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A new technology platform now offers foundries the possibility to work with acold box part 1 that does not contain any hazardous substances subject to labelingrequirements and that helps them to significantly reduce their phenol emissions.

Newest technology platform forcold box binders
Emissions form in the various phasesof the foundry process. When usingorganic binders, pollutants are emitted
that can be harmful for workers and theenvironment. During core productionsome of the solvent as well as volatilecomponents like amines and residual
monomers contained in part 1 of thecold box formulation evaporate orvaporise. In some cases, this involves
volatile organic compounds (VOCs) that
can also be highly odorous. VOCs havebeen comprehensively identified andclassified by the European Union(1).

Components of a typical cold box
formulation
In the cold box amine process, amines
are used for the hardening of cores andmoulds. When investigating emissions
in the foundry process, the solventswith a low boiling point that are usedin part 1 and/or part 2 must be taken
into account above all. These arearomatic solvents, in particular, that are

produced via the fractional distillationof crude oil, and organosilicate solvents.
Such solvents are used to reducethe viscosity to a level suitable forprocessing and to optimise the various
core characteristics.
To produce a typical phenolic resin,a polymer is synthesised from phenol
and formaldehyde that can still containresidual monomers such as phenol
and formaldehyde as a result of an
incomplete reaction.
Also, certain additives that are used
for the optimisation of the binder
performance (moisture resistance,
processing time, etc.) can prove to be
toxic for workers.

Occupational exposure limits andvolatility of hazardous substances
There are numerous products withspecial compositions on the market thatare less harmful or dangerous according
to the information provided by the
manufacturers. However, how are theFig.1 Occupational exposure limits and vapour pressurerisks of a binder evaluated? In Europe, all hazardous
substances are classified in accordance with the GHS/
CLP Regulation and must be declared in the safety data
sheet.
On the basis of various studies, the European Union
has specified a certain occupational exposure limit (OEL)
for each identified hazardous substance. This refers to
the acceptable upper limit (concentration within a given
time frame) up to which a worker may be exposed tothe particular chemical in the workplace. The lower the
OEL, the more hazardous the chemical is classed as.
The volatility of a chemical is another parameterthat influences the health of a worker. Volatility can beassessed on the basis of the vapour pressure. The higher
the vapour pressure, the easier it is for the chemical
to vaporise and the higher its concentration is in theworkplace air.
For occupational health and safety, it is therefore
always better to use chemicals with the highest OEL - orideally chemicals that require no OEL - and the lowest
vapour pressure.

Odour detection threshold is not reliable
To evaluate the risks of a chemical, the odour detection
threshold is also often used as a parameter. Odour
helps us to detect the presence of molecules in the
air. However, the same odour can be an irritant to
one person while another may perceive it as being
pleasant. This is completely dependent on the specificcircumstances and the individual acclimatisation tothe odour. The odour detection threshold is thus a
subjective parameter that does not provide reliable
information about the risk or safety of a chemical.
Of course, the odour can constitute a selection
criterion for the selection of binders; however, it should
not be the only evaluation benchmark. A strong odour
can also indicate that the area is insufficiently ventilatedor that the extraction system is not efficient enough,for example. A stronger-smelling product must never beexchanged offhandedly for an odourless binder without
considering the OEL and the vapour pressure of thealternative products. For instance, if the supposedly
harmless (odourless) product has the lowest OEL andthe highest vapour pressure, the changeover would
constitute a much greater hazard for the worker.

Emissions during casting

Table 1 ECOCURE BLUE does not contain any substances and/or concentrations subject to labelingrequirements in part 1 of the formulation

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Developments in recent years show that emissions
during core production can be avoided or at least
localised and removed in an appropriate manner. The
majority of pollutants in foundries occur during casting.
Their formation occurs in three phases - due to thehigh temperatures, a large part of the solvent, which iscontained in the core and mould, the phenol and theformaldehyde as well as the further residual monomers
vaporise. In the second phase, the polyurethane chainscombust as a reaction to the oxygen in the mould, theFOUNDRY TRADE JOURNAL October 2016

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cores and the surfaces are exposedto the air. This is known as complete
combustion. As soon as the oxygen
content is too low, what is known as‘pyrolysis’ begins, i.e. the thermal
decomposition of organic compounds
or other reaction partners. Dependingon the temperature gradients and gas
pressures in the various areas of thecore, the organic substances containedin the binder are combusted, gasified,cracked and condensed again. During
this, what are known as ‘free radicals’
form that can be reformulated into
new forms. This leads to the formingof pyrolysis products such as BTX(benzene, toluene and xylene)
as well as CO, NOx or other HAPs
(hazardous air pollutants). Factors
such as temperature, the ratio ofoxygen content to the percentage
of organic compounds in cores andmoulds, etc. play an important role inpyrolysis. Alongside the compositionof the binder, application-specificparameters such as core and mould
geometry, the ratio of sand to metal,
the casting temperature or the ingate
system, greatly influence the releaseof pollutants.
ASK Chemicals has thoroughly
investigated these emissions in recent
decades. For this purpose, what is
known as the ‘Hoodstack device’has been used (alongside otherprocedures), which was developedby Ashland. Tests with the Hoodstackprovide information on the extent
to which the binder composition
influences the composition of theemissions. Hoodstack analysis enables
the recording of the VOCs, carbon
monoxide (CO), carbon dioxide (CO2),
nitrogenous gases (NO, NO2, NOX) andsulfurous emissions (e.g. SO2). Lead
substances - e.g. benzene, toluene,
xylenes, phenol and formaldehyde- can be recorded via absorption on
appropriate media and quantified
via subsequent chemical analysis.
Hoodstack analysis allows emissions
from the casting, cooling anddemoulding process to be monitored,
depending on the configuration of thecore and/or mould package.
ASK Chemicals was able todemonstrate that the main emissions
are monomers, BTX and NOX.
Monomers form within split seconds
after casting via vaporisation. BTX andNOX form in the further course of thecasting phase.
Building upon this newly obtained
knowledge, the company introduced
a new generation of binders in 2008
with the ‘ECOCURE™ High Efficiency’
cold box binder that was continuously
developed and supplemented in 2014
by the solventless cold box system‘ECOCURE SL’. An extremely effective
measure, albeit a slightly surprising
realisation, is that the reduction of
the organic material in the core andmould proves to be one of the mosteffective ways of minimising emissions
in every stage of the foundry process
and particularly during casting. A
main focal point at ASK Chemicals isthe development of solutions thatenable the achievement of the same
performance level with a reduced useof binders.

ECOCURE™ BLUE - the first coldbox binder without substances
subject to labeling requirementsin part 1
The starting point for the developmentof the latest technology platform fromASK Chemicals was the knowledge
surrounding the following three
specific emission sources:• Evaporation of volatile compounds
during core production (mixing,
shooting, storing, etc.)• Evaporation of the residual phenol
and formaldehyde monomers andsolvents with a higher boiling point
during the first split seconds ofcasting.
• Emission of BTX (and otherproducts of decomposition) during
the casting phase due to thepyrolysis of the carbon backbone
chain of the polyurethane
polymers.
Solutions for the first two emission
sources have also been in intensive
development for a number of decades.
Numerous suppliers are now alreadyoffering cold box binder systems that
dispense with VOCs entirely. In simple
terms, we can say that the majority
of cold box systems on the market
that do not contain any aromatic and/or TEOS solvents can be sold as being
free from VOCs in accordance with
European law.
The development of the HE andSL systems by ASK Chemicals aims
specifically at a reduction of the third
emission source. The reduction of theadded amounts of binder is equivalent
to a lower organic load and thus leads
to reduced emissions during pyrolysis.
The targeted reduction in monomer
content (especially free phenol)
was for a long time neglected in
the course of the aforementioned
modifications. This is unsurprising as
the development of such solutions
is considerably more complex andinvolves significantly more research
effort. This also includes the need toconsider new production procedures
and modifications to existingproduction systems.
The result of such an intensive

FOUNDRY TRADE JOURNAL October 2016

Fig.2 Schematic depiction of the Hoodstack set-up

Fig.3 High-efficiency or solventless cold box binders enable a
reduction in the binder agent while providing higher initial and final
strengths

Fig.4 Comparison of the bending strength of ECOCURE BLUE andECOCURE 30 HE 1 LF with various sand qualities from Western
Europe. All tests were performed with 0.7 per cent per part with thecatalyst 706 (DMPA)

Fig.5 Comparison of the processing time of ECOCURE BLUE andECOCURE 30 HE 1 LF with various sand qualities from Western
Europe. All tests were performed with 0.7 per cent per part with thecatalyst 706 (DMPA)

development is the new cold box technology ECOCURE™
BLUE, which is based on a phenol resin in which theconcentration of substances subject to labeling requirements
was substantially undershot or where such substanceswere omitted completely. Labeling with a hazard symbol
is therefore not necessary. Substances and concentrations
subject to labeling requirements refers to the substances andconcentrations that have to be declared in chapter 3 of thesafety data sheet as per the new European CLP Regulation.

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GREENSPEAKECOCURE BLUE does not containany components that have to be
declared due to their OEL (with the
exception of DBE in Germany) orthat exceed the concentration limit
for hazardous substances. Only part2 of the cold box formulation is stillbased on isocyanate, which must be
declared.
Products that are based on the‘ECOCURE BLUE’ platform combine
the advantages of the ‘ECOCURE
high-efficiency’ binders, which are
known on the market, with theadvantages of the ‘ECOCURE BLUE’technology, and so enable thefoundry to optimise the emissions
along the entire value added chain.
The foundry therefore receives
a product that does not containany substances subject to labelingrequirements in the part 1
component and that additionallyhas the technically superior
performance of the high-efficiency
technology. Its reactivity and theability to specifically optimise initialstrengths - a deciding factor in theselection of the binder system - arewhat distinguish high-efficiency
technology.

Performance comparison
The development of cast parts
constantly presents new challenges
for foundries and raw material
suppliers. Core geometries are
becoming increasingly more
complex. Thin-walled casting isplaying an increasingly larger role particularly in the automotive field.
Solutions for increased productivity
to ensure the competitivenessof foundries are becoming evermore important in all areas.
Thus, extremely short cycle times
are a significant requirement incore production. Furthermore,environmental considerations are
one of the key parameters in theselection of the appropriate cold box
technology for European foundries
in particular.
A new binder that lives up to
all of these requirements or evenexceeds them must distinguish itself
via exemplary mechanical strengths
and an excellent reactivity for shortcycle times, as well as very good
casting results and with as minimal
an influence on the environment,
health and occupational safety as
possible.
The first product of the newtechnology platform ECOCURE
BLUE 30 HE1/ECOCURE BLUE 60
HE 1 achieves the good technicalperformance of ECOCURE 30 HE
1 LF/ECOCURE 60 HE 1 LF (2nd242

generation high-efficiency system),
which is said to be the best nonaromatic system on the market
and is used in nearly all European
countries for iron applications.
Various cold box systems available
on the market were examined via
the Hoodstack analysis regarding theemissions that formed during thecasting process.
The analysis of the VOCs during
casting, cooling and demoulding
reveals a clear reduction whenusing this new technology platform
compared to aromatic or TEOS
systems.
The analysis particularly focusedon the phenol and BTX emissions
that form at the start of casting via
pyrolysis.
When examining the results, it
was possible to once again confirm
that the most efficient method ofminimising BTX emissions is the
reduction of the added amountsof binder. This can be identified
in the measurement values of the
ECOCURE HE system, which on
average emits fewer emissions thancomparable systems.
Moreover, with the ECOCURE
BLUE platform the phenol
emissions - and therefore also the
proportion of free phenol content- are significantly reduced. Aftercomprehensive tests, ASK Chemicals
undertakes that foundries employing
the ‘ECOCURE BLUE HE’ systems can
reduce the phenol emissions during
casting by up to 80 per cent.
Initial experiments in foundries
have shown that particularly thephenol content in waste sand canbe reduced by at least 20 per cent,sometimes even up to 50 per cent depending in the procedure and thequantity of the new core sand used
- via the use of this new technology
platform.

Conclusion
For the first time ever, this newtechnology platform offers foundries
the possibility to work with a coldbox part 1 that does not containany hazardous substances subject
to labeling requirements and thathelps them to significantly reduce
their phenol emissions. Initial
experiments also show a reductionin the phenol content in waste sand,which can have positive effects
on the class of landfill and thecorresponding costs.
That ecology and economy,
which do not have to be mutually
exclusive, is demonstrated by the
new ECOCURE BLUE HE systems,
which are in no way inferior to

Fig.6 VOC emissions during casting, cooling and demoulding (using
Hoodstack method)

Fig.7 As a result of higher strengths, the binder quantity can be
reduced with ECOCURE HE and ECOCURE HE BLUE

Fig.8 The BTX emissions from the pyrolysis of the polyurethane canbe significantly reduced with ECOCURE BLUE and ECOCURE HE via
the reduction in binder quantities

Fig.9 The technology platform ECOCURE BLUE can reduce phenol
emissions during casting by 80 per cent

the current best cold box binders available on the market
regarding reactivity, strengths and casting results. This
technology was developed for iron and steel casting andis not only recommended for the production of hydrauliccomponents, turbochargers, brake disks and engine blocks,
but also for other application areas.
The new technology platform ECOCURE BLUE can be usedwith all common sand qualities (quartz, special sands andreclaimed sands) and is compatible with numerous sandadditives (organic, inorganic or hybrid additives).
All catalysts currently available on the market can be used.
Naturally, the new technology platform is very compatible
with water-based and alcohol-based coatings.

Reference

1. Solvents Emissions Directive 1999/13/EC.
Contact: ASK Chemicals GmbH, Germany, Tel: +49 211 71103 0,
email: info@ask-chemicals.com web: www.ask-chemicals.com

FOUNDRY TRADE JOURNAL October 2016