FRUGAL INNOVATION
The beauty and cost-saving benefits of inverse emulsions For the longest time, w/o emulsions were reserved for use in sunscreens, waterproof makeup and nappy (barrier) creams. Yet over the years, emulsion technology has evolved widening the range of applications for emulsions to almost all personal care products. Jacques Strydom, technical manager for personal care and home care at AECI Specialty Chemicals explains the history behind the technology and how the application focus has changed.
I
T’S IMPORTANT TO understand the main
This begs the question, why are the majority
difference between water-in-oil (w/o)
of personal care creams o/w, which is the
phase content increases the viscosity of the
and oil-in-water (o/w) emulsions. Water
opposite type of emulsion?
final emulsion. Thus, oil phases in the order of
and oil are not miscible with each other, so
In w/o emulsions, increasing the dispersed
10% to 15% yield thick creams, while oil phases
emulsifiers are needed to mix the two parts
SELECTING W/O EMULSIFIERS
in the range of 18% to 35% yield lower viscosity
and create a stable end-product.
AND EMOLLIENTS
lotions. The other advantage of w/o is that
In the past, w/o emulsions were perceived
the viscosity of the oil phase is proportional
In colloidal science, the ‘inside’ phase is called the dispersed phase while the ‘outside’
as sticky, greasy, heavy, hard to stabilise and
phase is referred to as the continuous phase.
expensive. However, scientific advances have
In a w/o emulsion, the water is the dispersed
addressed and counteracted these issues
phase and the oil, the continuous phase. W/o
over time. It is now possible to easily produce
offers a number of practical advantages,
w/o emulsions that are cost-effective, easy
because the oil is on the “outside”. For
to stabilise, fast absorbing, feel light on skin
example, the end-product feels oily to the
(where required), and are non-tacky. These
touch – this is commonly experienced with
factors are addressed by two main components
sunscreens. The characteristic enables water
of the formulation, being the choice of
resistance, which is why w/o is the preferred
emulsifier and the selection of emollients.
emulsion type for sunscreens, waterproof
AECI Specialty Chemicals has a solution
Because these emulsions can be designed with such large quantities of oil, makes them perfect for certain hair care products to the final emulsion viscosity, due to the oil phase being the continuous phase. This means
for both of these ingredient types. Its easy-
that adding cosmetic waxes, butters and even
to-use w/o emulsifier base is supplied in a
petrolatum, will significantly alter the structure
so w/o emulsions are great for problematic
viscous liquid format and is used at very low
of the emulsion, allowing applications like
skin, prone to psoriasis, eczema and dryness.
dosages between 1.8% and 3%.
beauty balms and body butters.
makeup and barrier creams. The lipid barrier also locks in moisture,
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QUARTER 4 2021 // P&C AFRICA
