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
1.
2.
3.
4.
5.
6.
7.
8.
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
DIFFERENT TYPES OF TYRES
TYRE COMPONENTS
1.
THE TYRE IS A COMPOSITE
OF A RELATIVELY LOW
STRENGTH, HIGH
ELONGATION RUBBER
MATRIX & A HIGH
STRENGTH, LOW
ELONGATION TIRE CORD.
2.
THE TYRE CORD GIVES THE
TIRE SHAPE, SIZE,
STABILITY, LOAD
CARRYING CAPACITY,
FATIGUE & BRUISE
RESISTANCE.
3.
TYRE CORDS ALSO AFFECT
IMPACT RESISTANCE, RIDE,
HANDLING, TREAD WEAR &
FUEL ECONOMY.
Overlay
Belt
Carcass
Bead
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
•
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
- THE WEIGHT IN GRAMS OF 9000 METERS;
- DECITEX IS WEIGHT IN GRAMS OF 10,000 METERS.
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
INTRODUCED
MATERIAL
COMMENTS
•
1890’s
Bead wire
Normal tensile
•
1900
Cotton
Staple fibers, NO treating
•
1936
Steel (Europe)
Normal tensile/copper plated
•
1938
Rayon
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
MATERIAL
COMMENTS
•
•
•
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 APPLICATIONINCLUDING TYRE
• OF DIFFERENT MATERIAL SUCH AS
NYLON, ARAMID, HYBRID
USAGE
APPLICATION
PASSENGER
RLT
OVERLAY
Nylon
Nylon
BELT
Steel
Steel
CARCASS
Polyester
Polyester
BEAD
Steel
Steel
CHIPPER/FLIPPER
Nylon
Nylon
USAGE
APPLICATION
AIRCRAFT FARM
OTR
RMT
OVERLAY
Nylon
n/a
Nylon
BELT
Nylon
Polyester
Steel/Nylon
Steel
CARCASS
Nylon
Nylon/Polyester Steel/Nylon
Steel
BEAD
Steel
Steel
Steel
Steel
CHIPPER/FLIPPER
Nylon
n/a
Nylon
Steel
n/a
FIBRE MANUFACTURING
–
• SPINNING
– SOLUTION SPINNING
– MELT SPINNING
• DRAWING
FIBRE
CHEMICAL
COMPOSITION
RAYON
•
Wood Pulp + NAOH
Wet Spinning
w/H2SO4
Alkali Cellulose
Shredded & Aged
Ripening
+ CS2
Cellulose Xanthate + NAOH
Slashing
RAYON
H
C
Viscose
OH
C
H
H
C
CH2 OH
H
C
OH
O
CH
O
NYLON
• NYLON 66
Adipic Acid + NH3
Cyclohexane + Air
Adipic Acid
Adiponitrile + H
Hexamethylene Diamine
Polymerization + Melt Spinning
H
N
( C H2
(
Nylon 66
6
H
O
N
C
O
( C H2
(
Nylon
Salt
4
C
POLY ESTER
• POLYESTER
Ethylene Glycol + DMT/TPA
Melt Spinning
PolyEthylene Terephthalate
Polymerization
(PET)
Solid State
O
H
H
C
C
H
H
O
C
O
C
O
ARAMID
• ARAMID
Terephthalate Acid
p-Phenylenediamine
p-phenylene terephthalomide
Polymerization
Wet Spinning
(aka ARAMID)
H
H
N
N
O
O
C
C
w/Sulfuric Acid
Common Trade Names
Twaron® & Kevlar®
FABRIC PRODUCTION
• TWISTING
•
•
WEAVING
PROCESSING
CONVERSION OF CORD TO FABRIC
• STEP 1: TWISTING
TWISTING
YARN
PLY TWIST
CORD TWIST
TYRE CORD
TWISTING
#
EXPLANATION
Linear density
of base yarn
(units: decitex)
1400 / 1 / 3, 315Z x 315S
# of yarns in
ply
Twist count & direction for cord
(units: turns per meter)
# plies in cord
PERFORMANCE WITHOUT TWIST
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
RADIANT
DRYERS
E15
E16 E17
E18
E19
E20 E21
RADIANT
DRYERS
F15
F16
F17
F18
F19
#2
PULL
ROLL
FLEXIBILZER
#1 PULL
ROLL
.....
LET OFF
....
F20
F21
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.
TEMPERATURE VS SHRINKAGE
DIP PICK UP VS ADHESION
EFFECT OF TIME AND TEMP
PURPOSE OF DIP
• Bond dissimilar materials
• Transfer stresses from high modulus fiber to
low modulus rubber
• Cushion fibers from fretting
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)
UNTREATED
FIBER
DIP UNIT
ADHESIVE / HEAT
TREATED FIBER
CURED RUBBER COMPOSITE
MECHANISM OF RFL DIP
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
RELATIVE (Polyester = 100)
TENACITY
200
150
NYLON
100
50
0
TENACITY, Load/Linear Density
RELATIVE (Polyester = 100)
CORD MODULAS
1000
800
NYLON
600
400
200
0
CORD TENSILE MODULUS
RELATIVE (Polyester = 100)
ADHESION
350
300
NYLON
250
200
150
100
50
0
WORK OF ADHESION
DURABILITY
(Polyester=100)
RELATIVE
300
250
NYLON
200
150
100
50
0
DURABILITY (Applied Cyclic Strain tension/compression)
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.