Optical Brightener OB-1 is widely recognized as a benchmark product in the plastics industry. Renowned for its exceptional thermal stability, it is particularly well-suited for high-temperature thermosol pad-dyeing processes. It not only significantly enhances the whiteness of polyester fibers and their blends with cotton and other synthetic fibers, but also delivers outstanding performance in a broad range of plastic substrates, including ABS, PS, HIPS, PA, PC, PP, EVA, and rigid PVC. Furthermore, the addition of OB-1 to polyamide, nylon, and polyester systems also yields a marked improvement in whiteness.
Currently, OB-1 available on the market is primarily classified into two appearance types: yellow-phase and green-phase. The core differences between the two are reflected in the following three aspects:
Different Production Processes
Yellow-phase OB-1 and green-phase OB-1 are manufactured via esterification and sulfidation methods, respectively. Comparatively, the production cost of yellow-phase OB-1 is slightly higher than that of its green-phase counterpart.
Different Color Shade (Undertone)
This is the most intuitive distinction between the two. Yellow-phase OB-1 exhibits a bluish-violet fluorescent shade, while green-phase OB-1 shows a bluish shade. Generally, a stronger blue undertone indicates finer particle size, resulting in a whiteness that tends toward a cool white (blue-white). This cooler shade aligns more closely with current mainstream aesthetic preferences, which is why green-phase OB-1 is now more favored among manufacturers.
Actual Whitening Performance
Despite the differences in production process and color shade, there is no significant disparity in their ultimate whitening effectiveness in practical applications. Both can achieve ideal whitening levels.