subject: Moisture Scavenger: A Key Component In Low-voc Urethane Performance [print this page] Moisture Contamination is generally associated with outdoor industrial coatings. It is a prime concern in marine coatings exposed to moisture during application, such as bridges and offshore oil platforms. Moisture can drastically affect all high-performance urethane coatings. Moisture Scavenger is used to enhance the life of urethane coating performance by providing more stability during operations.
However, moisture has generally been considered as an irritant with low-solids urethane coatings; it becomes a major issue with their high-solids counterparts. Moisture stored in these coatings can reflect in stability problems such as downglossing and pinholing. Moreover, it drastically reduces the product life.
Moisture is induced to these urethane coatings in the form of dissolved water in solvents and polyols, absorbed water in fillers and pigments, and humidity from the atmosphere. Because a higher concentration of pigment is included in high-solids coatings, this type of coating results into a higher degree of moisture contamination than low-solid products.
Moisture Scavenger helps reduces the problem of moisture contamination of polyurethanes as they are less toxic and fast reactants. If this moisture contamination is not removed from a urethane coating it can react with the formulation isocyanates to form carbon dioxide (CO2) and amines. Amines can then react with isocyanates to form urea. These by-products severely affect different coatings in various ways.
Removal of moisture is essential to produce polyurethane coatings systems. Due to the reactivity of isocyanates with water in urethane systems, the level of moisture leads to poor shelf life in urethane coatings.
There are a number of physical and chemical treatments applied to urethane raw materials and formulated systems in order to reduce moisture. Some solutions such as vacuum extraction or high temperature drying are expensive and short-term solutions. To overcome this problem, manufactures occasionally use moisture scavengers capable of removing moisture from a system.
Incorez is a specialist manufacturer of oxazolidines, waterborne epoxy curing agents and waterborne polyurethane dispersions. The other products are Moisture Scavenger, latest curing agents, and reactive diluents.
