DE1173795B - Photographic material - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

GERMAN

PATENT OFFICE

EDITORIAL

Boarding school Class: G 03 c

German KL: 57 b-8/01

Number: 1173 795

File number: E 23046IX a / 57 b

Filing date: June 16, 1962

Opening day: July 9, 1964

The invention relates to a photographic material having a silver salt emulsion layer suitable for the silver salt contains a special binder substance.

Photographic emulsions are typically made by suspending one or more silver salts prepared in an aqueous gelatin solution. The suspension can also contain sensitizers, antifoggants, Peptizers and the like can be added. It has now been shown that the gelatin often can adversely affect the dimensional stability of the photographic material. This is especially the case when low strength film supports, e.g. B. made of polyesters or polycarbonates, or if unsized paper or paper glued with waterglass is used, in which the aqueous emulsion can easily penetrate. It is therefore already known to add substances to gelatine, to eliminate their harmful side effects. However, it has been shown that this Mixtures are difficult to process because they are difficult or even impossible to process after drying do not allow to redisperse.

The invention was therefore based on the object to provide a photographic material whose Silver salt emulsion layer must be free from the adverse side effects caused by gelatin should. In particular, a material should be excellent in dimensional stability and flexibility by means of a An emulsion that is easy to process and adheres well to the carrier can be created.

This object has been achieved by developing a photographic material which thereby is characterized in that in the silver salt emulsion layer 20 to 100% of the binder, e.g. B. gelatin, for the silver salt, as dry weight, from a water-soluble ammonium or alkali salt one There are alkyl acrylate-acrylic acid copolymer containing 50 to 90 mol percent of alkyl acrylate groups Contains alkyl radicals with 1 to 10 carbon atoms and 50 to 10 mol percent acrylic acid.

It has been shown that the water-soluble ammonium or alkali salts of the copolymers of Alkyl acrylate-acrylic acid copolymers are not only suitable carriers for the photosensitive Are silver grains, but that they also have good dimensional stability of the photographic material guarantee and do not have the property of becoming detached from the carrier material. Really important is that the copolymers even with high moisture the stability of the carrier material not affect. Be the water-soluble photographic material

Applicant:

Eastman Kodak Company, Rochester, NY
(V. St. A.)

Representative:

Dr.-Ing. W. Wolff and H. Bartels, patent attorneys, Stuttgart 1, Lange Str. 51

Named as inventor:

Robert Charles Houck t,

Donald Arthur Smith,

Joseph Samuel Yudelson, Rochester, N.Y.

(V. St. A.)

Claimed priority:

V. St. v. America 19 September 1961

(139 313)

Ammonium or alkali salts of the alkyl acrylate-acrylic acid copolymers used in a photographic gelatin silver salt emulsion as a topcoat is applied to a paper, or the salts act as a layer between the paper and the emulsion used, the emulsion does not penetrate the paper, but remains on its surface, too if the paper carrier is an otherwise easily penetrable paper.

The copolymers required to produce the material of the invention are obtained by copolymerization a mixture of an alkyl acrylate and acrylic acid. The water soluble polymeric salts make up 20 to 100% of those used in aqueous solution as binders for the silver salt Gelatin polymer binder. Are acrylates with alkyl groups with 6 to 10 carbon atoms

5 ″ is used, better water solubility is obtained if the proportion of acrylic acid in the polymer is at least about 30 ^fl / o.

409 629/303

The copolymer salts used for the production of the photographic material according to the invention clearly differ in their composition from the polymeric acrylic compounds, as they are from the German Auslegeschrift 1 013 166 for the production of photographic Layers of synthetic polymeric hydrosols are known. To produce the well-known polymeric hydrosols are used as polymerization components, alkyl acrylates and esters of acrylic acid and methacrylic acid are used. Apart from the fact that the known polymers do not have any salt groups have, they are not used for making a silver salt emulsion, but for making polymeric hydrosols used in the aromatic compounds involved in the photographic process, such as B. color couplers are to be installed.

The copolymers used to make the photographic material of the invention can be produced by various processes. For example, they can be more appropriate in the presence Catalysts can be made by a solution or dough polymerization process. To carrying out the polymerization for the desired period of time, the reaction product be precipitated by pouring the reaction mass into water, whereupon the precipitate is washed and is redissolved in water containing ammonium hydroxide. The copolymer can be produced by emulsion polymerization or the like using an acrylic acid content in the specified range whereupon the polymer is converted into the water-soluble ammonium or alkali salt will. The copolymers of alkyl acrylate and acrylic acid can by hydrolysis of a Polyalkyl acrylate, e.g. B. of Polyäthylacrylat, for example under alkaline conditions and under Interrupt the reaction at the appropriate degree of conversion.

The following examples illustrate the preparation of photographic products in accordance with the invention.

example 1

A dimensionally stable polystyrene film is coated with the following layers:

No. 1 Resin-containing subcarrier coating

4% 50:50 iso-normal butyl methacrylate,
25% methanol,

3% butanol,
68% hexane.

No. 2 Nitrate-containing subcarrier coating

2% cellulose nitrate ("CWF" type),
15% methyl cellosolve,
83% methanol.

A third auxiliary carrier layer, which consists of a copolymer of ethyl acrylate, is applied to this and acrylic acid in the ratio 75:25 (not the salt). This polymer is in methanol dissolved to form a stock solution containing 15 percent by weight of the polymer. This stock solution is then used to make the following Mixture:

1% copolymer,
15% methyl cellosolve,
15% water,

25% acetone,
44% methanol.

The polystyrene carrier is then with this solution ίο by means of a drop coating process as Coated auxiliary carrier layer. A photographic print is then applied to the polystyrene film support obtained Emulsion applied with the following composition:

4.25 parts by weight of the ammonium salt of the copolymer of ethyl acrylate and acrylic acid, in which the acrylic acid is 25 mole percent,

0.75 parts by weight gelatin,

5.0 parts by weight of silver salt,
90.0 parts by weight of water.

Coatings are also carried out using this emulsion at 4% (based on the polymer weight) of bis (2,3-epoxypropoxyethyl) ether therein. The emulsion coatings are Aged for 2 days at 50% relative humidity and 24 ° C. The adhesive strength of the emulsion coatings on the film carrier is excellent, both after application and after processing in the developer, Fixing and water bath.

Example 2

1870 g of a washed, sulfur-sensitized fine grain silver bromoiodide emulsion which Contains 0.98 mol of silver salt and 49 g of gelatin per mol of silver halide, 4.21 kg of a 6.84% strength Solution of the ammonium salt of a copolymer of ethyl acrylate and acrylic acid (acrylic acid is 20 percent by weight of the polymer) and mixed with 8.84 g of bis (2,3-epoxypropoxyäthyi) ether hardener. This mixture is applied to a polystyrene film support and dried with warm air. The film is aged for 10 months at 21 ° C and 50% relative humidity and then for V25 seconds exposed through a step wedge to light with a color temperature of 3000 ° K for 8 minutes in a developer, fixed in a normal fixing bath for 10 minutes, and washed with water. The following results were obtained:

Sensitivity *) 0.97

Gamma 1.18

Veil 0.23

*) Log of the exposure at a density of 0.3 above a thick fog.

An emulsion similar to the above-mentioned emulsion is prepared except that 4.21 kg of one 6.84% gelatin solution and 1.75 g formaldehyde instead of the salt of the acrylic acid-ethyl acrylate copolymer and bis (2,3-epoxypropoxyethyl) ether can be used. The two emulsions are each applied to film bases made of polystyrene, polyethylene terephthalate and Cellulose triacetate exist. The following dimensional properties were observed:

5 Film carrier Humidity amplitude
(20 to 70% relative
Humidity)
raw 6th 35 mm moisture
Deformation amplitude
(10 to 70% relative
Humidity)
raw Emulsion carrier Polystyrene
Polystyrene
Polyethylene
terephthalate
Polyethylene
terephthalate
Cellulose triacetate
Cellulose triacetate 0.009%
0.065%
0.026%
0.075%
0.170%
0.228% 0.254 mm (0.01 seconds)
4.57 mm (0.18 seconds)
0.0 mm (0.00 seconds)
3.30 mm (0.13 seconds)
0.0 mm (0.00 seconds)
6.35 mm (0.25 seconds) Salt of an ethyl acrylate acrylic acid
Mixed polymer and gelatin
gelatin
Salt of an ethyl acrylate acrylic acid
Mixed polymer and gelatin
gelatin
Salt of an ethyl acrylate acrylic acid
Mixed polymer and gelatin
gelatin

Example 3

A silver bromoiodide gelatin emulsion, which weighs 3.75 kg and contains 203 g of gelatin per mole of silver salt (92% water content), is mixed with 5 kg of an 8.74% strength aqueous solution of an ammonium salt of ethyl acrylate-acrylic acid polymer (80:20 ), 1.71 distilled water and 37 mg of a 10% strength aqueous sodium sulfite solution, 18 mg of a 15% strength aqueous formaldehyde solution and 250 ml of a 5% strength solution of butanediol bis-glycidyl ether in methanol. This photographic emulsion is applied at the speed of 148.60 m ² per mole of silver salt onto an unsized, inexpensive paper support, e.g. B. a commercially available typewriter paper weighing 4.53 kg, applied and dried. A sample of this paper is exposed through a microfilm negative at 22x magnification. The exposed paper is developed in a developer for 60 seconds, fixed and dried. A dimensionally stable, photographic paper projection print with good properties is obtained. +5

Example 4

A silver bromoiodide gelatin photographic emulsion as described in the previous example is used. 18.5 ml of p-tert-octylphenoxyethoxyethymodium sulfate in aqueous solution are added as a coating aid per liter of photographic emulsion. A solution is prepared that contains 16 kg of 8.74% of the ammonium salt of ethyl acrylate-acrylic acid copolymer (80:20), 160 ml of 10% sodium sulfite, 223 g of colloidal silica ("Syloid") in 3 l of distilled water, 633 ml of butanediol bis-glycidyl ether and 300 ml of a 15% aqueous formaldehyde solution. The emulsion and the solution are simultaneously applied to a support made of ordinary paper by the method described in U.S. Pat. No. 2,761,791, the solution being the closest to the support. The silver halide emulsion has a coverage of about 0.0243 kg / dm ² and the solution has a coverage of about 0.0733 kg / dm ² . A highly sensitive paper is obtained in that the photosensitive layer is only retained on the surface of the paper.

Example 5

A series of coatings of silver salt gelatin emulsions which contain ethyl acrylate / acrylic acid mixed polymer salt in various proportions are applied to a partially acetylated paper backing of the type described in U.S. Patent Application Ser. No. 755 418 described type applied. The coatings are applied to paper at a rate of 0.0431 g / dm ^2. The compositions of the carrier substance in the emulsion mixtures concerned are as follows: 100% gelatin, 80% gelatin - 20% ammonium salt of ethyl acrylate-acrylic acid, 60% gelatin - 40% ammonium salt of ethyl acrylate-acrylic acid copolymer, 40% gelatin - 60% of the polymer acid and 20% gelatin - 80% of the polymer salt. Samples of these coatings are developed with a developer (60 seconds at 20 ° C); 1% acetic acid breaker bath (15 seconds); Fixer bath (5 minutes); Wash in running water for 10 minutes and dry. The dried samples are passed through a Paragon "Revolute Rocket" extractor at a speed of 3.65 m per minute. The hood temperature is 99 ° C and the room humidity is 50% relative humidity. The samples are assessed for deformation after the first, fifth and tenth pass of the samples through the fume cupboard.

At each stage, the sample using only the gelatin vehicle shows the strongest Deformation which becomes less and less severe when the proportion of ammonium salt of ethyl acrylate-acrylic acid polymer increases. The samples with the higher proportions of the polymer salt are located after exiting the take-off device smooth.

In the production of photosensitive paper from emulsions, which are an essential part of the Carrier substance is a water-soluble salt of an alkyl acrylate-acrylic acid copolymer contain or if this salt immediately before application

the photosensitive emulsion is applied to the paper several advantages are obtained:

1. When emulsions containing the polymer salt are applied to an unsized paper backing the aqueous emulsion tends to stay on top of the paper, without wanting to pass through the carrier and thereby causing the paper to curl caused. This is more pronounced with proportions of the polymer salt that are at least equal the gelatin content.

2. Incorporation of the polymer salt into silver salt gelatin emulsions according to the invention reduces the tendency of the layers produced therefrom to curl in the wet state Coating machine or after drying. This decrease in curl is special clear if the proportion of the polymer salt is at least equal to the gelatin proportion is.

3. The addition of polymer salt gives a high coating ability because it is possible to lower To coat emulsion liquid per unit area, with thinner coatings obtained as if only gelatin is used as the carrier. This attribute is particularly advantageous at high coating speeds.

4. Silver salt gelatin emulsions containing polymer salt show a much higher rate in the case of thiosulphate removal as emulsions in which only gelatine is used as a carrier is used.

5. The presence of alkyl acrylate-acrylic acid copolymer salt results in a decrease in the Stickiness.

6. Silver salt emulsions containing the salt of alkyl acrylate-acrylic acid polymer contain considerably higher physical strength when applied to light paper than similar coatings in which only gelatin is used.

7. The use of a layer of such a water-soluble salt of alkyl acrylate-acrylic acid copolymer between the emulsion layer and the paper support is particularly useful in the case of papers for the Surface application methods are determined, with very low proportions of solution on the surface be applied.

All examples relate to alkyl acrylates with alkyl groups with 1 to 10 carbon atoms. It will also mixtures of gelatin and acrylate-acrylic acid copolymer salts Used as a solvent carrier for silver salt emulsions, with a hardener, in particular of the epoxy type, also being added to the mixture is recorded. For example, sometimes in the emulsion mixtures the use of up to 10%, based on the polymer weight, of an epoxy hardener such as bis (2,3-epoxypropoxyethyl) ether he wishes.

Claims (5)

Patent claims: 1. Photographic material, consisting of a support and at least one photographic material Process involved layer, which contains a polymeric acrylic compound, thereby characterized in that in the silver salt emulsion layer 20 to 100% of the binder for the silver salt, as dry weight, of a water-soluble ammonium or alkali salt Alkyl acrylate - acrylic acid copolymer consists of 50 to 90 mol percent of alkyl acrylate groups with alkyl radicals with 1 to 10 carbon atoms and 50 to 10 mol percent acrylic acid groups contains. 2. Photographic material according to claim 1, characterized in that the binder is a Contains water-soluble ammonium or alkali salt of an ethyl acrylate-acrylic acid copolymer. 3. Photographic material according to either of Claims 1 and 2, characterized in that about 85% of the binder consists of an ammonium salt of an ethyl acrylate-acrylic acid copolymer which contains about 75 mole percent ethyl acrylate and 25 mole percent acrylic acid. 4. Photographic material according to any one of claims 1 to 3, characterized in that the silver salt emulsion layer up to 10%, based on the weight of the copolymer an epoxy hardener. 5. Photographic material according to claim 1, characterized in that it is between a Paper support and the silver salt emulsion layer a layer of a water-soluble salt Contains alkyl acrylate-acrylic acid copolymer. Considered publications:
German interpretative document No. 1 013 166. 409 629B03 6.64 © Bundesdruckerei Berlin