熔纺双组分超细纤维成型工艺及其应用研究进展OA北大核心CSTPCD

In recent years,ultra-fine fiber nonwovens are widely used in various fields due to their excellent performances,and play a vital role in in our daily life.Currently,there are various methods to produce ultra-fine fibers,such as electrospinning,centrifugal spinning,flash spinning and melt spinning.Among them,melt-spun bicomponent ultra-fine fibers have broadly drawn attention due to the selective diversity of combinations of raw materials and processing techniques.In addition,melt-spun bicomponent fibers are dominant in the market because of their ability to be produced on a large scale.However,industrial producing of melt-spun bicomponent ultra-fine fibers usually suffers from problems such as high energy consumption,large diameter and environmental issue,which limit their high-quality development and applications in future.During the practical processing,selection of different polymers,use age of spinning packs of different sizes,and adjustment of different spinning parameters have significant impacts on the formation of melt-spun bicomponent ultra-fine fibers.Therefore,it is of great significance to regulate the influencing factors in the forming process of bicomponent ultra-fine fibers to further improve their comprehensive performances. In order to understand the nature of melt-spun bicomponent ultra-fine fibers more comprehensively,this paper took segmented-pie fibers and sea-island fibers as the research matrix,explored the spinning and forming mechanism of melt-spun bicomponent ultra-fine fibers and the influencing factors,elaborated the diverse open fiber processes of melt-spun bicomponent ultra-fine fibers,and summarized the applications of melt-spun bicomponent ultra-fine fibers in different fields.As for the spinning process,by using conjugated melt spinning with different types of melt distribution systems,segmented-pie fibers and figured sea-island fibers could be prepared respectively.In the meanwhile,the forming mechanism of unfigured sea-island fibers was clearly revealed.In the spinning process,blended polymer droplets were stretched into long or elliptical shapes in the spinning pack,which is the main reason for the uneven diameters of unfigured sea-island fibers compared to figured sea-island fibers.There are notable differences in the properties of figured and unfigured sea-island fibers.Moreover,the finer fiber diameters can be obtained by increasing the drawing multiplier and improving the properties of the polymer feedstock.As for fiber splitting process,there are three types of fiber splitting methods,namely mechanical,chemical and thermal means.It was found that energy consumption of fiber splitting can be effectively reduced by decreasing the interfacial bonding between polymers.Significantly,the use of water-soluble polyvinyl alcohol(PVA)points a way for developing green bicomponent ultra-fine fibers.Due to the low dimension,high specific surface area,and facile functional finishing,melt-spun bicomponent fibers have a wide range of applications such as ultra-fine fiber artificial leather,air filer,medical and health materials. Melt-spun bicomponent ultra-fine fibers show excellent comprehensive performance and have wide application prospects.However,there are still several tasks for preparing melt-spun bicomponent ultra-fine fibers,such as reducing energy consumption and pollution during melt spinning and fiber splitting,and preparing melt-spun bicomponent ultra-fine fibers with finer diameters and excellent properties.In the selection of raw materials,polymer raw materials with different excellent properties should be further developed,so as to broaden the diversified combinations of raw materials for melt-spun bicomponent fibers;in the process of preparation,the research and development of precision components and the optimization of molding process should be carried out,so as to improve the performance of melt-spun bicomponent fibers and realize the further refinement the fiber diameters;about the fiber splitting,along with the concept of green environmental protection,low energy consumption,chemical-free reagents and efficient green fiber splitting process should be developed.Water-soluble fiber opening,as a green fiber opening method,provides a good development direction for bicomponent ultra-fine fibers.Water-soluble polymers provide a good direction for the development of melt-spun bicomponent ultra-fine fibers.And with the continuous development of the nonwoven industry,it is believed melt-spun bicomponent ultra-fine fibers will develop toward the direction of green,multi-function and high performance in the future,so as to better benefit mankind and society.