I hope this article demystifies the base coat as it pertains to the nail industry. A base coat is normally the first layer in a professional nail polish application. This layer adheres to the coated surface, called the substrate, which is the nail plate.
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Vivian B. Valenty, Ph.D., provides insight on base coats.
I hope this article demystifies the base coat as it pertains to the nail industry. A base coat is normally the first layer in a professional nail polish application. This layer adheres to the coated surface, called the substrate, which is the nail plate.
For this article, I inspected the ingredient lists published online of numerous base coats on the market and will report my findings here. I narrowed the choice for discussion to seven base coats used in solvent-based traditional nail polishes and excluded those for UV-cured systems. I assume the ingredients published online are accurate and comply with FDA labeling guidelines per the Federal Food, Drug, and Cosmetics Act of 1938.
Sticking To The Nail Plate
The primary role of the base coat is to ensure the polish sticks to the nail plate. In any coating system, all the layers must be compatible with each other to thoroughly and uniformly wet the layer immediately underneath it for the layer to stick. Because the base coat is the first film to contact the nail plate, its compatibility with the nail surface is essential. The following factors affect the compatibility of the base coat with the nail plate.
- The surface must be clean of materials that detract from its compatibility with the coating. Like begets like. As a water-loving or hydrophilic surface, the nail plate prefers base coats with polar groups. Oils and debris left on the nail surface are oil-loving and will repel the base coat, leading to poor adhesion.
- The chemical bonds exposed on the nail surface are polar and must interact with the polar chemical groups of the film-forming component of the base coat for good adhesion.
- The nail and the base coat interaction must be strong enough to retain adhesion appropriately.
- The mechanical properties of the primary film former are important. A base coat with a mechanically hard or stiff primary film former with strong adhesion to the nail could pull the keratin layers away from each other and damage the nail plate surface. The damage is manifested as delamination, white spots or white patches.
Other Base Coat Roles
So, what other roles do base coats play in a professional nail polish application? They act as ridge fillers to smooth out the imperfections of the nail plate’s surface. They could shield the nail plate from pigments penetrating and causing staining. They also could prevent the polish from cracking and, therefore, extend the wear time. They could provide some benefits to the nail’s health, although this benefit is controversial.
This article will discuss seven base coats on the market with their published ingredients available online.
Nitrocellulose is the most common primary film former. Base coats containing nitrocellulose could prevent the nail plate from getting stained by the pigments but will not prevent the nails from turning yellow. Nitrocellulose is also the primary film former in traditional polish and is the cause of nails turning yellow due to its degradation product nitric acid, a strong oxidizer.1 Therefore, these base coats will not prevent natural nails from turning yellow.
Base Coat A
Ethyl Acetate, Butyl Acetate, Alcohol Denat., Nitrocellulose, Adipic Acid/Neopentyl Glycol/Trimellitic Anhydride Copolymer, Isopropyl Alcohol, Trimethylpentanediyl Dibenzoate, Acetyl Tributyl Citrate, Sucrose Acetate Isobutyrate, Etocrylene, Retinyl Palmitate, Tocopheryl Acetate, Dimethicone, Biotin, Calcium Pantothenate, Glycerin, Equisetum Hiemale Extract, Glycidoxypropyl Trimethoxysilane, Methacryloyl Propyltrimethoxysilane, Methyltriethoxysilane, Mercaptopropyltrimethoxysilane, Ascorbic Acid, CI 60725 (Violet 2).
Analysis. This is a solvent-based base coat consisting of ethyl acetate, butyl acetate and alcohol denat (denatured ethyl alcohol). Nitrocellulose is a primary film former made of cellulose from cotton or wood fiber chemically modified with nitro groups. Nitro groups are strongly ionic or polar and will have an affinity towards the natural nail plate. Its film properties are modified by the secondary film former adipic acid/neopentyl glycol/trimellitic anhydride copolymer and the plasticizers trimethylpenatanediyldibenzoate, acetyl tributyl citrate and sucrose acetate isobutyrate. It contains the UV absorber etocrylene, and the antioxidants retinyl palmitate, tocopheryl acetate and ascorbic acid. Biotin, calcium pantothenate, glycerin and equisetum hyemale (horsetail) extract (misspelled in published ingredient list as hiemale) are present to possibly contribute to the nail’s health. In addition, base coat A contains four silane adhesion promoters which are highly reactive to water and other polar groups. Because of their reactivity, with several polar ingredients in the product, I doubt if these silanes contribute to the base coat’s adhesion. Furthermore, this base coat contains dimethicone which is not good for adhesion.
Base Coat B
Butyl Acetate, Ethyl Acetate, Nitrocellulose, Acetyl Tributyl Citrate, Adipic Acid/Neopentyl, Anhydride, Copolymer, Isopropyl Alcohol, Stearalkonium Bentonite, Acrylates Copolymer, Styrene/Acrylates Copolymer, Benzophenone-1, Caprylic/Capric Triglyceride, Trimethylpentanediyl DIbenzoate, Hexanal, Punica Granatum Seed Oil, Polyvinyl Butyral, Isopropyl Myristate, Helianthus Annuus (Sunflower) Seed Helianthus, Annuus Seed Oil, Glycerin, Propylene Glycol, Water, Pistacia Lentiscus (Mastic) Gum Oil, Lauraldehyde, Tocopheryl Acetate, Glyceryl Linoleate, Vitis Vinifera (Grape) Fruit Extract, Calcium Pantothenate, Zinc Acetylmethionate, Citrus Lemon, Glyceryl Linolenate, Retinyl Palmitate, Brassica Oleracea Acephala Leaf, Viti, Panax Ginseng Root Extract, Magnesium Ascorbyl Phosphate, Ferric Ammonium Ferrocyanide CI 77510, Aloe Barbandensis Leaf Extract, Yellow 5 Lake CI 19140, Biotin, Tocopherol, Sodium Benzoate, Glycine Soja (Soybean) Oil.
Analysis. The primary film former listed in base coat B is nitrocellulose with the secondary film formers adipic acid/neopentyl anhydride copolymer, acrylates copolymer, styrene/acrylates copolymer and polyvinyl butyral. It contains oils, plant extracts and antioxidants to possibly benefit nails. Zinc acetylmethionate could increase adhesion, but nitrocellulose degrades in the presence of water to form nitric acid which turns nails yellow.
Base Coat C
Ethyl acetate, butyl acetate, nitrocellulose, toluenesulfonamide/formaldehyde resin, isopropyl alcohol, n-butyl alcohol, trymethyl penthanyl, dissobutyrate, camphor, hydrolized wheat protein, hydrolized keratin, hydrolized soy protein, calcium pantothenate. (This ingredient list contains several misspellings, which I left unedited.)
Analysis. Toluenesulfonamide/formaldehyde resin modifies the primary film former nitrocellulose to increase adhesion and extend the polish’s wear time. This resin has been reported to cause allergies2 in traditional polish wearers. Base Coat C contains hydrolyzed proteins to possibly benefit the nails.
Base Coat D
Ethyl Acetate, Butyl Acetate, Nitrocellulose, Propyl Acetate, Tosylamide/Formaldehyde Resin, Isopropyl Alcohol, Triphenyl Phosphate, Trimethyl Pentanyl Diisobutyrate, N-Butyl Alcohol, Formaldehyde, Stearalkonium Bentonite, Camphor, Diacetone Alcohol, Ethyl Tosylamide, Benzophenone-1, Citric Acid, Hydrolyzed Wheat Protein, Dimethicone, Calcium Pantothenate, Ci 60725 (Violet 2), Ci 77891 (Titanium Dioxide).
Analysis. Base coat D contains formaldehyde as a nail hardener. Triphenyl phosphate is an endocrine disruptor; most polish brands have removed it from their products. Diacetone alcohol is a flow modifier. Tosylamide/formaldehyde resin is known to cause allergy.
Base Coat E
Butyl Acetate, Ethyl Acetate, Phthalic Anhydride/Glycerin/Glycidyl Decanoate Copolymer, Nitrocellulose, Isopropyl Alcohol, Acetyl Tributyl Citrate, Dimethyl Sulfone, Adipic Acid/Neopentylglycol/Trimellitic Anhydride Copolymer, Biotin. May Contain: Violet 2 (F.I.L. D221743/1)
Analysis: The primary film former in base coat E is nitrocellulose. Phthalic anhydride/glycerin/glycidyl decanoate copolymer and adipic acid/neopentylglycol/trimellitic anhydride copolymer are secondary film formers. Biotin and dimethyl sulfone are present for possible nail benefits.
Base Coat F
Ethyl Acetate, Butyl Acetate, Nitrocellulose, Isopropyl Alcohol, Adipic Acid/Neopentylglycol/trimellitic Anhydride Copolymer, Acetyl Tributyl Citrate, Stearalkonium Bentonite, Stearalkonium Hectorite, Benzophenone-1, Styrene/Acrylates Copolymer.
Analysis: Base coat F has nitrocellulose as primary film former. Adipic acid/neopentylglycol/trimellitic anhydride copolymer and styrene/acrylates copolymer are the secondary film formers. Acetyl trinbutyl citrate is the plasticizer. Stearalkonium bentonite and stearalkonium hectorite are modified clays common in traditional nail polishes to help keep the pigments suspended. Because pigments are not in the base coat, these clays are present to thicken the film.
Base Coat G
Isopropyl Alcohol, Water, Polyurethane.
Analysis: Base coat G is the simplest of all nail polish base coats whose sole purpose is to keep the polish on the natural nails and deliver long-wear to the polish. Water and isopropyl alcohol are the carrier solvents. There is only one film former, and it is a polyurethane. This base coat is nitrocellulose-free and, therefore, will not turn nails yellow. It should only be used with nitrocellulose-free polishes. The nitric acid from the nitrocellulose present in traditional nail polishes that turns natural nails yellow is a small molecule and passes through base coat G.
Know Ingredients
As you can see, base coats vary greatly in composition, attribute, performance and result. It always pays to know your product ingredients, as the success of your service and your clients’ satisfaction may one day depend on it!
References
- www.nailpro.com/health/article/22249191/vb-cosmetics-dazzle-dry-nail-lacquer-the-real-cause-of-natural-nails-turning-yellow
- www.contactdermatitisinstitute.com/pdfs/allergens/Tosylamide%20%EF%80%A2%20formaldehyde%20resin.pdf
About the Author:
Vivian Valenty, Ph.D. (@nailpolishdoc), is the founder and president of VB Cosmetics, the creator and manufacturer of Dazzle Dry. She is also a member of Nailpro’s 2022 advisory board. She obtained her doctorate in chemistry from Penn State University, and for the past 33 years, has been creating products for the professional nail industry.
