Transcript Tire Polymers - The Chicago Rubber Group, Inc.

Polymers:
An
Overview
PRESENTED BY
JOHN M. LONG
JMLong Rubber Consultants, LLC
TO
Chicago Rubber Group
May 10, 2011
Natural Rubber
Natural Rubber
Cis- 1,4 polyisoprene
Natural rubber is composed of virtually
100% Cis-1,4 polyisoprene.
Natural Rubber
Rib Smoked Sheet
Produced from latex
Dried and smoked
Packaged in 75 or 220 lb. bales
Subject to crystallization
Heat treatment
Natural Rubber
Technically Specified Rubber (TSR)
Produced from air dried latex
Ground and washed
Dried and baled in 75 lb bales
Graded by dirt content
Heat treatment
Special grades made from latex
Natural Rubber
Used in application where high loads and
temperatures are encountered
Aircraft
OTR
Radial MT
Used for tack and green strength
Tend to go to the hot roll
Natural Rubber
Abrasion resistance lower than SBR/PBD in
passenger tire applications
Synthetic Polyisoprene
Cis-1,4 polyisoprene
Synthetic polyisoprene has from 92 to 98%
cis content.
Synthetic Polyisoprene
Lacks the non rubber constituents of Natural
Rubber
Proteins
Amines
Solution Polymerized
Stereo specific catalysts
Synthetic Polyisoprene
Augments Natural Rubber usage
Easier to mix
Does not have to be heat softened
More consistent than Natural Rubber
Poorer tack and green strength than Natural
Rubber
Styrene Butadiene Rubber
(SBR)
Styrene Butadiene Rubber
(SBR)
Emulsion Polymerized
Water and Soap
Chemicals to start and stop reaction
Coagulation with acid or salts
Cold (4 ºC) or Hot (50 ºC)
Styrene content normally 23.5%
Styrene randomly distributed
Cis, trans, vinyl content
Wide Viscosity ranges available
Styrene Butadiene Rubber
(SBR)
Emulsion Polymerized
Oil extended versions
Processing of high molecular wt. polymers
Black Masterbatches
With or without oil
Eliminates the need for extra mixing steps
Assures excellent carbon black dispersion
Styrene Butadiene Rubber
(SBR)
Emulsion Polymerized
Easy to mix and process
Tend to go to the hot roll
Highest strength when used with Carbon Black
or Silica
Widely used in tires
Treads w/ polybutadiene (wear and traction)
Sidewalls w/ polybutadiene and natural rubber
Carcass w/ natural rubber
Low cost
Styrene Butadiene Rubber
(SBR)
Solution Polymerized
Made by solution process
Stereo specific catalysts
Styrene insertion controllable
Cis, trans, vinyl ratio controllable
Oil extended versions available
Styrene Butadiene Rubber
(SBR)
Solution Polymerized
More difficult to process than emulsion SBR
Additional mixing
More die swell
They tend to go to the hot roll
More expensive than emulsion SBR
Used predominately in treads for low rolling
resistance passenger tires.
Polybutadiene
Polybutadiene
Solution Process using stereo specific catalyst
Normally 92-98% cis
Some polymers with high vinyl
Difficult to process by themselves
Poor green strength, die swell, bagging
Normally blended with SBR or Natural Rubber
Tend to go to the hot roll
Polybutadiene
Used in passenger tires
Treads
Improved abrasion resistance
Improved rolling resistance
Improved flex cracking resistance
High vinyl polybutadienes in low rolling resistance
compounds
Sidewalls
Improved flex fatigue resistance
Butyl
Butyl
Solution Polymerized
Low unsaturation (0.7 to 2.2%)
Mostly saturated backbone
Strong cure package needed
Used for Curing Bladders and Innertubes
Can be difficult to disperse fillers
Can be sticky on the mill
Tends to go to the COLD roll
Butyl
Will not co-cure with SBR, Natural, etc.
Will cause separations and failures if mixed into
unsaturated polymers.
Can be cured with sulfur or resin curing systems
Halogenated Butyl
Halogenated Butyl
Solution Polymerization
Halogenation of cement
Neutralization and stabalization
Can co-cure with unsaturated polymers
Processing
Mix temperatures over 290 ºF can cause
“carbon black scorch”
Do not mix with zinc oxide in first mixing pass
Halogenated Butyl
Processing (Continued)
Some AO’s and resins can pre cure halobutyls
Watch workaway materials
Halobutyl compounds tend to go to the COLD
roll
Halogenated Butyl
Used in
Innerliners (impermeability)
WSW, BSW, cover strips (Ozone resistance)
Innertubes (impermeability, heat resistance)
EPDM
EPDM Third Monomers
*
Polymerizable double bond
EPDM
Solution Polymerized
Third monomer activity
DCPD<Hexadiene<ENB
1.5 to 11% in polymers
8-11% used when blending with unsaturated
polymers.
Low unsaturation can give same problems as
butyl in blends with unsaturated polymers
EPDM
Ethylene
50-75 weight %
Processing
In tires usually blended with other polymers
Compounds process the same as the base
polymers the EPDM is blended with
Lower ethylene tend to mix easier
EPDM
Uses
White Sidewall, Cover strips, Black Sidewalls
because of outstanding ozone resistance
White Sidewall and Coverstrips
Blended with halobutyls and natural rubber and
possibly SBR
Black Sidewalls
Blended with natural rubber and polybutadiene
EPDM
Uses
Industrial Rubber Goods
Good high temperature resistance
Can be highly extended with fillers and oil for
reduced cost compounds
Can be compounded to give low compression set
Nitrile
Acrylonitrile/Butadiene (NBR)
Nitrile
Acrylonitrile/Butadiene (NBR)
Acrylonitrile/Butadiene ratios typically 18/82 to 45/55
Very good oil resistance, high strength
The higher the Acrylonitrile content the better the oil
resistance
Common polymer in industrial rubber goods
Gaskets
Shoe Soles
Belting
Hoses
V-belts
Nitrile
Acrylonitrile/Butadiene (NBR)
Sulfur curable
Conventional curatives
Some times used with blends
PVC
SBR (cost)
Need to use polar plasticizers such as esters
DBP,DOP,DOA
Emulsion polymerized
Nitrile
Acrylonitrile/Butadiene (NBR)
Also exists in the Hydrogenated version (HNBR)
Excellent high temperature resistance
Expensive
Usually peroxide cured for maximum performance
Chloroprene (Neoprene)
Emulsion polymerized
Approximately 88-92% trans
Chloroprene (Neoprene)
Emulsion polymerized
Approximately 88-92% trans
Chloroprene (Neoprene)
Chloroprene
Excellent oil resistance
High strength
Good abrasion resistance
Good weather resistance
Good chemical resistance
Chloroprene (Neoprene)
Uses
Wire and Cable
Hose
Belts (flat and v-belts)
Adhesives
Molded and extruded
Curing
Metal oxides ZnO MgO most common
Thioureas and/or organic accelerators thiurams or
guanadines
Chloroprene (Neoprene)
Curing
Sulfur is also used in compounds requiring a slow cure
rate
Polyurethane
Three Types
Liquids
Thermoplastic
Millable Gums
Production of Urethanes
Polyols reacted with a Diisocyanate to form
Prepolymers
Prepolymers are reacted with diamines to form
Polyurethane
Polyurethane
Properties
High strength
Abrasion resistance
Cut and tear strength
Ozone resistance
Poor when subjected to high temperature water
(hydrolysis)
Poor when subjected to high temperatures (melting)
Specialty Polymers
Polyacrylate rubber (ACM)
Ethylene-Acrylic Elastomers (AEM)
Chlorinated Polyethylene (CM)
Chorosulfonated Polyethylene (CSM)
Fluoroelastomer (FKM)
Silicone Elastomer (MQ,VMQ, PMQ, PVMQ,
FVMQ)
Oil vs Temperature Resistance
500
450
FKM
VMQ
400
FVMQ
350
AEM
300
ACM
EPDM
HNBR
CO/ECO
250
SBR
200
Chloroprene
NBR
150
100
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Summary
This has been a quick review of significant
polymers used in tires and industrial products.
If anyone would like to discuss any of these in
more detail please call me.
John Long
JMLong Rubber Consultants, LLC
2204 Donner St. NW
North Canton, OH 44720
Phone 330-244-9680
Fax 330-244-9684
Email [email protected]