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© 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
© The Lubrizol Corporation 2014, all rights reserved3
Introduction: Cohesion
Work of Cohesion: W = 2 γ1 Bulk properties:
Cohesion => Density
Hardness
Melting point
11
1
© The Lubrizol Corporation 2014, all rights reserved4
Introduction: Adhesion
Work of Adhesion
W = γ1 + γ2 - γ12 Interfacial behavior:
Adhesion => Adsorption
Corrosion
Friction
Wear
1 1
2
2
© The Lubrizol Corporation 2014, all rights reserved5
Introduction: Molecular Adhesion
Van der Waals Forces
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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
© The Lubrizol Corporation 2014, all rights reserved7
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
© The Lubrizol Corporation 2014, all rights reserved8
Results & Discussion
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)
© The Lubrizol Corporation 2014, all rights reserved9
Results & Discussion
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
© The Lubrizol Corporation 2014, all rights reserved10
Results & Discussion
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)
© The Lubrizol Corporation 2014, all rights reserved11
Results & Discussion
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)
© The Lubrizol Corporation 2014, all rights reserved12
Results & Discussion
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)
© The Lubrizol Corporation 2014, all rights reserved13
Results & Discussion
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
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Results & Discussion
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!
© The Lubrizol Corporation 2014, all rights reserved15
Results & Discussion
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!
© The Lubrizol Corporation 2014, all rights reserved16
Results & Discussion
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!
© The Lubrizol Corporation 2014, all rights reserved17
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
© The Lubrizol Corporation 2014, all rights reserved18
Acknowledgements
The Lubrizol Corporation
Larry SchniedersLee YoungMary Solomon
Thank you!
Questions?