Photographic material containing aliphatic perfluoro compounds

United States Patent Office _Pate„_ted

3,666,478 PHOTOGRAPHIC MATERIAL CONTAINING ALIPHATIC PERFLUORO COMPOUNDS Margit Groh, Bourguillon, and Alfred Oetiker, Fribourg, Switzerland, assignors to Ciba Limited, Basel, Swit- ⁵zerland • No Drawing. Filed Sept 18, 1969, Ser. No. 859,166 Claims priority, application Switzerland, Sept. 24, 1968, 14,256/68

Int Cl. G03c 1/38 ₁₀

U.S. a. 96—114.5 3 Claims

ABSTRACT OF THE DISCLOSURE

Photographic material, preferably for the silver dyestuff 15 bleaching method, is provided which contains in at least one gelatine-containing layer as a wetting agent a watersoluble, surface-active perfluoro compound. With these wetting agents a very good uniformity of the applied gelatine layers is achieved. 20 . The present invention relates to a light-sensitive photographic material and to a process for its manufacture. It especially relates to the use of surface-active substances as auxiliary agents when coating films and papers with gelatine-containing light-sensitive layers and gelatine-containiny auxiliary layers. Possible light-sensitive layers are preferably silver halide-containing layers, whilst possible auxiliary layers are backing layers, substrata, intermedi- ³⁰ate layers, covering layers, filter layers and transfer layers.

It is usual to add surface-active substances to photographic gelatine solutions in order to assist the uniform wetting of film, paper or layers which already cover these supports. The wetting of the finished cast layers by processing baths is also intended to be assisted by surfaceactive substances in the layers. Numerous surface-active agents have already been proposed as additives to the casting solution, such as, for example, saponin and also ₄θ a large number of synthetic anionic, cationic and nonionic substances.

The demands made on surface-active substances are very diverse. They must be obtainable in a quality which always remains constant, which is not the case for natural products such as saponin. They must be photographically harmless and must not have any disadvantageous effect on the sensitivity, gradation, haze and storage life of the photographic emulsions. They must be compatible with emulsion additives, for example, hardeners, sensi- _goUsers, coupling agents and dyestuffs. Furthermore they must improve the physical properties of the casting solutions to a sufficient extent in order to fulfil their purpose; that is to say, they must make uniform castings possible, which are free from streaks, repelled material (comets) _ggand foam (small bubbles), and which adhere well to the substrate. At the present time especially high demands are made of such surface-active compounds since thinner layers and higher casting speeds are constantly being adopted, with a further aim being to cast layers without θθ waiting for the drying of the previously cast layers.

In particular, the manufacture of uniform layers for the silver dyestuff bleaching process presents difficulties, since the casting solutions contain water-soluble azo dyestuffs which undergo mutual interactions with the gela- _ggtine and hence unfavourably influence the flow properties ⁰of the casting solutions.

The present invention is based on the observation that perfluorinated aliphatic compounds of non-ionic or anionic character can advantagesously be employed as wet- γθ ting agents in photographic, gelatine-containing, casting solutions, with a much better uniformity of the applied '

layers being attainable than is possible with the wetting agents usually employed in photographic processes. The present invention thus provides a process for casting photographic, gelatine-containing casting solutions, especially for the manufacture of photographic material for the silver dyestuff bleaching process, wherein at least one water-soluble surface-active, nonionic or anionic, aliphatic perfluoro compound is used as the wetting agent. The layers manufactured with such wetting agents, especially also those containing azo dyestuffs for the silver dyestuff bleaching process, are essentially free from faults, for example, streaks, dot-shaped repelled material and small bubbles.

Preferably, the aliphatic perfluoro compounds to be used as wetting agents in accordance with the invention correspond to the formula (1) Ry—Z wherein Ry represents a perfluorinated alkyl residue and Z represents an optionally further-substituted carboxylic acid or sulphonic acid residue. Thus the perfluoro compounds are preferably perfluorinated aliphatic carboxylic acids, sulphonic acids, carboxylic acid-amidocarboxylic acids, sulphonic acid-amidocarboxylic acids or the salts of these acids, or sulphonic acid amides, carboxylic acid amides, carboxylic acid esters or urethanes. Further possibilities are also perfluorophosphoric acid esters. By perfluoro compounds there are to be understood compounds which are fluorinated as completely as possible, that is to say, especially compounds which apart from an optionally further-substituted functional group exclusively contain fluorine atoms as substituents. Compounds which are not completely fluorinated however also fall under this concept, such as, for example, compounds which possess a terminal hydrogen atom, a so-called ω-Η, in the fluorine-containing residue. Such compounds are also called ω-Η-perfluorinated compounds.

Anionic or anion-active perfluoro compounds for example correspond to the formulae (2) Rf—co—o-x (3) Rf—SOj—o—x (4) Rf-CO-N—R1-C0-0-X

Rs and above all (S) Rf—SOa—N—Ri—CO—0—x

I Rs

Ry represents an alkyl residue which is perfluorinated in the manner indicated, R_r represents an alkylene residue, R₂ represents a hydrogen atom or an alkyl residue and X represents a hydrogen atom or an alkali metal atom.

Non-ionic or non-ionogenic perfluoro compounds for example correspond to the formulae (6) Rs ' Rf—80s—N (7) R₂

Rf—CO—1Z ^XRs (8) Rf—CO—0—Ri (9) Ri-O-OC-Rs and (10) Rf-0-OC-Rf

Ry represents an alkyl residue which is perfluorinated in the manner indicated, R₂ and R₃ each represents a hydrogen atom or an alkyl residue and R₄ represents an alkyl residue.

3,666,478

The alkyl residues in Formulae 3 to 9 can also be further substituted, for example by further functional groups.Preferably, Ry represents a residue of formula (Ila) F—(CF₂)_n— or (lib) H—(CF₂)_n— wherein n represents an integer having a value of 3 to 9.

Preferred representatives of the Formulae 2 to 5 for example correspond to the formulae (12) Rf—CO—0—Me (13) Rf—S0₂— 0—Me (14) Rp—CO—N—(CH₂)„—CO—0—Me

Rs and especially (15) Bf^-- SOa—N—(CHjJm—CO—0—Me

Bs wherein R_P has the meaning given above, R_s represents a hydrogen atom, a methyl residue or an ethyl residue, m represents an integer having a value of 1 to 6 and Me represents an alkali metal atom.

Preferred representatives of the Formulae 6 to 10 for example correspond to the formulae (16) Rf-SOst-N-CCHj)»— O-(CH₂CH₂O-)p-H (17) Rp-SOj-N-fCHsJm-O-OC-R!

Rs (18) Rp-C Ο—N—(CHj)·»—O (CHiCEi0-),-H

Rs and (19) Rp—C Ο—O (CIIjCH-O—)_D—II wherein R_p, R₄, R_s and m have the meanings given above and p represents an integer having a value of at most 10.

Of especial interest are perfluorinated carboxylic acids, their alkali metal salts or esters of perfluoro-alcohols with aliphatic carboxylic acids. These perfluoro compounds correspond to the formulae (20) F—(CF₂)_n—CO—Ο—X (21) H—(CF₂)_a—CO—Ο—X (22) F—(CF₂)_n—CHz—O—OC—R₅ and (23) H— (CF₂)_n—CHz—O—OC—R₅ wherein X, R_s and n have the meanings given above. Preferably n is 7 or 8.

An especially suitable wetting agent corresponds to the formula (24) ch₂—COOK

FsC—(CF₂)j—SOa— ^CHz- CHs

Wetting agents of Formulae 1 to 10 and 12 to 24 are commercially available and are for example sold by Minnesota Mining and Manufacturing Company as “retypes and by E. I. du Pont de Nemours and Company under the name “Zonyl S.”

The wetting agents to be used in accordance with the invention are employed in concentrations of 0.05 to 5.0 g. per kg. of ready-to-cast solution, preferably in amounts of from 0.2 g. to 1 g. The photographic properties such as sensitivity, gradation and haze are not influenced by the perfluorinated wetting agents.

The wetting agents to be used in accordance with the invention can also be employed together with other known nonperfluorinated surface-active compounds, for example saponin. Gelatine-containing solutions which contain the wetting agents to be used in accordance with the invention are not only suitable for the application of a single layer but especially also for the simultaneous application of several layers according to the cascade casting process, as is described in United States patent specification No. 3,005,440. Instead of a simultaneous applica5 tion of several layers it is also possible to manufacture a multi-layer laminate by applying one layer after the other onto the same support, either by using a wet-ondry process or by using a wet-on-wet process.

The wetting agents of the type “FC” or “Zonyl S” used10 in the examples which follow are products of Minnesota Mining and Manufacturing Company and E. I. du Pont de Nemours and Company, respectively.

The following examples illustrate the invention:—

EXAMPLE 1

A photographic silver halide-gelatine emulsion containing 25 g. of silver as silver bromide with 2.5 mol percent of silver iodide and 40 g. of gelatine per kg. of emulsion is cast on a substrated transparent cellulose triacetate substrate, with the commercial product “FC 128”, of probable Formula 24 being added as the wetting agent in various amounts within the range of 0.05 g. to 3.0 g. per kg. of ready-to-cast solution. All layers are free from faults and are uniform. A sensitometric examination shows no differences in sensitivity, gradation or haze.

Similar results are obtained with the commercial products “FC 126 (anionic), FC 95 (anionic), FC 98 (anionic), FC 170 (non-ionic), FC 176 (non-ionic) and “Zonyl S 13” (phosphoric acid esters).

EXAMPLE 2

A photographic silver halide gelatine emulsion and an aqueous gelatine solution as a protective layer are simultaneously applied to a transparent cellulose triacetate substrate with the aid of the cascade casting ³⁵ process, as described in United States patent specification No. 3,005,400. The silver halide-gelatine emulsion contains 0.5 g. of “FC 128” of probable Formula 24, and the gelatine solution contains 2.0 g. of “FC 128” per kg. of casting mixture. The resulting product is free ⁴⁰ from streaks and other casting faults.

EXAMPLE 3

A silver bromide-iodide emulsion is manufactured which contains 30 g. of gelatine, 13 g. of silver as silver 45 bromide with 2.5 mol percent of silver iodide and 2.4 g. of a blue-green dyestuff according to British patent specification No. 1,042,300, in 1000 g. of solution. The silver halide is sensitised towards red light in the usual manner.

One half of the emulsion is cast on a transparent cellulose triacetate substrate, with 0.3 g. of an alkylnaphthalenesulphonate per kg. of casting solution being used as the wetting agent. The other half of the emulsion is cast on the same support, with the addition of 0.3 55 g. of “FC 128” of probable Formula 24. Both layers are exposed behind a grey wedge and are developed in a p-methylaminophenolsulphate-hydroquinone developer.

The following results are obtained:

Sensitivity

Wetting agent Haze rel. log. units Gradation

With aikylnapthaienesulphonate.— 0.02 3.22 0.58

With “FC 128”.______________- 0.02 3.22 0.58

Furthermore, a 1 metre long piece of both cast films ⁶⁵ is fixed without exposure, cut into 35 mm. wide strips, and the colour density of these strips measured at ihtervals of 6 mm. at a time. The mean value of- the colour density and the standard deviation are calculated for both cast films from the measured values: Mean value of . the colour Standard

Wetting agent density deviation

With alkylnaphthalenesulphate.....____ 2.00 0.324

With “FC 128”_________ 1.98 0.07g

------------------------—-----3,666,478

From this it can be seen that the layer containing “FC 128” is much more uniform than the layer containing alkylnaphthalenesulphonate.

Explanation

Standard deviation q *Tm)²^S=\ n—1 x_m=mean value x=measured values n=number of measured values

EXAMPLE 4

The following layers are successively applied to a transparent polyethylene terephthalate substrate:

(1) A silver halide-gelatine emulsion sensitised to red light, containing a blue-green image dyestuff according to British patent specification No. 1,042,300.

(2) A gelatine layer.

(3) A silver halide-gelatine emulsion sensitised towards green light, containing a purple image dyestuff according to British patent specification No. 914,876.

(4) A gelatine layer.

(5) An unsensitised silver halide-gelatine emulsion containing a yellow image dyestuff according to British patent specification No. 1,094,956.

0.035% of “FC 128” of probable Formula 24 are in each case added as the wetting agent to the ready-to-cast solutions.

In a comparison experiment, the same solutions using 0.035% of an alkylnaphthalenesulphonate were cast.

Samples of both materials are fixed, washed and dried. All colour densities lie between 2.5 and 2.8.

Two other samples of these materials are hazed by homogeneous exposure, developed in p-methylaminophenolsulphatehydroquinone developer, soaked, bleached in a colour bleaching bath, soaked, freed of excess silver in a bleach fixing bath, soaked and dried. A strip of 1 metre length and 35 mm. width was cut from each of these two samples and the colour densities were measured at intervals of 6 mm. The following values are thus obtained:

Standard deviations of the

Mean values of the analytical colour densities analytical colour densities in ENDT-units X 10-³

<td> Wetting agent</td><td> Yellow</td><td> Purple</td><td> Bluegree</td><td> Yellow</td><td> Purple</td><td> Bluegreen</td>

<td> Alkylnaphthalenesulphonate______</td><td> 1.20</td><td> 0.97</td><td> 1.17</td><td> 88</td><td> 19</td><td> IOS</td>

<td> “FC 128”.......</td><td> 1.08</td><td> 1.02</td><td> 1.24</td><td> 32</td><td> 21</td><td> 26</td>

It can be seen from this table that after photographic processing the material containing “FC 128” is again more uniform than the material containing alkylnaphthalenesulphonate.