Adhesives Setting by Chemical Reaction

Before setting, reactive adhesives consist predominantly of reactive low molecular mass monomers and/or oligomers that, during curing, are converted by chemical reactions into high molecular mass, often three-dimensionally cross-linked polymers. Reactive adhesives can be divided into polymerization, polyaddition, and polycondensation adhesives. Vulcanizing reactive adhesives are a special group. 

Reactive adhesives are marketed as one-pack, two-pack, and no-mix formulations. Two-pack adhesives must be completely mixed in the correct ratio before use. The mixtures have a limited pot life. One-pack adhesives are easier to handle during application. They are hardened by heat, by the catalytic action of the substrate, or by atmospheric moisture. 

To avoid mixing errors in the case of two-pack adhesives, no-mix adhesives are available. In this case, one of the surfaces to be bonded is pretreated with the adhesive resin, the other with the adhesive primer, and the bond is formed instantly when the two surfaces are brought together. 

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