JEC COMPOSITES MAGAZINE - Issue #100 - Special JEC Asia - October 2015 - 79

Faster reaction,
shorter cycle times
When it comes to manufacturing and
processing prepregs, polyurethane offers a variety of advantages over epoxy
resins in terms of production costs,
energy savings, environmental and
resource conservation, and processing
flexibility. In addition, it also delivers
improved component properties. The
significantly lower initial viscosity of the
polyurethane reaction resin (less than
100 mPa*s) enables straightforward and
faster wetting of the reinforcing fibre
when manufacturing prepregs.
The polyurethane prepregs also react
faster during pressing than epoxy
systems, meaning that demoulding can
be performed earlier with shorter cycle
times. The benefit for the processor, in
addition to enhanced productivity, is
that fewer prepreg presses are required,
thereby lowering investment costs.
The chemical reaction when pressing
polyurethane prepregs is also markedly less exothermic than with epoxy
systems (see Figure 2). This prevents
heat damage or, worse still, burns, even
when working with thicker component
sections. This greatly extends the field of
possible applications for polyurethane
prepregs. Due to higher elasticity and
notched impact strength, polyurethane
prepregs are less inclined to brittle
fracturing arising from dynamic stresses

Fig. 2: The new polyurethane casting resin system
has significantly lower exothermic reactions than
corresponding epoxy systems (EP = epoxy) (Photo:
Covestro)

and therefore do not suffer from fatigue
as quickly as epoxy systems. In practical terms, components can therefore be
expected to last longer.

Higher glass transition
temperature makes annealing
unnecessary
Following forming, curing and demoulding at around 140°C, polyurethane
prepregs have a higher glass transition
temperature than traditional epoxy systems and are therefore more resistant to
high temperatures. They exhibit the same
mechanical properties as popular epoxy
systems but unlike these, the pressed
components do not require subsequent
heat treatment (annealing/curing) at
over 100°C. In addition, pressing can
usually be performed at lower temperatures. Both deliver noticeable energy
savings that help protect the environment and the climate. Yet, if polyurethane prepreg components are subsequently annealed, the glass transition
temperature of the composite increases
to as much as 175°C, and this is accompanied by an improvement in mechanical
properties.

Practical example - leaf springs
with 25% lower manufacturing
costs
The industrial-scale processing behaviour of the new polyurethane prepregs
was tested in conjunction with IFC
Composite GmbH, Haldensleben,
Germany, employing the type of mould
that could be used for epoxy prepreg
leaf springs for a van, for example. The
use of polyurethane prepregs led to a
manufacturing cost saving of up to 25%
(see Figure 3). Key factors in this were
shorter cycle times and reduced energy
consumption resulting primarily from
lower pressing temperatures and the
elimination of component annealing.
Pressing times could be reduced by
around 40%. The lower costs in prepreg
production, the reduced investment
required for presses and the elimination
of expenditures for prepreg freezers and
annealing ovens also played a part.

Fig. 3: Prepreg pressing system at IFC Composite
GmbH for series production of van leaf springs
(Photo: IFC Composite GmbH)

Outlook: Circuit boards and SMC
In addition to leaf springs, interesting
applications for the new polyurethane
prepregs include printed circuit boards
(PCB). These were previously the
domain of epoxy prepregs and, for cost
reasons, are manufactured in large quantities in highly automated processes. This
is an area where polyurethane prepregs
could help to significantly reduce
production costs further, and related
development projects have already been
launched.

Potential for SMC
Transferring the concept to the field of
SMC component manufacturing is also
a further option for polyurethane casting
resins. For instance, the low initial viscosity enables efficient impregnation of the
fibre mats used in the SMC method. The
faster polyurethane reaction should lead
to shorter cycle times and thus more
cost-effective component manufacturing. The lower exothermic energy of
the polyurethane reaction could pay
particular dividends in the manufacture
of large, thick-walled components such
as truck panels.
Combination with carbon fibres delivers
yet another quantum leap in mechanical
properties, meaning that polyurethane
is poised to tap into new markets and
applications in the future. n

No100 October 2015 / jec

More information:
www.covestro.com

composites magazine 79


http://www.covestro.com

Table of Contents for the Digital Edition of JEC COMPOSITES MAGAZINE - Issue #100 - Special JEC Asia - October 2015

Cover
Edito
Point of view: The future of mass production
Contents
Companies & Business
In brief
Agenda of Events
Applications
Music - An innovative resin for the music industry
Sports & leisure - New quartz fibe prepreg material for a watch
Market
Asia - China & India: two demographic giants in very different composites markets
Industrial property - Statistical patent analysis for composite material shaping
SPECIAL JEC ASIA
15th International JEC Conferences
JEC Asia Innovation Awards Awards 2015
Education - Successful advanced composites projects in Singapore
Process - Reduction of cure cycle time through microwave curing
FEATURE
Propeller - Interchangeable motorboat propel-ler blades made of composites
Revival - The world’s fastest sailing yacht
NDTNon-destructive testing of composites benefits boat acing
Fast boat - A new generation of fast, fuel-efficient boat
Bonding - Primerless structural adhe-sives gain DNV-GL approval for marine applications
Core material - Rowing solo across the pacifi in a 24-foot boat
Research & Development
Damage - Prediction in- and out-of-plane damage in fibe-reinforced composites
Recycling - Using steam thermolysis to recycle carbon fibes from composite waste
Technology & Innovations
Thermoplastic - Easy handling, high- performance thermoplastic solutions for composites
Permeability - Why measure permeability?
Polyurethane - Polyurethane prepregs for cost-effective lightweight construction
Pipe - A new standard in multilayer composite pipe productivity
Index
In the world
JEC COMPOSITES MAGAZINE - Issue #100 - Special JEC Asia - October 2015 - Cover
JEC COMPOSITES MAGAZINE - Issue #100 - Special JEC Asia - October 2015 - 2
JEC COMPOSITES MAGAZINE - Issue #100 - Special JEC Asia - October 2015 - Edito
JEC COMPOSITES MAGAZINE - Issue #100 - Special JEC Asia - October 2015 - Point of view: The future of mass production
JEC COMPOSITES MAGAZINE - Issue #100 - Special JEC Asia - October 2015 - 5
JEC COMPOSITES MAGAZINE - Issue #100 - Special JEC Asia - October 2015 - Contents
JEC COMPOSITES MAGAZINE - Issue #100 - Special JEC Asia - October 2015 - 7
JEC COMPOSITES MAGAZINE - Issue #100 - Special JEC Asia - October 2015 - In brief
JEC COMPOSITES MAGAZINE - Issue #100 - Special JEC Asia - October 2015 - 9
JEC COMPOSITES MAGAZINE - Issue #100 - Special JEC Asia - October 2015 - Agenda of Events
JEC COMPOSITES MAGAZINE - Issue #100 - Special JEC Asia - October 2015 - 11
JEC COMPOSITES MAGAZINE - Issue #100 - Special JEC Asia - October 2015 - Music - An innovative resin for the music industry
JEC COMPOSITES MAGAZINE - Issue #100 - Special JEC Asia - October 2015 - 13
JEC COMPOSITES MAGAZINE - Issue #100 - Special JEC Asia - October 2015 - Sports & leisure - New quartz fibe prepreg material for a watch
JEC COMPOSITES MAGAZINE - Issue #100 - Special JEC Asia - October 2015 - 15
JEC COMPOSITES MAGAZINE - Issue #100 - Special JEC Asia - October 2015 - Asia - China & India: two demographic giants in very different composites markets
JEC COMPOSITES MAGAZINE - Issue #100 - Special JEC Asia - October 2015 - 17
JEC COMPOSITES MAGAZINE - Issue #100 - Special JEC Asia - October 2015 - 18
JEC COMPOSITES MAGAZINE - Issue #100 - Special JEC Asia - October 2015 - 19
JEC COMPOSITES MAGAZINE - Issue #100 - Special JEC Asia - October 2015 - Industrial property - Statistical patent analysis for composite material shaping
JEC COMPOSITES MAGAZINE - Issue #100 - Special JEC Asia - October 2015 - 21
JEC COMPOSITES MAGAZINE - Issue #100 - Special JEC Asia - October 2015 - 22
JEC COMPOSITES MAGAZINE - Issue #100 - Special JEC Asia - October 2015 - 23
JEC COMPOSITES MAGAZINE - Issue #100 - Special JEC Asia - October 2015 - 24
JEC COMPOSITES MAGAZINE - Issue #100 - Special JEC Asia - October 2015 - 25
JEC COMPOSITES MAGAZINE - Issue #100 - Special JEC Asia - October 2015 - 26
JEC COMPOSITES MAGAZINE - Issue #100 - Special JEC Asia - October 2015 - 27
JEC COMPOSITES MAGAZINE - Issue #100 - Special JEC Asia - October 2015 - 28
JEC COMPOSITES MAGAZINE - Issue #100 - Special JEC Asia - October 2015 - 29
JEC COMPOSITES MAGAZINE - Issue #100 - Special JEC Asia - October 2015 - 30
JEC COMPOSITES MAGAZINE - Issue #100 - Special JEC Asia - October 2015 - 31
JEC COMPOSITES MAGAZINE - Issue #100 - Special JEC Asia - October 2015 - 32
JEC COMPOSITES MAGAZINE - Issue #100 - Special JEC Asia - October 2015 - 33
JEC COMPOSITES MAGAZINE - Issue #100 - Special JEC Asia - October 2015 - 34
JEC COMPOSITES MAGAZINE - Issue #100 - Special JEC Asia - October 2015 - 35
JEC COMPOSITES MAGAZINE - Issue #100 - Special JEC Asia - October 2015 - 36
JEC COMPOSITES MAGAZINE - Issue #100 - Special JEC Asia - October 2015 - 15th International JEC Conferences
JEC COMPOSITES MAGAZINE - Issue #100 - Special JEC Asia - October 2015 - 38
JEC COMPOSITES MAGAZINE - Issue #100 - Special JEC Asia - October 2015 - 39
JEC COMPOSITES MAGAZINE - Issue #100 - Special JEC Asia - October 2015 - JEC Asia Innovation Awards Awards 2015
JEC COMPOSITES MAGAZINE - Issue #100 - Special JEC Asia - October 2015 - 41
JEC COMPOSITES MAGAZINE - Issue #100 - Special JEC Asia - October 2015 - 42
JEC COMPOSITES MAGAZINE - Issue #100 - Special JEC Asia - October 2015 - 43
JEC COMPOSITES MAGAZINE - Issue #100 - Special JEC Asia - October 2015 - 44
JEC COMPOSITES MAGAZINE - Issue #100 - Special JEC Asia - October 2015 - 45
JEC COMPOSITES MAGAZINE - Issue #100 - Special JEC Asia - October 2015 - Education - Successful advanced composites projects in Singapore
JEC COMPOSITES MAGAZINE - Issue #100 - Special JEC Asia - October 2015 - 47
JEC COMPOSITES MAGAZINE - Issue #100 - Special JEC Asia - October 2015 - 48
JEC COMPOSITES MAGAZINE - Issue #100 - Special JEC Asia - October 2015 - Process - Reduction of cure cycle time through microwave curing
JEC COMPOSITES MAGAZINE - Issue #100 - Special JEC Asia - October 2015 - 50
JEC COMPOSITES MAGAZINE - Issue #100 - Special JEC Asia - October 2015 - 51
JEC COMPOSITES MAGAZINE - Issue #100 - Special JEC Asia - October 2015 - 52
JEC COMPOSITES MAGAZINE - Issue #100 - Special JEC Asia - October 2015 - Propeller - Interchangeable motorboat propel-ler blades made of composites
JEC COMPOSITES MAGAZINE - Issue #100 - Special JEC Asia - October 2015 - 54
JEC COMPOSITES MAGAZINE - Issue #100 - Special JEC Asia - October 2015 - Revival - The world’s fastest sailing yacht
JEC COMPOSITES MAGAZINE - Issue #100 - Special JEC Asia - October 2015 - 56
JEC COMPOSITES MAGAZINE - Issue #100 - Special JEC Asia - October 2015 - NDTNon-destructive testing of composites benefits boat acing
JEC COMPOSITES MAGAZINE - Issue #100 - Special JEC Asia - October 2015 - 58
JEC COMPOSITES MAGAZINE - Issue #100 - Special JEC Asia - October 2015 - Fast boat - A new generation of fast, fuel-efficient boat
JEC COMPOSITES MAGAZINE - Issue #100 - Special JEC Asia - October 2015 - 60
JEC COMPOSITES MAGAZINE - Issue #100 - Special JEC Asia - October 2015 - Bonding - Primerless structural adhe-sives gain DNV-GL approval for marine applications
JEC COMPOSITES MAGAZINE - Issue #100 - Special JEC Asia - October 2015 - Core material - Rowing solo across the pacifi in a 24-foot boat
JEC COMPOSITES MAGAZINE - Issue #100 - Special JEC Asia - October 2015 - 63
JEC COMPOSITES MAGAZINE - Issue #100 - Special JEC Asia - October 2015 - Damage - Prediction in- and out-of-plane damage in fibe-reinforced composites
JEC COMPOSITES MAGAZINE - Issue #100 - Special JEC Asia - October 2015 - 65
JEC COMPOSITES MAGAZINE - Issue #100 - Special JEC Asia - October 2015 - 66
JEC COMPOSITES MAGAZINE - Issue #100 - Special JEC Asia - October 2015 - 67
JEC COMPOSITES MAGAZINE - Issue #100 - Special JEC Asia - October 2015 - Recycling - Using steam thermolysis to recycle carbon fibes from composite waste
JEC COMPOSITES MAGAZINE - Issue #100 - Special JEC Asia - October 2015 - 69
JEC COMPOSITES MAGAZINE - Issue #100 - Special JEC Asia - October 2015 - 70
JEC COMPOSITES MAGAZINE - Issue #100 - Special JEC Asia - October 2015 - 71
JEC COMPOSITES MAGAZINE - Issue #100 - Special JEC Asia - October 2015 - Thermoplastic - Easy handling, high- performance thermoplastic solutions for composites
JEC COMPOSITES MAGAZINE - Issue #100 - Special JEC Asia - October 2015 - 73
JEC COMPOSITES MAGAZINE - Issue #100 - Special JEC Asia - October 2015 - 74
JEC COMPOSITES MAGAZINE - Issue #100 - Special JEC Asia - October 2015 - Permeability - Why measure permeability?
JEC COMPOSITES MAGAZINE - Issue #100 - Special JEC Asia - October 2015 - 76
JEC COMPOSITES MAGAZINE - Issue #100 - Special JEC Asia - October 2015 - 77
JEC COMPOSITES MAGAZINE - Issue #100 - Special JEC Asia - October 2015 - Polyurethane - Polyurethane prepregs for cost-effective lightweight construction
JEC COMPOSITES MAGAZINE - Issue #100 - Special JEC Asia - October 2015 - 79
JEC COMPOSITES MAGAZINE - Issue #100 - Special JEC Asia - October 2015 - Pipe - A new standard in multilayer composite pipe productivity
JEC COMPOSITES MAGAZINE - Issue #100 - Special JEC Asia - October 2015 - Index
JEC COMPOSITES MAGAZINE - Issue #100 - Special JEC Asia - October 2015 - In the world
JEC COMPOSITES MAGAZINE - Issue #100 - Special JEC Asia - October 2015 - 83
JEC COMPOSITES MAGAZINE - Issue #100 - Special JEC Asia - October 2015 - 84
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