formulating high performance coatings with novel adhesion test methods

© The Lubrizol Corporation 2014, all rights reserved

Formulating High Performance Coatings with Novel Adhesion Test Methods

Dr. Yutao Yang

NW Coatings Fest 2014 October 9th, 2014Hood River, Oregon

© The Lubrizol Corporation 2014, all rights reserved2

Outlines

Introduction

- Molecular Adhesion

- Adhesion Mechanisms

- Adhesion Test Methods

Results & Discussion

- Case Study 1: Contact angle and surface free energy

- Case Study 2: Effect of coalescent solvents

- Case Study 3: Effect of particle size and special monomer

- Case Study 4: Effect of elasticity

- Case Study 5: Polymer composition effect

- Case Study 6: Adhesion between a top coat and primers on paper

Summary


Introduction: Cohesion

Work of Cohesion: W = 2 γ1 Bulk properties:

Cohesion => Density

Hardness

Melting point

11

1


Introduction: Adhesion

Work of Adhesion

W = γ1 + γ2 - γ12 Interfacial behavior:

Adhesion => Adsorption

Corrosion

Friction

Wear

1 1

2

2


Introduction: Molecular Adhesion

Van der Waals Forces


Introduction: Adhesion Mechanisms

Molecular Adhesion

Contamination Brownian motion

Roughness effect Cracking mechanism

Elastic deformation Non-elastic deformation

Plasticity of surfaces Non-equilibrium adhesion

Chemical Bonding

Covalent (C-O, C-N) Ionic (M-X)

Hydrogen (X-H…Y) Acid-base Interaction


Evolution of Adhesion Test Methodology

Traditional Standard Test Methods Outputs

ASTM D3359 Tape Test Qualitative Classifications

ASTM D4541 Pull-off Test Breaking Stress

ASTM D3330 Peel Test Peel Adhesion Strength

References: [1] Dickinson, Materials Today, 12, 2009, 46. [2] Dhinojwala, Rev. of Scien. Instru. 73, 2002, 2321.

Introduction: Test Method Development

Nano / Molecular Test Methods Outputs

Nano Indentation with AFM [1] Forces between nano-domains

Sum Frequency Generation Spectrum [2] Molecular interfacial interactions

Practical Novel Test Methods Outputs

Micro-Macro scale at interface Interfacial force or energy



Case Study 1

Contact angle and surface free energy for floor panels

Panel 1 Panel 2 Panel 3 Panel 4 Panel 5 Panel 6 Panel 70

20

40

60

80

100

120

0

5

10

15

20

25

30

35

40

20

3332

35

21

29

24

Wat

er C

onta

ct A

ngle

(deg

)

Surf

ace

Free

Ene

rgy

(mN

/m)



Case Study 2

Effect of coalescent solvents on adhesion

Formulation 1

Formulation 2

Formulation 3

Substrate A

Substrate A

Substrate A

Crosshatch Cut (ASTM D3359)

1B

1B

5B

Surface Tension (mN/m)

53

51

40

Coalescent Solvents

DPM/TPM = 7:3

DPM/TPM = 1:1

DPM/TPM = 3:7

*Coalescent Solvent key:DPM = Dipropylene Glycol Methyl EtherTPM = Tripropylene Glycol Methyl Ether



Case Study 3

Effect of particle size and special monomer on adhesion performance

PolymerContact Angle on

Glass (degree)Adhesion Energy

(mJ/m2)Breaking Stress

(N/m2) Crosshatch Cut

P1 28 ± 1 475 ± 27 3327 ± 1275 3B

P2 24 ± 1 641 ± 36 4688 ± 2068 3B

P3 31 ± 1 187 ± 15 2896 ± 1103 2B

P4 26 ± 1 283 ± 19 4509 ± 1934 3B

(New test method) (ASTM D4541) (ASTM D3359)



Case Study 3

Effect of particle size and special monomer on adhesion performance &

Comparison of adhesion test methods

Polymer 1 Polymer 2 Polymer 3 Polymer 40

100

200

300

400

500

600

700

0

1000

2000

3000

4000

5000

6000

7000

3327

4688

2896

4509

Breaking Stress (ASTM D4541) and Adhesion Energy (New method)

Ad

he

sio

n E

ne

rgy

(m

J/m

2)

Bre

ak

ing

Str

es

s (

N/m

2)



Case Study 4

Effect of elasticity on adhesion for PUD coatings: strong positive correlation

Sample 1 Sample 2 Sample 3 Sample 4 Sample 5 Sample 60

500

1000

1500

2000

2500

3000

0

0.5

1

1.5

2

2.5

3

695851

697

2679

1261

207

Adhesion Energy & Elastic Modulus

Ad

he

sio

n e

ne

rgy

(m

N/m

)

Ela

sti

c M

od

ulu

s (

GP

a)



Case Study 5

Polymer composition effect on paint adhesion performance

Paint 1 Paint 2 Paint 3 Paint 4 Paint 5 Paint 60

1

2

3

4

5

Crosshatch Cut Adhesion of Paints



Case Study 5

Polymer composition effect on paint adhesion performance

Paint 1 Paint 2 Paint 3 Paint 4 Paint 5 Paint 60.0

20.0

40.0

60.0

80.0

100.0

120.0

140.0 Adhesion Energy of Paints

Ad

he

sio

n E

ne

rgy

(N/m

)

Adhesion performance is measured and differentiated with the novel method!



Case Study 6

Adhesion between a top coat and primers on paper substrate

Substrate ~ 100 μm

Primer ~ 25 μm

Top coat ~ 25 μm

Crosshatch cut test is hard to apply!



Case Study 6

Adhesion between a top coat and primers on paper substrate

Primer A Primer B Primer C Primer D Primer E Primer F Primer G0.000

0.100

0.200

0.300

0.400

0.500

Ad

he

sio

n fo

rce

(N

)

Adhesion between top coat and primer

Adhesion performance is measured and differentiated with the novel method!


Summary

• Newly developed adhesion test methods have been applied to coating systems:

- Surface free energy of substrates

- Surface tension of coating liquids

- Adhesion energy of dry coating films on substrates

- Elastic modulus of dry coating films on substrates

- Adhesion forces between top coats and primers

• Newly developed adhesion test methods demonstrate higher resolution

and precision than conventional ASTM methods:

- Enhance the understanding of polymer structure effects on adhesion

- Improve the formulations by detecting the composition effects

- Accelerate the development of polymers and coating formulations


Acknowledgements

The Lubrizol Corporation

Larry SchniedersLee YoungMary Solomon

Thank you!

Questions?

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