Submitted To: - Submitted By: -Mr. Madhab Chakraborty SandeepDeputy Director Roll No. 1116IIP 1st Sem, 27th BatchDelhi IIP, DELHI

What is Aerosols and Aerosol Spray?

An aerosol is a suspension of fine solid particles or liquid droplets in a gas.Example: - Smoke, smog, mist from an aerosol can etc.

Aerosol Spray is a type of dispensing system which creates an aerosol mist of liquid particles. Example : - Spray from deodorant, paints etc.

Timeline Of Aerosol Technology 1929: Invented by Norwegian chemical engineer, Erik Rotheim

1942: Aerosol spray can of insect repellent developed

1947: Aerosol technology introduced in air conditioners, refrigerators and spray cans

1974: Discovered that CFCs deplete ozone layer

1978: Use of CFC propellant banned

1987: The Montreal Protocol signed by 24 countries

1996: CFC propellant production in industrial countries was fully phased out

2005: The ODC methyl bromide phased out

2020: Expect phase out of ODC HCFCs under The Montreal Protocol

Working Principle of Aerosol Can

Components of Aerosol Can Can The Head Space Fluid The Curved Base Valve

1. Can

The pressure inside an aerosol can is 2-8 times higher than that of the atmospheric pressure. So Can is to be very strong to withstand the pressure difference between inside and outside it.

Manufacturing of Can Usually made from thin sheet of steel Coating of another material is done on steel to stop rusting

or reacting with product or the propellant. Usually the coating is Tin, often applied by electroplating,

which turns steel into a metal called Tinplate. Tinplate is wrapped into cylinder that has a top and a bottom

to ensure can is completely leak-proof. Tinplate is also replaced by aluminium can which is made

through a Die so as to make single piece can. Product labelling and printing is done by Offset printing

process. Some aerosol cans are also made from plastic polymers and

glass.

TYPES OF AEROSOL CAN

I. Three Piece Tinplate Aerosol Can

II. Two Piece Aerosol Can

III. Single Piece Aerosol Can

THREE PIECE TINPLATE AEROSOL CAN Most widely used Made by seaming together

three components. The body cylinder which is

welded from pre-printed plate

The cone and dome are made by tinplate are flanged by double seam operation

TWO PIECE AEROSOL CAN Cone and body is

a single piece made from aluminium

Dome is made up of tinplate and is double seamed

SINGLE PIECE AEROSOL CAN Also termed as Monoblocks as made

entirely in one piece from aluminium

2. The Head Space

When the can is filled, there is space left at the top to allow for some of the propellant to remain as gas.

3. Fluid

An aerosol can contains two fluids, one which boils well below room temperature (called the propellant) and the other which boils at much higher temperature (called the product).

The Product

It is the substance which we actually use. It is also called the active ingredient which is

dissolved in propellant using other inert ingredients.

Once sealed inside the can, the product is safe from evaporation and contamination.

The Propellant

It is means of getting the product out of the can.

It is the driving force behind the aerosol can.

There are two types of propellants: Liquefied Propellant Compressed Gas Propellant

Representation of Propellants inside Can

Formulation of Product & Propellant

Sr. No. Product Ratio(Product : Propellant)

1 Space Sprays 20:80

2 Surface Sprays 75:25

3 Shaving Foams 95:05

4 Hair Sprays 70:30

Typical Propellants Being Used Liquefied Petroleum Gas: - These are flammable

and used in most aerosols today including household products.

Di-Methyl Ether: - It is an alternative to LPG and is more commonly used in personal care products and air fresheners.

Chlorofluorocarbons: - CFCs were used very commonly but after the discovery that they depletes ozone layer, their use has been banned. But they are still used in inhalation aerosols, as

used in treatment of asthma.

Non-Soluble Compressed Gas: - They are used in consumer products as an environmental alternative to LPG. Example is nitrogen.

Soluble Compressed Gas: - It is also an alternative to LPG but have very limited use mainly with alcoholic system such as air treatment products, deodorants and personal care products.

 

4. The Curved Base

The unusual curved bottom of aerosol container performs two functions: -

Strength of Can

Ease of Complete Consumption of Product

5. Valve It is a complex little thing fitted at the top of the

can. It is attached to the dip tube. It can work in two ways, one is when actuator is

pressed to open the valve and other is valve is pushed to the side in case of foam.

Components of Valve

Method of Filling Aerosol ContainerThis process involves four operations: - Product FillingRemoval of Air From Head SpaceBy evacuating air from head spacePurging (Addition of few drops of propellant)Sparging (Blowing of inert gas from product)

SwagingPropellant FillingLiquefied Gas PropellantPressure FillingUnder Cup Filling

Compressed Gas Propellant

Shake Well Before Use

Few aerosol products need to be shaken well before they can be use. This is to make sure that the product and propellant are well mixed. Many propellants aren’t miscible in product and makes two different layers of liquid. Without a good shake, there will be just a pool of propellant when the product runs out.

Advantages of Aerosol Containers Long shelf life of product Odour is preserved No contamination of product from bacteria or dust Contents do not evaporate Can dispense variety of products like gels,

powder, foams, gases, liquids etc. Cans are strong and safe Convenience to use Provides even coatings of paints Product can be sprayed at large distance

Disadvantages of Aerosol Containers

Use of CFCs Losses efficiency when compressed gas

propellant is used Complex design High manufacturing cost Highly flammable

Applications of Aerosol Cans Asthma inhalers Cleaning products Insect repellents Food products Deodorizers Disinfectants Paints Fire extinguishers Hair spray Shaving foam Room fresheners Rust lickers etc.

Latest Developments

In Relation to the New Formulation Incorporation of water to limit flammability of pack due to

butane propellant In India, pilot scale plants have been developed to

produce deodorized LPG

In Relation to the New Products Edible creams Antistatic sprays for cloths and carpets Fire extinguishers