Session IV: Polyurethanes - Part 1
Chair: Edwin Hortelano, Ph.D., Director, UV and Waterborne Technology Platforms Coatings, Adhesives, and Sealants, Bayer MaterialScience LLC
Tuesday Morning, 9:00 a.m. – 12:30 p.m.
Breakout Room 213 B/C/D
With a huge variety of binder chemistries combinable with a growing number of polyisocyanate varieties, polyurethanes are one of the most versatile classes of organic coatings, and usually represent the high-performance range of applications. Research continues unabated to further increase the performance of polyurethane coatings, particularly in view of environmental legislation demands. Thus, the first of two sessions dedicated to PUR materials developments focuses mainly on research aiming at high-performing 1K and 2K waterborne PUR coatings, as well as new radiation curing systems. | ||
4.1 9:00 – 9:30 a.m. Taking Ultra Low VOC Polyurethane Dispersions to the Next Level of Performance Peter Schmitt*, William Corso, Christoph Irle, Bob Wade, Jan Weikard New formulations and procedures have been developed that result in ultra low and zero VOC polyurethane dispersions. These new products can be formulated into ultra low VOC coatings systems. Improving the properties of coatings from these systems is the subject of this paper. The chemistry behind these materials, including cross-linking mechanisms, will be presented. The cross-linking mechanisms include oxidative cure, UV cure, and cure with water-dispersible isocyanates. Improvement of properties through these reactions is demonstrated. | ||
| 4.2 9:30 – 10:00 a.m. Novel Waterborne Dispersion Technology for High Performance, Low VOC Coatings Charles Diehl*, Ray Drumright, Gary Spilman, Dow Coating Solutions Historically, high molecular weight polymers such as epoxies, polyurethanes, and alkyds, have been used to produce excellent quality solvent based coatings. The trend to lower VOCs has required the use of lower molecular weight polymers or oligomers, in order to achieve higher solids solventborne systems, as well as water reducible coatings. These lower molecular weights require the use of higher levels of crosslinker and result in compromised coating properties. A new continuous mechanical dispersion process technology has enabled the production of water based, high solids dispersions of polymers without compromising on polymer molecular weight. This process has not only enabled the dispersion of traditional coating binder resins, but also allows the dispersion of new polymers such as polyolefins. These dispersions can be produced without the use of any solvent, allowing extraordinary formulation latitude in the choice of additives for coalescence enhancement. Fundamentals of the dispersion process as well as performance of dispersion examples will be described. | ||
| 4.3 10:00 – 10:30 p.m. 1K Polyurethane Dispersions for Conventional 2K Applications Anthony Pajerski, Lubrizol Polyurethanes have gained a strong reputation for their excellent durability and resistance properties. This has led to applications in many higher performance areas, an example of which includes wood substrates and in particular wood flooring where high durability is required. In order to further enhance polyurethane coatings for flooring applications, crosslinking of the polymer is usually employed. Waterborne polyurethane dispersions (PUD’s) have been increasingly used versus more conventional solventborne types due to their improved environmental and user friendliness. However, crosslinking of the PUD is still often done using a secondary component; typically polyaziridine or polyisocyanate crosslinkers. The performance obtained with two component PUD’s has made them a popular choice for contractor applied wood floor finishes, but they have significant drawbacks of toxicity and limited pot-life. This paper will discuss how new self-crosslinking PUD’s can provide performance comparable to commercial 2K crosslinked systems for floor finish applications. 10:30 – 11:00 a.m. Networking: Refreshments & Coffee Break | ||
| 4.4 11:00 – 11:30 a.m. Improved Polyurethane Dispersions Using Non-ionic Diols Henrik Bernquist*, Petra Winberg, Konstantin Mpampos, Karina Ekvall, Rebecka Liedholm, Göran Ziegler, Kent Sörensen, Perstorp Specialty Chemicals AB, Sweden Most polyurethane dispersions are anionically stabilized using e.g. a dihydroxycarboxylic compound. In some applications it is, however, necessary to have improved electrolyte stability, e.g. good stability at lower pH, and improved shear stability. In these cases non-ionic stabilization or a combination of anionic and non-ionic stabilization is preferred. In this paper a non-ionic diol, which can be built into pendant positions in the polyurethane backbone, and thereby achieving efficient internal stabilization, is presented. A comparison to other types of non-ionic as well as anionic stabilization, including the tolerance of the resulting polyurethane dispersion against electrolytes, cold temperatures and shear forces, is made. Furthermore, the effect of the stabilizing segments, anionic as well as non-ionic, on the resistance of the final coating towards polar solvents is discussed. | ||
| 4.5 11:30 a.m. – 12:00 p.m. Waterborne Radiation Curable Polyurethanes Jonathan Shaw*, Jurgen Van Holen, Jon Shaw, Jean-Pierre Bleus, Michel Tielemans, Marc Decaux, Xavier Deruyttere, Cytec, USA Radiation curing (UV/EB) technology has been used for over 30 years in the industry, especially in wood and paper coatings as well as in printing inks; The high productivity and performance were the initial drivers to switch to this solvent free technology. Nowedays the ever more stringent regulation and the savings on energy are becoming as important for endusers. In this paper we will demonstrate the advantages of UV curable dispersions in water which are free of solvents and combine excellent stain, scratch and chemical resistance. Furthermore they can be tailored to have an excellent gloss. | ||
| 4.6 12:00 – 12:30 p.m. Self-Initiated UV-Curable Allyl Ether and Vinyl Ether Urethane Monomers Igor Khudyakov*, Joseph A. Leon, R. David Zopf, Bomar Specialties We prepared new urethane monomers capped by pentaerthrytol triallyl ether (TAE) as well as by other unsaturated ethers. Isophorone diisocyanate (IPDI) was used in these solventless reactions. The same monomers were UV-cured using both free-radical and cationic methods with the formation of films of different properties. Films based on TAE monomers (“hexa ene urethanes”, TAE-IPDI-TEA) demonstrate especially valuable properties. The cured products from capping of IPDI with multifunctional hydroxy acrylates and with TAE manifest good adhesion and toughness. IPDI was reacted also with a blend of unsaturated ethers and tri- or tetrafunctional thiols. Obtained monomers are self-initiated; they do not require any photoinitiator under UV-cure. Contrary to the well-studied “thiol-ene” chemistry, where thiol and ene are individual reagents, our monomers have two reactive group bound together. | ||
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