CYMEL® U-216-10LF

The stability of formulated systems containing CYMEL® U-216-10LF resin can be enhanced by the addition of alcohols, amines or a combination of these. Low molecular weight primary alcohols such as ethanol or n-butanol are most effective. Recommended amines are TEA or DMEA at a concentration of 0.5-1.0% on total binder solids.

As with other urea-formaldehyde resins, CYMEL® U-216-10LF resin may not require the addition of an acid catalyst to the formulation in order to obtain effective cure. In many instances, the acidity of other formulation components is sufficient to catalyze reaction. If catalyst addition is required, then 0.5-1.0% of either CYCAT®® 4040 catalyst or CYCAT® 296-6 catalyst, based on weight of total binder solids, is recommended for normal bake schedules (15-20 minutes at 120-150°C).

CYMEL® U-216-10LF resin contains a combination of butoxymethyl and methylol functionalities, making it a very effective crosslinking agent for backbone polymers containing hydroxyl, carboxyl, and amide functionality. In addition to entering into crosslinking reactions, CYMEL® U-216-10LF resin also has a tendency toward self-condensation. Therefore, its practical equivalent weight, on a solids basis, is in the range of 200-280. Increasing the level of CYMEL® U-216-10LF resin in a coating formulation will generally increase the hardness and chemical resistance of the cured film, although higher levels may also increase brittleness. The optimum level in a particular formulation should always be determined experimentally.

CYMEL® U-216-10LF resin has a shelf life of 1440 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 an irreversible increase in viscosity.