CYMEL® U-662

CYMEL® U-662 resin is a very effective crosslinking agent for backbone polymer resins containing hydroxyl functional groups, such as alkyd, polyester or acrylic resins. The optimum level of CYMEL® U-662 resin in an acid curing wood coating formulation should be in the range of 25-35% on total resin solids. To obtain coatings with optimum resistance properties, addition of a melamine resin, such as CYMEL® MB-98 resin or CYMEL® 304 resin, at levels of 5-10% on total resin solids is recommended.

CYMEL® U-662 resin responds to both weak acids and sulfonic acid catalysts, like CYCAT®® 4040 catalyst. Generally, 6-10% CYCAT® 4040 catalyst on total resin solids of the formulation is sufficient to obtain fast drying behavior at room temperature.

CYMEL® U-662 resin has a shelf life of 720 days from date of manufacture when stored at temperatures below 32°C. Although low temperatures are not detrimental to stability, the viscosity of the product will increase making the resin more difficult to pump or pour. Product viscosity can be returned to normal by gentle warming, however, care should be taken to avoid excessive localized heating as this can cause polymerization.

To extend catalyzed pot life of the formulation, addition of primary alcohols, such as n-butanol and ethanol, is required at concentrations of 10-25% on total resin solids. Faster evaporating alcohols will improve speed of dry.