant to washing-out by aqueous solutions and can be post-cured at any time by means of thermal activation, e.g. in a process-efficient and process-compatible form in drying ovens for electrophoretic painting. Furthermore, the precoating can be carried out in a method which is totally independent of the flanging process with regard to time and location.