Formulation Guides: Selection of Thickeners in Cosmetics

Outline

Understanding the Role of Thickeners

Thickeners are essential ingredients in cosmetic formulations, influencing product texture, stability, and overall sensory experience. They increase the viscosity of liquid formulations, transforming them into creams, gels, lotions, and other desired consistencies.

Specifically, after the thickener is dissolved or dispersed in water, it can increase the viscosity of the liquid and maintain the relative stability of the system. The molecular structure contains many hydrophilic groups, such as -OH, -NH₂, -COOH, -COO, etc., which can react with water molecules to form a high-viscosity macromolecular solution.

Main characteristics of thickeners

• Viscosity Control
• Texture Enhancement
• Stability Improvement
• Sensory Experience

Categories of Thickeners

• According to water solubility: water-soluble thickener, micropowder thickener.
• According to sources: natural thickener, synthetic thickener.
• According to use: water-based thickener, oily thickener, acidic thickener, alkaline thickener.

Hot Thickeners from Alfa Chemistry

Principle of Thickener Action

Since the functional groups on the polymer chain are generally not single, a thickener may have multiple thickening mechanisms at the same time.

Chain Entanglement Thickening

After the polymer is placed in the solvent, the polymer chains curl and entangle with each other, and the viscosity of the solution increases. After neutralization with alkali or organic amine, the negative charge has strong water solubility, making the polymer chain easier to unfold, thereby increasing the viscosity.

• Common examples: poly(meth)acrylic acid, polyacrylamide, polyethylene/propylene oxide, polyvinyl alcohol, polyvinyl pyrrolidone, etc.
• Applicability: Mainly solution thickening, no pseudoplasticity, poor skin feels, not suitable for multi-scenario applications.

Covalent Cross-Linking Thickening

Some thickeners form covalent bonds between polymer chains to form a rigid network. This network structure significantly increases the viscosity of the formula.

• Common examples: Carbomer, acrylates, etc.
• Applicability: The system has a wide range of applications, and its skin feel and viscosity are widely applicable.

Associative Thickening

Associative thickeners have both hydrophilic and hydrophobic groups. In aqueous solution, these molecules form micelles, in which the hydrophobic groups gather together and the hydrophilic groups interact with water, thereby increasing the viscosity of the solution.

• Common examples: Hydrophobically modified acrylate associative thickeners, hydrophobically modified cationic acrylate associative thickeners, hydrophobically modified polyether associative thickeners.
• Applicability: The thickening conditions need to meet the requirements and be suitable for specific formulation scenarios.

What Factors Affect the Choice of Thickeners?

There are many factors that formulators need to consider when choosing thickeners:

• The main body of the formula is the primary consideration for choosing a thickener, and what kind of system determines what kind of thickener to use. Different cosmetics require different viscosities to achieve their intended functions.
• The second is the product form, which requires different types of thickeners. Some require Newtonian fluids, some require plastic fluids, and different thickeners are used according to different needs.
• The proportion of thickeners in the final product and the cost of the formula are also important factors in the selection of thickeners. It is very necessary to balance the effect of the thickener and its cost.
• In addition, the physical and chemical indicators of the formula must also be considered when selecting a thickener, such as the stability of the formula, foam, etc. Although some thickeners have ideal thickening effects, they are worthless if they have poor stability or too strong defoaming.
• In general, the coordinated thickening of several thickeners has a better effect on the final rheological form of the product than using a single thickener.

What can Alfa Chemistry do for you?

• Cosmetic Testing
• Stability Testing for Cosmetics
• Formulation Development

Case Study of Carbomer Thickener

Carbomer is one of the most popular thickener raw materials on the market. Powdered carbomer polymers have properties such as thickening suspension, antibacterial, transparency, and controllable rheology. So, how does it work in cosmetic formulations? Here, Alfa Chemistry shares with you the basic formulation case of carbomer in cream applications.

Formula process

• Heat phase (A) and phase (B) to 80℃ respectively.
• Add (B) to phase (A) and homogenize.
• Cool phase (AB) to 40 ℃ and add phase (C) while stirring.
• Adjust the required pH value (pH recommended 6.5~7.0).

The formula was finally proved through experimental heat storage stability test (50 ℃, 4w) and skin feel comparison that carbomer thickener brings sensory effects such as good thickening effect, good viscosity stability and strong moisturizing to the cream.

Experience Sharing: Synergistic Effect of Magnesium Aluminum Silicate Thickener

• Magnesium aluminum silicate and anionic naturally derived thickeners usually show the best compatibility and synergy.
• Xanthan gum can enhance the fluidity, suspension efficiency, and compatibility of electrolytes, acids, and bases of magnesium aluminum silicate dispersions.
• Magnesium aluminum silicate has strong synergy with sodium carboxymethyl cellulose, provideng high yield value, high viscosity, good electrolyte compatibility, and good high temperature viscosity stability.
• Magnesium aluminum silicate has synergy with carrageenan in thixotropic viscosity and yield value.
• Magnesium aluminum silicate has strong synergy with polyacrylate in viscosity and yield value (forming rigid gels and thick pourable systems).
• Magnesium aluminum silicate generally shows limited compatibility with carbomer and tends to cause flocculation of carbomer.

Online Inquiry

mg g kg ml L

Formulation Guides: Selection of Thickeners in Cosmetics

SUBMIT