LYCRA,SPANDEX AND OTHER ELASTANE DYEING WITH DIFFERENT COLOR COMBINATIONS AND DYES AND ITS PROCESS STUDY ACCORDING TO TEMPERATURE AND PRESSURE SUITABILITY ACCORDANCE TO DYEING PARAMETERS

1. Presentations
@IIT-D
BY
VIVEK YADAV
9457631264

2. A Presentation On
Dyeing Of Elastane
Submitted By
Vivek Yadav
Submitted To
Dr. B.S. Butola

3. Brief History
 Spandex derived from the term expands
 Spandex is preferred name in North
America , elsewhere it is referred as
elastane
 Development started during World War II.
 F. Bayer, earned a German patent for his
synthesis in 1952.
 Du Pont as brand name Lycra started full
scale manufacture in 1962.

4. Basics about Elastane Fibre
It is a synthetic polymer made up of a long-chain polyglycol combined with a
short di-isocyanate, and contains at least 85% polyurethane.
Two Segments (long, amorphous segments and short, rigid segments).

5. Basic Properties overview
• Physical Properties of Spandex
Fiber:
• Cross section- non-circular cross-
sectional shapes.
• Density: 1.15 to 1.32 g/cc,
• Moisture regain 0.8 - 1.2%
• Tg -20°C
• Breaking tenacity: 0.6-0.9
grams/denier.
• Elongation- 300%-400%
• Luster: dull luster.

6. Pretreatment; Bleaching ?
• Can be bleach by hydrogen peroxide in a best way .
• Not hypochlorite bleaching because they degrade polyurethane.
• Cellulose/polyurethane fibre blend can be bleached using hydrogen peroxide where
as synthetic/PU fibre blend needs no bleaching agent. where the fabric is treated only
with soda ash and other auxiliaries.
Why not Hypochlorite bleaching
It may cause yellowish color

7. Free radical degradation of Elastane due to NaOCl bleaching
Reference-Chlorine Degradation of Polyether-Based Polyurethane
SANDEEP KHATUA, YOU-LO HSIEH
Fiber and Polymer Science, University of California at Davis, Davis, California 95616

8. PU dyeing ?
Dyeing difficult ?
• Complicated distribution of soft &
hard segment.
• Lack of dye reacting sites
That’s why elastane has been divided
in two groups
• Simple elastane( trapping in hard segment
of the polymer chain ,needs after treatments)
• Dye-able elastane- Development of
dyeing sites
( U.S. patent number US 7,838,617 B2 )

9. Dye able Elastane
The Poly-Urethane-urea is prepared using a combination of 4,4'-MDI (4,4'-Methylene-
diphenyl di-isocyanate) and 2,4-MDI, and an amount of chain extenders and chain
terminators.
Chain terminators-Include secondary amines, for example diethylamine (DEA)
Result- Resulting polymer chain having NH- group which will behave like wool , nylon and silk (
dyeing sites) and can be dyed with the help of acid , reactive , metal complex dyes.
Fabrics made up of dyeable elastane will cause better over all fastness
Reference-DYEABLE SPANDEX, United States Patent, Patent No.: US 7,838,617 B2, Date of Patent: *Nov. 23, 2010

10. Dyeing Of Polyurethanes
• Mostly it is only 2-5% of the total fabric.
• Due to high cost of dye-able Elastane they go to obscure it with different fabric structure, high shade
dyeing dominant fibre ( polyamide , cotton , PET etc)
Dyes may use -Acid Dyes , 1-2metal Complex , Chrome Dyes ,Desperse Dyes ,
( heavy shade needs after treatment with tannic acid to improve the fastness properties.)
Dyeing Recipe
Acetic acid – for pH balance in acidic range
Dye- Pre- Metalized Acid Dyes
Temperature - ~90 °C
Holding time – depends on shade and dye affinity
0
50
100
0 50 100 150
Temp.
90° C
Time ( minutes)
2°C/minute
60°C

11. Blend dyeing ; Elastane with cellulosic Material
What if cellulose is dominant ?
Process ?
Dyed with separate dyes , acid and reactive
Polyurethane is first dyed with disperse/acid/metal complex dyes followed by
reactive dyeing.
Medium and heavy shades- Acid or Metal complex dyes
Needs after treatment with tannic acid to improve light fastness property of
dyed material.
Recipe for dyeing –
As usual dyeing recipe for separate acid and reactive dyes , but low pH
reactive dyes requires

12. Dyeing of elastane/ polyamide blends
PROBLEM ?
As the dyes used to be hydrophobic in nature , favors polyamides and rush towards it
quickly. Causing unleveled dyeing
SOLUTION?
We use anionic retarders which competes with dyes for dye sites on the fibres cause level
dyeing on both the fibres
ANIONIC RETARDERS?
Sulphonic acids, such as naphthalene sulphonic acid . It consist about 2%.
For combined dyeing of elastane and polyamide blends , following is the recipe
Dye- Metal complex dyes,
Acetic acid- as pH maintainer
Anionic retarders- Sulphonic Based Organic
Compounds.
REFERENCE- U.S PATENT NO. 3653798 0
50
100
0 50 100 150
Temp.
Time (minutes)
Anionic retarder at 70°C
Dyeing ~ 95°C

13. Dyeing of polyester elastane blends
• Both the polyester and the spandex are
hydrophobic fibers and both can take dispersing
dyes,
• What at low temperature?
• PU take up high disperse dyes ( below 100°C)
• What at high temperature?
• From 100°C, dye began to rush towards PET ,
by holding it to 130°C , we get even dyeing
• Problems ?
• Elastane is not suitable for high temperature
dyeing as PET requires high temperature
dyeing.
• Solution ?
• Carrier ?
• It will lower down the Tg of PET, creates
possibilities to dye around 98°C .
• It will followed by a reduction clearance
process to achieve better washing fastness of
the blends, specially from elastane.

14. Dyeing recipe
Disperse dye- as required
pH regulator (ammonium acetate) - .1-2 gpl
Carrier - .1-1 g.p.l. ( Organic compounds having phenols)
MLR ration 1-5 and up to 1-50
pH = ~ 4 to 6
Temperature ~ 100 °C
Reduction clearance
sodium dithionite – 0.1 to 4 gpl
sodium hydroxide- .1 to 3 gpl
Soaping agent - .2 to 3gpl
Temperature- 70°C
Note
The dispersing dye is related to a low temperature or moderate temperature dispersing dye.
Resultant dyed fabric will provide following fastness value-
Grade 4~5 of changed color in soaping;
Grade 4~5 color fastness to sunlight;
Reference-Polyester -spandex elastic fabric dyeing method Europian patent-EP 2 067 892 A1
dated-10.06.2009

15. References
• Textile Science: An Explanation of Fibre Properties by E.P.G. Gohl & L.D. Vilensky, 2nd
edition , page no. 98-105
• DYEABLE SPANDEX, United States Patent, Patent No.: US 7,838,617 B2, Date of Patent:
*Nov. 23, 2010
• METHOD FOR DYEING FABRIC COMPRISING ELASTOMERIC FIBER, United
States Patent, Patent No.: US 6,613,103 B2, Date of Patent: Sep. 2, 2003.
• STUDY OF PROCESSES OF DYEING POLYURETHANE FIBRES BY VARIOUS
CLASSES OF DYES, by A. E. Tret’yakova, V. V. Safonov, and A. Yu. Yusina, Fibre
Chemistry, Vol. 44, No. 5, January, 2013 (Russian Original No. 5, September-October, 2012)
• Processing of polyurethane fibre and its blends, Article in Man-Made Textiles in India ·
July 2003, byBharat H Patel.
• PROCESS FOR THE DYENGS OF BLENDS OF SPANDEX FBERS ANDPOLYAMDE
FIBERS, United States Patent, George Leslie Boardman, patent no. 3,653,798, Date-Apr. 4,
1972
• PROCESS FOR DYEING SPANDEX FIBERS, Inventor: Jai P. Sharma, Hickory, N.C.,
United States Patent, Patent Number: 5,382.264, date-Jan. 17, 1995
• METHOD FOR DYEING FABRIC COMPRISING ELASTOMERC FIBER, Inventors:
Robert FImmediato, Patent No.: US 6,613,103 B2, Date of Patent: Sep. 2, 2003
• Chlorine Degradation of Polyether-Based Polyurethane SANDEEP KHATUA, YOU-LO
HSIEH Fiber and Polymer Science, University of California at Davis, Davis, California 95616