US 3666478 A
Description (OCR text may contain errors)
Ufli id States Patent fice US. Cl. 96-1145 3 Claims ABSTRACT OF THE DISCLOSURE Photographic material, preferably for the silver dyestutf 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.
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, intermediate 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 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, sensitisers, coupling agents and dyestutfs. Furthermore they must improve the physical properties of the casting solutions'to a sufiicient 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) and foam (small bubbles), and which adhere well to the substrate. At the present time especially high demands are madeof such surface-active compounds since thinner layers and higher casting speeds are constantlybeing adopted, with a further aim being to cast layers without waiting for the drying of the previouslypcast layers. In particular,'the manufacture of uniform layers for the silver dyestuff bleaching process presents difiiculties,
since the/casting solutions contain water-soluble azo dyestuffs which undergo mutual interactions with the gelatine and hence unfavourably influence the flow properties of the casting solutions.
The present invention is based on the observation that perfluorinated aliphatic compounds of non-ionic or anioniccharacter can advantagesously be employed as wetting agents in photographic, gelatine-containing, casting solutions, with a much better uniformity. of the applied 3,666,478 Patented May 30,1972
layers being attainable than is possible with the wetting agents usually employed in photographic processes. Thewherein R 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 perlluoro 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 w-H, in the fluorinc-containing residue. ISuch compounds are also called w-H-perfluorinated compounds.
Anionic or anion-active perfluoro compounds for example correspond to the formulae Bra-C O-III-Ih-C OOX R: and above all R2 R represents an alkyl residue which is perfluorinated in the manner indicated, R represents an alkylene residue, R 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 R represents an alkyl residue which is perfiuorinated in the manner indicated, R and R each represents a hydrogen atom or an alkyl residue and R, represents an alkyl residue. a
= The alkyl residues in Formulae 3 to 9 also rufther substituted, for examplebyiurther. functional groups;
Preferably, R represents a residue of formula 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 wherein R R R and m have the meanings given above and 2 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 wherein X, R and n have Preferably n is 7 or 8.
An especially suitable wetting agent corresponds to the formula the meanings given above.
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 PC- types and by I. du Pont de Nemours and Company under the name ZonylS.
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 .nonperfiuorinated surface-active compounds, for example saponin. Gelatine-containing solutions which contain the wetting agents to be used in accordancewith the invention are not only suitable for the application of a single layer but especially also fonthe simultaneotis applicit- -tion 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 application of several layers it is also possible to manufacture a muiti-layer laminate by applying one layer after the other onto the same support, either by usinga wet-ondry process or by using a wet-on-wet process. I v The wetting agents of the type PC or Zonyl-S usedin the examples which follow are products of- Minnesota Mining and Manufacturing Company and E. I.';du Pont de Nemours and Company, respectively. 1 j 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 1281 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 PC 126 (anionic), FC (anionic), FC 98 (anionic), FC (non-ionic), PC 176 (non-ionic) "and Zonyl S 13 (phosphoric acid esters).
EXAMPLE 2 A photographic silver halide gelatine emulsionand an aqueous gelatine solution as a protective layer are simultaneously applied to a transparent cellulose triacetate substrate with the aid of the cascade casting process, as described in United States patent specification No. 3,005,400. The silver halide-gelatine emulsion contains 0.5 g. of PC 128 of probable Formula 24, and the gelatine solution contains 2.0 g. of PC 128. per kg. of casting mixture. The resulting product is free from streaks and other casting faults.
EXAMPLE 3 A silver bromide-iodide emulsion is manufactured which contains 30 g. of gclatine, 13 g. of silver as silver bromide with 2.5 mol percent of silver iodide and 2.4 g. of a blue-green dyestulf according to British "patent specification No. 1,042,300, in 1000 g. of"solution.The silver halide is sensitised towards red "light in the'nsual manner.
One half of the emulsion is cast on a transparent cellulose triacetate substrate, with 0.3 g.v 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 g. of PC 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:
' I Sensitivity Wetting agent Haze rel. log. units Gradetion With alkylnapthalenesulphonate O. 02 3. 22 0. 58 With F0 128 0. 02 3. 22 0. 58
Furthermore, a 1 metre long piece of both cast films is fixed without exposure, cutinto 35 mm. wide strips, and the colour density of these strips measured at intervals of 6' mm. at a time. The mean value of the colour density and the standard deviation are calculated With FG 128 From this it can be seen that the layer containing PC 128 is much more uniform than the layer containing alkylnaphthalenesulphonate.
Explanation Standard deviation x =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 dyestuiT according to British patent specification No. 914,876.
(4) A gelatine layer.
(5) An unsensitised silver halide-gelatine emulsion containing a yellow image dyestuif according to British patent specification No. 1,094,956.
0.035% of PC 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 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.
1. Photographic material which comprises at least one gelatine-containing layer that contains as a wetting agent a water-soluble surface active, aliphatic perfluorosulfonic acid derivative of the formula in which R, is a perfiuorinated alkyl group containing 3 to 9 carbon atoms R is an alkylene residue containing from 1 to 6 carbon atoms R is hydrogen, methyl or ethyl and X is hydrogen or an alkali metal atom.
2. Photographic material as claimed in claim 1, wherein the gelatine-containing layer contains a water-soluble azo dyestutf as well as the perfluoro compound.
3. Photographic material as claimed in claim 2, wherein the perfluoro compound corresponds to the formula References Cited UNITED STATES PATENTS 2,732,398 1/1956 Brice et al. 25271 2,937,098 5/1960 Geen 26029.2 3,415,649 12/1968 Nishio et a1. 96114.5 3,514,293 5/1970 Knox 961l4.5 3,516,835 6/1970 Mackey et al. 96114.5
OTHER REFERENCES Surface Active Materials From Perfluorocarboxylic and Perfluorosulfonic Acids, R. A. Guenthner et al., Industrial and Engineering Chemistry, Product Research and Development, vol. 1, No. 3, pp. -169.
JOHN T. GOOLKASIAN, Primary Examiner G. W. MOXON II, Assistant Examiner US. Cl. X.R. 96-94; 106-135 ag UNI ED STATES PATENT OFFICE CERTIFICATE 9F CORRECTION Patent No. 3,666, L78 Dated May 30, 1972 Inventor(s) Margit Groh et 8.1
It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:
Column 1, line 5, delete 'CIBA Limited" and substitute CIBA-GEIGY AG Signed and sealed this 23rd day of April 1971+.
MARSHALL DANN Commissioner of Patents EDWARD DLFLETCHERJR. G. Atesting Officer