Liquid MDIs Get Antifreeze Treatment.Two new isocyanates reportedly overcome the problem of liquefied MDI (1) (Multiple Document Interface) A Windows function that allows an application to display and lets the user work with more than one document at the same time. freezing during cold weather. Mondur MA-2300 and PF-LT from Bayer Corp.'s Polyurethanes Div. in Pittsburgh are liquid MDI adducts with significantly improved freeze stability over Bayer's Mondur PF modified monomeric monomeric /mono·mer·ic/ (mon?o-mer´ik) 1. pertaining to, composed of, or affecting a single segment. 2. in genetics, determined by a gene or genes at a single locus. MDI. They are aimed at PUR elastomers, integral-skin foams, RIM, and spray systems. Both products have 23% isocyanate i·so·cy·a·nate n. Any of a family of nitrogenous chemicals that are used in industry and can cause respiratory disorders, especially asthma, if inhaled. content, like Mondur PF. However, a new modification process lowers the freezing points freezing point Temperature at which a liquid becomes a solid. When the pressure surrounding the liquid is increased, the freezing point is raised. The addition of some solids can lower the freezing point of a liquid, a principle used when salt is applied to melt ice on of MA-2300 and PF-LT to 41 F and 32 F, respectively, compared with 59 F for Mondur PF. In typical one-shot PUR formulations, Mondur PF-LT and PF reportedly produce nearly identical reaction profiles, pot life, and exotherm. MA-2300 shows longer pot life and lower exotherm than either PF-LT or PF. Bayer says physical properties of PUR products made with the new isocyanates are at least as good as those of products made with Mondur PF. |
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