US3498788A - Novel laminations for identification cards - Google Patents

Description

FIG

March 3, 1970 I H. c. HAAs 3,498,788

NOVEL LAMINATIONS FOR IDENTIFICATION CARDS' Filed July 5. 1966V FIGI V/l/l///l//l/l///////////////////////,lI a

l 5 FIG. 4 l- Marum/0MM @i ATTORNEYS UnitedStates Patent O 3,498,788 NOVEL LAMINATIONS FOR IDENTIFICATION CARDS Howard C. Haas, Arlington, Mass., assignor to Polaroid Corporation, Cambridge, Mass., a corporation of Delaware Filed July 5, 1966, Ser. No. 562,767 Int. Cl. G03c 1/48, 5/54 U.S. Cl. 96-76 1S Claims ABSTRACT OF THE DISCLOSURE This invention relates to a novel and improved card that serves to identify'its holder.

It is one object of the present invention to provide an identification card, or the like, which comprises a photographic likeness of its holder.

A further object of the present invention is to provide an identification card, or the like, which bears a photographic likeness of its holder 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 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 relation of elements Which are exemplified in the following detailed disclosure, and the scope ofthe 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:

FIGURE 1 is a cross-section, greatly magnified, of one stage in the preparation of a lamination made in accordance with this invention;

1FIGURE 2 is a cross-section, greatly magnified, of' a completed lamination made in accordance with this invention;

FIGURE 3 is an illustration of one method of preparing the laminations of this invention;

FIGURE 4 represents a plan view of one stage in the preparation of one embodiment of the laminations of this invention;

FIGURE 5 represents a section taken along line 5-5 of FIGURE 4;

FIGURE 6 represents a section of the embodiment shown in FIGURES 4 and 5 when complete; and

FIGURE 7 is a cross-section, greatly magnified, of still another lamination made in accordance with this invention.

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, and 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 diflicult or impossible to counterfeit and which immediately identifies its holder or 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 together with any other desired identifying indicia, which card or badge is laminated to a transparent rigid or semi-rigid ifilm 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 instrusion 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 silver transfer images of the type which may be produced by applying a processing composition containing a silver halide developing agent and a silver halide solvent to a photoexposed photosensitive silver halide element and an image-receptive element that are in superposed relation. The processing composition acts to reduce exposed silver halide to silver, to react with unreduced silver halide to form a Water solubie, complex silver salt, and to transfer it to the image-receptive element, and there, reduce it to silver. Examples of photographic material useful in the f production of the foregoing type of photographic silver images are described in detail in U.S. Patent No. 2,543,181 issued in the name of Edwin H. Land on Feb. 27, 1951, and in U.S. Patent No. 2,647,056 issued in the name of Edwin H. Land on July 28, 1953. In a typical process employing such materials a processing composition containing a viscous aqueous solution of a silver halide developing agent, a silver halide solvent and an alkali is spread in a uniformly thin layer between the superimposed surfaces of the photoexposed gelatino silver halide stratum of a photosensitive element and the silver-receptive stratum of an image-receptive element. The elements are maintained in superposed relation for a predetermined period ordinarily of approximately lOl to seconds in duration, during which exposed silver halide is reduced to silver and unreduced silver halide forms a water soluble, complex silver salt which diffuses through the layer of composition to the image-receptive stratum, Where, upon being reduced to silver, it forms a silver print. At the end of this period, the photosensitive element, preferably together with the solidified layer of processing composition, is stripped from the image-receptive element.

Image-receptive strata of the foregoing type include silver precipitating nuclei dispersed in a macroscopically continuous vehicle comprising sub-macroscopic agglomerates of minute particles of a water insoluble inorganic, preferably siliceous material such as silica aerogel. Silver` grains precipitated in the foregoing manner are concentrated primarily at the surface of the stratum. This straturn, both before and after receiving these precipitated silver grains, is extremely thin, preferably being approximately 1 to 8 microns thick. Materials of the foregoing type are specically described in U.S. Patents No. 2,698,- 237 and 2,698,245 issued to Edwin H. Land on Dec. 28, 1954.

The foregoing process is 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. Patent 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 cameras 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-receptive element as described above, it has been found that where it is sought to laminate the final silver transfer 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 t be made between the silver transfer image and various transparent supports using pressure-sensitive adhesives.

It has now been found that excellent security seals can be provided for silver transfer images of the aforementioned type by laminating such images to transparent layers which comprise a hydroxylated polymer, preferably a polyvinyl alcohol, modified polyvinyl alcohol, or hydrolyzed cellulose ester, which layer may have a suitable transparent backing if desired, via an intermediate layer consisting essentially of a methyl vinyl ether/maleic acid copolymer.

As examples of hydroxylated polymers which may be used as transparent layers for bonding to silver transfer images to form the laminations of this invention, mention may be made of polyvinyl alcohol; oriented, light polar-y izing polyvinyl alcohol-polyvinylene, oriented polyvinyl alcohol containing dichroic dyes, vinyl alcohol-containing copolymers such as partially hydrolyzed polyvinyl yacetate; partially hydrolyzed vinyl acetate-vinyl chloride copolymers; polyvinyl alcohol with various subcoats such as cellulose nitrate and/ or cellulose esters, and hydrolyzed cellulose esters such as hydrolyzed cellulose acetate.

The methyl vinyl ether/maleic acid copolymer is preferably coated upon the support from solution, following which the coating is permitted to dry. In the dried state the coated material is stable and may be stored for extended periods of time prior to its actual use in a lamination with a silver transfer image.

In preparing coating solutions for the laminations of this invention, the copolymer is simply dissolved in a suitable solvent, either in the form of methyl vinyl ether/ maleic acid copolymer, or alternatively, in the form of methyl vinyl ether/ maleic anhydride copolymer; where the latter form is used, the solvent should be one in which upon being dissolved, the anhydride is converted to the free acid.

It has been found Convenient to use a by weight aqueous solution of the poly(methyl vinyl ether/maleic anhydride) as the coating solution, for the reason that at such a concentration, the material is readily soluble in water; further, the solutions thus formed provide a layer of adequate thickness to give a good bond in a single coatingoperation without being unduly viscous. If desired, however, stronger or -weaker concentrations may be employed, limited only by the ultimate solubility of the material.

While in the preferred embodiment the poly(methyl vinylether/maleic acid) or poly(methylvinyl ether/ maleic anhydride) is coated from aqueous solution, it is also within the scope of this invention to employ a solution of the material in any of the organic solvents in which the copolymer is soluble in the acid form, such as lower alcohols, e.g., methanol, ethanol, etc.; aldehydes, ketones, or ketone-alcohols, e.g., benzaldehyde, acetone, diacetone alcohol', etc.; lactones or lactams, e.g., N-methyl-Z-pyrrolidone; tetrahydrofuran; and the like. There is no criticality in the thickness of the final poly(methyl vinyl ether/ maleic acid) layer, other than it be suicient to provide a secure bond to both the hydroxylated polymeric overlay and the silver transfer image. Materials which have been found to be particularly eflicacious in providing the coating solutions and layers referred to above are the series of resins commercially available from General Aniline & Film Corporation, New York 14, N.Y., under the trade name Gantrez AN, and may be designated as copolymers of methyl vinyl ether and maleic anhydride, and the partial lower-alkyl esters thereof. Poly(methyl vinyl ether/ maleic anhydride) may be represented by the formula:

When dissolved in a suitable solvent, the copolymer takes the form of the free acid:

(B) O CH3 "I GHz-CH-OH-CHM (C) I" O CH3 I CHz-CH-CH-CH.-

wherein one of R and R is a lower alkyl radical, such as methyl, ethyl, isobutyl, etc., and the remaining R or R' moiety is hydrogen. It is also within the scope of this invention to employ mixtures of the diacid copolymer of Formula B with the partial esters thereof, represented by Formula C.

It is to be noted that in general, coatings of poly(methyl vinyl ether/maleic acid) are hard and free of tackiness when dried. However, where certain of the partial lower alkyl esters of the copolymer are employed, such as the 45% partial methyl ester, the coating, even when com- 'pletely dried, is slightly tacky to the touch. This has no effect upon the security seal ultimately formed and hence, need be considered only in those instances where it is desired to prepare coated hydroxylated polymeric overlays and store such materials for a finite period prior to their use in a security seal lamination.

As as stated previously, the coatings prepared as just described consist essentially of a poly(methyl vinyl ether/ maleic acid). It will be understood that such a layer may also include minor amounts of modifying substances, such as plasticizers and the like, with which the copolymer is compatible.

When it is desired to prepare the final lamination with the silver transfer image, the dried poly(methyl vinyl ether/maleic acid) coating must be activated with water. This can be achieved either by wetting the coated surface, or by wetting the silver transfer print surface. Finally, the silver transfer print and coated surface are placed in face-to-face relationship and pressed 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. While as stated above, water alone may be used to activate the poly(methyl viny ethyl/maleic acid), in some instances it has been found helpful to include a trace of a swelling agent, such as N-methyl pyrrolidone, ethanol, propanol, or dioxane, in the activating solution. This has been found not to alter the nature of the security bond, but may tend to decrease the bond setting time.

Extremely thin photographic silver images of the foregoing types have been observed to retain traces of the photographic reagents with which they have been processed, and the continued presence of which has been found to adversely affect their stability. Thus, in theA past, it has been found desirable to physically wash such prints and coat them with a protective film-forming material. In the practice of this invention, it is still preferable that the silver transfer print be washed prior to its lamination. However, it has been found that if the lamination is achieved by feeding the print to be laminated along with the coated transparent material and a drop of activating solution between two rolls ordinarily known as V-ing rolls, a -bead of activating solution forms at the nip which effectively washes the silver transfer image. After the aqueous bead has passed over the surfaces being laminated, it is ultimately extruded, carrying with it the undesired residue of the developing composition and thus, a separate washing step is not necessary. However, where the silver transfer print and the coated transparent hydroxylated polymeric overlay are simply placed in faceto-face relationship and pressure applied directly, it is preferred that the silver transfer image first be washed with water. Where the silver transfer print is washed immediately prior to lamination, it need not be dried; the aqueous washing fluid remaining on the surface of the print in such instances may then also provide the activating solution for the poly(methyl vinyl ether/maleic acid) coating.

An alternate procedure may be used for washing and laminating silver transfer images of the aforementioned type, which procedure is particularly adapted to those instances where it is unnecessary or inexpedient to prepare the transparent hydroxylated polymer overlay in advance by coating it with the poly(methyl vinyl ether/maleic acid) and allowing the coating to dry. In this alternate procedure, an aqueous solution of the poly(methyl vinyl ether/maleic acid) is used to simultaneously coat and wash the silver transfer image, and while the coating thus applied is still fresh and wet, the print is pressed directly against the transparent hydroxylated. polymer overlay. Suitable devices and processes for simultaneously washing and coating silver transfer prints are described in U.S. Patent No. 2,768,403, issued Oct. 30, 19.56 to Charles A. Govatsos, and in U.S. Patent No. 2,963,953, issued Dec. 13, 1960 to Donald R. Bishop et al. While the bonds between the silver transfer prints and transparent overlays are equally satisfactory to those prepared by the firstdescribed procedure, the latter procedure necessitates the availability, not simply of Water, but rather, of aqueous solutions of the polymeric coating material. Where the laminating technique is desired for use as a relatively simple means for the production of tamper-proof identification cards or badges, the disadvantages of the latter procedure are obvious.

The use of poly(methyl vinyl ether/maleic anhydride) in a composition for washing and protecting silver transfer images is disclosed in the copending U.S. patent application of Edwin H. Land and Meroe M. Morse, Ser.'No. 487,578, filed Sept. 15, 1965.

An additional suitable method for simultaneously prov viding the poly(methyl vinyl ether/maleic acid) coating,

washing the silver transfer print, and laminating the print to an overlay is described in U.S. Patent 2,798,021, issued July 2, 1957 to Edwin H. Land. In this procedure, the coating material 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. It is to be noted that the procedure described in the last-mentioned patent can also be employed in the lamination of silver transfer prints to hydroxylated polymer surfaces which have previously been coated with poly(methyl vinyl ether/ maleic acid) as described above. In such a case, the rupturable container contains only activating solution (e.g., water) rather than a poly(methyl vinyl ether/ maleic acid) solution.

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 or heating it, affects the light-polarizing properties `of the surface to the extent that the attempted alteration or 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. patent application of Robert Malster, Ser. No. 451,895, filed Apr. 29, 1965 now U.S. Patent No. 3,313,- O52.

Additionally, if desired, the overlay may include a pattern, such as a stripe, comprising a mixture of dichroic dyes in an oriented polymeric substrate, such as a mixture of a positive dichroic dye of a first color and a negative dichroic dye of a second, distinct color; when viewed through a light-polarizing device, laminations of this type exhibit the original colors of the dyes comprising the mixture, as well as that of the mixture itself, thereby conferring an additional security feature upon the lamination as a whole. The use of mixtures of dichroic dyes to provide security features for information-bearing faces is disclosed and claimed in the copending application of Phoebe F. Jordan and Harold O. Buzzell, Ser. No. 513,046, filed Dec. 10, 1965, now U.S. Patent No. 3,391,- 479.

Where it is sought to provide a card or similar laminate which is suitable for embossing, it is necessary that the outermost surface of the laminate comprise a transparent, relatively rigid polymeric material of the type which is capable of permanently maintaining raised or embossed letters. Of particular efiicacy are those polymeric films known commercially as rigid vinyls, which generally comprise high chloride content vinyl acetate-vinyl chloride polymers or semi-rigid vinyls, which are similar to rigid vinyl films except that they include a small amount of a suitable plasticizer. In order to provide a hydroxylated surface on suchl vinyl films so that they can form a security bond with the poly(methyl vinyl ether/maleic acid) layers described above, it is preferred that the rigid or semi-rigid vinyl film be subcoated with a layer of a vinyl acetatevinyl chloride copolymer, having a ratio of from about 7:3 to 1:1 vinyl acetatezvinyl chloride; thereafter, the outer surface of the vinyl acetate-vinyl chloride layer is at least partially hydrolyzed so as to provide hydroxyl groups to which the poly(methyl Vinyl ether/ maleic acid) can adhere.

The use of security-sealed laminations comprising rigid and semi-rigid embosable films with other image-bearing strata is disclosed and claimed in copending U.S. application of Phoebe F. Jordan and Harold O. Buzzell, Ser. No 513,046, filed Oct. 1, 1965.

Referring now to the drawing, FIGURE 1 represents the layers as described above immediately prior to lamination, comprising a silver transfer image layer 8, a transparent hydroxylated polymer overlay 10 on which a layer 9 of poly(methyl vinyl ether/ maleic acid) has been coated and allowed to dry. A drop of aqueous activating solution 11 has been placed between silver transfer image layer 8 and layer 9 which, when spread between the layers, activates layer 9, enabling it to adhere to the silver transfer image layer 8 in a security bond.

FIGURE 2 represents the structure shown in` FIGURE l, in which the activating solution has been spread, and the respective layers pressed together to form security bond 18, thus completing the lamination.

FIGURE 3 is a cross-section greatly magnified of a laminated transfer image being prepared by one of the methods described previously. As shown, the sheet materials, comprising the silver transfer image 8, and hydroxylated polymer sheet 10 with its poly (methyl vinyl ether/ maleic acid) layer 9, are fed between two V-ing rolls 12 and 13 rotatably mounted and suitably driven in directions indicated by the arrows on the rolls. Rolls 12 and 13 are adjustable with respect to the distances between centers so that a suitable pressure may be brought to bear upon the contacting surfaces of the sheets. Numeral 11 designates an aqueous bead of activating solution maintained at the nip between the two sheets of material undergoing lamination adjacent to the point of contact. As described previously, as the aqueous bead 11 is forced by the rotation of rolls 12 and 13 over the surfaces of the layers being laminated and is extruded from between the layers at the completion of the lamination, it not only activates the poly(methyl vinyl ether/maleic acid) coating 9 but also effects a washing of the silver transfer image 8. As the completed lamination passes from rolls 12 and 13, it is characterized by the presence of security bond 18 which is formed between layers 8 and 9.

FIGURES 4 through 6 represent a special embodiment of this invention, which may be characterized as an e11- velope or pouch comprising a silver transfer image laminated to one of its inner surfaces in a security bond.

FIGURE 4 is a plan view of an envelope or pouch which has been prepared for providing the aforementioned embodiment, prior to lamination. The envelope or pouch comprises wall 15, which is made up of a transparent hydroxylated polymeric overlay, coated with a poly(methyl vinyl ether/maleic acid) on its inner surface as described previously. Wall 15 is heat, solvent, or adhesive-sealed around a portion of its periphery 16 to a non-adhesive backing 14, which is preferably flexible, leaving the remainder of the periphery open for insertion of the silver transfer print.

FIGURE is a section taken along lines 5--5 of FIG- URE 4, and shows the relationship of transparent hydroxylated polymeric layer with its dried coating 9 of poly(methyl vinyl ether/maleic acid), both of which when taken together comprise the front wall of the envelope, heat sealed at its periphery 16 to backing 14. Where poly- (methyl vinyl ether/maleic acid) is employed or where the particular poly(methyl vinyl ether/maleic ester) ernployed is one which dries free of tackiness, the envelope or pouch s0 prepared may be stored for extended periods of time prior to its use in making silver transfer print laminations; in the absence of water, layer 9 will exhibit no tendency to adhere to nonadhesive backing 14.

Envelopes or pouches so prepared provide ready structures for lamination to silver transfer prints. The print is preferably first washed with water to remove the residue of developing composition as described above, and to provide a thin lm of water to activate the poly(methyl vinyl ether/maleic acid) coating. Thereafter, the print is inserted into the pouch or envelope by way of its open end, in such a way that the image-bearing siliceous surface of the silver transfer print is immediately adjacent to the coated front wall. Thereafter, the entire envelope is subjected to pressure, such as by passing it between V-ing rolls as described above, to provide the security bond. (The use of V-ing rolls to provide the necessary pressure gives the additional advantage that any excess activating solution can be forced out of the envelope by way of its open end.) Preferably, the envelope is then heatsealed along its remaining open side.

FIGURE- 6 is a section similar to that of FIGURE 5, showing the relationship of all of the elements when the completed laminate is prepared as just described. The final structure is an envelope or pouch comprising a transparent front wall 15, made up 0f an outer layer 10 of transparent hydroxylated polymer having a coating 9 on its inner surface of poly(methyl vinyl ether/maleic anhydride), to which is bonded the face lof a silver transfer print 8 in a security bond 16. Front wall 15 is heat, solvent, or adhesive-sealed at its periphery 16, and heatsealed at its periphery 17 to non-adhesive backing 14, to provide a tamper-proof lamination` having a security seal 18.

FIGURE 7 is a cross-section, greatly magnified, of a silver transfer image which is security-laminated in such a manner as to provide an embossable structure. The laminate as shown comprises a transparent rigid or semirigid embossable overlay 20, having a subcoat 19 cornprising a vinyl acetate-vinyl chloride copolymer, the lower surface 21 of which has been at least partially hydrolyzed, coated with a layer 9 of poly(methyl vinyl ether/maleic acid), and bonded to the image-bearing surface of a silver transfer print 8. It will be appreciated that such an embossable structure could readily comprise the front wall and bonded silver transfer image of the embodiment described as FIGURES 4 through 6 above. Thus, referring to FIGURES 5 and 6, the transparent hydroxylated polymer layer 10 could comprise a rigid or semi-rigid embossable vinyl overlay, having on its underside a subcoat of a surface-hydrolyzed vinyl acetate-vinyl chloride copolymer. The layer of poly(methyl vinyl ether/maleic acid) v9 is then coated onto the hydrolyzed surface of the subcoat. The envelope or pouch so prepared would thenbe characterized, not only as comprising a security-sealed silver transfer print but also as having an outer front surface which can be embossed with any desired indicia.

The following nonlimiting examples further illustrate the present invention:

EXAMPLE I A linear dichroic polyvinylene-polyvinyl alcohol light polarizing sheet having a cellulose acetate butyrate backing, commercially available from Polaroid Corporation, Cambridge, Mass., and designated as type KN42 was given a single coating with a No. 18 Meyer rod of a 10% by weight aqueous solution of high-molecular-weight poly- (methyl vinyl ether/maleic anhydride), commercially available from General Aniline & Film Corporation, New York, N.Y., under the trade name Gantrez AN-169, which coating was allowed to dry until all tackiness had disappeared. A silver transfer photographic print was made, using a Polaroid 3000 Speed Land Film Pack, Type 107. A drop of water was placed along one side of the print, and the print was then passed through V-ing rolls along with the prepared polarized sheet in such a way that the print surface was pressed firmly against the coated surface of the polarizer, forcing the water across the facing of the print between the surfaces bein-g pressed together. After a period of about 5 minutes an attempt was made to separate the print from its overlayer; 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 series of four laminations were prepared exactly as in Example I, with the exception that in place of the drop of water used to activate the coating, a drop of one of the following reagents was used:

Print (a): 5 0% solution of N-methyl pyrrolidone in water Print (b): 50% solution of methanol in water Print (c): 50% solution of 2-propanol in water Print (d): 50% solution of dioxane in water The security bond which was formed in each of the four laminations was found to be substantially identical to that formed in Example I, except that the setting times, that is, the time necessary for a security bond to be formed, were decreased. In prints (b) and (c), the setting time was observed to be slightly shorter than with water; in print (d), the setting time was shorter still. Print (a), using water and N-methyl-pyrrolidone, had the shortest setting time of all, the security bond being formed Valmost instantly upon the application of pressure to the laminate.

Nadeau,. and Carl 9 EXAMPLE n1 Two laminations were prepared in accordance with the procedure of Example I, except that the poly(methyl vinyl ether/maleic anhydride) coatings were applied to the polarizer overlay with a No. 9 and No. 3 Meyer rod respectively, to provide coatings of diminishing thickness; a 50% solution of N-methyl-pyrrolidone in water was used as the activating liquid. The laminations in both instances were substantially identical to that formed in Example I.

EXAMPLE IV A polyvinylene-polyvinyl alcohol sheet polarizer identical to that used in Example I was given a single coating with aNo. 18 Meyer rod of a 10% by weight-aqueous solution of the half methyl ester of a medium-molecularweight poly(methyl vinyl ether/maleic anhydride), .commercially available from General Aniline & Film Corporation under the trade name Gantrez AN-3391, which coating was allowed Vto dry. A silver transfer print was prepared as in Example I and was laminated to the coated polarizer as in Example I. The resulting lamination exhibited a security bond substantially identical to those of the lamination prepared in the foregoing examples.

EXAMPLE V A lamination was prepared exactly as in Example IV, except that a 50% aqueous solution of N-methyl pyrrolidone was used in place of water as the activating reagent. A security bond similar to those of the foregoing examples resulted.

EXAMPLE VI u A sheet comprising a celluloseacetate 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 coated on its poly- ,vinyl alcohol surface and laminated' to a silver transfer print exactly as in Example I, except that the activating reagent consisted of a 50% aqueous solution of N-methyl pyrrolidone. The security bond lfor-med Vwas substantially Aidentical tothat formed in the foregoing examples.

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

F. Smith.

lEXAMPLEy vnA A lamination, was prepared following the procedure of Example VIe,xcept that a medium molecular weight poly- (methylyinyl VVether/ maleic anhydride), commercially available from General Aniline & Film Corporation under the trade namek Gantrez AN-139, vwas used as the coating material. Asubstantially identical security bond was formed.

EXAMPLE VIII A lamination was prepared following the procedure of Example VI, except that a low molecular Weight poly- (methyl vinyl ether/ maleic anhydride), commercially available from General Aniline & Film Corporation under the trade name Gantrez AN-119, was used as the coating material. A substantially identical security bond was formed.

EXAMPLE IX A vinyl acetate-vinyl chloride copolymer was prepared by the following procedure: A Coke bottle was charged with the following:

De-oxygenated water mil-- 125 Sodium laurel sulfate g 1.25 Ammonium persulfate g 0.62

A, Example IX was coated with a 10% aqueous solution of The Coke bottle was sealed under an atmosphere of nitrogen and tumbled at 45 C. for about 21/2 hours. The resulting latex was coagulated with a small amount of concentrated hydrochloric acid. The coagulated copolymer was filtered, washed with water, dissolved in a mixture of acetone and methanol, precipitated into water, and dried.

The copolymer so prepared was dissolved in acetone, and coated onto one side of a high chloride-content vinyl acetate/ vinyl chloride rigid vinyl film, commercially available from Nixon Baldwin Co., Nixon, NJ. under the trade name Vynex, NHV 860 grade.

The outer surface of the copolymer subcoat was partially hydrolyzed by the following procedure: The entire film was immersed in a solution consisting of 500 g. of sodium hydroxide dissolved in 500 cc. of water and 500 cc. of methanol, for a period of about l5 seconds at about 40 C. The lm was then removed from the solution, washed With water until the surface of it was neutral, as determined with p-Hhydrion indicator paper, and dried.

The partially hydrolyzed subcoat surface was then coated with poly(methyl vinyl ether/maleic anhydride) and laminated to a silver transfer print with an activating reagent consisting of a 50% aqueous solution of 1-methyl- Z-pyrrolidoue, following the procedure of Example I. The laminate thus prepared exhibited a security bond substantially identical to those prepared in the foregoing examples.

Alternate procedures for subcoating vinyl sheets with vinyl acetate-vinyl chloride copolymers and surface-hydrolyzing the resulting material may be found in copending U.S. patent application Ser. No. 451,894 of Howard C. Haas and Harold O. Buzzell led Apr. 29, 1965.

EXAMPLE X A. hydrolyzed, subcoated vinyl film identical to that of the half methyl ester of medium-molecular-weight poly- (methyl vinyl ether/maleic anhydride) and laminated to a silver transfer print following the procedure of Example IX. A substantially identical securty bond was formed.

In the foregoing examples, the methyl vinyl ether/ maleic anhydride copolymers have been designated as low, medium, or high molecular weight; as is known to the art, these designations refer to materials havingl 'specific viscosities of 0.1-0.5, 1.0-1.4, and 2.6-3.5 respectively, as determined on a 1% solution of the copolymer in methyl ether ketone at 25 C.

After initial attempts yto 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 two hours.

(3) Suspended for 10 days over a hot, saturated sodium chloride solution.

(4) Refrigerated overnight.

(5) Stored at 100 F. and 80% 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 effect upon 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. It was also observed that the laminated silver transfer print exhibited no tendency to fade, even when subjected to sulfur and to accelerated aging conditions.

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.

Since certain changes may be made in the above process and products without departing from the scope of the .invention herein involved, it is intended that all matter vinyl ether-maleic acid copolymers of the formula:

OCH; 'I -oHz-CH-CH-CH loa'. 3:01

E H n and the partial lower alkyl esters thereof, and a third layer comprising a silver transfer print the surface of which is bonded to said second layer.

2. A laminar structure as defined in claim 1 wherein said transparent hydroxlyated polymer is polyvinyl alcohol.

3. A laminar structure as defined in claim 1 wherein said transparent hydroxylated polymer is a molecularlyoriented light-polarizing polyvinyl alcohol.

4. A laminar structure as defined in claim 1 wherein said transparent hydroxylated polymer is a partially hydrolyzed vinyl acetate-vinyl chloride copolymer.

5. A laminarstructure as defined in claim 1 wherein said transparent hydroxylated polymer is hydrolyzed cellulose acetate.

6. A laminar structure as defined in claim 1 wherein said first transparent layer comprises a cellulose acetate butyrate support having a first subcoat comprising cellulose nitrate, a second subcoat comprising cellulose nitrate and hydrolyzed polyvinyl acetate, and a third subcoat comprising polyvinyl alcohol.

7. A laminar structure as defined in claim 1 wherein said second layer consists essentially of the half methyl ester of poly(methyl vinyl ether/maleic acid).

8. A tamper-proof identification card comprising a laminar structure as defined in claim 1. l

9. The process for preparing a laminar structure which comprises coating a transparent sheet-like element at least one surface of which comprises a transparent hy droxylated polymer with a solution of a material consisting essentially of a compound selected from the group consisting of methyl vinyl ether-maleic acid copolymers of the formula:

l si. 'l.

and the partial lower alkyl esters thereof, said coating being applied to said hydroxylated polymeric surface of said transparent layer, drying the coating formed thereby, activating the surface of said coating with an aqueous activating solution and washing the image-bearing surface of a silver-transfer photographic print, and pressing the coated surface of said transparent sheet-like element onto said image-bearing surface.

10. The process as defined in claim 9 wherein said aqueous activating solution consists essentially of water.

11. The process as described in claim 9 wherein said aqueous activating solution comprises water and a swelling agent.

12. The process as defined in claim 11 wherein said swelling agent is N-methyl pyrrolidone.

13. The proceess as defined in claim 9 wherein said coating solution comprises an aqueous solution of a compound selected from the group consisting of methyl vinyl ether-maleic acid copolymer and the partial lower alkyl esters thereof.

14. The process for preparing a laminar structure which comprises coating the image-bearing surface of a silica aerogel stratum containing a silver-transfer print with an aqueous solution of a material consisting essentially of a compound selected from the group consisting of methyl vinyl ether-maleic acid copolymers of the formula:

and the partial lower alkyl estersthereof, and pressing the surface thus treated, whilev still wet, against a transparent hydroxylated polymeric surface of a transparent layer.

15. A laminar structure as defined in claim 1 wherein said first transparent layer comprises a vinyl acetate-vinyl chloride copolymer having a vinyl acetate to vinyl chloride ratio of from about 7:3 to 1:1, at least one surface of said layer being at least partially hydrolyzed, said transparent layer being bonded on its opposed surface to a high chloride content vinyl acetate-vinyl chloride embossable film.

References Cited UNITED STATES PATENTS 2,3 61,670 10/ 1944 Whitehead 402.2 2,558,857 7/ 1951 Land a c 96-29 2,719,791 10/ 1955 Land P--- 96-29 2,956,877 10/ 1960 Land et al 96-29 3,113,866 1.2/ 1963 Land 96-94 3,204,354 11/ 1965 Berger 40-2.2 3,219,445 11/ 1965 Lu Valle et al 96-76 3,3 1 3,1052 4/ 1967 Malster a 40-2.2 3,152,901 10/ 1964 Johnson 96-27 NORMAN G. TORCHIN, Primary Examiner J. E. CALLAGHAN, Assistant Examiner Us. Crxn. 96-.29

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