High Throughput (HT) technologies are getting more and more interest of the coating industry to speed up coating development. With the High Throughput systems, you can automatically prepare coating formulations or perform synthesis like polymerizations, in parallel, and on small scale.
An HT system can be best described as a small lab, with reactors and raw materials all present in one cabinet. Typically HT is used to perform synthesis, mainly in the pharmaceutical industry, as these syntheses can take a long time and requires different handling at different stages. Other uses of HT nowadays are for:
− Catalyst research
− Polymer synthesis and formulation preparation, and
− Testing
So, let’s understand how an HT system can help develop science-based coating formulations with improved performance properties.
But before that, let’s introduce ourselves to the general coating development process…
Coating Development
Developing new coatings is not as simple as it looks. Once the right choice and balance of raw materials have been found, a coating formulation looks simple, but to achieve this, it takes a lot of effort. Finding the right raw material for a certain property is already a complex study and requires knowledge, experience, and understanding of the chemistry. For a certain raw material or property of your formulation are, in most cases, several materials of different suppliers or technologies available.
A coating does not exist of just one raw material, but of several raw materials that can influence each other positively or negatively. This all makes the development of a new coating a complex study that requires a lot of experiments to find the best properties. The same counts for modifying a coating. Changing or adding a raw material, to achieve a certain property, can also lead to several negative effects. Once again, reformulating of the coating takes time and requires various formulations to find the best solution. A coating is always a compromise, so therefore it is not easy to find an optimum.
Once the raw materials are selected, the process of grinding those together to achieve the coating with the right properties can be started. In most cases, the first shots are not as one would expect. A variety of unexpected properties can appear which do not fit with your original ideas before you started or which do not fit with your desired outcome. The process of reformulating by trial and error is then started, which can lead to even more surprising effects. A deeper understanding and searches for other raw materials can, in parallel, be performed in order to overcome the current problems. Finally, the right coating with the right balance of properties is then found and is ready for introduction.
This manual preparation of a coating on lab scale is typically performed by the use of a dissolver. In general, the resin is weighted into the can and stirred by the dissolver. The additives and solvents are mixed in whilst slow stirring. Then the pigments, fillers and functional pigments are added while mixing. This milling base is then stirred at high speed to obtain the required:
− Fineness
− Stabilization
− Activation
− Maximum color strength, and
− Temperature control
The temperature increase during the milling phase can be controlled by adjusting the stirring speed, by external cooling or by adding diluents to the milling base. A slower stirring speed will result in a decrease in temperature but will be less effective to achieve the desired fineness. When the milling base is finished, the rest of the binder, solvents, and additives are added during the letdown phase.
» Continue reading to understand how to develop coatings using HT system for improved results and reduced time