US2083640A - Photographic stripping film - Google Patents

Description

June 15, 1937. R coucgH ET AL 2,083,640

PHOTOGRAPHIC STRIPPING FILM Filed Dec. 6, 1954 7 Swan/v5 [Mum/0M 5 T/NESUBSTPATUM 4 NITRATE SUPPORT (/IYDROLYZED CELLULOSE ACETATE) NITPATE Arms/v5 SrP/PP/Nc LAYER BAPYTA Char/Ne YEMPORARYSUPPURTK 001/51: WEIGH TPAPER) amnion HezzzyE (budmmfll welk dbfonw 1 Patented June 15, 1937 rno'roomrmc s'rmrrmo FILM Henry R. Couch and John H. Folwell, Rochester, N. Y., assignors, by mesne assignments, to Eastman Kodak Company, Jersey City, N. J.

a corporation of New Jersey Application December 6, 1934, Serial No. 756,294

5 Claims.

This invention relates to a stripping film and particularly to such a film involving an im proved adhesive layer and in which the stripped film may be readily applied, with either surface up, to a second support after removal from the first temporary support. In certain aspects, this invention is an improvement over the stripping film described in the U. S. patent of C. R. Fordyce and M. Salo, No. 1,973,476, granted September 11, 1934.

The material is particularly intended for use in making cuts for newspaper work where high speed is desired, although it is capable of use for any other purpose where stripping film is ordinarily used. In particular, a permanent support of a hydrolyzed cellulose ester, such as is described in the said Fordyce and Salo patent, is used having on one side a photographic emulsion layer and on the other side a very thin cellulose nitrate layer, which has better adherence to glass than the hydrolyzed ester of the permanent support. This permits the stripped film to be placed either side up on glass. In use in newspaper work the stripped film will be cut into the desired shape and diiierent pieces by known methods.

of film from other points may be fitted together, either side up, to make a composite picture. After the whole is assembled the composite picture may be used for printing directly upon metal This is a much easier process than joining various pieces of original photographic film negatives and eliminates the necessity of rephotographing or reprinting some objects, or negatives through the film to reverse them. Another advantage is that, after a print is made, all or a part may be readily stripped from the glass and used again, or another piece substituted for it.

Reference is made to the accompanying drawing, the single figure of which shows on an exaggerated scale a section of film embodying our invention.

The layer l is a temporary support of paper which may be water permeable or non-permeable,

usually of double weight stock such as is used for stiff unmounted photographs or photographic post-cards. This may be previously coated with a glossy baryta coating la. Over this is coated a layer 2 of adhesive material which should be.

readily soluble and free from craze or cracking when dry. We have found that equal parts of readily soluble glue of good quality and of glycerine make a satisfactory layer. This is dissolved in water with preferably about 25 to 30 parts of the above ingredients to 75 to '70 parts of water and this is coated on the paper and dried, or at least permitted to set, before the next coating is applied. The amounts of glue and glycerine should be of the same order, that is, the amount of glycerine should be at least one third of the amount of glue, but the exact proportions of these and of the water are not at all critical. Salicylic acid or thymol may be used as a'preservative for the glue in the amount of approximately one tenth of one per cent of the weight of glue.

The methods of coating the various layers would be those common in regular photographic coating operations, the paper web being passed in succession past known coating devices such as hoppers, or immersion rolls, and being dried or conditioned between successive operations under controlled air conditions.

Over the adhesive layer 2 is applied a very thin layer 3 of cellulose nitrate, applied for instance from the following solution:

Cellulose nitrate parts by weight-.. 2.5 Glyceryl boriborate do 1.25 Methyl alcohol parts -90 Butyl alcohol do 40-10 this layer having preferably a thickness of the order of one ten thousandths to one hundred thousandths of an inch. The glyceryl boriborate renders the nitrate layer more permeable to water. Other materials having the same effect may be used, such as sugar, glycerine, dextrine, lactic acid, mono-acetin, di-acetin and triacetin. While it is quite possible to use a thin cellulose nitrate layer without the addition of a material to increase its water permeability, we prefer the addition of a high boiling, water soluble material of the type mentioned which is compatible with cellulose nitrate and increases its water permeability. There is then applied a thicker layer 4 of hydrolyzed cellulose acetate, or the equivalent, as fully described in said Fordyce and Salo patent, and there may then be applied a nitrate layer 5 similar to layer 3 followed by a thin gelatin sub-layer 6 and finally the sensitive emulsion layer 1. After passing through a drying chamber the web is wound on a, roll and subsequently cut into sheets of the desired size.

We contemplate as included within our invention such modifications and equivalents as fall within the scope of the appended claims.

Having thus described our invention, what we claim as new and desire to secure by Letters Patent is:

1. A stripping film comprising a photographic layer, a support to which the photographic layer is permanently attached, a temporary support and a water soluble adhesive layer between the temporary and permanent supports comprising glycerine and readily water soluble glue, the proportions of glycerine and glue being of the same order, the permanentv support carrying also a permanently adherent very thin layer of cellulose nitrate between itself and the adhesive layer.

2. A stripping film comprising a paper support, a soluble adhesive layer comprising a mixture of glycerine and of glue readily soluble in'water and a stripping element detachable from the support and including a water-permeable supporting layer of hydrolyzed cellulose acetate having-on its outer surface a sensitive emulsion and, between the adhesive layer and cellulose acetate layer, a

very thin layer of cellulose nitrate permanently adherent to the cellulose acetate layer.

3. A stripping film comprising a photographic layer, a support to which the photographic layer is permanently attached, a temporary support and a water soluble adhesive layer between the temporary and permanent supports comprising glycerine and readily water soluble glue, the proportions of glycerine and glue being of the same order, the permanent support carrying also a permanently adherent very thin layer of cellulose nitrate between itself and the adhesive layer, the nitrate layer including a material increasing the water permeability of the layer.

4. A stripping film comprising a photographic layer, a support to which the photographic layer is permanently attached, a temporary support and a water soluble adhesive layer between the temporary and permanent supports comprising glycerine and readily water soluble glue, the proportions of glycerine and glue being of the same order, the permanent support carrying also a permanently adherent very thin layer of cellulose nitrate between itself and the adhesive layer, the cellulose nitrate layer including a high boiling, water soluble material which is compatible with cellulose nitrate and increases the water permeability of the layer.

5. A stripping film comprising a permanent support, a readily soluble water adhesive layer thereon, and a stripping element including a water permeable supporting layer of a hydrolyzed cellulose acetate having on its outer surface a sensitive emulsion and, between the adhesive layer and the cellulose acetate layer, a very thin layer-of cellulose nitrate permanently attached to the cellulose acetate layer and including a high boiling, water soluble material which is compatible with cellulose nitrate and increases its water permeability.

HENRY R. COUCH. JOHN H. FOLWELL.

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