Low VOC Binder Development: Exploration of Morphology and Crosslinking Erin Vogel│ Dow Coating Materials Dow Coating Materials Partha Majumdar, David Conner,

Low VOC Binder Development: Exploration of Morphology and Crosslinking

Erin Vogel│ Dow Coating Materials Dow Coating Materials

Partha Majumdar, David Conner, Yuanqin Liu, Sonya Eberly, Gary W Dombrowski

Western Coatings Symposium, October 25-28, 2015

®Trademark of The Dow Chemical Company

Outline

• Overview of Low VOC Driver

• Key Unmet Needs in Low PVC High Gloss and Deep Tone Space

• Technical Challenges and Approaches

• Investigation of Variables Hard Phase and Crosslinker Level

Crosslinker Level and Binder MFFT

Effect of Particle Size of Binder

• Performance of Optimized Binder

• Summary

2

Low VOC: Continuous Journey over Decades

VOC reduction in architectural paints over time:

• Initially driven by convenience and cost: water clean-up, odor

• Later driven by regulations and social awareness

Source: Coatingstech, Vol 11, No 4, April 2014 ; 2007 ARB SCM for Architectural Coatings; RAL-UZ 102 Low Emission Wall Paints

3

0

200

400

600

800

VO

C G

ram

s/L

ite

r

VOC ContentArchitectural Wall Paint

Low VOC Drive: Regulations and Eco Labels

Source: Adapted from Paint Quality Institute (PQI)

Environmental Agency/Rule CoverageCurrent VOC limit (g/l) by agency for FLAT paints

US EPA National AIM Rule (1999) All US 250

Ozone Transport Commission (OTC) AIM Rules

CT, DE, PA, NY, NJ, DC, VA, ME, NH 100

California Air Resources Board (CARB) All of CA except SCAQMD areas 100

South Coast Air Quality Management District (SCAQMD) Rule 1113

Los Angeles & surrounding basin 50 (2008)

LADCO/MRPO WI, IL, IN, MI, OH N/A

Environment Canada Canada N/A

This independent, nonprofit organization identifies and promotes green products and services and provides certification for EPA’s environmentally preferable purchasing. Have standards for low VOC, anti-corrosive and recycled paints, and adhesives

Develops standards and certifies low emitting interior products. Greenguard offers a specific program for paints and coatings.

MPI has as its vision; a paint & coatings industry that develops and uses paints and coatings with balanced performance, safely and appropriately EVERY TIME!

Offers two levels of certification for paints and coatings – Indoor Advantage and Indoor Advantage Gold. Products must meet strict indoor air quality performance standards to achieve certification, and must be re-examined annually to maintain certification.

4

®Trademark of UL LLC ®Trademark of Scientific Certification Systems, Inc.

Key Unmet Needs in Low PVC High Gloss and Deep Tone Space

5

• Technologies Enabling Lower VOC Potential

• Technologies that Enable Higher Early Hardness

• Improved Tackiness, Block Resistance and Feel Properties

• Alkyd-like Appearance without some of the Drawbacks

• Lower Emphasis Placed on common Broad Wall Properties

Challenges

6

Harder PolymersSofter Polymers

Block/TackDirt Pick UpResistance

Low Temp Film Form.Reduced Coalescent

Flexibility

Standard VOC Conventional Ultra Low VOC

• Excellent Film Formation • Good Properties

Hard Polymer + Solvent

• Excellent Film Formation• Poor Properties

• Poor Film Formation

• Poor Properties

Soft Polymer Hard Polymer

Plasticization

Approach

7

Compositions- Hard/Soft Monomer Choice & Combination

-Functional Monomer/Specialty

Monomer

Process

Unique Polymer Morphology with

Functionality

Hard Stage

Soft Stage

Initiator

Surfactant, etc

Hard Phase and Crosslinker Level

8

Design Outline: Hard Stage Content: Low to High Crosslinker Level: Low to High Center Points

• Crosslinker level has maximum impact on scrub resistance

• Konig hardness effected by hard phase content (primarily). Some impact from crosslinker level

Prediction Profiler

20

24

28

32

Ko

nig

1D

30.8

02

94

2428323640

Ko

nig

7D

38.3

67

65

900

1200

1500

Scr

ub

116

7.4

41

00

.51

De

sira

bilit

y

0.857052

26

28

30

32

33

Hard Phase

1

1.5 2

2.5 3

3

Crosslinker

00

.25

0.5

0.7

5 1

Desirability

Low→High Low→High

Responses Konig-1 Day

Konig-7 Day

Scrub

Factors Prob > F values are shown

Hard phase 0.0095* 0.0039* 0.3105

Crosslinker 0.0957 0.0151* 0.0082*

[(Hard phase) x

(Crosslinker)]

0.3301 0.5320 0.5674

Formulations-White Gloss (20 PVC) No coalescing agent

* Indicates significant factor

Crosslinker Level and Binder MFFTFormulations-White Gloss (20 PVC) : No coalescing agent except High MFFT- (2% Texanol)

• Crosslinker level has an impact on hardness profile-requires at least a threshold level

• Higher MFFT has more impact on Konig hardness at 7 day

Ko

nig

-1d

(se

c) &

Kon

ig-7

d (

sec)

18

21

24

27

30

33

X-link None Low High High

MFFT Low Low High

Konig-1d (sec)Konig-7d (sec)

Pri

nt-

1d &

Pri

nt-

7d

4

6

8

10

X-link None Low High High

MFFT Low Low High

Print-1dPrint-7d

9

Print rating 1 to 10, 10 = best. Embroidery cloth was used

Pri

nt

Re

sis

tan

ce

Ko

nig

Ha

rdn

es

s (

se

c)

Crosslinker Level and Binder MFFT

10

Formulations-White Gloss (20 PVC) : No coalescing agent except High MFFT- (2% Texanol)

• Significant impact on scrub resistance based on crosslinker level

Scr

ub

0

500

1000

1500

MFFT Low Low High

X-link None Low High High

Sc

rub

Cy

cle

s

10

Crosslinker Level and Binder MFFT

11

Formulations-Deep Base: No coalescing agent except High MFFT-(1.5% Optifilm enhancer 400)

• Crosslinker conc. increases Konig hardness and print resistance in deep base.• Coalescing agent had an impact on initial hardness profile in high MFFT.

Print-1d & Print-7d vs. Coatings

Pri

nt-

1d

& P

rin

t-7d

0

1

2

3

4

5

6

7

8

0% D

AAm

1% D

AAm

2% D

AAm

3% D

AAm-Low

MFF

T

3% D

AAm-H

igh M

FFT

Pri

nt-

1d &

Pri

nt-

7d

Print-1dPrint-7d

Konig-1d (sec) & Konig-7d (sec) vs. Coatings

Ko

nig

-1d (

sec)

& K

onig

-7d

(se

c)

12

14

16

18

20

0% D

AAm

1% D

AAm

2% D

AAm

3% D

AAm-L

ow M

FFT

3% D

AAm-H

igh

MFF

T

Ko

nig

-1d

(se

c) &

Konig

-7d

(sec)

Konig-1d (sec)Konig-7d (sec)

X-link None Low High High

MFFT Low Low High

X-link None Low High High

MFFT Low Low High

Pri

nt

Re

sis

tan

ce

Ko

nig

Ha

rdn

es

s (

se

c)

Print rating 1 to 10, 10 = best. Embroidery cloth was used

Crosslinker Level and Binder MFFT

12

Formulations-Deep Base: No coalescing agent except High MFFT-(1.5% Optifilm enhancer 400)

• Significant impact on tack resistance after threshold crosslinker conc. Hard phase content drives tack resistance below threshold crosslinker conc.

• Coalescing agent had an impact on initial tack in high MFFT.

Tack

-1d

(Z

apo

n-g

) &

Tack-

7d

(Z

apo

n-g

)

0

200

400

600

800

1000

Tack

-1d

(Z

ap

on

-g)

& T

ack

-7d

(Z

ap

on

-g)

Tack-1d (Zapon-g)Tack-7d (Zapon-g)

X-link None Low High High

MFFT Low Low High

Higher is better

Tac

k R

es

ista

nc

e (

g)

13

Effect of Particle Size

Connecting Letters Report

LevelSmallMediumLarge

AA

BB

Mean918.87500827.62500731.37500

Levels not connected by same letter are significantly different.

• Decrease in gloss, Konig, and scrub with increasing PS• No significant effect on block and print with increasing PS

Formulations-White Gloss (20 PVC): No coalescing agent

600

700

800

900

1000

1100

Scr

ub

Small Medium Large

Binder PS

All PairsTukey-Kramer

0.05

Overlay Plot

Pro

be T

yp

e

EX

P-4

76

6

30

31

32

33

34

35

36

37

38

Glo

ss-2

0d

eg (

1d

)

14

16

18

20

22

24

Ko

nig

-se

c (1

d)

Overlay Plot

Pro

be T

yp

e

Left Scale: Gloss-20deg (1d)

Right Scale: Konig-sec (1d)

Particle Size

Small Medium Large

Scr

ub

Cyc

les

14

Effect of Particle Size

• Decrease in Konig hardness with increasing particle size and rheology modifier demand

Mean(Konig (sec)-1day) & Mean(Konig (sec)-7 day) vs. Particle size

Ko

nig

(se

c)-1

da

y &

Kon

ig (

sec)-

7 d

ay

6

9

12

15

18

70 80 90 100 110 120 130

Mean(Konig (sec)-1day)Mean(Konig (sec)-7 day)

Mean(Konig (sec)-1day)Mean(Konig (sec)-7 day)

8

9

10

11

12

13

14

15

Ko

nig

(sec)-

1d

ay

3 4 5 6 7 8 9 10Total RM (dry lb/100 gallon)

Summary of FitRSquareRSquare AdjRoot Mean Square ErrorMean of ResponseObservations (or Sum Wgts)

0.8552640.8345870.84028711.11111

9

11

12

13

14

15

16

Ko

nig

(se

c)-7

day

3 4 5 6 7 8 9 10Total RM (dry lb/100 gallon)

Summary of FitRSquareRSquare AdjRoot Mean Square ErrorMean of ResponseObservations (or Sum Wgts)

0.8740210.832028

0.6972713.02222

9

Formulations-Deep Base: No coalescing agent

Particle SizeSmall Medium Large

Ko

nig

Ha

rdn

es

s (

se

c)

Optimized Binder in Deep Base

15

Optimized Binder

Internal Binder A Competitive Binder A

Typical formulation VOC 0 50 0-50

Coalescing agent demand + = +

Gloss = = =

Tack -1day(Zapon/feel) ++ = ++

Tack -7day(Zapon/feel) ++ = ++

Block-1day (RT/Hot) =/+ = =/+

Block-7day (RT/Hot) =/+ = =/+

Print (1d/7d) ++/++ = ++/++

Konig (1d/7d) +/+ = +/+

Colorant amount = 12 oz/gal• Optimized binder shows significantly less leaching of water-soluble materials compared to Competitive

Binder A

“++” = Significantly better, “+” = Better

16

Optimized Binder in White GlossOptimized

BinderInternal

Binder A Competitive

Binder ACompetitive

Binder B

Typical formulation VOC 0-25 50 0-50 0

Coalescing agent demand + = + +

Gloss - = - =

Block-1day (RT/Hot) +/+ = +/+ --/--

Block-7day (RT/Hot) +/+ = +/+ --/--

Print (1d/7d) ++/++ = ++/++ NA

Konig (1d/7d) ++/++ = +/+ NA

Scrub + = + ++

Hydrophobic Stain - = - --

Hydrophilic Stain - = -- --

• Optimized binder shows better dry alkyd adhesion and oil softening resistance compared to Competitive Binder A

“++” = Significantly better, “+” = Better, “-” = Weaker, “--“ = Significantly weaker

17

Leaching of Water-Soluble Materials

ASTM

Method:• Followed ASTM method• Drawdown (7 mil) over black leneta chart• Cured in CTR for 4 hr and 1 day test• Water streaking test• Visual appearance ranking: 1 = best to 6 = worst

Binders Rating in Deep Base Paint

Optimized Binder 1

Competitive Binder A 5

Optimized binder shows less leaching of water-soluble materials compared to Competitive Binder A, especially in deep base

Binders Rating in White Gloss Paint

Optimized Binder 3

Competitive Binder A 5

Exposure Series (October 2014)

18

Optimized Binder Competitive Binder A

Pictures taken in July 2015

Two coats of paint over chalky latex cedar board

Exposure Series (October 2014)

19

Optimized Binder Competitive Binder A

Pictures taken in July 2015

Two coats of paint over yellow pine board

Summary

• Hard phase content and crosslinker level in binder composition drive early hardness development and resistance properties.

• Increase in the particle size of binder can lower hardness and scrub resistance.

• Optimized binder provides exceptional early hardness development, maintains balance of properties, and requires no coalescing agent to formulate deep tone and high gloss paints.

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