Process for preparing a polyether ether ketone

A preparation method for a PEEK (polyether ether ketone) product, characterized by using Na2CO3 as the only condensing agent and adopting the addition of hydroquinone step by step, and particularly comprising the following steps that:

• (1) during continuous stirring, the solvent of diphenyl sulfone is quickly added to a reactor and is then heated until dissolved, 4,4′-difluorobenzophenone, hydroquinone and diphenol biphenyl are sequentially added, wherein 4,4′-difluorobenzophenone/(hydroquinone+diphenol biphenyl)=1:1.1-1:1.2 (mol ratio), and another substance can only be added after the dissolution of the previous substance with regard to each addition of one substance;
• (2) pre-dried anhydrous sodium carbonate is crushed and screened and is then quickly added to a reaction system according to the mol ratio of 4,4′-difluorobenzophenone/sodium carbonate of 1:1-1:3 to be continuously stirred for 30 to 50 minutes under 150 to 160° C. until phenol and sodium carbonate in the reaction system react to form sodium salts, the reaction temperature is then increased to 190 to 195° C., the formed sodium salts carry out polymerization reaction with the 4,4′-difluorobenzophenone for 30 to 50 minutes, the temperature of the reaction system is increased to 300 to 320° C. within 10 minutes, and therefore the reaction speed is increased and the viscosity is enhanced;
• (3) when the reaction is carried out for 1 to 1.5 hours and the viscosity of the system has little changes, the reaction temperature is increased to 320 to 330° C., hydroquinone is immediately added to the reaction system once again according to the mol ratio of 4,4′-difluorobenzophenone/hydroquinone of 1:0.01 to 1:0.5, the viscosity of the reaction system is quickly enhanced, the stirring is speeded up at the same time, and the heating is stopped after the reaction is carried out for 1 to 2 hours;
• (4) finally, polymer viscous solution is directly and quickly poured into ice water to cool the product into a bulky solid, and the PEEK product is obtained through crushing, ethanol washing and drying of the bulky solid.