Interpretation of the preparation method of meltblown nonwovens

The technology of meltblown nonwovens has developed rapidly, especially in recent years, with the rapid development of the industry and the strengthening of environmental protection, the market of meltblown nonwovens is getting bigger and bigger. The characteristics exhibited by its microfiber characteristics. It has been found and widely used in many industrial and civil fields. Meltblown nonwovens are widely used in filter materials, oil absorbing materials, sound insulation materials, medical hygiene materials, industrial and household wipers, thermal insulation materials and other fields. With the rapid development of industrial technology, industrial pollution is becoming more and more serious, and people's requirements for filter materials are also getting higher and higher. The preparation method of the traditional meltblown nonwoven fabric is relatively complicated, the forming 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 deficiencies in the prior art, the purpose of the present invention is to provide a method for preparing a meltblown nonwoven fabric, which has good forming effect, simple preparation process, improved production efficiency, and is greatly convenient for people to use. In order to achieve the above object, the present invention is realized by the following technical solutions: the preparation method of melt-blown non-woven fabric, comprises the following steps: (1) raw material preparation: high polymer slices are fully dried before melt spinning to make it The water content is less than 0.5%; (2) melt extrusion: the high polymer chips are sent into the screw extruder for melt extrusion, and are ejected through a special-shaped melt-blown die device. The length-diameter ratio of the screw extruder is 25-40: 1, and the box temperature is 180-350°C, the feeding section is 140~180°C, the compression section is between 160 and 300°C, 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 sprayed from the melt-blown die is stretched by the high-temperature hot air flow on both sides, thereby The formed ultrafine fibers are self-bonded to form a fiber web during the natural cooling process, and the described grammage of 20-200g/m2 meltblown nonwoven is obtained. High temperature hot air temperature is 80~350°C. The flow rate is 80-1000m/s. The raw materials in the described step (1) are polypropylene (PP), high density polyethylene (HDPE), low density polyethylene (LDPE), linear low density polyethylene (LLDPE), polyvinyl chloride (PVC), polyvinyl chloride Ethylene 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 melt-blown non-woven fabric prepared in the step (3) is composed of special-shaped fibers, and the cross-section of the special-shaped fibers is multilobal (three leaves and above) and hollow. The circumcircle radius R of the cross-section of the special-shaped fiber is 1?8μπι. The inner diameter of the hollow fiber is 0.1-1μπι, the outer diameter is 0.2-1.1μπι. The beneficial effects of the invention are as follows: the molding effect is good, the preparation process is simple, the production efficiency is improved, and it is greatly convenient for people to use. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In order to make the technical means, creative features, goals and effects realized by the present invention easy to understand, the present invention will be further described below with reference to the specific embodiments. This specific embodiment adopts the following technical scheme: the preparation method of meltblown non-woven fabric, comprises the following steps: (1) raw material preparation: high polymer chip is fully dried before melt spinning, and its moisture content is less than 0.5%; ( 2) Melt extrusion: The high polymer slices are sent into the screw extruder for melt extrusion, and are ejected through the special-shaped melt-blown die device. The length-diameter ratio of the screw extruder is 25-40: 1, and the box temperature is 180-350°C, the feeding section is 140~180°C, the compression section is between 160 and 300°C, 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 sprayed from the melt-blown die is stretched by the high-temperature hot air flow on both sides, thereby The formed ultrafine fibers are self-bonded to form a fiber web during the natural cooling process, and the described grammage of 20-200g/m2 meltblown nonwoven is obtained. High temperature hot air temperature is 80~350°C. The flow rate is 80-1000m/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 66 (PA66), two or more of 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-section of the special-shaped fibers is multi-lobal (three leaves and above) and hollow. It is worth noting that the circumscribed radius R of the cross-section of the shaped fiber is I?8μπι. In addition, the inner diameter of the hollow fiber is 0.1-1μπι, the outer diameter is 0.2-1.1 μmo. The fibers produced by this specific embodiment are very thin, and the melt-blown cloth has a large specific surface area, small voids and large porosity, so its filterability, shielding, thermal insulation and oil absorption. Such application characteristics are difficult for non-woven fabrics produced by other separate processes. Therefore, meltblown nonwovens are widely used in medical and industrial masks, thermal insulation materials, filter materials, medical and health materials, oil-absorbing materials, wipes, battery separators and sound insulation materials. The basic principles and main features of the present invention and the advantages of the present invention have been shown and described above. Those skilled in the art should understand that the present invention is not limited by the above-mentioned embodiments, and the descriptions in the above-mentioned embodiments and the description are only to illustrate the principle of the present invention. Without departing from the spirit and scope of the present invention, the present invention will have Various changes and modifications fall within the scope of the claimed invention. The claimed scope of the present invention is defined by the appended claims and their equivalents.