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Problems encountered in the production process of non-woven fabrics and solutions

1. Polyester cotton abnormal fiber types


Answer: During the production of polyester wool, some abnormal fibers are inevitable due to the problems of pre-spinning or post-spinning conditions. Especially the recycled cotton produced by recycled slicing is more likely to produce abnormal fibers. The abnormal fiber outsole can be divided into the following types. ;


(1) Single root: fibers that are incompletely extended. Such fibers are prone to cause abnormal dyeing and have less effect on non-woven fabrics, but for water-needle fabrics or needle-punched fabrics for artificial leather fabrics. Has a serious impact.


(2) merging: After stretching, there are two or three fibers sticking together. This kind of fiber is easy to cause abnormal dyeing, and has less influence on non-woven fabrics, but for water needles used in artificial leather fabrics. Cloth or needle cloth has a serious impact.


(3) Colloidal shape: Broken or entangled filaments are generated during the extension, so that the fibers are not extended at all to form a hard cotton. The product can be further divided into a first-grade gel, a second gel, and a third-grade gel. Such abnormal fibers are often deposited on the card clothing after the carding process, causing problems such as poor formation of the cotton mesh or broken mesh. Such raw materials may cause serious quality defects for most of the non-woven fabrics.


(4) Oil-free cotton: During the extension period, there is no oil on the fiber during the unsatisfactory driving condition. This fiber usually has a dry feel. In addition to causing static electricity generated in the non-woven fabric production process, it also causes the semi-finished product to be finished. problem.


(5) The above four kinds of abnormal fibers, single root coarse and parallel yarn are more difficult to be removed during the production of non-woven fabrics. Colloidal and non-oily cotton can be removed as long as the production personnel pays little attention to reduce the defects of product quality.


Second, the reasons affecting the flame retardancy of non-woven fabrics


Answer: The reasons for the non-flammable effect of polyester wool are as follows:


(1) Conventional polyester cotton has an oxygen-limited index of 20-22 (the oxygen concentration in the air is 21%), which is a kind of combustible fiber, which is easy to ignite but has a slow burning speed.


(2) If the polyester chips are modified and denatured, they have a flame retardant effect. Long-lasting flame-retardant fibers mostly use denatured polyester chips to produce flame-retardant polyester wool. The main modifier is a phosphorus series compound. Phosphorus is combined with high-temperature heat and oxygen in the air to reduce the oxygen content. Flame retardant effect.


(3) Another method for making polyester wool flame retardant is the surface treatment method, which considers that the treatment agent reduces the flame retardant effect after repeated processing.


(4) Polyester cotton has the characteristics of shrinking when it encounters high heat. When the fiber encounters the flame, it is not easy to ignite due to shrinkage and is separated from the flame, resulting in appropriate flame retardant effect.


(5) The polyester wool has molten sag when it encounters high heat, and the molten drip phenomenon produced by the cotton wool after ignition can also take away part of it.


Heat and flame produce a suitable flame retardant effect.


(6) If the fiber is stained with easily flammable grease or silicone oil that can be used to shape the polyester cotton, the polyester wool will reduce the flame retardant effect. In particular, when a polyester wool containing SILICONE oil is exposed to a flame, the fiber cannot be shrunk and burned.


(7) To increase the flame retardant effect of polyester cotton, in addition to the use of flame-retardant denatured polyester chips to produce polyester wool, the use of a higher phosphate component on the fiber surface for post-treatment can also increase the flame retardant effect of the fiber. . Phosphorus molecules that are exposed to high heat in phosphates combine with oxygen molecules in the air to reduce the oxygen content in the air, thereby increasing the flame retardant properties.




The most suitable processing temperature for the three low melting point fibers


A: The melting point of the existing low melting point fiber is advertised at 110 ° C, but this temperature is only the softening temperature of the low melting point fiber. Whether it is Japan 4080, Korea 4080, South Asia 4080, or Far East 4080, it takes about 150 ° C to completely melt. Therefore, the most suitable processing and setting temperature should be the minimum requirement of 150 ° C x 3 minutes for the lowest temperature portion of the nonwoven fabric during heating.


Fourth, the cause of static electricity during the production of non-woven fabrics


Answer: The problem of static electricity generated during the production of non-woven fabrics is mainly caused by the low moisture content in the air when the fibers are in contact with the clothing. It can be divided into the following points:


(1) The weather is too dry and the humidity is not enough.


(b) When there is no oil on the fiber, there is no antistatic agent on the fiber. Since the moisture regain of the polyester cotton is 0.3%, the lack of an antistatic agent results in generation of static electricity during production.


(3) The fiber oil is low, and the relative electrostatic agent content will also generate static electricity.


(4) SILICONE polyester cotton has a special molecular structure of oil, and the oil agent contains almost no moisture. It is relatively easy to generate static electricity during production. Usually, the slip of the hand feels positively proportional to the static electricity, and the smoother SILICONE cotton is more static. Big.


(V) Methods to prevent static electricity In addition to humidification in the production work room, it is also an important task to effectively eliminate oil-free cotton during the feeding stage.


5. Why are the non-woven fabrics produced under the same processing conditions uneven?


Answer: The reasons for the uneven thickness of the nonwoven fabric under the same processing conditions may be as follows:


(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. For example, Japan 4080, South Korea 4080, South Asia's 4080 or Far East's 4080 have different cohesion. If the low-melting fiber is unevenly dispersed, the low-melting fiber content is less, because the mesh structure cannot be formed, and the non-woven fabric is thin. Relatively, a thicker 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 in the middle portion is less likely to form a thinner non-woven fabric because of the heat.


(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 shrinkage during the production of the nonwoven fabric.


6. Why are the non-woven fabrics produced under the same processing conditions soft and hard?


Answer: The reason for the uneven hardness of the non-woven fabric under the same processing conditions is generally similar to the reason for the formation of uneven thickness. The main reasons may be the following:


(1) The low-melting fiber and the conventional fiber are unevenly mixed, the part with a higher low-melting 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.


Seven: thinner non-woven fabrics are more prone to short code reasons


Answer: When the non-woven fabric is taken up, the speed of the finished product will become larger and larger. At the same winding speed, the linear speed will become larger and larger. The thin non-woven fabric will easily be stretched due to the small tension. Short-code problems occur after the roll is released due to tension. As for the thicker and medium-sized products, the production of tensile strength is larger, resulting in less stretching, and it is not easy to cause short-code problems.


Eight reasons why hard cotton is produced after the work roll is wrapped with cotton


Answer: The work roll is entangled during production. Most of the reason is that the oil on the fiber is low, causing the friction coefficient between the fiber and the clothing to be abnormal. The fiber sinks under the clothing and the work roll is entangled. The fiber wrapped around the work roll Can not be moved, gradually melted into hard cotton after constant friction between the clothing and the clothing. To eliminate the entanglement, the winding of the entanglement on the roller can be eliminated by lowering the work roll. In addition, it is easy to form a work roll lingering problem in case of long sleep.

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