Nonwoven fabric is, as its name implies, a kind of fabric that is not woven. Nonwoven fabrics are made by putting randomly piled webs of filaments together in the form of a sheet through the means of gluing the filaments with an adhesive, entangling them by water jets or other type of pressure, or bonding them together by using the property of filament that becomes solid after being melt by heat. Nonwoven fabric is used in a vast variety of applications as its texture and strength can be adjusted flexibly by changing the raw material used, manufacturing method, sheet thickness, or density. Nonwovens come in handy in various aspects of our daily life across a wide range of fields from civil engineering and construction to agriculture, automobiles, clothing, cosmetics, and medicine.
Features of nonwoven fabric
Many different types of nonwoven fabric can be produced by selecting a different manufacturing method or raw material and designing a different thickness or density. Properties suitable for a specific use or purpose can also be added.
Unlike cloth made by weaving filaments in a matrix, nonwoven fabric, formed by putting randomly piled filaments together, has no vertical or horizontal directionality and is dimensionally stable. In addition, a cut portion does not fray.
Unlike traditional types of cloth and fabric, nonwoven fabric does not require a weaving or knitting process, thus allowing low-cost production and facilitating mass production.
Unitika's nonwoven fabrics
There are many methods of producing nonwoven fabric. At Unitika, the spunbond method and spunlace (water jet interlacing) method are mainly used. Here, the spunbond and spunlace methods are explained, along with the raw materials used for these methods.
This method first melts resin tips, which are the raw material, into filaments. Then, after the filaments are accumulated on a net to form webs, those webs are bonded in the form of a sheet.
The major conventional method of manufacturing nonwoven fabric involves two processes: (1) processing resin into filaments such as staple fibers and (2) processing them into nonwoven fabric. With the spunbond method, by contrast, all the processes from filament spinning to nonwoven fabric formation are performed at once, thus enabling speedy production. Made from non-fragmented long filaments, spunbond nonwoven fabric is very strong and dimensionally stable and can be used in a variety of applications.
Raw materials used for Unitika's spunbond nonwoven fabric
In addition to products made of polyester and polyester-polyethylene composite, we have been active in recent years in developing products that address increasingly challenging environmental issues, such as TERRAMAC, which is biodegradable plastic made from plant-derived polylactic acid, and Recycled Needle Punched MARIX made from recycled polyester.
This method sprays a high-pressure liquid stream onto deposited fibers (drylaid web) and entangles them together in the form of a sheet by using the water pressure.
Since a binder is not used, a cloth-like soft fabric that easily drapes can be manufactured. Not only products made of 100% cotton, which is natural material, but also laminated nonwoven fabric made from different types of nonwoven fabric material can be made without the use of a binder. These fabrics are also suitable for sensitive applications such as sanitary and cosmetic products.
Raw materials used for Unitika's spunlace nonwoven fabric
The main product is cotton spunlace nonwoven fabric made of only natural material of cotton. Other types of products also use environmentally-conscious clean materials, such as Lyocell, which is natural material made from eucalyptus, and TERRAMAC, which is biodegradable plastic made from plant-derived polylactic acid.