CH625064A5 - Process for producing thermographic and photothermographic recording material - Google Patents

Description

The invention has for its object to provide thermographic and photothermographic recording material using a new class of silver compounds with high sensitivity and improved shelf life, which is easier to produce. This object is achieved by the invention

The invention thus relates to a method for producing thermographic or photothermographic recording material using silver salt complexes with an overall stability constant of the complexing agent of 4.50 to 10.00.

A brief introduction to complex chemistry is required to explain the invention.

Complexes are formed from at least two components if each of these components can exist as such under certain chemical conditions, for example in solution. The complex contains the components without chemical modification and the complex can be isolated. The complex of pyridine and silver nitrate is discussed below to explain these phenomena. Pyridine has a high electron density on the ring nitrogen, which enables it to be attached to ions or compounds with areas of positive charge. In solution with silver nitrate, this accumulation takes place as follows:

N0 ^

O

This complex can be isolated from the solution. It can be seen that the complexing pyridine ligand has not undergone any chemical modification, for example through loss of a hydrogen atom or opening of a bond. As long as a significant amount of a complex is formed by combining a silver salt and a complexing agent with a particular tendency to form complexes for silver ions, the combination of silver salt is and complexing agents

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usable to achieve the object of the invention. It is known that certain complexing agents form both salts and complexes with the central atom. However, for the purposes of the invention, it is generally required that at least an isolatable amount of the complex be formed. If, for example, imidazole is used as the complexing agent, both the silver salt of the formula (A) given below and the silver complex (B) are isolated from the solution.

(A)

C.

Ag ">

(B)

©

NO

©

The stability of coordination compounds depends on the charge density of the special ions or atoms with which the complexing agents form complexes. In the description, all measured values relate to silver ions. The following equation, known as Irving-Rosotti Equation 30, describes the stability of complexes.

n

(L)

(n - 1)

(2 - n) (L) Kxk2

(S - 1)

K

1 equation I

fi means the mean value of the ligand molecules bound per silver atom,

L is the concentration of free ligands,

Ki the stability constant of the first ligand on the silver ion 40 K2 the stability constant of the second ligand on the silver ion.

The stability constants are determined as follows: For each determination, standard solutions of 0.1 m AgNCh, 0.1 m KOH, 0.625 m KNOa, 1 m HNOa and 0.025 45 m of the ligand are prepared. 2.5 mmol of the ligand are dissolved in 80 ml of the potassium nitrate solution and 3 ml of the 1 M nitric acid solution are added to form the ligand nitrate salt. This solution is diluted with a further amount of 0.625 M potassium nitrate solution to 100 ml and thus a 0.025 50 molar ligand solution is obtained.

15 ml of the ligand solution obtained are placed in a beaker together with 15 ml of the 0.625 m potassium nitrate solution and 10 ml of water. This solution is titrated with 0.1 M potassium hydroxide solution, the pH being measured after the addition of 0.5 ml 55. With these values the stability constants (Ki and K2) can be determined by plotting n / (nl) - (L) against 62-fi) * (L) / (fi-l), the slope giving the value Ki K2 and the section length gives the value for Ki; see. Bjerrum, "Metal Amine Formation in Aqueous Solution", P. 60 Haase and Son, Copenhagen, 1957. After determining Ki and K2, the overall stability constant (ß) can be determined as the sum of log Ki and log K2.

To achieve the object according to the invention, suitable ligands with a total stability constant of 4.5 to 10.0 are useful as ligands for the production of complexes for photothermographic and thermographic recording material, at least one of which is required. The reason why the ß-values are important is easy to understand. The complexes to be used according to the invention must provide a source of metallic silver for the image and must therefore be reducible. With ß values below 4.50, the complex delivers silver that is too light; its shelf life is poor and it is less light-stable than stronger complexes. If the reducing agent (the developer) is heated in the vicinity of these complexes with β values of less than 4.50, these complexes are reduced even if they have not yet been exposed imagewise. The complex must therefore have a ß value of at least 4.50 in order to work satisfactorily. Examples of complexes with a β value of less than 4.50 are the weak rc complexes, such as ethylene or benzene complexes, in which silver ions are bound to rc electrons. If the β value is above 10.0, that is to say if the complex is too strong, the recording material can no longer be readily developed by the action of heat, and stronger reducing agents must be used in the recording material. No image is created because there is no metallic silver available to create the image. \

One of the most important advantages described here is the easy coatability of the emulsions containing the silver complex. For this purpose, at least 90% of the silver within the layer which provides the silver image must be present in the form of a complex when coating in the photothermographic and thermographic recording materials. Preferably at least 95% of the silver should be in complex form. Particularly good results are obtained when virtually all silver is complexed, except for the small amount present in the form of the photographic silver halide for photosensitivity

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The invention therefore essentially provides two recording materials:

1. A thermographic recording material which has at least one layer or coating of a binder, a reducing agent and at least one silver salt, which is complexed by at least one complexing agent with a total stability constant of 4.50 to 10.00 and wherein at least 90% of the total silver salt , are present in the layer in the form of a silver salt complex with the complexing agent;

Z is a photothermographic recording material which has at least one layer or coating of a binder, a reducing agent and at least one silver salt, which is complexed by at least one complexing agent with a total stability constant of 4.50 to 10.00 and wherein at least 50% of the total silver in the layer is in the form of a silver salt complex and at least 90% of the total silver salts, not including photographic silver halide, are in the form of a silver salt complex with the complexing agent, and in which 0.25 to 50 mol% of silver halide, based on the total silver, in there is catalytic proximity to the silver salt complex.

The minimum amount of total silver salt in the recording material that must be in the form of photographic silver halide in order to photothermograph the medium is 0.25 mole percent. This small amount of silver halide would require intense exposure to provide a heat developable image. This lower limit of the silver halide in the photothermographic recording material can be used, for example, for “dry silver process” recording material to be handled in daylight. All mole percent silver values refer to total silver in the recording medium.

There is no functional upper limit to the molar percentage of silver halide that can be used in the photothermographic recording material of the invention. In practice a limit of 50 mole percent silver halide is useful. The preferred range is generally 1 to 15 mole percent silver halide based on total silver in the recording medium.

The silver halide can be arranged in catalytic proximity to the silver salt complex by conventional methods. In general, three methods are available, namely the mechanical mixing of silver halide with the silver source, the treatment of the silver source with halide ions (“halogenation”) (cf. US Pat. No. 3,457,075) or the addition of a heat-developable silver source to pre-formed silver halide grains (see U.S. Patent 3,839,049).

Alternative methods can also be used. For example, a silver salt complex can first be prepared and isolated and then added to the binder - explained below in Example 2. The complex can also be prepared in situ within the binder - explained below in Example 1. Both methods can be carried out well, but different precautionary measures must be taken in each case. When using synthetic resins or polymers with acidic groups and complexing agents with basic nitrogen atoms, the complex must be used in excess, for example, because the complexing agent can form an adduct or salt with the polymer.

Any silver salt can be used to bring the remaining amount of silver source to 100% in the photothermographic or thermographic medium. Once the reduction of the silver complex has started, the other silver salt present is usually catalytically reduced to metallic silver for the image. However, although there may be significant amounts of silver halide in catalytic proximity to the silver salt complex (assuming sufficient physical contact or other physically intimate relationship with the catalytic reduction of the complex metallic silver after the silver halide has been sensitized to development by incident light), this is generally not intended There is more than about 10 mole percent total silver salt that is not in a complexed form or as an uncomplexed silver halide to make it easy to coat. All percentages relate to mole percentages unless otherwise stated. Both inorganic and organic silver salts can be used for the purposes of the invention, provided that an isolatable complex can be formed from the silver salt and the complexing agent. Even poorly soluble silver salts, such as silver bromide or silver iodide, can be used, but with greater difficulty. These salts are very sparingly soluble and their solubility products are lower than 10 ~ 10 in common solvents. It is therefore difficult to form significant amounts of the complex because there are only very small amounts of silver ions in solution. Examples of customary silver salts which can be used according to the invention are silver chloride, behenate, nitrate, nitrite, acetate, carbonate, citrate, phthalate borate, sulfate stearate, oxalate, benzoate, phosphate, -2 ethyl hexanoate and arsenate The table below shows the values for Ki, Kz and ß for certain complexing agents:

Table I

Complexing agent log Ki

IogK2

ß

(NHz) 2 CS (thiourea)

.

_

ß3

= 13.0

P-CH3OC6H4SO3

0.1

-

P-C2H5SC6H4SO3

2.62

1.68

ß4 =

= 6.5

p-G> HsS C6H4SO3

1.67

1.34

ß4 =

= 5.7

2-aminoethyl methyl sulfide

4.17

2.71

p-CöHsSe C6H4SO3

2.63

2.26

ß4 =

= 8.7

m-H2NC «H4SC> 3

1.23

0.90

ß4 =

= 2.4

m- (C6Hs) 2PC «H4S03

8.15

5.95

ß3 =

= 20

As (G> H4S03 - m) 3

5.36

-

Imidazole

3.1

3.9

ß2 = 7.0

2,4-dimethylimidazole

3.4

4.1

ß2 = 7.5

Pyridine

2.0

2.2

ß2 =

= 4.2

2-methyl pyridine

2.3

2.4

ß2 =

= 4.7

2,4-dimethylpyridine

2.5

2.4

ß2 =

= 4.9

ammonia

3.2

3.8

ß2 = 7.0

Ethylamine

3.3

3.8

ß * =

= 7.1

2-aminoethanol

3.1

3.6

ß2 = 6.7

2-aminoethyl phosphate

3.7

3.1

ß2 =

= 6.8

2-aminoethyl sulfate

3.3

3.3

ß2 =

= 6.6

In Table I aminocarboxylic acids are not listed as complexing agents. It was found that these compounds do not form a complex with silver ions in solution, except at extreme silver concentrations, which are unsuitable for complexes for thermographic or photothermographic recording materials. From Inorganic Chemistry, Vol. 4, No. 5.1965, pages 767 to 769, it is known that silver ions form salts with aminoacetic acid. The silver ions therefore do not form complexes with the nitrogen atom of such compounds, such as, for example, ethylenidaminetetraacetic acid, but instead form salts with the carboxyl groups. These compounds are therefore used in the recording materials described in U.S. Patent 3,457,075. Since no complexes but salts form when aminoacetic acid and its derivatives are used, they cannot be used as complexing agents for the purposes of the invention

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A preferred class of complexing agents are imidazole compounds, including polymers with imidazolrin genes, which can bind silver ions in a complex manner.

It has been found that those complexing agents which have a β value for silver ions of 4.50 to 10.00 form complexes with inorganic or organic silver salts which are useful in photothermographic or thermographic recording materials.

If the silver salt complexes are present in a binder together with a reducing agent or developing agent and there is no photosensitive salt which generates catalytically active nuclei for reducing the complex, a thermographic recording material is obtained, that is to say this recording material is developed by using thermal imaging patterns on the shift.

In photothermographic recording material, photosensitive salts, which form catalytically active nuclei to reduce the silver salt complex, must be in catalytic proximity to the complex. A compound is in catalytic proximity to the silver salt complex if its physical relationship within the recording material is such that the silver in the complex compound is reduced. One can speak of “catalytic proximity” if the silver salt complex and the light-sensitive salt are distributed statistically or homogeneously within the same layer, if parts of the silver salt complex have been halogenated or if the complex is present in one layer and the salt is in an adjacent layer. The silver salt complex and salt can also be distributed within different surfaces of the same layer.

If the photosensitivity is generated by partial halogenation of the silver salt complex (by generating photosensitive silver halide nuclei using halide ions), the catalytic proximity can be generated directly by the halogenation.

The type of binder is not critical to the operation of the recording material of the invention. Virtually any polymeric compound of natural or synthetic origin and thermoplastic or thermosetting type can therefore be used as the binder. Specific examples of binders that can be used are polyesters, polyamides, poly- olefins, acrylates, epoxy resins, phenolic resins, vinyl polymers, such as polyvinyl acetate, polyvinyl butyrate, or polyvinyl alcohol, ethyl cellulose, polycarbonates, silanes, siloxanes, polyvinyl pyrrolidone, gelatin, gum arabic and mixtures thereof. For photothermographic recording material, the binder component must generally be transparent or translucent. Although all of the polymers previously studied as binders are useful for the recording material of the invention, it has been found that epoxy resins have a deleterious effect on function.

The preferred binders are soluble either in aqueous medium or in non-aqueous organic solvents. Gelatin and polyvinyl alcohol are generally preferred.

The reducing agent contained in the thermographic or photothermographic recording material of the invention can be any reducing agent for silver ions. The reducing agents in question are known for the technique of dry silver process and photography.

The recording materials according to the invention produced with the silver salt complexes described here are remarkably superior to the known dry silver process recording materials. In particular in the case of two-layer materials, that is to say materials which are constructed in such a way that the silver salt complex is present in one layer and the halogen or the halogen source is present in an adjacent layer

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get an image with finer grain and improved resolution. Surprisingly, the finished image is not in the layer that originally contains the silver salt complex, but most of the image silver is found in the surface of the layer that contains the available halide,

or at the interface of the two layers. Up to 95% of the image silver can be found in these areas. Since the image is contained in such a thin area of the material, that is to say in the surface of the halide-providing layer and the interface between the two layers, the grains usually show a high resolution.

The examples illustrate the invention.

example 1

A silver salt complex in a binder suitable as a coating material is prepared by adding 0.85 g (0.005 mol) of silver nitrate to 1.25 g of phenylmethyl sulfide (β = 5.0) in 5 g of methanol. The mixture is mixed with 15 g of an alkyl monoester of a methyl vinyl ether-maleic acid copolymer (Gantrez ES-435), dissolved in isopropanol, and treated with ultrasound for 5 minutes. The solution is then filtered and applied in a thickness of 0.127 mm to a 0.1 mm thick polyester film and dried at 80 ° C. for 5 minutes. Then the layer with a solution of 20 g (16 volume percent solids) of the alkyl monoester of the methyl vinyl ether-maleic acid copolymer with an additional 2.0 g of a2, a2-bis (6-hydroxy-m-tolyl) mesitol (A0-80 Developer), 1.5 g phthalic acid, 0.1 g tetrachlorophthalic anhydride (TCPAN) and 0.2 ml of a 0.5 molar mercury (II) bromide solution in methanol in a thickness of 0.8 mm. The recording material is then dried at 80 ° C. for 5 minutes. The recording material obtained is exposed through a net template using a carbon arc lamp and heat-developed at 138 ° C. for 40 seconds. An image with a Dmin of 0.13 and Dmax of 0.74 is obtained.

Example 2

16.9 g (0.1 mol) of silver nitrate are dissolved in 50 ml of distilled water, and 13.5 ml (0.204 mol) of aqueous ammonia solution are added. The solution is evaporated and cooled. The resulting white precipitate is dried and kept in the dark.

Furthermore, 16.9 g of silver nitrate are dissolved in 50 ml of distilled water and mixed with 75 ml of an aqueous solution which contains 22.4 g (0.20 mol) of ammonium carbonate. A white precipitate forms, which then goes back into solution. The solution is filtered, evaporated and cooled. The resulting white precipitate is filtered and washed with a small amount of acetone and dried.

1.2 g each of the complexes Ag (NHî) 2N03 (ß about 7.2) obtained in the manner described above are dissolved separately in 15 ml of a mixture of isopropanol and water (40:60) which contains 3% by weight of polyvinyl alcohol. The solutions are applied in a thickness of 0.08 mm to 0.1 mm thick polyester films and dried at 82 ° C. for 7 minutes. Then each coated film is cut into 2 pieces. One half of each coated film is 0.08 mm thick with a 50 percent solution of the alkyl monoester of methyl vinyl ether-maleic acid copolymer (Gantrez ES-435) in isopropanol, diluted with 1 part of methanol and 1 part of 1.1. 2-Trichloroethane, which additionally contains 0.5 ml of a 0.5 molar mercury (II) bromide solution and 0.5 g of hydrochione per 15 g of copolymer solution. The top layer obtained is dried at 82 ° C. for 5 minutes. The sample is exposed through a negative original with a carbon arc lamp for 5 seconds and then heat-developed at 127 ° C. for 3 to 5 seconds. The other half of the •

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simply coated film is coated in a thickness of 0.08 mm with the solution of the monoalkyl ester of the methyl vinyl ether-maleic acid copolymer, which contains 2.0 g of developer A080, 1.5 g of phthalic acid, 0.2 g of tetrachlorophthalic anhydride and 0. Contains 5 ml of a 0.5 molar solution of mercury (II) bromide in methanol per 20 g of the copolymer solution. The coated film is dried at 82 ° C. for 6 minutes. Samples are exposed through a gray wedge with an optical density of 0 to 4 and heat-developed at 127 ° C for 15 seconds. The sample has a yellowish background with a good black image. The finished images of the various simply coated films are identical. This means that the silver salt complex prepared with the two methods described can be used with ammonia.

Example 3 \

0.99 g of subcinimide (ß about 9.4) and 0.852 g (0.005 mol) of silver nitrate are dissolved in 5 ml of completely deionized water together with 15 g of a 10% by weight solution of an acrylamide copolymer (cyanamer P-26). Then the solution is mixed with 0.1 g of 5-sulfosalicylic acid and applied in a thickness of 0.1 mm to a subbed polyester film. The coating is dried at 82 ° C for 8 minutes. This coating is then coated with a solution of 0.4 g of hydroquinone and 0.3 mm of a 0.5 molar mercury (II) bromide solution in 20 g of the 10% acrylamide copolymer solution in a thickness of 0.08 mm and at 10 minutes 71 ° C dried.

_ A sample is exposed through a negative original using a carbon arc lamp and developed for 15 seconds at 127 ° C. An image with a Dmin of 0.11 and a Dm «of 1.7 is obtained.

In this example and in the following two examples, the photographic silver halide emulsion gives the light-sensitive salts which, after the formation of a latent image after exposure, catalytically accelerate the reduction of the silver salt complex. The silver salts therefore have the same effect as an immediately halogenated complex or a complex which would be mixed with a light-sensitive salt. It is only necessary for light-sensitive emulsions that the silver halide is in catalytic proximity to the silver salt complex.

The fact that the silver image is provided by the silver salt complex is demonstrated by making the recording material described above without the silver salt complex. This recording material is then exposed imagewise and heated. There is no visible image. This proves that the silver salt complex is necessary to build up the visible image.

Example 4

A solution of 0.99 g succinimide (ß about 9.4) and 0.852 g silver nitrate in 5 ml deionized water is mixed with 15 g of a 10% by weight aqueous solution of the acrylamide copolymer (Cyanamer P-26). The solution obtained is then mixed with 0.1 g of 5-sulfosalicylic acid and 0.4 g of hydroquinone. This solution is poured in a thickness of 0.127 mm onto a known siler halide emulsion (Eastman Kodak SO-192) and dried at 71 ° C. for 6 minutes. The film is then exposed to 10,000 meter candle seconds in an Eastman Kodak 101 sensitometer (lamp temperature 6000 ° K) and heat developed at 127 ° C for 4 seconds. A Dmj "value of 0.4 and a Dmax value of 1.1 are obtained.

Example 5

Example 4 is repeated, but 0.05 g of mercury (II> acetate is added to the coating solution and development is carried out for 15 seconds. The film has a Dmin value of 0.5 and a Dmax value of 2.5 , a sensitivity of lxl 0 ~ 3 ASA, and a gamma value of 0.92.

Example 6

5 Example 5 is repeated, except that the type C microfilm emulsion from 3M Co. is used as the silver halide emulsion. After development, the film is fixed with Kodak F-5-Fix (see Lange Handbook of Chemistry, 9th edition, p. 1760). The film has the following properties: Dmin 0.11, Dmax 1.2. Sensitivity i.l. ASA, Gammà value 0.75.

Example 7

A silver salt complex is produced as follows: 0.75 g imidazole, 0.75 g silver nitrate and 0.19 g phthalic acid are added to 12 g of a mixture of equal parts by volume of methanol and 1,1,2-i5 trichloroethane and the mixture is stirred in an ultrasonic field Mixture with 12 g of a (25:75) mixture of the copolymer Gantrez ES-335-1 and isopropanol (weight ratio). The mixture is stirred for 20 and then applied to a 0.08 mm thick, titanium dioxide-containing polyester film in a thickness of 0.05 mm and dried at 82 ° C for 7 minutes.

A top layer solution is prepared as follows: 0.25 g of tetrachlorophthalic anhydride, 2.0 g of phthalic acid and 2.0 25 g of developer AO-80 are added to 25 g of a mixture of methanol, butanol, an ethanol-soluble cellulose propionate ester (EASP) and of a cellulose duty rate ester (EASB) soluble in ethanol in a weight ratio of 75: 10: 10: 5. After adding 0.045 g of mercury (II> bromide in 2 ml of Me-30 ethanol and 0.01 g of mercury (II) acetate in 1 ml of methanol, the solution is stirred thoroughly and then coated to a thickness of 0.06 mm Film applied and dried for 5 minutes at 82 ° C. Samples of the film are exposed through a continuous gray wedge of optical density 0 to 4 with 35 a carbon arc lamp and developed for 40 seconds in a fluorocarbon bath at 127 ° C. The images obtained have a Dmjm value of 0.10 and a Dmax of 1.26.

«Example 8

5.0 g of a mixture of equal parts by volume of acetone and methanol are mixed with 1.2 g of 2-ethylimidazole, 1.0 g of silver nitrate and 0.3 g of tetrachlorophthalic anhydride (TCPAN) and stirred until dissolved. The solution is then treated with a 45% by weight solution of the copolymer used in Example 1 (Gantrez 435) diluted to 25.0 g in a mixture of equal parts of isopropanol and methanol. The solution obtained is applied to a support in a thickness of 0.07 mm and dried at 82 ° C. for 6 minutes.

A second coating solution is prepared as follows:

1.5 g phthalic acid (toner), 1.5 g AO-80 as developer, 0.2 g TCPAN, 0.15 g cadmium bromide solution (0.5 molar in methanol) 2 drops of 48 percent hydrobromic acid, 0.9 g of a 55 0 , 25 molar mercury (II) acetate solution in methanol and 5 ml of a solution of 0.8 g of a sensitizing dye (Lith 454 of the formula given below) in 100 ml of N-methyl-pyrrolidone are added to 5 g of a mixture of equal parts by weight of acetone and methanol . The mixture is stirred until nothing dissolves. The mixture is then diluted to a total of 25.0 g with a 15% by weight solution of cellulose acetate propionate (CAP) with 10% methanol, 38% acetone and 37% methyl ethyl ketone. Everything goes into solution. The solution is then applied to the coated film in a thickness b5 of 0.08 mm and dried at 82 ° C. for 5 minutes

The film obtained is with 10,000 meter candle seconds (light temperature 6000 ° K) by a continuous

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Gray wedge of optical density 0 to 4 exposed and then 60th becomes a Dmax value of 1.36 and a Dmin value of 0.95

Developed for seconds at 127 ° C in a fluorocarbon bath. receive. Compared to a blue filter, a Dmax value of

A Dmax value of 1.80 and a Dmin value of 0.09 3.30 and a Dmin value of 1.35 are obtained.

receive. The film has a sensitivity of 3.2 x 10 ~ 2 ASA

at 0.10 density units above the base density. s Example 12

When exposing the same film and 300 seconds Ent- A solution of 0.5 g of 1-methylimidazole and 0.5 g of silver

wrap at the same temperature will have a Dmax value entered in 25 g of an aqueous solution of polyvinyl alcohol

2.5 and a Dmin value of 0.10 and a sensitivity of 0.1 mm in thickness on a 0.1 mm thick polyester film

4.5 x 10 "2 ASA at 0.10 density units applied over the underlay and dried for 15 minutes at 77 ° C.

get density. This shows that the film has a wide development. A second coating solution with a solid content width with excellent suppression of the Dmin of 20% (5% cellulose butyrate and 15% cellulose propionate) in

Owns value. Methanol and 0.2 g TCPAN, 3.0 g phthalic acid, 3.0 g de-ent

The silver image obtained with this recording material winder AO-80.0.8 g ammonium bromide is in a 4 weight percent

rial surprisingly in the top layer and not in the cent solutions methanol and 5 ml of that in Example 8

Layer that originally contained the silver salt complex. 's described solution of the sensitizing dye

This recording material is also exposed to electrons until all solids are dissolved. Then radiation becomes sensitive. apply the solution in a thickness of 0.04 mm over the first coating and dry for 6 minutes at 77 ° C. The film

Example 9 is 5 seconds over a Leitz projector with a Wol-

5 g of a mixture of equal parts by weight of acetone and 20 framfadenlämpe exposed and 60 seconds at 127 ° C in one

Methanol is developed with 1.2 g of ethyl imidazole, 0.75 g of silver nitrate, fluorocarbon bath. It becomes a Dmax value of 1.4

0.17 g of zinc nitrate, 0.17 g of mercury (II) nitrate, 0.6 g of TCPAN, 0.2 and a Dmin value of 1.12 were obtained. When washing off the g of phthalic acid, 1.0 g of A0-80 developer, 0.10 g of a 0.5 molar top layer with methyl ethyl ketone, the water-soluble aqueous mercury (II> bromide solution and 5 ml of the in-layer shows a direct positive with a Dmax -Value of 0.99 and game 8 solution of sensitizing dye 25 with a Dmin value of 0.55 The alcohol-soluble top layer is mixed in. The mixture is diluted according to Example 8 until shows a negative image which shows a Dmax value by subtraction The solution is then 0.90 and Dmjn 0.13.

Thickness of 0.09 mm on a 0.1 mm thick polyester film. From this example it can be seen that by suitable wear and exposure in the manner described in Example 8. A negative-positive strip system

Development takes 45 seconds at 138 ° C in a 30th.

Fluorocarbon bath. There will be a Dmax of 1.90 and one

Dmin value of 0.14 obtained. Example 13

* 6 g of a mixture of equal parts by weight of acetone and

Example 10 Methanol are mixed with 1.2 g of 2-ethylimidazole and 1.0 g of silver

This example explains the suitability of a silver salt step. Then 3 drops of a 0.5 molar complex-containing emulsion in direct positive systems. Solution of mercury (II> bromide in methanol added.

5.0 g of a mixture of equal parts by weight of acetone and simple paper is impregnated with this solution. To

Methanol are mixed with 1.2 g of ethyl imidazole, 0.75 g of silver nitrate, the paper is dried by a negative

0.15 g zinc nitrate, 0.15 g mercury (II) nitrate, 0.60 g TCPAN, ~ documents exposed and brought into contact with a sheet,

a drop of 48 weight percent hydrogen bromide 10 impregnated with hydroquinone. The two leaves are

acid, 0.2 g phthalic acid and the sensitizing dye Lith heated in contact on a roller for 5 minutes at 127 ° C.

454 offset. The solution is diluted to that described in Example 8.

Diluted in a manner, then a sheet soaked in a salt complex soaked in a polyester film, obtained an easily readable image, and exposed. The film is 100 seconds at 138 ° C in a This example shows that the binder for the activity

Fluorocarbon bath developed. A sepia-colored 45 of the silver salt complex is formed in thermographic or photot

Direct positive with a Dmax value of 0.88 and a hermographic film is not responsible for the activity

Dmin value of 0.45. Compared to a blue filter, the is.

Dmax value 1.72 and the Dmin value 0.56.

The EASP used in the previous examples

Example 11 50 resin is an alcohol-soluble cellulose propionate that still

According to Example 10, a film is produced, exposed and contains hydroxyl groups in sufficient quantity so that it develops in. Instead of the mercury (II) nitrate, however, alcohol is soluble. EASB is an alcohol-soluble cellulose

0.2 g cadmium nitrate used. Compared to a neutral filutyrate. The Lith 454 sensitizing dye has the formula

CH2 - N - CH2C00H «(C2H5) 3N

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Example 14

0.15 g of silver sulfate and 0.4 g of 2-ethylimidazole are dissolved in an 8% by weight solution of the copolymer Gantrez 235 in a mixture of methanol and isopropanol in a weight ratio of 75:25. The solution is applied to a polyester film in a thickness of 0.127 mm and dried at 75 ° C. for 6 minutes.

A second solution of 1.5 g of phthalic acid, 0.2 g of TCPAN and 2.0 g of the developer AO-80 in 10 ml of a 16% by weight solution of the copolymer Gantrez 235 in a mixture of equal parts by weight of methanol and isopropanol is mixed with 1 ml of a 0.25 molar mercury (II) acetate solution and 6 drops of a 4.8 weight percent solution of hydrobromic acid in methanol are added. The solution is applied to the first layer in a thickness of 0.1 mm and dried at 75 ° C for 5 minutes.

The film obtained is exposed to a photographic negative using a mercury lamp for 1 minute (about 105 lumens) and then developed at 52 ° C. for 30 seconds. An image with a Dm; n value of 0.23 and a Dmax value of 0.78 is obtained.

Example 15

Example 14 is repeated with 0.3 g of silver nitrite and 0.6 g of 2-ethylimidazole for the first coating solution. A good image is obtained after the same exposure, but through a microfilm negative, and the same heat development.

Example 16

0.13 g of silver cyanide and 0.3 g of 2-ethylimidazole are dissolved in a mixture of 10 ml of methanol and 10 ml of a 12% by weight solution of a polyvinyl butyral in a mixture of methanol and butanol in a weight ratio of 68:20 and in a thickness of 0.13 mm applied on a polyester film and dried at 75 ° C for 5 minutes.

Then a solution of 0.6 g of hydroquinone and 0.08 g of mercury (II) bromide in 10 ml of methanol and 10 ml of a 16% by weight solution of the copolymer Gantrez 235 in a mixture of equal parts by weight of methanol and butanol in a thickness over the first coating of 0.1 mm and dried at room temperature. Exposure is then carried out according to Example 14 and heat is developed. An image with a Dmin value of 0.3 and a Dmax value of 0.9 is obtained.

Example 17

Example 16 is repeated with 0.13 g of silver cyanate instead of the silver cyanide. Virtually the same results are obtained.

Example 18

0.12 g of silver phosphate and 0.6 g of N-methylimidazole are dissolved in a mixture of 15 g of distilled water, 5 g of methanol and 1 g of polyvinylpyrrolidone and then applied in a thickness of 0.13 mm to a polyester film and 5 minutes at 75 ° C dried. A second coating solution with developer of the same composition as that in Example 1 is then applied to a thickness of 0.13 mm and dried. After exposure and development according to Example 15, a clearly visible image is obtained.

Example 19

A 1 molar solution of a complex of silver carbonate and 1-methylimidazole in water is mixed with 5 ml of a 5% by weight aqueous solution of polyvinyl alcohol and applied in a thickness of 0.1 mm to a polyester film and dried at 60 ° C. for 5 minutes.

Then a second solution of 5 ml of methyl ethyl ketone, 5 ml of methanol, 0.1 g of AO-80 developer and 0.02 g of phthalazanone and 1 ml of a 1% mercury (II) bromide solution in methanol is applied over the first coating and Dried for 10 minutes at room temperature. After 15 seconds exposure through a microfilm negative with a mercury lamp and 30 seconds development at 125 ° C, a good quality image is obtained.

Example 20

0.75 g of silver nitrate and 0.06 g of 2-ethylimidazole in 11.25 g of methanol are mixed with 12 g of a 25% by weight solution of the copolymer Gantrez ES-335-1 in isopropanol and applied to a polyester film in a thickness of 0.05 mm and dried at 70 ° C for 6 minutes.

A solution of 12.8 g of methanol, 0.285 g of triphenylmethyl bromide, 1 ml of a 3.19% mercury (II) acetate solution in methanol, 4.5 g of A0-80 developer is developed on this coating in a thickness of 0.56 mm ] er, 6.0 g of phthalic acid, 0.5 g of TCPAN and 72 g of a binder solution composed of 80 percent by weight of methanol, 10 percent by weight of butanol, 10 percent by weight of EASB and 5 percent by weight of EASP. This second coating is dried for 5 minutes at 80 ° C.

The film is exposed to a carbon arc lamp through a photographic negative for 25 seconds and developed at 125 ° C for 30 seconds. An image with a Dmin value of 0.05, a Dmax value of 1.4 and a gamma value of 1.49 is obtained.

Example 21

Example 20 is repeated with 0.83 g of the silver salt of pyruvic acid instead of silver nitrate. With identical exposure and development, an image with a Dmjn value of 0.05 and a Dmax value of 1.53 is obtained.

Example 22

Example 20 is repeated with 1.00 g of the silver salt of trifluoroacetic acid instead of silver nitrate. After identical exposure and development, an image with a Dmin value of 0.07, a Dmax value of 1.48 and a gamma value of 1.49 received.

Example 23

Example 20 is repeated with 0.74 g of silver acetate instead of silver nitrate and with 12.0 g of a 12% by weight solution of polyvinyl butyral in a mixture of methanol and butanol in a weight ratio of 68:20. After identical exposure and development, an image with a Dmin value of 0.05, a Dmax of 1.53 and a gamma of 1.35.

Example 24

Example 23 is repeated, but 1.11 g of silver 2-ethylhexanoate are used instead of silver acetate. After identical exposure and development, an image with a Dmin value of 0.06, a Dmax value of 1.53 and a gamma value of 1.46 is obtained.

Example 25

Example 23 is repeated with 0.755 g of silver citrate instead of silver acetate. After identical exposure and development, an image with a Dmjn value of 0.14, a Dmax value of 1.42 and a gamma value of 0.84 is obtained.

Example 26

Example 23 is repeated with 1.725 g of silver stearate instead of silver acetate after identical exposure and development5

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the image has a Dmjn value of 0.63, a Dmax value of 1.41 and a gamma value of 0.38.

The recording material of the invention may also contain other conventional additives, for example toners and reducing agents, such as those described in US Pat. Nos. 3,392,020.3 446,648, 3,667,958.3 667,959.3 672 904.3 679 426.3 751249 , 3 751 252, 3 751255.3 801 321.3 782 941 and 3 794 488 and British Pat. No. 1 163187, sensitizers and sensitizing dyes as described in US Pat. No. 3,679,422.3 666 477, 3 761279 and 3,719,495 are: image intensifiers of the type described in U.S. Patent 3,708,304, color couplers of the type described in U.S. Patent 3,531,286, development inhibitor-releasing compounds of the type described in U.S. Patent 3,700,457, decolourable light absorption dyes of the type described in US Pat. No. 3,745,009, mercury compounds 15 of the type described in US Pat. No. 3,589,903. Processes and structures of those described in US Pat 764 329.3 769 019.3 589 901.3152 904 (Reissue Patent 26 719), 3 607 282.3 685 993.3 679 414.3 21816 6 and 3,756,829 may also be used for the recording material of the invention.

The use of the silver salt complexes for the construction of thermographic or dry-silver-process recording material offers various advantages over the known recording material. An improvement is indeed 25

thing to see that these silver salt complexes can be used in the form of a solution for coating, in contrast to the silver salts used in the known photothermographic recording materials, which have to be ground into the support.

This is also a simple test for complex formation because the addition of a complexing agent such as N-methylimidazole generally causes the silver salts to dissolve in most solvents. This simplifies the production of thermographic recording material in film form.

The thermographic films can be constructed so that they can be used with known developers. The greater the stability of the silver salt complex, the greater the reducing power of the developer that is used to reduce the silver ions to metallic silver. For a given reducing power of the developer, the silver salt complex can be constructed in such a way that it has the appropriate stability for this developer, so that a constant development time can be used for different combinations of silver salt complexes and developers.

Some insoluble silver salts can also be used for the purposes of the invention if the ligand is soluble.

Claims (11)

625064 PATENT CLAIMS 1. Process for the production of thermographic or photothermographic recording material using silver salt complexes with a total stability constant of the complexing agent from 4.50 to 10.00. 2. Thermographic drawing material based on silver, produced by the process according to claim 1, consisting of a support and at least one layer of a binder, a reducing agent and a silver compound, characterized in that the silver compound is at least one silver salt which is formed by at least one complexing agent an overall stability constant of 4.50 to 10.00 is complexed, at least 90% of the total silver salt being present in the layer in the form of a silver salt complex with the complexing agent. v i_. 3. Thermographic recording material according to claim 2, characterized in that at least 95% of the total silver salt in the layer is in the form of a complex with the complexing agent. 4. Thermographic recording material according to claim 2, characterized in that the silver salt is an organic silver salt. 5. Thermographic recording material according to claim 2, characterized in that the silver salt is an inorganic silver salt. 6. Thermographic recording material according to claim 2, characterized in that the complexing agent contains an imidazole group which can complex silver ions. 7. Photothermographic recording material based on silver produced by the process according to claim 1, consisting of a support and at least one layer of a binder, a reducing agent and a silver compound, characterized in that the silver compound is at least one silver salt which is formed by at least one complexing agent with a Total stability constant of 4.50 to 10.00 is complexed, with at least 50% of the total silver in the layer being in the form of a silver salt complex and with at least 90% of the total silver salts, not including photographic silver halide, being in the form of a silver salt complex with the complexing agent and wherein 0.25 to 50.0 mole percent silver halide, based on the total silver, is in catalytic proximity to the silver salt complex 8. Photothermographic recording material according to claim 7, characterized in that the silver salt complex is in physical contact with the silver halide 9. Photothermographic recording material according to claim 7, characterized in that at least 95% of the total silver salt is present in the layer in the form of a complex with the complexing agent. 10. The photothermographic recording material as claimed in claim 7, characterized in that at least one of the complexing agents is a compound having an imidazole group which can form a silver ion complex. 11. Photothermographic on drawing material according to claim 7, characterized in that 1 to 15 mole percent silver halide, based on the total silver, is in catalytic proximity to the silver salt complex. Photothermographic recording material is exposed to light in an imagewise manner and then developed by heating. In the case of thermographic recording materials, the image is generated and developed by heat. In the Exposure creates silver atoms within the photothermographic recording material, which catalytically accelerate the reduction of organic silver salts. In the subsequent heat treatment, silver is deposited from the organic silver salt in the vicinity of the silver atoms. The most successful photothermographic process to date, the “dry silver process”, is described in US Pat. No. 3,457,075 (DT-OS 1572 203). This patent describes recording material which contains a light-stable organic silver salt, a reducing agent and a light-sensitive silver halide. The silver halide is formed by converting a smaller proportion of the organic silver salt into the corresponding halide. The exposure creates a latent image of silver nuclei, which accelerate the further deposition of silver from the organic silver salt. Subsequent heating in the presence of a reducing agent in the image layer produces a negative. The invention of photothermographic recording material described in this patent represents a significant advance because the sensitivity of this recording material is significantly increased and the sensitivity of previous silver halide photographic recording materials is almost achieved .