US2089460A - Process for fastening a photographic material on a support and the resulting product - Google Patents

Description

1937- G. WILMANNS ET AL 2,089,460

' PROCESS FOR FASTENING A PHOTOGRAPHIC MATERIAL ON A SUPPORT AND THE RESULTING PRODUCT Filed Jan. 31, 1954 liq/2t sensitive Jaye?" support layer or dggradedgedatm, degraded ar-a ar or degraded casein aolub e m the cold r gid a upport 1 a ATTORNEYS Patented Aug. 10, 1937 UNITED STATES PATENT OFFICE PROCESS FOR FASTENING A PHOTOGRAPH- IC MATERIAL ON A SUPPORT AND THE RESULTING PRODUCT Application January 31, 1934, Serial No. 703,196'

In Germany February 15, 1933 f 2 Claims.

5 Further objects will be apparent from the detailed specification following hereafter.

The accompanying drawing shows a fragmentary diagrammatic sectional view upon an exaggerated scale of a photographic material attached to a rigid support in accordance with the invention.

It is known that photographic films may for a short time be fastened to a porous rigid support by use of a vacuum. This process, however, is costly and complicated. At present films are generally fixed to rigid supports by using the socalled adhesive gelatin which is cheap but involves various drawbacks. Thus the support must carefully be levelled before the application of the solution of adhesive gelatin. The casting solution, when in a condition ready for use, is

stable only for a short time and dries slowly; for

this reason itis impossible to use immediately the layer of adhesive gelatin applied on the support and while it is drying, the layer may become soiled by dust. I

According to U. S. Patent 2,010,188 of Hagedorn et al., an adhesive medium is used which is constituted by a layer of polymerization products of unsaturated aliphatic compounds, the sticking power of which has been largely reduced by the addition of a softening agent, a filling material or a derivative of carbohydrates.

According to the present invention we have found'that the process is considerably improved by using degraded gelatin or another degraded albuminous colloid, for instance, agar-agar 0r casein the degradation being such that the colloid is soluble in the cold and using as a solvent for 49 the colloid an organic solvent of such volatility that the layer dries rapidly and thus permits the use of the support nearly immediately after the colloid layer has been cast thereon. Suitable solvents are, for instance, glycolmonoacetat'e, ethylacetate and dioxane which. are all used in admixture with water. The most suitable amount can easily be determined by experiment and may be up to 50 per cent. As agents suitable for the 50 degradation of the colloid we enumerate, for instance, chloralhydrate, potassium thiocyanate and papain. The degradation is effected by heating the colloid with one of the aforesaid agents generally to a temperature between and C.,

according to the degrading agent which is used.

The duration of treatment is of minor importance; 3 to 5 minutes may already be suilicient. However, we do not wish to limit the invention to the given values of temperature and duration, considerable changes being possible. The adhesive power of our new adhesive material is enhanced by addition of glycerin.

As compared with the ordinary adhesive gelatin which mostly consists of a gelatin solution of about 15 per cent. strength having an addition of about 50 per cent. of glycerin the adhesive agent according to this invention shows the advantage that, as it has already been pointed out, the supports on which it is cast may be used much sooner. The adhesive liquid may be applied to the levelled supports and allowed to dry thereon, in the manner known for the adhesive gelatin hithereto in use or it may be poured on the support and the surplus amount then run oiT, whereupon the remaining thin layer is caused or allowed to dry. The film is squeezed on to the dry adhesive layer. This structure is adapted for handling, for instance, for use in taking pictures as well as for treatment in liquids. The sticking power is not afiected by the photographic baths and the plates may repeatedly be used. By the addition of a suitable agent the adhesive liquid acquires an increased stability as compared with the known adhesive gelatin. Such stabilizing agents which simultaneously may assist the dissolution of the degraded gelatin are the organic acids, for instance, phthalic acid, acetic acid and salicylic acid.

- The following examples illustrate the invention:

Example 1.A photographic film is for exposure and/or development pressed on a plate glass disk which bears an adhesive layer produced from the following solution:

40 grams of gelatin are dissolved in a mixture of 25' grams of water, 30 grams of ethylenechlorhydrine, 95 grams of methanol and 5 grams of phthalic acid while heating.

To this mixture there are added 30 to 50 grams of glycerin and the whole is heated to 90 to C. for 3 to 4 hours. The solution obtained remains liquid when cold and may be diluted with methanol or the like according to requirement. In this example the gelatin may also be exchanged for any other colloid.

Example 2.--Instead of the solution of adhesive gelatin described in Example 1 there is used a solution of 100 grams of water,

25 grams of gelatin,

9 grams of chloral hvdrate and 20 grams of glycerine which has been heated to about 40 C., for about 3 to 5 minutes.

Example 3.-The adhesive layer for temporarily attaching a. photographic material to a rigid support is made by casting and drying the following solution:

75 grams of water 75 grams of gelatin cc.v of 2=n=solution of borate having pBi=5.8

are kept for 2. hour at 20 to C. and then fil tered. After the addition of the papain solution the casting solution is kept at to C. for about 3' to 6 hours or even longer according to the brand of gelatin used. v

By addition of finely divided agents, for instance, S1102, BaSOr or SiOz-hydrate, the adhesive layer may be given a matt surface.

What we claim is:

1. In combination a rigid support and attached thereto by means ofa compound selected from. the group consisting of degraded gelatin degraded agar-agar and degraded casein soluble in the cold, a photographic material comprising a support and a light sensitive layer attached to said support.

2. In combination a rigid support and attached thereto by means of degraded gelatin soluble in the cold, a photographic material comprising a support and a light sensitive layer attached to said support.

GUSTAV WJIMANNS. 1 GERHARD v. KUJAWA.

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