Tianfang non-woven fabric refers to a type of ordered or disordered fiber non-woven sheet material obtained by arranging or spraying spun fibers onto the substrate, and curing them in different forms. The non-woven fabric has the advantages of low cost and wide use
1.Spinning adhesive method
Spinning method spin nimg fson is the most widely used one-step spinning and forming process. Non woven fabrics adopt continuous filament fiber shape, with high production speed, high product strength, and good dimensional stability. However, the uniformity and surface quality of the mesh are slightly poor due to low crown.
The spinning method combines fiber spinning technology with non-woven forming technology, utilizing the principle of bulk spinning. After the raw materials are 2blended and blended on the machine, they are controlled by the quality silk plate at the spinning machine head to form a path flow. High reading alarm air and stop flow cooling are used to cool the fibers, while the fibers are subjected to the pulling effect of electricity and flow in the process of combining, forming a continuous long line with high scheduling and physical capacity. After the long line is divided into different sections, a distributed single inquiry is formed, The negative and joyful net is formed in weaving red, and the net after warp is like a knot. After implementing Beigu, needle reinforcement, or water pricking with fixed type, the product is obtained by winding through the winding device. The key steps are melt spinning, primary fiber airflow stretching, fiber web formation, and fiber web shaping.
(1) Melt spinning
The raw materials need to be pre dried to avoid peak decomposition during high temperature heating, especially to prevent moisture from vaporizing and forming bubble filaments at high temperatures, which can cause hairiness or breakage, affecting production quality and normal production. The control of spinning process mainly involves controlling the spinning temperature in the following aspects: mainly controlling the temperature of spinning components such as the quality silk board. The appropriate spinning temperature should ensure sufficient fluidity of the object, ensure the smoothness of the quality silk, and ensure high uniformity and spinnability of the body, so that the subsequent airflow stretching process can be carried out efficiently and with high fiber orientation. The spinning temperature should be controlled between the melting point and decomposition temperature. Increasing the spinning temperature appropriately can improve the fluidity of the melt
Control of spinning end pressure: mainly to control the pressure of the yarn in the spinning pin body. If the roller force is too low, the yarn flow is unevenly distributed on the spinneret plate, and the fine flow of the yarn is unevenly distributed. If the friction force is high, it is easy to cause room efficiency not to be controlled by the spinning speed according to the friction force. The spinning speed affects the size and uniformity of the fiber density, as well as the quality of non-woven fabrics. The spinning speed is too low, The rapid cooling of the extrusion volume flow leads to easy wire breakage during stretching, while the anti wire speed is too high and the path flow cannot be cooled in a timely manner, resulting in wire merging and affecting the quality of non-woven fabrics.
(2)Airflow stretching of primary fibers
In order to improve the performance of non-woven fabrics, black also needs to pull and orient the cut fibers to improve the orientation and crystallinity of the fibers. In order to improve the physical and mechanical properties of the fibers, it is high in the production of non-woven fabrics in Hefa. Due to the high-speed connection of subsequent processes such as spinning, drawing and splitting, air laying, and processing. The stretching of fibers is completed in a very short period of time, and ideal cooling effect is also required for the fibers. Therefore, the production of spunbond injection North woven fabric is based on the principle of the multi flat field and flow stretch air flow stretching process: the silk strip is made of high-quality silk holes, and after 0 times of air cooling, it is directly sucked into the suction port of the air flow stretching machine that is not prepared. In the flow duct of the Labo equipment, the stretching airflow is blown in by the fiber direction sensor, and the fibers rapidly accelerate under the support of high-speed and high-pressure stretching airflow, and stretch through the stretching nozzle. Airflow stretching equipment mainly includes tube type drawing machines, narrow slit drawing machines, and wide slit drawing machines.
The control of the airflow stretching process is mainly achieved through the traction structure. In the case of constant air flow, the smaller the stretching mouth and air duct, the higher the stretching speed, and the higher the fiber strength. The wind mixing of the first stretching wind, the wind speed and cooling conditions of the whole stretching wind, are also included.
The process of forming a network by spinning the meridians and pulling them into a plow by airflow, and then dividing the continuous length of the plow into strands to disperse the individual strands, and laying them on top of the wind tunnel. For the surface method of non woven fabric production, due to the use of continuous long ground production. The separation and bonding process have short intervals, and the disturbance of high-speed stretching airflow is severe, making it difficult to control the movement of fiber filaments and affecting the uniformity of fiber web formation. Therefore, the unified bonding method cannot form hidden non-woven fabrics
Hongwei's web process first requires the separation of long fibers drawn by airflow. The purpose is to separate the fibers into high single hate long fibers to prevent them from connecting during web laying and affecting the uniformity of the web. The main methods of separation include electrostatic separation, machine reduction separation, airflow separation, etc. After the separation process, the fiber long fibers are evenly placed on the web using different techniques to form a non-woven web, The process of laying the mesh involves controlling the movement of the fiber filament according to the set edge to ensure a stable and uniform shape of the mesh. The control of the fiber movement is also achieved through the use of mechanical wooden airflow. Therefore, the main methods of laying the mesh include stroke laying, scattered laying, degree laying, and flow channel laying. In the process of precision mesh, in order to quickly determine the knots of the red mesh and avoid external factors, the method of negative pressure net is used, In the space below the mesh curtain, vacuum suction is used to create negative pressure on the surface of the mesh curtain, thereby collecting and regulating the fiber filament. The negative pressure mesh laying method has a certain pulling effect on the fiber, and on the other hand, it can eliminate the high-speed air flow produced by the front pipe conveyor, which prevents the wind from blowing in the mountains. Therefore, in the process of mesh laying, the requirements for Weifeng South are high, The laying of the mesh requires good breathability, high tensile strength, sufficient mesh strength, good electricity, and a close arrangement of the mesh to meet the requirements of transporting the fiber mesh and separating the airflow on both legs.
(4) Fiber mesh shaping
The non woven fibers formed by the process of splitting and laying mesh are only simple physical knots between the fiber filaments, and the knots are not yet firm. Therefore, it is necessary to undergo addition and shaping treatment in order to ultimately produce high density and stretchable non-woven fabrics. The reinforcement and shaping methods include heat judgment addition method, needle making addition method, and water pricking reinforcement method.
My car's addition and setting method: mainly applicable to the gradual mesh of thermoplastic polymer materials such as P, the principle is to increase the heat of polymer fibers in the actuator and synthesize them at the actuator/surface under pressure, significantly improving the strength of the fibers and achieving the addition and setting of non-woven fabrics. The heating force is composed of heated rigid silver and elastic rollers, which can have point bonding and surface bonding methods. During point bonding, patterned rollers with different rolling point shapes are used, Polished rigid brocade is used for surface bonding.
The Linggu method uses a system with a triangular surface or its ground, and an inverted edge to repeatedly puncture the fiber mesh. The remaining fibers are pierced through the middle, and the surface layer of the final mesh is strongly carried out inside the outer mesh to form a knot, which is no longer repeated. Under the friction of the final dimension, the mesh is pressurized by 8 liters of liquid pressure, and after multiple iterations of learning, numerous dots are formed. Finally, the good mesh drawing is determined, and the needle/method is mainly used to add traditional Chinese art The movement direction of the needle system, such as the main flower dual duty machine ring system and the good system, is usually perpendicular to the red net, but there are also upward or downward sounds
2.Melt blown method
The volume spraying method meh-0wing is to blow the extruded body with high-speed and high-temperature airflow, causing the body flow to be pulled at a high rate to form ultra short fibers. Then, it is stacked and woven onto a condensed mesh or a web roller to form a continuous fiber network, and then produced into a non-woven fabric through self adhesive or other processing.
The processing of non-woven fabrics using the melt spinning method also adopts the melt spinning method, which extrudes the melt fine flow to form fibers through the spinneret hole. However, unlike the spunbond method, the spinneret head used in the spray method has a specially designed air duct (air) on both sides of the spinneret hole. The heated high-pressure air is blown out of the air duct to stretch the melt fine flow at high speed, thereby blowing it into ultrafine short fibers, After being cooled by a cold blowing air below the spinneret head, ultra-fine short fibers are sprayed at a high rate into a fiber collection device with negative pressure, mainly through a condensing mesh curtain or a mesh forming roller, forming a fiber mesh. Finally, the formed non-woven fabric is obtained by adding a fixed type through self adhesive or thermal bonding methods.
This method can be used to make thin sheets or thicker felt like materials. Melt blown non-woven fabric is formed using ultra-short fine fibers, with low production line speed and short process flow, but it is more complex. Melt blown non-woven fabric products have larger surface area, higher fluffiness, lower transition resistance, higher filtration efficiency, good surface coverage and shielding performance, but lower strength, poor dimensional stability, poor wear resistance, high gas consumption during processing, and high energy consumption. Although the production process of melt blown non-woven fabric is shorter than that of spunbond method, its process is more complex and has many influencing factors:
1. Melt spinning
During the process of melt spinning, the spinning fibers are woven with high pulling speed, which requires high requirements for the object of extruded quality silk. In order to meet the higher requirements of product quality, it is required to control the pressure, maintain a uniform flow of the melt, and ensure that the raw material is completely plastic. In order to prevent excessive impurities in the melt from blocking the spinneret and affecting the continuity of the spinneret, the melt needs to pass through a filtering device before entering the melt blown mold head
2. Jet stretching
During the production process, heated Gaole air is blown out at a high speed in the drawing duct, and high-speed drawing is carried out on the body thin flow extruded from the quality wire hole to produce short fibers with fine process. Therefore, the speed and temperature of the drawing air flow have a significant impact on the formation and drawing of short fibers. The higher the airflow speed, the finer the diameter of the short fibers sprayed, but a high flow rate can affect the collection of fibers. The temperature of stretching hot air should not be too low, and it should be able to keep the melt in a viscous state,
3. Fiber mesh forming
After being cooled by wind, the ultra-fine short outer dimension obtained by hot air spraying and pulling electricity is directly sucked into the lower part of the lake mesh or the inner part of the porous filter. The fibers are collected on the road curtain or porous filter, and are mainly of the self enjoying surface thermal adhesive type. The vertical distance from the outlet of the waste wire hole in the machine head to the surface of the suspect mesh or porous filter is called the receiving distance of the fiber mesh, The distance between fiber mesh connections has a significant impact on the breathability, strength, and other properties of nonwoven products, as well as the stretching ratio of short fibers and the precision range of fibers. The higher the receiving distance of the fiber mesh, the longer the time it takes for the sprayed short fibers to reach the collection gauge, the less fibers collected at the same location, and the more flustered the outer mesh. As a result, the pore diameter and porosity of the nonwoven fabric increase, the air permeability improves, and the deformation effect improves. Although the hand is fluffy, the tensile strength and top strength of the nonwoven fabric both decrease, and the contact distance decreases. The cooling effect of the warp and warp is poor, and the warp and warp are easy to blend, And it becomes a clustered state in the alley, resulting in a low degree peak of the fiber mesh canopy, a shadow hall where the receiving distance from the outside and the root are compared to the sub network. If a continuous process of changing the receiving distance is used during the fiber mesh forming process, non-woven fabrics with density gradients can be produced, and filter core materials can be used for graded filtration.
In order to overcome the shortcomings of low strength and poor dimensional stability of tumor based nonwoven fabrics, the production process of composite nonwoven fabrics composed of two or more environmental machines and adhesive machines was first developed by the American company KMBERLEY,/sea spray composite method SMESMS),
The principle of SMS composite method is to form a composite production line between two spinning non-woven fabric forming machines, such as a melt method non-woven fabric forming machine, to produce non-woven fabrics with spinning red mesh and sea court fiber mesh. This process combines the advantages of high strength of filament warp and dimensional outer mesh, good size and fixed parts, as well as the advantages of high fluffiness and good breathability of relatively fine short fiber mesh, to composite non-woven fabrics with excellent comprehensive performance, And it has been widely used in surgical gowns, filtering materials, and other aspects.
In the SMS composite production process, on the same production line, there are two spinning heads and one quality head at the same time. The first material head produces long fibers to form the first layer of fiber network, which is a continuous long dimensional fiber network mainly provided for composite nonwoven fabrics; By controlling the amount of fiber mesh, the degree, softness, and feel of the composite nonwoven fabric can be adjusted. Then, a second layer of mesh is formed on top of it through a quality mold, forming a high-quality ultra-fine dimensional mesh. The quality output can be controlled, and the breathability and filtration performance of the composite nonwoven fabric can be controlled. The three layers of fiber mesh are bonded or self-adhesive to synthesize SMS nonwoven fabric through a sheep press. Due to the low efficiency of melt blown production, to ensure product quality and performance, it is necessary to maintain the spinning and bonding speed. Increasing the number of melt blown mold heads can improve productivity.