The phenoxy resin is an excellent adhesive/tie layer between multi-layer composites such as automotive headliners, food packaging films, graphic art substrates, laminated non-wovens, and other laminated substrates. Structural adhesives are enhanced and strengthened by the phenoxy resin as it acts as both an adhesion promotor and flexibilizer in rigid epoxy and epoxy-urethane systems. The presence of phenoxy reduces stress cracks and increases bond strength between substrates.
- Container / Packaging
- Construction
- Structural – One & Two Component
Adhesive Formulations
In adhesive applications, Phlex Tek phenoxy based resins offer a wide selection for your chosen technology. Phenoxy resins are used to add superior adhesion promotion to a wide variety of substrates. The large number of secondary hydroxyls give phenoxy the “bite” that many systems require. The linear thermoplastic nature of phenoxy provides flexibility to rigid cross-linked systems.
Phenoxy resins find use in aerospace and automotive latent cure and hotmelt adhesives by improving adhesion and flexibility of epoxy-based compounds, and circuit board laminating adhesives by increasing bond strength to the boards.
Phlex Tek phenoxy resins can be used as the sole resin vehicle in adhesives formulations. For cross-linked systems using the pendant secondary hydroxyls on the phenoxy backbone it is recommend to empirically determine the best levels of cross-linker for a balance of coatings properties such as hardness and flexibility. Usually the level of cross-linker or hardener is about 10 to 15 phr (parts per hundred) on a solids basis. Typical cross-linkers used in thermoset applications are melamine-formaldehyde resins, phenolics, blocked isocyanides, and polycarboxylic acids.
In hot melt applications with thermoplastic urethanes (TPU’s) and co-polyethylene vinyl acetate resins (EVA’s) phenoxy resins can be incorporated at levels as low as 10% to act as antiplastizers imparting properties such as stiffness and cohesive strength.
For modifying epoxy systems, the power grades of phenoxy are easy to incorporate. Alternatively, the liquid and solid blends offered by Phlex Tek provide a “user friendly” avenue. Phenoxy behaves as a “hard plasticizer” in many epoxy matrices used as adhesives by interpenetration. In acid cured and anhydride-cured systems, phenoxy may partially tie into the cured matrix.