JP2006168084A - Laminated coating film structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a laminated coating film structure capable of individually and concretely specifying the origin and history of a product by using nucleic acid subjected to information processing. <P>SOLUTION: A discrimination layer containing the nucleic acid subjected to information processing, which is equipped with a region having an arbitrary or known base sequence, is provided to the lower layer of a clear coating film layer. The nucleic acid subjected to information processing is added in an amount of 0.5-500 μg/m<SP>2</SP>as the amount per the unit surface area of an article to be coated and supported on fine particles with a mean particle size of 0.01-2 μm. The fine particles are added in a ratio of 0.5-50% with respect to the surface area of the article to be coated. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a multilayer coating film structure, and more particularly to a multilayer coating film structure using an information nucleic acid that can be used for individual authentication.

  Conventionally, for individual authentication, a license plate, watermark printing such as banknotes, an IC chip and a photo of a credit card are used. However, these individual authentication means have a drawback that they can be removed from the product by peeling, cutting, erasing or the like. For this reason, it has been expected to develop authentication information that cannot be removed from the product, that is, does not disappear.

On the other hand, DNA is an information biomolecule originally possessed by all living organisms and including all genetic information in each organism. Many of them correspond to the amino acid sequences of many proteins. That is, deoxyadenosine (dA), deoxyguanosine (dG), deoxycytosine (dC), and deoxythymine (dT) are bonded with a certain direction through a phosphate ester bond, and the number of bases is n. Thus, there are ⁴ⁿ types of DNA having that length. Thus, for example, there can be about 4.3 billion types of distinguishable DNAs with only 16 types of bases. At present, any DNA having a sequence of several tens of bases can be arbitrarily synthesized. In addition, if the amount of DNA exceeds a certain level, the sequence can be automatically determined by an automatic sequence reader (sequencer).

From such a background, it has been proposed to use a forgery-preventing label in which DNA is contained in a water-insoluble medium in a product to clarify the authenticity of the product based on the presence or absence of the DNA. (See Patent Document 1).
JP 2004-159502 A

  However, the technique described in Patent Document 1 basically relates to a method of mixing DNA and a water non-solvent, and as a product authenticity confirmation method, the presence or absence of amplification of ribonucleic acid by the PCR method is confirmed. This indicates that the target product containing ribonucleic acid is identified. In addition, authenticity verification data that uses the presence / absence of DNA as a test index is data related to individual authentication that uses DNA sequence as a test index and enables authentication for each product even for the same type of product. Is not disclosed.

  On the other hand, in the case of theft / damage of articles such as vehicles, there is a demand for identifying the target article at an early stage from the paint piece of the article left on the scene of the incident.

  The present invention has been made in view of such problems of the prior art, and the object of the present invention is to individually identify the source / history product by containing information nucleic acid. It is providing the laminated coating film structure which can be specified concretely.

  As a result of intensive studies to solve the above-mentioned problems, the present inventors considered a nucleic acid typified by DNA as one piece of authentication information, and later detects the information nucleic acid in the laminated coating film structure, The present inventors have found that the above problems can be solved and have completed the present invention.

  According to the present invention, even if it is a mass-produced product such as an industrial product, the target product can be individually authenticated by determining the sequence of the contained information nucleic acid.

  Hereinafter, the laminated coating film structure of the present invention will be described in detail. In the present specification and claims, “%” indicates a mass percentage unless otherwise specified.

  The laminated coating film structure of the present invention has an identification layer containing an information nucleic acid provided with a site having an arbitrary and known base sequence below the clear coating film layer. This identification layer can be easily applied to a product as a kind of paint, and it is difficult to remove it from the product after the coating film is formed, so that it can be used as an excellent individual authentication means.

  Here, the above-mentioned information nucleic acid refers to DNA (deoxyribonucleic acid), RNA (ribonucleic acid) and derivatives thereof, which may be natural or artificial, but should be included in the laminated coating film structure where the usage environment is severe. In consideration, it is preferable to use an artificial mold that is structurally stable. In the artificial type, a sequence having a binding mode that does not exist in the natural type (for example, a linkage between nucleosides includes not only a phosphate ester bond but also a non-natural type such as a thiophosphate ester bond) can be formed.

  In addition, in the above-mentioned information nucleic acid, that the base sequence site is arbitrary means that it can be randomly selected as long as it is a detectable base sequence, and that the base sequence site is known is used for individual authentication. It shows that the base sequence to be grasped in advance.

  As for the size of the information nucleic acid, the number of bases in the whole nucleic acid is preferably 200 or less. When it exceeds 200, unreacted sites are generated little by little at the stage of synthesis, and the content of those lacking a base tends to increase. More preferably, it is about 100 bases. Furthermore, it is preferable that thymines are not adjacent to each other in the above base sequence. Thereby, it can suppress that thymine dimerizes.

  In addition, the information nucleic acid is preferably derivatized with a protecting group from the viewpoint of improving stability when used in combination with a compound that reacts with an OH group or when used in a severe environment. Specifically, a hydroxyl group at one or both of the 5′-position and the 3′-position is derivatized with a phosphate ester group, an acyl group, an alkoxycarbonyl group, a benzyl group, a substituted benzyl group, an allyl group, or the like. can do. FIG. 1A shows natural DNA, and FIG. 1B shows DNA derivatized at the 5 ′ position.

  Furthermore, from the viewpoint of enhancing the convenience of isolation and purification, it is preferable to derivatize the hydroxyl group at the 5 ′ position with biotin or a fluorescent molecule. Specifically, when vithion is used, it is easily adsorbed selectively on a column to which a protein called avidin is bound. On the other hand, when a fluorescent molecule such as fluorescein is used, the nucleic acid itself becomes fluorescent, so that it can be detected with high sensitivity and purification is facilitated. Thus, when the convenience of isolation and purification is increased, individual authentication becomes extremely easy.

  When RNA is used as the information nucleic acid, the 2′-position hydroxyl group can be derivatized with the protecting group from the viewpoint of improving stability.

  Further, from the viewpoint of efficiently detecting the information nucleic acid even when the content in the identification layer of the laminated coating film structure is small, the base sequence site is a site used for amplification of the information nucleic acid. Preferably there is. As a method for amplifying such information nucleic acid, polymerase chain reaction (PCR) that can be amplified synergistically can be appropriately employed.

  Typically, it is desirable to employ a PCR method that can be amplified extremely even if the information nucleic acid is extremely small. In this method, for example, when a thermostable DNA polymerase is allowed to act while controlling the temperature in the presence of a base (primer) complementary to several tens of bases of the DNA, the original DNA can be doubled. If this is repeated 30 times, for example, it can be amplified several hundred million times. This amplification makes it possible to obtain a sufficient amount to determine the sequence even from a very small amount of sample, and in turn the product containing the information nucleic acid from the information corresponding to the sequence (laminated coating film structure) Will be revealed.

  In this case, it is preferable that the sites used for the amplification have primer-corresponding sites necessary for polymerase chain reaction (PCR) at both ends. This is because an information nucleic acid can be used without a primer, but it can be identified in a short time by providing a primer.

  For such a primer corresponding site, the lower limit of the number of bases is preferably 5 or more. More preferably, it is 10 or more. If the number of bases is less than 5, the number of nucleic acids that can be distinguished decreases, and when many products (laminated coating film structures) are mixed, it takes time to identify them. On the other hand, the upper limit of the number of bases is preferably 100 or less. When the number of bases exceeds 100, the ratio of by-products lacking a base at any position increases, and purification takes time, or in some cases, purification becomes difficult.

  In addition, when RNA is used as the information nucleic acid, DNA complementary to the sequence can be obtained using reverse transcriptase, and PCR can be performed using this DNA.

  The information nucleic acid preferably further has an authentication information site in addition to the base sequence site. In this case, individual authentication can be executed by more detailed information setting.

  For example, as shown in FIG. 2, in the case of information-oriented DNA having primer-corresponding sites at both ends, a sequence with m bases is placed in the center (B1 to Bm), and the sequence information of this portion is used as authentication information. Make it correspond. At both ends, sequences (X1 to Xl, P1 to Pn) complementary to l (el) and n primers are ligated, respectively. The presence of this part makes it possible to adopt the PCR method for the first time. The information DNA can be used as an information element of this single-stranded DNA or a double-stranded DNA complexed with a complementary sequence of DNA. The sequence of the primer corresponding site can be devised so that the binding of complementary sequences is as stable as possible and amplification by the PCR method proceeds smoothly.

Furthermore, in the identification layer of the laminated coating film structure, the information nucleic acid content should be 0.5 to 500 μg / m ² as the amount per unit surface area of the object to be coated. This is preferable from the viewpoint of improving the dispersibility in the layer. More preferably 50-100 [mu] g / ^{m 2,} it is good particularly preferably 60 to 80 [mu] g / ^{m 2.} When the content is less than 0.5 μg / m ^2, it is difficult to identify the information nucleic acid from the identification layer. If it exceeds 500 μg / m ² , the adhesion area of the clear coating layer, which is the upper layer of the identification layer, is reduced, and peeling tends to occur.

  As the raw material of the identification layer, information nucleic acid can be dissolved or dispersed in water or a solvent. In addition to the information nucleic acid, this raw material can appropriately contain various additives such as organic pigments, inorganic pigments, dispersants, and curing accelerators.

  The information nucleic acid may be applied alone, but is preferably carried on fine particles. As a result, it is possible to suppress the outflow of the information nucleic acid contained in the raw material of the identification layer from the raw material, thereby realizing a long life of the identification layer.

  Furthermore, the average particle size of the fine particles is preferably 0.01 to 2 μm from the viewpoint of improving the detection accuracy of the information nucleic acid and the dispersibility of the identification layer material, and more preferably, the average particle size is preferably 0.2. It is good that it is 02-1 micrometer. If the average flow diameter is smaller than 0.01 μm, the detection accuracy tends to be lowered, and if it is larger than 2 μm, the transparency tends to be lowered.

  Furthermore, the content of the fine particles is preferably 0.5 to 50% of the surface area of the object to be coated, so that the detection accuracy of the information nucleic acid and the dispersibility in the identification layer material are good. It is suitable from a viewpoint to do. More preferably, it is 5 to 30%, and particularly preferably 10 to 20%. If the content is less than 0.5%, the amount of fine particles in the sampled identification layer is too small, and the detection accuracy may be reduced. If it exceeds 50%, the adhesion area of the clear coating layer, which is the upper layer of the identification layer, is lowered and peeling tends to occur.

  As the fine particles, for example, titanium oxide, molybdenum oxide, tungsten oxide, barium titanate and the like are preferably used in addition to silica and zinc oxide. The fine particles are dispersed in sterile distilled water to form a suspension, and the information nucleic acid is added to the suspension as it is or an information nucleic acid aqueous solution in which the information nucleic acid is dissolved in sterile distilled water is added. It can be manufactured by drying. At this time, a part of the information nucleic acid may be added as it is without forming an aqueous solution, and the rest may be added in the state of an aqueous solution.

  At this time, the suspension includes alcohol (eg, methanol, ethanol, propanol, butanol, pentanol, hexanol, heptanol, octanol, nonanol, etc.), ester (eg, ethyl acetate, butyl acetate, propyl acetate, etc.) ), Ketones (for example, acetone, dimethyl ketone, methyl ethyl ketone, diethyl ketone, etc.) and aromatic solvents (toluene, hexane, cyclohexane, xylene, etc.) are preferably further added to the suspension of the fine particles. As well as improving dispersibility, the volatilization of water and solvent after the addition of the information nucleic acid is promoted.

  In addition, these solvents are not limited to only 1 type, It is also possible to use 2 or more types of solvents together. These solvents may be added at the same time as the information nucleic acid or after the information nucleic acid is added.

  As the amount of the solvent added, in the case of alcohol, the volume ratio of sterilized distilled water / alcohol is preferably in the range of 1 to 99. In the case of a solvent other than alcohol, that is, the ester, ketone, aromatic solvent In some cases, the volume ratio of sterile distilled water / solvent is preferably in the range of 1 to 75.

  That is, if the addition amount of the solvent is too small, the above-mentioned effect due to the addition of the solvent cannot be obtained sufficiently, and conversely, even if it is too much, the water tends to remain without volatilization due to a decrease in compatibility with water. There is a tendency to become insufficient.

  Next, the laminated coating film structure of the present invention will be described in detail. The laminated coating film structure is formed on an arbitrary base material and solidified. For example, as shown in FIG. 3, the lowermost undercoat coating layer 1, the intermediate coating layer 2, and the base A layer 3, an identification layer 4, and an uppermost clear coating layer 5 are provided, and the identification layer 4, which is the lower layer of the clear coating layer 5, contains information DNA having a primer corresponding site.

  Further, the thickness of the identification layer is not particularly limited, but is preferably about 20 to 30 μm from the viewpoint of the detection accuracy of the information nucleic acid.

  In addition, as said arbitrary base material, various inorganic materials, such as various metal materials, such as iron, aluminum, and copper, various organic materials, such as a polypropylene and a polycarbonate, quartz, and ceramics (calcium carbide etc.), are mentioned typically. . Moreover, as a method of coating these with a laminated coating film structure, a known and commonly used method can be employed. For example, a brush coating method, a spraying method, an electrostatic coating method, an electrodeposition coating method, and a sputtering method can be used. Further, the identification layer only needs to be coated in a range where the information nucleic acid can be detected, and can be coated on the whole or a part of the substrate.

  In the laminated coating film structure described above, individual authentication can be performed by detecting the information nucleic acid in the identification layer.

  At this time, in determining the base sequence, it is desirable to compare the information nucleic acid data extracted from the identification layer with the information nucleic acid database including at least the information nucleic acid data. The time required for product authentication can be significantly reduced by comparing with a database of information nucleic acids that has been grasped in advance.

  Examples of data stored in such a database include electrophoresis time and movement distance when gel filtration is performed (this is sufficient if the information nucleic acid itself is allowed to flow in the control lane).

  In the individual authentication method, when the information nucleic acid is amplified by the PCR method, the extracted information nucleic acid solution, PCR buffer solution, sterile distilled water, at least one primer, 2,3-dideoxynucleoside triphosphate Acid (dNTP) and polymerase are mixed, (1) heated at 92-95 ° C. for 2-5 minutes, then (2a) at 92-95 ° C. for 30-60 seconds, (2b) at 20-50 ° C. for 30- It is preferable that the heating cycle of (2c) at 70 to 80 ° C. for 30 to 120 seconds is repeated 20 to 50 times for 60 seconds, and then (3) heat treatment is performed at 70 to 80 ° C. for 1 to 10 minutes. In addition, it is preferable to use two types of primers from the viewpoint of enhancing the arbitraryness of the base sequence of the information nucleic acid.

  In (1), 5 minutes at 94 ° C. is particularly preferable. If it is shorter than 2 minutes at 92 ° C., it will be difficult to separate the DNA into two differences, and if it is longer than 5 minutes at 95 ° C., the enzyme will be inactivated. Note that this is unnecessary when the information nucleic acid contained in the identification layer is single-stranded.

  Further, in (2a), 30 seconds at 94 ° C. is particularly preferable. When the temperature is shorter than 30 seconds at 92 ° C., the amplification factor decreases, and when it is longer than 60 seconds at 95 ° C., the enzyme is inactivated.

  Further, in (2b), 30 seconds at 40 ° C. is particularly preferable. When it is shorter than 30 seconds at 20 ° C., it becomes difficult to bind the primer and DNA, and when it is longer than 60 seconds at 50 ° C., the enzyme is inactivated.

  Further, in (2c), 30 seconds at 72 ° C. is particularly preferable. If it is shorter than 30 seconds at 70 ° C., the elongation becomes insufficient, and if it is longer than 120 seconds at 80 ° C., the enzyme is deactivated.

  Further, in (3), 7 minutes at 72 ° C. is particularly preferable. If it is shorter than 1 minute at 70 ° C., the elongation becomes insufficient, and if it is longer than 10 minutes at 80 ° C., time is wasted.

  Furthermore, the repetition of the heating cycles (2a) to (2c) is particularly preferably 30 times. When the heating cycle is less than 20, the amplification factor decreases, and when it is more than 50, time is wasted.

  FIG. 4 shows a flowchart of an embodiment of the individual authentication method. As shown in the figure, in S1, information DNA is extracted from the identification layer of the laminated coating film structure. In S2, it is concentrated by lyophilization. In S3, two kinds of primers and a polymerase are added. In S4, DNA is amplified by repeating PCR. In S5, the remaining excess primer is degraded by a single-stranded DNA cleavage enzyme. In S6, the double-stranded information DNA is purified by gel filtration. In S7, sequencing is performed by a sequencer.

  Here, in S1, for example, the identification layer or the laminated coating structure including the identification layer may be powdered and mixed with a small amount of water. For example, when the information DNA is chemically bonded to the fine particles, Can be extracted efficiently by hydrolysis or the like. Moreover, in S2, you may concentrate using a centrifugal evaporator, for example. Further, in S5, for example, Taq DNA polymerase, Tth DNA polymerase, Tfl DNA polymerase, Vent polymerase, Pfu polymerase, Bca BEST polymerase, KOD DNA polymerase and the like can be used as the single-stranded DNA cleaving enzyme. Further, the target DNA may be amplified between S6 and S7 by repeating the same operations as in S3 and S4. In S7, sequencing may be performed by a mass spectrometer, or may be combined with sequencing by a sequencer.

  From the viewpoint of enhancing the convenience of isolation and purification of the information nucleic acid, it is preferable to derivatize the 5′-position hydroxyl group with biotin or a fluorescent molecule. Specifically, when vithion is used, it is easily adsorbed selectively on a column to which a protein called avidin is bound. On the other hand, when a fluorescent molecule such as fluorescein is used, the nucleic acid itself becomes fluorescent, so that it can be detected with high sensitivity and purification is facilitated. Thus, when the convenience of isolation and purification is increased, individual authentication becomes extremely easy.

  Furthermore, for example, when the 5′-position is substituted with sulfur, it can be easily separated by passing the column extracted with water through a carrier column coated with gold (Au).

  Hereinafter, the present invention will be described in more detail by way of examples, but the present invention is not limited to these examples.

1. Immobilization of informational DNA having primer-corresponding sites on microparticles (1) 15 mL of 30% ethanol-containing sterilized distilled water was added to and suspended in 4 g of microparticles having different particle sizes.
(2) 10 nmol (200 μm) of computerized DNA was dissolved in 0.5 mL of sterile distilled water, and this was added to the fine particle suspension and stirred sufficiently. Further, 4 mL of ethanol was added and stirred.
(3) The suspension was poured into a plastic circular dish, and the upper part was covered with air-permeable paper or cloth and allowed to air dry for 2 days.
(4) The suspension was almost dried and placed in a desiccator, and dried under reduced pressure under heating at 40 ° C.
(5) The sufficiently dried solid was crushed with a mortar or the like into a fine powder.

2. Fine particles used (1) Average particle size: 0.02 μm: ZS-032 (Zinc oxide) manufactured by Showa Denko KK
(2) Average particle size of 40 μm: AW40-74 (aluminum oxide) manufactured by Micron Corporation
(3) AW50-74 (aluminum oxide) manufactured by Micron Corporation with an average particle size of 60 μm

3. Preparation of coating solution (information material for identification layer) containing informational DNA with primer-corresponding sites 0.4 g of microparticles with immobilized informational DNA with primer-corresponding sites were dispersed in 1000 g of distilled water. .

4). Formation of multi-layer coating film Cathodic electrodeposition paint (trade name “Power Top U600M”, cation type electrodeposition paint manufactured by Nippon Paint Co., Ltd.) is dried on a dull steel plate with a thickness of 0.8 mm and 70 mm × 150 mm treated with zinc phosphate. After electrodeposition coating so that the thickness was 20 μm, baking was performed at 160 ° C. for 30 minutes. Thereafter, a gray intermediate coat (trade name: Hyepico No. 500) manufactured by Nippon Oil & Fats Co., Ltd. was applied at 30 μm and baked at 140 ° C. for 30 minutes.

  Next, a base coat (Superlac M180 BKH3 manufactured by Nippon Paint Co., Ltd.) is applied, baked at 140 ° C. for 30 minutes, and then a dispersion of fine particles on which information DNA having a primer corresponding site is immobilized (identification layer) 10 g) was baked at 80 ° C. for 10 minutes. Then, a clear paint (Superlac 0-130 GN3 manufactured by Nippon Paint Co., Ltd.) was applied and baked at 140 ° C. for 30 minutes to obtain a five-layer laminated coating structure.

  About the obtained laminated coating-film structure of Examples 1-22, the detection of DNA, moisture resistance (adhesiveness), smoothness, and color consistency were evaluated as follows.

<Detection of information DNA>
(1) The test piece containing the information nucleic acid was cut into pieces using a cutter.
(2) 5 mL of sterilized distilled water was added to the test strip and stirred with a magnetic stirrer to extract DNA into the aqueous layer.
(3) The test strip and the aqueous layer were separated using a centrifuge, and the aqueous layer was concentrated using a centrifugal evaporator.
(4) DNA solution (5 μL) eluted and collected, PCR buffer (5 μL), Taq polymerase (0.25 μL), sterile distilled water (24.75 μL), 5 μM primer 1 (5 μL), 5 μM primer 2 (5 μL) , And 2 mM dNTP (5 μL).
・ Primer 1 ... 5'-TGCACGCACCGTGTACTC-3 '
・ Primer 2 ... 5'-CCGACCAACGTGTCCACT-3 '
(5) After heating at 94 ° C. for 5 minutes, [94 ° C. for 30 seconds → 40 ° C. for 30 seconds → 72 ° C. for 30 seconds] was repeated 30 times.
(6) After being treated at 72 ° C for 7 minutes, it was stored at 4 ° C.
(7) Using a single-stranded DNA cleaving enzyme (S1 nuclease), the excess primer was decomposed, and the target double-stranded information DNA was purified by gel filtration.
(8) One kind of primer (primer 1: 5′-TGCACGCACCGTGTACTC-3 ′) and fluorescently labeled 2,3-dideoxynucleoside triphosphate were mixed with the purified information DNA.
(9) The same operations as in the above steps (4) to (6) were performed.
(10) After gel filtration purification, it was subjected to sequencing by using an automatic sequencer.
As shown in Tables 1 and 2, when these steps were performed and detection of informational DNA was attempted, it was found that identification of the informational DNA was easy, and that further PCR treatment was necessary. It was.

<Evaluation of moisture resistance (adhesion)>
After leaving it in an atmosphere of 50 ° C. and relative humidity of 95% for 500 hours, it was taken out and checked for adhesion. The adhesion force is determined by drawing the parallel lines of 11 vertical and horizontal lines that reach the coating substrate with a cutter knife (specified in 7.2 (2) (e) of JIS K 5400) at intervals of 2 mm. A cross-cut was formed. A cellophane tape (specified in JIS Z 1522) was brought into close contact with the grid-like coating film and peeled upward at a stretch, and the number of grids remaining in the 100 grids was measured. The results are shown in Tables 1 and 2.

<Evaluation of smoothness (appearance)>
As shown in Tables 1 and 2, the state of the surface was visually judged, and as shown in Tables 1 and 2, the case where the surface was good was indicated by ◯, the case where the surface was rough, and the case where the surface was considerably bad as x.

<Evaluation of color consistency>
Except for the absence of a discriminating layer, it was visually evaluated in comparison with the laminated coating film structure equivalent to each example. The thing with white taste was set as x.

  As is clear from Tables 1 and 2, all of the laminated coating film structures of Examples 1 to 12 can be identified with good informational DNA, and have a good appearance and good adhesion. In other words, the desired appearance can be obtained with the same workability as normal coating, and the coating film can be identified.

  On the other hand, the laminated coating film structures of Examples 13 to 16 resulted in a decrease in the discriminability of the information DNA because the content of the information DNA in the discrimination layer was less than the preferred range of the present invention. In the laminated coating film structures of Examples 17 to 22, any one of the content of information DNA, the particle size of fine particles, and the amount used deviates from the preferred range of the present invention. At least one of smoothness and color consistency occurred.

This is a structural formula showing natural DNA and DNA derived from this 5 'position. It is the schematic which shows the information nucleic acid which has a primer in both ends in an authentication information site | part. It is a cross-sectional schematic diagram which shows an example of the laminated coating film structure containing an identification layer. It is a flowchart which shows an example of an individual authentication method.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Undercoat coating film layer 2 Intermediate coating film layer 3 Basecoat layer 4 Information-ized DNA containing identification layer provided with primer 5 Clear coating film layer

Claims (6)

  A laminated coating film structure comprising an identification layer containing an information nucleic acid provided with a site having an arbitrary and known base sequence, under the clear coating film layer. ^2. The multilayer coating film structure according to claim 1, wherein the content of the information nucleic acid in the identification layer is 0.5 to 500 μg / m ² .   The laminated coating film structure according to claim 1 or 2, wherein the information nucleic acid is carried on fine particles.   The multilayer coating film structure according to claim 3, wherein the average particle diameter of the fine particles is 0.01 to 2 μm.   The multilayer coating film structure according to claim 3 or 4, wherein the content of the fine particles is 0.5 to 50% of the surface area of the article to be coated.   The laminated coating film structure according to any one of claims 1 to 5, wherein a material for the identification layer is obtained by dissolving or dispersing information nucleic acid in water or a solvent.

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