DE1296973B - Use of copolymers as peptizers in the production of photographic silver halide emulsions - Google Patents

Description

1 2

The first step in the preparation of photo- having recurring units of the formula: silver halide emulsions is well known in the peptization of by double environmental - Γ CH ₂ - CH ₂ - CH - CH -1 - setzungvonlöslichenSilbersalzenmitAlkalihalogeniden I sparingly soluble silver halide formed, and 5 [ ABj either in the presence or absence of

Ammonia. The peptization is intended to prevent where A and B are amino or carboxyl groups, that, first, the silver halides interpret in too large a way, with each unit not being more than one Crystals are precipitated and secondly contains an aggre- amino group and the ratio of aminogate ion of the silver halide crystals takes place. An effective to carboxyl group is 1: 1.25 to 1: 5, as peptisame Peptization is said to continue the growth of the sating agent during silver halide formation Silver halide crystals during the preparation of the photographic silver halide dispersion affect as the result of the wax emulsions.

particle size distribution resulting from the size of the crystals The copolymers used according to the invention

According to the USA.-Reissue-Patentmetrische Properties of the photographic emulsification described in US Pat. No. 2,047,398 sion, such as, in particular, sensitivity, contrast, processes can be produced. It is not necessary, Graininess and sharpness. that all anhydride residues of the copolymers

A known and customary peptizer for being converted into amino or carboyxl groups. Silver halides in the production of photographic devices have been found to be particularly advantageous Silver halide emulsions is gelatin. A disadvantage of copolymers has been shown to be the molecular weight The use of gelatin as a peptizer was weighted according to a specific viscosity of however, is that they are quite sensitive to the 0.02 to 1.0 range. Although the copolymers Attack by bacteria is and because they are used from natural in the most varied of concentrations Raw materials cannot always be produced more evenly, since it has proven to be advantageous is available. Furthermore, it is shown in a ratio to the silver halide Compatibility of gelatin with other polymers from 0.07: 1 to 0.35: 1 to use. Binders quite limited. The copolymers used according to the invention

Although other substances are already used as a gelatin substitute, sate are characterized in particular by the fact that they such as, in particular, synthetic polymers, as peptides, influence grain growth in a favorable manner, sation agent in the production of silver halide d. that is, as opposed to using as known emulsions, but it has been shown that these gelatin substitutes known synthetic polymers, Substances either insufficient peptization of such. B. polyvinyl alcohol and polyvinyl pyrrolidone, Cause silver halides or, such as. B. Poly- sufficiently large silver halide grains obtained, vinyl alcohol and polyvinylpyrrolidone, the grain 35 So form, especially in a neutral medium The growth of the silver halides is so greatly impaired. These polymers are used as peptizers that well-formed and sufficiently large ones are relatively large during silver halide formation Crystals with the requisite photographic tabular octahedral grains of an advantageous one Properties cannot be preserved. photographic sensitivity. The when using

From US Pat. No. 2,565,418 and the formulation of the mixed polybritics used in accordance with the invention It is also known from patent specification 648 472 to reduce the available particle size distribution Flocculation of already formed gelatine differs clearly from that which containing silver halide emulsions with polymers when using gelatin as a peptizing agent repeating units of the formulas is obtained. So lead according to the invention

45 applied copolymers, as can be seen from Example 2 below, z. B. to grain size

\ division curves with sigma values that are larger than im

I I case of using gelatin.

Let \ COOH NH _{2 / J3i e} copolymers according to the invention

_{un (} j 50 can also be used as a peptizer during the

Silver halide formation in an ammoniacal medium

Use _ / _ CH CH CH ₂ CH ₂ -X-. The silver halide obtained in this case

Ii; 1 grains have a cubic crystalline structure. in the

\ COOHCOOH / others can use the new peptizers

55 ammoniacal silver halide emulsions of unusually high silver halide concentration and the flocculation can be made by lowering the without deposits or SedipH value bring about on 4 to 5.5. ment formations that occur in the manufacture of the same

The object of the invention is to use a highly concentrated emulsion with gelatin as for the peptization of the peptization agent used in the production of emulsions can often be observed, forming silver halide suitable synthetic occurrence.

Specify polymer, which is based on grain wax It has also been shown that the silver halide

tum and grain size distribution has a beneficial effect. grain size to a certain extent by changing the The invention relates to the use of the ratio of amino to carboxyl groups in the Copolymers obtained by copolymers can be controlled by copolymers according to the invention sation of ethylene and maleic anhydride as well as can.

selective conversion of the anhydride residues obtained.

tten polymers in amino and carboxyl groups, phological changes in the silver halide crystal

3 4

effect stalls. Furthermore, at a constant _ ^ _rT ". _ ,. ",,

Silver ion concentration Changes in the physical ^B ) Production of a neutral silver halide

The speed of development can be determined when emulsion

the ratio of amino to carboxyl groups in the To 30 ml of an aqueous, 3.275 g potassium bromide,

for the peptization of the silver halides which are formed 5 0.1 g of potassium iodide and 1.0 g of the copolymer copolymers used is changed. containing solution was over the course of 30 minutes

Given in the presence of the inventively used a solution of 3.82 g of silver nitrate (20 ml). Copolymers precipitated silver halide grains during the silver nitrate addition, the solution was stirred can be continued after washing with a variety of known and at a temperature of 70 ⁰ C colloidal binders such as gelatin, held io. After all of the silver nitrate had been added to polyvinyl alcohol or a mixture of ethyl acrylate and acrylic acid, 10 more miniature polymers were combined at the same temperature, whereupon the obtained th is further stirred.

Emulsions by known methods to the usual The emulsion obtained contained well dispersed

photographic supports can be applied. tabular octahedral silver halide grains, those The copolymers can produce numerous grains with straight edges and sharp ones Position copying and direct copying silver corners of triangular shape were added. the Both halide emulsions and emul diameters of these grains ranged from 0.33 to 3.26 evolvable-type versions can be used. Micron. The mean grain projected area was Using the copolymers, the 0.996 square microns, the half width of the grains of the most varied of common silver halides peptized size distribution curves, can be evaluated as a "sigma function". The emulsions available can also press, corresponding to a sigma value of 1.634 also for making photographic materials for square microns, and the number of voids per the silver salt diffusion transfer method as well as grain averaged 8.5 as by X-ray color photographic Materials which coupler analysis was found. One for comparison below bindings included. The use of gelatin as a peptizer The silver halide emulsion prepared from the copolymers had an average value Berhalide emulsions can also have a typical grain area of 0.826 square microns, while the Way with known chemical and / or spectral half-width of the grain size distribution curve in Sensitizers, e.g. B. the U.S. patent - in this case a sigma value of 0.807 square microns 3 039 873, columns 10 and 11, corresponded to the described relationships and an average of 9.1 false bonds per grain, be sensitized. len were determined. The "coefficient of variation" The following examples are intended to elaborate on the invention (100 sigma / mean grain projection area) illustrate, for the preparation of the mixed poly 164.1 for the use of (ethylene - /? - aminomerisate however, no protection is sought. acrylic acid-ethylene maleic acid) copolymer made

35 provided emulsion, while for the emulsion produced using gelatin as a peptizing agent

Example 1 sion a value of 99.7 was determined. The under Ver

using the copolymer produced silver

A) Production of an ethylene-ß-aminoacrylic acid halide emulsion had a stability that of one

Ethylene maleic acid copolymer with a 40 using gelatin as a peptizing agent

The ratio of amino groups to carboxyl groups to the silver halide emulsion prepared was superior.

of 1: 3 The use of the (ethylene-ß-aminoacrylic acid

Ethylene maleic acid copolymer does it too

In a 5-1 three-necked flask with a stirrer, possible to add the silver halide grains through an additive Inlet tube for nitrogen, thermometer and 45 acid to coagulate, soluble salts present Drying tube was fitted, a solution was then washed out and the grains in again To disperse 100 g of a low molecular weight ethylene maleic acid a film-forming binder. anhydride copolymer in 800 ml of concentrated

Given sulfuric acid. The solution was a total of Example 2

46.5 g of sodium azide were added and the temperature was ^{kept between 40 and 48 °} C. using that described in Example 1, with the necessary copolymer as peptization agent, if one was cooled from the outside. After all the sodium-ammoniacal silver halide emulsion had been prepared and added aside, the solution was added for 2 hours to 30 ml of a 3.14 g potassium bromide, 0.1 g potassium

95 ° C heated, in order to facilitate stirring iodide and 1.0 g of the copolymer from Example 1 and to suppress the foaming of the solution, a solution containing 55% was added to 20 ml of a solution of ligroin. The solution was then allowed to overflow, the 3.82 g of silver nitrate and then allowed to cool slowly overnight. The ammonia solution contained the initially formed low, the copolymer was then redissolved by pouring it into a blow, whereupon acetone was stirred in a thin stream with vigorous stirring for a further 39 minutes. The temperature during the addition of the finely divided silver precipitated form, whereupon it was with acetone nitrate 60 45 ⁰ C. The dispersion obtained had been washed and dried. a stability similar to that of a corresponding,

The dried copolymer was dissolved in 800 ml using gelatin as a peptizer Dissolved water and diluted the solution to 2 liters. Was superior by prepared silver halide emulsion. Adjusting the pH of the solution to the iso- It mainly contained cube-shaped silver halide electrics Point, d. H. about 2.4, this then became 65 grits with diameters of 0.50 to 1.76 microns. the Copolymer precipitated again, then mean grain projection area in this dispersion with water and acetone and dried again. The dimension was 1.581 square microns, the width at half maximum was the booty amounted to 78 g. Grain size distribution curve corresponded to a sigma

value of 0.61 square microns, and the number of voids per grain averaged 9.4. One in contrast, had an emulsion prepared in the same way, but with gelatin as the peptizing agent a mean grain projection area of 1.048 square microns, while the half width of the grain size distribution curve for this emulsion corresponded to a sigma value of 0.464 square microns and per grain an average of 6.2 voids were present. The »coefficient of variation« as defined in example 1 is ίο contributed 38.7 for those with the (ethylene - ^ - aminoacrylic acid-ethylene maleic acid) copolymer peptized emulsion and 44.2 for the emulsion made using gelatin as a peptizer.

15 Example 3

To 30 ml of a solution which contained 6.98 g of potassium bromide, 0.226 g of potassium iodide and 1.0 g of the copolymer from Example 1, an aqueous, 8.495 g of silver nitrate and enough ammonia were added while stirring The precipitate which formed from the ammonia to the silver nitrate had just redissolved, and the aqueous solution (20 ml) was allowed to flow in over 85 seconds, followed by stirring for a further 39 minutes. The temperature during the addition of silver nitrate was 45 ^° C. The silver halide grains remained completely suspended, while, in contrast, the silver halide grains settled under the same conditions when gelatin was used as a peptizing agent instead of the copolymer.

Example 4

A) Preparation of a (ethylene - ^ - aminoacrylic acid-ethylene maleic acid) copolymer with a ratio of amino groups to carboxyl groups

from 1: 5

This copolymer was prepared in the same way as described in Example 1, but with the difference that this time only 31 g of sodium azide were used. The isoelectric precipitation of the Copolymer takes place at pH 1.9. 49 g of mixed polymer were obtained.

B) As described in Example 1, this copolymer was used to produce a neutral silver halide emulsion produced, but this time stirring was not carried out minutes, but 30 minutes after the silver halide formation was completely terminated. The stability of the obtained silver halide emulsion corresponded to the emulsion described in Example 3. The emulsion contained tabular octahedral ones Silver halide crystals 0.33 to 3.5 microns in diameter.

Example 5

As described in Example 2, using the copolymer from Example 4 as Peptizer prepared an ammoniacal silver halide emulsion. The stability of this emulsion was again better than that of a corresponding manner using gelatin as a peptizer prepared silver halide emulsion. The emulsion contained cubic silver halide grains with diameters from 0.59 to 1.67 microns.

Example 6

A) Preparation of an (ethylene-ß-aminoacrylic acid-ethylene maleic acid) copolymer with a ratio of amino groups to carboxyl groups

from 1: 1.5.

According to the method described in Example 1, a copolymer was prepared by adding 100 g of an ethylene-maleic anhydride copolymer of average molecular weight with 62 g of sodium azide implemented. The yield was 73 g. Isoelectric precipitation in this copolymer occurs at pH 2.1.

B) As described in Example 4, this peptizing agent was used to produce a neutral silver halide emulsion containing tabular octahedral grains 0.5 to 3.3 microns in diameter. the The emulsion obtained was again more stable than one in a corresponding manner using gelatin silver halide emulsion prepared as a peptizer.

Example 7

Using the copolymer according to Example 6, an ammoniacal one was obtained as in Example 2 A silver halide emulsion composed of cubic grains with diameters of 0.4 to 2.8 microns. The stability of the emulsion was again better than that of a corresponding emulsion, made using gelatin as a peptizer.

Example 8

A) Production of a (ethylene - ^ - aminoacrylic acid-ethylene maleic acid) Miscnpolymerisats with a ratio of amino groups to carboxyl groups

from 1: 1.5

As described in Example 1, 126 g of the

low molecular weight ethylene-maleic anhydride copolymer reacted with 78 g of sodium azide, 40 g of copolymer with an isoelectric Point of 3.5 were obtained.

B) As described in Example 4, this peptizing agent was used to produce a neutral silver halide emulsion produced which, like the emulsions of the previous examples, proved to be extremely stable and their tabular octahedral silver halide grains were 0.5 to 4.3 microns in diameter.

Example 9

Using the copolymer from Example 8, as described in Example 2, a ammoniacal silver halide emulsion. This emulsion consisted of cubic silver halide grains with diameters from 0.6 to 1.8 microns.

35

60

Example 10

A) Production of a (ethylene-zS-aminoacrylic acid-

Ethylene maleic acid) copolymer with a ratio of amino groups to carboxyl groups

from 1: 1.25

A solution of 126 g of a low molecular weight ethylene-maleic acid copolymer in 800 ml of concentrated Sulfuric acid was cooled to 8 ° C in a 5-1 three-necked flask. The piston was with one

Equipped with stirrer, thermometer, nitrogen inlet tube and drying tube. While stirring were the Solution a total of 97 g of sodium azide are added in such proportions that the temperature is always between 8 and 12 ° C. The reaction mixture was then stored in a cooling bath at 8 ° C. for a further 16 hours, whereupon the bath was removed. The temperature rose spontaneously to 40 ° C. As soon as this again began to fall, the solution was heated to 95 ° C for 2 hours after which it was cooled and the product was precipitated by pouring into acetone in a fine stream. The copolymer obtained was washed thoroughly with acetone and then dried.

The dried copolymer was then dissolved in 800 ml of water, the solution to a volume of 21 diluted and the pH adjusted to 5.2, wherein the copolymer precipitated again. It was washed with water and then with acetone and finally dried again. The yield was 65 g.

B) With this peptizer, as described in Example 4, a neutral emulsion was prepared, which, like the emulsions of the previous examples, was extremely stable. This emulsion consisted of tabular, octahedral silver halide grains 0.6 to 5.5 microns in diameter.

Example 11

Using the copolymer from Example 10 as a peptizing agent, as in Example 2, an ammoniacal silver halide emulsion was prepared. The emulsion possessed like the emulsions of the previous examples, excellent stability and contained cubic Silver halide grains 0.3 to 2.6 microns in diameter.

Example 12

After that by EI P erry in »Phot. May be. Eng. «, 5, pp. 349 to 354 (1961), was described to the different effects of different ethylene-ß-aminoacrylic acid-ethylene maleic acid) copolymers, ie copolymers with different ratios of amino groups to carboxyl groups, on the surface of the silver halide grains and during development processes such as physical development to show the relative (ie compared to gelatin) dissolution rate of silver halide sol crystals peptized by a particular peptizer in a photographic developer with 0.004033 moles of p-methylaminophenol sulfate, 0.01102 moles of sodium sulfite and 0.04481 moles sodium carbonate in each case per liter of solution (see. the cited reference, p 350) as well as the relative speed at a supplied by a silver ion thiosulfate constant silver ion concentration of 4 x 10- ¹³ moles / liter at 25 ° C (see. the cited literature reference S. 350) in the presence of the peptis in question ation means determined. The test results obtained are summarized in the following table.

relationship
of amino groups
to carboxyl groups
in the copolymer Molecular weight of the for the
Production of the copolymer
used starting ethylene
Maleic anhydride
Mixed polymer
(specific viscosity) * Relative
Release speed
the peptized
Silver halide crystals
(Gelatin = 1) Relative speed
the physical
development
at a constant
Silver ion concentration
(Gelatin = 1) 1: 5
1: 3
1: 1.5
1: 1.5
1: 1.25 low (about 0.1)
low (about 0.1)
medium (about 0.6)
low (about 0.1)
low (about 0.1) 28.9
10.3
7.5
6.4
6.0 18.8
10.1
5.6
5.2
3.5

• Determined using a 10% solution of the polymer in dimethylformamide at 25 ° C according to that of Winding and Hi 11 in "Polymeric Materials", McGraw-Hül Book Co., Inc., USA., 1961, p. 44, described method.

The following two examples show that the copolymers used according to the invention structurally very similar polymers are unable to peptize silver halides.

Example 13
(Comparative example)

A neutral emulsion was prepared as described in Example 1, except that it was used as a peptizer an (ethylene-ammonium maleamate) copolymer was used. The received Emulsion was completely unstable; that is, the silver halide grains were not peptized but coagulated.

Example 14
(Comparative example)

Using the same copolymer from Example 13, an attempt was made to obtain an ammoniacal Emulsion as described in Example 2 to be prepared, but no emulsion even remotely stable could be obtained.

These results show that this is the case when the copolymers according to the invention are used as a peptizer during silver halide formation in the dispersion of silver halides extremely favorable result actually obtained was completely surprising.

Claims (1)

Claim: Use of copolymers obtained by copolymerizing ethylene and Maleic anhydride and selective conversion of the anhydride residues of the resulting polymers into Amino and carboxyl groups, with repeating units of the formula - - CHo - CHo - CH - CH - AWAY wherein A and B are amino or carboxyl groups, each unit not being more than one 909523/391 Contains amino group and the ratio of amino to carboxyl groups is 1: 1.25 to 1: 5 as a peptizer during silver halide formation in the manufacture of photographic silver halide emulsions.