paint formulation and latex selection to eliminate
TRANSCRIPT
ARKEMA COATING RESINS
PAINT FORMULATION AND LATEX SELECTION TO ELIMINATE SURFACTANT LEACHING IN LOW VOC PAINTS
NEAL ROGERS, SENIOR PRODUCT
DEVELOPMENT ENGINEER
ARKEMA COATING RESINS
AGENDA
Understanding Surfactant Leaching
Methods to Analyze Surfactant Leaching
● Application Testing
● Analytical Testing
Levers to Pull in Latex Development
Paint Formulation Aspects
Performance Data
UNDERSTANDING SURFACTANT STAINING
Low VOC coatings formulated with
common acrylic latexes are prone to
surfactant staining when applied to
exterior buildings
Painting in low temperature / high
humidity environmental conditions
tends to promote surfactant leaching
A resin technology solution in
combination with proper formulating
strategies are needed to eliminate the
defect
Surfactant staining defect
may be pronounced soon
after painting as shown in
these examples.
UNDERSTANDING SURFACTANT STAINING
Pacific Northwest climate is particularly
welcoming for surfactant leaching
Low Temps < 45°F combined with rel.
humidity > 70% are favorable conditions
for leachate migration
Sources:
https://www.usclimatedata.com/climate/seattle/washington/united-states/uswa0395
https://weather-and-climate.com/average-monthly-Humidity-perc,seattle,United-States-of-America
UNDERSTANDING SURFACTANT STAINING
Staining comes from leachate that migrates outward from an applied
coating system to wet environment
Leachates may include a wide variety of hydrophilic materials found
in a fully formulated coating
● Surfactants: alcohol ethoxylates, polyethylene glycols
● Excess salts
● Biocide and fungicides
Because colorant pigment dispersions contain concentrated amounts
of surfactants, dark tinted paints are more susceptible than white or
light color paints
APPLICATION TESTING TO ASSESS SURFACTANT STAINING
Water droplet test
● Described in ASTM D7190-10: Standard Practice to Evaluate Leaching
of Water-Soluble Materials from Latex Paint Films
● Place water droplets on paint film drawdown at various stages of
drying
● Allow the water to stand for 10 minutes, then tilt up the test panel to
allow the water to run-off
● Once dry, evaluate the runoff area for visible streaking defect
APPLICATION - SURFACTANT LEACHING TESTING
Surfactant leaching (D 7190-05 (2015))
● Phenomenon simulated: visible water streaking with
obvious gloss or color difference, or both
7 Days 1 Day 4 Hours
Rating: 1 ~ 5
Exudate extraction test
● Drawdown test panel is prepared and the weight of dry
coating film is determined prior to testing
● There are several ways to force the exudation. One
variation is to submerge a pre-weighed coated test
panel in water for 1 hour
● Test panel is removed and allowed to dry.
● Test panel is re-weighed to determine % leachate
extracted from the film.
GRAVIMETRIC METHOD
SURFACTANT MIGRATION IN LATEX FILMS HAS BEEN
CHARACTERIZED
In simple systems, surfactant leaching can be easily characterized
● Acrylic latex using sulfonate as polymerization surfactant
● Combination of Atomic Force Microscopy (AFM) and X-Ray
Photoelectron Spectroscopy (XPS) proven to be powerful approach to identifying surfactant enriched on surface
Latex film
surface
Same film
surface
after water
rinse
0.0
1.0
2.0
3.0
4.0
5.0
Surface beforerinse
Surface after rinse Bulk
Na
or S
, %Na
S
HOW DO WE USE THIS APPROACH TO SOLVE A PROBLEM WHERE THE COMPONENTS OF THE SYSTEM ARE NOT WELL KNOWN?
Two commercial paints: “Paint A” and “Paint B”
● Paint A shows less leaching than Paint B in the field
• Confirmed by gravimetric method and physical inspection in our lab
● Qualitative method does not reveal source of leachate and formulations not
completely known.
Paint B
Paint A
Leachates
under
optical
microscope
FILM POROSITY & WATER VAPOR PERMEABILITY OF PAINTS
Paint ID Paint A Paint B
Void area – digital image analysis 11% 23%
WVP (perms) – ASTM D1653 19.0 ± 2.2 29.1 ± 3.2
Paint A Paint B
APPROACH TO DETERMINING NATURE AND SOURCE OF THE
LEACHATE
Chemical analyses of leachates
● Analyses of Inorganics
• Trace metals by Inductively Coupled Plasma-Mass Spectrometry (ICP-MS)
● Analyses of Organics
• Functional groups by FTIR and NMR
• Separation and identification by Liquid chromatography-ElectroSpray Ionization Mass Spectrometry (LC-ESI-MS)
● Components Analyzed:
• Paint A:
- Whole paint, paint serum, dry leachate
• Paint B:
- Whole paint, paint serum, paint base serum, dry leachate
- Latex serum
QUANTITATIVE ANALYSIS OF INORGANIC LEACHATES OF
PAINTS
From ICP it was determined:
• Paint A (better performing) has higher concentration of cations in serum but lower concentration in leachate than paint B, i.e., lower percentage leaching of different cations
• Paint B has much higher concentration of Sodium ions in paint and serum
• Paint A is rich in Potassium salts but lower amounts detected in leachate
From other techniques we determined:
• Paint B has a more complex mixture of organics in the leachate including complex mix of alcohol ethoxylates, biocides and fungicides etc.
General Conclusions
• Consistent with porosity measurements
• Sodium seems to be an issue, other inorganics perhaps not so important
Elements (ppm)
K P Na Total Cations
Serum Paint A 1200 416 631 2598
Paint B 402 ND 1200 1712
Leachate Paint A 511 10 391 945
Paint B 245 ND 842 1103
ICP-MS analysis
of spun-down serum
and dry leachate
SOURCE OF THE SODIUM AND ORGANICS IDENTIFIED IN
“PAINT B” LEACHATE
Na
BIT
Anionic Surfactant
Low MW PEG
alcoholEthoxylate
Biocide/Fungicide/Algeacide
Other unknownwater-solublecompounds
Latex Paint
alcoholethoxylates
alcohol Ethoxylates
Reducing surface leaching requires a holistic approach
Latex modification
Paint reformulation
Analysis of
Serum from paint,
paint base, and
latex
WHAT WERE THE RESULTS AND WHAT WE LEARNED
Latex & Paint Design● Latex designed to improve film
formation and reduce sources
materials contributing to leaching.
● Latex film formation optimized with morphology & particle size.
● Paint formulated to reduce leachate.
Key learnings● A combination of analytical techniques
definitively identified the chemical
origins of leachate
● Deep technical understanding enabled collaborative problem solving
Before After
ARKEMA HAS DEVELOPED A NEW LATEX TO OPTIMIZE
SURFACTANT LEACHING RESISTANCE
100% Acrylic binder for Interior and Exterior Coatings
Properties
Property Typical Value
Total Solids % 52
Weight per Gallon 8.8
pH 8.5
Viscosity, cps <800
Particle Size, μm 0.15
MFFT, °C 16
NEW LATEX PERFORMANCE HAS BEEN EVALUATED ACROSS
A NUMBER OF FORMULATIONS
The next few slides feature a comparison of binders that include those targeting general exterior or masonry applications, featuring a satin or
general semi-gloss and gloss formulations.
MFFT °C % Solids
New Latex 16 52
Masonry Acrylic 1 16 58
Masonry Acrylic 2 12 58
Gloss Acrylic 1 <5 49
Gloss Acrylic 2 24 45
Gloss Acrylic 3 <5 45
NEW LATEX PERFORMANCE: SATIN DEEP BASE
Satin Deep Base Formulation
Tinted with individual low-VOC colorants at 12 fl oz/gal
0
0.5
1
1.5
2
2.5
3
3.5
4
Masonry Acrylic 1 ENCOR 601
% L
ea
cha
te E
xtra
cte
d
Satin Deep Base Surfactant Leaching
Blue Red Green Untinted
• 70% Reduction
in extracted
leachate for an
untinted deep
base
• 40% Reduction
in extracted
leachate when
tinted
SA
TIN
Be
st P
erf
orm
an
ce
New Latex
NEW LATEX PERFORMANCE: SATIN MID BASE
New Latex offers excellent potential for block resistance, scrub resistance and efflorescence resistance
0
1
2
3
4
5
6
7
8
9
10
Masonry Acrylic 1 Masonry Acrylic 2 ENCOR 601
Satin Mid Base - Brown Tint
Block Resistance
Block Resistance Room Temp
Block Resistance 120F
New Latex0
200
400
600
800
1000
1200
1400
Masonry Acrylic
1
Masonry Acrylic
2
ENCOR 601
Satin Mid Base - Brown Tint
Scrub Resistance
0
2
4
6
8
10
12
14
16
Masonry Acrylic 1 Masonry Acrylic 2 ENCOR 601
DE
Co
lor
Ch
an
ge
aft
er
Exp
osu
re
Satin Mid Base - Brown Tint
Efflorescence Resistance
24 Hr DE 7 Day DE
SA
TIN
New LatexNew Latex
NEW LATEX PERFORMANCE: GLOSS WHITE
The new technology may also be formulated in semi-gloss to high
gloss coatings and maintain excellent performance balance
for block resistance and surfactant leaching
0
1
2
3
4
5
6
7
8
9
10
Gloss Acrylic 1 Gloss Acrylic 2 Gloss Acrylic 3 ENCOR 601
Gloss White Block Resistance
Overnight Block RT Overnight Block 120F
50 55 60 65 70 75 80 85 90
Gloss Acrylic 1
Gloss Acrylic 2
Gloss Acrylic 3
ENCOR 601
Gloss @ 60 deg
0
1
2
3
4
5
Water Drop (0-5, 5 = no visible
leaching)
% Leachate 1 Hr Soak
Gloss White Surfactant Leaching
Gloss Acrylic 1 Gloss Acrylic 2 Gloss Acrylic 3 ENCOR 601
Be
st P
erf
orm
an
ce
Be
st P
erf
orm
an
ce
GLO
SS
New Latex
New Latex
New Latex
NEW LATEX PERFORMANCE: SEMI-GLOSS DEEP BASE
0
5
10
15
20
25
30
Gloss Acrylic 1 Masonry Acrylic 1 ENCOR 601
Semi-Gloss Deep Tint:
Konig Hardness, 7 Day Dry
No Tint Dark Blue
0
1
2
3
4
5
6
7
8
9
10
Gloss Acrylic 1 Masonry Acrylic 1 ENCOR 601
Semi-Gloss Deep Tint:
Block Resistance, Overnight Dry
Room Temp, No Tint Room Temp, Dark Blue 120F, No Tint 120F, Dark Blue
New latex matches performance of Acrylic binder technology engineered for
deep tint hardness and block resistance while offering greatly improved
surfactant leaching and water resistance.
Se
mi-
Glo
ss
New LatexNew Latex
NEW LATEX PERFORMANCE: SEMI-GLOSS DEEP BASE
New latex matches performance of Acrylic binder technology
engineered for deep tint hardness and block resistance while
offering greatly improved surfactant leaching and water
resistance.
0
1
2
3
4
5
6
7
Gloss Acrylic 1 Masonry Acrylic 1 ENCOR 601
Semi-Gloss Deep Tint:
% Leachate Extracted, 1-Hour Soak
No Tint Dark Blue
Se
mi-
Glo
ss
Be
st P
erf
orm
an
ce
New Latex
ARKEMA IS ACTIVELY STUDYING KEY RAW MATERIAL SELECTION DRIVERS TO OPTIMIZE PERFORMANCE FOR SURFACTANT LEACHING
Current formulation studies focus on dispersant and
associative thickener choice
Comparing Results at 2 PVC levels
● 20%
● 50%
Dispersant Rheology – HEUR Chemistry
A Hydrophilic KU driver #1 + ICI driver #1
B Hydrophobic #1 KU driver #2 + ICI driver #2
C Hydrophobic #2 Thickener #3
NEW LATEX FORMULATION PARAMETERS
Held TiO2 and Extender type
constant to focus on impacts
to Dispersant/Rheology
modifier choice
Different Coalescent levels
were tested for the different
formulations
● 20 PVC at 4.6% on resin solids
● 50 PVC at 2.5% on resin solids
20 PVC 50 PVC
WPG 10.7 11.7
# TiO2 / 100 Gal 219 245
# Extender / 100 Gal 22 282
% PVC 20 50
% Vol Solids 43 38
SCRUBS AND BLOCK: 20 PVC FORMULA
0
1
2
3
4
5
6
7
8
9
10
A/A A/B A/C B/A B/B B/C C/A C/B C/C
Dispersant/Rheology Combination
Block Resistance: 20% PVC Formulas
Block Room Temp Block Elevated Temp
0%
20%
40%
60%
80%
100%
120%
A/A A/B A/C B/A B/B B/C C/A C/B C/C
3000 Scrubs
Dispersant/Rheology Combination
Scrubs: 20% PVC Formulas
All samples performed well for 1-Day dry time block resistance.
Dispersants A and C were slightly better overall than Dispersant B.
Scrubs was best for sample A/A followed by B/A and B/C.
SURFACTANT LEACHING: 20 PVC FORMULA
All samples rated 4 or 5 for surfactant leaching after overnight dry using water drop test method ASTM D7190.
Formulations using more hydrophobic dispersants B and C showed
lower leachate than dispersant A.
0.0%
0.2%
0.4%
0.6%
0.8%
1.0%
1.2%
1.4%
A/A A/B A/C B/A B/B B/C C/A C/B C/C
Dispersant/Rheology Combination
Collected Leachate, 1-Hr Water Soak:
20% PVC
SURFACTANT LEACHING: 50 PVC FORMULA
Samples made from Dispersant C rated best – 4 or 5 ratings –for surfactant leaching after overnight dry using ASTM D7190.
Dispersants A and B gave 2 and 3 ratings.
Formulations using more hydrophobic dispersants B and C showed lower leachate than dispersant A.
0.0%
0.2%
0.4%
0.6%
0.8%
1.0%
1.2%
1.4%
1.6%
1.8%
A/A A/B A/C B/A B/B B/C C/A C/B C/C
Dispersant/Rheology Combination
Collected Leachate, 1-Hr Water Soak:
50% PVC
NEW LATEX - FLAT TO SEMI-GLOSS
Study Formulations: VOC <10g/L
Exterior Flat White & Deep Base
Exterior Semi-gloss White & Deep Base
• White base tested with standard Universal colorant
(2oz/Gal) & hydrophilic dispersant
• Deep base tested with low-VOC Universal colorant
(12oz/Gal) & hydrophobic dispersant
FLA
TS
em
i-
Glo
ss
NEW LATEX – EXTERIOR FLAT DEEP BASE – AGED GLOSS
ALKYD ADHESION
New Latex provides wet adhesion to alkyd after 4
hour dry. 100% of the coating remaining after cross
hatching and 500 scrub cycles.
FLA
T
Wet Adhesion
over GA (4hr dry) A1 A4 A6
A7 New
Latex
C1 -
Contractor
C2 -
Contractor C3 - DIY C4 -
Standard
C5 -
Standard
C6 -
Standard
C7
Standard
C8 -
Masonry
% remaining after
scrub:0 100 0 100 100 0 100 100 100 100 100 0
Scrubs at Initial
Failure1 >500 1 >500 >500 1 >500 >500 >500 >500 >500 1
Scrubs at Final
Failure3 >500 1 >500 >500 3 >500 >500 >500 >500 >500 2
A1 – Good value acrylic
A4 – High-performance interior/exterior acrylic
A6 – General-purpose acrylic
A7 – New Latex
C – Commercial Paints
NEW LATEX – EXTERIOR FLAT DEEP BASE
CHALKY ALKYD ADHESION
FLA
T
C2 C3New Latex C1 C4 C5
Commercial Flat Deep Base Paints
A4 A5A1 A3 A6Commercial Binder in Lab Paints
New Latex provides excellent 24 hour wet and dry
chalk adhesion.
NEW LATEX – EXTERIOR SEMI-GLOSS WHITE BASE – AGED
GLOSS ALKYD ADHESION
New Latex provides wet adhesion to alkyd after 4 hour dry. 100% of the coating remaining after cross hatching and 500 scrub cycles.
Se
mi-
Glo
ss
Wet Adhesion over GA
(4hr dry) A1 A4 A5 A6
A7 New
Latex
C1 -
Contractor
C2 -
Contractor C3 - DIY
% remaining after scrub: 0 100 100 0 100 100 100 100
Scrubs at Initial Failure 1 >500 >500 1 >500 >500 >500 >500
Scrubs at Final Failure 10 >500 >500 9 >500 >500 >500 >500
A1 – Good value acrylic
A4 – High-performance interior/exterior acrylic
A5 – Self-crosslinking APE-free acrylic
A6 – Legacy general-purpose acrylic
A7 – New Latex
C – Commercial Paints
Exterior Semi-gloss White Base
PVC 20%, VS 40%
Se
mi-
Glo
ss
New LatexL2 A3 A5
Commercial Acrylics in Semi-Gloss FormulationA4 A6
New Latex provides excellent 24 hour wet and dry
chalk adhesion.
Dry
Tape
Pull
Wet
Tape
Pull
Exterior Semi-gloss White Base
PVC 20%, VS 40%
NEW LATEX – EXTERIOR SEMI-GLOSS WHITE BASE – AGED
CHALKY ALKYD ADHESION
ACR’S ACCELERATED DPR CYCLIC TESTING
Samples prepared on aluminum panels, dried overnight
Panels exposed in QUV for 100 hours
Iron oxide slurry drawn down over portion of panel, allowed to sit for a standard two hours
Panels scrubbed with wet sponges for 30 cycles
Excess iron oxide rinsed off under running water
Panels allowed to dry for two hours
Y% brightness readings taken from both sponge paths, averaged.
Staining cycle repeated two more times, recording Y% brightness.
Cyclic DPR testing done to better simulate long-term DPR of coating.
FLA
T
New
Latex
CYLIC ACCELERATED DPR SHOWS GREAT LONG TERM
PERFORMANCE OF NEW LATEX
Exterior Flat White Base
PVC 40%, VS 40%
CYLIC ACCELERATED DPR SHOWS GREAT LONG TERM
PERFORMANCE OF NEW LATEX
Se
mi-
Glo
ss
New Latex
Exterior Semi-gloss White Base
PVC 20%, VS 40%
CYLIC ACCELERATED DPR SHOWS GREAT LONG TERM
PERFORMANCE OF NEW LATEX
L2A1 A3 A4 A5 A6 A7
New Latex
C2
Photos show enhanced dirt pickup resistance
performance for new latex.
Exterior Semi-gloss White Base
PVC 20%, VS 40%
ACR’S ACCELERATED EFFLORESCENCE TEST
Fiber-cement composite board coated with high pH mortar, allowed to dry overnight.
Two coats of tinted test paint applied to sections of the mortar, allowed to dry overnight
Panels placed in Cleveland Humidity cabinet set at 50ºC for 48 hours.
Remove panels and place on a cool surface. Rate the panels for efflorescence on a scale from 0-5, with 5 equal to no efflorescence, 0 equals complete failure
NEW LATEX OUTPERFORMS MANY OF THE FORMULATED
COMMERCIAL PAINTS FOR EFFLORESCENCE RESISTANCE
FLA
T
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
5.0
A1 L2 A3
A4
A5
A6
A7
EN
CO
R 6
01
X8
C1
- C
on
tra
cto
r
C2
- C
on
tra
cto
r
C3
- D
IY
C4
- S
tan
da
rd
C5
- S
tan
da
rd
C6
- S
tan
da
rd
C7
- R
ece
nt
C8
- M
aso
nry
Flat Deep Accelerated Efflorescence Resistance (48Hr)
Be
stP
erf
orm
an
ce
Ne
w L
ate
x
FLA
T
NEW LATEX OUTPERFORMS MANY OF THE FORMULATED
COMMERCIAL PAINTS FOR EFFLORESCENCE RESISTANCE
New
Latex
Paint #7
NEW LATEX SHOWS ROBUST BLOCK RESISTANCE POTENTIAL
Se
mi-
Glo
ss
New
Latex
Exterior Semi-gloss White Base
PVC 20%, VS 40%
SUMMARY
New Arkema resin technology enables architectural coatings formulators to construct low surfactant leaching coating systems.
Polymer and paint manufacturers can work together to define the source of surfactant leaching.
● Focus on reducing all free hydrophilic species in end formulation.
● Latex morphology and structure must enable optimum tight film formation.
Delivers excellent water resistance capabilities balanced with strong block resistance, hardness, and film toughness for interior and exterior coatings.
A strong binder choice for
● Zero and low VOC exterior masonry coatings
● Commercial building re-paint needs
● Interior semi-gloss tint base coatings with robust water resistance
RECOGNITION
Many Arkema colleagues contributed in preparing the contents of this presentation. Especially the following:
Doug Mall
Jeff Schneider
Christine Fortener
Dr. Wenjun Wu