Method for preparing polyether modified polycarboxylic acid grinding aid

The invention discloses a method for preparing a polyether modified polycarboxylic acid grinding aid. The method is characterized by comprising the following steps: preparing solutions from methyl allyl alcohol polyoxyethylene ether, crylic acid and vinyl acetate in a mole ratio of (1-5):(1-4):(0.1-0.3), and an initiator which accounts for 0.5-1.6% of the total mass and a chain transferring agent which accounts for 0.1-0.5 of the total mass; feeding the methyl allyl alcohol polyoxyethylene ether solution and the chain transferring agent into a reactor, mixing crylic acid and vinyl acetate, putting the mixture into a first constant-pressure liquid dropping device, and putting the initiator solution into a second constant-pressure liquid dropping device; and starting the constant-pressure liquid dropping device at 40-60 DEG C, completely dropping the liquid within 55-65 minutes, stirring to react for 30 minutes at 55-60 DEG C, heating to 85-90 DEG C to react for 10-30 minutes, cooling, and adjusting the pH value to be 7-8, thereby obtaining the polyether modified polycarboxylic acid grinding aid. The polyether modified polycarboxylic acid grinding aid is good in grinding aid and water reduction effect when used for producing universal silicate cement.