Technical Specifications
| Property | Unit | Typical Value | Test Method |
|---|---|---|---|
| Appearance | Colorless clear liquid | Visual | |
| Density at 25 °C | kg/m³ | 940–980 | ASTM D4052 |
| Viscosity at 25 °C | mm²/s | 20–1000 | ASTM D445 |
| Flash Point | °C | 330 | ASTM D93 |
| Recommended addition | ppm | 10–500 | — |
* Typical values from batch production. Batch-specific COA available on request.
Technical content reviewed by the CheMost additives team · Specifications last reviewed
Molecular Structure
Molecular structure · polydimethylsiloxane defoamer
Polydimethylsiloxane (PDMS) — linear —[Si(CH₃)₂–O]ₙ— dimethyl-silicone fluid
A linear dimethyl-silicone (PDMS) fluid: very low surface tension lets it enter and rupture surface-foam films at ppm dosing.
What Is a Polydimethylsiloxane (PDMS) Silicone Defoamer?
CheMost-G1000 is a polydimethylsiloxane (PDMS) silicone fluid used as a defoamer (foam inhibitor) for oils and industrial fluids. It is a colorless, clear, non-toxic liquid with a very low surface tension and a high flash point (330 °C), and it suppresses surface foam at parts-per-million dosing.
Foam is a problem in gear oils, hydraulic fluids, industrial and process oils because it causes pump cavitation, noisy and spongy operation, pressure spikes, faster oxidation and poor lubrication. A silicone defoamer works because PDMS is largely incompatible with the oil and has a lower surface tension than it: the fine silicone droplets enter and spread across the foam-bubble film, destabilise it and make the bubble rupture. Of all defoamer chemistries, silicone gives the highest raw efficiency against surface (macro) foam.
That same incompatibility has to be controlled. The data sheet calls for additional dilution after filling, to avoid turbidity — the fluid must be finely and evenly dispersed, and over-dosing causes haze and can reduce air-release performance. G1000 is supplied in a range of viscosity grades (20, 50, 100, 350, 500 and 1000 mm²/s at 25 °C) so the grade can be matched to the system.
How a Silicone Defoamer Works
Very low surface tension
PDMS has a lower surface tension than the oil, so it readily enters and spreads across the surface of a foam bubble’s liquid film.
Controlled incompatibility
Being only slightly soluble, the silicone forms fine droplets that migrate to the foam lamella and displace the surfactants stabilising it — the film thins and the bubble breaks.
ppm-level, high-impact
Because the mechanism is interfacial, a tiny amount does the work: foam control is achieved at 10–500 ppm, with ≥10 ppm generally recommended.
Pre-dilute for even dispersion
The fluid is diluted before use so it disperses finely and evenly; an excess or a poor dispersion causes turbidity and can hurt air release, so dosing is kept to the minimum that controls foam.
Silicone vs Acrylate Compound Defoamers — Where G1000 Fits
CheMost offers both defoamer routes. The table places the silicone G1000 against the acrylate-based compound defoamer so you can pick by the job at hand — raw surface-foam knockdown versus a gentler effect on air release. All figures are from each grade’s data sheet.
| Grade | Chemistry | Dose | Best for |
|---|---|---|---|
| G1000 (this page) | Polydimethylsiloxane (silicone) | 10–500 ppm (pre-dilute) | Maximum surface-foam knockdown; broad industrial/process use |
| Compound defoamer (T9100/T9200) | Acrylate + trace silicone | 30–200 ppm (no dilution) | Foam control with low impact on air release; sulfonate-containing oils (T9200) |
| Silicone-free defoamer (T9000) | Non-silicone organic polymers | 20–200 ppm (no dilution) | Systems where any silicone is unacceptable; air release unaffected |
Choose G1000 when you need the strongest macrofoam efficiency and can manage the dilution and air-release trade-off; choose the acrylate compound defoamer when air release and an easy, no-dilution add matter more than raw knockdown.
Applications
CheMost-G1000 is used as the silicone defoamer in formulations targeting the duties below:
Industrial & circulating oils
Foam control in industrial, circulating and process oils where surface foam must be knocked down quickly.
Hydraulic & gear oils
Suppression of surface foam in hydraulic and gear oils; dose to the minimum that controls foam to protect air release.
Compressor & turbine oils
Defoaming in compressor and turbine oils, with the viscosity grade matched to the base fluid.
Metalworking fluids
Foam control in oil-based metalworking fluids and a range of other process fluids.
Finished-oil performance approvals belong to the fully formulated oil, not to an individual additive component.
Treat Rate
The data sheet gives an application window rather than a fixed dose, so the guidance below is indicative — confirm the final level against a foam bench test (ASTM D892).
First-order estimate. Silicone defoamers are very-low-treat, high-impact: the application range is 10–500 ppm, with ≥10 ppm generally recommended. A small amount controls the foam; over-dosing causes turbidity and can reduce air release, so the target is the lowest level that meets the ASTM D892 foam result.
Pre-dilute the fluid before adding it so it disperses finely and evenly. The exact dose depends on the base oil, the surface-active additives present and whether entrained air (air release) also has to be managed — in air-release-sensitive systems an acrylate compound defoamer may be the better route.
Treat rates are indicative, not fixed dosages. CheMost can provide formulation and treat-rate support on request.
Formulating With G1000 — Complementary Additives
Acrylate compound defoamer
Where air release and compatibility matter more than raw knockdown, the acrylate-based compound defoamer is the alternative route — gentler on surface tension and added without dilution.
Detergents
Surface-active detergents and other surfactants stabilise foam; the defoamer is dosed to overcome them, so the foam-stabilising load of the package guides the level.
Industrial & hydraulic DI packages
G1000 is the foam-control component alongside the antiwear, rust and oxidation additives of an industrial or hydraulic oil package.
Base oil selection
The viscosity grade (20–1000 mm²/s) is matched to the base fluid for fine, stable dispersion; choosing the right grade is part of avoiding turbidity.
Documentation, Qualification & Regulatory Support
Standard documentation — Certificate of Analysis (COA, per shipment), Technical Data Sheet (TDS) and Safety Data Sheet (SDS, GHS/CLP) — is provided. The full TDS is available on request rather than as a public download. Additional support is available on request:
Regulatory documentation
REACH, TSCA and country-specific market-registration documentation support available on request.
Third-party inspection
SGS / Intertek / BV pre-shipment inspection can be arranged on request.
Custom grades & packaging
Custom viscosity grades and packaging on request.
Formulation support
Defoamer-selection and treat-rate guidance from our technical team.
Packaging & Supply
CheMost-G1000 is stocked and shipped worldwide, with a typical lead time of 1–15 days and a 36-month shelf life at ambient temperature. Samples and quotations are answered within 12 hours.
Packaging
25 kg drum · 200 kg drum.
Minimum order
By drum — contact us for your quantity.
Incoterms
FOB · CIF · EXW, to suit your freight arrangement.
Loading ports
All major Chinese ports.
Frequently Asked Questions
What is a silicone (PDMS) defoamer?
It is a polydimethylsiloxane silicone fluid that suppresses foam in oils and industrial fluids. Its very low surface tension and controlled incompatibility let it enter and rupture surface-foam films at parts-per-million dosing. Silicone gives the highest raw efficiency against surface (macro) foam of the common defoamer chemistries.
Why does it need to be diluted before use?
The data sheet calls for additional dilution after filling to avoid turbidity. A silicone defoamer must be dispersed finely and evenly in the oil; if it is added neat or over-dosed it can cause haze and reduce air release. Pre-diluting into a carrier gives a fine, stable dispersion and lets you meter it accurately at ppm levels.
Silicone or acrylate compound defoamer — which should I use?
Use the silicone (G1000) when you need the strongest surface-foam knockdown and can manage the dilution and air-release trade-off. Use the acrylate compound defoamer when air release and an easy, no-dilution addition matter more — it is gentler on the fluid’s surface tension.
What treat rate should I use?
The application range is 10–500 ppm, with ≥10 ppm generally recommended. Dose to the lowest level that meets your ASTM D892 foam target; over-dosing causes turbidity and can hurt air release. The exact level depends on the oil and the surface-active additives present.
How is it supplied, and how fast can I get a sample?
It is supplied as a colorless clear liquid in 25 kg and 200 kg drums, in viscosity grades from 20 to 1000 mm²/s, with a 36-month shelf life. As a manufacturer and sourcing partner (Est. 2013), CheMost answers sample and quotation requests within 12 hours.