Isobutylene/Styrene Copolymer
AKA “Butyl Styrene Copolymer
Synthetic
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Ingredient Facts
Isobutylene/styrene copolymer
AKA: Butyl Styrene Copolymer
Synthetic · Film Forming | Viscosity Controlling | Skin Conditioning - Emollient | Smoothing · EWG: 4
Plant-Derived
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
Plant-Derived
Synthetic
Function
Film Forming | Viscosity Controlling | Skin Conditioning - Emollient | Smoothing
Benefits
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.
Skin Types
all-skin-types
Best For
Target
General
Melanin-Rich Skin
Suitable
Pregnancy Safe
Yes
EWG Score4
CIR Safety Findings
medical-approval, all-shades-safe
Regulatory Status
USApermitted
EUrestricted
JAPANrestricted
CANADArestricted
Verified Feb 2026
Data: CosIng · EWG · CIR