Abstract
KEYWORDS – bio-based, polyol, sustainable, high performance, polyurethane
ABSTRACT –
Polyurethanes have been used for many years to produce high-performance materials for the automotive industry such as coatings, adhesives, sealants and elastomers. Within Croda we set ourselves a goal to extend our range of existing polyols with a next generation, to meet the industry need for continuously increasing performance.
To understand these needs with respect to the required performance, a market survey has been conducted. This survey clearly showed that a novel polyol has to meet the following requirements:
• Matching the strength and hardness of current systems while boosting flexibility
• Equivalent durability to polycarbonate polyol
• Enhanced polymer flow for improved processing
• Strong chemical resistance (methanol, acid, caustic, petrol)
• Good adhesion to multiple substrates
Considering the use of polyurethanes in automotive applications, we also identified the global trend towards improved sustainability with renewable targets, light weight design, extended lifetimes and VOC reduction (e.g. solvent-free, UV curable and water-based systems).
In the development of these polyols, we based the building blocks on natural derived oils, addressing the need of increased renewability content. The polyols contain a branched, non-crystalline structure, which enhances wetting of the substrate and offers (low temperature) flexibility. Increasing the flexibility would normally imply a loss of strength; the novel polyols however exhibit good flexibility while having higher surface hardness and excellent strength. The hydrocarbon character imparts water repellence and facilitates the water evaporation of water-based coating in the pre-drying stage. An additional benefit of the hydrocarbon character is the good adhesion on a wide range of substrates such as steel, aluminium and plastics. Furthermore, the bio-based novel polyols offer a unique combination of hydrolytic, thermo-oxidative and UV stability, which is highly relevant for demanding applications such as sealants, electrical insulation especially for under the hood areas and other automotive applications.