Dye diffusion image separation systems with thermal solvents

Details Dye diffusion image separation systems with thermal solvents Dye diffusion image separation systems with thermal solvents

1991-12-06

2001-08-21

Angebranndt, Martin (Department: 1756)

Radiation imagery chemistry: process, composition, or product th

Transfer procedure between image and image layer, image...

Diffusion transfer process, element, or identified image...

C430S226000, C430S223000, C430S618000, C430S632000

Reexamination Certificate

active

06277537

ABSTRACT:

TECHNICAL FIELD
This invention relates to chromogenic photographic imaging systems that utilize silver halide based rdiation sensitive layers and associated formation of image dyes. In particular, this invention relates to such systems where the resulting dye images, when the photographic elements are substantially dry, are transferred to a polymeric receiver layer, thereby separating the developed silver and dye images.
BACKGROUND ART
Thernal Solvents in Dry Phototherrnographic Systems
Heat processable photosensitive elements can be constructed so that after exposure, they can be processed in a substantially dry state by applying heat. It is known how to develop latent image in a photographic element not containing silver halide wherein organic silver salts are used as a source of silver for image formation and amplification. Such processes are described in U.S. Pat. No. 3,429,706 (Shepard et al.) and U.S. Pat. No. 3,442,682 (Fukawa et al.). Other dry processing thermographic systems are described in U.S. Pat. No. 3,152,904 (Sorenson et al.) and U.S. Pat. No. 3,457,075 (Morgan and Shely). A variety of compounds have been proposed as “carriers” or “thermal solvents” or “heat solvents” for such systems, whereby these additives serve as solvents for incorporated developing agents, or otherwise facilitate the resulting development or silver diffusion processes. Acid amides and carbamates have been proposed as such thermal solvents by Henn and Miller (U.S. Pat. No. 3,347,675) and by Yudelson (U.S. Pat. No. 3,438,776). Bojara and de Mauriac (U.S. Pat. No. 3,667,959) disclose the use of nonaqueous polar solvents containing thione, —SO
2
— and —CO— groups as thermal solvents and carriers in such photographic elements. Similarly, La Rossa (U.S. Pat. No. 4,168,980) discloses the use of imidazoline-2-thiones as processing addenda in heat developable photographic materials.
Thermal solvents for use in substantially dry color photothermographic systems have been disclosed by Komamura et al. (U.S. Pat. No. 4,770,981), Komamura (U.S. Pat. No. 4,948,698), Aomo and Nakamaura (U.S. Pat. No. 4,952,479), and Ohbayashi et al. U.S. Pat. No. 4,983,502). The terms “heat solvent” and “thermal solvent” in these disclosures refer to a non-hydrolyzable organic material which is a liquid at ambient temperature or a solid at an ambient temperature but melts together with other components at a temperature of heat treatment or below but higher than 40° C. Such solvents may also be solids at temperatures above the thermal processing temperature. Their preferred examples include compounds which can act as a solvent for the developing agent and compounds having a high dielectric constant which accelerate physical development of silver salts. Alkyl and aryl amides are disclosed as “heat solvents” by Komamura et al. (U.S. Pat. No. 4,770,981), and a variety of benzamides have been disclosed as “heat solvents” by Ohbayashi et al. (U.S. Pat. No. 4,983,502). Polyglycols, derivatives of polyethylene oxides, beeswax, monostearin, high dielectric constant compounds having an —SO
2
— or —CO— group such as acetamide, ethylcarbamate, urea, methylsulfonamide, polar substances described in U.S. Pat. No. 3,667,959, lactone of 4-hydroxybutanoic acid, methyl anisate, and related compounds are disclosed as thermal solvents in such systems. The role of thermal solvents in these systems is not clear, but it is believed that such thermal solvents promote the diffusion of reactants at the time of thermal development. Masukawa and Koshizuka disclose (U.S. Pat. No. 4,584,267) the use of similar components (such as methyl anisate) as “heat fusers” in thermally developable light-sensitive materials.
Other Heat Developable Thermal Diffision Transer Systems
Hirai et al. (U.S. Pat No. 4,590,154) disclose a heat developable color photographic light-sensitive material comprising silver halide, a hydrophilic binder, dye releasing compounds which release mobile dyes, and a sulfonamide compound. This system requires only heat to develop the latent image and to produce mobile dyes. However, the mobile dyes are affixied to an image receiving material, which must be wetted with water prior to being contacted with the heat developed donor element. The subsequent dye diffusion transfer to the receiver element is therefore of the conventional wet diffusion type.
Nakamine et al. (U.S. Pat. No. 5,107,454) disclose a heat developable photographic chromogenic system that also utilizes diffusion transfer of dyes to an image receiving (fixing) element. The dye diffusion transfer in actuality requires that the image receiving or fixing element be wetted with water prior to being affixed to the dye donor element. The resulting dye transfer, therefore, is a wet diffusion transfer of the conventional type, not dry thermal dye transfer.
Physical Organic Characterization of Thermal Solvents
Materials can be described by a variety of extrathermodynanic properties and parameters to relate their activity, according to some performance measure, to their structure. One of the best known of such classifications is the Hammett substituent constant, as described by L. P. Hammett in
Physical Organic Chemistry
(McGraw-Hill Book Company, New York, 1940) and in other organic text books, mono-graphs, and review articles. These parameters, which characterize the ability of meta and para ring-substituents to affect the electronic nature of a reaction site, were originally quantified by their effect on the pK
a
of benzoic acid. Subsequent work has extended and refined the original concept and data, but for the purposes of prediction and correlation, standard sets of such constants, &sgr;
meta
and &sgr;
para
, are widely available in the chemical literature, as for example in C. Hansch et al.,
J. Med. Chem
., 17, 1207 (1973).
Another parareter of significant utility relates to the variation in the partition coefficient of a molecule between octanol and water. This is the so-called logP parameter, for the logarithm of the partition coefficient. The corresponding substituent or fragment parameter is the Pi parameter. These parameters are described by C. Hansch and A. Leo in
Substituent Constantsfor Correlation Analysis in Chemistry and Biology
(John Wiley & Sons, New York, 1969). Calculated logP (often termed cLogP) values are calculated by fragment additivity treatments with the aid of tables of substituent Pi values, or by use of expert programs that calculate octanol/water partition coefficients based on more sophisticated treaments of measured fragment values. An example of the latter is the widely used computer program,
MedChem Software
(Release 3.54, August 1991, Medicinal Chemistry Project, Pomona College, Claremont, Calif.).
The use of these parameters allows one to make quantitative predictions of the performance of a given molecule, and in the present invention, of a given thermal solvent candidate. The Hainnett parameters are routinely sumrned, to give a net electronic effect &Sgr;, where &Sgr; is the sum of the respective substituent &sgr;
meta
and &sgr;
para
values. Substituent and fragment parameters are readily available, so that logP and &Sgr; estimates may be easily made for any prospective molecule of interest.
Problems in the Prior Art
A major problem that remains in such wet developed systems, wherein the dye images so formed are transferred by diffusion through substantially dry gelatin, is to facilitate the ease with which such dye images may be transferred by diffusion. Another problem that exists is to facilitate such diffusion without inducing the crystallization of said dyes in the gelatin binder. Similar problems of dry dye diffusion transfer exist in color photothermographic systems that rely on dry development processes.
Much of the aforementioned prior art having to do with chromogenic image formation in diffusion transfer processes actually utilize a considerable amount of water in the diffusion process. The diffusion therefore is conventional diffusion transfer, rather than the extremely highly activated diffusion of said dyes through s

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