DE91505C - - Google Patents

Description

IMPERIAL 7k

PATE N TA M T

The present invention relates to the production of gelatin plates BEZW. Gelatin foils, in which the gelatin in a hardened state or in one in warm or hot water insoluble form, so that they can no longer or only with difficulty be liquefied can. This fact is of outstanding importance for practical use such gelatin plates respectively. Gelatin foils for a wide variety of technical purposes, see above z. B. also for photographic purposes.

After the work of Dr. Hauser and Dr. Opponent (Münchener medicinische Wochenschrift No. 30 and 32, 1893), nutrient gelatine, which on top of gelatine also contains protein bodies, Contains peptone, alkali carbonate and other nutrient salts if they are the result of bacterial cultures is liquefied, solidified again by the action of formaldehyde vapors in such a way that they no longer liquefy at body heat in dry air.

Further experiments have now shown that not only bacteria are already contaminated by bacteria. liquid or ' peptonized or otherwise modified gelatin by formaldehyde Solidification can be brought about, but also that pure ones melted at body temperature aqueous gelatin solidified by formaldehyde.

It was also found here that this pure gelatin, solidified in this way, even in warm water or insoluble in hot boiling water.

Furthermore, it has also been found that solid, unchanged gelatin, by the action of Formaldehyde also insoluble in warm or hot water respectively. infusible at higher temperatures will.

It was also established that when such solid gelatin is treated with formaldehyde solution this success is fully achieved in the desired measure, if one allowing this formaldehyde solution to dry out after immersing the gelatin.

In these experiments the very important fact was established in practice that the Gelatin obtained after drying on the base does not appear cracked, but coherent, crystal clear, elastic cover.

These experiments and investigations have now led to the one described below Production of insoluble in warm water gelatin plates, gelatin foils bezw. Gelatin dry plates.

It happens this production of those insoluble in warm water BEZW. heavy soluble gelatin plates, gelatin films, gelatin coatings according to the present invention Action of formaldehyde to such an extent that it is difficult to dissolve or insoluble Gelatin is formed. This is now successfully effected by placing them in a solution of formaldehyde immersed and then allowed to dry up. After the formaldehyde has dried out, it has

then the gelatin BEZW the desired nature of the insolubility. Poor solubility in warm water. You can also replace the formaldehyde solution with such substances, formaldehyde is released by their mutual action, as well as by formaldehyde gas, the use of which however generally not recommended for practice as one. certain degree of hardness This way, security is not enough for all cases. ..

The execution may be based on the following examples closer to the invention. Find explanation:

Gelatine plates, gelatine foils or coatings, depending on their thickness, require a ■ weaker or stronger formaldehyde solution resp. a shorter or longer exposure time. So you put gelatin foils, depending on their thickness, e.g. in a 3 to 5 percent. Formaldehyde solution for a quarter of an hour to an hour, very strong even up to two hours. After drying, these panels have or Foils the desired texture.

Such plates, foils etc. are also protected against mold growth in warm, humid air and insensitive to contact with damp, warm hands.

So you can also harden photographic drying plates, which are known to be photosensitive Substance z. B. may contain silver bromide. For this purpose they are bathed in one weak formaldehyde solution, which, in contrast to the method according to D. R. P. No. 51407 lets dry on the plate, without rinsing with water beforehand. After drying, the gelatin layer is hard and resistant, so that such plates can also be used in warm photographic applications Solutions are stable and do not suffer even at higher temperatures. This condition is of great importance in warm seasons and in hot countries.

Following the procedure of D.R.P. No. 51407 Formaldehyde is said to be used to increase the photosensitivity of drying plates by rinsing the plate in a formaldehyde solution, causing the formation of poorly soluble or insoluble formaldehyde gelatin is prevented. A hardening or Insolubilization of the gelatin layer is neither intended nor after Process achieved because the formation of water-insoluble gelatin, which according to the present Invention is to take place, includes the increase intended according to D.R.P. No. 51407 der.sensitivity to light. The intended result in one process so cannot be achieved with the other method. How many times. Attempts result have, the. insoluble formaldehyde gelatin only if either concentrated formaldehyde solutions are used, or when applied weaker formaldehyde solutions do not rinse off the gelatin layer before drying will.

Claims (2)

Patent Claims: 1. Method of making in warm respectively hot water insoluble or very sparingly soluble gelatine plates or Films, consisting in that formaldehyde, in gaseous form or in solution, is applied to the Allow plates or foils to act. 2. Manufacture of photographic gelatin dry plates, consisting in that one the drying plates in the manner characterized by claim 1 subject to the fact that, in contrast to the or. achieved Purpose insoluble or poorly soluble formaldehyde gelatine is formed.