Ind ian Journa l of Fibre & Textile Research
Vol. 27. December 2002. pp. 393-390
Crease recovery of fabrics with air-jet textured weft yarns
A Mukhopadhyay"
Department of Tex til e Tec hn ology, The Technol og ical Institute of Textile & Sciences, Bhiwani 12702 1, Indi a
and
V K Kothari
Department of Textile Tec hnology, Indi an In stitute of Technology, New Delhi 11001 6. India
Receil'ed 1 AI/ gl/sl 2001; rn'iscd receil'ed al/d {lccepl('(114 Decelllber 200 1
The crease recovery of fabric s in relation to the direct ion of creasing. pick spacing, heat sClling and number of
filaments in air-jet textured weft ya rn has been inves tigated. With the increase in pick densit y, the warp-w ise CITJSe
reco very of air-jet texturcd yarn fabrics decreases and a reve rse trend is observed in weft direction . The tc xturcd yarn fabl'i cs
ex hibit much lowe r crease recovery than the correspo ndin g parelll ya rn fabrics. The ri ner filament textured yarn fabri cs
possess hi gher crease recovery than th e coarser filamcnt tex tured yarn fabric s. Heat selling improvcs th c overa ll crease
reco ve ry of fabri cs. Impro ve ment in crease reco ve ry is hi gher for texlllred yarn fabri cs . parliculad y in we ft direction. After
heat selling, the peak va lue or crease recovery occ urs at dilTerent biased direction .
Keywords : Air-jet te xtured ya rn . Crease recove ry, Heat-set fabri c. Pick den sit y
1 Introduction
The crease recovery behaviour of fabrics can be
quantified by the crease recovery angle which
indicates the ability of fabrics to recover from th e
imposed deformations and has a great practical
relevance. The above parameter is important for
eva luating the aesthetics and easy care performance of
apparel, and engineering fabrics for better appearance.
Earlier work highlighted the effect of fabric
0
.
I parameters 1'-,
Ileat settlllg
. I an d
constructlona
3
direction of testing on the fabric crease recovery
characteristics. Wrinkle recovery of fabric is strongly
intluenced by crease recovery . The present paper
reports the effcct of test direction , heat setting, pick
spacing and number of filaments in yarn cross-section
on the crease recovery of fabric s with air-jet textured
weft yarn s.
2 Materials and Methods
2.1 Materials
Pl ain woven fabric sa mples were prepared with
14.7 tex polyester-viscose (67:33) warp and nominal
"To whom all th e correspondence should be addressed.
Present address : Department of Texti le Engineering. Reg ional
Engineering Coll ege, Jala ndh ar 1440 II , Indi a.
Phone: 29330 1-02-03: Fax: 0091 -0181-293653:
E-mail: arunangshlu·ecj @redirrmail.com
end density of 36 ends/c m. Polyester flat filament
yarns differin g in number of filaments and the air-jet
tex tured yarns made therefro m were used as weft.
Two fully drawn multifilament polyester yarns of 70
denier (7.77 tex)l36 filaments and 70 denier (7.77
te x)172 filam ents were used as parent material for
producing two different textured yarn s. The yarns
were parallel end textured on Eltex AT/HS air-jet
texturing machine using the HemaJet with TIOO core
under the following texturing conditions:
Overfeed to jet
26.7 %
Air press ure
9 kglk lll '
Texturing speed
300 Ill/min
Wat er used per jet
I litre/h
Water pressure
2 kgUcm 2
Stabi Iizati on stretch
4.7 %
Stabili za tion hea ter temperature
180"C
Winding underfeed
0.7 %
The linear densities of the air-jet textured yarns
were 17.54 tex and 17.34 tex for coarser and finer
filament yarns respectively . The linear density of
doubled parent yarn of each type was sa me ( 15 .54
tex ). Four different pick den sities (24.4, 27.5 , 30.7
and 33.S picks/cm) were used on th e loom for eac h of
four types of weft yarn. The fabric s were heat-set on
Primatex stenter at ISO"C and 20 m/min speed with 3
% overfeed, allowing 5.1 % width-wi se shrinkage.
INDIAN 1. FIBRE TEXT. RES. , DECE MBER 2002
394
2.2 Methods
3 Results and Discussion
Th e crease recovery of all the fabrics was measured
at 5 different direction s with res pect to warp ( 0°,
22.5 °, 45 °, 67 .5° and 90°) usin g Shirley crease·
recovery tester following the British Standard 4 . The
mean values of 8 tests were taken in all the directions.
A rand o m sa mpl e was taken but th e se lvedges, piece
e nds a nd c reased or fold ed reg ion s were avoided. For
all fabrics, th e spec imens were conditioned and tested
in a standard testing atmosphere.
3.1 Effect of Pick Density
120
Table I and Figs 1& 2 show th at fo r a ll types of
fabric with ·th e increase in pick de nsity th e crease
recovery decreases in warp direction a nd in c reases in
weft directio n. In weft direction , the improv e me nt in
crease recovery with the increase in pi ck density is in
contradic tion w ith the earlier findingst2. During
creas ing in warp direc tion , the number of warp
threads which are s ubjected to bendin g deformation
r -- - - .- - - - - - - - - - -
--=l
----
150 r 140 -
130
..--.. In'
...... -- -.-
:00 120
'0
_____
_
...........-"~-----
~. 110
100 -
~
90
~
U
II
I
8"
~
--------" [IT
.__-
so 70
- -__
_
. - --
- --
~_
-
_
..
.-
---. GI'
_ _...... -
- - - - - . GT
T
60
50+-- - --
22
26
32
30
34
22
36
26
30
32
Pick Density, picks/e m
Grey
parent
Grey
tex tured
Hea t-set
pa rent
Hea t-sc t
te xtured
Nominal
pick den sit y
34
36
Fig.2 - E ffect of pick density 0 11 weft -w ise crease reco ve ry of
g rey a nd heat-set finer fi lament ya rn fab ri cs (G- Gre y. H Heat-set, P- Paren t, and T - Texwred )
Fig. 1 - Effec t of pick density o n warp-wise c rea se recove ry of
g rey and heat -set fin e r fi lame nt ya rn fabric s (G - Grey , H Hea t-se t, P - Parent , a nd T - Tex tured)
Material
-
28
Pi ck Densily, picks/em
Table I -
-
Crease recove ry va lues (in deg ) o f parent and tex tured ya rn woven fabri cs
Test d irec ti o n with respect to warp for
coa rse r filam ent fabr ic
picks/c lll
0°
24.4
27.5
Test direction w ith respec t to warp for
finer fil ament fab ric
22 .5°
45 °
67.5°
90°
0°
105.4
11 7.8
125.2
104.6
80.2
100.6
115.0
124.3
11 0.0
84 .0
30.7
96.0
11 3. 1
12 1. 8
112.8
33.8
95.6
110.2
115 .4
24.4
76.4
100.2
27.5
75 .6
30.7
74.2
33.8
22.5 °
45 °
67.5°
90°
101.1
11 2.2
12 1. 2
100.0
86.7
96 .2
110.0
120.5
104.2
89. 2
89 .6
94 .3
107 .0
115.2
104.6
90. 2
108. 6
90.2
93.2
98.7
106.3
95.4
9J.3
110.0
89.2
62.8
88 .8
106.2
11 0.9
95.3
7 1.'1
93.4
109 .8
92.4
66.6
86.6
100.2
115.0
96.0
72.5
94.4
103.2
92.7
69.2
81.2
98.7
109.3
90.6
73 .8
73.5
80.6
86.2
78.6
71. 2
74 .7
98.4
95 .8
86.2
76. 2
24.4
11 3.3
124 .2
134.4
136.0
120.2
108.4
120.2
13 1.2
138 . 1
128.4
27.5
109 .2
123.6
13 1.0
136.8
124.4
107.5
11 8.3
128 .3
139 .2
129 .3
30.7
108.6
12 1.4
129.2
137 .0
126.2
106. 1
116.2
126.2
139.3
132.4
33.8
107.2
11 8.2
126.4
138 . 1
13 1.4
104.2
117.5
11 3.2
14 1.2
136.7
24.4
97.8
104.6
119.5
124.2
106.0
105.7
11 2.4
123 .8
128. 1
11 3.5
27.5
90 .2
103.2
11 5.2
125.6
11 4.2
103. 2
109.7
122.7
129. 2
120.3
30.7
94.2
102. 3
114. 2
126.3
118.6
100. 1
112 .2
120.6
130.2
122.4
33.8
92.6
98.6
112.6
128.2
12 1. 6
98.2
107.4
120.2
130.3
127.6
MUKH OPADHYAY & KOTH ARI : CREASE RECOVERY OF FA BRICS
re mains mo re o r less same w ith th e inc rease in pi c k
de nsity. Th erefo re, decrease in crease recovery due to
increase in pi ck density is ma inl y attributed to
co nsequ ent increase in inte r- yarn fricti o n. On the
oth er hand , with the in crease in pi ck density the
improvement in crease reco ve ry in weft directi o n is
du e to the greater res istance to bendin g by th e hi g he r
number of weft threads. The above beha vio ur can a lso
be seen after heat setting .
It may be observed fro m T abl e 1 th at fabri c c rease
recovery vari es differentl y at othe r test directi o ns as
we ll. A t 22.5° and 45 ° o f c reas ing, th e c rease
recove ry dec reases g radu ally w ith th e increase in pi ck
density fo r all ty pes of fabri c, whe reas at 67.5 ° of
creas ing, th e crease reco ve ry g radu a ll y inc reases w ith
the pick density except at hi g h level of pi ck de nsity
(33.8 pi cks/cm ) in g rey fabri cs.
395
recovery IS lower fo r fin er fil a ment fabri c. As the
number of fil a me nts is hi g he r fo r a g ive n yarn lin ear
de nsity , it ca uses g reater fri cti o n at c rossove r po int s,
leading to lo wer crease recovery. Ho weve r, durin g
creas in g in weft directi o n as the number o f fil aments
in creases fo r fin e r fil ament fa bri c, th e load is shared
by mo re number o f fil ame nts, leadin g to better
recovery.
Unlik e in the above case, the crease recovery o f
tex tured yarn fabri c is hi g he r fo r fin er fil a ment ya rn
fa bri c wh e n th e recove ry is meas ured in wa rp
directi o n. Thi s is poss ibl y due to less tenden cy of yarn
fl atte nin g in case o f fin er fil ament tex tured ya rn ,
leading to less sharpe r crease and be tter crease
130 .,--
- - - - -- -
- --
-
- --
·- - - - - ,
120
3.2 Effed of Texturing
It may be observed from Tabl e
and Fi gs 1 & 2
th at th e textured yarn fabri c has lo we r crease recovery
th an the co rres po nding pare nt yarn fabric . Tex turin g
of fil a ments produ ces loops and entangle me nts, whi ch
result in greater fri cti o n at th e crossover po ints
leadin g to poor recovery. Further during we ft- wise
creasin g, g reate r stra in will be developed on th e
indi vidua l filame nt o f the e ntan g led co re of the
tex tured yarn , leading to lower crease recovery.
110
eO
i
"
GP2
100
8
90
~
80
~
~
~~
~
u
70
GT2
60
50+--------,------~-------.-----~
22.5
45
67.5
90
Test Dircc1ioll. del'.
3.3 Effed of Heat Setting
The crease reco very o f all types of heat-set fa bric is
always hi gher th an th at o f g rey fabri cs at all the
directio ns (T abl e I). Heat setting redu ces the in-built
stresses in the fil a ment to a large ex te nt. As the
crimped co nfi g urati o n has been set and the strains
prese nt initi all y get re laxed, the strain s de ve lo ped
d uring creas in g will be comparati ve ly lo wer, leadin g
to better crease recovery.
It is furth e r o bserved th at the impro vement in
crease recovery is mu ch hi gher in weft directi o n th an
in an y other direction. Thi s is ex pected as the we ft
mate ri al is co mposed of 100 % pol yeste r fi lament.
After heat settin g, th e diffe re nce between the crease
recovery of pare nt and correspo nding textured yarn s
red uces co nsiderabl y (Tabl e I and Fi gs I & 2). Th e
ex tent of improveme nt in crease recove ry due to heat
setting is diffe rent for di ffere nt mate rial s at differe nt
directions of creas ing .
3.4 Effect of Number of Filaments in Yarn
It is observed from T ab le I th at in case o f g rey a nd
heat-set pare nt yarn fabri cs, th e warp-wi se c rease
Fig.3 - Effect of test directi on on crease recovery of grey fabric s
with nominal pick de nsity of 30.7 picks/c m (G - Grey . H Heat-set. P- Parent, T - Tex tu red, 1 - Finer fil ament, and 2 Coarser fil ament )
150
I
t40
~ 1 30
}fi~~~
~
_____
"',,' 120
~
~ i lO
'
:
~k
~ IOO~
~
______-.-
~ -----_ _____ 111"1 _
J IT2
J.--
90
l'
80 .,
7o ~I------.------~------__,------~
22.5
45
67 .5
90
Test Direction. deg
Fig.4 - Effect of test direct-ion on crease recove ry of heat-SCI
fab rics with nominal pi ck dc nsit y of 30. 7 picks/c m (G - Grey. H
- Heat-set, P - Parent, T - Textured, 1 - Finer fil alllent. and
2 - Coarse r fil ament )
396
IN DI AN J. FIBR E T EXT. RES., DECEMB ER 2002
recovery. In all the oth er tes t directi ons, th e fin er
filament tex tured yarn fabri cs have hi gher crease
recove ry th an th e coa rser fil ament tex tured yarn
fabrics (Tabl e I and Fi gs 3 & 4) .
3.5 Effect of Test Direction
Tab le I and Fi gs 3 & 4 show th at th e crease
recove ry of grey fa brics first increases up to 45 ° and
thereafter it clec reases graduall y. During folding or
creasing in a bi ased direc ti on, part of th e bendin g is
transformed into torsional deformati on of the ya rn s.
Along with the torsional effec t, th e bucklin g of th e
y, rn causes an apprec iable redu cti on in strain level
with co nsequ ent increase in crease recovery. [n the
above case, the rate of decrease in crease recovery is
greater as co mpared to the rate of increase for th e
fa bric of lower pi ck density. At hi gher pick density
the rat e of clec rease is lowe r.
[t is observed fro m Fi gs 3 & 4 th at th e heat-set
fab ri c shows th e same trend as th at of grey bu t th e
reversal occurs at 67 .5° instead of 45 ° tes t directi on.
Thi s is du e to th e greater improvement of crease
recovery in weft directi on.
4 Conclusions
With th e increase in pick density, th e warp-w ise
crease recovery of air-j et tex tured yarn fabrics
dec reases, but th e trend is reversed in we ft directi on.
The crease recovery of tex tured yarn fa bri cs is mu ch
lower th an th at of the correspondin g parent ya rn
fabri cs . With the hi gher number of fil aments in the
tex tured ya rn , th e crease recovery is hi gher for all
types of fabri c.
Heat setti ng improves th e overall crease recovery
of fabri cs. Howeve r, th e imp rove ment is hi gher fo r
tex tured ya rn fab ri cs, parti cul arl y in weft direc ti on.
After heat settin g, the peak valu e of crease recovery
occ urs at di fferent biased directi on.
References
M ims N M & Rossi ter ED. J Tcxt /llst. -1 7 ( 1956) 708.
2 Steele R, J Tl'l t /II.1't, S3 ( 1962) 7.
3 Sengupta A K, De D & Sarkar B P. Text Res J. 42 ( 1972 ) 268.
or
4 Rec ove ry
fabric s fro m creas ing. BS 3036. BS NOIII/hook //
(Briti sh St:tndarcl lnstiluli on, Lond on). 1974.