1.
Mass Colouration and Dope Dyeing

2.
Mass Colouration:
Mass Colouration is a technique of colouration of synthetic fibre during fibre
spinning. Pigments or insoluble dyes are added in the molten polymer or
spinning solution.
According to the process colourants are incorporated into polymer mass
during polymerization or fibre spinning.
 All natural fibre are dyed by solution dyeing technique
 Synthetic and regenerated fibre can be coloured by mass colouration
technique
Viscose is the first fibre manufactured by this tecnique.
Advantages:
This mass colouration is a water free dyeing.
It does not require any auxiliaries or dye bath assistant during colouration
No waste of colouring materials
Affinity of colour material towards fibre is not any issue for this type of
colouration of textile fibre.
 It a single stage colouration process

3.
Disadvantages of Mass Colouration:
Limited numbers of shades are available
Colour brightness is an issue
Small lot size is not possible
Frequent change of shade is not possible
Down time for cleaning of the system is very high

4.
Dope Dyeing:
This a dyeing technique of regenerated fibre during fibre spinning. In this
method insoluble dyes or pigments are added in the spinning solution during
fibre extrusion through spinnerets.
This type of colouration gives excellent colour fastness to the fibre.
This is an ideal process of colouration which replace the dyeing process in
manufacturing process.
Production capacity increases
Reduces time of production
Reduces process cost
Reduces process stage

5.
Different Mass Colouration Techniques
Addition of colourant during polymerization
Chips dyeing
Chips coating
Master batch addition during fibre spinning
Injecting colour material into extruder during
fibre spinning
Melt in melt metering system

6.
1. Addition of Colorants during polymerization:-
• Carbon black (1.5-2.5%) is mainly used for the production of
black colored polyester.
• Some heat stable colorants which need no dispersing and
grinding are available namely sandoz, ciba, ICI.
• Nylon has a powerful reducing action on colorants and very few
colorants are stable under high temperatures of the molten
polymers.
2. Chips Coating :-
In chips coating colorants in one form or another are applied to
the surfaces of the chips uniformly without the necessity for
special mixing procedures.
• Generally acid dyes are used for nylon chips. The chips are
thoroughly dried and melt spun to get the coloured polyester
and nylon filaments.

7.
3. Chip Dyeing:-
The idea of chip dyeing seems to have originated polymer chips.
 This method is not used commercially for polyester chips, but it is
frequently used for nylon 6 and to a less extent for nylon 6,6. Nylon 6
production requires aqueous monomer extraction and it is convenient
to combine dying of the chips with acid and metal-complex azo dyes
during monomer extraction and the subsequent drying operation.
4. Master batch addition :-
In this system colored polyster or nylon chips containg 10-15% of
disperse and acid dyes are first produce using a polymer such as
polyethylene or nylon6.
 Coloured chips are commercially availiable .
 The coloured chips are then blended with white chips in desired
proportion and then spun to get coloured fibres.
 Master batch system is used for nylon polyester and polypropylene
by a variety of mixing techniques.

8.
5. Injecting color in to the polymer chips in to the extruder:-
 Polymer soluble dyestuff powder is directly added to the
polyester or nylon chips stream just before spinning extruder.
6. Melt in melt metering system:-
 Polymer soluble colourants and white polyester or nylon are
melted in a separate melter.
 The colourant stream is then mixed with polymer stream
coming out of the polycondensation.
 This method is cheaper than the other methods.

9.
Methods:- Mass Colouration Method are two types
 Continuous Method
 Discontinuous Method
 Continuous Method:-
During the continuous process (for large tonnages) the molten
polymer enters directly into the Pumps and the spinneret after
polycondensation in the continuous reactors.
 Discontinuous Method:-
In the discontinuous process the polymer leaves the poly-
condensation reactor is cooled and transformed into Chips.
These granules are stored in dried condition and furnished on
demand to the melters.
This procedure is more easily adaptabted to small quantities.

10.
The polyamide material coloured by this method contains
the dye in a very fine dispersion and may therefore be spun
satisfactorily into very fine textile filaments and threads.
At a liquor ratio of from about 1:1 to 4:1 polyamide
granules (chips) are coloured up to exhaustion of the dye
liquor at the boiling temperature. To accelerate absorption
and to increase the degree of absorption it is advantageous
to carry out dyeing in a weakly acid medium.
The amount of dye may be varied within wide limits; it
depends on the depth of colour desired.
Mass colouration of polyamide fibre

11.
 Recycled polyethylene terephthalate nanofibers were
fabricated through electro-spinning technique.
 Prior to that, r-PET bottles were cut into small pieces
(approximately 1 × 1 cm2 ) followed by dissolution in
TFA/Chloroform with ratio 1:3 for making different
polymer compositions,
 The dye 2% (0.006 g) was added in each polymer
composition for observing the effect of dye on each
polymer composition
 Furthermore, the dye 0.5%, 1%, 2%, 3%, and 5% on
weight of polymer composition 15% was added to observe
the effect of dye concentration on polymer composition.
 The solution was further stirred for 15 min to achieve
proper dye dispersion
Mass colouration of Polyethylene Terephthalate(PET)

12.
• Nylon has a powerful reducing action on colourants and very few
colourants are stable under high temperatures of the molten polymers.
• Nylon can be dyed in various process of mass colouration-
 Addition of colorants during polymerization
 Chip dyeing- Chip dyeing process is frequently used for nylon 6 and to
a less extent for nylon 6,6. Nylon 6 production requires aqueous
monomer extraction and it is convenient to combine dying of the chips
with acid and metal-complex azo dyes during monomer extraction and
the subsequent drying operation.
 Master batch addition-In this system coloured nylon chips containing
10-15% of disperse and acid dyes are first produce using a polymer such
as nylon 6.
 Melt in melt metering system – Here nylon are melted in a separate
melter. The colourants stream is then mixed with polymer stream
coming out of the polycondensation. This method is cheaper than other
methods.
Mass colouration of nylon

13.
• Polypropelene fibre are mainly coloured by mass coloration.
• The pigments suitable for spin colouration are commercially available
in form of pigment dispersed in carrier, in the form of powder or
granules and known as “pigment preparation” or “master batch”.
• The pigment content of master batch is generally 20-40% in case of
organic pigment and about 50% in inorganic pigment.
• The pigment stability deciding factors for spin colouration are; heat
stability, dispersibility, fastness properties especially light fastness and
solubility in polymer melts
Mass colouration of polypropylene

14.
Colourants for Polypropelene fibre