Isobutylene/Styrene Copolymer

AKA “Butyl Styrene Copolymer”

Synthetic

Ingredient Facts

Isobutylene/styrene copolymer

AKA: Butyl Styrene Copolymer

Synthetic · Emollient · EWG: 4

Synthetic

Emollient

Occlusive

Skin Conditioner

Synthetic

Clean

A lightweight film-forming ingredient that helps products glide smoothly onto skin and hair while creating a flexible, breathable finish that lasts throughout the day.

CAS #

9011-12-5

Form

Liquid

State

Solid

See origin →

Functions

Film Forming

Creates a physical seal on skin to lock moisture in and keep irritants out. The "slugging" ingredient — barrier protection.

Viscosity Controlling

Emollient

Fills in the tiny cracks between skin cells to make everything feel smooth and soft. The "silky finish" ingredient.

Smoothing

Polymer With 2 Methyl 1 Propene

Traditional Use

Synthetic polymer created as a cosmetic ingredient in the 20th century. Formulated to provide film-forming and texture-enhancing properties in skincare, sunscreens, and color cosmetic products.