DE4231278A1 - Chemical modification of gelatin for silver halide colour emulsion - with 1,1-di:methyl- 3-allyl-sulphonyl- methyl-4-sulpho- methyl- pyrrolidinium betaine, limiting viscosity increase on adding colour coupler - Google Patents

Abstract

Prodn. of chemically modified gelatin (I) for gelatino-Ag halide colour emulsions involves alkaline decomposition of defatted and macerated crushed bone or split cowhide with lime in the usual way, deliming, extn. with hot water, filtration and concn.. The novel features are that, after filtration and before or during concn., the aq. gelatin soln. is adjusted to pH 9.5-10.5; 1,1- dimethyl- 3-allyl-sulphonyl-methyl- 4-sulpho-methyl pyrrolidinium betaine (II) is stirred into this and dissolved at 60-80 deg. C; the pH is re-adjusted after 30-60 min reaction; and the (I) soln. is worked up in the usual way, i.e. conc., set, crumbled and dried. ADVANTAGE - In emulsions contg. (I), the increase in viscosity on adding the colour coupler is very limited, whilst the sensitometric properties of the emulsion and physico-mechanical properties of the film are retained and the brittleness is reduced.

Description

Field of application of the invention

The invention relates to a method for producing che mixed modified gelatin used for photographic purposes suitable is.

Characteristic of the known prior art

Gelatin is used to make photographic emulsions and films applied. Depending on the emul sion type and the film material to be produced demands on the properties of the gelatin, e.g. B. regarding the viscosity of the emulsion, the change effect with the ingredients of the emulsion and the physico mechanical properties of the film.

It is known that with the addition of hydrophilic residual fat color coupling or similar substances to AgHal gelatin emul an increase in viscosity occurs when the gelatin, as is usual in color emulsion practice, with alkali collagen digestion (cremation) was produced. This Viscosity increase is based on the interaction between Gelatin and the hydrophilic residual fat color couplers, such as the z. B. in the work of F. EVVA and I. BERTY, Kolloid-Z. 149, 10 (1956) and H. HERMEL et. al., J. Inf. Rec. Mater. 13, 283 (1985). The increase in viscosity in the Coloremulsion can have a viscosity that is predetermined by casting technology considerably exceed tolerance limits. The then necessary Viscosity is reduced by adding water to the Coloremul sion for drying technology reasons and because of the Redu The solids content is not applicable.

A high viscosity of the hydrophilic residual fat coupler ent holding color emulsion can be avoided according to DD 2 19 306 by using a photo gelatin with less than 14 g together Glutamic acid and aspartic acid building blocks in 100 g gelatin protein and / or 40% to 60% gelatin protein with a Molar mass between 95,000 and 700,000. The from the usual Raw material for the liming process, bovine bones and skins, Photo gelatin produced usually contain more than together 14 g of glutamic acid and aspartic acid building blocks in 100 g gelatin protein.  

The molar mass range of the gelatin between 95,000 and 700,000 regarding, this is according to EP-27 533 co-determining for Solidification speed of the color emulsion: the greater the The content of this molar mass range in the photo gelatin is the more the emulsion solidifies faster.

For this reason, a high percentage is used for the film sprinkling Share of this molar mass range sought, in general over 60%, which adversely affects the viscosity of the hydro phile emulsion containing residual fat color coupler.

One of the physicomechanical properties that the quality determine the film's elasticity or fragility. If it is insufficient, the film elasticity can be added be improved by plasticizers. Common for this are z. B. in Research Disclosure, Dec. 1978, p 27. Other additions to the complicated system that is a color Emulsion and a color film usually increase also its susceptibility to failure. Therefore z. B. the setting of the fragility of the film by the applied Gelatin is preferred.

The chemical modification of the gelatin and is also known their use for photographic purposes. As examples called: With anhydrides of phthalic, maleic and amber acid right (U.S. 2,525,753) or with vinyl sulfone (U.S. 3,132,945) Gelatins are used for the flock technique in the manufacture of AgHal emulsions.

By the reaction of the gelatin with monofunctional alkyl the photographic film for the Schnellver work at high temperature and high pH (JP 51-73433).

Gelatin in which about 50% of their primary amino groups are in Acetoacetamido groups were quickly solidified and is therefore suitable for the quick brewing of more layered materials (U.S. Def. Pub. 886 014).

Gelatin reacted with alkyl sulfone increases sensitivity and gradation, but also the veil of an AgHal emul sion, at least when fresh (GB-1 033 189) and does that Film suitable for physical development (DE 12 24 573).

Aim of the invention

The aim of the invention is to develop a new, chemically modified Photo gelatine for the production of silver halide color To provide emulsions whose emulsion viscosity at Addition of these components increases less than usual is certainly the case.  

The color emulsion made with the new gelatin is said to compared to the gelatins customary for these emulsions have comparable sensitometric values.

State the nature of the invention

The invention has for its object a method for Development of a new photo gelatin with which to develop the viscosity in the production of AgHal color emulsions increase significantly when adding the color couplers to the emulsion can be limited while maintaining the sensitometric values of the emulsion and physico-mechanical Properties of the film. In particular, one should Reduction in fragility can be achieved.

It has been found that the problem is solved when using gelatin
1,1-dimethyl-3-allylsulfonylmethyl-4-sulfomethyl-pyrroli dinium-betaine (allylsulfobetaine, molecular weight 311.4), (formula I)

is reacted.

The alkyl sulfone sulfobetaine is obtained by allylation of natri um-1,1-dimethyl-3-sulfinatomethyl-4-sulfomethyl-pyrrolidinium betaine obtained with allyl chloride and by recrystallization of the crude product additionally purified from water (F. from 307 ° C with decomposition).

The starting product required for the allylation, sodium 1,1-dimethyl-3-sulfinatomethyl-4-sulfomethyl-pyrrolidinium betaine, in turn, is obtained by sulfocyclosulfination of Dimethyldiallylammonium chloride with sodium bisulfite after DD-2 25 128, Example 2.

The gelatin is produced in the usual way. To the Example is of degreased and macerated bone meal or beef slit, this opened lime-calcium decalcify the digested material with hot water ex trapped, filtered and concentrated.  

After filtration before or during concentration pH in the warm gelatin solution is from 9.5 to 10.5, preferably set from 10 and then the allylsul fobetain stirred in. It gradually dissolves when stirred in and immediately reacts with the gelatin. Then the pH value reset to the initial value and the gelatin solution processed in the usual way, d. H. to end on concentrated, chilled, crumbled and dried.

Since the reaction time (30 to 60 minutes) and thus the tempe raturation and alkali exposure of the gelatin solution during the um can be kept short with allylsulfobetaine the degradation of higher molecular weight gelatin to peptides does not serious.

The amount of allylsul required to convert the gelatin fobetain is made on a sample of the gelatin solution to be reacted determined as follows:

In 100 g of the gelatin solution (corresponding to 10 g of gelatin dry substance) is adjusted exactly to pH = 7.0. Then 0.1 N NaOH is added dropwise until pH = 10. The consumption of 0.1 N NaOH is measured. The order calculation factor is:

Number of ml 0.1 N NaOH per 1 g gelatin × 311/1000
= Number of kg of allyl sulfobetaine per 10 kg of gelatin.

This figure gives a 100% conversion of the gelatin. Gün Properties as photo gelatine for color emulsions hydrophilic residual fat color couplers are already included to achieve sales of 50% and below.

The chemically modified gelatin produced according to the invention has a reduced viscosity compared to the unmodified one in aqueous solution and a significantly reduced viscosity when hydrophilic residual fat color couplers are added ( FIG. 1).

If he uses gelatin according to the invention with a degree of chemical conversion of up to 35% for the production of layers and films, the layers and films also have a reduced brittleness ( FIG. 2).

The photographic properties of the AgHal color emulsion are compared when using the gelatin according to the invention the chemically unmodified not adversely changed, esp not when this is mixed with unmodified is used.

Embodiments example 1

10 kg hot water degreased and macerated bone meal open to the limestone in the 50 days (liming), at pH = 4-5 decalcified, at pH = 5.8 to 6.2 and a temperature from 50 to 70 ° C, filtered through cotton linters and concentrated up to 13.3% in a vacuum evaporator. This gelati The solution is separated into two equal parts.

Part 1 is solidified, crumbled and dried in the usual way net (unmodified gelatin; gelatin A).

Part 2:
7.5 ml of the gelatin solution (corresponds to 1 g gelatin) are removed. By adding 0.1N NaOH dropwise, pH = 7 is set, then pH = 10. The consumption of 0.1N NaOH from pH = 7 to pH = 10 is 2.55 ml for 1 g of gelatin Gelatin solution is adjusted to 50 ° C. by adding 33% NaOH pH = 10 and 0.3965 kg allylsulfobetaine per 10 kg gelatin is stirred in with constant stirring and heating to 80 ° C. That corresponds to 50% sales. After a reaction time of 30 minutes at 80 ° C., the pH is brought back to 6.2 and the gelatin is further concentrated, solidified, crumbled and dried in the usual way (chemically modified gelatin; gelatin B).

The gelatins have the following viscosities:
native viscosity, 10% gelatin solution, pH = 8, T = 40 ° C

A 19.0 mPas

B 13.3 mPas.

Coupler viscosity with hydrophilic yellow coupler, 5% gelatin solution, pH = 8, T - 40 ° C, coupler / gelatin ratio = 0.3 native with yellow coupler

Coupler viscosity with hydrophilic yellow coupler with different coupler / gelatin ratio
Fig. 1.

Example 2

As stated in Example 1, it becomes unmodified and chemical modified gelatin produced, with the difference that the chemical modification of the gelatin between 10% and 50% is made.

With these, chemically modified to varying degrees Gelatins are poured layers in the following way:

20 g of gelatin are distilled in 180 g. Water swelled at room temperature for 1 hour and then melted at 60 ° C. 60 ml of this gelatin solution are poured onto a silanized, precisely horizontal glass plate measuring 23.8 × 17.8 cm ² , distributed evenly and with bubbles using a curved glass rod and then left to solidify. The solidified layer is dried in a stream of air at 20 ° C. and 50% rh for 48 hours. The dry gelatin layers are approx. 90 µm thick. They are pulled off the glass plate and cut into 2.5 cm strips. The gelatin strips are conditioned for a further 48 hours at 25 ° C / 50% rh. The brittleness is then measured using the drop hammer method. The drop hammer value (FH / cm) is a measure of the brittleness of the gelatin layer. The larger it is, the lower the brittleness of the layer, ie the more elastic it is.

Fig. 2 shows that the brittleness of the layer is reduced up to a degree of modification of 35%.

Example 3

As stated in Example 1, it becomes unmodified and chemical modified gelatin.

They are called chemical post-ripening gelatin in a negative recipe used, per kg of emulsion a 40 g of silver equivalent amount of AgHal and 85 g of photo gelatin. In the Photographic examination carried out in the usual way results in ge compared to a type gelatin:

Claims (1)

Process for the preparation of chemically modified gelatin for gelatin-containing silver halide color emulsions by de-degreased and macerated bone meal or beef cleavage in the usual way, calcified, the decalcified product is decalcified, extracted with hot water, filtered and concentrated, characterized in that after filtering before or during the concentration in the aqueous gelatin solution, a pH of 9.5 to 10.5 was set, and 1.1Dimethyl-3-allylsulfonylmethyl-4-sulfomethylpyrrolidiniumbetaine was stirred in and dissolved at 60 to 80 ° C., after a reaction time from 30 to 60 minutes the pH value is reset and the gelatin solution is further processed as usual, ie concentrated, solidified, crumbled and dried.