Polyether defoamer

1. Polyether type defoamers are formed by the polymerization of ethylene oxide (EO) and propylene oxide (PO) under certain conditions, using a substance containing active hydrogen as the starting agent. According to different application fields, there are specific requirements for the binding method of EO and PO and the molecular weight of synthesized polyethers. Polyether based defoamers are widely used in industries such as cleaning, papermaking, and fermentation. Its defoaming performance is not as good as that of organic silicon, and the defoaming effect mainly occurs when the temperature exceeds the cloud point. Sometimes, in order to avoid the influence of cloud point, polyether molecules are chemically modified, which allows for wider applications.

2. Polyether modified silicone defoamer

Polyether defoamers have good water solubility, high temperature resistance, and strong alkali resistance, but the defoaming speed and suppression time are not ideal. The polyether chain is introduced into the polysiloxane chain by condensation grafting, and the polyether modified polysiloxane (commonly known as "organosilicon polyether") obtained can improve the solubility, enhance the defoaming effect, so that it not only has the advantages of organosilicon and polyether defoamers, but also has unique advantages, such as strong reverse solubility, good self emulsification, good chemical stability, and high thermal stability. In the polyether segment, the increase of the polyoxypropylene segment will improve the hydrophobicity of the copolymer, while the increase of the polyoxyethylene segment will improve its water solubility. If the ratio of polysiloxane segments to polyether segments is fixed, increasing the proportion of polyoxypropylene in the polyether chain will reduce the solubility of the copolymer in water, lower the cloud point, and generally improve its defoaming performance. Organosilicon polyether defoamers are widely used in high-temperature dyeing and fermentation processes of polyester fabrics. In addition, it can also be used for defoaming in diethanolamine desulfurization systems and various systems such as oils, cutting fluids, non freezing liquids, water-based inks, etc. It is also suitable for defoaming of uncured resin after plate making with photosensitive resin in the printing industry. It is a representative, high-performance, and widely used organosilicon defoamer.