Carbomer is a term used for a series of polymers primarily made from acrylic acid. Carbomers are white, fluffy powders but are frequently used as gels in cosmetics and personal care products.

Carbomers can be found in a wide variety of product types including skin, hair, nail, and makeup products, as well as dentifrices.

Features

The molecular weight of carbomer is estimated to be at 7×105 to 4×109 Da. As three-dimensionally cross-linked microgels, carbomers do not dissolve but swell to a remarkable extent in water after neutralization to form a gel.80 Carbomers are used in liquid or semisolid pharmaceutical formulations as rheology modifiers. Carbomers having low residual solvent content, such as Carbopol 971P NF or Carbopol 974P NF, may be used in oral solid dosage forms as binders or matrix tablet formers. 

Applications

The dominant application for PAA is as a superabsorbent. About 25% of PAA is used for detergents and dispersants.

Polyacrylic acid and its derivatives are used in disposable diapers. Acrylic acid is also the main component of Superadsorbent Polymers (SAPs), cross-linked polyacrylates that can absorb and retain more than 100 times of their own weight in liquid. The US Food and Drug Administration authorised the use of SAPs in packaging with indirect food contact. 

Detergents often contain copolymers of acrylic acid that assist in sequestering dirt.Cross-linked polyacrylic acid has also been used in the processing of household products, including floor cleaners. PAA may inactivate the antiseptic chlorhexidine gluconate.

The neutralized polyacrylic acid gels are suitable biocompatible matrices for medical applications such as gels for skin care products. PAA films can be deposited on orthopaedic implants to protect them from corrosion. Crosslinked hydrogels of PAA and gelatin have also been used as medical glue.

Other applications involve paints and cosmetics. They stabilize suspended solid in liquids, prevent emulsions from separating, and control the consistency in flow of cosmetics. Carbomer codes (910, 934, 940, 941, and 934P) are an indication of molecular weight and the specific components of the polymer. For many applications PAAs are used in form of alkali metal or ammonium salts, e.g. sodium polyacrylate.

Side effects

This ingredient has been assessed as safe to use in cosmetic products. In reviewing acute oral and dermal studies, they determined that carbomers have a low potential for phototoxicity, photo-contact allergenicity, skin irritation and sensitization at concentrations up to 100%.