01 Textile Printing and Dyeing

02 Petrochemical Industry

(1) Drilling: Ethyl silicone oil (or methyl silicone oil layer emulsion) is used as a mud additive.
(2) Oil Production: For oil-gas separation, use defoaming rods. The melting point is 2.8¬13.9℃ higher than the temperature of the wellhead foam.
(3) Natural Gasoline Absorption: Prepare a 2% solution of dimethyl silicone oil with gasoline.
(4) Oil-gas Separation and Demulsification:
A. For oil-gas separation, adding 0.025～0.0065mg/Kg to the crude oil can improve the production capacity;
B. For demulsification: The crude oil separated from oil and gas is generally a W/O type emulsion. Adding about 0.2mg/Kg of a suitable antifoaming agent can achieve the effect of demulsification and defoaming.
(5) Refining: Adding an antifoaming agent during vacuum distillation can improve the color of the fraction and broaden the fraction range. Commonly used is a diesel oil solution of silicone oil.
(6) High-energy Fuels (Internal Combustion, Jet, Aviation Fuels): Disperse cyanoalkyl polysiloxane in high-flash-point kerosene and then add it to high-energy fuels as an efficient antifoaming agent.
(7) Asphalt and Residual Oil: The amount of added silicone oil is 0.2×10－6～2.0×10－6.
(8) Delayed Coking, Coke Removal and Scale Removal: The reference addition amount of the antifoaming agent is 0.05～100×10－6.
(9) Defoaming Drilling Fluid: High-viscosity sulfonate metal salt (calcium petroleum sulfonate : sodium sulfonated asphalt = 1:1). The addition amount of siloxane is about 100～400×10－6 or 5～15mg/Kg. It is better that the ratio of sulfonate to siloxane is close to 1:1.
(10) Lubricating Oil: Such as internal combustion engine oil, automotive lubricant, metal working fluid, compressor oil, etc. When silicone oil is added as an antifoaming agent, it is because of the following advantages:
A. It is difficult to dissolve in lubricating oil and exists in a dispersed state, which is beneficial for adsorption on the bubble film to break the bubbles;
B. It has an alkyl group similar to that of mineral oil and can squeeze into the bubble film to weaken the molecular attraction;
C. It has a low surface tension, good permeability. When adsorbed on the surface of the bubble film, it reduces the local surface tension. The bubble breaks due to the uneven surface tension of the bubble film. For heavy oil, select silicone oil with low viscosity, and the addition amount is 1～10×10－6. In addition, alkyl polyacrylate is also quite good and has better gas release properties. Add branched-chain amines to naphtha and then add it to the lubricating oil, which can also be used as an antifoaming agent. The addition amount is 0.05～1%. This antifoaming agent can be added to metal cutting fluids.

03 Papermaking Industry

(1) Pulping: Use silicone emulsion antifoaming agent (90g/T paper).
(2) Coated Paper: For the coating of coated paper, such as the paper used for printing pictorials after calendering, non-silicone antifoaming agents are generally used for the coating bubbles.
(3) Sewage Treatment: Use water-emulsion type silicone antifoaming agent.

04 Applications in Coatings and Inks

I. Requirements for Antifoaming Agents in Coating Production:
(1) It has a certain affinity with the active substances on the surface of the foam, but it should be difficult to dissolve or insoluble in the bubble liquid;
(2) Its surface tension is lower than that of the bubble liquid, and it has a lower HLB value;
(3) It should stabilize the emulsion (latex);
(4) After the coating forms a film, it should not cause adverse consequences such as fish eyes and craters;
(5) Antifoaming Agents for Water-based Coatings: Substances that are difficult to dissolve in water are mostly used, such as mineral oil, higher alcohols, silicone resins. Silicone is the best antifoaming agent for water-based coatings. Antifoaming Agents for Non-water-based Coatings: Substances that are difficult to dissolve in organic solvents are commonly used, such as lower alcohols, silicone resins (the amount of silicone resin should be appropriate. Excessive amount is likely to cause shrinkage cracks and pits. Now modified silicone resins or emulsified silicone resins are mostly used).
II. Recommended Silicone Antifoaming Agents for Water-based Coatings:
(1) Mixture of Silicone Oil and Hydrophobic SiO2
Suitable for: Epoxy resin, casting, with a dosage of 0.3%; Thermoplastic acrylic resin, spraying, with a dosage of 0.3%.
(2) Mixture of Polyether Polysiloxane and Hydrophobic SiO2
Suitable for: Thermosetting alkyd resin, dipping, with a dosage of 0.3%, scraping, with a dosage of 0.1%.
(3) Mixture of Hydrophobic SiO2, Hydrocarbons and Silicone Oil
Suitable for: Thermoplastic acrylic resin, printing, ink, with a dosage of 0.1%; Air-drying acrylic resin, casting, with a dosage of 0.5%.
(4) Emulsion of Mixture of Silicone Oil and Hydrophobic SiO2
Suitable for: Alkyd-modified styrene-acrylic resin, casting, with a dosage of 0.5%.

05 Silicone Antifoaming Agents for Detergent Industry

Polysiloxane and modified sodium tripolyphosphate are used as additives for powdered detergents. An emulsion of dimethyl silicone oil (1500c.s) with a SiO2 content of 2～6% is mixed with anhydrous sodium tripolyphosphate, and the amount of the emulsion used is 10～40% to form a hydrate as an additive. For metal cleaning solutions, they are required to be alkali-resistant. It is best that the liquid product is transparent and has defoaming activity when added.
06 Silicone Antifoaming Agents for Food Industry
Food-specific polysiloxane resin: Mainly composed of dimethyl polysiloxane, with a SiO2 content of less than 15%. When the food is an aqueous solution, use the emulsified product. For other cases, the oil-based product can be used directly, and the dosage should be controlled.