NACURE® DNNSA Catalysts - King Industries, Inc.

NACURE ® DNNSA Catalysts
This second issue of KAT-NIPS highlights the features of NACURE ® DNNSA, Dinonylnaphthalene
Sulfonic Acid Catalysts.
DNNSA
H 19 C 9
C 9 H 19
SO 3 H
Dinonylnaphthalene (Mono) Sulfonic Acid
(DNNSA) based catalysts for amino thermoset
coatings, adhesives and inks offer formulators
not only the typical catalyst benefit of shorter
cure times at lower cure temperatures resulting
in energy savings, but a number of performance
characteristics and improved film properties
because of their unique chemical composition
and structure.
King was an early pioneer of the use of
DNNSA based catalysts for the cure -
crosslinking of melamine resins in the late
1960’s. Today, King offers five commercial
products including a free acid version and four
latent catalysts using amine and polymeric
blocking technologies and is happy to work
with customers to tailor make specific catalysts.
Standard DNNSA Catalysts
NACURE ® 1051
NACURE ® 1323
Acid Catalyst
Blocked Catalyst
Recommended for use in solventborne
systems, advantages of DNNSA catalysts are:
NACURE ® 1419
Blocked Catalyst
Hydrophobicity
Superior corrosion resistance
Excellent adhesion
Excellent substrate wetting
Strong resistance to telegraphing
Reductions in conductivity
Excellent control of wrinkling
Minimization of the undesirable effects of
catalyst-pigment interactions
These performance attributes have made
King’s DNNSA based catalysts a popular
choice for high bake amino crosslinked systems
such as coil coatings and metal decorating.
.
NACURE ® 1557 Blocked Catalyst
NACURE ® 1953 Blocked Catalyst
TABLE OF CONTENTS
Introduction to DNNSA Catalysts 1
Performance Advantages of DNNSA 2
Standard DNNSA Products 6
Formulating Information 7
Catalyst Selection by Application Chart 8
Contact Information 8
KING DNNSA 2013

DNNSA Performance Advantages
I. Corrosion Resistance
Advantages
The hydrophobic nature of DNNSA catalysts
make them well suited for applications where
corrosion resistance is paramount. Typically
offering superior corrosion resistance compared
to catalysts based on more hydrophilic acid
types, DNNSA catalysts provide excellent
substrate wetting properties.
Photo 1.1
DNNSA vs. DDBDSA
250 Hours Salt Spray (ASTM B117)
Polyester/HMMM Coil Coating
Cure: 25 Seconds @ 325°C, PMT: 235°C
The photograph in the top right (Photo 1.1)
shows the salt fog performance of King’s
DNNSA based NACURE 1419 covalently
blocked catalyst versus a Dodecylbenzene
(DDBSA) blocked catalyst at 250 hours of
exposure. Both catalysts were used at equal
acid equivalency to cure a Polyester/HMMM coil
coating.
Blocked DDBSA
Covalently Blocked DNNSA
As demonstrated in Photo 1.2, similar results
were obtained when NACURE 1323 was
compared to a blocked p-TSA catalyst in a high
solids, polyester/acrylic/melamine coil coating
after 500 hours of salt fog exposure.
Photo 1.2
DNNSA vs. p-TSA
500 Hours Salt Spray
HS Polyester/Acrylic/HMMM
Blocked p-TSA NACURE 1323
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KING DNNSA 2013

Photo 1.3
Resistance to Telegraphing
II. Resistance to Telegraphing
Telegraphing in coatings can be defined as
surface imperfections that amplifies the presence
of contaminants such as fingerprints, oils, solvents
or water spots on the surface of the substrate.
In the photographs shown to the left, resistance to
telegraphing of surface imperfections over oily
substrates is demonstrated. A skin cream
containing oil was applied to the hand and
imprinted onto the steel test panel prior to coating
with a high solids acrylic enamel. As shown, the
DNNSA catalysts improved wetting and reduced
the telegraphing of the metal surface significantly.
p-TSA NACURE 1051
Photo 1.4
DNNSA Vs. DDBSA Adhesion
White Baking Enamel - 15 mins@350°F
Alkyd/HMMM (75:25)
III. Improved Adhesion
DNNSA catalysts provide excellent adhesion
compared to other catalyst types. Photo 1.4 to
the left illustrates that performance advantage
comparing NACURE 1051 acid catalyst to a
straight DDBSA acid catalyst.
Similar results were obtained when the DNNSA
catalyst was compared to other sulfonic acid
catalysts.
DDBSA NACURE 1051
At Equal Acid Equivalency
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KING DNNSA 2013

IV. Excellent
Conductivity
An electrostatic coating process
used by many applicators
utilizes spraying techniques to
apply the coating. The
electrostatic nature of the
coating helps reduce paint
losses and improve coverage of
areas on the substrate that are
hard to reach. An electrostatic
charge is applied to the
atomized particles of paint
exiting the spray gun. The
object that is being coated is
grounded, and the paint
particles are attracted to the
grounded surface.
Conductivity, µmhos
2500
2000
1500
1000
500
0
Sulfonic Acid Conductivity
1000 ppm Acid in DI Water
p-TSA DNNDSA DDBSA DNNSA
Most acid catalysts will have an
influence on the conductive
properties of the coating. Small
levels of polar acids such as
para Toluene Sulfonic Acid can
raise the electrical conductivity
of the coating, and result in
ineffective coverage and poor
surface appearance. Use of
highly conductive acids may
require adjustments in solvents
and other formulation components
to reestablish the
optimum conductive range
required for superior spray and
coverage.
Using a DNNSA acid catalyst
has a much smaller influence
on the coating’s conductivity
and allows more latitude in
reaching the target of
conductive properties needed.
Conductivity, µmho
350
300
250
200
150
100
50
0
Blocked Sulfonic Acid Conductivity
1000 ppm Acid in DI Water
p-TSA DNNDSA DDBSA DNNSA
Amine
Polymeric
The two graphs above show comparisons of DNNSA to more polar
sulfonic acids when diluted in water to 1000 ppm sulfonic acid
content. Unblocked as well as amine or polymeric blocked sulfonic
acids based on DNNSA have lower conductivity values than the
other acid catalysts.
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KING DNNSA 2013

V. Excellent Resistance to Wrinkling
Wrinkling is typically caused by the
film’s surface curing too fast or
disassociation of the volatile amine
when blocked catalysts are used.
Wrinkling problems tend to be more
pronounced at higher cure
temperatures (above 150°C) in such
applications as coil and can coatings.
Photo 1.5
Wrinkling DNNSA Vs. p-TSA
Polyester Clearcoat - 15 mins@150°C
p-TSA NACURE 1051
NACURE DNNSA catalysts provide a
balanced cure profile allowing sufficient
time to release volatile components
and minimize differential cure.
VI. Minimization of Catalyst/Pigment Interaction
Catalyst and pigment interactions can
result in film defects ranging from lower
gloss to loss of catalytic activity on
aging and to increased thixotrophy of
the coating.
In the case of titanium dioxide, special
attention should be given to the
surface treatment of the pigment.
Highly treated surfaces will interact
with the polar sulfonic acid group of the
catalyst, leading to lower surface gloss.
Of all catalyst types, DNNSA catalysts
offer the best resistance to loss of
gloss from catalyst/pigment interaction.
Viscosity Increase, %
Catalyst/Pigment Interaction
30 Day Viscosity Stability @ 50°C - TiO 2
700
600
500
400
300
200
100
Greater % Increase = Less Interaction
As shown in the adjacent graph,
DNNSA has lower loss of catalytic
activity due to reduced catalyst/
pigment interaction.
0
R-900 1 Tiona 595 595 R-960 1 CR-50 3
p-TSA DNNSA
Product of: 1. DuPont 2. Cristal Global 3. Ishihara Corporation
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KING DNNSA 2013

Standard Products Available
To improve storage stability of one component acid catalyzed formulations, acid catalysts are
available in a pre-neutralized or blocked form, using amines or polymer components as blocking
agents. Products listed in the chart below offer:
A good balance of cure, stability and film performance
Faster cure
Excellent solubility and compatibility
Hydrophobicity
Less interaction with basic pigments
DNNSA Straight Acid Catalyst
% Active Diluent(s) Acid # or pH* Minimum Cure**
NACURE 1051 50 2-Butoxyethanol 60-64 125°C
Amine & Polymeric Blocked Catalysts
NACURE 1323 21 Xylene 6.8-7.5 150° C
NACURE 1419 30 Xylene/MIBK NA 150°C
NACURE 1557 25
NACURE 1953 25
Butanol
2-Butoxyethanol
Butanol
2-Butoxyethanol
*pH (1:1 ratio), **Cure schedule: 30 minutes, Resin/Urea (60/40 ratio)
DNNSA Catalysts Offer Broad Solubility
6.5-7.5 150° C
6.5-6.9 150° C
With the exception of water, DNNSA catalysts are soluble in the broadest range of solvents
compared to other catalyst types. For example, while blocked p-TSA and DDNDSA catalysts
have limited solubility in aliphatic hydrocarbons and are not soluble in aliphatic hydrocarbons,
DNNSA catalysts are fully soluble. Similarly, while blocked DDBSA catalysts have limited
solubility in ketones, DNNSA are fully soluble. This characteristics make DNNSA catalysts an
ideal choice for universal solubility independent of solvent type for non-aqueous systems.
Solubility In Common Solvents
Solvent
NACURE
1051
NACURE
1323
NACURE
1419
NACURE
1557
Water I I I
I
Glycols S S S
S
Glycol Ethers S S S
S
Alcohols S S N/R
S
Esters S S S
S
Ketones S S S
S
Aromatic Hydrocarbons S S S
S
Aliphatic Hydrocarbons S S S
S
KEY:
S=Soluble, P=Partially, I=Insoluble, NR=Not recommended
NACURE
1953
I
S
S
S
S
S
S
S
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KING DNNSA 2013

DNNSA Catalyst Use Levels
As with any catalyst, DNNSA catalysts use levels are dependent on a variety of factors and
conditions including cure time and temperature, whether the catalyst is blocked or unblocked,
substrate and film thickness.
The following chart, provides good starting point use levels by type based on a 30 minute cure
schedule for a typical binder resin/HMMM ratio of 75/25 at various cure temperatures. The
percentage of catalyst shown is as supplied based on total resin solids.
Do not over catalyze. Using too much catalyst can be a costly mistake and one that can cause
film properties to suffer significantly.
A ladder study of catalyst levels should be conducted to optimize performance.
Starting Point DNNSA Use Levels
3.5
Catalyst Use Level, % by Weight
3
2.5
2
1.5
1
0.5
0
Blocked DNNSA Catalysts
NACURE 1051
1 2 3 4
125°C 150°C 175°C 200°C
Temperature
N-1051 Blocked DNNSA
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KING DNNSA 2013

Catalyst Selection Chart by Application
Metal Substrates
Inks
Solventborne
Primers
Solventborne
Topcoats - Coil, Appliance
Solventborne
NACURE
1051
NACURE
1419
Best Overall
NACURE
1051
Corrosion
Resistance
NACURE
1323
High
Temperatures
NACURE
1051
Best Overall
NACURE
1323 & 1953
High Bake
Systems
NACURE
1419
Corrosion
Resistance
NACURE
1557
Yellowing
Resistance
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KING DNNSA 2013
For Additional Information
Please visit our web site: www.kingindustries.com
or contact us as shown below.
WORLD HEADQUARTERS
King Industries, Inc.
1 Science Rd.
Norwalk, CT 06852
Phone: 203-866-5551
Fax: 203-866-1268
Email: coatings@kingindustries.com
ASIA-PACIFIC OFFICE
Synlico Tech (Zhongshan) Co., Ltd.
106 Chuangye Building, Kang Le Ave.
Torch Development Zone,
Zhongshan, China
Phone: 86 760 88229866
Fax: 86 760 88229896
Email: alex.he@kingindustries.com
EUROPEAN OFFICE
King Industries, International
Noordkade 64
2741 EZ Waddinxveen
The Netherlands
Phone: 31 182 631360
Fax: 31 182 621002
Email: mg@kingintl.nl
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