US2346078A

US2346078A - Antihalation protective layer

Info

Publication number: US2346078A
Application number: US420088A
Authority: US
Inventors: Gale F Nadeau; Richard F Miller
Original assignee: Eastman Kodak Co
Current assignee: Eastman Kodak Co
Priority date: 1941-11-22
Filing date: 1941-11-22
Publication date: 1944-04-04
Anticipated expiration: 1961-04-04
Also published as: FR956731A

Description

April 1944- G. F. NADEAU ETAL ,346,078

ANTIHALATION PROTECTIVE LAYER Filed Nov. 22, 1941 LS/ON.

F/LM SUPPORT.

PERMEABL E ANT/HAL A T/ON L14 YER PROTECTIVE LAYER 0F CELLULOSE ORGAN/C A CID ESTER.

GALE E/YADEAU R/CHARDEMLLER IN VEN TORS BY 4% M ATTORNEYS Patented Apr. 4, 1944 1 2,346,078 ANTIHALATION PROTECTIVE mm Gale F. Nadeau and Richard F. Miller, Rochester, N. Y., assignors to Eastman Kodak Company, Rochester, N. Y., a corporation of New Jersey Application November 22, 1941, Serial No. 420,088

6 Claims.

This invention relates to photographic antihalation film and more particularly to antihalation film carrying a protective layer for the anti halatlon layer.

One problem in connection with coating antihalation backing layers onto photographic films, is the tendency for the dyes to bleed or difluse from the layer into adjacent layers, such as emulsion layers, when film is wound on a spool or several sheets of film are placed one upon the other. One method for overcoming this difiiculty has been disclosed in the Nadeau and Slack U. S. Patent No. 2,326,057, granted August 3, 1943, and consists in converting the dye and the carrier material of an antihalation layer to a less water soluble salt through the use of slightly soluble or insoluble organic amines.

We have discovered a superior method of overcoming this bleeding tendency of antihalation dyes, which consists in overcoating the dye layer with a protective layer of cellulose organic acid ester permeable to photographic processing solutions. It is not always suflicient to coat such a layer from solvent solutions chosen at random, for in some instances with improper solvents, the dye may be carried into the back oi. the film support or may be redistributed into the protective layer itself. In the preferred embodiment of our invention, a solvent is chosen for coating the protective layer which has a minimum attack on the vehicle of the antihalation layer, and in which the light-absorbing material is not appreciably soluble.

The accompanying drawing shows in cross-sectional view a photographic film constructed in the manner of the invention;

In the drawing, a film support l0, which may be a cellulose ester, synthetic resin or similar material, carries a sensitive emulsion layer II, on one side, or a multiplicity of difierently sensitized emulsions which may also be colored with dyes bleachable under influence of silver, and on the other side an antihalation layer ll, of cellulose organic acid ester, containing fugitive dyes, permeable to photographic processing solutions, and over which is the protective layer l3 of the invention, which may either be only permeable to, and not soluble in, photographic processing solutions, or it may be both permeable and soluble in said solutions.

- Our invention is better understood by consideration of the following examples which are only illustrative of the numerous modifications and equivalents of which our invention is capable,

and are not intended to limit the scope of the invention.

Example I A photographic film support of cellulose acetate propionate or cellulose nitrate suitably subbed if desired as shown in Examples 1 and 4 of Nadeau and Slack U. S. Patent 2,289,799, granted July 14, 1942, may be coated with a dope of the fol lowing typical composition.

Per cent Cellulose acetate phthalate (27 per cent acetyl, 13 per cent phthalyl) 4.5 Acetone 45 Methyl Cellosolve 20 Ethanol 30.5

overcoated with a thin layer of cellulose acetate phthalate of the same composition, although it need not be the same, as used in the antihala tion layer, usingthe following formula:

Per cent Cellulose acetate phthalate 1.5 Ethyl acetate (13% ethanol) 98.5

In the above formula pure ethyl acetate, or the commercial grade indicated, containing some ethyl alcohol, may be used to the extent that the dye layer is not adversely affected. The amount of a dye solvent, such as alcohol, which may be tolerated, is dependent upon the dye density in the antihalation layer. Thus when the density is such that only antihalation protection is provided, an appreciable amount may be tolerated, however, if a greater density of dye is required, as for instance, to give adequate leader protection for daylight loading'of film, then the degree of activity of the solvent must be reduced. Generally, about 10-15% of active dye solvent may be tolerated.

. Example II The antihalation layer, of a film of the type described in Example I suitably subbed if desired and coated with cellulose acetate phthalate, may be tinted with a solution containing about parts of ethyl alcohol, 10 parts of water and about 1.5 parts of a fugitive dye such as Acid Magenta (800), Acid Green (764), Acid Blue 3R, Luxol Brilliant Green BL (guanidine salt of Acid Green) or sulfonated Malachite Green. In addition. the dye solution may contain a surface-active agent such as Aerosol AY (sodium suli'o diamyl succinate) in the amount of about 1-5 per cent. Over the dye layer is applied a 5 per cent solution of cellulose acetate phthalatein a mixture of 94 parts of ethylene chloride and 6 parts of alcohol. In a similar manner our invention may be applied to other suitable photographic fllm supports of materials such as synthetic resins, cellulose esters, as for instance, cellulose acetate, cellulose propionate, etc., celluose mixed organic acid esters, e. g., cellulose acetate propionate, cellulose acetate butyrate or cellulose nitrate. These supports may carry a suitable antihalation layer of a material preferably only permeable to photographic processing solutions, however, antihalation layers soluble in photographic processing solutions may be used if desired, in which case a light-absorbing material, such as carbon or a non-fugitive dye may be used.

Antihalation layers of the preferred type comprise the cellulose organic acid dicarboxylic acid esters disclosed in Nadeau and Slack U. S. Patent 2,311,073, granted February 16, 1943, that is, cellulose esters containing substantially 4-8 acyl groups per C14 cellulose unit of which not more than one is a dicarboxylic acid acyl group and the remainder are monobasic acid groups. Such esters are permeable to, but not soluble in, photographic processing solutions such as a developer. In addition, the cellulose monobasic organic acid esters disclosed in the same patent application may be used. Similarly, materials soluble in photographic processing solutions, as for instance, the alkali soluble cellulose organic acid dicarboxylic acid esters disclosed in the Nadeau and Slack U. S. Patent 2,289,799, above cited, may be employed. In applying the antihalation layers to film supports the methods shown in the abovecited applications may be used.- Other antihalation layers containing resin vehicles, such as disclosed in the Nadeau and Slack U. S. Patent tains another cellulose organic acid dicarboxylic acid ester of difi'erent composition, or a partially hydrolyzed cellulose monobasic organic acid ester of the composition shown in the application cited immediately above. In this case it is necessary to choose a solvent which will adhesively join the ester of the protective layer to the antihalation layer and at the same time will not adversely aflect the dye distribution in the antihalation layer. This is more difiicult than in the case where the two layers contain the same cellulose ester.

Other cellulose esters useful in the protective layer are alkali soluble cellulose organic acid dicarboxylic acid esters such as those disclosed in U. S. Patent 2,289,799 above cited in which case non-fugitive dyes or carbon may also be used in th antihalation layer. It is, therefore, obvious that from the materials useful in the protective layer of our invention may be chosen cellulose esters only permeable to photographic processing solutions, or both permeable and soluble in said solutions.

There are numerous variations of our methods which assist in attainment of the utmost in prevention of dye bleeding and which maybe used in conjunction with the protective layer of the invention. For instance, if desired, as disclosed in the Nadeau, Slack, and Smith, U. S. patent application, Serial N0. 415,590, filed October 18,

1941,"to the antihalation layer or protective layer coating solutions may be added surface-active agents to promote penetration of processing solutions. Also, as disclosed in the Nadeau and Slack U.- S. Patent 2,326,057, varicus amines such as dioctyl amine or toluidine, may be used to form'salts with the dyes and carrier materials to aid in the fixation of the dye in the antihalation layer.

It is to be understood that the disclosure herein is by way of example and that we consider as included in our invention all modifications and equivalents falling within the scope of the appended claims.

What we claim is:

l. A light sensitive photographic film comprising a support carrying a silver halide emulsion layer on one side thereof, on the other side an 2,319,080, granted May 11, 1943, may be provided so antihalation layer of cellulose organic acid ester with the protective layers of the invention if suitable solvent solutions are used.

Films provided with antihalation layers in this manner are now susceptible to application of the protective layer of the invention. Materials preferred for use in this layer are the cellulose organic acid dicarboxylic acid esters and the cellulose monobasic organic acid esters, such as those disclosed in Patent 2,311,073, above cited, having substantially 4-8 acyl groups per C24 cel lulose unit of which not more than one is a dicarboxylic acid acyl group and the remainder are monobasic acid acyl groups. As previously mentioned, one chooses a solvent solution for the cellulose ester which has a minimum of attack on the vehicle of the antihalation layer and in which the antihalation dye, or dyes, is insoluble or not appreciably soluble. Solvents of the type useful when the antihalation layer and the propermeable to, but not soluble in, photographic processing solutions, and over the antihalation layer a protective layer of cellulose organic acid dicarboxylic acid ester permeable to photographic processing solutions.

2. A light sensitive photographic film comprising a support carrying a silver halide emulsion layer on one side thereof, on the other side an antihalation layer of cellulose organic acid ester permeable to, but not soluble in, photographic processing solutions, and over the antihalation layer a protective layer of cellulose organic acid dicarboxylic acid ester permeable to, but not soluble in, photographic processing solutions and coated from a solvent solution in which the lightabsorbing material of the antihalation layer is not appreciably soluble.

3. A light sensitive photographic film comprising a, support carrying a silver halide emulsion tective layer contains cellulose organic acid dilayer on one side thereof, on the other side an carboxylic acid esters are. shown in the preceding examples.

The method is not quite so simple if the antihalation layer and the protective layer contain antihalation layer of cellulose organic acid ester permeable to, but not soluble in, photographic processing solutions, and over the antihalation layer a. protective layer of cellulose organic acid different cellulose esters, e. g., if either layer con- 16 d ar xy acid ester having substantial y 4-8 acyl groups per C24 cellulose unit of which not more than one is a dicarboxylic acid acyl group and the remainder are monobasic acid acyl groups coated from a solvent solution in which the light-absorbing material of the antihalation layer is not appreciably soluble.

4. A light sensitive photographic film comprising a support carrying a silver halide emulsion layer on one side thereof, on the other side an antihalation layer of a cellulose organic acid dicarboxylic acid ester having 4-8 acyl groups per C24 cellulose unit of which not more than one is a dicarboxylic acid acyl group and the rest are monobasic acid acyl groups, and over the antihalation layer a protective layer of a cellulose organic acid dicarboxylic acid ester having 4-8 acyl groups per C24 cellulose unitof which not more than one is a dicarboxylic acid acyl group and the rest are monobasic acid acyl groups coated from a solvent solution in which the lightabsorbing material oi the antihalation layer is not appreciably soluble.

5. A light sensitive photographic film comprising a support carrying a silver halide emulsion layer on one side thereof, on the other side an antihalation layer of a cellulose organic acid ester permeable to, but not soluble in, photographic processing solutions, and over the antihalation layer a protective layer of a cellulose organic acid dicarboxylic acid ester soluble in photographic developing solutions. a

6. The method of providing a sensitive antihalation photographic film with a protective layer for an antihalation layer of a cellulose organic acid ester permeable to, but not soluble in, photographic processing solutions, which comprises coating said layer with a layer of cellulose organic acid dicarboxylic acid ester permeable to, but not soluble in, photographic processing solutions from a solvent solution in which the lightabsorbing material of the antihalation layer is not appreciably soluble.

GALE F. NADEAU. RICHARD F. MILLER.