US4001025A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process of sensitizing silver halide emulsions with heterocyclic sulfur compounds
Assignee: 3M Co
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Filing: 1974-10-10
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Granted: 1977-01-04
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Expires: 1994-10-10
Abstract
Abstract Silver halide crystals in photographic emulsions are sensitized by the addition of compounds to the emulsion which will form silver sulphide with the silver halide crystals at a fast reaction rate v, where v = k. [concentration of the sensitizer compound in the emulsion] and k, the rate constant for the sulphide formation under the digestion conditions is in the range of from 0.1 to 100 min - 1 , and preferably at 0.5 to 10 min - 1 , provided that the sensitizer compound will distribute itself over the silver halide crystal surfaces at a rate which is fast as compared with the reaction rate of the sensitizer compound with the silver halide crystals so that substantially every silver halide crystal has an amount of sensitizer compound adsorbed to its surface from the beginning of the reaction sufficient to give the emulsion good contrast but not sufficient to cause fog.
Inventors
- 👤 Derek J. Cash
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 19:17
CPC Classifications
G; G03; G03C; G03C1/00; G03C1/005; G03C1/06; G03C1/08; G03C1/09
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
157 words
A process for sensitizing a photographic silver halide emulsion comprises digesting the silver halide emulsion in contact with a sensitizing amount of a sensitiser whereby said sensitiser compound forms on the silver halide crystals the silver sulphide at a reaction rate v, where v = k.sup.. and k, the rate constant for the sulphide formation under the digestion conditions, is in the range of from 0.1 to 100 min - 1 , the sensitiser compound being capable of distributing itself over the silver halide crystal surfaces at a rate which is fast as compared with the reaction rate of the sensitiser compound and the silver halide crystals, in which the sensitiser compound is a compound which includes as part of a 5-, or 6-membered heterscyclic ring the grouping: ##STR9## in which R 2 and R 3 represents a hydrogen atom or an alkyl, alkylene, aryl, aralkyl or alkaryl group, and X represents an oxygen or sulphur atom.
Claim 2
Dependent Claim
157 words
A process for sensitizing a photographic silver halide emulsion comprises digesting the silver halide emulsion in contact with a sensitizing amount of a sensitiser whereby said sensitiser compound forms on the silver halide crystals the silver sulphide at a reaction rate v, where v = k.sup.. and k, the rate constant for the sulphide formation under the digestion conditions, is in the range of from 0.1 to 100 min - 1 , the sensitiser compound being capable of distributing itself over the silver halide crystal surfaces at a rate which is fast as compared with the reaction rate of the sensitiser compound and the silver halide crystals, in which the sensitiser compound is a compound which includes as part of a 5-, or 6-membered heterscyclic ring the grouping: ##STR9## in which R 2 and R 3 represents a hydrogen atom or an alkyl, alkylene, aryl, aralkyl or alkaryl group, and X represents an oxygen or sulphur atom.
Claim 3
Dependent Claim
19 words
A process as claimed in claim 1 in which k is from 0.5 to 10 min - 1 .
Claim 4
Dependent Claim
37 words
A process as claimed in claim 1 in which the digestion is effected at a pAg of from 6 to 9, a pH of from 5.5 to 8, and a temperature of from 25° to 80° C.
Claim 5
Dependent Claim
31 words
A process as claimed in claim 3 in which the digestion is effected at a pAg of about 8.5, a pH of about 6.5 and a temperature of about 60° C.
Claim 6
Dependent Claim
104 words
A process as claimed in claim 1 in which the sensitiser compound is one having the general formula: ##STR10## in which R 1 and R 2 , which may be the same as one another or different from one another, each represents a hydrogen atom, or an alkyl, alkylene, aryl, aralkyl or alkaryl group, or R 1 and R 2 together represent the atoms required to complete with the atoms to which they are linked an alicyclic, aromatic or heterocyclic ring, and R 3 represents a hydrogen atom or an alkyl, alkylene, aryl, aralkyl or alkaryl group, or a tautomer of such a compound.
Claim 7
Dependent Claim
109 words
A process as claimed in claim 1 in which the sensitiser compound is one having the general formula: ##STR11## in which R, R 1 and R 2 , which may be the same as one another or different from one another, each represents a hydrogen atom, or an alkyl, alkylene, aryl, aralkyl or alkaryl group, or any two of R, R 1 and R 2 together represent the atoms required to complete with the atoms to which they are linked an alicyclic, aromatic or heterocyclic ring, and R 3 represents a hydrogen atom or an alkyl, alkylene, aryl, aralkyl or alkaryl group, or a tautomer of such a compound.
Claim 8
Dependent Claim
104 words
A process as claimed in claim 1 in which the sensitizer compound is one having the general formula: ##STR12## in which R 1 and R 2 , which may be the same as one another or different from one another, each represents a hydrogen atom, or an alkyl, alkylene, aryl, aralkyl or alkaryl group, or R 1 and R 2 together represent the atoms required to complete with the atoms to which they are linked an alicyclic, aromatic or heterocyclic ring, and R 3 represents a hydrogen atom or an alkyl, alkylene, aryl, aralkyl or alkaryl group, or a tautomer of such a compound.
Claim 9
Dependent Claim
108 words
A process as claimed in claim 1 in which the sensitiser compound is one having the general formula: ##STR13## in which R, R 1 and R 2 , which may be the same as one another or different from one another, each represents a hydrogen atom, or an alkyl, alkylene, aralkyl or alkaryl group, or any two of R, R 1 and R 2 together represent the atoms required to complete with the atoms to which they are linked an alicyclic, aromatic or heterocyclic ring, and R 3 represents a hydrogen atom or an alkyl, alkylene, aryl, aralkyl or alkaryl group, or a tautomer of such a compound.
Claim 10
Dependent Claim
14 words
A process as claimed in claim 1 in which the sensitiser compound is 1-methyl-2-thiosuccinimide.
Claim 11
Dependent Claim
14 words
A process as claimed in claim 1 in which the sensitiser compound is 2-thiosuccinimide.
Claim 12
Dependent Claim
14 words
A process as claimed in claim 1 in which the sensitiser compound is thiophthalimide.
Claim 13
Dependent Claim
14 words
A process as claimed in claim 1 in which the sensitiser compound is 1-phenyl-2-thiosuccinimide.
Claim 14
Dependent Claim
14 words
A process as claimed in claim 1 in which the sensitiser compound is 1-p-anisyl-2-thiosuccinimide.
Claim 15
Dependent Claim
33 words
A process as claimed in claim 1 in which the sensitiser compound is added to the emulsion in an amount of from 0.5 to 50 micromoles per mole of silver in the emulsion.
Claim 16
Dependent Claim
182 words
A process for sensitizing a photographic silver halide emulsion comprises digesting the silver halide emulsion in contact with a sensitizing amount of a sensitiser whereby said sensitiser compound forms on the silver halide crystals the silver sulphide at a reaction rate v, where v = k.sup.. and k, the rate constant for the sulphide formation under digestion conditions of pAg 6 to 9, pH of 5.5 to 8 and temperature of 25 to 80° C, is in the range of from 0.1 to 100 min - 1 , the sensitiser compound being capable of distributing itself over the silver halide crystal surfaces at a rate which is fast as compared with the reaction rate of the sensitiser compound and the silver halide crystals in which said sensitiser compound has as part of a 5- or 6-membered heterocyclic ring the grouping: ##STR14## in which R 2 and R 3 represents a hydrogen atom or an alkyl, alkylene, aryl, aralkyl or alkaryl group, and X represents an oxygen or sulphur atom, the heterocyclic ring being neither conjugated nor capable of forming an aromatic tautomer.
Claim 17
Dependent Claim
182 words
A process for sensitizing a photographic silver halide emulsion comprises digesting the silver halide emulsion in contact with a sensitizing amount of a sensitiser whereby said sensitiser compound forms on the silver halide crystals the silver sulphide at a reaction rate v, where v = k.sup.. and k, the rate constant for the sulphide formation under digestion conditions of pAg 6 to 9, pH of 5.5 to 8 and temperature of 25 to 80° C, is in the range of from 0.1 to 100 min - 1 , the sensitiser compound being capable of distributing itself over the silver halide crystal surfaces at a rate which is fast as compared with the reaction rate of the sensitiser compound and the silver halide crystals in which said sensitiser compound has as part of a 5- or 6-membered heterocyclic ring the grouping: ##STR14## in which R 2 and R 3 represents a hydrogen atom or an alkyl, alkylene, aryl, aralkyl or alkaryl group, and X represents an oxygen or sulphur atom, the heterocyclic ring being neither conjugated nor capable of forming an aromatic tautomer.
Claim 18
Dependent Claim
11 words
The silver halide emulsion resulting from the process of claim 1.
Claim 19
Dependent Claim
11 words
The silver halide emulsion resulting from the process of claim 15.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1980-01-04 | 1980-07-05 | 1981-01-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-01-04 | 1984-07-05 | 1985-01-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-01-04 | 1988-07-05 | 1989-01-04 | $7700.00 | Window Closed / Lapsed |