Conference reviews TPE materials and additives

Edited by the Engineeringtalk editorial team Nov 24, 2006

The main focus of the 9th International TPE conference organised by Rapra Technology was on new materials and additives entering the market.

The main focus of the 9th International TPE conference organised by Rapra Technology was on new materials and additives entering the market.

TPEs are continuing to gain market share by rubber substitution but the competition between different TPE materials is becoming more aggressive.

GLS and Polyone presented new compounds to improve bonding to thermoplastic substrates.

Oneflex-S styrenic grades (KE and KA) from Polyone have been modified to achieve good adhesion against polar materials (PA, ABS, PC, acrylics etc).

One advantage compared with other TPE materials is softer grades can be used.

The new grades also achieve similar or better compression set performance compared with TPV grades.

Kuraray and Kraiburg presented papers on modified styrenic TPEs whose performance is now approaching the properties of TPV materials at potentially lower cost.

Improved high temperature performance is being achieved by crosslinking both the hard and soft block segments.

Kraiburg claimed an upper operating temperature limit of 140C.

One advantage of these new styrenic grades is a wide operating temperature window as superior low temperature performance is retained.

The grades are also suitable for compounding with polypropylene and polyethylene.

Thermoplastic polyurethanes offer significant advantages for abrasion resistance compared with other TPE materials but have been restricted to relative hard grades.

Mergoirisa, specialists in TPUs, have developed two softer grades without the use of plasticisers.

The lower hardness limit has now been reduced to 55 Shore A.

To overcome yellowing due to UV degradation, a new aliphatic 70 Shore A grade has been developed which shows a step improvement is performance compared with UV stabilised grades.

Kraton presented a new additive MD6698 which was able to both improve melt strength and extensibility for a wide range of TPE materials.

The main benefit of this additive is for processes such as foaming, film blowing and thermoforming.

Another advantage is that lower processing pressures are required thereby enabling faster throughput of material.

For foamed materials, Huntsman presented data on Smartlite.

Blowing agents are incorporated onto the surface of the pellets.

The material is finding good application for the footwear industry as the friction properties are retained in the wet and after use (worn surface).

In response to new legislation (RoHS, WEEE, TCO99, Blue Angel) Ticona presented a new copolyester grade, Riteflex XFR.

This is a non halogenated, flame retarded system achieving a UL94V0 rating.

Low migration of the additive also minimises any corrosion issues with copper and the material also exhibits excellent comparative tracking resistance.

Possible applications for this new material include wire coating and electrical connectors.

Kaneka Corporation presented a SIBS grade (styrene isobutylene-styrene triblock copolymer) which showed improved properties compared with SBS and SEBS grades.

Good retention of tensile properties is achieved after ageing up to 150 deg C.

The main benefit of the material is very low permeability (similar or better to typical values quoted for butyl rubber) and corresponding good damping performance.

Rapra Technology has announced dates for next year's TPE event, which will take place at the Renaissance Hotel in Cologne on 23rd and 24th October 2007.

TPE 2007 will be held during the week of K, only 30 minutes from Dusseldorf, thereby taking advantage of having everyone in one place at the same time.

Papers are now being invited for submission for what will be the tenth TPE conference.