Objective
The goal of the project is to produce new alternative high-solid, isocyanate-free materials to substitute polyurethane paints.
A new alternative isocyanate free class of paint, aimed at replacing the high performance systems, has now become necessary for mass transport applications in order to obtain the double environmental advantage of:
the removal of isocyanate;
the reduction in emission of volatile organic compounds (VOC). Based on a new chemistry using the chemical reaction between anhydride tipped acrylic and hydroxylated backbones, new polymers (high functionality, low or medium molecular weight) have been developed as an alternative to the typical isocyanate hydroxyl polymer (polyurethanes) commonly used. The target of lowering the VOC leads to the polymer molecular weight optimization (eg by a bimodal concept). New systems have been produced and selected on the basis of the assessment of the polymers in terms of performance (crosslink density, glass transition temperature) and assessment against selected specifications and predictive toxicity. Several clear coats were successfully prepared with a complete agreement with the railway and aeronautical specification. Starting from one of the best systems, a white glossy paint has been developed and scaled up successfully. The new isocyanate free paint meets almost all the requirements of the specifications, except for properties depending on the crosslink density which is not sufficient for severe tests such as hot fluid resistance. Nevertheless, the developed paint;
shows good properties when cured at 70 C and can be used for small or medium assemblies in the aeronautical or railway sectors;
is close to the objectives (ie curing at room temperature);
has allowed the development of more than 20 high performance systems from this new chemistry based on high functionality anhydride and polyol polymers used as isocyanate free binders for paints, gives with some solvents a reduced VOC slightly higher than the specification. These binders (or clear coats) meet the specifications, including fluid resistance tests. The drying time, however, is twice as long as for current paints.
The manufacture and use of paint has significant environmental impacts. The high performance paint sector is the most demanding in terms of application requirements and film properties. Consequently the development of new less toxic products with reduced levels of solvent emission for this sector has become a crucial issue.
Based on novel non-isocyanate, curing chemistry, new polymers will be produced to formulate paints with performance levels similar to those of currently used two-component polyurethanes but showing a lower toxicity level.
After completion of the research on basic polymers, they will be adapted to produce a development formulation paint which should meet the requirements of the general industry as well as the automobile, railway and aerospace sectors.
Coordinator
92152 Suresnes
France
Participants (3)
76600 Le Havre
30026 Portogruaro Venezia
2 Dublin
