Meltblown technology for production of polymeric microfibers/nanofibers: A review

Abstract

This work summarizes the current state of knowledge in area of meltblown technology for production of polymeric nonwovens with specific attention to utilized polymers, die design, production of nanofibers, the effect of process variables (such as throughput rate, melt rheology, melt temperature, die temperature, air temperature/velocity/pressure and die-to-collector distance and speed) with relation to nonwoven characteristics as well as to typical flow instabilities such as whipping, die drool, fiber breakup, melt spraying, flies, generation of small isolated spherical particles, shots, jam and generation of nonuniform fiber diameters.

Melt Electrospinning of Nanofibers from Medical‐Grade Poly(ε‐Caprolactone) with a Modified Nozzle

“…Another melt‐processing technology for the manufacture of nanofibers is melt blowing [ 25 ] where some of the smallest fiber sizes are 440 and 300 nm using poly(butylene terephthalate) and polypropylene [ 25,26 ] respectively. The production rate for melt blown fabrics is substantially greater than MES shown here, however conversely the expense and kilogram quantity of raw material required for melt blowing makes the use of GMP‐manufactured polymer economically prohibitive for research purposes.…”

“…There are several manufacturing technologies that result in small diameter fibers [ 41 ] from both the melt and from solvent. Such processing technologies are at different stages of development and include solution electrospinning, [ 22 ] pressurized gyration, [ 42 ] melt blowing, [ 25 ] forcespinning, [ 43 ] and magnetospinning. [ 44 ] The diversity of manufacturing options for small diameter fibers is further increased with the approach used here and provides another processing option that could better suit a specific manufacturing need.…”

“…[ 44 ] The diversity of manufacturing options for small diameter fibers is further increased with the approach used here and provides another processing option that could better suit a specific manufacturing need. While industrially successful processes such as melt blowing have become a critical part of N95 masks for air filtration, there are substantial costs in building such equipment [ 25 ] or processing gram‐quantities of specialty polymers. While current manufacturing throughput for MES is notably low in this study, the placement of the electrospun fibers on a specific spot on the collector is highly predictable and the head small enough to be employed within a hybrid manufacturing approach (shown with MEW as an example in this study) for biomaterial applications where defined barriers are of interest.…”

Particle Image Velocimetry (PIV) Investigation of the Turbulent Airflow in Slot-Die Melt Blowing

“…Although the studies on the fiber whipping motion are less than those on the flow field, discoveries on fiber whipping can be briefly summarized as follows: (1) the fiber path during the slot-die melt blowing is composed of alternating left-right arcs [25]; (2) the fiber path laterally expands as it moves to the collector [16,26]; and (3) the lateral expansion of the fiber path is anisotropic [16]. More detailed descriptions of melt-blown fiber whipping also can be found in the reviews of Hao [27] and Drabek [28]. However, the special fiber whipping motion in slot-die melt blowing has not been thoroughly explained so far.…”

A fundamental rule: Determining the importance of flow prior to polymer crystallization

“…On the other hand, in typical polymer processing methods such as polymer extrusion 13,14 , injection molding 15,16 , film blowing 17,18 , fibre production 19 ,and extrusion-based three-dimensional (3D) printing 20 , processing temperatures are usually above the melting point of the polymer, and crystallization follows in the absence of flow under non-isothermal conditions. Thus, the nucleation rate is typically non-constant, depending on both the decaying temperature and the flow-induced polymer deformation, which will begin to relax at the cessation of flow.…”