( The main factors that influence the spun-bonded non-woven fabric physical properties analysis]

In the process of spun-bonded non-woven fabric production, various factors may affect the physical properties of the product. Analysis of the relationship between these factors and spun-bonded non-woven fabric properties, helps to control process conditions correctly, have good quality and wide applicability of spun-bonded non-woven products. At this point, in view of the spun-bonded non-woven main factors influencing the physical properties of the simple do some analysis, share them with you. 1, the polypropylene melt index and molecular weight distribution of polypropylene slice slice is the main quality indicators molecular weight, molecular weight distribution, isotactic degree, melt index, and ash content. Used for spinning PP slices, and its molecular weight is between 10, one thousand, 250000, but the practice has proved that the rheological properties of polypropylene melt when molecular weight at about 120000, which allows the spinning speed is high. Melt index reflects the melt rheological properties of a parameter, with polypropylene spun-bonded slice of melt index is usually between 10 to 50. Spinning process of this network, only get a draft of air strips, strips of draft restricted by the melt rheological properties, that is, the smaller the melt index, the greater the molecular weight of its rheological property is worse, the less the draft obtained by the strips, with the same spinneret hole melt spit out the silk denier shall also obtained under the condition, the greater the spun-bonded non-woven expressions are hard. If the melt index is larger, the melt viscosity decreased, good rheological property, drafting resistance decreases, under the condition of the same draft, drafting ratio increases. The macromolecular orientation degree increased, the breaking strength of the spun-bonded non-woven will improve, and strips down the size, material is soft. Under the condition of the same process, the polypropylene melt index is higher, its size is smaller, the greater the fracture strength. Heaviness in the molecular weight distribution of polymer molecular weight, Mw) And the number average molecular weight ( Mn) The ratio of the ( Mw／Mn) Value measure, according to the molecular weight distribution. Value, the smaller the molecular weight distribution, the rheological properties of the melt is more stable, spinning process is also more stable, is beneficial to improve the spinning speed, and has a lower viscosity of the melt elasticity and tensile, can reduce stress, spinning make PP are more likely to stretch and can obtain the fine denier fiber, and the uniformity of this network is good, good handle and evenness. 2, spinning temperature, spinning temperature set depends on the melt index and physical properties of product raw material requirements. Raw material melt index is higher, accordingly the higher spinning temperature, and vice versa. Directly related to the viscosity of the melt spinning temperature, the temperature is low. High melt viscosity, spinning difficult, prone to broken wires, jiang wire or coarse wire, affect the quality of the products. So, in order to reduce the viscosity of the melt and improve the rheological properties of the melt, commonly used way to raise the temperature. Spinning temperature had great effect on the structure and properties of the fiber. Lower spinning temperature, the higher the tensile viscosity of the melt, the greater the stretching resistance, strips, the more difficult it is to stretch to get the same denier fiber, low temperature when drafting airflow speed is higher. Therefore, under the same process conditions of other, lower spinning temperature, fiber is difficult to draw. Fiber denier is bigger, the molecular orientation degree is low, performance on the spun-bonded non-woven fabrics for low breaking strength, breaking elongation is bigger, feel is hard; Spinning at high temperature, fiber drawing is good, the fiber denier is small, the molecular orientation degree is higher, higher performance on spun-bonded non-woven fabrics for breaking strength, breaking elongation is small, soft. But it is worth noting that under the condition of certain cooling, if spinning temperature is too high, strips of cooling is not enough, in a short time in the process of drafting some fiber fracture, may be forming defect. In the actual production, the spinning temperature selection in 220 - It is advisable to 230 ℃. 3, cooling molding conditions in spun-bonded non-woven fabric forming process, the cooling speed of strips has a great influence on the physical properties of spun-bonded non-woven fabrics. Molten polypropylene came out from the spinneret can quickly evenly after cooling, the slow crystallization rate and crystallinity is low, the fiber structure is unstable dish liquid crystal structure, when drafting could reach draft is big, the orientation of the molecular chains is better, can further improve the degree of crystallinity, improve the strength of the fiber, reduce the elongation, performance on the spun-bonded non-woven fabrics for the fracture strength is larger, the low elongation, If the slow cooling, the fiber is stable monoclinic crystal structure, bad for fiber drawing, performance on the spun-bonded non-woven fabrics for breaking strength is small, elongation is bigger. So, in the process of forming, usually by increasing the cooling air volume, reduce the wire chamber temperature to improve the breaking strength of the spun-bonded non-woven, reduce the elongation. In addition, strips of cooling distance and its performance also has a close relationship, in the production of spun-bonded non-woven, generally choose cooling distance between 50 ~ 60 cm. Dongyang lai chi environmental protection technology co. , LTD. In order to 'seiko quality, fine service' as the concept, the main production and operation: spun-bonded non-woven fabric, elastic non-woven fabrics, medical non-woven, non-woven, SSS SMS non-woven fabrics and other products, is a professional non-woven fabric manufacturers.