Golf balls generally comprise a core surrounded by a cover and optionally intermediate layers there between. The cover forms a spherical outer surface and typically includes a plurality of dimples. The core and/or the cover may incorporate multiple layers and the core may be solid or have a fluid-filled center surrounded by windings and/or molded material. Golf ball covers may be formed from a variety of materials such as balata, polyurethane, polyurea, and/or thermoplastic compositions such as ionomer resins including SURLYN® and IOTEK®, depending upon the desired performance characteristics of the golf ball and desired properties of the cover.
While conventional golf balls are white, some golfers enjoy distinguishing themselves on the course by playing a golf ball having a unique visual appearance. Accordingly, golf ball manufacturers have incorporated coloring agents such as pigments, dyes, tints, inks and the like in golf ball materials and/or coatings.
Such color agents typically contain chromophores. A chromophore is the group of atoms within a molecule that is responsible for the molecule's color. Specifically, bonds between the atoms allow the atoms to absorb some visible light while reflecting other visible light, with the reflected wavelengths of light attributing a certain apparent color to the molecule.
A notable drawback with chromosphore-based coloring agents, however, is that the apparent color fades/discolors from exposure to sunlight due to photodegradation. This occurs because the atoms in a chromophore will also absorb damaging photons within the wavelengths found in sunlight (i.e., infrared radiation, visible light, and ultraviolet light), which break down the aforementioned bonds between atoms, thereby changing the atomic configuration within each chromophore. While stabilizer packages are often used to improve light stability, such improvement can be temporary. And stabilizer packages have been known to actually contribute to discoloration as well.
Accordingly, there remains a need for golf balls having an apparent surface color that is not subject to fading or discoloration when exposed to sun light. The present invention addresses and solves this need.