Polypropylene disposable diapers

Such repositioning inevitably means reduced production volume, and for the first time this century production in the last decade has been below that a decade earUer (Eig. 9). Most capacity reductions have been in North America and especiaUy eastern Europe. This has been offset in part by capacity increases in the Ear East. Rayon is no longer a significant component of carpets, and has lost the disposable diaper coverstock business to cheaper and more easUy processed polypropylene. It has, however, gained share in health and hygiene products and is now a principal component of tampons worldwide. 

In the United States, fibers and injection mol ding are the main appHcations for polypropylene (Table 8), followed by film. In Europe and Japan, injection mol ding appHcations predominate (Table 10). This market area is more likely to decline in economic recession, as consumers postpone purchases of apphances and automobiles. Film appHcations are important in both regions, but fibers are a much less important use for polypropylene in Japan than in other developed regions. The heavy use of polypropylene nonwovens in the manufacture of disposable diapers and similar products, and the wide use of polypropylene carpets in the United States, account for the greater consumption of fibers. 

Disposable polypropylene nonwoven fabrics are widely used as the coverstock for disposable baby diapers. The expansion of the disposable diaper market throughout the world has been the primary source of growth in the consumption of polypropylene in the fiber market. In addition, nonwoven polypropylene fabrics are used in a variety of other disposable sanitary products, such as baby wipes, adult incontinence, and feminine hygiene products. Use of polypropylene nonwovens in disposable medical apparel, such as surgical gowns, has increased as a means of reducing the spread of infection. 

Polypropylene (PP) is used in a variety of areas, from snack food packaging to battery cases to disposable diaper linings. It is frequently interchanged for polyethylene or polystyrene. 

Disposables are also considered to be an environmental threat. Only some of the materials used in the diapers are biodegradable (the wood pulp and SAP). The polyethylene and polyester sheets are not biodegradable neither is the elastic used for better fit, nor the polypropylene used for the tape that is employed as a fastener. Disposable diapers account for up to 2 percent of the total volume of landfills in the United States. The lifetime of the diaper in the landfill depends on several environmental factors soil condition, groundwater flow, and the presence of other materials in the soil. see also Matertals Science Polymers, Synthetic. 

One of the studies of cloth diapers assumed a life of 92 uses (a study funded by the disposable industry), whereas the other assumed 167 uses (a study funded by the cloth diaper industry). A study funded by the disposable diaper industry assumed an energy cost for transporting the cotton to China where the diapers were made. One would have to check to see what fraction of cloth diapers are made this way. Disposable diaper makers have pushed composting as a method of disposal. Most cities do not compost this type of waste. The polyolefins would not degrade well in this process, even though the lack of stabilizers in the polypropylene might allow it to become powder. 

Typical applications for homopolymer polypropylene include windshield washer tanks, shrouds for fans and steering columns, housings for domestic appliances such as hair dryers, sterilisers, irons, coffee makers, toasters, etc., extrusion of fibres and filaments for carpet backing, upholstery fabrics, clothing, geotextiles, disposable diapers, medical fabric and automotive interior fabrics. 

Nonwoven products are usually constructed of polyethylene and polypropylene materials which are very hard to adhere to. In spite of this, hot melt adhesives are used almost exclusively to bond most structures. Diapers represent the largest product line using hot melt adhesives. In the fiiture it may be that incontinent diapers and absorbent pads will be an even larger market. EVA-based hot melts are believed to hold about 60% of the market, with low molecular weight polyethylene and atactic polypropylene making up the remainder. The type of adhesive used is constantly under change as the performance requirements change. The disposable diaper has penetrated approximately 80% of the total diaper market. 

About 40 percent of polypropylene resin is extruded into fiber and filament, coatings, film, sheet, pipe, and wire insulation. The fiber does not absorb water and is stain- and abrasion-resistant. The largest market for polypropylene fiber is for carpet backing. The fiber also is used to make disposable diapers and other nonwoven fabrics. Because of its strength, lightness, and resistance to weathering and microorganisms, it has replaced natural fiber in rope and cord. 

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