New technical literature on Resyn Patch window adhesives, which provide the high tack required for high and ultra-high speed envelope window patching units, is available from National Adhesives. Resyn Patch window adhesives provide strong adhesion to polyestrene films, kraft, vellum or rag bond papers. Envelope converters can rely on the adhesives for consistent transfer without slippage or buckling. In addition, all adhesives contain UV indicators to provide simple and effective quality control under a black light. According to the data sheet, the adhesives stay cool in the gum box, minimizing the tendency to thicken over time, even on recirculation systems.