Investigation of polishing mechanism of nanofibre buffing pad manufactured with modified melt blowing method

In order to decrease the fiber diameter and reduce the energy consumption in the melt-blowing process, a new slot die with internal stabilizers was designed. Using computational fluid dynamics technology, the new slot die was investigated. In the numerical simulation, the calculation data were validated with the laboratory measurement data. This work shows that the new slot die could increase the average velocity on the centerline of the air-flow field by 6.9%, compared with the common slot die. Simultaneously, the new slot die could decrease the back-flow velocity and the rate of temperature decay in the region close to the die head. The new slot die could reduce the peak value of the turbulent kinetic energy and make the fiber movements more gradual. With the one-dimensional drawing model, it proves that the new slot die has more edge on the decrease of fiber diameter than the common slot die.

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Effect of Introducing Long Chain Branching on Fiber Diameter and Fiber Diameter Distribution in Melt Blowing Process of Polypropylene

International Polymer Processing ◽

10.1515/ipp-2020-3922 ◽

2021 ◽

Vol 36 (4) ◽

pp. 403-409

Author(s):

K. Iiba ◽

W. Takarada ◽

T. Kikutani

Keyword(s):

Fiber Diameter ◽

Viscosity Reduction ◽

Diameter Distribution ◽

Polymer Rheology ◽

Melt Blowing ◽

Melt Flow Rate ◽

Long Chain Branching ◽

Molten Polymers ◽

Uniform Diameter ◽

Long Chain

Abstract In the melt blowing process, the molten polymers extruded from nozzles are elongated by high-velocity and high-temperature air flow. In this study, with the aim of stabilizing the melt blowing process for producing nonwoven webs with fine diameter fibers, the effect of the control of polymer rheology by the introduction of either low melt flow rate (MFR) polypropylene (PP) or long chain branched PP (LCB-PP) to regular high MFR PP was investigated. Introduction of low MFR PP into regular PP increased shear viscosity and fibers of larger diameter were produced in the melt blowing process, while introduction of low MFR LCB-PP suppressed the elongational viscosity reduction with the increase of strain rate, and eventually spinning was stabilized. It was found that the blending of an optimum amount of LCB-PP to regular PP caused the stabilization of the melt blowing process. As a result, the formation of nonwoven webs consisting of fine fibers of rather uniform diameter distribution could be achieved.

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Simulation of jet velocity in the melt-blowing process using the coupled air–polymer model

Textile Research Journal ◽

10.1177/0040517518809048 ◽

2018 ◽

Vol 89 (16) ◽

pp. 3221-3233 ◽

Cited By ~ 2

Author(s):

Xibo Hao ◽

Hui Huang ◽

Yongchun Zeng

Keyword(s):

High Speed ◽

Flow Model ◽

Processing Parameters ◽

High Speed Photography ◽

Critical Factors ◽

Polymer Model ◽

Melt Blowing ◽

Two Phase ◽

Jet Velocity ◽

Jet Velocities

The polymer jet velocity is one of the most basic and critical factors in the melt-blowing process and has always been difficult to measure online. Much effort has been made on the numerical prediction of the jet velocity. However, little work has involved the complex interaction between the air flow and the polymer. Here, the Level-Set method is used to develop the coupled air–polymer two-phase flow model, and to simulate the polymer jet motion in the melt-blowing process considering the coupled effect of the air and polymer. Meanwhile, high-speed photography is adopted in the experiments to verify the simulation results. The x- and y-components of the jet velocities and the whipping amplitude of the jet motion are discussed. The rapid increase of jet velocity and the decrease of jet diameter show that most attenuation of the polymer jet occurred within a distance close to the die (10 mm). Based on the model, the effects of the processing parameters on the jet velocity are examined numerically.

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Optimal design for the dual slot die in melt blowing process

Thermal Science ◽

10.2298/tsci1405714w ◽

2014 ◽

Vol 18 (5) ◽

pp. 1714-1715

Author(s):

Li-Li Wu ◽

Ting-Ting Cheng ◽

Chuan Xu ◽

Ting Chen

Keyword(s):

Experimental Design ◽

Optimal Design ◽

Flow Field ◽

Design Method ◽

Air Flow ◽

Variance Analysis ◽

Orthogonal Experimental Design ◽

Melt Blowing ◽

Experimental Design Method ◽

Slot Die

The parameters of the dual slot die in an industrial melt blowing equipment are designed optimally using the orthogonal experimental design method. The air flow fields of different die parameters are simulated. Effects of the die parameters are analyzed using variance analysis. The results show that the inset distance and slot width have significant effects on the air flow field while effect of the slot angle is unremarkable.

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