| abstract |
Thermoplastic, non-water soluble, fluorescent pigments having improved lightfastness are provided which are suitable for coloring a variety of materials including plastics, particularly polyolefins, as well as paints, inks and textiles. The pigments of the present invention referred to herein as the "light fast pigments" demonstrate good color, migration resistance, heat stability, water insolubility, friability and resistance to plateout. The light fast pigments of the present invention have several embodiments, the polyamide embodiment, polyamide ester embodiment and the polyester embodiment. The pigments of the present invention comprises a polymer which comprises polymerized units of fluorescent dye and polymerized monomers such as for example dicarboxylicacids, polycarboxylicacids, diamines, polyamines, alkanolamines, carboxyalcohols, carboxyamines and difunctional alcohols, and/or polyhydric alcohols. The polyamide pigment embodiment and polyamide-ester pigment embodiment are polymers which comprise polyamide linkages. The polyester pigment embodiment are polymers that comprise polyester linkages, but substantially lacks polyamide linkages. The light fast pigments of the present invention contain a fluorescent dye reacted into, and covalently bound to the polymer backbone; this distinguishes the light fast pigment from conventional pigments which typically exist as a solid state solution of fluorescent dye and polymer carrier. In the polyester pigment embodiment, the fluorescent dye, which is physically incorporated into the backbone of polymer chain, is the BXDA fluorescent dye or an analog thereof. In the polyamide pigment and polyamide-ester pigment embodiments, the fluorescent dye is the BXDA fluorescent dye or its analogs thereof, or certain conventional dyes. While the light fast pigment of the present invention demonstrate improved lightfastness, the addition of an optional light stabilizer enhances the lightfastness of the pigment. The invention also relates to a method of making such light fast pigment. |