Structural adhesives require high performance additives that can positively impact how they are assembled and used.
Our specialty carbon blacks and fumed silica products can provide sag resistance in adhesive beads which increase bond line dimensional stability until cure, as well as add reinforcement to increase cohesive strength. Structural adhesives that benefit from our additives include those used for structural bonding, pressure sensitive adhesives, and elastic bonding and sealing.
Our specialty carbon blacks and fumed silicas impart act as thixotropic additives to epoxy and urethane structural adhesives. We support customers' formulations for many applications including structural automotive, aerospace, construction and more. The reduction of adhesive viscosity under shear facilitates pumping, mixing and application of the adhesive and assures adhesive bead stability until completion of cure. During storage, fumed silica reduces settling for fillers. Highly hydrophobic silicas are often a good choice to improve viscosity storage stability in epoxy adhesives, such as those used in wind blade manufacturing. In the cured adhesive, carbon black and silica products can provide reinforcement of the polymer which increases cohesive strength.
Elastic bonding and sealing
Additionally, our specialty carbon blacks and silicas impart thixotropy to urethane, butyl and silyl-terminated polymer adhesives and sealants. This shear-thinning behavior facilitates pumping, mixing and application of the adhesive and assures adhesive bead stability and bond line dimensional stability until completion of cure. During storage, fumed silica reduces settling of fillers. In the cured adhesive, carbon black and silica provide reinforcement of the polymer to increase modulus and elongation. Hydrophobic silicas promote shelf-stability in one-component moisture-curing systems. The refractive index of fumed silica is similar to that of many polymers, allowing formulation of transparent adhesives.