Mondur® M (FLAKED)

Mondur M (Flaked) diisocyanate can be used in the production of solid polyurethane elastomers, adhesives, coatings, and in intermediate polyurethane products. As with any product, use of Mondur M (Flaked) in a given application must be tested (including but not limited to field testing) in advance by the user to determine suitability.

Mondur M (Flaked) diisocyanate must be stored in tightly closed containers and protected from contamination with moisture and foreign substances that can adversely affect processing. Contamination can result in the formation of solids, the evolution of gas, and/or significant amount of heat. Mondur M (Flaked) diisocyanate will react with water to form ureas and liberate carbon dioxide gas, which may cause sealed containers to expand and rupture. Partially filled containers should be blanketed with dry nitrogen.Dimer Formation: During storage, Mondur M (Flaked) diisocyanate slowly reacts to form self-condensation products known as MDI dimer. Dimer is undesirable because it is only slightly soluble in the molten product and in time will cause turbidity and/or form a solid precipitate. Dimer formation occurs in Mondur M (Flaked) diisocyanate and the rate is determined by the storage temperature. This is the critical factor controlling the storage life of Mondur M (Flaked) diisocyanate.To avoid rapid dimer formation, and a significant shortened storage life, Mondur M (Flaked) diisocyanate must not be allowed to remain at temperatures between 20° and 39°C (68° and 102°F). Dimer forms in solid Mondur M(Flaked) diisocyanate at a very rapid rate somewhat below its melting point of 39°C (102°F). If solid Mondur M (Flaked) diisocyanate is allowed to remain at this temperature for several hours, it can form enough dimer to become unusable. This can occur, for example, when a drum or vessel of liquid isocyanate is allowed to slowly freeze due to exposure to ambient temperature.Storage Temperature for Mondur M (Flaked) diisocyanate: Store fused Mondur M (Flaked) diisocyanate at 5°C (41°F) or lower, which will provide a storage life of about three months. At temperatures of -20°C max (-4°F max), the product can be stored up to six months. Storage temperatures up to 15°C (59°F) are possible, if the correspondingly shorter storage life is acceptable. Strictly avoid the storage of solid Mondur M (Flaked) diisocyanate between 20° and 39°C (68° and 102°F) because the formation of dimer is very rapid at these higher temperatures.Melting Mondur M (Flaked) diisocyanate: Mondur M (Flaked) diisocyanate is especially convenient for smaller operations, since the flaked material may be easily transferred to the appropriate vessel without prior melting. It is recommended that Mondur M (Flaked) diisocyanate be melted in heat jacketed vessels equipped with an agitator. This will ensure rapid melting and uniform heating with minimum formation of MDI dimer. Proper ventilation must be used when melting material. When melted, use the entire contents of the container, if possible. Otherwise, blanket the remaining Mondur M (Flaked) diisocyanate with nitrogen and store at a temperature of 41° to 44°C (106° to 111°F). Do not attempt to refreeze melted Mondur M (Flaked) diisocyanate.During melting, monitor the drums for abnormalities, particularly swelling, and discontinue heating should any be observed. Swollen drums are potentially dangerous and must be handled only by trained personnel. Contact Covestro's Product Safety Department for guidelines on handling swollen drums. See Safety Data Sheet for emergency telephone numbers.If no abnormalities are observed, open the drums of melted Mondur M (Flaked) diisocyanate in a well-ventilated area. Appropriate personal protection equipment must be used (see Safety Data Sheet). Remove any moisture from the top of the drum and open the bung slowly to relieve pressure build-up that may have occurred during the melting process.If moisture contamination has occurred, do not attempt to melt the product, because the moisture will react with the isocyanate and result in a dangerous pressure build-up of carbon dioxide in a closed system.Do not use electric heating devices or any type of high temperature equipment for melting Mondur M (Flaked) diisocyanate. High temperatures can cause decomposition of the isocyanate and the formation of gases which can build up pressure in closed containers and cause them to rupture, possibly resulting in serious injury.It is possible to filter small amounts of dimer from Mondur M (Flaked) diisocyanate. This is typically done when no turbidity or particulates can be tolerated in the process. Contact your Covestro representative for specific filter equipment recommendations based on your processing needs. Filtration cannot solve a dimer problem. When Mondur M (Flaked) diisocyanate has reached the end of its storage life, indicated by a significant formation of solids, the only really satisfactory solution is to rapidly use the remaining product.