Plastics News Europe - June 2019 - 27

elastomers

tPes: a durable
success
While TPEs were not successfully commercialised
until the 1960s, once on the market, they were there
to stay. Easier to process than thermoset rubber,
colourable and recyclable, they have been called 'the
most innovative material in their class.' One company
that quickly caught on to the benefits of these
materials was Hexpol TPE. By Karen Laird

W

ith a history in flexible polymer compounding that
stretches back over 50
years, Hexpol TPE was among the
first to start producing thermoplastic
elastomers in Europe. "Our parent
company, the Hexpol Group, which
dates back to 1893 and had primarily
been known for rubber compounds
and products, diversified into TPEs
when they acquired our Swedish and
UK operations in 2010," Jill Bradford,
group marketing and PR manager,
Hexpol, told Plastics News Europe.
"We were joined by our two German
sites in 2012 and we added production capabilities in China in 2013 and
North America in 2016."
Thermoplastic elastomers, or
TPEs, as they are usually known,
mainly owe their popularity to the
fact that, despite having many of the
physical properties of vulcanised rubber, they can be processed as thermoplastics, on conventional plastics
processing machinery via standard
plastics technologies such as injection
moulding, extrusion, blow moulding
and thermoforming. Unlike thermoset rubbers, they do not need to be
cured. They are also recyclable. As a
result, they have often been described as the bridge between plastics and rubber.
Bradford: "They are, in fact, compounds of elastomers together with a
thermoplastic - for example, polypropylene - a processing oil and sometimes a filler - to give a highly customisable material with additional
properties to the base elastomer."
As a consequence, TPEs share various characteristics with elastomers;
they are flexible, elastic and available
in a wide range of hardnesses. They
are good sealers with a tactile, softtouch feel. This is combined with the
colourability, processing and recycling advantages of plastics. Unlike

june 2019

the chemical cross-linking which occurs in thermoset rubbers, TPE involves purely physical cross-linking,
which can be reversed with the further application of heat. This makes it
possible to re-use production waste
and end of life products can be easily
reprocessed.
Jill Bradford: "TPEs don't have the
high strength, heat and chemical resistance of a thermoset rubber and
you won't find them being used to
make your car tires. But their design
flexibility, recyclability and ease of
processing has led to designers turning to TPEs for an array of applications in the consumer, medical, construction, electronics and automotive
markets."
There are, she said, numerous applications where TPEs are successfully
replacing the traditional materials
used. "Areas where we've been seeing TPEs substituting alternative materials include replacement of PVC
and vulcanised rubber, an ongoing
process since several years. Examples
include automotive floor mats, where
many companies have switched from

Dryflex Green TPEs are soft,
plant based plastics

rubber to TPE or medical tubing,
where TPE is being used in place of
flexible PVC."
An area where TPEs have clearly
won the day is that of multi-component processing and overmoulding
applications, for example 2K, insert
moulding or co-extrusion. In overmoulding applications, one material,
often a soft TPE, is moulded onto
another material, usually a hard
thermoplastic, using a multi shot
process or by insert molding. This
makes it possible to create softtouch areas and tactile surface finishes, for enhanced functionality,

➡ Continued on page 28

Dryflex Green plant based TPEs are being used to produce consumer goods, toys,
automotive interiors and sports equipment such as the lid and harness of this sports
bottle from Emballator Lifestyle AB of Sweden

27
Plastics News Europe - June 2019

Table of Contents for the Digital Edition of Plastics News Europe - June 2019
