DE935706C - Method of hardening gelatin - Google Patents

Description

The invention relates to a process for hardening gelatin, in particular for the production of photographic ones Materials in which an aqueous gelatin solution is mixed with a hardening agent.

In the manufacture of photographic material, in general, the particularly strong one is used in processing the tendency of the gelatine used to appear at higher temperatures swell or melt by adding hardening agents such as chrome alum, formaldehyde, acrolein, Glyoxal, saturated diketones or the like suppressed.

It has now been found that the diester of methanesulfonic acid according to the general formula

X = (CH ₂ -SO ₃ CH ₃ ) ₂

in which X is either a simple link, a —C ₂ H ₄ —O — C ₂ H ₄ - or one, two, three or four CH ₂ groups, are significantly more effective for hardening gelatin than the usual hardening agents, however without adversely affecting the photographic properties of the layers produced therewith. So z. B. Gelatin emulsions and gelatin layers can be made resistant to swelling or melting through the storage of proportions of the hardening agent, even if they are exposed to elevated temperatures. For the production of photographic material the diester of methanesulfonic acid is introduced into an aqueous gelatin solution or into the ready-to-cast emulsion and the mixture is poured onto the appropriate support. The material is then either exposed to an elevated temperature or deposited for a longer period of time, with so-called hardening occurring. The hardening agent can be added in and of itself in any amount, even though

very small amounts are sufficient to bring about a noticeable increase in the melting point of the gelatin.

In general, however, at least 0.025 part of the curing agent should be used for practically effective curing to 15.5 parts of gelatin can be used.

The ratio of about 0.25 parts hardener to 15.5 parts gelatin was found to be most favorable.

The hardening agent can be used in an amount of up to ^χ / _10th of the weight of the gelatin, although in general an increase in the amount above the stated most favorable amounts merely entails unnecessary expense.

The following examples are provided for in-depth

Explanation of the manufacture and use of hardeners.

Example 1 i, 2-di (methanesulfonoxy) ethane

310 parts of anhydrous ethylene glycol were dissolved in 1500 parts of anhydrous pyridine and 1150 parts of methanesulfonyl chloride were slowly added to the solution with vigorous stirring. The temperature was kept between 5 to 15 ^0. After the reaction had ended, the mass was stirred into three times its volume of finely crushed ice. Washing the crystalline product with ice water and subsequent drying afforded in 77 ° / _o yield the curing agent in the form of white crystals having a melting point at 45 to 47 °.

Example 2 i, 3-Di (methanesulfonoxy) propane

152 parts of trimethylene glycol were dissolved in 600 parts of anhydrous pyridine and 460 parts of methanesulfonyl chloride were slowly added to the solution, which had been kept ^{at 5 to 150, with vigorous stirring.} After the reaction had ended, the resulting mass was stirred into three times its volume of finely crushed ice. The resulting crystals were washed with ice water, dried and recrystallized from ethyl alcohol. The resulting crystalline hardener had a melting point of 41 to 42 ^° .
⁴ S example 3

i, 5-di (methanesulfonoxy) pentane

312 parts of 1.5 pentanediol were dissolved in 2000 parts of anhydrous pyridine and 684 parts of methanesulfonyl were added to the solution, which had been kept ^{at 5 to 150, with vigorous stirring.} After the reaction had ended, the mass was stirred into three times its volume of finely crushed ice. Washing with ice water and subsequent drying of the crystalline product which precipitated out gave white crystals with a melting point of 35 to 36 ^° .

Example 4

g ß, /? '- Di- (methanesulfonoxy) -diethyl ether

There were 212 parts of anhydrous diethylene glycol dissolved in 1200 parts of anhydrous pyridine and 460 parts of methanesulfonyl chloride kept at 5 to 15 ° Solution slowly added with vigorous stirring of the same. After completion of the reaction, the The resulting mass is stirred into three times its volume finely crushed ice and the resulting crystalline product purified as in the previous examples. The resulting white crystals had a melting point of 57 to 58 °.

^The: compounds thus prepared were subjected to about 15.5 g gelatin-containing photographic emulsion, once in an amount of 0.025 S ^(un i in the other in an amount of 0.25 g, is added dissolved in methanol The emulsion was after casting. Cured on a support for one day at 38 ° and 50% relative humidity The degree of hardening was determined by immersing the samples in water at 21 °, which was slowly heated to the temperature at which the emulsion layer separates from the The heating rate was the same in all experiments, the water was stirred during the experiment.

In any case in which the comparison layers, no curing agent is contained, (fused) from the carrier in the range from 43.5 to 50 ⁰ dissolved, it was found that the same but using 0.25 g of a curing agent according to the invention The layers produced remained on the carrier even after the water bath had already reached the boiling point. When using 0.025 S hardening agent, the layers peeled off from the substrate at the following temperatures:

i, 2-Di (methanesulfonoxy) ethane 55 °

i, 3-Di (methanesulfonoxy) propane 99.5 °

i, 5-di (methanesulfonoxy) pentane 63 ⁰

ß, / 9'-Di (methanesulfonoxy) diethyl ether 82 °.

Example 5

ι, 6-di (methanesulfonoxy) hexane

50 parts of hexamethylene glycol were dissolved in 180 parts of anhydrous pyridine and 98 parts of methanesulfonyl chloride were added to the solution, which had been kept at 5 to 15 °, with vigorous stirring. After the reaction had ended, the reaction mixture was stirred into three times its volume of crushed ice. The resulting crystalline product was washed with ice water, dried and purified by recrystallization from ethyl alcohol. The product had a melting point of 57 to 58 ⁰ .

The 1,6-di- (methanesulfonoxy) -hexane produced in this way was used to harden photographic emulsions as follows:

From a photographic silver halide gelatin emulsion containing 8 contained approximately ° / ₀ gelatin, more parts were removed ECM in an amount of 200 and a methyl alcohol solution of 1, 6-di (methanesulfonoxy) hexane, once 0.1, in the other Containing 0.2 and 0.4 g of the hardener was added. The emulsions thus prepared were poured on glass plates, dried at 22 ⁰ and allowed to stand 5o ° / ₀ relative humidity. They were then sealed in foil bags and kept at a temperature of 38 ^{0 for 24 hours.}

keep. The melting points of such emulsion layers were determined by the fact that they were in a Water bath, which was brought to 100 °, were kept. They stayed in the boiling water a maximum of 20 minutes if they have not melted earlier. The melting points of the layers are summarized in the following table, with a layer which contained no hardener as a comparative layer ran along in the experiment:

i, 6-di- (methanesulfone-
oxy) -hexane each 200 ecm
emulsion Enamel
Point Minutes
to ioo ° O
0.1g
0.2 g
0.4 g 43 °
100 °
100 °
100 ° 14th
18th
16

The test results of the layers, the 1, 6-Di- (methanesulfonoxy) -hexane clearly show the difference to the usual layers. As a result, the hardener was not found to be any unfavorable Affects the properties of the emulsions.

It was also found that the layer was left for some time in place of the aging treatment of the gelatin Can be left at normal temperature, after which they are also resistant to boiling water will. So were z. B. 0.05 g of 1,5-di- (methanesulfonoxy) pentane 200 ecm as described above added emulsion produced and poured onto a support. The temperature of the emulsion layer was held at 21 ° for at least 14 days. It was found that the layer in boiling water then no longer melted.

The degree of hardening effect is influenced by the temperature and the relative humidity during the ripening process. If z. For example, if the layers are turned off under normal conditions, more time will be required for ripening than if elevated temperatures are used, and if the ripening process is at an elevated temperature, a decrease in relative humidity will require either an elevated temperature or a longer ripening time in order to achieve the same degree of hardening as compared to a ripening process taking place at a given relative humidity value. So z. B. that a maximum degree of hardening is reached at 38 ⁰ and 50% relative humidity and a day of maturation. If the relative humidity is lower in these optimums, a higher temperature will be required to achieve the same curing effect for a given ripening time. The use of the appropriate values of temperature, relative humidity and ripening time results in a favorable degree of hardening in each case for a given admixture ratio of hardening agents.

As indicated, the invention is not only for making photographic emulsions with sufficient hardness properties, but also applicable to the production of gelatin solutions, which are used for the production of layers on paper, cloth, film or other surfaces be turned. The hardening agents according to the invention can also be used together with others Hardeners, e.g. B. aldehydes or alum can be used.

Claims (3)

PATENT CLAIMS: Means —C ₂ H ₄ —O — C ₂ H ₄ group. i. Process for hardening gelatin, in particular for the production of photographic materials, in which an aqueous gelatin solution is mixed with a hardening agent, characterized in that a compound of the formula X = (CH ₂ —SO ₃ CHg) _{2 is} used as hardening agent, in which X a (CH ₂ ) ₀ _ ₄ - or a 2. The method according to claim 1, characterized in that that the hardener is used in an amount of about 0.25 parts per 15.5 parts of gelatin will. 3. Process according to Claims 1 and 2, characterized in that the hardening agent is 1,2-di- (methanesulfonoxy) ethane and / or 1,3-di (methanesulfonoxy) propane and / or 1, 5-di (methanesulfonoxy) pentane and / or / ?, / 3'-Di (methanesulfonoxy) diethyl ether is used. © 509 575 11.55