TEST 1 Flashcards
what is pulp fiber?
short, fine, cellulose fibers
why are pulp fibers used?
they are inexpensive and have absorption properties
what is a composite?
2 different materials
what is a coform?
a fiber that goes through 2 functionally similar processes
why are nonwovens important in the medical field?
due to their barrier properties, they provide good protection while being lightweight
2 ways nonwovens are used in the composite industry
idk
why are nonwovens useful in roads and highways
to transport mositure, be a strong support, abrasion resistance, and resist cracking
what is the main challenge for the use of nonwovens in window treatments?
nonuniformity
why is polypropylene the most used fiber in nonwovens?
because it has a low density, you get more for the same amount of material
why are meltblown splittable being widely used in filters?
because we need different shapes and sizes to allow the filter to stop the particles. it gives the properties of 2 in 1.
5 desirable properties for hygiene applications
lightweight absorbent soft comfortable flexible
5 desirable properties for crop covers
lightweight air permeable water permeable uv resistance resistance to bugs and insects
3 reasons why nonwovens haven’t suffered as much as other industrys
capital requirements
low labor requirements
technology patents
how to make a low density abrasive pad
low density web needs adhesive with abrasive particles which can be sprayed or dipped, then we will use heat to cure and assist in particle web stability
5 properties used in nonwovens analysis
fiber orientation bond to bond distance mass nonuniformity number of crossovers pore size and shape
2 most important properties of nonwovens analysis
fiber orientation and mass nonuniformity
what is the break-up length
in hydroentangling, the water is no longer in a pencil like stream
3 main factors in hydroentangling and why are each important
water pressure, strong enough to entangle the fibers
energy transfer, make sure the fibers get entangled but don’t make big holes
and web support system bc the belt will make a negative image and it will affect the fiber properties
6 parts of the double reduced needle
crank superior rod taper intermediate rod active rod point
conduction
by touching something hot, calendar bonding
convection
heat transferred through air, thru air bonding
radiation
heat transferred by light, infrared
work
by rubbing 2 things together; ultrasonic
is cone up or cone down better to use under normal pressure
cone down because it maintains a steady stream longer
T/F: for spunbonding the main difference in in-house systems was the type of spinneret used
F
T/F: the melt blowing process makes continuous filaments with very fine deniers
F
T/F: Shrinking of nonwovens relieves stresses and removes distortions, but it also reduces dimensional stability
F
T/F: polymers used in melt blowing should have a melt flow index lower than those used in spun bonding
F
T/F: in collecting a spun bonded web on a drum it is necessary to slightly pre bond the web
T
T/F: in melt blown webs shots can occur either from heating the polymer too much or not heating it enough
T
T/F: splitting of nonwovens is used to cut wide farbics into smaller widths
F
T/F: for melt blowing if you wish to have finer fibers you should increase the specific output rate so that the polymer moves through the system faster
F
T/F: for spun bonding if you wish to have high basis weight and high speeds you must have multiple spin beams
T
T/F: creping of nonwovens will give increased basis weights
T
T/F: spun bond webs with random variations result from using multiple beams
F
T/F: in melt bloowing increasing the air gap will cause the fibers to cool more quickyl
F
T/F: two ways to keep particples inside of a web is to attach the particle to the fiber using adhesives or second use particles that are small than the fiber diameter
F
T/F: layered composites bonded by needle punching will have a fuzzy interface
T
T/F: mouting the spinneretter block in spunbonding requires the use of many small screws to that polymer flow is not impeded
F
T/F: extrusion coating marries a nonwoven with a film
T
meltblown vs spunbonded volume of air
meltblown: large Spunbonded:small
meltblown vs spunbonded temp of ari
meltblown: high temp spunbonded: room temp air
meltblown vs spunbonded where is drawing force applied
meltblown: die tip spunbond: attenuator
3 components of melt blown die assembly
polymer feed distribution, dye nosepiece, and air manifolds
how is medical blue made?
card web with tissue paper hydroentangled into the card web with a polyurethane coating/finishing
what fabric is now replacing medical blue and why
sms becasue it maintains all the absorption and barrier properties while also being breathebale
6 machine processing variables in melt blowing
polymer/die temp air temp die to collector distance collector speed polymer throughput air throughput
how to make a 3D needlepunched fabric with pockets of particles
lay down an air lay web, lay down particles, then lay down another layer of fabric and selectively needle punch to connect the certain parts of the web
3 reasons why nonwovens make good depth filters?
many layers of different constructions
different chemsitries in each layer
- differnet pore sizes
how do nonwoven cards differ from tradiational cards(9)
webs instead of sliver do not nees sliver elemtns randomizer rolls wider shorter faster more expensive makes higher loft webs extra safety measues
fiber factors that influence needling (4)
type of fiber
physical properties
geometric properties
surface and friction
fiber web factors that influence needling (5)
basis weight thickness closeness orientation of fibers opening of fibers
off line lamination sms (2)
spunbonded and melt blown are produced separately and calendered to form SMS fabrics
OR
spunbond fabrics are fed to the calender of the melt blown line
in line lamination sms
spunbond and melt blown webs are produced on the same forming belt, spun bond is forming omn the forming belt first and that is followed by melt blown which is then followed by another spunbond, this is then fed to the calender for bonding
multilayer structure for vacuum cleaner bag
Wet laid special filter
melt blown
carbon. (odor absorption layer)
fleece
