Coating formulation and production principles
Coating production has always been batch production in which the pigment dispersion takes place. However, new in-line dispersion and formulation principles make the production more effective.
In-line dispersion principles
Traditionally, coating production has always been batch production in which the pigment dispersion takes place. However, new in-line dispersion principles have recently been introduced making it possible to transform from batch to semi-continuous mode. The aim is to convert to full-continuous mode in the future.
The dispersion of pigments into the coating binder phase is one of the most critical unit operations in coating production. When pigments are manufactured, the individual particles will be present in porous agglomerates due to physical interactions. During the subsequent coating production, these agglomerates need to be taken apart into smaller units to provide the right properties to the coating.
This dispersion process is complex and consists of three separate steps: wetting of pigments, breakage of agglomerates and stabilization of the primary particles. Depending on the type and purpose of the pigment, the dispersion techniques may vary.
The in-line mixers seem so far to be very efficient on many types of pigments; however, more research on the dispersion mechanisms is needed to be able to work on all types of pigment agglomerates. The in-line mixers also make it more feasible to benefit from paint production via intermediate products in modular manufacture.
Disciplines involved in efficient coating production are chemical process technology, chemical unit operations and chemical/physical analytical techniques.
- The coatings society needs new and more efficient production principles
- The aim of this research is to get a better understanding of pigment dispersion and transfer this knowledge to coating production
- The research is performed by combination of theoretical studies, mathematical modelling, dispersion analysis and coating production in modern in-line mixer
Projects
Objective
This project primarily focuses on the dispersion principles of coatings. The overall research involves investigating reliable on-line quality control methods of evaluating the particle size distribution and the rheology measurement. The current dispersion equipment will be reviewed, including the dispersion mechanism, and application areas. Furthermore, the advantages and disadvantages of different dispersion equipment will be analysed. Theoretical models to review the dispersion process of the high-speed disperser and other dispersion equipment will be developed.
Background
The new paradigm of in-line continuous or semi-continuous production equipment based on new dispersing principles has shown significant advantages compared with the current dispersing method. However, none of these new production methods are commonly performed in the coatings industry. Therefore, research needs to be done to review these instruments. A special design dispersion instrument for the coatings product can be developed to help to improve the manufacturing process. Besides, active and extensive on-line quality control instruments (e.g. rheology, particle size distribution, and colour) are also required.
The project
For the degree of the dispersion, laser diffraction and SEM were used to study the distribution properties. The rheology property of the coatings was measured by the capillary rheometer and advanced rheometer. The advantages and disadvantages of these methods were evaluated. After the full particle size distribution can be determined, the formulation of coating samples and the manufacturing process will be modified to determine the best distribution conditions. The relationship between the full particle size distribution, the formulation of coatings, and the manufacturing process will be evaluated. A mathematical model will then be developed to describe the dispersion process.
Funding
The Hempel Foundation and the Technical University of Denmark (DTU). The project runs from 1 September 2019 - 31 August 2022.
Supervisors
Søren Kiil (main supervisor)
Claus Erik Weinell (co-supervisor)
Kim Dam-Johansen (co-supervisor)
Contact
Shicong Luo Student Students s161492@student.dtu.dk
Contact
Søren Kiil Professor Department of Chemical and Biochemical Engineering Phone: +45 45252827 sk@kt.dtu.dk
The transition from solventborne coatings to waterborne coatings brought many advantages. But is there a way to make it even better—more cost-effective, sustainable, and regulation-free? This project focuses on eliminating the water content and exploiting the advantages it brings along the supply chain.
Waterborne paints and polymer dispersions are produced, transported, stored and sold in water as solvent. In fact, approximately half of the can is usually water. Because there is water in the container, biocides are also added to stop microbial growth. Therefore, eliminating the water content along the supply chain would provide great benefits including,
- Decreased transportation and storage costs,
- Removal of biocides (which is getting more strictly controlled by the regulations),
- Reduced waste,
- Label-free products.
The main aim of the project is to transform the polymer dispersions into powder form, the so-called Re-dispersible Polymer Powders, by utilizing well-known drying processes. Ideal powders should be capable of reforming the original dispersion when mixed with water, without sacrificing any of the original properties.
Funding
The Hempel Foundation. The project runs from 1 December 2021 - 30 November 2024.
Supervisors
- Kim Dam-Johansen
- Søren Kiil
- Narayanan Rajagopalan
Contact
Okan Aggez PhD student Department of Chemical and Biochemical Engineering okaag@kt.dtu.dk
Contact
Kim Dam-Johansen Professor, Head of Department Department of Chemical and Biochemical Engineering Phone: +45 45252845 KDJ@kt.dtu.dk