04/843907

03/07/1972

07/03/1969

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Polaroid Corporation (Cambridge, MA)

430/10

283/77, 283/109, 430/202, 283/112, 430/256, 283/904

G03C11/08; G03C11/00; G03C5/54

96/27,29 40/2.2

Torchin, Norman G.

Goodrow, John L.

This application is a continuation-in-part of application Ser. No. 451,705 now abandoned, filed Apr. 29, 1965.

What is claimed is

1. A laminar structure comprising a transparent layer at least one surface of which comprises a transparent hydroxylated polymer selected from the group consisting of polyvinyl alcohols, hydrolyzed polyvinyl acetates and hydrolyzed cellulose esters; and, bonded directly to said hydroxylated polymeric surface, the surface of a color photographic image formed on a dyeable stratum comprising a mixture of polyvinyl pyridine and polyvinyl alcohol by the process comprising the steps of developing a latent image contained in an exposed silver halide emulsion layer with an aqueous alkaline processing solution in the presence of at least one dye developer thereby to provide in said emulsion layer a predetermined distribution of unoxidized dye developer and transferring at least part of said distribution of unoxidized dye developer, by imbibition, from said emulsion layer to said stratum to impart to said stratum a positive dye transfer image.

2. A laminar structure as defined in claim 1 wherein said polyvinyl pyridine is poly-4-vinyl pyridine.

3. A laminar structure as defined in claim 2 wherein said transparent hydroxylated polymer is polyvinyl alcohol.

4. A laminar structure as defined in claim 2 wherein said transparent layer is surface-hydrolyzed cellulose acetate.

5. A laminar structure as defined in claim 2 wherein said transparent layer comprises a cellulose acetate butyrate support, subcoated with a first layer comprising cellulose nitrate, a second layer comprising cellulose nitrate and hydrolyzed polyvinyl acetate, and a third layer consisting essentially of polyvinyl alcohol.

6. A laminar structure as defined in claim 5 wherein the nonsubcoated surface of said cellulose acetate butyrate support contains a layer of polymerized polyethylene glycol dimethacrylate.

7. A tamperproof identification card comprising a laminar structure as defined in claim 1.

8. The process for preparing a laminar structure which comprises developing a latent image contained in an exposed silver halide emulsion layer with an aqueous alkaline processing solution in the presence of at least one dye developer to thereby provide in said emulsion layer a predetermined distribution of unoxidized dye developer; transferring at least part of said distribution of unoxidized dye developer by imbibition from said emulsion layer to an image-receiving layer comprising a mixture of poly-4-vinyl pyridine and polyvinyl alcohol in superposed relationship with said emulsion layer to impart to said image-receiving layer a reversed, positive dye image of the developed image; stripping said image-receiving layer from said emulsion layer, providing thereby a diffusion transfer color photographic print; and pressing the image-bearing surface of said diffusion transfer color print, while still wet from photographic processing, onto a hydroxylated polymeric surface of a transparent sheetlike element at least one surface of which comprises a hydroxylated polymer selected from the group consisting of polyvinyl alcohols, hydrolyzed polyvinyl acetates, and hydrolyzed cellulose esters to bond said print to said element.

9. The process for preparing a laminar structure which comprises developing a latent image contained in an exposed silver halide emulsion layer with an aqueous alkaline processing solution in the presence of at least one dye developer to thereby provide in said emulsion layer a predetermined distribution of unoxidized dye developer; transferring at least part of said distribution of unoxidized dye developer by imbibition from said emulsion layer to an image-receiving layer comprising a mixture of poly-4-vinyl pyridine and polyvinyl alcohol in superposed relationship with said emulsion layer to impart to said image-receiving layer a reversed, positive dye image of the developed image; stripping said image-receiving layer from said emulsion layer, providing thereby a diffusion transfer color photographic print; allowing the image-bearing surface of said diffusion transfer color photographic print to dry; wetting said image-bearing surface with water; and pressing the thus wet surface onto the hydroxylated polymeric surface of a transparent sheetlike element at least one surface of which comprises a hydroxylated polymer selected from the group consisting of polyvinyl alcohols, hydrolyzed polyvinyl acetate, and hydrolyzed cellulose esters to bond said image-receiving layer containing said dye image to said polymeric surface.

10. A tamperproof laminar structure comprising a first wall, which first wall comprises a transparent first layer at least the inner surface of which comprises a hydroxylated polymer selected from the group consisting of polyvinyl alcohols, hydrolyzed polyvinyl acetate, and hydrolyzed cellulose esters, and a second layer comprising a color photographic print, the image-bearing surface of which is bonded to said first layer in a security seal; and a second wall, which wall comprises a backing for said first wall, and which backing is sealed about at least a portion of its periphery to said first wall, said color photographic print being formed by the process comprising the steps of developing a latent image contained in an exposed silver halide emulsion layer with an aqueous alkaline processing solution in the presence of at least one dye developer thereby to provide in said emulsion layer a predetermined distribution of unoxidized dye developer and transferring at least part of said distribution of unoxidized dye developer by imbibition from said emulsion layer to a stratum comprising a mixture of poly-4-vinyl pyridine and polyvinyl alcohol in superposed relationship with said emulsion layer to impart to said stratum a positive dye transfer image.

11. The process as defined in claim 10 wherein said hydroxylated polymer comprises polyvinyl alcohol.

This invention relates to a novel and improved card that serves to identify its holder.

A further object of the present invention is to provide an identification card, or the like, which bears a photographic likeness of the holder in color and which will automatically be defaced by, or will automatically reveal any attempt to change or alter said photographic likeness.

A further object of the present invention is to provide an identification card of the type described above which is durable and which will provide a long and useful service life.

A further object of the present invention is to provide novel laminations comprising photographic likenesses in color which cannot be separated without destroying or defacing said photographic likenesses.

Other objects of the invention will in part be obvious and will in part appear hereinafter.

The invention accordingly comprises the process involving the several steps and the relation and order of one or more of such steps with respect to each of the others, and the product possessing the features, properties, and the relation of elements which are exemplified in the following detailed disclosure, 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 accompanying drawing wherein:

FIG. 1 is a cross section, greatly magnified, of a lamination made in accordance with this invention;

FIG. 2 represents a plan view of one stage in the preparation of one embodiment of the laminations of this invention;

FIG. 3 represents a section taken along lines 3--3 of FIG. 2; and

FIG. 4 represents a section of the embodiment shown in FIGS. 2 and 3 when complete.

Numerous cards have been proposed which are designed to identify their holders to others. Typical examples are the so-called "credit cards" provided by various commercial enterprises, such as department stores, service stations, and the like, automobile drivers' licenses, or identification badges, such as those used to identify the personnel of plants or buildings where employees are limited in their right of access to predetermined portions of the plant or building. In such instances, it is of great importance to provide persons with an identification card or badge which is difficult or impossible to counterfeit and which immediately identifies its wearer, preferably by containing a photographic likeness of him. In particular, it is highly desirable to provide a card or badge which comprises a photographic likeness of its holder in color together with any other desired identifying indicia, which card or badge is laminated to a transparent rigid or semirigid film by way of a so-called "security seal," that is, a seal which cannot be broken or tampered with without immediately clearly rendering obvious the intrusion by destroying or defacing the photographic likeness.

Where the identification card contains a photographic likeness of its holder, it is desirable, in the interest of speed and efficiency, to provide a rapid means of obtaining such a likeness. Of particular advantage in this respect are photographic images of the type which may be produced by color diffusion transfer processes. In such processes a sheet of photosensitive material is exposed to create therein a latent image. The latent image is developed and, concurrent with and under the control of this development, an imagewise distribution of color-providing material is formed. At least a portion of these color-providing materials is transferred by means of an alkaline aqueous processing solution to a superposed image-receiving layer to form a color positive image thereon. As examples of such processes, mention may be made of the processes claimed and disclosed in U.S. Pat. No. 2,983,606, issued May 9, 1961 to Howard G. Rogers, wherein dye developers (i.e., a dye containing a silver halide developing function and capable of developing exposed silver halide) are the color-providing materials; the processes claimed and disclosed in U.S. Pat. No. 2,647,049, issued July 28, 1953, to Edwin H. Land, wherein color developers are employed to develop the latent image and color couplers are the color providing materials; and the processes disclosed in U.S. Pat. No. 2,774,668, issued Dec. 18, 1956, to Howard G. Rogers, wherein complete, preformed dyes which are capable of coupling are used as the color providing substances.

In color diffusion transfer processes employing dye developers, a latent image in a photosensitive silver halide element is developed in the presence of a dye developer and, as a result of this development, the dye developer in the exposed areas is oxidized and substantially immobilized. At least a portion of the immobilization is believed to be due, at least in part, to a change in the solubility characteristics of the dye developer upon oxidation and especially as regards its solubility in alkaline solutions. In unexposed and partially exposed areas of the emulsion, the dye developer is unreacted and diffusible, and thus provides an imagewise distribution of unoxidized dye developer, dissolved in the liquid processing composition, as a function of the point-to-point degree of exposure of the silver halide emulsion. At least part of this imagewise distribution of unoxidized dye developer is transferred, by imbibition, to a superposed image-receiving layer or element, said transfer excluding oxidized dye developer. The image-receiving element receives a depthwise diffusion, from the developed emulsion, of unoxidized dye developer without appreciably disturbing the imagewise distribution thereof to provide a reversed or positive color image of the developed image.

The image-receiving element used in processes of the aforementioned type generally comprises an opaque or transparent support coated with an image-receiving layer of a dyeable material which is permeable to the alkaline aqueous processing solution. The dyeable material generally comprises polyvinyl alcohol together with a polyvinyl pyridine polymer such as poly-4-vinyl pyridine polymer. As examples of the image-receiving elements just described mention may be made of those materials described in U.S. Pat. No. 3,148,061, issued Sept. 8, 1964 to Howard C. Haas, and in the aforementioned U.S. Pat. No. 2,983,606.

Diffusion transfer photographic processes of the type described above are particularly adapted for use in a Polaroid Land Camera made by Polaroid Corporation, Cambridge, Massachusetts 02139, or a similar camera structure such, for example, as the camera forming the subject matter of U.S. Pat. No. 2,435,717, issued to Edwin H. Land on Feb. 10, 1948.

Where photographic likenesses of individuals are desired for identification card purposes, the foregoing process when used in camera of the aforementioned type renders it possible to obtain such likenesses immediately upon making the photographic exposure, and obviates the necessity of the usual waiting period required for conventional photographic processes wherein a negative must be photoexposed and developed in a separate subsequent operation. However, owing to the nature of the image-receiving element as described above, it has been found that where it has sought to laminate the final positive color image to any conventional transparent supporting material, the image layer tends to separate, or be easily separable from, the transparent overlay. This was found to be particularly true when laminations were sought to be made between the positive color image and various transparent supports using heat or pressure sensitive adhesives.

It has now been found that excellent security seals can be provided for diffusion transfer color photographic images of the aforementioned type formed on a dyeable stratum comprising polyvinyl alcohol and polyvinyl pyridine by laminating such images to transparent layers which comprise a hydroxylated polymer, preferably a polyvinyl alcohol, modified polyvinyl alcohol, or cellulose, which layer may have any desirable transparent support. In order to provide the security seal, it is necessary only to wet the surface of the diffusion transfer image with water and press it firmly onto the transparent hydroxylated polymeric overlay. Alternatively, if the image-receiving element has been freshly stripped from the photosensitive element and is still "wet," it may be pressed directly onto the surface of the hydroxylated polymer layer without additional wetting. If the latter method is employed, i.e., no additional wetting of the image-receiving element prior to lamination, the lamination procedure should take place as soon as possible after the image-receiving element is stripped from the photosensitive element, preferably within 10 seconds thereof. If a longer time is permitted to elapse, while the image-receiving element may still be damp, the moisture remaining on its surface may be insufficient to provide a good security seal.

As examples of materials which may be used to provide the hydroxylated polymeric layers for the laminations of this invention mention may be made of polyvinyl alcohol; oriented, light-polarizing polyvinyl alcohol-polyvinylene; oriented polyvinyl alcohol containing dichroic dyes; vinyl alcohol containing copolymers such as polyvinyl acetate; and cellulose. The selection of the particular hydroxylated polymer to be employed will depend in part upon the desired rigidity of the overall lamination, and in part upon the nature of the transparent support for the layer, where one is employed.

Where it is desired that the outer surface of the lamination have certain properties which are not characteristic of the above hydroxylated polymers by themselves, such as a high degree of rigidity or hardness, a suitable transparent support may be used over the hydroxylated polymer layer. Preferably, such a support is bonded to the hydroxylated polymer layer prior to its lamination to a diffusion transfer image, but it may also be bonded after such lamination procedures in accordance with bonding techniques known to the art. As examples of supports for hydroxylated polymeric layers which are useful in the preparation of security-sealed diffusion transfer print lamination, mention may be made of cellulose esters such as acetate, cellulose acetate butyrate, polyvinyl acetate, and other transparent polymeric films. It will be appreciated that where such supports are bonded to hydroxylated polymeric layers as described above, depending upon the nature of the particular hydroxylated polymer and the support, bridge bonds may be necessary to insure a secure structure. The selection of the appropriate bridge bonding layer is within the realm of the skilled chemist in such instances.

In certain instances where a support is desired, the support may be combined with the hydroxylated polymer in a single layer by providing a film of a material such as polyvinyl acetate or a cellulose ester, and hydrolyzing the surface of the film so that the surface consists essentially of polyvinyl alcohol, or cellulose, respectively.

As was stated previously, security sealed laminations comprising diffusion transfer color photographic prints may be prepared by placing the wet surface of the print against a hydroxylated polymeric surface of the type described above and pressing the surfaces together. High pressures are not necessary to achieve the security bond, but may aid in the exclusion or expulsion of any air which may be trapped between the layers, and may reduce the time necessary for the bond to "set." If the color print is dry immediately prior to lamination, water alone may be used to wet the surface in order to form a security seal. If the print is thoroughly dry, however, while water alone provides a seal, in the preferred embodiment the water used to wet the surface includes dissolved polyvinyl alcohol which provides a doping material. Solutions containing up to 10 percent polyvinyl alcohol, preferably completely hydrolyzed, have been found to be particularly efficacious in this respect. Higher concentrations of polyvinyl alcohol may be employed but such solutions give no added advantage in the preparation of the lamination and may prove undesirably viscous for mechanical considerations. Moreover, the higher the polyvinyl alcohol concentration in the wetting solution, the longer it takes for the seal to "set" and dry.

In preparing laminations of the type described above, the wet diffusion transfer photographic image may be simply placed in face-to-face relationship with the hydroxylated polymer overlay and pressure applied directly. Alternatively, the print to be laminated may be fed, together with the transparent overlay material, between two rolls ordinarily known as "V-ing rolls." If the surface of the print had not been wet previously, it can be readily wetted during the latter lamination procedure by spreading a droplet of water along one edge of the surface of the print immediately prior to its being fed into the V-ing rolls. The droplet of water then forms at the nip between the surfaces being laminated and passes over the surfaces, thus effectively wetting the print layer.

An additional suitable method for simultaneously wetting the surface of the diffusion transfer color print and then laminating it to the transparent overlay is described in U.S. Pat. No. 2,798,021, issued July 2, 1956 to Edwin H. Land. In this procedure, the wetting solution is contained in a sealed, rupturable container which when ruptured by a suitable pressure applying means such as pressure-applying rollers, discharges its contents; means are provided for spreading the contents between the surfaces being laminated.

Where the transparent hydroxylated polymeric overlay comprises a light polarizing material, a second security feature is added to the final laminated photographic image, in addition to that provided by the security bond. Any attempt to tamper with or otherwise alter the surface of the laminate, e.g., by cutting into the material and subsequently fusing the cut edges by means of a solvent or heat, affects the light polarizing properties of the surface to the extent that the intrusion can be readily detected with a suitable light polarizing analyzer. The use of transparent light polarizing sheets as a security feature for laminates is described and claimed in U.S. Pat. No. 3,313,052, issued Apr. 11, 1967.

Referring now to the drawing, FIG. 1 represents a cross section greatly magnified of a laminar structure made in accordance with this invention. As shown, the laminate comprises a stratum 6 of polyvinyl alcohol-polyvinyl pyridine containing a diffusion transfer color photographic print, the image-bearing surface of which is bonded to a transparent hydroxylated polymeric overlay 5 via security seal 7. It is noted that while the surface of the transparent overlay which is bonded to the print must comprise a hydroxylated polymer as described above, the entire sheet need not necessarily comprise the same material but may include any desirable transparent backing as well.

FIGS. 2 through 4 represent a special embodiment of this invention, which may be characterized as an envelope or pouch comprising a diffusion transfer color photographic print laminated to one of its surfaces in a security bond.

FIG. 2 is a plan view of an envelope or pouch prior to lamination. The envelope or pouch comprises wall 9, at least the inner surface of which comprises a hydroxylated polymeric material, which wall is heat-, solvent-, or adhesive-sealed around a portion of its periphery 10 to a nonadhesive backing 8, which is preferably flexible, leaving the remainder of the periphery open for insertion of the diffusion transfer print.

FIG. 3 is a section taken along lines 3--3 of FIG. 2, and shows the relationship of wall 9, with its inner hydroxylated polymeric surface, sealed at its periphery 10 to nonadhesive backing 8.

Envelope or pouches of the foregoing nature provide ready structures for lamination to diffusion transfer color prints. The color print to be laminated, either still fresh and wet from its prior photographic processing or mechanically wetted, is inserted into the pouch or envelope by way of its open end, in such a way that the wet image-bearing surface is immediately adjacent to the hydroxylated polymeric inner surface of the front wall. Thereafter, the entire envelope is subjected to pressure, such as by passing it between "V-ing rolls" to provide the security bond. (The use of V-ing rolls to provide the necessary pressure gives the additional advantage that any excess moisture on the print surface can be forced out of the envelope by way of its open end.) Preferably, the envelope is then heat-sealed along its remaining open side.

FIG. 4 is a section similar to that of FIG. 3, showing the relationship of the elements when a completed laminate is prepared as just described. The final structure is an envelope or pouch comprising a transparent front wall 9 at least the inner surface of which comprises a hydroxylated polymeric material of the nature previously described, to which is bonded the image-bearing surface of a diffusion transfer color photographic print 6 in a security bond 7. Front wall 9 is heat-, solvent-, or adhesive-sealed at its periphery 10, and at its periphery 11 to nonadhesive backing 8, to provide a sealed, tamperproof lamination.

As was stated above, in envelope or pouches of the foregoing nature, transparent front wall 9 may be sealed at its periphery to backing 8 by means of heat, a solvent, or adhesive, depending upon the nature of the materials which comprise the walls. It is known that certain hydroxylated polymeric surfaces, such as those comprising polyvinyl alcohol, are not particularly amenable to heat sealing; however, if for reasons of convenience it is desired to use heat alone to seal the pouch, it will be apparent that outer wall 9 can comprise two layers, the outer layer consisting of a transparent material which can be heat-sealed to the particular backing employed, such as the transparent support materials disclosed previously, and the inner layer is bonded to the outer layer but ends just short of the area intended to be heat-sealed.

The following nonlimiting examples further illustrate the present invention:

EXAMPLE I

A diffusion transfer color photographic image was made in accordance with the procedures described in the aforementioned U.S. Pat. No. 2,983,606, using a Polaroid Automatic Model 100 camera. The image-receptive layer, which comprises a mixture of polyvinyl alcohol and poly-4-vinyl pyridine, together with its superposed photosensitive element was pulled from the camera; the elements were maintained in superposed position for 60 seconds, after which they were stripped apart. Immediately after stripping, while the image-receptive surface was still fresh and wet, it was pressed firmly against the surface of a linear dichroic polyvinylene-polyvinyl alcohol light polarizing sheet having a cellulose acetate butyrate backing, commercially available from Polaroid Corporation, Cambridge, Mass. 02139, and designated as type KN 42. After a period of about 2 minutes an attempt was made to separate the print from its overlay; it was found that the image adhered firmly to the overlay and could not be pulled away, even with the aid of a razor blade.

EXAMPLE II

A lamination was prepared as in Example I, except that following stripping from its photosensitive element, the surface of the image-carrying layer was allowed to dry completely, and was subsequently wet with water. The resulting lamination exhibited a security bond substantially identical to that of the lamination prepared in Example I.

EXAMPLE III

A lamination was prepared as in Example II, except that the solution employed to rewet the surface of the image-carrying layer was a 10 percent by weight solution of completely hydrolyzed polyvinyl alcohol in water. The resulting lamination exhibited a security bond substantially identical to those of the laminations in the foregoing examples; it was observed that there was less tendency for air bubbles to appear in the lamination.

EXAMPLE IV

The polyvinyl alcohol surface of a sheet comprising a cellulose acetate butyrate support, subcoated with cellulose nitrate, followed by a layer of cellulose nitrate and hydrolyzed polyvinyl acetate, and lastly a layer of polyvinyl alcohol, was laminated to a diffusion transfer color print (prepared in the foregoing manner) by the procedure described in Example III. A substantially identical security bond was formed.

Cellulose acetate butyrate films having subcoated as described above may be prepared in accordance with the teachings contained in U.S. Pat. No. 2,362,580, issued Nov. 14, 1944, to Gale F. Nadeau and Clemens B. Starck; U.S. Pat. No. 2,541,478, issued Feb. 13, 1951, to the same inventors; and U.S. Pat. No. 2,835,609, issued May 20, 1958, to Clemens B. Starck, Gale F. Nadeau and Carl F. Smith.

EXAMPLE V

The hydrolyzed surface of a sheet of cellulose tri-acetate was laminated to a diffusion transfer color print obtained or described above by the procedure described in Example III. A substantially identical security bond was formed.

Surface-hydrolyzed cellulose tri-acetate films may be prepared in accordance with the teachings contained in U.S. Pat. No. 3,078,178, issued Feb. 19, 1963, to Bertil E. Ostberg.

EXAMPLE VI

A mar-resistant layer of polymerized polyethylene glycol dimethacrylate was applied to the cellulose acetate butyrate surface of a sheet substantially identical to that used in Example IV. The polyvinyl alcohol surface of the sheet was then laminated to a diffusion transfer color print by the procedure described in Example III. A substantially identical security bond was formed, and the resulting lamination had the further advantage of having a smooth, mar-resistant outer surface.

Processes and materials for providing mar-resistant finishes on cellulose acetate butyrate surfaces may be found in U.S. Pat. No. 3,097,106, issued July 9, 1963 to Elkan R. Blout, Harold O. Buzzell and Leonard C. Farney.

After initial attempts to separate the laminations of each of the foregoing examples proved unsuccessful, the laminations were subjected to the following test conditions:

1. stored at 140° C. for 16 hours.

2. packed in Dry Ice for 2 hours.

3. suspended for 10 days over a hot saturated sodium chloride solution.

4. refrigerated overnight.

5. stored at 100° F. at 80 percent relative humidity for 10 days.

6. subjected to dry air at 90° C. for about 1 hour.

None of the foregoing tests were found to have any affect on the security bond. In test (2) in which the laminates were packed in Dry Ice, the laminates readily shattered; the image could still not be separated from the rest of the laminate, even in a fragmented condition.

As was heretofore mentioned, the image-receiving elements employed in the practice of this invention include a dyeable stratum comprising a mixture of polyvinyl alcohol and a polyvinyl pyridine polymer such as a poly-4-vinyl pyridine polymer. The ratio of polyvinyl alcohol to polyvinyl pyridine may be on the order of from about 8:1 to about 1:2 by weight, a preferred ratio for preparing color transfer images being from about 1:1 to about 3:1. This stratum typically also contains a dye mordant and other materials useful in the diffusion transfer processes may also be incorporated in this stratum.

In view of the fact that polyvinyl alcohol to polyvinyl alcohol bonds are known to be weak, the strength of the security seal in laminations prepared in accordance with this invention is totally unexpected. In other words, since the stratum containing the color image to be protected by lamination is in part made of polyvinyl alcohol, one would not expect the strength of the seal even to be satisfactory, much less of the high order as evidenced by the foregoing illustrative examples and tests.

The theoretical reasons for the strength of the seals obtained by this invention are not clearly understood. Nevertheless, the fact remains that the seal is vastly superior to that obtainable from a PVA to PVA bond and hence totally unexpected.

It will be appreciated that the term "image" as used in the foregoing discussion is intended to include not only photographic likenesses of given individuals, but also, especially when applied to identification cards and the like, includes photographically recorded indicia which may form a part of the final picture.

In the preceding portions of the specification, the expression "color" has been frequently used. This expression is intended to include the use of a plurality of colors to obtain black.

Since certain changes may be made in the above process and product without departing from the scope of the invention 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.