MXPA99010457A - Process to manufacture and detect paper against falsification - Google Patents

Abstract

The present invention relates to a method for producing paper against counterfeiting. Processes of this type generally add a certain percentage of lumens of wood fiber that have been loaded with one or more fluorescent agents. These wood fiber lumens would appear normal under regular light, but will glow when exposed to various types of radiation.

Description

PROCESS TO MANUFACTURE AND DETECT PAPER AGAINST COUNTERFEIT FIELD OF THE INVENTION This invention relates to a method for producing paper against counterfeiting. Processes of this type generally add a certain percentage of lumens of wood fibers that have been loaded with one or more fluorescent agents. These wood fiber lumens would appear normal under regular light but will glow when exposed to various types of radiation.

BACKGROUND OF THE INVENTION Traditionally, counterfeiting has been associated with the illicit production of money. However, today there are significant losses for manufacturers, due to the falsification of computer programs, compact discs, cigarettes, video tapes, etc. This type of counterfeiting costs companies millions of dollars of lost revenue. In addition, these counterfeit items are usually manufactured in a cheap way, thereby causing a naive consumer to question the manufacturer's quality. Undoubtedly, the main interest of a company is to eliminate counterfeit products, from an economic point of view and from the point of view of public perception. Manufacturers have many different options at their disposal to combat counterfeiting. These include the watermark, specialized printing, the use of holographic labels, the use of fibers or synthetic additives, etc. These anti-counterfeiting techniques are described below. The watermark consists of the printing of a design on the continuous belt of wet fiber before application to the paper, of the primer layer. Since this process is done at the beginning of the process, it accommodates some of the fibers found in the paper. This arrangement of the fibers makes the watermark difficult to counterfeit. The watermark is used extensively in money and in security documents, from the United States and Europe. Other inventors have worked to increase the safety of the watermark placement process, by controlled deposition of the fiber during the paper forming process and by placing unique and individual watermarks on each piece of paper. The use of the watermark is ideally suited for thin papers such as money, bank checks, etc., which are translucent.

Unfortunately, the use of watermarks on thick paper and cardboard is less useful due to the low transmission of light. A filigree in these thicker papers would not manifest easily as it does in translucent, thinner papers. Traditionally, complicated printing techniques have also been used in securities and money documents. These typically consist of natural-looking portraits and intricate designs. Additionally, special inks, mixed exclusively for these end uses, have an extensive use in the securities documents sector. These special inks include all those to make use in multiple colors, to use high intensity ultraviolet light and create a fluorescent pattern in visible or ultraviolet light. However, the advent of high-quality color photocopiers has made the use of special ink colors and intricate designs less than a barrier to the counterfeiter. In response to the growing ingenuity of counterfeiters, microprinting has been developed. Microprinting is a technique where messages, etc., are finely printed on a material. At first glance the messages appear as a simple line, but under the amplification, the messages are revealed. This technique makes the falsification of the material more problematic, because the printing technique is difficult to perform. However, the disadvantage of this microprinting technique is that it is relatively easy to acquire a printing press. As well, this printing equipment can be accommodated anywhere and kept well hidden. Holographic labels are also used extensively as a counterfeiting device. These labels have an image printed inside them, which changes depending on the point of observation. A familiar example of these labels is the bright image of credit cards. Although these are effective as a counterfeiting device, they are expensive to produce and it is difficult to keep abreast of them. The placement of stained synthetic fibers, within the printing substrate, has been practiced for many years as a device against counterfeiting. A common example is the paper used for American money that has blue and red synthetic fibers in it. Although effective, it has a significant disadvantage because it can only be used in specific applications. For example, paper money would not be suitable for printing in general, because stained synthetic fibers would be lost in view in the images and / or in the printing.

Also, the related technique contains references to yews, which are tiny discs that appear on paper. The discs are usually made of moisture resistant paper, however plastic is sometimes used. The yew trees can be visible, invisible, sensitive to ultraviolet light, etc. Additionally, yew trees can be formulated to contain a portion of a compound that changes color, which is then incorporated into the paper. When the second portion of the compound that changes color is applied, the yews change colors. Exemplary of that prior art is US Patent No. 4,037,007 issued to W. A. Wood, entitled "Paper for Authentication of Documents". Although yew trees are an effective measure against counterfeiting, they have several disadvantages. The main one is that they can interfere in the printing processes. Many inks used in the printing process are sticky. This stickiness can remove the loose yew, causing poor printing. If this happens, the press should stop to clean the loose yews. Finally, some manufacturers have used fibers dyed with a fluorescent agent. These fibers do not manifest easily under normal light, however, under ultraviolet light these fibers shine. Exemplary of this prior art is US Patent No. 2,379,443, entitled "Process for the Manufacture of Identifiable Paper", issued to Kantrowitz et al., Although US Patent No. 2,379,443 describes a process by which a percentage of fibers is dispersed chemically treated, in the fiber raw material, before the papermaking process, the chemically treated fibers can not be distinguished from normal fibers until the paper is treated with a solution that reacts with the chemically treated fibers, to produce a irreversible color change Although US Patent No. 2,379,443 discloses the use of ultraviolet radiation as a means to cause chemically treated fibers to fluoresce, there are two main differences between US Patent No. 2,379,443 and the present invention. those differences is that the present invention uses a lumen loading technique , which will be described later, to place the fluorescent material or colorant within the fiber. The technique of the present invention also includes rinsing excess fluorescent material from the exterior of the fiber. The lumen loading technique of the present invention is performed to trap or contain the fluorescent materials within the fiber, thereby minimizing the amount of ink migrating from the paper.

Minimizing the migration of these materials is important for certain end uses such as in pharmaceutical and food packaging. The reason is that fluorescent materials usually have some associated toxicity and therefore excess exposure to the consumer should be kept to a minimum. By trapping or containing the fluorescent materials within the fiber, potential migration from the paper to the drug or food being packaged is reduced, thereby reducing exposure to a toxic substance. Even in other end uses where the transfer potential of fluorescent material is low, it is always beneficial to minimize exposure to toxic compounds. Examples of these end uses include securities documents, such as checks, bank notes, etc. The second major difference between U.S. Patent No. 2,379,443 and the present invention is that U.S. Patent No. 2,379,443 discloses only the use of materials that emit fluorescence when exposed to ultraviolet radiation. In contrast, the present invention describes the use of fluorescence emitting materials under all types of radiation, including, but not limited to, ultraviolet and infrared radiation. When using different materials that emit fluorescence under different sources of radiation, the present invention allows multiple methods to verify that an article is genuine. For example, if a paper contains fibers loaded in the lumen, in accordance with the present invention, which emit fluorescence under ultraviolet radiation, and also contains fibers treated in a similar manner, which emit fluorescence under infrared radiation, then it is very likely that the counterfeiter fails to achieve one of the fluorescents and make an imperfect copy. From the foregoing, it is evident that there is a need in the art for a technique against counterfeiting that is not expensive, that is effective and that is difficult to copy. In addition, the technique should not interfere with the substrate's printing characteristics and coating operations. The purpose of this invention is to satisfy this and other needs in the art, in a manner more apparent to one skilled in the art, once the following description is provided.

SUMMARY OF THE INVENTION Generally speaking, this invention meets these needs by providing a method for producing and detecting a counterfeiting paper, which comprises dissolving a soluble, fluorescent ink in a solvent, removing water from wood fibers having lumens, up to a solids content of up to 50% solids, mix the fluorescent ink dissolved with wood fibers that have been removed water, so that the fluorescent agent is loaded into the lumens of the fibers, clean the loaded wood fibers, to remove substantially any excess fluorescent ink that is on the outside of the lumens of the wood fibers, seal the ink substantially within the lumens of the wood fibers, remove the fluorescent ink charged to the fibers of wood, dry loaded wood fibers, add wood fibers loaded in the lumen and clean, to a raw material consisting of in paper pulp, at a ratio of Z2% of the total raw material, where Z2 (ppm) = concentration of the fibers loaded in the lumen, in the raw material = Z, x 907. 2 kq (1 ton) 1,000,000, 907. 2 kg (2000 Ib) where Z, = number of fibers loaded in the lumen, in the raw material, in pounds / ton of fiber, forming from the raw material loaded in the lumen, a paper against counterfeiting, and employing a light source of radiation, to detect the fluorescent ink in the fiber loaded in the lumen. In certain preferred embodiments the water is removed from the wood fibers to a solids content of about 30% solids. Also, charged wood fibers are added to the pulp-based raw material for papermaking, at a ratio of a few parts per billion to 20-25%. In another, preferred embodiment, the introduction of the wood fibers loaded into the lumen into the pulp-based raw material for papermaking produces a counter-counterfeiting role, with fibers that will be recognizable under various types of ultraviolet radiation. In another further preferred embodiment, the light of the radiation will cause the fluorescence to occur in the visible range, ie, be optically active. A preferred method, in accordance with this invention, offers the following advantages: ease of paper production against counterfeiting and excellent economy. Indeed, in many preferred embodiments, these factors of ease of production and excellent economy are optimized to an extent that is considerably greater than that which has been achieved hitherto in the prior known methods.

II DETAILED DESCRIPTION OF THE INVENTION The dyeing of the wood fibers for the present invention is performed "off-line". Examples of such "off-line" dyeing can be found in the commonly assigned US Patent No. 5,759,349. The present invention requires a strong cohesion between the ink and the fibers, in such a way that the ink can not be extracted and / or exude towards the surrounding fibers in the final packaging. The ink should be such that it emits fluorescence under ultraviolet (or "black") light, under infrared light, or under any other appropriate radiation. Similarly, the ink can be any material that is bright or recognizable when exposed to a source of radiation, but can not easily be distinguished under normal conditions. A further embodiment of this invention would be to use several different types of stained wood fibers. The fluorescent ink would be selected in such a way that several different colors would emit fluorescence under ultraviolet, infrared, or other appropriate light source. In the paper industry there is an ink class known as Optical Brighteners that are suitable for this invention. These are discussed in US Patent No. 5, 759,349 mentioned above. These compounds include the stilbene and coumarin derivatives that shine under ultraviolet or infrared light. It is also important to estimate the concentration of the materials loaded in the lumen, in the paper against counterfeiting. The following is a step-by-step procedure to perform this calculation. For simplicity an individual pine fiber was modeled as a cylinder. The interior of the cylinder contains the material loaded in the lumen and the cell wall, relative density of 1.53 g / ml, which responds to the weight of the fiber. To make the most conservative estimate, the dimensions of the fiber were based on the minimum cell wall thickness and the maximum diameter of the fiber. The model for the fiber is used as shown below.

S = 1.5 μrn Calculation Step 1 - Calculate the volumes of the inner cylinder, the outer cylinder and the annulus.

V c. ilindro = pR2L Vintßrior = 2. 9 x 10"12m3 V ex erior - 3. 3 x 10-12m3 Vinulo = 4. 3 x 10" 13m3 Step 2 - Calculate the amount of material loaded in a fiber.

X (g) = CL (g / m3) x Vintßrior (m3) X = amount of ink in a fiber, convert it to grams (pounds) CL = Concentration of the solution loaded in the lumen Step 3_ - Calculate the weight of an individual fiber.

Assumption - the cell wall represents the total weight of a fiber.

Vínulo (m3) -r density of the cell wall = 1.5 x 10"'0.454 kg (Ib) = 7.5 x 10" "907.2 kg (tons) density of the cell wall = 2.96 x 10" 4 mVO.454 kg (m3) / lb) (United States Commercial Lumber, 1940; p52) Step 4 - Calculate the amount of lumen loaded material on the card stock. 0. 454 kg loaded fibers 1 fiber Zj (Ib) ink = X _ _x _ _ and _ __ 907.2 kg loaded fiber 1x10"total fibers 7.5xl0" iJ (ton) of paper 907.2 kg (tons) 0.454 kg 907.2 kg.,,, db) ink (1 ton), (ppm) = ¿, 907.2 kg 907.2 kg 1, 000,000 (ton) (2000 Ib) u = concentration of the fibers loaded on the cardboard, in ppm. Z-L = amount of material loaded in the lumen, on the cardboard, at 0.454 kg / 907.2 kg (pounds / tons). Z2 = concentration of material loaded in the lumen, on the cardboard, in ppm.

Typically, stained lumen-loaded wood fibers are added to the raw material in such a way that they form a small percentage of the total raw material. This percentage can be as low as a few parts per billion and up to 20-25%. In the preferred embodiment, individual wood fibers loaded in the lumen can be recognized under ultraviolet light or under infrared light. After the wood fibers loaded into the lumen, stained, are uniformly dispersed in the raw material, a counterfeiting paper is manufactured with it, through conventional operations for papermaking. The following example was prepared using the concepts of the present invention: EXAMPLE The fibers were loaded with various fluorescent, soluble agents. Each of these agents was dissolved in a solvent, such as methanol, at a concentration of 0.5 g / 1, 1 g / 1, and 10 g / 1 respectively. The pine was obtained and the water was removed up to 30% solids. Then, fifty dry grams were added to 2 liters of each solution and it was stirred conventionally with electric agitators for a time of approximately 3 to 4 hours. This was done under a ventilation hood and, during mixing, methanol was added to compensate for evaporation. Once the fibers were stained they were washed on a vacuum, with methanol and water, alternately, until the resulting solution was clear. This required approximately two to three liters of each material. The fibers were re-incorporated into the pulp form in a conventional laboratory disintegrator and four 30.48 x 30.48 cm (12 x 12 inch) test sheets were made from them. The disintegrator is normally used in the paper industry to distribute the fibers in an aqueous medium. When incorporating them again in the pulp form it was observed that there was no visible change in the color of the water in which the fibers were dispersed. The test sheets were then dried on a conventional drum dryer, thereby sealing the product within the fiber. Finally, the treated fibers were re-incorporated into the pulp form and added to hardwood fiber at a rate of 100 ppm and 1000 ppm and round 20.3 cm (8 inch) test sheets were produced. Once the above description is provided, many other characteristics, modifications or improvements will be revealed to the one experienced in the art. Those features, modifications or improvements are, therefore, considered a part of this invention, the scope of which will be determined by the following claims.

Claims (7)

NOVELTY OF THE INVENTION Having described the foregoing invention, it is considered as a novelty, and therefore, the content of the following is claimed as property: CLAIMS

1. A method for producing a counterfeiting paper, which can be detected with a light source of radiation, and the method is characterized in that it comprises the steps of: dissolving a fluorescent, soluble ink in a solvent; remove water from lumber fibers that have lumens, up to a solids content of up to 50% solids; mix the dissolved fluorescent ink with the wood fibers from which the water has been removed, so that the fluorescent ink is charged into the lumens of the fibers; cleaning the loaded wood fibers, to remove substantially any excess fluorescent ink, which is located on the outside of the lumens of the wood fibers; sealing the fluorescent ink substantially within the lumens of the wood fiber; remove the wood fibers loaded with the fluorescent ink; dry the loaded wood fiber; incorporate the wood fibers loaded in the lumen, clean, into a raw material consisting of paper pulp, at a concentration of Z2 of the total raw material, where Z2 (ppm) = concentration of the fibers loaded in the lumen, in the raw material = Z, x 907.2 kq f 1 ton) 1,000,000, 907.2 kg (2000 Ib) where Z, = quantity of fibers loaded in the lumen, in the raw material, in 0.454 kg / 977.2 kg (pounds / ton) of fiber, where the wood fibers loaded in the lumen, clean, are incorporated into the material premium at a concentration that is between at least one part per billion and up to 25%; to form, from the raw material loaded in the lumen, a role against falsification; and, wherein the fluorescent ink found in the fibers loaded in the lumen, can be detected using a light source of radiation.

2. The method in accordance with the claim 1, characterized in that the solvent further comprises methanol.

3. The method according to claim 1, characterized in that the water fibers are removed to wood fibers up to a solids content of less than 30% solids.

4. The method in accordance with the claim 1, characterized in that the fluorescent ink further comprises an optically active ink.

5. The method according to claim 1, characterized in that the light source of radiation further comprises an infrared light.

6. The method according to claim 1, characterized in that the light source of radiation further comprises an ultraviolet light.

7. The method according to claim 1, characterized in that Zx or the amount of fibers loaded in the lumen, in the raw material, in lb / tonne is estimated according to:

0. 454 kg 0.454 kg loaded fibers 1 fiber z? (Ib) ink =? (Ib) ink 907.2 kg loaded fiber lxlOb total fibers x 775x10 '"(ton) of paper 907.2 kg (tons) where u = concentration of charged fibers, in the raw material, in ppm, where x = amount of ink in a fiber.