Silicone defoamer is a commonly used chemical substance in a wide range of applications. Its main role is to reduce or eliminate the formation of air bubbles in the liquid, thus improving the stability and quality of the liquid. The following small talk about the application of silicone antifoam agent.
A textile printing and dyeing
01 sizing process: aqueous emulsion type silicone defoamer, such as: silicone polyether, sizing tank additive amount of 0.2 ¬ 0.25g / L
02 chemical fiber oil additive: chemical fiber oil add 0.02 ¬ 0.04% water emulsion type defoamer. Chemical fiber oil agent formula should contain organic silicone oil.
03 desizing and refining: choose to contain polyether silicone.
04 bleaching: more acidic, silicone defoamer.
05 Dyeing: silicone emulsion defoamer. Spray dyeing is best to use polyether silicone, high temperature defoaming, low temperature water soluble, non-staining fabric.
II Petrochemical industry
01 Drilling: Ethyl Silicone Oil (or Methyl Silicone Layer Emulsion) for mud additive.
02 Oil extraction: oil and gas separation, defoamer rod. The melting point is 2.8¬13.9℃ higher than the wellhead foam temperature.
03 Natural gasoline absorption: Dimethicone oil is prepared into 2% solution with gasoline.
04 Oil and gas separation emulsion breaking:
A. Oil and gas separation: adding 0.025～0.0065mg/Kg in crude oil can increase production capacity;
B. Breaking emulsion: oil and gas separation of crude oil is generally micro-W/O emulsion, add 0.2mg/Kg or so of the appropriate antifoam agent, can achieve the effect of breaking emulsion and defoaming.
05 refining: decompression distillation add antifoaming agent, fraction color improvement, fraction range relaxation, commonly used in diesel oil solution with silicone oil.
06 high-energy fuels (internal combustion, jet, aviation fuel) with cyanoalkyl polysiloxanes dispersed in high flash point kerosene, and then added to high-energy fuels as a highly effective antifoaming agent.
07 asphalt, residual oil: add silicone oil amount of 0.2 × 10-6 ~ 2.0 × 10-6
08 Delayed coking, decoking, descaling: defoamer added reference amount: 0.05 ~ 100 × 10-6
09 Antifoaming drilling fluid: high viscosity sulfonate metal salt (calcium petroleum sulfonate: sodium sulfonated asphalt = 1:1), the addition of siloxane amount of about 100 to 400 × 10-6 or 5 to 15 mg / Kg, sulfonate: siloxane close to 1:1 is preferred.
10 lubricants: such as internal combustion engines, automotive lubricants, metal working fluids, compressor oils, etc., when added with silicone oil for defoaming, because of the following advantages:
A. Difficult to dissolve in lubricating oil, in a dispersed state, conducive to adsorption in the bubble film to break the bubble;
B. Alkyl similar to mineral oil, can be squeezed into the bubble film, weakening the molecular gravity;
C. Low surface tension, good penetration, adsorption on the surface of the bubble film so that the local surface tension is reduced, due to uneven surface tension of the bubble film and bubble breaking. Heavy oil selection viscosity of small silicone oil, add 1 ~ 10 × 10-6.
In addition, alkyl polyacrylate is also better, with better gas release. Branched chain amine added to crude gasoline, naphtha, and then added to the lubricating oil, can also be used as an antifoam agent, add the amount of micro 0.05 ~ 1%, this antifoam agent can be added to the metal cutting fluid.
Three paper industry
01 Pulping: silicone emulsion defoamer (90g/T paper).
02 coated paper: coating paint, calendaring after printing pictures and newspapers and other paper, coated bubbles generally use non-silicon defoamer.
03 Sewage treatment: water emulsion type silicone defoamer.
Application in paint and ink
1. Requirements for defoamer in coating production:
(1) It has a certain affinity with the active substances on the surface of the foam, but it should be insoluble and insoluble in the bubbling liquid;
(2) The surface tension is lower than that of the foaming liquid and has a low HLB value;
(3) The emulsion (latex) should be stabilized;
(4) The coating film can not cause fish-eye and shrinkage of the adverse consequences;
(5) Antifoam agent for water-based coatings: more use of insoluble substances in water, such as mineral oil, high-grade alcohols, silicone resin, silicone is the best antifoam agent for water-based coatings. Antifoam agent for non-water-based coatings: commonly used substances insoluble in organic solvents, such as low-grade alcohols, silicone resins (silicone resin dosage should be appropriate, too much easy to shrinkage cracks, traps, and now more modified silicone resins or emulsified silicone resin)
2. Recommended silicone defoamer for water-based coatings
(1) Silicone oil, hydrophobic SiO2 mixture is applicable: epoxy resin, pouring coating, dosage of 0.3%; thermoplastic acrylic resin, spraying, dosage of 0.3%
(2) polyether polysiloxane and hydrophobic SiO2 mixture is applicable: thermosetting alkyd resin, dip coating amount of 0.3%, scraping coating amount of 0.1%
(3) Hydrophobic SiO2, hydrocarbons, silicone oil mixture is applicable: thermoplastic acrylic resin, printing, ink, the amount of 0.1%; air-drying acrylic resin, pouring coating, the amount of 0.5%.
(4) Silicone oil and hydrophobic SiO2 mixture emulsion is suitable for: alkyd-modified phenylpropylene resin, pouring coating, dosage 0.5%.
V Silicone defoamer for detergent industry
Polysiloxane and modified sodium tripolyphosphate as powder detergent additives, containing SiO2 for 2-6% of the dimethyl silicone oil (1500c.s) emulsion and anhydrous sodium tripolyphosphate mixed with the amount of emulsion 10-40%, the formation of hydrates as additives. Metal cleaning fluid, alkali resistance is required, the best when adding liquid products transparent and defoaming activity.
Six food industry silicone defoamer
Polysiloxane resin for food: dimethyl polysiloxane as the main body, containing less than 15% SiO2 food for the aqueous solution, with its emulsified products, others can be used directly with oil-based products, dosage control.
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