Spunbonding process

In the spunbond process (Fig. 10), an aspiratory is used to draw the fibers in spinning and directiy deposit them as a web of continuous, randomly oriented filaments onto a moving conveyor belt. In the meltblown process (Fig. 11), high velocity air is used to draw the extmded melt into fine-denier fibers that are laid down in a continuous web on a collector dmm. 

In the spunbond process, the fiber is spun similarly to conventional melt spinning, but the fibers are attenuated by air drag appHed at a distance from the spinneret. This allows a reasonably high level of filament orientation to be developed. The fibers are directly deposited onto a moving conveyor belt as a web of continuous randomly oriented filaments. As with meltblown webs, the fibers are usually thermal bonded or needled (53). 

Spunbonded processes, 17 463 Spunbonded structures, novel, 17 466 Spunbound fibers, 11 236, 240-241 Spun fibers, 16 18, 20 Spunlaced nonwovens, 17 507 Spunlace fabrics, production of, 17 516 Spun yarn, 11 177, 178, 250. See also Yarn spinning technologies crystalline structure of, 11 237-238 Spurrite (5-calcium disilicate monocarbonate)... 

Spunbonding Process of producing a bond between nonwoven fibers by heating the fibers to near their melting point. 

Most spunbonded processes yield a sheet having planar-isotropic properties owing to the random laydown of the fibers (Table 2). Unlike woven fabrics, spunbonded sheets are generally nondirectional and can be cut and used without concern for higher stretching in the bias direction or unraveling at the edges. 

The physical properties of flashspun fabrics are unique and not attainable via the melt-spun spunbond process. Even bicomponent melt spinning cannot produce similar structures. As a result the profitability of a fiashspun operation is very high when the capacity of a line is fully utilized. 

Tandler B, Schmack G, Vogel R, Blechschmidt D, Lindner R. Melt processing of a new biodegradable synthetic polymer in high-speed spinning and imderpressure spunbonding process. Journal of Polymers and the Environment 2001 9 149-56. 

The spunbond process is a nonwoven manufacmring system involving direct conversion of a polymer into continuous filaments, integrated with the conversion of the filaments into a random laid nonwoven fabric. Examples for the used technologies are shown in the Figs 5.1—5.4. 

The polymer most commonly used in spunbond processes is PP. There are many usable types of PPs available on the market. These have a controlled rheology with... 

Besides these general procedures, applied to the production of PO fibers before 1965, other modem ways have been developed and used for melt spinning. They include high and ultrahigh speed spinning, the split-film method, the spunbond process, and the melt-blown system. 

Compared with the spunbond process, the melt-blown system (spray method) produces microdenier (sprayed) fibers. Molten or dissolved fiber-forming PO polymers are forced with a spray gun or through a multiple-hole extruder to disrupt the filament into a high velocity hot air jet, to form superfine fibers less... 

The conventional fiber producing route (long system) is essential for the production of certain types of continuous filament and for the equipment used in association with the spunbonding process. 

In the spunbonded process, filament formation can be accomplished with one large spinneret having several thousands holes or with banks of smaller spinnerets containing at least 40 holes. After exiting the spinneret, the molten filaments are quenehed by a cross-flow air system, then pulled away from the spinneret and attenuated (drawn) by high pressure air. 

The Lurgi Docan spunbonded process (Lurgj and Mineraloltechnik GmbH, Germany) [82] is a one-step operation in which a random web is formed by spinning and drawing continuous filaments, which are then... 

Spunbond process Spunbonded nonwovens (spunbonds or spinbonds)... 

Spunbond processes and fabrics have been commercial for over 40 years. The processes, fabrics, and markets are quite varied. The best known spunbond fabrics and markets are cover stock for diapers and feminine hygiene products. However, spunbond fabrics are also found in carpet backing, geotextiles, furniture dust covers, carriers for fabric softeners, and a host of other industrial and consumer applications. The key to most of these markets has been a low cost covering material with sufficient tensile and opacity properties to fit the application. The latest market trend is towards pre-wetted wipes for cleaning and similar uses. The product needs for this fabric include short term abrasion resistance and ability to hold solvents. 

As the new century began, we saw new beginnings in spunbond processes and products. New techniques are being developed to improve uniformity and barrier properties of spunbond fabrics to allow spunbond to compete successfully with carded thermal bonded nonwovens. Fabrics from new polymers and polymer combinations are poised to enter the market. Tactile as well as tensile properties are being improved to the point where even apparel applications may be considered as a future market (Anon., 2011). Several of these trends are described in the following paragraphs. 

In the past 10 years, electrospun nanofibrous membranes have been spotlighted as an effective filter media to capture fine particles. In addition to the basic studies of electrospinning process to better understand the membrane construction process, researchers from all over the world focus on the study of the relationships between the structure characteristics of electrospun nanofibrous membranes (fiber diameter, pore size, porosity, surface area, etc.) and filtration performances (filtration efficiency, pressure, air permeability, etc.). In this chapter, recent advances in fabricating nanofibrous filter media via electrospinning process have been reviewed. In particular, filtration performances and relevant mechanical properties are discussed in detail. It is interesting that the electrospun nanofibrous membranes have been able to outperform conventional nonwoven membranes fabricated essentially by using the meltblown or spunbonded process. 

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