Radiation imagery chemistry: process – composition – or product th – Radiation sensitive product – Silver compound sensitizer containing
Reexamination Certificate
2002-08-16
2003-12-02
Le, Hoa Van (Department: 1752)
Radiation imagery chemistry: process, composition, or product th
Radiation sensitive product
Silver compound sensitizer containing
C430S613000
Reexamination Certificate
active
06656676
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a silver halide color photographic light sensitive material, and in particular to a silver halide color photographic material, which is improved so that stable photographic performance can be achieved even under an environment containing a relatively high quantity of gases adversely affecting photographic materials.
BACKGROUND OF THE INVENTION
Silver halide color photographic materials (hereinafter, also denoted simply as photographic materials, after manufacture thereof are delivered not only in a light-shielding package but also in a package reducing influences of the external environment. Thus, to shield physical impact, temperature, humidity and harmful gases from the outside, photographic materials are loaded into a film cassette or cartridge, put into a resin vessel or packed with sheet material resistant to moisture or gas permeation. Further, in the case of a lens-fitted film package, a camera body is packaged with sheet material exhibiting low moisture or gas permeability.
However, after a user breaks the shield of a purchased photographic material and loads it into a camera, the user takes care for adverse physical impact, temperature and humidity by himself but cannot provide protection from harmful gases. In cases when silver halide color photographic material is stocked while loaded in a camera under an environment containing a relatively high quantity of a harmful gas over a long period of time, the harmful gas enters the camera through the opening, resulting in aging deterioration in speed or other photographic performance and making it difficult to achieve stable performance. Such changes occur markedly in exposed portions in contact with the harmful gas, depending on the enclosing state, rather than being uniformly occurring overall on the photographic material, and unnatural non-uniformity in image density is produced. It is difficult to deal with such problems by making corrections in printing, so that an improvement thereof is desired.
In years past, problems exist due to formaldehyde gas released from adhesives used in furniture and various techniques to solve such problems were disclosed and put into practice. For example, a technique for enhancing resistance to formalin gas was disclosed in JP-B No. 63-32378 and 1-32977 (hereinafter, the term, JP-B refers to Japanese Patent Publication), JP-A No. 58-10738, 61-272743, 62-54259, 63-214745, 1-237651 and 1-297642 (hereinafter, the term, JP-A refers to Japanese Patent Application Publication); JP-B No. 60-40016 disclosed a technique for enhancing formalin gas resistance by the use of a specific magenta coupler, thereby achieving markedly improved effects.
However, it was proved that recent changes of user's lifestyle have resulted in the presence of harmful gases other than the foregoing formaldehyde gas, leading to the likelihood of adversely affecting photographic performance of silver halide color photographic material.
For example, it was proved that running an oil fan heater in a well sealed room in the winter season resulted in the probability of deteriorating photographic performance of a silver halide color photographic material which was loaded in a camera placed therein. This was supposed to be due to the fact that enhanced combustion efficiency of the oil fan heater, compared to conventional oil stoves, resulted in increased release of nitrogen oxide, which was further increased by the well sealed homes. This has become obvious by popularization of oil fan heaters and change in home environments.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide an improved silver halide color photographic material so that stable photographic performance can be achieved even under an environment containing a relatively high quantity of gases adversely affecting photographic materials.
It is another object of the invention to provide a silver halide color photographic material, photographic performance of which is little affected even when stocked in a room using an oil fan heater.
The above objects of the invention can be accomplished by the following constitution:
A silver halide color photographic material comprising a support having on one side thereof photographic component layers comprising a red-sensitive layer unit, a green- sensitive layer unit, a blue-sensitive layer unit and a light-insensitive layer, wherein at least one of the photographic component layers contains an oil-soluble organic basic compound exhibiting an acid dissociation constant (pKa) of 5.5 to 8.5, and at least one of the photographic component layers contains a cationic starch.
DETAILED DESCRIPTION OF THE INVENTION
In the invention, an oil-soluble organic basic compound exhibiting a pKa value of 5.5 to 8.5 is useful to achieve the objects of the invention. As is commonly known, the pKa value refers to a logarithmic acid dissociation constant (Ka), i.e., pKa=−logKa, which is also called an acid electrolytic dissociation exponent. The pKa value of the oil-soluble basic compound can be determined by the alkalimetry, in the following manner. Thus, 50 mg pf a compound sample is dissolved in 40 ml of ethanol and after adding 10 ml of distilled water thereto, 3 ml of a 0.5 mol/l hydrochloric solution and 12 ml of ethanol are further added. The thus prepared solution is subjected to an alkalimetry at a temperature of 25° C. using an alkaline solution (which is comprised of 2.0 g of sodium hydroxide, 200 ml of distilled water and 800 ml of ethanol) and an automatic titration apparatus (Auto Titrator AUT-301, available from TOA electronics, Ltd.).
The oil-soluble basic compound relating to the invention preferably exhibits a log P value of 6 to 14, and more preferably 8 to 14. The log P value, which is also denoted as logarithm of octanol-water partition coefficient, is a parameter concerning water-solubility. The log P value can generally be determined by the octanol-water extraction method.
The oil-soluble basic compound of the invention refers to a compound, which soluble in a high boiling solvent used in silver halide color photographic materials (e.g., dioctyl phthalate, di-I-decyl phthalate, tricresyl phosphate, trioctyl phosphate, 2,4-dinonylphenol, etc.) and is capable of forming a salt with a mineral acid, such as hydrochloric acid, sulfuric acid, or nitric acid. The oil-soluble basic compound preferably exhibits a solubility of at least 1 g in 100 ml of ethyl acetate at 40° C., and it is more preferable that 1 wt % of the oil-soluble basic compound in a ethanol/water solution (=8/2 by volume ratio) at 25° C. exhibits a pH higher by at least 0.1 than a pH of a ethanol/water solution (=8/2 by volume ratio) at 25° C., and at least 5 g of the basic compound is soluble in 100 ml ethyl acetate at 40° C. It is still more preferable that the foregoing oil pH variation is at least 2 and solubility in 100 ml ethyl acetate is at least 10 g.
The oil-soluble organic basic compounds used in the invention are preferably a compound represented by the following formula (V), as described in U.S. Pat. No. 6,127,108:
wherein X represents an electron-attractive group having a Hammett's substituent constant &sgr;p value of 0.25 or more; Y represents an alkylene group in which the carbon number of the main chain is 1 through 3; Z represents a non-metallic atom group necessary for forming a 5- to 7-membered non-aromatic heterocycle together with a nitrogen atom as shown in formula (V), and wherein when Z contains a second nitrogen atom and there is no nitrogen atom in Z more than two, the compound includes a substituent (—Y′—X′) which is attached to the second nitrogen, in which X′ is the same as defined in X and Y′ is the same as defined in Y, X and X′ or Y and Y′ may be the same or different, provided that there is no basic amino group other than a basic skeleton of a non-aromatic heterocycle represented by
and the number of the carbon atoms in the molecule is 14 or more.
In the formula (V), the electro
Iwagaki Masaru
Nomiya Makoto
Konica Corporation
Le Hoa Van
Muserlian, Lucas and Mercanti LLP
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