Generally speaking, nonwovens enterprises rely on highly engineered mass production. Due to competitive pressure, they constantly need innovation to ensure the production of high-quality products within specifications at the lowest cost. The technological development in the fields of machinery, process control and materials has promoted the development of the industry. In order to achieve sustainable development, nonwovens enterprises need to be at the forefront of these developments.
What is nonwoven?
Non woven fabrics are widely defined as web structures bonded together by mechanical winding fibers, hot-melt fibers or chemically bonded fibers. The definition of nonwovens is more accurately defined by different institutions, of which the most commonly cited is the definition of the International Nonwovens and Disposable Products Association (Inda): nonwovens are thin sheets, nets or rackets made of natural and / or man-made fibers or filaments (excluding paper), which have not been converted into yarn, and they are combined with each other in many ways.
Various methods of bonding are:
1. Add adhesive.
2. Hot melt the fibers with each other or with other fusible fibers or powders.
3. Melt the fiber by dissolving the fiber and then re solidifying its surface.
4. Form physical entanglement or cluster between fibers.
5. Stitch the fibers or filaments in place.
Nonwovens are not made by weaving or weaving, and there is no need to convert fibers into yarns. Nonwovens are engineering fabrics, which can be disposable or very durable. They are used in many applications, including:; Baby diapers, adult incontinence products, wet wipes, surgical curtains and covers, liquid filter elements and bag filters, masks, air conditioning filters, soil stabilizers and road cushions, erosion control, drainage systems, insulating materials (fiberglass cotton), pillows, cushions and upholstery cushions, carpet cushions, car roofs and interiors, house packaging and disposable clothing (foot covering, overalls).
Manufacturing technology of Nonwovens
The manufacturing of non-woven fabrics can be simply described as a series of manufacturing steps, including forming fiber webs, winding or bonding fiber webs to give structural mechanical integrity, and finishing / converting fabrics to give some special properties to the fabric specified by the customer. The manufacturing steps are as follows:
Network formation
The characteristics of the fiber web are the key determinants of the physical properties of the final product. The choice of the fiber web forming method depends on the fiber length. Initially, the short fiber web forming method is based on the textile carding process, while the short fiber web forming method is based on the wet laying process similar to papermaking. These technologies are still in use, but based on the extrusion machine (spinning laying) The method of forming a net directly from the filaments has also been developed.
The mechanical strength of the fiber web is very low and further manufacturing processes are required to form fabrics with useful properties. As described in the following section, there are many processes to achieve this.
network connections
Needling is a process of mechanically interlocking a nonwoven web structure with fibers through the web. Needles with thorns are installed on a plate, thread the fibers into the web, and then pull them out to wind the fibers together. The needles are separated in a non-aligned arrangement and are designed to release the optical fibers when the needle plate is pulled out.
Stitching bonding is the use of knitted elements (with or without yarn) A method of reinforcing fiber webs to interlock fibers. There are many different yarns that can be used. Furniture is the market for these fabrics. Other uses include vacuum bags, geotextiles, filters and linings. Sewn bonded fabrics are replacing woven fabrics in many applications because they produce faster and therefore greatly reduce production costs.
Thermal bonding is the process of using heat to bond or stabilize the web structure composed of thermoplastic fibers. All parts of the fibers act as thermal adhesives, so there is no need to use latex or resin adhesives. Thermal bonding is the main method used in the baby diaper covering industry. Polypropylene is the most suitable low melting point fiber, with a melting point of about 165C. It also feels soft The web passes between heated calendar rollers, where the fiber web is bonded. In most cases, point bonding using embossing rollers is the most ideal method to increase the softness and flexibility of the fabric. Bonding the entire surface of the fabric with a smooth reel increases the strength, but reduces the drapability and softness.
Chemical bonding is the process of chemically bonding paper web, which is one of the most commonly used bonding methods