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CHAPTER 6
EFFECT OF FABRIC STRUCTURE AND STITCH LENGTH
ON THE DIMENSIONAL PROPERTIES OF SPUN
VISCOSE SINGLE JERSEY KNITTED FABRICS
6.1 INTRODUCTION
The overall dimensional change in weft knitted fabrics during
washing is a significant factor to the ultimate consumer of a garment. The
magnitude of weft knitted fabric dimensional stability, not only depends on a
combination of fibre characteristics, yarn factors, stitch length, knitting
tension, washing and drying methods and also the fabric structure. The
dimensional properties of plain, rib, half cardigan, interlock weft knitted
structures made with wool were extensively investigated by Knapton et al
(1968) and stated that, fabric dimensions in a relaxed state are dependent
upon yarn, fabric and machine variables.
Nutting and Leaf (1964) mentioned that, there are many different
types of weft knitted fabric constructions (plain, rib, interlock, etc.), each
possessing its own geometrical relations. A number of these structures have
been studied and their geometries were investigated. Earlier studies were
conducted on a wide variety of plain knitted fabrics using cotton, wool, orlon
and nylon for the change in the geometrical parameters during different stages
of relaxation by Munden (1959) and Doyle (1953). Kane et al (2007)
mentioned that, combination order of knit-tuck stitches played an important
role in all the dimensional and physical properties.
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However, there is a paucity of research on the effect of fabric structure
on the dimensional properties of spun viscose single jersey knitted fabrics. Most
published work has involved simple structure, but the present analysis is
concerned with an exploration of the possibilities of extending this type of work
to include structures involving tucking. The single jersey knitted fabrics
produced with tuck stitches shows thicker structure, less extensible and wider.
The present study is to analyze the effect of fabric structure and stitch length on
dimensional properties of spun viscose single jersey knitted fabrics under dry,
wet and fully relaxation states. The effect of fabric structure (Plain, Pique and
Lacoste) and stitch length on the dimensional properties of spun viscose singlejersey knitted fabrics under dry, wet and fully relaxation states were studied.
6.2 MATERIALS AND METHODS
In order to study the influence of fabric structure, stitch length and
relaxation treatments on dimensional properties of spun viscose single jersey
knitted fabric, three different fabric structure such as Plain, Pique and Lacoste
were used. The details of the spun viscose single jersey knitted fabrics
production methods used for the study are given in section 3.2.3.2. The
details of the relaxation treatments such as dry, wet and fully relaxation used forthe Plain, Pique and Lacoste single jersey knitted fabrics are given in section 3.2.4.
6.3 RESULTS AND DISCUSSION
6.3.1 Effect of Fabric Structure and Stitch Length on DimensionalCharacteristics
The dimensional properties of Plain, Pique and Lacoste single
jersey knitted fabrics made from 14.8 tex viscose spun yarns with three
different stitch lengths have been investigated under three different conditions
such as dry, wet and fully relaxation. The dimensional characteristics of the
Plain, Pique and Lacoste single jersey knitted fabrics have been analyzed andthe results are tabulated in Table 6.1.
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6.3.1.1 Courses and wales
The effect of fabric structure, stitch length and relaxation
treatments on courses per centimeter and wales per centimeter of the plain,
pique and lacoste single jersey knitted fabrics are shown in Figures 6.1 and
6.2. The values of courses per centimeter and wales per centimeter are plotted
against the stitch length for plain, pique and lacoste spun viscose single jersey
knitted fabrics. It is noticed that for the different stages of relaxation, course
per centimeter and wales per centimeter and the stitch length are linearly
related.
Effect of fabric structure and stitch length of courses per centimeter
of the weft knitted fabrics is significant at wet and fully relaxed states.
F observed > F critical on F (2, 4) = 158.39 (for stitch length) and 8.59
(for fabric structure) P < 0.05 in wet relaxed fabric. F observed > F critical on
F (2, 4) = 498.30 (for stitch length) and 18.44 (for fabric structure) P < 0.05 in
fully relaxed fabric. It is noticed that, courses per centimeter variations of
plain, pique and lacoste structures gradually increased under dry and wet
relaxation treatments and increases in a fully relaxed state. It is also noticed
that, course per centimeter of lacoste structure is reasonably higher than plain
and pique single jersey knitted fabrics. The possible reason observed is, the
fabric width is increased because tuck loops pull the held loops downward
and increases course density of lacoste structure.
Effect of fabric structure and stitch length on wales per centimeter
of the single jersey knitted fabric is significant at wet and fully relaxed state.
F observed > F critical on F (2, 4) = 23.13 (for stitch length) and 35.13
(for fabric structure) P < 0.05 in wet relaxed fabric. F observed > F critical on
F (2, 4) = 39.22 (for stitch length) and 37 (for fabric structure) P < 0.05 in
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fully relaxed fabric. It is noticed that, wales per centimeter variations of plain,
pique and lacoste structures gradually increased under dry and wet relaxation
treatments and increases in a fully relaxed state. It is also noticed that, wales
per centimeter of lacoste structure is reasonably lower than plain and pique
single jersey knitted fabrics. It is observed that, stitch length and fabric
structures significantly affect the courses per centimeter and wales per
centimeter of the fully relaxed spun viscose single jersey knitted fabrics. This
was due to a combination of knit-tuck stitches. Tuck loop reduces fabric
length and lengthwise elasticity because the higher yarn tension on the tuck
and held loops cause them to pull the yarn from adjacent knitted loops making
them smaller.
Figure 6.1 Effect of fabric structure and stitch length on courses per
centimeter of spun viscose single jersey knitted fabrics
10121416182022242628
0.2450.2750.295 0.2450.2750.295 0.2450.2750.295
Plain Pique Lacoste
DryWetFully
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Figure 6.2 Effect of fabric structure and stitch length on wales per
centimeter of spun viscose single jersey knitted fabrics
6.3.1.2 Stitch density
The effect of fabric structure, stitch length and relaxation
treatments on the stitch density of the plain, pique and lacoste spun viscose
single jersey knitted fabrics are shown in Figure 6.3. The values of stitch
density are plotted against the stitch length for plain, pique and lacoste single
jersey knitted fabrics. It is noticed that for the different stages of relaxation,
stitch density and the stitch length are linearly related. Effect of fabric
structure and the stitch length on stitch density of the spun viscose single
jersey knitted fabrics is significant at dry, wet and fully relaxed states.
F observed > F critical on F (2, 4) = 344.78 (for stitch length) and 14.10
(for fabric structure) P < 0.05 in dry relaxed fabric. F observed > F critical on
F (2, 4) = 522.86 (for stitch length) and 33.76 (for fabric structure) P < 0.05 in
wet relaxed fabric. F observed > F critical on F (2, 4) = 432.05 (for stitch
length) and 10.49 (for fabric structure) P < 0.05 in fully relaxed fabric.
10
12
14
16
18
0.245 0.275 0.295 0.245 0.275 0.295 0.245 0.275 0.295
Plain Pique Lacoste
DryWetFully
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Figure 6.3 Effect of fabric structure and stitch length on stitch density
of spun viscose single jersey knitted fabrics
The use of stitch density or number of loops per unit area of fabric
is preferred, since it is less affected by distortion. Courses per centimeter and
wales per centimeter are directly related to the stitch densities of the plain,
pique and lacoste spun viscose single jersey knitted fabrics. Stitch density is
directly responsible for determining the dimensional stability of the knitted
fabrics. It is observed that, the number of tuck stitches of lacoste structures
gives greater stability and shape retention properties and makes the fabric
dimensionally stable compared to that of plain and pique fabrics.
6.3.1.3 Tightness factor
Figure 6.4 shows the effect of fabric structure and stitch length on
tightness factor variations of the dry, wet and fully relaxed plain, pique and
lacoste spun viscose single jersey knitted fabrics. Effect of fabric structure
and stitch length on tightness factor of spun viscose single jersey knitted
180
200
220
240
260
280
300
320
340
360
380
400
0.245 0.275 0.295 0.245 0.275 0.295 0.245 0.275 0.295
Plain Pique Lacoste
DryWetFully
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fabric is significant at dry, wet and fully relaxed states. F observed > F critical
on F (2, 4) = 1719.55 (for stitch length) and 15.42 (for fabric structure)
P < 0.05 in dry relaxed fabric. F observed > F critical on F (2, 4) = 508.54
(for stitch length) and 8.72 (for fabric structure) P < 0.05 in wet relaxed
fabric. F observed > F critical on F (2, 4) = 3199.13 (for stitch length) and
71.47 (for fabric structure) P < 0.05 in fully relaxed fabric.
The tightness factor of the plain, pique and lacoste spun viscose
single jersey knitted fabrics increase with relaxation steps. It is observed that,
fabric structure influences the tightness factor of spun viscose single jersey
knitted fabrics. This shows that during the relaxation steps, fabric structure
influence the release of internal stress in the spun viscose single jersey knitted
fabrics. It is also observed that, lacoste spun viscose single jersey knitted
fabric shows higher tightness factor values compared to that of plain and
pique fabrics.
Figure 6.4 Effect of fabric structure and stitch length on tightness
factor of spun viscose single jersey knitted fabrics
1111.5
1212.5
1313.5
1414.5
1515.5
1616.5
17
0.2450.2750.295 0.2450.2750.295 0.2450.2750.295
Plain Pique Lacoste
DryWetFully
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6.3.1.4 Areal density
Figure 6.5 shows the effect of fabric structure and stitch length on
areal density variations of the dry, wet and fully relaxed plain, pique and
lacoste spun viscose single jersey knitted fabrics. Effect of fabric structure
and stitch length on areal density of plain, pique and lacoste spun viscose
single jersey knitted fabric is significant at dry, wet and fully relaxed state.
F observed > F critical on F (2, 4) = 286.3 (for stitch length) and 24.91
(for fabric structure) P < 0.05 in dry relaxed fabric. F observed > F critical on
F (2, 4) = 471.73 (for stitch length) and 75.47 (for fabric structure) P < 0.05 in
wet relaxed fabric. F observed > F critical on F (2, 4) = 300.58 (for stitch
length) and 91.51 (for fabric structure) P < 0.05 in fully relaxed fabric.
The fabric weight is plotted against the stitch length for the plain,
pique and lacoste spun viscose single jersey fabrics under dry, wet and fully
relaxed states. It is observed that the areal density of the plain, pique and
lacoste spun viscose single jersey fabrics are linearly related to the stitch
length. However, lacoste spun viscose single jersey fabric shows higher areal
density with decreasing stitch length compared to that of plain and pique
fabrics. A possible reason is that, due to more tuck stitches per unit area
compared to that of plain and pique fabrics. It was observed that the knit tuck
combination showed higher areal density value than plain and pique fabrics.
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Figure 6.5 Effect of fabric structure and stitch length on areal density
of spun viscose single jersey knitted fabrics
6.3.1.5 Spirality
Figure 6.6 shows the effect of fabric structure and stitch length on
spirality variations of the dry, wet and fully relaxed plain, pique and lacoste
spun viscose single jersey knitted fabrics. Effect of fabric structure and stitch
length on spiratlity of spun viscose single jersey knitted fabric is significant at
dry, wet and fully relaxed state. F observed > F critical on F (2, 4) = 27.25
(for stitch length) and 192.25 (for fabric structure) P < 0.05 in dry relaxed
fabric. F observed > F critical on F (2, 4) = 30.06 (for stitch length) and 57.81
(for fabric structure) P < 0.05 in wet relaxed fabric. F observed > F critical on
F (2, 4) = 51.86 (for stitch length) and 191.77 (for fabric structure) P < 0.05 in
fully relaxed fabric.
70
80
90
100
110
120
130
140
150
0.245 0.275 0.295 0.245 0.275 0.295 0.245 0.275 0.295
Plain Pique Lacoste
Dry
WetFully
80
Figure 6.6 Effect of fabric structure and stitch length on spirality of
spun viscose single jersey knitted fabrics
Spirality of the dry, wet and fully relaxed plain, pique and lacoste
spun viscose single jersey knitted fabrics increase with increase in stitch
length. It is observed that, plain, pique and lacoste single jersey knitted fabrics
knitted with more tightness factor shows lower spirality. The possible reason
is due to less loop and yarn movement within the structure. It is also observed
that, lacoste single jersey knitted fabrics shows lower spirality value
compared to that of plain and pique fabrics with decrease in loop length. The
lower spirality indicates that, the lacoste single jersey knitted fabrics shows
better dimensional stability compared to that of plain and pique fabrics.
4
4.5
5
5.5
6
6.5
7
7.5
8
0.245 0.275 0.295 0.245 0.275 0.295 0.245 0.275 0.295
Plain Pique Lacoste
Dry
WetFully
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6.3.2 Effect of Fabric Structure and Stitch Length on Dimensional
Constants
The effect of fabric structure, stitch length and relaxation
treatments on dimensional constants of plain, pique and lacoste spun viscose
single jersey knitted fabrics have been analyzed and the results are tabulated
in Table 6.2. Table 6.2 shows that, relaxation treatments brought about an
increase in the numerical values of Kc, Kw and Ks is caused by a change in
the loop shape as fabric passed from dry relaxed state to the more stable fully
relaxed state. Effect of fabric structure and stitch length on Kc, Kw and Ks is
significant at fully relaxed fabric. F observed > F critical on F (2, 4) = 25.67
(for stitch length) P < 0.05 in fully relaxed fabric. F observed > F critical on
F (2, 4) = 42.30 (for stitch length) and 47.72 (for fabric structure) P < 0.05 in
fully relaxed fabric. F observed > F critical on F (2, 4) = 7.72 (for stitch
length) and 10.44 (for fabric structure) P < 0.05 in fully relaxed fabric.
The length and width dimensions of the plain, pique and lacoste
single jersey knitted fabrics are dependent on the tightness factor. Table 6.2
indicates that, the difference in the values of Kc, Kw and Ks of all the fabrics
are noticeable but small. Table 6.5 indicates that, the variations in Kc, Kw, Ks
and loop shape factor of dry, wet and fully relaxed lacoste single jersey
knitted fabric is small compared to that of plain and pique single jersey
knitted fabrics. This is evident that, the lacoste single jersey knitted fabrics
shows better dimensional stability compared to that of plain and pique spun
viscose single jersey knitted fabrics.
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Table 6.2 Dimensional constants of the dry, wet and fully relaxed spun
viscose plain, pique, lacoste single jersey knitted fabrics
Stitch lengthlevel
NominalStitchlength(mm)
Relaxationstates Kc Kw Ks Kl
Plain
2.45Dry 5.54 3.72 20.62 1.49Wet 5.59 3.86 21.59 1.45Fully 5.66 3.96 22.43 1.43
2.75Dry 5.03 3.79 19.10 1.33Wet 5.14 4.05 20.83 1.27Fully 5.32 4.16 22.11 1.28
2.95Dry 5.04 3.78 19.05 1.34Wet 5.08 4.18 21.19 1.21Fully 5.33 4.26 22.71 1.25
Pique
2.45Dry 5.54 3.26 18.10 1.69Wet 5.56 3.49 19.48 1.59Fully 5.80 3.66 21.24 1.59
2.75Dry 5.05 3.44 17.37 1.46Wet 5.37 3.90 20.94 1.37Fully 5.43 3.99 21.69 1.36
2.95Dry 5.05 3.39 17.12 1.49Wet 5.21 3.86 20.12 1.35Fully 5.47 4.05 22.15 1.35
Lacoste
2.45Dry 5.57 3.24 18.04 1.71Wet 5.59 3.27 18.27 1.71Fully 5.85 3.46 20.26 1.68
2.75Dry 5.11 3.37 17.25 1.52Wet 5.27 3.63 19.14 1.45Fully 5.34 3.73 19.94 1.43
2.95Dry 5.34 3.31 17.64 1.61Wet 5.55 3.69 20.47 1.50Fully 5.61 3.93 22.08 1.43
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Table 6.3 Dimensional constants values of the spun viscose plain
knitted fabrics
Relaxationstates
Kc Kw Ks Kl
Dry 5.20 + 0.291 3.76 + 0.142 19.58 + 0.889 1.39 + 0.109
Wet 5.26 + 0.282 4.03 + 0.160 21.20 + 0.580 1.31 + 0.120
Fully 5.44 + 0.193 4.12 + 0.152 22.42 + 0.495 1.32 + 0.096
Table 6.4 Dimensional constants values of the spun viscose pique
knitted fabrics
Relaxationstates
Kc Kw Ks Kl
Dry 5.21 + 0.283 3.36 + 0.092 17.52 + 0.503 1.55 + 0.101
Wet 5.38 + 0.180 3.75 + 0.120 20.18 + 0.526 1.44 + 0.110
Fully 5.57 + 0.175 3.89 + 0.106 21.69 + 0.455 1.43 + 0.083
Table 6.5 Dimensional constants values of the spun viscose lacoste
knitted fabrics
Relaxationstates
Kc Kw Ks Kl
Dry 5.34 + 0.230 3.30 + 0.065 17.64 + 0.400 1.62 + 0.100
Wet 5.47 + 0.174 3.52 + 0.103 19.29 + 0.420 1.44 + 0.107
Fully 5.60 + 0.155 3.71 + 0.092 21.69 + 0.401 1.43 + 0.050
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6.3.3 Effect of Fabric Structure, Yarn Shrinkage and Stitch Length
on Dimensional Changes
The effects of fabric structure and stitch length on lengthwise,
widthwise and area-wise dimensional changes of plain, pique and lacoste
spun viscose single jersey knitted fabrics have been analyzed and the results
are tabulated in Table 6.6. It is observed that, lengthwise, widthwise and
area-wise dimensional changes of the plain, pique and lacoste spun viscose
single jersey knitted fabrics increases with fabric tightness as shown in
Table 6.6.
Table 6.6 Dimensional changes of fully relaxed plain, pique and lacoste
spun viscose single jersey knitted fabrics
Sample
NominalStitchlength
(mm)
Tightnessfactor
( tex1/2
cm-1 )
Wet yarnshrinkage
(%)
Lengthwise
changes
(%)
Widthwise
changes
(%)
Area wise
dimensionalchanges
(%)
Plain
2.45 16.02 1.043 10.28 15.62 24.22
2.75 14.25 1.043 8.65 11.59 20.23
2.95 13.36 1.043 6.62 8.55 13.41
Pique
2.45 16.30 1.043 8.64 14.36 21.33
2.75 14.25 1.043 6.39 10.40 18.5
2.95 13.49 1.043 6.2 7.3 12.73
Lacoste
2.45 16.44 1.043 7.75 14.31 19.21
2.75 14.63 1.043 6.07 10.05 18.21
2.95 13.49 1.043 6.01 6.50 10.03
85
Fabric structure and stitch length significantly influences the
dimensional changes of plain, pique and lacoste spun viscose single jersey
knitted fabrics. F observed > F critical at F (2, 4) = 14.28 (for stitch length)
and 7.80 (for fabric structure) P < 0.05, for lengthwise dimensional changes
of the plain, pique and lacoste single jersey knitted fabrics. F observed > F
critical at F (2, 4) = 841.34 (for stitch length) and 45.40 (for fabric structure)
P < 0.05, for widthwise dimensional changes of the plain, pique and lacoste
single jersey knitted fabrics. F observed > F critical at F (2, 4) = 86.54
(for stitch length) and 10.74 (for fabric structure) P < 0.05, for areawise
dimensional changes of the plain, pique and lacoste single jersey knitted
fabrics. Yarn shrinkage also significantly influences the dimensional changes
of plain, pique and lacoste spun viscose single jersey knitted fabrics. Table
6.6 shows that, lengthwise, widthwise and areawise dimensional changes of
lacoste single jersey knitted fabrics is noticeably small than plain and pique
fabrics. This indicates that, fabric structure is also one of the responsible
factors for the dimensional changes of single jersey knitted fabrics. The
lacoste fabrics show better dimensional stable structure due to knit tuck
combination of the structure.
6.4 CONCLUSIONS
The study analyses the effect of fabric structure, stitch length and
relaxation treatments on the dimensional characteristics, dimensional
constants and dimensional changes of the plain, pique and lacoste spun
viscose single jersey knitted fabrics. The courses per centimeter, wales per
centimeter, stitch density and areal density of the fully relaxed plain, pique
and lacoste spun viscose single jersey knitted fabrics are found to be inversely
proportional to the stitch length and significantly influenced by the stitch
length and fabric structure. Lacoste fabrics show higher areal density as
compared with plain and pique fabrics. The result shows that the structural
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differences in the fabric play a large part in determining the dimensions of
plain, pique and lacoste spun viscose single jersey knitted fabrics.
Tightness factor and spirality of the plain, pique and lacoste single
jersey knitted fabrics significantly influenced by the stitch length and fabric
structure. The single jersey knitted fabrics made from lacoste structure shows
lower spirality as compared with plain and pique fabric. The lower spirality
indicates that, the lacoste single jersey knitted fabrics shows better
dimensional stability compared to that of plain and pique fabric.
It is also observed that the difference in the values of Kc, Kw of all
the plain, pique and lacoste spun viscose single jersey knitted fabric is
noticeable but small. The variations in Kc, Kw, Ks and loop shape factor of
the lacoste single jersey knitted fabric is small compared to that of the plain
and the piques single jersey knitted fabrics. This is evident that, the lacoste
spun viscose single jersey knitted fabrics shows better dimensional stability
compared to that of plain and piques fabric.
The lacoste single jersey knitted fabric has shown greater
advantages over the plain and the pique single jersey knitted fabrics. Based on
the test results, due to knit tuck combination lacoste structure exhibited better
dimensional properties made with similar count and stitch length compared to
that of plain and pique fabrics.
