**3. Experimental results**

The structural properties of denim fabrics and test results are illustrated in **Tables 4** and **5**, respectively.


**Table 4.** Structural properties of denim fabric samples.

#### **3.1. Breaking force and elongation**

*2.2.2. Statistical analysis*

28 Engineered Fabrics

**3. Experimental results**

**Fabric type Filament** 

Filament core-spun denim

Co/PET/elastane Dual core-spun denim **fineness (dtex)**

**Table 4.** Structural properties of denim fabric samples.

respectively.

Co/PET

In statistical analysis, multivariate analysis of variance (MANOVA) was achieved at 95% confidence interval by means of SPSS package program to determine whether there was statistically significant effect of the filament fineness, and elastane draft on denim fabric breaking force, breaking elongation, static tear force, elasticity, wicking rate and water absorption rate. The evaluated independent parameters were used as weft yarn in the denim fabric production

The structural properties of denim fabrics and test results are illustrated in **Tables 4** and **5**,

**Fabric weight (g/m2 )**

**Fabric thickness (mm)**

3.05 — 320 0.71 29.8 22.4 1.15 — 320 0.74 29.6 22.8 0.57 — 320 0.68 29.8 22.8 0.33 — 330 0.70 29.8 22.4

3.05 2.9 342 0.83 32.4 22.8 1.15 2.9 355 0.81 32.6 22.8 0.57 2.9 345 0.83 33 22.8 0.33 2.9 352 0.79 32.4 22.8 3.05 3.2 352 0.83 30.6 22.8 1.15 3.2 351 0.80 32.8 22.8 0.57 3.2 350 0.81 32.8 22.8 0.33 3.2 357 0.83 32.6 23.2 3.05 3.5 355 0.84 33.4 22.8 1.15 3.5 360 0.83 33 22.8 0.57 3.5 359 0.84 33 22.8 0.33 3.5 360 0.84 33 22.8 3.05 3.8 356 0.83 30.8 22.8 1.15 3.8 354 0.84 33.4 22.8 0.57 3.8 359 0.82 33.4 22.8 0.33 3.8 365 0.82 33.6 22.8

**Warp density (ends/cm)**

**Weft density (picks/cm)**

**Elastane draft**

100% Co denim — — 310 0.68 29.6 22

so all response variables were analyzed in weft direction as well.

To advance the comfort performance of the denim fabrics during body movement, dual core-spun yarns including elastane that provide higher elasticity and recovery are preferred. However, this advantage brings a disadvantage together and it leads to decrease in tensile strength of denim fabrics [30, 37]. The tensile test outcomes of the presented study is illustrated in **Figure 7** the breaking force of denim fabrics in weft wise composed of 100% Co, filament core-spun yarns and dual core-spun yarns.

It was clearly seen in **Figure 7** that denim fabrics made from filament core-spun yarns have the higher breaking forces than both 100% Co and dual core-spun denims. The highest breaking force was detected at 0.33 dtex filament core-spun denim fabric, this result is attributed to the fact that more filaments in the yarn cross-section can provide more resistance against tensile force. When the breaking forces of dual core-spun denim fabrics are taken into consideration in terms of effect of elastane draft, it is observed that the breaking force of samples with conventional firmament have increasing trend by increasing elastane draft. However, the fabric samples with micro fineness filament have decreasing trend with the elastane draft increase. Since increasing the elastane draft leads to decrease of elastane ratio within the fabric increase and so increase in breaking force of the fabric. However, this result is not clearly seen for dual core-spun denim fabrics due to involving both PET filament and elastane.

The breaking elongation of denim fabrics are shown in **Figure 8**. Elastane content contributes the elongation of the denim fabrics and this situation is clearly observed among the all fabric samples. Elongation directly affects the elasticity properties of the denim fabrics this is why elastane is used. The lowest breaking elongation was obtained with 100% Co denim fabric without both filament and elastane. When the denim fabrics made from filament core-spun yarns are investigated, it is seen that 3.05 dtex filament core-spun denim fabrics has the highest breaking elongation value and breaking elongation values of all filament core-spun denim fabrics are similar. From these results, it can be revealed that filament core part contributes strength of the fabric with an acceptable elongation value.

It can be possible to see how dominant the effect on the denim fabric elongation performance of the elastane draft ratio is. It is observed that with the increase of the elastic draft ratio, the breaking elongation of the fabric increases. This situation may be attributed to the fact that higher elastane draft may probably leads to increase in cohesion forces between filament, elastane and Co, and so breaking elongation can probably increase. Hereby, it can be said that elastane represents a large majority of the extensible part of fabric under the tensile force. In terms of filament fineness parameter of dual core-spun denim fabrics, it can be said that breaking elongation varies from 38.18 to 44.08%. The predominant elasticity property of elastane makes it difficult to see the effect of filament fineness in **Figure 8**, however, with statistical analysis effects can be examined in detail.

#### **3.2. Static tear force**

Static tear force in weft direction of denim fabric samples are illustrated in **Figure 9**.

According to tear force values, it is seen that 100% Co denim fabric has lower value than that of denim fabrics containing both filament and dual core-spun yarns. On the other hand, PET


**Table 5.**

Test results of denim fabric samples.

**Figure 7.** Weft wise breaking force of denim fabrics.

Denim Fabrics Woven with Dual Core-Spun Yarns http://dx.doi.org/10.5772/intechopen.80286 31

**Figure 8.** Weft wise breaking elongation of denim fabrics.

**Figure 9.** Weft wise static tear force of denim fabrics.

**Figure 7.** Weft wise breaking force of denim fabrics.

**Figure 8.** Weft wise breaking elongation of denim fabrics.

**Figure 9.** Weft wise static tear force of denim fabrics.

**Fabric type** 100% Co denim

Co/PET

3.05

—

1372.94

864.41

26.16

26.08

56.96

47.29

41.98

78.02

0.0524

0.0500

23.72

Filament corespun denim

1.15

0.57

0.33

Co/PET/elastane

3.05

2.9

1604.25

739.35

32.21

39.39

56.90

42.93

51.61

91.62

0.0506

0.0511

21.98

Dual core-spun

1.15 0.57 0.33 3.05 1.15 0.57 0.33 3.05 1.15 0.57 0.33 3.05 1.15 0.57 0.33

> **Table 5.**

Test results of denim fabric samples.

3.8

1574.92

784.28

31.58

43.23

53.96

47.39

50.40

90.38

0.0489

0.0474

28.07

3.8

1572.50

779.58

31.80

44.00

53.35

46.64

50.12

90.82

0.0300

0.0507

21.13

3.8

1547.79

792.34

32.23

42.47

54.81

48.49

46.89

91.24

0.0448

0.0485

28.47

3.8

1611.52

760.10

31.48

44.08

55.93

44.28

39.53

89.85

0.0365

0.0478

17.34

3.5

1632.86

777.56

32.33

41.67

55.07

46.27

53.75

90.76

0.0411

0.0457

29.30

3.5

1465.46

794.11

31.46

42.81

54.44

46.64

52.70

89.59

0.0461

0.0433

20.72

3.5

1658.09

778.34

32.87

41.44

53.77

47.73

52.76

90.17

0.0472

0.0463

24.92

3.5

1606.22

763.32

32.59

41.81

55.60

45.27

55.29

86.88

0.0487

0.0463

16.67

3.2

1586.84

801.25

33.42

41.42

55.36

48.70

52.58

89.51

0.0385

0.0480

26.18

3.2

1529.27

801.60

32.22

41.37

55.20

50.70

55.47

89.82

0.0333

0.0439

19.23

3.2

1327.06

801.72

31.17

41.49

54.43

49.58

55.09

87.97

0.0426

0.0474

25.01

3.2

1493.31

764.48

31.05

40.96

55.50

45.68

54.31

88.35

0.0480

0.0489

20.04

2.9

1581.12

799.83

32.96

38.67

55.92

49.44

53.03

87.18

0.0481

0.0485

29.24

2.9

1419.95

809.82

30.95

38.43

55.70

48.46

55.51

92.40

0.0467

0.0502

22.15

2.9

1533.54

781.09

32.15

38.18

55.42

48.84

52.55

92.37

0.0457

0.0509

26.30

denim

—

1335.22

888.84

26.98

25.45

56.33

50.50

43.33

80.34

0.0498

0.0444

22.16

—

1441.81

832.33

28.51

24.33

57.82

47.78

47.48

80.84

0.0317

0.0472

21.30

—

1403.24

831.55

24.23

24.77

57.60

47.86

47.50

77.68

0.0419

0.0469

21.28

—

—

1321.89

753.86

25.70

21.44

31.85

35.63

35.85

56.63

0.0496

0.0417

10.14

**Filament** 

**Elastane** 

**Breaking force (N)**

**Breaking** 

**Static tear force** 

**Elastic recovery** 

**Vertical wicking** 

**Water** 

**absorption (%)**

30 Engineered Fabrics

**rate (mm/s)**

**elongation (%)**

**(N)**

**(%)**

**fineness (dtex)**

**draft**

**Warp**

**Weft**

**Warp**

**Weft**

**Warp**

**Weft**

**Warp**

**Weft**

**Warp**

**Weft**

**—**

filaments from conventional to micro fineness contribute static tear force of denim fabrics except 0.57 dtex microfilament containing filament core-spun denim fabric. PET filament with 0.57 dtex filament fineness has the lowest breaking strength and so it can be said that filament properties affect the denim fabric properties as well. In addition, static tear force increases until 3.2 elastane draft ratio for all dual core-spun denim fabric types except 0.33 dtex filament containing dual core-spun denim fabric. Then, it is observed that after 3.2 draft value the increase in elastane draft effects static tear force negatively. Static tearing action leads to as the broken of the yarns individually or group. Hereby, increasing the elastane draft contributes tear force until 3.2 draft value because of the rising Co content. Furthermore, PET filament with fine and micro fineness contribute the tearing performance of the denim fabrics, because of the higher number of filament in the core of the dual core-spun yarns acts more resistance to break. This result can be explained with higher number of filament in the core of the dual core-spun yarns providing more resistance to break.

#### **3.3. Elastic recovery**

During usage of the denim should stretch freely in accordance with body movements especially at knee and should retain its original shape without any deformation after stretching. So that capability of extension and recovery of denim after repeated loadings is very important characteristics [38]. Higher the number of the loadings can contribute to life assessment in accordance with evaluating the fabric performance. Different from the test standard, 50 cycle loadings were carried out in order to evaluate elastic recovery of denim samples rather than 5 of cyclic loadings. Elongation after 50 cyclic loading and un-recovered elongation after 60 min recovery period were estimated according to Eqs. (1) and (2), respectively in accordance with BS EN 14704-1. Elongation, *S*, expressed as percentage:

$$S = \frac{E - L}{L} \ast 100\tag{1}$$

In terms of elastic recovery value of denim fabrics, pure Co denim has the lowest stretchability properties. The presence of elastane contributes to elastic recovery with a high value approximately 85–90%. Dual core-spun denim fabrics have also higher elastic recovery than filament core-spun fabrics. In general it can be said that increase in elastane draft also increases the elastic recovery except 2.9 elastane draft. It is seen that denim fabrics have the highest elastic

Denim Fabrics Woven with Dual Core-Spun Yarns http://dx.doi.org/10.5772/intechopen.80286 33

The wicking rate measurements in mm/s are presented in **Figure 11**. Weft wise wicking rate obtained for pure Co denim is lower than vertical filament core-spun denims. Vertical wicking rate of the filament core-spun denim fabrics decreases from 3.05 to 0.33 dtex. Since filaments are in the core part of the yarn, capillary transfer of water may not be fully observed during the period of time. This situation can be observed at the rest of the denim fabrics with different draft ratio. On the other hand, in general, the effect of the elastane draft can be seen

recovery at 2.9 elastane draft of 3.05, 1.15 and 0.57 dtex dual core-spun yarns.

**3.4. Wicking rate**

**Figure 10.** Weft wise elastic recovery of denim fabrics.

**Figure 11.** Weft wise wicking rate of denim fabrics.

where: *E* = extension (mm) at maximum force on the 50th cycles, *L* = initial length (mm).

Un-recovered elongation, *C*, expressed as percentage:

$$C = \frac{Q - P}{P} \ast 100\tag{2}$$

where: *Q* = distance between applied reference marks (mm) after a specified recovery period, *P* = initial distance between applied reference marks (mm).

From Eqs. (1) and (2) elastic recovery of fabric can be expressed as following Eq. (3).

$$R = \frac{S - C}{S} \ast 100\tag{3}$$

**Figure 10** displays weft wise elastic recovery of denim fabrics after waiting 60 min recovery period. It can be said that both filament and elastane improve stretchability and recovery properties of the denim fabrics when compared with pure Co ones.

In terms of elastic recovery value of denim fabrics, pure Co denim has the lowest stretchability properties. The presence of elastane contributes to elastic recovery with a high value approximately 85–90%. Dual core-spun denim fabrics have also higher elastic recovery than filament core-spun fabrics. In general it can be said that increase in elastane draft also increases the elastic recovery except 2.9 elastane draft. It is seen that denim fabrics have the highest elastic recovery at 2.9 elastane draft of 3.05, 1.15 and 0.57 dtex dual core-spun yarns.

#### **3.4. Wicking rate**

filaments from conventional to micro fineness contribute static tear force of denim fabrics except 0.57 dtex microfilament containing filament core-spun denim fabric. PET filament with 0.57 dtex filament fineness has the lowest breaking strength and so it can be said that filament properties affect the denim fabric properties as well. In addition, static tear force increases until 3.2 elastane draft ratio for all dual core-spun denim fabric types except 0.33 dtex filament containing dual core-spun denim fabric. Then, it is observed that after 3.2 draft value the increase in elastane draft effects static tear force negatively. Static tearing action leads to as the broken of the yarns individually or group. Hereby, increasing the elastane draft contributes tear force until 3.2 draft value because of the rising Co content. Furthermore, PET filament with fine and micro fineness contribute the tearing performance of the denim fabrics, because of the higher number of filament in the core of the dual core-spun yarns acts more resistance to break. This result can be explained with higher number of filament in the core of the dual

During usage of the denim should stretch freely in accordance with body movements especially at knee and should retain its original shape without any deformation after stretching. So that capability of extension and recovery of denim after repeated loadings is very important characteristics [38]. Higher the number of the loadings can contribute to life assessment in accordance with evaluating the fabric performance. Different from the test standard, 50 cycle loadings were carried out in order to evaluate elastic recovery of denim samples rather than 5 of cyclic loadings. Elongation after 50 cyclic loading and un-recovered elongation after 60 min recovery period were estimated according to Eqs. (1) and (2), respectively in accordance with

where: *E* = extension (mm) at maximum force on the 50th cycles, *L* = initial length (mm).

*Q* − *P*

where: *Q* = distance between applied reference marks (mm) after a specified recovery period,

*S* − *C*

**Figure 10** displays weft wise elastic recovery of denim fabrics after waiting 60 min recovery period. It can be said that both filament and elastane improve stretchability and recovery

From Eqs. (1) and (2) elastic recovery of fabric can be expressed as following Eq. (3).

*<sup>E</sup>* <sup>−</sup> *LL* <sup>∗</sup> <sup>100</sup> (1)

*<sup>P</sup>* ∗ 100 (2)

*<sup>S</sup>* ∗ 100 (3)

core-spun yarns providing more resistance to break.

BS EN 14704-1. Elongation, *S*, expressed as percentage:

Un-recovered elongation, *C*, expressed as percentage:

*P* = initial distance between applied reference marks (mm).

properties of the denim fabrics when compared with pure Co ones.

*S* = \_\_\_\_

*<sup>C</sup>* <sup>=</sup> \_\_\_\_

*R* = \_\_\_\_

**3.3. Elastic recovery**

32 Engineered Fabrics

The wicking rate measurements in mm/s are presented in **Figure 11**. Weft wise wicking rate obtained for pure Co denim is lower than vertical filament core-spun denims. Vertical wicking rate of the filament core-spun denim fabrics decreases from 3.05 to 0.33 dtex. Since filaments are in the core part of the yarn, capillary transfer of water may not be fully observed during the period of time. This situation can be observed at the rest of the denim fabrics with different draft ratio. On the other hand, in general, the effect of the elastane draft can be seen

**Figure 10.** Weft wise elastic recovery of denim fabrics.

**Figure 11.** Weft wise wicking rate of denim fabrics.

as decreasing wicking rate of the denim fabrics. Decreasing in elastane draft causes increase in Co and it is known that Co absorbs the water instead of transfer, as well. In addition, it is also observed that increase in the number of filaments causes a decreasing wicking rate when the average of the values for each filament fineness including all elastane draft is taken into consideration.

In analyzing of filament fineness effect, 3.05 and 0.57 dtex dual core-spun yarn denim fabrics including all elastane draft have the lower wetted area percentage with the average value of 19 and 20.8%, respectively. On the other hand, 1.15 and 0.33 dtex dual core-spun yarn denim fabrics including all elastane draft have higher wetted are percentage with the average of 26.2 and 28.2%, respectively. The highest wetted area was found as 0.33 dtex, it can be explained

Denim Fabrics Woven with Dual Core-Spun Yarns http://dx.doi.org/10.5772/intechopen.80286 35

To put forward the influence of filament fineness and elastane draft parameters on denim fabric breaking force, breaking elongation, tear force, elastic recovery, vertical wicking rate and water absorption rate statistically, multivariate analysis of variance (MANOVA) was achieved at 95% confidence interval (**Table 6**). Statistical results indicate that filament fineness parameter has significant effect on all variables. Elastane draft has also significant importance on all

Application of core-spun yarns in textile industry is in progress to improve physical and mechanical properties of fabrics, such as comfort, abrasion resistance, tenacity, durability, and functional properties. Stretch denim fabrics are mostly produced from core-spun yarns. Advanced stretching performance provides better fitting to body. Cotton is the most appreciable material as sheath component of the yarn which is responsible for comfort and esthetic properties. Denims' clothing and fitting to human body, comfortable and performance properties are essential for consumers. The most acceptable driving factors for denim market are consumer demand, rapid change of fashion and denim styles, highly preferred by young people and these factors are changing in very short period of time. When the overall consumption of denim in the world and market size are taken into consideration, value-added and high durable denims produced from functional yarns will response to the desired com-

Since the denim fabrics have high demand in textile market and it is increasing day by day, this study is conducted to evaluate the developments in denim fabric production and submit an innovative case study to improve the performance of denim fabric. In day fashion trends, denim fabrics are now not only used for the jeans production, they are also used in the production of shirt, t-shirts, skirts, bags and different textile product accessories. Depending on the usage area of denim fabrics, different performances and functions are required from them. Different ways can be performed to improve the performances of the textile products. Using different pattern designs, selecting proper raw material, using specially produced yarns or applying finishing chemicals are effective treatments. The finishing and washing processes are applied to add higher hand property, better touch feeling and attractive appearance. Evidence in literature demonstrates that usage of different characteristic fiber and yarn is effective method to increase mechanical performance of the denim fabrics. The incorporation

as higher number of the filaments enables more liquid transportation.

depended variables except water absorption rate (*p = 0.077*) at the *0.05* level.

**3.6. Statistical analysis**

**4. Conclusion**

fort and fit characteristics as well.

#### **3.5. Water absorption rate after dropping**

Water absorption rate as percentage of the wetted area detected by image processing method by using MATLAB is illustrated in **Figure 12**. Naturally, it is known that the absorption of cotton fibers is better when compared to synthetic fibers. Water transfer occurs in synthetic fibers through capillary forces. So, the rate of absorption in pure Co denim i.e. the area of dropped colored water is found smaller after 2 min. On the other hand, it is seen that filament core-spun denim fabrics have at least two times greater absorption area than that of pure Co fabric. It can be said that the presence of PET filament leads to water or moisture transportation instead of penetration. It can be observed that there is no increase or decrease tendency of absorption rate of dual core-spun denim fabrics in terms of elastane draft. This situation can be explained with having different liquid transportation of fabrics depending on the filament fineness. Whereas the elastane has taken almost the entire stretch of fabrics, the PET filament here carries capillary properties of fabrics with its high capillary transport capability in moisture management.

**Figure 12.** Water absorption rate of denim fabrics.


**Table 6.** Multivariate analysis of variance (MANOVA) test results for weft wise properties of denim fabrics.

In analyzing of filament fineness effect, 3.05 and 0.57 dtex dual core-spun yarn denim fabrics including all elastane draft have the lower wetted area percentage with the average value of 19 and 20.8%, respectively. On the other hand, 1.15 and 0.33 dtex dual core-spun yarn denim fabrics including all elastane draft have higher wetted are percentage with the average of 26.2 and 28.2%, respectively. The highest wetted area was found as 0.33 dtex, it can be explained as higher number of the filaments enables more liquid transportation.

#### **3.6. Statistical analysis**

as decreasing wicking rate of the denim fabrics. Decreasing in elastane draft causes increase in Co and it is known that Co absorbs the water instead of transfer, as well. In addition, it is also observed that increase in the number of filaments causes a decreasing wicking rate when the average of the values for each filament fineness including all elastane draft is taken into

Water absorption rate as percentage of the wetted area detected by image processing method by using MATLAB is illustrated in **Figure 12**. Naturally, it is known that the absorption of cotton fibers is better when compared to synthetic fibers. Water transfer occurs in synthetic fibers through capillary forces. So, the rate of absorption in pure Co denim i.e. the area of dropped colored water is found smaller after 2 min. On the other hand, it is seen that filament core-spun denim fabrics have at least two times greater absorption area than that of pure Co fabric. It can be said that the presence of PET filament leads to water or moisture transportation instead of penetration. It can be observed that there is no increase or decrease tendency of absorption rate of dual core-spun denim fabrics in terms of elastane draft. This situation can be explained with having different liquid transportation of fabrics depending on the filament fineness. Whereas the elastane has taken almost the entire stretch of fabrics, the PET filament here carries capillary properties of fabrics with its high capillary transport capability in moisture management.

consideration.

34 Engineered Fabrics

**3.5. Water absorption rate after dropping**

**Figure 12.** Water absorption rate of denim fabrics.

**Breaking force (N)**

\*The mean difference is significant at the *0.05* level.

**Breaking elongation (%)** **Static tear force (N)**

Filament fineness 0.000\* 0.003\* 0.000\* 0.000\* 0.000\* 0.000\* Elastane draft 0.000\* 0.000\* 0.000\* 0.000\* 0.000\* 0.077

**Table 6.** Multivariate analysis of variance (MANOVA) test results for weft wise properties of denim fabrics.

**Vertical wicking rate (%)**

**Elastic recovery (%)** **Water absorption rate (%)**

**Independent variables**

To put forward the influence of filament fineness and elastane draft parameters on denim fabric breaking force, breaking elongation, tear force, elastic recovery, vertical wicking rate and water absorption rate statistically, multivariate analysis of variance (MANOVA) was achieved at 95% confidence interval (**Table 6**). Statistical results indicate that filament fineness parameter has significant effect on all variables. Elastane draft has also significant importance on all depended variables except water absorption rate (*p = 0.077*) at the *0.05* level.
