Acrylates C10-30 Alkyl Acrylate Crosspolymer
Also known as Acrylates/C10-30 alkyl acrylate crosspolymer, Carbomer copolymer, Carbopol 1342, Carbopol 1382, Pemulen TR-1, Pemulen TR-2, Carbopol Ultrez 20, Carbopol Ultrez 21
“CIR Expert Panel says: safe as used in cosmetics.”
Acrylates/C10-30 Alkyl Acrylate Crosspolymer is a high-molecular-weight crosslinked copolymer of acrylic acid and C10-C30 alkyl acrylate esters, marketed most commonly under trade names Carbopol 1342, Carbopol 1382, Pemulen TR-1, Pemulen TR-2, and Carbopol Ultrez 20/21 (all Lubrizol). In cosmetic formulations it functions as a rheology modifier and primary emulsion stabilizer for water-in-oil and oil-in-water systems — the C10-30 alkyl groups provide hydrophobic anchoring that stabilizes the oil phase while the acrylic acid backbone, neutralized to its sodium or triethanolamine salt, swells into a high-viscosity hydrogel network. Pemulen grades in particular enable oil phase loadings up to ~20% in cold-process formulations without conventional surfactants. The Cosmetic Ingredient Review Expert Panel assessed 23 crosslinked alkyl acrylates including Acrylates/C10-30 Alkyl Acrylate Crosspolymer in a 2017 Safety Assessment (Fiume, Heldreth, Boyer, Bergfeld, Belsito et al., Int J Toxicol 36(Suppl.2):59S-88S, PMID 29025328). The Panel's conclusion is a split finding: crosslinked alkyl acrylates are safe in the present practices of use and concentration when NOT polymerized in benzene, while data do not support the safety of grades polymerized in benzene. The distinction reflects a manufacturing-process concern rather than an intrinsic chemistry concern: legacy grades such as Carbopol 1342 historically used benzene as the polymerization solvent and retained up to ~0.5% residual benzene (IARC Group 1 human carcinogen) in the finished polymer powder; modern grades polymerized in cyclohexane or ethyl acetate do not carry this residual. The QRT p. 3 row encodes this conclusion as 'SQ/UNS' with the split Detail text 'safe in the present practices of use and concentration when polymerized in benzene | data does not support use when polymerized in benzene' — the first clause is the SQ (Safe Qualified) determination and is a standard CIR phrasing that means 'safe except when polymerized in benzene'; the second clause is the UNS (Unsupported) determination for benzene-polymerized grades. Polymerization in benzene is a formulator/raw-material procurement concern: specifying non-benzene-polymerized grades (modern Pemulen / Carbopol Ultrez series and any Carbopol grade manufactured after Lubrizol's switch to ethyl acetate solvent) satisfies the SQ branch of the CIR finding. Acrylates/C10-30 Alkyl Acrylate Crosspolymer is used across leave-on and rinse-off cosmetic categories; CIR reported the highest use concentrations at 1.1% in rinse-off and 0.4% in leave-on for benzene-polymerized grades — both below the 1-2% typical use range for modern non-benzene grades. Clinical dermal studies cited in the 2017 assessment showed no primary irritation or sensitization at typical use concentrations; the polymer is too large to penetrate intact skin. Monomer residuals (acrylic acid, C10-30 alkyl acrylates) are controlled by manufacturing specifications and are negligible in finished polymer.
Primary emulsion stabilizer for surfactant-free and cold-process oil-in-water emulsions — Pemulen TR-1 and TR-2 enable oil-phase loadings up to ~20% without conventional surfactants, a key tool for clean-beauty and sensitive-skin formulations
Rheology modifier that builds viscosity and yield stress at low use concentrations (typically 0.1-1.0%), delivering the 'gel cream' texture characteristic of many modern serums and lightweight moisturizers
Electrolyte-tolerant relative to simple carbomers — the C10-30 alkyl acrylate comonomer improves salt tolerance compared to unsubstituted acrylic acid polymers, enabling formulation with buffering salts and ionic actives
CIR Expert Panel concluded safe in the present practices of use and concentration (Fiume et al. IJT 2017, PMID 29025328) — same assessment clears 22 other crosslinked alkyl acrylate ingredients with the same split manufacturing-route qualification
Non-penetrating high-molecular-weight polymer — the molecular size prevents skin penetration, contributing to the low irritation and sensitization profile observed in clinical studies
Split CIR finding (SQ/UNS) — safe when not polymerized in benzene, but data do not support safety for grades polymerized in benzene. Legacy Carbopol 1342 specifications allowed up to 0.5% residual benzene (IARC Group 1 carcinogen); modern Pemulen and Ultrez grades use ethyl acetate or cyclohexane solvents and do not carry this concern. Formulators must specify non-benzene-polymerized raw material to satisfy the CIR safety conclusion
Residual benzene in legacy grades (documented in byproducts section) — average 0.25%, range 0.04-0.41% across 40 lots of Carbopol 1342 per supplier analysis cited in CIR 2017. Specifying a non-benzene-polymerized grade eliminates this concern entirely
Neutralization required for function — the crosspolymer must be neutralized with an alkali (commonly sodium hydroxide, triethanolamine, or aminomethyl propanol) to swell and deliver its rheology effect; unneutralized polymer is a low-viscosity acidic suspension
Electrolyte sensitivity — like other carbomer-family polymers, Acrylates/C10-30 Alkyl Acrylate Crosspolymer gels can collapse in the presence of high salt concentrations, which limits compatibility with electrolyte-heavy formulations (e.g. some preservative systems, some pH buffers)
CIR Quick Reference Table (12/2017, revised 07/2018) - Acrylates/C10-30 Alkyl Acrylate Crosspolymer row: Finding 'SQ/UNS' (split Safe Qua…
“Acrylates/C10-30 Alkyl Acrylate Crosspolymer | SQ/UNS | safe in the present practices of use and concentration when [not] polymerized in benzene; data does not support use when polymerized in benzene | IJT 36(Suppl.2):59-88, 2017”— QRT-122017revised072018.pdf, p. 3