US3081170A

US3081170A - Fog reduction in photographic silver halide emulsions

Info

Publication number: US3081170A
Application number: US765339A
Authority: US
Inventors: Emil B Rauch; Dersch Fritz
Original assignee: General Aniline and Film Corp
Current assignee: GAF Chemicals Corp
Priority date: 1958-10-06
Filing date: 1958-10-06
Publication date: 1963-03-12
Anticipated expiration: 1980-03-12
Also published as: DE1182059B

Description

United States Patent "ce This invention relates to photographic materials and to methods of preparing them. More particularly, this invention relates to light-sensitive silver halide emulsions containing as a stabilizing and antifogging agent an N- substituted-3-aminomethylazolethione.

It is well known in the photographic art that light-- sensitive emulsions, such as gelatino-silver halide emulsions, have a tendency to fog. Fog is usually caused by a prolonged ripening of the emulsion, by prolonged storage especially at elevated temperatures and humidity,

and by prolonged development. To overcome this undesirable property, it has been the practice in this art to add certain chemical compounds to the emulsions to. increase their stability and to reduce their tendency to fog. However, the stabilizing and antifogging compounds heretofore used in this art have the disadvantage that upon addition to the emulsion they cause a loss of speed and/ or contrast of the emulsion.

It is, accordindgly, an object of this invention to produce a light-sensitive emulsion which is fast, stable, has a reduced tendency to fog and has good'contrast.

A further object of this invention resides in a lightsensitive emulsion which contains a compound which stabilizes the emulsion against fogging and at the same time does not materially reduce thespeed and/ or the contrast of the emulsion.

We have discovered that N-substituted-3-aminomethylazolethiones when added to a light-sensitive silver halide emulsion, stabilize and inhibit the fogging of the emulsion.

The azolethiones, the use of which is contemplated herein, may be represented by the following formulae:

and

wherein R and R are hydrogen atoms or alkyl radicals,

e.g., methyl, ethyl, propyl, isopropyl, butyl, isobutyl,

amyl, dodecyl and the like; and acyl radical, e.g.,-acetyl, propionyl and the like; a carboxyalkoxy radical, e.g., carboxymethoxy, carboxyethoxy, carboxyprop'oxy, X represents alkyl, e.g., methyl, ethyl, propyl, isopropyl, butyl, isobutyl, amyl, isoamyl, chloroethyl, carboxymethyl, allyl; aryl, .e.g., phenyl, naphthyl, tetrahydronaphthyl, aralkyl, e.g., benzyl, phenethyl; X represents hydrogen .or a substituent having the value stated for X; and wherein X and X together represent the atoms necessary to complete a heterocyclic, hydrogenated ring system, e.g., a p'iperidine, tetrahydroquinoline, morpholine or 3,081,170 Patented Mar, 12, 1963 2 piperazine ring system, Y is an oxygen, selenium or sulfur atom, and Z represents the atoms necessary to complete a fused-0n aromatic ring system such as a benzo or naphtho ring which can be further substituted.

The following specific compounds are examples of compounds belonging to the class of compounds having the general formula given above which we have found suitable for use as stabilizing an antifogging agents:

(llHzN CH2 GH2OH2 v 3-piperidinomethyl-benzoxazole-2rthione HzN N Hz CHr-C 1 V 1, l-bisbenzoxazole-2-thione-3-methylpiperazine N HP H:

3-morpholinomethylbe DzoXazole 2-thione O 3H5 H2 v Cgl15 I 3-diethy1aminomethyl-benzoxazoIe Z-thiOne .CHrCHz CH: CHg-CH2 3-piperidinomethyl-benzothiazole-2-thlone CHzN O CHz GZ 3-morpholinomethy1-benzothlazo1e-2-thione CHzN HzN N-CH:

CHz-CH:

1,4-blsbenzothiazole-2-thione-B-methylpiperazine III OHi-OHH CHzN CH2 CHr-OH: 3-piper1dinomethyl-benzoselenazole-2-thione These compounds are prepared by reacting a 2-mercapto-substituted azole of the oxazole, benzoxazole, selenazole, benz-oselenazole, thiazole and benzothiazole series simultaneously with formaldehyde and a primary or secondary amine in the presence of a suitable solvent such as methanol, ethanol, isopropanol and the like. The preparation of these compounds is described in more detail in US. Patent 2,411,253, British patent 377,253; and Journal of the Chemical Society, 1948, page 1717.

As representatives of azoles used in the reaction the following are mentioned:

4-methyl-2-mercaptothiazole 4-ethyl-2-meroaptothiazole 4-pnopyl-2-mercaptothiazole 4-dodecyl-2-mercaptothlazole 4-buttyl-2-mercaptothi azole 4-phenyl-2-mercaptothiazole 4-p-chlorophenyl-2-mereaptothiazole 4-p-methoxyphenyl-Z-mercaptothiazole 4,5 -propano-2-mercaptothiazole 4,5 -dimethyl-2-mercaptothiazole 4,5 -:diphenyl-2-mercaptothi-azole 4,5 -diethyl-2-mercaptothiazole 5-oarbomethoxy-4-m-ethyl-Z-mercaptothiazole 5-methyl-Z-mercapbobenzothiazole 6-methyl-2-mercaptobenzothiazole 7-methyl-2-mercaptobenzothiazole 6-ter-t.-butyl-2-mercaptobenzothiazole 61phenyl-2-mercaptobenzothiazole 5-hydroxy-Z-mercaptobenzothiazole S-chloro-2-mercaptobenzothiazole S-bmomo-Z-mercaptob enzothiazole 6-chloro 2-mercaptobenzothiazole 6-bromo-2-mercaptobenzothiazole 6-nitro-2-rnercaptobenzothiazole S-amino-2-mercaptobenzothiazole 6-amino-2-mercaptobenzothiazole 6-acetamido-2-mercaptobenzothiazole 6-benzamido-2-mercaptobenzothiazole 6-dimethylamino-2-m-ercaptobenzothiazole 5-carboxyl-2-mercaptob enzothiazole 4,6adimethyl-2-rnercaptobenzothiazole 4-methyl-6-chloro-Z-mercaptobenzothiazole 5,6-dichloro-2-mercaptobenzothiazole 4-carboXy-6-chlono-2-mercaptobenzothiazole 4,6-dimethyl-7-chloro-2-rnercaptobenzothiazole 4,6-dimethyl-5,7-dichloro-3 -mercaptobenzothiazole 4,5-benzo-Z-mercaptobenzothiazole 6,7-benzo-2-mercaptobenzothiazole 2-mercapto-4,5,6,7-dibenzobenzothiazole Z-mercapto-S,6-naphthobenzothiazole 2-mercapto-5,6-benzobenZothi-azole 2-mercapto-4,5-fiuorenyl 1,2 -thiazole 6,7-benzo-2-mercaptobenzo selenazole 2-mercaptobenzoselenazole Z-mercaptos elenazole 2-meroapto-5-methoxybenzoselenazole 2-mercapto-S-methylbenzoselenazole 2-mencapto-6-methoxyquinoline 2-mercapto-6-rnethylquinoline 2-mercaptobenzoxazole 2-rnercapto-51phenylbenzoxazole 2-mencapto-S-methoxybenzoxazole 2-mercapto-S-methylbenzoxazole 2-mercapto-4,S-benzobenzoxazole The following list is representative .of primary and secondary amines, the latter including cyclic amines, which can be condensed with formaldehyde and the mercap toazoles Methylamine Ethylamine fl-Hydroxyethylamine fi-Chlo-roethylamine \Allyl-amine Benzylamine B-P-henylethylamine Ethylenediamine Ethyl amino acetate w-Aminoacetophenone Tetrahydno-fi-naphthylamine Aniline 3,4-methylene-dioxybenzyl-amine ,4 Dirnethylamine Diethylamine Diethanolarnine Dipropylamine Di-n-butylamine -Diisoamylamine Dibenzylamine methyldiethylethylenediamine Methylaniline Piperidine 1 ,2,3 ,4-tetrahydroisoquinoline 6-methoxy-1,2,3,4-tetrahydroisoquinoline Morpholine Piperiazine w-Methy-laminopnopiophenone fi-Acetylethylbenzylamine Benzyl-( 2-cyclohexanonylmethyl -amine 3,4-methylenedioxybenzyl- (2acyclohexanylm ethyl -amine The antifogging agents of our invention may be added to the emulsion at any stage during its process of production. Thus, they may be added as a ripening final or as a coating final. When added as a ripening final, they are added during the ripening or sensitivity increasing stage of the emulsion making process. Such addition may be made before, during or after the addition of the soluble silver salt to the soluble halide in the presence of a suitable colloid, such as gelatin, polyvinyl alcohol, solubilized casein or albumin. When added as a coating final, the antifogging agent of our invention is added to the emulsion just prior to coating it on a suitable support such as glass, paper, or film at a time when the emulsion has nearly attained its maximum sensitivity.

In some instances, it is advantageous to apply the antifogging and stabilizing compounds of our invention in a separate layer such as an undercoating layer or in an antiabrasion gelatin surface. Sometimes it is desirable to incorporate the compounds in one or all processing baths or in the preand post-baths.

When used as a ripening final, the antifoggants of our invention are preferably added to the emulsion in an amount ranging from 0.1 milligram to 20 milligrams per 0.6 mol of silver halide and when used as a coating final, it is preferably added in an amount ranging from 0.5 milligram .to 50 milligrams per 0.6 mol of silver halide. The optimum amount to be added depends primarily on the type of emulsion and should be determined also be used in combination with known antifoggants and stabilizers, The antifoggants of our invention can also be used in combination with sensitiz'ers such as sulfur, metal and reduction sensitizers as well as with speedincreasing agents and accelerators such as the reaction products of long-chain alcohols and ethylene oxide (see US. Patent 1,970,578) and their derivatives and polyvinyl-pyrrolidone.

The novel antifoggants of our invention may be used with various'types of photographic emulsions, such as non-sensitized orthochromatic,panchromatic and X-ray emulsions, paper emulsions and color emulsions.

The following specific examples are [given as an illustration of the manner in which the anti'foggants of our invention can be used. It is to be understood, however, that these examples are given byway of illustration and not by way of limitation.

Example I A silver halide emulsion in gelatin containing 2 percent silver iodide and 98 percent silver bromide was prepared in a conventional manner and brought up to its maximum light sensitivity. It was then readied for coating, finals were added such as sensitizing dyes and hardening agents. A 0.1 percent solution of 3-morpholinomethyl benzothiazole-Z-thione prepared according to the method described in British Patent 377,253 was added in varying amounts to .samples of the emulsion as an anti- -foggant and stabilizer. Each emulsion sample contained about 0.6 mol of silver halide. The so prepared emulsion samples were coated on a suitable cellulose ester base and dried. Samples of these film coatings were then exposed in a type IIB sensitometer and developed in a developer of the following composition:

Grains Metol 1.5 Sodiumsulfite (anhydrous) 45 Sodium bisulfite 1 Hydroquinone 6 Sodium carbonate (monohydrated) .8

Water to make -1 liter.

The developed samples were short-stopped, fixed, washed and dried. The results obtained were as follows:

Fog at 12 Oven Fog Quantity of Compound Used Relative Minute at ti Minute Speed Develop- Development ment Example II The procedure followed was identical to Example I, except that in place of 3-morpholinomethyl-benzothiazole- Z-thione' the compound used was 3-piperidinomethyl-benzoxazole-Z-thioiie prepared according to the method described in Berichte, v01. 90, page 2246.

The procedure followed was identical to Example I, but in place of 3-morpholinomethyl-benzothiazole-2- thione, the compound used was 3-dimethylaminomethyl- 6' benz-oaxazole-2-thione which had been prepared according to the method described in Berichte, vol. 90, page 2246;

The results obtained were as follows:

Example I was repeated except that 4-chl-oro-3 -morpholinomethyl-benzoxazole-2-thione was used in place of 3- morpholinomethyl-benzothiazole-Z-thione. The results obtained were essentially the same as those reported in Example I.

The compound was prepared as follows:

A solution of 4.6 grams of 4-chloro-2mercaptobenzoxaz ole and 2.4 milliliters of morpholine in 10 milliliters of methanol was cooled to about 5 C. After the addition of 3.3 milliliters of formaldehyde (37 percent) to the solution, an instantaneous reaction took place. The reaction mixture was then left standing for 2 hours at room temperature. The product which separated was recrystallized from methanol and melted at -151 C.

Example V Example I was repeated except that 6-nitno-3-piperidinomethyl-benzothiazole-Z-thione was used in place of 3- morpholinomethyl-benzothiazole-Z-thione. The results obtained were very similar to those described in Example I.

The benzothiazolethione was prepared as follows:

A suspension of 6.3 grams of 6-nitro-2-mercaptobenzothiazole in 30 milliliters 'of methanol was added to a solution of 2.5 milliliters of piperidine and 2.7 milliliters of formaldehyde (37 percent) in 10 milliliters of methanol. The reaction mixture was left for 2 hours at room temperature after the exothermic reaction had subsided. The precipitate was recrystallized from ethyl acetate and melted at 169 C.

Our invention is not limited to the detailed description contained herein, but includes all modifications that fall within the scope of the appended claims.

We claim:

1. A lightsensitive silver halide emulsion containing as an antifogging and stabilizing agent a compound selected from the group of those having the'following general chemical formulae:

l CHr-A and Y 0 2:" o=s N CHz-A and /Y Y z: o s s=o :z 0 O N omoHi N wherein X and X are selected from the group consisting of hydrogen, alkyl, aryl and aralkyl, X being a substituent other than hydrogen when X is hydrogen, and X represents the atoms necessary to complete a hydrogenated heterocyclic ring system of the piperidine and morpholine series.

2. A light-sensitive photographic element comprising a base and a coating of gelatino-silver halide emulsion thereon, said emulsion containing as an antifogging and stabilizing agent, a compound selected from the group having the following formulae:

wherein R and R are selected irom the group consisting of hydrogen, an aliphatic radical, an aromatic radical; Z represents the atoms necessary to complete a fused-on aromatic ring structure, Y is a member selected from the group consisting of oxygen and sulfur, A is a member selected from the class consisting of and wherein X and X are selected from the group consisting of hydrogen, aliphatic, aryl and aralkyl radicals, X being a substituent other than hydrogen when X is hydrogen, and wherein X represents the atoms necessary to complete a hydrogenated heterocyclic ring system of the piperidine and morpholine series.

3. A light-sensitive structure comprising a base, a

8 layer of light-sensitive silver halide emulsion thereon, and a separate layer adjacent said first mentioned layer containing as an anti-fogging and stabilizing agent com pound, a compound selected from the group having the following general chemical structures:

R-O It ("3 N Hl-A and Y z: o=s

a N 5HrA and Y Y\ 0 O z: o s s o l :2 a N OH2OH: N 5 5 H2N /N H: CH2CH2 wherein R and R are selected from the group consisting of hydrogen, an aliphatic radical, an aromatic radical; Z represents the atoms necessary to complete a fused-on aromatic ring structure, Y is a member selected from the group consisting of oxygen and sulfur, A is a member selected from the class consisting of and wherein X and X are selected from the group consisting of hydrogen, aliphatic, aryl and aralkyl radicals, X being a substituent other than hydrogen when X is hydrogen, wherein X represents the atoms necessary to complete a hydrogenated heterocyclic ring system of the piperidine and morpholine series.

4. A process of forming a photographic silver halide emulsion having a reduced tendency to fog which comprises forming the emulsion, ripening the emulsion and during said ripening adding thereto a compound selected from the group having the following general formulae:

and

. and

CH2-C a wherein R and R are selected from the group consisting or hydrogen, an aliphatic radical, an aromatic radical; Z represents the atoms necessary to complete a fused-on aromatic ring structure, Y is a member selected from the group consisting of oxygen and sulfur, A is a member selected from the class consisting of and wherein X and X; are selectedfrorn the group consisting of hydrogen, aliphatic, aryl and ara-lkyl radicals, X being a substituent other than hydrogen when X is hydrogen, and wherein X represents the atoms necessary to complete a hydrogenated heterocyclic ring system of the piperidine and morpholine series.

5. A process of forming a light-sensitive photographic element having a reduced tendency to fog which cornprises forming a silver halide emulsion, ripening said emulsion, coating said emulsion on a base and adding to said emulsion just prior to the coating thereof on the base a compound selected frorn the group having the following general formulae:

wherein R and R; are selected from the group consisting 65 10 of: hydrogen, alkyl, acyl and carboxyalkexy; Z represents the atoms necessary to complete a fused-on aromatic ring structure of the benzene and naphthalene se- =ries; Y is a member selected from the group consisting of oxygen and sulfur; A is a member selected from the class consisting of wherein X and X are selected from the group consisting of hydrogen, alkyl, aryl and aralkyl, X being a substituent other than hydrogen when X is hydrogen, and X represents the atoms necessary to complete a hydrogenated heterocyclic ring system of the piperidine and morpholine series.

6. A light-sensitive silver halide emulsion as recited in claim 1, wherein the antifogging and stabilizing compound is 3-morpholinomethyl-benzoth-iazole-2-thione.

7. A light-sensitive silver halide emulsion as recited in claim 1, wherein the antifogging and stabilizing compound is 3-piperidinome-thyl-benzoxazole-2-thione.

8. A light-sensitive halide emulsion as recited in claim 1, wherein the antifogging and stabilizing compound is 3-dimethylaminomethyl-benzoxazole-Z-thione.

9. A light-sensitive silver halide emulsion as recited in claim 1, wherein the antifogging and stabilizing compound is 3-morpholinomethylbenzoxazole-Z-thione.

10. A light-sensitive silver halide emulsion as recited in claim 1, wherein the antifogging and stabilizing compound is 3-diethylaminomethyl-benzoxazole-Z-thione.

11. A light-sensitive silver halide emulsion as recited in claim 1, wherein the antifogging and stabilizing compound is 3-piperidin0methyl-benzothiazole-Z-thione.

12. A light-sensitive silver halide emulsion as recited in claim 1, wherein the antifogging and stabilizing compound is present in the emulsion in the ratio of 0.1 to milligrams per 0.6 mol of silver halide.

13. A light-sensitive silver halide emulsion as recited in claim 1, wherein the anti-fogging and stabilizing compound is present in the emulsion in the ratio of 0.1 to 20 milligrams per 0.6 mol of silver halide.

14. A light-sensitive silver halide emulsion as recited in claim 1, wherein the antifogging and stabilizing compound is present in the emulsion in the ratio of 0.5 to 50 milligrams per 0.6 mol of silver halide.

15. A light-sensitive silver halide emulsion as recited in claim 1, wherein said emulsion is a panchromatic emulsion.

16. A light-sensitive silver halide emulsion as recited in claim 1, containing the reaction product of a long chain alcohol and ethylene oxide as an accelerator.

References Cited in the file of this patent UNITED STATES PATENTS 2,099,374 Schwarz Nov. 16, 1937 2,463,346 Russell Nov. 9, 1948 2,819,965 Murray et al. Jan. 14, 1958 2,870,015 Allen et a1. Jan. 20, 19 59 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,081,170 March 12, 1963 Emil B. Rauch et al.

It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 7, lines 55 and 56, column 8, lines 34 and 35, and column 9, lines 12 and 13, for "an aliphatic radical, an aromatic radical;", each occurrence, read alkyl, acyl and carboxyalkoxy; column 7, line 57, column 8, line 36, and column 9, line 14, for "structure,", each occurrence, read structure of the benzene and naphthalene series; column 7, line 58, column 8, line 37, and column 9, line 15, for "sulfur,",each occurrence, read sulfur; column 7, line 70, column 8, line 49, and column 9, line 26, for "aliphatic, aryl and aralkyl radicals,", each occurrence,

read alkyl, aryl and aralkyl, column 7, line 72 and column 9, line 29, strike out "wherein", each occurrence; column 8, line 51, for "wherein" read and Signed and sealed this 24th day of November 1964.

(SEAL) Attest:

ERNEST W, SWIDER EDWARD J. BRENNER Attesting Officer Commissioner of Patents

Claims

1. A LIGHT-SENSITIVE SILVER HALIDE EMULSION CONTAINING AS AN ANTIFOGGING AND STABILIZING AGENT A COMPOUND SELECTED FROM THE GROUP OF THOSE HAVING THE FOLLOWING GENERAL CHEMICAL FORMULAE: