Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B42—BOOKBINDING; ALBUMS; FILES; SPECIAL PRINTED MATTER
  • B42D—BOOKS; BOOK COVERS; LOOSE LEAVES; PRINTED MATTER CHARACTERISED BY IDENTIFICATION OR SECURITY FEATURES; PRINTED MATTER OF SPECIAL FORMAT OR STYLE NOT OTHERWISE PROVIDED FOR; DEVICES FOR USE THEREWITH AND NOT OTHERWISE PROVIDED FOR; MOVABLE-STRIP WRITING OR READING APPARATUS
  • B42D25/00—Information-bearing cards or sheet-like structures characterised by identification or security features; Manufacture thereof
  • B42D25/40—Manufacture
  • B42D25/45—Associating two or more layers
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B42—BOOKBINDING; ALBUMS; FILES; SPECIAL PRINTED MATTER
  • B42D—BOOKS; BOOK COVERS; LOOSE LEAVES; PRINTED MATTER CHARACTERISED BY IDENTIFICATION OR SECURITY FEATURES; PRINTED MATTER OF SPECIAL FORMAT OR STYLE NOT OTHERWISE PROVIDED FOR; DEVICES FOR USE THEREWITH AND NOT OTHERWISE PROVIDED FOR; MOVABLE-STRIP WRITING OR READING APPARATUS
  • B42D25/00—Information-bearing cards or sheet-like structures characterised by identification or security features; Manufacture thereof
  • B42D25/30—Identification or security features, e.g. for preventing forgery
  • B42D25/36—Identification or security features, e.g. for preventing forgery comprising special materials
  • B42D25/364—Liquid crystals
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
  • B41M—PRINTING, DUPLICATING, MARKING, OR COPYING PROCESSES; COLOUR PRINTING
  • B41M3/00—Printing processes to produce particular kinds of printed work, e.g. patterns
  • B41M3/14—Security printing
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
  • B41M—PRINTING, DUPLICATING, MARKING, OR COPYING PROCESSES; COLOUR PRINTING
  • B41M5/00—Duplicating or marking methods; Sheet materials for use therein
  • B41M5/26—Thermography ; Marking by high energetic means, e.g. laser otherwise than by burning, and characterised by the material used
  • B41M5/28—Thermography ; Marking by high energetic means, e.g. laser otherwise than by burning, and characterised by the material used using thermochromic compounds or layers containing liquid crystals, microcapsules, bleachable dyes or heat- decomposable compounds, e.g. gas- liberating
  • B41M5/281—Thermography ; Marking by high energetic means, e.g. laser otherwise than by burning, and characterised by the material used using thermochromic compounds or layers containing liquid crystals, microcapsules, bleachable dyes or heat- decomposable compounds, e.g. gas- liberating using liquid crystals only
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B42—BOOKBINDING; ALBUMS; FILES; SPECIAL PRINTED MATTER
  • B42D—BOOKS; BOOK COVERS; LOOSE LEAVES; PRINTED MATTER CHARACTERISED BY IDENTIFICATION OR SECURITY FEATURES; PRINTED MATTER OF SPECIAL FORMAT OR STYLE NOT OTHERWISE PROVIDED FOR; DEVICES FOR USE THEREWITH AND NOT OTHERWISE PROVIDED FOR; MOVABLE-STRIP WRITING OR READING APPARATUS
  • B42D25/00—Information-bearing cards or sheet-like structures characterised by identification or security features; Manufacture thereof
  • B42D25/20—Information-bearing cards or sheet-like structures characterised by identification or security features; Manufacture thereof characterised by a particular use or purpose
  • B42D25/23—Identity cards
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B42—BOOKBINDING; ALBUMS; FILES; SPECIAL PRINTED MATTER
  • B42D—BOOKS; BOOK COVERS; LOOSE LEAVES; PRINTED MATTER CHARACTERISED BY IDENTIFICATION OR SECURITY FEATURES; PRINTED MATTER OF SPECIAL FORMAT OR STYLE NOT OTHERWISE PROVIDED FOR; DEVICES FOR USE THEREWITH AND NOT OTHERWISE PROVIDED FOR; MOVABLE-STRIP WRITING OR READING APPARATUS
  • B42D25/00—Information-bearing cards or sheet-like structures characterised by identification or security features; Manufacture thereof
  • B42D25/30—Identification or security features, e.g. for preventing forgery
  • B42D25/36—Identification or security features, e.g. for preventing forgery comprising special materials
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B42—BOOKBINDING; ALBUMS; FILES; SPECIAL PRINTED MATTER
  • B42D—BOOKS; BOOK COVERS; LOOSE LEAVES; PRINTED MATTER CHARACTERISED BY IDENTIFICATION OR SECURITY FEATURES; PRINTED MATTER OF SPECIAL FORMAT OR STYLE NOT OTHERWISE PROVIDED FOR; DEVICES FOR USE THEREWITH AND NOT OTHERWISE PROVIDED FOR; MOVABLE-STRIP WRITING OR READING APPARATUS
  • B42D25/00—Information-bearing cards or sheet-like structures characterised by identification or security features; Manufacture thereof
  • B42D25/40—Manufacture
  • B42D25/405—Marking
  • B42D25/415—Marking using chemicals
  • B42D25/42—Marking using chemicals by photographic processes
• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03C—PHOTOSENSITIVE MATERIALS FOR PHOTOGRAPHIC PURPOSES; PHOTOGRAPHIC PROCESSES, e.g. CINE, X-RAY, COLOUR, STEREO-PHOTOGRAPHIC PROCESSES; AUXILIARY PROCESSES IN PHOTOGRAPHY
  • G03C8/00—Diffusion transfer processes or agents therefor; Photosensitive materials for such processes
  • G03C8/42—Structural details
  • G03C8/423—Structural details for obtaining security documents, e.g. identification cards

Definitions

• the present invention relates to a process for the production of a laminated identification card (I.D. card).
• I.D. card laminated identification card
• I.D. cards essentially comprise a card or document usually containing information relating to the bearer. Generally, a portion of the information is in the form of a photograph of the bearer. I.D. cards are used e.g. to establish a person's authorization to conduct certain activities (driver's licence) or the authorization to have access to certain areas (employee I.D. cards) or to engage in credit transactions (I.D. credit cards).
• I.D. cards In view of the widespread use of I.D. cards, especially in commercial transactions, such as cashing checks, credit purchases, etc., it is important that the information contained in the I.D card cannot be altered and that the I.D. card gives maximum protection against counterfeiting, e.g. by photographic techniques and/or replacement of its data.
• a "security seal" is established between the information-bearing element of the card or document and the plastic.
• the security seal makes that if one should succeed in the removal of the plastic cover sheet also a substantial portion of the information containing part of the document should be removed too so that a damaged part remains adhering to the support. In this way a protection against mere substitution of information is obtained discouraging alteration of sealed documents.
• badges In order to improve the identification security coded information invisible to the naked eye and being machine readable is often included into the laminate serving as an identification card. So, e.g. badges have been made that include magnetically encoded data to be read by a magnetic signal detector as in a magnetic tape recorder or include infrared markings to be read with an infrared card reader as described e.g. in US-P 4,583,766.
• An other identification article described in published UK Patent Application 2 109 304 A and serving as identity document comprises markings or photograph, covered by a mask which is normally opaque but which upon applying a suitable electric field over a masking liquid crystal layer becomes at least translucent so that the covered material becomes visible.
• Magnetic, infrared or electro-optical markings that are not visible require special badge reading devices that are rather complicated and may be out of service for a while. Therefore, to enhance security there is a need for a hidden verification feature that can be made visible by man made inspection and turns back to the original hidden state after inspection with the advantage that such reversible state cannot be reproduced photographically which makes it impossible to duplicate the document by photographic copying.
• a laminated article containing visible information comprising two plastic resin sheets or layers at least one of which is transparent and having laminated inbetween at least one hydrophilic colloid layer containing photographically produced information and carrying or containing thermochromic liquid crystals of the cholesteric type in the form of a pattern or an indicium that can be made visible or obtains a change in colour by heating above 25 °C, said liquid crystals being arranged against a contrasting background having an optical density of at least 0.2 in its spectral absorption range.
• said background is black or dark blue coloured.
• liquid cristals of the cholesteric type is meant a chiral nematic liquid crystal material that has a natural twisted structure, the pitch of the twisted structure being of the order of the wavelengths of visible light.
• the pitch and period of the helical structure gives rise to interference colours when light falls on said liquid crystal material [ref. Scientific American, Vol. 222, April 1970, p. 102.]. Changes in temperature or pressure alter the pitch and period so that new colours are produced.
• Cholesteric liquid crystals can therefore serve as the active elements in devices that map the distribution of temperatures and are used e.g. in the thermochromic industry for the manufacture of digital thermometers and temperature indicators of one type or another.
• Thermochromic liquid crystals react to changes in temperature by changing colour. They do this by selectively reflecting a part of the visible light incident upon them, giving rise to reflection of almost all monochromatic colours.
• the reflected light varies with temperature characteristically from colourless to red at low temperatures, then through the colours of the visible spectrum to blue/violet and finally becomes colourless again at relatively high temperature.
• the thermochromic liquid crystal materials are viewed against a black background to absorb the unreflected light. For maximum apparent density in the eye a colour change producing green is preferred.
• thermochromic liquid crystals showing a temperature dependent change in colour are e.g. cholesteryl benzoate, cholesteryl chloride and anisylidene-p-aminophenylacetate. Below 32 °C the last-mentioned substance is a solid with gray appearance. Above that temperature it becomes a liquid crystal having colour, becoming colourless in the liquid state at 105 °C. By raising temperature the colour may change from red over yellow, green and blue to purple.
• thermochromic liquid crystals are present in the form of a fingerprint, signature, bar code, letter(s) and/or figure (s), line drawings etc.
• the pattern or indicium is either or not in the form of screen dots, which means that it is present either or not as a halftone pattern.
• thermochromic liquid crystals are present preferably on or in a hydrophilic colloid layer, e.g. a gelatin binder layer containing photographic information to be protected by lamination.
• the hydrophilic colloid layer containing photographic information is an imagewise exposed and processed (developed and fixed) silver halide emulsion layer or is an image-receiving layer containing a photographic image obtained by the silver complex diffusion transfer reversal process or a dye diffusion transfer process based on silver halide photography.
• any type of silver halide emulsion layer may be used.
• Information about silver halide emulsion preparation and composition can be found e.g. in Research Disclosure, December 1978, item 17643.
• composition of silver complex diffusion transfer reversal (DTR-) materials and processing are known e.g. from the book : “Photographic Silver Halide Diffusion Processes” by André Rott and Edith Weyde - Focal Press - London - New York (1972).
• gelatin is used preferably as hydrophilic colloid binder.
• Gelatin can, however, be replaced in part or integrallly by synthetic, semi-synthetic, or natural polymers.
• Synthetic substitutes for gelatin are e.g. polyvinyl alcohol, poly-N-vinyl pyrrolidone, polyvinyl imidazole, polyvinyl pyrazole, polyacrylamide, polyacrylic acid, and derivatives thereof, in particular copolymers thereof.
• Natural substitutes for gelatin are e.g. other proteins such as zein, albumin and casein, cellulose, saccharides, starch, and alginates.
• the semi-synthetic substitutes for gelatin are modified natural products e.g. gelatin derivatives obtained by conversion of gelatin with alkylating or acylating agents or by grafting of polymerizable monomers on gelatin, and cellulose derivatives such as hydroxyalkyl cellulose, carboxymethyl cellulose, phthaloyl cellulose, and cellulose sulphates.
• modified natural products e.g. gelatin derivatives obtained by conversion of gelatin with alkylating or acylating agents or by grafting of polymerizable monomers on gelatin
• cellulose derivatives such as hydroxyalkyl cellulose, carboxymethyl cellulose, phthaloyl cellulose, and cellulose sulphates.
• gelatin is used as sole binding agent for its physical development nuclei or in combination with alginic acid derivatives, polyvinyl alcohol, starch and starch derivatives, particularly carboxymethylcellulose or gallactomannans (ref. the above mentioned book of André Rott and Edith Weyde, p. 49).
• alginic acid derivatives polyvinyl alcohol, starch and starch derivatives, particularly carboxymethylcellulose or gallactomannans (ref. the above mentioned book of André Rott and Edith Weyde, p. 49).
• Other organic binding agents of the synthetic type are e.g. poly-N-vinylpyrrolidinone, copolymers of polyvinyl ester and maleic anhydride.
• colloidal silica has been mentioned, e.g. in US-P 2,698,237.
• a hydrophilic colloid binder preferably gelatin
• a mordant for the transferred dyes.
• the dye image-receiving layer contains basic polymeric mordants such as polymers of amino-guanidine derivatives of vinyl methyl ketone as described e.g. in US-P 2,882,156, and basic polymeric mordants and derivatives, e.g.
• poly-4-vinylpyridine the metho-p-toluene sulphonate of poly-2-vinylpyridine and similar compounds described in US-P 2,484,430, and the compounds described in the published DE-A 2,009,498 and 2,200,063.
• Other mordants are long-chain quaternary ammonium or phosphonium compounds or ternary sulphonium compounds, e.g. those described in US-P 3,271,147 and 3,271,148,, and cetyltrimethyl-ammonium bromide.
• Certain metal salts and their hydroxides that form sparingly soluble compounds with the acid dyes may be used too.
• the dye mordants are dispersed or molecularly divided in one of the usual hydrophilic binders in the image-receiving layer, e.g. in gelatin, polyvinylpyrrolidone or partly or completely hydrolysed cellulose esters.
• the production of colour photographs by the dye diffusion transfer process is a very convenient method especially for the production of identification cards containing a colour photograph of the person to be identified.
• the image-receiving layer can form part of a separate image-receiving material or form an integral combination with the light-sensitive layer(s) of the photographic material.
• an alkali-permeable light-shielding layer e.g. containing white pigment particles, is applied between the image-receiving layer and the silver halide emulsion layer(s) to mask the negative image with respect to the positive image as described e.g. in the already mentioned book of André Rott and Edith Weyde, page 141.
• the pattern or indicium of thermochromic liquid crystal material is applied by a spraying or a printing technique using an aqueous base ink containing the liquid crystals in dispersed state in a watersoluble polymeric binder e.g. gelatin or polyacrylamide.
• the pattern or indicium is applied to the layer containing the photographic information or other layer to be arranged inside the laminated article.
• Suitable printing techniques are offset printing, letter press printing or screen printing.
• the liquid crystal material is encapsulated in gelatin or gelatin derivative crosslinked with a hardener e.g. an aldehyde.
• a hardener e.g. an aldehyde.
• the encapsulation of the thermochromic liquid crystal material in gelatin derivatives the solubility of which is pH dependent may proceed as described e.g. in US-P 3,328,257. Operating with an aqueous ink containing gelatin-type microcapsules a good adherence to a hydrophilic colloid layer of the laminate is obtained.
• thermochromic liquid crystals are arranged against an underlying black area obtained by printing a black ink area or spot on a hydrophilic colloid layer prior to deposition of combination of dyes formed in the production of a photographic image.
• the black area is an area wherein black silver metal of sufficient optical density of a portrait obtained by silver halide photography is present.
• any type of paper support coated with a hydrophobic thermoplastic resin layer or any hydrophobic thermoplastic resin support may be used for coating thereon the imaging layer.
• a preferred resin support for use in lamination by heat-sealing is made of a vinyl chloride polymer.
• vinyl chloride polymer used herein includes the homopolymer, as well as any copolymer containing at least 50 % by weight of vinyl chloride units and including no hydrophilic recurring units.
• Vinyl chloride copolymers serving as the support may contain one or more of the following comonomers : vinylidene chloride, vinyl acetate, acrylonitrile, styrene, butadiene, chloroprene, dichlorobutadiene, vinyl fluoride, vinylidene fluoride and trifluorochloroethylene.
• the polyvinyl chloride serving as the support may be chlorinated to contain 60-65 % by weight of chlorine.
• polyvinyl chloride and its copolymers are improved by plasticization and their stability can be improved by stabilizers well known to those skilled in the art (see, e.g., F.W.Billmeyer, Textbook of Polymer Chemistry, Interscience Publishers, Inc., New York (1957) p. 311-315)).
• the polyvinyl chloride support may contain pigments or dyes as colouring matter e.g. in an amount up to 5 % by weight.
• An opaque white appearance may be obtained by incorporation of white pigments, e.g. titanium dioxide particles.
• the security sealing makes that if one should succeed in the removal of the plastic cover sheet also a substantial portion of the information and of the liquid crystals should be removed too with the partially torn off hydrophilic colloid layer, so that a damaged part remains adhering to the support.
• the hydrophilic colloid layer containing the photographic image and containing or carrying the thermochromic liquid crystal material is applied on an opaque polyvinyl chloride support having a thickness of only 0.150 to 0.75 mm.
• a sheet of that thickness can still be manipulated easily in a mechanical printing process, e.g. screen, offset or intaglio printing.
• security or verification marks in the form of e.g. an electronic integrated circuit pattern, a watermark, finger prints, printed patterns known from bank notes, coded information, e.g.
• binary code information, signature or other printed personal data or marks that may be applied with fluorescent pigments, nacreous pigments giving special light-reflection effects, and/or visibly legible or ultraviolet-legible printing inks as described e.g. in GB-P 1,518,946 and US-P 4,105,333 can be applied.
• Further security feature patterns can be made by mildly radioactive isotopes and holograms as described, e.g. in DE-OS 2 639 952, GB-P 1,502,460 and 1,572,442 and US-P 3,668,795.
• the holographic patterns may be obtained in silver halide emulsion layers, normally Lippmann emulsions, especially designed for that purpose and can either or not be combined with a photograph.
• the silver halide emulsion layer for producing the hologram is applied to one side of the transparent cover sheet used in the manufacture of a laminate according to the present invention and laminated together with the image containing layer either or not separated therefrom by a transparent resin intersheet made of polyethylene or a resin sheet such as a polyvinyl chloride sheet coated with polyethylene.
• the laminar article contains in that case preferably in the polyvinyl chloride support sheet, opacifying titanium dioxide and a suitable plasticizing agent.
• the support may be provided with an embossed structure.
• the lamination of the basic polyvinyl chloride sheet carrying the information to other polyvinyl chloride sheets in order to reach the required support thickness proceeds with poor adherence when chemicals used in or stemming from the photographic image processing, e.g. developing agent, are still present and soiling the sheets. Therefore, in order to obtain a better mutual adherence of polyvinyl chloride sheets a cleaning step is preceding the lamination for removing these chemicals.
• the cleaning proceeds preferably with the aid of a dissolved detergent that diminishes the surface tension in aqueous medium.
• a dissolved detergent that diminishes the surface tension in aqueous medium.
• Any commercial detergent can be used for that purpose.
• a survey of detergents can be found in the book : "McCutcheon's Detergents & Emulsifiers 1978 North American Edition - McCutcheon Division, MC Publishing Co. 175 Rock Road, Glen Rock, NJ 07452 USA.
• Preference is given to anionic and non-ionic surface-active agents containing a polyethyleneoxide chain in their structure. Examples of such agents are described in US-P 3,663,229.
• a preferred surfactant for the described purpose has the following structural formula and is called hereinafter surfactant A :
• the cleaning liquid contains also the self-cross-linking reaction product that improves in the lamination the adhesion of the information-carrying hydrophilic colloid layer(s) to the hydrophobic resin support and hydrophobic resin cover sheet.
• the hydrophobic resin cover sheet of the laminate consists preferably of a resin having a lower glass transition temperature (Tg) and melting temperature (Tm) than the resin present in the support sheet.
• the cover sheet is a polyethylene terephthalate resin sheet coated with a resinous melt-adhesive layer, e.g. a polyalkylene layer, preferably polyethylene layer, having a glass transition temperature at least 40°C lower than the glass transition temperature of the resin of the support sheet of the laminar article.
• the production of the laminar ID card proceeds by heat-sealing using heat and pressure.
• the polyvinyl chloride support coated with the hydrophilic imaging layer whereon the thermochromic liquid crystal has been printed is covered with a hydrophobic resin cover sheet as described above and pressed between flat plates under a pressure of e.g. 10 to 15 kg/m2 at a temperature in the range of 120 to 150 °C or by using a hot roller laminator known to those skilled in the art. Cooling proceeds preferably under pressure to avoid distortion.
• the laminate may contain the hydrophilic colloid imaging layer over the whole area of the support or in a part thereof, e.g. leaving free the edge area to allow direct fusion contact of the border area as described in US-P 4,425,421.
• An opaque polyvinyl chloride sheet having a thickness of 200 ⁇ m was treated with an electrical discharge produced by a corona-discharge apparatus operated under the following conditions : film-travelling speed : 20 m/min, electrode spacing to film surface : 2 mm, corona current : 0.55 A, AC-voltage difference (peak value) : 10 kV, frequency : 30 kHz.
• the corona-treated surface was coated with the following composition to form an image-receiving layer for silver complex diffusion transfer reversal (DTR-) processing : water 600 ml 3 % aqueous dispersion of colloidal Ag2S.NiS nuclei 14 ml 30 % aqueous dispersion of colloidal silica (average particle size 0.025 um, pH : 8) 250 ml 5 % solution in methanol of siloxane compound X 50 ml 4 % aqueous solution of formaldehyde 10ml 13.4 % aqueous dispersion of casein 200 ml 40 % aqueous dispersion of subbing ingredient S 100 ml water up to 1234 ml
• Said composition was applied at a wet coverage of 26 m2/l and dried.
• a black-and-white photographic silver halide emulsion material was exposed to produce thereon a negative latent image (portrait and graphic information).
• a black-and-white silver image serving for identification purposes was produced thereon.
• the treatment of the imaged image-receiving material with said liquid composition was carried out at 20 °C and lasted about 4 seconds.
• thermochromic micro-capsules dispersed in an aqueous solution of gelatin were applied by screen printing.
• the microcapsules were prepared as described in US-P 3,328,257 using anisylidene-p-aminophenylacetate in the hardened gelatin micro-envelopes.
• a transparent polyvinyl chloride sheet of 60 ⁇ m previously coated at one side with a transparent polyethylene sheet of 30 ⁇ m was laid and laminated with the polyethylene side in contact with the image-receiving layer.
• Flat steel plates were used for pressing the layers together under a pressure of 10 kg/cm2 at a temperature of 135°C.
• the obtained laminate contained at room temperature (20 °C) a visually hidden pattern of liquid crystal material that by raising the temperature above 35 °C changed its colour from red over yellow, green and blue to purple.
• An opaque polyvinyl chloride sheet containing dispersed titanium dioxide and having a thickness of 200 um was treated with an electrical discharge produced by a corona discharge apparatus operated under the following conditions : sheet travelling speed : 20 m/min, electrode spacing to sheet surface : 2 mm, corona current : 0.55 A, AC voltage difference (peak value) : 10 kV, frequency : 30 kHz.
• the corona-treated polyvinyl chloride sheet was coated with the following composition, the quantities being expressed per m2, to produce a subbing layer : gelatin 0.4 g 40 % aqueous dispersion of subbing ingredient S 5 ml 5 % solution in methanol of siloxane compound X 2.5 ml
• the dried subbing layer was coated with a dye image receiving layer from the following composition, the quantities likewise being expressed per m2 : gelatin 0.9 g mordant M 2.25 g
• the dye image receiving sheet was processed in combination with a photographic dye diffusion transfer material as described in the Example of US-P 4,496,645. Said photographic material was imagewise exposed and subsequently contacted for 1 minute with the dye image receiving material having the composition described above in a diffusion transfer apparatus COPYPROOF CP 38 (trade name of Agfa-Gevaert N.Y. Belgium) ) having in its tray an alkaline basic processing liquid of the following composition : water 800 ml sodium hydroxide 25 g sodium orthophosphate 25 g cyclohexane dimethanol 25 g 2,2'-methylpropylpropane diol 25 g N-ethylbenzene-pyridinium chloride 0.5 g distilled water up to 1000 ml
• thermochromic micro-capsules dispersed in an aqueous solution of gelatin were applied by screen printing.
• the microcapsules were prepared as described in US-P 3,328,257 using anisylidene-p-aminophenylacetate in the hardened gelatin micro-envelopes.
• a transparent cover sheet being a polyethylene terephthalate sheet having a thickness of 30 ⁇ m and being coated at one side with a thermoadhesive layer of polyethylene having a thickness of 30 ⁇ m.
• the lamination was carried out between flat steel plates pressing the polyethylene and image-bearing layers together for 5 minutes using a pressure of 10 kg/cm2 at a temperature of 135 °C. Said pressure was maintained during cooling to reach room temperature (20 °C) again.
• the obtained laminate had a sealing thus strong that even after having been immersed in water for two days the sheet elements could not be peeled apart.
• reaction product 2 obtained as a 10 % by weight solution according to GB-P 1 269 381.
• reaction product R a mixture of the polyamide defined as reaction product 1 in said GB-P and methyl-bis-(3-amino-propyl)-amine were reacted with epichlorohydrin.
• “Subbing ingredient S” is the reaction product of :
• Subbing ingredient S is used as a dispersion in water containing 7.5 % by weight of N-methylpyrrolidinone.
• Mordant M has the following structure (the percentage values are mole %) :

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• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Manufacturing & Machinery (AREA)
• Crystallography & Structural Chemistry (AREA)
• Physics & Mathematics (AREA)
• Computer Security & Cryptography (AREA)
• Optics & Photonics (AREA)
• Architecture (AREA)
• Structural Engineering (AREA)
• General Physics & Mathematics (AREA)
• Chemical Kinetics & Catalysis (AREA)
• General Chemical & Material Sciences (AREA)
• Credit Cards Or The Like (AREA)
• Laminated Bodies (AREA)

Priority Applications (3)

Applications Claiming Priority (1)

Publications (2)

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Family Applications (1)

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• 1989
  • 1989-05-31 DE DE68917916T patent/DE68917916T2/de not_active Expired - Fee Related
  • 1989-05-31 EP EP89201383A patent/EP0400220B1/en not_active Expired - Lifetime
• 1990
  • 1990-05-29 JP JP2141240A patent/JPH0342295A/ja active Pending

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