DE3820592A1 - METHOD FOR REDUCING SENSITIVATION OF SILVER HALOGENIDE PHOTOGRAPHIC EMULSIONS - Google Patents

Abstract

Silver halide photographic emulsions made by precipitating silver halide crystals in a protective colloid solution, growing them up to the size required and optionally removing the excess ions are reductively sensitized introducing into the emulsion in an amount 100-500 mu mol/mol of silver halide by an inclusion complex consisting of a cyclodextrin of the general formula (I> CD-(O-R)K (I> or a cyclodextrin polymer of the general formula (II> <IMAGE> containing 30 to 70% of cyclodextrin and having an average molecular weight of 2000 to 15000 as well as a hydrazine derivative of the general formula (III> R<1>-NH-NH-R<2> (III> the molecular ratio of the cyclodextrin monomer in the inclusion complex to the sensitizing agent, being between 4:1 and 80:1.

Description

The invention relates to a method for Reduction sensitization of a silver halide photo graphic emulsion using the inclusion complexes of Hydrazine derivatives with substituted cyclodextrins or with water-soluble cyclodextrin polymers.

The goal of chemical sensitization the silver halide crystals is that their given portion under a milder exposure ent becomes windable. One method of raising awareness is the reductive process, resulting in several hundreds Centers of sensitivity consisting of very  designed small size on the crystal surface will.

Tin (II) verbin is used as the reducing agent dung, ascorbic acid, formamidine sulfinic acid and silanes used (H. Frieser, E. Klein; basics of photo graphic processes with silver halides; Academic Publishing company, Frankfurt, volume II, p. 677, 1968). Aminoborane (US-PS 37 61 276) or gaseous water fabric (US-PS 38 91 446 and 39 84 249) are also on reversible.

Reductive sensitization by hydrazine has been known for a long time (it was founded in 1943 described in US-PS 24 10 690), their industrial Application was not widespread, however, as the emulsion is veiled by a low amount of hydrazine (see e.g. S. S. Collier: Internationaler photographischer Congress, ICPS, p. 130, Rochester 1978).

That is why hydrazine and its derivatives (e.g. hydrazine dihydrochloride, phenylhydrazine hydrochloride, p-methylsulfonamidoethyl-phenylhydrazine etc.) for Schleierbil used in direct positive emulsions as in the US-PS 37 61 276 is described.

The fog-forming property is with the ver relatively strong reducing effect of hydrazine and linked some of its derivatives; this is precisely what makes it so possible these substances such. B. phenylhydrazine, naphthyl hydrazine, hydrazobenzene, aliphatic hydrazine derivatives, Carboxyphenylhydrazine, diphenylhydrazine etc. as photogra phical developers in addition to suitable components (T. J. James; The Theory of the Photographic Process, p. 310, New York 1977).

The aim of the invention is the hydrazine derivatives for reductive sensitization of photographic emulsions usable. The application of these connections can be interesting because their oxidation in the photoemulsion  is irreversible, which makes its effect different from that of others wise cheap, but in industrial realization problematic sensitization by gaseous agents material is comparable.

According to Hungarian patent application no. 2455/84 are those with labile, sulfur, selenium or tellurium atoms containing thiazolidine, oxazolidine, imidazolidine and Inclusion complexes of selenazolidine derivatives water-soluble containing various substituents Monomers and polymers advantageous for chemical sensitivity lization of silver halides can be used.

The invention is based on the knowledge that also an aromatic or aliphatic, ring-shaped Hydrazine derivatives containing substituents are capable of water soluble inclusion complexes with cyclodextrin derivatives form.

The invention is further based on the recognizes nis that the hydrazine introduced into inclusion complexes derivatives are capable of reducing sensitization without the Considerably increase the fog value.

The cyclodextrins are cyclic, non-reducing oligo saccharides formed from α - glucopyranose units, which properties are known primarily for their inclusion complexing properties (J. Szejtli: Cyclodextrins and their Inclusion Complexes, Akad´miai Kiadó, Budapest, 1982). The use of the group consisting of 6, 7, or 8 glucopyranose units α -, β - or γ - cyclodextrin was usually spread. These can be produced by enzymatically breaking down the starch.

The α - cyclodextrins contain 18, the b - and γ - derivatives 21, or 24 free alcoholic hydroxyl groups to produce enables various substituted derivatives of the monomer or water-soluble polymers and wasserunlös Liche their reactivity.

The sulfo, or carboxyl derivatives, by Substitution of the monomer (e.g. by reaction with  Chloroacetic acid or butane sultone) are obtained, stand out due to their good solubility in water.

The water soluble cyclodextrin polymers with an average molecular weight can by means of various methods. According to a procedure if cyclodextrin is first obtained an unsaturated polyme derivative that can be risked, which you can then take in yourself or with polymerized a monomer containing no cyclodextrin (J. Polym. Sci. Letters 13, 357 [1975]). After another Method the cyclodextrin molecules with a bifunction nalen connection, e.g. B. with diepoxides or with epichlorohyd rin too linear (straight) or branched chains the non-crosslinked, water-soluble polymers (HU-PS 1 80 597) or substituted by ionic groups, remodeled water-soluble polymers (HU-PS 1 91 101). Used to introduce the ionizing functional groups one reagents used in that used in polymer manufacture React medium with the alcoholic hydroxyl groups (e.g. haloalkylamines or haloalkane carbon acids for the introduction of the amino or carboxyl group) or such reagents that are associated with the epoxy group of the Coupling agent or during the polymer production with the can react on the chain end designed epoxy groups.

In accordance with the invention, the procedure is as follows the precipitation of the silver halide crystals in a protection colloid solution, after its growth to the required size and ge if necessary after removing the excess of ions, for the purpose of reducing awareness, an inclusion complex of a cyclodextrin of the general formula (I),

CD - (O - R) _k (I)

wherein

CD represents a cyclodextrin molecule; R is hydrogen or an R ² CO ₂ H, R ² NH ₂ , (R ² ) ₂ NH, R ² SO ₃ H group, in which R ^{2 is} a C _1-5 linear (straight) or branched alkylene group ; and k represents an integer from 1 to 5,

or from a 30 to 70% cyclodextrin containing Cyclodextrin polymer of the general formula (II),

whose average molecular weight is 2,000 to 15,000 is what

C means a group derivable from the β - cyclodextrin molecule by removing p + s hydroxyl groups; R and R'independently of one another
-CH ₂ -, -CHOH-CH ₂ -, -CH ₂ CHOH-CH ₂ -, -CH ₂ -O- (CH ₂ ) ₂ -O-CH ₂ -CHOH-CH ₂ -,
-CH ₂ -O-CH ₂ -CHOH-CH ₂ - or -CH ₂ -O- (CH ₂ ) ₄ O-CH ₂ - CHOH-CH ₂ group
mean; X represents -OR ¹ -, -OR ² - or -NR ⁴ R ⁵ group; R ^{1 represents} hydrogen or, if the value of r deviates from zero, represents a group which can be derived from the β - cyclodextrin molecule by removing a hydroxyl group; R ² for hydrogen, or -PO (OH) ₂ -, -SO₃H-, R'-NH- (CH ₂ ) _m CO ₂ H-, -R ³ - (CO ₂ H) _u -, -R ³ -SO ₃ H or R ³ -NR ⁴ R ⁵ group, or a group which can be derived from the β - cyclodextrin molecule by removing a hydroxyl group; R ^{2 'is the} same as R ² , except for the group derived from the cyclodextrin molecule; R ³ denotes a C _1-10 group which can be derived from an alkane, the terminal carbon atom of which may be substituted by an oxo group and which is closer to the polymer chain; R ⁴ and R ^{5 are} independently hydrogen or C _1-4 alkyl group; m and n independently represent an integer from 0 to 25; r represents an integer from 1 to 17; p represents an integer from 1 to 18; s and t independently represent an integer from 0 to 7; and u is an integer from 0 to 5,

with the restriction that m, n, r, t and u can also change within a unit and
p + s is 18, and from a hydrazine derivative of the general formula (III),

R ¹ - NH - NH - R ² (III)

wherein

R ^{1 represents} a quinolyl, pyridyl or cyclohexyl group, or a group of the general formula (a), (b), (c), (d), (e), (f), (g) or (h);

R ^{2 represents} hydrogen or a phenyl group; R ^{3 represents} hydrogen, halogen, a C _1-4 alkyl or alkoxy group or a sulfonamido group; R ⁴ and R ^{5 represent} hydrogen or halogen; and R ^{6 is} a C _1-4 alkyl or alkoxy group

exists - in an amount of 10 to 500 µmol / mol, preferably 25 to 100 µmol / mol silver halide, calculated for the reducing agent, in the photographic emulsion, the molar ratio of the cyclodextrin monomer in the inclusion calculated for the sensitizer complex, ie Q = [CD] / [S] 4: 1 to 80: 1, preferably 10: 1 to 50: 1.

To calculate the value of Q:

wherein

c is the amount in g of the cyclodextrin derivative in 1 liter of solution; m denotes the cyclodextrin monomer content in% of the cyclodextrin derivative; and 1135 the molecular weight of the cyclodextrin monomer

is.

In the method according to the invention, the Reduction sensitization with gold sensitization and sulfur can be combined. In this case you can the inclusion complex containing the reducing agent is the same wise before the sulfur and gold connection, or between admit to them or after their introduction.

According to the invention, one can also proceed in such a way that reduction sensitization with sensitize Sulfur and an element of column VIII. Of the periodic Systems (preferably by Ir, Pt, Pd or Ru) combined, the inclusion complex likewise precedes the sulfur bond and which is the element of pillar VIII. of the periodic Systems containing connection, or between those, or can be added after their introduction.

Furthermore, according to the invention, one can also do so go that reduction sensitization after growing the silver halide crystals up to a given size is used, and then the crystals down to a definier th size continue to grow, whereby a core / shell Structure is designed. Raising awareness through Sulfur and gold may be on the top of the bowl area realized.

According to the invention can also be pre-selected hen that the inclusion containing the reducing agent complex after the growth of the crystals to a certain one Size entered in the emulsion, and then the crystal surface recrystallized by the addition of the halide that is needed to design the silver salt, which is less soluble than that formed during the precipitation  Is silver halide.

According to the reducing agent containing inclusion complex before the precipitation of the silver insert halide crystals in the protective colloid solution, which causes the reduction to continue throughout the period of time Crystal formation and growth can play.

In the method according to the invention, the Emulsion after the maturation with the ordinary Additives (with sensitizer dyes, stabilizers, Hardening agents, wetting agents, etc.).

As sensitizer dyes such. B. 1-ethyl 3'-phenyl-2-quino-5'-rhodanine (dye I), 3,3'-diethyl-1'- phenylbenzoxazolidin-ethylidene-2'-thiocarbocyanine (color substance II), 3,3'-diethyl-6,6'-dinaphthyl-9-phenyl-thiocarbocyanine (Dye III) or benzothiazole-phenyl-2-thiohydanotin tetra methine-merocyanine (dye IV) can be used (P. Glafkides: Photographic Chemistry, Volume II. Pages 832-856, Fountain Press, London 1960).

As stabilizers z. B. 4-hydroxy-6-methyl 1,3,3a, 7-tetraazaindole (TAI), 1-phenyl-5-mercaptotetrazole (FMT), mercaptobenzthiazole (MBT), mercaptobenzoxazole (MBO) etc. can be used (G.F. Duffin: Photographic Emulsion Chemistry, pages 138-141, Focal Press, London 1966).

As a hardening agent, for. B. Formalin, Glutar aldehyde, glyoxal, 2,4-dichloro-6-hydroxy-s-triazine, etc. put (T. H. James; The Theory of the Photographic Process, Ed. IV., Page 82, McMillan, New York, 1977).

As a wetting agent z. B. Alkenyl succinic acid Polyglycerides, dodecylphenol polyglycol ethers, saponin, etc. applied (B. M. Derjagin and S. M. Levi: Film Coating Theory, page 162, Focal Press, London, 1966).

The inclusion complex is made in such a way that you have the necessary amount of reductive sensitization by means of an aqueous solution of the cyclodextrin derivative dissolves.  

To form the complex, a 1 to 10% solution of the substituted monomer and a 2 to 20% solution of the water-soluble polymer are made. The sensitizing agent is dissolved in an amount of 10 ^-4 to 10 ^-2 mol / liter in the cyclodextrin solution.

In the process according to the invention, ge if necessary, the verbin listed in Tables 1 to 3 deploying solutions.

Table 1

The compounds derived from the substances of the general formula (I)

Table 3

The compounds derived from the substances of the general formula (III)

The advantages of the method according to the invention can be summarized as follows:

• 1) The hydrazine derivatives according to the invention, with the exception of phenylhydrazine, do not dissolve in water or only very poorly; their hydrochlorides dissolve moderately in water; some of these derivatives dissolve in hot ethanol, but separate from the solution at room temperature.
  In contrast, the same compounds dissolve well even in a concentration of 10 ^-2 mol / liter in the aqueous solutions of the cyclodextrin derivatives, which means that they can be conveniently incorporated into the photoemulsion.
• 2) The hydrazine derivatives decompose in aqueous solutions, but their stability increases in the form of an inclusion complex. For example, the reduction potential of an aqueous solution of phenyl hydrazine, the concentration of which is 10 ^-3 mol / liter, is reduced by 30% during an 8-day storage at 6 ° C .; however, it remains unchanged in a 10% P 1 solution under the same circumstances.
• 3) That in the form of an inclusion complex too given reducing agent exerts a significantly higher sensi bilizing effect than that in an aqueous or al alcoholic solution substance entered in the emulsion; nevertheless, it causes a lower fog value.

The invention is illustrated by the following examples explained in more detail, but is not limited to these examples.

Example 1

One swells and dissolves 10 g of inert gelatin in 100 ml of water, then adds 0.035 mol of potassium bromide, 0.01 mol of cadmium chloride and 0.06 μmol of rhodium complex and the silver halide precipitates at 60 ° C. using 60 ml of 1.4 molar silver nitrate solution. After a heat treatment of 20 minutes, 40 g of inert gelatin are added and the heat treatment is continued for 80 minutes. The emulsion obtained in this way is cooled to 40 ° C. and the pouring additives are added (50 ml of 0.05% dye II solution, 80 ml of 50% glycerol solution, 40 ml of 4% saponin solution, 20 ml of 5% formalin solution and 35 ml of 1% FMT solution based on 1 mol of silver halide). Then the emulsion with a silver content of 1.05 ± 0.05 g / m ^{2 is} applied to a paper support. The photographic characteristics of the control material thus obtained are determined in accordance with standard recommendation No. ISO 6846/1934. The development is carried out for 2 minutes at 18 ° C in a solution having the following composition; 1 g of N-methyl-p-aminophenol sulfate, 20 g of anhydrous sodium sulfite, 4 g of hydroquinone, 10 g of anhydrous sodium carbonate and 1 g of potassium bromide in 1 liter of water, calculated for 1 mol of silver halide.

The solution of the inclusion complexes is avoided 15 minutes after the second addition of gelatin in a thin layer Flow the jet into the emulsion. At the same time, the aqueous or alcoholic solution of the hydrazine derivative, or the chemical sensitization if necessary medium added according to the specific order.

The substances examined are the inclusions complexes of the cyclodextrin monomers that follow here and in the which are drawn with the symbols of the components. The he Results are summarized in Table 4.  

Table 4

The results prove that the Cyclo dextrin derivatives transformed into inclusion complexes Phenylhydrazine increased sensitivity by 40 to 80% results without increasing the haze value. Without Complex formation results in a sensitizer lower gradation and sensitivity, and causes one increased fogging.

Example 2

The procedure is as in Example 1, with the exception that that one formed with different hydrazine derivatives Inclusion complexes of the polymer P 1 in various amounts and mole ratios of the emulsion. The results are summarized in Table 5.  

Table 5

The results show that those added in the form of an inclusion complex Hydrazine derivatives regularly have a higher sensitivity result as their aqueous or alcoholic solutions gene.

Example 3

The procedure is as in Example 1, with the Exception that different inclusion complexes of phenyl hydrazine and 2-quinolyl hydrazine are added to the emulsion. The he Results are illustrated in Table 6.  

Table 6

The results show that the Inclusion complexes, from the structure of cyclodextrin poly mer and the hydrazine derivative, a different Have an effect on sensitivity; in the optimal Complex compositions are both reducing agents more effective than in aqueous solutions.

Example 4

The procedure is as in Example 1, with the exception that that only 0.01 mole of cadmium chloride to the inert gelatin solution there and the silver halide with 60 ml of 1.4 molar silver nitrate or potassium bromide solution fails; one uses those formed with various hydrazine derivatives Complexes of the polymer P 4 as a sensitizer and Dye IV as a sensitizer dye. The results are summarized in Table 7.  

Table 7

From the information it can be stated that all inclusion complexes a significant sensitizing Have effect.

Example 5

The procedure is as in Example 1, except that the inclusion complex P 1 / S 1 is combined with sensitization by sulfur and gold, or by sulfur and palladium. The components are added in the following proportions: P 1 / S 1 = 48 μmol / mol (R); Na ₂ S ₂ O ₃ = 48 µmol / mol (S); NH ₄ Au (SCN) ₂ = 55 µmol / mol (AU); K ₂ PdCl ₆ = 60 µmol / mol (PD). The molar ratio in the inclusion complex is [CD] / [S] = 50. The results are summarized in Table 8.

Table 8

The results prove that the inclusion complex of the reductive sensitizer, especially with others sensitizing substances can be combined, which a higher gradation and sensitivity, respectively a lower fog value compared to that in aqueous Solution used reducing agent can be achieved. Further it can be seen that this is in the inclusion complex Worn phenylhydrazine with the sulfur and gold sensi Sierungsmittel acts synergistically, while that in aqueous Solution reducing agents applied do not have such an effect points (as it compares the sensitivity information in lines 4 and 5 of table 8 with the sum of the sensitivity lightness information of Examples 2 and 3 can be seen).

Claims (4)

1. A process for the reduction sensitization of photographic silver halide emulsions with the precipitation of the silver halide crystals in a protective colloid solution, with their growth to the required size and, if appropriate, with the removal of the excess of ions, characterized in that, for the purpose of reduction sensitization , an inclusion complex - that from a Cyclodextrin of the general formula (I) CD - (O - R) _k (I) wherein CD represents a cyclodextrin molecule; R is hydrogen or an R ² CO ₂ H, R ² NH ₂ , (R ² ) ₂ NH, R ² SO ₃ H group, wherein R ^{2 is} a C _1-5 linear (straight) or branched alkylene group stands; and k is an integer from 1 to 5, or from a cyclodextrin polymer containing 30 to 70% of cyclodextrin of the general formula (II), whose average molecular weight is 2,000 to 15,000, where CD is a group derivable from the β - cyclodextrin molecule by removing p + s hydroxyl groups; R and R'independently of one another
-CH ₂ -, -CHOH-CH ₂ -, -CH ₂ CHOH-CH ₂ -, -CH ₂ -O- (CH ₂ ) ₂ -O-CH ₂ -CHOH-CH ₂ -,
-CH ₂ -O- CH ₂ -CHOH-CH ₂ - or -CH ₂ -O- (CH ₂ ) ₄ O-CH ₂ -CHOH-CH ₂ group
mean; X represents -OR ¹ -, -OR ² - or -NR ⁴ R ⁵ group; R ^{1 represents} hydrogen or, if the value of r deviates from zero, represents a group which can be derived from the β - cyclodextrin molecule by removing a hydroxyl group; R ² for hydrogen, a -PO (OH) ₂ -, -SO ₃ H-, R'-NH- (CH ₂ ) _m CO ₂ H-, -R ³ - (CO ₂ H) _u -, -R ³ -SO ₃ H- or -R ³ -NR ⁴ R ⁵ group, or a group which can be derived from the β - cyclodextrin molecule by removing a hydroxyl group; R ^{2 'is the} same as R ² , except for the group derived from the cyclodextrin molecule; R ³ denotes a C _1-10 group which can be derived from an alkane, the end carbon atom of which is closer to the polymer chain and can optionally be substituted by an oxo group; R ⁴ and R ⁵ independently represent hydrogen or C _1-4 alkyl group; m and n independently represent an integer from 0 to 25; r represents an integer from 1 to 17; p represents an integer from 1 to 18; s and t independently represent an integer from 0 to 7; and u is an integer from 0 to 5, with the restriction that m, n, r, t and u can also change within one unit and
p + s is 18, and from a hydrazine derivative of the general formula (III) R ¹ - NH - NH - R ² (III) in which R ^{4 is} a quinolyl, pyridyl or cyclohexyl group, or a group of the general formula (a), (b), (c), (d), (e), (f), (g) or (h); R ^{2 represents} hydrogen or a phenyl group; R ^{3 represents} hydrogen, halogen, a C _1-4 alkyl or alkoxy group or a sulfonamido group; R ⁴ and R ^{5 represent} hydrogen or halogen; and R ^{6 is} a C _1-4 alkyl or alkoxy group - in an amount of 10 to 500 µmol / mole, preferably 25 to 100 µmol / mole silver halide calculated for the reducing agent, into the photographic emulsion, which is for the Sensitizer calculated molar ratio of the cyclodextrin monomer in the inclusion complex, ie Q = [CD] / [S] 4: 1 to 80: 1, preferably 10: 1 to 50: 1. 2. The method according to claim 1, characterized in that that reductive sensitization with a sensiti combined by sulfur and gold, the inclusion complex likewise before the sulfur and gold compound, or between them, or added after their introduction can be. 3. The method according to claim 1, characterized in that one can sensitize the reductive sensitization with by sulfur and an element of column VIII of the periodic Systems, preferably by Ir, Pt, Pd or Ru combi niert, the inclusion complex likewise before the Sulfur compound and the element of column VIII of the periodic system containing connection, or between which, or after their introduction can be added. 4. The method according to any one of claims 1 to 3, characterized characterized in that the inclusion complex of the reductive Sensitizer before silver halo precipitation genid crystals, or during the period of the crystal enlargement or afterwards admits.