Preparation method of defoaming agent for waterborne system

Abstract

The invention relates to a preparation method of a defoaming agent for a waterborne system. The preparation method of the defoaming agent for the waterborne system comprises the following steps: a) adding silicon oil, gaseous silicon dioxide and catalyst into a reaction container according to proportions, and preparing silicon cream under an agitating condition protected by nitrogen; b) adding hydrogen-containing silicon oil and allyl polyether into the reaction container, agitating under the protection of nitrogen, increasing temperature and adding an initiator for reaction to obtain polyether modified organic silicon; c) jading the silicon cream obtained in step a), the polyether modified organic silicon obtained in step b) and an emulsifier into the reaction container, adding water for emulsification under a high-speed agitating condition, and adding a thickening agent to regulate viscosity to obtain a product. The defoaming agent prepared by adopting the preparation method provided by the invention has the advantages that the active components are low, the manufacturing cost is low and the environmental friendliness is better; the emulsification is stable, the compatibility in the waterborne system is good, the defoaming agent is easy to disperse, the surface tension is low, the defoaming speed is quick, the foam inhibiting time is long, the thermal resistance, shear resistance and acid and alkali resistance thereof are good, and the defoaming agent can adapt to various places; the defoaming agent can be separately used and can also be jointly used with other adjuvants, the stability is good, the phenomenon of oil floating due to demulsification does not occur, no sediment is produced and shrinkage cavities during coating are not caused; and the defoaming agent is also very effective to non-waterborne systems.

Description

technical field [0001] The invention belongs to the field of fine chemical additives, and relates to a water-based defoamer, in particular to a modified silicone defoamer for water-based coatings. Background technique [0002] With the enhancement of human environmental protection awareness, especially in 2015, my country began to levy paint consumption tax and furniture industry "pollution charge", which directly expanded the application range of water-based paint in industrial paint. Water-based coatings often need to add a certain amount of surfactants in the industrial production process to meet the special requirements of the solution system in aspects such as cleaning and lubrication. The solution system with surfactant is easy to produce a large amount of foam due to factors such as gas or stirring. If these foams are not eliminated, it will affect the construction of the paint and the quality of the paint itself. For example, in the color paste, it must be adsorbed o...

AI Technical Summary

Problems solved by technology

But it has a fatal shortcoming, which is the low foam breaking rate. Once a large amount of foam is generated, the polyether defoamer cannot effectively eliminate the foam at once, and a certain amount of defoamer needs to be added to slowly solve the problem.

Images