The Waterborne Symposium

Abstract
Coatings are complex composites designed to have a stable shelf-life, apply easily to a substrate, and provide lasting durability in varied environments. These performance criteria require disparate materials to be finely dispersed and work cohesively, which presents a major challenge as composites can be unstable and ultimately fail at points of inconsistency. To address this, the first thing a new paint chemist learns is that wetting agents are mandatory in allowing mineral fillers to disperse properly. Without them, these inorganic particles generally reject their organic media, agglomerate and settle out. It would be imprudent to forgo wetting agents.
Another well-known, tried-and-true technique to stabilize composites and improve their uniformity is to use high-quality, gel-grade attapulgite mineral products. They have been common in paint applications for several decades as thixotropic thickeners for low-shear flow and leveling, sag and spatter resistance and other rheology benefits. However, a seemingly forgotten higher value is their function as excellent stabilizers due to their unique colloidal lathe-shaped particles forming a stable lattice structure. This keeps liquids and particles more evenly dispersed and suspended, generating important benefits well beyond rheological properties; such as syneresis control, improved tint strength, hiding and freeze-thaw, and reduced color float and flooding.
This article gives a brief history of attapulgite, a description of its mechanism that sets it apart from other thixotropic thickeners and stabilizers, and discusses its performance benefits in coatings.

Scanning electron microscopy (SEM) and focused ion beam (FIB) techniques, together commonly known as a DualBeam, have long been a critical component for the analysis of polymer, ceramic, and metallic coatings.  Recent advances in ion beam technology have opened the practical application space to the processing and data collection from larger areas and greater volumes.  Due to throughput limitations, the common site-specific cross-sections were no larger than 50 - 100 µm; volumes for three-dimensional (3D) analysis measured in the tens of cubic microns.  The development and incorporation of the plasma focused ion beam (PFIB) has increased this by an order of magnitude, making up to 1 mm site-specific cross-sections a common feature.  Analytical volumes, including 3D imaging, 3D energy dispersive X-ray spectroscopy, and 3D electron backscatter diffraction, have also expanded significantly.  These greater areas and volumes have improved the analysis of large features and increased the statistical relevancy of DualBeam data, aiding decision-making based on information derived at the micro- and nanometer scales.  This paper will discuss the advances in PFIB technology and provide application examples of polymer, ceramic, and metallic coatings.

Coatings have a broad range of applications in industries like pharmaceuticals, automotive, medical devices, textiles, oil and gas, aerospace and defense, food and packaging, and consumer optics, thanks to their role as functional, high performance or protective materials.  To meet stricter environmental regulations, increase sustainability and meet new customer demands, improving the
design of coatings and optimizing their performance is of critical importance to further advance innovation while remaining competitive in price. In addition, it is also important not only to develop novel materials, but also to maintain and ensure the quality of coatings while reducing the commercialization cycle.
Researchers rely on characterization techniques that help them understand the relationships between structure, properties, performance and process of coatings. Characterization includes 2D analytical solutions, 3D non‐destructive imaging and in situ capabilities, as well as advanced software packages that equip researchers to become pioneers in this field and expand the portfolio of coatings to new markets.
Characterization (microscopy, modelling and simulation, image analysis and spectroscopy) is used to determine the chemical composition as well as mapping contaminants and defects that influence the performance of coatings. In addition, these tools help researchers understand the structure and morphology, adhesion failure, as well as how the process variables influence the material properties. From looking at cross sections, delamination, corrosion to extracting actionable information from micrographs (thickness measurement and particle size distribution) and obtaining texture and roughness information, microscopy solutions provide new insights. In addition, uniformity and coverage of coatings, the presence of pores, microstructure and texture, segmentation and analysis of different features of interest as well as topography investigations can be determined.
This paper illustrates a case study on how optical and confocal microscopy, focused ion beam and correlative microscopy is used by ZEISS Vision R&D to make sure that new customer demands are met while keeping the quality and great performance of coatings.

After working in coating labs for over 45 years, I have seen a lot of changes. This presentation will highlight some of the changes (government regulations, raw materials, etc) and the reasons for them. In some cases, the changes caused more problems than they helped. One example is OSHA. Protecting employees was needed. But some of the original regulations would come as a surprise to most people who were not around then. The same can also be said of the original air pollution regulations.
In a fun way, I will explain some of the things that I have learned (and wished I had learned sooner) over the past four and a half decades.

Steve Raper
Chemquest Technology Institute
100 Confroy Dr
South Boston, Va 24592
sraper@chemquest.com

Of late, there has been increased interest in waterborne acrylic elastomeric roof coatings. because they reduce the heat absorption of buildings compared to traditional asphalt roofs.  In addition to heat prevention and energy savings, acrylic roof coating protects the underlying material from water, ultraviolet (UV) radiation, chemicals, and wear.
Waterborne acrylic roof coatings are traditionally thickened with cellulosics such as hydroxyethyl cellulose (HEC) and associative thickeners such as hydrophobically modified ethoxylated urethanes (HEUR) and hydrophobically modified alkali swellable emulsions (HASE).  The use of these thickeners often leads to challenges with both water resistance and water absorption of the coating.  Additionally, the control of syneresis and sagging is often challenging.
Microfibrillated cellulose (MFC), a biobased and multifunctional product made of cellulose is a new alternative to traditional thickeners. MFC consists of fibrils with lateral dimensions in the nanoscale and lengths up to micron scale.  These strong and rather stiff fibrils form strong films (tensile strength up to 210 MPa).  Once MFC is added to a paint, it is usual to see a noticeable effect on the mechanical properties of the final coating.  In addition to the effect on mechanical properties, its unique rheological properties allow for increased stability as well as an easy to apply paint.  The high yield stress of MFC prevents settling of heavy particles as well as floating of hollow microspheres, whereas the strong shear thinning allows the spraying of thick formulations.  This exceptionally thixotropic behavior leads to excellent sag resistance combined with good leveling.
The aim of this work was to evaluate the effect of MFC on the key properties of acrylic elastomeric roof coatings, such as tensile strength, water resistance, mudcracking, and adhesion to metal and concrete surfaces. Commonly used thickeners (HEC and HEUR) were used as references.  Different fibrillation degrees and dosage levels of MFC were used to clarify the impact of MFC on tensile strength and elongation as well as the relationship between these two parameters.
We will demonstrate how MFC increases the tensile strength of elastomeric acrylic roof coating without sacrificing the elongation and performance of the coating.

The use of Design of Experiment (DOE) methodologies in the industrial setting has gained a lot of interest in recent years and is being used more frequently.  There are several types of designs that can be used to decrease variation, improve quality and reduce costs, e.g., Taguchi Robust Product Design, Response Surface Methods, etc.  Typically, DOE is limited in industrial manufacturing to designs with less than 16 runs.  The results from these studies do not always account for long-term variation that occurs at the full-scale production level given the differences in process variation, raw materials, etc. over time.  One technique that attempts to account for long-term variation using the results of designed experimentation results is Evolutionary Operation (EVOP).  EVOP was first proposed by Box (1957).  The application of this technique in the wood products industries will be discussed with benefits and shortcomings highlighted.

Tribology capabilities on commercial rheometers have enabled measurements at lower load forces, friction forces and sliding speeds than industrial tribometers.  These “soft tribology” measurements have proven useful in predicting sensory properties such as mouthfeel or texture.  As tribology is a measurement of surface interactions, the results are highly dependent on test fixture material.  To detect differences perceived by human touch, it is beneficial to select materials that mimic the surface properties of our skin.  Sensory perception is also a consideration for high-contact solid surfaces like personal electronics, or coatings for surfaces in the home, such as matte or gloss paints. Tribology can evaluate the “feel” of these solid surfaces, with appropriate fixtures.  The measurements presented compare steel fixtures with surfaces modified to better mimic skin properties.  An optimum surface material will provide differentiation between samples and minimize variability between measurements.

Abstract 
The specialty chemicals industry is a great example of a legacy market that is ripe for a digital awakening. While we are still at the dawn of digital in coatings, organizations that are driving business decisions based on data are already seeing signs of success and leadership.
In this session we will provide a framework that will help you:

• Assess where you are on the digital adoption curve
• Get checklists for gap analysis, project prioritization and vendor selection
• Connect digital initiatives to operating benefits.

We will then apply the framework to two use cases: 1) cost efficient formulation and 2) enabling growth through M&A.

As a follow-up study to a previously reported increase in film flexibility, the film formation at temperatures from 45 to 115°F of films of an asphalt emulsion based driveway sealer with and without the post-addition of fibrillated high-density polyethylene fiber has been investigated. Utilizing six different grades of synthetic fiber, the nominal diameter and the nominal length of the fiber varied from 5 to 15 microns and from 100 to 900 microns, respectively. The resulting propensity of film formation has been shown to generally increase with fiber size; small fiber promoting less film formation than medium or large fiber. In addition, the resulting film formation has been shown to generally increase with fiber application rate; an increasing film forming trend from 0.5% to 1% to 2% fiber. Furthermore, a strong correlation between film formation and the ultimate elongation of the film has been observed.