Nonwoven fabrics meltblown nonwovens

Extmsion technology is used to produce spunbond, meltblown, and porous-film nonwovens. Fabrics produced by these systems are referred to individually as spunbonded, meltblown, and textured- or apertured-film nonwovens, or genericaHy as polymer-laid nonwovens. These fabrics are produced with machinery associated with such polymer extmsion methods as melt-spinning, film casting, and extmsion coating. In polymer-laid systems, fiber stmctures are simultaneously formed and manipulated. 

The uses of spunbonded fabrics as coverstock in diapers and other personal absorbent devices will most likely remain unchallenged for the near term. Virtually any other nonwoven production method appears to be at a cost disadvantage opposite spunbonded polypropylene. There have been composite products developed from meltblown and spunbonded combinations, where areas of either improved hydrophobicity or hydrophilicity are desired. These products can be produced on-line at relatively low additional cost and offer high value to diaper manufacturers. Any competitive threat is likely to come from advances in film technology such as large improvements in perforated film used in segments of absorbent product appHcations, particularly sanitary napkins. 

Nonwoven geotextiles. Nonwoven fabrics are defined as a sheet, web, or batt of directionally or randomly oriented fibres/filaments, bonded either by friction, and/or cohesion, and/or adhesion. In general, nonwoven fabric formation can be considered as a two-step process web formation (aligning the fibres with certain orientation characteristics) and bonding these fibres by mechanical, thermal, or chemical means. This two-step process has formed the classification of nonwoven structures, i.e. carded, airlaid, spunlaid, meltblown, needlepunched, hydroentangled, adhesive bonded, thermal bonded, stitch bonded, etc. Some of the important processes that are used for the manufacture of nonwoven geotextiles are discussed below. 

Extrusion-Formed Webs. Examples include spunbonded and meltblown. Extmsion technology is used to produce spunbond, meltblown and porous-film nonwovens. These fabrics are made with machinery associated with polymer... 

In the spimbond process, the fiber is spim similarly to conventional melt spinning, but the fibers are attenuated by air drag applied at a distance from the spinneret (see Nonwoven Fabrics). 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). 

Tsai P P, Ghen W and Roth J R (2004) Investigation of the fiber, bulk, and surface properties of meltblown and electrospun polymeric fabrics. Intern Nonwovens J 13 17-23. 

These products are used to wrap and pack surgical instruments ready for sterilisation ahead of theatre use. Traditionally, the market used paper-based sterilisation wraps, either crepe or plain MG (INDA, Association of the Nonwoven Fabrics Industry) papers. Some parts of the market are now transitioning towards SSMMSS (SSMMSS is a composite of spunbond and meltblown nonwoven proceses) polypropylene composite materials [7]. 

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. 

Panel filters can be made from any material that can be pleated, without cracking along the fold cellulose or glass paper, fine wire cloth, woven fabrics, nonwoven fabrics of all kinds (felts, spunbonds, meltblown) and membranes. Charcoal cloth can also be used, provided that it is pleated before charring. Synthetic fibre media are most common, having shown themselves well suited to the ventilation of a wide variety of buildings domestic, commercial, institutional and industrial. 

---