The material selection platform
Cosmetics Ingredients
The material selection platform
Cosmetics Ingredients


CAS Number 9003-27-4
Chem/IUPAC Name: Homopolymer of 2-methyl-1 propene
COSING REF No: 79008
Polyisobutene is a polymer derived from isobutene, a gaseous hydrocarbon, and appears as a clear, colorless to pale yellow, viscous liquid with a thick consistency. It is primarily utilized as an emollient in cosmetics, providing moisturizing and protective properties to the skin. It forms a thin, occlusive film on the skin's surface, preventing water loss and maintaining skin hydration. Polyisobutene is commonly found in various cosmetic products such as lip balms, moisturizers, foundations, and lipsticks, adding moisturization and texture-enhancing benefits. The high molecular weight of this ingredient contributes to its thick texture and non-greasy feel. The chemical formula of Polyisobutene is (C4H8)n, where "n" represents the repeating units in the polymer chain.

What is POLYISOBUTENE used for?

Polyisobutene is an effective ingredient that finds many uses in the cosmetic and skin care industry.
  • Skin care: It serves as an emollient and moisturizer. It forms a protective barrier on the skin's surface, preventing transepidermal water loss and helping to retain moisture. This makes Polyisobutene a valuable ingredient in body lotions and moisturizers, providing long-lasting hydration and smoothness to the skin
  • Cosmetic products: It is utilized for its film-forming properties. It imparts a smooth and silky texture to products, allowing for easy application and enhancing their overall performance. In lipsticks and lip glosses, it helps to create a long-lasting, non-sticky, and shiny finish


Polyisobutene is typically produced through the polymerization of isobutene monomers. The polymerization reaction involves combining isobutene in the presence of a catalyst, such as aluminum chloride or boron trifluoride.

What does POLYISOBUTENE do in a formulation?

  • Emollient
  • Film forming
  • Moisturising

Safety profile

Polyisobutene is generally regarded as safe for cosmetic use, posing minimal risk of skin irritations or allergies. It is non-comedogenic, meaning it does not clog pores or promote acne formation. Moreover, Polyisobutene is derived from petroleum or plant-based sources, making it suitable for vegan-friendly cosmetic formulations.

Technical profile

Property Values
Boiling Point 300°C
Melting Point 54-56°C
Solubility Insoluble in water
Viscosity High
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