Since the COVID-19 pandemic began Silverson Machines has received several enquires as to whether their mixing equipment can be used for this application.
In response to these enquires the company has produced a video and application report detailing how Silverson mixers are used for this application, highlighting the advantages high shear mixers offer when compared to conventional agitators.
There are a number of active ingredients used in hand sanitizers, but the most effective sanitising products are based on alcohol, usually isopropyl or ethyl alcohol. Typically the alcohol content is between 60 and 95%.
This is usually blended with an aqueous dispersion of carbomers such as Carbopol to provide the gelling effect.
One of the key steps in the manufacture of hand sanitisers is the preparation of the aqueous phase. Obtaining an agglomerate-free dispersion is essential to ensure a clear, bright gel after neutralisation.
Low density powders such as Carbopol can be difficult to incorporate into liquids with a conventional agitator, and this can lead to dusting problems and aeration.
Aeration must be minimised as it is difficult to get air out of the product once the gel has been formed.
When using conventional mixing equipment to blend the phases together stratification can occur, particularly where there is a wide difference in the viscosity of the phases. This leads to long mixing times, poor consistency and variation from batch to batch.
A high shear Silverson mixer can overcome the challenges faced by conventional mixing equipment and Silverson offer a range of mixers for this application.
The high shear action of a Silverson mixer will rapidly wet out and disperse the powder, resulting in an agglomerate-free solution in a short mixing cycle and because the turbulence is all below the surface, aeration is minimised.
Silverson has already supplied several machines to customers for the manufacture of hand sanitiser solutions.
Laboratory scale and Pilot scale mixers have already been ordered for this application and a special unit normally used for production of sauces want sent to Malaysia for the manufacture of hand sanitisers, assisting in the attempt to reduce transmission of the virus and showing the flexibility of Silverson’s mixing equipment.
For larger batches, Silverson In-Line mixers offer completely aeration-free processing as the mixer, pipework and vessel form a closed system.
The Silverson Flashmix can also be used for this application; mixing operations can be carried out in a closed system eliminating aeration and powder can be added at a controlled rate minimising dusting problems.
Silverson also offer the advantage of being able to provide mixers suitable for operation in explosion proof zones.
For more information or to discuss your application please visit: www.silverson.co.uk or contact us at: sales@silverson.co.uk.
