JEC COMPOSITES MAGAZINE - Issue #121 - May 2018 - 39

LAND TRANSPORTATION
coating

A new platform for producing
Class A surface quality components

Lars Friedrich,
Head of the TRAC Application Laboratory
dr. Francis deFoor,
Global Market Segment Leader
Transportation
Hexion
ManueL seiz,
Business Unit Manager
doris KretzschMar,
Development Engineer, RIM technology
Votteler

T

he automotive industry is evolving rapidly with increasingly
rigorous emission targets, leaps
toward electrification, and a push
toward autonomous driving. These
forces continue to trigger lightweight
solutions, advancing the adoption of
novel composite materials for diverse
applications. Composite materials
have been used for body parts in sports
and luxury vehicles for a long time,
enabling design freedom, astonishing
aesthetics and leading-edge driving
performance.
Today, visible composite parts are
mainly produced using pre-impregnation (prepreg) or resin transfer
moulding (RTM). However, the production of complex-shaped parts using
prepregs is cumbersome because of
their limited drapeability. In addition,
the fabrication of the pre-impregnated
intermediates adds an expensive process step.
In contrast, RTM is an attractive alternative that provides greater design
freedom, as well as higher build rates
thanks to shorter cycle times. However,
there is normally a trade-off between

This article introduces the PuriCoat platform for producing Class A
surface quality, visible lightweight components within a very short
cycle time. Through close technical collaboration between a coatings
developer and a specialty chemicals company, products and process
conditions were optimized to achieve excellent coating quality and
durability. Furthermore, for industrial manufacturing, this platform's
negligible emission levels address the growing regulatory demand for
VOC-free solutions. With substantial cost savings and the potential for
high build rates, PuriCoat makes coated visible interior and exterior
parts more accessible than ever.

surface quality and RTM cycle times
due to the so-called fibre print-through
effect. This phenomenon is caused by
the mismatch between the thermal
expansion coefficients of the resin and
fibre, and shows up during the cooldown of moulded parts. The effect can
be minimized by applying relatively
low RTM operating temperatures - 8090°C - and through additional surface
treatment and coating steps.
New platform combining fast-cure
epoxy RTM with an in-mould
polyurethane coating
The new PuriCoat platform, jointly developed by Hexion and Votteler, allows
the cost-efficient, eco-friendly production of coated exterior parts. This
platform combines Hexion's fast-cure
EPIKOTE™ resin 06000 / EPIKURE™
curing agent 06130 system suitable
for mass-producing structural carbon
fibre-reinforced polymer (CFRP)
parts with Votteler's PURIFLOW®
PU911IR reaction injection moulding
(RIM) PU coating system suitable for
in-mould coating of various substrates,
including CFRP components.
The constituent products in PuriCoat
are already known as high performers.
On the one hand, Hexion's EPIKOTE

resin 06000 / EPIKURE curing
agent 06130 system is currently in
commercial use for the production of
structural parts by BMW [1]. Due to
its low shrink characteristics, this system is also suitable for the production
of visible parts. The product exhibits
a low viscosity and latency as needed
for RTM processes, and a short curing
time. The internal mould release agent
HELOXY™ additive TRAC 06805 can
be used for fast, easy demoulding.
On the other hand, various car manufacturers have already approved
PURIFLOW® paint systems from
Votteler. These coating systems offer
very high chemical and mechanical
resistance, as well as resistance to heat
and climate, yellowing and UV light.
And since not every scratch can be
avoided despite its high resistance,
surfaces produced with PURIFLOW®
are equipped with a self-healing effect:
scratches will regress through a reflow
effect.
PURIFLOW® coating systems can be
adjusted or produced in transparent,
pigmented, piano-black or innovative
effects. The newest products are
supplied with internal release agents
for increased productivity and to eliminate the need for further processing,
such as polishing.

N°121 May - June 2018

/ jec composites magazine

39
Table of Contents for the Digital Edition of JEC COMPOSITES MAGAZINE - Issue #121 - May 2018
