Thermally developable materials with improved backside layers

A photothermographic material that comprises a support having on one side thereof, one or more thermally developable imaging layers comprising a binder and in reactive association, a photosensitive silver halide, a non-photosensitive source of reducible silver ions, and a reducing agent composition for said non-photosensitive source reducible silver ions, and

• having disposed on the backside of said support, a simultaneously coated first layer and a non-imaging backside conductive layer:
• a) said first layer comprising a film-forming polymer, and a smectite clay modified with a quaternary ammonium compound,
• b) interposed between said support and said first layer and directly adhering said first layer to said support, said non-imaging backside conductive layer comprising a mixture of two or more polymers that include a first polymer serving to promote adhesion of said backside conductive layer directly to said support, and a second polymer that is different than and forms a single phase mixture with said first polymer, wherein:
• 1) said backside conductive layer has a water electrode resistivity measured at 21.1° C. and 50% relative humidity of 1×1012 ohms/sq or less,
• 2) the total amount of mixture of two or more polymers in said backside conductive layer is at least 20 weight %,
• 3) said backside conductive layer comprises a conductive metal oxide or conductive polymer,
• 4) said film-forming polymer of said first layer and said second polymer of said backside conductive layer are the same or different polyvinyl acetal resins, polyester resins, cellulosic polymers, maleic anhydride-ester copolymers, or vinyl polymers,
• 5) said modified smectite clay is present in an amount of from about 0.5 to about 5 weight % of said dried first layer, and
• 6) said first layer has a dry thickness of from about 1 to about 7 μm.

A black-and-white photothermographic material that comprises a transparent polymeric support having on one side thereof one or more thermally developable imaging layers comprising predominantly one or more hydrophobic binders, and in reactive association, preformed photosensitive silver bromide or silver iodobromide present as tabular and/or cubic grains, a non-photo-sensitive source of reducible silver ions that includes silver behenate, a reducing agent composition for said non-photosensitive source reducible silver ions comprising a hindered phenol, and a protective layer disposed over said one or more thermally developable imaging layers, and

• having disposed on the backside of said support, a simultaneously coated backside protective layer and a non-imaging backside conductive layer:
• a) said backside protective layer comprising a film-forming polymer that is cellulose acetate butyrate, an antihalation composition, and a montmorillonite clay modified with a hydrogenated tallow ammonium compound,
• b) interposed between said support and said backside protective layer and directly adhering said backside protective layer to said support, said non-imaging backside conductive layer comprising non-acicular metal antimonate in a mixture of two or more polymers that include a first polymer serving to promote adhesion of said conductive layer directly to said support, and a second polymer that is different than and forms a single phase mixture with said first polymer,
• wherein said first polymer of said backside conductive layer is a polyester and said second polymer of said backside conductive layer is polyvinyl butyral or cellulose acetate butyrate, and said modified montmorillonite clay is present in an amount of from about 1 to about 3 weight % of the total dry binder weight of said first layer, and said first layer has a dry thickness of from about 2 to about 5 μm, and
• wherein said non-acicular metal antimonate clusters are composed of zinc antimonate (ZnSb2O6) that is present at a coverage of from about 0.1 to about 0.3 g/m2, the dry thickness of said backside conductive layer is from about 0.1 to about 0.2 μm, the weight % of said polymer mixture in said backside conductive layer is from about 25 to about 35 weight %, and said backside conductive layer has a water electrode resistivity measured at 21.1° C. and 50% relative humidity of less than about 1×1011 ohms/sq, and
• said montmorillonite clay is modified with an ammonium compound having one of the following Structures HTA-1 through HTA-5,
• wherein HT represents hydrogenated tallow and T represents Tallow.

A method of preparing a thermally developable material that comprises a support having on one side thereof, one or more thermally developable imaging layers comprising a binder and in reactive association, a non-photosensitive source of reducible silver ions, and a reducing agent composition for said non-photosensitive source reducible silver ions, comprising:

• simultaneously coating on the backside of said support and out of the same or different organic solvents, both a non-imaging backside conductive formulation comprising a conductive metal oxide in one or more binder polymers, and a first layer formulation comprising a smectite clay modified with a quaternary ammonium compound, to provide first layer over a non-imaging backside conductive layer,
• 1) said backside conductive layer, when dried, having a water electrode resistivity measured at 21.1° C. and 50% relative humidity of 1×1012 ohms/sq or less,
• 2) the total dry amount of said one or more binder polymers in said backside conductive layer is at least 20 weight %, and
• 3) said conductive metal oxide is present in an amount of less than 1 g/m2,
• 4) said modified smectite clay is present in an amount of from about 0.5 to about 5 weight % of the total dry binder weight in said first layer, and
• 5) said first layer has a dry thickness of from about 1 to about 7 μm.