COMPOSITE YARNS & their APPLICATIONS AND

Friction spinning.

Group Members :

Tharanga A D (061054 E)Somasiri M R P (061051 R)Sathkoralage (0610nn n)Singhabahu (0610nn n)Tharmarajah E J(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 open-

end rotor spinning frame was developed. At two filament over-

feed 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

• Yarn tension under varying twist factorsContinued…

•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.

• 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 structureContinued…

a) Normal rotor-spun yarns, b) Composite yarns (OFR=0.97),c) Composite yarns (OFR=1.06).

•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.

• Effects of twist factor on yarn strength and elongationContinued…

•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…

• 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.

MAKING OF COMPOSITE SILK YARNS BY THROSTLE SPINNING FRAME.

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

• 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.

Continued…

CUT RESISTANT COMPOSITE YARNS

Continued…

• Under these category lot of products are available:Continued…

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.

• 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.

Continued…

•Furthermore, the doubled yarn is combined by twisting together two single yarns.

• The strength comparison Continued…

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.

Twin ˃ Core ˃ Doubled

• Comparison of the elongation

• Ey=ef/cos2α• It was found that the tendency to

increase is clearly due to the increase in the twist angle.

Continued…

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.

END OF PART 01

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