Session X: Polyurethanes - Part 2
Chair: Charles Diehl, Development Scientist, Dow Coating Solutions, The Dow Chemical Company
Wednesday Morning, 9:00 a.m. – 12:30 p.m.
Breakout Room 213 B/C/D
The second PUR session of the conference highlights recent research performed to develop improved low VOC high solid formulations based on new chemistries such as oxazolidines, or highly functional polyisocyanates. Novel low-bake powder polyurethane coating systems promise to enable the convenient coating of temperature sensitive materials. The session also puts forward new binders materials that reduce the concern for isocyanate monomer content. | ||
10.1 9:00 – 9:30 a.m. A Novel Line of Air Drying Resins to Meet VOCs Samuel P. Morell, S.P Morell and Company A new line of oxidizable, phenolic based, urethanes (OPU) have recently been introduced that will aid the formulator of solventborne coatings to meet increasingly restrictive VOC regulations. Additionally, the use of these novel, unsaturated, air drying resins will improve upon the properties obtained from conventional solvenborne systems and includes reduced dry time, enhanced toughness, mar resistance, high gloss, and improved chemical resistance. This presentation will briefly review how the chemistry of alkyds, phenolics, and urethanes contribute to the application and performance properties of conventional solvenborne systems and how this new resin technology combines and transforms all three of these chemistries to produce improved results and satisfy VOC compliance. | ||
| 10.2 9:30 – 10:00 a.m. Improved Properties Offered by Higher-Functionality Aliphatic Polyisocyanates Patricia Jacobs*, Markus Mechtel, Karen Henderson, Bayer MaterialScience Light stable aliphatic polyisocyanates are well known in the industry as crosslinkers for high performance coatings applications. Two-component polyurethane coatings can be adjusted to the meet the requirements of multiple market areas and substrates. They set the standard for appearance, durability, chemical resistance with the unique combination of toughness and flexibility that no other coatings chemistry can match. The newest addition to the list of commercially available polyisocyanates is an HDI-based trimer/allophanate crosslinker with functionality greater than 4.0, achieved without sacrificing a workable viscosity. The greater crosslink density made possible by these materials results in coatings with even higher performance properties. The performance of scratch resistant coatings for metal, plastic and wood substrates based on these higher functionality aliphatic polyisocyanates will be discussed. | ||
| 10.3 10:00 – 10:30 p.m. Developing Polyurethane Coatings with Low or No Free Isocyanate Richard Jones, Baxenden Chemicals Ltd, Great Britain Isocyanates are one of the fundamental building blocks for polyurethanes. However the hazards associated with handling monomeric isocyanate make them unacceptable for some potential users. Methods of producing polyurethane prepolymers with low free monomer and new developments preparing urethanes without using isocyanate are presented. Not only do these newer materials provide access to urethanes which are “isocyanate free“, but they allow chemists to access new raw materials for coating formulation. 10:30 – 11:00 a.m. Networking: Refreshments & Coffee Break | ||
| 10.4 11:00 – 11:30 a.m. Empowering Powder – Polyurethanes for Low Temperature Cure Powder Coatings Corey King*, Werner Grenda, Emmanouil Spyrou, Evonik Degussa Corporation Polyurethane powder coatings are well-known for their high weatherability, excellent chemical resistance and good physical properties. This technology has previously required cure temperatures of 180-200°C to crosslink effectively to provide these superior characteristics. A new class of catalysts has been found that enables cure of uretdiones (internally-blocked polyisocyanates) as low as 130°C, and recent developments have been made to improve long term powder storage stability for these systems. These advances open up many new applications for powder coatings requiring the excellent properties of polyurethanes but with lower temperature cure. | ||
| 10.5 11:30 a.m. – 12:00 p.m. Oxazolidines – Enhancing Productivity and Performance in Polyurethane Coatings and Paints Shuyuan Liu, Industrial Copolymers Ltd, Great Britain With the increasing awareness of climate change, there is much effort by the coating industry to develop new technologies that are focused on increasing productivity, whilst reducing the carbon footprint and VOCs in order to protect our environment. The ever more stringent VOC legislations also present a huge practical challenge to the coating formulators. The use of a reactive diluent is one of many approaches that can be used to tackle the VOC problem. In this paper we will provide an up-to-date comprehensive study on oxazolidines in comparison to other types of reactive diluents in 2k polyurethane coatings. The study demonstrates that oxazolidines offer great benefit in their versatility in wide range of applications. They can not only reduce the level of VOC, but also improve the productivity in the film forming process and enhance the final film performance. The versatility of oxazolidine chemistry in other PU applications will also be discussed briefly. | ||
| 10.6 12:00 – 12:30 p.m. The Latest Developments in Light-Stable Sprayable Thick Film Coatings David Zielinski, Bayer MaterialScience LLC Sprayable thick film coatings (TFC) based on polyurea and polyurethane chemistries have increased in use since their introduction in the late 1980s. These TFCs have proven that a rapid cure spray TFC can provide a seamless protective barrier to just about any surface you can coat. One drawback to the established technology is that they are typically based on non-light stable “aromatic“ polyisocyanates which leads to poor color retention and weathering resistance. In addition, these systems usually contain monomeric di-isocyanates, which lead to increased industrial hygiene concerns during application. More recently, light stable “aliphatic” polyisocyanate based TFCs have been developed that address the color and weathering resistance needs, but may still contain monomeric di-isocyanates. This paper will discuss the latest aliphatic polyisocyanates and formulations using them that have reduced levels of monomeric di-isocyanate yet are still fast curing and VOC free. | ||
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