Defoaming agent for coating and ink emulsion and preparation method of defoaming agent

The invention belongs to the technical field of fine chemical assistants, and particularly relates to a defoaming agent for water-based paint and ink emulsion and a preparation method of the defoaming agent. The method comprises the following steps: firstly, carrying out hydrosilylation reaction on hydrogen-containing silicone oil, EO/PO block or random allyl polyether and long-chain alkyl olefin to prepare long-chain alkane and polyether composite modified silicone oil; after the addition reaction, adding modified fumed silica to obtain silicon paste. finally, mixing span 80, Tween 80, carboxymethyl cellulose sodium, a thickening agent and the silicon paste; and after adding water, emulsifying and dispersing at a high speed to prepare the defoaming agent. According to the method, an organic solvent does not need to be added, the preparation method is simple, and the obtained defoaming agent is short in defoaming time, long in foam inhibition time and free of floating oil by regulating and controlling the mol