Introduction
Carbomer 980 is widely regarded as the gold standard for creating crystal-clear, high-viscosity gels in the cosmetic industry. It acts as a rheology modifier, meaning it controls the flow and texture of a product.
Unlike naturally derived gums that can feel sticky or stringy, Carbomer 980 creates a structured, “short flow” rheology. This results in products that pick up easily on a finger but spread easily across the skin without dripping.
For modern formulators, it operates as a critical upgrade to older polymers like Carbomer 940. While functionally similar, Carbomer 980 is synthesized in a co-solvent system of ethyl acetate and cyclohexane, making it benzene-free and safer for personal care applications.
Quick Facts
- INCI Name: Carbomer
- Function: Thickener, Suspending Agent, Stabilizer
- Typical Usage Rate: 0.2% – 1.0%
- Appearance: Fine, white, fluffy powder (hygroscopic)
- Solubility: Water-soluble (requires hydration and neutralization)
- Optimal pH: Thickens efficiently between pH 6.0 and 7.0
- Key Benefit: Creates sparkling, clear gels with excellent suspension power.
- Safety Note: acidic in solution (pH ~3); must be neutralized and preserved.
- Compatibility: Highly sensitive to electrolytes (salt) and cationic ingredients.
What is the Mechanism Behind Carbomer 980’s Viscosity?
To understand how Carbomer 980 thickens, one must look at its chemical structure. It is a cross-linked polyacrylic acid polymer. In its dry state, the molecule is tightly coiled up, similar to a compressed spring.
When dispersed in water, the polymer begins to hydrate and uncoil slightly. However, the real transformation occurs during neutralization. The polymer backbone contains numerous carboxylic acid (-COOH) groups.
The Uncoiling Effect (Neutralization)
When a base (neutralizer) is added to the dispersion, it reacts with the acidic groups. This reaction converts the carboxylic acid groups into carboxylate ions (-COO⁻).
Because these ions all carry a negative charge, they repel each other. This electrostatic repulsion forces the polymer chain to expand rapidly and drastically. The molecule uncoils fully, occupying a massive amount of volume in the water phase.
This expansion traps water molecules within the polymer network, creating high viscosity. This mechanism is why a Carbomer 980 solution is essentially water-thin at pH 3 but becomes a firm gel at pH 6.
Comparison with Carbomer 940
For decades, Carbomer 940 was the industry standard. However, it was polymerized in benzene, a known carcinogen. While the final product contained negligible residuals, the industry has moved toward safer synthesis routes.
Carbomer 980 was developed as a direct drop-in replacement. It offers the same high clarity plus suspension ability but is manufactured using toxicologically preferred solvents (Ethyl Acetate/Cyclohexane).
Formulators generally find that Carbomer 980 provides slightly more efficient thickening and better clarity in hydroalcoholic systems (like hand sanitizers) compared to older grades. It is the modern choice for clean beauty and safety-conscious brands.
Formulating with Carbomer 980: Best Practices
Successful formulation with Carbomer 980 relies heavily on the order of addition. The polymer must be completely dispersed and hydrated before any neutralization occurs.
If you add the neutralizer too early, the outer shell of the polymer particle will swell immediately. This blocks water from reaching the dry center, creating a permanent lump known as a “fish eye.”
Hydration and Dispersion Techniques
The most effective method for dispersion is to sift the powder slowly into an eddy of rapidly agitating water. This separates the individual particles, allowing them to wet out evenly.
Once dispersed, the solution needs time to hydrate. Depending on the batch size and temperature, this can take 20 to 30 minutes. The mixture will appear hazy and slightly foamy at this stage.
Using warm water (around 40°C – 50°C) can accelerate hydration, but excessive heat is unnecessary. Once the polymer is fully hydrated, the solution should look uniform, even if it is not yet clear or thick.
The Art of Neutralization
Choosing the right neutralizer depends on the desired pH and the alcohol content of your formula. For simple aqueous gels, Sodium Hydroxide (NaOH) or Triethanolamine (TEA) are standard choices.
For formulations containing high levels of ethanol (like sanitizers) or those requiring a specific pH buffer, Tromethamine or AMP-Ultra (Aminomethyl Propanol) are preferred.
You typically need a ratio of roughly 2.3 parts TEA to 1 part Carbomer, or 0.4 parts NaOH to 1 part Carbomer. Always add the neutralizer slowly while mixing to prevent localized shocking of the polymer.
Overcoming Common Formulation Challenges
While Carbomer 980 is powerful, it is chemically fragile in certain environments. The most common reason for formulation failure is the loss of viscosity due to ionic interference.
The electrical repulsion that keeps the gel structure expanded is easily disrupted by ions. Dissolved salts act as a shield between the negative charges, causing the polymer to collapse back into a coiled state.
Electrolyte Sensitivity and Stability
Ingredients rich in electrolytes, such as Aloe Vera juice, sodium lactate, or botanical extracts with high mineral content, can liquefy a Carbomer gel instantly. Even hard tap water containing calcium and magnesium can prevent thickening.
To reduce this, always use distilled or deionized water. If you must use ionic ingredients, you may need to use an acrylate copolymer (like Carbomer Ultrez 20 or 21) designed to tolerate moderate electrolyte loads.
Alternatively, increase the Carbomer 980 concentration slightly (to 1.0% – 1.2%) to compensate for the drop in viscosity, though this has limits. Testing stability with all actives included is mandatory.
Troubleshooting Texture Issues
Achieving that perfect, glass-like aesthetic requires troubleshooting both processing and chemistry. Below is a guide to fixing common textural defects in Carbomer gels.
Table: Common Carbomer Problems and Fixes
| Problem | Potential Cause | Immediate Fix |
| “Fish Eyes” (Lumps) | Polymer added too fast or neutralized too early. | Pre-disperse in oil/glycerin or sift slowly into vortex. |
| Hazy / Cloudy Gel | Trapped air or incomplete hydration. | Vacuum mixing or allow to stand 24hrs; Ensure pH is > 6.0. |
| Runny / No Viscosity | High salt content or pH is too low (< 5.0). | Switch to distilled water; Add more neutralizer to reach pH 6-7. |
| Grainy Texture | “Shocking” the polymer with base. | Dilute neutralizer in water before adding; mix rapidly. |
| Viscosity Drop Over Time | UV degradation or bacterial enzyme activity. | Add UV absorber (Benzophenone-4); Ensure robust preservation. |
FAQ’s about Carbomer 980 in Skincare: Science Behind Its Gel-Forming Power
What is the difference between Carbomer 940 and 980?
Carbomer 980 is the modern, benzene-free version of Carbomer 940. While they provide nearly identical viscosity and clarity, Carbomer 980 is synthesized in an ethyl acetate/cyclohexane cosolvent system, making it safer for personal care products and compliant with stricter global safety regulations regarding solvent residuals.
Can I use Carbomer 980 in organic formulations?
Carbomer 980 is a synthetic polymer and is not considered “natural” or “organic” by standards like COSMOS or Ecocert. However, it is widely accepted in “clean beauty” because it is biodegradable, non-toxic, and effective at very low percentages, reducing the overall chemical load of a product.
Why did my Carbomer gel turn to liquid when I added salt?
Carbomer 980 is extremely sensitive to electrolytes. Salt (Sodium Chloride) introduces ions that shield the negative charges on the polymer backbone. This stops the electrical repulsion that holds the gel structure open, causing the polymer coils to collapse and the viscosity to drop immediately.
How do I reduce bubbles in my Carbomer gel?
Air bubbles are easily trapped during the neutralization phase when viscosity builds rapidly. To prevent this, mix at a moderate speed using a paddle agitator rather than a high-shear whisk. If bubbles occur, allow the batch to sit covered for 24 hours, or use a vacuum mixer to pull the air out.
What is the best pH for Carbomer 980?
The optimal viscosity for Carbomer 980 is achieved in the pH range of 6.0 to 7.0. Below pH 5.0, the carboxyl groups are not fully ionized, leading to lower viscosity. Above pH 9.0, the presence of excess ions can begin to reduce viscosity again through the shielding effect.
Does Carbomer 980 need a preservative?
Yes, absolutely. While the dry powder is not a food source for bacteria, once hydrated in water, the gel is susceptible to microbial proliferation. Furthermore, some bacteria produce enzymes that can break down the polymer chain, causing the product to lose viscosity over time.
Can I mix Carbomer 980 with Vitamin C?
It is difficult. L-Ascorbic Acid (Vitamin C) is an electrolyte and requires a low pH (around 3.0) to remain stable. Carbomer 980 needs a neutral pH (around 6.0) to thicken and cannot handle the ionic load of Vitamin C. You would need a hydrophobically modified acrylate or a different gum for this application.
Is Carbomer 980 safe for skin?
Yes, it is considered very safe. The polymer itself is too large to penetrate the skin barrier. It sits on the surface and is non-irritating and non-sensitizing. However, because it is acidic before neutralization, the raw mixture must always be pH-adjusted before application to the skin.