CYMEL® U-227-8

The stability of formulated systems containing CYMEL® U-227-8 Resin can be enhanced by the addition of alcohols, amines, or a combination of these. Low molecular weight primary alcohols such as ethanol and n-butanol are most effective. Recommended amines are TEA, DMEA, or 2-AMP at a concentration of 0.5-1.0% on total binder solids.

• CYMEL® U-227-8 Resin may not require the addition of an acid catalyst to the formulation in order to obtain effective cure, as with other urea-formaldehyde resins. 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-227-8 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-227-8 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-227-8 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-227-8 Resin has a shelf life of 4 years from the date of manufacture when stored at temperatures between 5°C and 30°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.
• CYMEL® U-227-8 Resin viscosity can be returned to normal by gentle re-warming; however, care should be taken to avoid excessive localized heating as this can cause an irreversible increase in viscosity.