Interpretation of the preparation method of meltblown nonwovens

Meltblown nonwovens technology has developed rapidly, especially in recent years. With the rapid development of industry and the strengthening of environmental protection, the meltblown nonwovens market has become larger and larger. The characteristics shown by the characteristics of its superfine fibers. In many industries, civilian fields have been discovered and widely used. Melt-blown non-woven fabrics are widely used in fields such as filter materials, oil-absorbing materials, sound insulation materials, medical sanitary materials, industrial and household wipes, and thermal insulation materials. With the rapid development of industrial technology, industrial pollution has become more and more serious, and people's requirements for filter materials have become higher and higher. The traditional melt-blown non-woven fabric preparation method is relatively complicated, the molding effect is not good, and the application effect is not good, which brings inconvenience to people's use. SUMMARY OF THE INVENTION In view of the shortcomings in the prior art, the purpose of the present invention is to provide a method for preparing a meltblown nonwoven fabric, which has good molding effect, simple preparation process, improved production efficiency, and greatly facilitated people's use. In order to achieve the above objectives, the present invention is achieved through the following technical solutions: the preparation method of meltblown nonwovens, including the following steps: (I) raw material preparation: polymer chips are fully dried before melt spinning to make them The moisture content is less than 0.5%; (2) Melt extrusion: The high polymer chips are fed into the screw extruder for melt extrusion, and sprayed out through the special-shaped melt blown die device. The length-to-diameter ratio of the screw extruder is 25-40:1, the box temperature is 180-350°C, the feeding section is 140-180°C, the compression section is 160-300°C, and the metering section is 200-400° C, the screw speed is 10~110r/min, and the metering pump speed is 10~60r/min; (3) Spinning into a web: the melt jetted by the melt blown die is stretched by the high temperature hot air flow on both sides, thus The formed superfine fibers are self-adhesive to form a web in the natural cooling process to obtain the meltblown nonwoven fabric with a grammage of 20 to 200 g/m2. The high-temperature hot air has a temperature of 80 to 350°C and a flow rate of 80 to 1000 m/s. The raw materials in the step (I) are polypropylene (PP), high-density polyethylene (HDPE), low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), polyvinyl chloride (PVC), poly Polyethylene terephthalate (PET), polytrimethylene terephthalate (PTT), polybutylene terephthalate (PBT), polyamide 6 (PA6), polyamide 66 (PA66), Two or more of polylactic acid (PLA) and polyphenylene sulfide (PPS). The meltblown nonwoven fabric prepared in the step (3) is composed of special-shaped fibers, and the cross-sections of the special-shaped fibers are multi-lobed (three-lobed and above) and hollow. The circumscribed radius R of the cross-section of the shaped fiber is 1-8 μm. The inner diameter of the hollow fiber is 0.1-1 μm, and the outer diameter is 0.2-1.1 μm. The beneficial effects of the present invention: good molding effect, simple preparation process, improved production efficiency, and greatly facilitated people's use. DETAILED DESCRIPTION OF THE EMBODIMENTS In order to make the technical means, creative features, objectives and effects of the present invention easy to understand, the present invention will be further explained in conjunction with specific embodiments. This specific embodiment adopts the following technical solutions: a method for preparing a meltblown nonwoven fabric, including the following steps: (I) raw material preparation: polymer chips are fully dried before melt spinning to make their moisture content less than 0.5%; 2) Melt extrusion: High polymer chips are fed into the screw extruder for melt extrusion, and then ejected through the special-shaped melt blowing die device. The length-to-diameter ratio of the screw extruder is 25-40:1, the box temperature is 180-350°C, the feeding section is 140-180°C, the compression section is 160-300°C, and the metering section is 200-400° C, the screw speed is 10~110r/min, and the metering pump speed is 10~60r/min; (3) Spinning into a web: the melt jetted by the melt blown die is stretched by the high temperature hot air flow on both sides, thus The formed superfine fibers are self-adhesive to form a web in the natural cooling process to obtain the meltblown nonwoven fabric with a grammage of 20 to 200 g/m2. The high-temperature hot air has a temperature of 80 to 350°C and a flow rate of 80 to 1000 m/s. It is worth noting that the raw materials in the step (I) are polypropylene (PP), high-density polyethylene (HDPE), low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), polyvinyl chloride (PVC), polyethylene terephthalate (PET), polytrimethylene terephthalate (PTT), polybutylene terephthalate (PBT), polyamide 6 (PA6), polyamide Two or more of 66 (PA66), polylactic acid (PLA) and polyphenylene sulfide (PPS). It is worth noting that the meltblown nonwoven fabric prepared in the step (3) is composed of special-shaped fibers, and the cross-sections of the special-shaped fibers are multi-lobed (three-lobed and above) and hollow. It is worth noting that the radius R of the circumscribed circle of the cross-section of the profiled fiber is 1-8 μπι.