Bayflex® WR-20

Component A (MDI prepolymer) must be stored in tightly closed containers and protected from contamination with moisture and other foreign substances, which can adversely affect processing. It will react slowly with water to form ureas and carbon dioxide gas, which may cause sealed containers to expand and rupture. The headspace of partially filled containers should be blanketed with dry nitrogen. Storage temperatures should be maintained between 24° and 30°C (75° and 86°F). Under these conditions, Component A will remain clear for up to six months. Within this range, lower storage temperatures will maximize the storage life of the product. Component A must not be allowed to freeze. Exposure to temperatures less than 15°C (59°F), even for short periods of time, can result in the formation of solid material. During the winter months, appropriate precautions must be taken during shipment and storage. Prolonged storage of solid or partially solid Component A may result in the formation of MDI dimer in amounts which exceed its solubility in the prepolymer at normal storage temperatures. This can make the product unusable.
If solids should form because of exposure of Component A to lower temperatures, it may be possible to reliquify the product by heating. Use a well-ventilated oven for the minimum time necessary to render it clear. The temperature of the product should not exceed 60°C (140°F). Agitation or drum rollers are recommended to avoid excessive local heating, which will degrade the prepolymer. Significant amounts of MDI dimer may form during the heating process. As a result, the remelted prepolymer may be cloudy, and the processing behavior and properties of the final product may be affected.
Component B (polyol) is normally shipped in 55-gallon lined steel drums. The material is hygroscopic and should be kept in tightly closed containers to prevent contamination with atm ... text to long! (max 2000 characters)