PLASTICS INDUSTRY
Aerosol Spray Development (from Lab to Shelf) Aerosol Spray is a product which by application creates mostly the form of Aerosol (generally fine particles dispersed into the air ( i.e. Hairspray, Body Spray, Waterproof Spray); Foam (i.e. Shaving Foam, Hair Mousse, Foam Cleaners); Jet (i.e. Brake Cleaner); Gel (i.e. Shaving Gel, Shower Gel)
Today, the vast majority of Aerosol sprays are filled by so called “one-chamber” filling technology, where Concentrate (bulk) is mixed with the Filling Medium (propellant) – i.e. Hairsprays, Body Sprays, Waterproof Sprays, etc. Filling Medium in today’s Aerosol sprays are mostly mixtures of n-butane/i-butane/ propane or dimethylether, Carbon Dioxide, Nitrogen, Compressed Air. Less often used are HFC hydrocarbons and nitrous oxide. The other, most commonly used Aerosol spray technology is so called “two-chamber” filling technology. This advanced technology is based on separation of Concentrate and The Filling Medium. Such technology is often called BAG-ON-VALVE or BAG-IN-CAN, where the concentrate is filled in one step into the bag, attached either to the valve or to the can.The Filling Medium is filled outside the bag, into the aerosol can. During | 42
Aerosol spray is composed with three basic parts: Primary Packaging (can, valve, actuator), Concentrate and Filling Medium. During development of Aerosol spray, R&D must consider all three parts at once in order to achieve the desired product, application form and product characteristics. The valid legislation, customer’s marketing requirements (application type, claims) and available production technology must be considered as well. Based on the knowledge of physical-chemical property of concentrate and together with customer’s requirements, the R&D technician searches and tests the most optimal valve, actuator and can configuration. Final application form and spray characteristics are also influenced with selected Filling Media and at last also
with the ratio between the Concentrate and the Filling Media. Each newly developed Aerosol product has to run stability and compatibility tests, where selected formulation, aerosol can, valve and actuator are tested during selected time. Very often, different options of the above are tested, in different temperatures and in different positions in order to simulate the end consumer’s use of the product. Focus of these tests is on the reaction/compatibility of the Concentrate with the Filling Media and selected packaging material. Also spray characteristics are very important to evaluate from the consumer’s point of view. Often formulation incompatibility, fragrance malodor, corrosion, valve plugging or product leaking is detected during these stability and compatibility tests. R&D then has to start all over again until satisfactory combination of formulation and primary packaging is found and the Aerosol product's safety and functionality may be guaranteed during its shelf life. Martin Surynek Jiri Safer
Photo: pixabay.com
the application by the end user, the compressed Filling Medium is squeezing the bag inside the can. The advantage of this “two-chamber” filling technology is filling such concentrates which are less compatible with the filling medium or with the aerosol can itself.
