Reactive Adhesives

Because Kratonź polymers are thermoplastic, they have limited solvent resistance and they loose cohesive strength at temperatures above about 70șC. If the Kraton polymer is crosslinked after the adhesive is applied, the adhesive will have better solvent resistance and it will maintain cohesive strength at up to about 150șC. With the Kraton D and Kraton G polymers, crosslinking can be accomplished with a sulfur based vulcanization package or by a free radical reaction initiated by peroxide or by high energy radiation (UV or EB for example). With Kraton FG polymers, chemical cure can be accomplished with isocyanates, melamine resins, epoxy resins or organo-metallic compounds.

Features and Benefits

Crosslinking converts Kraton polymers from being thermoplastic to being flexible thermoset. The primary benefits are that crosslinking improves the solvent resistance and the shear strength of the adhesive at elevated temperatures.

Products

Tapes: By crosslinking the adhesive after it is applied to the backing, tape manufacturers can improve the ability of their pressure sensitive adhesives to bear a load at elevated temperatures.

Coatings: Coating manufacturers can improve the resistance of their coating based on a Kraton FG polymer to casual contact with solvents by crosslinking the polymer with an isocyanate in an ambient temperature cure or with a melamine resin in a bake cure system.

Oil Gels: Thermoset oil gels based on a Kraton D polymer can be made which maintain their shape even at temperatures up to about 150șC by crosslinking the polymer with a free radical reaction, frequently initiated by exposure to UV radiation.