Coatings Technology Handbook Episode 1 Part 3 docx

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6

Adhesion Testing

6.1 Fundamentals of Adhesion

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6.2 Standardization of Adhesion Tests

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6.3 Delamination Procedures

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6.4 Local Debonding Systems

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6.5 Flaw Detection Methods

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6.6 Outlook

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References

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6.1 Fundamentals of Adhesion

Without sufficient adhesion, a coating of otherwise excellent properties in terms of resistance to weather,
chemicals, scratches, or impact would be rather worthless. It is therefore necessary to provide for good
adhesion features when paint materials are formulated. There must also be adequate means for controlling
the level of adhesion strength after the coating has been spread and cured on the substrate. Moreover,
methods should be available that allow for the detection of any failure in the case of the dissolution of
the bond between coating and substrate, under any circumstances whatsoever.

6.1.1 Components at the Interface

In chemical terms, there is a considerable similarity between paints on one side and adhesives or glues
in this chapter to concentrate on the behavior of paint materials. Adhesion is the property requested in
either case, though perhaps with different emphasis on its intensity, according to the intended use.
Such a coating is, in essence, a polymer consisting of more or less cross-linked macromolecules and
a certain amount of pigments and fillers. Metals, woods, plastics, paper, leather, concrete, or masonry,
to name only the most important materials, can form the substrate for the coating.
It is important, however, to keep in mind that these substrate materials may inhibit a rigidity higher
than that of the coating. Under such conditions, fracture will occur within the coating, if the system
experiences external force of sufficient intensity. Cohesive failure will be the consequence, however, if the
adhesion at the interface surpasses the cohesion of the paint layer. Otherwise, adhesive failure is obtained,
indicating a definite separation between coating and substrate.

Ulrich Zorll

Forschungsinstitut für Pigmente and
Lacke

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Components at the Interface • Causes of Failure • Measures of
Cross-Cut Test • Tensile Methods
Adhesion
Scratch Technique • Indentation Debonding • Impact Tests
Ultrasonic Pulse-Echo System • Acoustic Emission Analysis •
Knife-Cutting Method • Peel Test • Blister Method
Thermographic Detection of Defects
on the other (Figure 6.1). Both materials appear in the form of organic coatings; thus, it is appropriate

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Coating Calculations

7.1 Introduction

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7.2 Resins

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7.3 Pigments

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7.4 Solvents

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7.5 Additives

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7.6

7.7 Calculations

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7.8 Converting to a 100 Gallon Formulation

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7.9 Cost

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7.10 Coverage

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7.11 Computer Use

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Bibliography

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7.1 Introduction

Coatings are defined as mixtures of various materials. The questions arise as to how much of which
materials, and how do these things relate. The materials fall into four general categories, as follows:
•Resins
• Pigments
•Solvents
•Additives

7.2 Resins

These are the generally solid, sticky materials that hold the system together. They are also called binders,
and when in a solvent, they are the vehicles for the system. They may come as a “single-package” or “two-
package” system. Single package is just the liquid resin or the resin in solvent. Two package means that
an “A” part was blended with a “B” part to cause a chemical reaction. In both systems, we need to know
the amount of solid resin present. This dry material divided by the total of the dry plus the solvent is
frequently called a “resin solid.” With the two-package systems, we need to know not only the solids but
also the ratio of these solids to form the desired film. This ratio may be designated as a simple ratio of
1 to 1. Or it may be based on 1 or 100, as 0.3 to 1, or 30 parts per hundred, or a total of 100 as 43 to
57. These ratios determine the film properties. We will also need to know the density (weight per unit
volume, usually as pounds per gallon) of the resin or vehicle to help calculate volume.

Arthur A. Tracton

Consultant

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© 2006 by Taylor & Francis Group, LLC
Formulation Weight • Formulation Volume • Formulation
Density • Formulation of “Nonvolatile by Weight” •
Ratio (Weight) • Pigment Volume Content (Volume)
Conventions
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Formulation “Nonvolatile by Volume” • Pigment to Binder

Coating Calculations

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TA B LE 7.1

Paint Formulation Calculations

No.

Constants

Calculations
Material lb/gal gal/lb %NV Cost, $/lb Weight Volume Dry Weight Dry Volume #/100 gal gal/100 gal Cost/gal

1Titanium Dioxide 34.99 0.029 100 $1.15 100 2.86 100 2.86 196.00 5.6 2.25
2 Phthalocyanine Blue 12.99 0.077 100 $10.55

50 3.85 50 3.85 98.00 7.5 10.34
3Acrylic Resin Solution 9.05 0.11 50 $1.09 300 33.15 150 16.58 588.00 65.0 6.41
4Toluene 7.55 0.132 0 $0.28 20 2.65
0
0.0 39.20 5.2 0.11
5Butoxyethanol 7.51 0.133 0 $0.75 30 3.99
0 0
.0 58.80 7.8 0.44
6Methyl Ethyl Ketone 6.71 0.149 0 $0.55 30 4.47 0 0
.0 58.80 8.8 0.32
7
8
9
10
Total X X X X 530 50.97 300 23.29 1038.8 99.9 19.88
Factor = 1.96
On Total Formulation
a% Nonvolatile Weight 56.60
b% Nonvolatile Volume
45.69
c Pigment/Binder Ratio
2 to 3
d Pigment Volume Content
28.81
eDensity, lb/gal
10.4
fsquare feet/gal @ 1 mil dry
733

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© 2006 by Taylor & Francis Group, LLC

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Coatings Technology Handbook, Third Edition

TA B LE 7.2

Paint Formulation

Constants

Calculations
No.Material lb/gal gal/lb %NV
%
Solvent
%
Water
Cost,
$/lb Weight Gallons Dry Wt Dry Vol #/100 gal gal/100#
Cost/
100 gal Water Solvent

1 Gloss Varnish 8.43 0.118623962 1 0 0 $0.00 75 8.896797153 75.00 8.896797153 347.76 41.25 $0.00 0 0
2Resin @ 40% in BCarbAc 8.71 0.114810563 0.4 0.6 0 $0.00 25 2.870264064 10.00 1.148105626
115.92 13.31 $0.00 0 69.55284525
3Titanium Dioxide 10.5 0.095238095 1 0 0 $0.00 95 9.047619048 95.00 9.047619048
440.50 41.95 $0.00 0 0

4Antiskin Agent 13 0.076923077 1 0 0 $0.00 0.1 0.007692308
0.10 0.007692308 0.46 0.04 $0.00 0 0
5Butyl Carbitol Acetate 10.8 0.092592593 0 1 0 $0.00 7.4 0.685185185 0.00 0 34.31 3.18 $0.00 0 34.31273699
6Cobalt Drier, 6% 17.83 0.05608525 0.5 0.5 0 $0.00 0.253 0.014189568 0.13 0.007094784
1.17 0.07 $0.00 0 0.586562328
7Lead Drier, 12% 8.5 0.117647059 0.5 0.5 0 $0.00 0.379 0.044588235
0.19 0.022294118 1.76 0.21 $0.00 0 0.878684278
8
0.00 0 0.00 $0.00 0 0
9
0.00 0 0.00 $0.00 0 0
10
0.00 0 0.00 $0.00 0 0
Total X X X X X 203.132 21.56633556 180.42 19.12960304 941.89 100.00 $0.00 0 105.3308289
Total Formulation
factor = 4.63685635 cost/gal
lb/gal 9.42
$0.00
% Nonvolatile weight
88.817
% Nonvolatile volume
88.701 for loss $@95$
Pigment/Binder Ratio 0.51
$0.00
wt pigment 95
wt binder 90
Pigment Volume Content 0.22
vol pigment 2.87
vol binder 10.05
vol pigment + binder

% Water 0.00 VOC = 1.05 lbs/gal
% Solvent 11.18

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© 2006 by Taylor & Francis Group, LLC

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Infrared Spectroscopy

of Coatings

8.1 Introduction

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8.2 Principles

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8.3

8.4 Data Collection

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8.5 Data Interpretation

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8.6 Applications

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References

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8.1 Introduction

Infrared (IR) spectroscopy is a most useful technique for characterizing coatings, a very cost-effective
and efficient means of gathering information. If not the final answer, IR studies can point the way to
other information or techniques needed to solve a problem. Ease of sample preparation is one advantage
of IR. There are numerous ways of presenting the coating sample to the infrared spectrometer. The wide
variety of sampling accessories or attachments, which can easily be swapped in and out of most spec-
trometers, enables the study of liquids and solids under a wide range of conditions. There is large body
of literature on infrared methodology,

1,2,3

and there are extensive collections of reference spectra available.
Almost all components of coatings can be identified by IR; it is especially useful for polymers. IR
spectroscopy can monitor changes, such as drying, curing, and degradation, which occur to coatings.
Quality control of raw materials and process monitoring during coating synthesis and formulation can
be done by IR spectroscopy.
Most important to the identification of coatings and the study of their properties is the skill of the
analytical scientist. This factor is often overlooked because the trend in analytical instrumentation in recent
years has been increasing computer control and automation. Even when these systems are at hand, they
have little value without a well-trained and experienced analytical scientist behind them. The individual
with a coatings problem or application is well advised to seek the services of an experienced spectroscopist.

8.2 Principles

The atoms of any molecule are continuously vibrating and rotating. The frequencies of these molecular
motions are of the same order of magnitude (10

13

to 10

14

cycles per second) as those of IR radiation.
When the frequency of molecular motion is the same as that of the IR radiation impinging on that

Douglas S. Kendall

National Enforcement

Investigations Center, U.S.
Environmental Protection Agency

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Infrared Microscopy • Imaging
Separation • Transmission Spectra • Attenuated Total
Depth Profiling • Other Sampling Methods
Instrumentation
8-2
Reflectance (ATR) • Infrared Photoacoustic Spectroscopy and
8-8 Coatings Technology Handbook, Third Edition
38. D. Lin-Vien, N. B. Colthup, W. G. Fateley, and J. G. Grasselli, The Handbook of Infrared and Raman
Characteristic Frequencies of Organic Molecules. New York: Academic Press, 1991.
39. B. J. Kip, T. Berghmans, P. Palmen, A. van der Pol, M. Huys, H. Hartwig, M. Scheepers, and D.
Wienke, Vib. Spectrosc., 24, 75 (2000).
40. J. R. Ferraro and K. Krishnan, Eds., Practical Fourier Transform Infrared Spectroscopy: Industrial
and Laboratory Chemical Analysis. New York: Academic Press, 1989.
41. B. Schrader and D. Bougeard, Eds., Infrared and Raman Spectroscopy: Methods and Applications.
Weinheim, Germany: VCH Publishers, 1995.
42. W. Sueteka and J. T. Yates, Surface Infrared and Raman Spectroscopy: Methods and Applications.
New York: Plenum Press, 1995.
43. A. M. Millon and J. M. Julian, in ASTM Spec. Tech. Publ., Anal. Paints Relat. Mater., STP 1119, 173
(1992).
44. J. K. Haken and P. I. Iddamalgoda, Prog. Org. Coat., 19, 193 (1991).
45. S. V. Compton, J. R. Powell, and D. A. C. Compton, Prog. Org. Coat., 21, 297 (1993).
46. R. L. De Rosa and R. A. Condrate, Glass Researcher, 9, 8 (1999).
47. A. R. Cassista and P. M. L. Sandercock, J. Can. Soc. Forensic Sci., 27, 209 (1994).
48. J. A. Payne, L. F. Francis, and A. V. McCormick, J. Appl. Polym. Sci., 66, 1267 (1997).
49. G. A. George, G. A. Cash, and L. Rintoul, Polym. Int., 41, 162 (1996).

50. J. L. Gerlock, C. A. Smith, E. M. Nunez, V. A. Cooper, P. Liscombe, D. R. Cummings, and T. G.
Dusibiber, Adv. Chem. Ser., 249, 335 (1996).
51. A. A. Dias, H. Hartwig, and J. F. G. A. Jansen, Surf. Coat. Int., 83, 382 (2000).
52. R. J. Dick, K. J. Heater, V. D. McGinniss, W. F. McDonald, and R. E. Russell, J. Coat. Technol., 66,
23 (1994).
53. M. W. Urban, C. L. Allison, G. L. Johnson, and F. Di Stefano, Appl. Spectrosc., 53, 1520 (1999).
54. D. J. Skrovanek, J. Coat. Technol., 61, 31 (1989).
55. M. L. Mittleman, D. Johnson, and C. A. Wilke, Trends Polym. Sci., 2, 391 (1994).
56. M. Irigoyen, P. Bartolomeo, F. X. Perrin, E. Aragon, and J. L. Vernet, Polym. Degradation and
Stability, 74, 59 (2001).
57. H. Kim and M. W. Urban, Polymeric Mater. Sci. and Eng., 82, 404 (2000).
58. B. W. Johnson and R. McIntyre, Prog. Org. Coat., 27, 95 (1996).
59. M. R. Adams, K. Ha, J. Marchesi, J. Yang, and A. Garton, Adv. Chem. Ser., 236, 33 (1993).
60. L. J. Fina, Appl. Spectrosc. Rev, 29, 309 (1994).
61. T. Buffeteau, B. Besbat, and D. Eyquem, Vib. Spectrosc., 11, 29 (1996).
62. N. Dupuy, L. Duponchel, B. Amram, J. P. Huvenne, and P. Legrand, J. Chemom, 8, 333 (1994).
63. M. W. C. Wahls, E. Kentta, and J. C. Leyte, Appl. Spectrosc., 43, 214 (2000).
64. J. E. Dietz, B. J. Elliott, and N. A. Peppas, Macromolecules, 28, 5163 (1995).
65. T. A. Thorstenson, J. B. Huang, M. W. Urban, and K. Haubennestal, Prog. Org. Coat., 24, 341 (1994).
66. B. W. Ludwig and M. W. Urban, J. Coat. Technol., 68, 93 (1996).
67. E. Kientz and Y. Holl, Polym. Mater. Sci. Eng., 71, 152 (1994).
68. G. C. Pandey and A. Kumar, Polym. Test., 14, 309 (1995).
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© 2006 by Taylor & Francis Group, LLC

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Thermal Analysis
for Coatings

Characterizations

9.1 Introduction

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9.2 Characteristics

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9.3 Techniques

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9.4 Applications

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Bibliography

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9.1 Introduction

The evaluation of substances and finished materials by thermal analysis will be discussed as a tool that
the paint chemist can use to help evaluate coating properties. These properties are those that change as
a function of temperature.

9.2 Characteristics

Substances change in a characteristic manner as they are heated. Thermal analysis (TA) monitors these
changes. TA procedures are generally used to characterize various substances and materials that change
chemically or physically as they are heated. These changes in properties as a function of temperature
have been used to help characterize the interrelationship of a coating’s composition and performance.
TA methods or techniques measure changes in properties of materials as they are heated or at times cooled.
A TA evaluation entails subjecting a small sample of from a few milligrams to 100 mg to a programmed
change in temperature. The resulting change in property is detected, attenuated, plotted, and measured
by a recording device.
The instrumentation consists of an analysis module, a heating or cooling source, a measuring device,
and a system for reporting the results, usually as an

X

–

Y

plot. A computer is used to program and control
the procedure and analyze and store the results.

9.3 Techniques

The techniques of prime importance in coatings’ characterization and analysis include differential scan-
ning calorimetry (DSC), differential thermal analysis (DTA), thermogravimetric analysis (TGA), ther-
momechanical analysis (TMA), and dynamic mechanical analysis (DMA). Each of these will be discussed,
with examples of the information derivable from each procedure.

William S. Gilman

Gilman & Associates

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