COSMETICS ADDITIVES

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EMULSIFIERS IN COSMETICS

 

Are you also interested in the production of cosmetic products consisting of emulsions? In that case, you cannot do without an emulsifier. In cosmetics, emulsions are most often formed in the production of creams, body milks, balms and ointments, products that contain both water and oil.

 

Oil and water ingredients are normally immiscible with each other under normal conditions. Emulsifiers are used to make them into one "compact mass". These are substances that ensure the reduction of surface tension and the dispersion of droplets of one phase into the other. You can achieve the same thing by simply mixing, but you will have noticed that almost immediately the water and oil phases separate again. the role of emulsifiers is thus also to slow down the time it takes for the two phases to separate again, thus giving you a stable emulsion. This happens because each emulsifier molecule contains two parts - one that binds to the water and one that binds to the oil. With the right choice of emulsifier for your beauty product, you will achieve a stable and permanent emulsion.

 

TYPES OF EMULSIONS

 

Knowing the type of your emulsion is important to choosing the right emulsifier. We distinguish between emulsions:

 

- O/W - oil in water, where the oil is dispersed in the water. An example is a body lotion or a light lotion. The disadvantage is that due to the higher water content, these emulsions are more easily attacked by microorganisms, but at the same time the water causes a cooling effect on the skin. It is advisable to use O/W emulsifiers in these emulsions, these are usually characterised by the fact that they cause good spreadability of the product and are stable even below 0°C. These include natural emulsifiers such as Cetearyl alcohol, stearic acid, Glyceryl Stearate Citrate, Sucrose Stearate, Montanov, Olivem, Beautyderm, PolyAquol-2W, Xyliance, Plantasens HE20 and others.

 

- W/O - water in oil, when water is dispersed in oil instead. Examples are thicker ointments, balms, night creams and the like. Such emulsions are more difficult to stabilize than O/W and the substances in it must be dispersed into very small droplets. Because of their high oil content, they form a greasier film on the skin; on the other hand, they are more resistant to microbes and water. This type of emulsions requires W/O emulsifiers, their advantage is that they are gentle on the skin.

 

Examples of this type of natural emulsifiers include Glyceryl Sterate SE, lecithin, Polyglyceryl oleate, Glyceryl oleate, Neocare P3R, Polyglyceryl-4-oleate.

 

Emulsifiers can also be classified according to their ionic character. The vast majority of natural emulsifiers are non-ionic. There are anionic exceptions such as Sodium Lauroyl Lactylate. Cationic natural emulsifiers are very rare, their function is fulfilled for example by quats such as BTMS, but these are not classified as natural emulsifiers.

 

TIPS AND TRICKS WHEN WORKING WITH EMULSIFIERS

 

pH of the environment

 

Most emulsifiers work well in the pH range of 4.5 - 6, this is also the most common pH for cosmetics. If you want to work with products outside of these pH values, choose an emulsifier that will work in this range as well.

 

Amount of oil in the product

 

The proportion of oil and fats in the emulsion formulation can also affect the choice of emulsifier. This is because some emulsifiers work better with lower oil content (5-15%) in the product, while others are better suited to higher oil content (25-45%) or intermediate values.

 

Product viscosity

 

The function of emulsifiers also depends on the viscosity of the product. If you want to make very liquid emulsions for atomizers it is advisable to choose emulsifiers designed for this purpose, likewise in the opposite case. At the same time, the viscosity (how thick your product will be) can also be partly influenced by the emulsifier, by changing the ratio of the oil phase to the emulsifier, which can thicken the product. Adding thickeners appropriate to the emulsifier or changing the ratio of the aqueous phase to the oil phase in the product can have a similar effect.

 

Nature of the oil phase

 

Not all substances that are part of the oil phase will behave the same when a given emulsifier is used. In fact, some emulsifiers work better with paraffins and silicone oils (these are not approved for natural cosmetics), others with triacylglycerols (common vegetable oils).

 

Emulsifiers for cold and hot processes

 

Most emulsifiers on the market are designed for use in hot cosmetic manufacturing. The warm process consists of heating both the aqueous and oil phases of the emulsion to a temperature determined either by the stability point of one of the raw materials or by a suitable temperature for the emulsifier, and then mixing the two phases. During cooling, it is necessary to stir the mixture, preferably with a mixer, to improve the dispersion of droplets of one phase into the other and to form a stable emulsion. There are also emulsifiers for cold processes that do not require heating to a higher temperature to melt and mix. This is useful if you want to save energy to heat the phases, but it will also make it easier to work with heat sensitive ingredients.

 

Effect on product colour and aroma

 

Some emulsifiers may affect the coloration or odor of the product. If you want snow-white creams, avoid using emulsifiers with too strong a yellow coloration.

 

Emulsifier concentration

 

When describing individual emulsifiers, you will usually find information directly from the manufacturer on what percentage of emulsifier is appropriate to use in a given product. Some emulsifiers are already a mixture of different substances, so it is sufficient to use them in smaller quantities. Others must be used in a higher concentration.

 

Compatibility with other ingredients

 

When selecting the appropriate emulsifier, also look at the other ingredients in the recipe. This is because some substances destabilize emulsions and it is necessary to use co-emulsifiers. Other ingredients reduce the viscosity, which is compensated by stabilizers.

 

Stabilizers and co-emulsifiers

 

Sometimes it is not sufficient to use an emulsifier alone and the formulation calls for the use of a co-emulsifier to increase emulsifying ability, e.g. these are fatty alcohols or esters. Alternatively, the product requires stabilizers beneficial to greater emulsion stability.

 

Texture of the final product

 

Emulsifiers also affect the texture of cosmetic formulations. This is influenced by very many factors, so it is impossible to say reliably in advance how a particular emulsifier will react in conjunction with other ingredients in a recipe and it is usually necessary to check this practically.

 

MOST COMMON EMULSIFIERS USED 

 

- Olivem 1000

 

This is a natural O/W emulsifier, suitable for a wide pH range of 3-12, added to the oil phase at 75°C. Its properties are improved by the addition of 0.2% xanthan gum. Co-emulsifiers such as cetyl and cetearyl alcohols can also be used with it to thicken the product.INCI: Cetearyl Olivate & Sorbitan Olivate. It is suitable for the production of creams and thicker types of emulsions.

 

- Neocare P3R

 

This is a natural W/O emulsifier suitable for creating very low viscosity (liquid) emulsions. It is suitable for both hot and cold process production, dissolving in the oil phase. However, it requires stabilization with electrolytes - MgSO4, NaCl and others. INCI: Polyglyceryl-3 Polyricinoleate, Polyglyceryl-3 Ricinoleate

 

- Beautyderm K10

 

Analternative to the more expensive Olivem 1000 is Beautyderm. It is a natural O/W emulsifier, soluble in the oil phase at 70°C, pH of use 2.5-7. INCI: Sorbitan Olivate, Cetearyl Glucoside, Cetearyl Alcohol. You will appreciate it in the production of creams or body milks, as well as other products.

 

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Another representative from the natural non-ionic W/O emulsifier family is lecithin. For cosmetic use, it is most commonly obtained from soybeans or sunflowers and is soluble in the oil phase. Lecithin allows the formation of an emulsion but does not thicken the product, so it must be combined with co-emulsifiers such as cetyl or cetearyl alcohol or the thickener xanthan gum. It has the advantage of being gentle on the skin and moisturising, and is used in low concentrations of up to 5%.

 

There are no shortage of factors to consider when choosing an emulsifier, but this is where your creativity comes into play. In general, the more ingredients your product contains, the more difficult it can be to choose the appropriate emulsifier, but it is not impossible. It just takes a little experimentation and over time you will find out for yourself which emulsifier suits you best.