US2169004A - Low dye retention sub for photographic film - Google Patents

Description

g- 1939- G. F. NAD EAU' 2,169,004 I LOW DYE RETENTION SUB FOR P HQTOGRAPHIC FILM Filed Odt. 21, 1958 Fig.1.

V EMULSION G'ELAWN CELLl/LOSEN/TRATEAND .SVNTHETIC'RESIN NOT CON7i4/N/NG' A CARBOXYL GROUP w 10 fi'fCELLULOSE DERIVATIVE SUPPORT 14 EMULSION 13 K 6'ELAT/N l v, CELLULOSE N/TRATE AND 1/ POLYVINYL ACETATE JJ fi h)" CELLULOSE ORGAN/C DERIVATIVE SUPPORT F 19. 5. 18 I 5w: SENSITIVE EMULSION EEN SENSITIVE EMULSION o SENSITIVE EMULSION v GELAT/N I CELLULOSE NIT/Z475, AND SYNTHETIC RES/N? 11 NOT co/vm/rmya A CARBOXYL GROUP wn nap cm umf'oRcAN/c DER/I44 TIVE suPPom Patented Aug. 8, 3&39

' UNITED STATES LOW DYE aE'rEN'rioN SUB FOR Pno'roGaArnIc FILM Gale F. Nadeau, Rochester, N. Y., assignor to Eastman Kodak Company, Rochester, N. Y., a corporation of New Jersey Application October 21, 1938, Serial No. 236,265

12 Claims.

This invention relates to a method for subbing photographic film and particularly to a sub for film designed to receive a colored photographic image.

The problem of producing a photographic safety film base possessing satisfactory stripping and brittleness qualities has been an extremely difiicult one. In order to cause photographic emulsion layers to adhere to cellulose organic acid b ester supports, it is necessary to use intervening layersof such character that the several layers do not strip from the support when the film is used or when it is passed through processing baths and also of such character that the layers i do not adhere with such firmness that the film becomes brittle. One successful way of making a photographic film having satisfactory stripping and brittleness properties is to use a synthetic resinous material as a sub or undercoat, as described in my prior application Serial No. 1547.

In the case of photographic film having an emulsion layer or several emulsion layers designed to receive, colored photographic images, the subbing or undercoat layers must possess additional 5 qualities. The dye or other coloring material used in the emulsion layers is likely to stain the sub or undercoat if it is not properly constructed and the sub or undercoat may also cause fading of the dye in the emulsion layer of the film next to the sub, when the film is incubated or stored after processing.

It is, therefore, an object of the present invention to provide a sub or undercoat for a photographic safety film having an emulsion layer or layers designed to receive colored images, which does not retain a dye "stain caused by the colored image. A further object is to provide a subbing layer which does not cause the dye in an overcoat emulsion layer to fade or bleach during storage of the finished film. A still further object is to provide a safety film having satisfactory stripping and brittleness characteristics. Other objects will appear from thefollowing description of my invention.

,, These objects are accomplished according to my invention by providing a subbing layer of a mixture of cellulose nitrate and a synthetic resin not containing a carboxyl group. The layer is coated directly on a cellulose organic acid ester film base and other suitable layers are coated over it.

3 In. the accompanying drawing Figs. 1, 2 and 3 are sectional views of a photographic film having subbing layers thereon according to my inven- In subbing film according to my invention a cellulose derivative support of any composition is coated with the subbing or undercoat layer of cellulose nitrate and the synthetic resin. The support may consist of cellulose nitrate or other 5 inorganic acid ester of cellulose, but a cellulose organic acid ester will ordinarily be used with a sub of this type. The cellulose organic derivative support may be a simple ester, such as cellulose acetate or a mixed ester, such as cellulose acetate l0 propionate or cellulose acetate butyrate. I

The subbing layer first applied consists of a uniform mixture of a high alcohol soluble, low viscosity cellulose nitrate and a synthetic resin not containing a carboxyl group. I have found that the resins containing carboxyl groups are not suitable for subbing according to'my invention since they tend to stain and, therefore, render'the film unfit for use as coior film. Among the synthetic resins which may be used are the following. The polyvinyl esters, such as polymer ized vinyl acetate which is known, for example, under the trade name Gelva, the preparation of which is described in the U. S. Patent Nos. 1,241,738; 1,586,803 and 1,710,825. A further type of resin which may be used is the polyvinyl acetal type. These resins are condensation products of partially or completely hydrolyzed polyvinyl acetate and an aldehyde, such as formaldehyde, acetaldehyde, or butyraldehyde and are known as polyvinyl acetals. They are sold under various trade names such as Formvari and Alvar, the preparationof which is described in British Patent No. 351,082 and in U. S. Patents Nos. 1,955,- 068 and 1,990,399. A still further type of resin is the group known as the Santolites which are condensation products of formaldehyde with aromatic sulfonamides. I may also use the polyacrylic esters, such as the methyl or butyl esters of polyacrylic acid. 49

After drying, the layer of cellulose nitrate and synthetic resin may be coated with a cellulose nitrate layer other layer or a gelatin layer may be coated directly on it. The gelatin layer is fol lowed by a coating of one or more emulsion layers 5 designed to record a colored photographic image.

My invention will now be described by particular reference to the accompanying drawing. As shown therein a support ID of any suitable material such as cellulose nitrate or cellulose acetate o is coated with a layer 12 of cellulose nitrate and a synthetic resin not containing a carboxyl group.

On this layer there is coated a gelatin layer l3 and a gelatino-silver halide emulsion layer It.

According to the modification shown in Fig. 5b

2 a support ll of an organic acid ester derivative of cellulose, such as cellulose acetate or cellulose acetate propionate, is coated with a layer I5 of cellulose nitrate and polyvinyl acetate. 3 This layer is then coated with the gelatin subbing layer i 3 and emulsion layer M.

Fig. 3 shows a film designed for multi-color photography in which the support II is coated with the subbing layer l2 of cellulose nitrate and a synthetic resin not containing a carboxyl group, and this is followed by the, gelatin layer l3. On the gelatin layer I3 are coated in succession a red sensitive silver halide emulsion layer IS,

other layers, such as intermediate filter layers,

which may be necessary to prevent the action of light of any spectral color on any of the layers of 4 the film.

As stated above, the subbing layer applied directly to the film base consists of a mixture of cellulose nitrate and a synthetic resin not containing a carboxyl group. The cellulose nitrate is of the high alcohol soluble, low viscosity type which may have the following composition:

. Range Alcohol solubility per cent 30-100 Viscosity (dropping ball) sec 2-5 Nitrogen 11.0-12.0

The resin and nitrate undercoat is coated on the film base from a suitable solvent or solvent mixture, such as acetone, acetone and methanol;

acetone and methyl alcohol, ethylene dichloride with methyl alcohol or ethyl alcohol, and various combinations o1 these solvents together with methyl Cellosolve. A suitable solvent mixture consists of 40 parts acetone and parts of methyl alcohol. I

The concentration of the subbing solution adjusted to the speed of coating and may vary 'fromabou't 2% to about 6% or more of nitrate and resin in the solution. The sub is coated at a linear speed of from 3 to 10 feet per minute and a layer which may vary in thickness from 0.00006 inch to 0.00015 inch is thereby obtained.

The gelatin --sub coated over thenitrate-resin layer may have the following composition:

- Per cent Gelatin -'1.2 Acetic acid 2 Water 12 Methyl alcohol "-84.8

The emulsion layer coated over the gelatin sub may consist of an ordinarygelatinosilver halide emulsion or it may be sensitized to record various regions of the spectrum. In the case of multilayer iilm, the successive emulsion layers applied to the gelatin sub may be differentially sensitized and may or may not contain dyes or color forming compounds designed to produce a colored photographic image or images in the layers. The

film may also have other layers, such as filters,

' overcoating layers, or 'anti'-halation1 layers applied thereto.

My invention will be further understood by reference to the following specific examples which are understood to be illustrative only.

Example I A photographic film base of cellulose acetate containing about 40.5% acetyl was coated with the following subbing solution:

Grams Polyvinyl acetate 1.2 Cellulose nitrate 1.2 Acetone 38.8 Methanol--- 58.8

This solution was coated at a linear speed of 6 feet per minute and was dried after coating. A gelatin subbing layer having the following composition was then applied:

Per cent Gelatin 1.2 Acetic acid 2 Water 12 Methyl alcohol 84.8

Over the gelatin layer there was then coated a gelatino silver halide emulsion layer. The film produced in this way was found to have satisfactory stripping and brittleness properties and when a colored image was formed in the sensitive emulsion layer,- the dye was not retained by the subbing layer.

. Example I! A photographic film base of cellulose acetate 'propionate containing 16% propionyl and 29% acetyl was coated with, a subbing solution having the following composition:

Grams Polymethyl acrylate 2 Cellulose nitrate 4.6 Acetone 93.4

After drying, there was coated on this layer a solution of gelatin having the same composition as that in Example I and successive layers of red green sensitive layer and the red sensitive layer.

'Ihave referred to satisfactory stripping and brittleness properties" throughout the specification. It is to be understood that this term, although not susceptible of precise definition, nevertheless has a definitely accepted meaning in the photographic art, and that film can be tested to determine whether it is commercially satisfactory with respect to stripping and brittleness. Tests to which the film may be subjected for this purpose are outlined in my prior U. S. Patent No. 2,096,616, granted October 19, 1937.

I have also referred above to the "dropping ball method" for determining the viscosity of cellulose nitrate. The "dropping ball method" for iletermining viscosity oi. cellulose nitrate is as-folows:

110 grams 01' dry nitro cellulose is dissolved in cc. oi a mixture comprising 50% by volume of methyl alcohol and 50% by volume of acetone at -25 C. Viscosity is measured by the time in seconds it takes for; a steel ball having a dive'ntion has a number 01' important advantages.

tain-any dye which is used in the emulsion layers to form color photographic images and does not cause fading of the dye contained in these layers, my subbing method also has other advantages. For example, the mixture of 'i'esin and nitrate can be conveniently handled in coating machines as it is not tacky and does not adhere to the machine parts. The-resulting film is not brittle althoughthe emulsion adhereswell to the base. The wearing qualities of motion picture film made in this way are very good and film was found to be.

in good condition after having been passed through a projector a number of times.

I have referred in the present description of my invention, to subbing safety filmsupport, that is, cellulose organic acid ester film support, as constituting the preferred embodiment of my invention. However, although the problem of sub-' bing cellulose inorganic acid ester supports is usually not so difllcult as in the case of cellulose or-- ganic acid esters,- the matter of staining the sup-' port in color processes must be considered. I

have found that the use of subs according to my invention, prevents dye staining of cellulose nitrate supports as well as supports of cellulose organic acid esters. I

I-have also referred to the use of my subbing method in film designed to receive colored images. Film support may also be subbed according to my invention where the film is designed to record black-and-white silver images.

It is to be understood that the above examples, ranges, and methods of procedure are illustrative only and that my invention is to be taken as limited only by the scope of the appended claims.

Having thus described 'my invention, what I I declare is new and desire to secure by Letters Patout of the United States is:'

1. A photographic film for use in color photography having low dye retention subbing layers, comprising acellulose ester support, an emulsion layer adaptedto receive a colored image, and between said support and said. emulsion layer, a subbing layer of a mixture of cellulose nitrate and a synthetic resin free of carboxyl groups.

2. A photographic film for use in color photography having low dye retention subbing layers,

comprising a cellulose organic ester support, a subbing layer of a mixture of cellulose nitrate and a synthetic resin free of carboxyl groups directly attached to said support, a gelatin layer attached to said subbing layer, and an emulsion layer adapted to receive a colored image'attached to said gelatin layer.

3. A photographic film for use in color photography having low dye retention subbing layers, comprising af cellulose organic acid ester support, and in order thereon, a subbing "layer of a. mixture of cellulose nitrate and a synthetic resin tree of carboxyl groups, the resin in the sub being present in not greater amount than the cellulose nitrate, a gelatin layer, and an emulsion layer adapted to receive a colored image.

4. A photographic film for use in color photography having-low dye retention subbing layers, comprising a cellulose organic acid ester support, and in order thereon, a subbing layer of a mixture of cellulose nitrate and asynthetic resin free or 'carbonl groups, the resin and the nitrate being present in substantially equal amounts, at gellatin 5. A photographic film for use in color photography having low dyeretention subbing layers, comprising a cellulose organic acid ester support, and in order thereon, a subbing layer of a mixture of cellulose nitrate and a synthetic resin free of carboxyl groups, a gelatin layer, and a .plurality of diilerentially sensitized emulsion-layers.

. 6. A photographic film for use in color photography having low dye retention subbing layers, comprising a cellulose organic acid ester support, and in order'thereon, a subbing layer of, a mixture of cellulose nitrate and a synthetic resin free of carboxylgroups, the resin and the nitrate being present in equal amounts, a gelatin layer; and a plurality of emulsion layers sensitized to record different regions of the spectrum.

7., A photographic film for use in color photography having low dy'e retention subbing layers,

comprising a cellulose organic acid ester support, and in order thereon, asubbing layer of a mixture ofcellulose nitrate and a polyvinyl acetate resin, a gelatinlayer, and a plurality of emulsion layers sensitized to record diiferent regions of the spectrum. 1 8. A photographic film for use in color photography having low dye retention subbinglayers, comprising a cellulose organic acid ester support,

and in order thereon, a subbing layer of a mixture of cellulose nitrate and a polyvinyl acetate resin, the resin. being present in less amount than the cellulose nitrate, a gelatin layen and a plurality of emulsion layers sensitized to record different regions of the spectrum.

9. A photographic film" having satisfactory stripping and brittleness-properties, comprising a cellulose organic acid ester film support and a sensitive emulsion layer, and between said support and said emulsion layer, successive layers of a mixtureof cellulose nitrate and asynthetic resin free of carboxyl groups, and a gelatin layer.

10. A photographic film having satisfactory stripping and brittleness properties comprising a cellulose organic acid ester support, a subbing layer of a mixture 01' cellulose nitrate and a synthetic resin free of carboxyl groups coated I directly on said support, said subbing layer hav-;

ing a thickness of from 0.00006 inch to 0.00015 subbing layer, and a sensitive emulsion layerattography having low dye retention subbing layers,

comprising a cellulose inorganic acid ester support, a' subbing layer of a mixture of cellulose nitrate and a synthetic resin, free of carboxyl groups directly attached to said support, a gelatin layer attached to said subbing layer, and an emulsiori layer adapted to receive a colored image at: tached to said gelatin layer.

12. A photographic film for use in color photography liaving low dye retention subbing layers, comprising a cellulose nitrate support, and in order thereon, a subbing layer' of a mixture of cellulose nitrate and a synthetic resin free-or carboxyl groups, a. gelatin layer, and a plurality of emulsion layerssensitized to record different 1 inch, a gelatin layer attached directly, to said

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