One problem in many skin care applications is how to combine a good sustainability profile with light and attractive skin feel. The answer? AAK believe eco-design and esters like its innovative Lipex Shea Light that combine high functionality with light skin feel and a good sustainability profile are a good start.
The global trend in skin care is to make formulations lighter, especially body lotions and facial care products. New markets and new demands from consumers are driving this trend,causing formulators to search for novelties combining good performance in terms of sensory properties with a good safety profile.
There is also a search for ways to design more sustainable formulations. Synthetic ingredients are replaced by renewable alternatives when possible.
Traceability of raw materials is an increasing concern as consumers become more and more aware of environmental and social development issues.
Eco-design the new direction product development
In order to ensure a sustainable future, new developments in raw materials for personal care must today consider eco-design. By anticipating sustainability aspects of new ingredi¬ents already during the design stage, costly mistakes in the future can be avoided. An ingredient or a formula¬tion that contributes to better care for the environment and enables socio-economic development is future-proof.
One example of applying eco-design principles in new product development is considering alternative raw materials at an early stage. Esters are attractive ingredients for personal care, and many are available on the market. To make an ester requires a fatty acid base and an alcohol. Traditionally synthetic alcohols such as isopropyl alcohol and isooctanol are used for cosmetic esters, but as these are non-renewable, we chose to look for alternatives from agricultural sources.
Ethanol was the best choice due to its easy availability and low en¬vironmental impact. For the fatty acid component, shea butter was the ob¬vious choice partly for its importance to the social and economical develop¬ment of West Africa, but also due to its suitable fatty acid composition (high content of oleic and stearic acid).
A crucial part of eco-design is the selection of processing conditions. The conventional direct esterification of a fatty acid with an alcohol requires a high input of energy and the use of environmentally inferior catalysts. In the case of Lipex SheaLight, we use lower temperatures, shorter proces¬sing times and biodegradable cata¬lysts, lowering the total energy use and consequently the greenhouse gas footprint.
Is there a need for another shea ingredient?
Traditional semi-solid shea butters are considered highly moisturising but have a heavy skin feel, which is not in line with current trends. The intro¬duction of Lipex 205 (liquid shea but¬ter) and Lipex Shea WM (shea butter oleyl esters) made it possible to start formulating for lighter skin feel with high shea butter content, but there is still room for improvement. Lipex SheaLight bridges the gap between existing synthetic esters with light skin feel and traditional shea butters.
Unique sensory profile
The sensory properties of Lipex SheaLight were evaluated using a trained sensory panel according to standard procedures. The skin feel 20 minutes after application showed significant differences between the emollients, with Lipex SheaLight being less greasy and more powdery com¬pared to the reference emollients. The results show that Lipex SheaLight has the desired sensory profile for modern skin care creams and lotions, which is also confirmed in formulation tests.
Emollients with light skin feel often show high spreadability combined with low viscosity at body temperature. Lipex SheaLight has a viscosity of 6 cP at 40°C, which is very low compared liquid shea butter (49 cP) and oleyl esters (19 cP).
This enables the formulation of easy application lotions, even in the form of sprayable emulsions. It also makes it possible to create anydesired texture by combining with emollients having other sensory characters.
The unique composition of shea butter featuring a high concentra¬tion of oleic and stearic acid is also reflected in the melting and solidifica¬tion behaviour of Lipex SheaLight. The melting point is close to 18°C due to the content of stearic acid esters. This makes Lipex SheaLight suitable even for cold processed creams and lotions, indicating its usefulness in sustainable cosmetic formulations.
Safe ingredients are a must
There is a strong focus on the safety of cosmetic products and the ingredi¬ents used to formulate them. Esters are generally regarded as safe ingredients for cosmetics due to their origin in fatty acids and their simila¬rity to skin lipids. The safety of Lipex SheaLight has been confirmed in HET-CAM tests for eye and mucous membrane irritation, and in Human Repeated Insult Patch Tests for skin irritancy and sensitisation potential. It is also important to evaluate envi¬ronmental toxicity, where the first step is to ensure ready biodegradation. Lipex SheaLight was found to be readily biodegradable with no accumulation of breakdown products in the environment.
A versatile ingredient forall types of skin care
Lipex SheaLight is an ideal emollient for any type of body lotion, especially when combined with moisturising components such as Lipex Shea or Lipex Sheasoft. It mixes well with dif¬ferent types of actives for facial care creams and serums, making it easy to formulate products for sensitive and aging skin. Lipex SheaLight can be used alone or in combination with other esters, vegetable oils, silicone oils and synthetic emollients when for¬mulating everyday skin care products. It is also a good base for sustainable cosmetic formulations where its light skin feel can be used to improve the aesthetics. Typical use concentrations range between 5-15% in oil-in-water emulsions.
In addition, the low viscosity, high polarity and good solubilising proper¬ties of Lipex SheaLight make it a good base for make-up removal and emul¬sion type facial cleansers. In this case a more moisturising formulation is obtained by combining the shea butter esters with the liquid shea butter.
So, now that there is an ester that answers the need for both light skin feel and good sustainability profile, the stage is set for creating new, safe and more sustainable formulations that consumers are looking for.
