Fundamentals of Textile & Classification ofTextile FiberFlow chart of synthetic process of MMF & Classification of MMFFiber FormsDenier, Filament denier, Cotton count ,Tex & ConversionMan made fiber technology & Regenerated & Synthetic fiberBasic characteristics of MMFInfluence of chemical structure on propertiesFundamental of MMF ProductionGeneral principle of Spinning process & Spinning of polymerComparative Feature of Melt, Dry, Wet SpinningManufacture ofViscose Rayon & Factors affecting the quality ofViscose & Manufacturing process flow chart Flow chart of lyocell process & Schematic diagram of Lyocell &Cuprammonium Rayon
IntroductionA textile is flexible material consisting of network ofnatural or artificial fiber often referred to as thread or yarn.fibers is defined as unit of matter characterized byflexibility, fineness, and a high ratio of length to thickness.Fabric refers to any material made through weaving,knitting, crocheting, or bonding .Apparel is anything that one puts on ones body.Clothing,shoes, hats, globes, & scarves are example of apparel items
1. Naturally occurring fibers of vegetable origin.2. Naturally occurring fibers of animal origin.3. Regenerated man-made fibers which use somenaturally occurring substance as the raw material.4. Synthetic man-made fibers which use syntheticorganic compounds as raw material.5. Mineral fibers which are entirely inorganic.
Synthetic fiber has beginning with chemistry;A media is developed and filtered under pressure;It is then extruded into continuous filaments;The filaments are allowed to solidify ;They are then stretched;A finishing solution is then applied;The bundle of filament is then crimped;The final step before packaging and shipping is:Cutting the fiber bundle into staple length
Man made fiber can be classified intothree classes:1).Those made from natural polymers2).Those made from synthetic polymers3).Those made from inorganic materials
Man madefiberOrganic InorganicBy transformationnatural polymerFrom syntheticpolymerViscoseCuproLyocellAcetateTriacetateModalAlginateElastodienePolyesterPolyamidePolypropylenePolyvinylPolyethyleneElastaneModacrylicAramidAcrylicCarbonCeramicGlassMetal
Continuous Filament yarnSpun or staple yarnTowMono filament
The coarseness of yarn or filament is usually gaugedas denier. Denier is a unit of measure for the linearmass density of fibers.The denier of a yarn is the weight in grams oflength of 9000 meters of that yarn.i.e- If 9000 meters of yarn weigh 100 grams-theyarn is said to be 100 denier.The term micro denier is used to describe filaments thatweigh less than one gram per 9000 meter length
Filament denier only relates to a single filament (D.P.F is commonlyknown as denier per filament) Total denier relates to a yarn, anagglomeration of filaments.D.P.F=Total denier/Quantity of uniform filamentsIf a yarn of 100 denier is composed of either 20 or 60 filaments, thenthe filament denier will be:For 20 filaments yarn,D.P.F = 100/20 = 5 denier- coarse filamentFor 60 filaments yarn,D.P.F = 100/60 = 1.7denier-fine filament
The yarn numbering system based on length & weightoriginally used for the cotton yarns & now employed for moststaple yarns spun on the cotton or short staple system.The number of 840-yards in 1 lb is known as cotton count.Under this system, the higher the number, the finer is theyarn.Tex is the unit measure for the linear mass density of fibers &is defined as the mass in grams per 1000 meters.Tex is morelikely to be used in Canada & Europe.While denier remainsmore common in united states.The unit code is “tex”.The most commonly used unit isactually the decitex, abbreviated dtex, which is the mass ingrams per 10,00 meters.
Then mathematically,1000m filament will weight 1 gram, which is also 9denierAgain we know, if 1000m filaments weight 1 gram, it issaid to be 1TexSo from the ‘linear mass density of fibers’ point of view9 denier = 1.0000 tex1 denier = 0.1111 texFrom above T= D × 0.1111Or T = (5315/C) 0.1111 Or T = 590.5/COr T× C = 590.5C = 5315/D or D = 5315/CC× D = 5315
HOHHHOHOHHOHCH2OHHB. GlucoseHOHHOHOHHCH2OHHRepeating unit B. GlucoseHHHOHOHHOHCH2OHOHHCH2OHHHOOOHOHHOnCELLULOSE
WHAT ARE MAN MADE FIBER?A class name for various fibers (filaments) synthetically producedfrom fiber- forming substances.The first group, of which rayon and acetate are examples, areproduced by regenerating and modifying natural fiber- formingmaterial such as cellulose.The second group, frequently called synthetics and including suchfibers as nylon and polyester, are produced from syntheticchemicals.The third group, produce from inorganic materials, is known ascarbon, glass and ceramic fibers.
The man-made fibers, derived from naturally occurring polymers areknown as regenerated fibers. For instance rayon and acetate are madeof the same cellulose polymers that make up cotton. Example ofregenerated fibers is Viscose, Cupro, Acetate, Lyocell, Alginate, Modaletc.Synthetic fibers is the another group of man-made fibers. Syntheticfibers are made of polymers that do not occur naturally. They areproduced entirely in the chemical plant or laboratory, almost alwaysfrom by product of petroleum. Example of synthetic fibers is Polyester,Polyamide, Polyvinyl , Acrylic, Polyethylene etc. A high softening point Solubility or melting ability for spinning Adequate tensile strength A high modulus or stiffness
Figure: Cellulose based polymersWhen X represent hydrogen, the polymer is Glucose.The rayon fiber can be formed by converting the –OH groupsto xanthate groups(e.g.-OC(S) SNa .Cell-XanthateHHnCH2OXHHOXOXOXHSSNaCell-O-C
Substitution of –OH groups by acetyl groups (-OC(O)CH3), than the polymer iscalled acetate.Cell-OX + 2(Acetate groups) =Cell-AcetateCell-OX + 3(Acetate groups) = Cell-Tri-acetateOlefins(alkenes), a family of hydrocarbon compounds which are producedfrom the refining of petroleum and natural gas contains one double bondbetween two carbon atoms.The chemical formula can be represented asCH2=CHR, with R representing any of several possible atoms or groups ofatoms in the repeating unit of a polymer.The compound has the followingchemical structure as shown in the figure.CHCH2RnPolyolefinsWhen R represented as –CH3 group, then the polymer is calledPolypropylene.It has moderately high melting point (176°C) that can be melt spun intofiber useful for several types of clothing, upholstery, carpets and nonwoven fabrics.
When R is hydrogen the polymer is polyethylene.A relativelylow melting material(137°C) that finds uses as a fiber inindustrial application–e.g. non-woven fabrics- but not in most householdapplication.When R represents a cyano , or nitrite, group (-C= N),containing carbon and nitrogen linked by a triple bond. In thiscase the polymer obtained is polyacrylonitrial, an acrylicThat does not melt without decomposition and thereforemust be solution spun into fibers used in clothing, drapes,and carpets.It is observed from the structure variation that the methyland cyano groups in polypropylene and polyacrylonitrile raisemelting points.
Most synthetic and cellulosic manufactured fibers are created by“extrusion” forcing a thick, various liquid through the tiny holes of adevice called a spinning to form continuous filaments of semi-solidpolymer.In their initial state, the fiber-forming polymers are solids andtherefore must be first converted into a fluid state for extrusion.Thisis usually achieved by melting, if the polymers are thermoplasticsynthetics (i.e. ,they soften and melt when heated), or by dissolvedthem in a suitable solvent if they are non-thermoplastic cellulosic. Ifthey cannot be dissolve or melted directly, they must be chemicallytreated to form soluble or thermoplastic derivatives.Fundamentals of Man- made Fiber Production
The manufacturing of fibers from natural or synthetic polymer involves thefollowing technical operations:Preparation of spinning fluid from solid polymer or directly frommonomers.Spinning:• Extrusion of spinning fluid through spinnerets,• Emerging fluid jets into filaments of required thickness,• Solidification of polymer material,•And collection the obtained filaments on a suitable mechanical device (rotating bobbin, centrifuge, wind up package etc.)Mechanical, thermal and chemical treatment of the fibers to improvetheir properties.
There are typically three types of spinning for polymers- Melt, Dry and Wet.In melt spinning the fiber forming material is melted and extruded throughspinneret, and the jets harden into solid filaments as they cool on emergingfrom the spinneret, Nylon is a melt-spun fiber.In dry spinning the fiber forming is dissolve in a solvent before the solution isextruded. As the jets of the solution emerge from the spinneret, a stream ofhot air causes the solvent to evaporate from the spinning solution, leavingthe solid filament. Acetate is a dry spun by extruding acetone solution ofcellulose acetate into hot ho air.In wet spinning them solution of fiber forming material is extruded intocoagulating bath that causes the jets to harden as a result of physical orchemical changes.V iscose, for example of wet spun.
Features melt dry WetInvestment cost low High LowHazard Non-toxic Toxic(risk ofexpolsion)ToxicHeat of spinning High High LowSpinneret hole 2 to manythousand300-900 20,000-75,000Spinning speed 2500-3000ft/min2500-3000ft/min150-300 ft/min
Wood contains other substance like lignin, beside cellulose. So it ispurified, treated with caustic soda, which converts it into alkalicellulose, then treated with carbon disulphide, which converts it intosodium cellulose xanthate & then dissolved in dilute solution of causticsoda.The solution is then ripened & then spun into an acid coagulatingbath, which precipitate the cellulose in the form of a viscose filament.Cell-OH + NaOH Cell-O- Na+Cell-O- Na+ + CS2 Cell-O-C SS- Na+Cell-O-C H2SO4S- Na+S + Cell-OHCellulose, Soda cellulose, Sodium cellulose Xanthate, Regenerated Cellulose.
Preparation of the wood pulpConditioning of wood pulpSteeping (Formation of soda cellulose)Shredding (Cutting)AgeingChurning (Xanthation or sulphidising)Mixing (Dissolving)RipeningSpinningWind up/Cutting
LikeViscose, Cuprammonium Rayon is also a regenerated cellulose fiber.Cotton Linters are used as the source of cellulose for this rayon.Cuprammonium solutionAmmoniacalCopper Oxide solution, known as Cuprammonium Hydroxidesolution[Cu(NH3)4(OH)2] is obtained by pouring a solution of Ammonia inwater over Copper turnings, at 5 ͦC.A solution of Copper Sulphate (CuSO4.5H2O) is mixed with caustic soda toformCopper Hydroxide.CuSO4 + NaOH Cu(OH)2Purified and bleached cotton linters are added and stirred.The copper cellulose thus formed may be stored for a long time. The liquoris filtered off. The deaearated cellulose solution is ready for spinning.Cuprammonium cellulose solution is discharged from the spinneret into asolution of sulfuric acid in the form of relatively thick threads which aresubsequently stretched to very fine filaments by a rapid pull.
ViscoseAcetateCuproPropertiesFiberTensile strength(GPD)Moisture absorption Density(1.5-2.4) at dry(0.2-1.2) at wetAbsorb moisture at70 F & 65% Rh13%1.5 gm/cc.(1.1-1.3) at dry(0.65-0.75) at wetMoisture absorb6.5% at 65% Rh(1.7-2.3) at dry( 1.1-1.35) at wet12.5% understandard conditionThefilament areavailable in1.3 denierContinuousfilament 1.5-5.5 denier