Adhesive Char Solutions – The Benefits of Metallocene

char adhesive


Adhesive char is a pervasive issue in all industries that rely on hot melt adhesive. Char buildup in adhesive applicators can cause clogs, uneven adhesive application and ultimately production delays as the problem is addressed through maintenance.

According to AdhesiveMag.com, char buildup can show up at many stages of the application process. Adhesive char:

  • Clogs filters
  • Stops up spray nozzles
  • Clogs bead nozzles
  • Works its way onto the substrate, leaving marks, streaks and uneven surfaces
  • Eventually works its way into pumps, breaking seals and scoring and damaging the pump walls

But even before these pervasive issues arise, char can be a significant problem. Before clogging even occurs and charring is even apparent, carbon char in hose linings creates a thermal barrier. This lowers the optimal operating temperature of the adhesive, causing poor flow performance.

And unfortunately, these problems are inherent to any adhesive process that includes the use of EVA-based hot melt adhesives. No matter how regular your maintenance schedule, adhesive char will almost inevitably occur.

Metallocene solutions to adhesive char

Fortunately, metallocene-based hot melt adhesives offer key advantages to traditional EVA-based hot melt adhesives:

  • Char-free operation: Thanks to its chemical competition, a metallocene-based hot melt adhesive is not subject to the carbon buildup, gelling or other changes common to other adhesives throughout extended high-temperature storage and use.
  • Improved mileage: Metallocene-based adhesives have a lower density than traditional EVA-based adhesives and can be applied at lower flow rates. As a result, metallocene-based adhesives often yield up to a 40% reduction in adhesive use.
  • Precision application: The lower viscosity of metallocene-based adhesives during their pot life means operators have more precise control over flow, bead size, and bead quality.
  • Diverse performance: Metallocene-based adhesive outperforms EVA-based adhesives in both high- and low-temperature performance, achieving superior bonding strength in both high temperature and freezing cold. This superior performance also applies to package stocks. Metallocene-based hot melts pair well with a wide variety of coated and uncoated paper packaging and corrugated stock. They are also ideal adhesives for heavy ink surfaces.

Affordable solutions to adhesive char

On top of its functional benefits, metallocene-based hot melt offers significant financial benefits as well. In many applications, a metallocene-based adhesive can be a more affordable choice than a traditional EVA-based adhesive.

And given the wide range of options offered by Evans Adhesive, there’s likely a perfect metallocene-based adhesive for your application.

Contact Evans Adhesive for more information on how a metallocene-based adhesive can be customized to meet your needs, and see our informational download No More Char here for more solutions to adhesive char.