DE1020864B - Process for the preparation of light-sensitive photographic emulsions - Google Patents

Description

GERMAN

It is known that the general sensitivity of photographic, optionally optically sensitized Silver halide emulsions can be increased by the use of various means.

This increase in the sensitivity of photographic emulsions can e.g. B. by adding small amounts of certain sulfur-containing compounds or reducing agents such as stannous chloride, hydrazine and water-soluble ones Formaldehyde sulfoxylate salts. Depending on the substances and methods used It is generally believed that chemical sensitization is due to either the formation of silver sulfide on the surface of the silver halide crystal or on the small amount resulting from the reduction of the silver halide Amounts of silver is due.

After another sensitization process, small amounts of metal compounds, such as gold, platinum, etc., added. However, the views go beyond the theoretical explanation of the sensitizing Properties of such compounds are completely different.

It has now been found that the general sensitivity of photographic, optionally optically sensitized Silver halide emulsions can be increased if, under suitable conditions, so-called Imino-aminomethanesulfinic acid compounds are added.

The new method is particularly valuable because the usual one with sulfur or natural gelatin sensitizers or with metal compounds such as gold, platinum and palladium, sensitization achieved by addition can be increased by sensitizers according to the invention.

The iminoaminomethanesulfinic acid compounds are known to be distinguished by their reducing properties and have found application in various areas of the chemical industry; in the U.S. Patent 2,339,309 is e.g. B. the use of such compounds in photographic processing baths for the reduction of silver salts in photographic Layers described. One can therefore, without in any way restricting the scope of the invention, for several reasons assume that the sensitization method according to the invention is based on the effect of the minor amounts of silver produced during the reduction of the silver halide are based. The oxidized thiourea derivatives have significant advantages over the reducing agents previously known as sensitizers, since surprisingly, they result in an excellent higher increase in sensitivity.

The term "iminoaminomethanesulfinic acid compounds" used in the present invention indicates compounds of one of the following tautomeric structures:

procedure

for the production of light-sensitive photographic emulsions

Applicant:

Gevaert Photo-Products NV,
Mortsel, Antwerp (Belgium)

Representative: Dr. W. Müller-Bore, patent attorney,
Braunschweig, Am Bürgerpark 8

Claimed priority:
Great Britain 29 April 1955

Laurent Pierre Roosens, Antwerp,

and Paul August Faelens, Schoten (Belgium),

have been named as inventors

HO,

o ^r

N.

—C;

(A)

and

IS =

(B)

NH-

Dielminoaminomethanesulfinic acid compounds can be readily substituted on thiourea or its N-substituted Derivatives and hydrogen peroxide or sodium permanganate are represented.

Some researchers refer to the oxidized reaction product of thiourea and hydrogen peroxide "Thiourea dioxide"; they relate to the structure of formula (B). Others choose the term "formamidinesulfinic acid" or »Iminoaminomethanesulfinsäuretf corresponding to the structure of formula (A).

The presence of an imino and an amino group on the carbon atom reduces the effects of the reaction products of thiourea or thiourea derivatives substantially different from the simpler Sulfinic acids, such as. B. methanesulfinic acid

HO

CH,

their addition to silver halide emulsions to remove chemical haze from U.S. Patent 2 057 764 is known.

709 809/302

In a similar way, oxidized reaction products, which are prepared from hydrogen peroxide and N-substituted thiourea derivatives, as thiourea dioxide derivatives (some researchers choose the term »Formamidinsulfonff) according to formula (B) or as Formamidinesulfinic acid or iminoaminomethanesulfinic acid derivatives according to formula (A) are considered.

Probably there is a balance between the two desmotropischen forms in such a way that the compounds according to the formulas (A) or (B) a change of physical factors such as temperature and pressure, or chemical effects (e.g., p _H value) of the one can pass into the other form. In an alkaline medium there is also the possibility that salts, such as sulfinates, are formed in accordance with the desmotropic form according to formula (A). With regard to the equilibrium between the two desmotropic forms (A) and (B), the oxidized thiourea derivatives can also be regarded as formamidinesulfinic acid betaines and can be illustrated by the following intramolecular ionoid structures:

is to be made dependent. Therefore, in the present invention, the term 'iminoaminomethanesulfinic acid compounds' is always used. used.

In the preferred embodiment of the invention, the new sensitizers correspond to one of the following tautomeric formulas:

^ 2

—-NH

, 0 O

° ^he

© .
NH

It should be noted, however, that the invention does not take away from the largely theoretical discussions Structure of the oxidized compounds derived from substituted or unsubstituted thiourea,

N O

he P a

SC K ₃ and

ON - R ₁ O

NH-R ₁

-M ¹ DD

HO ₂ S

Here, R _{1 is} an alkyl or alkenyl group, a hydrogen atom or a divalent _{radical connected to R 3} for closing a heterocyclic ring, R _{2 is} a hydrogen atom or a divalent _{radical connected to R 3} for closing a heterocyclic ring, R _{3 is} an alkyl (including substituted alkyl), alkenyl, aryl or heterocyclic radical, a hydrogen atom or a single bond _{linked to one of the divalent radicals R 1} or R _2.
- When R _{3 is} a substituted alkyl group, the can

^a 5 substituent can also be an iminoaminomethanesulfinic acid radical; such compounds can be referred to as di- (formamidinesulfinic acid).

As sensitizers are e.g. B. the following Iminoaminornethansulfinsäureverbindungen particularly suitable (the compounds are illustrated according to the above-mentioned tautomeric structure (A)):

made after that of Barnett E. de Barry,
J. Chem. Soc. (London), 97 [1910], p. 63,
described method;

HO ₂ SC :::

NH-CH ₂ -CH = CH ₂

Cl

HO ₂ SC

NH

NH

the same

the same

GH2 '

4. HO ₂ SC CH ₂ -CH ₂

NH

H (J ₂ S - L

6. HO ₂ SC

7. HO ₂ SC

'NH

, NH - CH ₂ - CH ₂ - CH ₃

NH

NH-CH ₂ -CH = CH ₂

N-CH ₂ -CH = CH ₂

the same

made after that of R. Kitamura,

J. Pharm. Soc. Japan, 57 (1937), p. 818 (ref. Chem.

Abstracts 33 1939], p. 1726)

method

the same

desg].

, NH - CH ₂ - CH, - CH, - CH,

HO ₉ S

N-CH ₂ -CH ₂ -

■ CHo - CHo manufactured according to that of R. Kitamura,

J. Pharm. Soc. Japan, 57 (1937), p. 818 (ref. Chem.

Abstracts 33 [1939], p. 1726)

method

NH

HO ₉ SC

"N

the same

N-CH,

HOoS-C

HOoS-C

NH

N-CH ₂ -CH = CH ₂

. NH-CH ₂ -CH ₂ -CH ₂ -CH ₂ -CH ₂ -Nh desgl.

"C-SO ₂ H desgl.

HO ₂ SC

NH
NH-C = O

N -NC ₆ H ₆

These compounds become either the raw materials for emulsion preparation or the emulsion even added at any point in time of their production, either alone or together with other agents influencing the emulsion in any desired sense, e.g. B. together with stabilizers, Additives to shift the hue or increase sensitivity, optical sensitizers, Dye formers, hardeners and wetting agents, etc. Those used to sensitize the individual emulsions The most suitable substances and the quantities to be used vary from emulsion to emulsion can be different and are most easily clarified by means of preliminary tests. In general, however, the iminoaminomethanesulfinic acid compound is used added in an amount of 0.05 to +5 1% silver parts by weight.

The new sensitizers can be used alone or with other chemical sensitizers, such as those known for them Sulfur compounds (e.g. allyl isothiocyanate, allyl thiourea, sodium thiosulfate, potassium selenocyanide), and use the natural gelatin sensitizers. The iminoaminomethanesulfinic acid compounds can be added to the emulsion before, after or simultaneously with the sulfur sensitizers, e.g. B. during ripening.

Together with both, the sulfur and reduction sensitizers, or with the reduction sensitizer alone, metal compounds, ζ. B. those of gold, platinum and palladium are added, which increases the sensitivity enables. The iminoaminomethanesulfinic acid compounds are particularly effective for increasing the general Photosensitivity of orthochromatic, panchromatic, x-ray and all special Emulsions as well as optically non-sensitized emulsions.

An advantage of this invention is that the iminoaminomethanesulfinic acid compounds can be used together with dye formers and optical sensitizers without adversely affecting one another

manufactured according to that of EW Esslinger,
J. Amer. Chem. Soc, 37 (1915), p. 183,
described method.

can. This fact is significant when one considers general sensitivity by adding one of the new sensitizers of a single or multi-layer color photographic material is intended to increase.

Another advantage is that the method is generally applicable because of its simplicity, for example for Production of photosensitive material for amateur and professional photography and for cinematography, for 35mm photography, for repro material and for scientific and industrial applications.

The invention is illustrated by the following examples, without being restricted in any way:

example 1

A washed, coarse-grained gelatin-iodobromide silver negative emulsion (Average size of the grain 0.8 μ), the silver halide of which consists of 95 mol percent silver bromide and 5 mole percent silver iodide is ripened at 45 ° C. After adding a panchromatic sensitizing Dye and other customary emulsion additives are applied to the emulsion on a suitable film base potted (sample A).

Two further samples are prepared in such a way that the emulsion is either 20 mg Allyl thiourea dioxide (sample B) or 0.6 mg thiourea dioxide (sample C) per 100 g of silver present can be added. The rest of the treatment is the same as for sample A.

Sensitometric results

sample News
Sensitizer Relative
Sensation
opportunity Y veil A.
B.
B. none
20 mg allylthio
urea dioxide
0.6 mg thiourine
substance dioxide .... 100
180
190 0.85
0.90
0.88 0.02
0.02
0.02

Example 2

A washed gelatin / chlorobromide silver emulsion of the type used in reproduction processes (Average size of the grain 0.4 μ) and their silver halide from 36 mol percent silver chloride and 64 mol percent Silver bromide is ripened at 42 ° C. After adding chrome alum, potassium bromide, saponin and other customary emulsion additives, the emulsion is poured onto a suitable film substrate (sample A).

Another sample is prepared in the same way, but with the addition of 200 mg allyl thiourea dioxide per 100 g of silver present for the emulsion at the beginning of ripening (sample B). Further treatment is as in sample A.

Sensitometric results substance dioxide (sample B) or 10 mg thiourea dioxide (sample C) per 100 g of silver present for the emulsion at the beginning of ripening. The rest of the treatment is the same as for sample A.

Sensitometric results

sample News
Sensitizer Relative
Sensation
opportunity Y veil A.
B. none
200mgAUylthio-
urea dioxide 100
190 5.15
5.15 0.01
0.01

Example 3

A washed, fine-grain gelatin-bromide-silver cinema-positive emulsion (Average size of the grain 0.1 μ) is ripened at 54 ° C. After adding the usual emulsion additives, the emulsion is applied to a suitable film substrate potted (sample A).

Two more samples are prepared in the same way, but with the addition of 400 mg allylthiourine

sample News
Sensitizer Relative
Sensation
opportunity Y veil A.
B.
C. none
400mgAUylthio-
urea dioxide
10 mg thiourine
substance dioxide 100
210
200 4th
4.20
4.35 0.01
0.01
0.01

Example 4

A washed, fine-grain iodobromide silver emulsion with an inert gelatin as a binder is made up to Achieving optimal sensitivity in the presence of one of the new sensitizers, if necessary under simultaneous addition of a sulfur sensitizer, heated to 50 ° C and then on a suitable film base shed. There will also be one non-sensitized and one containing only a sulfur sensitizer Comparative emulsion produced. The formulas of the iminoaminomethanesulfinic acid compounds used are given on the second and third pages. Each sample contains an amount of silver bromide that is 100 g Silver equals.

Sensitometric results

sample

Sulfur sensitizer

New sensitizer in l ° / _o by weight solution Relative
sensitivity

veil

1 2 3 4 5 6 7

10 11 12 13 14 15 16 17 18 19 20

none

cm ³ Na ₂ S ₂ O ₃ , 1% ,, like. like. like. like like. none none none none none none none none none none none none none

none none

0.02 cm ³ connection 0.2 cm ³ connection 2 cm ³ connection 6 cm ³ connection 20 cm ³ connection 0.02 cm ³ connection 0.2 cm ³ connection cm ³ connection cm ³ connection

6 20 12 12

1.2 12 12 12 12 12

cm ³ connection cm ³ connection cm ³ connection cm ³ connection cm ³ connection cm ³ connection cm ³ connection cm ³ connection

cm ³ connection

22nd 0.50 100 1.10 160 1.10 240 1.25 200 1.10 250 1.30 250 1.35 30th 0.55 60 1.05 50 1.05 60 1.10 65 1.20 40 0.70 65 1.20 60 1.05 65 1.15 65 1.20 65 1.20 60 1.10 65 1.15

0.1 0.1

0.1 0.1 0.1 0.1 0.1

0.1

0.1 0.1

0.1

0.1 0.1

0.1

0.1

0.1 0.1 0.1 0.1

0.1

From this information it appears that the simultaneous use of one of the new sensitizers is related with a sulfur sensitizer (sample 5) causes a greater increase in sensitivity than the optimal one Effect of the separate application of the individual sensitizers is to be expected (samples 3 and 10).

Although in the above examples only gelatin-halosilver emulsions are described, the invention is not limited to the application of this colloid. Emulsions consisting of other water-permeable colloids can also be used for the purposes of the invention raise awareness. Such layer formers are z. B. agar-agar, zein, collodion, water-soluble cellulose derivatives, such as hydrolyzed cellulose acetate, cellulose esters of oxycarboxylic acids, e.g. B. lactic or glycolic acid, alkali metal salts of dicarboxylic acid cellulose esters, such as pthal

acids, polyvinyl alcohol and partially hydrolyzed polyvinyl acetate, and interpolymers of vinyl acetate with unsaturated compounds such as styrene and maleic acids, water-soluble polyvinyl acetals and other hydrophilic ones synthetic and natural resins or polymeric compounds.

The iminoaminomethanesulfinic acid compounds can be used to sensitize known silver chloride, Silver bromide, silver] odide emulsions and emulsions consisting of mixtures of these halides use.

Claims (2)

PATENT REQUIREMENTS: 1. Process for the production of photosensitive, optionally optically sensitized photographic emulsions, characterized in that the An iminoaminomethanesulfinic acid compound added to the emulsion to increase general sensitivity which preferably corresponds to one of the following tautomeric formulas: H (X ^ o * R ₃ and NR ₁ 0 ' ' ^N ^ NH-R ₁ Herein R ₁ is an alkyl or alkenyl group, a hydrogen atom or a divalent, connected to close a heterocyclic ring with R ₃ radical, R ₂ represents a hydrogen atom or a divalent, connected to close a heterocyclic ring with R ₃ radical, R ₃ is an alkyl - (including substituted alkyl), alkenyl, aryl or a heterocyclic radical, a hydrogen atom or a single bond linked to one of the divalent radicals R ₁ and R ₂ . 2. The method according to claim 1, characterized in that the photographic emulsion ir. In the presence of a sulfur or a natural gelatin sensitizer. Considered publications:
U.S. Patent No. 2,057,764. © 709 809/302 12.57