Nonwoven fabric
Nonwoven
fabric is a fabric component that is produced from staple and long fibers,
bound together by chemical, mechanical, thermal, or solvent treatment. Used to
denote what is not woven or woven as felt in the textile manufacturing
industry. Some molecules of woven material lack sufficient strength unless
solidified or strengthened by support. In recent years, nonwovens have been used
instead of polyurethane foam.
History
In the nineteenth century, when England was a leading country in textile
production, a textile engineer named Garnett realized that a large amount of
fiber was wasted as a trim, so he developed a special carding device to
distribute this waste material in fibrous form. This fiber was used as a
filling material for pillows. Although the Garnett machine has changed greatly,
it still retains its name and is a major component of the nonwoven industry.
Later, manufacturers in northern England began tying these fibers mechanically
and chemically to batts. These were the precursors of today's nonwovens. An
exploration of the nonwoven fabric industry began in the late 1940s,
which entered a commercial phase in the 1950s and then expanded commercially in
the 1960s.
Properties of nonwoven fabric
1.
Non-woven fabrics can look like paper, felt, or woven fabrics.
2.
Its hand-feel may be soft, elastic, or maybe hard, stiff, or slightly elastic.
3.
It can be as thin or many times thick as tissue paper.
4.
It can be transparent or opaque.
5.
It can be a low tear and blast energy to very high tensile strength.
6.
It can be fabricated by gluing, heat bonding, or sewing.
7.
The drapability of this type of fabric is not much different from good.
8.
Some fabrics have excellent laundry; Nothing else.
9.
Some may be dry-cleaned possible.
10.
It provides specific works such as absorbency, strength, flame retardancy,
washability, cushion, fluid repellent, elasticity, stretch, softness, thermal
insulation, acoustic insulation, filtration, bacterial barrier, and germs.
Types of nonwoven fabric
The
main and most common types of non-woven fabrics are:
1.
Spun-bound/Spun-lace.
2.
Air-laid.
3.
Dry-laid.
4.
Wet-laid.
Spun-bound: Span-bound fabrics are produced by
binding fibers in an album method by depositing extruded, spun filaments in the
collection belt. The fibers are separated at the time of laying process on the
web by air jets or electrostatic charges. Spun-bound
products are used in carpet backing, geotextile, disposable medical /
hygiene products, automotive products, civil engineering, and packaging
products.
Air-laid: Air-laid fabric is mainly made with
wood pulp and has good absorption nature. It can be mixed with a certain
proportion of sap to improve its wet absorption capacity. Air-laid nonwoven dry
paper is also referred to as nonwoven. Nonwoven is made through the process of
an air bed. Transfer the wood pulp to an airflow bundle to spread and
consolidate the fibers on the floating web. The Air-laid non-woven bonnet is
reinforced on the web.
Dry-laid: Dry laid webs are simply produced using
staple fibers natural or manmade. Dry laid webs making process consists of 4
steps:
Staple
fiber preparation –> Opening, cleaning, mixing & blending –> Carding
–> Web laying.
Wet-laid: wet-laid non-woven fabric is made by a
modified papermaking process. That is, the fibers used are suspended in water.
One of the main goals of wet-laid nonwoven manufacturing is to produce
textile-fabric characteristic structures, primarily flexibility and strength,
at the speed of those involved in making paper. Special paper machines are used
to make uniform sheets of material to separate water from the fibers, which are
then bonded and dried. In the roll, good industrial 5-10% nonwovens are made
using wet-leveled technology.
The non-woven fabric production process
Nonwoven
fabric production can be described in simple terms as a series of integrated
production steps to wrap or bind the fibers on the web to maintain mechanical
integrity in the structure and to give the fabric some special features.
1. Web formation
The
properties of the fibrous web are the key determinants of the physical
properties of the final product. The choice of method for forming webs is
determined by the length of the fiber. Primarily, the methods of forming mesh
from main length fibers were based on the textile carding process, whereas web
formation from short fibers was based on wetting the same kind of paper. These
technologies are still in use, but immediately Methods based on web structure
have also been developed. Fiber webs have little mechanical strength and
require a further manufacturing process to form a fabric with useful
properties. There are many processes that are used to perform this as described
in the next section.
2. Web bonding
Needle
punching is the process of bonding a nonwoven web structure that mechanically
connects fibers to the web. The cut needles, attached to a board, are retracted
by punching the fibers to the web and then the fibers. Since the needle board
is retractable, the needles are emptied in a non-aligned format.
i. Stitch bonding: Stitch bonding is a method of assembling
fiber gels with yarn components with or without yarn to attach the fibers.
Different types of yarn can be used. Upholstery is a market for these fabrics.
Other uses are vacuum bags, geotextiles, filtration, and interconnections. In many
applications, sewing-tied fabrics are replacing woven products because they are
faster to produce and therefore, the production cost is significantly lower.
ii. Thermal bonding: The process of stabilizing a web
structure with thermal bonding heaters or thermoplastic fibers. All parts of
the fibers act as heat binders, thus eliminating the use of latex or resin
binders. Thermal bonding is a major method used by the cover stock industry for
baby diapers. Polypropylene has become the most suitable fiber with a low
melting point of about 165C. It is also soft to the touch. The fiber web is
passed between the heated calender rollers, where the web is closed. In most
cases point binding using embossed rolls is the most preferred method, adding
softness and flexibility to the fabric. The use of smooth rolls increases
strength by binding the entire surface of the fabric but reduces grooves and
softness.
iii. Chemical bonding: Chemical bonding the process of web
bonding and bonding through a chemical is one of the most common methods.
Chemical binders are applied to the web and cured. The most used binder is
latex because it is economical, easy to apply, and very effective. Different
techniques are used to apply the binder and include saturation bonding, spray
bonding, print bonding, and foam bonding.
iv. Hydro entanglement: Hydro entanglement is the process of
using liquid energy to lock fibers together. This is achieved by fine water
jets operated through the web, supported by a conductive belt. The water gets
entangled when the web is attacked and the fibers are removed. Strong movement
fibers get involved in the web.
3. Finishing and
converting
Finished
and converted the last operation performed on the fabric before being delivered
to the customer. Finishes include some activities like coating and laminating
to change the wet properties of the fabric, coronation and plasma treatment,
wet chemical treatment to provide anti-static properties, anti-microbial
properties, flame retardant, etc. This is usually cut to width specifying a
rebound ready for customer shipment this is known as conversion.
Uses of nonwoven
1.
Nonwoven fabric is used in medical products like isolation gowns, surgical
gowns, masks, scrub suits, caps, gloves, plasters, etc.
2.
It is used as a filter for gasoline, oil, air, water, coffee, tea bags, the pharmaceutical industry, mineral processing, liquid cartridge, bag filters,
vacuum bags, etc.
3.
Its geotextile containers are used for soil stabilizers and roadway
underlayment, foundation stabilizers, erosion control, canals construction,
drainage systems, geomembrane protection, frost protection, pond, and canal
water barriers, sand infiltration barrier for drainage tile, landfill liners,
etc.
4.
It is used in making diaper stock, feminine hygiene, and other absorbent materials.
5.
It is used in carpet backing and primary and secondary composites.
6.
It is also used in marine sail laminates, table cover laminates, chopped strand
mats, shopping bags, acoustic insulation for appliances, automotive components,
and wall paneling.
7.
It is used in household products like pillows, cushions, mattress cores, upholstery padding, batting in quilts or comforters, etc.
0 Comments