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FIBRE REINFORCEMENT . SRINI. TOPICS. Introduction History Of Tire Reinforcing Materials Current Reinforcement Line-up Fibre Manufacturing Processes Spinning / Drawing Fabric Production Twisting/weaving Processing Fibre Adhesives Property Comparison of different fabrics Summary .
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FIBRE REINFORCEMENT SRINI
TOPICS • Introduction • History Of Tire Reinforcing Materials • Current Reinforcement Line-up • Fibre Manufacturing Processes • Spinning / Drawing • Fabric Production • Twisting/weaving • Processing • Fibre Adhesives • Property Comparison of different fabrics • Summary
FUNCTIONS OF A TYRE • Provide load-carrying capacity • Provide cushioning • Transmit driving and braking torque • Produce cornering force • Provide dimensional stability • Resist abrasion • Provide steering response • Be durable & safe
Overlay Belt Carcass Bead TYRE COMPONENTS • THE TYRE IS A COMPOSITE OF A RELATIVELY LOW STRENGTH, HIGH ELONGATION RUBBER MATRIX & A HIGH STRENGTH, LOW ELONGATION TIRE CORD. • THE TYRE CORD GIVES THE TIRE SHAPE, SIZE, STABILITY, LOAD CARRYING CAPACITY, FATIGUE & BRUISE RESISTANCE. • TYRE CORDS ALSO AFFECT IMPACT RESISTANCE, RIDE, HANDLING, TREAD WEAR & FUEL ECONOMY.
COMPONENTS AND THEIR FUNCTIONS-1 • OVERLAY: • Placed on top of belt, often called cap ply, used to further improve crown area durability and high speed performance. • BELT/BREAKER: • Belts have lower angle than plies, provide tread area stiffness for improved tread wear & provide protection from foreign objects (e.g. rocks). Breakers have nearly the same angle as the plies and do not restrict the carcass plies, but provide crown area durability. • CARCASS: • Extending from bead-to-bead, often called ply, primary reinforcing & strength member of the tire.
COMPONENTS AND THEIR FUNCTIONS-2 • BEAD: • Multiple strands of wire, rubber coated & formed into extensible hoops, anchors ply & tire to the rim, also provides bulk & stiffness (in the bead area) to eliminate tire movement on the rim. • FLIPPER: • Provides a barrier between the ply and bead to prevent ply erosion • CHIPPER: • Provides lower bead-area stiffness to absorb deflection, and reduce chaffing
FIBER TERMINOLOGY-1 • FILAMENT • SMALLEST TEXTILE COMPONENT. A NEAR MICROSCOPIC, HAIRLIKE SUBSTANCE THAT MAY BE NATURAL OR SYNTHETIC. • YARN • - A CONTINUOUS STRAND SPUN FROM A GROUP OF NATURAL OR SYNTHETIC STAPLE FIBERS, OR FILAMENTS. • PLY • - ALL YARNS ARE SINGLE PLY, UNLESS TWISTED WITH ANOTHER YARN. - 2-PLY IF TWO YARNS ARE TWISTED TOGETHER AND 3-PLY IF THREE ARE TWISTED TOGETHER. - PLIED YARNS ARE USED TO MAKE YARNS STRONGER.
FIBER TERMINOLOGY-2 • TIRE CORD • - THE PRODUCT FORMED BY TWISTING TOGETHER TWO OR MORE PLIED YARNS. • WARP • - THE LENGTHWISE, VERTICLE CORDS CARRIED OVER AND UNDER THE WEFT. • WEFT • - ALSO CALLED FILL OR PICKS. THE LENGTHWISE, SELVAGE TO SELVAGE HORIZONTAL, YARNS CARRIED OVER AND UNDER THE WARP. - USED TO HOLD FABRIC TOGETHER THROUGH SUBSEQUENT PROCESSING OPERATIONS.
FIBER TERMINOLOGY-3 • DENIER/DECITEX • - TERM FOR THE LINEAR DENSITY(MASS PER UNIT LENGTH) OF A TEXTILE MATERIAL. • DENIER - THE WEIGHT IN GRAMS OF 9000 METERS; - DECITEX IS WEIGHT IN GRAMS OF 10,000 METERS. • TWIST • - THE NUMBER OF TURNS ABOUT ITS AXIS PER UNIT LENGTH OF A YARN OR OTHER TEXTILE STRAND. • CORD STRENGTH (Tenacity) • - ULTIMATE TENSILE LOAD OR FORCE REQUIRED FOR RUPTURE. • - FREQUENTLY , TIRE CORD STRENGTH IS EXPRESSED IN TERMS OF CENTINEWTONS PER TEX -CALLED TENACITY. • -THE FORMULA FOR TENACITY IS = ( BREAK STRENGTH(N) /(DECITEX)*1000 = cN/TEX
FIBER TERMINOLOGY-4 • CARCASS STRENGTH • - CARCASS STRENGTH IS A FUNCTION OF CORD STRENGTH, CORD COUNT ( ENDS PER INCH -EPI ) AND NUMBER OF PLIES - CARCASS STRENGTH = ( CORD STRENGTH * CORD COUNT * NUMBER OF PLIES ) • RIVET • - SPACE AVAILABLE BETWEEN TWO ADJIOINING CORDS FOR GUM TO FILL- ALSO REFFERED AS FILL GUM SPACE.. • - FORMULA IS - 1 - (ENDS PER INCH X CORD GAUGE) / ENDS PER INCH
HISTORY INTRODUCEDMATERIALCOMMENTS • 1890’s Bead wire Normal tensile • 1900 Cotton Staple fibers, NO treating • 1936 Steel (Europe) Normal tensile/copper plated • 1938Rayon Tension treating w/simple RFL • 1947 Nylon 6, 66 Treating w/modified RFL • 1955 Steel (USA) Normal tensile/brass plating • 1962 Polyester Treating w/modified RFL
HISTORY DATE MATERIALCOMMENTS • 1966 Fiberglass Treating w/simple RFL • 1974 Aramid Heat treat w/special RFL • 1982 HMLS PET 3T treating w /epoxy-based RFL • 1986 HT Steel/bead wire High tensile w/brass plating • 1992 ST Steel Super tensile w/brass plating • 1998 UT Steel Ultra tensile w/brass plating
New development -HYBRID • HYBRID FABRIC- SOME EXAMPLES • PET/NYLON • ARAMID/NYLON
SINGLE END CORD • SINGLE CORDS DIPPED TREATED • USED IN VARIOUS APPLICATION-INCLUDING TYRE • OF DIFFERENT MATERIAL SUCH AS NYLON, ARAMID, HYBRID
USAGE APPLICATIONPASSENGERRLT OVERLAY Nylon Nylon BELT Steel Steel CARCASS Polyester Polyester BEAD Steel Steel CHIPPER/FLIPPER Nylon Nylon
USAGE APPLICATIONAIRCRAFTFARMOTRRMT OVERLAY Nylon n/a Nylon n/a BELT Nylon Polyester Steel/Nylon Steel CARCASS Nylon Nylon/Polyester Steel/Nylon Steel BEAD Steel SteelSteelSteel CHIPPER/FLIPPER Nylon n/a Nylon Steel
FIBRE MANUFACTURING • SPINNING • SOLUTION SPINNING • MELT SPINNING • DRAWING
FIBRE CHEMICAL COMPOSITION
Wood Pulp +NAOH Shredded & Aged + CS2 Cellulose Xanthate + NAOH RAYON Ripening Wet Spinning w/H2SO4 Alkali Cellulose Slashing RAYON Viscose
Cyclohexane + Air NYLON • NYLON 66 Adipic Acid + NH3 Adiponitrile + H Adipic Acid Hexamethylene Diamine Polymerization + Melt Spinning Nylon Salt Nylon 66
POLY ESTER • POLYESTER Ethylene Glycol + DMT/TPA Melt Spinning PolyEthylene Terephthalate (PET) Polymerization Solid State
ARAMID • ARAMID Terephthalate Acid p-Phenylenediamine p-phenylene terephthalomide (aka ARAMID) Polymerization Wet Spinning w/Sulfuric Acid Common Trade Names Twaron® & Kevlar®
FABRIC PRODUCTION • TWISTING • WEAVING • PROCESSING
CONVERSION OF CORD TO FABRIC • STEP 1: TWISTING
YARN PLY TWIST CORD TWIST TWISTING
TWISTING # EXPLANATION Linear density of base yarn (units: decitex) 1400 / 1 / 3, 315Z x 315S Twist count & direction for cord (units: turns per meter) # of yarns in ply # plies in cord
EFFECT OF TWISTING • Improves bundle integrity (holds filaments together) • Combines two or more yarns • Increases Durability & Elongation • Decreases Tensile Strength & Modulus
WEAVING • The twisted cords lie in the machine direction, while the fill yarn is woven across the warp cords. • Provides means to interlace the twisted cords with filling yarns to form a woven fabric.
DIP PROCESSING Application of adhesive Enhance the physical properties of the fabric Stabilize the fabric for subsequent plant application Equalize differences between yarn sources
DIPPING PROCESS • APPLICATION OF ADHESIVE & TREATMENT OF FABRIC UNDER CONTROLLED CONDITIONS • TIME • TEMPERATURE • TENSION • DIFFERENCES RESULTING FROM SOURCE OF SUPPLY & MILL PRODUCTION VARIANCES ARE REDUCED • ADHESION • TENSILE PROPERTIES • THERMAL STABILITY • DURABILITY • FABRIC PROCESSING IMPARTS ABOVE CHARACTERISTICS BY CONTROLLING THE PHYSICAL STATE OF FIBRE • AMORPHOUS AREAS ARE PLASTICIZED BY MOISTURE & HEAT • TENSION IS APPLIED TO CREATE LINEAR ORIENTATION ALONG THE FIBER AXIS • TIME, TEMPERATURE & TENSION RELATIONSHIPS ARE THUS CRITICAL.
DIP UNIT MULTI STAGE DIP UNIT
DIPPING PROCES • EACH FIBRE TYPE & CORD CONSTRUCTION REQUIRES A UNIQUE PROCESS • SPEED DIFFERENTIAL, BETWEEN PULL ROLLS, PROVIDE SPECIFIED STRETCH FOR EACH ZONE. • HIGH TEMPERATURES REQUIRED TO ACTIVATE THE ADHESIVE & ESTABLISH DESIRED CORD PROPERTIES • MULTIPLE ZONE PROCESS REQD FOR DOUBLE DIP SYSTEM FOR FIBERS SUCH A POLYESTER, NYLON & ARAMID.
PURPOSE OF DIP • Bond dissimilar materials • Transfer stresses from high modulus fiber to low modulus rubber • Cushion fibers from fretting
UNTREATED ADHESIVE / HEAT CURED RUBBER COMPOSITE FIBER TREATED FIBER DIP UNIT SIMPLE DISPLAY • Wide array of compositions and application techniques available for fiber adhesives • Fiber type, end use and production requirements define limits to design • Coated fiber form (yarn, cord, or fabric) • Mechanical requirements (coating thickness, penetration, flexibility) • Chemical requirements (bonding to fiber and rubber matrix) • Service requirements (temperature, fatigue, age)
DIP ON PLY ESTER • Polyester fiber has weaker interaction with RFL adhesives than nylon or rayon • Hydrogen bonding much weaker with polyester • Energetics unfavorable for RF resin/polyester interaction • Epoxy resins applied to fiber or combined with RFL adhesive to provide adhesion • Epoxy resin selected for best compatibility with fiber • Resin components in RFL adhesive bond with epoxy
TENACITY NYLON FIBERGLASS POLYESTER ARAMID
CORD MODULAS ARAMID NYLON FIBERGLASS POLYESTER
ADHESION NYLON ARAMID FIBERGLASS POLYESTER
DURABILITY NYLON FIBERGLASS ARAMID POLYESTER
SUMMARY THE DEGREE OF FREEDOM AVAILABLE TO TIRE ENGINEER IN DESIGNING A TIRE COMPOSITE INCLUDE: 1. CHOICE OF A MULTITUDE OF CORD MATERIALS (RAYON, NYLON, POLYESTER, FIBERGLASS, ARAMID ETC) 2. AN ARRAY OF CORD CONSTRUCTIONS- e g 2-ply, 3-ply etc. 3. CORD TWIST LEVEL (e g 315Zx315S, 394Zx394S , etc.), balance vs. unbalanced etc. 4. VARIETY OF LINEAR DENSITIES 5. SELECTION OF RIVET AND NUMBER OF REINFORCEMENT LAYERS FOR VARIOUS COMPONENTS e g # OF PLIES - 10 Ply Actual , # OF BELTS, CHIPPERS, EPI COUNT etc.
SUMMARY SELECTION OF REINFORCMENT MATERIAL/CONSTRUCTION KEY TO OPTIMIZING IN-TIRE COMPOSITE PERFORMANCE.