SMS non-woven offline composite technology advantages and disadvantages

Offline composite technology refers to the first two spun-bonded and melt-blown technology respectively made methods of spun-bonded nonwoven fabric and melt-blown nonwovens, then after composite equipment will be two kinds of nonwovens composite together to form the SMS composite nonwovens. Offline composite SMS passes through 3 sets of equipment, and by the method of spun-bonded production line produce spun-bonded nonwoven fabric, by melt-blown production line produce melt-blown cloth, then two spun-bonded method middle clamping a layer of melt-blown nonwoven fabric cloth, through specialized composite rolling machine hot rolling bonding into three layer composite SMS. Off-line the main advantages of composite compound process basically has the following several advantages. ( 1) High flexibility, strong adaptability; ( 2) Particularly suitable for small order production; ( 3) If for rolling - mill roll form, can produce a variety of composite products, not just confined to the SMS. ( 4) Short line distance, small amount of maintenance; ( 5) Small investment, quick effect; ( 6) Benefit after functional finishing materials, not only ensure to use performance, and to avoid waste, cost savings, etc; ( 7) Suitable for complex high content of melt-blown nonwoven products, improve the water pressure resistance of the composite; ( 8) Can design the different pattern of roll in order to meet the corresponding user requirements. Off-line compound process faults composite technology also has its disadvantages, mainly has the following several aspects. ( 1) Because is melt-blown fabric rolls first uncoiling, melt-blown cloth gram weight can not be less than 10 g/m2, or due to low melt-blown fabric strength can't compound, thus limiting the SMS can only produce the spray layer above 10 g/m2 of SMS nonwovens; ( 2) Separate production of melt-blown fabric, because there is no support S cloth, is easy to be hurt, so it is difficult to guarantee the barrier property of the SMS non-woven fabrics and hydrostatic pressure resistance, it is difficult to ensure SMS non-woven fabric has good filtering performance, and such production uniformity of SMS non-woven fabrics is difficult to be controlled; ( 3) Because is the first to do the SMS fabric, in a composite, already can't adjust the SMS, so make it is hard to guarantee the physical properties of the SMS non-woven, especially the permeability and strength of the products. Even if found the problem, can adjust the process parameters is only rolling temperature and pressure. In September 2005 national conference on SMS quality standards, some offline composite manufacturers special mention powerful questions about SMS non-woven ( 4) Offline compound could not produce below 30 g/m2 thin SMS non-woven fabric; ( 5) Due to the gram weight of the spray layer can not less than 10 g/m2, so when doing the SMS, in order to avoid no separation between the SMS, thus to improve the working temperature of hot rolling mill and accordingly pressure, cause product feel is relatively hard, permeability is poorer, less powerful, especially not suitable for the production of protective clothing. If only consider product handle to adjust the process, is easy to cause the SMS delamination, product surface fuzz, this shortcoming is two steps production SMS is not easy to overcome problems, serious impact on the production of the application of SMS nonwovens ldpe-g-nvp; ( 6) Production is small. According to information, the nation's largest offline compound production line every year only 6000 t production; ( 7) Due to offline composite is made use of SMS fabric to finished product volume, and then to put volume, in so doing SMS non-woven fabrics, waste is bigger, cause the cost is bigger, is not conducive to competition in the market; ( 8) Offline composite product width is restricted, the domestic most offline composite line width in 1. 6 to 2. 4 m between, for application of factory, use 1. 6 m or 2. 4 m width of SMS non-woven fabrics to make a lot of waste; ( 9) Due to the SMS coil may not do long volume is very big, in such cases, due to the SMS fabric tension control, it's hard to do three long start and end at the same time put roll. And production couldn't carry a very high rate, domestic offline composite production speed is generally under 100 m/min; ( 10) Offline compound to product volume long cannot guarantee consistent, with joint in volume and the production of cloth, this will affect the customer use; ( 11) Production has color SMS, SMS is accomplished very hard accurate color, because of the color of the SMS fabric has been made, but not after composite color contrast, so almost no color allocate, entirely by experience in production, waste is big, color is not accurate.