Table of Contents
Wrinkle Resistant Finish .......................................................................................................................... 3
Mechanism of wrinkle formation ........................................................................................................... 3
Steps involved in resin finishing .............................................................................................................. 5
1. Impregnation of fabric in pre-condensate solution .................................................................... 5
2. Curing of impregnate materials .................................................................................................. 5
3. Washing and soaping .................................................................................................................. 5
4. Softening and drying ................................................................................................................... 5
Urea-formaldehyde precondensate ....................................................................................................... 6
Typical recipes for finishing with urea-formaldehyde precondensates ................................................. 7
Dimethylol ethylene urea (DMEU) .......................................................................................................... 7
Typical recipes for finishing with DMEU ............................................................................................. 8
Use of DMeDHEU .................................................................................................................................... 9
Typical recipes for finishing with DMDHEU ...................................................................................... 10
Effects of wrinkle-resistant finish through resins ................................................................................. 10
Samples of fabrics before and after application of finishing process ................................................... 11
Recovery angle of different types of fabrics before and after finish .................................................... 12
Tensile strength for different types of fabrics before and after finish (warp way) .............................. 12
Tensile strength for different types of fabrics before and after finish (weft way) ............................... 13
Stiffness of different types of fabrics before and after finish (warp way) ............................................ 13
Stiffness of different types of fabrics before and after finish (weft way)............................................. 14
Key observations : ................................................................................................................................. 14
References ............................................................................................................................................ 16
Wrinkle Resistant Finish
Durability, ability to withstand rough laundering treatment under alkaline condition, good
perspiration absorption characteristics, comfort wear and ability to take up a wide range of dyestuffs
make cotton ideal for apparel purpose. However, proneness to creasing under slight crushing and
retention of the creases for a long time give cotton garments a poor rating during actual wear.
The ability of a fabric to resist the formation of crease or wrinkle when lightly squeezed is termed
the crease resistance of the fabric and associate with fabric stiffness. A crisp fabric that does not
bend easily resists the formation of creases and may be termed crease resistant. The ability of the
fabric to recover to a definite degree is called crease recovery of the fabric. Since this deals with
internal linking of the fibre molecules, it can be modified by chemicals which will penetrate the fibre.
Mechanism of wrinkle formation
In the cellulosic fibre substance, cellulose macromolecules form crystalline and amorphous regions
depending on weather they are bound by side-ways links like hydrogen bonds between the hydroxy
groups of adjacent macromolecules or not.
Fig: i Role of hydrogen bonds in forming crystalline region
The hyrodxy group of the amorphous region are far apart and since hydrogen bonds operate at short
distances, these hydroxyl groups remain unbound. When a cotton cloth are folded and pressed,
some of the hydrogen bonds at the boundary of the crystalline and amorphous regions break
(hydrogen bonding forces are fairly week); simultaneously free hydrogen bond in amorphous region
approach other free hydroxy groups and when they are sufficiently close to each other they get
bound. These newly formed hydrogens bonds bind the molecules and prevent unfolding, i.e. the
crease becomes more or less permanent. However, when it is unfolded and ironed with a hot iron
newly formed hydrogen bond breaks and the cloth reaches its earlier state and crease vanishes.
Thus the creasing behaviour of cotton fabric may be directly linked to the ability of the free hyroxy
groups in the amorphous region to get bound to each other. This suggests that if one wants to make
cotton crease resistance, the hydrogen bond forming capacity of the hydroxyl groups should be
either masked or totally removed.
Another method of minimising the problem of creasing involves the reaction of the hydroxyl groups
of adjacent cellulose macromolecules with certain chemicals, thereby cross-linking the molecules.
Formaldehyde may be used for the purpose.
Fig: ii Formation of methylene crosslink during the reaction of formaldehyde with cellulose
Two objectives are achieved by this crosslinking. Firstly, the hydrogen bond forming capacity of the
cellulose hydroxy groups involved in cross-linking is removed. Secondly, the introduction of cross-
links imparts dimensional stability to the fibre material and makes it more resistant to wrinkle
formation.
Steps involved in resin finishing
Normally cross-linking agents applied by Pad - Dry - Cure method.
The application of Urea Formaldehyde resin consists of the following steps:
1. Impregnation of fabric in pre-condensate solution
Before impregnation, the materials should be scoured and bleached for better penetration
of liquor. Dyed and printed fabrics can be taken directly.
The concentration solution of resin precondensate is diluted depending on the type of fabric
and to this; acid catalyst and other additives such as softeners PE emulsion are added.
Ammonium Salts such as Diammonium Phosphate (DAP), Diammonium Dihydrogen
Phosphate (DADHP), NH₄Cl₂, (NH₄)₂SO₄, MgCl₂.6H₂O, Zn (NO₃)₂.6H₂O are used as acid
catalyst with exact amount. The fabric is padded by using either two or three bowl padding
mangle with an expression of about 80% at RT. After padding, the material is dried in stenter
with minimum tension at 70° - 80°C.
Higher temperature of drying leads to migration of finishes causing to loss of tensile strength
and abrasion resistance of fabric.
2. Curing of impregnate materials
After drying, the material is cured at 120° - 150°C for 2 - 5 mins. In a high temperature
Stenter machine.
Cross linking and polymerisation take place during curing process.
3. Washing and soaping
After curing the material should be washed in open width or rope form in a dilute solution of
soap and soda ash.
The purpose of this washing is to neutralise the residual acidity and also to remove any
combined reagent which causes undesirable effect.
The fabric may be washed with 1 - 2 gpl of anionic wetting agent (TRO) and 2 - 4 gpl of soda
ash at 50° - 60°C for 10 mins.
4. Softening and drying
After washing, the material is rinsed in water containing softening agent.
Then finally it is stentered in ordinary stenter to dry and to get even width of fabric.
Urea-formaldehyde precondensate
The reaction between urea and formaldehyde in neutral or alkaline medium result primarily in the
production of monomethylol urea or dimethylol urea (DHU).
These methylol compounds are very reactive and their isolation in their pure state is difficult. During
drying of such compounds further reaction take place with the elimination of water.
Fig: iii Chemical structure of MMU & DMU
Fig: iv Crosslinking of cellulose macromolecules by DMU
Typical recipes for finishing with urea-formaldehyde precondensates
Compound Pad liquor composition for
Cotton Viscose rayon Polyester/viscose
UF Precondensate 100-150 g/l 100-200 g/l 80-120 g/l
Cationic softener 8-10 g/l 8-10 g/l ---
Diammonium phosphate 5-6 g/l 5-10 g/l ---
Magnesium chloride
hexahydrate
--- --- 5-7 g/l
Polyethylene emulsion --- --- 15-20 g/l
Wetting agent (Anionic) 5 g/l 5 g/l --
Curing
Temperature 140-150°C 140-150°C 140°C
Time 4-5 min. 4-5 min. 3-4 min.
Fig: v Formation of U-F resin
Dimethylol ethylene urea (DMEU)
There are certain disadvantages associated with cross-linking and resin deposition in cellulosic
materials to impart crease resistance to them. For example, excessive cross-links confer
embrittlement (called crosslink embrittlement) on the treated materials; as results the tear strength
of the materials deteriorates. Further, the abrasion resistance of the fabrics is also decreased due to
resin deposition. The hand of the fabric attains a certain degree of harshness and stiffness. Thirdly,
the -NH- groups of the crosslink are susceptible to hypochlorite solutions. When the resin treated
fabrics are with sodium hypochlorite solutions during the laundering, the chlorine from the bleach
liquor is retained by the crosslink at the -NH- group (which becomes -NCl) which then becomes
sensitive and the crosslink is broken, thereby losing a part of the crease resistance. This defect is
called the chlorine retention of the resin. This is also associated with the yellowing tendency of the
resin-treated fabrics.
Fig: vi Dimethylol ethylene urea
In order to overcome these defects (especially the chlorine retention) cyclic ureas are used (instead
of urea) where the hydrogen of the -NH- groups is replaced.
Typical recipes for finishing with DMEU
Compound Pad liquor composition
Cotton suiting Viscose rayon Polyester/cotton Polyester/viscose
DMEU (as
marketed)
80-100 g/l 150-200 g/l 50 g/l 100 g/l
Polyethylene
emulsion (as
marketed)
20 g/l 15-20 g/l 3-5 g/l 5-7.5 g/l
MgCl₂ 6H₂O 8-10 g/l -- -- --
Glacial acetic acid -- 1.5-2 g/l 1 g/l 1 g/l
Zn(NO₃)₂ 6H₂O -- 12-16 g/l 3-4 g/l 5-6 g/l
Use of DMeDHEU
DMeDHEU is applied by pad-dry-cure technique using various catalysts such as zinc nitrate
hexahydrate in the presence of Acetic acid. Curing may be carried out at 160˚ C for 3
minutes.
Cotton fabrics treated with DMeDHEU are superior to DMEU treated or DMDHEU treated
fabrics in resistance to chlorine damage and resistance to finish removal by acid. However
DMEU treated fabrics have high crease recovery angles. DMDHEU treated fabrics exhibit
high crease recovery angles, but the fabrics show a tendency of yellowing on curing and are
highly susceptible to chlorine damage.
Fig: vii Dimethyl dihydroxy ethylene urea
Typical recipes for finishing with DMDHEU
Compound Pad liquor composition
Fine cotton(g/l) Coarse
cotton(g/l)
Polyester/cellulose
suiting(g/l)
Durable
Press(g/l)
Effects of wrinkle-resistant finish through resins
Advantages of finished textiles over unfinished textiles especially after washing :
Improved dimensional stability and shape retention
Less tendency to creasing
Easier to iron
Softer and smoother
Better appearance and higher durability
Less variation in shade
Improved wet fastness of dyeing and prints
Less tendency to pilling, especially of fibre blends
Greater wash resistance of mechanically produced lustre
Reduced swelling of cellulosic fibres – without this finish, cellulosic fibres take up
more than 10% of their weight in water
Samples of fabrics before and after application of finishing process
Recovery angle of different types of fabrics before and after finish
Particulars Warp way angle (degree) Weft way angle (degree)
Before finish After finish Before finish After finish
1.100% cotton
woven fabric
76 142 80 125
2.99% cotton
and 1%
spandex
blended fabric
64 126 100 130
3. 98% cotton
and 2%
spandex
blended fabric
124 154 58 84
4. 65% cotton
and 35%
spandex
blended fabric
98 92 107 116
Tensile strength for different types of fabrics before and after finish
(warp way)
Particulars Tensile strength(Pound)
Before finish After finish
1.100% cotton woven fabric 142 71
2.99% cotton and 1%
spandex blended fabric
99 64
3. 98% cotton and 2%
spandex blended fabric
130 79
4. 65% cotton and 35%
spandex blended fabric
45 40
Tensile strength for different types of fabrics before and after finish
(weft way)
Particulars Tensile strength(Pound)
Before finish After finish
1.100% cotton woven fabric 170 119
2.99% cotton and 1%
spandex blended fabric
166 130
3. 98% cotton and 2%
spandex blended fabric
212 111
4. 65% cotton and 35%
spandex blended fabric
171 165
Stiffness of different types of fabrics before and after finish (warp
way)
Particulars Front left Front right Back left Back right
Before
finish
After
finish
Before
finish
After
finish
Before
finish
After
finish
Before
finish
After
finish
1.100%
cotton
woven
fabric
2.2 2.3 2.1 2.2 2.0 2.1 2.2 2.0
2.99%
cotton
and 1%
spandex
blended
fabric
2.25 2.4 2.2 2.5 2.4 2.45 2.5 2.6
3. 98%
cotton
and 2%
spandex
blended
fabric
3.0 3.6 2.6 2.8 2.6 3.9 3.0 3.6
4. 65%
cotton
and 35%
spandex
blended
fabric
3.6 4.1 3.7 3.8 3.3 4.0 3.2 4.1
Stiffness of different types of fabrics before and after finish (weft way)
Particulars Front left Front right Back left Back right
Before
finish
After
finish
Before
finish
After
finish
Before
finish
After
finish
Before
finish
After
finish
1.100%
cotton
woven
fabric
2.5 2.6 2.6 2.7 2.5 2.8 2.5 2.6
2.99%
cotton
and 1%
spandex
blended
fabric
2.2 2.4 2.2 2.3 2.0 2.2 2.0 2.3
3. 98%
cotton
and 2%
spandex
blended
fabric
2.6 2.9 2.45 2.6 2.2 2.5 2.3 2.5
4. 65%
cotton
and 35%
spandex
blended
fabric
2.7 3.0 2.5 3.0 2.7 3.1 3.1 3.0
Key observations :
Tensile strength of the fabric is reduced both in the warp and weft directions. It is
found that the decrease in tensile strength of finish fabric as compared to unfinished
fabric is 64% in warp direction and 43% in weft direction. It is observed that as the
curing temperature increases at constant dwell time, there is observed strength loss
in both fabric warp and weft. Higher the temperature, greater is strength loss. The
increase in concentration of resin with respect to catalyst, there is increase in loss of
tensile strength in fabric.
On comparing wrinkle recovery of fabrics, it is observed that the treated fabrics
show 42% increase in wrinkle-recovery angle in warp direction and 32% increase in
weft direction over untreated fabrics.
Significant improvement of wrinkle recovery is observed both in the warp and weft
directions.
Tensile strength and tear strength loss percentage observed with twill fabric was less
as compared to plain weave fabric.
Wrinkle resistant finishes limit the movement of fibre elements. This results in
reduced breaking strength of the fibre. Fibres with such finishes are more
susceptible to exceeding the fibre breaking strength under an applied force.
Wrinkle resistant finishes affect pilling performance of woven fabrics by decreasing
the ability of the fibre to move. This leads to decreased pilling which is always
desirable.
References
1) NISCAIR Online Periodicals Repository. Retrieved from :
http://nopr.niscair.res.in/bitstream/123456789/4391/1/IJFTR%2034(2)%20183-186.pdf
2) Can Y. , Akaydin M. , Turhan Y. & Ay E. Effect of wrinkle resistance finish on
cotton fabrics properties. Indian Journal of Fibre & Textile Research. Volume
34. June 2009 Retrieved from :
https://www.researchgate.net/publication/242148517_Effect_of_wrinkle_re
sistance_finish_on_cotton_fabric_properties
3) Lo & Yuen L. Wrinkle resistant finishes on cotton fabric. Hong Kong
Polytechnic University. Retrieved from : http://hdl.handle.net/10397/3568
4) Tusief MQ. Impact of various wrinkle free finishes on wrinkle recovery
property of Cotton fabric under different variables. Journal of Textile Science
& Engineering. Volume 4. Issue 4. Retrieved from :
https://www.omicsgroup.org/journals/impact-of-various-wrinkle-free-
finishes-on-wrinkle-recovery-property-of-cotton-fabric-under-different-
variables-2165-8064.1000160.php?aid=27693
5) Yang R.H. & Kan C.W. Effect of wrinkle free finishing of Cotton. Journal of
Engineered Fibers & Fabrics. Volume 10. Issue 3 – 2015. Retrieved from :
http://www.jeffjournal.org/papers/Volume10/V10I3(19)%20R.%20Yang.pdf
6) Datta C. , Behera J. , Hansda M. & Haldar S. Wrinkle recovery finishing for cellulosic
fabric. The Indian Textile Journal. Retrieved from :
http://indiantextilejournal.com/articles/FAdetails.asp?id=2635
7) Moghazy Y. E. Engineering Textiles : Integrating the Design & Manufacture of Textile
Products. Page 312. Elsevier publishers. Retrieved from :
https://books.google.co.in/books?id=B7GjAgAAQBAJ&pg=PA312&dq=effect+of+wrinkle+r
esistant+finish+different+fabrics&hl=en&sa=X&redir_esc=y#v=onepage&q=effect%20of%
20wrinkle%20resistant%20finish%20different%20fabrics&f=false
8) Adanur S. Wellington Sears Handbook of Industrial Textiles. Page 175. CRC publishers.
Retrieved from :
https://books.google.co.in/books?id=K8uCgQD7oNAC&pg=PA175&dq=effect+of+wrinkle+
resistant+finish+different+fabrics&hl=en&sa=X&redir_esc=y#v=onepage&q=effect%20of%
20wrinkle%20resistant%20finish%20different%20fabrics&f=false
9) Jones M.A. An annotated bibliography of cotton research. Page 17. Miscellaneous
publications. Issue 893. Retrieved from :
https://books.google.co.in/books?id=LRsuAAAAYAAJ&pg=PA17&dq=effect+of+wrinkle+re
sistant+finish+different+fabrics&hl=en&sa=X&redir_esc=y#v=onepage&q=effect%20of%2
0wrinkle%20resistant%20finish%20different%20fabrics&f=false
10) Gaikwad T.B. & Wasib A.I. Wrinkle free finish. Document. Ichalkarangi, Maharashtra.
D.K.T.E. Textile & Engg. Institute.
11) Mukthy A.A. & Azim A.Y. Effects of resin finish on Cotton blended woven fabrics.
International Journal of Scientific Engineering & Technology. Pages 983-990. Volume
No.3. Issue No.7. 1 July 2014.
12) Shenai V.A. Technology of Textile Finishing. Pages 168-190. 1995. Sevak Publications,
Bombay.
13) Nalankilli G. & Jayaprakasam S. Textile Finishing. Pages 41-55. S.S.M. Institute of
Textile Technology, Komarapalayam.