Preventive Maintenance Can’t Solve Char Buildup

Preventive maintenance, which involves systematic monitoring and periodic flushing of the adhesive application system, can substantially reduce the incidence of charring and gelling and extend the life of applicator hoses and extrusion nozzles.

However, the unfortunate fact is that charring is an inherent problem with EVA-based adhesives (see previous posts). No matter how diligent the preventive maintenance program, charring will eventually occur in any hot melt system using EVA-based adhesive kept at an operating temperature above 350º for prolonged periods. Since prolonged high temperature operation naturally occurs in any production environment, char resulting from EVA will eventually pose a problem, regardless of the steps taken to prevent it. (Read more about the impact of char.)

In some cases, the maintenance required when using EVA is considered part of the cost of choosing this type of adhesive. However, in other cases, finding an alternate adhesive may address some of the drawbacks inherent with EVA-based adhesive.

Next Time:  One Solution to the Problem of Char.

(Excerpted from “No More Char”, a recent issue of Evans Adhesive Solution Advisor. Download entire issue here.)