Understanding Emulsions and Emulsifiers (Brief Overview)
An emulsion is a mixture of water based and oil based ingredients thatare bonded together by an emulsifier.
An emulsifier is a substance or combination of substances that createthe emulsion bond.
Types of Emulsions
Water in Oil W/O - in this type of emulsion the oil surrounds the water andthe oil touches the skin first. The level of greasiness depends onthe percent of oil vs water in the formula and how much is absorbedinto the skin. An W/O emulsion is made with a choice of oils, waterand the emulsifiers needed to make a full, stable emulsion. If donecorrectly the product will have little to no greasiness.
Oil in Water O/W - in this type of emulsion the water surrounded the oil.This emulsion produces cream and lotions that feel moist, lighter andless greasy. As they are absorbed into the skin there is very littleto no oily residue noted with application. A O/W emulsion needs thecorrect level and type of emulsifier to create a stable and completeemulsion.
Types of Emulsifiers
Emulsifier can range from vegan, organic and natural all the way to syntheticlab created.
They can be sourced from vegetables, animals or chemicals and there are amultitude of both natural, mechanical and chemical extraction methodsas well.
They can be produced or harvested in the USA or imported.
This and much more information is necessary to allow the formulator todetermination which emulsifier is the best choice for a formulation.
The HLB (Hydrophilic-lipophilic balance) of an emulsifier is also veryimportant to help determine how effective it will be for eachformulation. The higher the HLB the greater its emulsifying ability.
Beeswax- This weak emulsifier can be naturally harvested from bees and thenfiltered or it can be produced synthetically. It is used in cosmeticand skin care products as both a thickening agent, emulsifier andhumectant. When used incorrectly in cosmetic formulations, beeswaxcan be heavy, waxy and comedogenic. It also provides the positiveproperties of being and emollient and softening agent toformulations when used correctly. HLB ~ 10-12
Carbomer- This synthetically derived cross-linked polymer of acrylic acid isused an emulsifier, emulsion stabilizer, to adjust viscosity and asa thickening agent. It is often used to create gel likeformulations. HLB ~ 12
Cetyl Alcohol - This emulsifier can be synthetically created or naturallyderived from coconut or other vegetable fatty alcohol. It is anemulsifying wax made by combining fatty alcohols. (see fattyalcohols) It is used in many formulations as an emollient,thickening agent, moisturizer, emulsifier, stabilizer or opacifieras well as a carrying agent for other ingredients. It can beextracted using chemicals or naturally mechanically extracted. HLB ~15
Cetearyl or Cetostearyl Alcohol (used interchangeably) - is a blend of cetylalcohol and stearyl alcohol usually meeting *NF specifications. HLB~ 14-15
Emulsifying Wax (aka E wax) - This is a generic term used for emulsifier blendsand can contain any combination of emulsifiers at whateverproprietary ratios the manufacturer chooses. It can be organic,natural, vegetable sourced or completely synthetic. It is usually awhite waxy solid, but can be creamy or yellow and often looks likesmall dome pellets or beads. It is highly effective in both w/o ando/w formulations. It usually has the characteristics of cetylalcohol combined with the viscosity building effect of stearylalcohol and is a very effective thickener that form extremely stableemulsions in either w/o or o/w preparations. HLB ~ 15
Fatty Alcohols - A fatty alcohol it is an alcohol, which is derived from avegetable or animal fat source. It does not behave like a 'realalcohol' like ethanol and is not drying to the skin. Fatty alcoholsare usually derived from coconut oil or palm oil. Cetyl alcohol isoften made by heating coconut oil with a strong base like Sodiumhydroxide (Lye). This process is the same process that occurs duringsoap making (saponification). The differences between cetyl, stearyland cetostearyl alcohol is very little. Stearyl alcohol has aslightly longer carbon chain than cetyl alcohol. (Cetyl has 16carbons while Stearyl has 18). Cetearyl or Cetostearyl alcohol aresimply a combination of cetyl and stearyl alcohol. HLB ~ 14 +
Lecithin- Lecithin is a weak natural emulsifier containing phospholipids asits major emulsifying component. It is found abundantly in animalsand plants. It can be used in both its liquid or powder form informulations. Lecithin is sourced from plants like soybeans, corn orrapeseed. It can be fractionated or isolated from special componentsof the raw materials or isolated from egg yolks by excluding thephospholipids, which compose about 30% of the egg yolk. Lecithin asan emulsifier can also be difficult to use in formulations. It doesnot have strong emulsification and is often used in combination withbeeswax and borax. Because of its strong odor and dark color itshould not be used at greater than 3% of the total formulation. HLB~ 4
PEG's- PEG's are synthetic emulsifiers and usually contain letters andnumbers. PEG stands for polyethylene glycol and it made fromethylene oxide. These polymers are mixed with various othermolecules to produce a wide variety of products of unique qualities.Polyethylene glycol (PEG) is a water-soluble lubricant sourced frompetroleum and/or mineral sources. HLB ~ 15
Polysorbates- These non-ionic surfactants and emulsifiers are derived from thecombination of fatty alcohols and sorbitol which comes from fruitand berries. They can also be synthetically created. Polysorbatesare oily liquids and they are most often used in cosmetics tosolubilize oils into very high content water based formulations.HLB~ 16-17
Polysorbatesare followed by a number that indicates the fatty acid associatedwith the sorbitol part of the molecule.
PS20 - sorbitan monolaurate derived from Lauric acid (often coconut andpalm oil sourced) and connected to sorbitol
PS40 - sorbitan monopalmitate derived from Palmitic acid (often coconutand palm oil sourced) and connected to sorbitol
PS60 - sorbitan monostearate derived from Stearic acid (often coconutand palm oil sourced) and connected to sorbitol
PS80 - sorbitan monooleate derived from Oleic acid (often coconut andpalm oil sourced) and connected to sorbitol
Stearyl Alcohol - This emulsifier can be synthetically created or naturallyderived from coconut or other vegetable fatty alcohol. It is anemulsifying wax made by combining fatty alcohols. (see fattyalcohols) It is used in many formulations as an emollient,thickening agent, moisturizer, emulsifier, stabilizer or opacifieras well as a carrying agent for other ingredients. It can beextracted using chemicals or naturally mechanically extracted. HLB ~14
*NF - When the ingredient name is often followed by the initials NF,this indicates that it conforms to the specifications of the NationalFormulary. These standards are used by regulatory agencies andmanufacturers to help to ensure that these products are of theappropriate identity, as well as strength, quality, purity, andconsistency.
With all the emusifiers on the market today, it can be very difficult tofigure out the right one(s) for your purpose(s). Finding the rightsupplier of raw materials, one that shares your goals, expectationsand standards is the first step in the right direction to a naturalyou.