Polydimethylsiloxane Lotion
Polydimethylsiloxane lotion is the aqueous emulsion form of dimethylpolysiloxane, a linear silicone polymer of repeating dimethylsiloxane units terminated with trimethylsilyl groups. The lotion is not a new chemical but a delivery form: the silicone fluid, usually blended with a small amount of hydrophobic silica, is emulsified in water with non-ionic emulsifiers to give a pourable white liquid that can be dosed into aqueous process streams.
Its function is defoaming. The silicone has very low surface tension and is insoluble in the foaming medium, so droplets spread rapidly across the gas and liquid interface, thin the film between the bubbles and rupture it, while the silica particles pierce the film mechanically. Very low addition rates are effective, and the polymer is chemically inert, thermally stable and unaffected by pH across the normal processing range.
The emulsion runs at around 10 to 30 percent active silicone, a white to off-white liquid with a slight characteristic odour. It dilutes readily in water for dosing, but it is shear sensitive and breaks on freezing, so it is stored above freezing and stirred gently rather than pumped through high shear equipment. The neat silicone fluid itself is insoluble in water and in ethanol and soluble in hydrocarbon solvents.
We source bulk Polydimethylsiloxane Lotion from top China manufacturers for our partners. The manufacturer is in Guangxi. A smaller requirement can ship in a combined container with other ingredients.
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- Function
- Emulsifier
Specifications
| Item | Specification |
|---|---|
| Appearance | White to off-white pourable emulsion |
| Odour | Slight, characteristic |
| Active dimethylpolysiloxane | 20.0 - 30.0% |
| Identification | Infrared spectrum of extracted silicone conforms |
| Viscosity of base fluid (25 °C) | Within declared range |
| Emulsion viscosity (25 °C) | 500 - 3,000 mPa·s |
| pH (as supplied) | 4.0 - 8.0 |
| Density (25 °C) | 0.98 - 1.02 g/mL |
| Dilution stability | No separation after 1:20 dilution in water |
| Heavy metals (as Pb) | ≤ 5 mg/kg |
| Lead | ≤ 1 mg/kg |
| Arsenic | ≤ 1 mg/kg |
| Total plate count | ≤ 1,000 cfu/g |
| Salmonella | Absent in 25 g |
Common Markets Grades
The main variables are active silicone content and emulsifier system. Food grade emulsions are usually offered at 10, 20 or 30 percent active dimethylpolysiloxane, and the higher concentrations are diluted on site before dosing. The neat fluid is separately traded by viscosity, typically 100 to 60,000 centistokes, with the higher viscosity fluids giving more persistent foam control and the lower ones a faster initial collapse of the foam.
Beyond that, self-emulsifying compounds, silica filled antifoam compounds without water and powdered antifoams on a carrier are made for applications where an aqueous emulsion is unsuitable. Food grade material is distinguished from industrial grade by the purity of the emulsifiers and preservatives used and by compliance with the additive specifications for dimethylpolysiloxane, since the silicone itself is chemically the same in both.
Applications
- Frying oils, where it suppresses foaming and slows oxidative breakdown of the oil in continuous fryers
- Sugar refining and syrup evaporation, where boiling juice foams heavily and carries over into vapour lines
- Fermentation broths in yeast, amino acid and enzyme production, where aeration generates persistent protein foam
- Fruit and vegetable juice processing, where foam limits tank fill and interferes with filling accuracy
- Soy protein, starch and gluten processing, where washing and separation steps foam under agitation
- Brewing and distilling, where foam control protects fermenter headspace and heat exchanger performance
- Jam, sauce and soup cooking, where entrained air reduces vessel capacity and disturbs heat transfer
- Bottle and can filling lines, where foam collapse decides line speed and fill weight consistency
- Clean in place systems, where detergent foam interferes with pump operation and rinse verification
China Manufacturers of Polydimethylsiloxane Lotion
Top Polydimethylsiloxane Lotion manufacturers in China.
Company names and logos are the property of the manufacturers themselves. They are listed here because our own directory records them as producing this ingredient. A listing is not an endorsement by them, and we do not represent them or speak on their behalf.
Regulatory Status
In the United States 21 CFR 173.340 permits dimethylpolysiloxane as a defoaming agent in food, sets out the conditions of use and the maximum residual level in the finished food, and also clears it as a component of certain food contact materials. The emulsifiers, thickeners and preservatives used to build the emulsion must each be separately permitted for the intended use.
In the European Union Regulation (EC) No 1333/2008 authorises dimethyl polysiloxane as E 900, an anti-foaming agent, with the food categories and maximum levels set in the annexes, and identity and purity criteria including a viscosity range and limits on residual low molecular weight siloxanes given in the specifications regulation. JECFA has evaluated dimethylpolysiloxane and published specifications for it, and it appears in the Codex General Standard for Food Additives in the antifoaming function.
Manufacturing Process
The silicone fluid is made first. Dimethyldichlorosilane is hydrolysed with water to give a mixture of linear and cyclic siloxanes, and the cyclic material is separated and then ring opened and polymerised over an acid or base catalyst with a defined amount of end blocker, which fixes the chain length and therefore the viscosity. The polymer is neutralised and stripped under vacuum to remove residual low molecular weight cyclic siloxanes, giving a clear, odourless fluid of controlled viscosity.
To make the lotion, the fluid is compounded with hydrophobic fumed silica under high shear and heat so the silica disperses evenly and becomes anchored in the silicone. That antifoam compound is then emulsified into water containing non-ionic emulsifiers, a thickener and a preservative, first with a high shear mixer and then through a homogeniser or colloid mill to bring the droplet size into the range that gives storage stability. The finished emulsion is checked for active content, particle size, viscosity and pH, filtered and filled into drums or intermediate bulk containers.
