Nonwoven production

Several more recent variations of the film-to-fiber approach result in direct conversion of film to fabric. The film may be embossed in a controlled pattern and subsequently drawn uniaxiaHy or biaxiaHy to produce a variety of nonwoven products (47). Addition of chemical blowing agents to the film causes fibrillation upon extmsion. Nonwovens can be formed directly from blown film using a unique radial die and control of the biaxial draw ratio (48)... 

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 products ranging from medical disposables to automotive fabrics are required to meet specific flammability standards. These fabrics are generally composed of cellulosic and/or synthetic fibers which are flammable. Additionally, polymer coatings are applied to the fabric to impart properties such as strength, abrasion resistance and overall binding. It is the purpose of this paper to describe the various polymer coatings commonly used in the nonwovens industry and their effect on flammability of the substrates. Additionally, the effect of flame retardant additives, commonly used in latex formulations, will be discussed. 

MANGO YANNICH Flame-Retardant Latices for Nonwoven Products... 

Nonwoven fibrous products are cheaper to produce because the number of steps required is small. Weaving, on the other hand, can be very complex and consequently expensive. Nonwoven products such as mats are porous and have lower strength and flexibility compared to the woven fabrics. Nonwovens can be made by a variety of different methods ... 

The spray test is one of the most commonly used tests for fabrics and nonwoven products. The test material is held tightly on an embroidery hoop and mounted at a 45° angle to the horizontal and 15 cm below a spray nozzle. The fabric is sprayed with 250 ml. of water. The degree of repeUency is rated by comparing the sprayed fabric or nonwoven with pictures on a standard chart (AATCC Test Method 22 (7) INDA Standard Test 80.1-92 (40)). DurabUity of the finish to dry cleaning can be evaluated by first cleaning the fabric according to AATCC Method 86 (14). 

The melting point of polypropylene is an advantage in many new nonwoven products. Polypropylene fibers can be melted sufficiently to bond to one another without destroying fiber properties. Nonwoven fabrics made from polypropylene can, therefore, be fusion-bonded. 

Countries that are major producers of nonwoven products have heavily used these products in health and medical applications. According to 1999 statistics, 38% by weight was devoted to these usages in West Europe, 31% in the United States, and 23% in Japan. 

It is estimated that the worldwide consumption of nonwoven products will reach 6.3 MT by 2010, of which Europe and the United States will account for 55%. With a rapid annual growth of 10%, China will contribute about 24% of this productivity. 

Polypropylene accounted for about half of the nonwoven products in industrial uses in 2001. Its share in ropes and nets was 55-60%, and 70-80% in civil construction, where polyester claimed 20-24%. In automotive applications, polypropylene shared 26-30%, nylon almost 50%, and polyester about 20%. Polypropylene contributed to over 86% of agricultural nonwoven, 100% of packaging cloth, 85% of sanitary items, and 64-70% of medical applications. The world consumption of industrial nonwoven products was 1.329 MT in 2000. Polypropylene topped all synthetic fibers with a share of over 40% in this market segment. 

Nonwoven products for use in civil construction amounted to 1.4% in 1985 and increased to 2.3% in 1995. In 1995, about 196 KT of nonwoven construction fabrics were consumed in the United States, 140 KT in West Europe, and 15 KT in Japan. Its market share is estimated to increase to 3.5% by 2005. This growth has been attributed to the wide adoption of nonwoven products in engineering projects on rocky grounds. 

Industrial uses industrial products, medical surgical products, nonwoven products, tire cord. 

Table 3.2 Some common characteristics of nonwoven production processes...

The nonwoven fabrics are very versatile materials and are being extensively used for gas and liquid filter appUcations, including pharmaceuticals, food and drink, vacuum cleaners, and industrial applications. Within the automotive industry, there are performance considerations, including pollution reduction and bacterial protection combined with lower weight and the environmental impact. These requirements can be fulfilled with the use of a range of versatile nonwoven production processes. 

Nonwoven production methods are used to produce classic masks. Polypropylene fiber is used because of its nonabsotba prop rties for the basic medical madrs. Polypropylene fiba does not absorb the humidty. The surfiice of the fib collect die humidity and particules. Humidity transfer can not be prevented effectively. By using these masks for a long time viruses and particules pass fiom the filter and enter to bo. ... 

Another way of obtaining fibers from agricultural residues is pulping. However, using this method, the obtained fibers are 0.5 to 1.5 mm in length, which is too short to be processed in textiles, nonwoven production and some other industrial applications [7,12]. As known, aspect ratio is a major factor influencing the mechanical properties of a composite. Higher aspect ratio results in better tensile, flexural and impact... 

Watzl A. (1992), Recycling of Textile Waste into Nonwovens Products , Melliand Textilberichte, 397, 73. 

A possible source of infection to the patient is the pollutant particles dropped by the nursing staff, which carry bacteria. Single-use nonwoven products in the operating theatre have been adopted to prevent these sources of contamination of the patient. 

Nonwoven products are often composite materials combining the nonwoven with polyethylene film, for example. 

The USA has the highest penetration of single-use nonwoven products, at 80% of the market and will probably remain at that rate in the future. Due to higher performances, new technologies will probably replace older ones. These new technologies will become more cost-effective and, as in the case of the environment, will offer additional value to consumers. - ... 

EDANA(1996), The Complete Cover Story. Nonwovens Products intheO.R., Duesseldorf, Germany, Sommerfeld Ed. 

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