Patent ID: 7662907

Claim:
A method for preparing all-aromatic polyesters, which comprises: (a) subjecting the following ingredients to prepolymerization: (1) 35˜65 mole % of hydroxyl benzoic acid, (2) 0˜10 mole % of benzoquinone, (3) 15˜35 mole % of dihydroxybiphenyl, (4) 15˜35 mole % of terephthalic acid, (5) 0˜15 mole % of isophthalic acid, and (6) acetic anhydride in amount of 1.0˜1.3 times moles relative to the total hydroxyl moles contained in (1) to (5); to obtain prepolymer which is then screened through a sieve to control the particle size distribution of the resultant prepolymer as follows: 10˜39 mesh=5˜20 wt %; 40˜59 mesh=20˜40 wt %; 60˜79 mesh=40˜70 wt %; 80˜120 mesh=0˜15 wt %; (b) then subjecting the prepolymer having the above particle size distribution to a solid polymerization to obtain all-aromatic polyesters.