Continually evolving demands for greater coating performance and functionality, the increasing complexity of the regulatory landscape, and growing competition around the globe are driving the need for accelerated development of coating raw materials and formulated products and more rapid problem-solving capabilities. High throughput technology, originally developed in the pharmaceutical industry, is being adapted by companies in the coatings sector to meet these important and growing challenges.
Coating formulations contain many different ingredients―resins, additives, pigments, fillers, catalysts, solvents, co-solvents, water, etc. Exploring all the possible combinations for a given formulation is therefore impossible. On the benchtop in particular, the number of options that can be explored is quite limited. “For instance, if just 10 resins, 10 additives, 10 pigments, and 10 catalysts were to be considered for a formulation, 10,000 combinations are possible without considering different quantities for each,” says Claudia Bramlage, senior manager R&D Additives, Evonik Resource Efficiency GmbH. “To find the best formulation, it is important to explore a large number of these combinations. High throughput technology makes it possible to explore more of these options,” she observes.
Dow Chemical has invested heavily in high throughput technology for coatings for approximately 10 years, according to Sharon Kraus, TS&D director for Dow Coating Materials North America. “High throughput technology is not only a capability, but also a mindset and methodology that drives customer value generation,” she says. In coatings, one of the challenges to applying high throughput technology is the wide range of test methods used, including those that are required by regulations and others that are specific to different customers and third-party testing labs. “With such a rich menu of application tests, it is necessary to select the bench methods to develop as high throughput alternatives, and those must then be calibrated to the corresponding bench method and their equivalent performance validated,” Kraus explains.
The high-level strategy at Dow includes the development of formulation and application tools for producing and applying paint at a very small scale and performance tests that provide the same data as standard bench methods. Data management and analysis is another crucial aspect of the company’s high throughput efforts, according to Kevin Henderson, TS&D scientist for Dow Coating Materials North America. Projects range from polymerization/resin synthesis to formulating end products and everything in between.
Evonik has developed a high throughput system that automatically doses raw materials, formulating them into coatings, applies the coatings to substrates, and then tests them once they are cured. The system comprises 52 elements that combine to give 32 functionalities, each of which represents a specific task. The elements are connected within a track system by which containers and substrate panels are moved. The actions are performed by 13 robots. “On average, we can formulate 120 samples within 24 hours, and while they are being applied, cured and analyzed, a new set of experiments can be started,” says Ellen Reuter, director Innovation Management Additives, Evonik Resource Efficiency GmbH.
Some of the challenges Evonik has faced in setting up its high throughput system have included the dosing of viscous or reactive liquid raw materials and powder handling; pigment grinding; and coating application. The automated dosing system in combination with the RaceLab software developed by the company accounts for numerous parameters when dosing, resulting in reliable and reproducible performance, according to Reuter. For pigment grinding, a special mixer is used to allow faster grinding, and a filter adapter was specifically developed for separation of the grinding beads. For coating application, a robot was designed to apply the same quantity of coating at the same thickness each time. Most functionalities were not available off the shelf when Evonik started its high throughput project―they were jointly developed in very close collaboration with the chosen suppliers, enabling the Evonik team to gain a lot of handling expertise even before the equipment was installed in Essen, according to Bramlage.
Dow Chemical’s Core R&D group has established a broad range of high throughput capabilities, with some tools purchased off the shelf, but more than half designed in-house to meet the specific needs of Dow Coating Materials and its customers, according to Joe Manna, associate director of Formulation Science in Dow’s Core R&D group. The company benefits from its ability to do customized robotics and build very specific test methods for any given project. “With high throughput technology, we are identifying new approaches to innovation development and finding ways to drive innovation for Dow’s businesses and also help customers solve problems,” Manna observes. That includes refining workflows to investigate additive, resin, pigment, and formulated coating performance more quickly or from a different perspective than what is possible on the benchtop.
High throughput technology is helping Dow Coating Materials increase the efficiency and speed of product, formulation, and solution development as competitive pressures in the marketplace are requiring customers to reformulate their paint and coating products, according to Kraus. During the last decade, high throughput tools themselves have advanced, leading to even greater sample output. “Once calibrated and validated, high throughput methods can be used in design of experiment (DOE) approaches that explore much larger design spaces than is possible using conventional laboratory methods,” Kraus notes. That means both Dow Coating Materials and its customers can investigate many more options (150 vs 50 per week on the benchtop) and have a greater likelihood of developing optimal products or finding the most effective solutions. “With high throughput technology, we are able to reduce the time for new product development, have more efficient synthesis capabilities, and expedite the screening of experimental probes―which allows us to hone in on the most productive polymer compositions, raw material compositions, best formulation solutions, etc. In essence, we have gained the power to do more in a shorter period of time, including giving our customers more possible solutions,” she adds. As importantly, high throughput capabilities make it possible to explore ingredient interactions that cannot be investigated on the benchtop, which can lead to unique discoveries that bring new performance benefits, according to Manna.
Dow Coating Materials uses its high throughput capability for raw material consolidation projects with customers; to benchmark other paints, zeroing in on performance traits that meet unmet market needs or for customer-specific projects; to solve formulation issues; in new product development; and for research to explore fundamental properties and performance phenomena. For instance, the development of a high throughput hiding test to measure the scattering coefficient of paints was used within a larger high throughput workflow to determine how overall formulations impact hiding performance. Models were established using the generated data, and the results led to the development of Dow Coating Material’s EVOQUE™ pre-composite hiding technology.1 The company’s new ACRYSOL™ RM-725 rheology modifier was developed using high throughput technology, which made it possible to screen a large number of experiment probes to identify the molecule with the desired combination of target properties. Dow Coating Materials also uses its high throughput capabilities to explore polymer blends, for instance to simultaneously optimize cost and paint performance. More recently, high throughput imaging capabilities using optical analytics have been developed to evaluate defoamer performance and film quality more quantitatively than could be achieved previously.
“We take a modular approach to high throughput technology. This approach gives us the flexibility to use only those tools that are needed for a given project depending on the problem that needs to be solved and allows us to focus on the points that are crucial for our business partners,” Manna says.
Evonik’s high throughput system, according to Bramlage, provides more reproducible results than conventional benchtop methods due to automation of many tasks that can be subjected to manifold parameter influences. As mentioned, coatings are applied uniformly using a robot. Subjective test methods, such as the storage stability of pigment concentrates and the rub-out test for pigment stabilization, are also more objectively performed due to the ability to employ precisely coordinated control systems within the high throughput system. “Overall, the system also completes labor-intensive tasks, freeing laboratory staff to focus on experimental design and analysis. Our coating experts can now use their time to do challenging experiments instead of repetitive tasks,” notes Reuter.
Using the RaceLab software, it is possible to define as many as 40 different steps in Evonik’s high throughput system, using up to 600 parameters. “The system is very flexible; as a result, we can combine individual steps into a workflow that satisfies a diverse range of customer requirements,” observes Bramlage. All of the data generated using the high throughput system are recorded in the RaceLab software for analysis and data mining. “Using all these new learnings, we will become an even more valuable innovative partner for our customers,” says Stefan Silber, head of Innovation Management for Evonik’s Coating Additive Business Line.
Dow has also focused on developing advanced data management, analysis, and visualization capabilities. Using high throughput technology often results in the generation of large quantities of data. It is difficult, according to Henderson, to “see” the important results when there are thousands of data points. Prediction profilers constructed using historical data can be used in combination with 3D data visualization tools to depict the important results, helping both internal scientists and customers see all of the possibilities, according to Kraus. “The ability to predict performance before formulation reduces the number of formulations that need to be physically tested, which further speeds development,” Henderson adds.
“The possibilities for high throughput technology in the coatings industry are endless and only limited by individual creativity in terms of the ability of scientists to imagine how these tools can be used,” Kraus asserts. It is necessary though, she notes, to be mindful to properly adapt classic application science methods to high throughput methods. “It isn’t possible to develop high throughput alternatives for every conventional test method, but we are realizing that if we take the right approach, we can do more all the time,” she adds. High throughput technology also does not eliminate the need for great scientists, according to Manna. “It is a set of tools that helps world-class, innovative scientists in the discovery and development of next-generation coatings and coatings technologies,” he comments.
Dow continues to make modifications to its high throughput tool set, designing tools to bring more analytical capabilities. “It is not an invest-once-and-done field,” states Manna. “We are continually reinvesting and always looking to achieve the next generation of tools.”
Reference
- Mecca, J.M., Zhang, Q., Fasano, D.M., Cummins, D.A., and Hook, J.A., “Hiding Optimization in Architectural Coatings Using High Throughput Research,” paper presented at the 2012 Waterborne Symposium.