In this cosmetic formulation series we will go through the various cosmetic & personal care formula types and describe what they are, what raw materials are in them and how they are manufactured.
Since this is a cosmetic science blog geared to introduce people to the topics of formulating, we thought it would be helpful to have a series introducing the absolute basics of formulating. And since I spent many years as a hair care formulator, the easiest to start off with is Shampoos.
What is a shampoo
Shampoos are cleaning formulations made up primarily of chemicals called surfactants that have the ability to surround oily materials on surfaces and allow them to be rinsed away by water. While there are numerous types of shampoos the majority are low viscosity, solution formulas delivered from a plastic bottle. Often they are marketed towards different hair types or conditions.
Shampoo raw materials
When you begin formulating a shampoo you first figure out what characteristics you want. This would include things like how thick it will be, the color, and fragrance. It also includes performance things like how well it cleans, what the foam looks and feels like and how irritating it will be. Often consumer testing is employed to help with determining these characteristics.
The basic ingredients in a shampoo formulation is as follows.
Water. The primary ingredient in all shampoos, it makes up about 70 to 80% of the entire formula. It helps dilute the detergents, makes the formula easier to spread and reduces irritation. It also keeps the formula inexpensive.
Detergents. The next most abundant ingredients in a shampoo. These surfactants are the primary cleansing ingredients and make up about 10% – 15% of the formula. They are derived from natural fatty acids or petroleum derivatives. Common primary detergents include Ammonium Lauryl Sulfate, Sodium Lauryl Sulfate and Sodium Laureth Sulfate.
Foam Boosters. Other types of surfactants are added to shampoos to improve the foaming characteristics of the formulation. These compounds usually betaines or alkanolamides, help increase the amount of foam and the size of the bubbles. Like primary detergents, they are also derived from fatty acids and have both water soluble and oil soluble characteristics. Typical materials include Lauramide DEA or Cocamidopropyl Betaine.
Thickeners. To some extent the secondary detergents make shampoo formulations thicker. Simply adding salt can also increase shampoo thickness. However, other materials are also used to increase the viscosity such as Methylcellulose which is a cellulosic polymer or Carbomer.
Conditioning agents. Some materials are added to shampoos to offset the harsh effect of surfactants. Typical conditioning agents include polymers, silicones, and quaternary agents. These ingredients are left on the hair surface after rinsing and modify characteristics such as feel, softness, combability, and static charge. Shampoos that specifically feature conditioning as a benefit are called 2-in-1 shampoos because they clean and condition hair in the same step. Examples of conditioning agents include Guar Hydroxypropyltrimonium Chloride which is a polymer, Dimethicone which is a silicone, and Quaternium 80, a quaternary agent.
Preservatives. Any formula that contains water holds the potential to be contaminated by bacteria and other microbes. For this reason preservatives are added to prevent such growth. Two of the most common preservatives used in shampoos are DMDM Hydantoin and Methylparaben.
Other ingredients. A variety of other compounds are included in shampoos if desired. Dyes for changing color, fragrances for changing the odor, pH adjustment ingredients, chelating agents, opacifying ingredients, and more. Frequently, story ingredients are included so marketers will have something to talk about. This includes things like vitamins, proteins, and herbal extracts which are not normally expected to have any impact on the final product performance. Dandruff shampoos will include a drug active ingredient like zinc pyrithione.
Shampoo Manufacturing Process
The manufacturing process can be broken down into two steps. First a large batch of shampoo is made and then the batch is filled into the packaging.
Compounding. The process of any large scale cosmetic production is called compounding. All the ingredients are mixed together in large, stainless steel tanks (3000 gallons or more) by workers known as compounders. The raw materials, which are typically provided in drums as large as 55 gallons or in 50 lb bags, are poured into the batch tank and thoroughly mixed. The order and temperatures are determined by the formulating chemist. Some ingredients like water or the primary detergents are pumped and metered directly into the batch tank. A computer interface is often used to control mixing speed and temperature. Depending on the size and type of shampoo, making a 3000 gallon batch can take any where from 1 to 4 hours.
Quality Control check. After a batch is approved by the QC department, it is pumped out of the main batch tank into a holding tank where it can be stored until the filling lines are ready. From the holding tank it gets pumped into a filler which is positioned on the filling line..
Filling. The filling line is just a long conveyor belt. At the start of the filling line, empty bottles are put into a hopper. The bottles are physically manipulated by a machine until they are upright and correctly oriented. They move along the conveyor belt to the filling carousel which holds the shampoo.
The filling carousel is made up of a series of piston filling heads that are calibrated to deliver exactly the correct amount of shampoo into the bottles. As the bottles move through this section of the filling line, they are automatically filled with shampoo.
From here the bottles move to capping machine where caps are put on. This can also be done by workers depending on the speed of the filling line. Next, labels are applied, then the bottles are moved to a sorting machine that puts them into boxes.
This video shows an example of a shampoo being filled.
Do you have any questions about shampoo formulas? Leave a comment below.