Carbomer 940 and 980 are cross-linked polyacrylic acid polymers utilized in cosmetic grade carbomer formulations to build high viscosity at 0.5 percent concentrations while maintaining over 90 percent optical light transmittance at 420 to 700 nanometers.
Formulators evaluating 40,000 to 60,000 cP viscosity specifications often select synthetic polyacrylic acid polymers for transparent hydroalcoholic matrices.
Manufacturing pathways dictate regulatory approval limits because 1978 industrial protocols relied exclusively on benzene solvents.
Trace benzene residues exceeding 2 parts per million trigger strict toxicological recalls under 2024 European Commission directives.
Advanced production plants substitute benzene with ethyl acetate and cyclohexane co-solvent blends to comply with 0.1 percent residual limits.
| Parameter | Carbomer 940 | Carbomer 980 |
| Solvent | Benzene | Ethyl Acetate |
| Residue | < 2 ppm | Undetectable |
| Clarity | > 90% | > 92% |
| Yield Value | 500 Pa | 520 Pa |
Laboratory testing across 120 distinct batch samples demonstrates identical thickening efficiencies at neutral pH 7.0.
Neutralization requires precise amine titration using triethanolamine to uncoil polymer chains and develop maximum yield stress.
Insufficient base addition below pH 5.5 results in a 70 percent drop in measured Brookfield viscosity values.
Electrolyte tolerance remains a primary limitation for both variants when sodium chloride concentrations exceed 0.5 percent in aqueous solutions.
Formulations containing 1 percent sodium chloride exhibit a 45 percent viscosity reduction within 48 hours of storage at 25 degrees Celsius.
Shear thinning behavior allows fluids to dispense smoothly through standard orifices before recovering 80 percent of initial structure within 10 seconds.
Rotational rheometer tests performed at 20 RPM confirm pseudoplastic flow curves across 50 independent sample replicates.
Global brands transition away from legacy chemistries to satisfy 2026 safety standards established by major export destination markets.