Uneven thickness of non-woven fabrics under the same processing conditions may have the following reasons:
(I) Low-melting fibers and conventional fibers are not uniformly mixed with cotton: different fibers have different cohesion. Generally speaking, low-melting fibers have greater cohesion than conventional fibers and are less likely to disperse. For example, Japan 4080, South Korea 4080, South Asia 4080 or Far East 4080 have different cohesive forces. If the low melting point fiber is unevenly dispersed, the low melting point fiber content is less, because it cannot form a sufficient network structure, and the nonwoven fabric is thin Relative to the low-melting point fiber content is thicker.
(2) Incomplete melting of low melting point fibers: Incomplete melting of low melting point fibers is mainly due to insufficient temperature. For non-woven fabrics with low basis weight, it is not easy to cause insufficient temperature problems, but for high basis weight, high The thickness of the product requires special attention. Non-woven fabrics located at the edges are usually thick because of sufficient heat, and non-woven fabrics located at the middle part, because the heat is not enough to form a thin non-woven fabric.
(3) High shrinkage rate of fiber: Whether it is a conventional fiber or a 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 shrinkage during the production of non-woven fabric.
The problem of static electricity during the production of non-woven fabrics is mainly caused by the low moisture content in the air when the fibers contact the card clothing, which can be divided into the following points:
(1) The weather is too dry and the humidity is not enough.
(2) When there is no oil on the fiber, there is no antistatic agent on the fiber. Because polyester cotton has a moisture regain of 0.3%, the absence of antistatic agents results in static electricity during production.
(3) The fiber oil content is relatively low, and the relative content of static electricity agent will also generate static electricity.
(IV) SILICONE Polyester Cotton Because of the special molecular structure of the oil agent, the oil agent contains almost no water, and it is relatively easy to generate static electricity during production. Generally, the smoothness of the feel is proportional to static electricity. Big.
(5) In addition to the method of preventing static electricity from humidifying the production room, it is also an important task to effectively eliminate oil-free cotton during the cotton feeding stage.
Under the same processing conditions, the causes of uneven soft and hard fabrics are generally similar to the causes of uneven thickness. The main reasons may be the following:
一 (1) The cotton blended with low melting point fiber and conventional fiber is not uniform, the part with higher low melting point content is harder, and the part with lower content is softer.
二 (2) Incomplete melting of low-melting point fiber causes softness of non-woven fabric
(3) The high shrinkage of the fiber will also cause the problem of uneven soft and hard nonwoven fabrics.