The Direct Style of Printing on 100% Polyester by Varying the Print Fixation Methods
Rushikesh Digambar Patil
Department of Textiles (Textile Chemistry)
DKTE’S Textile & Engineering Institute, Ichalkaranji, India
Intern at Textile Learner
Email: rushikeshpatil23052002@gmail.com
Introduction: In the textile business, polyester fabrics play a significant role. The most suited dyes for printing on Polyester fiber materials are dispersed dyes, which produce prints with excellent overall fastness. Disperse dyes have a substantially higher washing fastness on polyester than acetate, triacetate, or nylon. They have a great dispersing capacity, making them easy to scatter in water. Various fixing procedures for dispersed dyes are listed below-
Atmospheric steaming
High temperature steaming
Pressure steaming
Thermofixation method
It’s crucial to choose the right dispersion dyes and thickeners. Dyes with low sublimation fastness can be utilized for air steaming and pressure steaming. Dyes with a medium to moderate sublimation fastness can be used for HT steaming, whereas dyes with a high sublimation fastness can be utilized for thermofixation.
Different Print Fixation Methods:
Atmospheric steaming
Pressure steaming
High temperature steaming
Thermofixation
Conditions-
1) Temperature = 102 to 105°C
2) Carrier is added
3) Time = 30 min
Conditions-
Temperature = 125 to 130°C
Pressure = 1 to 2 bar (25-30 psi)
Time = 30 min
Conditions-
1) Temperature =165 to 180°C
2) Time =5 to 20 min
Conditions-
1) Temperature =200 to 210°C
2) Time=120 to 130 seconds
Steam- Saturates Steam
Steam- Saturated Steam
Steam- Supersaturated
Steam- Supersaturated
a) Machine= Loop ager
b) Continuous process
a) Machine= Star ager
b) Continuous process
a) Machine= HT steamer
b) Batchwise process
a) Machine= Stenter
b) Continuous process
[Notes-
Saturated Steam: Once the water is heated to the boiling point, it is vaporized and turned into saturated steam It has moisture.
Supersaturated Steam: When saturated steam is heated above boiling point, dry steam is created and all traces of moisture are erased. This is called superheated steam. It doesn’t have moisture]
Mechanisms of Different Print Fixation Methods:
A. Atmospheric steaming: For 30 minutes, the fabric is held at 102-105°C for atmospheric steaming. We should include a carrier in the solution that causes the fiber to expand, allowing dyestuff molecules to easily permeate through it.
Because carrier dye can enter into the fine structure of polyester and push adjacent long-chain molecules apart, the molecular pattern loosens up, resulting in a lower (Tg) glass transition temperature of polyester. As a result, segmental vibration increases, allowing large dyestuff molecules to enter the polyester structure and disperse dye to become mechanically trapped.
B. Pressure steaming: The segmental vibrations increase and the glass transition temperature (Tg) decreases at such high temperatures and pressures. Long chains are pushed apart by this segmental vibration. Also, at such high pressures of 1 to 2 bar or 25 to 30 psi, dye penetration occurs under high temperature because the temperature drops after 30 minutes, and the dye particles become physically stuck inside the polyester framework.
C. High temperature steaming:
The temperature of the steam is excessively high, resulting in more and more segmental vibrations. As a result, the dye can permeate the fiber structure and is mechanically trapped after 20 minutes of supersaturation. Because steam is used, moisture is present; therefore, we add urea as a hygroscopic substance to enhance moisture.
D. Thermofixation:
Polyester melts at 230°C, hence its softening temperature is 200 to 210°C. At such high temperatures, such as 200 to 210°C, polyester becomes weakened around its melting point, and color particles diffuse inside polyester, attempting to become a part of polyester that cannot be separated.
The fabric is placed on the flat surface of the table, which is composed of soft material.
The screen is then placed on the cloth sample.
The printing paste is applied to the perforation on the screen.
With a smooth wooden strike, the paste is distributed over the screen with light pressure, allowing us to locate the printed cloth. So that the dye particles can pass through the perforation in the screen.
As a result, we have printed fabric.
Procedure: 1. Prepare the print paste as per the below recipe-
S/N
Parameters
Atmospheric steaming
Pressure steaming
High temperature steaming
Thermofixation
1
Temperature
102-105°C
125-130°C
165-180°C
200-210°C
2
Time
30 min
30 min
5-20 min
120-130 sec
3
Pressure
–
1-2 bar
–
–
Ingredients
Quantity
1
Disperse dye
3-5 gm
3-5 gm
3-5 gm
3-5 gm
2
Urea
—–
—-
2 gm
2 gm
3
Carrier
1 gm
—
—
—
4
Acid donar
1 gm
1 gm
1 gm
1 gm
5
Water
5-10 ml
5-10 ml
5-10 ml
5-10 ml
6
Sodium chlorate
1 gm
1 gm
1 gm
1 gm
7
Thickener
85-90 gm
85-90 gm
80-85 gm
80-85 gm
Total
100 gm
100 gm
100 gm
100 gm
The process sequence for different print fixation methods:
Atmospheric steaming
Pressure steaming
HT steaming
Thermofixation
Printing
↓
Drying
↓
Atmospheric steaming at 102-105°C for 30 min
↓
Wash
↓
Reduction cleaning at 60°C
↓
Wash
↓
Drying
Printing
↓
Drying
↓
Pressure steaming at 125-130°C & 1-2 bar pressure for 30 min
↓
Wash
↓
Reduction cleaning at 60°C
↓
Wash
↓
Drying
Printing
↓
Drying
↓
HT steaming at 165-180°C for 5-20 Mini
↓
Wash
↓
Reduction cleaning at 60°C
↓
Wash
↓
Drying
Printing
↓
Drying
↓
Thermofixation at 200-210°C for 120-130 sec
↓
Wash
↓
Reduction cleaning at 60°C
↓
Wash
↓
Drying
2. Print the given polyester fabric sample with the above recipe
3. Dry the sample at 80°C
4. Carry out fixation by following methods:
Atmospheric steaming: at 102 to 105°C for 30 minutes
Pressure steaming: at 125 to 130°C for 30 minutes at 25 psi in a pressure steamer.
High Temperature steaming: at 180 0C for 7-8 minutes in a superheated steamer.
Thermo fixation- at 200-210°C for 30-60 seconds on stenter.
5. Rinse the fabric samples with warm water after fixation and perform a reduction clearing procedure at 60°C for 20 minutes using 2 GPL NaOH and 2 GPL Hydros.
6. Wash the sample with hot, cold, and dry water after this treatment.
Advantages & disadvantages of the process:
Atmospheric steaming
Pressure steaming
HT steaming
Thermofixation
Advantages-
1. Disperse dye with low sublimation fastness can be used
2. This process has a High production rate
3. It is a continuous process
4. Bright prints with full-color yield can be
Advantages-
1. Disperse dye with low sublimation fastness can be used
2. No carrier we used
3. Bright prints with full-color yield can be
Advantages-
1. This process has a High production rate
2. It is a continuous process
3. Bright prints with full-color yield can be achieved
4. No Carrier is used
Advantages-
1. This process has a High production rate
2. It is a continuous process
3. No carrier is used
Disadvantage-
1. Carrier is required
2. Time consuming process
Disadvantage-
Lowest production rate
Required special machine
Disadvantage-
1. Low sublimation fastness Disperse dye can’t be used
2. Require special machine for high temperature
Disadvantage-
1. Low sublimation fastness Disperse dye can’t be used
2. Prints are not bright
3. 10-15% color yield is lost due to high temperature
Resultant samples fixation methods are:
Conclusion:
Above all these print fixation methods, the pressure steaming method gives the brightest prints. Every method has its advantages as well as disadvantage so, as per requirement we can produce prints with different methods.
Founder & Editor of Textile Learner. He is a Textile Consultant, Blogger & Entrepreneur. Mr. Kiron is working as a textile consultant in several local and international companies. He is also a contributor of Wikipedia.
