Environmental Aspects Of EVA Hot-melt Adhesives

An increasing number of books and booklets are being produced using the EVA hot-melt adhesive perfect binding process. This method is employed by processing plants of all sizes across the country and is trending upward in popularity due to advantages such as rapid production, short turnaround times, attractive finished appearance, and the elimination of several processing steps. However, printing plants-often eager to launch operations and maximize their workload-frequently overlook the technical requirements regarding the environment and conditions for using hot-melt adhesives, leading to various processing issues.

The Impact of Production Facility Temperature and Humidity

EVA hot-melt adhesive is a thermoplastic adhesive; its "open time" (the window during which the adhesive remains workable after application) is influenced by indoor temperature and humidity. Ideally, the indoor temperature (i.e., within the workshop) should be kept constant-optimally between 15°C and 26°C-and humidity maintained at approximately 50%. However, it is rare for facilities using hot-melt adhesives to meet these standards. Consequently, many regions experience recurring problems: in summer, excessive bubbling occurs, and the adhesive fails to cure or cool properly; conversely, in winter, the curing and cooling times shorten drastically, resulting in weak bonds, adhesion failure, or books breaking apart after binding. In some regions, high humidity prevents the books from setting their shape after the cover is attached, making subsequent trimming impossible. All these issues are directly linked to the temperature and humidity of the production facility.