Adhesives, fundamental in bonding materials for various industrial applications, often consist of polymers like polyurethane. Typically manufactured from polyols and isocyanates, the reactive isocyanate component can be harmful to health before curing. Consequently, the European Chemicals Agency has imposed restrictions on isocyanate usage and mandates training for its users to ensure safe handling.
In her doctoral thesis, MSc (Tech.) Soilikki Kotanen investigated reactive adhesives and hot-melt adhesives. The research focused on the development of non-isocyanate polyurethane (NIPU) materials. Kotanen, a graduate from Tampere University, was inspired to pursue her doctoral dissertation while working as the RDI Manager for polyurethane adhesives at Kiilto.
The research investigated the production of NIPU using two different reaction methods: polyaddition and polycondensation. Kotanen studied the impact of the raw materials on the progress of the reaction.
“The commercialization of these alternative methods is often hindered by low reactivity and the limited availability of raw materials on an industrial scale. In the reactive adhesive tests, the materials that reacted quickly at room temperature and exhibited promising bonding strength were identified,” Kotanen says.
According to Kotanen's findings, studied materials showed limited water resistance compared to traditional polyurethanes, necessitating further research or specific application areas. The disseration provides insight into how alternative reaction mechanisms affect the properties of the final product.
“Although current raw materials can be handled safely with proper protective gear, exploring alternative methods is essential. This aims us to develop even safer solutions and identify application areas for new types of adhesives,” states Kotanen.
"The results show that these promising NIPU materials can be further developed into effective adhesives. We need to investigate how additives and auxiliaries affect the adhesive properties,” Kotanen adds.
Soilikki Kotanen works as a RDI Director at Kiilto in Tampere. The research was conducted at Kiilto Research, Development, and Innovation Center and in collaboration with the VTT Beccu project funded by Business Finland.
Public defence on Friday 30 August
The doctoral dissertation of M.Sc. Soilikki Kotanen in the field of Engineering and Natural Sciences titled Feasibility of Non-Isocyanate Polyurethanes as Industrial Adhesives will be publicly examined at the Faculty of Engineering and Natural Sciences at Tampere University at 12:00 on Friday 30 August 2024. The venue is auditorium Pieni Sali 1 of the Festia Building (address: Korkeakoulunkatu 8, Tampere). The Opponents will be Professor Carl-Eric Wilen, Åbo Akademi and Professor Eva Malström Jonsson KTH Royal Institute of Sweden. The Custos will be Professor Essi Sarlin from the Faculty of Engineering and Natural Sciences at Tampere University.
The doctoral dissertation is available online
Photograph: Jonne Renvall/Tampere University