Sheath−Core Differences Caused by Rapid Thermoxidation during Melt Blowing of Fibers

Kelley, Stephen L.; Shambaugh, Robert L.

doi:10.1021/ie970549f

Cited by 5 publications

(4 citation statements)

References 14 publications

(15 reference statements)

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“…Decreases in fiber diameter with increases in die temperature were also observed by other researchers, see Figure 15, [1,5,11,13]. Data shown in Figure 15 for PET 'A', as triangle pointing up, was produced at a higher polymer throughput rate than data for PET 'A' depicted with an 'X.'…”

Section: Influence Of Die Temperaturesupporting

confidence: 72%

Study of Meltblown Structures Formed by Robotic and Meltblowing Integrated System: Impact of Process Parameters on Fiber Diameter Distributions

Farer

Batra

Ghosh

et al. 2003

International Nonwovens Journal

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In previous publication, the influence of process parameters on the fiber orientation of the meltblown web was evaluated [4]. The meltblown webs were formed using Robotic Fiber Assembly and Control System (RFACS), which is described in previous publications [3,4]. In this paper, parametric studies evaluating the effect of polymer throughput rate, attenuating air pressure and temperature, and die temperature, on fiber diameter distributions of meltblown webs from polypropylene produced by RFACS are reported. Fiber diameters were determined by analyzing fabric images obtained through scanning electron microscopy (SEM). Under the specific conditions explored, the fraction of fibers of diameter smaller than 10 microns (µm) can increase by 72% with a 7.9 x 10 -2 g/min/hole (82%) reduction in throughput. A 54% increase of the same can be observed with a 2.8 bar (400%) increase in attenuating air pressure. A change of 45ºC (16 %) in air temperature is shown not to significantly affect fiber diameters produced, while an increase of 67ºC (26%) in die temperatures can result in an increase of 17% in the fraction of fibers of diameter smaller than 10µm. All fiber diameter distributions are shown to be unique to the condition evaluated as no overlap across distributions for changes in a given parameter is observed. Further fiber fraction smaller than 10 µm data is also shown to be unique to each parameter evaluated.

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Section: Influence Of Die Temperaturesupporting

confidence: 72%

Study of Meltblown Structures Formed by Robotic and Meltblowing Integrated System: Impact of Process Parameters on Fiber Diameter Distributions

Farer

Batra

Ghosh

et al. 2003

International Nonwovens Journal

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“…Thirdly, the relationship between the fibre deformation and F′ is the most difficult one to clarify, because it involves the adhesive’s composition and the polymer’s mass weight distribution, both of which determine how the fibre reacts under the application of external forces. Even the oxidative degradation the polymer fibre undergoes when exposed to the air jets, which produces a stratification in the fibre’s cross section, can affect fibre breakup [21]. Nevertheless, as the fibre is squeezed, it exhibits both extensional and shear deformation, both of which are limited by the polymers molecular-weight [5].…”

Section: Resultsmentioning

confidence: 99%

Experimental study of fibre breakup and shot formation in melt blowing nozzle designs

Formoso

Rivas

Beltrame

et al. 2020

Journal of Industrial Textiles

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The high demand for quality in the manufacture of absorbent hygiene products requires the adhesive bonds between layers to be as uniform as possible. An experimental study was conducted on two industrial multihole melt blowing nozzle designs used for hot-melt adhesive applications for hygiene products, in order to study two defects that influence the quality of the adhesive bond: fibre breakup, resulting in contamination, and the presence of shots, undesirable lumps that end up in the finished product. To this end, the fibre dynamics were captured at the nozzle exit region by using high-speed imaging. From the results it was observed that die drool is the main source of shot formation, while fibre breakup occurs as a result of applying a sufficiently large force in the direction perpendicular to the fibre. In addition, three dimensionless parameters were defined, the first two being the air-polymer flux ratio and the dimensionless temperature ratio, both of which represent the operating conditions, and the remaining one being the force ratio, which represents the nozzle geometry. The effect of these parameters on fibre breakup and shot formation was studied and the results indicate that both the operating conditions and the nozzle geometry were responsible for the onset of the fibre breakup and for the formation of shots. More precisely, both defects turned out to be dominated by the air-polymer flux ratio and the air tilt angle. The results that emerge from this study are useful for the enhancement of industrial melt blowing nozzles.

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“…Because shear flow was efficient to enhance the crystallization kinetics [23, 24], there might be an annual contour of microcrystallization gradient structure in the fiber cross‐section (see Fig. 5), similar with the sheath‐core structure in the literature [18]. It seemed that this kind of microstructure phenomenon in melt‐blown fibers was not seen at ordinary times.…”

Section: Theoreticalmentioning

confidence: 68%

“…In 1998, Shambaugh et al [18] stated that there existed a radial variation in molecular weight in melt‐blown fibers. They pointed out that this difference contributed to the sheath‐core structure in molecular weight, caused by polymer degradation (thermooxidation reaction of oxygen with the polymer) in the fibers.…”

Section: Introductionmentioning

confidence: 99%

Shear flow of molten polymer in melt blowing

Xin

Wang

2012

Polymer Engineering & Sci

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Besides the air flow field, the flow field of molten polymer plays a key role in fiber formation in the melt‐blowing (MB) process. In this article, the flow field of molten polymer was discussed, and its effects on the fiber microstructures were studied through theory and experiments. First, this field was supposed to be a kind of shear flow field. Two equations were introduced and solved. Then, analyzing the solutions combining with the actual melt‐blown practice, we concluded that the distribution profile of this flow field was a series of inverse parabolic in the course of the polymer stream attenuating. Further inferring from this flow pattern, we could also assume that there could have been a novel cross‐sectional microstructures in the melt‐blown fibers. Finally, the comparison experiments concerning the MB and its fibers were designed and carried out. The results indicated that the shear flow field could be qualitatively described by the equations, and the assumptions about the microstructures are basically in agreement with the experimental results. POLYM. ENG. SCI., 2012. © 2012 Society of Plastics Engineers

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Sheath−Core Differences Caused by Rapid Thermoxidation during Melt Blowing of Fibers

Cited by 5 publications

References 14 publications

Study of Meltblown Structures Formed by Robotic and Meltblowing Integrated System: Impact of Process Parameters on Fiber Diameter Distributions

Study of Meltblown Structures Formed by Robotic and Meltblowing Integrated System: Impact of Process Parameters on Fiber Diameter Distributions

Experimental study of fibre breakup and shot formation in melt blowing nozzle designs

Shear flow of molten polymer in melt blowing

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