US2835578A - Light-sensitive photographic paper containing an ethenone material - Google Patents

Description

y 1958 T. DAVIS ET AL, 2,835,578

LIGHT-SENSITIVE PHOTOGRAPHIC PAPER CONTAINING AN ETHENONE MATERIAL Filed Oct. 31, 1955 PH 0 TOG'RAPH/C SILVER HA L IDE EMULSION BA R Y TA COAT/N6 GELATIN AND KETENE D/MER PHOTOGRAPH/C SILVER HA LIDE EMULSION Figz PHOTOGRAPH/C GELATINO- SILVER HAL/DE EMULSION CONTAINING KETENE DIMER \GELATIN AND g- 3 KETENE DIMER GELATIN AND KETENE DIMER Kearney]? Eriffin TI; olpas L..D avis William Driscoll INVEN TORY OS MQh y n-Ton 17$ United States Patent LIGHT-SENSITIVE PHOTOGRAPHIC PAPER CONTAINING AN ETHENONE MATERIAL Thomas L. Davis, William T. Driscoll, and Kearney P. Griflin, Rochester, N. Y., assignors to Eastman Kodak glompany, Rochester, N. Y., a corporation of New ersey Application October 31, 1955, Serial No. 543,892 4 Claims. (Cl. 96-85) This invention concerns the preparation of photographic paper, more particularly a photographic paper having a surface that is resistant to the penetration of water and processing chemicals.

In the preparation of photographic paper, it is customary to coat the paper with a baryta coating over which is coated a photographic emulsion containing gelatin and light-sensitive silver halide salts. However, in the course of making photographic prints it is necessary to process the photographic paper usually by immersing the paper in baths of processing solutions. Extensive washing is required of these photographic papers after processing to remove excess silver and silver complex salts. Such chemicals, if retained in the paper, impart an objectional color or stain to the prints and affect the permanence of the paper. These conditions are undesirable especially where legal documents are involved.

In order to overcome the necessity for extensive washor in the alternative, staining, various coatings for photographic paper have been suggested. For instance U. S. 2,415,631 issued to Galley teaches the formation of a water resistant photographic paper in which baryta coated paper is coated on both sides of the paper with a melt coating of a low-viscosity butyric acid ester of cellulose. The sensitized emulsion is applied on the baryta coated side of the paper over the butyric acid ester.

For ordinary purposes, complete waterproofing of the paper is not necessary, but it has been desired to provide a paper which would have reduced penetration of processing chemicals and the like, so that the Washing period might be reduced and the permanence of the paper improved.

Various problems are introduced when sizing agents are used on the paper base under a photographic emulsion such as emulsion frill in which the emulsion separates from the paper base particularly during processing. For this reason, many commercial sizes have been found unsuitable for photographic paper. We have discovered that the use of an alkylketene dimer when prepared in a suitable solution can be used to protect photographic paper base from penetration of processing chemicals and the like. When used as a component of a paper sensitizing gelatino-silver halide photographic emulsion, an improved bond between paper and emulsion is obtained, particularly when the paper has been treated with a gelatino-ketene dimer size.

One object of our invention is to-provide a simple and direct method of preparing photographic paper in which the paper support becomes semi-water resistant. Another object of our invention is to provide a photographic paper which tends to restrict penetration into the paper of processing chemicals and the like. A further object is to provide a process for improving the surface characteristices of photographic paper supports. An additional object is to provide a paper sizing material which can be used with a photographic emulsion free from emulsion frill. Another object is to provide a sizing material which reacts with cellulose fibers on the surface ice 2 of the paper and becomes an integral part of the paper. An additional object is to provide a gelatino-photographic emulsion with improved adhesion when coated on a paper support. Other objects of our invention will appear herein.

Ketene dimers have been known in the art for use in treating various compounds. For instance, U. S. Patent 2,171,241, issued August 29, 1939, to Johnson discloses a process of modifying silk fibers by exposing the silk fibers to the action of a ketene dimer. U. S. 2,383,863, issued August 28, 1945, to Hueter teaches a process for preparing ketene dimers. Other disclosures show treatment for rendering textiles, fibers, and the like water repellent in which these materials are treated with higher molecular ethenones or ketenes and subjected to a mild heat treatment.

The use of ketene dimers produced according to the Heuter process and used for producing water resistant paper, when coated with a photographic emulsion, results in emulsion frill during the photographic developing process. Consequently, it would be expected that the use of ketene dimers would not be applicable for photographic purposes.

We have found unexpectedly that we can prepare a sizing solution for photographic applications which is compatible with photographic emulsions and which is free from emulsion frill during photographicprocessing. In our invention, we use an aqueous sizing solution containing from 0.5 to 4%gelatin, and 0.6 to 3% of an alkylketene dimer prepared according to the Heuter process.

Also included in the scope of our invention is the addition of stearoyl hexadecyl ethenone to gelatin coating compositions which may contain other materials. For instance, gelatino-silver halide photographic emulsions, dye containing compositions, and other gelatino coating compositions may have this material added thereto. This addition aids in the bonding of these coatings to previous coatings containing stearoyl hexadecyl ethenone in the event that the emulsion is coated on a support containing stearoyl hexadecyl ethenone. When used on a paper which has not been so sized or over a baryta coating, an improved result is also obtained as compared to gelatinophotographic emulsions without stearoyl hexadecyl ethenone. The emulsion containing stearoyl hexadecyl ethenone fiows onto the paper support with greater facility and results in a more uniform product. From 6 to 35% of the ketene dimer is' incorporated into the emulsion based on the weight of the gelatin in the emulsion.

The attached drawing illustrates photographic papers in accordance with our invention. Figure 1 shows a photographic paper having a baryta coating over the gelatino-ketene dimer size. Figure 2 shows a photographic paper without the baryta coating, with the photographic emulsion coated directly on the gelatino-ketene dimer sized paper. Figure 3 shows a photographic paper coated with a gelatino-silver halide photographic emulsion containing a ketene dimer.

The starting compound used to prepare the ketene dimer may be one of those disclosed by Heuter. However, we prefer to use the ketene dimers in which the starting material is stearic or lauric acid.

Preparation of the ketene dimer dispersion must be carried out under carefully controlled conditions. We have found that the preferred method of preparing a dispersion In preparing photographic paper according to our invention, the paper is sized by immersing it in a solution of gelatin and ketene dimer although the sizing solution may be applied by conventional means such as dip roller, spray coater and the like. Following this operation, the paper is dried and sensitized by coating with a photographic emulsion containing light-sensitive silver halide salts. In some grades of paper the paper is baryta coated and dried at a temperature of from ISO-250 F. followed by coating with a photographic emulsion containing light-sensitive silver halide salts.

In preparing gelatino-silver halide photographic emulsions containing stearoyl hexadecyl ethanone, the ketene dimer may be dispersed in water as shown above for preparing a paper size. It may also be dispersed by heating in methanol, ethanol or the like to a temperature of from 115 to 140 F., preferably to about 120 F. and then added directly to the gelatino-photographic emulsion which is usually at a temperature of above about 90 F.

The paper coating composition containing stearoyl hexadecyl ethenone is maintained at a temperature of from 85-125 F. during the coating operation to obtain optimum results in coating and stability of the disper- $1011.

The following examples illustrate our invention but are not intended to limit it in any way.

Example 1 A gelatino-silver halide photographic emulsion was prepared for sensitizing photographic paper base. Stearoyl hexadecyl ethenone equal to 22.5% of the weight of the gelatin in the emulsion was dispersed by heating 140 F. in 40% of its weight of methanol. This dispersion was added hot, directly to the photographic emulsion which was then coated in the normal manner on supports sized with compositions containing stearoyl hexadecyl ethenone. Other amounts of stearoyl hexadecyl ethenone, including 34.75, 22.5, 12.25 and 6.1% based on the weight of gelatin, were also used. Good bonding was obtained between the support and the emulsion in all of the above applications.

Example 2 A 100% beaten rag fiber sheet was made containing rosin size, aluminum chloride, load (TiO melamine formaldehyde and heater gelatin. The paper was surface sized with a two bath operation containing stearoyl hexadecyl ethenone and 0.5% gelatin in the first pan and 1% gelatin in the second pan. Normal drying and calendering conditions were observed throughout the making.

Example 3 A 100% beaten rag fiber sheet was made containing aluminum chloride, load (TiO melamine formaldehyde, and beater gelatin. The paper was surface sized with stearoyl hexadecyl ethenone and gelatin as shown in Example 2.

Example4 The same type of 100% beaten rag fiber sheet, chemicals and surface sizing as described under Example 3 were used in preparing photographic paper base which was coated with a baryta-gelatin coating.

Example 5 A 100% beaten rag fiber sheet was made containing rosin size, aluminum chloride, load (TiO melamine formaldehyde, and beater gelatin. The paper was surface sized with a one bath operation containing stearoyl hexadecyl ethenone and 2 to 4% gelatin.

Example 6 A 100% wood base sheet was made containing A-size, aluminium chloride, melamine formaldehyde, starch, and beater gelatin. The paper was surface sized with a one bath operation containing stearoyl hexadecyl ethenone and 2 to 4% gelatin.

Example 7 A beaten wood base sheet was made containing A-size, aluminum chloride, load (TiO melamine formaldehyde, starch, and beater gelatin. The paper was surface sized with a one bath operation containing stearoyl hexadecyl ethenone and 2 to 4% gelatin.

Example 8 A 100% beaten wood base sheet was made containing aluminium chloride, load (TiO melamine formaldehyde, starch, and heater gelatin, but no A-size. The paper was surface sized with a one bath operation containing stearoyl hexadecyl ethenone and 2 to 4% gelatin.

Example 9 A 100% wood base sheet was made containing aluminum chloride and melamine formaldehyde. The paper was sized by various methods with a solution of stearoyl hexadecyl ethenone and /z% gelatin. The hopper, suction slide hopper, nip, and spray methods were all comparable to the size press method previously described.

Example 10 A 100% wood base sheet was made containing A-size, hydrochloric .acid, melamine formaldehyde, beater gelatin, and starch. The paper was sized with a solution of stearoyl hexadecyl ethenone and /2 gelatin.

Samples of paper prepared according to the above nine examples were coated with light-sensitive silver halide emulsions and processed in photographic developing and fixing solutions. No emulsion frill was present. Similar samples sized with aqueous stearoyl hexadecyl ethe none alone showed quite poor emulsion adhesion. The processed papers sized with stearoyl hexadecyl ethenone and gelatin showed 4050% less residual chemicals under similar processing conditions than paper base which had not been sized with the stearoyl hexadecyl ethenone gelatin mixture. This reduction in residual chemicals indicates that washing may be accomplished in a much shorter time. The finished print on paper sized with the gelatin-stearoyl hexadecyl ethenone sizing had much less tendency to stain than a print on regular stock which did not contain the stearoyl hexadecyl ethenone-gelatin sizing.

The stearoyl hexadecyl ethenone-gelatin sizing may be applied to rag or wood fiber by surface sizing, nip sizing or spray sizing. It may also be applied to one side of the sheet to improve the coatability of subsequent applications such as baryta and the like.

In photographic processing of prints one of the time consuming steps normally present is that of washing the photographic prints to remove residual chemicals such as silver and silver complexes which if permitted to remain will result in stains on the print. We have discovered a size which may be used to coat photographic paper to render it resistant to water and to processing chemicals and which, therefore, permits processing with a shorter washing time than was previously possible and yet obtain a suitable photographic print free from residual chemicals which might produce stain and the like. In addition, our size has the advantage over commercially available sizes in that it is free from emulsion frill during photographic processing.

Moreover, this sizing material provides a highly improved surface on which for some purposes may be deposited a photographic emulsion directly without requiring a baryta coating placed over the sized paper. Consequently, the use of our sizing material will serve to improve photographic papers as will as save time and money for the photographic processors who will not now need to spend as much time in washing the photographic prints.

This ketene dimer is compatible with photographic emulsions and. free from photographic activity. It not only can be used to size photographic paper base, but also can be used as a component in photographic emul- 5 sions. When used in a photographic emulsion it enhances adhesion to the paper base and also improves the fiowability of the emulsion onto the paper support and results in more uniform photographic paper.

We claim:

1. A photographic paper containing a coating from an aqueous solution comprising 0.5 to 4% gelatin and 0.6 to 3% of an ethenone material having the following formula in which R is an alkyl group containing from 12 to 18 carbon atoms, coating with a mixture containing gelatin and baryta, and coating with a photographic emulsion containing light sensitive silver halide salts.

3. A light sensitive gelatino-silved halide emulsion containing 635% of stearoyl hexadecyl ethenone based on the weight of the gelatin in the emulsion.

4. A photographic paper containing a stearoyl hexa decyl ethenone-gelatin size in which from 0.15 to 3.0% of the dry weight of the uncoated paper is the ethenone and from 0.15 to 3.0% the dry weight of the uncoated paper is gelatin and having a light sensitive gelatino silver halide emulsion.

References Cited in the file of this patent UNITED STATES PATENTS 2,334,215 Nadeau et a1. Nov. 16, 1943 2,360,216 Fillius' Oct. 10, 1944 2,606,832 Alles et a1. Aug. 12, 1952 2,627,477 Downey Feb. 3, 1953

Claims (1)

1. A PHOTOGRAPHIC PAPER CONTAINING A COATING FORM AN AQUEOUS COMPRISING 0.5 TO 4% GELATIN AND 0.6 TO 3% OF AN ETHEONE MATERIAL HAVING THE FOLLOWING FORMULA

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