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application notes & technical articles
Test Methods for Characterisation
and Optimisation of Recycling
Polymers
Polymers are used daily in thousands of tons.
Recycling of the used polymers is essential to
reduce the amount of waste. One of the key
problems in polymer recycling is the separation of
the polymers to defined sorts of polymers such as
PE, PP, PVC and Polyesters etc.
Even sorted materials show a wide variation of
biennial 07-08
polymer industries
Powder coatings are a cost effective and
environmentally friendly alternative to liquid
coatings. Traditional coatings systems network
via a thermally activated process. This usually
involves placing a powder coated surface into an
oven between 160°C to 200°C in temperature.
The powder melts at around 80°C to 120°C and
becomes an even film. At temperatures of
between 110°C to 140°C the network reaction
begins. The curing time typically lasts between
15 and 30 minutes, depending on the
temperature and reactivity of the system. New to
the market place are U.V. curing powder coating
systems, where the curing process takes place in
a shorter amount of time, even at temperatures of
below 100°C. A further advantage of the U.V.
induced networking is that it works virtually
independently of temperature. This opens up new
flow behaviour, which eventually precents a
smooth processing of the recycled polymers.
The report describes various test methods to
analyse the flow and processing behaviour of
polymers.
The test were mainly operated with a recycling
granulate, made of HDPE – cosmetic bottles. The
bottles were sorted, grinded and washed to clean
the material and to remove the paper sticking on
the polymer. After drying, the material was
application possibilities for coating heat sensitive
surfaces like wood or synthetics.
When powder coating different substrates it is not
only smooth, tough surfaces that are desired but
also adhesive strength, corrosion protection and
durability.
The melting and curing relationship of powder
coatings can be rheologically analysed using
oscillation tests with an air bearing rheometer.
The advantage of this method is that the
structural change of the coating as a function of
time or temperature can be demonstrated without
disturbing the process ie. at very small oscillation
amplitudes.
The rheological measurements that are usually of
interest are complex viscosity h*, complex
modulus G*, the loss factor tan d as well as the
phase displacement angle d. As many powder
coatings become very hard after the complete
packed in drums for further processing.
The laboratory report includes an overview of the
following test methods: Testing of Melt Flow Rate
(MFR); Capillary Rheology; Laboratory Extruder
Tests; and Laboratory Mixer Tests.
A full copy of “Test Methods for
Characterisation and Optimisation of
Recycling Polymers” is available by quoting
reference no: LR-45
application notes & technical articles
Rheological Analysis of Powder
Coatings
surface coatings
industries
curing process, parallel measurements using
plate plate geometry PP20 with 20 mm plate
diameter are recommended for the rheological
tests.
Rheological analysis of powder coatings takes
place at temperatures of somewhere between
80°C and 250°C. This range can easily be
covered using the electric temperature unit
TC501 with cone heating. The following outlines
some recommendations of practical examples
and typical measurement definitions. All
measurements have been carried out using the
air bearing rheometer Haake RheoStress, with the
high temperature measuring unit TC501 with
cone heating and the parallel plate geometry
PP20 (20mm plate diameter). As a standard
measurement the gap was set at 0.5 mm.
A full copy of “Rheological Analysis of
Powder Coatings” is available by quoting
reference no: V-157
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