Organic compounds -- part of the class 532-570 series – Organic compounds – Nitriles
Reexamination Certificate
2001-11-03
2003-06-24
McKane, Joseph K. (Department: 1626)
Organic compounds -- part of the class 532-570 series
Organic compounds
Nitriles
C568S607000
Reexamination Certificate
active
06583308
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to yellow colorants comprising a chromophore having at least one poly(oxy-C
2
-C
4
-alkylene) chain attached to an aromatic methine backbone having at least one cyanoester moiety attached thereto. The ester portion must include a C
1
-C
8
(such as ethyl, butyl, hexyl, or ethyl-hexyl) pendant group and the poly(oxyalkylene) chain must average at most 6 monomers and at least 3 monomers, with ethylene oxide as the capping group. Such a specific group of coloring agents provides the best overall yellow colorations or effects (either alone or in blends with other coloring agents, particularly at low color loadings) as well as the best overall low extraction levels when present within clear polyester (such as polyethylene terephthalate, for example), when compared to all other known polymeric yellow colorants for the same end-use. 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 and due to high color values due to low degrees of pendant group additions thereto and thus greater amounts of chromophore constituents within the colorant compound itself), high thermal stability, effective lightfastness (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 intrinsic viscosity loss 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, but not necessarily, a yellow shade to the target resin. 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 and thus any chromophore (and resultant hue or tint) may be utilized.
Previous coloring agents for such end-uses have included pigments, dyes, or dyestuffs, with each having its own drawback. For instance, such pigments, dyes, and/or dyestuffs have not been widely introduced as colorants within plastics (such as polyolefins, polyurethanes, and the like) due to such physical limitations. However, the utilization of such colorants is highly desired for a number of reasons, foremost the actual colorations available from such specific compounds.
The standard types of polymeric colorants now utilized within plastics (be they thermoplastics or thermoset types) are primarily higher molecular weight poly(oxyalkylenated) compounds, such as methines, and the like (i.e., those found within U.S. Patent U.S. Pat. No. 4,992,204, to Kluger et al.). Some of these colorants exhibit certain problems in associated with the high color loading required to obtain significant color strengths within certain thermoplastics, such as polyesters, as one important example. Such high color loadings have a detrimental impact on the intrinsic viscosity of the target polyester (such as polyethylene terephthalate) which can effectively deleteriously have a direct impact on the strength of the target plastic itself. Thus, colorants are needed that do not exhibit such problematic effects on polyesters while still permitting thorough and substantially uniform colorations throughout the target polyester (as one thermoplastic example). Other chromophores cannot be utilized (such as triphenyl methanes, and certain azos) due to their lack of sufficient thermal stability to retain colorability when exposed to processing conditions associated with thermoplastic (e.g., primarily polyester) production. Thus, there is a need to select proper chromophores to provide yellow colorations as well as proper poly(oxyalkylene) chains and monomers in order to provide proper yellow poly(oxyalkylenated) colorants for utilization within thermoplastic (again, primarily, but not solely, polyester) formulations and articles. To date, only the higher molecular weight, and thus low color strength and/or thermally unstable, poly(oxyalkylenated) colorants have been taught within the prior art. Other colorants of either like high molecular weight or non-polymeric types have also been taught but suffer from a number of drawbacks (such as toxicity, lightfastness, thermal stability, ease in handling, and the like). There is thus a desire to introduce new types of colorants that meet these required characteristics and thus exhibit needed versatility with excellent coloring ability within desired end-uses, such as, without limitation, thermoplastics and thermosets. To date, although some liquid colorants (other than less-than-reliable pigment dispersions) have been developed for such target end-uses, unfortunately, as noted above, they have also exhibited certain limitations. A new liquid yellow colorant that provides effective colorations for such myriad end-uses as noted above and that exhibits excellent colorations, lightfastness, thermal stability, mixing with other coloring agents, and low toxicity, at least, is thus highly desired. Again, to date, there have been no teachings or fair suggestions of such a highly desirable, specific potentially liquid yellow colorant within the pertinent prior art or within the colorant industry itself.
DESCRIPTION OF THE INVENTION
It has thus now been determined that the attachment to a specific cyanoester methine compound of specific poly(oxy-C
2
-C
4
-alkylene) chains averaging at least 3 monomeric units and at most 6 monomeric units provides the needed and highly desired performance requirements noted above, particularly for transparent polyester formulations and articles. It is thus an object of the invention to provide such a colorant exhibiting (at least) excellent colorations (at low color loadings and thus causing minimal effects on intrinsic viscosity), low extraction levels, thermal stability, and lightfastness within target polyester articles (although such a specific liquid yellow colorant may be introduced within any number of thermoplastic and/or thermoset systems and/or articles). Another object of this invention to provide a yellow polymeric colorant exhibiting poly(oxyalkylene) groups that is easy to process, mixes well within target plastics, and provides excellent colorations at low color loadings within the target finished articles. Yet another object of this invention is to provide excellent colorations within liquid compositions (such as inks, and the like) through the utilization of such yellow liquid cyanoester-methine-based polymeric colorants, as noted above.
It is to be understood that the term alkyl as used throughout in relation to the ester portion of the cyanoester moiety on the methine backbone is intended to encompass any straight or branched alkyl moiety, having from 2 to 8 carbon atoms total, preferably, though not necessarily, an even number of carbon atoms within that range; the term poly(oxyalkylene) or alkyleneoxy, unless more specifically defined herein, is intended to encompass either oxyethylene, oxypropylene, or oxybutylene, with oxyethylene and oxypropylene preferred. It should be well understood by the ordinarily skilled artisan within the polymeric colorant field that an exact number of oxyalkylene monomers is rather difficult to attach and thus an average number is a more appropriate manner of describing such coloran
McKane Joseph K.
Milliken & Company
Moyer Terry T.
Parks William S.
Saeed Kamal
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