TANDEC RESEARCH
Welcome to the TANDEC Research Site at The University of Tennessee, Knoxville
Academia and Industry fostering new devlopments in non-wovens
Ecclesiastes 1:9
The thing that hath been, it is that which shall be; and that which is done is that which shall be done: and there is no new thing under the sun.
This Site Showcases our reasearch at TANDEC. Please scroll down for our featured article this month or use the links to the right to see other articles of interest.
Article Subjects-
Absorbency
Barrier
Properties
Web
Structure
Previous Articles
Research of Electrospinning at TANDEC by Peter Tsai
Progress in Meltblowing Thermoplastic Polyurethane by Larry Wadsworth
Development of
Bi-Component Meltblown Fiber Nonwovens and
Its Potential to Produce Submicron fibers by Christine Sun and Dong
Zhang
FIBER MOTION NEAR THE COLLECTOR DURING MELT BLOWING
By Professor Randall R.
Bresee
Professor, Department of Materials Science and Engineering
We have studied the commercial melt blowing
(MB) process for many years using 6-inch, 20-inch and 24-inch
MB lines at TANDEC. This work has substantially increased our
understanding of MB. In this note, we recap information about
fiber motion near the collector.
Web structure development during MB is dynamic,
beginning near the die and becoming fixed only when fibers
contact the collector and their motion ceases. Consequently,
fiber flow near the collector significantly influences web
structure. Fiber motion near the collector is influenced
predominantly by three things: airflow near the collector, movement of
the collector surface (collector speed) and fiber entanglement.
The following photograph shows typical fiber flow in a 9cm x 9cm area near a rotating drum collector (fiber flow is left-to-right); the “envelope” surrounding fiber flow is identified with white dashed lines. Fiber flow far (9cm) from the collector is only slightly divergent but divergence increases substantially near the collector (within 3cm).
Fiber Flow in a Horizontal MB Line with a Rotating Drum Collector.
Fiber flow is displaced toward the direction of
collector movement as a result of physical contact with the
collector surface. A leading segment of a fiber that contacts
the collector is physically transported by collector motion
and this movement influences the flow direction of trailing
segments of the same fiber as they approach the collector. This
is reasonable since collector speed easily exceeds fiber speed closer
than 3cm to the collector where laydown occurs and fiber speed
decreases to zero.
Fiber entanglement has a significant influence
on web structure and properties. Moving the collector closer
to the die reduces fiber entanglement for two different
reasons. First, it provides less time for fibers to contact
one another and become entangled before contacting the
collector. Second, it increases fiber flow divergence which increases
fiber separation in space and decreases the likelihood of fiber
entanglement.
More information about these topics can be
obtained from Dr. Bresee (rbresee@utk.edu)or
on-line (http://www.inda.org/subscrip/index.html)in
the following publication: Bresee, R.R. and Qureshi, U.A. “Fiber
Motion Near the Collector During Melt Blowing. Part I: General
Considerations,” International Nonwovens Journal, 11(2), 27-34
(Summer 2002).