Wesel, Germany-BYK-Chemie has developed two innovative adhesion promoters which will help paint formulators struggling to meet new challenges, the company claims.
One such challenge is the new VOC guidelines which are demanding a rapid technology shift from solvent- to water-borne systems.
One of BYK's new additives helps in a common practice currently, BYK said: overcoating an old, solvent-borne coating with an aqueous paint. "Frequently, this results in poor wet and dry adhesion," BYK points out.
BYK-4500 helps improve the adhesion of water-borne coatings even on rough-ground substrates, due to its strong pigment affinic groups (see diagram). According to Wesel-based BYK, the effect is based on a new process for which a patent is pending.
Meanwhile, BYK-4510 promotes adhesion in one-coat stoving systems for industrial coatings. The action depends on high affinity with the metal substrate and with the binder in the coating, to improve adhesion on untreated, galvanized and hot-dip galvanised steel, as well as on aluminum and other metals.
The diagram indicates how BYK-4500's groups with strong pigment affinity improve adhesion of a new to an old coating. "