Today we are going to talk about defoaming agents that destroy foam, prevent excessive foam formation or prevent bubbles from developing too strongly. If you are interested in this topic, read on to learn more.
- 1 Why can silicone help break down foam?
- 2 What are the advantages of silicone foam control formulations?
- 3 How reasonably dilute silicone foam control formulations?
- 4 How to avoid stains on fabrics or silicone deposits on equipment?
- 5 What factors should be considered when selecting a silicone foam control formulation?
Why can silicone help break down foam?
Defoamers must be able to reduce the surface tension to break down foam in order to control it. Compared to most other foam control materials, silicone has a lower surface tension and interfacial tension, and it is difficult to be dissolved by surfactants commonly used in the system. At the same time, compared to glycol or mineral oil-based defoamers, toxicity is relatively low.
What are the advantages of silicone foam control formulations?
Silicone antifoam can guarantee an effective and long-lasting effect. Silicone defoamers are very safe. With low surface tension, they 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.
How reasonably dilute silicone foam control formulations?
Silicone antifoam emulsion should be pre-diluted with cold water (below 30 ℃). Add the cold water in stages and stir well to avoid poorly distributed lumps. If the hardness of the cold water is high, it will result in dilution or uneven curing of the emulsion, both of which can cause the silicone to stick to fabric or mechanical parts. The addition of a cellulose-based thickening system can stabilize the diluted antifoam emulsion.
How to avoid stains on fabrics or silicone deposits on equipment?
First of all, we recommend that you perform production and laboratory tests to determine the minimum amount of defoamer needed to effectively suppress foam. Overdosing must be avoided to achieve low cost and high performance. You must ensure proper process conditions such as temperature, pH, concentration of other raw materials and electrolyte, and shear strength. The stability of the antifoam system should be tested in the laboratory under the above conditions before it is put into production. Even after dilution, the defoamer cannot be added directly to the thermal process.
What factors should be considered when selecting a silicone foam control formulation?
Thousands of existing chemicals can be used alone or mixed together as antifoam agents. Therefore, before selecting an antifoam agent, it is important to be well informed. When selecting an antifoam agent, a series of variables should also be considered, primarily regulatory requirements, product efficacy, production costs and supplier services. Defoamers must be rationally formulated. In addition to the foam suppression effect, attempts should be made to reduce the impact of the product in the environment of use. In general, the lower the amount of defoamer, the lower the impact on the product.
If you want to know more about the use and selection of silicone antifoam products, you can contact Elkem. Elkem has more than 60 years of expertise and offers a wide range of silicone antifoam products to meet a wide variety of requirements and needs.