Gold-colored finishes makes glass, china and perfume bottles look precious. For high quality gold decors, the gold color must be cured reliably and with a brilliant shine. This can be achieved with infrared or ultraviolet radiation, depending on the color. A low temperature paint from the Precious Colors Division of Heraeus can be cured using Heraeus Noblelight’s Max infrared oven at temperatures between 392 and 482°F (200 and 250°C).
Tests with the infrared oven out at the Heraeus Applications Center showed that processing times of less than one minute in the Heraeus oven were sufficient to meet the required specifications. The company credits the MAX oven’s process chamber, which is lined with QRC quartz material. This ensures a diffuse and homogeneous distribution of the radiation from all directions. In this way, even components with walls thicker than 0.197" (5 mm) can be heated quickly and homogeneously.
The new infrared ovens combine infrared radiation with convection and optimal reflection. According to the company, they are precisely adjusted to the heating process, which helps increase capacity and improve quality. Like all infrared ovens, the emitters apply heat in a directed manner. Heat is applied only where it is needed and only as long as required for the process.
The low curing temperatures enable — for the first time, according to Heraeus — the combination of a noble metal preparation with organic colors. Because the Heraeus Low Temperature Gold is a preparation on an aqueous basis without the use of environmentally hazardous organic solvents, environmentally harmful emissions are not produced during processing. Moreover, the low curing temperatures enable substantial energy savings and considerably shorter through-put times in the curing ovens.
The company also released a new color series of coatings that can be cured efficiently with UV LEDs. In the UV curing process of polymerization, photo-initiators are activated by intensive UV light to cross-link them within fractions of a second. With that, paints or colors are cured quickly and without heat, so the surface is immediately dry and can continue to the next process.