How to make defoamer?

Defoamer are mainly used to eliminate excessive foam that occurs during industrial production and manufacturing, and to prevent excessive foam from affecting industrial production and product quality. Because defoamer need to be used in different industries, their formulas and The ingredients are also different.

Defoamer ingredients and formulas

Testing in aqueous solutions showed that the defoaming effect of alcohol is related to its solubility and diffusion in the foaming liquid. C7~C9 alcohols are the most effective defoamer.

C12~C22 high-carbon alcohols are formulated with appropriate emulsifiers into water emulsions with a particle size of 4~9 μm and a content of 20~50%, which are defoamer for water systems.

1. Silicon

The most commonly used is polydimethylsiloxane, also known as dimethicone. It has low surface energy, low surface tension, low solubility in water and general oil, and high activity. Its main chain is a silicon-oxygen bond and it is a non-polar molecule. It has no affinity with the polar solvent water and has little affinity with general oils. It is low-volatility and chemically inert, relatively stable and less toxic. Pure polydimethylsiloxane cannot be used as a defoamer without dispersion treatment. This may be due to its high interfacial tension with water and low spreading coefficient, making it difficult to disperse in the foaming medium. Therefore, the composite formed by mixing silicone oil into SiO2 aerosol can be obtained by mixing the hydrophobically treated SiO2 aerosol into dimethyl silicone oil and processing it at a certain temperature and for a certain time.

Defoamer can be roughly divided into two categories: one type can eliminate the generated bubbles, such as ethanol, etc.; the other type can inhibit the formation of bubbles, such as emulsified silicone oil, etc. Defoamer approved for use in China include emulsified silicone oil, high-carbon alcohol fatty acid ester complex, polyoxyethylene polyoxypropylene pentaerythritol ether, polyoxyethylene polyoxypropylene amine ether, polyoxypropylene glyceryl ether and polyoxypropylene.

2. Polyether modified silicon

It combines the advantages of polyether and silicone deofamer.It is non-toxic and harmless to bacteria and has a very small amount of addition. It is a cost-effective product.

Polyether modified silicone is a polyether-siloxane copolymer (referred to as silicon ether copolymer) made from polyether segments in the siloxane molecule. Polysiloxane defoamer has the characteristics of rapid defoaming, long foam suppression time and safety and non-toxicity. However, it is difficult to dissolve in water, has high temperature resistance and poor resistance to strong alkali. Polyether defoamer has good water solubility and resistance to strong alkali. It has high temperature resistance and strong alkali resistance, but its defoaming speed and foam suppression time are not ideal. The polyether chain is introduced into the polysiloxane chain through grafting through condensation technology, so that it has the advantages of a second-class defoamer. It has become a defoamer with excellent performance and wide application prospects.

3. Polysiloxane defoamer

Polysiloxane defoamer is usually composed of two main components: polydimethylsiloxane and silica.

In fact, when targeting defoaming in different industries, relative adjustments have been made to them. Adjustments are made to their main components so that they can meet the defoaming performance of different industries and thereby improve their defoaming performance. The anti-foaming performance is better exerted in the foaming liquid.