Question

What is the main component of Polyoxyethylene Stearate SG-9?

Answer
2026-05-17 官方文档 硬脂酸聚氧乙烯醚SG-9

The main component of Polyoxyethylene Stearate SG-9 is polyoxyethylene (9) stearate, produced by the addition polymerization of stearic acid with 9 moles of ethylene oxide (EO).

Detailed Description

The chemical name of Polyoxyethylene Stearate SG-9 is polyoxyethylene (9) stearate (English name: Polyethylene Glycol Monostearate, 9 EO), CAS number 9004-99-3, which is a nonionic surfactant. Its aliases also include: polyethylene glycol monostearate, PEG-9 stearate, etc.

From a molecular structure perspective, this product is made by using naturally derived or synthetic stearic acid (octadecanoic acid) as the hydrophobic end initiator, undergoing addition polymerization with ethylene oxide (EO) under the action of a catalyst. The "9" indicates that an average of 9 ethylene oxide units are incorporated per molecule, forming the hydrophilic polyoxyethylene chain segment. This structure imparts the typical amphiphilic molecular characteristic of having one lipophilic end and one hydrophilic end.

The product appears as a white to slightly yellow waxy solid with an HLB value of approximately 11~12, possessing good emulsifying, dispersing, wetting, solubilizing, and antistatic properties. As a nonionic surfactant, it remains stable over a wide pH range, has strong hard water resistance, and can be widely used in combination with anionic, cationic, and other nonionic surfactants.

Technical Parameters

ParameterValue
Chemical NamePolyoxyethylene (9) stearate
CAS Number9004-99-3
AliasesPolyethylene glycol monostearate, PEG-9 stearate
Ionic TypeNonionic surfactant
Raw Material CompositionStearic acid + 9 moles of ethylene oxide (EO)
AppearanceWhite to slightly yellow waxy solid
HLB ValueApproximately 11~12
SolubilityDispersible/soluble in water (forming emulsion or micellar solution)

Application Recommendations

Based on the structural characteristics of its main component (lipophilic stearic acid chain + hydrophilic PEG-9 segment), this product is widely used in the following fields:

  • Textile Industry: Used as an emulsifier and antistatic agent in spinning finishes, as well as a component in finishing softeners.
  • Cosmetics and Personal Care: Acts as an O/W emulsifier and solubilizer in creams, lotions, and cleansing products.
  • Metalworking Fluids: Serves as an emulsifier and lubricant in cutting fluids and grinding fluids.
  • Agrochemical Formulations: Used as an emulsifier in emulsifiable concentrates and aqueous emulsions to ensure uniform dispersion of active ingredients.

Precautions

  • This product may cause some irritation to eyes and skin (R36/37/38); it is recommended to wear protective gloves and chemical safety goggles during handling.
  • Store in a cool, dry, well-ventilated warehouse, with temperature preferably not exceeding 35°C, avoiding moisture and direct sunlight.
  • Keep away from incompatible materials such as strong oxidizers and strong acids, and keep containers tightly closed.
  • This product is readily biodegradable (>60%, OECD 301B method), but direct discharge into water bodies should still be avoided.