US2271622A

US2271622A - Photographic emulsion

Info

Publication number: US2271622A
Application number: US321593A
Authority: US
Inventors: Burt H Carroll; Charles F H Allen
Original assignee: Eastman Kodak Co
Current assignee: Eastman Kodak Co
Priority date: 1940-02-29
Filing date: 1940-02-29
Publication date: 1942-02-03
Anticipated expiration: 1959-02-03
Also published as: FR949229A; GB556458A

Description

Patented Feb. 3, 1942 PHOTOGRAPHIC EMULSION Burt H. Carroll and Charles F. H. Allen, Rochester,-N. Y., assignors to Eastman Kodak Com-- pany, Rochester, N. Y., a corporation of New Jersey No Drawing. Application February 29, 1940,;

Serial No. 321,593

. l Claims. This invention. relates to photographic emulsions and more particularly to photographic emulsions of the silver halide type.

It is known that the inherent sensitivity of photographic silver halide emulsions (whether spectrally sensitized or not) can be enhanced, and there has been a constanteiiort to obtain higher speeds in photographic emulsions. For

example, it is-known that the speed of gelatino- -silver-halide emulsions can be enhanced by an extended digestion or ripening of the emulsion. It is also known that the speed of silver halide emulsions (spectrally sensitized or not) can vbe enhanced by incorporating in the emulsions compounds containing a divalent atom of the sulfur group directly joined by a double bond to a single metalloid atom to which is attached at least another group of atoms. Examples of such compounds are allyl isothiocyanate and allylthiourea. s

We have now found that the speed of photographic silver halide emulsions can be increased by incorporating in the emulsions (spectrally sensitized or not) surface active substances, such as aqueous-dispersing or wetting agents, of the cationic phosphonium salt type. (Surface active substances are classified as anionic or cationic The surface-active substances act on the emulsion in unknown manner to increase its effective sensitivity. As a result, the sensitivity is provement over supersensitized emulsions known in the art. The increases in sensitivity which can be attained with-supersensitizing combinaincreased by about the same amount at any substances and spectral (optical) sensitizers as combinations, although we do not intend to imply that the surface-active substances andv the spectral sensitizer are chemically combined.

Our new. supersensitized emulsions are an imtions of dyes can be enhanced by our new method. Furthermore, whereas with supersensitizing combinations of sensitizing dyes (see United States Patents 2,075,047, 2,075,048 and 2,075,049,

each dated March 30, 1937), the supersensitizing effect is confined more or less to a single spectral region, the supersensiti'zation attained in our new emulsions extends throughout the entire region in which the spectral sensitizer acts (and is fairly uniform in degree throughout the entire region), while at the same time the sensitivity in the violet and blue region (where the spectral sensitizer does not act) is also enhanced about to the same degree.

in a suitable solvent, such as water or methyl alcohol. The surface-active substance should be thoroughly incorporated in the emulsion. The

surface active substance 'can be added to the I finished emulsion or at any stage of the preparation of the emulsion.

In the case of spectrally sensitized emulsions,

' the surface-active substance can be incorporated in the emulsion before, simultaneously with, or'

after the sensitizing dye, although in some cases as hereinafter set forth, it is advantageous to incorporate the sensitizing dye before incorporating the surface-active substance. The methods of incorporating sensitizing dyes in emulsionsare, of course, well known to those skilled in the art. Ordinarily, it is advantageous to employ a solution of the sensitizing dye in a suitable solvent, e. g. methyl alcohol. Ethyl alcohol or acetone may be employed in cases where the ,solubility of the sensitizing dye in methyl alcohol is very low, or any other suitable solvent or other procedure may be used.

sensitizing dyes are ordinarily incorporated inthe washed, finished emulsions. and in accordance with our invention, the surface-active substances are advantageously also incorporated in q the washed, finished emulsions. However, the

surface-active substances can-be added to the emulsion during the preparation thereof, 1. e..

during the precipitation of the silver halide, the

' mono salts.

mono salts, the phosphonium cation should advantageously contain at least seven, eight or more members. Advantageously, such members are from the group consisting of carbon, oxygen, nitrogen and sulfur atoms. One or more aromatic rings, such as a benzene ring, for example, can take the place of on or more of the weight or more atoms. Thus, a benzene ring can take the place of one atom, while a naphthalene ring (two benzene rings fused together) can take the place of two atoms. The atoms attached to the eight or more atoms in the chain (where valence permits) can be hydrogen, oxygen, sulfur, carbon or halogen, for example. Any aromatic ring system in the chain can carry simple substituents. We have found that cationic phosphonium salt surface-active substances having a phosphonium cation containing a lipophylic organic group which contains a chain composed of from nine to twelve members selected from the group consisting of carbon atoms, oxygen atoms, sulfur atoms and aromatic ring system are advantageously employed.

In the case of "poly salts described in examples hereinafter and also in a copending application filed of even date in the names of the same inventors, other proportions and the like may be used. For example, in the case of agents having a bivalent organic radical having a chain of 1-6 members, amounts of 400 mg. may be employed. In the instance of chains of 7-14 members smaller amounts would be preferred, as will be discussed hereinafter with respect to the The anion may be any acidradical, such as chloride, bromide, iodide, p-toluenesulfonate, perchlorate or alkylsulfate for example. Of course, introduction of halide anions into photographic silver halide emulsions alters the halide concentration in the emulsion and compensating Nonyl, CHa-(CI-Iz) a-(nine atom chain).

Decyl, CHa(CHz)o-(ten atom chain).

Lauryl, CHa(CHz)11-(twelve atom chain).

Cetyl, CI-I3(CH:)15(sixteen atom chain).

Heptoxymethyl, CHs (CHz)e-O-CHz-(nine atom chain).

Undecoxymethyl, CHa-(CHz) 1c0--CHz(thirteen atom chain).

Heptylthiomethyl, CH3(CH2) e-SCH2 (nine atom chain).

Carbononoxymethyl cH@(cH, ,-o-c :-cH:-

0 (twelve atom chain). Caproiixyethyl CHa-(CHDc-C-O-CHr-CHz- (nine atom chain). Butoxyethoxyethyl, CHa(CH2) aO-(CH:) a

OCH2-CH2(ten atom chain). Ter-butylphenoxyethoxyethyl (eight atom+phenyl group chain). Formylphenyloxyethoxyethyl (seven atom+phenyl group chain). Phenylphenoxyethoxyethyl (six atom-i-two phenyl groups chain). Methylphenoxypropoxypropyl (nine atom+phenyl group chain). 3,7-dimethyloctanoxymethyl GHr-CH-CHr-OHr-CIL-CH OH-OH.00Hr- I Q Hi HI (ten atom chain). Citronelloxymethyl CH:=CHCHr-CHz-CHz-CH-CHrCHr-O-CHr H; Hr

(ten atom chain).

(Alcohol radicals in commercial oil of san wood)-O-CHz--(at least ten atom chain).

en atom chain) p-Naphthoxyethoxyethyl (six atom two phenyl group chain). We have found it advantageous to incorporate spectral sensitizers in the photographic emulsions prior to incorporation of the perchlorate surfaceactive substances. With surface-active substances containing anions other than perchlorate.

. the order of incorporation of the surface-active substance with respect to the spectral sensitizer appears to be of small moment.

The quantity of surface-active substance which is most advantageously employed varies with the nature of the surface-active substance and with the nature of the emulsion. Ordinarily, the most advantageous concentration was found to be between about 20 mg. and about 200 mg. of the surface-active substance per gram-mole of silver halide in the emulsion, although greater or smaller concentrations. can be employed. We have found that excesses of the surface-active substance are advantageously avoided, since excesses'produce fog in the emulsions; For surface-active substances containing a lipophylic group containing a chain of eight to ten memben, we have found-thatas *much'asabout 400 mg. of surface-active substance per gram-mole of silver halide in the emulsion can ordinarily be employed without encountering excessive fog,

while with surface-active substances-containing. a lipophylic group containing a chain of eleven to twelve or more-members, we have'found that not more than about 200 mg. of surface-active substance per. gram-mole of silverhalide shouldordinarily be employed.

The preferred amounts withrespect to they "poly salts (which may or may not be surface active) have already been described, andindicate to some extent the variation with the nature of the salt. I

The optimum range of'concentration for any particular surface-active substance described herein is ordinarily fairly narrow and can best be determined byemploying -a-seriesof concentrations of the surface-active substances, separately of course, well known to those skilled in the art.

Briefly; the method of determining sensitivity of comprises coating the emulsion onto a glass plate to a suitable thickness and drying the coated emulsion and then testing the resulting photographic plate in a wedge spectrograph and a sensitometer, whereby spectral sensitivity and speed of the emulsion on the plate is determined.

When employing spectrally sensitized emulsions, the spectral sensitizers (sensitizing dyes) are advantageously employed in about their optimum concentration, which ordinarily lies between about 3 mg. and mg. of spectral sensitizer'per liter of emulsion containing about 0.25 grammole of silver halide, although concentrations above or below the optimum concentration can be employed. with line-grain emulsions, which in- I eludes most' of the ordinarily employed silver chloride emulsions, the ratio of concentration of sensitizing dye to the. concentration of silver halide in the emulsion is advantageously larger than in the coarser grain emulsions where,

iicial eifect on the" emission." As non-acidic sensitizing dyes, we include all the knownneutral and basic. sensitizing dyes: ii those sensitizing dyes which do notg'ive" colored anions. Some of these non-acidic sensitizingjjdyes,--such'as the cyanine dyes, give colored cations. "Exemplary of the non-acidic sensitizing dyes are the sensitizing cyanlne cl'yes (see, for example, United States I Patents 1,846,300, 1,846,301, 1,846,302,-1,846,303

smaller amounts. of sensitizing dyes. usually give optimum sensitization. The optimum concentration, as-above referred to, ofa sensitizing dye (i. e. the concentration at which greatest sensitivity occurs) can be readily determined inamanner well known to those skilled in the. art by measuring the sensitivity of a series of emulsions containing different concentrations of the sensitizing dye.

Our invention is directed particularly to the silver halide developing-out emulsions customarily employed in the art, including the gelatinosilver-chloride, the gelatino-silver-bromide and 'the gelatino-silver-bromiodide' developing-out emulsions, for example. However, our invention can be employed with silver halide emulsions wherein the carrier is other than gelatin, for example, a resinous or cellulosic. derivative substance which has substantially no deleterious effect on the light-sensitive materials in the emulsions.

As spectral practicing our invention. sensitizing dyes, such as Congored,whicl'1 disperse in water to give a colored anion, i. e. acidic sensitizing dyes, appear to interfere with the surface-active agent, with the result that neither the acid dye nor the surface-active substance exert a substantially benee and 1,846,304, each. dated February'23,'1932, United States Patent 1,861,836, dated June 7, 1932, United States Patent-1,939,201, dated December 12, 1933, United States Patent.1,942-,854, dated. January 9, 1934, United States Patent 1,957,869, dated'May 8, 1934, United States Patent 1,962,124, dated June 12, 1934, United States Patent 1,969,446, dated August 7, 1934, United States Patent 1,973,462, dated September 11, 1934; United States Patent-1,990,507, dated February 12, .1935, United States Patent 2,094,580,v

dated October 5, 1937, United States Patent 2,112,140, dated March ,22, 1938 and French Patent 757,813, published January 5, 1934),.the

sensitizing merocyanine dyes.(see United States Patent 2,078,233, dated April 27,1937, United State Patent 2,089,729, dated August 10, 1937,

United States Patent 2,153,169, dated April 4, f

1939 and United States Patents 2,177,401; 2,177,402, and 2,177,403, dated October 24, 1939) the sensitizing hemicyanine dyes (see United J 7 States Patent 2,166,736, dated Jilly 18, 1939) and the sensitizing hemioxonol dyes, (see United States Patent 2,165,339, dated July 11, '1939 and French Patent 841,632, published May 24, 1939) A further understanding of our invention will be had from a consideration'of the following ex-' amples. It is to be understood that these ex-' amples are'set forth primarily for the purposes of illustrating preferred embodiments and not for limiting our invention.

While phosphonium compounds from any source, as long as they areof satisfactory purity and otherwise meet photographic specifications,

may be employed, we describe herein examples of y the manufacture of certain of our compounds. The several examples immediately following,.are illustrations of some of the procedures which may be followed in making various phosphonium derivatives'useful in practicing our invention.

Exams: 1. n-Dodecyltriethylphosph'onium bromide The mixture was heated under reflux at 125 C.

' for 2 hours. on cooling the mass solidified and sensitize rs (sensiti zlng dyes) only those which are non-acidic can be employed in 3% parts of n-dodecyltriethylphosphonium bro-lmide was collected by .treatingwith anhydrous ether. I

Exurru: 2.n-Dodecyltriethylplgosphonium perchlorate Approximately '2 parts of n'-dodecyltriethylphosphonium bromide (from Example 1) was.

treated in 5 parts of methyl alcohol with 2 parts ofsodium perchlorate in 5'pa'rts of warm water and chilled. By this treatment there is obtained l-2 parts of 'n-dodecyltrithylphosphonium perchlorate, melting at 70 (3,

. Exmrts 3.-n -Decyltriethylphosphonidm p-toluenesullonate A mixture of 4 mshsema triethylphosphine (obtained by the action of phosphorus tribromide at 125-l35 C.under reflux. While still 'warm better understanding of our invention, we, set

forth an example describing the specific addition of one of our reagents'to a certain photographic emulsion. Likewise, it is to be understood that the product was treated with 15 parts of acetone 5 this example is set forth merely for the purpose which efiected solution. There was then added of illustration 'and is not to be considered'a re- 30 parts of ether, and on. chilling 4 parts of a striction on our invention.

white salt melting at 61-65 C. crystallized. It Emil: 6

was essentially n-decyltriethylphosphonium ptoluenesulfonate, 10 A highly sensitive silver bromiodide gelatin was optically sensitized to give a panchromatic sensigf m fsf'gfx tization and divided into two portions. One of e i v the portions was employed as a control. To the To 6 partsof crude triethylphosphine (obother portion was added approximately 10 mg. tained by the action of phosphorus tribromide per liter. of n-lauryltriethylphosphonium broon ethylmagnesium bromide) was added 6 parts mide, in accordance with our invention; Several of decamethylene bromide and the mixture plates were coated from each portion aforedewarmed slightly. A vigorous reaction set in and scribed, dried together, exposed together, and

a white solid separated. After cooling, the repro ss d together. in order t t all nd ns action product was dissolved in parts of meth- 20 would be comparable and the beneficial efiects yl alcohol and allowed to stand until the bulk of our novel addition f. ph p ni compounds of the alcohol had evaporated. It was then r y p r treated with 20 parts of ether, and the white p n t s n h p ss p a s. t u ms crystalline material resulting was collected on a Sensitivitles noted were as 1 filter, There was thus obtained 10 parts of tetramethylene-bis-triethylphosphonium brom- Speed 1 r ide melting at 158 C.

Exem t: 5. hillene-bis-ory e hyltriethylfififititsiimaattainments;165.51 7

. phosphoiiium chloride 1,860 pazts :2 i ether l of triezhyl Various other phosphonium compounds could f g con a g an l g' of be incorporated in a similar manner, as for exg 3 8 .f e ample n-lauryltriethylphosphonium perchlorate, oxyme y c or e and 6 mm um warme to n-decyltriethylphosphonium p-toluen'esulfonate remove etherand then heated under reflux for or tetramethylene bis phosphonium perchloram 3 hours at 120 By treating the product with In all instances, our novel treatment of photoacetone and ether there .was obtained. a small graphic materials with phosphonium compounds amount of white solid melting with f not only improved the speed of sensitized emultion at 160 C. It was essentially ethylene-bissions but even sensitized emulglona The oxymethyl-triethylphosphonium chloride. 7 40 movement as indicated in the cifi atio with Particular reference to Example 2, further tended over the entire region, even into the violet details respecting the production of perchlorate a blue region and enhanced t en itivity derivatives are Set forth in Allen and Wilson about the same over the entire region. Furtherapplication entitled Surface-active materials, more, t 111 be t d that the improvement may filed of even date. 40 .amount to 25% or more.

As already Pointed t. the phosphonillm com- Still further illustrations of our invention are p d mixture pounds to be added to set forth for convenience in the following table.

the photographic material may be added in var- It will be. observed from the disclosure in the ious ways, various amounts, in the presence of table that both sensitized and unsensitized photodye sensitizers, or otherwise. However, for a graphic emulsions were treated.

(White light White light minus blue) Emulsion sensitizing dye Surface active agent 12 Speed Gamma Fog Speed Gamma Highly sensitive gelatlno-sil- 2-diphenylamino-fi-(z-ethyl-l- None 455 0.82 .06 126 0.8

ver-bromiodide. benzothiazylidene ethylidene)-4-(6)-thiazolone, 15 mg./iiter. Do do Tetramethylene his triethyl 590 0.88 .06 200 0.81 v phosphonium *bromide 30 rug/liter. Do l,2-diethyl-3,4-benzothia-2- None 280 0.82 .08 as 0.77

fiytglnine iodide, 15 mg./ Do "do Tetrlmethylene bis triethyl I 72s 0.00 .07 0.78

pho7lphonium bromide, 30 mg. iter.

Do 2,7-dimethyl-8-ethyl thiacar- None 525 0.61 .07 132 0.62

lliizg yanine bromide, 15 mg./ Db .do 'letmmethylene bis trietbyl 015 0.70 .0a 178 0.79

' Mama Ilium bromide Do Unsensitiwd emulsion are iii 000 0.01 .04 Do ..do Totramotliyienc bis trietiiyl 830 0.60 .06

' g alumni bromide 30 Therefore, it will be seen that we have found' that a substantial improvement may be made in photographic emulsions by incorporating a phosphonium compound or compounds therein in various ways. As indicated,- in the instance where the photographic material contains a sensitizing dye, it is preferred to incorporate the dye sensitizer first and thereafter incorporate the phosphonium surface-active substance.

In the production of our various compounds, in place of the ethersolvent, other suitable solvent may be employed. Or, other changes may be made in the process.

It is apparent from the foregoing'that our in vention is susceptible of some modification and hence is not to be restricted excepting insofar as may be necessitated by the prior art and the spirit of the appended claims.

.What we claim as our invention and desire to be secured by Letters Patent of the United States 1. A photographic. silver halide emulsion sensitized with a cationic surface-active phosphonium salt.

2. A photographic silver halide developing-out emulsion sensitized with a cationic surface-active phosphonium salt.

3. A photographic gelatino-siiver halide emulsion sensitized with a. cationic surface-active phosphonium salt.

4. A photographic gelatino-silver-halide developingrout emulsion sensitized with a cationic surface-active phosphonium salt.

5. A photographic gelatino-silver-halide emulsion sensitized with a supersensitizing combina tion of at least one non-acidic sensitizing dye together with a cationic surface-active phosphonium salt.

6. A photographic silver halide emulsion sensitized with a cationic surface-active quaternary phosphonium salt.

7. A photographic silver halide developing-out emulsion sensitized with a cationic surface-active quaternary phosphonium salt.

8. A photographic gelatino-silver-halide emulsion sensitized with a cationic surface-active quaternary phosphonium salt.

9. A photographic gelatino-silver-halide developing-out emulsion sensitized with a cationic surface-active quaternary phosphonium salt.

10. "A photographic silver halide emulsion sensitized with a supersensitizing combination of at least one non-acidic sensitizing dye together with a cationic surface-active quaternary phosphonium salt.

11. A photographic gelatino-silver-halide emulsion sensitized with a super-sensitizing combination of at ,least one non-acidic sensitizing dye together with a cationic surface-active quaternary phosphonium salt.

12. A photographic emulsion sensitized with a supersensitizing combination of a non-acidic sensitizing dye together with a cationic surface active quaternary phosphonium salt, thejcation of which contains at least one organic group containing a chain of at least eight members selected from the group consisting of carbon atoms, oxygen atoms, sulfur atoms, nitrogen atoms and benzene nuclei.

13. A photographic gelatino silver -halide emulsion sensitized with a supersensitizing combination of a non-acidic sensitizing dye together with a cationic surface active quaternary phosphonium salt, the cation of which contains at least one organic group containing a chain of from eight to twelve members selected from the .group consisting of carbon atoms, sulfur atoms,

oxygen atoms, nitrogen atoms and benzene nuclei.

14. A photographic gelatino silver halide emulsion sensitized with at least one non-acidic sensitizing dye and containing, in a concentration of from about 20 ,to about 400 milligrams per gram-mole of silver halide in the emulsion, a cationic surface active quaternary phosphonium salt, the cation of which contains at least one organic group containing a chain of from 8 to 10 members'selected from the group consisting of carbon atoms, sulfur atoms, oxygen atoms, nitrogen atoms and benzene nuclei.

15. A photographic gelatino silver halide emulsion sensitized with at least one non-acidicgelatino-silver-halide