Patent ID: 8518527

Claim:
A method for improving the flame retardant efficiency of a phenoxyphosphazene compound, comprising the following steps: compounding a dihydrobenzoxazine ring-containing compound and the phenoxyphosphazene compound in a halogen-free flame retardant resin composition, wherein, the weight ratio between the phenoxyphosphazene compound and the dihydrobenzoxazine ring-containing compound is between 1:10 and 1:2, wherein the softening point of the phenoxyphosphazene compound is between 60° C. and 150° C.; the phenoxyphosphazene compound is a mixture of the cyclophenoxyphosphazene compounds shown with the structural formula (α) and the linear phenoxyphosphazene compounds shown with the structural formula (β), and the components comprise the following: hexaphenoxycyclotriphosphazene compound, wherein m=3, of which the weight ratio is between 70% and 90%; octaphenoxycyclotetraphosphazene compound, wherein m=4, of which the weight ratio is between 3% and 20%; and other cyclophenoxyphosphazene compounds, wherein m≧5, and the linear phenoxyphosphazene compounds, of which the weight ratio are between 1% and 10%; wherein, m represents an integer between 3 and 25; wherein, X represents —N═P(OC 6 H 5 ) 3 or —N═P(O)C 6 H 5 , and Y represents —P(OC 6 H 5 ) 4 or —P(O)(C 6 H 5 ) 2 ; n represents an integer between 3 and 100.