Yaa Hydroentanglement Bonding Procedure For Production Of Nonwoven Stuff (Part-2)

Hydro-entanglement Bonding Process for Production of Nonwoven Fabric (Part-2)

Eng Mohamed Elsharkawy
Dept. of Textile Engineering
Alexandria University
Alexandria, Arab Republic of Egypt
Email: m.elsharkawy.tex@gmail.com

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Principle of producing non-woven fabric:
Nonwovens are typically manufactured yesteryear putting small-scale fibers together inwards the cast of a canvas or spider web (similar to newspaper on a newspaper machine), as well as hence binding them either mechanically (as inwards the representative of felt, yesteryear interlocking them amongst serrated needles such that the inter-fiber friction results inwards a stronger fabric), amongst an adhesive, or thermally (by applying binder (in the cast of powder, paste, or polymer melt) as well as melting the binder onto the spider web yesteryear increasing temperature) [2].

2.3. Hydro-entanglement procedure
Hydro-entanglement is a mechanical bonding procedure designed to make nonwoven fabrics amongst texture as well as appearance that resemble woven as well as knitted fabrics.

In a typical hydro-entanglement process, a row or multiple rows of highly pressurized, fine, closely spaced H2O jets impinge on a fiber spider web which is supported yesteryear forming wires. Due to the touching of H2O jets, fibers from the surface are inserted into the fibrous web, as well as fibers are displaced as well as rotated approximately other fibers that environs them, resulting inwards fibers twisting as well as entangling approximately the neighboring fibers. The cloth produced is held together yesteryear the fiber-to-fiber friction [3, 4].

Fibers are carded inwards the carding machine as well as entangled inwards the hydro-entangling unit. After hydro-entanglement, the H2O inwards the fabrics is removed through the drying process. There is a finishing process if desired, as well as the fabrics are hence injure on rolls for time to come processing.

2.4. Methodology of hydro-entanglement
Spun-lacing is a procedure of entangling a spider web of loose fibers on a porous belt or moving perforated or patterned hide to cast a canvas construction yesteryear subjecting the fibers to multiple rows of fine high-pressure jets of water. Various steps are of importance inwards the hydro-entangling procedure [5, 6].

Figure (2.3): Principle of hydro-entanglement

While some of them are typical inwards a nonwoven process, some of them are unique to the procedure of spun-lacing. The steps feature for producing hydro-entangled nonwoven cloth include:

• Precursor spider web formation
• Web entanglement
• Water circulation
• Web drying

The formed spider web (usually air-laid or wet-laid, but sometimes spun bond or melt-blown, etc.) is rootage compacted as well as pre-wetted to eliminate air pockets as well as hence water-needled. The H2O pressure level to a greater extent than ofttimes than non increases from the rootage to the terminal injectors which are used to straight the H2O jets onto the web.

This pressure level is sufficient for virtually nonwoven fibers, although higher pressures are used inwards specialized applications. It has been argued that 10 rows of injectors (five from each side of the fabric) should attain consummate cloth bonding [5].

Injector hole diameters attain from 100-120 µm as well as the holes are arranged inwards rows amongst 3-5 mm spacing, amongst i row containing 30-80 holes per 25 mm [7].

The impinging of the H2O jets on the spider web causes the entanglement of fibers. The jets exhaust virtually of the kinetic liberate energy primarily inwards rearranging fibers inside the spider web and, secondly, inwards rebounding against the substrates, dissipating liberate energy to the fibers.

A vacuum inside the curlicue removes used H2O from the product, preventing flooding of the production as well as reduction inwards the effectiveness of the jets to motion the fibers as well as crusade entanglement.

Usually, hydro-entanglement is applied on both sides inwards a step-wise manner. As described inwards the literature[8] , the rootage entanglement curlicue acts on the rootage side a publish of times inwards club to impart to the spider web the desired amount of bonding as well as strength.

The spider web hence passes over a minute entanglement curlicue inwards a contrary management inwards club to care for and, thereby, consolidate the other side of the fabric. The hydro-entangled production is hence passed through a dewatering device where excess H2O is removed as well as the cloth is dried.

Figure (2.4): Description of procedure

Hydro-entanglement carried out at touchstone weather condition (six manifolds of needles, 1500 psi, as well as spider web weighing 68 g /m2) requires 800 pounds of H2O per pound of production [9].

For that ground it is necessary to prepare a novel filtration organization able to effectively render build clean H2O amongst this high throughput; otherwise, H2O jet holes operate clogged. This organization consists of iii stages: chemic mixing as well as flocculation, dissolved air flotation as well as sand filtration [9]. Spun-laced fabrics convey led to a lot of speculation regarding their industry because virtually of the manufacturing procedure details are considered every bit proprietary [10].

2.5. Materials used inwards hydro-entanglement
As previously mentioned, hydro-entanglement could live carried out using dry-laid (carded or air-laid) or wet-laid webs every bit a precursor. Most commonly, precursors are mixtures of cellulose as well as man-made fibers (PET, nylon, acrylics, Kevlar, etc.

In addition, nosotros tin role rattling fine fibers produced from divide tabular array composite fibers to make hydro-entangled substrates for synthetic suede leather products.

In general, cellulosic fibers are preferred for their high strength, pliability, plastic deformation resistance as well as H2O insolubility. Cellulosic fibers are hydrophilic, chemically stable as well as relatively colorless. Another payoff is that cellulose has an inherent bonding mightiness caused yesteryear a high content of hydroxyl groups, which attract H2O molecules. As the H2O evaporates from the fabric, the hydroxyl groups on fiber surface link together yesteryear hydrogen bonds [9].

Influence of cotton fiber micronaire on cloth properties has been studied. Generally, depression micronaire cotton fiber is non recommended for hydro-entangled nonwovens because of higher publish of neps as well as small-scale bundles of entangled fibers, resulting inwards unsightly appearing fabric.

In spite of this, fabrics made amongst lower micronaire fiber demo higher strength, belike caused yesteryear a higher publish of fine fibers as well as greater surface expanse [9].

In addition, greige cotton fiber has been used inwards spun-lacing technology. It has been shown that the absorbency charge per unit of measurement increases amongst increasing hydro-entangling energy. This is the final result of crude as well as wax removal from the fiber surface. These nonwovens tin live later on bleached, which should enhance the forcefulness of the cloth [9].

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