Polyacrylate crosspolymer-6: properties, uses, INCI functions, safety

Polyacrylate crosspolymer-6 is a chemical compound, a high molecular weight synthetic copolymer that may contain traces of the solvent t-butyl alcohol. Polyacrylate crosspolymer-6 is incompatible with strong oxidants and is quite stable when stored at temperatures not exceeding 25°C.

The name describes the structure of the molecule:

• "Polyacrylate" refers to the polymer consisting of acrylate monomers. Acrylates are a family of compounds derived from acrylic acid, a type of organic acid.
• "Crosspolymer-6" indicates that it is a crosslinked polymer. Crosslinking is a process in which individual polymer chains are connected together to form a three-dimensional network.
•  The "6" in the name does not refer to a specific structural characteristic, but is a designation used by the manufacturer.

The synthesis process takes place in several stages:

• Step 1: Preparation of the monomer. The raw material for the synthesis of polyacrylate Crosspolymer-6 is acrylic acid or its derivatives. These monomers are prepared and purified before the polymerization process.
• Step 2: Polymerization. Monomers are polymerized to form a linear polyacrylate polymer. This is typically done using a process called free radical polymerization, where a small amount of a substance called an initiator is used to initiate the reaction.
• Step 3: Crosslinking. The linear polyacrylate polymer is then cross-linked to form Polyacrylate Crosspolymer-6. This is done using a curing agent, which reacts with polymer chains to connect them together.

It occurs as a fine, fine powder.

What it is used for and where

Medical

Polyacrylate crosspolymer-6 is used as a polymer that can be deposited on the outer layers of the skin or mucous membranes. It works with other ingredients and helps create a barrier to restore the skin and prevent loss and moisturise tissues (1).

Cosmetics

Polyacrylate crosspolymer-6 is often included in cosmetic formulations to protect or repair the skin as a thickening polymer that provides gel formation. Thickening and stabilising agent when many ingredients are present in a formula.  Typically, inclusion in the formula varies from 0.15% to 5%.

Viscosity control agent. It controls and adapts viscosity to the required level for optimal chemical and physical stability of the product and dosage in gels, suspensions, emulsions, solutions. 

Emulsion stabilizer. Emulsions are thermodynamically unstable. Emulsion stabilisers improve the formation and stability of single and double emulsions. It should be noted that in the structure-function relationship, molar mass plays an important role.

The inclusion of a UV protector in the formula increased the substantiality of the formulation and sun protection as the Polyacrylate crosspolymer-6 particles were exposed to water, formed a gel-like structure and remained even after drying. This water-reactive behaviour of the particles in the sunscreen has been shown to strengthen the integrity of the sunscreen film (2).

Commercial applications

Thickening Agent. Polyacrylate Crosspolymer-6 is used to increase the viscosity of cosmetic products, such as creams and lotions.

Emulsion Stabilizer. Helps to form and maintain stable emulsions in cosmetic formulations.

Gelling Agent. Used in cosmetic products to form high-quality and stable gels.

Film-Forming Agent. Forms a thin film on the surface of the skin or hair, enhancing appearance and providing protection.

Rheology Modifier. Alters the viscosity of cosmetic products, allowing for better application and feel on the skin.

Typical optimal characteristics of the commercial product Polyacrylate crosspolymer-6

Safety

Hazardous decomposition products: toxic fumes of carbon monoxide, carbon dioxide, nitrogen oxides and other gases may occur. Hazardous polymerization does not occur.

CAS    1439374-06-7

Synonyms

• Sepimax zen^TM
• Ammonium acryloyldimethyltaurate, dimethylacrylamide, lauryl methacrylate and laureth-4 methacrylate copolymer, trimethylolpropane triacrylate crosslinked (45000 MPA.S)

References_______________________________________________________________________

(1) Maggioni D, Cimicata A, Praticò A, Villa R, Bianchi FM, Busoli Badiale S, Angelinetta C. A Preliminary Clinical Evaluation of a Topical Product for Reducing Slight Rosacea Imperfections. Clin Cosmet Investig Dermatol. 2020 Apr 21;13:299-308. doi: 10.2147/CCID.S240784.

(2) Keshavarzi, F. (2020). Sweat resistance of sunscreens: Development of a perspiring skin simulator, evaluation of sunscreen failure mechanisms and enhancement of sunscreen substantivity. Technical University of Denmark.

Abstract. Sunscreen application is one of the most well-known solutions for the protection of human skin against harmful ultraviolet (UV) radiation from the sun. The substantivity of sunscreen (that is, the ability of the sunscreen to bind to the skin and resist removal), as an indicator of long-lasting protection against UV radiation, can be affected by a variety of activities, such as wearing clothes, swimming, and sweating, that may occur after the application of sunscreen on the skin. Sweating occurs in many situations in which people use sunscreen. However, the interaction of sunscreen and sweat is largely overlooked, likely owing to the inevitable challenges associated with performing in vivo sweat resistance tests and the lack of suitable instrumentation for in vitro studies. Besides active sweating, passive diffusion of water through the skin, known as transepidermal water loss (TEWL) can be affected by the application of topical films, such as sunscreen and polymeric film-forming systems. The aim of this PhD project was to develop specific in vitro setups to mimic human skin perspiration, and then to obtain general information on the impact of sweating on sunscreen substantivity, to evaluate the effect of different parameters on sunscreen failure mechanisms during sweating, and to explore methods to develop sunscreen formulations with greater sweat resistance. Moreover, a systematic evaluation of the breathability of film-forming systems applied on the skin was performed by using an in vitro TEWL simulator. The TEWL simulator was used to characterize the effect of the application of selected topical polymeric film formers on skin occlusion and TEWL. Subsequently, the in vivo TEWL studies were performed on two selected film formers. The comparison between the in vitro and in vivo TEWL studies confirmed that the TEWL simulator was able to predict the breathability of the polymeric filmforming systems. I used the perspiring skin simulator to perform both qualitative and quantitative evaluation of sunscreen film performance in response to sweating. The results showed that sweating negatively affected sunscreen substantivity and UV protection through wash-off and redistribution of the sunscreen film. Further, two approaches for increasing the sweat resistance of sunscreen were investigated: manipulation of the concentration of hydrophobic film-formers and incorporation of water absorbing particles in the sunscreen formulation. The results indicated that the combination of moderate concentrations of a hydrophobic film-former and water-absorbing particles capable of forming a gellike structure in contact with water could successfully increase the film integrity of sunscreen and control the sunscreen wash-off and redistribution by localizing the water pressure.