Non-wovens Application

Non-wovens are described as flat, porous sheet or web structures produced by binding and interlocking fibers, yarns, or filaments by mechanical, thermal, chemical, or solvent means. They are porous sheets that are made directly from separate fibers, molten plastic or plastic film. They are not made by weaving or knitting and do not require converting the fibers to yarn. 

Non-woven fabrics are engineered fabrics that may be of single-use, limited life, or very durable. They provide specific functions such as absorbency, liquid repellency, resilience, stretch, softness, strength, flame retardancy, washability, cushioning, filtering, bacterial barrier and sterility. These properties are often combined to create fabrics suited for specific jobs, while achieving a good balance between product use-life and cost. 

In combination with other materials, non-woven fabrics provide a spectrum of products with diverse properties, and are used alone or as components of apparel, home furnishing, health care, engineering, industrial, and consumer goods. They are categorized according to application as either disposables or durables. Some familiar products made with non-wovens are listed in Tab. 10-1 [1-3]. 

The worldwide production of non-wovens is estimated at 2.7 million tons (or 6.0 billion poimds) in 1999 [4—6]. Western Europe accounts for approximately 35 % of the world production of non-woven products, followed by North America (30 %), China (12 %), Japan (12 %) and others, as shown in Fig. 10-1. The value of non-woven product shipment in North America reached an aU-time high in 1997 with an approximate value of 2.8 billion [7] and disposables account for nearly 70 % in value. The non-woven industry in North America is expected to grow at 2-3 % annually and to be 3.2 biUion in 2002. 

China and Japan dominate non-wovens production in Asia followed by Taiwan and Korea as shown in Fig. 10-2. Double-digit growth is expected in these countries, and production in China and Japan reached to 350 000 tons each in 2000 with an an- 

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The primary non-woven applications for hot melts are in disposable articles such as diapers and sanitary napkins (see Fig. 22). These articles are made by high speed processes and are immediately packaged in sealed plastic bags, thus they are prime candidates for hot melt use. The applications are broken down into three categories, requiring three different types of adhesives construction, elastic attachment, and garment attachment. 

A majority of the acrylic emulsion polymers used in textile and non-woven applications are crosslinked or cured after film formation to provide wet stroigth, solvent resistance and durability to laundering and dry cleaning. As with architectural coatings binders, the principal monomers used are BA, EA and MMA,... 

Fig. 10-5 Non-woven applications in North America, Europe and Japan are compared by weight of products in 1999. Hygiene, medicai and wipes account for greater than 50 % in aii these continents.

Non-woven fabrics can be produced very economically, which suits them for many singleuse health and hygiene applications, such as the outer cover and body contacting layers of... 

Other potential applications of PTT are in monofilaments, non-wovens, films, engineering thermoplastics and molded goods. Hsu [80] has patented paper forming fabrics made with PTT monofilaments for use in papermaking machines because this combines the chemical resistance of a polyester and the resiliency... 

The newest commercial polymer to join the polyester family is poly(trimethylene terephthalate) (PTT) which is being targeted at fibre applications (Chapter 11). It is sold under the Corterra trademark by Shell. After packaging, the single largest use for polyesters is for fibre applications such as clothing, textiles and non-wovens. The technology of polyester fibre formation is described in Chapters 12 and 13. 

For the sake of discussion, we have divided the separators into six types—microporous films, non-wovens, ion exchange membranes, supported liquid membranes, solid polymer electrolytes, and solid ion conductors. A brief description of each type of separator and their application in batteries are discussed below. 

Common uses for polyester resins are reinforced plastics automotive parts boat hulls foams encapsulation of electrical equipment protective coatings ducts flues and other structural applications low pressure laminates magnetic tapes piping bottles non-woven disposable filters and low-temperature mortars. 

It is readily imaginable that this process can be transferred into a continuous partially automated procedure similar to a non-woven line. The new production process will also permit the broad availability of catalysts on micro structures. A wide application of these catalysts was up to now hindered by the costs per unit and the non-existent technology for industrial production. The process is also applicable to heat exchangers, which can just be considered as uncoated reactors. 

Continuous coating is a well-established process in the non-woven industry. Non-woven textiles reach their final product quality tensile strength, resistance against humidity or surface structure only after the application of appropriate additives to the surface or interior of the textile. In principle, a number of methods are convenient, as shown in Figure 4.107 [167]. 

Figure 4.107 Methods for the application of binder to a non-woven web [167] (by courtesy of Georg Thieme Verlag.

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