The science and art of formulating emulsions is the ability to bring two or three incompatible materials (lipophilic, hydrophilic, oleaginous, or solid) together into a quasi-stable system that keeps the ingredients intermingled even though they have little desire to remain so. The literature and internet abound with reviews, training guides and videos explaining how to best make stable emulsions. And recently, it seems, the focus on natural or multifunctional ingredients is driving even further innovation in emulsion technology.

At the most fundamental level, emulsions are colloidal systems. They are mixtures of one kind of particle or fluid within a continuous phase which forms the bulk of the emulsion stabilized by a surface active (surfactant) or polymeric rheology modifier.^1,2 When cosmetic chemists speak about emulsions, they are usually referring to mixtures of either oil-in-water (O/W with water as the continuous phase) or water-in-oil (W/O with oil as the continuous phase). Color cosmetics are also colloidal systems that involve stabilizing pigments in solid (lipstick) or semi-solid or fluid states (foundation). People can spend many years of their lives learning about how to make stable colloidal systems and companies find such knowledgeable individuals to be invaluable in their drive for innovation and products.

Wax dispersions are a subset of the greater colloidal system universe, but they are very important in several industries.³ Waxes are defined by Bouvy as being of three critical aspects:

• Solid at 20oC but varying in consistency from soft and plastic to hard and brittle;
• Having a melting point of at least 40oC without decomposing (important for differentiating waxes from oils and natural resins); and
• A relatively low viscosity at temperatures above the melting point.

In cosmetics, wax emulsions are found in nearly every kind of product category from low viscosity sprayable emulsions to solid stick products like lipsticks. Usually, wax emulsions are made through a somewhat laborious process that involves melting the wax and subsequently dispersing and stabilizing the wax particles in water (or possibly silicone, but for the purposes of this article, we will focus principally on wax-in-water emulsions). Waxes impart unique feel benefits to formulations not found in other non-solidifying lipids such as fatty acids or esters. 

In 2010, Jeen International introduced a new concept in cold-water dispersible wax technologies called Jeesperse Cold Process Waxes (CPW) and Jeesperse Instant Cold Emulsion Technology (ICE-T).⁴ Since the inception of these unique emulsion concepts, Jeen International has filed and been granted patents covering the composition, methods and use of these dispersible waxes. Jeen has begun to expand its portfolio of innovative dispersible waxes and this article will provide an update of some of these new and exciting areas of development.

Wax Dispersion Technologies
As noted earlier, waxes are solids at room temperature. As such, colloidal systems comprised of waxes in water exist not directly as emulsions but instead as dispersions of wax particles suspended in aqueous solutions. Historically, wax dispersions are manufactured by melting waxes to their liquid form and then via standard emulsification technologies, blending the liquified waxes into hot water and employing various rheology-control technologies to maintain the wax particles in a quasi-stable suspension of wax-in-water. As these dispersions cool, the liquified waxes will begin to re-solidify into small suspended particles now maintained in what typically looks like a milky liquid or thickened cream. The final texture and rheology of the wax dispersion will depend on several factors but principally will be dependent on the selection of the rheology control technology that the formulator employs.

Jeen recognized that the manufacture of wax dispersions is laborious and, in 2010, introduced the patented Jeesperse dispersion technologies.⁴ These early introductions employed low melting polyethylene waxes that could be easily dispersed into colloids using various anionic and cationic polymeric rheology modifiers. Once formed, the wax dispersions could be further modified as required by adding oils, frequently without the need for the addition of secondary emulsifiers. Most strategically, the Jeesperse CPW technologies enabled formulators to build luxurious creams and lotions with various levels of viscosity and rheology by simply mixing the powdered Jeesperse CPW waxes into cold water with vigorous stirring. Morever, formulators found that in standard emulsions, addition of the Jeesperse waxes to emulsions could improve the tactility or stability of existing emulsions without the need to re-heat the primary emulsion. Waxes with melting points  exceeding 120oC could be converted to Jeesperse CPW powdered ingredients and formulators would find they could disperse such high melting waxes easily into cold water with just vigorous stirring. Simplification of the dispersion formation in this fashion allowed formulators to move away from the need to use multiple tanks and extensive heating to much more simplified processing that entailed simply mixing the Jeesperse CPW powders into cold water and allowing the powders to hydrate and disperse with stirring to create creams and lotions (Figure 1a and 1b). 

Evolution of Wax Dispersions
As previously noted, early iterations of the Jeesperse CPW technologies relied solely on the stabilizing strength of the polymeric rheology modifier to stabilize the wax colloids. However, it became apparent that manufacturers needed more robust systems that included more traditional surface-active emulsification technologies and waxes that were different that simple polyethylene. The development of the Jeesperse ICE-T technology was the solution to this challenge and with these ingredients, Jeen was able to provide both polymeric dispersions and emulsifier-based wax dispersions in cold water processable systems.

Jeesperse ICE-T technologies employ more traditional emulsifiers such as cetearyl alcohol, stearic acid and ceteareth-20, in combination with rheology-modifying polymers to create very stable emulsified wax dispersions. The portfolio of waxes expanded to include various synthetic and natural waxes that, by their nature, require heating and melting to work with.

By employing the manufacturing know-how developed to create the original Jeesperse CPW powders, Jeen was able to further expand product offerings to include combinations of polymeric rheology control agents and standard emulsification technologies into easy-to-use powders. Like their CPW precursors, the ICE-T powders can be quickly and easily dispersed into cold water, with stirring as the only form of energy applied to the formulation. Stirring energy is critical for the systems as they still require powder dispersion good enough to allow hydration of the rheology control polymers and the entrained emulsifiers. But, they are very simple to use, and formulators have found that inclusion of the Jeesperse CPW or Jeesperse ICE-T technologies into their formulating arsenal can help to significantly speed up processing of O/W creams, lotions and sprays.

The Move to Natural
The fact that the cosmetic industry has been shifting toward more naturally-sourced ingredients is no surprise to anyone reading this article. Consumers speak to finished goods manufacturers with their wallets and they are telling manufacturers that they don’t want to read ingredient labels that contain ingredients they don’t appreciate. Unfortunately, sometimes the consumers can take these desires to an extreme as in, for example, claims such as products being  “chemical free.” Everything is a chemical. Water is a chemical. Nonetheless, one may find products on the shelf that have in the small print “chemical free” as a label claim. To this we would suggest: Caveat emptor.

But, the trend toward using ingredients that are naturally- and, more importantly, sustainably-sourced is important and an exciting opportunity for raw material manufacturers to look for innovation and create new ingredients that meet these needs. Consumers prefer naturally-sourced ingredients which do not carry intimidating INCI names. 

Jeen recognizes this trend and has expanded its wax dispersion technologies with two interesting products which are dispersion technologies that are based on over 95% naturally-sourced ingredients. These powders are Jeesperse OptiDerm for skin barrier repair and Jeesperse OptiTress for hair repair and treatment. In both cases, the polymeric rheology modifier has been sourced from natural hydrocolloids like dihydroxyxanthan or guar gum isolated from fermentation or plant sources, respectively and natural emulsifiers such as cetearyl glucoside and glyceryl stearate isolated or manufactured from naturally-sourced fatty acids and alcohols. 

Jeesperse OptiDerm was designed to allow rapid dispersion of a synthetic human skin ceramide mimic called hydroxypropyl bispalmitamide. In this way, the Jeesperse technology has been further refined to include over 95% naturally-sourced ingredients and it begins to now present the opportunity to deliver difficult to disperse actives like ceramides.

Jeesperse OptiTress was developed to offer hair care formulators a very rapid way to make a hair treatment and conditioner that brings in various oils like coconut and Argania oil in combination with a synthetic quaternary conditioner, behentrimonium chloride, into a cold-processable wax powder that is easy to use and dispersible into cold water. Like Jeesperse OptiDerm, Jeesperse OptiTress is more than 95% naturally-derived.

The Future of Wax Dispersions
Since its launch in 2010, Jeen’s cold processable wax dispersion technologies continue to evolve and grow as the company gains greater understanding of consumers’ needs and desires. What started as a way to help formulators speed up the difficult process of getting waxes into colloidal dispersions has evolved to become an effective means of delivering unique hair and skin care actives. With the movement of the industry to more natural systems, the Jeesperse technologies have evolved in step to now have systems that employ naturally-sourced ingredients. But, the systems that use the synthetic polymeric rheology modifiers continue to offer significant opportunities for formulators to accelerate their formulating processes with these easy-to-use powders. 

The company will continue to examine unique waxes, rheology modifiers, and emulsifiers that build on the patented success of these innovative products. As noted, the ability to also combine skin and hair care actives into the wax dispersion begins to expand the potential for the products to become a technology designed for delivery of hair and skin care actives in easily processable powders.       

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More information: Jeen International, Tel: 800-771-JEEN (5336), Email: info@jeen.com; Website: www.jeen.com.

References

1. Goddard ED. Polymer/Surfactant Interaction: Manifestations, Methods and Mechanisms. In: Principals of Polymer Science and Technology in Cosmetics and Personal Care.  Ed: Goddard ED and Gruber JV. Francis Taylor, NY 1999, pgs 113-180.
2. Tadros TF. Polymeric Surfactants: Stabilization of Emulsions and Dispersions. In: Principals of Polymer Science and Technology in Cosmetics and Personal Care.  Ed: Goddard ED and Gruber JV. Francis Taylor, NY 1999, pgs 73-112.
3. Bouvy A. The Use of Wax Emulsions in Coatings and Inks. Paint Coat Ind. 2005.
4. Mateu J. A Game Changing Emulsion Technology. Happi 2010.