Hotmelt Adhesives can be formulated using several different base polymers.
The choice of polymer influences the adhesion, temperature resistance, chemical resistance and the cost.
FOSPAT use several different polymers which enable us to formulate a large range of useful properties into FOSPAT hotmelt adhesives.
Ethylene Vinyl Acetate (EVA)
This is one of the most popular base polymers for hotmelt adhesives, and is used in both packaging and product assembly formulations. It is economical and provides service temperatures of -30ºC to 80ºC.
Polyamide (PA)
A higher performance polymer that is used to formulate adhesives with better resistance to temperature extremes; typically -60ºC to 130ºC. These adhesives are more chemical resistant but tend to be slightly less sticky than adhesives that are based on EVA.
Polypropylene (PP)
These are used to formulate adhesives with specific adhesion properties and delayed setting time. They are often used for spray formulations. Service temperatures are -30º to 110ºC depending on the formulation.
Polyurethane (PUR)
FOSPAT Polyurethane Reactive Hotmelt can be applied, and initially sets, like a normal Hotmelt Adhesive by losing heat and becoming solid. The PUR absorbs a small amount of moisture from the surrounding materials or atmosphere and cross links.
This is a permanent chemical change that takes several days and increases heat and chemical resistance.
A small amount of moisture is required for this reaction to take place. Therefore, it is better if at least one substrate is porous. If moisture is only available from the edge of the bond then cross linking will be slow and unreliable.
More water shouldn’t be applied to a surface before bonding as this will overwhelm the reactive component of the adhesive and stop cross linking.
FOSPAT PUR is packed in individual foil packs and comes with a shelf life of at least 6 months.