What is carbomer?
Carbomer is a kind of polymer formed by chemical cross-linking of acrylic acid or acrylate with allyl ether, including polyacrylic acid (homopolymer) and long-chain alkyl alcohol acrylate polymer (copolymer). Its molecular structure contains 52 ~ 68% acid groups, so it has certain acidity and hydrophilicity, and can be soluble in water, ethanol and glycerol. Carbomer has the functions of thickening, suspending, stabilizing the system, regulating the release of water and active substances, and has simple process and good stability, so it is a kind of rheological modified thickener which is widely used in personal care products, pharmaceuticals and other fields.
Carbomer, a fine white acrylic powder, is an ingredient in hair gels, lotions, and balms, among others. It can be utilized in the formulation of transparent and scintillating gels, in addition to emulsion stabilization. 0.1–0.5% is the typical application level, contingent upon the formulation type and ultimate viscosity objective. It is a pH-sensitive thickener that is also economical. Carbomer is a polymer soluble in both alcohol and water. It is mildly acidic and, when partially neutralized to a pH between 5 and 8, forms a porous network. Carbomer must enlarge for an extended period of time prior to use. It is optimal to prepare a pre-gel prior to starting the current production. It is applicable to hair products, lotions, and lubricants, among others. Carbomer, which is composed of polyacrylic acid, is offered in an extensive variety of molecular weights and in branched, linear, or cross-linked forms. In water, the acidic carboxyl groups dissociate in part, resulting in the formation of a flexible filament. Gel formation is believed to be caused by solvation, salt formation, and electrostatic repulsion between the anionic groups when alkaline compounds are added. The hydrophobic carbomer exhibited an elevation in texture profile parameters and viscosity as the concentration of Polysorbate 80 was increased to 0.3% w/w. However, as the surfactant concentration continued to rise, the gel network strength exhibited a decline. Conversely, the network structure of the unmodified, hydrophilic carbomer (Carbopol 934P®) exhibited marginal alterations as the surfactant concentration increased; thus, the interactions between emulsifier and surfactant are hydrophobic in nature, concentration-dependent, and influence the rheological properties of the dispersion. It was discovered that the time-dependent release or bioavailability of the active constituent utilized in drug delivery systems is influenced by the rheological properties of carbomer systems.
Gels made from acrylic acid synthetic polymers, such as Carbomer-940, Carbomer-980, and other Carbomer homopolymers, exhibit promise as possible substitutes for agar gels. Specialized equipment was not needed for the preparation of the gels, and the final product remained stable and solid for an extended duration. The manufacture of the affordable, non-hazardous gelling agents was quite simple and simply required pre-measuring the water and dry chemical, mixing, and final pH adjustment to get the correct viscosity.
What is carbomer used for?
Due to its vast variety of features and applications, carbomer is a synthetic polymer that finds widespread use in many industries. These include the cosmetics, pharmaceutical, and personal care product sectors:
(a)Carbomer is mainly used to manufacture creams, lotions, gels, and serums since its well-known thickening characteristics. Carbomer increases the consistency and texture of formulations by increasing their viscosity. This makes them easier to spread and gives them a sumptuous feel when applied.
(b)Carbomer keeps emulsions like creams and lotions from separating into their oil and water components and keeps the formulation stable as a whole. As a result, products stay uniform and aesthetically pleasing for a longer period of time, which increases their shelf life.
(c) Carbomer helps oils and water phases in formulations emulsify, making it possible to create stable emulsions. The blending of chemicals is crucial in products like sunscreens and moisturizers to get the ideal texture and performance, thus this is especially critical in those cases.
(c) Thin, transparent film can be formed on the skin’s surface by using carbomer, which has film-forming capabilities. In addition to protecting the skin from harmful environmental factors including pollution and UV radiation, this coating also helps to seal in moisture and prevent its loss.
(d) Carbomer acts as a rheology modifier in topical formulations like ointments and gels. This guarantees that the formulation glides smoothly over the skin, allowing the active ingredients to be applied and absorbed uniformly.
Summary of the physicochemical properties of carbomers. (Singla A K., et al., 2000)
Two main thickening mechanisms of carbomer
Neutralization and thickening
Because it contains certain acid groups, alkaline neutralization is needed in the process of application. The carboxyl group of the alkaline neutralized carbo resin is ionized. Due to the mutual repulsion of negative charges, the curled molecular chain extends in a state of great expansion, which increases the original volume to about 1000 times, thus plays a role in thickening. The commonly used neutralizers are sodium hydroxide, potassium hydroxide, potassium bicarbonate and triethanolamine (a glittering and translucent gel can be obtained when the pH is adjusted to about 7), which is why Carbomer is sensitive to ions.
Hydrogen bond thickening
Carbomer, as a carboxyl donor, can combine with one or more hydroxyl groups to form hydrogen bonds and thicken. This reaction mechanism takes time. The commonly used hydroxyl donors are Nonionic surfactants, polyols and so on.
Carbomer at BOC Sciences
| Product Name | CAS Number |
| Carbomer | 9007-20-9 |
| CARBOMER 981 | 138757-68-3 |
| Carbomer 980 | 139637-85-7 |
| Carbomer 934P | 57916-92-4 |
| SODIUM CARBOMER | 73298-57-4 |
| Carbomer 940 | 76050-42-5 |
| Carbomer 934 | 9007-16-3 |
| Carbomer 941 | 9602-04-8 |
| Carbomer 962 | 91315-33-2 |
| Carbomer 1342 | 96827-24-6 |
Performance and Application of Common Carbomer Series
According to the degree of cross-linking and molecular weight, Carbomer has a variety of products of different types, including traditional series of Carbopol 910,934,934p, 940,941,954, as well as new polymers such as Carbopol Ultrez 20 / 21. Different types of carbomers have different uses in different industries because of their different suspension stability and fluidity changes.
Traditional Carbomer
Carbopol 934 (benzene solvent homopolymer)
Appearance: White loose powder, slightly odor.
Properties: short rheology; medium and high viscosity; medium transparency, slightly yellow; low ion resistance; high shear resistance; suspension stability, high heat resistance.
Safety: possible residual solvents (benzene or xylene).
Application: suitable for high viscosity gel, lotion and ointment; suspension and emulsification; local application; skin care; hair care; taste masking; cream; hand, body and facial lotion. It is widely used in pharmaceutical (ointment) formulations and cosmetic creams.
Carbopol 940 (benzene solvent homopolymer)
Carbomer 940 is a polymer made from acrylic acid that is cross-linked. It is mainly used to thicken and stabilize various products. The substance is provided in the form of a white, soft powder that has a strong tendency to absorb moisture from the environment. Carbomer 940, when mixed with water or aqueous solutions, creates gels that are either transparent or translucent. These gels have a high viscosity, which gives formulations a desired texture and consistency.
24 hours after burn initiation, blood flow in the zone of stasis increased in the experimental group treated with carbomer 940 hydrogel in the rat model of skin burn wound. Significant differences (p<0.05) were observed between the outcomes of the experimental and control groups at the 24, 48, and 72-hour marks. Histopathologically, the experimental group treated with Carbomer 940 hydrogel exhibited a significantly greater amount of epithelial tissue in the zone of stasis compared to the control group. Additionally, the group treated with hydrogel maintained viable sebaceous glands and hair follicles. In rats, carbomer 940 hydrogel enhanced tissue perfusion and reduced the extent of necrotic epidermis within the zone of stasis.
Appearance: White loose powder, slightly odor.
Properties: (jelly) extremely short rheological property; high viscosity; high transparency; low ion resistance; low shear resistance; high yield value (suspension capacity).
Solubility: soluble in water, glycerol, ethanol, etc.
Safety: no mold will grow in dry state, non-toxic and non-irritating.
Application: it can provide the stability of oil-in-water emulsion system, which is suitable for emulsion and cream.
Recommended dosage: 0.2% ~ 1.5%.
Carbopol 941 / 971 (benzene solvent homopolymer)
Appearance: White loose powder, slightly odor.
Properties: (slug type) long rheology; low viscosity; high transparency; medium ion resistance; low shear resistance.
Solubility: soluble in water, glycerol, ethanol, etc.
Application: can produce low viscosity permanent emulsions and suspensions, or even ionic systems, resulting in good colloid transparency (more effective at low concentrations). Carbo 941 is used as a stabilizer for oil-in-water emulsion systems in the cosmetics industry, and 971 as a sustained-release agent in the pharmaceutical industry, suitable for transparent gels, water-alcohol gels and emulsion products.
Modified carbomer (no benzene)
Carbopol 980 (co-solvent homopolymer)
For topical use on the skin, Carbomer 980 (C980) offers formulations that are clear and gel-like, and they are dissolved in water. In spite of the fact that there are some modest variations in the viscosity of the dispersion that are associated with the cross-link density (high for C980 and medium for C974), these polymers can be used interchangeably for the creation of topical formulations in water that are intended to be applied to individuals’ skin. When hydroalcoholic media are utilized, it is possible to differentiate between the two carbomers that were analyzed in terms of their respective applicability. In fact, C980 demonstrated a higher level of solvation than C974 in hydroalcoholic media that contained a percentage of alcohol (ethanol or isopropanol) that was greater than fifty percent by weight. This ensures that gels have a higher viscosity and transparency, as demonstrated by the results obtained from the determination of viscosity and the analysis of transmittance. Therefore, C980 and possibly other carbomers with a high crosslink density (for example, Ultrez 10 NF, which is a carbomer interpolymer) need to be recommended for the creation of formulations that contain a large amount of alcohol, such as hand sanitizers. In point of fact, these carbomers render goods that are transparent to the human eye and offer the opportunity to modify the viscosity in accordance with the concentration of the polymer, even at alcohol concentrations that are rather close to CAlC, in the event that it is required.
Variation of the calculated power law viscosity for C980 (0.2% w/w) dispersions. (Berardi A., et al., 2022)
Blood flow increased in Carbomer 940 hydrogel rats 24 hours postburning. (Hayati F., et al., 2016)
Chemical name: cross-linked polyacrylic resin.
Appearance: White loose powder, slightly odor.
Properties: very short rheological property; high viscosity; high transparency; low ion resistance; low shear resistance; high yield value (suspension capacity).
Solubility: soluble in water, glycerol, ethanol, etc.
Application: suitable for thickening, suspension and emulsification in cosmetics or pharmaceutical formulations. Such as: setting gel, water alcohol gel, moisturizing gel, bath gel, toothpaste, shampoo, shaving gel, moisturizer and sunscreen, etc.
Dosage: 0.2% ~ 1.5%.
Carbopol 1342 (hydrophobically modified copolymer)
Chemical name: cross-linked polyacrylic resin.
Appearance: White loose powder.
Properties: long flow characteristics; medium viscosity; high transparency; high ion resistance; high shear resistance; high yield value (suspension capacity).
Solubility: soluble in water, glycerol, ethanol, etc.
Application: excellent rheological improver in the presence of electrolyte, polymerization and emulsification, suitable for aqueous solution or dispersion containing water-soluble salt.
arbopol ETD 2020
Chemical name: acrylate / C10-30 alkyl acrylate cross-chain copolymer.
Appearance: White loose powder.
Properties: long rheology; medium viscosity; high transparency; high ion resistance; shear resistance; efficient thickening, strong suspension capacity.
Application: suitable for transparent gel, water-alcohol gel, surfactant system (special shampoo, cleaning products, etc.) and systems with high electrolyte content (such as aloe gel).
Recommended dosage: 0.2% ~ 1.5%.
Carbopol AQUA SF-1
A New Rheological modifier for liquid Acrylic Acid.
INCI name: acrylic acid (ester) copolymers.
Appearance: milky white to white liquid.
Properties: long rheology; high viscosity; medium transparency (opaque body, after adding the product); low ion resistance; high shear resistance.
Solubility: soluble in water, glycerol, ethanol, etc.
Application: can prepare clear formula, excellent compatibility with a variety of components, acid thickening, can be used in surfactant system.
Carbomer homopolymer
One subset of carbomers, known as carbomer homopolymers, is composed of a single monomer unit, most often acrylic acid or methacrylic acid. Being a homopolymer means that its three-dimensional network structure is formed entirely by covalently linked repeating units of the same monomer. Carbomer homopolymers have distinct rheological characteristics due to their cross-linked structure and high molecular weight. The powders are usually white and fluffy, and they are very hygroscopic, meaning they absorb water easily. When mixed with water, they create gels that are either clear or translucent.
Carbopol Ultrez 20 (a new type of easily dispersed copolymer)
Chemical name: acrylate / C10-30 alkyl acrylate cross-chain copolymer.
Appearance: White loose powder.
Properties: long rheology; high transparency; medium viscosity; medium ion resistance; high shear resistance; easy dispersion, excellent and stable suspension ability.
Application: can be used in shampoo, bath gel, cream, lotion, hydrogel with high electrolyte. In addition, the U20 can also give the product a bright appearance, with better fluidity and tipping, providing the product with a smooth, light and soft touch.
The efficacy and function of Carbomer
Carbomer in skin care
Carbomer is useful in hygiene products that aim to form a protective barrier on the skin’s surface due to its film-forming properties. This barrier prevents moisture loss, aids in moisture retention, and protects the epidermis from environmental stresses such as UV radiation and pollutants. To augment the effectiveness of skincare formulations that target particular concerns (e.g., aging or acne), carbomer may be blended with additional active constituents. Due to its broad compatibility with skincare ingredients, this component exhibits remarkable versatility as it is incorporated into formulations that target distinct skin types and conditions. Carbomer, which is widely recognized for its ability to thicken substances, is an essential component in creams, moisturizers, gels, and serums, enhancing the viscosity and texture of these formulations. Due to its capacity for water absorption and retention, it is utilized extensively in the formulation of hydrating products that supply the epidermis with sustained moisture.
Carbomer has an obvious protective effect on human skin, it has a certain affinity to human skin, usually, people add it to cosmetics, later use, can protect the skin, and can reduce irritating substances, stimulation and injury to human skin and skin mucosa, can prevent the occurrence of a variety of allergic symptoms.
Anti-ultraviolet radiation
Carbomer has a certain activity after it is applied on the surface of human skin, it can enhance the resistance of human skin to ultraviolet rays and reduce the damage of ultraviolet rays to human skin. Carbomer’s sunscreen is added in the summer. It will play a particularly ideal sunscreen effect, can prevent the skin from blackening and can also prevent the skin from being burned by ultraviolet rays.
Reduce viscosity
Carbomer has a certain degree of looseness, and it is a kind of slightly acidic substance with strong hygroscopicity. Usually, an appropriate amount of Aunt Han can be added when making gel or cosmetics, which can reduce the viscosity of these substances and maintain their stable properties. Carbomer is an important raw material for making cosmetics and gel in current industrial production.
Anti-inflammation and sterilization
Carbomer is also a natural medicinal ingredient, which can reduce inflammation and sterilization. Carbomer eye drops sold on the pharmaceutical market are drugs made from it as the main raw material. It has a good effect on the elimination of human eye inflammation and can quickly relieve the pain and redness and swelling of the eyes.
Ensure the quality of cosmetics
Carbomer is a chemical neutralizer, which plays a very important role in the production of cosmetics. It can integrate a variety of ingredients in cosmetics and keep them in a stable and appropriate state. And the cosmetics added with carbomer will have a good matrix, and people will feel very comfortable after applying it on the skin.
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References
1. Singla, A. K., Chawla, M., & Singh, A. (2000). Potential applications of carbomer in oral mucoadhesive controlled drug delivery system: a review. Drug development and industrial pharmacy, 26(9), 913-924.
2. dos Santos, R. S., Rosseto, H. C., da Silva, J. B., Vecchi, C. F., Caetano, W., & Bruschi, M. L. (2020). The effect of carbomer 934P and different vegetable oils on physical stability, mechanical and rheological properties of emulsion-based systems containing propolis. Journal of Molecular Liquids, 112969.
3. Singla A K., et al.,Potential applications of carbomer in oral mucoadhesive controlled drug delivery system: a review, Drug development and industrial pharmacy, 2000, 26(9): 913-924.
4. Al-Malah K. Rheological properties of carbomer dispersions, Annual Transactions-Nordic Rheology Society, 2006, 14: 123.
5. Hayati F., et al.,Carbomer 940 hydrogel enhances capillary blood flow and tissue viability in a skin burn wound,
6. Berardi A., et al.,Factors affecting the rheological behaviour of carbomer dispersions in hydroalcoholic medium: Towards the optimization of hand sanitiser gel formulations, International Journal of Pharmaceutics, 2022, 616: 121503.