Use of an epoxy-silicone copolymer, a crosslinkable fluid composition containing the same, and banknotes coated with the composition

Abstract

In particular, the present invention relates to the use of an epoxy-silicone copolymer, i.e., a branched polyorganosiloxane containing epoxide functional groups, for the production of a write-preventing surface coating for banknotes.

Description

【Technical Field】 【0001】 The present invention relates to the field of security documents. In particular, it relates to the use of epoxy-silicone copolymers, crosslinkable fluid compositions containing them, and banknotes coated with such compositions. 【Background Art】 【0002】 In the field of security documents, particularly banknotes, one of the reasons for central banks to withdraw some banknotes is that users write (generally by hand) on the surface of banknotes using writing instruments such as pens, pencils, and felt-tip pens. 【0003】 Writing or drawing on banknotes with portraits of living or deceased persons (kings, queens, chiefs, etc.) or banknotes representing national symbols or sacred beings is considered a crime in some countries, rather than just being withdrawn for aesthetic reasons. 【0004】 Current protective varnishes applied to the surface of banknotes provide barrier properties. That is, they can prevent the adhesion of dry dirt (evaluated by the Frietch test), the penetration of aqueous substances (water resistance or hydrophobicity, evaluated by the cob test), or the adhesion of fatty substances (fat resistance or oil resistance, evaluated by the kit test) on the surface and inside of banknotes. 【0005】 As an example, WO 2013 / 045496, which describes a varnish with high performance in terms of barrier properties, can be mentioned. 【0006】 To obtain these high barrier properties, those skilled in the art can examine macroscopic features that are assumed to reflect the attacks that circulating banknotes encounter, as described in the above example. On the other hand, physicochemical values that characterize the water-repellent effect and surface wettability in advance can also be directly measured, particularly by measuring interfacial tension and surface energy. 【0007】 WO 2014 / 067715 proposes a very effective varnish liquid for security documents, whose performance is evaluated only by surface tension measurement, and the most effective varnish liquid has a value of 25 mN / m or less. 【0008】 The surface energy of such a coating is very low, generally reflecting the difficulty of adhering to the surface of security documents. However, the applicant has found that such varnishes cannot sufficiently prevent or limit writing on banknotes. 【0009】 That is, it has been observed that writing on banknotes can be done relatively easily. Despite this low surface energy, as long as the substances (such as ink) used for writing are not dry, what is written with certain pens, fluorescent pens, or pencils may be erasable. In contrast, for example, oil-based ballpoint pens and markers are difficult to erase. Furthermore, it has been observed that it is particularly difficult to erase completely without leaving a trace after drying. 【0010】 Furthermore, it can be easily understood that the procedure for systematically erasing graffiti on banknotes implemented by central banks is very difficult or impossible to execute unless a machine for cleaning banknotes without damaging them is developed. This will significantly increase the time and cost of sorting before the banknotes can be put back into circulation. 【0011】 In a completely different field, it is known to apply anti-graffiti treatments to the surfaces of concrete, wood, stone / bricks, metals, etc. 【0012】 In this case too, a low surface energy can be obtained by such treatments. However, the term "anti-graffiti" is misleading. In fact, it is still possible to write graffiti or apply paint to the surface with a pen or spray can (tag), but the implemented treatment makes subsequent erasure more or less easy. This makes it possible to erase the graffiti completely or almost completely. 【0013】 In addition, this prior art is disclosed in each of the documents of International Publication No. 2015 / 091873, Japanese Patent Application Laid-Open No. 11-199673, U.S. Patent Application Publication No. 2016 / 060398, and International Publication No. 2001 / 53385. 【0014】 From the above, it can be seen that there is still an unmet need for varnishes that are applicable to security documents, particularly surface coating formulations applicable to banknotes, i.e., not only having the above barrier properties (resistance to dry dirt, water, and oil), but also anti-writing properties that make it impossible or at least difficult to write on a substrate coated with the varnish. Therefore, it can prevent the general public from using banknotes as "Post-it (registered trademark)", reminders, or a way to "vent anger" against individuals or symbols of power. 【0015】 The expression "anti-writing" or "writing resistance" means the resistance of a coating applied on paper or a plastic substrate for banknotes to writing. In other words, it means that the ink of the pen used during writing tends to remain at the pen tip, form droplets on the substrate surface (non-continuous lines, water-repellent), or is difficult to adhere (continuous lines but thin and "bleed" easily). 【0016】 In the context of the present invention, this "anti-writing" property is the subject of evaluation of instrumental and visual properties based on the standard specification ASTM D6578, "Determination of Erasability Resistance", adapted to a specific case of security documents, and a test specially developed this time to reflect the difficulty of writing on the substrate and thus deter writing. More specifically, the "anti-writing" property is the subject of the writing resistance evaluation described below. 【Summary of the Invention】 【0017】 This object is achieved by the present invention. For this object, the present invention relates first to the use of an epoxy-silicone copolymer, i.e., a branched polyorganosiloxane containing an epoxide functional group, for the production of an anti-writing surface coating for banknotes. 【0018】 Also related is a method for producing a write-preventing surface coating for banknotes based on an epoxy-silicone copolymer, i.e., a branched polyorganosiloxane containing epoxide functional groups. 【0019】 Preferred but non-limiting embodiments of such uses and methods are as follows. 【0020】 The polyorganosiloxane corresponds to one of the following formulas. 【Chemical formula】 【Chemical formula】 In the formula, R is a hydrocarbon group that is the same as or different from each other, R 1 is a hydrogen atom or a hydrocarbon group that is the same as or different from each other, R 2 is a hydrocarbon group having at least one carbon atom that may contain an oxygen atom, n ≧ 1 and m ≧ 1 and n > m, and n and m are integers, R 3 is a hydrocarbon group having at least one carbon atom, X is a carbon atom, and its index o is 0 or more. 【0021】 The polyorganosiloxane corresponds to one of the following formulas. 【Chemical formula】 【Chemical formula】 In the formula, R 4 is a methyl group or a chemically stable methylene bridge within cyclohexyl, and the combination of formula (b) and formula (c') is excluded. 【0022】 The polyorganosiloxane corresponds to formula (c). 【0023】 The present invention secondly relates to a fluid composition that can be crosslinked under ultraviolet irradiation, the fluid composition comprising a cationic crosslinked matrix and an epoxy-silicone copolymer, i.e., a branched polyorganosiloxane containing epoxy-functional groups. 【0024】 Preferred but non-limiting embodiments of such a composition are as follows. 【0025】 The polyorganosiloxane corresponds to one of the following formulas. 【Chemical formula】 【Chemical formula】 In the formula, R is a hydrocarbon group that is the same as or different from each other, R 1 is a hydrogen atom or a hydrocarbon group that is the same as or different from each other, R 2 is a hydrocarbon group having at least one carbon atom that may contain an oxygen atom, n ≧ 1 and m ≧ 1 and n > m, and n and m are integers, R 3 is a hydrocarbon group having at least one carbon atom, X is a carbon atom, and its index o is 0 or more. 【0026】 The polyorganosiloxane corresponds to one of the following formulas. 【Chemical formula】 【Chemical formula】 In the formula, R 4 is a methyl group or a chemically stable methylene bridge within cyclohexyl, and the combination of formula (b) and formula (c') is excluded. 【0027】 The cationic crosslinked matrix preferably contains 50% by weight or more of a cycloaliphatic diepoxide. 【0028】 The polyorganosiloxane is contained in an amount of 5% by weight or more, preferably 5 - 15% by weight, more preferably 8 - 12% by weight. 【0029】 The above composition further contains PFPE - tetraurethane acrylate in a mixture with ethyl acetate and butyl acetate. 【0030】 PFPE - tetraurethane acrylate is contained in an amount of 0.5% by weight or more, preferably 0.5 - 5% by weight, more preferably 2 - 4% by weight. 【0031】 Thirdly, the present invention relates to a banknote having a write - preventing surface coating formed from a composition of any of the above - described embodiments, wherein at least one of the opposing surfaces crosslinks under ultraviolet irradiation. 【0032】 Preferred but non - limiting embodiments of such banknotes are as follows. 【0033】 When at least one surface is intaglio - printed or calendered, the write - resistance evaluation of the write - preventing surface coating exceeds 8.5, and if not, it exceeds 4.5. Preferably, when at least one surface is intaglio - printed or calendered, the write - resistance evaluation exceeds 10, and if not, it exceeds 6. More preferably, when at least one surface is intaglio - printed or calendered, the write - resistance evaluation exceeds 13, and if not, it exceeds 9. 【Embodiments for Carrying Out the Invention】 【0034】 I. Evaluation of Write - Resistance of Banknote Samples Coated with Varnish Two evaluations were conducted to clarify the following. · Ease of erasing marks on the sample according to ASTM D6578, "Determination of Resistance to Marking" · Difficulty of writing on the sample by a method specially developed to address this issue 【0035】 A. Mark Erasure Test According to Modified ASTM D6578 i. Equipment and Materials Related to the Mark Erasure Test According to Modified Standard ASTM D6578 Microfiber cloth Spectrophotometer, model DC45IR from DATACOLOR Gloss meter, model 4450MicroTRIgloss from BYK 【0036】 Pens for the tester: · Permanent marker black, Pentel pen N50 (hereinafter MIN) from Pentel Co., Ltd. · Blue ballpoint pen, SOFTfeelMED (hereinafter SBB) from BIC · Red rollerball pen, V - ball 0.5 pure liquid ink (hereinafter SMR) from PILOT · Erasable marker green, WHITEBOARD MARKER VELLEDA (hereinafter MEV) from BIC · Refillable fluorescent pen pink, model number 70 / 56 (hereinafter SFR) from Stabilo Boss Original 【0037】 The selection of pens for the tester and the related references / marks do not exactly match those specified in ASTM D6578. What is actually shown are permanent markers / erasable markers / rollerball pens / spray paints / colored wax crayons. 【0038】 The last two examples have been replaced with a blue ballpoint pen and a pink fluorescent pen. This is because spray paints and wax crayons are not considered for writing on banknotes unless one wants to turn the banknote into an art piece. Additionally, the colors are generally selected to cover a wide spectral range. 【0039】 Cleaning agent: · MEK (Methyl Ethyl Ketone) · Xylene · Gasoline (a mixture of C6 - C7 alkanes, with the proportion of n - hexane less than 5%) · IPA (Isopropyl Alcohol) · 5% Aqueous Sodium Phosphate Solution · Dry white cotton cloth 【0040】 The 5% sodium phosphate solution was prepared at the following ratio. · 5 g of trisodium phosphate dodecahydrate · 95 g of deionized water 【0041】 ii. Conducting the test Color an area of at least 1 cm × 0.5 cm with each of the above - mentioned writing means. Before conducting the erasure test, let the lines dry for at least 24 hours (the drying time is 48 hours or less). 【0042】 After drying, use the specified cloth and conduct a mark - erasure test with each of the cleaning agents in the above list. Indicate the cleaning agent used next to the erased mark. 【0043】 iii. Evaluation by equipment Using a spectrophotometer, measure the following two characteristics for each mark (a total of 30 measurement areas, marks of 5 pens to be erased × 6 types of cleaning agents (5 solutions + 1 dry type)): · ΔE (color difference): The difference between the selected sample area before marking and the residual mark after cleaning. Measure different locations on the residual mark three times and calculate the average value. If ΔE ≤ 2, the mark is considered to be completely erased. · Gloss rate ΔGloss (measured at 60°): The difference between the selected sample area before marking and the residual mark after cleaning. Measure different locations on the residual mark three times and calculate the average value. For the varnish film to be considered unchanged, this ratio must be 0.9 or more. 【0044】 iv. Evaluation scale Based on the measurement results of ΔE and ΔGloss, the following evaluation is given (when ΔE ≤ 2 and the gloss rate ≥ 0.9, mark erasure). 【0045】 【Table 1】 【0046】 When an evaluation of 4 or more is applied in 0.5 unit increments, this means that the ΔE by a less aggressive cleaner (in order of increasing aggressiveness: MEK, xylene, gasoline, IPA, 5% aqueous sodium phosphate solution) is close to 2 (2 ≤ ΔE ≤ 4). For example, when ΔE ≤ 2 with xylene and 2 ≤ ΔE ≤ 4 with gasoline, the evaluation is 6.5. 【0047】 Although this test is derived from existing standards, as a result of preliminary tests conducted by the applicant, it has been found that this standard is insufficient to fully characterize the desired write resistance. 【0048】 More specifically, it was observed that for a certain manufacturer's tester pen, it becomes particularly difficult to erase when the ink dries. Paradoxically, however, it is particularly difficult to write on the treated banknote, which may therefore discourage people from trying to write persistently. Therefore, a second evaluation was created to visually characterize the difficulty of writing on the sample. 【0049】 B. Write Difficulty Evaluation Test i. Test Implementation and Evaluation Lines were drawn at several locations on the sheet with each tester pen. This is exactly the same as adapting the above-mentioned standard ASTM D6578 to security documents, but in this evaluation, the behavior of "new" lines (i.e., lines just drawn) is evaluated. 【0050】 Therefore, this evaluation is carried out visually, and the evaluation is applied according to the evaluation scale detailed below. 【0051】 ii. Evaluation Scale The evaluation is carried out according to the following cases for the quality of the "new" line, especially its continuity, water repellency, and density. 【0052】 【Table 2】 【0053】 With a 0.5 increment, more accurate comparison between various samples becomes possible. Between 0 and 1.5, the evaluation is based on the density of the line. From 2 onwards, the evaluation is made by observing the water repellency and the density of the line. 【0054】 C. Writing Resistance Evaluation Test Considering that the writing resistance depends on the ease of erasing and removing scribbles and also largely depends on the difficulty of writing on the substrate, it is evaluated on a scale of 20 points, and as follows, a weight of 2 is assigned to the second evaluation. Writing Resistance Evaluation = (Mark Erasure Test Evaluation according to Modified ASTM D6578) + 2 × (Evaluation of the Difficulty of Writing Test). 【0055】 II. Barrier Property Evaluation Test A. Frietchu Test The Frietchu test, well-known in the banknote printing industry, was used to examine the stain resistance. A vibrating device is used in this test. Small glass beads are spread in a test tube of paper, and a stain composition based on sand, peat, activated carbon, wheat flour, and glycerol monooleate (a fatty substance particularly contained in sebum) is adhered. 【0056】 The test time is 15 minutes. First, the luminance of the white part is measured several times before and after exposure to the stain composition. The obtained difference (ΔL) can be used to judge how much the stain adheres to the banknote. The smaller the difference, the higher the resistance to dry stains. 【0057】 B. Cob Test according to ISO 535:2014 Standard Hydrophobicity is the resistance to water penetration and at the same time the ability to repel water on the surface, which is also called water repellency. The resistance to water penetration is measured for 60 seconds by the cob test. In this test, a cylindrical impregnation device is used to measure the amount of water absorbed by the substrate in g / m 2 per unit in 60 seconds. This test is also common in the paper industry to evaluate the absorbency of paper. 【0058】 Kit test according to C.TAPPI T569 standard Oil resistance or grease resistance is measured using an exposure test to fatty substances. In the "kit test" method, a mixture of castor oil (a fatty substance) and a high-boiling solvent, namely toluene (an aromatic solvent) and n-heptane (an aliphatic solvent), is used. 【0059】 Due to the difference in the ratio of the above products, a composition can be obtained in which the viscosity and surface tension vary inversely with its aggressiveness, i.e., the impregnation ability. 【0060】 The more the composition is rich in castor oil, the lower the evaluation level, and the more the composition is rich in heavy solvent, the higher the evaluation level. 【0061】 There are 12 types of compositions. Evaluation 0 means zero oil repellency, and evaluation 12 means maximum oil repellency. 【0062】 III. Printing protocol For all samples, in order to reflect the conventional surface state of banknotes intaglio-printed on one side, a white paper with a white intaglio (without ink) calendared on the front and a 100% cotton bellarm paper are overprinted with the protective varnish to be tested. Generally, the barrier properties of the varnish are higher on the side with intaglio calendaring (harder paper). 【0063】 The samples are flexographically printed with anilox (front / rear) of 6 cm 3 / m 2 and dried with an IST200W / cm mercury spectrum UV lamp (65% output). 【0064】 IV. Preliminary work The applicant already had a high-performance varnish solution dedicated to banknotes as an attempt to solve the raised technical problems. 【0065】 Therefore, this varnish known under the brand name of "ULTRA" was tested and compared with a standard product known in the currency market and widely used for banknotes, namely the varnish "SICPAPROTECT (registered trademark)" with reference number 889368 sold by SICPA. 【0066】 Hereinafter, these two varnishes will be referred to as "ULTRA varnish" and "reference varnish". 【0067】 First, the barrier properties were evaluated. 【0068】 The average results of the front and back surfaces of the barrier properties of the ULTRA varnish are as follows. 【0069】 【Table 3】 【0070】 Subsequently, the above-mentioned test was carried out and supplemented with surface energy measurement (see the last line of the following table). 【0071】 【Table 4】 【0072】 Surprisingly, although there was clearly a high barrier property compared to the reference varnish at a varnish amount of about 2 g / m 2 on one side, the ULTRA varnish did not show the expected writing resistance. 【0073】 Anyway, the ULTRA varnish has better writing resistance than the reference varnish, but this improvement is very limited and thus reinforcement is required. 【0074】 To explain these results, supplementary measurements were carried out, particularly to evaluate the surface tension. As expected, the surface tension of the ULTRA varnish is approximately half that of the reference varnish, but surprisingly, this has not clearly led to good results with regard to the expected writing resistance. 【0075】 Therefore, the applicant conducted research to understand and test new formulations that can exhibit the desired writing resistance and provide solutions to the aforementioned problems. 【0076】 Cationic polymerization varnishes generally provide effective protective coatings for banknotes (such as the reference varnish mentioned above). 【0077】 Also, the barrier properties of cationic varnishes can be improved by selecting an appropriate amount of reactive additives. 【0078】 Therefore, perfluoropolyether-type compounds (characteristic of ULTRA varnishes) are very effective in significantly improving barrier properties as described above, but are not very effective in terms of writing resistance. 【0079】 As an alternative, the use of silicone-based additives such as siloxanes can be considered. These additives are not randomly selected. More specifically, as follows, in addition to chemical properties, they have economic and ecological advantages, and also advantages in terms of safety in use. · Classified as non-dangerous goods. · Have a high flash point, especially exceeding 94°C. · Road transportation does not require the Agreement concerning the International Carriage of Dangerous Goods by Road (ADR). · Do not generate volatile organic compounds (VOCs). · Generally, they are less costly than perfluoropolyether compounds. 【0080】 To conduct comparative tests of various silicone-based additives, preliminary tests for discrimination purposes were carried out on samples of siloxane-based additives. 【0081】 The following table summarizes chemical substance information obtained from the Technical Data Sheet (TDS) and the Safety Data Sheet (FDS). Multiple different products obtained from different suppliers were evaluated at different ratios. 【0082】 【Table 5】 【0083】 The screening preliminary test conducted here and shown in Table 6 below is based on a writing difficulty test using only two types of pens, a red roller ball pen and a pink fluorescent pen, in this upstream process. Based on the results of these pens, various varnishes to be tested can be discriminated. The reference varnish is the cationic polymerization varnish SICPAPROTECT889368. The ULTRA varnish is the second reference varnish, which is a reactive perfluoropolyether urethane compound with acrylate terminals, that is, a compound formulated with Fluorolink AD1700 (registered trademark, hereinafter AD1700) sold by Solvay. 【0084】 【Table 6】 【0085】 This preliminary test is to confirm the previous results for the reference varnish SICPAPROTECT889368 and the ULTRA varnish (reference varnish + 8% AD1700). The latter showed interesting results with the pink fluorescent pen (SFR), but very low results with the red roller ball (SMR). 【0086】 The reference varnish is mainly cationically polymerized, but in particular, it also contains compounds capable of radical reactions for optimal three-dimensional crosslinking. This is the reaction mode used in perfluoropolyether-urethane acrylate additives, which gives excellent barrier properties but no expected writing resistance and is not of at least truly important dimensions. 【0087】 Among the silicone products tested according to the concentrations recommended by the seller, surprisingly, although some have acrylate functional groups, none exhibited desirable writing resistance. 【0088】 Ring-opening polymerization of epoxides by cationic initiation is the main polymerization method used in reference varnishes. Cationic initiation occurs, for example, under ultraviolet irradiation, by cationic photopolymerization initiators including triarylsulfonium hexafluorophosphate salts (e.g., Speedcure 992 from Lambson) or diphenyl(4-phenylthio)phenylsulfonium hexafluoroantimonate (e.g., DC1176 from Comexim). The main base-reactive compound is the cycloaliphatic diepoxide with CAS number 2386-87-0 and official name 3,4-epoxycyclohexylmethyl 3,4-epoxycyclohexanecarboxylate. This compound is particularly available from Cytec (trade name UVACURE 1500) or Comexim (trade name DOUBLE MER420P). 【0089】 The applicant of the present application sought a "twin" compound in terms of chemical functionality, i.e., a compound having a reactive epoxide functional group and still having a siloxane structure. Therefore, epoxy-functionalized polyorganosiloxane compounds were tested. 【0090】 These compounds are usually used to form hydrophobic and non-sticky film-forming coatings, for example, on paper or synthetic plastic substrates, in particular to reversibly promote the peeling of adhesive materials applied to these substrates, such as labels and adhesive tapes. 【0091】 Despite the expected chemical compatibility, adding these compounds may well not result in the expected write resistance as already described above. When using additives with the same reactive chemical function as more than 50% by weight of the cationic reagent in the formulation, the cycloaliphatic diepoxide with CAS number 2386-87-0 may be buried in the substance and have no effect at all, or it may be necessary to add it in large quantities economically. In the worst case, it may destabilize the formulation, causing harmful or unexpected effects. 【0092】 The same simplified protocol was also used for Elkem's Silcolease® solvent-free UV series epoxy-silicone additives, reference numbers POLY204, RCA200 and POLY215, and Shin-Etsu Chemical Co., Ltd.'s reference numbers X-62-7660 and X-62-7622. 【0093】 [Table 7] 【0094】 In Table 7, promising preliminary results regarding write resistance were obtained in this simple test using the above compounds, so the applicant decided to conduct this test. The coating amount of the varnish is 1.6 ± 0.3 g / m² on the front side 2 , and 2.3 ± 0.3 g / m² on the back side 2 . The results are shown below. 【0095】 [Table 8] *Surface: R = front side, V = back side (1) Eff = Evaluation of the mark erasure test according to ASTM D6578 ( / 10 points) (2) Dif = Evaluation of the writeability evaluation test ( / 5 points) 【0096】 The results of 5 tester pens were totaled and averaged to obtain the following comprehensive evaluation. 【0097】 [Table 9] *Surface: R is the front surface, V is the rear surface (1) Eff = Evaluation of the mark erasure test according to ASTM D6578 ( / 10 points) (2) Dif = Evaluation of the writing difficulty evaluation test ( / 5 points) (3) Writability evaluation = (1) + 2×(2) 【0098】 Among all the additives tested, POLY204, X-62-7660, and X-62-7622 gave the best results when added at 10% to the reference varnish. These varnishes exhibited very satisfactory writability compared to the reference varnish and the ULTRA varnish. 【0099】 To confirm that no adverse effects were brought about by the addition of POLY204, the barrier properties from the above tests were evaluated with the reference varnish, ULTRA varnish, reference varnish with 10% POLY204 added, reference varnish with 15% POLY204 added, reference varnish with 10% POLY204 and 3% AD1700 added, reference varnish with 10% X-62-7660 added, and reference varnish with 10% X-62-7622 added. 【0100】 【Table 10】 *Surface: R = front surface, V = rear surface (3) "x - y" indicates the evaluation between evaluations x and y. 【0101】 Regarding the dry and soil resistance test (Fritsch), no significant difference was observed between the ULTRA varnish and the varnish formulated with 10% POLY204, 10% X-62-7660, and 10% X-62-7622. In terms of water resistance (blistering) and grease resistance, the varnish formulated with 10% POLY204 is superior to the reference varnish but interestingly inferior to the ULTRA varnish. Also, the varnish formulated with 10% POLY204 and 3% FLOROLINK AD1700 showed performance equivalent to that of the ULTRA varnish in the blister test and was only 1 point lower than the ULTRA varnish in the kit test. Since the siloxane additive is less expensive than the perfluoropolyether additive, it is doubly interesting in terms of efficiency and economy. The varnishes formulated with 10% X-62-7660 or 10% X-62-7622 also showed very interesting results. Especially for X-62-7660, although the oil resistance result is 2 points lower than that of the ULTRA varnish, the water resistance is excellent and superior to the ULTRA varnish that does not use a perfluoropolyether additive. 【0102】 Therefore, the problem raised in the foregoing was solved by formulating an epoxidized polyorganosiloxane additive into a varnish that dries by ultraviolet irradiation and mainly undergoes cationic polymerization. The writeability, based on both the ease of erasing written lines and the difficulty of new writing on banknotes, can be satisfied with a relatively low proportion of the additive, while generally maintaining important barrier properties, bringing about substantial environmental benefits as described above, and ultimately being able to suppress an increase in manufacturing costs.

Claims

[Claim 1] Use of epoxy-silicone copolymers, i.e., branched polyorganosiloxanes containing epoxide functional groups, for the manufacture of anti-write surface coatings for banknotes. [Claim 2] The aforementioned polyorganosiloxane corresponds to one of the following formulas: 【Chemistry 1】 【Chemistry 2】 In the formula, R is an identical or different hydrocarbon group. R １ These are hydrogen atoms or hydrocarbon groups that are identical or different from each other. R ２ This is a hydrocarbon group having at least one carbon atom, which may contain an oxygen atom. n ≥ 1 and m ≥ 1 and n > m, where n and m are integers. R ３ is a hydrocarbon group having at least one carbon atom, The use of the polyorganosiloxane according to claim 1, wherein X is a carbon atom and its index o is 0 or greater. [Claim 3] The aforementioned polyorganosiloxane corresponds to one of the following formulas: 【Transformation 3】 【Chemistry 4】 In the formula, R ４ The use of the polyorganosiloxane according to claim 1, wherein is a methyl group or a chemically stable methylene bridge within cyclohexyl, and the combination of formula (b) and formula (c') is excluded. [Claim 4] The polyorganosiloxane is the polyorganosiloxane according to claim 3, which corresponds to formula (c). [Claim 5] A fluid composition that can be crosslinked under ultraviolet irradiation, comprising a cationic crosslinking matrix and a branched polyorganosiloxane containing an epoxy-silicone copolymer, i.e., an epoxide functional group. [Claim 6] The aforementioned polyorganosiloxane corresponds to one of the following formulas: 【Transformation 5】 【Transformation 6】 In the formula, R is an identical or different hydrocarbon group. R １ These are hydrogen atoms or hydrocarbon groups that are identical or different from each other. R ２ This is a hydrocarbon group having at least one carbon atom, which may contain an oxygen atom. n ≥ 1 and m ≥ 1 and n > m, where n and m are integers. R ３ is a hydrocarbon group having at least one carbon atom, The fluid composition according to claim 5, wherein X is a carbon atom and its index o is 0 or greater. [Claim 7] The aforementioned polyorganosiloxane corresponds to one of the following formulas: 【Transformation 7】 【Transformation 8】 In the formula, R ４ The fluid composition according to claim 6, wherein is a methyl group or a chemically stable methylene bridge within cyclohexyl, and the combination of formula (b) and formula (c') is excluded. [Claim 8] The fluid composition according to claim 5, wherein the cationic crosslinking matrix comprises a cycloaliphatic diepoxide. [Claim 9] The fluid composition according to claim 5, wherein the polyorganosiloxane is contained in an amount of 5% by weight or more. [Claim 10] The fluid composition according to claim 5, further comprising PFPE-tetraurethane acrylate in a mixture of ethyl acetate and butyl acetate. [Claim 11] The fluid composition according to claim 10, wherein the PFPE-tetraurethane acrylate is contained in an amount of 0.5% by weight or more. [Claim 12] A banknote having a write-proof surface coating formed from a fluid composition according to any one of claims 5 to 11, wherein at least one of the opposing surfaces is crosslinked under ultraviolet irradiation. [Claim 13] The banknote according to claim 12, wherein if at least one of the surfaces is intaglio printed or calendared, the write resistance rating of the write-resistant surface coating is greater than 8.5, and otherwise it is greater than 4.5.