US2461473A - Gelatin subbing compositions having antistatic properties - Google Patents

Description

Patented Feb. 8, 1949 GELATIN SUBBING COMPOSITIONS HAVING ANTISTATI C PROPERTIES Frank J. Kaszuba, Binghamton, N. Y., minor to General Aniline & Film,,Corporation, New York, N. Y., a corporation of Delaware No Drawing.

This invention relates to photographic film, and more particularly to gelatin subbing compositions having anti-static properties.

Considerable dimculty has been encountered in the manufacture of photographic film due to the accumulation of electrical charges on the film. In one step of the manufacture of photographic film, a film base is coated on one or both sides with a subbing composition which usually consists of a dispersion of gelatin in a. suitable solvent or solvent mixture, so as to facilitate the adherence; or anchorage, of one or more of the photo-sensitive, non-curling or anti-halation layers. When i such a laminate is wound into a tight roll and subsequently unwound, as during a coating operation, considerable static electricity is generated and spark discharges readily occur. li/iairiifestations of these charges are glow discharges which after development of the coated and exposed film show up as black streaks or lines, or as irregular iogged patterns in the emulsion layer. Attempts have been made to overcome static in such laminates by the incorporation of substances into subbing compositions which are electrolytes or possss hygroscopic properties.- The function of these substances is to impart conductivity to the compositions which reduce static charges on a photographic film base during coating of the Application December 17, 1946, Serial No. 716,881

7 Claims. (Cl. 103-135) 2 As suitable examples of aliphatic amides, the following may be mentioned:

For-mamide Diethyl iormamide Methyl ethyl formamide Acetamide Dimethyl acetamide Methylol acetamide Ethylol acetamide Propionamide Dimethyl propionamide N-methyi-N-hydroxyethyl-acetamide These amides are incorporated into any gelatin subbing composition containing gelatin, water, dispersing medium, such as an organic acid, 1. e., acetic acid, and the like, and an organic solvent or a mixture of such solvents. The amount of these amides, which may be employed as an antistatic medium, may; range fromabout 0.5% to 10%, and preferably from 1% to 3%. The gelatin may range from about 0.5% to 1.5%, preferably from about 0.75% to 1.0%, the balance being water, gelatin dispersing medium, and an organic solvent or mixture of such solvents. All proportions are by weight.

The anti-static gelation subbing compositions are prepared by adding the amide to a gelatin dispersion containing gelatin, water, and a dispersing medium, and thereafter adding the dispersion to an organic solventor mixture of such sensitive silver-halide emulsion; non-curl, or antihalation layers. 7

Further objects will appear hereinafter.

These objects are accomplished by the present invention by incorporating, into any gelatin subbing composition, an aliphatic amide of the following general formula:

solvents, or by adding the amide to the finished gelation subbing composition, 1. e., containing the organic solvent or mixture thereof. Slight warming and agitation will facilitate the dissolution of the amide. The solution thus obtained is depos ited on one or both sides of a film base in any convenient manner, the subbing operation preferably being carried out in connection with, or as -a part of, the process of making the film-support itself. The gelatin subbing solutions made up as above-"described are clear dispersions.

The film-bases used in accordance with this invention are the cellulose derivatives, e. g., cellulose nitrate, cellulose acetate, and other lower fatty acid esters of cellulose including simple and mixed esters, such as celluose propionate, cellulose butyrate, cellulose acetate-propionate, cellulos acetate butyrate, and the like, ethers of cellu- T lose, such as the ethyl ether, benzyl ether, and the like, and the fusible, water-insoluble, synthetic linear superpolymers used for film elements as described inUnited States Patents 2,071,250-2-3 and 2,130,948. v It will be appreciated that each 'diflerent' type of cellulose ester, ether, and mixtures thereof, in-

cluding. the synthetic linear superpolymers, requires a slightly different solvent or solvent combination. The solvent or solvent mixture employed must be such that it will have a solvent or at least a softening or swelling action on the film base so as to stick or anchor the gelatin upon the area of the support which has been softened or swollen. For example, with a cellulose acetate base a low molecular weight alcohol, e. g.. methanol, ethanol, and-the like, or a ketone, such as acetone or a mixture of 3 parts alcohol to one part of acetone may be employed. With cellulose ace- .tate-propionate film base, an alkyl ester, such as,

it be an organic acid, heterocyclic nitrogenous.-

base, lactone, or the like, disperses the gelatin in water, and the solvent or solvent mixture wets or After the subbing layer had dried, the usual l Bht-sensitive emulsion layer was coated directly thereon. Durlngthe coating of the llIht-sensitive emulsion upon the subbed base no static electricity was generated. After exposure and processing the emulsion adhered tenaciousiy to the cellulose acetate film support, and the developed film showed no black streaks or lines.

Example III A film base prepared from poly (vinyl chloridevinyl acetate) was coated with the following subbing composition:

Gelatin 0.5

Water 2.5 Acetic aci 1.5 Dim'ethyl formamide. 1.5 Methanol 32.0 Acetone 62.0

After the subbing layer had dried, the usual light-sensitive emulsion layer was coated directly thereen- During the coating of the light-sensitive emulsion upon the subbed base no static I electricity was generated. After exposure and bites into the cellulose derivative or other materials employed as a film base. The term gelatin dispersed in a solvent for saidsupport as used in the claims should be construed to embrace these dispersing mediums and solvent or'solvent mixture. base and their solvent properties are known, no difliculty is presented in selecting a. suitable solvent or solvent mixture for use in the subbin compositions.

The following specific examples illustrate several of the various methods of applying these amides as'anti-static agents in gelatin subbing compositions, and it will be understood that these examples merely represent the preferred embodi ments and are not to be considered as limitatlve.

Example I A film base of cellulose acetate was coated with the following gelatinous substrating composilight-sensitive emulsion layer was coated directly thereon. During the coating of the light-sensitive emulsion upon the subbed base no static electricity was generated. After exposure and processing the emulsion adhered tenaciously to Since the materials suitable for film Example IV Parts Gelatin 1.5 Water 15.0 Salicylic acid, 0.5 Diamyl phen l 3.5 Formamide 1.5 -Methanoi 78.0

the cellulose acetate film support, and the deveiopcd film showed no black streaks or lines.

Example I! A film base of cellulose acetate-propionate havprocessing the emulsion adhered tenaciously to the cellulose acetate film support, and, the developed film showed no black streaks or lines;

The foregoing composition was found to be excellent as a sub for a synthetic linear polymer film base of the type described in United States Patents 2,071,250-2-3 and 2,130,948.

The-subbed photographic film bases produced according to the present invention, in addition to preventing the accumulation of static electricity when unwound during a coating operation, were found to be very satisfactory from the standpoint of physical requirements, such as, high strength, flexibility, and good water-resistance.

The small quantity of the amide, which may remain with the gelatin after evaporation of the water and organic solvent from the subbing composition, has no adverse efiect upon the lightsensitive emulsion layer, nor has the subbing composition any adverse effect upon the con tainers in which it is stored, or upon the coating equipment employed.

It will be understood that wherein the claims appended hereto the term "subbing is used, that such is intended to include the operation of applying a subbing layer from any one or the subbing compositions prepared in accordance with a the present invention.

While the present invention has been described in considerable detail with respect to certain preferred materials, it is understood that the class of gelatin dispersing agents, solvents, or mixture of such solvents is not limited thereto and that numerous variationsand modifications described in the foregoing specification may be made. As for example, a mixture of two or more of the amides may be employed as anti-static agents.

- Similarly, a film support maybe coated on both sides with the subbing compositions prepared in accordance with the present invention for the wherein R'is, a member selected from the class consisting of hydrogen and an alkyl group of not more than 3 carbon atoms, R1 is a member selected from the class consisting of hydrogen, an alkyl group of not more than 2 carbon atoms, and an alkylol group of not more than 2 carbon atoms,

and R2 is a member selected from the class consisting of hydrogen and an alkyl group of the same value as R1.

2. An anti-static gelatin composition suitable for the subbing of a photographic film support, which comprises a gelatin subbing composition containing from 0.5 to 1.5% of gelatin, from 1.33 to 15% of water, from 78 to 95.4% of a solvent for said support, and 0.5 to 10% of formamide.

3. An anti-static gelatin composition suitable for the subbing of a photographic film support, which comprises a gelatin subbing composition containing from 0.5 to 1.5% of gelatin, from 1.33 to 15% of water, from 78 to 95.4%.01 a solvent for said support, and 0.5 to 10% of acetamide.'

4. An anti-static gelatin composition suitable bing oi a photographic film support which consists of the following constituents:

Parts by weight Gelatin 0.73 Water 1.33 Acetic aci 1.20 Formamide 1.34 Methanol 75.53 Acetone 19.87

6. A gelatin composition suitable for the subbing of a photographic film support which consists of the followingconstituents:

. Parts by weight Gelatin -4 1.0 Water 2.5 Acetic acid 1.5 Acetamide I 1.0 I Methanol 74.0 Methyl acetate 20.0

7 l 7. A gelatin composition suitable for the subbing of a photographic film support which consists of the following constituents:

FRANK mxaszimA.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,101,574 Dangelmajer Dec. 7, 1937 2,225,604 Lubs Dec. 17, 1940 2,240,470 Swan Apr. 29, 1941 2,313,570 Nadeau Mar. 9, 1943 2,341,877

Middleton et a1 Feb. 14, 1944