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Transcript
COMPOSITE YARNS &
their APPLICATIONS AND
Friction spinning.
Group Members :
Tharanga A D
Somasiri M R P
Sathkoralage
Singhabahu
Tharmarajah E J
(061054 E)
(061051 R)
(0610nn n)
(0610nn n)
(061055 H)
Part 01
composite yarns & their
applications
WHAT IS A COMPOSITE YARN ?
• Staple (cotton or wool) + Filament (?)
• Filament can be:
– bonded to staple fiber ,
– wrapped with staple fiber ,
– wrapped around staple fiber
• Good for “technical” uses
• Posses the properties of both yarns.
Continued…
• Principal advantage of composite materials reside in the
possibility of combining physical properties of the constituents
to obtain new structural or functional properties.
• Composite materials appeared very early in human technology,
the “structural” properties of straw were combined with a clay
matrix to produce the first construction material and, more
recently, steel reinforcement opened the way to the
ferroconcrete that is the last century dominant material in civil
engineering.
PROPERTIES OF COMPOSITE YARNS.
• Relative light weight.
• Higher strength / stiffness
• Corrosion resistance and heat resistance (compared to metal)
• High performance
• Higher cost
• labor intensive
• Time consumed
• Mainly low production speeds
MANUFACTURING PROCESSES
• Composite yarns can be produced by many kinds of machines
and processes, such as ring, friction, and air-jet spinning, in
which the ring spinning process is more commonly used
• Several manufacturing processes are also available
- compression mold (SMC, BMC, DMC),
- injection mold
- liquid mold (RTM, SRIM)
• A recent development is combination of fibres made from
thermoplastic matrix(co-mingled glass fibres) resins with
conventional reinforcement fibres.
Continued…
- Thermoplastic is used because of the easy processing and the
less production cost. Also no cross links occur when heated.
- No need of controlling resin separately.
- Relatively complex structures with low price
ROTOR-SPUN COMPOSITE YARNS
• Rotor spinning has been adopted worldwide at present. Its main
advantages over ring spinning are:
– High yarn out put rates
– Reduced production costs
– Increased bulkiness
– Improved evenness
• However, the relatively low breaking strength and wrapper fibres
of yarn surface are still matters of concern. These disadvantages
may be improved by combining staple fibres with a continuous
filament yarn in the rotor spinning process.
Continued…
• Researchers show that the different types of yarns can be
produced by rotor spinning. For example “Cheng” reported a
method for making cover-spun yarns on an open-end rotor
spinning frame.
•
In one research, a composite yarn spinning system that
produces different kinds of composite yarns on a modified openend rotor spinning frame was developed. At two filament overfeed ratios, different kinds of rotor-spun composite yarns were
produced under varying twisting factors. The yarn tensions were
measured, and the effects of twist factors on the structure and
properties of composite yarns were investigated.
Continued…
The filament is passed
through the filament guide
tube and drawn into the
rotor freely by suction, in
which the filament yarn was
combined with the staple
fibre strand to form the
composite yarn.
•The yarn parameters are vary with the
spinning parameters and other properties.
Specially the factors are affected with the twist
factor
Continued…
• Yarn tension under varying twist factors
•While the yarn twist factors increase, both
the tensions of the filament and composite
yarns have a tendency to increase, and the
composite yarn tension is higher than the
filament tension.
•The tension of normal rotor-spun yarns
increases with increasing twist factors .
a) OFR=0.97, b) OFR=1.06.
Continued…
• Comparing Figure (a) with (b) in Figure 2, both the tensions of
the filament and composite yarns at the filament over-feed ratio
of 0.97 are higher than that at the filament over-feed ratio of
1.06. The filament over-feed ratio decreases, i.e. the filament
feed speed decreases gradually under the constant take-up
speed, so the filament tension increases. The composite yarn
tension will increase with increasing filament tension.
Continued…
• Effects of twist factor on yarn morphology and structure
•While the yarn twist factors increase the
helical angle of the polyester filament in the
composite yarns increases, the thread pitch
decreases, and the filaments have a tendency
to lie near the inner layer of the composite
yarn.
•When the filament tension increases the
filament yarn tends to lie along the axis of the
composite yarn near the centre as a core, and
can be covered by the staple fibre strand. In
the case of OFR=0.97, the polyester filament
tends to be located near the centre of the
composite yarn.
a) Normal rotor-spun yarns,
b) Composite yarns (OFR=0.97),
c) Composite yarns (OFR=1.06).
Continued…
• Effects of twist factor on yarn strength and elongation
•In the case of OFR=1.06, the filament tension
is relatively low, so the filament yarn wraps
over the staple fibre strand and follows a
helical path. As the filament tension increases
with increasing twist factors, the wrapping
action of the filament yarn is greater and the
yarn structure becomes tighter and more
uniform, so the inter-fibre cohesive forces
increase and the breaking strength of
composite yarns tends to increase also.
Continued…
MAKING OF COMPOSITE SILK YARNS BY THROSTLE
SPINNING FRAME.
• Throstle yarn is made of waste fibres, such as waste cotton and
bourrete silk, using the throstle spinning frame.
• It is soft to handle, has an irregular thikness, a low twist and
courser yarn count.
• By making a composite yarns, the properties can be improved.
Continued…
BUNDLED COMPOSITE CABLES
• Superior Essex offers multiple configurations of skip-wrapped or
bundled riser-rated (CMR) composite cables to support common
drop configurations used in residential structured wiring
installations.
• These composite cables improve installation time and reduce
the chance of violating minimum bend radius of the cable.
• The individual components support many technologies,
including extended bandwidth satellite service, 1000BASE-T and
100BASE-TX ethernet and high definition TV signals
• This product is also available with an optical fiber cable.
Continued…
ELECTROSPUN CARBON NANOTUBE
REINFORCED NANOCOMPOSITE YARNS
• A new class of engineered nanomaterials with superior
properties has emerged due to the discovery of carbon
nanotubes (CNTs) by Iijima in 1991.
• Electrospinning is a process by which ultrafine fibers with
diameter on the nanometer length scale can be manufactured.
• Fibers are drawn using electrostatic forces from a polymer
solution. Fiber diameter may be adjusted by varying the electric
field strength and polymer solution concentration, whereas the
duration of electrospinning controls the thickness of the
deposited fibermat
Continued…
• A drum-tape electrospinning system has been developed in the
laboratory for the creation of continuous yarn from electrospun
nanofibers. The current study demonstrates the successful
creation of continuous yarn and characterizes the level of
dispersion
of
CNTs
in
the
polymermatrix,
the
surfacemorphology, and the mechanical properties of
nanocomposite yarns.
CUT RESISTANT COMPOSITE YARNS
Continued…
Continued…
• Under these category lot of products are available:
ELASTIC COMPOSITE YARNS
• Composite yarns have a filamentary core provided with at least one
elastic performance filament(spandex and/or a lastol filament) and
at least one inelastic control filament.
• The at least one inelastic control filament is most preferably formed
of a textured polymer or copolymer of a polyamide, a polyester, a
polyolefin and mixtures thereof.
• Preferably, the fibrous sheath is formed of synthetic and/or natural
staple fibers, most preferably staple cotton fibers.
• The elastic composite fibers find particular utility as a component
part of a woven textile fabric, especially as a stretch denim fabric,
which exhibits advantageous elastic recovery of at least about
95.0%
COMPOSITE SPUN SILK YARNS
•Twin spun yarns, core spun yarns and
doubled yarns can be made by
different spinning methods. Then the
mechanical properties of composite
yarns and fabrics varied according to
the kinds of combined fibers.
•In the spun silk ring spinning frame
which is shown in Figure, two rovings
are drafted on each drafting zone and
are then twisted together to form a
yarn. The drafting part is equipped
with an apron device for the short
staple fibers. This yarn is called the
twin spun yarn.
Continued…
• As shown in Figure, a single
yarn is used in the core,
tension is provided by a
magnet tensor applied to the
front roller to combine with a
roving as the skin layer, and
then they are twisted
together. This yarn is called
the core spun yarn.
•Furthermore, the doubled yarn is combined by twisting together
two single yarns.
• The strength comparison
Continued…
Twin ˃ Core ˃ Doubled
When the number of twisting times in the
same direction is increased in the making
of composite yarns, it brings about many
twists in the yarn. It is known that as yarn
twist is increased, yarn strength rises to a
maximum value at some optimum twist
and then falls. The tensile behavior of
twisted staple yarns can be explained by
the effects of fiber obliquity with respect
to the yarn axis combined with the effects
of fiber slippage (Bogdan, 1956).
Therefore, it is found that the tendency to
decrease is clearly due to the effects of
fiber
obliquity
in
the
yarn.
•Comparison of the elongation
Continued…
• Ey=ef/cos2α
• It was found that the tendency to
increase is clearly due to the
increase in the twist angle.
ELECTRICALLY CONDUCTIVE ELASTIC
COMPOSITE YARN
• This is an electrically conductive elastic composite yarn having
an elastic member that is surrounded by at least one conductive
covering filament.
• The conductive covering filament has a length that is greater
than the drafted length of the elastic member such that
substantially all of an elongating stress imposed on the
composite yarn is carried by the elastic member.
• The elastic composite yarn may further include an optional
stress-bearing member surrounding the elastic member and the
conductive covering filament.
COMPOSITE YARN HAVING A SPANDEX CORE
AND A TEXTURIZED THERMOPLASTIC COVERING
• A method of manufacturing a composite yarn and composite yarn
produced thereby in which a spandex yarn is fed to an air entangling or
covering jet while being pre-elongated. Simultaneously, a multifilament
partially oriented thermoplastic yarn is fed to the yarn entangling or
covering jet while being partially or completely drawn to orient further or
completely the thermoplastic yarn.
• The thermoplastic and spandex yarns are fed through the yarn jet while
the filaments of the thermoplastic yarn are entangled to produce a
composite yarn with the spandex yarn as the core and the thermoplastic
yarn as a covering.
• The composite yarn is then fed through a false twister and false twisted
with the false twist being heat set in the thermoplastic yarn at a
temperature which does not adversely affect the spandex core to produce
an air entangled false twist texturized composite yarn.
• If not completely oriented when false twisted, the thermoplastic yarn is
further drawn to complete its orientation while being false twisted.
APPLICATIONS AND TRENDS
• Applications :
- Air craft manufacturing
- Automotive industry
- Civil engineering
- Biomedical
- Tissue engineering
• Trends :
- Cost minimizing
- performance development
- Nano-composite manufacturing.