JPH0667336A - Photographic emulsion containing scanvenger for geratin curing agent - Google Patents

Abstract

PURPOSE: To prevent occurrence of a reaction between the hardener diffused into dispersed grains and a coupler liable to exert adverse effects on physical and photosensitive characteristics, such as hardening and color forming performances and staining of the photographic element. CONSTITUTION: This hardened silver halide emulsion comprises a negatively charged hydrophobic coupler grains in a dispersion containing a hydrophobic hardener scavenger.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a method for hardening gelatin, especially a silver halide photographic emulsion for color. Furthermore,
It relates to a hardened silver halide photographic emulsion.

[0002]

Many color photographic emulsions comprise gelatin in which are dispersed hydrophobic additives such as couplers. Usually the couplers are dispersed in high boiling droplets and the hydrophobic solvent, coupler droplets and solvent are stabilized (prevent aggregation) by using anionic surfactants. The anionic surfactant is present on the surface of the dispersed particles and is negatively charged, resulting in hydrophobic dispersion particles. Such emulsions are often hardened with a gelatin crosslinking agent to impart various desirable physical properties to the emulsion, such as increased melting point, decreased swelling, and increased physical toughness in aqueous processing solutions. To be done.

When the hardener is a relatively hydrophobic molecule,
A significant portion of the hardener partitions into the hydrophobic droplets that contain the coupler with which the hardener may react with the coupler.
If the hardener is positively charged, it may initially be attracted to the negatively charged droplets containing the coupler. When the hardener diffused into the dispersion particles reacts with the coupler, the reaction destroys both the hardener and the coupler. This can lead to deleterious physical and photosensitivity properties such as reduced cure performance and color forming ability. In some cases, the curing agent is capable of reacting with a coupler that gives a color product,
This product can cause stains on the photographic element. Therefore, it is desirable to prevent reaction of the curing agent with the coupler.

US Pat. No. 4,904,579 discloses certain divalent 5-pyrazolone magenta couplers which improve color-forming properties and increase the photosensitivity and stability of photographic light-sensitive materials. It describes the use of certain non-color forming, dispersion resistant carboxylic acid compounds having. These carboxylic acid compounds are not used as hardener scavengers.

There are several alternative methods of preventing the reaction between the coupler and the curing agent contained in the hydrophobic dispersion.
U.S. Pat. No. 4,618,573 provides that the reaction between the curing agent and the coupler can be prevented by the use of pyrazolone type magenta couplers. US Patent No. 4,8
63,841 states that the reaction between the curing agent and the coupler can be prevented by the use of divalent 5-pyrazolone type magenta couplers as opposed to tetravalent 5-pyrazolone type magenta couplers. . U.S. Pat. No. 4,877,724 discloses the use of a dication ether curing agent in which one or more of the dication ethers is an anion such that the reaction between the curing agent and the coupler produces an intramolecular salt. It can be prevented by.

[0006]

Since each option constrains the choice of coupler and hardener to those that do not react with each other or that do not partition into the dispersion particles, all of the above options are Not desirable. Therefore, it is desirable to prevent the reaction between the curing agent and the coupler without any restrictions on the curing agent or the coupler.

[0007]

The present invention comprises the steps of: (a) providing a silver halide photographic emulsion comprising a negatively charged coupler dispersion containing a hydrophobic hardener scavenger, and (b) an emulsion. Enough time to cure,
And a step of contacting the silver halide emulsion with a hydrophobic or positively charged hardener, to provide a method for hardening a silver halide photographic emulsion.

In some embodiments, the hardener is a carboxyl-active hardener and the hardener scavenger is a hydrophobic carboxylic acid compound. In another embodiment, the coupler is a tetravalent coupler. In another embodiment, a negatively charged hydrophobic coupler dispersion is prepared separately and then mixed with the silver halide emulsion. The hydrophobic hardener scavenger is added to the negatively charged hydrophobic coupler dispersion before the dispersion is combined with the silver halide emulsion. The present invention is
Further provided is a photographic emulsion prepared by the above method.

The present invention further provides a hardened silver halide emulsion comprising a hydrophobic hardener scavenger and a coupler dispersed in the form of hydrophobic, negatively charged dispersion particles. In some embodiments, the curative scavenger is a hydrophobic carboxylic acid compound.

[0010]

Specific Embodiment The curing agent scavenger of the present invention comprises:
Coupler A compound that competitively reacts with a hardener that partitions into droplets. The reactivity of the scavenger with the curing agent is such that the scavenger destroys a significant amount of the curing agent that partitions into the coupler droplets before the curing agent reacts with the coupler.

Hardener scavengers are hydrophobic molecules that carry one or more suitable reactive groups. The hardener scavenger must be hydrophobic, such that it is predominantly present in the hydrophobic dispersion particles to allow the scavenger to target the hardener distributed in the hydrophobic droplets. . Preferably, at least 50% of the scavengers should be so present.

The scavenger must be compatible with the photographic emulsion and element. The scavenger is
It must be substantially inert in the emulsion except that it reacts with the hardener. The scavenger must also be substantially inert during processing of the photographic element. The reactive group or groups of the scavenger must react competitively with the targeted curing agent. Hardener scavengers include a class of compounds that contain reactive groups that are specific to a class of hardeners. For example, if a carboxy activated curing agent is used, the preferred scavenger is a hydrophobic carboxylic acid compound. When vinyl sulfone or acrylate hardeners are used, the preferred scavengers are hydrophobic amines or thiols.

The hardener scavenger may be added to the coupler dispersion during dispersion preparation. The scavenger can also be added to the aqueous portion of the emulsion containing the coupler dispersion. When the scavenger is added to the aqueous portion of the emulsion, it may be added with or without a solvent. Suitable solvents are ketones or alcohols, ethyl acetate being the preferred solvent. Preferably, the scavenger is added to the coupler dispersion before it is combined with the silver halide emulsion. Most preferably, the scavenger is added to the oil portion of the dispersion component without any type of solvent prior to preparing the coupler dispersion.

The amount of scavenger added must be sufficient to effectively compete with the coupler. The preferred molar ratio of scavenger to coupler is
1: 1 to 1: 100, and more preferably 1: 2 to 1.
It is 1:20. Mixtures of scavengers from the above classes can be used in the emulsion so long as each is compatible with the hardener. If more than one hardener is used, then more than one scavenger may be used.

The preferred compounds of the present invention are described in further detail below. Useful hardener scavengers for carboxyl-activated hardeners are hydrophobic carboxylic acid compounds. These compounds may have one or more carboxyl groups. In a preferred embodiment, the carboxyl compound is
It is expressed by the following formula. Although R ¹ -CO ₂ H R ¹ it can also be a one hydrophobic group that matches the main rights on functions of the present invention, but preferably, R ¹
Represents a substituted or unsubstituted alkyl, aralkyl, aryl, alkenyl, or heterocyclic group.

More preferably, R ¹ has from 6 to 6 carbon atoms.
100 alkyls (eg hexyl, dodecyl, 2-
Hexyldecyl), aralkyl having 7 to 100 carbon atoms (eg, benzyl, phenethyl), 6 to 6 carbon atoms
100 aryls (eg phenyl, naphthyl), alkenyls having 6 to 100 carbon atoms (eg oleyl,
Linoleyl) or 6-10 carbon and heteroatoms
0 heterocyclic ring. Preferred heteroatoms are N or O. More preferable R ¹ has 8 to 24 carbon atoms.
Is an alkyl group or an aryl group having 6 to 12 carbon atoms.

Useful substituents of R ¹ include halogen, alkoxy and alkyl groups having 1 to 50 carbon atoms, and aryloxy and aryl groups having 6 to 50 carbon atoms. Preferred substituents are 1 to 1 carbon atoms.
24 alkyl groups, hydroxyl groups and halogens (preferably chlorine) are mentioned. Examples of preferred compounds are shown in Table I below.

[0018]

[Table 1]

The compounds of the above formula may be prepared by techniques known to those skilled in the chemical synthesis art. Many of these compounds are commercially available. Curing agents included in the present invention include those that are hydrophobic or have a positive charge on the central molecule. Examples of curing agents within the scope of this invention include those described in US Pat. Nos. 4,877,724, 5,071,736 and 4,863,841. . A preferred curing agent is a carboxyl activated curing agent. More preferred hardeners are dicationic ethers, and more preferred are pyridylium ethers such as those described in US Pat. No. 4,877,724. The most preferred curing agent is shown below as H-1 (bis (N-methyl-2-pyridylium tetrafluoroborate) ether). Examples of curing agents included in the present invention are shown in Table II.

[0020]

[Table 2]

[0021]

[Table 3]

[0022]

[Table 4]

These hardeners of the present invention are used as is generally known in the art. This hardener may be added to the emulsion containing the negatively charged coupler dispersion, or it may be added to another separate layer and transferred to the targeted emulsion layer. . Examples of hardeners and their uses are Kenneth
Mason Publications, Ltd., Dudley Annex, North Stre
Research Disclosure, December 1989 Item published by et, Emsworth, HampshireP010 7DQ, ENGLAND
308119, Section X. This publication will be identified hereafter by the term "Research Disclosure". The couplers of this invention can be any suitable coupler for use in a negatively charged hydrophobic dispersion in a silver halide emulsion. Examples of these couplers include, but are not limited to, Re
search Disclosure, Section VII, D, E, F and G
Sections as well as those mentioned in the publications cited herein are included. These couplers are from Research Discl
The elements and emulsions can be incorporated as described in osure, Section VII, section C and publications cited therein. This invention is described in US Pat. No. 4,863,841.
It is particularly useful in conjunction with tetravalent couplers, which tend to be more reactive with hardeners, as discussed in U.S. Pat. More preferably, the couplers of this invention are tetravalent, 5-pyrazolone couplers. These couplers have a tendency to react with certain carboxyl-activated hardeners to form color products that result in smearing. The photographic elements used in this invention can be single color elements or multicolor elements. Multicolor elements are generally three parts of the visible spectrum.
It contains dye image-forming units sensitive to each of the major areas of the seed. Each unit can comprise a single emulsion layer or multiple emulsion layers sensitive to a given region of the spectrum of interest. The layers of the element, including the image-forming unit layers, can be arranged in various orders as known in the art. In other constructions, emulsions sensitive to the three primary regions of the spectrum are provided as a single dividing layer, eg, US Pat.
Arrays can be made by using microvessels as described in US Pat. No. 2,806. The element can contain additional layers such as filter layers, interlayers, overcoats, subbing layers and the like.

The silver halide emulsions used in the elements of this invention can be either negative or positive working. Suitable emulsions and their products are available from Research D
It is described in isclosure, Sections I and II, and the publications cited herein. Some of the suitable vehicles for emulsion layers and other layers of the photographic element of the present invention are Re
It is described in search Disclosure, Section IX, and the publications cited therein.

The silver halide can be prepared by various methods (eg,
Chemical Sensitization and Spectral Sensitization (see Research Disclosure, Sections III and IV).
The photographic emulsions of the present invention or their individual layers may contain a number of optical brighteners (specific examples of Research Disclosure, Section V), antifoggants and stabilizers (Research Disclos
ure, specific examples of Section VI), stain inhibitors and image dye stabilizers (Research Disclosure, Section VII, I)
And specific examples in column J), light-absorbing substances and light-scattering substances (specific examples of Research Disclosure, Section VIII), plasticizers and lubricants (specific examples of Research Disclosure, Section XII), antistatic agents (Research Disclosure, Section).
Specific examples of XIII), matting agents (Research Disclosure, Se
ction XVI) and development modifier (Research Di
sclosure, Section XXI specific example) can be included.

The photographic elements can be coated on a variety of supports including, but not limited to, Research Disclosure, Section XVII and references cited therein. Photographic elements are exposed to actinic radiation, typically in the visible region of the spectrum, ResearchDisclo
A latent image is formed as in the sure, Section XVIII example, and then processed to produce a visible dye image.
Research Disclosure, Section XIX). Processing to produce a visible dye image includes the step of contacting the photographic element with a color developing agent to reduce developable silver halide and oxidize the color developing agent. The oxidized color developing agent in turn reacts with the dye forming coupler. In the case of negative-working silver halide, the processing steps described above give a negative image. To obtain a positive (or reversal) image, this step involves pre-development of the exposed silver halide by development with a non-color developing agent, without the formation of dyes, after which the element is uniformly fogged. Makes unexposed silver halide developable. Direct positive emulsions can also be used to obtain positive images. Development is followed by the usual steps of bleaching, fixing or bleach-fixing steps to remove silver and silver halide, and washing and drying.

[0027]

The following examples are intended to illustrate the present invention and not to limit it. Example 1 A coupler dispersion containing coupler-1 was prepared in a conventional manner. The 77 ° C. oil phase (see below) and the 50 ° C. aqueous phase (see below) were mixed with slow stirring. afterwards,
The mixture was passed through a colloid mill 5 times. Most of the ethyl acetate was removed from the dispersion by rotary evaporation at 60 ° C. using a water aspirator. Oil Phase: Additive Gram Coupler-1 60 Dibutylphthalate 30 Ethyl Acetate 120 DoxS-16 DST-1 26 Scavenger (see Tables 3 and 4 for type and amount) Water Phase: Additive Gram Gelatin 480 Alkanol XC6 Water The sample of Comparative Example 2 and the sample of the present invention in which the total amount was adjusted to 1000 g in advance with gelatin 3.
It was coated on a polyethylene-coated paper support which had been coated at 23 g / m ² . Sample 1 was prepared for comparison with the present invention. Sample 1 contained coupler-1 2.15 g / m ² , gelatin 7.53 g / m ² and hardener H-1. Samples 2-9 except that the scavenger (see Table III) was included in the dispersion.
Prepared as an example of the present invention by a method similar to Sample 1.

Samples 1 to 8 were treated at 25 ° C. and relative humidity of 50
% Aged in air. The reaction between coupler-1 and H-1 produces a yellow stain that is evidenced by increasing blue Dmin. If the reaction between coupler-1 and H-1 is low, i.e. if the hardener scavenger is effective, the blue Dmin should decrease. The blue Dmin was then measured using a reflection densitometer device equipped with a Status-A blue filter. The results are shown in Table III.

[0029]

[Table 5]

From the results in Table III, in comparison with Sample 1,
It is clear that the blue Dmin is greatly reduced in Samples 2 to 8 of the present invention. The compound causing the yellow stain in sample 1 was extracted from sample 1, followed by isolation of the colored reaction product by HPLC, followed by mass spectrometry and NM.
It was identified as D-1 (reaction product between coupler-1 and H-1) by its structure determination by R spectroscopy. Example 3 A comparative sample as well as a sample according to the invention was prepared in advance with gelatin 3.
It was coated on a polyethylene-coated paper support which had been coated at 23 g / m ² . Sample 9 was prepared for comparison with the present invention. The first layer is silver chloride emulsion 0.269 g / m ² , coupler-1 0.420 g / m ² .
m ² and gelatin 1.722 g / m ² were included. The second layer contained gelatin 1.076 g / m ² and hardener H-1. Additional samples (Samples 10-12) were prepared as examples of the invention.
These were except that scavengers (see Table IV) were included in the preparation of coupler-1 dispersions.
It was prepared in the same manner as in Sample 9.

Samples 9-12 were tested at 25 ° C. and 5% relative humidity.
It is left in 0% air for 7 days, and then exposed (S19
1B sensitometer, 3000 degree K, 2.95log
Lux, HA50 filter, 0.60 Inconel filter, NP11 filter, 21 steps 0-3.0
ND tablet, 1/10 second), and process (Cole
nta automatic processor, R
A4 processing, development at 95 ° F. for 45 seconds). Blue Dmin
Was measured using a reflectance densitometer device equipped with a Status-A blue filter. The results are shown in Table IV.
Shown in.

[0032]

[Table 6]

From the results in Table IV, it is clear that the blue Dmin is greatly reduced in Samples 10 to 12 of the present invention as compared with Sample 9. In addition to the data shown in Table IV, it was found that photosensitivity and contrast were unaffected by any amount of any scavenger. The structures of the compounds used in Coupler Dispersion Example 1 are illustrated below.

[0034]

[Chemical 1]

[0035]

[Chemical 2]

[0036]

INDUSTRIAL APPLICABILITY The present invention is a method for preventing or reducing the reaction of a coupler with a hydrophobic or negatively charged curing agent when the couplers are dispersed in the form of negatively charged hydrophobic dispersion particles. I will provide a. This is accomplished by including in the coating a hydrophobic hardener scavenger that is primarily present in the coupler dispersion. An advantage of the present invention is that it reduces the amount of reaction between the curing agent and the coupler when the curing agent is divided into dispersion particles containing the coupler. This reduces the amount of hardener and coupler destroyed and, if the reaction of hardener and coupler results in a color product, the stain produced.

Claims (2)

[Claims] 1. A process for providing a silver halide photographic emulsion comprising (a) a negatively charged hydrophobic coupler dispersion comprising a hydrophobic hardener scavenger, and (b) for curing the emulsion. A method of hardening a silver halide photographic emulsion, which comprises a step of bringing the silver halide emulsion into contact with a hardening agent which is hydrophobic or positively charged for a sufficient time. 2. A hardened silver halide photographic emulsion comprising a hydrophobic hardener scavenger and further comprising a coupler dispersed in a negatively charged hydrophobic dispersion grain.