Exilva MFC in high alcohol based products such as hand sanitisers

Hydroalcoholic hand sanitisers are the best option to for hand hygiene when soap and water are not accessible. They are currently among the most used and needed products.

If you are considering to formulate a hand sanitiser, read about how you can use Exilva microfibrillated cellulose, a bio-based material, to structure and thicken your formulations and provide a non-tacky feel.

From the Centers for Disease Control and prevention (CDC) website:

"Hand Hygiene is best practiced by washing hands with soap and water. This act reduces the amount of all types of germs and chemicals on hands. If soap and water are not available, using a hand sanitizer with a final concentration of at least 60% ethanol or 70% isopropyl alcohol inactivates viruses that are genetically related to, and with similar physical properties as, the COVID-19 virus."

Let's discuss the possibility of using Exilva microfibrillated cellulose with high concentrations of alcohols in products such as hand sanitisers.

 

Increased need for thickeners, rheology additives, structuring agents for hand sanitiser:

Due to the global situation and the above recommendations, the need for, and the use of hand sanitisers has increased in a way that was likely unforeseen or in 2019. Therefore, there exists high need for quick availability and supply of not only the alcohols, but also additives used in these formulations as rheology and structuring agents.

To demonstrate that Borregaard’s bio-based additives can be part of the solution if and when needed, we have conducted a study to show that it’s possible to use Exilva, a bio-based cellulose fibrillar structuring agent to control the flow and rheology highly concentrated alcohol formulations such as hand sanitisers.

Hand sanitisers are traditionally and most often a clear transparent gel. Not all common rheology additives and structuring agents are soluble or dispersible in high concentration of solvents. In hand sanitisers, rheology additives such as acrylates and cellulose derivatives are used to make these products gel-like. 

 

What are the features of a hand sanitiser formulated with an innovative and high performance material such as Exilva?

Exilva can be used to thicken and structure formulations containing very high concentrations of up to 90 wt% of ethanol and isopropanol.

Below is an example of a formulation containing Exilva MFC:

Ingredients Weight Percentage Function
Water 14.50 Solvent
Glycerol 5.00 Denaturant, Humectant
Exilva MFC ** 0.50 Rheology additive
Alcohol * 80.00 Active

* Alcohols tested: Ethanol and Isopropanol
** Concentration based on dry cellulose fibril content 

The addition order and dispersion method used are important when looking for optimal performance of Exilva.

Appearance:

The resulting hydroalcoholic formulations (both with ethanol and isopropanol) are homogeneous, non-transparent and opaque. The non-soluble nature of the entangled cellulose fibrils in Exilva is responsible both for the structuring of high levels of alcohol and giving an opaque appearance.

Skin feel:

Exilva is a non-greasy, non-tacky rheology additive improving skin feel of the end formulation resulting in a non-sticky product. Read more about the use of cellulose fibrils in cosmetics here

Shear thinning:

Due to the extreme shear thinning behaviour of the fibrils, hand sanitiser containing Exilva sprays as a nice mist with non-dripping effect on vertical surfaces.

Brookfield viscosity:

The measured Brookfield viscosity of this alcohol containing formulation is 1 200 – 1 300 mPas (Spindle V-72 ; 10rpm for 5 minutes). The viscosity can be adjusted by adjusting the concentration of Exilva MFC used.

Keep in mind that due to the extreme shear thinning behavior of Exilva, Brookfield viscosity values measured under a given shear are much lower than the viscosity at rest.

 

Yes, you can!

As a conclusion, it is definitely possible to use Exilva MFC as a rheology and structuring agent for high concentrations of alcohol and in hand sanitisers. Exilva imparts a very high viscosity at rest to the formulation and allows for good flow properties and the possibility to spray.

Bio-based Exilva is a rheology additive different from what is traditionally used for the above-mentioned applications. The end product might look different, but will be sprayable and non-tacky, and will probably lower the carbon footprint of the end formulation.

Order a free sample to test or contact us for more detailed information on the use of Exilva with alcohols and in hand sanitisers.