Polymers: An Overview

1. Polymers: AnOverview PRESENTED BY JOHN M. LONG JMLong Rubber Consultants, LLC TO Chicago Rubber Group May 10, 2011

2. Natural Rubber Natural Rubber Cis- 1,4 polyisoprene Natural rubber is composed of virtually 100% Cis-1,4 polyisoprene.

3. Natural Rubber Rib Smoked Sheet Produced from latex Dried and smoked Packaged in 75 or 220 lb. bales Subject to crystallization Heat treatment

4. 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

5. 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

6. Natural Rubber Abrasion resistance lower than SBR/PBD in passenger tire applications

7. Synthetic Polyisoprene Cis-1,4 polyisoprene Synthetic polyisoprene has from 92 to 98% cis content.

8. Synthetic Polyisoprene Lacks the non rubber constituents of Natural Rubber Proteins Amines Solution Polymerized Stereo specific catalysts

9. 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

10. Styrene Butadiene Rubber (SBR)

11. 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

12. 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

13. 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

14. 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

15. 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.

16. Polybutadiene

17. 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

18. 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

19. Butyl

20. 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

21. 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

22. Halogenated Butyl

23. 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

24. 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

25. Halogenated Butyl Used in Innerliners (impermeability) WSW, BSW, cover strips (Ozone resistance) Innertubes (impermeability, heat resistance)

26. EPDM

27. EPDM Third Monomers * Polymerizable double bond

28. 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

29. 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

30. 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

31. 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

32. Nitrile Acrylonitrile/Butadiene (NBR)

33. 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

34. 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

35. Nitrile Acrylonitrile/Butadiene (NBR) Also exists in the Hydrogenated version (HNBR) Excellent high temperature resistance Expensive Usually peroxide cured for maximum performance

36. Chloroprene (Neoprene) Emulsion polymerized Approximately 88-92% trans

37. Chloroprene (Neoprene) Emulsion polymerized Approximately 88-92% trans

38. Chloroprene (Neoprene) Chloroprene Excellent oil resistance High strength Good abrasion resistance Good weather resistance Good chemical resistance

39. 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

40. Chloroprene (Neoprene) Curing Sulfur is also used in compounds requiring a slow cure rate

41. 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

42. 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)

43. Specialty Polymers Polyacrylate rubber (ACM) Ethylene-Acrylic Elastomers (AEM) Chlorinated Polyethylene (CM) Chorosulfonated Polyethylene (CSM) Fluoroelastomer (FKM) Silicone Elastomer (MQ,VMQ, PMQ, PVMQ, FVMQ)

44. Oil vs Temperature Resistance

45. 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 JMLongRC@NEO.RR.COM