Powder Polyester Resins for Excellent Corrosion Protection · Powder Polyester Resins for Excellent...
Transcript of Powder Polyester Resins for Excellent Corrosion Protection · Powder Polyester Resins for Excellent...
Powder Polyester Resins for Excellent Corrosion
Protection.
Based on paper by: Dana Ionescu, Gert Dijkstra, Hans Hettinga, Marcel Schutte, Menno Claasen
Robert van den Berg Jeths . Technical Application Manager
Abrafati Sao Paulo 16,17,18 September 2013
A effectively, efficiently and eco-friendly
solution to counter corrosion
Page PIMC Abrafati 16,17,18, September 2013
Content
• Introduction
• Background
• Experimental part
• Application properties and results
• Conclusions
• Value Proposition
Page PIMC Abrafati 16,17,18, September 2013
Corrosion protection is a key requirement for steel in numerous applications
Automotive
Small parts
Metal Furniture
Shelving
Appliances
HV/AC
Construction
ACE
Corrosion
Protection
Key Requirement
in most steel
applications
Page PIMC Abrafati 16,17,18, September 2013 3
Corrosion
• If you are able to
stop the access of
oxygen, water and
other ions to the
metal you provide an
effective barrier
against corrosion
Source: http://www.chem1.com/acad/webtext/elchem/ec7.html
Page PIMC Abrafati 16,17,18, September 2013
Corrosion protection through enhanced coating barrier properties
Corrosion can be controlled by providing a barrier against the passage of
ions and/or oxygen and water.
The lower the permeability of the coating for these species, the better
the barrier properties.
Other important properties to provide an efficient barrier are: Wetting
properties, Mechanical properties & Flexibility.
All the above mentioned properties depend on the coating’s constituents,
the most important in this respect being the resin.
Permeability
of species
hydrophobicity
Surface wetting
substrate
(organic) coating Mechanical
stresses
Page PIMC Abrafati 16,17,18, September 2013
Finding a relation between Electro chemical impedance and Neutral Salt Spray
Testing methods used
• Accelerated test – Neutral Salt Spray (NSS)
According to ISO 9227, performed for 500 & 1000
hours
Progression of corrosion is measured after
damaging the coating
• Electrochemical Impedance
Spectroscopy (EIS)
Electrical resistance of intact coating is measured.
Page PIMC Abrafati 16,17,18, September 2013 6
Methods - EIS • Intact coating: Electrical Impedance Spectroscopy (EIS)
– Electrochemical method
– Impedance resistance of altering current (Z [Ω])
– Capacity (C) of the coating (a.o. layer thickness dependent)
– Barrier properties and indicator for water uptake
– Measured with a Zahner Zennium (COLT Method)
• Storage for 14 day in:
– Humidity chamber
(40 °C / 100% rel. humidity)
– Demi. water (25 °C)
– 5 % NaCl solution (25 °C)
• Recording: (10 mHz – 100 KHz)
– 0 h (baseline)
– 14 d (value)
• Result: Remaining impedance after 14 d
Page PIMC Abrafati 16,17,18, September 2013 7
Methods - NSS
• Damaged coating (controlled way): Neutral Salt Spray (NSS)
• Method: ASTM B117
• Conditions
– 35 °C
– 5 % sodium chloride solution
– 500h (or longer)
• Result:
– Corrosion from creep [mm]
• Substrate: R 46 cold rolled steel
Page PIMC Abrafati 16,17,18, September 2013 8
Effect of cure on coating impedance
Loss of Impedance after 14 days of humidity test
Conclusion: Sufficient cure is very important to reach max impedance
Page PIMC Abrafati 16,17,18, September 2013
T
10
The importance of proper cure
Standard 70:30 Hybrid after 480 hrs NSS
Page PIMC Abrafati 16,17,18, September 2013 11
Effect of resin/crosslinker ratio on EIS
Loss of Impedance after 14 days of humidity test
Conclusion:- Stoichiometric resin/crosslinker ratio is very important to obtain
the best Impedance resistance
- Deviation from stoichiometry (under/over) influences
the impedance negatively
Page PIMC Abrafati 16,17,18, September 2013 12
Effect of resin/crosslinker ratio on NSS
Conclusion: -Stoichiometric resin/cross linker ratio is very important to obtain
the best corrosion resistance
- Deviation from stoichiometry (under/over) influences the corrosion
resistance negatively
- For the influence of the resin/cross linker ratio is a clear correlation
between NSS & EIS
Page PIMC Abrafati 16,17,18, September 2013 13
Effect of PVC on EIS
0
20
40
60
80
100
0.0
5.0
7.5
10.0
12.5
15.0
17.5
20.0
22.5
25.0 0.
05.
07.
510
.012
.515
.017
.520
.022
.525
.0
PVC [%v]
Perc
en
tag
e o
f
ori
gin
al
Imp
ed
an
ce [
%]
Kronos 2160 Blanc fixe Super FLayer thickness:
70 - 80µm
Loss of Impedance after 14 days of 5% NaCl
Conclusion: Too high or too low PVC for TIO2 & Filler results in less barrier
properties
Page PIMC Abrafati 16,17,18, September 2013 14
Effect of PVC - NSS
0
2
4
6
8
10
12
5.0 12.5 25.0 clear coat 5.0 12.5 25.0
Amount of filler / pigment [%v]
co
rro
sio
n c
reep
[m
m]
Kronos 2160 Blanc fixe Super F
Layer thickness:
70 - 80µm
Conclusion:
-Clear coats have a worse corrosion resistance than pigmented coatings
- Increasing amounts BaSO4 fillers & TIO2 have a positive influence
on the corrosion resistance
Page PIMC Abrafati 16,17,18, September 2013 15
Effect of pigment type - EIS
Loss of Impedance after 14 days of 5% NaCl
Conclusion: -Surface treatment of TiO2 pigment can have a large impact
on barrier properties of a coating. Hydrophobic pretreatment of pigments is
bad for the barrier properties of a coating
Page PIMC Abrafati 16,17,18, September 2013 16
Effect of pigment type - NSS
Conclusion: surface treatment of TiO2 pigment can have a large impact
(pos/neg) on corrosion resistance
Page PIMC Abrafati 16,17,18, September 2013 17
Effect of fillers on EIS
0
20
40
60
80
100
Kronos
216
0
Aeroxid
e LE
1 2.
5%
Aeroxid
e LE
1 5.
0%
Aeroxid
e LE
1 7,
5%
Blanc
fixe
Sup
er F
Diam
elia 4
0/10
Albaw
ithe
60
EWO
Porta
ryte
15
Om
yaca
rb 5
GU
Durcal 5
Mar
tinal
ON 3
10
Porta
fill A
40
Micr
o Talc
AT 1
Micr
o M
ica
W1
Lith
opon
e 30
% D
S
Different types of fillers (PVC 13%v)
Perc
en
tag
e o
f
ori
gin
al
Imp
ed
an
ce [
%]
BaSO4 CaCO3 Al(OH)3Layer thickness:
70 - 80µm
Loss of Impedance after 14 days of 5% NaCl
Conclusion:
-Correct filler choice is important for good barrier properties
-CaCO3 & Al(OH) are better for barrier properties than TiO2 and BaSO4
-FeO3 gives very poor barrier properties
Page PIMC Abrafati 16,17,18, September 2013 18
Effect of fillers - NSS
0.0
2.0
4.0
6.0
8.0
Kro
nos 2
160
Aer
oxide
LE 1
2.5
%w
Aer
oxide
LE 1
5.0
%w
Aer
oxide
LE 1
7.5
%w
Blanc
fixe
Sup
er F
Dia
melia
40/1
0
EW
O
Albaw
ithe
60
Bar
ista
r 901
5
Por
tary
te 1
5
Om
yaca
rb 5
GU
Durc
al 5
Mar
tinal O
N 3
10
Por
tafill A
40
Micro
Talc
AT 1
Micro
Mica W
1
Lith
opon
e 30
% D
S
Different filler (PVC 13%v)
co
rro
sio
n c
reep
[m
m]
> 10 mm
Layer thickness:
70 - 80µm
BaSO4 CaCO3 Al(OH)3
Conclusion: -Correct filler choice is important for corrosion resistance
-FeO3 & Talc give very poor corrosion resistance
Page PIMC Abrafati 16,17,18, September 2013 19
Effect of additives - EIS
0
20
40
60
80
100
Byk 3
60 P
Addito
l XL
496
Byk 3
68
Mod
aflow
Pow
der 2
000
Mod
aflow
Pow
der I
II
Resiflo
w PV 8
8
Byk 3
951
P
Ceraflo
ur 9
93
Ceraflo
ur 9
70
Chinam
att 1
200
Different additives
(PVC 5%v Blanc fixe Super F)
Per
cen
tag
e o
f
ori
gin
al I
mp
edan
ce [
%]
flow degassing matting
Layer thickness:
70 - 80µm
Loss of Impedance after 14 days of 5% NaCl
Conclusion: - Flow agents, degassing & matting agents can have a negative
influence on barrier properties of a coating
-Resiflow PV88 & Chinamatt 1200 are very poor for the barrier properties of a
coating
Page PIMC Abrafati 16,17,18, September 2013 20
Effect of additives - NSS
0.0
2.0
4.0
6.0
8.0
10.0
-
Byk 3
60 P
Addito
l XL
496
Byk 3
68
Mod
aflofw
200
0
Mod
aflow
III
Resiflo
w PV 8
8
Byk 3
951
P
Ceraflo
ur 9
93
Ceraflo
ur 9
70
Chinam
att 1
200
Different additives (PVC 13%v)
corr
osi
on
cre
ep [
mm
]
Layer thickness:
70 - 80µm
flowdegassing matting
Conclusion: - Flow agents, degassing & matting agents can have a negative
influence on the corrosion properties of a coating
Page PIMC Abrafati 16,17,18, September 2013 21
Use of anti-corrosive pigments - EIS
0
20
40
60
80
100
0.0 2.5 5.0 7.5 10.0
Amount Shieldex® C 303 [%w]
Perc
en
tag
e o
f
ori
gin
al
Imp
ed
an
ce [
%]
Layer thickness:
70 - 80µm
Conclusion: > 10% shieldex anti corrosion pigment has a negative influence on
the barrier properties of a coating
Page PIMC Abrafati 16,17,18, September 2013 22
Use of anti-corrosive pigments - NSS
0.0
1.0
2.0
3.0
4.0
0.0 2.5 5.0 7.5 10.0
Amount Shieldex C 303 [%w]
co
rro
sio
n c
reep
[m
m]
Layer thickness:
70 - 80µm
Conclusion: In NSS Shieldex appears to have a small positive effect, optimum is
5%, however gloss and mechanical properties are affected > 2.5% added
Page PIMC Abrafati 16,17,18, September 2013
Results – Single layer application non pre-treated R 46
Uralac® P 7604 & Uralac® P 7604 performs significantly better than reference
FBE systems after 500 hours in neutral salt spray (NSS) test according ISO 9227
Page PIMC Abrafati 16,17,18, September 2013 24
Key properties compared to other systems (white Single layer)
Key properties Standard
70/30 Hybrid
Uralac® P
7630 70/30
Standard
95/5 Primid
Pure Epoxy Uralac® P
7604
96/4 Primid
Flow (PCI)* 6 6 6 5-6 5
Impact (5/8” ball) 160 IP 160 ip 160 IP 160 IP 160 IP
Cupping test (ESP) > 8 mm > > 8 mm > 8 mm > 8 mm
Cross cut (Gitterschnitt) Gt0 Gt0 Gt0 Gt0 Gt0
Gloss retention (QUV-B) 50-100 hrs 50-100 hrs 400-500 hrs 50-100 hrs 200-250 hrs
Storage 28 days 40˚C * 9 9 9 n.a. 9
Degassing limit n.a. n.a. 125 µm n.a. 125 µm
Salt spray (NSS) 500 hrs 4-7 mm 1-2 mm 4-5 mm 2-3 mm 2 mm
Humidity, 720 hours n.a. Pass n.a. n.a. Pass
Curing cycle 10 min 180ºC 12 min 180ºC 10 min 180ºC 12 min 180ºC 15 min 180ºC
Page PIMC Abrafati 16,17,18, September 2013
Coated on 2,5 mm bare (un-cleaned) construction steel panels after 500 hrs NSS (DIN 9227)
Pure epoxy Uralac® P 7604
Uralac® P 7604 gives similar performance to pure epoxy on bare steel
In above example corrosion takes places because bare steel is not cleaned
Non coated original panel
Panels in duplo Panels in duplo
Page PIMC Abrafati 16,17,18, September 2013
Same test on grid blasted panels after 500 hrs NSS
Non coated original panel Pure epoxy Uralac® P 7604
Uralac® P 7604 gives similar performance to pure epoxy on grid blasted steel
Much less corrosion, due to proper cleaning of steel by grid blasting
proper cleaning remains important, independent of coating system applied
Panels in duplo Panels in duplo
Page PIMC Abrafati 16,17,18, September 2013
Inter-coat adhesion
28
Conclusion: - Inter-coat adhesion between Corres primer and top coat is
comparable or better than FBE primer and topcoat
Page PIMC Abrafati 16,17,18, September 2013
Conclusions (I)
29
There is a clear correlation between EIS & NSS. To reach
maximum resistance (barrier properties) it is very important to:
1. Cure sufficiently
2. Use stoichiometric resin/cross linker ratio. Deviation (over/under) has
a negative influence
3. Use the correct pigments or fillers. a) Clear coatings have less
resistance compared to pigmented coatings and b) Surface treatment
of the TiO2 has a big influence (Hydrophobic has a negative effect)
4. Use the correct PVC, too high or too low TiO2/Filler results in
decreasing properties
For Cold rolled steel, Uralac® P 7630 is the best primer for corrosion
resistance! (in comparison with primers based on pure epoxy or hybrid system)
Page PIMC Abrafati 16,17,18, September 2013
Conclusions (II)
30
The influence of the powder formulation is crucial. Keep in
mind the following:
1.CaCO3 and Al(OH)3 are better for barrier properties than TiO2 and BaSO4
however FeO3 is worst
2.FeO3 and Talc also have negative influence on corrosion resistance
3.Flow-, degassing- and matting agents can decrease the impedance &
corrosion resistance, resulting in worse barrier properties
4.Resiflow PV-88 and Chinamatt 1200 are negative for the barrier
properties of the coating
5.Addition of > 10% Shieldex (anti-corrosion pigment) shows a decrease in
resistance instead of the expected improvement
5b. 5% has a small positive effect on NSS, however gloss and mechanicals
are affected > 2,5%
6. Inter-coat adhesion between Corres primer and top coat is comparable
or better than FBE primer and topcoat
Page PIMC Abrafati 16,17,18, September 2013
Value Proposition corrosion protective coatings
DSM Paint
producers
Applicators
OEM / Job End users
Eco friendly coating
New business
Sustainable business
Reduce / skip pre-treatment
More secure, more forgiving
Less chemicals and waste
Good performance
Lower total system costs
Uralac® P 7604 Uralac® P 7630 significantly reduces and sometimes
completely eliminates chemical pre-treatment steps. In turn it improves
operational efficiency by:
skipping / reducing the number of chemical pre-treatment steps
reducing the amount of pre-treatment chemicals
reducing process waste
Uralac® Corres adds value throughout the metal coatings supply chain:
Page PIMC Abrafati 16,17,18, September 2013
DSM Paint
producers
Applicators
OEM / Job End users
Epoxy free
Equal performance
Lower system costs
Epoxy free
Equal performance
Reduced delaminating risk
Value Proposition epoxy-free primers
As epoxy-free primer Uralac® P 7604 performs equal to conventional epoxy-
based systems, but with much better environmental footprint, reduced risk of
delaminating between layers and lower system costs:
epoxy-free eco-friendly primer system
good corrosion performance, reduced delaminating risk
lower system costs and less price volatile
Uralac® Corres adds value throughout the metal coatings supply chain:
Page PIMC Abrafati 16,17,18, September 2013
Further Work
• At this moment a program is running to apply the same
technological principles to other powder paint systems.
• Possible next developments:
– a Polyester for TGIC cure
– an outdoor durable Polyester
We will keep you informed!