What it is
This is a thermoplastic elastomer copolymerized from butylene, ethylene, and styrene units. It is oil-soluble and is used to gel and thicken oil phases, giving body and a cushiony texture to anhydrous formulas such as lip products and sticks. It also contributes film-forming properties that help deposit a smooth, cohesive layer.
Safety & warnings
Inert hydrocarbon copolymers of this class are generally well tolerated and are not recognized as common allergens or sensitizers.
Origin & sourcing
Synthetic; a hydrocarbon copolymer.
Questions everyone asks
What does this copolymer do in a lip product?
It gels and thickens the oil phase and forms a smooth film, giving the product body and a cushiony, cohesive texture.
Is it water-soluble?
No, it is oil-soluble and is used to structure anhydrous, oil-based formulas.