Presentation on Foam Dyeing
• Presented by:-
– Ananna Rahman(18/13)
– Naimul Hasan Shuvo(04/13)
– Abdullah Al Bitar(09/13)
– Md. Anisur Rahman(05/13)
– Md. Shariful Huda(35/13)
– Sk. Asgar Hossain(08/13)
– B.M. Tanimul Islam(06/13)
– Md Naim Hasan
• Presented to:-
- Maitry Bhattacharjee
- Shayamoli Textile
What is foam?
Foam is a dispersion of a gas in a liquid.
Here the liquid is generally water and the
Gas is generally air but it may
also be an inert gas. It’s a colloid
Example of foam:
Structure of foam
A dispersion is a system in which particles are dispersed in a continuous
phase of a different composition or state.
An emulsion is the mixture of two or more immiscible liquids which are
mixed with the help of an emulsifier.
An emulsifier is a compound or substance that acts as a stabilizer for
emulsion preventing the liquids from separating. Also known as emulsifying
A solution is a homogeneous mixture, composed of two or more solutes
dissolved in a solvent.
Difference between Foam and
It’s a dispersion of gas in a liquid. It’s a mixture at two immiscible
Foam is unstable. Comparatively more stable than
Foaming agent is used Emulsifier is used.
Comparatively complex in formation. Formation is easier.
It contains 2 phases. It contains only 1 phase.
Difference between Normal foam and
Stability Less stable More stable
4-6 minutes Much longer
Viscosity Less More
Example Foam produced using soap or
detergent with water
Foam used in modern textile
Topic Normal Foam Dyeing Foam
Bubble size Greater Smaller
The process of dyeing where the main dyeing medium is foam, is called
– In foam dyeing a fabric is padded with foam.
– Foam is formed from a aqueous solution of a dye stuff, a foaming agent & a
the dye stuff.
– The padded fabric is maintained at
elevated temperature to fix the dye.
Reasons for using foam dyeing:
• To eliminate drying step.
• Saving energy.
• Reducing environment pollution.
• To reduce wet pick up.
• To improve product quality.
• To reduce investment cost.
• To reduce the material : liquor ratio.
A foaming agent is a material that facilitates formation of foam such as a
surfactant or blowing agent that helps to maintain it’s integrity by
strengthening individual foam bubbles.
Example:- Linear alkaline derivatives such as sodium lauryl sulphate
The foaming agents can be anionic, cationic, non-ionic or amphoteric.
Requirements of foaming agents:
1. Generate foam readily.
2. Offering a good wetting capacity.
3. Should perform fast and uniform wetting action.
4. Foam generation capacity according to required size & stability.
5. It should show little or no effect on color fastness.
6. It should not cause yellowing of white materials.
7. It should be capable of producing various bubble sizes to meet specific
Materials used for Foam Dyeing
• White fabric – Cotton, rayon, silk or other natural fiber to dye on.
• Soda ash fixer.
• Squeeze bottles to hold the dyes.
• Foam shaving cream, preferably containing aloe.
• Flat, shallow, plastic or metal pan.
• Wire whisk.
Types of Foam
Depending on the concentration of foaming agent used & method of
foaming properties there are 2 types of foam:-
Density 0.2 gm/l
Contain less liquid in bubble.
Metastable & more stable.
Polyhedral structure which may vary in size.
Density is least 0.35 gm/l
Spherical bubble size.
Not suitable for textile use.
Broadly there are 2 types of foam:-
Dispersion foam: It is produced by the introduction & mixing of gas from
an external source into a liquid phase. In textile field dispersion foam is
Condensation foam: It results from the generation of a gas within the
liquid either by chemical or by a physical change. This type pf foam is not
used in textile field.
Foam stabilizer slows down the drainage of liquids from the bubbles &
impart workable flow properties.
The basic role of a stabilizer in foam is to reinforce the bubble cell wall to a
controllable level or stabilize foam from decay.
– Hydroxy-ethyl cellulose (HEC)
– Methyl cellulose
– Ammonium stearate.
Function and Requirements
• Slow down drainage.
• Reinforce bubble cell-wall.
• Controls life time of foam.
Requirements of stabilizer:-
- Easy solubility.
- Compatible with a foam finishing system.
- Effective at low concentration.
- It should be easily soluble.
- It should be least affected by fabric handle.
- Resistance of bacterial attack.
Factors considered for foam dyeing
• Dilution factor:- Related to fabric cover factor. If cover factor is higher
(dense or coarse fabric in general) lamella size should be higher. i.e. –
large cover factor, more dilution. Less cover factor, less dilution.
• Foam stability:- If bubble size is higher foam will be less stable.
• Foam decay half-life:- time required to drain out half of the foam.
• Foam decay:- Self drainage of a foamed liquid.
• Foam density:- The foam must have uniform density.
𝛿 = volume of solution consumed / volume of foam.
• Blow ratio:- It expresses the volumetric ratio of liquid to foam. It’s a
measure of dilution of foam.
Blow ratio =
Factors considered for foam dyeing
• Drop escape time:- The time taken to drain out the first drop of liquid
from the foam is called drop escape time. The drop escape time normally
ranges from 45s-90s.
• Viscosity:- If blow ratio increases, viscosity of foam decreases. If
viscosity increases foam stability decreases.
• Homogeneity:- For uniform application homogeneous bubbles of
smaller size are essential. They should be made of constant size as nearly
• Bubble size:- The size of the bubbles and it’s rate of changes determines
foam penetration into the textiles. Foam of smaller bubble size is
generally more stable than that of larger one.
Methods of Foam Dyeing
There are 6 methods currently available for foam dyeing. They are:-
1. Foam application on a horizontal padding mangle.
2. Foam application with a coating blade.
3. Foam application by pressure nozzle.
4. Foam application with a rotary printing screen and slit doctor.
5. Two sided foam application with transfer rollers and dosage shoots.
6. Foam application by indirect doctor blade dosage foam collapse by
vacuum cylinder suction.
Foam application on a horizontal
• Contains 2 horizontal padding bowls side by side.
• The foam is applied to the both side of fabric at the nip of the bowl.
• Suitable for woven fabric.
Foam application with a coating blade
• Uniform and consistent foam is generated and afix amount of foam is
deposited on the fabric.
• The rate of dosing is controlled by setting of blade.
• The foam is deposited by laying it on the fabric.
• The fabric then goes through the nip of two rollers to completely
collapse the foam.
• A double coating knife coater is useful in this method.
Foam application by pressure nozzle
• Specified amount of active chemical is delivered to a mixing head and
then to a fabric.
• The foam is applied to a pressurized zone .
• The pressure is slightly above the atmospheric pressure.
• The pick up of foam system depends on whether light or dense foam is
• The foam is driven upwards through the slot nozzle.
• The foam causes rapid collapse as soon as it touches the fabric.
Foam application with a rotary
printing screen and slit doctor
• Brand name: RSF FOAM APPLICATION
• Foam is pressed through the triangular screen by a specially designed slit
• For both side application a dual application is available.
Two sided foam application with
transfer rollers and dosage shoots
• Foam shoots by inclined plates situated at the base.
• Foam is trapped between the fabric and roller.
• As fabric is pressing against the roller and passing, the foam collapse.
• The uniformity of foam application depends on fabrics moisture content,
roller pressure etc.
Foam application by indirect doctor blade dosage
foam collapse by vacuum cylinder suction.
• Doctor blade doses the foam onto and endless rubber belt which come
in contact with the fabric.
• The rubber belt seals the vacuum cylinder creating high vacuum which
draws the foam forcibly into the fabric.
• There the bubble expand and break and the foam collapse. The dosage
rate is controlled by the slit setting of doctor blade.
Advantages of Foam Dyeing
Save chemicals(0-20% minimum)
Reduce water pollution.
Faster production .
Less heat generation., Save energy.
Reduction of shrinkage in width because of low liquor application
Printing do not need thickener.
Greater productivity which is around 25-50% more than conventional
Low liquor ratio .
Lower dyes migration.
Scope for the development of novel fabrics.
Disadvantages of Foam Dyeing
Limited application, only for cotton and polyester products. i.e. carpets ,
carpet backing coating etc are popular.
Investment cost is more ( for equipment )
Skilled man power is required.
In some cases problem arises in penetration of levelness.
More attention required.
New machine required.