CE 435 -- Intoduction to Polymers1 Firestone Tires Parag Patel Joshua Pun Cory Robinson

CE 435 -- Intoduction to Polymers 1

Firestone TiresFirestone Tires

Parag Patel

Joshua Pun

Cory Robinson


OutlineOutline

IntroductionTire ProductionOverview of Tread Separation ProblemLegal MattersConclusion/Questions


IntroductionIntroduction

Charles Goodyear 1800 – 1860– 1821: Went into hardware business– 1833: Started making rubber goods– 1834: Failure in first rubber venture– 1837: Eliminated some of the rubber defects– 1838: Bought patent from partner– 1844: Discovered Vulcanization


Tire ProductionTire Production Statistics:

Source: http://www.rubbernews.com/subscriber/charts/global.html

Tire Sales % of Total Tire Sales % of Total

(Millions $) Corp. Sales (Millions $) Corp. Sales

Bridgestone Corp.

Tokyo, J apan

Michelin et Cie.

Clermont-Ferrand, France

Goodyear Tire & Rubber Co.

Akron, Ohio/USA

Continental A.G.

Hanover, Germany

Sumitomo Rubber Industries Ltd.

Kobe, J apan

Pirelli S.p.A.

Milan, Italy

Yokohama Rubber Co. Ltd.

Tokyo, J apan2,408.20 70% 2193.5 70%

2,725.20 40% 3005.8 49%

3,413.80 76% 3,750.00 75%

4,900.00 50% 4,334.00 58%

11,515.60 85% 11,311.00 85%

13,500.00 92% 12,916.30 93%

1999 1998

Co./Headquarters

13,500.00 74% 12,634.80 74%


Raw Materials Raw Materials

Fabric (steel, polyester, nylon, etc.)

Rubber (synthetic, natural, or blends)

Reinforcing Chemicals (silica, resins, etc.)

Anti-Degradant (Ozonants, paraffin waxes)

Adhesion Promoters (brass, cobalt salts)

Curatives (cure accelerators, activators, sulfur)

Processing Oils (Oils, Tackifiers, Softeners)


Processing & ProductionProcessing & Production

Mix Process Oils, Rubber, Reinforcers, Accelerators, & Anti-Degradants

Coatings– Fabric– Steel Belt

Bead



Processing & Production (con’t)Processing & Production (con’t)

Components taken to tire machine for assemble– Inner liner– Ply Fabric (two layers) – possible cause of

problem– Apexes– Chafer Strips– Steel Belts– Curing– Inspection



Chemistry of Tires - IntroductionChemistry of Tires - Introduction

Overview of Vulcanization ProcessDescription of Brass-on-Wire

Adhesion2nd Major Issue in Faulty Firestone

Tires


VulcanizationVulcanization

Process by which rubber is chemically crosslinked (e.g. disulfides)

Makes material stronger, elastic, resistant to solvents, and moderate heat/cold.

Rubber is heated in the presence of sulfur and accelerator.


PropertiesProperties

SourceSource: Mark, James E. Science and Technology of Rubber. Academic: San Diego, CA, 1994


Vulcanization (con’t)Vulcanization (con’t) Heat with and without accelerators

– WithoutWithout: 5 hrs @ 140 oC / 8 phr sulfur– WithWith: 1-3 min @ 140 oC / 0.5 phr sulfur

Main Considerations:– Size and type of object (thick walled -> longer curing time)– Compound vulcanizabliity and flowability– Type of vulcanization (mould vs. boiler)– Maximum vulcanization temperature of material or system– Removal of article from mould (higher temp, more difficult)


MechanismsMechanisms

SourceSource: Mark, James E. Science and Technology of Rubber. Academic: San Diego, CA, 1994


Brass-on-Wire AdhesionBrass-on-Wire Adhesion

Process by which brass (CuZn) deposited on steel belts

Important for proper metal/rubber adhesion

Care must be taken to prevent oxidation of both brass and steel


Brass-on-Wire AdhesionBrass-on-Wire Adhesion

Formation of Copper Sulfide Layer Rubber infiltration into porous CuS layer Prevent ZnS/FeS layers (not porous)


Faulty TiresFaulty Tires

Brass on Wire coatings must be strictly monitored.

Coated/Uncoated wire should be kept in environmentally controlled conditions.

Free from particulate matter. Employee accusations of improper

handling– Poor quality control– Used oxidized/improperly handled wire


Cause of ProblemCause of Problem

The Ford Motor Company

-size of the Ford Explorer

-recommended tire pressure too lowDrivers of the Vehicles

-improper maintenance of tires

-wear and tear


Legal MattersLegal Matters

Both Firestone and Ford are in an ongoing battle with the public

Bridgestone/Firestone Position

-taken the responsibility for faulty design

-initiated world wide recall

-offered free replacements

-still believe blame should not wholly be on them


Legal Matters (con’t)Legal Matters (con’t)

Ford Motors Corporation’s Position

-stands by their design of Ford Explorers

-changed recommended tire pressurePlaintiff’s Position

-continue to file lawsuits

-boycott product manufactured by Ford and Firestone


Conclusions & Q/AConclusions & Q/A

Firestone liability in poor quality control & tread design

Ford maintains 26 psi sufficient, but has changed target to 30-35 psi.

Questions

Documents

CE 435 -- Intoduction to Polymers1 Firestone Tires Parag Patel Joshua Pun Cory Robinson