Epoxy Curing Agents

New phenalkamide, LITE 3070, provides fast dry times at room temperature while also delivering a long pot life and working time. This epoxy curing agent can be formulated in zero and low VOC epoxy systems due to its low viscosity. LITE 3070 is suitable for coatings, adhesives and any epoxy application that require good weatherability and protection coupled with good reactivity and friendly application and handling properties. When formulated in high solids and solvent free coatings, LITE 3070 demonstrated excellent anticorrosion performance as seen in salt spray tests. Moreover, this material provides very good intercoat adhesion even at low temperature and high humidity, and good adhesion to metal substrates and flexibility. As with other phenalkamides, LITE 3070 delivers low yellowing upon UV exposure.

Many protective coatings systems are comprised of a primer and a topcoat. Commonly, the coating application takes place at a job site without control of environmental conditions such as temperature and humidity. Even though most coatings show good cure properties and intercoat adhesion at standard application conditions, they may fail if cured at lower temperatures specially in combination with higher humidity. Phenalkamide LITE 3117 provides excellent cure speed even at 5°C allowing formulators to continue the work in colder winter days. In addition, LITE 3117 retains excellent intercoat adhesion to topcoats when cured at 5°C/ 90-85% R.H. for only 2 days.

Typically, epoxy primers fully dry prior to being top coated with another coating layer. However, it is not unusual for applicators to add a second layer of coating before the primer has completely cured. For instance, polyurethanes are commonly applied over epoxy systems after short intervals in automotive refinish and transportation markets. This quick recoatability increases productivity and minimizes asset downtime. In this type of application referred to as wet-on-wet recoat, the shorter the recoat interval the better. Some projects require epoxy curing agents that can provide recoat times as short as 15-30 minutes to the epoxy coatings. If the epoxy + polyurethane system is not properly designed, film appearance can be compromised. As a result, an effect known as “die back” causes lower gloss of the polyurethane top coat.

Our evaluations have shown primers based on many of our phenalkamines and phenalkamides deliver very fast recoat times without hurting the film appearance. Also, they still provide excellent corrosion protection to the substrate as shown in the graphs below.