Silicone defoamer is a white viscous emulsion that is mainly used to eliminate foam formed by materials during the production process. As an indispensable additive in the production process of chemical industry, paper making, coating, food, textile, pharmaceutical and other industrial sectors, silicone defoamer has been paid more and more attention by all walks of life. Today, Cheng Cheng Xiaobian will give you a brief introduction to the relevant knowledge and testing standards of silicone defoamer.



The current standard for silicone defoamer is "GB/T 26527-2011 Silicone defoamer", the 2024 version of the standard has been published on April 25, 2024, and will be implemented from November 1, 2024. The 2024 version of the standard mainly changes part of the technical requirements, and adds the technical requirements of modified silicone defoamer and the test method of partial defoamer performance.


This standard is mainly applicable to silicone defoamer made of polyorganosiloxane or modified polyorganosiloxane as the active body, and is not applicable to silicone defoamer in food and pharmaceutical industry. The common organosilicon defoamer is made of polyorganosiloxane as the active body and supplemented by other auxiliaries. Modified silicone defoamer is a kind of silicone defoamer made from polyether and/or alkyl modified polyorganosiloxane and supplemented by other additives.

According to the different forms of preparations, silicone defoamer is mainly divided into three categories: intrinsic type, emulsion type and solid type, of which solid type is divided into airborne type and non-airborne type.








This type of defoamer is mainly composed of organic silicon defoamer active ingredients, which can be dispersed in the aqueous phase system and does not contain water.








Emulsion type is an oil-in-water emulsion type defoamer which can be dispersed in water phase system and is prepared by emulsifying the active ingredients of silicone defoamer.








Solid type is a solid form of defoamer made of organic matter such as starch or inorganic matter such as inorganic salt by adsorption of organic silicon defoamer active ingredients.








The technical requirements of ordinary silicone defoamer and modified silicone defoamer are basically the same, mainly including appearance, pH, stability, defoamer performance and solid content. The main difference is that the defoaming performance of ordinary silicone defoaming agent uses hand shaking method and vertical oscillation method, the defoaming performance uses air drum method, and the defoaming performance of modified silicone defoaming agent uses high-speed dispersion method.