US3894875A

US3894875A - Silver halide emulsions containing yellow dye-forming couplers exhibiting very low pH sensitivity

Info

Publication number: US3894875A
Application number: US419574A
Authority: US
Inventors: Robert G Cameron; William J Gass
Original assignee: Eastman Kodak Co
Current assignee: Eastman Kodak Co
Priority date: 1973-11-28
Filing date: 1973-11-28
Publication date: 1975-07-15
Anticipated expiration: 1992-07-15
Also published as: CA1025474A

Abstract

A class of pivalyl aryloxy ketomethylene color-forming coupler compounds exhibit high reactivity with oxidized color developer over a wide range of alkaline pH conditions. Compounds having this unique capability have the structure:

WHEREIN N IS FROM ABOUT 9 TO ABOUT 25 AND M is a monovalent cation.

Description

United States Patent [19] Cameron et al.

[451 July 15,1975

[ SILVER HALIDE EMULSIONS CONTAINING YELLOW DYE-FORMING COUPLERS EXHIBITING VERY LOW pH SENSITIVITY [75] Inventors: Robert G. Cameron, North Chili;

William J. Gass, Rochester, both of N.Y.

[73] Assignee: Eastman Kodak Company,

Rochester, N.Y.

[22] Filed: Nov. 28, 1973 [21] Appl. No.: 419,574

Primary ExaminerJ. Travis Brown Attorney, Agent, or Firm.l. T. Lewis [57] ABSTRACT A class of pivalyl aryloxy ketomethylene colorforming coupler compounds exhibit high reactivity with oxidized color developer over a wide range of alkaline pH conditions. Compounds having this unique capability have the structure:

0 n o H C1 II I wherein n is from about 9 to about 25 and M is a monovalent cation.

9 Claims, N0 Drawings SILVER HALIDE EMULSIONS CONTAINING YELLOW DYE-FORMING COUPLERS EXHIBITING VERY LOW PH SENSITIVITY This invention relates to color-forming coupler compounds having special utility in the field of photography. More particularly, the present invention relates to a special class of ketomethylene yellow dye forming compounds and to their use in photographic film elements.

Co1or-forming coupler compounds are essential components in many phases of contemporary color photography. Ordinarily, they react with oxidized aromatic amino color developing agents to yield colored dyes which contribute to the color of the photographic product. The reaction with color developing agents takes place during the development" of the photographic element, after the element has been imagewise exposed. Color developing processes have heretofore required very carefully controlled conditions of, for example, time, temperature and pH during the various steps of such processes, particularly the step during which the reaction of color-forming coupler(s) with oxidized color developer material(s) takes place; i.e., the so-called color development or development step.

One reason for carefully controlling the alkalinity or pH of developer solutions during the color development step of conventional color photographic processing is the very sharp drop-off in the color-forming efficiency of the process at relatively lower developer solution pHs. For example, although the Dmax of the yellow dye formed by reaction of a conventional yellow dye-forming coupler with a conventional oxidized aromatic amino color developer in an otherwise standardized test (which test is described in detail in Example 1, below) was 3,40 when a photographic element was developed at a pH of 11.5, the Dmax was only 1.89 when the element was developed at a pH of 10.0. Such a sharp drop-off in Dmax (with some variation in the extent of drop-off with decreasing pH from an optimum pH) can be observed almost invariably with colorforming couplers. Unfortunately the optimum pH for color development often varies somewhat, depending upon the particular color developer, color-forming coupler, or combination of couplers, being used. Such variation creates difficulties for those involved in the manufacture of new, commercially acceptable photographic products.

From this it can be appreciated that there is a present need for color-forming couplers which exhibit an insensitivity to pH over at least a large portion of the useful alkaline developer solution pH range. The existence of pH insensitive couplers would provide greater flexibility to the formulator of photographic emulsions, and to the manufacturer of color" photographic elements.

DESCRIPTION OF THE INVENTION It has now been discovered that one limited class of 2-equivalent pivalyl aryloxy ketomethylene colorforming couplers has the surprising capability of being practically insensitive to developer solution pH over a fairly wide range (i.e., pH 9 to pH 12 or wider) of developer solution alkalinities.

Compounds having this unusual capability have the structure A:

o 11 0 ll NHSVJ HIIIJ VIL.

((III I C- COOM 5 structures very similar to those of structure A apparently do not exhibit low insensitivity to pH changes.

DETAILED DESCRIPTION OF THE INVENTION This invention relates to novel coupler compounds and to photographic emulsions and elements in which such compounds are incorporated.

Although the present invention is broadly applicable to the various compounds encompassed by the formula of structure A, set out above, it is generally preferred that M be hydrogen, ammonium or an alkali metal cation such as lithium, sodium or potassium and that n is an average of from about 1 l to about 19. It is still further preferred that M is hydrogen and n is about 15. After the color-forming couplers of this invention are incorporated into a photographic emulsion, the particular identity of M is extremely difficult to determine, and is unimportant insofar as the successful practice of this invention is concerned.

The color-forming couplers of this invention are incorporated couplers which are present in the photographic element from the time of manufacture of said element through the color development step of the developing process. The couplers can be incorporated into the photographic emulsion during the emulsion manufacturing operation in any of a number of techniques such as, for example, those described in Section XXII, page of Product Licensing Index, Vol. 92, Dec. 1971. Actually, the particular technique of incorporating the present coupler materials into the photographic emulsions has little or no effect upon the successful practice of the present invention. Generally, however, photographic emulsion containing incorporated type couplers which can be dissolved in relatively high boiling coupler solvents (often with the aid of auxiliary solvents in the usual manner) are prepared by first dispersing in aqueous gelatin solutions the coupler (dissolved in a solvent comprising a high boiling crystalloidal coupler solvent and an auxiliary organic coupler solvent having substantial solubility), then causing the resulting coupler dispersion in gelatin to set, washing this set dispersion to remove a substantial amount of the auxiliary solvent with an aqueous solution (at a pH within about 0.5 units of the isoelectric point of the gelatin) of a carboxylic acid having 2-8 carbon atoms such as propionic acid, and subsequently blending the washed dispersion with a gelatino silver halide emulsion.

Similarly, the other specific components which are present in the photographic emulsions and elements of this invention are not critical with respect to the present invention so long as the emulsions are photosensitive silver halide emulsions. Such emulsions contain hydrophilic colloid such as gelatin and can contain addenda, as desired, such as hardeners, antifoggants, sensitizing dyes, chemical sensitizers, coating aids, plasticizers, coupler solvents, matting agents, brightcners, and the like without distracting excessively from the successful practice of the invention. Many examples of such hydrophilic colloids and addenda, and means for their use can be found in Product Licensing lndcx, Vol. 92, December 1971, pages l071 l0, publication 9232.

The present couplers are ballasted in that they remain essentially immovable in the emulsion, after the emulsion is dried. These couplers convert into a yellow dye upon reaction with oxidized color developer. For example, upon reaction with N,',1\l-diethylamino-pphenylene diamine, the coupler of Structure A wherein M is hydrogen and n is 15 is converted into a very desirable yellow dye having a peak absorbance at 444.1 nanometers. Because of their yellow dye-producing capability the couplers of this invention are almost invariably incorporated into the so-called blue sensitive layer ofa 3-color photographic element. Generally, this blue-sensitive layer is the topmost layer of a three layer element (which may contain additional layers over, between and under the three basic color-forming layers, as desired), the remaining color-forming layers being green-sensitive and red-sensitive," in the typical, wellknown fashion.

The photographic emulsions of this invention (which contain the color-forming coupler compounds of Structure A) are generally coated in any desired manner in the form of at least one layer on a photographic support. The particular support that is used is not important with respect to the successful practice of this invention. Typical photographic supports are described and referred to in Product Licensing Index, Vol. 92, Dec. 1971, Section X.

Organic amino aromatic color developing materials are well known in the art and need not be described in detail here. The couplers of the present invention can be developed" with solutions containing any organic amino aromatic color developing material that is useful for conventionally color developing photographic elements containing incorporated colorforming couplers. Typical, non-limiting examples of such organic amino aromatic color developing materials include paminophenol, p-phenylenediamine and N,N-diethyl-pphenylenediamine. It should also be noted that, manipulatively, conventional color development processes can be used successfully to develop photographic elements containing the present couplers incorporated in at least one of the layers thereof.

EXAMPLE 1n the following example, all parts given are by weight unless otherwise specified.

A. A series of photographic elements were prepared by coating in a conventional manner onto a conventional cellulose acetate film support layers of photographic emulsions, each containing 1l.l mg/sq. decimeter of silver (as iodobromide) and 2.8 X 10' moles/sq decimeter of yellow dye-forming coupler. Each of the element samples contained a different coupler, identified as Coupler 1 through 13, below. The couplers were incorporated into the emulsion by the method set out in US Pat. No. 2,322,027.

B. Each of the elements manufactured in accordance with part A of this example was cut into four segments, exposed to a conventional graduated density test objcct, and then developed for 4 minutes using Kodak CD-3 Developer and processed completely in a conventional way. However, prior to the developing step, the pH developer solution was adjusted by conventional means to pHs of 10.1; 10.5; 11.0; and 11.5. In Table 1, below, are set out the values for Dmax of each of the elements prepared as in paragraph A of this example.

Kodak CD-3 Developer is a solution of 4.5 g sodium sulfite, 36 g anhydrous potassium carbonate, 0.75 g potassium bromide, 0.09 g potassium iodide, 1.0 g dithiaoctanediol, 0.1 g tetramethyl ammonium hydrotriborate, and 7.0 g 4-amino-3-methyl-N-ethyl-B-(methanesulfonamido)ethylaniline sesquisulfate in water, made to 1 liter.

"pH of developer solution From the data in Table 1, it can readily be appreciated that only coupler number 1 shows consistent nonsensitivity to variations in the pH of developer solutions through the developer solution pH range of from 10 to 1 1.5, while coupler No. 14 demonstrates only a slight tendency to lose Dmax with decreasing developer alkalinity. The couplers used in this test are identified below. While this test was made using only one color developer solution, it is believed that similar comparative results would be obtained using other color developer solutions.

Coupler No. 1

nso c n COOH a-Pivalyl-a-(p-carboxyphenoxy)-2-chloro-5-(nhexadecanesulfonamido )acetanilide Coupler No. I I Coupler No.

II II Coupler N0 7 OCH HC-CHZ-OQ C H Coupler No.

(CH3) ccpucwn Q COOII scribed in US Pat. No 3.265506 and 3.408l94 for example.

The invention has been described in detail with particular reference to preferred embodiments thereof, but, it will be understood that variations and modifications can be effected within the spirit and scope of the invention.

What is claimed is:

l. A light-sensitive silver halide emulsion containing a color-forming coupler compound capable of high reactivity over a wide alkaline pH range; said coupler having the structure:

cn o n 0 ll U I n n v y-q CH -C C C C N O O 3 I I H CH ('3 l:l [Cll '--Cll COOM wherein n is an integer from about 9 to about 25 and M is hydrogen or a monovalent cation.

2. A-light-sensitive silver halide emulsion as in claim 1, wherein n is from about 11 to about 19.

3. A light-sensitive silver halide emulsion as in claim 1, wherein n is about 15.

4. A light-sensitive silver halide emulsion as in claim 1, wherein n is about I l.

5. A photographic element comprising a photographic support coated with at least one photosensitive silver halide emulsion layer; said layer containing lightsensitive silver halide, hydrophilic colloid, and a coloring couplers, so that competing couplers appear to 40 forming coupler having the structure:

have relatively little effect on the yellow dye Dmax that can be formed in photographic elements in which the present coupler compounds are incorporated. This particular capability of the coupler compounds of this invention (and some other yellow dye-forming coupler compounds) is detailed at greater length in copending US. Pat. application Ser. No. 419,573, filed concurrently herewith, now abandoned, and entitled Photographic Elements Containing Color-Forming Couplers Having An Inhibiting Effect Upon the Reactivity of Competing Couplers.

The color coupler compounds of this invention can be made by well-known procedures such as those dewherein n is an integer from about 9 to about 25 and M is hydrogen or a monovalent cation.

6. A photographic element as in claim 5, wherein said color-forming coupler is present in said layer in an amount equal to about 3 X 10" moles per square decimeter.

7. A photographic element as in claim 6, wherein said n is from about 11 to about 19.

8. A photographic element as in claim 6, wherein said n is about 15.

9. A light-sensitive silver halide emulsion as in claim 6, wherein n is about 1 l.

Claims

1. A LIGHT-SENSITIVE SILVER HALIDE EMULSION CONTAINING A COLOR-FORMING COUPLER COMPOUND CAPABLE OF HIGH REACTIVITY OVER A WIDE ALKALINE PH RANGE, SAID COUPLER HAVING THE STRUCTURE:

2. A light-sensitive silver halide emulsion as in claim 1, wherein n is from about 11 to about 19.

4. A light-sensitive silver halide emulsion as in claim 1, wherein n is about 11.

5. A photographic element comprising a photographic support coated with at least one photosensitive silver halide emulsion layer; said layer containing lightsensitive silver halide, hydrophilic colloid, and a color-forming coupler having the structure:

6. A photographic element as in claim 5, wherein said color-forming coupler is present in said layer in an amount equal to about 3 X 10 5 moles per square decimeter.

8. A photographic element as in claim 6, wherein said n is about 15.

9. A light-sensitive silver halide emUlsion as in claim 6, wherein n is about 11.