Radiation imagery chemistry: process – composition – or product th – Electric or magnetic imagery – e.g. – xerography,... – Electrophoretic imaging – process – composition – or product
Patent
1984-11-16
1986-03-25
Martin, Roland E.
Radiation imagery chemistry: process, composition, or product th
Electric or magnetic imagery, e.g., xerography,...
Electrophoretic imaging, process, composition, or product
430 78, 430106, 26024586, 26024587, G03G 506
Patent
active
045783306
DESCRIPTION:
BRIEF SUMMARY
The present invention relates to hydroxyaluminumphthalocyanine colorant compounds. These compounds are useful in photoelectrophoretic imaging materials and as electrographic toner constituents.
In various imaging systems, such as photoelectrophoretic (PEP) imaging systems, photosensitive colorants are employed to provide light sensitivity, as well as faithful reproduction of the light regions to which the colorants are sensitive. In PEP systems, colorants employed are electrically photosensitive and are selected from a variety of material classes such a phthalocyanine pigments. One of these, cyan-colored hydroxyoaluminum phthalocyanine, is particularly useful for the degree of electrical photosensitivity or speed it provides. However, its coloration is not crisp, and its peak absorption at 612 nm (as determined herein) constitutes undesirable absorption in the green spectral region. Thus, when hydroxyaluminumphthalocyanine is employed in imaging applications with magenta colorants, poor color separation results.
It is an object of the present invention to provide hydroxyaluminumphthalocyanine which exhibits improved color separation. This object has been achieved with a novel crystalline form of hydroxyaluminumphthalocyanine which has an absorption peak at 621 nm as determined herein. The present hydroxyaluminumphthalocyanine, furthermore, has a peak width of no more than 100 nm at half maximum intensity at the 621-nm peak.
Among other uses such as in paints or inks, the hydroxyaluminumphthalocyanines of the present invention are electrically photosensitive and thus suited for use in photoelectrophoretic (PEP) dispersions, elements and processes associated with such dispersions. A PEP dispersion comprises a plurality of particles composed of the present hydroxyaluminumphthalocyanine dispersed in an electrically insulating, liquefiable or liquid carrier. Hydroxyaluminumphthalocyanine colorants of the present invention are also useful as toner constituents in dry or liquid electrographic developers.
The present invention provides a novel crystalline form of hydroxyaluminumphthalocyanine. In this regard, hydroxyaluminumphthalocyanine has the following structure: ##STR1##
The new crystalline form, as noted above, exhibits an absorption peak at 621 nm which represents a bathochromic shift from the 612 nm absorption peak of prior forms of hydroxyaluminumphthalocyanine. The absorption peak, moreover, is conveniently measured when the hydroxyaluminumphthalocyanine is dispersed in a reference matrix as set forth in greater detail below.
Hydroxyaluminumphthalocyanine having the above-defined spectral absorption characteristics can be prepared by treating hydroxyaluminumphthalocyanine with piperidine or certain other organic liquids at temperatures extending from room temperature (20.degree. C.) to the refluxing temperature of the solvent, or 100.degree. C., whichever is less, as shown in the following examples.
In connection with the spectral absorption of the hydroxyaluminumphthalocyanine compounds in these examples, 1 gram of the isolated hydroxyaluminumphthalocyanine was milled for 5 days in a 7 percent, by weight, solution of poly(vinyltoluene-co-lauryl methacrylate-co-lithium methacrylate-co-methacrylic acid) in Solvesso 100.TM.. One volume part of the milled solution was combined with ten volume parts of an Isopar G.TM. (an isoparaffinic hydrocarbon liquid) solution containing 40 percent, by weight, of the binder Piccotex 100.TM.(a trademark for a copolymer of .alpha.-methylstyrene and vinyltoluene from Pennsylvania Chemical Corp.) to form a dispersion.The dispersion was hand-coated on the top layer of a reflective support containing, in sequence, a polyester substrate, a polyurethane layer containing dispersed titanium dioxide, and a cellulose acetate top layer. Absorption measurements, in the reflection mode, were made of the hand-coated hydroxyaluminumphthalocyanine-containing layer. The absorption measurement performed on the present novel crystalline form of hydroxyaluminumphthalocyanine in a reference ma
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Chemical Abstracts, vol. 80, 1974 (Columbus, Ohio, U.S.) V. A. Shorin et al.: "Synthesis of aluminum phthalocyanines substituted at the metal and study of their optical and electrical characteristics", see p. 74, Abstract No. 97325x, Izv. Vyssh. Ucheb. Zaved., Khim. Khim. Tekhnol. 1973, 16(12), 1904-1908 (Russ.).
Regan Michael T.
Wright Hal E.
Eastman Kodak Company
Janci David F.
Martin Roland E.
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