Photothermographic accelerators for leuco diazine, oxazine, and thiazine dyes
AssigneeMinnesota Mining and Manufacturing Company
InventorsPeter A. Bellus, Robert A. Frenchik
Life of this patent
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Abstract
A photothermographic construction comprises a light-sensitive color-forming element on a support base, the element comprising a silver source, optionally silver halide, a binder, and an oxidizable leuco phenazine, phenoxazine, or phenothiazine dye, and as development accelerator a carboxylic acid, Lewis acid, or Bronsted acid.
Claims16
A single-sheet, negative-acting photothermographic construction comprising at least one light-sensitive color-forming element on a support base, the element comprising a light-sensitive and a non light-sensitive silver source, a binder, an oxidizable leuco phenazine, phenoxazine, or phenothiazine dye as the sole reducing agent for said silver sources, present as 0.1 to 10 percent by weight of the imaging layer, or 2 or 15 weight percent if the reducing agent is in the second layer of a two-layer construction, in an amount sufficient to provide color, and as development accelerator a carboxylic acid, a Lewis acid selected from the group consisting of halide, nitrate, sulfate, sulfonate, and carboxylate salts, or a Bronsted acid selected from the group consisting of sulfonic and sulfinic acids, phenols, phosphonic and phosphinic acids, and sulfimides;
- wherein the image color is provided by the oxidized form of said leuco dye.
A single-sheet, negative-acting photothermographic construction comprising at least one light-sensitive color-forming element on a support base, said element comprising a silver source, silver halide, a leuco dye as the sole reducing agent for said silver source and silver halide present as 0.1 to 10 percent by weight of the imaging layer, or 2 to 15 weight percent if the reducing agent is in the second layer of a two-layer construction, in an amount sufficient to provide color, a binder, and a development accelerator,
- (a) said leuco dye comprising a phenazine, phenotiazine, or phenoxazine leuco dye having the formula ##STR38## wherein each R is the same or different and is independently selected from
- (1) hydrogen,
- (2) an unsubstituted aryl or alkyl group or these groups substituted by up to four groups selected from alkyl, alkoxy, cyano, hydroxy, [halogen,] alkylsulfonyl, arylsulfonyl, a halogen atom, and Z where Z is as defined below, wherein all alkyl and alkoxy groups have 1 to 20 carbon atoms, and
- (3) Z, wherein Z is ##STR39## wherein each Q is the same or different and is independently selected from (1) hydrogen,
- (2) an unsubstituted aryl or alkyl group or these groups substituted by up to four groups selected from alkyl, alkoxy, cyano, hydroxy, alkylsulfonyl, arylsulfonyl, a halogen atom, and Z, where Z is as defined above, and wherein all alkyl and alkoxy groups have 1 to 20 carbon atoms;
- R' is the same or different and is independently selected from hydrogen, halogen, or an alkyl or alkoxy group of 1 to 6 carbon atoms or these groups substituted by up to 3 halogen atoms;
- and
- X is --S--, --O--, or --NQ--;
- L is hydrogen or Z;
- with the proviso that R and L can have up to a total of 5 carbonyl and sulfonyl groups;
- and
- (b) said development accelerator comprising at least one of
- (1) a carboxylic acid having the formula
- R.sup.10 (COOH).sub.n
- wherein
- n is an integer having the value 1 to 4,
- R.sup.10 is a group which is unsubstituted or substituted by at least one group selected from amino, hydroxyl, aryl, lower alkyl, lower alkoxy, cyano, sulfonyl, mercapto, nitro, a halogen atom, and Z, wherein Z is as defined above,
- wherein
- when n is 1,
- R.sup.10 is selected from the group consisting of alkyl, alkenyl, aryl, and phenylalkyl groups having up to 10 carbon atoms, and
- when n is 2, 3, or 4,
- R.sup.10 is selected from the group consisting of alkenylene, alkylene, and arylene groups having up to 14 carbon atoms;
- (2) a Lewis acid selected from the group consisting of halide, nitrate, sulfate, sulfonate, and carboxylate salts;
- and
- (3) a Bronsted acid selected from the group consisting of sulfonic and sulfinic acids, phenols, phosphonic and phosphinic acids, and sulfimides;
- wherein the image color is provided by the oxidized form of said leuco dye.
A single-sheet, negative-acting, photothermographic construction comprising at least one light-sensitive color-forming element on a support base, the element comprising a light-sensitive and a non light-sensitive silver source, a binder, a reducing agent consisting of an oxidizable leuco phenazine, phenoxazine, or phenothiazine dye present as 0.1 to 10 percent by weight of the imaging layer, or 2 to 15 weight percent if the reducing agent is in the second layer of a two-layer construction, in an amount sufficient to provide color, and as development accelerator a carboxylic acid, a Lewis acid selected from the group consisting of halide, nitrate, sulfate, sulfonate, and carboxylate salts, or a Bronsted acid selected from the group consisting of sulfonic and sulfinic acids, phenols, phosphonic and phosphinic acids, and sulfimides;
- wherein the image color is provided by the oxidized form of said leuco dye.
A single-sheet, negative-acting photothermographic construction comprising at least one light-sensitive color-forming element on a support base, said element comprising a silver source, silver halide, a reducing agent for said silver source and silver halide consisting of an oxidizable leuco dye present as 0.1 to 10 percent by weight of the imaging layer, or 2 to 15 weight percent if the reducing agent is in the second layer of a two-layer construction, in an amount sufficient to provide color, a binder, and a development accelerator,
- (a) said leuco dye comprising a phenazine, phenothiazine, or phenoxazine leuco dye having the formula ##STR41## wherein each R is the same or different and is independently selected from
- (1) hydrogen,
- (2) an unsubstituted aryl or alkyl group or these groups substituted by up to four groups selected from alkyl, alkoxy, cyano, hydroxy, alkylsulfonyl, arylsulfonyl, a halogen atom, and Z where Z is as defined below, wherein all alkyl and alkoxy groups have 1 to 20 carbon atoms, and
- (3) Z, wherein Z is ##STR42## wherein each Q is the same or different and is independently selected from (1) hydrogen,
- (2) an unsubstituted aryl or alkyl group or these groups substituted by up to four groups selected from alkyl, alkoxy, cyano, hydroxy, alkylsulfonyl, a halogen atom, arylsulfonyl and Z, where Z is as defined above, and wherein all alkyl and alkoxy groups have 1 to 20 carbon atoms;
- R' is the same or different and is independently selected from hydrogen, halogen, or an alkyl or alkoxy group of 1 to 6 carbon atoms or these groups substituted by up to 3 halogen atoms;
- and
- X is --S--, --O--, or --NQ--;
- L is hydrogen or Z;
- with the proviso that R and L can have up to a total of 5 carbonyl and sulfonyl groups;
- and
- (b) said development accelerator comprising at least one of
- (1) a carboxylic acid having the formula
- R.sup.10 (COOH).sub.n
- wherein
- n is an integer having the value 1 to 4,
- R.sup.10 is a group which is unsubstituted or substituted by at least one group selected from amino, hydroxyl, aryl, lower alkyl, lower alkoxy, cyano, sulfonyl, mercapto, nitro, a halogen atom, and Z, wherein Z is as defined above,
- wherein
- when n is 1,
- R.sup.10 is selected from the group consisting of alkyl, alkenyl, aryl, and phenylalkyl groups having up to 10 carbon atoms, and
- when n is 2, 3, or 4,
- R.sup.10 is selected from the group consisting of alkenylene, alkylene, and arylene groups having up to 14 carbon atoms;
- (2) a Lewis acid selected from the group consisting of halide, nitrate, sulfate, sulfonate, and carboxylate salts;
- and
- (3) a Bronsted acid selected from the group consisting of sulfonic and sulfinic acids, phenols, phosphonic and phosphinic acids, and sulfimides;
- wherein the image color is provided by the oxidized form of said leuco dye.
Dependencies are inferred from the claim text.