This work summarizes the current state of knowledge in the 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 the throughput rate, melt rheology, melt temperature, die temperature, air temperature/velocity/pressure, 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.

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

Melt blowing is an industrially important process in producing microfibrous nonwovens. Over the past decades, there has been a considerable amount of fundamental research on this technique, driven ...

A Review on the Studies of Air Flow Field and Fiber Formation Process during Melt Blowing

Melt blowing is an industrial approach for producing microfibrous nonwoven materials utilizing high-speed air to attenuate polymer melt. The melt-blowing air flow field which is widely believed to be turbulence determines the process of fiber formation. In this study, the turbulent air flow field in slot-die melt blowing was experimental measured by hot-wire anemometer. The fluctuations of air velocity and temperature, the mean velocity and mean temperature were measured and analyzed; moreover, the relationship between turbulent air flow field and fiber formation in melt blowing was discussed and predicted. In the last part of this paper, the coupling effect of air temperature and velocity was studied tentatively, results showed that air temperature not only had an enhanced effect on velocity, but contributed to the fluctuation of velocity. This work shows that the fluctuating characteristics of air velocity and temperature have dominant effect on fiber motion and the evenness of fiber diameter.

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Turbulent air flow field in slot-die melt blowing for manufacturing microfibrous nonwoven materials

An air-jet How field model of the dual slot die in the melt blowing nonwoven process is proposed and solved numerically with the finite difference method. The effects of dual slot die design parameters on velocity and temperature distributions in the melt blowing flow field are investigated. The computation results of the distributions of the x-compo nents of air velocity and air temperature coincide well with our experimental data. The results show that a smaller angle α, a larger slot width e, and a narrower head width f will all result in higher x-components of air velocity and higher air temperatures, which are beneficial to the air drawing of the polymer melt and thus to reduced fiber diameter. The results show the great potential of this research for computer-assisted design in the melt blowing nonwoven technology.

Modeling the Air-Jet Flow Field of a Dual Slot Die in the Melt Blowing Nonwoven Process

Preparation and properties of poly(lactic acid) fiber melt blown non-woven disordered mats

An air drawing model of a polymer in a melt blowing process is presented and solved by introducing the numerical computation results of the air jet flow field of the dual slot die. The model's prediction of fiber diameter tallies well with the experimental data. The effects of processing and die design parameters on fiber diameter are discussed. A lower polymer flow rate, higher initial polymer temperature, higher initial air velocity, higher initial air temperature, smaller angle between the slot and the spinneret axis, smaller width of the die head, and larger width of the slot can all yield finer fibers.

Xiubao Huang

Papers

Modeling Polymer Air Drawing in the Melt Blowing Nonwoven Process