Hydrolytically Stable Silane
Transcript of Hydrolytically Stable Silane
1
Novel
Hydrolytically
Stable Silane
Additives for
Improving the
Performance of
Waterborne Acrylic
Roof Coatings
Jacob Shevrin
Applied Technology Manager
Evonik Corporation
2021
2
The Importance & Requirements of Cool Roofing
Reduce ambient and indoor air temperatures
Climate change mitigation
Reduce heat island effect
Energy savings
Long-term trend toward reflective roofing
Requirements
ASTM D6083 I & II
Water resistance
Solar reflectance
Stain resistance
Elongation and toughness
Evonik Corporation | CTT 2021 | Novel Hydrolytically Stable Silane Additives for Improving the Performance of Waterborne Acrylic Roof Coatings
3 Evonik Corporation | CTT 2021 | Novel Hydrolytically Stable Silane Additives for Improving the Performance of Waterborne Acrylic Roof Coatings
Effects of Silanes in Roof Coatings Ponding water resistance
Reduce water uptake by 40-70%
Improve wet adhesion up to 40-150+%
Primerless dry adhesion
Up to 40% improvement on difficult substrates
Improved stain resistance
Weatherability & durability
4
Why hasn’t this been done before?
Stability.
5
Hydrolyzable alkoxy groups on silanes are water
reactive
Traditional silanes are shelf-stable in aqueous
dispersion for only days/weeks
Unstable silanes cause viscosity increase and gelling
Increasing hydrolytic stability of alkoxy group increases
shelf stability
methoxy < ethoxy < dialkoxy < oligomeric
Silanes must be reactive enough to improve the final
coating
Increasing hydrolytic stability
Stability of Silanes in Aqueous Dispersions
Organofunctional group
Hydrolyzable
alkoxy groups
Silane Structure
Evonik Corporation | CTT 2021 | Novel Hydrolytically Stable Silane Additives for Improving the Performance of Waterborne Acrylic Roof Coatings
6
Comprehensive Study of Silanes in Waterborne Acrylic Roof Coatings
Elastomeric roof coatings formulas based on
• Waterborne Acrylic Resin
Two silanes ultimately selected for their stability in water
• Amine-functional silane monomer
• Epoxy-functional silane oligomer
Performance testing
• Stability (viscosity v. time at 45C)
• Water resistance (ASTM D471, 7 day immersion)
• Dry & wet adhesion (ASTM C794, 7 day immersion)
• Stain resistance (ASTM D3719, carbon black, iron oxide slurry)
• Physical properties, initial and aged (ASTM D2370, 1000h QUV)
Substrates (aged):
• PVC*, EPDM*, Asphalt^
* Weathered in QUV for 350 hours^Weathered outdoors for 3 months
Stability Adhesion
Water Resistance
Elongation
Stain Resistance
Evonik Corporation | CTT 2021 | Novel Hydrolytically Stable Silane Additives for Improving the Performance of Waterborne Acrylic Roof Coatings
7
Meet the Candidates
Epoxy-functional Silane Oligomer
• Oligomeric, low-monomer epoxy silane
• Colorless and non-yellowing
• 258 – 320 g/L VOC (methanol)
• No hazard label
• TSCA listed
Amine-functional Silane Monomer
Monomeric, amine functional
Dialkoxysilane
Colorless to yellow
443 g/L VOC (ethanol)
Corrosive hazard label
TSCA listed
Properties
Molecular weight g/mol > 2000
Viscosity (25 °C) mPa∙s 700 - 1200
Flash point °C > 93
Amine-functional Silane Monomer Properties
Molecular weight g/mol 191
Viscosity (25 °C) mPa∙s 2
Flash point °C 88
Evonik Corporation | CTT 2021 | Novel Hydrolytically Stable Silane Additives for Improving the Performance of Waterborne Acrylic Roof Coatings
Epoxy-functional Silane Oligomer
R = X = glycidoxypropyl
8
Waterborne Acrylic Roof Coating Formulation
Material SupplierQuantity
(wt%)
Grind
DI H2O - 12.51
Dispersant BASF 0.40
Dispersant ICL Phosphate Specialty 0.12
Calcium Carbonate Huber Engineered Materials 34.95
Titanium Dioxide Chemours 5.83
Zinc Oxide Sigma Aldrich 3.88
Letdown (after 24h sitting)
Waterborne Acrylic
ResinDOW 38.95
Coalescent Eastman 0.58
Biocide DOW 0.17
Aqueous Ammonia Sigma Aldrich 0.08
Propylene Glycol Sigma Aldrich 2.02
Thickener Ashland 0.35
Total 100.00
Procedure
1. Add DI Water to container under low speed
2. Add dispersants to container under low speed
3. Under low speed, add Calcium Carbonate, Titanium Dioxide,
and Zinc Oxide to container
4. Mix at high speed in dispermat for 15 – 30 minutes
5. Return to low mixing speed
6. Add Waterborne Acrylic Resin under low speed
7. Add coalescent under low speed
8. Add biocide under low speed
9. Premix Propylene Glycol and thickener out of container
10. Add Aqueous Ammonia under low speed
11. Immediately add Propylene Glycol + thickener to container
and mix under low speed
12. Post-add 0.22% silane (1% on resin solids)
Evonik Corporation | CTT 2021 | Novel Hydrolytically Stable Silane Additives for Improving the Performance of Waterborne Acrylic Roof Coatings
9
Stability – Silanes in Waterborne Acrylic Resin
• 45C oven, 8 weeks = 12 months at room temp.
• Both silanes relatively stable compared to control
• Unstable silanes (not shown) gelled in 2-4 weeks
0
500
1000
1500
2000
2500
3000
3500
4000
Week 0 Week 1 Week 2 Week 3 Week 4 Week 5 Week 6 Week 8 Week 12
Vis
co
sit
y (
ce
nti
po
ise
)
Control Epoxy-functional Silane Oligomer Amine-functional Silane Monomer
On
e Y
ear
Evonik Corporation | CTT 2021 | Novel Hydrolytically Stable Silane Additives for Improving the Performance of Waterborne Acrylic Roof Coatings
10
Water Resistance - Silanes in Waterborne Acrylic Roof Coating
• ASTM D471 (on aluminum), 7 day immersion
• Epoxy-functional Silane Oligomer reduced water
uptake by >60%
• Epoxy-functional Silane Oligomer prevented
delamination and blistering
• Amine-functional Silane Monomer reduced water
uptake by 40% but still delaminated
• Control gained considerable weight, blistered
Epoxy-functional
Silane Oligomer
+2.8% water
weight gain
Amine-functional
Silane Monomer
+4.4% water
weight gain
Delamination
+7.2% water
weight gain
Control
Blistering
Evonik Corporation | CTT 2021 | Novel Hydrolytically Stable Silane Additives for Improving the Performance of Waterborne Acrylic Roof Coatings
11
Dry and Wet Adhesion to PVC – Silanes in Waterborne Acrylic Roof Coating
0
2
4
6
8
10
12
14
16
18
20
Control Amine-functional SilaneMonomer
Epoxy-functional SilaneOligomer
Epoxy-functional Silane Oligomer increased dry
and wet adhesion to PVC by 40-45%
Amine-functional Silane Monomer did not
increase adhesion to PVC
Dry
Wet
Dry
Wet
Dry
Wet
Ad
he
sio
n (
pli
)
CF CF
CF
CF cohesive failure
AF adhesive failure
MF mixed failure
CFCF
CF
Evonik Corporation | CTT 2021 | Novel Hydrolytically Stable Silane Additives for Improving the Performance of Waterborne Acrylic Roof Coatings
12
Dry and Wet Adhesion to EPDM – Silanes in Waterborne Acrylic Roof Coating
0
1
2
3
4
5
6
7
8
9
10
Control Amine-functional SilaneMonomer
Epoxy-functional SilaneOligomer
Epoxy-functional Silane Oligomer improved wet
adhesion to EPDM by >150%
Control lost over 80% of adhesion to EPDM
when exposed to water
Amine-functional Silane Monomer reduced dry
adhesion and had no effect on wet adhesion
Dry
We
t
Dry
Wet
Dry
Wet
Ad
he
sio
n (
pli
)
AF
AF
CF
CF cohesive failure
AF adhesive failure
MF mixed failure
AF AF
MF
Dry Adhesion
Control
Epoxy-
functional
Silane
Oligomer
Wet Adhesion
Epoxy-
functional
Silane
Oligomer
Evonik Corporation | CTT 2021 | Novel Hydrolytically Stable Silane Additives for Improving the Performance of Waterborne Acrylic Roof Coatings
Control
13
0
2
4
6
8
10
12
Control Amine-functional SilaneMonomer
Epoxy-functional SilaneOligomer
Dry and Wet Adhesion to Asphalt – Silanes in Waterborne Acrylic Roof Coating
Epoxy-functional Silane Oligomer and Amine-
functional Silane Monomer resulted in cohesion
failure compared to control adhesion failure
Amine-functional Silane Monomer improved dry
and wet adhesion to asphalt by >130%
Dry
Wet
Dry
Wet
Dry
Wet
Ad
he
sio
n (
pli
)
AF
CF
CFCF cohesive failure
AF adhesive failure
MF mixed failure
AF
CF
CF
Dry Adhesion Wet Adhesion
Evonik Corporation | CTT 2021 | Novel Hydrolytically Stable Silane Additives for Improving the Performance of Waterborne Acrylic Roof Coatings
Epoxy-
functional
Silane
Oligomer
Epoxy-
functional
Silane
Oligomer
ControlControl
14
Contact Angle – Silanes in Waterborne Acrylic Roof Coating
1000h QUV
Silanes have minimal effect on surface contact
angle in waterborne acrylic roof coating
64
65
66
67
68
69
70
71
72
73
Control Amine-functional SilaneMonomer
Epoxy-functional SilaneOligomer
Co
nta
ct
An
gle
(°)
Initia
l
Aged
Initia
l
Ag
ed
Initia
l
Aged
Evonik Corporation | CTT 2021 | Novel Hydrolytically Stable Silane Additives for Improving the Performance of Waterborne Acrylic Roof Coatings
15
Stain Resistance – Silanes in Waterborne Acrylic Roof Coating
Epoxy-functional Silane Oligomer and Amine-
functional Silane Monomer both resisted
staining more than coating made without silane
ControlAmine-functional
Silane Monomer
Epoxy-functional
Silane Oligomer
Evonik Corporation | CTT 2021 | Novel Hydrolytically Stable Silane Additives for Improving the Performance of Waterborne Acrylic Roof Coatings
Carbon
Black
Red Iron
Oxide
16
Elongation – Silanes in Waterborne Acrylic Roof Coating
1000h QUV
Silane did not affect initial elongation
Coatings with Amine-functional Silane
Monomer & Epoxy-functional Silane Oligomer
retained more elongation after aging
0
20
40
60
80
100
120
140
160
Control Amine-functional SilaneMonomer
Epoxy-functional SilaneOligomer
Initia
l
Aged
Initia
l
Aged
Initia
l
Aged
Elo
ng
ati
on
at
bre
ak
, %
Evonik Corporation | CTT 2021 | Novel Hydrolytically Stable Silane Additives for Improving the Performance of Waterborne Acrylic Roof Coatings
17
Tensile Strength – Silanes in Waterborne Acrylic Roof Coating
1000h QUV
Epoxy-functional Silane Oligomer increased
initial & aged tensile strength by 20-30%
Amine-functional Silane Monomer reduced initial
tensile strength that was regained upon aging
0
0.5
1
1.5
2
2.5
3
3.5
4
Control Amine-functional SilaneMonomer
Epoxy-functional SilaneOligomer
Initia
l
Aged
Initia
l
Ag
ed
Initia
l
Aged
MP
a
Evonik Corporation | CTT 2021 | Novel Hydrolytically Stable Silane Additives for Improving the Performance of Waterborne Acrylic Roof Coatings
18
Coating Appearance, Aged – Silanes in Waterborne Acrylic Roof Coating
1000h QUV on aluminum panels
All coatings were free of defectsControl Amine-functional
Silane Monomer
Epoxy-functional
Silane Oligomer
Evonik Corporation | CTT 2021 | Novel Hydrolytically Stable Silane Additives for Improving the Performance of Waterborne Acrylic Roof Coatings
19
Silanes for Acrylic Roof Coatings
Resist ponding water
• Reduce water uptake 60-70%
• Increase wet adhesion to EPDM 130-150%
• Increase wet adhesion to PVC 20-45%
• Prevent delamination and blistering
Reduce staining
• Improve removal of carbon black and iron oxide
Increase durability
• Better flexibility and tensile strength
• Improve weather resistance
Shelf stable
Immediately available & TSCA listed
Evonik Corporation | CTT 2021 | Novel Hydrolytically Stable Silane Additives for Improving the Performance of Waterborne Acrylic Roof Coatings
20
Contact Evonik Silanes
Jacob Shevrin
Applied Technology Manager, North America
+1 732-981-5004
Disclaimer
This information and all further technical advice are based on our present knowledge and experience. However, it implies no liability or other legal responsibility on our
part including with regard to existing third party intellectual property right, especially patent rights. In particular, no warranty, whether express or implied, or guarantee of
product properties in the legal sense is intended or implied. We reserve the right to make any changes according to technological progress or further developments.
The customer is not released from the obligation to conduct careful inspection and testing of incoming goods. Performance of the products described herein should be
verified by testing, which should be carried out only by qualified experts in the sole responsibility of a customer. Reference to trade names used by other companies is
neither a recommendation, nor does it imply that similar products could not be used.
Evonik Corporation | CTT 2021 | Novel Hydrolytically Stable Silane Additives for Improving the Performance of Waterborne Acrylic Roof Coatings
21