Measurement & Testing of Coatings 2009
12 - 13 May 2009, Birmingham UK
SESSION 1: Chemical Analysis of Coatings
1. An Overview of Measurement and Testing for Sustainable Innovation in the Field of Coatings Technology
Peter Collins
PRA, UK
This paper gives an overview of measurement and testing, emphasising the fundamental importance of reliable measurement and testing and providing a brief history of the subject. It examines uncertainty in measurements and how they should be dealt with. The nature and purpose of tests are considered, before moving on to discuss performance standards including the MPI approval process. The key issue of sustainability is examined including the crucial roles of life-cycle analysis and service life prediction in assessing the sustainability of coatings. Finally some of the key challenges facing the coatings industry in the field of measurement and testing are highlighted.
2. Accelerated Coating Research via High Throughput Experimentation
Pieter Castelein*, J. Paul, F. Horzenberger, S. Van Gils & G. Desie
Flamac (Flanders Materials Centre), Belgium
Combinatorial and high throughput (HT) material research is a relatively new methodology that has proven to be a valuable tool for the development of new materials. Besides HT coating application, several screening techniques are available at the Flamac (Flanders Materials Centre). Analysis of ultra-thin coatings on metallic substrates is possible by use FT-IR equipped with grazing angle objects. Color and optical appearance is also screened in a automated way. Nanoindentation is available to measure the hardness, the Young's modulus and the yield point while scratch tests could lead to the friction coefficient. Layer thickness and structural analysis of organic as well as hybrid coatings could be performed by GDOES. All tools are linked to a central database using barcode tracking.
3. XPS - A Tool for the Chemical Characterisation of Coatings and Interfaces
John Wolstenholme
Thermo Fisher Scientific, UK
X-ray photoelectron spectroscopy (XPS) is widely accepted for the quantitative, chemical characterisation of surfaces, thin films and interfaces and is commonly used for both failure analysis and development of new coating systems. The performance of coatings is, in part, determined by the chemistry of the surfaces and interfaces involved. XPS allows the analyst to obtain chemical state information only from the top surface or interface region of the specimen.
This paper will include a description of the technique and the required instrumentation. It will go on to provide several relevant examples of its application to the coatings industry. Examples will be given in the area of coated glass and painted surfaces showing, in detail, the information available from this powerful technique.
4. Surface Analysis Techniques for Coating Characterisation
Justine Bentley
Ceram Surface and Materials Analysis, UK
The interaction at the interface between one material and another (eg coating and substrate) is critical to the performance of the product in operation. Thus knowledge of the chemistry & the physical characteristics of the interfaces is essential and helps to understand the nature and functionality of material interfacial interactions in terms of their composition and shape. This is particularly useful in both the initial development of coating materials and in failure investigations (eg disbondment, pinholing, corrosion). Chemical mapping of materials can tell what is present, where it is and how much is there - for all the elements and for molecular fragments as large as 10000 mass units, with high sensitivity.
In this presentation four primary techniques used for the analysis of the surface of materials will be described with reference to the determination of both their chemical and physical character. These are, X-ray Photoelectron Spectroscopy (XPS) Time of Flight Secondary Ion Mass Spectrometry (ToFSIMS) Dynamic Secondary Ion Mass Spectrometry (DSIMS) and non-contact 3D Profilometry using white light interferometry (3DP). The first three of these techniques, in combination, can provide highly sensitive (ppm) quantitative information on the elemental, molecular and oxidation state composition of surfaces and sub-surfaces, which may be presented as spectra, chemical maps and depth profiles. 3DP generates three-dimensional images of the surface with nanometre resolution on the vertical axis and a quantitative statistical measure of area surface roughness. It can also be used to measure coating thickness. In many cases it is possible to overlay the chemical information onto the physical profile.
Examples of the application of these techniques to commercially relevant industrial coating materials will be described.
SESSION 2: Liquid Coating Characterisation
5. Viscosity - Shear Facts
Alistair Kerrigan/Derek Gerk
Sheen Instruments, UK
An analysis of the importance of viscosity in modern day paint manufacturing , where duplication of parameters including Viscosity is so important to the reproducibility and overall quality of the finish. This all starts with rigorous within the material manufacturing process in particular Viscosity.
We take a look at several aspects to Viscosity including:
Basics - How it is used , what methods are available and why we use the option we do.
Practical - How we interpret results and how close control of the viscosity process can actually allow for a more cost effective manufacturing process.
In Depth - The structure of the materials and what information we wish to derive from our tests , Shear sensitivity ( thickening + thinning ) , Development.
Experiences - Viscosity in practice with some case studies.
6. Rheological Measurements for the Coating Industry
Steve Goodyer
Anton Paar, UK
A brief introduction to rheology and some typical tests performed in the coatings industry. The relevance of each test to coatings performance/formulation is discussed along with an explanation of some typical results.
7. Understanding the Links Between Rheology and Particle Parameters
Dr Adrian Hill
Malvern Instruments, UK
The rheology of a suspension is influenced by particle size, particle size distribution, and the volume fraction of solids present. Zeta potential, a measure of the electrostatic interaction between particles in the system, also has a marked effect. In this talk, the relationships between rheology, particle size parameters and zeta potential are discussed. The information provided is intended to give people sufficient understanding to successfully manipulate variables in order to produce materials with the required viscosity.
8. Zeta Potential Measurement for Probing the Adsorption Behavior of Wetting and Dispersing Agents on Pigments
Dr. Thomas Veit*, Claudia Bramlage & Ellen Reuter
Evonik Tego Chemie, Germany
Effective and reliable long-term stabilization of pigments in coatings is essential for the coatings industry. This especially holds true for aqueous coating systems. To address this challenge a multitude of wetting and dispersing additives coming from many different chemical classes are utilized today. However, approval of these additives as wetting and dispersing agents for different pigments in several formulations is time consuming. Therefore, completion of application tests with investigations focusing on structure-property relationships appears to be helpful. Electroacoustic measuring methods seem to be a powerful tool to look into the adsorption behavior of wetting and dispersing agents on pigments in terms of surface coverage. Displacement experiments with binders for example gain access to interactions with wetting and dispersing agents and their specific interactions with pigment surfaces.
SESSION 3: Dry Film & Mechanical Properties
9. Optical Film Formation Analysis
James Holloway*1, Hélène Dihang2 and Laurent Brunel2
1Fullbrook Systems, 2Formulaction, France
An optical technique based on Multi Speckle Diffusing Wave Spectroscopy (MS-DWS) has recently been developed to study the film formation of coatings. The kinetics obtained allow direct comparison of various coatings, on any kind of substrate, and the possibility to access characteristic times (open time, touch-dry). For latexes, and most waterborne systems, the kinetics of film formation display a peculiar curve in four stages, corresponding to the four stages detailed in the literature for latex (i.e. evaporation, packing, particle deformation and interdiffusion). This same technique can also be used to study rheological properties of the film (viscous and elastic modules) while it is forming. This gives access to the visco-elastic properties without any mechanical stress during the film formation.
10. A Study of the Effect of Temperature on the Hardness of Coil Coatings
Alan Butchart* & Dr Chris Lowe
Becker Industrial Coatings, UK
An overview of the effect of temperature on the hardness parameters of coil coatings, with comparisons to glass transition temperatures.
11. In-situ Microtribology with High Local Resolution on SiOx Coated PE
Dr. Wolfgang P. Weinhold*, Ralph Stengler & Thomas Schüßler
Innowep, Germany
Common material properties, e.g. hardness, tensile modulus and strength, poisson´s ratio, are well known. On the other hand, properties of thin layers can differ significantly from those data, in particular for micro-/nano-particle systems. AFM and FFM methods work with excellent lateral, topographic and force resolution but often do not provide testing situations close to practical applications.Optimization of scratch and wear properties need access to measurement techniques, that cover the gap between micro and nano scale. In-situ measurements of scratch resistance with stepwise increase of load correlated with simultaneous micro force measurements are of great relevance for the characterization and differentiation of materials.This new in-situ micro-structure procedure with high local resolution opens completely new doors in understanding of microtribological phenomena on all types of materials.
12. Investigation of Scratch and Mar Resistance of an Organic-inorganic Automotive Nano Clear Coat Using an AFM Coupled Nano-indentation Method and a Simulated Car Wash Test
M. Mohseni*, S.Vala & A. Karbasi
Amirkabir University of Technology, Iran
The base coat/clear coat automotive paint systems have been used increasingly in recent years because of their attractive appearance and due to the excellent gloss retention they impart compared with the conventional monocoat solid systems. However, coating failures may usually occur upon exposure to aggressive environment such as car washing, sun and other damaging sources. This work was an attempt to enhance the scratch resistance of a solvent-based clear coat through an in situ production of silica particles using a sol-gel processing as an alternative approach to incorporate nano silica into the coating. Tetraethyl orthosilicate(TEOS) and methacryloxy propyltrimethoxy silane (MEMO) were incorporated into the acrylic-melamine clear coat to obtain an in situ formed siloxane structure. The scratch behavior of the resulting coatings was investigated by Vickers hardness, AFM coupled nano-indentation as well as by a simulated car wash test. Samples showed different behavior in nano and macro scales. This was discussed based on the viscoelastic properties of the coatings and their ability to heal the scratched area after exposure to different indentor tips. The highest improvement in overall coating properties and the lowest gloss loss in the simulated car wash test were observed for the clear coat containing non-hydrolyzed TEOS and hydrolyzed MEMO.
13. The Best Accelerated Weathering Test for Coatings. Does it Exist?
Cees van Teylingen
Atlas Material Testing Technology BV, Netherlands
The improved durability of paint and coating systems results in outdoor weathering tests with very long durations. The time to market for new coating systems is predominated by the time required for the results of the weathering test(s). The need of accelerated weathering tests is obvious. This paper explains some of the methods used to reduce the time needed to generate reliable weathering results. Acceleration of outdoor weathering tests with natural sunlight as well as the use of laboratory equipment including the different test methods and test cycles will be explained in detail.Correlation between natural weathering testing and laboratory testing is a critical aspect of reducing test durations, this aspect is also discussed in this paper.
14. Cyclic Corrosion /Weathering Testing: Validating a Test Cyclic With A Decade of Research.
Jim Regan2*, Patrick Brennan1, Danica Zeise1 & James Gauntner1
Q-Lab Corporation, USA1, Q-labs, UK2
Cyclic corrosion testing is widely recognized as providing the best possible laboratory simulation of natural corrosion. Many different cyclic corrosion tests have been developed. Simple cycles, such as Prohesion, may consist of cycling between salt fog and dry conditions. More sophisticated methods may call for multi-step cycles that incorporate humidity, condensation or other conditions, in addition to salt spray and dry-off.
One specific type of cyclic test, a corrosion/weathering method, was developed in the 1980s by researchers at the Sherwin Williams Company to test industrial maintenance coatings. The test was based on the theory that as these coatings degrade from UV exposure and their ability to protect against corrosion is reduced. In addition, by introducing the Prohesion electrolyte, the products of corrosion would be more similar to those specimens exposed to a real world industrial environment.
By combining the Prohesion testing with accelerated QUV weathering testing, the gross corrosion rates and morphology of the products of corrosion were found to be more like outdoor results. This new weathering/corrosion cycle was standardized in ISO 19977-2 and ASTM D5894.
More than a decade later, research from leading paint companies validates the usefulness of weathering/corrosion testing for R&D, QC and correlation studies. This is because results obtained from both lab and long-term field exposures exhibit the same types of degradation and modes of failure. This paper reviews the weathering/corrosion tests results of different industrial maintenance coating systems including lower VOC coatings such as waterborne acrylic coatings and silicone based coatings. Additionally, some of the industries leading experts from Rohm & Hass, International Paints, Q-Lab Weathering Research Service and Sherwin Williams provide their insights about weathering/corrosion testing as well as recommendations for modified cycles developed for special applications.
SESSION 4: Visual Properties of Coatings
15. New and Innovative Testing Technologies for Effect Finishes
Sandra Weixel
BYK-Gardner, Germany
The look of effect finishes is continuously changing to create distinct visual appearances. Therefore, the range of effect pigments - different aluminum grades to special pearlescent pigments - used in automotive and industrial applications is increasing. Designers are searching for colors which can change their look depending on the lighting conditions to pronounce the styling of a product. These types of effect finishes can appear grayish under cloudy sky, but start to live with colorful sparkling effects in the sunshine. On the other hand color harmony with add-on parts, uniform application without causing undesirable effects such as "cloudiness or mottling" and easy as well as cost efficient repair (liquid metal) is becoming more and more of a challenge.
New and innovative testing technologies were developed to quantify special effects such as sparkle, graininess and mottling with image analysis. The factors influencing the total color impression will be discussed and explained using examples from the automotive industry.
16. Major Advances in the Reliable Measurement of the Colour and Appearance of Special Effect Paints and Coatings
Rafiq Mulla* & Jon Nisper
X-Rite Incorporated, USA
Instrument manufacturers have developed an accurate and reliable method to precisely measure the visual properties of colour and gloss of special effect coatings that have confounded prior generations of optical instruments. Corporations now have the tools necessary to institute robust quality control for products such as automotive body panels and appliances parts that are coated with special effect paints. Engineers have created a three-dimensional mathematical model for colour and appearance that can be used to distinguish any special effect coating. The method detects and quantifies the Z-axis of colour space by adding more sensors and illuminators to a spectrophotometer to gather information from a third axis of light emanating from the test surface.
17. New Approach to Evaluate the Weathering Effects on Exterior Wood Coatings
Dr Davide Menotti
University of Udine, Italy
