A New Modified Method to Obtain a High Melt Index of PLA Polymer and Preparation of Melt-Blown Nonwoven Cloth

Qian Lin,Jianyong Feng,Lixia Zhao 한국섬유공학회 2023 Fibers and polymers Vol.24 No.10

Due to the low melt index of polylactic acid (PLA) polymer, it is difficult to melt-blown processing. Here, a new modified method to obtain a high melt index of PLA polymer and melt-blown nonwoven cloth was studied. PLA polymers are modified by the thermally degraded method of stannous octoate (Sn(Oct)2) and polyethylene glycol (PEG) to obtain a high melt index (1054 g/10 min) in comparison with a low melt index (23 g/10 min) of original unmodified PLA polymer. The fiber of modified PLA polymer melt-blown cloth is obviously thinner, having sub-micron fibers, the smallest fiber is about 200 nm. From our test, modified PLA polymer melt-blown cloth has good oil absorption, oil–water separation, and potential air filtration property. In terms of degradation, the modified PLA polymer melt-blown cloth showed excellent degradation performance in basic aqueous solutions at 55 °C at pH 12, reaching a degradation rate of around 95% at 60 h.

멜트블로운 폴리프로필렌/실리카 에어로겔 부직포의 제조와 단열 특성 분석

신정우,정영규,Shin, Jung Woo,Jeong, Young Gyu 한국섬유공학회 2018 한국섬유공학회지 Vol.55 No.6

To develop heat insulation fabrics with lightweight, low volume and excellent thermal insulation properties, in this study, a binder-free polypropylene/silica aerogel nonwoven fabric with an area density of ${\sim}79.7g/m^2$ was fabricated via a facile melt-blowing process, and its structure, thermal conductivity and thermal insulation properties were investigated. For comparison, a polyester hollow fiber nonwoven having a similar area density of ${\sim}84.6g/m^2$ was prepared by needle-punching. Additionally, a series of composite nonwoven fabrics was prepared by layering the melt-blown polypropylene/silica aerogel nonwoven and the polyester hollow fiber nonwoven in various combinations, and their thermal insulation properties and thermal conductivity were analyzed. Scanning electron microscopic analyses revealed that 5 wt% silica aerogel added during the melt-blown process was adhered well to polypropylene fiber surfaces of the nonwoven fabric. As a result, the melt-blown polypropylene/silica aerogel nonwoven fabric exhibited a low thermal conductivity of $43mW/m{\cdot}K$ and relatively high level of thermal insulation performance, although its thickness (~1.5 mm) was lower than that (~2.2 mm) of needle-punched polyester hollow fiber nonwoven with a similar area density. The thermal conductivity was lowered and thermal insulation performance was improved, as the melt-blown polypropylene/silica aerogel nonwoven fabric was layered. It was also found that increasing the number of melt-blown polypropylene/silica aerogel nonwoven fabric layers in the composite nonwoven fabrics layered in various combinations decreased the thermal conductivity and improved the thermal insulating properties.

Investigation on the Airflow Fields of New Melt-blown Dies with Rectangular Jets

Yudong Wang,Fang Jiang,Wan’e Ning,Sheng Xie,Changchun Jiang 한국섬유공학회 2022 Fibers and polymers Vol.23 No.10

In order to reduce the fiber diameter and the energy consumption in the melt-blowing process, three new slot dies(slot die with air accelerator, slot die with stabilizers and slot die with extensions) are designed. The airflow fields of thesedies have been numerically calculated and experimentally verified. The results reveal that the slot die with stabilizers and slotdie with extensions have higher average stagnation temperatures, average air pressure and average turbulent kinetic energythan those of the common slot die. Compared with the common slot die, the slot die with air accelerator could increase theaverage stagnation temperature on the spinning line, however, its average pressure is reduced and the average turbulentkinetic energy is locally increased. By comprehensively comparing the average stagnation temperature, average air pressureand average turbulent kinetic energy on the spinning lines of these slot dies, the new slot die with stabilizers is the mostconducive to the attenuation of the melt-blowing fibers and the reduction of energy consumption. The research in this workcan have strong guiding significance for the optimization of die structure and the attenuation of melt-blowing fibers.

Air Recirculation and Its Effect on Microfiber Spinning in Blunt-Die Melt Blowing

Sheng Xie,Guojun Jiang,Xianyan Wu,Yaping Wang,Haisu Fang,Baoqing Shentu 한국섬유공학회 2021 Fibers and polymers Vol.22 No.3

In the present work, approaches of the Computational Fluid Dynamics (CFD) simulation, the Particle ImageVelocimetry (PIV) measurement, and the spinning experiment were applied to investigate the phenomenon of air recirculation inblunt-die melt-blown airflow. Firstly, the characteristics of air recirculation were explored by CFD simulation. The simulationresults predicted that the air recirculation generated a lateral air velocity along the nose-piece direction. Then, the aircirculation was experimental verified by using PIV technique. The PIV results confirmed the predicted conclusions of CFDsimulation. Finally, the effect of air recirculation on the microfiber spinning during the melt-blown process was experimentallyinvestigated by a spinning experiment using a blunt die with nose-piece width of 2.56 mm. The spinning results indicated thatthe air circulation had a tendency of splitting the normal polymeric stream, which played negative effect on the continuity ofmicrofiber spinning. This work is expected to provide some clues to melt-blown die design and the quality control ofnonwoven products.

Optimization of Processing Parameters for Particle Filtration Efficiency of Polypropylene Melt-blown Fabric

Taijun Jiang,Guangsheng Zeng,Can Hu,Cong Meng,Yi Chen 한국섬유공학회 2021 Fibers and polymers Vol.22 No.4

Polypropylene melt-blown fabric as the core filter materials plays an important role in manufacturing civil andmedical epidemic prevention products. The aim of this study was to optimize and control the particle filtration efficiency andapparent surface quality of the melt-blown fabric from the perspectives of electret masterbatch composition and processingparameters. Magnesium stearate and fumed silica were used as the electret to manufacture polypropylene melt-blown fabric. The layout and charge voltage of the electret device was taken as the variables to optimize and improve the particle filtrationefficiency and bulkiness coefficient of the fabric. The temperature of the barrel and die was controlled to enhance the surfacequality and corresponding particle filtration efficiency. The results showed that a combination of organic magnesium stearateand inorganic fumed silica could obtain a balance between particle filtration efficiency and smooth processing without beingjammed. Increasing the charge voltage and rearranging the position of the charge wires could significantly enhance theparticle filtration efficiency. A better particle filtration efficiency and reasonable bulkiness coefficient could be obtained bycontrolling the diameter of the filaments by regulating the temperature of the barrel and die as well as the suction intensity. The results obtained from this study can offer valuable references in optimization of electret master batch formulation andprocessing parameters for melt-blown fabric production with different resin.

멜트블로운 부직포를 이용한 전열교환소자의 특성 연구 (II) -폴리프로필렌과 나일론 멜트블로운 부직포 특성 고찰-

이창환,이종현,권은희,이경주,손은종,김성훈,Lee, Chang-Hwan,Lee, Jong-Hyun,Kwon, Eun-Hee,Lee, Kyung-Ju,Son, Eun-Jong,Kim, Seong-Hun 한국섬유공학회 2010 한국섬유공학회지 Vol.47 No.6

An enthalpy exchanger made from meltblown was prepared by a range of physical treatments to identify the production potential, and its characteristics were compared with an enthalpy exchanger based on polypropylene (PP). SEM revealed excellent compatibility between nylon and PVA. Various measurements were carried out as a function of the calendering temperature and speed, content of moisture absorbent, and concentration of water soluble polymer. The optimum conditions for the enthalpy exchanger made from nylon meltblown were as follows: a calendering temperature of $124^{\circ}C$, calendering speed of 2 m/min, and pick-up of 8~10%. The tensile strength of nylon was higher than that of the PP materials. In conclusion, nylon melt-blown nonwoven has greater potential than PP melt-blown nonwoven and can be used as a substitute in commercial paper type heat exchangers.

Experimental and Simulation Investigation on the Effect of Slot Angle on the Flush Sharp Die Performance during Melt Blowing

Xibo Hao,Guojun Jiang,Jin Tao,Guoliang Liu,Sheng Xie 한국섬유공학회 2022 Fibers and polymers Vol.23 No.10

Die configuration is one of the most important factors that determine the polymer jet attenuation during meltblowing. To find the optimum slot angle, we investigated the effects of sharp die slot angles (60 °, 50 °, 40 °) on the polymerjet attenuation experimentally and numerically. A model which incorporated the air-polymer coupling effect was built basedon phase field method to investigate the die performance. In the experiment, sharp dies with different slot angles werefabricated and adopted for producing melt-blown nonwovens. The SEM and filter efficiency measurement, and numericalanalysis demonstrated that the 60 ° sharp die has the best performance in polymer jet attenuation.

멜트블론을 이용한 올레핀계 접착층의 특성에 관한 연구

김창훈,최세진,이현석,김한성,Kim, Chang Hun,Choi, Se Jin,Lee, Hyun Seok,Kim, Han Seong 한국섬유공학회 2016 한국섬유공학회지 Vol.53 No.2

This study investigated the interrelationships between some properties of low-density polyethylene (LDPE) web fibers produced by the melt-blown technique. Variations in the LDPE fiber's diameter and uniformity were correlated against variations in throughput pressure, hot air pressure, and nozzle temperature. The bond strength of the LDPE web adhesion layer was found to be lower than that of LDPE film. However, the LDPE web adhesion layer's air permeability was found to be significantly higher than - as much as 260 times higher - that of LDPE film. The results suggest that melt-blown LDPE web fibers are useful for producing multi-function products.

멜트블로운 부직포의 정전 처리조건이 여과효율에 미치는 영향

심현주,강준영,장선호,오태환,Shim, Hyun-Joo,Kang, June-Young,Jang, Sun-Ho,Oh, Tae-Hwan 한국섬유공학회 2008 한국섬유공학회지 Vol.45 No.2

The air filter media were prepared using light polypropylene melt- blown nonwovens and then, corona charge was applied to achieve with low pressure drop and high filtration efficiency air filter. The processing variables for the corona treatments were set up, such as, the electric potential distance between the electrode and the nonwoven, the number of charging, the sequences of charging surfaces, and the concentration of ferro-dielectric nano particles. The electrical potential was applied in the range of 15 to 35 kV, the number of charging was 1 to 4 times with and without turn over the charging surface, the concentration of ferro-dielectric nano particle solutions were 0.5 to 1.5% (W/V). In this research, the most probable processing conditions gave a clue to make a HEPA filter when the media was plied 5 times. This HEPA filter showed its initial pressure drop be 7.7 mmAq and filtration efficiency be 99.99%.

나노 입자 첨가에 따른 정전 멜트블로운 부직포의 여과효율에 관한 연구

장선호,심현주,Jang, Sun-Ho,Shim, Hyun-Joo 한국섬유공학회 2008 한국섬유공학회지 Vol.45 No.5

We designed a filter media which could collect of submicron size particles by applying electrostatic charge. To meet our proposed design, three different types of nano-scaled materials such as nonconductor ($SiO_2$), conductor ($Al_{2}O_{3}$), ferroelectric material ($BaTiO_3$) were incorporated into the melt-blown nonwovens made of micro fiber. Polypropylene melt-blown nonwovens, basis weights of $15\;g/m^2$ and $20\;g/m^2$, were prepared. The nano particles were diffused in the ethanol and then the electro sprayed on the nonwoven fabrics to be uniformly dispersed. The specimens containing nano particles were conditioned for three hours in the vacuum drying oven. To meet our purpose, the specimens were corona charged to develop the static electricity. The charging density and filtration efficiency of the filter media were investigated with various experimental conditions: such as types of additives and their concentrations. It was shown that the charging density and filtration efficiency were increased with increasing the basis weight of the samples. The filter media incorporated with ferroelectric particles showed the most desirable results compared with the other two additives.