Author：Baby & Adult Diaper Materials FROM：Diaper Materials Manufacturer TIME：2023-02-15
In recent years, the production technology of spunbond non woven fabric in my country has been perfected, and the actual production efficiency has become higher and higher, which has been recognized by many enterprises and researchers, but the problem of merging the production line has not been solved. Based on previous work experience, this paper summarizes the main reasons for doubling of spunbond non woven production lines.
From the point of view of practical work, the size of the mainstream outflow cross section slit in the nozzle of the spunbond non woven fabric production line is the key content, and the actual requirements are also very strict. However, it can be seen from the actual processing that it is difficult to maintain high precision in the 600mm length range. This type of accuracy is in a state of change within a certain range, such as unequal air flow, inconsistent flow velocity, etc., which may cause problems with wire merging. In addition, when the nozzle is in use, due to the obvious leakage and wire breakage of the upper spinneret, it is easy to cause the molten mass to enter the nozzle, which increases the probability of transverse airflow problems. In addition, when the tunnel is dredged, the staff will choose metal hooks to perform the operation, which is easy to cause the deformation of the upper lip of the throat, which also makes the control of the overall dimensional accuracy more difficult, and increases the probability of the occurrence of the problem of splicing. When the spinneret is cleaned, the staff often chooses to spray silicone oil on the spinneret. If the spray is excessive, the silicone oil will also enter the tunnel, causing a large number of fibers to stick to the inner wall and increase its roughness, which will also cause and wire problem.
When the two rollers move in one direction, the streamline will be significantly compressed and become more and more dense, which also makes the air flow faster and faster, causing the fibers to move closer to it. Affected by this, the filaments will also swing , under normal circumstances, the direction of movement of the bundled wire and the swing roller is in the opposite state. From a theoretical point of view, the filaments of different stations can fall parallel to the mesh curtain, but this is not the case. This is mainly due to the fact that it is impossible for the filament to fall exactly in the middle of the distance c. Even if it can be done in a static state, the subsequent action will change. At this time, the drafting airflow faced by the entire system is turbulent, which makes the airflow around the round rollers. It gets very messy, and eventually two things happen: first, the two strands will cross each other; second, one of the strands will be on the left and the other on the right. From the nozzle outlet of the spunbond non woven fabric production line to the screen curtain of the web forming machine, the bundled filaments are very easy to become double filaments.
Generally speaking, there are three main ways of doubling in the net curtain of the net former. The first is the doubling formed on the net curtain, which is similar to the cat's tail and can roll on the net curtain. Secondly, in the net curtain at the rear of the net forming machine, there will be a flake surface turning net layer. Finally, the surface layers of the flocks on both sides of the mesh curtain at the rear of the web forming machine are in the state of flanging. Strictly speaking, the latter two cases do not belong to the problem of doubling, but the final effect is the same as that of doubling, which will affect the surface quality of the non woven fabric. The reason why there is a problem of bundling of the net curtain of the net forming machine is mainly due to the unbalanced air flow between the upper and lower air flow of the net curtain of the net forming machine. The main source of drafting power for spunbond non woven fabric is air. In the subsequent operation process, the flow injected into the nozzle will be ejected from the nozzle outlet and transferred to the screen curtain of the screen machine. After the curtain suction channel, the air conditioner fan pressurizes it and then discharges it. At this time, the amount of air sprayed to the mesh curtain is huge, but the air intake in the air conditioning room is limited, and the remaining air will flow forward and backward along the surface of the mesh curtain. It is dominated by cat tail like strands, which eventually lead to the problem of filamentation.
All in all, it can be seen from the actual production of spunbond non woven fabric production line that the probability of yarn doubling problem is high, especially when the air volume of the nozzle is increased to the screen curtain, the air intake in the air conditioning room is small, which eventually leads to the occurrence of contamination in the production line. wire problem. Understanding the specific reasons for doubling in spunbond non woven fabric production lines can help solve this problem.
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