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TYPES OF TPEs

& SELECTION CRITERIA FOR

END APPLICATIONS

© ANOMITRA CHAKRAVARTY

KPS CONSULTANTS & IMPEX PVT. LTD.www.kpsimpex.com

ETDS CONFERENCE – DELHI, 5 th. MARCH 2014

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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

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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.

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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)

5) Polyether Co-polyamides (TPE-A)

6) Thermoplastic Polyurethanes (TPE-U)

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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

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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)

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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.

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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)

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.

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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)

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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)

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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.

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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.

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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.

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TPE-E Major Properties

High chemical resistance

High wear-resistance

Good resilience

Good Thermal resistance

High surface aesthetics

Good paintability

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.

E.g. Arnitel® from DSM, Hytrel® from DuPont

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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.

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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.

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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.

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Main Properties of TPU

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Main Applications of TPU

Selection Criteria for End Applications

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Hardness Range Covered by the Different Families of TPE

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Effect of Hardness on Properties

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Effect of TPE on Hardness / Property Balance

Tensile Strength at Break for 90 Shore A Hardness TPE

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Service Temperature Range

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Compression Set at Room Temperature

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Compression Set at 70°C

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Oil Resistance (ASTM D2000 / SAE J200)

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Resistance to Hydrocarbons

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Resistance to Polar Solvents

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UV Stability

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Abrasion Resistance

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Abrasion resistance of materials vis-à-vis typical TPU compound

Acknowledgements: OMNEXUS

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Thermoplastic Strip Builder™ by REMCO ®

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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)

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THANK YOU

Mr. Anomitra Chakravarty

Technical & Project Consultancy in the field of

Elastomers, Thermoplastics, Recycling & Composites

www.kpsimpex.com