Methods of producing stable novel black polyurethane...

Details Methods of producing stable novel black polyurethane... Methods of producing stable novel black polyurethane...

2003-03-31

2004-09-21

Cooney, Jr., John M. (Department: 1711)

Synthetic resins or natural rubbers -- part of the class 520 ser

Synthetic resins

Cellular products or processes of preparing a cellular...

C521S115000, C521S128000, C521S129000, C521S130000, C521S170000, C521S174000

Reexamination Certificate

active

06794420

ABSTRACT:

FIELD OF THE INVENTION
This invention relates to polyurethane article black colorants which comprise a novel blue polymeric anthraquinone colorant, rather than the previous standard polymeric triphenylmethane blue-type colorants. Such a novel blend of colorants to produce black colorations within the target polyurethane foams exhibits very low color degradation during polyurethane foam formation, primarily due to the stability and resiliency of the novel anthraquinone-based polymeric colorant in the presence of high isocyanate levels, as well as large amounts of reactive tertiary amines (from catalyst residue, for example). A black colorant comprising such a novel blue polymeric colorant, as well as polyurethane foams comprising such a novel black coloring agent and methods of producing such foams are all contemplated within this invention.
BACKGROUND OF THE PRIOR ART
This invention relates to a novel black colorant composition, which exhibits very low color degradation during the execution of polyurethane foams. The colorant composition may be incorporated into a resin.
A material will appear black if substantially all of the light in the visible electromagnetic spectrum (400-700 nanometer) is absorbed. Thus, black colorant compositions may be mixtures of two, three or more individual colorants, which compliment each other to absorb light across the spectrum. For example, orange and blue; yellow, red and blue; and orange, blue and purple represent color combinations which will create a black composition.
In general, a black colorant composition made by combining two or more colorants will absorb electromagnetic radiation across the entire visible spectrum, but the absorbance at each wavelength may not be uniform. Consequently, the absorbance of such a composition may be represented by a series of peaks and valleys across the visible spectrum. Loss or modification of any of the component results in change of hue of the black. Such color loss may be caused by any number of conditions however, it has been realized that certain blue polymeric colorants, such as certain triphenylmethane and/or anthraquinone types, that actual degradation of the compounds themselves contributes most prominently to such deleterious color shifts, particularly within foam articles.
Polymeric colorants have become the preferred coloration method in industry for polyurethane products, such as foams, resins, and the like. Being liquid in nature, these polymeric colorants contain hydroxyl terminated polyoxyalkylene chain (or chains) and actually tend to react to and within the urethane during polymerization. As a result, the color is integrated within the foam and provides excellent uniformity and depth throughout the entire article. Generally, these colorations are performed in situ during foam, resin, etc., formation. For instance, polymeric colorants (i.e., polyoxyalkylenated colorants), such as those described in U.S. Pat. No. 4,284,279 to Cross et al., have been introduced within polyol compositions during slabstock foam production. The “colored” polyol then reacts with an isocyanate composition to form the desired colored foam. Such foamed products require the presence of a catalyst or catalysts to effectuate the desired reaction between the polyol and isocyanate components. The most prevalent catalysts, due to cost in using, and disposing, are tertiary amine-based compounds, To reduce emissions of residual amine catalysts, the industry has turned to using hydroxyl-terminated type amine catalysts, most notably DMEA and DABCO TL catalysts (a blend of triethylene diamine and 2-{[2-dimethylamino)ethyl]methylamino}ethanol) and Texacot ZF10 (N,N,N′-trimethl-N′-hydroxyethyl-bis(aminoethyl)ether). These catalysts unfortunately present the ability to exaggerate certain problems within the resultant foams, most notably color loss and/or degradations. Apparently, such catalysts could react with colorants such as TPM-based chromophores as disclosed in U.S. Pat. Nos. 4,992,204 to Kluger et al., during polyurethane formation. The high temperatures associated with polyurethane foam production permits attack of the positively charged TPM polymeric colorants, such as Reactint® Blue X3LV (from Milliken Chemical). With a strong positive charge on the base carbon of such a TPM chromophore, the hydroxyls present within the catalyst are drawn to the colorant and appear to react in some fashion to weaken the necessary strong color-producing positive charge. Such deleterious weakening of the TPM color strength (through the believed degradation of the actual colorant structure itself), thus apparently causes a severe reduction in color and/or a shift of hue within the foam media. Seemingly, such high temperature discolorations and degradations more readily occur between about 15 and 60 minutes after foam generation (after gelation and blowing of the foam-producing composition) has taken place. Without the presence of environmentally unfriendly and thus avoided CFC auxiliary blowing agents, such an exothermic reaction reaches higher temperatures that exaggerate the problem and thus need alternate methods of dissipation in order to permit color retention of the previously utilized blue colorant components of the standard black colorant formulation. Due to the insulating effect of polyurehtane foams as well, these high temperatures are also retained for several hours, if not days, also permitting exaggeration of this problem. Thus, in effect the high temperatures generated in such a manner increase the rate of attack by the hydroxyl of the catalyst on the TPM constituents. As a result, discrete areas within the middle of the final article are most like discolored as compared with the remaining portions of the article.
One specific issue exists in the utilization of polymeric triphenylmethane colorants as components within black formulations, such as within Reactint® Black X77 (from Milliken Chemical), for the coloration of polyurethane foam articles (as mentioned above). Such TPM colorants, which comprise highly desirable polyoxyethylene chains, polyoxypropylene chains, or both, provide extremely effective colorations to target polyurethane media. However, as noted above, certain polymerization catalysts, which happen to be some of the desired catalysts throughout the industry, tend to attack the TPM chromophore at the positively charged carbon center and/or the nitrogen linking groups (present between the TPM backbone and the polymeric chains), thereby degrading the colorants themselves and/or changing the hue thus preventing effective colorations of the target foam article. The target black colorant formulations thus suffer greatly in terms of color retention and exhibit color loss or shade modification (e.g., loss of blue colorant components while leaving the remaining primary colorants constituting the uneffected blend which, as these are generally mixtures of red, yellow, violet, orange, etc., colorants, result in actual shade shifts away from the desired black) as a result of this problem. To solve the above-noted degradation issue, certain anthraquinone-based polymeric colorants, including those disclosed in U.S. Pat. No. 4,137,243 to Farmer, and U.S. Pat. No. 4,846,846 to Rekers et al., have been utilized as an alternative to such TPM-based types for polyurethane foam end-uses. Certain anthraquinone-based blue polymeric colorants have also been utilized as components to replace TPM blues within black formulations, such as within Reactint® Black 2256 (from Milliken Chemical). Although such anthraquinone-type polymeric colorants (such as Reactint® Blue X17, from Milliken Chemical) are less susceptible to degradation due to amine catalyst residues, these previously used polymeric anthraquinones suffer similar degradation characteristics as a result of the presence of higher levels of diisocyanate (hereinafter, “High TDI Index”, basically an amount in excess of about 15 weight percent of isocyanate within the entire polyurethane formulation) within the target polyurethane foam pre-cursor f

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