A way to incorporate vegetable oils in polyether polyol production with only a few modifications to existing plant has been developed by Bayer MaterialScience and is being presented in a paper at the Utech polyurethanes conference and exhibition to be held in Maastricht in the Netherlands over the next few days.
The company says it can make polyols with 53 – 68 per cent content from renewable resources, with properties “at least as good as polyols made exclusively from petroleum”. According to Bayer, when used to make rigid foams for thermal insulation “the quality of the foams, which contain 8 to 15 per cent renewable raw materials, matches or even surpasses that of conventional products.”
A key consideration in the use of fatty acids to make natural oil polyols (NOPs) is that they can be derived from all types of oil-producing plants. So oils from plants native to a specific region are suitable, and the raw materials need not be transported over long distances.
As Dr Klaus Lorenz reports in his Utech paper, Bayer researchers in Germany have tested polyurethane rigid foams derived from NOPs for refrigerators to determine their physical, processing and insulating properties. “The results show that the demoulding characteristics of NOP-based foams are just as excellent as those of conventional state-of-the-art systems. They also are on par with conventional foams when it comes to mechanical loading and thermal insulation properties.” He says that they meet the requirements of energy efficiency class A+ and in some cases, the use of NOPs in polyol blends can improve performance by increasing the solubility of the blowing agent and allowing more flexibility in formulating the foams.
NOPs have also been tested in the USA for polyisocyanurate rigid foams such as for laminated boardstock used as thermal building insulation. One product has gone commercial and is on sale in the NAFTA region as Multranol 8160. It is a component of a rigid foam system used in the new Eco-Max product line from Rmax, a US manufacturer of PIR thermal insulation materials. Multranol 8160 enables companies to make PIR rigid foams classified as ‘bio-based’ according to the criteria of the United States Department of Agriculture, which adds a commercial incentive: a regulation issued by the US government says that government agencies are to give preference to bio-based products over those made from petrochemical raw materials when purchasing supplies. Rigid foam for thermal building insulation is being regarded as bio-based if the percentage of carbon from renewable resources is equal to or exceeds 7 per cent.
Dow Chemical in the USA has also been working on natural oil polyols and in 2007 commercialised its Renuva Renewable Resource Technology process for making polyols from soybean oil. Also in 2007 DuPont introduced its Cerenol family of polyetherdiols made from Bio-PDO (1,3 propanediol) sourced from sugar.