**4.4. Non-woven textiles as wallcoverings**

and emergency use, though high-quality needle-punched blankets are also produced from

The comfort, related with upholstery textiles, is generally associated with their touch [31,32]. In fact, the touch of the textiles is one of the factors for physical and neurophysiological comfort of the individual. However, the comfort of furniture, covered with fabrics, is determined by the thermophysiological comfort of the person. The thermophysiological comfort, in turn, depends on the behavior of the textile barrier between the body and the piece of furniture [33].

Non-woven textiles are applied in 80–90% of foambacked furniture systems and mattresses [34]. They are the outermost layer of the system (being the upholstery layer) or are used to provide support for the upholstery fabric. Currently, there is a trend of replacing the traditional woven covers of mattresses, made of cotton yarns, with filament non-wovens made of

**•** Bonded polyester non-wovens as the outermost layer of furniture systems, which are not

**•** Laminated or quilted non-wovens as the outermost layer of foambacked upholstery with

Inside furniture systems, non-wovens are used for support, insulation, and comfort. Needlepunched waddings and paddings, made from natural and chemical fiber that are recycled from textile production waste, or virgin fiber from acrylic, polypropylene, and polyethylene terephthalate are among the most commonly used [35]. The non-wovens replace the polyur‐ ethane foams in furniture systems and mattresses. These are products, based on stitch-bonding technologies, which provide thermal insulation and reduce noise and vibration during operation of furniture and mattresses. Composite non-woven textiles, produced by a web from bi-component fibers, are also in use. They have the same quality as foam of the same thickness [34], but demonstrate higher air permeability, which is important for ensuring both the

There is no risk for the Indoor Air Quality (IAQ) in terms of gas emissions from the upholstery textiles [36]. The upholstery surface, however, creates the same problems of accumulation of dust and particulate matter as the floor coverings. Therefore, furniture systems can be a source of VOCs, MVOCs, etc. due to accumulation of dust and allergenic particles from other sources

A solution of that problem is the use of synthetic leather as outermost layer of furniture pieces. Non-wovens are successful substitute for genuine leather. Different materials and technologies are applied for the production of synthetic leather. At the same time, synthetic leathers are an excellent substitute for both woven and knitted upholstery fabrics, which positively influences

**•** Thermobonded non-wovens as the outermost layer of foambacked upholsters

natural and synthetic fibers [30].

196 Non-woven Fabrics

polyester and polypropylene.

subjected to high loads

high dimensional stability

Different types of non-woven coverings are in use [34]:

thermophysiological comfort and the retention of MVOCs.

of harmful substances in the indoor environment.

**4.3. Non-woven textiles in furniture**

Non-woven textiles are used more as commercial wallcoverings, applied in the interiors of public buildings (hotels, offices, hospitals). They must meet a series of requirements for flammability, abrasion resistance, washability and stain resistance, tear strength, etc.

The application of non-woven textiles for wallcoverings in the indoor is developing in two main directions: backing for wallcoverings and wallcoverings.

Non-wovens are used in fabric-backed vinyl wallcoverings, where a non-woven substrate is laminated to form a decorative surface of solid vinyl. Light or medium weight wallcoverings are produced with a non-woven backing. Traditional wallcovering substrates are produced with a non-woven backing: needle-punched or stitch-bonded layers [34].

Non-woven wallcoverings influence the IAQ as they can accumulate dust and are used in big areas in the indoor environment. Certainly, their effect on accumulation of dust and particles, released from other sources in the indoor environment is much lower than in the case of carpets and upholstery. Flocked wallcoverings, which have velvet appearance or 3D effects, require special attention. Being overlaid with very fine fibers of cotton, silk, or man-made fibers, the flocked wallcoverings must be subjected to frequent cleaning.

Non-wovens are applied for the production of textile wallcoverings with a variety of designs and textures. Products from synthetic/polyolefin fibers are additionally treated for higher abrasion and stain resistance. Polyolefin and polyester fibers are also applied for the produc‐ tion of acoustic wallcoverings. They have different levels of sound absorption, thus influencing the Indoor Sound Quality (ISQ).

## **4.5. Non-woven textiles as filters**

Non-woven textiles are used as filters in Heating, Ventilation, and Air-Conditioning (HVAC) systems in buildings. HVAC systems provide clean air for the inhabitants in public and residential built environment, including buildings where natural ventilation is not possible (i.e., due to closed glass facades). They also provide clean air for sensitive work places, which require zero dust and microbial emissions: operating rooms in hospitals, pharmaceutical production lines, production of electronic components and devices, research laboratories, etc.

Six types of non-woven filters used in residential buildings have been identified [37]. Five of them contain non-woven media: fiberglass filters, pleated filters with non-woven mats, reusable filters, electret filters, and deep pleated filters. All require regular change or cleaning: from one month in periods of normal use (for fiberglass filters) to once a year (for deep pleated filters).

Non-wovens are also used in air purifiers: portable units in the indoor environment, aimed to remove particles and odors and provide clean air for the occupants. Pleated and electret filters are used, like Technostat ® needle-punch felt media [38]. Glass microfiber HEPA filters, filter media of blends between synthetic and glass fibers, as well as composites with non-woven media are also in use. Non-woven felts from a mixture of natural and synthetic fibers are applied for a backing support [38].

In their role of filter media non-woven materials can influence the Indoor Air Quality (IAQ) and indoor odor quality (IOQ). HVAC systems and air purifiers increase the quality of the indoor environment when working properly and maintained correctly. Noncompliance with the requirements for cleaning or replacement of the particular filter media can lead to change of the indoor environmental quality for the worse. The main reasons are either the incapacity of the filters to retain dust and particles, or the growth of airborne microbial contaminants, which are spread from the filter media to the air of the enclosure, leading to increment of VOCs, MVOCs, and other pollutants of the indoor environment.

## **4.6. Non-woven textiles in cars**

The use of non-woven textiles in the sector of transportation is growing and the car industry is leading this trend. A number of applications of non-wovens in car construction are described in details in [39,40]: lining of doors boot and hoodcase, seat construction (including upholstery cover), filters, engine housing, etc. The requirements for the types of the non-wovens used and their characteristics depend on the particular application and related stresses and loads, as well as the long-term effect from their application for example, specific requirements for the non-woven items in car construction are their light resistance and temperature resistance [40].

Non-woven textiles in cars and other means of transport may influence all six basic metrics of the Indoor Environmental Quality, including the Indoor Vibration Quality (IVQ), which is rarely discussed in the case of built environment. The way the non-woven items in cars affect the IEQ is similar to the application of non-woven textiles in buildings, where they are used as upholstery coverings, floor coverings, backing, etc.

The level of emissions from all items in the interior of the car, including the non-wovens, is important for both the IEQ and the fogging, which may occur. All non-wovens have to be environmental friendly with low emissivity, including in cases of extreme indoor tempera‐ tures. Therefore, the car industry takes special care to use materials that have low emission potential, either as release of volatile chemicals (VOCs, SVOCs, VVOCs) or as reaction products. The last is closely related with the temperature and partial pressure drop.

The Indoor Odor Quality (IOQ) in cars is influenced by the non-wovens applied and is preconditioned in many cases by the emission of substances that influence the IAQ [41,42]. The emissions frequently occur at high temperatures only, but due to condensation on flat surfaces (mainly the windscreen and side windows) they form unacceptable fogging.

Non-woven materials in the car are used for thermal and acoustic insulation, thus improving the Indoor Thermal Quality and Indoor Sound Quality not only in the car compartment, but also in the boot and the engine housing. The main insulated parts are the dashboard, the roof, and the floor, the side walls and the rare wall, the parcel shelf, the doors, the tailgate, the ABC pillars, the boot sides, the air-conditioning conduit, etc. [39]. Non-woven textiles made of recycled natural fibers are still competing with polyurethane foams for being used as insulation materials in cars. Chemically bonded fiber webs with volume densities from 50 to 150 kg/m3 are used for acoustic insulation [39]. At the same time, high-density webs are applied for production of car components like the roof or the parcel shelf, which can emit strong-smelling amines immediately after the installment. According to the study in [42], these emissions decrease rapidly after days, eliminating their negative effect on the IOQ.

are used, like Technostat ® needle-punch felt media [38]. Glass microfiber HEPA filters, filter media of blends between synthetic and glass fibers, as well as composites with non-woven media are also in use. Non-woven felts from a mixture of natural and synthetic fibers are

In their role of filter media non-woven materials can influence the Indoor Air Quality (IAQ) and indoor odor quality (IOQ). HVAC systems and air purifiers increase the quality of the indoor environment when working properly and maintained correctly. Noncompliance with the requirements for cleaning or replacement of the particular filter media can lead to change of the indoor environmental quality for the worse. The main reasons are either the incapacity of the filters to retain dust and particles, or the growth of airborne microbial contaminants, which are spread from the filter media to the air of the enclosure, leading to increment of VOCs,

The use of non-woven textiles in the sector of transportation is growing and the car industry is leading this trend. A number of applications of non-wovens in car construction are described in details in [39,40]: lining of doors boot and hoodcase, seat construction (including upholstery cover), filters, engine housing, etc. The requirements for the types of the non-wovens used and their characteristics depend on the particular application and related stresses and loads, as well as the long-term effect from their application for example, specific requirements for the non-woven items in car construction are their light resistance and temperature resistance [40]. Non-woven textiles in cars and other means of transport may influence all six basic metrics of the Indoor Environmental Quality, including the Indoor Vibration Quality (IVQ), which is rarely discussed in the case of built environment. The way the non-woven items in cars affect the IEQ is similar to the application of non-woven textiles in buildings, where they are used

The level of emissions from all items in the interior of the car, including the non-wovens, is important for both the IEQ and the fogging, which may occur. All non-wovens have to be environmental friendly with low emissivity, including in cases of extreme indoor tempera‐ tures. Therefore, the car industry takes special care to use materials that have low emission potential, either as release of volatile chemicals (VOCs, SVOCs, VVOCs) or as reaction

The Indoor Odor Quality (IOQ) in cars is influenced by the non-wovens applied and is preconditioned in many cases by the emission of substances that influence the IAQ [41,42]. The emissions frequently occur at high temperatures only, but due to condensation on flat

Non-woven materials in the car are used for thermal and acoustic insulation, thus improving the Indoor Thermal Quality and Indoor Sound Quality not only in the car compartment, but also in the boot and the engine housing. The main insulated parts are the dashboard, the roof, and the floor, the side walls and the rare wall, the parcel shelf, the doors, the tailgate, the ABC pillars, the boot sides, the air-conditioning conduit, etc. [39]. Non-woven textiles made of

products. The last is closely related with the temperature and partial pressure drop.

surfaces (mainly the windscreen and side windows) they form unacceptable fogging.

applied for a backing support [38].

198 Non-woven Fabrics

**4.6. Non-woven textiles in cars**

MVOCs, and other pollutants of the indoor environment.

as upholstery coverings, floor coverings, backing, etc.

Thermally bonded non-wovens with volume densities from 40 to 130 kg/m3 from polypropy‐ lene fibers have been developed in order to replace the chemically bonded cotton webs and to avoid the undesired emission inside the cars [39]. These non-woven insulations demonstrate less fogging capacity and lower emissions.

Thermally bonded non-wovens with special shape of the fiber cross section (triangular, starshaped, etc.) are also used to improve the Indoor Sound Quality.

Non-woven textiles of different type are widely used as covers in car compartments: needlepunched, spunbonded with reinforcement, thermally bonded, or meltblown non-wovens. Tufted fabrics are applied as floor coverings and light non-woven webs are also used as backing of the tufted floor coverings. Needle-punched fabrics are also in use, but for cheaper car models. In any case, cut pile of the tufted floor coverings are preferable than the loop pile, which accumulates more dust and particulate matter.

The analysis of the market and the research in the field, including the patents, show that much more effort, know-how, and economical support are put in the development of non-woven fabrics for car interiors than for the interior of buildings. Therefore, new materials and blends, methods for bonding, lamination, and new composite materials can be found much more in the car production industry than in the construction of buildings. The driving force of one of the biggest industries in the world – the automotive industry – is of particular importance for the advances in the field of non-woven textiles.
