RU2779487C1 - Paper bases containing surfactant pigments and methods for making and using the same - Google Patents

Abstract

FIELD: paper bases.

SUBSTANCE: paper bases are proposed that contain latent marking pigments (CMP), which are one or more infrared (IR) anti-Stokes pigments. Also proposed is a method for obtaining a paper base with hidden markings and a method for determining whether a sheet paper base is a genuine document. A latent marking pigment is used, characterized by a particle size in the range from about 0.1 mcm to about 5 µm and introduced into the paper base in an amount detectable in the IR range from about 2 mg/m² to about 10 mg/m², while the latent marking pigment is one or more IR anti-Stokes shift pigments selected from one or more of: yttrium oxide; double sodium-yttrium fluoride; lanthanum oxide; lanthanum fluoride; yttrium oxysulfide; lanthanum oxysulfide; gadolinium (Gd2O2S); ytterbium (Yb) or mixtures thereof.

EFFECT: elimination of visible staining and discoloration of IR inks.

20 cl, 2 tbl

Description

FIELD OF TECHNOLOGY TO WHICH THE INVENTION RELATES

[0001] The present invention relates broadly to paper substrates (including sheet paper substrates) that contain latent marking (CMP) pigments, which are one or more infrared (IR) anti-Stokes pigments. The present invention also relates broadly to methods for incorporating such CMP into a paper substrate, other than a technical solution involving printing, for example using a size press or spraying. The present invention further relates broadly to methods for identifying the presence of such CMPs incorporated into a sheet paper substrate using an infrared (IR) pigment sensor, such as a copier or printer, to control the amount of printer pigment deposited onto the sheet paper substrate. , or determining whether the sheet paper base is a genuine or counterfeit document.

BACKGROUND OF THE INVENTION

[0002] In recent years, there has been an ever-increasing need for effective "invisible paint" compositions. "Invisible paint" compositions include a broad class of paint compositions that are invisible or minimally visible to the naked eye when applied, for example, to a paper base and viewed with "natural light" (e.g., sunlight) or light from traditional lamps, or other visible light sources. . These forms of visible light may be collectively referred to as "white light", which contains a combination of various colored light components generally within a wavelength range, eg, from about 300 nm to about 700 nm. Under such lighting conditions, "invisible paint" compositions are either colorless or substantially colorless. It is only due to illumination from outside the visible light spectrum that the images printed by such "invisible ink" compositions become visible or otherwise detectable with or without the assistance of ancillary observation equipment such as a detector, sensor, scanner, etc. See U.S. Patent No. 6,149,719 (Houle), issued November 21, 2000.

[0003] Applications of "invisible paint" compositions may vary. For example, "invisible ink" compositions can provide many benefits when printed on a variety of paper-based documents such as insurance policies, receipts, and so on. For example, invisible ink compositions can be used on paper-based documents produced by financial or investment institutions (for example, checks, account statements, travel documents, banknotes, securities, bonds, certificates, vouchers, etc.), merchants issuing entrance tickets to events, by governments issuing identification documents such as passports, by manufacturers on packages, labels, etc. products, etc. Such paper-based documents may contain a wide variety of route codes, numeric identifiers, data lists, etc., which remain invisible to the naked eye under "white light", but are visible when illuminated, detected, scanned, etc. light other than "white light" in order to determine whether these paper-based documents are genuine or fake, to display information, data, etc., present on paper-based documents, only to certain recipients of such documents, etc. , consumers, etc. For example, it may be necessary to enter a barcode on such paper-based documents for inventory management, product assembly applications in factories, etc., where a particular barcode does not appear in visible form on such products, packaging, labels, etc. etc., which are subject to processing. See U.S. Patent No. 6,149,719 (Houle), issued November 21, 2000.

[0004] Additionally, for banknotes, securities, bonds, certificates, vouchers, checks, valuable admission tickets and other paper-based documents of value, such as passports and other identification documents, as well as for product security features such as labels, printing, packaging, etc., there may be a risk of counterfeiting. There are several ways to check whether such documents are genuine or fake, ranging from simple to complex. Some methods include indistinguishable (ie, hidden) elements that can be introduced into such documents, for example by applying invisible ink compositions. These hidden features can be created by printing these invisible ink compositions on the document paper in a specific pattern, in a specific order, and so on. Because these hidden elements are undetectable, invisible, etc. by the human eye, for detection, identification, display, etc. these hidden elements, detectors, sensors, scanning devices, etc. can be used to authenticate such documents. See U.S. Patent No. 6,149,719 (Houle), issued November 21, 2000.

[0005] While invisible paint compositions contain materials with at least some absorption of light outside the visible bandwidth, they may also contain visible color imparting materials (sometimes referred to as "interference") that can make the invisible paint composition usable. for use only in more limited conditions. For example, one such invisible ink composition employs an infrared (IR) ink that absorbs IR radiation having a wavelength of 793 nm and emits IR radiation with a longer wavelength of 840 nm as fluorescence. Since this ink has a pale green appearance, it may be necessary to reduce the density of the ink to maintain invisibility, which, however, also makes it more difficult to detect features printed with this ink. Additionally, detection of such paints may require both a special radiation source and an imaging device. In another example of an invisible paint composition, a silicon naphthalocyanine-based IR absorbing ink is used to provide a slight change in the absorption of 790 nm light that can be detected using a 790 nm light source. This slight change in IR absorption is also limited in part by visible "interference" since this particular paint dye is not truly invisible, but also has a visible green tint. Additionally, "noise" due to paint dye absorption in the visible region in the IR spectrum can mask or make it difficult for a given weak IR absorption signal. However, increasing the IR absorption density to improve signal detection may be limited as "noise" in the visible absorption region may also increase. Additionally, such dyes or pigments for IR ink can be unstable, especially when used at low concentrations, and therefore vulnerable to degradation under environmental conditions, including high humidity, or fading of the dye for ink when exposed to UV or visible radiation. . See U.S. Patent No. 8,941,886 (Kurtz et al), issued January 27, 2015.

[0006] Invisible ultraviolet (UV) paint compositions have also been used, such as paints in which incident UV radiation excites visible fluorescence. These UV-excited inks are displayed when illuminated by special light sources such as black light lamps or UV LEDs that provide either UVA (wavelength 315-400nm) or UVB (wavelength 280-315nm) radiation. Since solar UV radiation passes up to 280 nm when filtered by the atmosphere, there may be a risk of accidentally activating and displaying elements when using these ultraviolet (UV) inks. See U.S. Patent No. 8,941,886 (Kurtz et al), issued January 27, 2015.

SUMMARY OF THE INVENTION

[0007] According to a first general aspect of the present invention, there is provided an article in the form of a hidden label paper base, comprising:

paper base;

and a water mark pigment having a particle size in the range of about 0.1 micron to about 5 micron and incorporated into the base paper in an IR detectable amount in the range of about 0.1 mg/m ² to about 1000 mg /m ² , while the pigment for latent marking is one or more pigments with anti-Stokes shift in the IR spectrum, selected from one or more of: yttrium oxide; double sodium-yttrium fluoride; lanthanum oxide; lanthanum fluoride; yttrium oxysulfide; lanthanum oxysulfide; gadolinium (Gd2O2S); ytterbium (Yb) or mixtures thereof.

[0008] According to a second general aspect of the present invention, there is provided a method for manufacturing a hidden marking paper base, the method comprising the following steps:

(a) providing a composition comprising a watermarking pigment having a particle size in the range of about 0.1 micron to about 5 microns, wherein the watermarking pigment is one or more IR anti-Stokes shift pigments selected from one or more of: yttrium oxide; double sodium-yttrium fluoride; lanthanum oxide; lanthanum fluoride; yttrium oxysulfide; lanthanum oxysulfide; gadolinium (Gd2O2S); ytterbium (Yb) or mixtures thereof; and

(b) incorporating the composition of step (a) via a non-printing solution into the sheet paper base in an IR detectable amount in the range of about 0.1 mg/m ² to about 1000 mg/m ² .

[0009] According to a third general aspect of the present invention, there is provided a method for controlling the amount of printer pigment deposited on a sheet paper substrate, the method comprising the steps of:

(a) providing a sheet paper base with hidden markings, while the sheet paper base with hidden markings contains:

sheet paper base; and

a latent marking pigment having a particle size in the range of about 0.1 micron to about 5 micron and incorporated into the sheet paper base in an IR detectable amount in the range of about 0.1 mg/m ² to about 1000 mg /m ² , and a method identifying the type of sheet paper base with a latent marking, while the pigment for latent marking is one or more pigments with anti-Stokes shift in the IR spectrum, selected from one or more of: yttrium oxide; double sodium-yttrium fluoride; lanthanum oxide; lanthanum fluoride; yttrium oxysulfide; lanthanum oxysulfide; gadolinium (Gd2O2S); ytterbium (Yb) or mixtures thereof;

(b) scanning the labeled paper base sheet according to step (a) with an IR pigment sensor to identify the type of the labeled paper substrate; and

(c) adjusting the amount of printer pigment deposited on the flush mark paper substrate in response to the identification in step (b) of the type of the flush mark paper substrate.

[0010] According to a fourth general aspect of the present invention, there is provided a method for determining whether a base paper sheet is a genuine document, the method comprising the following steps:

(a) providing a sheet paper base; and

(b) scanning the base paper sheet with an IR pigment sensor to detect the presence or absence of a particular smudge pigment being introduced into the base paper sheet, wherein the smudge pigment is one or more anti-Stokes shift pigments selected from one or more from: yttrium oxide; double sodium-yttrium fluoride; lanthanum oxide; lanthanum fluoride; yttrium oxysulfide; lanthanum oxysulfide; gadolinium (Gd2O2S); ytterbium (Yb) or mixtures thereof;

however, if the IR pigment sensor detects that the base paper sheet: (i) contains a certain latent marking pigment, then the sheet paper base is identified as genuine; or (ii) does not contain a specified latent marking pigment, then the paper backing sheet is identified as counterfeit.

DETAILED DESCRIPTION

[0011] It is advantageous to define certain terms before describing the invention. It should be understood that the following definitions are used throughout this specification.

Definitions

[0012] If the definition of terms goes beyond the commonly used meaning of this term, the applicant intends to use the definitions below, unless specifically indicated.

[0013] For the purposes of the present invention, the term "latent marking pigment (CMP)" refers to a composition, compound, substance, material, etc., which is colorless or nearly colorless in the visible spectrum, but visible in infrared (IR) spectrum. For the purposes of the present invention, the term "certain mark-on pigment" refers to a particular mark-on pigment containing a known type of mark-on pigment that the pigment's IR sensor is configured to detect.

[0014] For purposes of the present invention, the term "IR anti-Stokes shift pigment" refers to CMP, which is an upconverting phosphorus that absorbs infrared (IR) radiation but emits visible radiation. Suitable anti-Stokes shift pigments may include, for example, one or more of: yttrium oxide; double sodium-yttrium fluoride; lanthanum oxide; lanthanum fluoride; yttrium oxysulfide; lanthanum oxysulfide; etc. These anti-Stokes shift pigments can also be doped with one or more other rare earth elements such as ytterbium, erbium, thulium, holmium, etc. See U.S. Patent Application No. 20170369777 (Collins et al), published December 28, 2017, the entire content and disclosure of which, in particular paragraphs [0035]-[0037], are incorporated herein by reference.

[0015] For the purposes of the present invention, the term "visible light spectrum" refers to the spectrum of radiation, characterized by a wavelength in the range from about 400 nm to about 700 nm.

[0016] For the purposes of the present invention, the term "infrared (IR) spectrum" refers to a spectrum of radiation having a wavelength greater than about 700 nm and typically in the range greater than about 700 nm to about 1 mm.

[0017] For the purposes of the present invention, the term "ultraviolet (UV) radiation spectrum" refers to a spectrum of radiation having a wavelength of less than about 400 nm. The UV spectrum can be divided into the long wavelength UV (UVA) spectrum (wavelength in the range from about 315 nm to about 400 nm), the mid-wave UV (UVB) spectrum (wavelength in the range from about 280 nm to approximately 315 nm) and a short wavelength UV (UVC) spectrum (wavelength ranging from approximately 100 nm to approximately 280 nm).

[0018] For the purposes of the present invention, the term “IR detectable amount” refers to the amount of anti-Stokes shifted pigment in the IR spectrum that can be detected by an IR sensor when introduced into a paper base using a non-printing solution. .

[0019] For the purposes of the present invention, the term "IR pigment sensor" refers to a sensor capable of detecting the presence of an anti-Stokes shifted pigment in the IR spectrum. The IR pigment sensor contains an excitation element that excites a pigment with an anti-Stokes shift in the IR spectrum and causes its luminescence within a certain wavelength range, as well as a detector element that is configured to detect (recognize) this luminescence within a given wavelength range . The exciter and detector elements may be included as a single component, or may be separate components that operate in conjunction with each other during operation of the IR pigment sensor. The IR pigment sensor may also be a separate piece of equipment, or may be an attachment for a printer, copier, scanner, multifunction copier/printer/scanner/fax machine, etc. Suitable pigment IR sensors may include: NTE3033 infrared LEDs from NTE Electronics, Inc., Bloomfield; New York; infrared LED emitter and detector RadioShack from SparkFun Electronics; Grove Infrared Reflective Sensor v1.2 from Seeed Studio or Arduino; etc.

[0020] For the purposes of the present invention, the term "non-printing solution" refers to a method for incorporating a latent marking pigment (CMP) into a paper substrate other than printing CMP on a paper substrate. Suitable non-printing solutions for incorporating CMP into a paper substrate may include, for example, applying CMP on a size press, eg as part of a sizing composition, by spraying CMP onto the paper substrate; by introducing into the fibrous papermaking material in the wet end of the paper machine; by pour coating; by introducing into the fibrous papermaking material in the headbox; by introducing into the fibrous papermaking material at other compression points; by bonding with fibers to make paper; by applying the method disclosed in U.S. Patent Application No. 20170037578 (Skaggs et al), published February 9, 2017 (the entire disclosure and contents of which are incorporated herein by reference), which involves separately treating one or both surfaces of the paper substrate with an optical bleach (OVA) and a polyvalent metal salt desiccant, wherein one or both surfaces of the paper base of the paper base are treated with one of these two agents on the size press, and the surface(s) are treated with the second of these two agents before or after the size press , but with the replacement of OVA with CMP; etc.

[0021] For the purposes of the present invention, the term "random" refers to the distribution of CMP in a manner that is an unrecognizable (e.g., non-repeating) pattern, such as distribution of CMP without placement at constant and/or equalized distances, etc.

[0022] For the purposes of the present invention, the term "pseudo-random" refers to the distribution of CMP in a manner that appears random, but is not completely random in what it may contain in some areas of location, etc., in which the distribution of CMP can occur according to a recognizable scheme. For example, CMP can be sprayed onto the paper substrate (eg using an oscillating jet), wherein the CMP is applied in an intermittent spray (and at a reduced rate) such that the CMP is distributed in portions of the paper substrate in a recognizable pattern.

[0023] For the purposes of the present invention, the term "spectral interference" refers to those cases where any of the radiation absorption spectra and / or emission spectra of two or more phosphors are not completely separated (for example, there is an overlap of the absorption or emission spectra), and then has place interference between these phosphors due to the absorption or emission of radiation at a certain wavelength or in a certain range of wavelengths. In other words, when spectral interference occurs, fluorescent materials compete for one wavelength or one range of wavelengths of radiation.

[0024] For the purposes of the present invention, the term "document" (interchangeably referred to as "cards" or "documentation") refers to an article containing one or more paper substrates, the paper substrate(s) containing the CMP and information printed on it, which can be used for purposes of identification, communication of information (eg data), registration of information (eg data), etc. Documents may include, for example, passports, driver's licenses, network access cards, staff badges, visas, immigration documentation, government identification cards, citizenship documents, social security cards, electronic badges, certificates, identification cards, voter registration cards, police officers ID cards, border crossing IDs, legal documents (e.g. contracts, wills, powers of attorney, etc.), badges and badges for security clearance, weapons permits, gift vouchers or cards, product labels or packaging, membership cards or icons, etc.

[0025] For the purposes of the present invention, the term "genuine" refers to the fact that the document is true, real, valid, bona fide, original, etc.

[0026] For the purposes of the present invention, the term "forgery" refers to the fact that the document is false, copy, fake, imitation, counterfeit, etc.

[0027] For the purposes of the present invention, the term "papermaking fibers" refers to any fibrous material that can be used in the manufacture of a fibrous paper web. Papermaking fibers may include cellulose (wood) fibers (e.g., hardwood and/or softwood fibers), kraft pulp fibers (e.g., cellulose fibers obtained by the kraft pulping process), and wood fibers obtained by the soda pulping process. , sulfite, magnetite, cold alkaline, NSSC, etc. pulping processes, synthetic fibers, fibers obtained from recycled paper, fibers from recycled paper, fibers from any of hemp, jute, ramie, flax, cotton linters, abaca, wood waste, straw, bagasse, bamboo, sisal, synthetic {e.g. bicomponent) fibers, etc., as well as any combination of these fibers.

[0028] For the purposes of the present invention, the term "softwood fibers" refers to fibrous pulps obtained from the woody substance of coniferous trees (gymnosperms), such as varieties of fir, spruce, pine, etc., for example, to provide softwood fibers wood species, you can use frankincense pine, swamp pine, prickly spruce, balsam fir, Douglas fir, Banks pine, radiant pine, white spruce, lodgepole pine, mahogany, etc., soft southern and soft northern North American woods, and also soft wood from other regions of the world. The inclusion of softwood fibers helps to give paper substrates greater bending stiffness and a rougher and less smooth surface to paper substrates such as kraft fiber-containing substrates.

[0029] For the purposes of the present invention, the term "hardwood fibers" refers to fibrous pulps derived from the woody substance of deciduous trees (angiosperms) such as birch, oak, beech, maple, eucalyptus, poplar, etc. The inclusion of hardwood fibers in the paper substrates helps to give the paper substrates a smoother surface.

[0030] For the purposes of the present invention, the term "bleached fibers" refers to fibers for papermaking that have been subjected to a bleaching process, for example, to increase brightness, whiteness, etc. paper base obtained from such fibers.

[0031] For the purposes of the present invention, the term "specific volume" refers to the volume or thickness of papermaking fibers relative to their weight. Specific volume is the reciprocal of density (weight per unit volume) and can be calculated from the thickness of the sheet and the basis weight of the paper base containing papermaking fibers. For example, decreasing the specific volume (or, in other words, increasing the density) of a paper base sheet results in the sheet being smoother, glossier, less matte, darker, less durable, and so on. Specific volume is measured by the TAPPI T-220 method and is reported in units of cm ³ /g.

[0032] For the purposes of the present invention, the term "optical brightener (OWA)" refers to certain fluorescent materials that can enhance the brightness (e.g., white appearance) of paper substrate surfaces by absorbing in the non-visible portion of the radiation spectrum (e.g., from about 340 nm to about 370 nm) and converting its energy into the longer wavelength visible part of the radiation spectrum (for example, from about 420 nm to about 470 nm). In other words, OVA converts invisible ultraviolet radiation and re-radiates this converted radiation by fluorescence in the blue-violet region of radiation. OBAs may also be referred to interchangeably as fluorescent whiteners (FWA) and fluorescent whiteners (FBA). These OBAs may include one or more of: 4,4-bis-(triazinylamino)-stilbene-2,2'-disulfonic acids, 4,4'-bis-(triazol-2-yl)stilbene-2,2'- disulfonic acids, 4,4'-dibenzofuranylbiphenyls, 4,4'-(diphenyl)-stilbenes, 4,4'-distyrylbiphenyls, 4-phenyl-4'-benzoxazolylstilbenes, stilbenylnaphthotriazoles, 4-styrylstilbenes, bis-(benzoxazole-2- yl) derivatives, bis-(benzimidazol-2-yl) derivatives, coumarins, pyrazolines, naphthalimides, triazinylpyrenes, 2-styryl-benzoxazole or -naphthoxazoles, benzimidazole-benzofurans or oxanilides, etc. See same-grant U.S. Patent No. 7,381,300 (Skaggs et al.), issued June 3, 2008, the entire content and disclosure of which is incorporated herein by reference. In particular, these OBAs may include, for example, one or more stilbene-based sulfonates (eg, disulfonates, tetrasulfonates, or hexasulfonates), which may contain one or two stilbene residues. Illustrative examples of such anionic stilbene-based sulfonates may include 1,3,5-triazinyl derivatives of 4,4'-diaminostilbene-2,2'-disulfonic acid (including its salts) and in particular bistriazinyl derivatives (e.g. 4,4-bis (triazin-2-ylamino)stilbene-2,2'-disulfonic acid), distyrylbiphenyldisulfonic acid disodium salt, 4,4'-di-triazinylamino-2,2'-di-sulfostilbene disodium salt, etc. Commercially available stilbene-based disulfonate, tetrasulfonate and hexasulfonate OVAs are also available from, for example, Ciba Geigy under the TINOPAL® trade name, Clariant under the LEUCOPHOR® trade name, Lanxess under the BLANKOPHOR® trade name, and 3V under the OPTIBLANC® trade name. . OVA can be used in embodiments of the method of the present invention in amounts of, for example, from about 0.2 wt.% to about 2 wt.% in terms of bleachable cellulose fibers, such as from about 0.4 wt.% to about 0.6 wt.% in terms of bleachable cellulose fibers.

[0033] For the purposes of the present invention, the term "unrefined fibers" refers to cellulosic fibers that have not been refined, i. have not been subjected to a mechanical process, such as milling, to grow or modify the cellulose fibers, often to increase fiber bond strength and/or improve surface properties. For a general description of the refining of cellulose fibers, see G.A. Smook, Handbook for Pulp and Paper Technologists (2nd edition, 1992), pp. 191-202, the entire contents and disclosure of which are incorporated herein by reference.

[0034] For the purposes of the present invention, the term "CTMP fibers" refers to chemical-thermomechanical cellulose (CTMP) fibers that have been subjected to a combination of chemical, thermal and mechanical processing. For the purposes of this document, the term “CTMP fibers” refers to fibers that have been subjected to chemical, thermal, and mechanical treatments in any order of such treatments, including chemical-thermomechanical (C-T-M) cellulose fibers, thermo-chemi-mechanical (T -C-M) pulp, thermomechanochemical (T-M-P) pulp fibers, long-fibre chemical-mechanical pulp/chemically treated long-fiber pulp (LFCMP/CTLF), etc. For a general description of the production of chemical-thermomechanical cellulose (CTMP) for the production of CTMP fibers, see G.A. Smook, Handbook for Pulp and Paper Technologists (2nd edition, 1992), pp. 60-65, the entire contents and disclosure of which are incorporated herein by reference.

[0035] For purposes of the present invention, the term "bleached CMTP fibers" (also interchangeably referred to as "BCMTP fibers") refers to bleached CTMP fibers that have been subjected to one or more bleaching treatments, bleached chemothermomechanical pulp fibers (BCTMP), neutral sulfite semi-chemical cellulose fibers (NSSC), alkali peroxide mechanical cellulose fibers (APMP/AAP), etc.

[0036] For the purposes of the present invention, the term "paper base" refers to a fibrous paper web that can be formed, created, obtained, etc. from a mixture, a fibrous material, etc., containing fibers for making paper, a sizing agent in the mass, etc. with the addition of any other optional papermaking additives such as, for example, paper fillers, wet strength agents, optical brighteners, etc. The paper base may be in the form of a continuous roll, a single sheet, etc.

[0037] For the purposes of the present invention, the term "sheet paper base" refers to a single sheet of paper base.

[0038] For the purposes of the present invention, the term "ream" refers to the generally accepted meaning of this term as providing for a number of printable sheet paper substrates (for example, a packaged amount of printable sheet paper substrates), for example, in the range from about 480 to about 516 sheets (for example 480, 500 or 516 sheets).

[0039] For the purposes of the present invention, the term "printable paper substrate" refers to any paper substrate that can be printed with a printer ink. Printable paper substrates may include webs, sheets, strips, etc., may be in the form of a continuous roll, a single sheet, etc.

[0040] For the purposes of the present invention, the term "synthetic fibers" refers to fibers other than wood pulp fibers (e.g., other than cellulose fibers), which can be made from, for example, cellulose acetate, acrylic, polyamides (such as, for example, nylon, etc.), polyacrylic acid derivatives (such as, for example, polyacrylamide, polyacrylonitrile, esters of methacrylic acid and acrylic acid, etc.), polyolefins (such as, for example, polyethylene, polypropylene, etc. .), polydienes (such as, for example, polybutadiene, polyisoprene, polynorbormene, etc.), polyepoxides, polyesters, polyethers (such as, for example, polyethylene glycol (polyethylene oxide)), polybutylene glycol, polypropylene oxide, polyfluorocarbons, etc. .

[0041] For the purposes of the present invention, the term "bicomponent fibers" refers to synthetic fibers containing a core and sheath configuration. The core and sheath portions of these bicomponent fibers can be made from various polymers. For example, bicomponent fibers may contain a sheath of PE (polyethylene) or modified PE, which may contain a core of PET (polyethylene terephthalate) or PP (polypropylene).

[0042] For the purposes of the present invention, the term "basis weight" refers to the grams of fibers from wood pulp, fibrous web, etc. in a paper base as determined by the TAPPI T410 test. For a description of the physical test to measure the basis weight, see GA Smook, Handbook for Pulp and Paper Technologists (2nd Edition, 1992), pp. 342, Table 22-11, the full contents and disclosure of which are incorporated herein by reference. The basis weight values used herein are measured in grams per square meter (g/m ² ), however they can also be converted to the corresponding basis weight values in terms of pounds/1300 square meters. ft or lbs/3000 sq. ft. For example, a basis weight of 75 g/m ² corresponds to a basis weight of approximately 20 lb/1300 sq. ft or approximately 46.1 lbs/3000 sq. ft.

[0043] For the purposes of the present invention, the term "base pigments" refers to mineral pigments (e.g., calcium carbonate, clay (e.g., kaolin clay), talc, etc.) as well as non-mineral materials (e.g., plastic pigments, etc. ), which can be used in the manufacture of paper in order to reduce the cost of materials per unit mass of the paper base, increase haze, increase smoothness, etc. The mineral pigments may be finely divided, for example in the size range from about 0.5 microns to about 5 microns, may be lamellar mineral pigments, and so on.

[0044] For the purposes of the present invention, the term "calcium carbonate" refers to various types of calcium carbonate that can be used as base pigments, such as precipitated calcium carbonate (PCC), finely divided calcium carbonate (GCC), modified PCC and/or GCC, and etc.

[0045] For the purposes of the present invention, the term "precipitated calcium carbonate (PCC)" refers to calcium carbonate that can be produced by a precipitation reaction and that can be used as a pigment (paper) base. The PCC may almost entirely consist of the calcite crystalline form of CaCO ₃ . Depending on the production conditions, a calcite crystal can have several different macroscopic forms. Precipitated calcium carbonates can be obtained by carbonization with gaseous carbon dioxide (CO ₂ ) of an aqueous suspension of calcium hydroxide ("milk of lime"). The PCC feedstock may be limestone, but may also be calcined (ie, heated to strip CO ₂ ) resulting in quicklime, CaO. Water can be added to "slake" the lime, and the resulting "milk of lime", a suspension of Ca(OH) ₂ , is exposed to bubbles of CO ₂ gas. Low temperatures during the addition of CO ₂ contribute to the production of rhombohedral (block) PCC particles. Higher temperatures during the addition of CO ₂ contribute to the formation of scalenohedral (rosette-shaped) PCC particles. In any case, the end of the reaction occurs at the optimum pH, at which the milk of lime has already been effectively converted to CaCO ₃ and before the concentration of CO ₂ becomes high enough to acidify the slurry, causing some of it to dissolve. In cases where the PCC is not subjected to continuous mixing or aged for many days, the addition of more than a trace amount of anionic dispersants such as polyphosphates may be required. Wet PCC may have a weak positive colloidal charge. In comparison, dried PCC may be similar to most fine CaCO ₃ products in that it has a negative charge, depending on whether dispersants have been used. Calcium carbonate can be precipitated from aqueous solution in three different crystalline forms: the vaterite form, which is thermodynamically unstable, the calcite form, which is the most stable and most abundant in nature, and the aragonite form, which is metastable under normal ambient conditions of temperature and pressure. but can transform into calcite at elevated temperatures. The aragonite form is orthorhombic in shape, which crystallizes as long, thin needles that may be either aggregated or non-aggregated. The form of calcite can exist in several different forms, among which the most common is the rhombohedral form, the crystals of which may be aggregated or non-aggregated, and the scalenohedral form, the crystals of which are usually non-aggregated.

[0046] For the purposes of the present invention, the term "surface sizing composition" refers to those compositions (e.g., size press compositions) that may contain, for example, surface sizing agents, base pigments, polyvalent and/or monovalent metal salt desiccants , cationic dye fixatives, OBAs, solvents, thinners, scratch and scratch resistant agents, CMPs, etc. The surface sizing composition may be in the form of an aqueous solution, an aqueous suspension, a colloidal suspension, a liquid mixture, a thixotropic mixture, and the like.

[0047] For the purposes of the present invention, the term "bulk sizing" refers to the sizing present in the paper base due to incorporation, addition, etc. materials for sizing paper in the mass during the papermaking process before the formation of a fibrous paper base. Stock paper sizing agents generally prevent water or other liquids from penetrating the paper substrate by reacting with the paper substrate to make the paper substrate more hydrophobic. Exemplary stock sizing agents may contain, for example, alkyl ketene dimers, alkenyl succinic anhydrides, and the like.

[0048] For the purposes of the present invention, the term "surface sizing" refers to sizing agents that are applied to, adhered to, etc. surface(s) of the paper base. Surface sizing agents typically prevent water or other liquids from penetrating the paper substrate by coating the paper substrate with a more hydrophobic film. Exemplary surface sizing agents may include, for example, starch, modified starch, styrene-maleic anhydride copolymers, styrene acrylates, polyvinyl alcohol (PVOH), and the like.

[0049] For the purposes of the present invention, the term "surface sizing starch" refers to paper substrate surface sizing agents that include one or more naturally occurring starches (i.e., unmodified starches derived from plant sources such as corn, wheat, rice , potato, tapioca, etc.), such as cereal starches (e.g. corn starch, wheat starch, rice starch, potato starch, oat starch, rye starch, barley starch, sorghum and millet starch, etc.) and non-cereal starches (eg tapioca starch, etc.), modified natural starches (eg ethylated starches, oxidized starches such as oxidized corn starch, etc.), or combinations thereof. Modified starches (e.g. oxidized starches such as oxidized corn starch) can be obtained by one or more of the chemical treatments known in the art of paper sizing starches, for example by oxidation to convert some of the -CH ₂ OH groups to -COOH groups, etc. .d. In some cases, modified starch may contain a small proportion of acetyl groups. Alternatively, the starch may be chemically modified to be cationic (i.e., cationic starch) or amphoteric (i.e., amphoteric starch), i. containing both positive and negative charges. Modified starches may also contain starches converted to starch ether or hydroxyalkylated starch by replacing some _{of the -OH} groups, _e.g. e. ethylated starch), -OCH ₂ CH ₂ CH ₂ OH groups (i.e. propyl starch), etc.

[0050] For the purposes of the present invention, the term "multivalent metal drying salt" refers to those metal drying salts in which the cationic moiety has a positive charge of two or more (e.g., calcium cation, magnesium cation, aluminum cation, etc.), such as calcium salts, magnesium salts, aluminum salts, etc., and which are soluble in water. Counter anions for these polyvalent metal desiccant salts may include, for example, chloride, bromide, acetate, bicarbonate, sulfate, sulfite, nitrate, hydroxide, silicate, hydrochloride, etc. Suitable polyvalent metal drying salts (e.g., divalent metal salts, trivalent metal salts, etc.) may include one or more of calcium chloride, calcium acetate, calcium hydroxide, calcium nitrate, calcium sulfate, calcium sulfite, magnesium chloride, magnesium acetate, magnesium nitrate, magnesium sulfate, magnesium sulfite, aluminum chloride, aluminum nitrate, aluminum sulfate, aluminum hydrochloride, sodium aluminum sulfate, vanadium chloride, etc.

[0051] For purposes of the present invention, the term "monovalent metal salt desiccant" refers to those desiccant metal salts in which the cationic moiety is a monovalent cation that has a positive charge of one (e.g., sodium cation, potassium cation, lithium cation, and etc.), such as sodium salts, potassium salts, lithium salts, etc. Suitable monovalent metal drying salts may include one or more of: sodium chloride, sodium acetate, sodium carbonate, sodium bicarbonate, sodium hydroxide, sodium silicates, sodium sulfate, sodium sulfite, sodium nitrate, sodium bromide, potassium chloride, potassium acetate, potassium carbonate , potassium bicarbonate, potassium hydroxide, potassium silicates, potassium sulfate, potassium sulfite, potassium nitrate, potassium bromide, lithium chloride, lithium acetate, lithium carbonate, lithium bicarbonate, lithium hydroxide, lithium silicates, lithium sulfate, lithium sulfite, lithium nitrate, bromide lithium, etc.

[0052] For the purposes of the present invention, the term "drying time" refers to the time it takes for ink to dry when deposited on the surface of a printable substrate. If the deposited ink does not dry quickly enough, the deposited ink may transfer to other printable sheet substrates, which is undesirable. As a criterion for drying time, the percentage of ink transferred (“IT%”) is recorded. The higher the percentage of transferred paint, the longer (worse) the drying time. Conversely, the smaller the percentage of transferred paint, the shorter (better) the drying time. Typically, embodiments of the printable substrates of the present invention provide an ink transferred percentage ("IT%") value of less than or equal to about 65%. In some embodiments of the printable substrates of the present invention, the IT% value may be less than or equal to about 50%, such as less than or equal to 40% (eg, less than or equal to 30%).

[0053] For the purposes of the present invention, the term "converted to solids" refers to the weight percentage of each present, etc. appropriate solid materials (eg paper pulp fibers, etc.) in the absence of any liquids (eg water). Unless otherwise noted, all percentages in this document are for solids on a solids basis.

[0054] For the purposes of the present invention, the term "solids content" refers to the percentage of non-volatile, non-liquid components (by weight) that are present in the composition, etc.

[0055] For purposes of the present invention, the term "calcium carbonate" refers to various calcium carbonates that can be used as fillers for paper, such as precipitated calcium carbonate (PCC), finely divided calcium carbonate (GCC), modified PCC and/or GCC, and etc.

[0056] For the purposes of the present invention, the term "precipitated calcium carbonate (PCC)" refers to calcium carbonate that can be produced by a precipitation reaction and that can be used as a filler for paper. The PCC may almost entirely consist of the calcite crystalline form of CaCO ₃ . Depending on the production conditions, a calcite crystal can have several different macroscopic forms. Precipitated calcium carbonates can be obtained by carbonization with gaseous carbon dioxide (CO ₂ ) of an aqueous suspension of calcium hydroxide ("milk of lime"). The PCC feedstock may be limestone, but may also be calcined (ie, heated to strip CO ₂ ) resulting in quicklime, CaO. Water can be added to "slake" the lime, and the resulting "milk of lime", a suspension of Ca(OH) ₂ , is exposed to bubbles of CO ₂ gas. Low temperatures during the addition of CO ₂ contribute to the production of rhombohedral (block) PCC particles. Higher temperatures during the addition of CO ₂ contribute to the formation of scalenohedral (rosette-shaped) PCC particles. In any case, the end of the reaction occurs at the optimum pH, at which the milk of lime has already been effectively converted to CaCO ₃ and before the concentration of CO ₂ becomes high enough to acidify the slurry, causing some of it to dissolve. In cases where the PCC is not subjected to continuous mixing or aged for many days, the addition of more than a trace amount of anionic dispersants such as polyphosphates may be required. Wet PCC may have a weak positive colloidal charge. In comparison, dried PCC may be similar to most fine CaCO ₃ products in that it has a negative charge, depending on whether dispersants have been used. Calcium carbonate can be precipitated from aqueous solution in three different crystalline forms: the vaterite form, which is thermodynamically unstable, the calcite form, which is the most stable and most abundant in nature, and the aragonite form, which is metastable under normal ambient conditions of temperature and pressure. but can transform into calcite at elevated temperatures. The aragonite form is orthorhombic in shape, which crystallizes as long, thin needles that may be either aggregated or non-aggregated. The form of calcite can exist in several different forms, among which the most common is the rhombohedral form, the crystals of which may be aggregated or non-aggregated, and the scalenohedral form, the crystals of which are usually non-aggregated.

[0057] For the purposes of the present invention, the term "brightness" refers to the diffuse reflectance of the paper, for example at an average wavelength of 457 nm. Within the scope of this document, the luminance of a paper substrate can be measured in terms of ISO luminance, where luminance is measured using, for example, an ELREPHO Datacolor 450 spectrophotometer according to ISO 2470-1 test method using a Type C light source with UV inclusion.

[0058] For the purpose of the present invention, the term "printing device" refers to any device that prints an image on a printable substrate, such as a sheet of paper, including laser printers, inkjet printers, electrophotographic recording devices (e.g. copiers), scanning devices, fax machines, etc.

[0059] For the purpose of the present invention, the term "printer pigment" can refer to either an ink (used in, for example, an ink jet printer, etc.) or a toner (used, for example, in a laser printer, electrophotographic recorder, and etc.).

[0060] For the purpose of the present invention, the term "ink" refers to a printer pigment used in inkjet printers. The term "paint" may include dye-based paints and/or pigment-based paints. Dye-based paints contain a dye, which may be organic molecules that are soluble in the paint medium. Dye-based paints can be classified by their use, such as acid dyes, basic dyes or direct dyes, or by their chemical structure, such as azo dyes, which are based on the structure of the -N=N- azo group; diazonium dyes based on diazonium salts; quinone imine dyes derived from quinine, etc. Pigment-based paints contain pigment, which is solid colored particles suspended in a paint medium. The particles may contain a colored mineral, a precipitated dye, a precipitated dye attached to a carrier particle, and so on. Paints are often spread, deposited, sprayed, etc. onto a printable medium in the form of droplets, which are then dried on the printable medium to form the printed image(s).

[0061] For the purpose of the present invention, the term "toner" refers to a printing pigment (containing a toner resin) used in laser printers. Toner often spreads, deposits, etc. onto a printable particulate carrier which is then thermally fixed onto a printable carrier to form an image.

[0062] For the purposes of the present invention, the term "flooded gap size press" refers to a size press containing a flooded gap (reservoir) and also referred to as a "tub size press". Flooded gap size presses can include vertical size presses, horizontal size presses, etc.

[0063] For the purposes of the present invention, the term "dosing size press" refers to a size press containing a component for distribution, dosing, etc. compositions for sizing the surface, deposited, applied, etc. on the side or surface of the paper base. The metering size presses may include a metering rod size press, a metering gate roller size press, a knife metering size press, and the like.

[0064] For the purposes of the present invention, the term "dosing stick size press" refers to a dosing size press in which for distribution, dosing, etc. composition for sizing the surface on the surface of the paper base uses a rod. The rod may be fixed or movable relative to the paper base.

[0065] For the purposes of the present invention, the term "gate-roll size-dispensing press" refers to a size-dispensing press that can use a gate roll, a feed roll, a soft knurl, etc. Gate Roll, Print Roll, Soft Roll, etc. may be fixed relative to the paper substrate, may rotate relative to the paper substrate, etc.

[0066] For the purposes of the present invention, the term "room temperature" refers to the generally accepted meaning of room temperature, i.e. to an ambient temperature of 20-25°C.

[0067] For the purposes of the present invention, the term "comprising" means that various compounds, components, polymers, ingredients, substances, materials, layers, steps, etc. can be used together in embodiments of the present invention. Accordingly, the term "comprising" encompasses the more restrictive terms "consisting essentially of" and "consisting of".

[0068] For the purposes of the present invention, the term "and/or" means that one or more of various compositions, compounds, polymers, ingredients, components, elements, functionality, layers, steps, etc. can be used in embodiments of the present invention. .

Description

[0069] For SMR pigment compositions, infrared (IR) absorbing inks and infrared (IR) sensors can be used to track and authenticate a variety of document types, including, for example, labels, barcodes, other identifiable markings. formed by these IR-absorbing inks on the surface of such documents, etc. Such documents, once marked, can then be illuminated with IR and examined with an infrared sensor to authenticate or trace the document. Even under these conditions, prior art IR dyes used in such inks may have a visible color associated with them, resulting in visible coloring of the resulting dye-based IR inks and printed matter. Additionally, prior art dye-based IR inks generally have the disadvantage of limited solubility in the ink base, as well as low lightfastness and environmental resistance (eg resistance to air, water, moisture, temperature, etc.). In addition, conventional pigmented IR absorbing paints may contain carbon black as an IR absorbing material, resulting in a dark paint with high visibility. The problems associated with this visibility and potential discoloration make it problematic to use these prior art dye-based IR inks in conjunction with, for example, white-dyed paper substrates.

[0070] Anti-Stokes shifted infrared (IR) pigments can be used as the latent marking (CMP) pigment in these CMP compositions to avoid such visible staining on paper substrates dyed white. However, in order to incorporate such CMPs in order to be compatible with the binder used in the pigment dispersing CMP composition, extremely fine grinding of the pigment with an anti-Stokes shift in the IR spectrum may be required. This grinding of these pigments can significantly increase the cost per kilogram of such used CMP compositions. Alternatively, these IR anti-Stokes shifted pigments may require surface treatment to be compatible with the ink binder so that the binder can wet and hold the pigment particles, which also increases the cost of the CMP composition. For printing on paper substrates, such CMP compositions containing these IR anti-Stokes pigments may require many additional chemical components (e.g. viscosity modifiers, dispersants, solvents, binders, etc.) to ensure printing of CMP compositions, their drying and retention of anti-Stokes shift pigments in the IR spectrum after drying, all of which also increase the cost of using such CMP compositions.

[0071] Additionally, when printing such a CMP composition on a paper base, the anti-Stokes shifted pigment in the IR spectrum may require printing at a specific location or location on the paper base. This also means that a sensor for an IR anti-Stokes pigment may need to be told where to look for that pigment. This may in particular be the case when printing a CMP composition on a paper base in order to enable the authenticity of a document such as, for example, banknotes, clothing tags, tickets, badges, etc.

[0072] In response to these problems with visibility, cost, etc. in embodiments according to the present invention, there are provided products in the form of paper substrates with a latent mark, which contain a paper base and a pigment for latent marking (hereinafter referred to as "CMP"). CMP is characterized by a particle size ranging from about 0.1 micron to about 5 micron. This range includes all values and subranges in between, including 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0 , 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.1, 2.2, 2 .3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3.0, 3.1, 3.2, 3.3, 3.4, 3.5 , 3.6, 3.7, 3.8, 3.9, 4.0, 4.1, 4.2, 4.3, 4.4, 4.5, 4.6, 4.7, 4 .8, 4.9 and 5.0 microns. CMP is incorporated into the paper base in an IR detectable amount ranging from about 0.1 mg/m ² to 1000 mg/m ² (eg, 2 mg/m ² to 10 mg/m ² ). This range includes all values and subranges in between, including 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0 , 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.1, 2.2, 2 .3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3.0, 3.1, 3.2, 3.3, 3.4, 3.5 , 3.6, 3.7, 3.8, 3.9, 4.0, 4.1, 4.2, 4.3, 4.4, 4.5, 4.6, 4.7, 4 .8, 4.9, 5.0, 5.1, 5.2, 5.3, 5.4, 5.5, 5.6, 5.7, 5.8, 5.9, 6.0 , 6.1, 6.2, 6.3, 6.4, 6.5, 6.6, 6.7, 6.8, 6.9, 7.0, 7.1, 7.2, 7 .3, 7.4, 7.5, 7.6, 7.7, 7.8, 7.9, 8.0, 8.1, 8.2, 8.3, 8.4, 8.5 , 8.6, 8.7, 8.8, 8.9, 9.0, 9.1, 9.2, 9.3, 9.4, 9.5, 9.6, 9.7, 9 .8, 9.9, 10, 50, 100, 150, 200, 250, 300, 350, 400, 450, 500, 550, 600, 650, 700, 750, 800, 850, 900, 950 and 1000 mg / m ² . The CMP may be one or more IR anti-Stokes shift pigments selected from one or more of: yttrium oxide; double sodium-yttrium fluoride; lanthanum oxide; lanthanum fluoride; yttrium oxysulfide; lanthanum oxysulfide; gadolinium (Gd2O2S); ytterbium (Yb) or mixtures thereof.

[0073] Embodiments of the present invention also relate to a method of manufacturing these paper bases with hidden markings. The method includes the step of providing a composition containing a CMP having a particle size ranging from about 0.1 micron to about 5 micron, wherein the CMP is one or more IR anti-Stokes shift pigments selected from one or more of: oxide yttrium; double sodium-yttrium fluoride; lanthanum oxide; lanthanum fluoride; yttrium oxysulfide; lanthanum oxysulfide; gadolinium (Gd2O2S); ytterbium (Yb) or mixtures thereof. The method also includes the step of incorporating the composition according to step (a) using a non-printing solution into the paper base in an amount detectable in the IR range, in the range from about 0.1 mg/m ² to 1000 mg/m ² ( eg 2 mg/m ² to 10 mg/m ² ). This range includes all values and subranges in between, including 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0 , 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.1, 2.2, 2 .3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3.0, 3.1, 3.2, 3.3, 3.4, 3.5 , 3.6, 3.7, 3.8, 3.9, 4.0, 4.1, 4.2, 4.3, 4.4, 4.5, 4.6, 4.7, 4 .8, 4.9, 5.0, 5.1, 5.2, 5.3, 5.4, 5.5, 5.6, 5.7, 5.8, 5.9, 6.0 , 6.1, 6.2, 6.3, 6.4, 6.5, 6.6, 6.7, 6.8, 6.9, 7.0, 7.1, 7.2, 7 .3, 7.4, 7.5, 7.6, 7.7, 7.8, 7.9, 8.0, 8.1, 8.2, 8.3, 8.4, 8.5 , 8.6, 8.7, 8.8, 8.9, 9.0, 9.1, 9.2, 9.3, 9.4, 9.5, 9.6, 9.7, 9 .8, 9.9, 10, 50, 100, 150, 200, 250, 300, 350, 400, 450, 500, 550, 600, 650, 700, 750, 800, 850, 900, 950 and 1000 mg / m ² .

[0074] Embodiments of the present invention further relate to a method for controlling the amount of printer pigment deposited on a sheet paper base by providing a sheet paper base with latent marking, which contains: a sheet paper base; and CMP having a particle size in the range of about 0.1 micron to about 5 micron and incorporated into the base paper sheet in an IR detectable amount in the range of about 0.1 mg/m ² to 1000 mg/m ² (for example, from about 2 mg/m ² to 10 mg/m ² ), and a method identifying the type of sheet paper base with a hidden mark, while the pigment for the hidden mark is one or more anti-Stokes shift pigments selected from one or more from: yttrium oxide; double sodium-yttrium fluoride; lanthanum oxide; lanthanum fluoride; yttrium oxysulfide; lanthanum oxysulfide; gadolinium (Gd2O2S); ytterbium (Yb) or mixtures thereof. These ranges include all values and subranges in between, including, respectively, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.1, 2, 2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3.0, 3.1, 3.2, 3.3, 3.4, 3.5, 3.6, 3.7, 3.8, 3.9, 4.0, 4.1, 4.2, 4.3, 4.4, 4.5, 4.6, 4, 7, 4.8, 4.9 and 5.0 microns and 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9 , 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.1, 2 .2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3.0, 3.1, 3.2, 3.3, 3.4 , 3.5, 3.6, 3.7, 3.8, 3.9, 4.0, 4.1, 4.2, 4.3, 4.4, 4.5, 4.6, 4 .7, 4.8, 4.9, 5.0, 5.1, 5.2, 5.3, 5.4, 5.5, 5.6, 5.7, 5.8, 5.9 , 6.0, 6.1, 6.2, 6.3, 6.4, 6.5, 6.6, 6.7, 6.8, 6.9, 7.0, 7.1, 7 .2, 7.3, 7.4, 7.5, 7.6, 7.7, 7.8, 7.9, 8.0, 8.1, 8.2, 8.3, 8.4 , 8.5, 8.6, 8.7, 8.8, 8.9, 9.0, 9.1, 9.2, 9.3, 9.4, 9.5, 9.6, 9 .7, 9.8, 9.9, 10, 50, 100, 150, 200, 250, 300, 350, 400, 450, 500, 550, 600, 650, 700, 750, 800, 850, 900, 950 and 1000 mg/m ² . In this method, the labeled paper base sheet is scanned with an IR pigment sensor to identify the type of the labeled paper base sheet. The amount of printer pigment deposited on the latent mark paper base sheet is adjusted in response to the type of latent mark paper base sheet identified by the IR pigment sensor.

[0075] Embodiments of the present invention further relate to a method for determining whether a paper base sheet is a genuine document. In this method, the base paper sheet is also scanned with an IR pigment sensor, but to detect if there is an introduction to the base paper sheet of a certain CMP, the CMP being one or more anti-Stokes shifted pigments in the IR spectrum selected from one or more of: yttrium oxide; double sodium-yttrium fluoride; lanthanum oxide; lanthanum fluoride; yttrium oxysulfide; lanthanum oxysulfide; gadolinium (Gd2O2S); ytterbium (Yb) or mixtures thereof. If the pigment IR sensor detects that the base paper sheet contains a certain CMP, the base paper sheet is identified as genuine. Conversely, if the IR pigment sensor detects that the base paper sheet does not contain a certain CMP, the base paper sheet is identified as counterfeit.

[0076] Embodiments of the labeled sheet substrate (including sheets or stacks of such labeled paper substrates) according to the present invention thus comprise CMP, which is invisible to the naked eye under white light illumination conditions. Therefore, copiers, printers, multifunction copiers/printers/scanners/fax machines, etc. can be equipped with IR sensors to identify the type of sheet paper base containing the latent marking pigment, and thus it can be possible to adjust (eg reduce) the amount of toner or ink needed to obtain a suitable image. Embodiments of the hidden label paper base sheet of the present invention that contains CMP can also be used to determine whether the base paper sheet is a genuine or counterfeit document. Additionally, by incorporating CMP into the paper substrate other than by a technical solution involving printing, for example by applying the CMP composition on a size press or spraying it onto a sheet paper substrate, CMP with larger particles can be used. Such large CMP particle sizes can reduce the cost of CMP compositions, including reducing the cost of how much surface area of the substrate needs to be treated with CMP so that it can be detected by an IR sensor. In some embodiments, the implementation of the CMP, if compatible, can be entered as a component of the composition for the size press. In some embodiments, the implementation of CMP can be entered by: spraying CMP on a paper base; introducing CMP into the papermaking fibrous material in the wet end of the paper machine; coating the CMP composition by pouring; introducing CMP into the fibrous papermaking material in the headbox; introducing CMP into the fibrous papermaking material at other compression points; bonding CMP with papermaking fibers in the fibrous papermaking material; etc.

[0077] The CMPs used in such CMP compositions can be chosen to minimize, eliminate, etc. spectral interference with the optical properties of the sheet paper substrate, including such sheets containing, for example, optical brighteners (OVA), other paper pigments, in particular those that impart a white tint, etc. In other words, the paper substrate treated with the CMP compositions can retain the desired optical properties in the visible spectrum as if the CMP composition were not present, ie. CMPs and compositions containing them should be chosen so as not to cause spectral interference with the fluorescence of OBAs, etc., which may be used in such sheet paper substrates. Other factors in selecting suitable CMPs may include adverse effects on the electrostatic properties (resistance, capacitance, etc.) of the paper, which may be required for e.g. toxicologically safe for use in paper substrates, the possibility of adverse effects of CMP on the tone / color / shade of the paper base, thermal stability of CMP, etc.

[0078] In embodiments of the methods of the present invention, CMP may be distributed in a random pattern, a pseudo-random pattern, and so on. Such CMP distribution schemes can make it possible to minimize the amount of CMP introduced per unit surface area of the base paper, i. e. expressed in mg/m ² . The CMP composition can be applied to both outer surfaces of the base paper, but can also be applied to only one outer surface of the paper base. The CMP composition can also be injected under the outer surfaces of the paper base, depending on the penetration strength of the wavelength of radiation that is used in the IR sensor. The possibility of using IR sensors having wavelengths with increased penetration into the CMP-treated sheet also allows smaller amounts of CMP to be introduced into the sheet paper base.

[0079] In some embodiments of the present invention, to control ink or toner consumption, the IR sensor of a printer, copier, multifunction copiers/printers/scanners/fax machines, etc. can be configured to inspect each such sheet paper base and accept and maintain a lower ink or toner consumption for a certain number of such sheet paper bases. For example, in some embodiments, in the form of a stack of sheet paper substrates, only a portion of the sheet paper substrates is treated with the CMP composition. In these embodiments, only some, but not all, of the specified number of sheet paper foot bases are treated with the CMP composition. For example, the sheet paper bases in a stack can be combined such that only a portion (ie, a certain amount) of the sheet paper bases is treated with the CMP composition. For example, in some embodiments, one-third to one-fifth of the sheet paper bases of the foot can be treated with the CMP composition. Such an embodiment would also allow different base paper rolls to be used and combined, whereby, for example, only one of these base paper rolls is treated with the CMP composition. In such a multi-roll embodiment, it is possible to reduce the amount of CMP composition needed and thus further reduce the additional cost introduced by the CMP-treated base paper sheet. In an alternative embodiment, only the edge of the base paper roll can be treated with the CMP composition, for example by spraying the CMP composition onto the edge of the base paper roll. In yet another alternative embodiment, a plurality of sheet paper substrates in the form of, for example, a stack may comprise one end of the sheet paper substrates in the stack treated with the CMP composition. In such an embodiment, the IR sensor of the printer, copier, multifunction copiers/printers/scanners/fax machines, etc. a command may be given to scan the edge of a stack or part of a stack of sheet paper substrates in the tray of a printer, copier, multifunction copiers/printers/scanners/fax machines, etc. in order to determine the type of sheet paper in the tray and adjust the consumption of ink or toner accordingly.

EXAMPLES

Example 1

[0080] Paper not processed in a size press was made. A size press solution was prepared with starch and the following additives: calcium carbonate, sodium chloride and optical brighteners. The starch solids were selected to simulate starch extraction on a paper machine with a target total starch weight gain of 120 pounds per ton. The starch was labeled and applied to the starch on surfaces using a sheet lubricant. Two labels were used with absorption in the IR range and emission in the green region of visible light (G0) and absorption in the IR range and invisible emission (10). Loading of each tag was 25, 50 and 100 ppm based on paper weight with a total starch weight gain target of 120 pounds per ton.

[0081] Conditions. The leaf was weighed before starch application. After starch was applied to the sheet, the wet sheet was then dried and the weight gain of starch was measured. Control sheets were tested without CMP. Different concentrations of CMP were applied to both sides of the sheet in a size press solution. Exemplary sheets were illuminated and the fluorescence response measured at 950 nm. The sheets showed an increase in IR emission as the ppm content of the label increased.

Example 2

The same procedure as in Example 1 was followed, but the CMP starch solution was applied to only one side of the sheet. Only the starch solution was applied to the other side of the sheet.

[0082] All documents, patents, journal articles and other materials cited in this application are incorporated herein by reference.

[0083] While the present invention has been fully described in conjunction with several embodiments thereof with reference to the accompanying drawings, it should be understood that various changes and modifications may be apparent to those skilled in the art. Such changes and modifications are to be understood as being included within the scope of the present invention as defined by the appended claims, unless they go beyond its scope.

Claims (26)

1. The product in the form of a paper base with hidden markings, containing: a paper base; and a latent marking pigment having a particle size in the range of about 0.1 µm to about 5 µm and incorporated into the base paper in an IR detectable amount of from about 2 mg/m ² to about 10 mg/m ² , at In this, the watermark pigment is one or more IR anti-Stokes shift pigments selected from one or more of: yttrium oxide; double sodium-yttrium fluoride; lanthanum oxide; lanthanum fluoride; yttrium oxysulfide; lanthanum oxysulfide; gadolinium (Gd2O2S); ytterbium (Yb) or mixtures thereof. 2. The product according to p. 1, characterized in that the pigments with anti-Stokes shift in the IR spectrum are selected from one or more of: yttrium oxide; double sodium-yttrium fluoride; lanthanum oxide; gadolinium (Gd2O2S) or ytterbium (Yb). 3. An article according to claim 1, characterized in that the latent marking pigment is randomly distributed in the paper base. 4. The product according to claim. 1, characterized in that the paper base contains two outer surfaces, and the pigment for hidden marking is applied to one of the two outer surfaces. 5. The product according to claim. 1, characterized in that the paper base contains two outer surfaces, and the pigment for hidden marking is introduced under these two outer surfaces. 6. The product according to claim. 1, characterized in that it has the form of a pile of sheet paper bases, while at least part of the stack contains sheet paper bases with hidden markings. 7. The product according to claim. 6, characterized in that the sheet paper bases with hidden markings in the foot are from one third to one fifth of the sheet paper bases in the foot. 8. The product according to claim 6, characterized in that the sheet paper bases contain two opposite side edges, and the hidden mark pigment is inserted on one of these side edges of each sheet paper base with a hidden mark in the stack. 9. The product according to claim. 1, characterized in that the paper base contains an optical brightener. 10. A method for producing a paper base with hidden markings, wherein the method includes the following steps: (a) providing a composition comprising a water mark pigment having a particle size ranging from about 0.1 µm to about 5 µm, wherein the water mark pigment is one or more IR anti-Stokes shift pigments selected from one or more of: yttrium oxide; double sodium-yttrium fluoride; lanthanum oxide; lanthanum fluoride; yttrium oxysulfide; lanthanum oxysulfide; gadolinium (Gd2O2S); ytterbium (Yb) or mixtures thereof; and (b) incorporating the composition of step (a) via a non-printing solution into the paper base in an IR detectable amount of about 2 mg/m ² to about 10 mg/m ² . 11. The method according to claim 10, characterized in that the composition according to step (a) contains a size press composition, which additionally contains a sizing agent, and wherein the size press composition is introduced into the paper base in step (b) at the size press . 12. The method according to p. 10, characterized in that the pigments with anti-Stokes shift in the IR spectrum according to step (a) are selected from one or more of: yttrium oxide; double sodium-yttrium fluoride; lanthanum oxide; gadolinium (Gd2O2S) or ytterbium (Yb). 13. Method according to claim 10, characterized in that step (b) is carried out by randomly distributing the latent marking pigment in the paper base. 14. Method according to claim 10, characterized in that the base paper according to step (b) comprises two outer surfaces, and in step (b) the surfactant pigment is applied to one of the two outer surfaces. 15. The method according to claim 10, characterized in that the paper bases according to step (b) are formed into a stack of sheet paper bases, and at the same time from one third to one fifth of the sheet paper bases in this pile are sheet paper bases with hidden markings. 16. The method according to claim 15, wherein the base paper according to step (b) comprises two opposite side edges, and the ink mark pigment is applied to one of these side edges of each sheet of base mark paper in the stack. 17. A method for determining whether a sheet paper base is a genuine document, the method comprising the following steps: (a) providing a sheet paper base; and (b) scanning the sheet paper base with an IR pigment sensor to detect whether a particular latent marking pigment has been incorporated into the sheet paper base in an IR detectable amount of about 2 mg/m ² to about 10 mg/m ² , wherein the smudge pigment is one or more IR anti-Stokes shift pigments selected from one or more of: yttrium oxide; double sodium-yttrium fluoride; lanthanum oxide; lanthanum fluoride; yttrium oxysulfide; lanthanum oxysulfide; gadolinium (Gd2O2S); ytterbium (Yb) or mixtures thereof; however, if the IR pigment sensor detects that the base paper sheet: (i) contains a certain latent marking pigment, then the sheet paper base is identified as genuine; or (ii) does not contain a specified latent marking pigment, then the paper backing sheet is identified as counterfeit. 18. The method of claim. 17, characterized in that each sheet of paper base according to step (a) contains two outer surfaces, and each sheet of paper base, which is a genuine document, contains a certain pigment for latent marking in the sheet of paper base under two outer surfaces. 19. Method according to claim 17, characterized in that the concealed marking pigment is randomly distributed in the sheet paper bases according to step (a). 20. The method according to p. 17, characterized in that the pigments with anti-Stokes shift in the IR spectrum according to step (a) are selected from one or more of: yttrium oxide; double sodium-yttrium fluoride; lanthanum oxide; gadolinium (Gd2O2S) or ytterbium (Yb).