There are many types of foams to be laminated in packaging applications. Custom packaging and foam fabricators wrestle with the bonding questions regarding hot melts and hot melt equipment every day.
The range of foams and substrates they are laminated to require many different type of hot melts and different types of hot melt systems to apply these hot melts.
Some of the standard hot melts used are pressure sensitives (PSA) , polyolefins (APAO), ethyl vynil acetates (EVA). Each hot melt offers different bond capabilities. Each hot melt has different viscosities and softening points for temperature resistance requiring different application methods. Some need to be applied at a higher temperature and laminated fast and others remain “Open” and can be assemble long after the application.
Most customers consider the use of hot melt for bonding foam materials because these products accelerate the production process. The standard method of applying hot melts is in bead form and unfortunately from a stick gun in many cases. Often the hot melt in bead form burns into the foam decreasing the laminated area of contact between the two substrates.
Optional methods of hot melt application that are used worldwide by foam fabricators are spray, swirl, fiberization and rollcoating. These methods allow you to apply a longer open time hot melts very fast to a temperature sensitive foams or open cell foam and not affect the surface negatively. The longer open time simply gives you more time to work with the adhesive because it is being applied in a thin pattern to foam.
All substrates should be evaluated with the proposed hot melt and application method to ensure that the adhesive and application system meet you production and quality requirements.
For more information call or email Pierce Covert,
Glue Machinery Corporation