US 3206311 A
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Description (OCR text may contain errors)
Sept. 14, 1965 J. E. CAMPBELL ETAL 3,206,311
STACKED PHOTOSENSITIVE ELEMENTS Filed May 5. 1961 PHOTOSENSITIVE LAYER 8.9. SILVER HALIDE l0 SUPPORT A l4 &\\\\\\\ 5 com-me COMPRISING PRIMARY AMIDES DERIVED FROM HIGHER FATTY ACIDS kvwww ORNEYS United States Patent 3,206,311 STACKED PHOTOSENQTIVE ELEMENTS John E. Campbell, Needham, and John J. Dennis, In,
North Quincy, Mass., assignors to Polaroid Corporation, Cambridge, Mass, a corporation of Delaware Filed May 5, 1961, Ser. No. 108,051
- 7 Claims. (Cl. %-87) This invention relates to photographic elements or material and more particularly to elements having low w efficients of static friction.
A principal object of the present invention is to provide photographic elements such as, for example, photosensitive elements having a slip layer or coating which possesses a very low friction coeflicient.
Another object of the invention is to provide photographic elements having a slip coating of the above type which does not adversely affect photosensitive coatings or layers when in direct and tight con-tact therewith.
Still another object of the invention is to provide photographic elements having a slip coating comprising an organic polymeric material and one or more primary, str-aightch-ained amides having at least 8 carbon atoms.
A still further object of the invention is to provide photographic elements having a slip coating comprising an organic polymeric material and a mixture of primary, straight-chained amides having 18 carbon atoms.
Still another object of the invention is to provide a method of lubricating all types of photographic material or elements.
Other objects of the invention will in part be obvious and will in part appear hereinafter.
The invention accordingly comprises the several steps and the relation and order of one or more of such steps with respect to each of the others, and the products possessing the features, properties and the relation of elements which are exemplified in the following detailed dis-closure and the scope of the application of which will be indicated in the claims.
For a fuller understanding of the nature and objects of the invention, reference should be had to the following detailed description taken in connection with the drawing wherein a photographic product is disclosed, in exaggerated cross section, illustrating the back or slip coating of the present invention.
It is well known that problems of static, friction, and the like are frequently encountered during the manufacture or during the use .of certain photographic materials such as, for example, photosensitive elements. In order to substantially reduce or eliminate these problems so as to facilitate handling and other operations as applied to such photographic materials or products, it has generally been the practice to employ, for example, anti-static coatings, slip or lubricating coatings or some other expedient such as interleaving or the like.
P-hotosens-itive elements present particular problems. For example, in many instances, a photosensitive element in strip form is tightly wound for insertion into cassettes, magazines or the like, or a plurality of photosensitive elements of a predetermined size are tightly stacked in parallel relationship in a magazine or housing such as shown, for example, in US. Patents Nos. 2,435,- 720, 2,495,111, 2,930,299, 2,946,270, 2,978,971 and many others. In such instances, a photosensitive layer is in direct and intimate contact with the backing of a photosensitive element. Thus, in addition to reducing static and friction, any backing coat or layer carried by a photosensitive element to be used as above must not otherwise adversely affect the photosensitive layer with which it is in contact. In the present invention there are provided photographic products such as photosensitive elements having on one surface thereof, e.g., the back, a thin con- "ice tinuous layer or coating comprising an organic polymeric material and at least one primary, straight-chained amide derived from a fatty acid having at least 8 carbon atoms. In one embodiment of the invention, said coating comprises a cellulose plastic such as a cellulose ester or cellulose ether and a mixture of amides containing 18 carbon atoms and, more particularly, a mixture of octadecanamide, 9-octadecenamide and 9,IZ-Octadecadienamide. It has been found that such coatings not only substantially reduce static and friction, but also do not transfer off to produce undesirable effects or cause fogging or desensitization of photosensitive layers or emulsions.
Referring now to the drawings there is illustrated a photosensitive element comprising .a base or support-10, a photosensitive layer 12 carried by one surface or side of support 10, and .a backing or slip coating 14 carried by the other side of support 10. The support 10 may be comprised of any of the flexible sheet materials generally used for film base, including paper, organic plastics such as cellulose esters, e.g., cellulose acetate etc., and the like. In some instances there may be employed a supp-ortfltl which is opaque to light actinic to the photosensitive layer 12 or which includes a layer, for example, slip coating 14, which is opaque to actinic light.
The photosensitive layer 12 may comprise any of the materials usually employed in photography including, for example, the silver halides or other photosensitive heavy metal salts capable of having a developa-ble latent image formed therein by exposure to actinic light, the ferric salts and the di-azonium compounds. In one form, photosensitive layer or stratum 12 contains one or more of the silver halides, of which silver chloride, silver bromide and silver iodide are examples, dispersed on a suitable protective colloid material, for example, gelatin, agar, albumin, casein, a cellulose such as carboxymethyl cellulose, a vinyl polymer such as polyvinyl alcohol or a linear polya-mide such as polyhexamethylene adipamide. Examples of specific formulations of conventional emulsions suitable for use are described in T. T. Baker, Photographic Emulsion Technique, American Photographic Publishing Company, Boston, 1948, Chapter IV.
It should be pointed out that although only the use of one photosensitive layer is illustrated, such as may be utilized for the production of a black-and-white or'mon-ochromatic image, it is to be understood that more than one can be employed, such as may be the case where a multichromatic image is desired. For obtaining color images thereby may be contained in separate layers or in one or more silver halide layers, for example, various other components such as sensitizers, couplers, dyes and the like. A detailed description of the various possible arrangements of photosensitive layers or other layers associated therewith or of the compositions thereof for the production of black-.and-white or color images need not be given here since such are so well-known to the art.
The slip or back coating 14 comprises an organic polymeric material and at least one primary, straight-chained amide derived from a higher fatty acid. The amides of the present invention and .a suitable organic film-forming polymeric material such as, for example, a cell-ulosic plastic, are preferably applied from certain solvents or media in controlled amounts to support 10 so as to form thereon a thin backing layer or coating.
The amides which may be utilized in back coating 14 may be generically depicted by the following formula:
where R represents a straight-chained aliphatic group containing from about 7 to 17 carbon atoms. Among the amides which may be employed in coating 14-, mention may be made of decanamide, dodecan-amide, tetradecancoating 14 may contain only .a single amide such as 9- octadecenamide or it may contain a mixture of amides such "as ioctadecanamide, 9-0ctadecenamide and 9,12- octadeoadiena'mide. One preferred amide mixture of the invention comprises, by weight, about 6 percent oc-tadecanamide, about 91 percent oct-adecenamide and about 3 percent octadecadienamide. Other mixtures such as those of the following approximate compositions may alsojbe utilized: (1) 3% hexadecanamide, 93% octa-decanamide and 4% 9-oct-adecenamide; (2) 22% hexadecanalmide, 75% octadecan-amide and 3% 9-octaclecenamide; and (3) 8% octanam-ide, 7% decanarnide, 49% dodecanamide, 17% tetradecanamide, 9% hexadecana'mide, 6% 9-octadecena'mide and 2% each of octadecana-mide and 9,12- octadecadienamide.
Coating 14 in addition to the preferred amide also contains an organic film-forming polymeric or resinous material. Among the suitable polymeric materials men- "tion may be made on the cellulosic plastics such as the cellulose ethers and esters, e.g., cellulose acetate butyrate,
ethyl cellulose, cellulose nitrate and the like. The polymeric'material serves as a binder for the amide or amides employed sov as to prevent or substantially reduce the transfer of amide from the coating. Moreover, in instances where the support is of paper, the polymeric material prevents undesirable penetration of amide into the paper. The quantity of polymeric material employed depends upon many factors such as, for example, the
type of coating machine, the nature of the amide or amides utilized, the coating thickness desired and the like. Thus, the quantity of polymeric material may be varied considerably.
Coating 14 may be formed by applying to support a suitable solution or dispersion, e.g., an emulsion containing the desired polymeric material and amide or amides. The amides of the present invention are soluble in acetones, esters, alcohols, and other materials and thus .may be easily applied in-solution. Preferably the solvent or combination of solvents employed for dissolving the amide or amide mixture is also preferably a mutual solvent for the film-forming polymeric material utilized.
For a further understanding of the invention, reference "should be had to the following non-limiting examples:
Example I solvent removed. Wherein the frictional value of the untreated paper was 0.36,. paper treated or coated with the above composition reduced this static value to 0.11- 0.15. Thus the coefficient of friction of the photosensitive element was reduced more than 50%. Moreover,
it was found that there was no transfer of the amides from the coating to produce undesirable effects nor did the coating cause fogging or desensitization of a photosensitive layer when in intimate and prolonged contact therewith. Film pack tests wherein a plurality of treated photosensitive elements were tightly stacked in parallel relationship in a magazine resulted in the easy and smooth withdrawal of one element at a time, in proper sequence, from the magazine.
Example II Other satisfactory backing or slip coats for paper base photographic elements were obtained from the following compositions:
Ethyl cellulose "grams" 3.2 Preferred amide mixture do 1.2 Isopropyl alcohol cc 59.2 Ethyl acetate cc 36.4 Cellulose nitrate grarns 3.8 Preferred amide mixture do 1.2 Isopropyl alcohol cc 57.0 Ethyl acetate cc 36.0
Example III In addition to the above coating compositions, a dispersion or emulsion composition such as set forth below may also be employed.
To an emulsion comprising 15.0 grams of cellulose acetate butyrate, 34.0 cc. of ethyl acetate, 13.5 cc. of toluene, 2.5 cc. of Tween 20 (trademark of Atlas Powder Co. for an emulsifying agent comprising a sorbitan monolaurate polyoxyalkylene derivative) and 24.0 cc. of water, there was added a composition comprising 1.0 gram of the preferred amide mixture and 10.0 cc. of ethyl acetate. The emulsion produced from the above materials was then coated upon a paper base and dried. Wherein the paper had an initial static coefiicient of friction of 0.36, the coating produced from the above emulsion reduced this value to 0.22.
It should be noted that an opacifying agent such as a suitable dye, e.g., red or black, or pigment such as carbon black may be added to any of the above compositions so as to obtain a coating which is opaque to light. Thus, for example, coating 14 may comprise cellulose acetate butyrate, the preferred amide mixture and carbon black.
The concentration or quantity of the amide or amides in the coating composition may be varied considerably. When employing the preferred amide mixture, concentrations of between about A of 1 percent and about 2 percent have been found to be satisfactory. Concentrations of the preferred amide mixture on the order of about 1.0 to about 1.2 percent of the total coating composition such as illustrated in the examples provide excellent back coatings.
Although the invention has been described in connection with photosensitive elements, it is also applicable to other photographic structures. For example, in many film pack structures, the leader of each photosensitive element is so arranged that a substantial portion thereof is in direct and tight contact with a photosensitive layer and movable thereover. It has been found that the co- ,eificient of friction therebetween can be substantially reduced and satisfactory results obtained when the contacting surface of a leader which is generally constructed of paper is provided with the slip coatings of the present invention.
Since certain changes may be made in the above process an vention herein involved, it is intended that all matter contained in the above description or shown in the accompanying drawing shall be interpreted as illustrative and not in a limiting sense.
What is claimed is:
1. A photographic product comprising a plurality of a photosensitive element and movable thereover, said first contact surface of ea-ch said photosensitive element being in contact with another contact surface provided by at least one of (a) the second contact surface of another of said photosensitive elements and (b) a third contact surface provided by a surface of a paper leader, one of said second and third contact surfaces having coated thereon, as a slip coat, a continuous layer comprising a mixture of (a) at least one primary, straight-chained amide containing from about 8 to 18 carbon atoms and (b) a polymer selected from the group consisting of cellulose acetate butyrate, ethyl cellulose and cellulose nitrate, said polymer substantially preventing transfer of said amide from said slip coat, and said slip coat substantially reducing the coefficient of friction between said first contact surface and said other contact surface.
2. A photographic product as defined in claim 1, wherein said slip coat is coated on said second contact surface of said photosensitive element.
3. A photographic product as defined in claim 1, wherein said slip coat is coated on said surface of said paper leader providing said third contact surface.
4. A photographic product as defined in claim 1, wherein said polymer is cellulose acetate butyrate and said amide is a mixture of octadecanamide, 9-octadecenamide and 9,12-octadecadienamide.
5. A photographic product as defined in claim 4, wherein said mixture comprises about 6% of octadecan- 6 amide, about 91% of 9-octadecenamide and about 3% of 9,12-octadecadienamide.
6. A photographic product as defined in claim 5, wherein said mixture comprises between about of 1% and about 2% of the total composition utilized to produce said slip coat.
7. A photographic product as defined in claim 1, wherein said slip coat includes carbon black.
References Cited by the Examiner UNITED STATES PATENTS 1,957,912 5/34 Seel 117-157 2,070,991 2/37 Hund 106-186 2,103,640 12/37 Richter 117-157 2,235,516 3/41 Cornwell.
2,258,609 10/41 Hill 96-84 2,311,073 2/43 Nadeau et al. 9684 2,415,631 2/47 Galley 96-85 2,432,864 12/47 Dimsdale et al. 96-85 2,588,765 3/52 Robijns 96-87 2,732,305 1/56 Richman 96-84 2,751,309 6/56 Baxter 96-78 XR 2,773,769 12/56 Goldschein 96-84 2,898,805 8/59 Solow et al. 96-78 XR 3,021,229 2/ 62 Morgan.
NORMAN G. TORCHIN, Primary Examiner.
PHILIP E. MANGAN, Examiner.