Radiation imagery chemistry: process – composition – or product th – Radiation sensitive product – Silver compound sensitizer containing
Reexamination Certificate
2001-10-24
2003-07-08
Le, Hoa Van (Department: 1752)
Radiation imagery chemistry: process, composition, or product th
Radiation sensitive product
Silver compound sensitizer containing
Reexamination Certificate
active
06589724
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to a color photographic element comprising, in a layer containing a light-sensitive silver halide emulsion layer or in a non-silver containing light-insensitive layer, a speed-improving benzotriazole polymer with a certain minimum degree of hydrophobicity.
BACKGROUND OF THE INVENTION
It is a long-standing objective of color photographic origination materials to maximize the overall response to light while maintaining the lowest possible granularity. Increased photographic sensitivity to light (commonly referred to as photographic speed) allows for improved images captured under low light conditions or improved details in the shadowed regions of the image. In general, the overall light sensitivity provided by the light-sensitive silver halide emulsions in such systems is determined by the size of the emulsion grains. Larger emulsion grains capture more light. Upon development, the captured light is ultimately converted into dye deposits which constitute the reproduced image. However, the granularity exhibited by these dye deposits is directly proportional to the grain size of the silver halide emulsion. Thus, larger silver halide emulsion grains have higher sensitivity to light but also lead to higher granularity in the reproduced image. Therefore, it is a fundamental problem in photography to improve the light sensitivity of a silver halide element without a corresponding increase in another property such as granularity. In this description, it will be understood that the demonstrated increase in sensitivity is accomplished without a significant sacrifice in granularity. Stated from another perspective, it has been a long-standing problem to provide materials which maximize the response to light of a silver halide emulsion for any given grain size.
For example, it is well known that highly reactive couplers or couplers that form dyes with high extinction coefficients can maximize the response of silver halide emulsions. However, the increased amplification caused by these types of dye forming materials also directly leads to higher granularity.
It is highly desirable to provide non-imaging materials that lead to increased photographic speed without having to increase the size of the light-sensitive silver halide grains. Ideally, the addition of such materials should not require the use of permanent solvents (non-reactive, non-volatile organic liquids with low aqueous solubility) in order to be introduced or effective in a photographic film. The use of such permanent solvents is generally unfavorable because of cost, film thickness, increased total organic load and environmental factors.
U.S. Pat. No. 4,528,264 describes the use of polymeric benzotriazoles as antifoggants. However, the materials disclosed do not provide improved light sensitivity.
Pending application U.S. Ser. No. 09/358,057 (D78393) describes the use of certain polymeric heterocycles derived from a monomeric heterocycle, including benzotriazoles, with a ClogP of 6.2 or greater to increase the light sensitivity of a photographic element.
Pending application Ser. No. 09/540,808 (D80060) describes the use of certain polymeric heterocycles derived from either bicyclic monomers with a minimum of 3 heteroatoms of which no more than 2 heteroatoms can be connected in sequence and a ClogP less than 6.2 or monocyclic monomers with 3 heteroatoms and a ClogP of less than 8.75 to increase the light sensitivity of a photographic element.
U.S. Pat. Nos. 5,213,959 and 5,275,931 describe the use of heterocyclic antifoggants that have a reactive substituent that chemically reacts with the dispersing medium to form a covalent bond in a photographic element to prevent diffusion.
A problem to be solved is to provide color photographic elements that exhibit improved photographic speed and methods for processing such elements. In particular it is desirable to provide improved speed using polymeric benzotriazoles useful over a broader range of Calculated logP values than heretofore available.
SUMMARY OF THE INVENTION
The invention provides a color silver halide photographic element comprising a light-sensitive silver halide emulsion layer or a non-silver containing light-insensitive layer, said light-sensitive or light-insensitive layer containing a polymer compound comprising a repeating benzotriazole subunit wherein
a) the benzotriazole monomer corresponding to the benzotriazole subunit has a Calculated logP of at least 3.1 and less than 6.2; or
b) the benzotriazole monomer corresponding to the benzotriazole subunit has a Calculated logP of less than 3.1 and the polymer additionally comprises a co-monomer with Calculated logP of 0.5 or greater;
and the amount of the polymer compound in the element is sufficient to increase the photographic speed of the element compared to the same element without the polymer compound.
The invention provides color photographic elements that exhibit improved photographic speed and methods for processing such elements.
DETAILED DESCRIPTION OF THE INVENTION
The invention is generally as described above. In various aspects of the invention, the imaging layer that contains the polymer comprises an iodobromide emulsion, comprises a particular grain size, is an origination material, and is processed with a color developer such as a paraphenylene diamine developer. In other aspects of the invention, the polymer is located in a layer adjacent to an imaging layer.
The present invention relates to a light-sensitive color photographic element with at least one red sensitive silver halide emulsion layer with at least one non-diffusing cyan coupler, at least one green sensitive silver halide emulsion layer with at least one non-diffusing magenta coupler and at least one blue sensitive silver halide emulsion layer with at least one non-diffusing yellow coupler.
The feature of the polymeric materials of the invention that enables the desired increase in light sensitivity is a balance in the overall degree of hydrophobicity or water solubility. This can be achieved in two ways. The first to increase the hydrophobicity of the benzotriazole subunit by using the appropriate substituents such that the Calculated logP (as defined hereinafter) of the corresponding monomer is at least 3.1 but less than 6.2. Whenever the Calculated logP of the benzotriazole unit is at least 3.1 , it is preferred that there is an additional co-monomer (not restricted to any particular range of Calculated logP) that contains an ionizable water-solubilizing group (hereinafter referred to as the ionizable monomer or IM) in order to achieve the best balance of overall hydrophobicity. If the Calculated logP of the benzotriazole monomer is less than 3.1, then it is also possible to increase the hydrophobicity of the polymer by the addition of a co-monomer that has a Calculated logP of at least 0.5 or greater (hereinafter referred to as high Calculated logP co-monomer or CM). It is also preferred that either the CM used with benzotriazoles with Calculated logP of less than 3.1 has an ionizable water solubilizing group or that a IM is additionally present.
It is desired that the compound of the invention should achieve an improvement in terms of photographic speed, compared to the same element without the compound, of at least 0.05, and desirably at least 0.10 and even 0.25 stops or more without causing a significant increase in granularity.
The polymeric materials of the invention, or “speed polymers,” are polymers that contain a repeating benzotriazole unit. The polymeric backbone may be all carbon atoms (such as those derived from polymerization of olefinic materials) or may contain heteroatoms including nitrogen or oxygen atoms (such as polyesters, polyethers, polyureas, polycarbonates or polyamides produced by condensation or ring opening reactions, etc.). Preferred units are defined by the following general formula (A), whose corresponding monomer, defined by the following general formula (A′) meets the Calculated logP requirements:
where R is hydrogen, cyano, carbonyl, alkyl or aryl group,
Allway Philip A.
Bailey David B.
Clark Bernard A.
Friedrich Louis E.
Ross David S.
Eastman Kodak Company
Kluegel Arthur E.
Le Hoa Van
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