What is a silicone defoamer ?
Why can silicone work to break foam?
The defoamers must be able to reduce the surface tension to break foam in order to control foam, Compared with most other foam control materials, silicone has lower surface tension and interfacial tension, it is difficult to be dissolved by surfactants commonly used in the system. At the same time, compared with glycol-based or mineral oil-based defoamers, the toxicity is relatively low.
What are the advantages of silicone defoamers? Is it suitable for corrosive conditions?
Silicone defoamers can ensure efficient and lasting effect. Silicone defoamers are very safe. Many categories meet the requirements of the US Food and Drug Administration (FDA), the US Environmental Protection Agency (EPA), the US Department of Pesticides (USDA) and other regulations , Low surface tension, can effectively control the generation of foam in a variety of foaming materials.
There are a variety of defoamers that can perform well under various processing conditions, for example: Dow Corning 1430 defoamer is suitable for corrosive environments. In most cases, the pH of the environment can be as high as 10.
How to reasonably dilute the silicone defoamers?
Silicone defoamers emulsion must be pre-diluted with cold water (below 30 ℃). Add cold water in steps and stir thoroughly to avoid unevenly distributed lumps. If the hardness of cold water is high, it will result in uneven dilution or caking of the emulsion, both of which may cause the silicone to settle on the fabric or mechanical parts. Adding cellulose thickener thickener system can stabilize the diluted defoamer emulsion.
Since it is important to avoid the formation of spots on the fabric, how can we avoid the formation of spots on the fabric or the deposition of silicone on the equipment?
- 1.production trials and laboratory trials should be conducted to determine the minimum amount of defoamer needed to effectively suppress foam. Overdose must be avoided to achieve low cost and high performance.
- you should ensure good process conditions, such as temperature, pH, other raw materials and electrolyte concentration and shear force.
The stability of the defoamer system should be tested in the laboratory under the above conditions before being put into production. Even after dilution, the defoamer cannot be added directly to the thermal process.
What factors should be considered when choosing defoamer?
Thousands of existing chemicals can be used alone or mixed as defoamers. Therefore, before choosing an antifoaming agent, expert advice should be sought.
When selecting an antifoaming agent, a variety of variables should also be considered, mainly including regulatory requirements, product effectiveness, production costs and supplier services.
The defoamers should be rationally formulated. In addition to the foam suppression effect, it should try to reduce the impact on the product in the use environment. In general, the smaller the amount of defoamer, the lower the impact on the product.
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