Stock material or miscellaneous articles – Composite
Reexamination Certificate
2001-10-16
2003-10-21
Zacharia, Ramsey (Department: 1773)
Stock material or miscellaneous articles
Composite
C106S493000, C552S208000, C552S238000, C552S255000, C552S258000
Reexamination Certificate
active
06635350
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to red colorants comprising a chromophore having at least one poly(oxyalkylene) chain attached to the 1-position, as well as at least one poly(oxyalkylene) chain attached to either the 8-position or the 5-position of an anthraquinone backbone. Such colorants exhibit excellent thermal stability, effective colorations, excellent low extraction rates, and high lightfastness levels, particularly when incorporated within certain media and/or on the surface of certain substrates, particularly polyesters. The poly(oxyalkylene) chains also increase the solubility in different solvents or resins thereby permitting the introduction of such excellent coloring chromophores within diverse media and/or on diverse substrates as well as provides a liquid colorant which facilitates handling. Compositions and articles comprising such colorants are provided as well as methods for producing such inventive colorants.
DISCUSSION OF THE PRIOR ART
All U.S. patents cited within this specification are hereby incorporated by reference.
There continues to be a need to provide versatile colorants within various applications such that the coloring agent itself exhibits excellent colorations (particularly at low color loadings due to inherently high absorption), high thermal stability, effective lightfastness, low extraction (or drastic reduction in possibility of removal therefrom via extraction by solvents or like sources), ease in handling, ability to mix thoroughly with other coloring agents and thus to provide effective different hues and tints within or on target substrates, and acceptable toxicity levels. There has been a need to provide improved colorants meeting this criteria for certain thermoplastic media, such as polyesters, such that the colorants themselves exhibit excellent compatibility therein (for instance in terms of dispersion and the other characteristics desired for such plastics as noted above). In particular, such characteristics for polyesters are desired for colorants that impart, for example, though not necessarily, a red shade. Other hues are available as well for such a desired, high-performing polyester plastic colorant, including violet, as one example, dependent on the presence of certain coupling or modifying moieties present on the chromophore backbone itself. It is believed and, as noted above, has been determined, that such desirable polyester plastic colorations with the characteristics noted above are possible through the addition of certain pendant groups to the chromophore backbone which do not act as couplers or color modifiers [such as, for example poly(oxyalkylene) groups] and thus any chromophore (and resultant hue or tint) may be utilized with the desired anthraquinone chromophore itself.
Previous coloring agents for such end-uses have included pigments, dyes, or dyestuffs, with each having its own drawback, be it an extraction problem from the finished article, a handling problem during manufacturing due to solid dust particles, a staining problem, due to the difficulty associated with cleaning such coloring agents from manufacturing machinery after colored plastic production, and other like issues. As a result, there is a clear desire to provide easier to handle, less extractable, easy-to-clean, etc., coloring agents for introduction within thermoplastic articles to provide decorative, aesthetic, and other like effects. However, the chromophores present within such dyes, pigments, and the like, are highly desired for the hues and shades they provide within the ultimate thermoplastic articles themselves. Facilitating the introduction of such chromophores within such formulations is thus a highly desired target within the colored thermoplastic industry, whether it be in terms of handling, extraction, cleaning, or the like.
Attempts to meet this desire have included the introduction of certain standard types of polymeric colorants within plastics (be they thermoplastic-or thermoset-types). These colorants are primarily poly(oxyalkylenated) compounds, such as triphenylmethanes, methines, and the like (i.e., those found within U.S. Pat. No. 4,992,204, to Kluger et al.). Some of these colorants exhibit certain problems during incorporation into thermosets and thermoplastics. In thermoplastic compositions such as polyesters, many of these previously disclosed compositions are not stable at the polyester processing temperatures. As a result, the colorations provided by such polymeric colorants may be reduced in strength or changed in shade under such circumstances. Other types of colorants have been discussed within the prior art, such as azos and bisazos, but the specific colorations provided by such compounds are limited to certain hues and their utilization within polyesters is suspect from a number of perspectives (such as thermal stability, and the like). There is thus a desire to introduce new types of colorants comprising different types of chromophores for the purpose of providing new, effective, versatile colorants for such myriad end-uses as noted above and that exhibit excellent colorations, extraction, thermal stability, mixing with other coloring agents, and low toxicity, at least.
One approach to obtain the desired coloration has been to use difunctional dyes that possess the necessary pendant groups to allow them to be copolymerized into a thermoplastic like polyester. This approach is exemplified by U.S. Pat. No. 4,999,418 to Krutak et al. Though such a method provides effectively colored thermoplastics with good performance such as excellent extraction (due to the copolymerized nature of the dyes), good lightfastness, low toxicity, and the like, there are many drawbacks to such technology. Primarily, such drawbacks include the necessity for extremely thermally stable chromophores because the colorant must survive in the reactor for extended periods of time in addition to the heat history afforded by the molding of the finished article (e.g., such thermal stability requirements greatly limit the selection of hues and often provides for more expensive colorant molecules). Another drawback is the necessity of dedicating a high cost polyester production vessel to color due to the inherent contamination of the vessel by the colorant (which invariably limits flexibility in manufacturing of resins). Furthermore, another drawback is the necessity of the end user or article manufacturer to store large amounts of colored resins of different shades which limits the flexibility and adds cost to the end user. The colorants disclosed, for example within U.S. Pat. No. 4,499,418, are inherently powdered or like solid in nature and thus are not suitable for direct addition to the molten plastic during any injection molding step, as one example. Such powdered coloring agents are developed solely for actual polymerization within the target resin prior to any molding, injection, and other like process step. Drawbacks, thus, to these powdered types include undesirable dusting, contamination and staining of equipment, clogging (during feeding into the molten resin, for example), and poor control of metering during coloring of the target resin within and/or at the molding machinery. Other less noticeable drawbacks exist for such standard polyester coloring technology; however, these issues clearly show that improvements are highly desired to provide easily handled liquid colorants for polyester which are thermally stable and offer excellent performance in areas such as extraction.
Another approach to coloration of thermoplastics such as polyesters and namely polyethylene terephthalate has been through the use of pigments (Thomas G. Weber, Editor, Coloring of Plastics, John Wiley and Sons, New York, 1979). The use of pigments (either neat or in a liquid dispersion), however, is accompanied by undesireable properties such as opacity, dullness of color, low tinctorial strength, and the like, associated with such pigment compounds and formulations. Also, difficulties in uniformly blending the insoluble pigments with the th
Connor Daniel M.
Miley, Jr. John W.
Milliken & Company
Moyer Terry T.
Parks William S.
Zacharia Ramsey
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