Abstract
Phenoxy phosphazene is widely known as a halogen free flame retardant used for printed circuit board materials. However, it posses the property of reducing thermal resistance of a total resin system as a typical problem originating in a miscible type flame retardant.
We found the way to reduce the solubility of the ring phenoxy phosphazene molecules in the matrix resin by incorporating immiscible functional moieties with them. As a result, an immiscible phase diagram area was confirmed to exist, where the above mentioned functionalized ring phenoxy phosphazene was immiscible in the matrix resin. Moreover, we demonstrated that the technique worked well as a means for overcoming the drawback of the miscible type flame retardant systems.
