Non-Woven Fabrics Technology

**85**

**Chapter 5**

**Abstract**

reduced pore size.

porosity, fogging

**1. Introduction**

Characteristics of Eco-friendly

for Automotive Application

*Seung Jin Kim and Hyun Ah Kim*

Kenaf Fiber-Imbedded Nonwoven

This study examined the physical properties of kenaf fiber-imbedded nonwoven for automotive pillar trim according to the blend ratio of the fibers and needle-punching process conditions. Kenaf-imbedded nonwoven specimens mixed with polypropylene (PP) and low-melt PET (LM PET) fibers were prepared via needle-punching, and their physical properties such as air permeability, water absorption, sound absorption coefficient, and porosity were investigated according to the various processing conditions. The kenaf-imbedded nonwoven treated with high needle depth in the needle-punching process and/or mixed with a large amount of LM PET exhibited the highest breaking and tearing strengths, due to the high weight of the nonwoven specimens. A high blend percentage of LM PET fibers reduced the pore size, which resulted in low air permeability and water absorption. The sound absorption coefficient of the kenaf-imbedded nonwoven specimens was highly dependent on its weight and thickness. Regarding the lamination treatment, the laminated nonwoven exhibited higher breaking and tearing strengths, thermal conductivity, and sound absorption coefficient than the non-treated one. In addition, the HDPE powder-treated nonwoven exhibited lower breaking and tearing strengths, air permeability, water absorption, and sound absorption, due to the

**Keywords:** kenaf, needle-punching, low-melt PET, sound absorption coefficient

The scientific name of kenaf is *Hibiscus cannabinus* L. The principal ingredients of kenaf fiber are cellulose, lignin, and pectin, and the hemicellulose distribution ranges between 10 and 22% according to the type of kenaf fiber. Research on the application to fashion textile materials with soft tactile hand by retting treatment of kenaf stem has been conducted by Ramaswamy et al. [1], Tao et al. [2], and Lee et al. [3, 4]. In particular, many studies have examined the spinning and fabric manufacturing technology using mixed fibers with cotton and kenaf, including Bel-Berger et al. [5], Weiying et al. [6], and Zhang [7]. Advanced composite materials mixed with kenaf and natural fibers with light weight, VOC-free, and good abrasion resistance are needed nowadays and have been studied for eco-friendly automotive materials [8–10]. In addition, the use of kenaf fiber in nonwoven

#### **Chapter 5**

## Characteristics of Eco-friendly Kenaf Fiber-Imbedded Nonwoven for Automotive Application

*Seung Jin Kim and Hyun Ah Kim*

#### **Abstract**

This study examined the physical properties of kenaf fiber-imbedded nonwoven for automotive pillar trim according to the blend ratio of the fibers and needle-punching process conditions. Kenaf-imbedded nonwoven specimens mixed with polypropylene (PP) and low-melt PET (LM PET) fibers were prepared via needle-punching, and their physical properties such as air permeability, water absorption, sound absorption coefficient, and porosity were investigated according to the various processing conditions. The kenaf-imbedded nonwoven treated with high needle depth in the needle-punching process and/or mixed with a large amount of LM PET exhibited the highest breaking and tearing strengths, due to the high weight of the nonwoven specimens. A high blend percentage of LM PET fibers reduced the pore size, which resulted in low air permeability and water absorption. The sound absorption coefficient of the kenaf-imbedded nonwoven specimens was highly dependent on its weight and thickness. Regarding the lamination treatment, the laminated nonwoven exhibited higher breaking and tearing strengths, thermal conductivity, and sound absorption coefficient than the non-treated one. In addition, the HDPE powder-treated nonwoven exhibited lower breaking and tearing strengths, air permeability, water absorption, and sound absorption, due to the reduced pore size.

**Keywords:** kenaf, needle-punching, low-melt PET, sound absorption coefficient porosity, fogging

#### **1. Introduction**

The scientific name of kenaf is *Hibiscus cannabinus* L. The principal ingredients of kenaf fiber are cellulose, lignin, and pectin, and the hemicellulose distribution ranges between 10 and 22% according to the type of kenaf fiber. Research on the application to fashion textile materials with soft tactile hand by retting treatment of kenaf stem has been conducted by Ramaswamy et al. [1], Tao et al. [2], and Lee et al. [3, 4]. In particular, many studies have examined the spinning and fabric manufacturing technology using mixed fibers with cotton and kenaf, including Bel-Berger et al. [5], Weiying et al. [6], and Zhang [7]. Advanced composite materials mixed with kenaf and natural fibers with light weight, VOC-free, and good abrasion resistance are needed nowadays and have been studied for eco-friendly automotive materials [8–10]. In addition, the use of kenaf fiber in nonwoven

was investigated by Moreau et al. [11], Yang et al. [12], and Tao et al. [13, 14]. Nonwoven has been used in the various industries because of its advantages of fast processing and competitive price. Recently, nonwoven has become one of the most common textile products in the automotive industry with sound absorption properties. The nonwoven fabrics used in the automotive industry require high functional quality and reliability. Many studies have examined the sound absorption property, including physical properties such as air permeability and wicking, of nonwovens. The studies carried out using natural jute [15] and coconut coir [16] fibers yielded good sound absorption properties. Kenaf, jute, and cotton fiber-imbedded nonwovens with PET and polypropylene (PP) fibers were used as industrial automotive padding materials and have significantly improved the sound absorption properties [17]. Nick et al. [18] investigated the acoustic behavior using three different composite materials: (1) cotton, bicomponent PET, and PP fibers; (2) flax, hemp, and PP fibers; and (3) lyocell, bicomponent PET, and PP fibers. The third composite material with lyocell fibers of 0.9 dtex exhibited the best sound absorption property. Lou et al. [19] studied the sound absorption property of nonwoven composed of low-melt PET (LM PET) and recycled PET particles mixed with PP fibers. The thick and low-density nonwoven specimens exhibited high sound absorption coefficients at low- and mid-frequency sound ranges. Lee et al. [20] examined the relationship between the acoustic absorption values of the recycled polyester nonwovens and the nonwoven processing conditions, including fiber and web properties. Byun et al. [21] investigated the sound absorption property of the PET nonwoven for automotive application according to the variation of the fiber fineness, density, and thickness of the three-layer nonwoven by substituting glass wool in order to improve the environmental and recycled capability. Kücük and Korkmaz [22] examined the effects of the physical parameters on the sound absorption properties of natural fiber-mixed nonwoven fabrics. They concluded that an increased thickness and decreased air permeability resulted in an increase of sound absorption properties. In addition, an increased amount of fiber per unit area resulted in an increase in sound absorption. On the other hand, Dubrovski and Brezocnik [23] studied the effects of the content of viscose and PET fibers and the porosity of the nonwoven structure on the vertical wicking rate of nonwovens. The results showed that higher-volume porosity gives higher vertical wicking rate. Soukupova et al. [24] studied the effect of the blend ratio of viscose and PET fibers on the wicking of the nonwoven and found that the capillary rise was higher for nonwoven fabrics containing more viscose fibers. Dubrovski and Brezocnik [25] predicted the model for the vertical wicking rate using the fiber density, fiber fineness, and nonwoven fabric density. Das et al. [26] and Tascan and Vaughn [27] examined the influence of fiber cross-sectional shape on the air permeability of nonwoven. Das et al. [26] found that the air permeability decreased with a higher proportion of noncircular fibers in the nonwoven fabrics, which was similar to Tascan and Vaughn's results [27].

In previous studies, LM PET and PP fibers as nonwoven materials were mixed with natural fibers such as cotton, lyocell, flax, jute, and coconut coir to enhance their physical properties such as the wicking rate, air permeability, and sound absorption property for automotive-acoustic materials. However, no detailed study has yet examined the physical properties of the kenaf fiber-imbedded nonwoven. Therefore, in this study, kenaf fiber-imbedded nonwoven specimens were produced with different processing conditions such as number of carding treatments, web layers, needle depth, and content ratio of LM PET, and their physical properties such as air permeability, water absorption, and sound absorption coefficient were measured in order to optimize the processing conditions for automotive pillar trim. Furthermore, the correlation between the breaking and tearing strengths and the

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**Table 1.**

*Physical properties of staple fibers used.*

*Characteristics of Eco-friendly Kenaf Fiber-Imbedded Nonwoven for Automotive Application*

structural factors of the nonwoven were investigated according to the processing conditions. In addition, the effect of different processing conditions on the fogging

Kenaf, PP, and LM PET were used as raw materials of the nonwoven. **Table 1** presents the physical properties of the kenaf, PP, and LM PET staple fibers used. Ten kinds of kenaf-imbedded nonwoven specimen as a first batch of specimen were

**Figure 2** shows an image of the nonwoven machinery used. Three types of staple fiber supplied from material supply equipment were mixed and blended in the mixing tank shown in **Figure 1**. Specimen 1 in **Table 1** was mixed and blended by single opener in the mixing tank, and specimens 2–10 were prepared by multi-opener.

**Figure 1** shows the needle-punching nonwoven process to prepare the specimens.

As shown in **Table 2**, the basic blend ratio of kenaf, PP, and LM PET staple fibers was 40, 40, and 20%, respectively (specimens 1–9). The blend ratio of specimen 10 was changed to 30, 30, and 40%. The mixed and blended fibers were delivered to the first and second carding processes. The basic carding treatment was conducted twice, but specimen 4 underwent only one treatment. Lap forming was performed after the carding process. The layering of the carding lap was changed from two to four layers, as shown in **Table 2**. The needle-punching process was followed by the second web-forming process, as shown in **Figure 1**. The basic needle depth was 16 mm, but specimens 7 and 8 had a needle depth of 18.6 and 14.4 mm, respectively. The specimens underwent thermo-compression bonding after the needlepunching process, as shown in **Figure 1**. Polyethylene (PE) powder was added after the thermo-bonding process to enhance coherence between the fabric and PP foam when automotive pillar trim was fabricated, as shown in **Figure 3**. **Figure 3** shows the pillar trim in automotive interior. Kenaf-imbedded nonwoven is located between PP foam and fabric, which is placed on the inside of automotive pillar trim.

made with different processing conditions, as shown in **Table 2**.

Fabric is usually made by polyester (cation dyeable polyester).

among hot melt film, fabric, and kenaf-imbedded nonwoven.

**Physical properties Kenaf Low-melting PET** 

Hot melt film was inserted between the fabric and the kenaf-imbedded nonwoven to enhance the adhesive force between them. In addition, the reason why low-melting (LM) PET is mixed to make nonwoven is to enhance the adhesive force

Fiber length (mm) 64.8 51.8 ± 5.0 64 Linear density (d) 8 4.53 ± 0.41 8 ± 0.5 Maker/origin Bangladesh Toray Chemical Han Kook Fiber

Breaking strength (gf/d) 4 3.52 ± 0.42 4 ± 0.5 Breaking strain (%) 200 44.0 ± 8.7 200 ± 20 Moisture regain (%) 11.8 — 0.1

**(LM PET)**

**Polypropylene (PP)**

Co. Ltd

*DOI: http://dx.doi.org/10.5772/intechopen.85367*

value of the nonwoven was investigated.

**2. Experimental**

**2.1 Specimen preparation**

structural factors of the nonwoven were investigated according to the processing conditions. In addition, the effect of different processing conditions on the fogging value of the nonwoven was investigated.

#### **2. Experimental**

*Generation, Development and Modifications of Natural Fibers*

which was similar to Tascan and Vaughn's results [27].

In previous studies, LM PET and PP fibers as nonwoven materials were mixed with natural fibers such as cotton, lyocell, flax, jute, and coconut coir to enhance their physical properties such as the wicking rate, air permeability, and sound absorption property for automotive-acoustic materials. However, no detailed study has yet examined the physical properties of the kenaf fiber-imbedded nonwoven. Therefore, in this study, kenaf fiber-imbedded nonwoven specimens were produced with different processing conditions such as number of carding treatments, web layers, needle depth, and content ratio of LM PET, and their physical properties such as air permeability, water absorption, and sound absorption coefficient were measured in order to optimize the processing conditions for automotive pillar trim. Furthermore, the correlation between the breaking and tearing strengths and the

was investigated by Moreau et al. [11], Yang et al. [12], and Tao et al. [13, 14]. Nonwoven has been used in the various industries because of its advantages of fast processing and competitive price. Recently, nonwoven has become one of the most common textile products in the automotive industry with sound absorption properties. The nonwoven fabrics used in the automotive industry require high functional quality and reliability. Many studies have examined the sound absorption property, including physical properties such as air permeability and wicking, of nonwovens. The studies carried out using natural jute [15] and coconut coir [16] fibers yielded good sound absorption properties. Kenaf, jute, and cotton fiber-imbedded nonwovens with PET and polypropylene (PP) fibers were used as industrial automotive padding materials and have significantly improved the sound absorption properties [17]. Nick et al. [18] investigated the acoustic behavior using three different composite materials: (1) cotton, bicomponent PET, and PP fibers; (2) flax, hemp, and PP fibers; and (3) lyocell, bicomponent PET, and PP fibers. The third composite material with lyocell fibers of 0.9 dtex exhibited the best sound absorption property. Lou et al. [19] studied the sound absorption property of nonwoven composed of low-melt PET (LM PET) and recycled PET particles mixed with PP fibers. The thick and low-density nonwoven specimens exhibited high sound absorption coefficients at low- and mid-frequency sound ranges. Lee et al. [20] examined the relationship between the acoustic absorption values of the recycled polyester nonwovens and the nonwoven processing conditions, including fiber and web properties. Byun et al. [21] investigated the sound absorption property of the PET nonwoven for automotive application according to the variation of the fiber fineness, density, and thickness of the three-layer nonwoven by substituting glass wool in order to improve the environmental and recycled capability. Kücük and Korkmaz [22] examined the effects of the physical parameters on the sound absorption properties of natural fiber-mixed nonwoven fabrics. They concluded that an increased thickness and decreased air permeability resulted in an increase of sound absorption properties. In addition, an increased amount of fiber per unit area resulted in an increase in sound absorption. On the other hand, Dubrovski and Brezocnik [23] studied the effects of the content of viscose and PET fibers and the porosity of the nonwoven structure on the vertical wicking rate of nonwovens. The results showed that higher-volume porosity gives higher vertical wicking rate. Soukupova et al. [24] studied the effect of the blend ratio of viscose and PET fibers on the wicking of the nonwoven and found that the capillary rise was higher for nonwoven fabrics containing more viscose fibers. Dubrovski and Brezocnik [25] predicted the model for the vertical wicking rate using the fiber density, fiber fineness, and nonwoven fabric density. Das et al. [26] and Tascan and Vaughn [27] examined the influence of fiber cross-sectional shape on the air permeability of nonwoven. Das et al. [26] found that the air permeability decreased with a higher proportion of noncircular fibers in the nonwoven fabrics,

**86**

#### **2.1 Specimen preparation**

Kenaf, PP, and LM PET were used as raw materials of the nonwoven. **Table 1** presents the physical properties of the kenaf, PP, and LM PET staple fibers used. Ten kinds of kenaf-imbedded nonwoven specimen as a first batch of specimen were made with different processing conditions, as shown in **Table 2**.

**Figure 1** shows the needle-punching nonwoven process to prepare the specimens. **Figure 2** shows an image of the nonwoven machinery used. Three types of staple fiber supplied from material supply equipment were mixed and blended in the mixing tank shown in **Figure 1**. Specimen 1 in **Table 1** was mixed and blended by single opener in the mixing tank, and specimens 2–10 were prepared by multi-opener.

As shown in **Table 2**, the basic blend ratio of kenaf, PP, and LM PET staple fibers was 40, 40, and 20%, respectively (specimens 1–9). The blend ratio of specimen 10 was changed to 30, 30, and 40%. The mixed and blended fibers were delivered to the first and second carding processes. The basic carding treatment was conducted twice, but specimen 4 underwent only one treatment. Lap forming was performed after the carding process. The layering of the carding lap was changed from two to four layers, as shown in **Table 2**. The needle-punching process was followed by the second web-forming process, as shown in **Figure 1**. The basic needle depth was 16 mm, but specimens 7 and 8 had a needle depth of 18.6 and 14.4 mm, respectively. The specimens underwent thermo-compression bonding after the needlepunching process, as shown in **Figure 1**. Polyethylene (PE) powder was added after the thermo-bonding process to enhance coherence between the fabric and PP foam when automotive pillar trim was fabricated, as shown in **Figure 3**. **Figure 3** shows the pillar trim in automotive interior. Kenaf-imbedded nonwoven is located between PP foam and fabric, which is placed on the inside of automotive pillar trim. Fabric is usually made by polyester (cation dyeable polyester).

Hot melt film was inserted between the fabric and the kenaf-imbedded nonwoven to enhance the adhesive force between them. In addition, the reason why low-melting (LM) PET is mixed to make nonwoven is to enhance the adhesive force among hot melt film, fabric, and kenaf-imbedded nonwoven.


#### **Table 1.**

*Physical properties of staple fibers used.*


#### **Table 2.**

*Processing conditions for ten kinds of kenaf-imbedded specimen.*

Therefore, to examine the effect of the polyurethane (PU)-laminating film treatment on the thermal conductivity, water absorption, and sound absorption properties of the kenaf-imbedded nonwoven, a second batch of specimens was prepared by the same procedure as that for the first batch. **Table 3** presents the eight types of nonwoven specimen as a second batch of specimens. Two types of specimen were prepared as nonlaminated (1–4) and laminated (5–8) by PU film. The blend ratio of kenaf, PP, and LM PET staple fibers was 40, 40, and 20% as a fixed blend ratio. The carding treatment was conducted twice, and the number of layers of the carding lap was fixed at three. The needle depth was fixed at 16 mm. In the thermo-compression bonding process, the surface temperature of the bonding roller was set at 170°C, and its velocity was fixed at 7.2 m/min. Specimens 1 and 3 were treated with powder after the thermo-compression bonding process and have different weight. Specimens 2 and 4 were non-treated and also have different weight. Specimens 5–8 were laminated by PU film after the needle-punching nonwoven process. The temperature of the laminating roller was 129°C, and the

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**Figure 3.**

*Schematic diagram of pillar trim.*

*Characteristics of Eco-friendly Kenaf Fiber-Imbedded Nonwoven for Automotive Application*

doting temperature on the melting apparatus was set at 126°C and the feed speed of the laminating roller at 3.7 m/min. After laminating by PU film, aging was carried

The breaking strength and strain of the nonwoven specimens were measured using Testometric apparatus (Model Micro 350, England) according to KSK ISO 9073- 3: 2009. A specimen of width 50 mm and length 200 mm was prepared and elongated at a speed of 100 mm/min. The tearing strength of the nonwoven specimens was measured using Testometric apparatus (Model Micro 350, England) according to KSK ISO 9073-4: 2010. A specimen of width 75 and length 150 mm was prepared. In addition, the breaking strength, strain, and initial modulus of the nonwoven specimens prepared at machine direction (MD) intervals of 30 degrees were measured. The preparation of the specimens is shown in **Figure 4**. Furthermore, the orientation factor of fibers in the nonwoven specimens was calculated as the measured inclined angle (θ) of the 500 fibers in the nonwoven fabric as shown in **Figure 5**, and the distribution of the measured angles was analyzed in relation to the measured tensile property.

The thickness of the ten (first batch specimen) and eight (second batch specimen)

was measured, and 30

different nonwoven specimens was measured using the FAST-1 system. **Figure 6** shows an image and schematic diagram of the compression meter by FAST-1 system

assessments of each specimen were carried out for calculating the mean thickness.

[28]. The thickness (mm) at a compression force of 2 gf/cm2

*DOI: http://dx.doi.org/10.5772/intechopen.85367*

out at 60% of RH in the aging room for 24 hours.

**2.2 Measurement of physical properties**

*2.2.1 Tensile and tearing strengths*

*Image of the nonwoven machinery.*

*2.2.2 Thickness*

**Figure 2.**

**Figure 1.** *Needle-punching nonwoven process.*

*Characteristics of Eco-friendly Kenaf Fiber-Imbedded Nonwoven for Automotive Application DOI: http://dx.doi.org/10.5772/intechopen.85367*

*Generation, Development and Modifications of Natural Fibers*

*Processing conditions for ten kinds of kenaf-imbedded specimen.*

**No. of carding treatment** **Layer of web**

 40:40:20 3 Layers 3 Layers 16 mm O X 40:40:20 3 Layers 3 Layers 16 mm O O 40:40:20 4 Layers 4 Layers 16 mm O O 40:40:20 2 Layers 2 Layers 16 mm O O 40:40:20 3 Layers 3 Layers 18.6 mm O O 40:40:20 3 Layers 3 Layers 14.4 mm O O 40:40:20 3 Layers 3 Layers 16 mm X O 30:30:40 3 Layers 3 Layers 16 mm O O

**Needle depth**

40:40:20 3 Layers 3 Layers 16 mm O O

40:40:20 3 Layers 3 Layers 16 mm O O

**Thermal compression bonding**

**Powder treatment**

**No. Blend ratio** 

1 Single opener

2 Multiopener

**Table 2.**

**(kenaf:PP:LM PET)**

Therefore, to examine the effect of the polyurethane (PU)-laminating film treatment on the thermal conductivity, water absorption, and sound absorption properties of the kenaf-imbedded nonwoven, a second batch of specimens was prepared by the same procedure as that for the first batch. **Table 3** presents the eight types of nonwoven specimen as a second batch of specimens. Two types of specimen were prepared as nonlaminated (1–4) and laminated (5–8) by PU film. The blend ratio of kenaf, PP, and LM PET staple fibers was 40, 40, and 20% as a fixed blend ratio. The carding treatment was conducted twice, and the number of layers of the carding lap was fixed at three. The needle depth was fixed at 16 mm. In the thermo-compression bonding process, the surface temperature of the bonding roller was set at 170°C, and its velocity was fixed at 7.2 m/min. Specimens 1 and 3 were treated with powder after the thermo-compression bonding process and have different weight. Specimens 2 and 4 were non-treated and also have different weight. Specimens 5–8 were laminated by PU film after the needle-punching nonwoven process. The temperature of the laminating roller was 129°C, and the

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**Figure 1.**

*Needle-punching nonwoven process.*


**Figure 2.** *Image of the nonwoven machinery.*

doting temperature on the melting apparatus was set at 126°C and the feed speed of the laminating roller at 3.7 m/min. After laminating by PU film, aging was carried out at 60% of RH in the aging room for 24 hours.

#### **2.2 Measurement of physical properties**

#### *2.2.1 Tensile and tearing strengths*

The breaking strength and strain of the nonwoven specimens were measured using Testometric apparatus (Model Micro 350, England) according to KSK ISO 9073- 3: 2009. A specimen of width 50 mm and length 200 mm was prepared and elongated at a speed of 100 mm/min. The tearing strength of the nonwoven specimens was measured using Testometric apparatus (Model Micro 350, England) according to KSK ISO 9073-4: 2010. A specimen of width 75 and length 150 mm was prepared. In addition, the breaking strength, strain, and initial modulus of the nonwoven specimens prepared at machine direction (MD) intervals of 30 degrees were measured. The preparation of the specimens is shown in **Figure 4**. Furthermore, the orientation factor of fibers in the nonwoven specimens was calculated as the measured inclined angle (θ) of the 500 fibers in the nonwoven fabric as shown in **Figure 5**, and the distribution of the measured angles was analyzed in relation to the measured tensile property.

#### *2.2.2 Thickness*

The thickness of the ten (first batch specimen) and eight (second batch specimen) different nonwoven specimens was measured using the FAST-1 system. **Figure 6** shows an image and schematic diagram of the compression meter by FAST-1 system [28]. The thickness (mm) at a compression force of 2 gf/cm2 was measured, and 30 assessments of each specimen were carried out for calculating the mean thickness.

**Figure 3.** *Schematic diagram of pillar trim.*

