Fabric air permeability is a measure to what extent it gives air passing through the fabric. The porosity of fabric is the demonstration of the air gap as a percentage within the fabric. It has been important for especially the tent fabric and parachute. Knitting Expo will introduce you the level of textile fabrics ’s air permeability differs depending on the following.
I. Fabric Structure: Woven fabric specifications
Fabric construction: –warp count x weft count/ends per inch x picks per inch
Fabric area density/GSM
Cover factor—changing the area density and/or the cover factor may affect strength, stiffness, stability, porosity, filtering quality and abrasion resistance of fabric. Application of jammed fabrics or closely woven fabrics finds use in waterproof, windproof, bulletproof requirements.
Type of weave
Crimp
Fabric width
thickness
Under the same tightness of the fabric, the air permeability of the fabric is inversely proportional to the yarn density; from the aspect of the texture of the fabric, under the same arrangement density and tightness, the air permeability is ranked as plain weave/twill/satin/porous structure; the fabric with a larger volume fraction has a lower air permeability.
II. Fibre Properties
Type of interlace, type of fibre (spun or strand), size of the fibre (Linear toughness), twist factor in the fibre, strand toughness (ends and picks) and fold are other material parameters that affect the air permeability of a material. Moreover, the moisture regains of the fibre has a significant effect on the air permeability.
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When the wool fabric increases with the moisture regain, the air permeability drops significantly due to the radial expansion of the fibre. The surface shape and cross-sectional shape of the fibre will increase the resistance of the airflow due to the increase of the shape barrier and the specific surface machine: The shorter the fibre, the greater the rigidity as well as the probability of product hairiness, hence the poorer the air permeability.
III. Yarn Structure
The tighter the structure of the yarn, the smaller the penetration within the yarn but the greater the penetration between the yarns. The material, twist and smoothness of the yarn contributes to permeability. The material type and amount of yarn twist, count and yarn structure manufactured by Ring spinning, Open end, Air textured, condenser spinning methods does impact on fabric air permeability. Some important parameters related are pore in the fabric were taken in to account like the cross-section of the pore, depth of pore or thickness of fabric and number of pores per unit area.
IV. Environmental Conditions
Under the constant temperature, the air permeability of the fabric decreases with the increase of relative humidity, due to the hygroscopic expansion of the fibres which reduces the internal voids of the fabric and some moisture can block the passage. Under the constant relative humidity, the air permeability of the fabric increases as the ambient temperature increases. Because when the ambient temperature rises, on the one hand, the thermal motion of the gas molecules is intensified, leading to the diffusion of molecules, which enhances the permeability. On the other hand, the thermal expansion of the fabric as a whole improves the permeability of the fabric.
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V. Other Aspect
Besides the above, air permeability of material also hangs on parameters like the material cover and material permeability. Sum cover of material is known as the ratio area concealed by the covering and the stuffing fibres to the area concealed by the material. The kind of knit decides the way in which the fibres are twisted in the material. The air permeability of the materials can be altered by changing the way of knitting. When the size of the fibre changes, the same happen in the fibre of the material hence the permeability of the material changes.
Advanced fabric production project demands developing strategies with regard to new fabric constructions and it should have the desired end-usage properties as per there applications. For specified Fabric, we need to have complete knowledge and understanding of porous barrier between the human body and environment. This should support heat and water vapour exchange between the body and environment in order to keep the body temperature within the homeostasis range.
Besides thermo-physiological protection, fabrics also play an important role by heat protection due to the flames or convection heat, contact heat, radiant heat as well as due to the sparks and drops of molten metal, hot gases and vapours.
Source: textile school
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The Como, Italy-based textile company is debuting Resilk, an upcycled silk fabric.
As the whole fashion system is in flux due to the COVID-19 pandemic, companies are reevaluating their priorities — and putting sustainability at the core of their activities.
Como, Italy-based silk specialist Mantero Seta SpA has found more than one reason during lockdown to step up its sustainable commitment, as part of its Respect program of social corporate responsibility initiatives.
First of all, it is important to define the similarities but also the differences between a virus and a bacteria to clarify the purpose of antiviral and antibacterial fabrics.
Bacteria are unicellular organisms. They are living cells that can be either beneficial or harmful to other organisms. Viruses, on the other hand, are considered to be particles that are somewhere between living and nonliving cells. Viruses have to invade the body of a host organism in order to replicate their particles.
A bacterium can survive on its own, inside or outside the body. Most bacteria aren’t harmful. Most viruses are pathogenic.
Therefore, the purpose of antiviral versus antibacterial fabrics are slightly different. Bacteria in a fabric is more of a nuisance rather than a threat as they — in combination with moisture emitted from our body — can start to stink, and the more bacteria live in our clothing, the more annoying this can get, but normally the consequences are not pathogenic. Hence, the main purpose of an antibacterial fabric is to inhibit the growth of bacteria to keep a fabric fresh to wear for many days or nights without the need of washing it daily after wearing.
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On the other hand, viruses — needless to say, these days — are more than a nuisance. Hence, the purpose of an antiviral fabric is to inhibit any kind of host cells that a virus has or can invade on the fabric, waiting for a passage to the doors of our body. And given the potentially lethal consequence of a virus, there is a different level of testing and certification needed that a fabric can qualify to be antiviral.
Four years in the making, the company has introduced the Resilk regenerated fabric developed in partnership with solution provider Marchi & Fildi. The idea stemmed from the need to upcycle pre-consumer deadstock coming from the fabrics’ selection, as the company’s clients — including luxury fashion brands, which often ask for exclusive textiles — would not accept those with flaws, consequently forcing the brand to burn them.
“The project has a sustainable silver lining in all its aspects, preventing us from burning economic, ethical and environmental assets,” noted Franco Mantero, the company’s chief executive officer, and the fourth generation of the founding family.
Unwanted 100 percent silk fabrics are destroyed through mechanical processes to obtain a new yarn that is GRS-certified and weaved into new textiles that boast the same gleam of silk but feel like cashmere for their softness. The Resilk fabric is suitable for women’s and men’s wear as well as for upholstery and Mantero said its price is in line with similar textiles.
The fabric is employed for a capsule collection of garments within the fall collection of the company’s owned Mantero 1902 brand.
“The pandemic has convinced us that we need to reevaluate the way we live and the way we do business, which might be in sharp contrast with the essence of luxury itself, in which the goal is to obtain a product that is as perfect as it can be,” noted Mantero. To this end, he added that the eco-friendly component should come hand in hand with a good design and quality, as commercial success cannot rely on the green aspect only.
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Mantero’s eco-friendly efforts are extended to the entire production process — of regular silk for scarves and ties that are ZDHC-certified — by avoiding harmful chemicals and relying on a system that reduces CO2 emissions, as well as photovoltaic panels, currently supplying 20 percent of the company’s energetic needs. A cogeneration system will bring the quota up to 80 percent in the next few years.
All these measures are “even more important in the wake of COVID-19, which forced us to reevaluate our priorities, keeping the same goals we already had but giving a different priority to each of them,” Mantero contended.
The company’s broader CSR program is intended to promote a sustainable and responsible way of doing business across finance, workforce, the environment and the products, in sync with the United Nations’ SDGs.
To this end, Mantero has brought on board a younger workforce with 100 employees under 30 especially in the design department coming from fashion schools such as Milan’s Naba and Istituto Marangoni and London’s Royal College of Arts, among others. It has also partnered with the U.N.’s UNHCR program aimed at offering a chance and job to refugees coming from Ethiopia, Syria, Pakistan and Mali, with “personal stories that are very different from what we’re used to,” Mantero said.
For more industry information, please pay attention to Knitting Fair.
Source: WWD
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