1. TYPES OF TPEs & SELECTION CRITERIA FOR END APPLICATIONS
© ANOMITRA CHAKRAVARTY
KPS CONSULTANTS & IMPEX PVT. LTD.
ETDS CONFERENCE – DELHI, 5 th. MARCH 2014

2. Introduction
> Thermoplastic Elastomers (TPEs) combine the processing advantages of thermoplastics with the flexible, low-modulus properties of elastomers.
> Worldwide demand for TPEs is forecast to grow at 5.5 percent per annum to 5.8 million metric tons by 2017.
> Main growth - automotive components, consumer durables
roofing, adhesive / sealants / coatings, industrial etc.
> Main growth will come from Asia / Pacific
> Growth segments TPOs and TPVs

3. Some End Applications
Consumer: Toothbrush Handles, Running Shoes, Hand & Power Tools, Toys, Footwear, Home-ware etc.
Healthcare: Medical - Tubing, Stoppers, Bags & Bottles etc.
Electrical & Electronics: Cable & Wire Jacketing, Connectors & Plugs, Consumer Appliances etc.
Packaging: Cap Liners, Overmoulded Caps, Closures & Containers, Films & Sheets (modifiers)
Industrial: Hose & Tubing, Safety Equipment etc.
Building & Construction: Roofing Sheets, Window Sealing etc.
Automotive: Hose & Tubing, Interior, Window Sealing, Cable Jacketing, Under the Hood components etc.

4. TPE FAMALIES
1) Thermoplastic Polyolefin's (TPE-O or TPO)
2) Block Copolymers based on Styrene and Butadiene (TPE-S)
(e.g. SBS & SEBS)
3) Thermoplastic Vulcanizates (TPE-V or TPV)
4) Thermoplastic Polyester Elastomer (TPE-E)
Polyether Co-polyamides (TPE-A)
Thermoplastic Polyurethanes (TPE-U)

5. TPE-O Major properties
Thermoplastic Polyolefin's (TPE-O or TPO) are blends of PP with rubber, mainly ethylene propylene rubber (EPR), fillers and additives produced by compounding or by reacting in a sequence of reactors.
They can be produced to a hardness down to 75 Shore A. Lower hardness is difficult to achieve because the oil tends to migrate to the surface of the pellets or molded parts.
TPE-O Major properties
Good surface appearance
Elastomeric feel
Plasticizer free
Mechanical properties (high elongation at break and tear strength
Paint adhesion
Easy to color

6. Polyolefin Plastomers (POP) and Elastomers (POE) - bridge the gap between elastomers and thermoplastics, with rubber-like properties and the processability of plastic.
E.g. Affinity® and Versify® from Dow Chemical,
Exact® from Exxon Mobil Chemical
Elastamax® TPO (POE) from PolyOne
Exact plastomers are ethylene alpha olefin copolymers that are mainly used as polymer modifiers in flexible Packaging (enhance toughness, clarity and sealing performance), Molded and extruded products (improve impact strength and flexibility), Foamed compounds (add durability to lightweight shoe midsoles)

7. Block Copolymers based on Styrene and Butadiene (TPE-S or SBS & SEBS) - produced by anionic polymerization. Styrene monomer is first introduced in a reactor and polymerized using a catalyst, building a low molecular weight block. When the styrene has been reacted, butadiene is added and the polymerization continues and builds a high molecular weight block of polybutadiene. A coupling agent is then added and the SBS block copolymer is created.

8. TPE-S (SEBS) Major Properties
The butadiene block can be hydrogenated to give another soft block with a structure that is close to ethylene butylene random copolymers. The so formed block copolymer is called SEBS. It has a better thermal stability than SBS due to the removal of the double bonds of the rubber block.
TPE-S (SEBS) Major Properties
Soft touch
Room temperature compression set
Tear strength
Transparency
Excellent surface appearance
High elasticity
Non slip
Easy to color
Low hardness (down to 5 Shore A)

9. Polystyrene and polybutadiene being incompatible, the block copolymers are two phases systems. The polystyrene is the dispersed phase that ties the polybutadiene together and behaves like a crosslink.
SBS and SEBS block copolymers are difficult to process. They are compounded with oil, filler and polyolefin's to make them easy to process and to adjust their properties to the applications.
SBS compounds are mainly used in the shoe industry. They are used for low demanding applications where product lifetime is short and long-term UV and thermal stability are not needed.
SEBS compounds are used for more demanding applications in all market segments e.g. grips where the soft touch, anti slip properties, good resistance to oil and grease are needed. TPE-S bond to PP, PE or PS; special grades bond to engineering resins (PA, ABS, PC)

10. TPE-S (SEBS) Major Properties
Soft touch
Room temperature compression set
Tear strength
Transparency
Excellent surface appearance
High elasticity
Non slip
Easy to color
Low hardness (down to 5 Shore A)

11. Thermoplastic Vulcanizates (TPE-V or TPV) are blends of PP with crosslinked rubber, oil and filler produced using a process called dynamic vulcanization.
Production of such compound requires high shear where a thermoplastic and a suitable rubber are first intimately mixed before adding the curatives for the cross linking reaction.
Morphology of the resulting blend is a continuous phase of thermoplastic with crosslinked particles of rubber finely dispersed; the smaller the particle size, the better the properties.
TPE-V based on PP and EPDM are well known and replace crosslinked EPDM, Polychloroprene (CR) and Chlorosulphonated Polyethylene (CSM). E.g. Santoprene®, Vyram®, Geolast®, Vistaflex® from ExxonMobil Chemical.

12. TPE-V (PP) Major Properties
Soft touch
High temperature compression set
Resistance to oil and grease
Long term stress relaxation
Fatigue resistance
Non slip
Easy to color
TPE-V are probably the TPE that have the closest properties to thermoset rubber. They have been successfully introduced as rubber replacement in window profile extrusion, automotive weather seals and suspension bellows. They are used instead of TPE-S as soft touch materials when oil resistance is needed in power tools applications for example.

13. Thermoplastic Polyester Elastomer (TPE-E, COPE) is a high-performance rubber replacement solution that exhibits similar mechanical behavior as rubbers, with the ease of use and recycle of thermoplastics.
TPE-E are built from soft polyether blocks combined with hard polyester blocks. By playing on the polyether / polyester ratio a broad range of hardness can be covered by TPE-E.
TPE-E show a higher thermal resistance than TPE-O, TPE-S and TPU and are widely used in over-moulding applications, leading to competitive manufacturing processes where assembly of two different parts made of two different materials is not a separate step.
Typical industrial applications are shock absorbers, industrial flexible coupling components, high performance sound dampeners etc.

14. TPE-E Major Properties
Typical automotive applications are: covers for airbags, steering wheels, armrests; under-the-hood tubes and hoses, constant velocity joint boots. Typical consumer goods are: soft-grip applications, mobile phone antennas, electronics protective housings, handles.
TPE-E Major Properties
High chemical resistance
High wear-resistance
Good resilience
Good Thermal resistance
High surface aesthetics
Good paintability
E.g. Arnitel® from DSM, Hytrel® from DuPont

15. Polyether Co-polyamides (TPE-A, PEBA) are prepared by reacting a polyamide bearing carboxylic acid end groups and a polyether diol in the presence of a catalyst. Various types of Nylon can be used. The ratio of Nylon to polyether determines the hardness of the TPE-A formed; the type of Nylon determines the thermal behavior (melting point) of the TPE-A.
TPE-A are among the most expensive but also the most performing TPE. They are used in demanding applications where no other TPE can be used or when dynamic properties are required. One property of interest is the almost constant value of the modulus over a wide range of temperatures.

16. TPE-A Major Properties
Low density
Chemical resistance
High strength and toughness
Resilience
Outstanding low temperature properties
Very good dynamic properties
Thermal stability
TPE-A are mainly used in end sport shoes, conveyor belts, silent gears, breathable films etc.
E.g. – Pebax® from Arkema, Vestamid® from Evonik Corp.

17. Thermoplastic polyurethane (TPE-U or TPU) is a class of polyurethane plastics with many useful properties, including elasticity, transparence and resistance to oil, grease & abrasion. Technically they are thermoplastic elastomers consisting of linear segmented block copolymers composed of hard and soft segments.
TPU are formed by the reaction of diisocyanates with short-chain or long-chain diols (so-called chain extenders). The practically unlimited amount of possible combinations producible by varying the structure and / or molecular weight of the three reaction compounds allows for an enormous variety of different TPU.
TPU has many applications including automotive instrument panels, caster wheels, power tools, sporting goods, medical devices, drive belts, footwear, inflatable rafts, electronic devices, variety of extruded film, sheet and profile applications.

18. Main Properties of TPU

19. Main Applications of TPU

20. Selection Criteria for End Applications

21. Hardness Range Covered by the Different Families of TPE

22. Effect of Hardness on Properties

23. Effect of TPE on Hardness / Property Balance
Tensile Strength at Break for 90 Shore A Hardness TPE

24. Service Temperature Range

25. Compression Set at Room Temperature

26. Compression Set at 70°C

27. Oil Resistance (ASTM D2000 / SAE J200)

28. Resistance to Hydrocarbons

29. Resistance to Polar Solvents

30. UV Stability

31. Abrasion Resistance

32. Abrasion resistance of materials vis-à-vis typical TPU compound
Acknowledgements: OMNEXUS

33. Thermoplastic Strip Builder™ by REMCO ®

34. Thermoplastic elastomers including TPUs, TPRs, TPOs and others which have physical properties that compare favorably to their thermoset cousins, add significant additional processing advantages.
No post-application curing required (energy & time saving)
Faster application & lower labour cost (as compared to cast TPU &
thermoset elastomer)
Can be ground to finished diameter after cooling to room temp.
Reuse of process waste & re-grinds (material & cost saving)
Same tooling can be used (extruder and strip conveying system
needs to be changed)

35. THANK YOU Mr. Anomitra Chakravarty
Technical & Project Consultancy in the field of
Elastomers, Thermoplastics, Recycling & Composites