Under the same processing conditions, the thickness of the non-woven fabric produced is uneven:
(1) Non-uniformity of low-melting fiber and conventional fiber blending: Different fibers have different cohesion. Generally speaking, low-melting fibers have greater cohesion than conventional fibers, and are less likely to be dispersed. The portion where the fiber is unevenly dispersed and the content of the low-melting fiber is small, because a sufficient network structure cannot be formed, the nonwoven fabric is thin, and a relatively thick phenomenon is formed in a place where the content of the low-melting fiber is large.
(2) Incomplete melting of low-melting fiber: Incomplete melting of low-melting fiber, the main reason is that the temperature is not enough. For non-woven fabrics with low basis weight, it is usually not easy to produce insufficient temperature, but for high basis weight, high Thickness products require special attention. The non-woven fabric at the edge has a thick heat, and the non-woven fabric is usually thick. The non-woven fabric is located in the middle portion because the heat is less likely to form a thinner non-woven fabric.
(3) High shrinkage of fiber: Whether it is conventional fiber or low-melting fiber, if the hot air shrinkage rate of the fiber is high, the problem of uneven thickness is likely to occur due to the shrinkage problem during the production of the nonwoven fabric.
The main reasons for the unevenness of soft and hard may be the following:
(1) The low-melting fiber and the conventional fiber are unevenly mixed, the part with a higher low melting point content is harder, and the lower part is softer.
(2) The melting of the low melting point fiber is not complete, resulting in a softer nonwoven fabric
(3) The high shrinkage rate of the fiber also causes the problem of uneven softness and hardness of the nonwoven fabric.
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