Smart-Formulation-Journal-2012

Smart Formulating Journal
Issue 9 | April 2012
Widening the Scope for Matting
Solvent-Free UV-Cured Coatings
Page 6
TEGO® AddBond –
the Multitasking
Adhesion Promoter!
Page 7
High technology
in the store cupboard
Page 9
Because we love your problems, we’re the perfect
partner when it comes to coatings.
“We love your problems.” That’s what we call our international market initiative, and it will also be part of our presence
at a number of coatings shows. But the message is far more than a campaign; it’s an expression of how we see ourselves.
We love your problems, and that’s why we work with you, channeling all our commitment and creativity into developing
solutions for your coating issues.
▸▸▸
Editorial
Dear Readers,
Dear Customers and Evonik Business Partners,
What you have before you right now is the ninth issue of
our customer magazine for the paints and coatings market,
in which we have again provided you with an update on the
latest developments at Evonik.
“Evonik is specialty chemicals”. That was my message to
you in the previous issue of our SF Journal. It is based on
this strategic policy principle that Evonik has launched an
ambitious growth program for its activities in the chemicals
field. That program is already bearing discernible fruits
in many areas of our enterprise operations. In a move,
for example, to lend added strength to our activities in
the coatings market–one of the focus markets for Evonik
growth–we concluded the acquisition of Hanse Chemie AG
and Nanoresins AG in 2011.
Acquisition is one course we have been taking, but Evonik
also aims, more importantly, to achieve organic growth,
in the pursuit of which we have mapped out other key
avenues of enterprise development. In Shanghai, for example,
we are in the process of building our fifth isophorone
production line. In addition, we are building two coatings
development labs in Shanghai and Singapore as well. Each
of these planned investments reflects our unequivocal
acknowledgement of the growing significance which the
markets of Asia enjoy. We will by no means, of course,
be neglecting our traditional markets, and will be making
further targeted investments in these markets, too. In
Essen, for example, we are currently building a new innovation
center for our Coatings & Additives Business Unit.
What all these investments have in common is that they
help us to achieve better market proximity and closer
proximity to you, our customers. Optimized proximity is
an imperative in the context of our aim to achieve improved
resource efficiency. For it is only on a basis of trusting
and affirmative dialog that new, eco-friendly, customized
solutions will evolve. Thus, we are investing not only in
new products and facilities, but equally in our network
of experts who will continue to work together with you
across our various business units to consolidate our Know-
How in the Area of Competence “Coating & Bonding
Technologies”. We wish for you to perceive us as a partner
and problem solver with whom you are eager to collaborate
on achieving continued success for your business.
In this issue of the SF Journal we illustrate how we
are able to find solutions to the problems our customers
encounter. We report, for example, on how
SILIKOPUR® 8080 can substantially improve abrasion
resistance in air-drying PU dispersions and how ACEMATT®
can mat UV-curing coatings. We also report on silica nanocomposites,
solvent-free deaerators for high solid coatings,
and much, much more.
In addition to providing information on all these themes
in this latest issue of the SF Journal, I invite you to actively
engage in further discussions and collaboration with us
in pursuit of the goal as proclaimed by the motto of this
year’s American Coatings
Show: “Preparing for Future
Demands”.
Kind regards
Dr. Thomas Haeberle
Member of the Board of Management
of Evonik Industries

2
We love your problems – at first that might seem a strange
thing to say. Evonik loves my problems? Do they want me
to have problems? Far from it. But problems, challenges and
solving them are part of everyday business. So it’s good to
have a partner who’s committed to solving your problems
and developing forward-looking solutions with commitment
and creativity. That’s the core message behind “We love your
problems”. For us, every problem is an opportunity to develop
great solutions, solutions that are dovetailed to your needs
because we’ve developed them together with you. Here are
three examples to demonstrate just what we mean.
Coatings with Fish Eyes
When spraying modern high-solids coatings, there are
often problems like blisters, fish eyes and other defects.
The biggest challenge was to find an additive that reliably
prevents these problems while displaying good compatibility.
To solve this problem, we worked closely with
a number of our customers. As a result of our working
together, two new deaerators for high solids coatings have
been developed, TEGO® Airex 990 and TEGO® Airex 991,
that can reliably prevent foam / blister formation even in
high film thicknesses and give our customers greater freedom
in choosing the type and quantity of solvents for their
coating.
Cans in Danger
The inner coating of a food can has a lot to put up with.
During forming as part of the manufacturing process, it
has to be flexible and yet still retain its high hardness.
But that’s only the start. It then has to withstand the high
temperatures of the sterilization process and display lasting
resistance to aggressive contents such as acetic acid
in order to prevent metal particles getting into the food.
That’s a lot of work for a coating and, above all, for the
binder. The solution: DYNAPOL®. Our polyester resins
offer optimum protection, high flexibility in the manufacturing
process, a level of temperature resistance that can
withstand sterilization at 130 degrees Celsius, and high
resistance to aggressive contents.
Film Shrinkage Under the Spotlight
The absence of a solvent often causes problems in the
matting of UV-curable coatings because the necessary
film shrinkage does not take place and has to be replaced
by other mechanisms. For this reason, we channeled a
great deal of passion into conducting an extensive series
of painstaking tests to find out how to provide effective
matting for UV-curable coatings.
The result: Our new matting agent ACEMATT® 3600
which, thanks to its special surface treatment, permits
effective matting without solvents and so gives our customers
more freedom in formulating matt, UV-curable
coatings.
Curious about how exactly we went about things in our
three examples? This issue deals with these topics in great
detail. Happy reading!
Contact
Dr. Ulrich Küsthardt
ulrich.kuesthardt@evonik.com
DEGALAN® Resins – Excellent Base for Formulating
Intumescent Paints
Intumescent paints are functional coatings that expand
their volume under heat building a foam. This foam works
as heat shield protecting the substrates from direct fire
contact and thus delaying the spread of fire. More time
for the rescue of people is available and protection against
massive damages. Essential for high protection is a uniform
foam structure and height. Typically intumescent
paints are based on a polymer, a catalyst (e. g. aluminum
phosphate), a carbon source (e. g. pentaerythrit) and a
foaming agent (e. g. melamine). DEGALAN® resins based
on thermoplastic (meth)acrylics are ideal binders for intumescent
paints as they simply do not influence the foam
development.
In fact the DEGALAN® polymers shield the water sensitive
paint ingredients, reduce mechanical impacts, promote
adhesion on several substrates and give excellent
UV-resistance. Thus DEGALAN® resins help in formulating
efficient intumescent coatings.
Contact
Andreas Olschewski
andreas.olschewski@evonik.com
Smart Formulating Journal | Issue 9 | April 2012

3
Corrosion Protection Systems
Environmentally Friendly Solutions with Novel Water-Borne Silane Sol-Gel Formulations and Water-Borne Coatings
Aluminium alloys are used extensively in the aerospace,
automotive and construction industry because of their
low density and high strength to weight ratio. Although
some aluminium alloys can exhibit good corrosion resistance
when exposed to the environment, the majority of
aluminium alloys have to be protected against corrosion.
Established surface pre-treatment processes, like chromating
and phosphating, are of high economic significance.
Due to high toxicity the use of chromium (VI) is no longer
approved in the automotive and the electronic industries.
Silane based systems are one of the most attractive alternatives
since they are environmentally friendly.
Silanes were originally developed for adhesion promotion.
They can improve the adhesion between inorganic
fillers and organic binders in composites. Silanes can be
used as primers in formulations for better adhesion of
polymers and coatings on inorganic substrates like metals.
Figure 1 shows the improved peel strength of a maleic
acid grafted polyolefin on an aluminium alloy primed with
a silane solution.
and pigments can be a problem, especially when the pH of
the water-borne sol-gel system (Dynasylan® SIVO 160 has
a pH of 4 – 4.5) and e. g. the pH of the polymer dispersion
does not match.
In the following example Figure 2 shows a diluted
Dynasylan® SIVO 160 and a formulated Dynasylan® SIVO 160
solution used for the blank corrosion protection of the
aluminium alloy 5005 used for construction applications.
An untreated panel is used as control.
In Figure 2 it can be seen that after 1000 hours in
the neutral salt spray test only the blank aluminium
alloy 5005 showed corrosion. The samples treated
with the diluted Dynasylan® SIVO 160 solution and the
Dynasylan® SIVO 160 formulation showed less corrosion
or no corrosion after 1000 hours in the salt spray test. In
general, it can be stated for the aluminium alloy 5005:
The diluted Dynasylan® SIVO 160 solution and the
Dynasylan® SIVO 160 formulation do protect against corrosion.
The Dynasylan® SIVO 160 formulation showed the
best performance in the corrosion test.
Dynasylan® SIVO 160 provides excellent adhesion of
the water-borne PUR coating to the aluminium substrate.
The combination of Dynasylan® SIVO 160 and the waterborne
clear coat results in a protective combination, that
is resistant to both moisture and salt corrosion. It should
be mentioned that the water-borne coating based on
VESTANAT® EP-HP 2033 is displaying an excellent
scratch resistance.
200 Hours Humidity Test
Control SIVO 160
coating
SIVO 160
& coating
Medium force in N / 5 cm
NSS 1000 Hours
corrosion
corrosion
corrosion
no corrosion
84
120
Blank
SIVO 160 dilution
SIVO 160
formulation
Figure 3
Test results of coated aluminium alloy 2024 T3 after 200 hours in the humidity
test (100 % RH, 40 °C). Procedure: Cleaning in a mild alkaline solution
(60 °C), followed by by dip coating with a Dynasylan® SIVO 160 dilution:
15.0 % (w / w) Dynasylan® SIVO 160, 0.02 % (w / w) wetting agent all in
dist. water; Curing at 60 °C for 10 minutes, layer thickness:
100 – 150 nm. Water-borne clear top coat: 19.95 % (w / w).
Vestanat® EP-HP 2033, 0.15 % (w / w). BYK 341, 0.1 % (w / w).
Reaxis C 333 (catalyst, Reaxis Ínc.), 79.8 % (w / w). dist. water. Coating was
applied with a blade and cured at 80 °C for 10 min. Dry film thickness: ~ 5 µm
Blank
Silane primer
Figure 1
Peel strength: Aluminium stripes were primed with amino functional silanes.
Primed stripes were bounded with maleic acid anhydride grafted PO at
160 °C. The adhesion was tested in a 180 ° peel test at 20 mm / min.
Silanes are more and more used as additives in the field
of coatings or even as binders. Especially silane based
water-borne sol-gel binders are of interest since they
are environmentally friendly, storage stable, defined and
offer interesting possibilities in the field of corrosion protection
and metal treatment. Dynasylan® SIVO 160 is the
latest development of such a silane based water-borne
sol-gel system. Water-borne silane systems like
Dynasylan® SIVO 160 are fully hydrolyzed, nearly VOCfree
and contain reactive silanol groups which are stabilised.
Therefore Dynasylan® SIVO 160 is a defined product
with constant product quality and performance. The
silanol groups can not just react with the metal substrate
but also with each other in a condensation reaction. When
the condensation reaction takes place, a dense network is
formed at the surface of the aluminium substrate. In some
cases the pure sol-gel system can form a stable layer and
can give a good passive corrosion protection. It is a big
advantage that formulations with Dynasylan® SIVO 160
can be used at low curing temperatures. The cured coating
layer can protect without top coat against corrosion,
whilst simultaneously acting as an adhesion promoter
when any subsequent coating is applied.
In most cases it is necessary to optimise the anticorrosive
properties and the overall performance by formulating
water-borne sol-gel systems. Formulating knowhow
is helpful but in many cases water-borne sol-gel
systems behave differently compared to organic coatings.
Compatibility with additives, polymer dispersions, fillers
corrosion some corrosion no corrosion
Figure 2
Test results of coated aluminium alloy 5005 after 1000 hours neutral salt
spray test. Procedure: Cleaning in a mild alkaline solution (60 °C), followed
by acid pickling followed by dip coating. Dynasylan® SIVO 160 dilution:
12,5 % (w / w) Dynasylan® SIVO 160, 0,02 % (w / w) wetting agent all in
dist. water; Dynasylan®SIVO 160 formulation: 12,5 % (w / w)
Dynasylan® SIVO 160, 0,02 % (w / w) wetting agent, 600 ppm Cr(III),
all in dist. water. Curing for 10 mins at 80 °C; dry layer thickness: 100 – 200 nm
Silane based water-borne sol-gel systems are usually
applied as a thin layer in the nm range. In some cases the
performance of such a thin layer can be limited. In these
cases a top coat should be applied on the sol-gel layer.
Since the cured sol-gel layer already protects the metal
surface the layer thickness of the top coat can be reduced,
depending on the performance that is needed.
If a coating with a high corrosion protection performance
and vapour barrier is requested, water-borne polyurethane
(PUR) coatings can be used together with the
sol-gel coatings as a sustainable solution. The additional
corrosion protection can be important for corrosive substrates
like the aluminium alloy 2024 T3. The excellent
performance of such a combination is shown in Figure 3
after 200 hours in the humidity test.
The blank sample is discolored by corrosion products.
Both, the Dynasylan® SIVO 160 treated plate without
clearcoat as well as the aluminium plate coated only with
a water-borne PUR clearcoat based on VESTANAT® EP-HP
2033 show corrosion. Perfect results could be obtained
with the two layer coating consisting of environmentally
friendly Dynasylan® SIVO 160 and a 5 µm layer of the
water-borne PUR top coat.
The market is looking for alternate corrosion protection
systems since chromate is being phased out
and other surface pre-treatment processes still use
aggressive media and chemicals with a high environmental
impact. Novel water-borne silane sol-gel systems
like Dynasylan® SIVO 160 are very promising solutions
for such applications since they are nearly VOC-free and
environmentally friendly. This kind of silane-based binders
can be modified and formulated in many ways. It can
be combined with environmentally friendly top coats such
as the water-borne based on Vestanat® EP-HP 2033.
For commercial applications a detailed formulation
development and stability testing is required.
Contact Dynasylan® Nafta
kerstin.weissenbach@evonik.com
Contact Vestanat® Nafta
corey.king@evonik.com
Contact Dynasylan® Europe
philipp.albert@evonik.com
Contact Vestanat® Europe
andre.raukamp@evonik.com
Contact Dynasylan® Asia
Helmut.Mack@evonik.com
Contact Vestanat® Asia
qi.fu@evonik.com
Smart Formulating Journal | Issue 9 | April 2012

4
AEROSIL® Fumed Silica for Coating Defoamer
• Hydrophobic AEROSIL® fumed silica is an effective booster silica in defoamer formulations for waterborn coatings.
• Increasing concentrations of hydrophobic AEROSIL® fumed silica products (1 to 2 % by weight) result in better
deaerator / defoamer performance.
• AEROSIL® grades exhibit a better antisettling stability in deaerator / defoamer formulations when more dispersing
energy is applied in their manufacture.
• All hydrophobic AEROSIL® grades are compatible with the tested polyurethane binder system.
• Performance and compatibility of hydrophobic AEROSIL® grades with the examined acrylate / methacrylate and
polyvinyl acetate binder systems improve with increasing hydrophobicity.
Silica in Coating Defoamer
Surfactants are used in modern industrial coating formulations
in order to facilitate dispersion and wetting of
pigments and enhance incorporation of water-insoluble
binders into water-borne paints. An undesired side effect
of surfactants, however, is the stabilization of air bubbles,
incorporated during the manufacture or application of
coatings. Therefore, defoamers are often added in the preparation
of coating formulations. For providing deaeration
as well as defoaming effects, defoamers must exert interfacial
activity. A challenge remains: the defoamer applied
needs to be partly incompatible with the coating formulation
for the desired deaeration / antifoam effect, but must
also be compatible enough with the respective binder system.
Otherwise “fish eyes” and other failures may occur.
The refore, several hydrophobic AEROSIL® fumed silica
grades were compared as part of a standard defoamer
formulation. The designation “R” in the AEROSIL® R
grades indicates surface treated (hydrophobized) fumed
silica. In all experiments a mixture of polyethersiloxanes
(38 % by weight) and white oil Ondina® 913 (60 – 61 %
by weight) was used as a base defoamer formulation.
Different hydrophobized AEROSIL® fumed silica types
were incorporated as defoamer / deaerator booster. We
addressed the question, which physico-chemical parameter
of the silica (e. g. surface area, silanol group density,
C-content, hydrophobicity) influences the settling behav-
Table
Process Parameters Used to Prepare the Defoamer Formulation with
Different Hydrophobic AEROSIL® Grades
Dispersing Energy
Low
(Lab stirrer at 1000 rpm)
Medium
(Dissolver-blade at 2000
rpm)
High
(Ultra-Turrax® at 10.000
rpm)
AEROSIL®
concentration
1 % by weight
1.5 % by weight
2 % by weight
Hydrophobic AEROSIL®
fumed silica investigated
AEROSIL® R 972
AEROSIL® R 104
AEROSIL® R 974
AEROSIL® R 106
AEROSIL® R 805
AEROSIL® R 812
AEROSIL® R 812 S
AEROSIL® R 202
ior, the performance and finally the compatibility the
most.
It is well known that the incorporation of fumed silica
into a defoamer formulation may be critical with regard
to silica concentration and the dispersing energy. In order
to limit the number of defoamer formulations and the
respective application tests a program was set up according
to a design of experiments (DoE). Microscopic and
rheological evaluations accompanied the settling behavior
of the respective AEROSIL® fumed silica product in
the defoamer formulation. In a second step, the defoamer
formulations were applied to three different binder systems.
Air content was evaluated gravimetrically and finally
the flow out test on a polyethylene covered slope was
examined for compatibility, e. g. fish-eyes, spots or other
failures.
Sedimentation Stability of Hydrophobic AEROSIL® Fumed
Silica in Defoamer Formulations
Initially the focus was on the sedimentation stability of
hydrophobic AEROSIL® fumed silica in the defoamer formulation.
Eight different hydrophobic AEROSIL® grades
were dispersed into the defoamer formulation at three
levels of dispersing energy and in three different concentrations
(see table).
The combined results of the visual, microscopic and
rheological evaluations were as expected. They showed
that the highest sedimentation stability of the defoamer
was achieved when using
a) the highest dispersing energy (10 000 rpm,
Ultra-Turrax®) and
b) the highest AEROSIL® concentration (2 % by weight).
The sedimentation stability correlated well with the
hydrophobic nature of the respective fumed booster silica.
AEROSIL® R 972, AEROSIL® R 104 and AEROSIL® R 974
tend to sediment easier (relative score about 70) in the
SILIKOPUR® 8080 –
an Innovative Combination of Polyurethane and Silicone!
SILIKOPUR® 8080 is a one-pack, silicone-modified polyurethane
manufactured using a targeted combination of
silicone and polyurethane components. While polyester
polyol is used in the manufacture of conventional PU
dispersions, hydroxyfunctional organosiloxane is used
in the synthesis of SILIKOPUR® 8080. This gives the
product the unique properties of silicone-containing
compounds.
Coatings based on SILIKOPUR® 8080 are used substantially
on leather, textiles, wood and plastics. They
distinguish themselves principally by a high elasticity
which is retained even at low temperatures.
The coatings also exhibit hydrophobic characteristics
and a non-stick effect. Used in combination with acrylic
binders, the product can improve abrasion resistance.
SILIKOPUR® 8080 can be diluted with water and is
air-drying.
Contact
Dr. Sascha Herrwerth
sascha.herrwerth@evonik.com
Smart Formulating Journal | Issue 9 | April 2012

5
used standard defoamer formulation, whereas the more
hydrophobic fumed silica products AEROSIL® R 812 S and
AEROSIL® R 202 exhibited a better antisettling behavior
(relative score about 80, see figure 1).
Figure 1
Sedimentation Stability of Different Hydrophobic AEROSIL® Fumed Silica Grades
Increasing Hydrophobicity
AEROSIL® R 972
AEROSIL® R 104
AEROSIL® R 974
AEROSIL® R 106
AEROSIL® R 805
AEROSIL® R 812
AEROSIL® R 812S
AEROSIL® R 202
60 70 80 90
Relative Score
Figure 2
Performance and Compatibility of Hydrophobic AEROSIL® Grades in Different Binder Systems
Increasing Hydrophobicity
AEROSIL® R 972
AEROSIL® R 104
AEROSIL® R 974
AEROSIL® R 106
AEROSIL® R 805
AEROSIL® R 812
AEROSIL® R 812S
AEROSIL® R 202
Performance and Compatibility of Hydrophobic
AEROSIL® Grades
The defoamer formulations above were added at three
different defoamer concentrations (0.1 %, 0.175 %, and
0.25 % by weight) to the respective binder system and the
0,8 0,9 1
Relative Score
mixture was stirred for one minute at 3000 rpm (laboratory
stirrer) in order to allow air introduction, followed
by immediate gravimetrical estimation of the air content
and subsequent flow-out test for compatibility evaluation
and scoring.
The defoamer / deaerator performance and compatibility
of the respective defoamer formulation in three different
dispersion systems systems
a) Acrylate / methacrylate (Mowilith® 7717, Celanese)
b) Polyurethane (APU® 1035, Alberdingk-Boley)
c) Polyvinylacetate (Airflex® CEF 10, now Wacker)
was then evaluated and scored. The performance / compatibility
in the polyurethane-dispersion was found
to be very good with all of the tested defoamer formulations
and hydrophobic fumed silica AEROSIL® grades
(APU® 1035, purple columns, all score close to 1, see
figure 2).
In case of the acrylate / methacrylate binder
(Mowilith® 7717, grey columns, score 0.85-0.93) as
well as with the polyvinylacetate – binder system
(Airflex® CEF 10, light purple columns, score 0.89-1.0)
the hydrophobic AEROSIL® grades exhibited a broader
range in their performance and compatibility with the
binder system. It could be seen that the less hydrophobic
AEROSIL® products AEROSIL® R 972, AEROSIL® R 104 and
AEROSIL® R 974 are less compatible with these
binder systems than the more hydrophobic grades,
AEROSIL® R 812 S, AEROSIL® R 8200 and AEROSIL® R 202.
Although the results clearly indicate that in the given
formulation higher hydrophobic AEROSIL® contents
provide better results, it should be mentioned that it is
difficult to predict the behavior of fumed booster silica
in other coating defoamer formulations with regard
to settling and compatibility. Hence it is known that in
other defoamer base formulations, also less hydrophobic
AEROSIL® R 972 and AEROSIL® R 974 are used successfully
in coating defoamer formulations.
Contact
Dr. H.-W. Wollenweber
horst-werner.wollenweber@evonik.com
Mowilith 7717 APU 1035 AirFlexCEF 10
UV Coatings: as Matte as it Gets
When one thinks of eco-friendly coatings, UV-curable
coatings immediately spring to mind. Traditional uses are
for wood and furniture lacquers and printing inks. As we
know, application on plastics and metal substrates is also
significant for coatings such as these.
The gloss of such UV coatings should, of course, be
able to be varied over a large range from high to low gloss
including dull matte finishes. Strong matting is often
required, but dull matte finishes are particularly difficult
to achieve with UV coatings. Increasing the matting
agent content usually leads to undesirable higher viscosities,
yield point anomalies and thixotropic effects and,
consequently, problems during the application process
(e. g. with roll units).
The quality of the coatings surface also leaves much
to be desired because of flow problems or air inclusions.
The solution:
optimal wetting of the surface of matting agents
TEGO® Dispers 688, a new polymeric wetting and dispersing
additive from Evonik, has been developed specifically
for optimal wetting and stabilization of matting agent
surfaces. TEGO® Dispers 688 enables the formulator to
significantly lower the viscosity of the matte formulation.
The yield point of such formulations is also lowered and
thixotropic effects reduced. This results in good matting
and problem-free application. Lowering the yield point
positively affects the flow and degassing of the coating
film. TEGO® Dispers 688 is highly effective on the most
diverse matting agents in UV formulations based on all the
common types of oligomers.
TEGO® Dispers 688 offers the positive effects mentioned
above. It also suppresses the undesirable reglossing
(gloss-up) of the coating which occurs with many other
wetting and dispersing additives.
Contact
Heike Semmler
heike.semmler@evonik.com
Smart Formulating Journal | Issue 9 | April 2012

6
Widening the Scope for Matting
Solvent-Free UV-Cured Coatings
It is relatively easy to produce a matt finish in conventional, solvent-based
coatings as opposed to UV-cured coatings. In extensive testing which has seen
it accomplish groundwork in this field, Evonik has come up with a more effective
way of matting these latter types of coating. The resulting product is a new
matting agent, ACEMATT® 3600, with a special surface treatment. This product
now broadens the options available for the formulation of matt UV coatings.
Model for insufficient matting
Earlier ”gel point”
= high shrinkage efficiency factor
= insufficient roughening
UV radiator
A Simple Model for a Complexity of Correlations
Application engineers at the Evonik have developed a
model for matting UV-cured coatings. Their model illustrates
how the non-materialization of film shrinkage
caused by the absence of solvents can be offset by other
mechanisms.
The first parameter which the developers examined
was particle size of the matting agent. They looked at
two conventional silicas used to create a matt finish. These
silicas had mean agglomerate particle sizes of 4.5 µm and
14.5 µm (in ACEMATT® OK 607and ACEMATT® HK 450,
respectively). Using this simple model which covers the
whole spectrum of particle sizes used in silica-based matting
agents, it is possible to qualify the impact various particle
sizes have. In this model, same-size spherical particles
in the highest possible packing density represent the
silica particles. The agglomerates are evenly distributed
throughout the liquid coating, creating a matting–agent
matrix which does not shrink as much as the binder–agent
matrix surrounding it does during the curing process. The
so-called volume shrinkage of coating during curing is
caused chiefly by the binding agent. The idea the coating
experts had was that it ought to be possible to control
matting to some extent by manipulating the particle size
in the matting agent.
Small Particles for More Efficient Matting in Thick-Layer
UV Coatings
According to the spherical-particles model, if a thick UVcured
coating (< 20 to 25 g / m 2 ) contains a matting agent
whose particles are relatively large (14.5 µm), the volume
shrinkage this produces during curing will result in the
surface of the coating exhibiting only weakly pronounced,
long-wave structures. The surface will be only-moderately
roughened and therefore exhibit only a minimal degree
of matting.
In contrast, finer-particle matting agents containing
particles of 4.5 µm in size will produce a coating-film
surface with a pronounced short-wave structure which
is ideal for the strong diffusion of incident light and thus
produces a high degree of matting (Fig. 1). The result is a
low level of shine at a 60 ° angle.
On the whole, the testing shows that fine silica particles
with mean agglomerate particle sizes of < 5.5 µm
are excellently suited for matting thick-layer UV coatings.
Coarse particle matting agent ACEMATT® HK 450/d50 = 14.5μm
Derived from model
Height difference appr.: 2.0μm
With low roughening and high gloss
at both measurement angels
Values from actual practice
60°-reflectometervalue: 46.1
85°-reflectometervalue: 86.0
Max. roughness profile height Rz: 0.77μm
Arithm. mean roughness value Ra: 0.08μm
Fine particle matting agent ACEMATT® OK 607/d50 = 4.5μm
Devided from model
Height difference appr.: 2.0μm
with higher roughening
Low gloss at 60° measurement angel
High gloss at 85° measurement angel
Figure 1
The surface structures of a thick coating film.
Werte aus der Praxis
60°-reflectometervalue: 22.6
85°-reflectometervalue: 77.8
Max. roughness profile height Rz: 1.20μm
Arithm. mean roughness value Ra: 0.14μm
Large Particles for Thin Layers
When it comes to the matting of thin layers, coating formulators
only gain limited benefit from polymerization
induced volume shrinkage since the layers are simply not
thick enough. For thin layers, therefore, coarser-particle
silica will always be a better choice than fine-particle acid
if the particle size approximately matches that of the layer
thickness.
For this, too, the devised model provides an explanation:
The large particles create a highly pronounced
structure (that is, a significant degree of coarseness) on
the film surface, while fine-particle matting agents create
minimally pronounced structures on thin layers, resulting
in barely any diffusion of incident light (Fig. 2). What this
means for thin coating layers is that the mean agglomerate
of the matting agent will ideally be 0.5 to 1 times the size
of the coating-film thickness.
Coarse particle matting agent ACEMATT® HK 450/d50 = 14.5μm
Derived from model
Height difference: > 2.0μm
with high roughening and low gloss
at both measurement angels
Fine particle matting agent ACEMATT® OK 607/d50 = 4.5μm
Derived from model
Height difference: < 1.0μm
with low roughening and high gloss
at both measurement angels
Figure 2
The surface structure of a thin coating film.
Values from actual practice
60°-reflectometervalue: 31.0
85°-reflectometervalue: 49.2
Max. roughness profile height Rz: 3.92 μm
Arithm. mean roughness value Ra: 0.21μm
Values from actual practice
60°-reflectometervalue: 46.8
85°-reflectometervalue: 83.8
Max. roughness profile height Rz: 0.86 μm
Arithm. mean roughness value Ra: 0.08 μm
New Matting Agent Widens Processing Window
Practice corroborates the test results, as Fig. 1 and 2 illustrates.
Matting can be better produced in thick coating
films using fine-particle silicas, and coarse-particle silica
is better used to create this effect in thin coating layers.
It also becomes clear that the new ACEMATT® 3600,
developed specifically for creating matt finishes for UVcured
coatings and post-treated with polydimethylsiloxan
(PDMS), has a significantly higher matting effect across
practically all layer densities. Given that it was also found
to have a positive influence on the matting agent’s rheological
properties and can therefore be added to the coatings
in a higher concentration, formulators now have a
much broader application window at their disposal.
Different Time Sequences in The Polymerization Process
Affect The Degree of Gloss
Another essential factor in matting is the time sequence
employed in the polymerization process to the point of
gelling (one of the defined time points in the processing
schedule). It is at this point in time that polymerization
of the binding agent has progressed to the stage that the
silica and binding-agent matrixes proceed to jointly shrink
further. From the point of gelling onward the agglomerates
of the matting agent are fixed in the emerging polymer
network and can thus no longer contribute to any
further coarsening. The later the gelling point is reached,
the more pronounced the matting effect will be (Fig. 3).
Model for effective matting
Later ”gel point”
= low shrinkage efficiency factor
= sufficiently high
roughening
Conveyor speed: 6m/min = 3 sec exposure
Reaction start
30 cm
”Gel point”
UV radiator
Reaction end
Figure 3
When the gelling point is reached prematurely, this results in an inadequate
poor degree of coarsening (model pictured at top). A later gelling point
allows time for sufficient coarsening to transpire (model pictured at bottom).
At which point in time the gelling point is reached
depends on a number of thermodynamic and reaction_
kinetic factors. The other components in the formulation
(acrylate oligomers; acrylate monomers and photoinitiators)
therefore also have a substantial impact on the mattability
of UV-cured coatings.
Number of Double Bonds Plays an Important Role
The existence of complex reciprocal dependencies means
it is difficult to make any definite assertions regarding the
mattability of oligomers. Evonik has, however, been able
to prove that the double-bonding density, which, in turn,
is contingent on functionality and molecular mass, is of
particular significance. Generally speaking, we can say
that the higher the double-bonding density of the oligomers,
the greater the mattability of the coating.
Formula for Calculation of the Double-Bonding Density
funtionalityt [DB/ Mol]
[DB]
DB-Density =
relative molar mass [g / Mol] x 1000 [g/ kg Oligomer] = [kg Oligomer]
Experiments with different monomers have shown that
their contribution to the matting effect depends primarily
on their molecular form and turnover rate during polymerization.
The photoinitiator also influences the mattability of
UV-cured coatings chiefly through its absorption maxima.
The actual curing process provides additional scope for
reducing the shine in a coating film, with parameters such
as the type of light source and its emissions spectrum, the
intensity and exposure time, the geometry of the lamps
used, the ambient temperature and type of substrate all
figuring into the equation. Evonik’s application engineers
have looked at these variables, too.
Coating formulation continues to be predominantly a
matter of employing experience and intuition. Evonik’s
analyses do, however, show that it is possible to expressly
fine-tune and coordinate the pertinent process and formulation
parameters and thus significantly improve the
degree of control employable in matting UV-cured coatings.
The new ACEMATT® 3600 now affords formulators
a greater array of options for the matting process.
Contact
Reinhard Behl
reinhard.behl@evonik.com
Rüdiger Mertsch
ruediger.mertsch@evonik.com
Smart Formulating Journal | Issue 9 | April 2012

7
TEGO® AddBond –
the Multitasking Adhesion Promoter!
The TEGO®AddBond product group is an excellent
choice for optimizing the adhesion and cohesion
of coatings with numerous substrates and binders.
TEGO® AddBond products are specialized polyester resins
precisely tailored by the selective use of suitable components.
The tailored molecules have an optimized density
of hydroxy and carboxy functionality to meet user
requirements in solventborne, high-solids and waterborne
systems. Additional properties such as gloss, hard-
ness or flexibility and broad compatibility in different
systems make them multifunctional. As they can be used
in water-borne systems or low-VOC formulations, the
TEGO® AddBond product group also makes a lasting contribution
to modern eco-friendly coatings.
Contact
Heiko Alzer
heiko.alzer@evonik.com
• TEGO® AddBond LTH
(100 % solid resin) is used in solventborne
systems for optimizing hardness, gloss and
adhesion on metals.
• TEGO® AddBond LTW
(60 % in xylene, or TEGO® AddBond LTW-B
60 % in butyl acetate). As a soft, flexible polyester
resin, it is used to improve adhesion on
plastics and metals.
• TEGO® AddBond HS
has a property profile comparable to that of
TEGO® AddBond LTW, but is supplied as a
75 % solution in butyl acetate. It is therefore
preferred in high-solids coatings.
• TEGO® AddBond DS 1300
is an aqueous dispersion and therefore improves
the adhesion on metals and plastics as well as
the flexibility of air- and heat-drying waterborne
coatings.
• TEGO® AddBond 1270
(70 % in sec-butanol) substantially improves
the adhesion on metals and plastics of solventborne
and, after neutralization, of water-borne
coatings.
TEGO® Airex 990 and TEGO® Airex 991
Modern, solvent-free deaerators for the next generation of high-solids coatings
Modern high-solids coatings are formulated with ever
greater solids content. This frequently leads to the
problem of foam during application. Modern 2-pack polyurethane
and 2-pack epoxy formulations, in particular,
often exhibit micro- and macro-foam during airless or
air-assisted airless spray applications. For other application
processes too, finding a really effective and sufficiently
compatible deaerator is frequently a challenge for the
formulator.
a) b)
With TEGO® Airex 990 and TEGO® Airex 991, Evonik
has developed simultaneously two new deaerators to meet
these challenges. Achieving an optimum finish with highsolids
formulations is no problem even in high film build
coatings.
Both deaerators are solvent-free and contain 100 %
active substance. This gives the formulator greater freedom
in the choice of type and amount of solvent in the
coating.
As a compatible deaerator, TEGO® Airex 990 is particularly
suitable for use in non-pigmented high-solids,
high gloss systems. It can also be used in pigmented
or matte paint formulations. Its strength is the balance
between good compatibility and effective deaeration.
TEGO® Airex 990 is suitable for all types of spray
application.
TEGO® Airex 991 is a highly effective deaerator
for pigmented high-solids coatings. Thanks to its outstanding
effectiveness against micro- and macro-foam,
TEGO® Airex 991 can be used in a wide range of high-solids
systems with a special emphasis on airless, air-assisted
airless and roller application.
Both new products are easy to handle, easy to mix in
and do not require special labeling.
Contact
Cornelia Alzer
cornelia.alzer@evonik.com
Heike Semmler
heike.semmler@evonik.com
Figure 1
Transparent high-solids coating, spray-applied on black PMMA
a) with TEGOAirex 990 and b) with reference deaerator
Smart Formulating Journal | Issue 9 | April 2012

8
Liquid Silica Nanocomposites from
Evonik – Scratch Resistance and
Transparency for Coatings Systems
Liquid silica nanocomposites from Evonik are used primarily where coatings are required to exhibit high scratch
and abrasion resistance without sacrificing transparency. Also, these products should be easy to formulate.
Furthermore, secondary properties such as barrier effect, reduced shrinkage during curing and improved
adhesion on substrates with hydroxyl function can be achieved in various coatings systems without compromising
the degree of gloss. The properties can only be achieved by conventional means by using several layers.
Manufacture of silica nanocomposites
Using a modified sol-gel process, it is possible to manufacture
composites from silica nanoparticles and organic resins
which, despite being 50 % w / w filled, are water white.
Starting from water glass, spherical silica nanoparticles,
approximately 20 nm in diameter and with a very
narrow size distribution, can be cultured in an aqueous
environment.
These particles then have their surfaces modified to
permit a stable transfer into their future organic matrix.
The results are transparent products that do not exhibit
any sedimentation.
Improving properties with silica nanocomposites
Silica nanocomposites should be regarded as an additive
to the binder in a coating formulation.
In addition to the main property of scratch and abrasion
resistance while maintaining transparency, silica
nanocomposites improve other properties of the coating.
Thus, they reduce shrinkage during curing and improve
barrier effects.
The particles in the cured film are statistically distributed,
i. e. the average distribution is identical at the surface,
in the middle and at the bottom.
Nanocomposite particle distribution
This is quite different from surface active products
such as waxes or silicone oils which are only effective at
the coating / air interface and thus have only a temporary
effect on scratch and abrasion resistance.
Silica nanocomposites, in contrast, offer permanent
protection as they are firmly bound in the cured film
matrix. Because they are distributed throughout the
whole film, the initial recommendation is 5 to 10 % w / w
relative to the solids of a coating formulation.
The liquid nanocomposites from Evonik also have the
advantage that they only cause a slight increase in the
viscosity of the coating formulation. This is achieved by
customized surface modification of the nanoparticles.
On substrates such as glass and aluminum, the glassy
nanoparticles improve adhesion. This effect is utilized in,
for example, printing on high quality glass bottles.
Silica nanoparticles are also suitable for applications
where a barrier effect is required, especially where
excellent transparency is needed. The barrier effect in an
organic coating is increased by the inorganic silica particles.
Diffusion of oxygen or water vapor is thus significantly
lower when compared to an unmodified clearcoat.
The degree of gloss of the formulation is not affected
by the silica nanoparticles. Unlike surface waxes, which
are added as matting agents, the nanoparticles do not
settle out on the surface but are, as already described,
distributed statistically throughout the entire film. It is
thus possible to obtain coatings with improved hardness,
scratch and abrasion resistance without being restricted
by considerations on the degree of gloss.
Use of silica nanocomposites
Incorporation of the liquid composites is easy. Like standard
binders, the products are thoroughly stirred in
together with the main binder at the start of the production
process. Dispersing or bead milling is unnecessary.
Moderately polar solvents such as xylene or toluene
should not be used alone in formulations. These solvents
are, however, generally very compatible when used in
blends with popular solvents such as esters, ketones and
alcohols.
Certain additives can result in incompatibilities with
silica nanocomposites. These manifest themselves in, for
example, agglomeration, flocculation or increased viscosity
of the coating formulation.
To save laboratory time when developing coatings with
silica nanocomposites, compatibility lists are available
from us on request for the additives most commonly used
with NANOCRYL®, NANOPOX® and NANOPOL®. These
lists give recommendations for the compatibility of additives
with the silica nanocomposites in terms of short- and
long-term shelf-life.
Silica nanocomposites for various coatings systems
Optimized silica nanocomposites have been developed by
Tego for the different curing mechanisms in coatings.
NANOCRYL®, a range of silica nanocomposites in various
commonly used UV-curable acrylate monomers, has
Evonik been specially developed for radical-curing UV
coatings.
Product Overview NANOCRYL®
Name
NANOCRYL®
C 130
NANOCRYL®
C 140
NANOCRYL®
C 145
NANOCRYL®
C 150
NANOCRYL®
C 153
NANOCRYL®
C 155
NANOCRYL®
C 165
Monomer
SiO 2 -content[%
w / w]
Viscosity,
25 °C
50 275 mPa•s
Hexanedioldiacrylate 50 175 mPa•s
Trimethylolpropaneformalacrylate
Tripropyleneglycoldiacrylate
Trimethylolpropanetriacrylate
Ethoxylated trimethylolpropanetriacrylate
Propoxylated glycerinetriacrylate
Alkoxylated pentaerythritoltetraacrylate
50 200 mPa•s
50 3.3 Pa•s
50 1.0 Pa•s
50 1.75 Pa•s
50 2.5 Pa•s
Listing status of individual products available on request.
NANOPOX® materials are manufactured from epoxide
resins and suitable reactive diluents.
Smart Formulating Journal | Issue 9 | April 2012

9
Product Overview NANOPOX I
Product Overview NANOPOX II
Product Overview NANOPOL
Name
NANOPOX®
C 450
NANOPOX®
C 460
SiO 2 -
content
[% w / w] Base resin
EEW
[g / equiv.]
Viscosity
25 °C
40 DGEBA 295 60,000
mPa•s
40 DGEBA/
DGEBF
290 45,000
mPa•s
Characterization
aromatic
aromatic,
crystallizationfree
Name
NANOPOX®
C 620
SiO 2 -
content
[% w / w] Base resin
EEC
Cycloaliphatic epoxy
resin for cationic
UV-curing
EEW
[g / equiv.]
Listing status of individual products available on request.
Viscosity
25 °C
40 4.0 Pa•s
Name
NANOPOL®
C 764
NANOPOL®
C 784
Solvent
SiO 2 -content
[% w / w]
Viscosity
25 °C
Methoxypropylacetate 50 < 50 mPa•s
N-butylacetate 50 < 50 mPa•s
Listing status of individual products available on request.
Listing status of individual products available on request.
These NANOPOX® products can be heat-cured anhydrously,
room-temperature cured with amines, or force
cured.
The product NANOPOX® C 620 is suitable for cationic
UV-curing. NANOPOL® is a solvent-based product which
is universally applicable. It is equally suited for use in
1-pack stoving enamels and in 2-pack PUR or UV coatings.
Contact
Marco Heuer
marco.heuer@evonik.com
High Technology in the Store Cupboard
DYNAPOL® Specialty Coating Resins for Exterior and Interior
Protection of the Classic Food Can
Saturated copolyesters have been used for many years as
binders in the area of packaging. The reason is the “modular
construction system” of polyester chemistry: By an
appropriate choice of monomers and their quantitative
assembly in the formulation of the polyester, the customer
gets exactly the properties he wants. Evonik currently has
about 35 monomers available for synthesis into customized
polyesters. One outstanding feature here is the balance
between flexibility and hardness that can be achieved
by adjusting the formulation. In addition, the copolyesters
are odorless and tasteless, and therefore suitable even for
packaging with direct food contact.
Frequent changes and new trends in the packaging
market have resulted in polyesters, of all the available
binders, increasingly coming into focus due to their excellent
properties. Interest in, and demand for, polyesters in
the packaging market has risen significantly. Under the
DYNAPOL® brand name, Evonik markets copolyesters
used as binders in flexible packaging (film primers, printing
inks), coil coatings (facade elements, refrigerators),
and can coatings (food cans, metal packaging).
On the subject of cans, it is interesting that no less a
personage than Napoleon announced a competition about
200 years ago to find a process for preserving food. The
Evonik’s Coatings & Additives Business Unit ensures reliable protection
against corrosion, wear, and scratching. Under the DYNAPOL® brand name it
markets specialty coating resins that protect metal packaging both externally
and internally.
1
2
winning entry, based on the idea of sealing food in airtight
containers, came from a Parisian confectioner. The thin
metal shell is now well established in many application
areas, from the preservation of food and drink to the storage
of chemical products. The can is tough, heat resistant,
100 percent recyclable, and to be found in every store
cupboard.
The biggest challenge in the area of can coating is the
internal coating of food cans, particularly at the stage
where pre-coated metal plate is shaped into can bodies.
The coating must be flexible enough to withstand the
shaping process without damage. A typical tin can contains
several coating layers, up to three outside and one
inside. The exterior layers protect the can from corrosion
and the color printing of the advertising space from
scratches. “In production, coatings are first applied on thin
tinplate and stoved. The body and lid of the can are then
stamped and formed from the coated metal sheet. The
coating must be sufficiently flexible or it will crack and
flake off. If it’s too flexible, on the other hand, it doesn’t
offer enough hardness and protection,” says Rainer Spittka
of Technical Service, Pre-Coated Metal.
Evonik’s polyester resins, designed with just this balancing
act in mind, offer both optimal protection and high
flexibility. For food cans, the requirements on the exterior
3
4
5
Dynapol in Every Layer
1 Internal seam of the can: A special
DYNAPOL® grade covers the weld
seam of the can.
2 Interior coating of the can: This
protective layer prevents acids in
the food from attacking the metal,
and metal particles from entering
the food.
3 Stamping enamel: The clear white
coating protects the metal against
corrosion and serves as a primer for
pin-sharp printing.
4 Printing can be in any desired color.
5 Overprint varnish protects the print
during sterilization and later against
abrasion and scratching.
coating are particularly high; once filled, the cans face the
next test of their durability: sterilization. To preserve the
food, the packaging must be treated at 130 degrees Celsius
and high pressure in the sterilization chamber. Only if the
exterior coating has come through this step undamaged
is the can ready for sale. And DYNAPOL® is useful inside
the can as well, because most foods contain ingredients
that attack tinplate, such as vinegar, lactic acid, oils, and
salts. If the can contains sauerkraut or chilli, for example,
it must also be protected from the inside. The inner coating
layer prevents the acids in the food from attacking the
metal, and metal particles from entering the food.
The development, testing, and statutory approval of
suitable coating systems for food contact applications
takes several years. This sensitive field of application
therefore uses mainly “classics” such as the high molecular
weight DYNAPOL® L 912 and DYNAPOL® L 952
grades. However, relatively new products such as the
medium molecular weight DYNAPOL® LH 815-05 and
DYNAPOL® LH 318-02 grades have also been successfully
launched on the market.
Contact
Rainer Spittka
rainer.spittka@evonik.com
Smart Formulating Journal | Issue 9 | April 2012

10
American Coatings Show 2012 in Indianapolis
New venue – new look – new concept
Visit us at ACS
Stand 2000
At this year’s American Coatings Show, which is being
held in Indianapolis for the first time, Evonik will be positioning
itself as a creative problem-solver dedicated to
addressing challenges faced by its customers. “We love
your problems” is the slogan for the exhibit. “With this
message, we want not only to advertise ourselves, but
also to open up a dialogue with our customers and discuss
the challenges that may be awaiting them in the future,”
says Dr. Klaus Engel, Chairman of the Executive Board of
Evonik Industries AG.
Evonik’s exhibit, which will be almost 50 percent larger
than in the past, will showcase products and solutions
for the coatings market, including some developed in collaboration
with customers. As well as counters and tables
for discussion with customers, there will be a lounge area
where our visitors can relax for a while. In each area,
products will be presented individually using iPads.
We look forward to discussing new trends and our
product innovations for the coatings market with customers.
And we also look forward to bringing home a range of
new problems to be solved. We love your problems.
Contact
Holger Maasewerd
holger.maasewerd@evonik.com
Dates
Smart Formulating
Trade Fair Appearances 2012
08 – 10 May 2012
American Coatings Show | USA, Indianapolis
13 – 15 September 2012
Paintistanbul | Türkei, Istanbul
02 – 04 October 2012
EuroCoat | Spanien, Barcelona
25 – 27 October 2012
China Adhesives | China, Shanghai
28 – 30 November 2012
ChinaCoat | China, Guangzhou
Imprint
Editor
Evonik Industries AG
Rellinghauser Straße 1 – 11
45128 Essen, Germany
Editorial team
Rainer Lomölder
Wernfried Heilen, Wilfried Robers, Torsten Stojanik
Contact: coatings@evonik.com
Layout / Design
Liebchen+Liebchen Kommunikation GmbH
www.LplusL.de
Frankfurt am Main, Germany
Printed in Germany
Smart Formulating Journal | Issue 9 | April 2012