**5. Materials, suitable for joining the textiles using heat**

#### **5.1. Fusible interlining**

The term "fusible interlining" is generally defined as a base fabric having a deposit of ther‐ moplastic adhesive resin, which can be bonded to another fabric by the application of heat and pressure. The purpose of fusible interlinings is to achieve better shape retention in the garment, particularly after laundering, increase strength and stability of the outer fabric, create a firm structure and improve the shape of the garment, add warmth, increase bulkiness, improve handling during sewing, improve the feel or crease resistance, as well as to give a better folded edge in the finished garment.

According to the structure, the support material of fusible interlining can be woven, knitted nonwoven. The thermoplastic adhesive is coating on the base fabric by the different kind of coating methods, **Figure 9** [4, 17]. The end form can be scatter powder, powder print, paste print dot, and 3P dot‐process [13].

**Figure 9.** The types of coated adhesive on base cloth or substrate [13].

For the paste print process, the adhesive polymer powder is mixed into an aqueous dispersion. This is applied with a rotation screen printing. The paste is forced through the preformation onto the interlining fabric. Afterward, the adhesive is dried, **Figure 9a** [13]. The 3P dot is a combination of the pate printing and powdering process, **Figure 9b** [13]. First, the paste dot is deposited onto the fabric, then the powder is scattered onto it. Afterward, the adhesive is dried and sintered. The underlying dot acts as a barrier in order to prevent the adhesive from penetrating into the interlining and direct it toward the outer fabric. In this way, the bond is optimized, difficult to fuse outer fabrics. The powder point process is a gravure printing process of adhesive onto the preheated interlining, **Figure 9c** [13]. In scatter powder process, the thermoplastic powder is drawn from a powder by a spiked roller. The adhesive is then heated with infra‐red heaters and bonded to the base material and flattened by pressing rollers, **Figure 9d** [13].

The fusible interlining has not only great influence on the hand value of a fused panel, but also on the aesthetic appearance, functionality, shape or model stability, as well as on the end use of the garment.

## **5.2. Welding tapes**

**Figure 7.** Hot air (a) and wedge (b) welding equipment [1].

224 Joining Technologies

**Figure 8.** Hot air welding machines. (a) PFAFF 8303i [15] and (b) Framis MX 212 [16].

**5. Materials, suitable for joining the textiles using heat**

The term "fusible interlining" is generally defined as a base fabric having a deposit of ther‐ moplastic adhesive resin, which can be bonded to another fabric by the application of heat and pressure. The purpose of fusible interlinings is to achieve better shape retention in the garment, particularly after laundering, increase strength and stability of the outer fabric, create a firm

**5.1. Fusible interlining**

The Pfaff Industrial is a leader in manufacturing of machine for programmed seam sealing. The last model 8303i offers an increase in productivity of up to 20% compared with other taping machines, **Figure 8a** [15]. Manufacturer of welding machines and welding tapes company Framis [17] offers various welding machines for seamless joining and welding. Their trade‐ mark NoSo®, **Figure 8b**, heat bonding machines ensures depended on machine model raw cut edge for elasticated hem, raw cut edge with two sided adhesion tape for overlapped seams, folded edges in a single operation, seam sealing taping, decorative taping on open or finished garments, join of two fabrics where an adhesive tape has to have been applied between them.

> Welding tape for textile purposes presents a textile material coated with an adhesive on one or two sides of a textile substrate. The adhesives can be supplied in a variety of forms, such as film, web, tape, multilayer, fabric backed and release film backed, and the width can be adjusted according to the application issues. They may also be preapplied to the fabric, i.e., substrate in the form of dots or nonwoven layer, or built into the structure of the fabric as a low melting point fiber among higher melting point material. The following adhesives are

used for manufacturing of the welding tape (two/three‐layered) according to used raw material of the substrate [1]:

Mainly, the functions of the welding tapes are to cover and reinforce seams, as well as they can have also some decorative functions. Those welding tapes are extremely versatile and are used in a wide range of applications. Some of the welded seams are shown in **Figure 10**.

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The selection of suitable materials for joining the textile materials using heat is mainly based on experiences of experts who use different nonuniform methods. The process of selection of

Before any fusing process, it is necessary to perform the testing of a fused panel in order to determine if the resulting fused panel would meet the desired properties both during the manufacturing process and later during the application. The mentioned selection methodol‐ ogy can be also transformed for selection of the welding tapes, because the same characteristics

To achieve the desired silhouette during the construction and planning of a garment, the kind and quality of both the shell fabric and the fusible interlining must be harmonized. The shell fabrics are chosen according to the fashion style of the garment, but the fusible interlinings are selected not only for the fashion style of the garment but also taking into account the type of

**5.3. Selection of materials for joining the textile materials using heat**

**Figure 11.** Systematic approach for selection of the fusible interlining.

of joins should be taken into account.

*5.3.1. Selection of the fusible interlinings*

the shell fabrics.

fusible interlinings was thoroughly studied by Japanese authors [9], **Figure 11**.


The textile substrates can be woven, knitted, nonwoven fabric, or synthetic films, i.e., 100% polyamide or 100% polyurethane. According to the number of layers, the welding tapes are divided as follows:



**Figure 10.** Welded seams manufactured by a welding tape coated on one side [16].

Mainly, the functions of the welding tapes are to cover and reinforce seams, as well as they can have also some decorative functions. Those welding tapes are extremely versatile and are used in a wide range of applications. Some of the welded seams are shown in **Figure 10**.

### **5.3. Selection of materials for joining the textile materials using heat**

used for manufacturing of the welding tape (two/three‐layered) according to used raw

**•** polyester fabrics—polyurethane, polyamide, polyolefin, and polyester‐based adhesive

**•** polyamide (nylon) fabrics—some polyurethane films, polyamide, and polyester films,

**•** cotton fabrics—some polyurethane, polyamide, polyester, polyolefin, and vinyl films,

**•** elastic fabrics (containing lycra) —polyurethane and polyamide films have been designed

The textile substrates can be woven, knitted, nonwoven fabric, or synthetic films, i.e., 100% polyamide or 100% polyurethane. According to the number of layers, the welding tapes are

**•** three‐layered (i.e., 1. layer‐synthetic film, 2. layer‐synthetic film, and 3. layer‐textile sub‐

**•** acetate fabrics—some polyamide, polyester, and polyolefin films,

**•** wool fabrics—some polyurethane, copolyester, and polyamide films,

**•** two‐layered (i.e., 1. layer‐synthetic film and 2. layer‐synthetic film), and

**Figure 10.** Welded seams manufactured by a welding tape coated on one side [16].

that retain their elastic properties after the bonding process,

**•** polyurethane foams—polyurethane and copolyester films,

**•** PVC foams—polyurethane, polyester, and vinyl films,

material of the substrate [1]:

**•** acrylic fabrics—polyamide films,

**•** aramid fabrics – polyurethane films,

**•** polyethylene foams—polyolefin films.

divided as follows:

strate).

**•** one‐layered (synthetic film),

films,

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The selection of suitable materials for joining the textile materials using heat is mainly based on experiences of experts who use different nonuniform methods. The process of selection of fusible interlinings was thoroughly studied by Japanese authors [9], **Figure 11**.

**Figure 11.** Systematic approach for selection of the fusible interlining.

Before any fusing process, it is necessary to perform the testing of a fused panel in order to determine if the resulting fused panel would meet the desired properties both during the manufacturing process and later during the application. The mentioned selection methodol‐ ogy can be also transformed for selection of the welding tapes, because the same characteristics of joins should be taken into account.

#### *5.3.1. Selection of the fusible interlinings*

To achieve the desired silhouette during the construction and planning of a garment, the kind and quality of both the shell fabric and the fusible interlining must be harmonized. The shell fabrics are chosen according to the fashion style of the garment, but the fusible interlinings are selected not only for the fashion style of the garment but also taking into account the type of the shell fabrics.

The quality of the fused panel can be determined on the basis of the bond strength, the visual appearance of the fused area, as well as the results of measurement of the mechanical and physical properties, such as tensile, bending and shear properties, formability and its dimen‐ sional stability under the process of fusing, and later after washing or chemical laundering [8]. Bond strength of the fused panel is determined by the force, required to separate the interlining and shell fabrics and is determinate by standard DIN 54310 [18]. The bond strength is the major parameter for quality estimation of the fused panel. The comparison of a bond strength of fused panel after fusing and chemical cleaning for six different fusible interlinings fused with the woolen fabric, suitable for upper garments, is shown in **Table 1**. Fusible interlinings differed regarding the raw material, weave, and type of the adhesive. Fabrics have had different surface fabric weight, weft and warp density, color, and weave.

The visual appearance of the garment is evaluated on the basis of visual appearance of the fused panel. The main influencing factors are breakthrough of the thermoplastic material through the surface of a shell fabric or interlining, changes in the surface structure of the shell

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The presented facts have confirmed the importance of a suitable selection of all parameters that affect the fusing process. In general, the selection of an appropriate interlining can be

**•** basic characteristics, which determine the properties of certain interlinings in the process of

**•** the mechanical properties of the fusible interlining with respect to the used shell fabric.

A system for automatic knowledge acquisition from a given set of examples presents an alternative way to build a knowledge base to determine the quality of a fused panel. The design of a knowledge base of an expert system is very challenging and responsible work because it

The studies have shown that machine learning from examples allows quick and systematic selection of fusible interlinings with regard to desired final mechanical properties of a fused panel [6]. For the operation of such a system, it is necessary to collect and systemize the data representing learning examples of which the rules are generated in the form of decision trees. The example of one of the constructed rules for predicting the formability of a fused panel

**Figure 12.** One constructed rule in a part of a regression tree for predicting the formability of a fused panel in a weft

*5.3.2. Example of selection of the fusible interlinings using machine learning*

must include the entire expert knowledge from the specific area [6, 19–22].

based on 300 examples is shown in a part of the regression tree, **Figure 12**.

fabric, and the moiré effect phenomena [6].

defined on the basis of adjusting to:

direction.

stabilization and the end use, and


**Table 1.** Comparison of bond strength of a fused panel after fusing and chemical cleaning.

It can be seen that the fusible interlining's structure influenced the bond strength after the fusing process and chemical cleaning. The bond strength is decreased after chemical cleaning irrespective of used fusible interlining. There may be several causes. During the chemical cleaning the garment is affected by different influences simultaneously or following one after another. The chemical cleaning process is combined with the following steps: cleaning clothes in the cleaning solution, followed by drying and ironing. The chemical solvent can affect the engorgement of fibers, thus the adhesion of fibers in the fabric is reduced to the thermoplastic adhesive of a fusible interlining. This results in decreasing of the bond strength [6]. The quality of the fused panel after dry cleaning is also reduced with the formation of blisters, longitudinal lines, and with the punching of the thermoplastic adhesive on the face side of a fabric [6]. The cause for occurrence of blistering can also be in the properties of the thermoplastic adhesive; they may not be resistant to the cleaning solution, or the fused parameters could be improperly selected, i.e., they could be too high or too low. The chemical cleaning machine operation can also reduce the bond strength of a fused panel because of the mechanical forces generated during the movement of the machine and thereby appeared friction among the treated garment.

The visual appearance of the garment is evaluated on the basis of visual appearance of the fused panel. The main influencing factors are breakthrough of the thermoplastic material through the surface of a shell fabric or interlining, changes in the surface structure of the shell fabric, and the moiré effect phenomena [6].

The presented facts have confirmed the importance of a suitable selection of all parameters that affect the fusing process. In general, the selection of an appropriate interlining can be defined on the basis of adjusting to:


#### *5.3.2. Example of selection of the fusible interlinings using machine learning*

The quality of the fused panel can be determined on the basis of the bond strength, the visual appearance of the fused area, as well as the results of measurement of the mechanical and physical properties, such as tensile, bending and shear properties, formability and its dimen‐ sional stability under the process of fusing, and later after washing or chemical laundering [8]. Bond strength of the fused panel is determined by the force, required to separate the interlining and shell fabrics and is determinate by standard DIN 54310 [18]. The bond strength is the major parameter for quality estimation of the fused panel. The comparison of a bond strength of fused panel after fusing and chemical cleaning for six different fusible interlinings fused with the woolen fabric, suitable for upper garments, is shown in **Table 1**. Fusible interlinings differed regarding the raw material, weave, and type of the adhesive. Fabrics have had

different surface fabric weight, weft and warp density, color, and weave.

**Bond strength/N/5 cm**

**Minimum value Maximum value Minimum value Maximum value**

It can be seen that the fusible interlining's structure influenced the bond strength after the fusing process and chemical cleaning. The bond strength is decreased after chemical cleaning irrespective of used fusible interlining. There may be several causes. During the chemical cleaning the garment is affected by different influences simultaneously or following one after another. The chemical cleaning process is combined with the following steps: cleaning clothes in the cleaning solution, followed by drying and ironing. The chemical solvent can affect the engorgement of fibers, thus the adhesion of fibers in the fabric is reduced to the thermoplastic adhesive of a fusible interlining. This results in decreasing of the bond strength [6]. The quality of the fused panel after dry cleaning is also reduced with the formation of blisters, longitudinal lines, and with the punching of the thermoplastic adhesive on the face side of a fabric [6]. The cause for occurrence of blistering can also be in the properties of the thermoplastic adhesive; they may not be resistant to the cleaning solution, or the fused parameters could be improperly selected, i.e., they could be too high or too low. The chemical cleaning machine operation can also reduce the bond strength of a fused panel because of the mechanical forces generated during the movement of the machine and thereby appeared friction among the treated

**After fusing process After chemical cleaning**

F‐M‐1 7.10 13.81 5.58 11.80 F‐M‐2 6.96 13.09 6.36 12.84 F‐M‐3 7.61 17.33 8.43 17.14 F‐M‐4 5.92 15.20 5.17 13.53 F‐M‐5 6.78 12.31 4.56 12.24 F‐M‐6 6.47 14.03 3.07 12.92

**Table 1.** Comparison of bond strength of a fused panel after fusing and chemical cleaning.

**Code of a fused panel**

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garment.

A system for automatic knowledge acquisition from a given set of examples presents an alternative way to build a knowledge base to determine the quality of a fused panel. The design of a knowledge base of an expert system is very challenging and responsible work because it must include the entire expert knowledge from the specific area [6, 19–22].

The studies have shown that machine learning from examples allows quick and systematic selection of fusible interlinings with regard to desired final mechanical properties of a fused panel [6]. For the operation of such a system, it is necessary to collect and systemize the data representing learning examples of which the rules are generated in the form of decision trees. The example of one of the constructed rules for predicting the formability of a fused panel based on 300 examples is shown in a part of the regression tree, **Figure 12**.

**Figure 12.** One constructed rule in a part of a regression tree for predicting the formability of a fused panel in a weft direction.

In the same way, it is possible to predict also mechanical and physical properties as well as bond strength of fused panel. The comparison between predicted and measured values of bond strength can be elaborated in the form of a linear coefficient of correlation. In the study [22], a very high correlation, 0.87, between the measured and predicted values has been found. Linear correlation coefficient is shown in **Figure 13**. Unfortunately, in the market there are no commercial software programs for selection of the fusible interlinings.

First of all, the joint between the welding tape and fabric should be adjusted from the bonding strength point of view when hot air welding parameters are planned. The results have shown that samples welded at lower temperatures and high speeds have lower bond strengths. Hence, the bonding strengths were higher when the samples were exposed to slower welding processes irrespective of applied welding temperature. The bonding strengths of the welded transmission lines, which have the value of the bond strength within the range of 12.75–17.55 N/5 cm, represent the desired bond strength for applicable purposes, such as waterproof

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Hot air welding is mainly used in the healthcare and personal protective product sectors for making seams in nonwoven and coated nonwoven fabrics, also in welding of neoprene wet or dry suits. Hot wedge welding is used for joining heavy fabrics and films in outdoor applications, such as lining of swimming pools, reservoirs, and landfill sites [7]. On the other hand, fusing is mainly used for improving the shape and visual appearance of produced

The final form of a produced garment depends on the quality of the build‐in material and its construction requirements. The fused panel properties can be estimated subjectively or objectively after the garment is finished. Mainly, they are evaluated on the basis of mechanical properties, bond strength, and drapability. The drapability of the fabric is one of the most significant properties, which characterize the shape of a produced garment and its adaptation

The drape parameters depend on construction parameters of a fabric, row materials, and steps of finishing processes of fabric manufacturing, as well as on fusing technology used for production of a garment. The interlining can change the fabric properties, such as stiffness and extension properties, hand, visual appearance of incorporated pattern of a garment regarding

It is a ratio of a projected pleating fold area formed by a piece of fabric after draping under its own weight to the original area of this piece of fabric without draping. The higher the fabric drape coefficient, the lower the fabric drapability [25]. It is the percentage of the ring, between radius *R*1 of the fabric and radius *R*2 of the disc holding the fabric, which is covered by the

> 2 1 2 2 2 1 *<sup>p</sup> S R*


*R R* p

 p

p

projected shadow (**Figure 14**), and it can be determined by Cusick [25]:

*CD*

protection or for appropriate joining of different textile components together [23].

**6. Application of materials joined using heat**

garments [24].

to the human body.

**6.1. Drape properties of fused panels**

to the desired design requirements.

**Figure 13.** Correlation between the measured and predicted values of bond strength.

#### *5.3.3. Example of selection of welding tapes*

The selection of a welding tape is based on the polymer or natural fiber type, type of textile fabric, tightness of the weave or knit, the weight of the substrate, the mechanical property requirements of the joint, and the environmental conditions of use. The welding parameters, such as the temperature of the hot air, velocity, pressure, and pressure of hot air should be balanced according to selected fabric, welding tape, and machine applied. The suitable selection of a welding tape is important in defining the quality, performance, feel, stretch, and longevity of the joint made. The selection procedure can be the same as for the selection of the fusible interlining [23]. The bond strength is valid for the prior parameter when welding tapes are selected. The influence of welding parameters on bond strength of welded samples is presented in **Table 2**.


**Table 2.** Bonding strength of welded samples.

First of all, the joint between the welding tape and fabric should be adjusted from the bonding strength point of view when hot air welding parameters are planned. The results have shown that samples welded at lower temperatures and high speeds have lower bond strengths. Hence, the bonding strengths were higher when the samples were exposed to slower welding processes irrespective of applied welding temperature. The bonding strengths of the welded transmission lines, which have the value of the bond strength within the range of 12.75–17.55 N/5 cm, represent the desired bond strength for applicable purposes, such as waterproof protection or for appropriate joining of different textile components together [23].
