| Selection Guidelines
InChem Phenoxy Resins can be
used as the sole resin vehicle in adhesives formulations.
For
crosslinked systems using the pendant secondary hydroxyls
on the Phenoxy backbone, it is recommended to empirically
determine the best level of crosslinker for a balance of
coatings properties such as hardness and flexibility. Usually
the level of crosslinker or hardener is about 10 to 15 phr
(parts per hundred) on a solids basis.
Typical crosslinkers
used in thermoset applications are melamine-formaldehyde
resins, phenolics, blocked isocyanates, and polycarboxylic
acids. InChem now provides a phenolic crosslinker called
InChem Resin PR-65 useful for thermoset coatings and adhesives
based on hydroxyl functional vehicles like solid grade epoxies,
OH-functional polyesters, and Phenoxy resins.
In hot melt applications with thermoplastic
urethanes (TPU’s) and copolyethylene 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 powder
grades of Phenoxy are easy to incorporate. Alternatively,
the liquid and solid blends offered by InChem 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. |
