PEG-75 Stearate is a chemical compound, an ester derived from polyethylene glycol (PEG) and stearic acid. 

The name describes the structure of the molecule:

• PEG-75 refers to a specific type of polyethylene glycol with an average molecular weight of around 75 ethylene oxide monomer units. This makes it water-soluble and effective as a solubilizer in various formulations.
• Stearate comes from stearic acid, a common fatty acid. Stearates are used for their emulsifying properties, helping to stabilize and maintain the mixture of oily and watery ingredients in emulsions.

Chemical Industrial Synthesis Process

• Preparation of ingredients. Stearin, a pure form of stearic acid, is prepared, and PEG-75, a polymer of ethylene oxide with an average molecular weight, is synthesized or procured.
• Esterification reaction. Stearic acid and PEG-75 are combined in a reactor under controlled temperature and pressure conditions. Catalysts are added to facilitate the formation of the ester.
• Monitoring the reaction. The reaction is monitored to ensure it proceeds correctly and to determine the completion point when the reactants have fully reacted.
• Purification. The crude product is purified through techniques such as vacuum distillation or filtration to remove impurities and reaction residues.
• Quality control. Samples of the final product are tested for compliance with quality specifications, including tests for purity, viscosity, and chemical stability.

What it is used for and where

This ingredient is particularly effective at maintaining the stability of emulsions, preventing the separation of oily and watery ingredients in products such as creams and lotions. It also offers benefits in product texture, making it smoother and easier to apply. PEG-75 Stearate is well-tolerated by the skin and can help form a light film on the skin that helps retain moisture without being heavy or leaving a greasy feel.

Cosmetics - INCI Functions

• Surfactant - Cleansing agent. Cosmetic products used to cleanse the skin utilise the surface-active action that produces a lowering of the surface tension of the stratum corneum, facilitating the removal of dirt and impurities. 

CAS   9004-99-3

Main uses of PEG-75 Stearate.

Emulsion Stabilization. It contributes to the stability of emulsions, preventing the separation of oil and water components in cosmetic products, such as creams and lotions.

Product Texture Improvement. It helps make the texture of products more uniform and smooth, thereby enhancing the sensory experience during use.

Moisturizing Effect. Although its primary role is not moisturization, the formation of a stable emulsion structure can help retain moisture in the skin.

Skin Compatibility. Generally well tolerated by the skin, PEG-75 Stearate is suitable for use in formulations intended for sensitive skin.

Versatile Application. It can be employed in a wide range of skincare and haircare products, including serums, creams, lotions, and conditioners.

Ease of Formulation. This emulsifier is compatible with many other cosmetic ingredients, facilitating the formulation of complex products.

Safety

It is an ethoxylated product, but since 75 ethylene oxide units are not easily absorbed through the stratum corneum, it seems unlikely that skin penetration would cause damage.