Emulsifiers & Demulsifiers

Browse CheMost Emulsifiers & Demulsifiers

Start with the product family that best matches your formulation target. Each product page goes deeper into the exact grade, properties, and documentation.

Polyisobutylene Succinic Anhydride (PIBSA)

Chlorine-free polyisobutylene succinic anhydride (PIBSA) — a highly active, ashless emulsifier for metalworking fluids (good emulsification, hard-water resistance, low foam) and the classic precursor to PIB succinimide dispersants.

Amine Polyether Demulsifier

Oil-soluble amine-polyether demulsifier — an amine-and-propylene-oxide additive that breaks oil-water emulsions and speeds water separation in lubricating oils that come into contact with water, with a trace of nitrogen for added antioxidancy and synergy with succinic-acid rust inhibitors.

Polyether Demulsifier

Oil-soluble non-ionic polyether (EO/PO) demulsifier — enhances oil-water separation at very low treat and also helps suppress foaming, particularly suited to marine and industrial lubricating oils exposed to water.

Two Opposite Jobs in One Additive Family

Emulsifiers and demulsifiers are both interfacial (surface-active) tools, but they pull in opposite directions — so the very first thing to settle is which one your fluid needs:

• Demulsifier → break the emulsion. It promotes oil/water separation so water that gets in (condensation, steam, coolant leaks) drops out fast and can be drained. STLE defines a demulsifier simply as “an additive that promotes oil/water separation in lubricants that are exposed to water or steam.” This is what turbine, hydraulic, gear and circulating oils need.
• Emulsifier → stabilise the emulsion. It does the reverse — it keeps oil and water mixed as a fine, stable emulsion that does not separate on standing. This is what soluble (emulsifiable) and semisynthetic metalworking fluids need, where the working fluid is deliberately an oil-in-water emulsion.

They are not a “better/worse” pair — they are opposite goals. An additive that is excellent at one is, by definition, wrong for the other, so selection starts with the application, not the product.

Why Water Separation (Demulsibility) Matters

Water finds its way into almost every industrial oil. It shows up three ways — dissolved, emulsified and free — and the last two are the damaging ones. Emulsified and free water lower the effective viscosity and load-carrying film, form sludge and deposits, and accelerate oxidation, wear and rust and corrosion. The catch is that many polar additives (detergents, some rust inhibitors and EP agents) raise the oil’s tendency to hold water, which works against demulsibility. Good water-shedding is therefore a property that has to be designed into the oil — partly through additive choice and partly with a demulsifier.

Demulsibility is read with standard methods: ASTM D1401 (water separability of petroleum oils and synthetic fluids — it reports the oil/water/emulsion volumes and the time to separate, e.g. 40-37-3 in 15 minutes) and ASTM D2711 (demulsibility characteristics for higher-additive and EP-type oils). A finished oil is validated against these, not assumed.

Choosing an Emulsifier — The HLB Idea

On the emulsifier side, selection is governed by HLB (hydrophilic-lipophilic balance) — a number for how water-loving versus oil-loving a surfactant is. As a rule of thumb, an HLB of roughly 3–6 favours a water-in-oil emulsion, while 8–18 favours oil-in-water. Most practical emulsifier systems blend a low-HLB and a high-HLB surfactant to hit the target for the base oil being emulsified. In metalworking, sodium petroleum sulfonates are the classic primary emulsifier for soluble cutting oils. Emulsion stability is never down to the emulsifier alone — it also depends on the base oil and the water hardness it will be mixed with.

The CheMost Range — How to Choose

CheMost covers both directions. Start with the job — build a stable emulsion, or break one:

Emulsifiers — build & stabilise emulsions (soluble oils & MWF)

Demulsifiers — break emulsions & shed water (turbine, hydraulic, circulating oils)

Treat Rate & Formulation Reality

The two directions sit at opposite ends of the dosing scale:

• Demulsifiers are low-treat, high-impact. They are used at small additions and must stay soluble or stably dispersible in the oil over its life. Published fuel-additive data shows demulsifiers used at only ~1–200 ppm — useful as an order-of-magnitude, but it is fuel data and should not be read as a universal lubricant treat rate.
• Emulsifiers are a major component. In a soluble-oil or semisynthetic concentrate the emulsifier package is one of the largest ingredients, not a trace additive, because it has to carry the whole oil phase into a stable emulsion when diluted with water of variable hardness.

Exact dose and combinations depend on your base oil, the rest of the package, your water quality and the demulsibility or emulsion-stability target. CheMost can advise on grade and starting point on request.

Common Applications

• Turbine & circulating oils: fast water shedding (ASTM D1401) so condensate and steam leakage drain off and do not emulsify or form sludge — a demulsifier job.
• Hydraulic fluids: water separation to protect the film and prevent rust and valve problems — a demulsifier job.
• Industrial gear & compressor oils: demulsibility under water and steam exposure.
• Soluble (emulsifiable) cutting oils: a stable, fine oil-in-water emulsion at the point of use — an emulsifier job.
• Semisynthetic metalworking fluids: emulsion stability across the working dilution and varying water hardness — an emulsifier job, paired with foam control.

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