Coating Additives Coating Additives | ||||||||
| NACURE® & K-CURE® ACID AND BLOCKED ACID CATALYSTS Why Use Catalysts? In order to meet the environmental demands of lower solvent emissions, much of today's high solids and waterborne coatings are based upon low molecular weight resins and amino-formaldehyde crosslinkers. Conversion of these systems into tough, chemically resistant, high performance films at reasonable cure temperatures requires the use of catalysts. Common backbone resins in these formulations include acrylics, alkyds, epoxies and polyesters. Typical amino crosslinking agents include melamines, ureas, glycolurils and benzoguanamines. Reaction of the backbone resin with an amino crosslinker can be greatly enhanced by the addition of the appropriate catalyst. As a result, the reaction between the functional groups of the resin and the crosslinker can be effectively controlled, thus offering:
Additionally, the proper choice of catalyst can impart specific desirable properties to the coating including:
King Industries was a pioneer in the development of catalysts and today offers the most complete line of acid and blocked acid (latent) catalysts available. While acid catalysts provide the fastest cure and lower curing temperatures, blocked catalysts are typically chosen for systems requiring greater package stability. In addition, troublesome catalyst-pigment interaction is reduced or eliminated. Suggested Starting Levels Acid Catalysts (Table 1) lists acid catalysts and (Table 3) blocked acid catalysts to fulfill your specific needs. (Table 2) represents the various cure profiles of the acid catalyst based upon a 30 minute cure schedule for a typical Resin/HMMM (75/25 ratio) coating.
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