Driers are agents that expedite the curing, i.e., drying, of coatings and printing inks after application. While cobalt driers have traditionally been the most commonly used, cobalt compounds have come under greater scrutiny as being potentially carcinogenic or otherwise toxic to humans and the environment. In addition, the fact that cobalt mining is limited to only a very few countries makes price fluctuations another concern. Accordingly, demand for cobalt-free alternatives has continued to increase, notably in the European Union (EU). Seeking to help resolve this issue, DIC has developed a new cobalt-free drier* that complies with EU environmental regulations.
For this article, we spoke to three DIC employees involved in research and product development in the area of cobalt-free driers who played a key role in the realization of this innovative product.
(From left) Takamitsu Kuriyama, Functional Additives Sales Group, Performance Material Products Division; Manager Hiroaki Nakano, Processing Technical Group 3, Processing Technical Division; and Assistant Manager Ryo Yamamoto, Functional Additives Sales Group, Performance Material Products Division
As anyone who has ever painted a wall or a piece of furniture likely knows, while the surface of paint dries quite quickly, complete drying through to the paint’s interior can take quite a bit longer. The reason for this is that it takes time for chemical bonds to form between the resin molecules in the paint.
DIC manufactures a variety of driers, which are agents that expedite the curing, i.e., drying, of coatings and printing inks. These are mixed into the Company’s own coatings and inks, as well as being sold as standalone additives to other manufacturers of coatings and printing inks around the world. The Company’s lineup ranges from products that deliver particularly excellent surface curing to those that ensure superb interior curing. DIC is particularly well known for its DICNATE series of high-performance driers, which boast a variety of outstanding properties.
The raw material for most driers is cobalt, which possesses a powerful catalytic effect. As of 2019, approximately 71% of the world’s production and 51% of its reserves of this rare metal*sup> were in the Democratic Republic of Congo (DRC), in central Africa. Because of political instability in the DRC, procurement risk is a major issue. Concerns about a tight supply–demand situation have also intensified in recent years, owing to a sharp increase in demand for cobalt as a cathode material for lithium-ion batteries (LiBs) used to power electric vehicles, which are seen as vital to global decarbonization efforts.
Manager Hiroaki Nakano of the Processing Technical Division’s Processing Technical Group 3, describes conditions in the global cobalt market as follows:
“Given the significant growth in demand in recent years, the price of cobalt is expected to rise in the future. There are also concerns that some cobalt compounds are carcinogenic or otherwise toxic to people and the environment. As a result, demand for cobalt-free alternatives has continued to accelerate across the EU chemicals industry. DIC recognized a unique business opportunity for it to develop highly safe cobalt-free driers that would help address these issues, as well as contribute to a more sustainable society.”
Coatings and inks are an important part of daily life. Driers are crucial to the achievement of high-quality coated and printed surfaces.
A key factor spurring demand for cobalt-free driers in the EU was the tightening of regulations set forth in its Registration, Evaluation, Authorisation and Restriction of Chemicals (REACH) legislation, which originally came into effect in June 2007. As a result, companies bringing chemical substances into the EU in quantities of one tonne or more are now required to register those chemicals with the European Chemicals Agency (ECHA), while the use of substances that are potentially harmful may be prohibited or restricted. Eighteen months later, in January 2009, the Classification, Labelling and Packaging (CLP) Regulation came into effect, making it obligatory for all chemical substances to be labeled with the appropriate pictograms from the Globally Harmonized System of Classification and Labelling of Chemicals (GHS),* designed by the United Nations (UN) to communicate the hazard class of chemical substances in a clear, easily identifiable manner.
The enactment of REACH and the CLP Regulation, which join the Restriction of Hazardous Substances (RoHS) Directive, adopted in 2003, underscore a rising awareness on the part of EU manufacturers of the impact of chemical substances on human health and the environment.
GHS pictograms appearing on DICNATE cobalt-free drier labels. DICNATE cobalt-free drier labels require either one or two GHS pictograms.
Many countries and territories around the world have passed similar laws and regulations. The United States, for example, has the Toxic Substances Control Act (TSCA), while Japan has the Act on the Evaluation of Chemical Substances and Regulation of Their Manufacture, etc. However, with a few exceptions—notably the EU and the Republic of Korea—registration is only required for new chemical substances, while laws and regulations governing existing chemical substances are generally not as strict as in the EU.
REACH requires the registration of all chemical substances, both existing and new, emphasizing the rigorous nature of regulations governing the use of chemical substances in the EU. In addition, since January 2021, the United Kingdom, no longer a member of the EU, has established its own new REACH-based regulatory framework for chemical substances called UK REACH.
“In response to these and other steps to tighten regulations governing chemical substances, EU-based chemicals manufacturers have stepped up R&D aimed at proposing cobalt-free alternatives in a variety of areas, including driers,” says Assistant Manager Ryo Yamamoto of the Performance Material Products Division’s Functional Additives Sales Group, outlining the circumstances that led to DIC’s decision to take on this challenge. “In 2010, DIC also resolved to begin developing cobalt-free driers.”
“I had more than a few eye-opening experiences with the EU’s strict regulations, which are quite different from Japan’s,” says Ryo Yamamoto, assistant manager of the group responsible for sales of additives.
DIC initially selected several candidates that offered promise as a replacement for cobalt and embarked on efforts to design a new product. However, the incessant implementation of new and increasingly stringent regulations added to the difficulty of this task, forcing the Company back to the drawing board again and again.
“I went to Europe multiple times to meet with relevant people at many different paint and printing ink manufacturers,” shares Yamamoto. “Without fail, they were acutely conscious of safety and environmental concerns. Even when I succeeded in attracting their attention by introducing our newly developed cobalt-free drier and providing them with samples, if there was anything else they found even slightly concerning they completely unable to even consider dealing with us.”
Hiroaki Nakano was appointed manager in charge of the development of cobalt-free driers in 2020. Prompted by DIC’s experience with EU manufacturers, he amended the development policy to prioritize safety and to revamp the product design from the ground up. At the same time, he recognized that giving precedence to safety would make it difficult to attain a correspondingly high level of performance, so he saw resolving this particular conundrum as his biggest task.
“We chose manganese, the health hazards of which are minimal, as the base material for our new drier. Accordingly, the challenge facing us was finding a way to improve manganese’s curing performance, which is inherently inferior to that of cobalt,” Nakano explains. “Basic technologies for improving the performance of this particular base material in other applications already existed, so we leveraged those and conducted repeated tests to determine the optimal combination of manganese and additives to improve the drier’s functions and achieve the desired performance.”
Manganese is a silvery-white metal
For testing to evaluate curing performance, DIC used a drying time recorder that can measure the curing time of different coating formulations in a maximum of 10 separate lanes simultaneously. Layers of coating or ink containing driers made with diverse raw materials in different volumes are applied to individual glass plates at a uniform thickness and a needle is dragged across the coating as it cures. Curing time is measured by examining changes in the imprint of the needle on the coating/ink surface.
“I felt it was important that I mixed the materials for testing and that I evaluated the curing times myself,” says Nakano. “This enabled me to get a better feel for the impact of formulations with different base materials on curing performance and tonality. I believed this would also position me well to advise coatings and inks manufacturers from a frontline perspective going forward.”
After a year of testing, DIC succeeded in developing a manganese-based drier that boasted a curing performance for both coatings and inks that was equal to or better than conventional cobalt-based driers. This was also the moment the Company attained its goal of perfecting a cobalt-free drier that delivered both a level of safety and a curing performance acceptable even in the EU.
Drying time recorder
At the time of application, the coating/ink is wet, so it is not permanently ruptured by the needle. Viscosity increases as the coating/ink begins to cure. When the coating/ink is completely cured, no imprint is left by the needle.
With plans to present its new cobalt-free driers directly to manufacturers in the EU put on hold because of COVID-19, in April 2021 DIC issued a press release, posted on its global website, announcing the development of DICNATE ESG-130BZ, for use with alkyd coatings, and DICNATE MV130A, for use with coatings and printing inks. Concurrently, DIC began shipping samples to EU coatings and inks manufacturers in collaboration with DIC Group wholly owned subsidiary Sun Chemical Corporation, based in the United States.
Responses have been positive and DIC has received inquiries from several companies to which samples were shipped. Of the two products in the series, DICNATE MV130A—which uses sustainable plant-based esters as solvents that are far less harmful to health and the environment than are conventional hydrocarbon solvents—has earned particularly high marks.
“We are just one step away from launch,” enthuses Ryo Yamamoto. “We have scaled up from lab-level to close to commercial production and are currently preparing to provide new samples produced at that level. We are ready to begin shipping commercial products as soon as we get the go-ahead.”
“DIC recently exhibited at the Kansai Sustainable Material Expo, held in Osaka,” notes Takamitsu Kuriyama of the Performance Material Products Division’s Functional Additives Sales Group. “While visitors showed a high degree of interest in recyclable products such as biomass-based resins, curiosity regarding cobalt-free products was still low. I think that is representative of the situation across Japan. In contrast, the shift to cobalt alternatives in the European chemicals industry is clear, as a result of which many competitors are racing to develop new technologies involving cobalt alternatives,” he explains, referring to recent moves by companies around the world looking to enter the EU market.
“Like DIC, most of these companies begin with a manganese-based drier and then devise additives to improve curing performance, but there are companies looking to beat EU regulations by using entirely new materials or by polymerizing cobalt. DIC will continue working to improve the performance of its cobalt-free driers with the purpose of fortifying its ability to triumph over its competitors.”
“From a global perspective, the development of environment-friendly products is an essential challenge,” says Takamitsu Kuriyama, whose responsibilities center on sales of functional additives.
Given the potential of cobalt-free driers to contribute to safety and environmental protection, DIC’s development of DICNATE ESG-130BZ and DICNATE MV130A is highly relevant to the Sustainable Development Goals (SDGs), adopted at the UN Sustainable Development Summit in 2015, the achievement of which is essential to sustainable development for the planet.
“In addition to working at DIC, I lecture part-time at a university,” explains Hiroaki Nakano. “In recent lectures, I talked about DIC's approach to developing cobalt-free driers. Students tend to be very conscious of social issues and the SDGs, so I was pleased to receive comments like ‘I’ve gained a new appreciation of DIC as a company that develops advanced technologies,’ and ‘I too would like to help develop technologies that contribute to safety and environmental protection in the future.’”
“I also showed my students photographs of us testing the curing performance of DIC’s new drier,” Nakano continues. “Some of them expressed their delight at seeing an actual laboratory, given that lab experiments had been impossible for so long due to COVID-19.”
After DIC’s April 2021 press release, Nakano received an email out of the blue from an executive in the development division of a major U.S-based global IT company, who praised DIC’s efforts to eliminate the use of cobalt. “I had never met this person, so I was very surprised to get such an email,” he remarks. “For DIC to receive such a compliment for its commitment to helping ensure a sustainable society is a great honor. It is also a powerful motivator for us in our future development efforts.”
“I’m scheduled to be a speaker at the conference of the European Coatings Show, a leading coatings industry trade show, this September,” Nakano continues. “I hope my presentation on this innovative new product will encourage interest from people across the industry.”
To a large degree, DIC’s focus on developing a cobalt-free drier technology targeting the EU reflects its belief that similarly strict regulations will eventually also be introduced in the United States and Japan. The Company also believes that cultivating forward-looking advanced technologies is important to providing peace of mind to domestic customers. “Whether it’s two years from now or 10, we want to make sure we are fully prepared. If we are competitive in the EU market today, it should put us in a good position to succeed in other countries and regions,” says Takamitsu Kuriyama.
So, what is ahead for DIC’s drier development program?
“In the future, the EU may also decide to regulate manganese. Our ultimate objective is thus to develop products that use even more sustainable raw materials,” clarifies Hiroaki Nakano. “It is a high hurdle, to be sure, but we are determined not to rest on our laurels, but rather to continue aiming higher.”
Driers are not well known because they are additives and thus invisible to the human eye. However, because driers significantly improve the productivity of coating and printing processes, their importance to these industries is immeasurable. Nakano describes the appeal of working on the development of such materials that really are unsung heroes. “Whether it is structures painted with attractively colored coatings or publications printed with vividly colored inks, colors significantly impact our daily lives and sensibilities. As people involved in the development of driers for coatings and inks, we also have a role to play. By advancing efforts to develop groundbreaking products such as cobalt-free driers and safer alternatives to currently used solvents, we will continue working to realize coatings and inks that add color and comfort to life, as well as deliver greater safety and peace of mind, while at the same time exerting less of an impact on the environment.”
All participants in this interview wore plastic face shields developed and manufactured by DIC Group company DIC Plastics, Inc., in response to the needs of the COVID-19 era.
DIC Plastics’ website is here (Japanese only).
DIC Color Guide® color sample book
DIC-N890 (cobalt blue) from the DIC Color Guide® Traditional Colors of Japan series
Derivation: Cobalt blue is a cobalt aluminate pigment derived from cobalt ore. While it is possible to create a wide range of organic pigments through synthetic organic chemistry, inorganic pigments like cobalt blue can only be obtained from inorganic metallic compounds.
Note: Interviews were conducted in July 2021. The content of this article has been approved by the interviewees.
