Method of Preparing Wholly Aromatic Polyester

A method of preparing high heat resistant wholly aromatic polyester comprising:

• a) mixing para hydroxy benzoic acid, biphenol and terephtalic acid with anhydrous acetic acid as an acylating agent;
• b) removing byproduts, discharging products, and pulverizing the discharged products;
• c) introducing pulverized low molecular weight polymers into a solid state reactor and elevating the temperature to a weight loss initiating temperature;
• and
• d) performing a solid state reaction by elevating the temperature from the weight loss initiating temperature to a melting point.

A method of preparing wholly aromatic polyester resin comprising:

• a) polymerizing at least two components selected from the group consisting of para hydroxy benzoic acid, biphenol, terephtalic acid, and isophthalic acid, and anhydrous acetic acid, removing byproducts, pulverizing products, and solid state polymerizing the pulverized polymer;
• b) mixing 100 parts by weight of a resin mixture comprising 100 parts by weight of a high heat resistant liquid crystal polyester resin A having the melting point of 350 to 450° C. and 10 to 100 parts by weight of a high heat resistant liquid crystal polyester resin B having the melting point of 310 to 400° C. obtained in operation a), with 10 to 150 parts by weight of an inorganic filler, wherein the difference of the melting points between the high heat resistant liquid crystal polyester resin A and the high heat resistant liquid crystal polyester resin B is in the range of 10 to 70° C.;
• c) extruding and pelleting the mixture;
• and
• d) molding the mixture.