# US 10,870,307 B2 · Security pigment based on core-shell particles, and production method > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,870,307 B2 - Document ID: US10870307B2 - Status: Granted - Kind: B2 - Application number: 15/774,137 - Filed: 2016-11-09 - Published: 2018-11-01 - Granted: 2020-12-22 - Earliest claimed: 2015-11-11 - Assignees: Giesecke+Devrient Currency Technology GmbH - Applicants: Giesecke+Devrient Currency Technology GmbH - Inventors: Johann Kecht; Axel Schlossbauer - Web page: https://patentgrep.com/patent/US10870307B2 ## CPC - B42D 25/378: Special inks - B01J 13/04: by physical processes, e.g. drying, spraying - B01J 13/16: Interfacial polymerisation - B01J 13/18: In situ polymerisation with all reactants being present in the same phase - B01J 13/206: {Hardening; drying} - B01J 13/22: Coating - B42D 25/355: Security threads - B42D 25/373: Metallic materials - B42D 25/382: absorbing or reflecting infrared light - B42D 25/387: absorbing or reflecting ultraviolet light - C08K 3/013: Fillers, pigments or reinforcing additives - C08K 5/0041: {Optical brightening agents, organic pigments} - C08L 25/06: Polystyrene - C08L 33/12: Homopolymers or copolymers of methyl methacrylate - C08L 61/06: of aldehydes with phenols - C08L 61/12: with polyhydric phenols - C08L 61/24: with urea or thiourea - C08L 61/28: with melamine - C08L 61/30: of aldehydes with heterocyclic and acyclic or carbocyclic compounds - C08L 61/34: Condensation polymers of aldehydes or ketones with monomers covered by at least two of the groups C08L61/04, C08L61/18 and C08L61/20 - C09B 67/0013: {with polymeric coatings} - C09B 67/0033: {Blends of pigments; Mixtured crystals; Solid solutions} - C09B 67/0097: {Dye preparations of special physical nature; Tablets, films, extrusion, microcapsules, sheets, pads, bags with dyes} - C09D 11/037: characterised by the pigment - C09D 11/50: Sympathetic, colour changing or similar inks - C09K 11/02: Use of particular materials as binders, particle coatings or suspension media therefor - C09K 11/025: {non-luminescent particle coatings or suspension media} - C09K 11/06: containing organic luminescent materials - D21H 21/30: Luminescent or fluorescent substances, e.g. for optical bleaching (D21H21/40 takes precedence) - D21H 21/40: Agents facilitating proof of genuineness or preventing fraudulent alteration, e.g. for security paper (watermarking B41M3/10, D21F1/44; security printing B41M3/14; securities or banknotes characterised by colour effects B42D25/29, B42D25/30; testing paper currency or valuable papers for genuineness G07D7/00) - G07D 7/003: {using security elements (using digital security elements G07D7/004)} - G07D 7/1205: Testing spectral properties - B42D 25/29: Securities; Bank notes - G07D 2207/00: Paper-money testing devices - 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 - B01J: CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS - C08K: Use of inorganic or non-macromolecular organic substances as compounding ingredients (paints, inks, varnishes, dyes, polishes, adhesives C09) - C08L: COMPOSITIONS OF MACROMOLECULAR COMPOUNDS (compositions based on polymerisable monomers C08F, C08G; artificial filaments or fibres D01F; textile treating compositions D06) - C09B: ORGANIC DYES OR CLOSELY-RELATED COMPOUNDS FOR PRODUCING DYES {, e.g. PIGMENTS}; MORDANTS; LAKES (fermentation or enzyme using processes to synthesise a desired chemical compound C12P) - C09D: COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR (cosmetics A61K; processes for applying liquids or other fluent materials to surfaces, in general, B05D; staining wood B27K5/02; glazes or vitreous enamels C03C; natural resins, French polish, drying-oils, driers, turpentine, per se, C09F; polishing compositions other than French polish, ski waxes C09G; adhesives or use of materials as adhesives C09J; materials for sealing or packing joints or covers C09K3/10; materials for stopping leaks C09K3/12; processes for the electrolytic or electrophoretic production of coatings C25D) - C09K: MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE - D21H: PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR - G07D: HANDLING OF COINS OR VALUABLE PAPERS, e.g. TESTING, SORTING BY DENOMINATIONS, COUNTING, DISPENSING, CHANGING OR DEPOSITING ## Abstract The invention relates to a security pigment of core-shell particles, comprising a core based on a thermoplastic material, a shell based on a condensation polymer, and an organic or metalorganic feature substance present in dissolved or finely distributed form in the core, wherein the mass fraction of the shell amounts to more than 25%, preferably 50%, particularly more than 100%, in relation to the mass of the core. The invention further relates to a method for producing the core-shell particles and to value documents having the core-shell particles. ## Claims ### Claim 1 A security pigment comprising chemically stable core-shell particles, each of the core-shell particles comprising a core based on a thermoplastic polymer, a shell based on a condensation polymer, and an organic or metalorganic feature substance present in dissolved or finely distributed form in the core, wherein the mass fraction of the shell amounts to more than 25%, relative to the mass of the core, such that the core-shell particles are chemically stable, and wherein the condensation polymer includes an aminoplast, a phenoplast, a melamine-formaldehyde resin (MF), a melamine-phenol-formaldehyde resin (MPF), a phenol-formaldehyde resin (PF), a urea-formaldehyde resin (UF), a melamine-guanidine-formaldehyde resin, or a phenol-resorcin-formaldehyde resin. ### Claim 2 (depends on 1) The security pigment according to claim 1, wherein the thermoplastic polymer includes polystyrene (PS), a polyacrylate, a polyethylene (PE), a polypropylene (PP), a polycarbonate (PC), a polyamide (PA), a polyurethane (PU), a polyurea (PH), polyethylene terephthalate (PET) or another polyester, polyacrylates polymethyl methacrylate (PMMA), polyvinyl acetate (PVAC), polyvinyl chloride (PVC), or polyacrylonitrile (PAN). ### Claim 3 A security pigment comprising chemically stable core-shell particles, each of the core-shell particles comprising a core based on a thermoplastic polymer, a shell based on a condensation polymer, and an organic or metalorganic feature substance present in dissolved or finely distributed form in the core, wherein the mass fraction of the shell amounts to more than 25%, relative to the mass of the core such that the core-shell particles are chemically stable, and wherein the condensation polymer is selected from aminoplasts, phenoplasts, melamine-formaldehyde resins (MF), melamine-phenol-formaldehyde resins (MPF), phenol-formaldehyde resins (PF), urea-formaldehyde resins (UF), melamine-guanidine-formaldehyde resins or phenol-resorcin-formaldehyde resins. ### Claim 4 (depends on 1) The security pigment according to claim 1, wherein each of the core-shell particles comprise exactly one core and a shell. ### Claim 5 (depends on 1) The security pigment according to claim 1, wherein the core-shell particle comprises several core portions and a shell surrounding the several core portions. ### Claim 6 (depends on 1) The security pigment according to claim 1, wherein the feature substance is present in the thermoplastic polymer in dissolved form. ### Claim 7 (depends on 1) The security pigment according to claim 1, wherein the feature substance is a fluorescent or phosphorescent or photochromic or thermochromic feature substance or a UV or IR or VIS absorption dye. ### Claim 8 (depends on 1) The security pigment according to claim 1, wherein the feature substance is a fluorescent or phosphorescent feature substance that is excitable in the UV spectral range, at a wavelength of 365 nm, and emits in the visible spectral range. ### Claim 9 (depends on 1) The security pigment according to claim 1, wherein the feature substance is a fluorescent or phosphorescent feature substance that emits in the IR spectral range. ### Claim 10 (depends on 1) The security pigment according to claim 1, wherein at least two different luminescent dyes are present in finely distributed or dissolved form in the core, which form an energy transfer system in which the first luminescent dye, after excitation, transfers its excitation energy partially or completely to the second luminescent dye. ### Claim 11 (depends on 1) The security pigment according to claim 1, wherein the security pigment is stable against toluene, ethyl acetate, hydrochloric acid (5%), sodium hydroxide solution (2%) and sodium hypochlorite solution (5% active chlorine) in accordance with the test method A5, and wherein the feature intensity remaining after the test is higher than 80% of the initial intensity. ### Claim 12 (depends on 1) The security pigment according to claim 1, wherein the security pigment is stable against acetone in accordance with test method A5, and wherein the feature intensity remaining after the test is higher than 80% of the initial intensity. ### Claim 13 A method for producing a security pigment of core-shell particles, each of the core-shell particles being produced to comprise a solid core based on a thermoplastic polymer, a shell based on a condensation polymer, and an organic or metalorganic feature substance present in dissolved or finely distributed form in the core, the method comprising: a) dissolving the feature substance together with the thermoplastic polymer in an organic solvent and dispersing the obtained solution in water by means of a surfactant; b) supplying at a certain pH value prepolymer units to be polymerized in a condensation reaction such that condensation of the shell-forming polymer around the dispersed droplets of the organic solvent is achieved; and c) removing the organic solvent such that the core-shell particles are formed with a solid core; wherein the mass fraction of the shell amounts to more than 25%, relative to the mass of the core, such that the core-shell particles are chemically stable, and wherein the condensation polymer includes an aminoplast, a phenoplast, a melamine-formaldehyde resin (MF), a melamine-phenol-formaldehyde resin (MPF), a phenol-formaldehyde resin (PF), a urea-formaldehyde resin (UF), a melamine-guanidine-formaldehyde resin, or a phenol-resorcin-formaldehyde resin. ### Claim 14 A method for producing a security pigment of core-shell particles, each of the core-shell particles being produced to comprise a solid core based on a thermoplastic polymer, a shell based on a condensation polymer, and an organic or metalorganic feature substance present in dissolved or finely distributed form in the core, the method comprising: a) preparing the core based on a thermoplastic polymer, in which the feature substance is present in dissolved or finely distributed form, wherein the thermoplastic polymer has functional groups on its outside, which are suitable for prepolymer units to bind thereto covalently for preparing the shell; b) preparing the shell from prepolymer units polymerizing in a condensation reaction, said units growing directly to the core through reaction with the functional groups of the thermoplastic core, wherein the mass fraction of the shell amounts to more than 25%, relative to the mass of the core, such that the core-shell particles are chemically stable, and wherein the condensation polymer includes an aminoplast, a phenoplast, a melamine-formaldehyde resin (MF), a melamine-phenol-formaldehyde resin (MPF), a phenol-formaldehyde resin (PF), a urea-formaldehyde resin (UF), a melamine-guanidine-formaldehyde resin, or a phenol-resorcin-formaldehyde resin. ### Claim 15 (depends on 14) The method according to claim 14, wherein the functional groups are selected from amine groups, amide groups, isocyanate groups, aldehyde groups or hydroxyl groups. ### Claim 16 (depends on 14) The method according to claim 14, wherein the functional groups are present at the outer surface of the core based on the thermoplastic polymer at a concentration of 0.1 nmol/cm2 to 10 nmol/cm2. ### Claim 17 A method for producing a security pigment of core-shell particles, each of the core-shell particles being produced to comprise a solid core based on a thermoplastic polymer, a shell based on a condensation polymer, and an organic or metalorganic feature substance present in dissolved or finely distributed form in the core, the method comprising: a) dissolving an organic or metalorganic feature substance in a thermoplastic polymer to supply in this manner thermoplastic particles with feature substance dissolved therein; and b) incorporating the thermoplastic particles with feature substance dissolved therein obtained in step a) in a duromer matrix, c) grinding the product obtained in step b) to pigment particles, wherein the mass fraction of the shell amounts to more than 25%, relative to the mass of the core, such that the core-shell particles are chemically stable, and wherein the condensation polymer includes an aminoplast, a phenoplast, a melamine-formaldehyde resin (MF), a melamine-phenol-formaldehyde resin (MPF), a phenol-formaldehyde resin (PF), a urea-formaldehyde resin (UF), a melamine-guanidine-formaldehyde resin, or a phenol-resorcin-formaldehyde resin. ### Claim 18 (depends on 17) The method according to claim 17, wherein the thermoplastic particles with feature substance dissolved therein supplied in step a) are produced as follows: dissolving the feature substance together with the thermoplastic polymer in an organic solvent and dispersing the obtained solution in water by means of a surfactant, followed by removing the organic solvent; or incorporating the feature substance in the thermoplastic polymer in the melt, with an extruder, followed by grinding of the solidified polymer. ### Claim 19 (depends on 13) The method according to claim 13, wherein the feature substance is a fluorescent or phosphorescent or photochromic or thermochromic feature substance or a UV or IR or VIS absorption dye. ### Claim 20 (depends on 13) The method according to claim 13, wherein the security pigment is stable against toluene, ethyl acetate, hydrochloric acid (5%), sodium hydroxide solution (2%) and sodium hypochlorite solution (5% active chlorine) in accordance with test method A5, wherein the feature intensity remaining after the test is higher than 80% of the initial intensity. ### Claim 21 (depends on 13) The method according to claim 13, wherein the security pigment is stable against acetone in accordance with the test method A5, wherein the feature intensity remaining after the test is higher than 80% of the initial intensity. ### Claim 22 (depends on 1) An ink concentrate or printing ink for offset printing, screen printing or steel intaglio printing with a security pigment according to claim 1. ### Claim 23 (depends on 1) A polymer composition with a security pigment according to claim 1, wherein the polymer composition is present in the form of a value document substrate, a security foil, a mottling fiber or a security thread. ### Claim 24 (depends on 1) A value document, mottling fiber, security thread or security foil with a security pigment according to claim 1.