The suspending agent auxiliary agent is composed of dispersant and wetting agent in the ratio of 1:10-10:1. The preparation method comprises the following steps:
(1) The phenylethyl phenol formaldehyde resin is added into a polymerization kettle, then the catalyst is added, and the nitrogen is blown for vacuum dehydration;
(2) The ethylene oxide is continuously injected at 140~170 ℃. After that, small molecules and volatile matter are removed by aging and decompression, and then neutralized when the temperature is lower than 100 ℃ to generate phenylethyl phenol formaldehyde resin polyoxyethylene ether;
(3) The product is esterified with an esterification agent;
(4) After the esterification reaction is completed, neutralize it with organic base. When the pH value reaches 6~8, remove the water, and filter it to obtain the dispersant.
(5) Mix the dispersant and wetting agent prepared in the above steps in proportion.