The new issue 3/2019 of PU Magazine International has been published!
In this new issue you can read about past fairs and conferences such as Foam Expo North America in Novi, MI, one of the most important trade shows for the foam industry, the European Coatings Show in Nuremberg, Germany, the leading trade fair for the global coatings industry, and the PSE Europe, the international Expo for PU Solutions.
Featured technical articles are:
- Novel phosphorus-based flame retardants for rigid polyurethane foams
(H. Tebbe, C. Simpson, Lanxess)
An increasing interest in rigid polyurethane foam for insulation materials is expected due to the world wide growing awareness of climate change and energy consumption. Related to this development, the fire safety in building and construction applications will also gain more attention. In order to meet these requirements various flame retardants are used in rigid polyurethane foams. One of the most widely used groups of flame retardants is based on phosphorus. This includes chlorinated phosphate esters and halogen free compounds. In this paper, novel phosphorus based flame retardants developed by Lanxess will be introduced. The performance of these products in rigid polyurethane foam formulations will be shown in comparison to other established flame retardants. Within the scope of the comparison, the effectiveness of the novel retardants in fire tests will be shown. Furthermore, the impact of the products on processing, stability, and foam properties will be discussed. The results indicate that the novel flame retardants can help to match the requirements for rigid polyurethane foams.
- Potential analysis of CO2-based, crosslinkable polyols for polyurethane components
(C. Hopmann, D. Schneider, N. Bergmann, F. Kessler, J. Norwig, Institute for Plastics Processing (IKV) at RWTH Aachen University and Covestro AG)
Carbon dioxide (CO2) can be an attractive alternative to the utilization of fossil-based resources in polymer production. In recent years, it has been demonstrated that significant amounts of CO2 can be covalently bound into the polymer backbone of polyols, if suitable catalysts are used. By building in CO2 and other monomers, the molecular structure can be modified in a way that the spectrum of properties of the polyol and polyurethanes made thereof can be extended compared to conventional polyurethane (PU) systems. In order to analyse the potential of CO2-based polyols for PU components, the Institute for Plastics Processing (IKV) at RWTH Aachen University and Covestro AG, Leverkusen, Germany, carried out a comprehensive analysis of product properties of novel CO2 polyols in the framework of a publicly funded research project. Using a commercial isocyanate as reaction partner, more than 30 different polyols were analysed with regard to their processing characteristics and material properties of the PU. Empirical formulas were derived to predict these properties. A set of suited polyols was chosen for more in-depth analyses, for which the composition of polyols and crosslinkers was varied. The resulting polyurethanes were characterized regarding hardness, tensile properties, bursting pressure and damping properties (rebound capacity). This publication presents an evaluation of CO2-borne PU for compact damping elements.
- An insight into insulation performance for HFO blown PIR systems
(Y. Nakashima, H. Inohara, K. Yamamoto, Tosoh Corporation)
Rigid foam used as building materials require both incombustibility and heat insulation properties for fire safety and energy efficiency. Polyisocyanurate (PIR) foam shows excellent flame retardancy compared to polyurethane (PU) foam. On the other hand it is difficult to maintain heat insulating performance for a long time. Therefore in this study, we measured aging of thermal conductivity on laminate board of PIR foam using hydrofluoro-olefin (HFO) as a blowing agent which has high insulation performance and is environmental friendly and also investigated the aging mechanism. It was confirmed that there were three stages in aging of thermal conductivity on PIR board. In an initial stage (Stage 1), thermal conductivity increased rapidly. In middle stage (Stage 2), the aging of thermal conductivity was very slight. And in later stage (Stage 3), the thermal conductivity started to increase again. Furthermore, the cause of the aging at each stage was analyzed in detail. As the result, the aging of thermal conductivity was caused by three factors, which were carbon dioxide generation after demolding, moisture absorption and diffusion of gases. These factors were correlated with the amount of NCO groups remaining in the resin, polyol structures and cell sizes of the foams. Finally, we developed a novel isocyanate, which was effective for cell size control and reduction of residual NCO group content. The optimized PIR laminate board maintained about 95 % of the thermal insulation property for one year after production.
- Fast demolding technology via new chemistries for insulation foam in appliances
(S. L. Aprahamian, M. S. Super, R. Albers, Covestro)
As the appliance industry becomes increasingly competitive, refrigerator and freezer Original Equipment Manufacturers (OEMs) are challenged with managing changing energy standards as well as the need to master cost, quality, and productivity in their manufacturing facilities. In particular, they need to improve manufacturing productivity and reduce the cycle times for production of the cabinets in order to maximize the capacity utilization of their plants. The development of polyurethane insulating foam that allows the foamed refrigerator cabinet to be demolded faster can help address this challenge. Optimizing additive and catalyst packages and improvements in foam processing technologies have led to significant advances in reducing the demold times, but novel chemical approaches are now required to further reduce demold times. Covestro has new polyol and isocyanate chemistries that allow for the development of customized polyurethane foam systems that meet the demands of OEMs for faster demolding systems. This innovative, fast-demolding technology allows OEMs to produce cabinets with improved production efficiency without impacting the energy efficiency or other important quality parameters of the refrigerator itself. Innovative solutions from Covestro help the appliance industry tackle some of their most critical challenges. Covestro will now introduce these innovative solutions into the marketplace as part of our commitment to improve its offerings to society and constantly reduce its impact on the environment, while continuing to deliver value to shareholders.
- Novel nitrogen containing aromatic polyols for rigid polyurethane foams
(G. Viswanathan, P. Kukkala, V. Malhotra, I. Sendijarevic, Hexion Inc. and Troy Polymers Inc.)
A novel nitrogen containing polyol with high aromaticity and functionality, Resonance TL, was evaluated in model rigid polyurethane foams using a design of experiments (DoE) approach. The polyols used in the study were an aromatic polyester, Mannich, a sugar-based polyether, and a Resonance TL. The levels of each of these polyols were varied, whilst the aromatic polyester polyol was kept constant. The effects of changing polyols on the polyurethane foam reactivity and physical properties were assessed and specific trends were identified. Resonance TL significantly accelerated the foaming reactivity compared to sugar-based polyether and conventional Mannich polyols. The use of Resonance TL at 30 % loading in the total B-side formulation and without the Mannich or the polyether polyols resulted in self-extinguishing (without the addition of fire retardants) and dimensionally stable foams. Hence, Resonance TL can help minimize the use of volatile amine catalysts, as well as Mannich and polyether polyols. This could lead to simplified and enhanced polyurethane systems for a variety of applications.
- Sustainable pathway to plastic waste management: Safe incineration and energy extraction
(B. L. Kaul, MCA Technologies GmbH)
Plastics are to be characterized as solid fuels, derived from combustible materials. The most logical procedure of their ultimate disposal should be by incineration in closed systems. In this process, it should be possible to generate useful energy as well. For a safe, environmentally friendly (generation of less pollutants, especially nitrogen oxides) and an efficient energy extraction during waste incineration, the combustion process needs to be conducted under controlled conditions, preferably at low temperatures. MCA Technologies GmbH in Switzerland has developed an environmentally friendly technology, which on one hand imparts a sustainable safety to plastics in the event of fire during their use, and on the other hand, ultimately enables their environmentally friendly disposal as waste, and thereby simultaneous generation of usable energy. The technology is also intended to safeguard against open waste burning of plastics practiced in many countries.
Further information about the new issue at https://www.gupta-verlag.com/magazines/pu-magazine-international/03-2019.