Views: 268 Author: Site Editor Publish Time: 2021-07-02 Origin: Site
Non-woven fabric refers to an ordered or disordered fiber non-woven sheet obtained by arranging or spraying spun-shaped fibers on a substrate. Non-woven fabrics have the advantages of low cost and wide applications. With different processing technologies, we can make different products, such as polypropylene fabric bags, non-woven fabric biodegradable, non-woven biodegradable fabric, etc. There major processing technologies are as follows.
Spinning fusion is the most widely used one-step spinning process for forming non-woven fabrics. By way of using this technology, we can produce many products. For instance, non-woven handle bag, polypropylene grocery bag, non-woven recycle bag, etc. are very popular. Spunbonded nonwovens are formed with continuous filament fiber, which has high production speed, high product strength and good dimensional stability, but low fluffy, poor uniformity and surface coverage.
The spun bonding method combines fiber spinning technology and non-woven forming technology, using the principle of melt spinning. The raw materials are melted and mixed by the extruder, and then extruded by the spinneret of the spinning head to form a trickle of melt. High-speed quenching air is used to cool the extruded melt stream, and the fiber is stretched by the stretching airflow during the cooling process to form a continuous filament with higher strength and more stable performance. After the filaments are divided to form a uniformly distributed monofilament structure, they are laid on a net curtain with negative pressure to form a non-woven web. After the fiber web passes through the subsequent reinforcement device, hot-rolled reinforcement, needle punch reinforcement or spun lace plus fixed type, the product is wound by the coiling device. The key steps are melted spinning, air drawing of nascent fibers, fiber web formation and fiber web setting
Melt-blowing is to spray the melt extruded by the screw with a high-speed and high-temperature airflow, so that the thin stream of the melt is stretched at a higher rate to form ultra-fine short fibers, and then piled on the condensation screen or into the net drum. A continuous short fiber net is formed, and then the non-woven fabric is made by self-adhesive or other reinforcement processes.
The processing of melt blown non-woven fabric bags also use the melt spinning method. However, the difference from the spun bond method is that the spinneret head used in the melt blown method has specially designed air ducts on both sides of the spinneret hole. The heated high-pressure air is blown out of the air duct to affect the melt. The thin stream is stretched at a high speed to be blown into ultra-fine short fibers. After the ultra-fine short fibers are cooled by the cold air blowing under the spinneret, they are sprayed at a very high rate to a fiber collection device with negative pressure, mainly a net curtain or a web forming drum, to form a fiber web. Finally, the molded non-woven fabric is obtained by adding a fixed type through methods such as self-adhesive or thermal bonding.
This method can be made into a thin sheet or a thicker felt-like material. Melt blown non-woven fabrics are formed from ultra-short fine fibers, with low production line speed and short process flow, but are more complicated. Melt blown non-woven products have large specific surface, high bulkiness, low transition resistance, high filtration efficiency, good surface coverage and shielding performance, but low strength, poor dimensional stability, poor wear resistance, and large air consumption during processing and high energy consumption. Although the production process of melt blown non-woven fabrics is shorter than that of spun bond, the process is more complicated and has many influencing factors.
