DE1178297B - Process for increasing the general sensitivity of photographic silver halide emulsions and photographic materials for carrying out the process - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

GERMAN

PATENT OFFICE

EDITORIAL

Boarding school Class: G 03 c

Number:
File number:
Registration date:
Display day:

German KL: 57 b -8/02

A 43236IX a / 57 b

May 31, 1963

17th September 1964

The invention relates to a method for increasing the general sensitivity of halogen silver emulsions, especially highly sensitive silver bromide emulsions.

It is known that the general sensitivity of photographic silver halide emulsions can be reduced can be improved by adding polyalkylene oxides to the emulsions (see US Pat. No. 2,423,549), halogenated polyalkylene oxides (see German Auslegeschrift 1 125 765) or condensation products of alkylene oxides with amines, carboxylic acids, alcohols, amides or phenols (cf. USA patents 1 970 578 and 2 213 477) added in low concentrations. To achieve a significant Effect, it is necessary to use polyalkylene oxides whose molecular weight 1500 to 2000 and is more. The lower polyethylene oxides with fewer than 20 ethylene oxide groups are photographic indifferent and are therefore not suitable for chemical sensitization highly sensitive Emulsions. A serious disadvantage associated with the use of long-chain polyalkylene oxides as an emulsion additive is that these compounds are a concealment of the emulsions. This veil, as is often shown in the literature, can be through the common antifoggants such as nitrobenzimidazole, benzotriazole or mercapto-containing compounds, do not eliminate completely.

It has also been proposed that reaction products of spirocyclic pentaerythritol bis (phosphoric acid monohalides) and to use polyethylene glycols to reduce the gradation of photographic chlorosilver emulsion layers coated with a formaldehyde-containing hydroquinone developer will increase.

It has now been found that reaction products of spirocyclic pentaerythritol-bis-phosphoric acid monohalides) with relatively low molecular weight polyethylene glycols containing 3 to 50 ethylene oxide residues as a means to increase the general sensitivity of halogen silver emulsions with at least 50 mole percent silver bromide are suitable when considering the development of these halide silver emulsion layers carries out in the presence of the reaction products mentioned, surprisingly these reaction products have, in contrast to the known, relatively high molecular weight Polyethylene glycols do not have the undesirable property of haze photographic emulsions during storage, especially at higher temperatures and high humidity.

Process for increasing the general sensitivity of photographic silver emulsions and photographic materials
to carry out the procedure

Applicant:

Agfa Aktiengesellschaft,

Leverkusen, Kaiser-Wilhelm-Allee

Named as inventor:

Dr. Herbert Grabhöfer, Cologne-Flittard,

Dr. August Randolph, Leverkusen,

Dr. Wilhelm Saleck, Schildgen via Bergisch

Gladbach

The reaction products mentioned can be obtained by condensation of spirocyclic phosphoric acid esters the general formula

CH ₂ -OO

OO -H ₂ C

II / \ /

x - p c

\ / ^N

O H2C

CH ₂ -O

where X = chlorine or bromine, with a polyethylene glycol of the general formula

HO- (CH ₂ -CH ₂ -O) _n -H II

where η = 3 to 50, are obtained, the glycols mentioned being used preferably in amounts of about 1 to 2 mol per liter of the halides mentioned.

The condensation products from the spirocyclic phosphoric acid esters have proven to be particularly advantageous of the general formula I with the following polyethylene glycols:

Hexaethylene glycol,
Non-ethylene glycol,
Octadecaethylene glycol,

Polyglycol, which contains about 30 to 35 ethylene oxide groups.

The reaction products can also be obtained by heating the components to about 100 to 180 ^° C. in vacuo, the hydrogen chloride released being removed by the gas phase.

409 687/256

The substances obtained from these reactions are generally water-soluble. You are preferred the silver halide photographic emulsion layers added, amounts of about 10 to 200 mg per mole of halosilver being used, but they are also suitable as additives to developer solutions, preferably used in amounts of 30 to 600 mg per liter will.

Particularly suitable photographic silver halide emulsions are bromoiodide silver emulsions, the halogen silver salts of which consist of about 1 to 10 mol percent of iodide silver, are preferably the above reaction products are added to the emulsions after they have reached optimum sensitivity have matured. The emulsions can be sulfur sensitizers in a manner known per se, Gold salts or other agents used to increase sensitivity, as well as stabilizers such as azaindolizine, contain optical sensitizers and hardeners.

example 1

A silver bromide gelatin emulsion containing 0.3 mol of halogen silver per kilogram of casting solution an iodine content of 6 mole percent, based on 1 mole of halosilver, was used with the necessary Additives such as wetting agents, optical sensitizers, stabilizers and hardeners, provided and cast on a suitable film carrier (sample A). In parallel tests, the Emulsion as a pouring additive, the following substances are added per kilogram of emulsion:

Sample B

160 mg nonethylene glycol,
Sample C

160 mg condensation product from 1 mol pentaerythritol bis (phosphoric acid monochloride) and

1 mole of nonethylene glycol.

All samples were exposed in a sensitometer behind a gray scale wedge and 10 minutes in a developer with the following composition at 18 ° C:

Example 2

After adding 160 mg of the condensation product from 1 mol of pentaerythritol bis (phosphoric acid monochloride) and octadecaethylene glycol to the emulsion described in Example 1 and after With the same treatment, the following sensitometric properties were determined:

Test sample B. Sensitive
difference in time
in DIN gradation veil Control sample
without addition .. relation 0.70 0.05 160 mg sample
Condensation
product + 2.5 0.65 0.06 e i s ρ i e 1 3

An emulsion as in Example 1 was used in the developer specified there once without (sample A) and once with 400 mg of the condensation product of 1 mol pentaerythritol bis (phosphoric acid monochloride) and a polyglycol with 30 to 35 ethylene oxide groups per liter of developer solution (sample B) Developed minutes at 18 ^{C C.}

Result

Attempt
sample Sensitivity
difference in 'DIN gradation veil A.
B. relation
+ 2 0.70
0.70 0.06
0.07

Sodium sulfite, sicc 70 g

Borax 7 g

Hydroquinone 3.5 g

Monomethyl-p-aminophenol 3.5 g

Sodium citrate 7 g

Potassium bromide 0.4 g

Make up to 1 liter with water.

Result

Attempt
sample Sensitivity
difference in ° DIN gradation veil A.
B.
C. relation
± 0
+ 2 0.70
0.60
0.65 0.05
0.06
0.07

Claims (3)

Patent claims: 1. Method of increasing common sensitivity of photographic silver halide emulsions containing at least 50 mole percent silver bromide, the emulsions being used in the presence developed by polyglycol derivatives, characterized in that as Polyglycol derivatives condensation products from spirocyclic pentaerythritol bis (phosphoric acid monohalides) and polyethylene glycols with 3 to 50 ethylene oxide residues are used. 2. Photographic light-sensitive material comprising a halide silver emulsion with at least 50 mole percent bromine silver for carrying out the method according to claim 1, characterized by the content of one Condensation product according to claim I. 3. Photographic formaldehyde-free developer mixture for carrying out the process according to claim 1, characterized by the content of a condensation product according to claim 1.