Acrylic graft copolymers free glycidyl groups-glycidyl methacrylate(GMA)
TGIC Replacement chemistries
Acrylic graft copolymers containing free glycidyl groups
These hardeners,which include glycidyl methacrylate(GMA) curatives have recently been promoted as crosslinkers for carboxy polyester. Since the cure mechanism is an addition reaction, film builds that exceed 3 mils(75 um) are possible. So far, accelerated weathering tests of polyester GMA combinations indicate results similar to those of TGIC.
Some formulating problems exist when acrylic graft copolymers are used ,for example, flow and leveling properties are relatively poor. New carboxy polyester are being developed for this chemistry, however, and some resins made originally for HAA curatives seem to improve flow properties when they are combined with GMA curatives. It’s important not to confuse this type of curative with GMA acrylic / dibasic acid combinations,which are not compatible with conventional electrostatic powder coating system.