📋 In This Article
- What Is PEG Oleate?
- Chemistry: How PEG Chain Length Controls HLB and Function
- PEG Oleate Grades Compared: PEG 200 to PEG 1000
- PEG 400 Monooleate - The Most Widely Used Grade
- PEG 600 Monooleate - Higher HLB for Demanding Systems
- PEG Oleate vs Glycerol Monooleate: Key Differences
- Applications Across Industries
- How to Choose the Right PEG Oleate Grade
- Formulation Tips and Compatibility Notes
- Quality Specifications and Sourcing
- FAQ
- Contact Sinolook Chemical
🧪 1. What Is PEG Oleate?
PEG Oleate - more precisely Polyethylene Glycol Monooleate - is a family of non-ionic surfactants formed by the esterification of oleic acid (C18:1) with polyethylene glycol (PEG) of a specified molecular weight. The PEG component is a linear chain of ethylene oxide (–CH₂CH₂O–) repeat units; the number in the grade name (PEG 200, PEG 400, PEG 600…) refers to the approximate average molecular weight of the PEG backbone in g/mol.
The product of this reaction is a molecule with a lipophilic oleate tail on one end and a hydrophilic PEG chain on the other - a classic non-ionic amphiphile. What makes PEG Oleates commercially powerful is that the HLB value, water solubility, and functional behavior can be precisely tuned simply by choosing a different PEG molecular weight. A PEG 200 Monooleate is relatively oil-soluble; a PEG 1000 Monooleate is fully water-soluble and behaves more like a solubilizer than an emulsifier.
💡 Monooleate vs Dioleate
PEG Oleates are sold as either monooleates (one oleate chain per PEG molecule) or dioleates (two oleate chains, one on each terminal hydroxyl of the PEG). Monooleates have a free hydroxyl on one end, giving them higher hydrophilicity and HLB. Dioleates are more lipophilic and behave more like emollients than emulsifiers. Unless otherwise specified, "PEG Oleate" in trade typically refers to the monooleate form.
PEG Oleates should not be confused with polysorbates (Tween series), which are ethoxylated sorbitan oleates with a cyclic ring structure. PEG Monooleates have a simpler linear structure - PEG chain with one oleate ester - and generally deliver different performance characteristics including better lubricity and thermal stability compared to polysorbates.
⚗️ 2. Chemistry: How PEG Chain Length Controls HLB and Function
The core principle is straightforward: as PEG chain length increases, the molecule becomes progressively more water-soluble and moves up the HLB scale. The oleate tail remains constant; only the hydrophilic PEG fraction changes.
🧮 Approximate HLB Calculation for PEG Monooleates
HLB ≈ 20 × (M_PEG / M_total)
Where M_PEG = molecular weight of the PEG chain, M_total = M_PEG + 282 (MW of oleate chain)
PEG 200
HLB ~8
PEG 400
HLB ~11
PEG 600
HLB ~13
PEG 1000
HLB ~16
This tunability is the defining advantage of PEG Oleates over fixed-HLB emulsifiers. A formulator who needs an O/W emulsifier at HLB 11 for a mineral oil system can specify PEG 400 Monooleate directly, rather than blending a low-HLB and high-HLB emulsifier to hit a calculated target - a significant formulation simplification.
2.1 Physical State and Handling
Lower-MW PEG Oleates (PEG 200, PEG 400) are oily liquids at room temperature - easy to pump and meter without heating. Higher-MW grades (PEG 600 and above) transition from viscous liquids to waxy solids as the PEG chain crystallizes. PEG 600 Monooleate is typically a soft paste or semi-solid at 25 °C; PEG 1000 Monooleate is a waxy solid requiring melting above ~35–40 °C. This physical state transition is important for manufacturing process design.
2.2 Thermal and Hydrolytic Stability
PEG Monooleates are ester-linked surfactants. Like all esters, they are susceptible to hydrolysis under strongly acidic or alkaline conditions, releasing free oleic acid and the corresponding PEG alcohol. In neutral to mildly acidic aqueous systems (pH 4–8) at temperatures below 60 °C, hydrolytic stability is good and shelf life of 12–24 months is typical under recommended storage. For high-temperature industrial processes (metalworking fluids, textile processing baths) that operate above 60 °C, thermal stability should be validated at operating conditions before committing to a PEG Oleate.
📊 3. PEG Oleate Grades Compared: PEG 200 to PEG 1000
| Grade | Approx. HLB | Physical State (25 °C) | Water Solubility | Primary Function | Key Industries |
|---|---|---|---|---|---|
| PEG 200 Monooleate | ~8 | Oily liquid | Dispersible | Co-emulsifier, emollient, lubricant | Cosmetics, textile, metalworking |
| PEG 400 Monooleate ★ | ~11 | Viscous liquid | Soluble in warm water | O/W emulsifier, solubilizer, lubricant | Pharma, metalworking, textile, cosmetics |
| PEG 600 Monooleate | ~13 | Soft paste / semi-solid | Readily soluble | O/W emulsifier, detergent co-surfactant | Industrial cleaning, textile, pharma |
| PEG 1000 Monooleate | ~16 | Waxy solid (~38 °C mp) | Fully soluble | Solubilizer, detergent, dispersant | Specialty industrial, pharmaceutical solubilization |
| PEG 400 Dioleate | ~7 | Oily liquid | Dispersible | Emollient, lubricant base, plasticizer | Cosmetics, industrial lubricants |
🔬 4. PEG 400 Monooleate - The Most Widely Used Grade
PEG 400 Monooleate is the industry reference grade - the one most formulators mean when they simply say "PEG Oleate." Its HLB of approximately 11 places it squarely in the O/W emulsifier zone, while its liquid state at room temperature makes it easy to handle and incorporate without heating.
| Property | Value / Description |
|---|---|
| INCI Name | PEG-8 Oleate (cosmetic INCI for PEG 400 monooleate) |
| CAS Number | 9004-96-0 (general PEG monooleate) |
| Approximate HLB | 10.5–11.5 |
| Appearance | Amber viscous liquid |
| Approximate Molecular Weight | ~680 g/mol (PEG 400 + oleate chain) |
| Density (20 °C) | ~1.02–1.04 g/cm³ |
| Solubility | Soluble in warm water, ethanol, acetone; dispersible in mineral oil |
| Acid Value | ≤ 5.0 mg KOH/g |
| Saponification Value | 75–95 mg KOH/g |
| Biodegradability | Readily biodegradable |
4.1 Why HLB ~11 Is Commercially Important
HLB 11 is the optimal O/W emulsification zone for mineral oil (required HLB 10–12) - one of the most widely used oil phases in metalworking fluids, textile lubricants, and industrial emulsions. This means PEG 400 Monooleate can often be used as a single emulsifier without blending, which simplifies formulation and reduces raw material inventory.
It also provides excellent lubricity - the long oleate chain adsorbs on metal surfaces and reduces friction in metalworking and textile processing operations, providing functionality beyond simple emulsification. This dual emulsifier/lubricant role is one reason PEG 400 Monooleate is so widely specified in industrial formulations.
💡 PEG 400 Monooleate vs Polysorbate 80 (Tween 80)
Both are non-ionic O/W emulsifiers in the HLB 11–15 range. PEG 400 Monooleate (HLB ~11) is more lipophilic and offers superior lubricity - making it the preferred choice for metalworking fluids and textile lubricants. Polysorbate 80 (HLB 15) is more water-soluble, better at solubilizing fragrances and hydrophobic actives, and carries USP/NF pharmaceutical monograph status. For pharmaceutical emulsification, Tween 80 is generally specified unless lubricity is needed.
🔬 5. PEG 600 Monooleate - Higher HLB for Demanding Systems
PEG 600 Monooleate (HLB ~13) is chosen when PEG 400 Monooleate does not provide sufficient hydrophilicity for the oil phase being emulsified, or when a more water-soluble emulsifier is needed in a concentrated industrial formulation. It is a soft paste at room temperature, becoming a clear viscous liquid when warmed above ~30–35 °C.
| Property | Value / Description |
|---|---|
| Approximate HLB | 12.5–13.5 |
| Physical State (25 °C) | Soft paste / semi-solid; liquid above ~30–35 °C |
| Approximate MW | ~880 g/mol |
| Solubility | Readily soluble in warm water and alcohols |
| Key Advantage vs PEG 400 | Emulsifies more polar or higher-MW oil phases; better detergency |
When to Choose PEG 600 Over PEG 400
- 🔵 The oil phase requires HLB >12 for effective O/W emulsification (e.g., polyisobutylene, certain esters, aromatic solvents)
- 🔵 The formulation is a concentrated industrial cleaner where better water-dilution stability is needed
- 🔵 The textile processing bath operates at elevated temperature (>50 °C) where the semi-solid state of PEG 600 at room temperature is not a handling concern
- 🔵 You need a higher-HLB emulsifier but want to stay with a single PEG Oleate rather than blending two grades
⚠️ Handling Note for PEG 600 and Higher Grades
PEG 600 Monooleate and higher grades must be stored and metered at temperatures above their softening point. In cold climates or unheated warehouses, the product will solidify in drums - plan for drum warming or heated dosing systems. Always verify the material is fully melted and homogeneous before sampling for CoA comparison or addition to batch.
⚖️ 6. PEG Oleate vs Glycerol Monooleate: Key Differences
Both PEG Oleate and Glycerol Monooleate (GMO) are non-ionic surfactants derived from oleic acid, and both are used across pharma, cosmetics, and food applications - but they occupy opposite ends of the HLB spectrum and serve fundamentally different emulsification roles.
| Property | PEG 400 Monooleate | Glycerol Monooleate (GMO) |
|---|---|---|
| HLB Value | ~11 (O/W range) | ~3–4 (W/O range) |
| Emulsion Type Stabilized | Oil-in-water (O/W) | Water-in-oil (W/O) |
| Hydrophilic Group | Polyethylene glycol chain (–CH₂CH₂O–)ₙ | Glycerol backbone with free hydroxyls |
| Food Approval | Not approved as food additive | E471 (EU); GRAS (USA) |
| Lubricity | Excellent - strong film on metal surfaces | Good - used in food-grade and cosmetic lubrication |
| Primary Industrial Use | Metalworking fluid, textile lubricant, pharma solubilizer | Food emulsifier, cosmetic W/O cream, pharma ointment |
| "Clean / Natural" Status | Generally not accepted in natural cosmetics | Accepted in many natural certification schemes |
| Co-emulsifier Strategy | Can be combined with GMO to fine-tune HLB | Combine with PEG Oleate for complex emulsion systems |
💡 Using GMO and PEG Oleate Together
In complex emulsion systems - for example a pharmaceutical cream or a concentrated metalworking fluid - combining GMO (HLB ~3–4) with PEG 400 Monooleate (HLB ~11) creates a blended emulsifier system with tunable HLB. At a 50/50 blend, the effective HLB is approximately 7 - useful for self-emulsifying systems and microemulsions. The GMO provides interfacial viscosity and W/O tendency; the PEG Oleate provides dispersibility and lubricity. Together they produce a more robust interfacial film than either alone.
🏭 7. Applications Across Industries
🔩 Metalworking Fluids
Primary grade: PEG 400 Monooleate
- Emulsifier in soluble cutting oil concentrates (3–10% in concentrate)
- Lubricant additive reducing tool wear and improving surface finish
- Corrosion inhibitor auxiliary - oleate chain provides passivation on iron and steel
- Rust-preventive oil formulation component
- Compatible with amine-based corrosion inhibitors and biocides
🧵 Textile Processing
Primary grades: PEG 200, PEG 400 Monooleate
- Fiber spin finish lubricant (synthetic fiber extrusion)
- Yarn lubricant in weaving and knitting processes
- Emulsifier in textile finishing baths
- Softening agent for synthetic and blended fabrics
- Scouring auxiliary to remove sizing and spinning oil
💊 Pharmaceuticals
Primary grade: PEG 400 Monooleate
- Solubilizer for poorly water-soluble APIs in oral and topical formulations
- Co-emulsifier in O/W creams and lotions (alongside polysorbates)
- Excipient in soft gelatin capsule fill formulations
- Penetration enhancer in topical semi-solid dosage forms
✨ Cosmetics & Personal Care
Primary grades: PEG 200, PEG 400 Monooleate
- O/W emulsifier and emollient in body lotions and creams
- Solubilizer for fragrance oils and essential oils in water-based products
- Conditioning agent in hair care formulations
- Skin-feel modifier in lightweight facial moisturizers
🌾 Agriculture
Primary grade: PEG 400 Monooleate
- Emulsifier in oil-based pesticide emulsifiable concentrates (EC)
- Spreading and wetting adjuvant in foliar spray formulations
- Co-formulation surfactant with amine salts of herbicides
🏗️ Industrial & Specialty
Grades: PEG 400, PEG 600 Monooleate
- Mold release agent emulsifier in rubber and plastics processing
- Plasticizer in PVC and polymer formulations
- Leather fat-liquoring and finishing agent
- Paper processing and coating auxiliary
🎯 8. How to Choose the Right PEG Oleate Grade
Start with your target HLB and your process temperature capability:
🧪 9. Formulation Tips and Compatibility Notes
9.1 Typical Metalworking Fluid Concentrate (Soluble Cutting Oil)
| Ingredient | % in Concentrate | Function |
|---|---|---|
| Mineral oil (paraffinic, ISO 32) | 40–60% | Base lubricant, heat dissipation |
| PEG 400 Monooleate | 5–10% | Primary emulsifier + boundary lubricant |
| Tall oil fatty acid or oleic acid | 2–5% | Co-emulsifier, extreme-pressure additive precursor |
| Triethanolamine (TEA) or MEA | 2–4% | Neutralizer, corrosion inhibitor, pH buffer |
| Biocide (e.g., MBT, triazine) | 0.1–0.3% | Microbiological control |
| Water | q.s. to 100% | Diluent (concentrate diluted 1:20–1:50 at point of use) |
9.2 Key Compatibility Notes
✅ Compatible with:
Anionic and non-ionic surfactants; amine corrosion inhibitors (TEA, DMEA, DEAE); mineral and synthetic base oils; fatty acids and their salts; most water-soluble solvents (glycols, alcohols); standard metalworking biocides.
⚠️ Caution with:
Strong oxidizing agents (cause ester degradation); high-alkalinity systems (pH >10 causes hydrolysis over time); cationic surfactants at high concentrations (phase separation possible); strong electrolytes at high concentration (salting-out of the PEG chain).
🚫 Avoid:
Prolonged exposure to temperatures above 80 °C in aqueous solution (accelerates hydrolysis); storage in contact with iron or copper without antioxidant (catalyzes oleate oxidation); freezing followed by rapid thawing without remixing (can cause phase stratification in lower-grade material).
📊 10. Quality Specifications and Sourcing
| Parameter | PEG 200 Monooleate | PEG 400 Monooleate | PEG 600 Monooleate | Significance |
|---|---|---|---|---|
| Acid Value (mg KOH/g) | ≤ 5 | ≤ 5 | ≤ 5 | Free oleic acid content; freshness indicator |
| Saponification Value (mg KOH/g) | 110–135 | 75–95 | 55–75 | Ester content; identity confirmation |
| Hydroxyl Value (mg KOH/g) | 100–140 | 55–80 | 35–60 | Indicates mono vs diester ratio |
| Water Content (KF, %) | ≤ 1.0 | ≤ 1.0 | ≤ 1.0 | Prevents hydrolysis during storage |
| Colour (Gardner or APHA) | ≤ 6 Gardner | ≤ 6 Gardner | ≤ 5 Gardner | Important for cosmetic and light-coloured formulations |
| Heavy Metals (ppm) | ≤ 10 | ≤ 10 | ≤ 10 | Required for pharma and skin-contact applications |
✅ Supplier Checklist for PEG Oleates
- ✅ Batch-specific CoA with acid value, saponification value, hydroxyl value, and water content?
- ✅ PEG backbone MW confirmed (GPC or viscosity method) - grade specification is meaningless without this
- ✅ Feedstock origin - oleic acid source (vegetable vs synthetic) and PEG grade declared?
- ✅ REACH registration for EU supply?
- ✅ ISO 9001 quality management system in place?
- ✅ Packaging options: drums (180 kg), IBC (1,000 kg) - heated IBC for PEG 600+?
- ✅ Samples available (1–5 kg) for incoming QC and formulation trials?
❓ 11. Frequently Asked Questions
📦 Source PEG Oleate from Sinolook Chemical
Sinolook Chemical supplies PEG Monooleate in PEG 200, PEG 400, and PEG 600 grades for industrial, cosmetic, and pharmaceutical applications - with full documentation including batch CoA, MSDS, REACH registration, and HS code declarations for every shipment. Minimum order 200 kg; samples available for formulation trials.
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www.sinolookchem.com🔗 Related Products: PEG Oleate Product Page · SPAN 80 · Cocamide DEA · Oleate Esters Category
