JP4662459B2 - Thermal recording medium - Google Patents

Description

  The present invention relates to a thermal recording medium that can achieve both direct thermal printing and ribbon printing and has high anti-counterfeiting properties.

  Currently, commuter passes are gradually becoming non-contact IC cards in urban areas, mainly in the Tokyo metropolitan area. Because there are many passengers in the Tokyo metropolitan area and urban areas, if there are not many ticket gates, it will not be possible to reach within a certain time, and as a result, a large labor cost will be required. The machine has a non-contact IC card reading mechanism and a conventional magnetic commuter pass reading mechanism. However, passengers are sparse when they leave the city, and even if it is crowded, it is only a certain time in the morning and evening, and even if a non-contact IC card and a new gate machine are introduced, there are many places that do not get on the profit base.

  In such non-urban areas, it can be assumed that conventional visual and legible types and magnetic commuter passes will be used. Various types of magnetic commuter pass that can be read visually have been proposed and adopted in the past. Recently, the function of the ticket issuing machine has been improved, and red and black ribbon printing is available. Has been made. For women, the name field is printed in red, the type of commuting and attending school is highlighted in red, and the waypoints are printed in red. From these viewpoints of storage stability and stability, resin-based ribbons have been used.

  This is because the conventional wax ribbon, as the name suggests, is a low-melting-point component mainly used as a wax, so that the storage stability (particularly at high temperatures) is poor. However, commuter passes having a thermal layer called direct thermal are now in the spotlight. Since direct thermal has been using dyes (mostly leucos), storage stability is poor, and problems such as discoloration and fading due to heat and humidity are inevitable, but storage stability This is because it has become possible to provide a material having a certain heat resistance and water resistance, such as development of a color developer that excels in quality.

  Further, in the case of a commuter pass printed with a ribbon, since the ribbon is exposed on the outermost surface, the compatibility with the gate machine is not good. This is because the ribbon printing portion is gradually faded or dropped off due to the mechanism that feeds at a high speed by the conveyor belt of the gate machine, and eventually becomes invisible. On the other hand, in the case of direct thermal, for example, an OP agent can be applied to the outermost surface on the heat-sensitive color developing layer, so that it takes a considerable number of conveyances until the heat-sensitive color developing layer is scraped by the gate machine. Thus, if it is the expiration date of use of a commuter pass for a maximum of 6 months, it is not easy to see the visibly, so the compatibility with the gate machine is relatively good.

  As described in Patent Document 1, the OP agent contains a small amount of a peelable component such as silicone, PE wax, or fluorine. This is because the thermal head instantaneously becomes a high temperature of around 200 ° C., so if the surface slipperiness is poor, the contact time with the thermal head becomes longer as a result, and the time of exposure to high temperature becomes longer. This is because a phenomenon referred to as “occurrence” occurs and may result in uneven printing. In addition to the leuco dyes mentioned above, the thermosensitive coloring layer contains a developer and a binder component (a thermoplastic resin such as acrylic), so if it is exposed to high temperatures for a long time, it will melt or decompose. End up. In other words, in order to prevent sticking, it is essential that the OP agent has high heat resistance (→ therefore, UV curable resin or thermosetting resin is selected), but further, a peelable component is also essential. I can say that.

  When two-color printing is performed by direct thermal, a method is known in which a red coloring layer and a black coloring layer are sequentially laminated. A general method is to set the printing energy low for red printing, and set the printing energy high for black printing (when black color is developed after red coloring, it looks black). This generally indicates that the red color developing layer has lower heat resistance. Of course, the red coloring layer also has a certain level of heat resistance, but it must still develop from red. In other words, in everyday life, “If you place it near a heater, the entire surface would appear red.” In this case, you will go to the station to explain the circumstances and have it reissued.

  On the other hand, the collection commuter pass that has passed the deadline is processed at the station. In order to prevent the waste ticket processing from being reused by mistake, ribbon printing is generally performed on the surface of a collection commuter pass that has expired. Regardless of how much direct thermal is used, it is difficult to read even if the "Invalid Process" is printed after the necessary information has already been printed. This is because it is not suitable because it cannot be distinguished from an accident at home. That is, when used in a commuter pass, there is a demand for direct thermal printing at the time of ticketing without sticking and capable of ribbon printing at the time of waste. At this time, it was found that the general OP agent containing a release component cannot be used. If the release agent is contained in the OP agent, the fixability of the ribbon printing on the OP agent is poor, and the ribbon printing at the time of waste ticket cannot be performed normally.

  On the other hand, in the thermal card having a heat-sensitive color-developing material, the applicant of the present invention has a part having a peelable component on the outermost surface side in contact with the thermal head and a part having no peelable component. And a thermal card capable of ribbon printing, characterized in that they are formed of different types of UV or EB curable inks or coating agents. For practical use of such a thermal recording medium, it is required to further improve the forgery prevention property.

As a countermeasure against forgery, for example, as disclosed in Patent Document 3, there is a recording medium in which a heat-sensitive color-developing layer, a printing layer, and a light coherent reflection layer mixed with a pearl pigment are laminated on a substrate. In this case, the light-interfering reflective layer for preventing counterfeiting was conspicuous in appearance before recording thermal color development, and it was not yet satisfactory for preventing counterfeiting.
Japanese Patent No. 2757905 Japanese Patent Application No. 2004-142300 JP-A-9-169161

  Therefore, in order to solve the above-described problems, the present invention can achieve both direct thermal printing and ribbon printing, and there is no sticking at the time of direct thermal printing, and thermal recording has a very high anti-counterfeiting property. The purpose is to provide a medium.

In view of the above situation, the present inventors have intensively researched and developed, and found a thermal recording medium that can achieve both direct thermal printing and ribbon printing and has very high anti-counterfeiting properties. That is, according to the first aspect of the present invention, in the thermal recording medium having at least a part of the thermochromic material, a protective layer and a pattern layer are sequentially provided on the outermost surface side in contact with the thermal head. The component is higher than 300 dpi formed by UV curable ink or EB curable ink added at a mass ratio of 5% to 30% with respect to the pattern layer forming ink, and has a resolution with an upper limit of 500 dpi. It is a micro character and is characterized in that ribbon printing can be performed on the outermost surface by ribbon printing by a hot melt transfer method with a negative pattern shape of the pattern layer.

The invention according to claim 2 is characterized in that the thermal recording medium according to claim 1 is any one of a commuter pass, a boarding pass, a playing card, and an admission ticket.

The present invention relates to a thermal recording medium having at least a part of a thermosensitive coloring material, and a protective layer and a pattern layer are sequentially provided on the outermost surface side in contact with the thermal head, and the pattern layer is an ink for forming a pattern layer. In contrast, it is a micro character having a resolution higher than 300 dpi and having an upper limit of 500 dpi, which is formed with UV-curable or EB-curable ink added at a mass ratio of 5% to 30%, Ribbon printing can be performed on the outermost surface with a negative pattern shape of the pattern layer by ribbon printing by a hot melt transfer method. As a result, the print from the thermal transfer ribbon is not fixed on the pattern layer containing the silicone-based component in the above certain range, and the ribbon print is fixed on the protective layer without the pattern layer. The ribbon printing part is fixed in the shape of the negative pattern of the layer.

Further, the thermal recording medium can perform direct thermal printing at any location, and can achieve both direct thermal printing and ribbon printing. Further, the pattern layer, rather higher than 300dpi, by being formed at a resolution micro characters of up to 500 dpi, a resolution is difficult to reproduce in a thermal printer, because the pattern layer is formed The pattern layer cannot be forged by printing with a thermal printer. Therefore, the medium has a higher anti-counterfeiting property.

  FIG. 1 is a schematic view showing one embodiment of a thermal recording medium 1 of the present invention, in which a thermal coloring layer 3 containing a thermal coloring material and a protective layer 4 are sequentially provided on a substrate 2 for further protection. A pattern layer 5 containing a silicone-based component is provided on the layer 4. The illustrated thermal recording medium 1 includes a protective layer 4 and a pattern layer 5 on the outermost surface side in contact with the thermal head. FIG. 2 is a schematic diagram for explaining the pattern of the pattern layer of the thermal recording medium of the present invention and the state in which the pattern is raised after ribbon printing. The pattern layer shown in FIG. 2 includes a large number of “DNP” micro characters. The pattern layer pattern is formed with a resolution of, for example, 500 dpi. After ribbon printing with the “DNP” pattern on the pattern layer and the protective layer, as shown in the enlarged view, a solid DNP pattern is formed. A pattern layer in which a number of micro characters “DNP” are arranged appears in the portion. In the pattern layer, since the silicone component is contained in a certain range, the ribbon printing is not performed and the ribbon printing is performed on the adjacent protective layer.

Each layer constituting the thermal recording medium of the present invention will be described in detail below.
(Base material)
The thermal recording medium of the present invention has a thermosensitive coloring material at least in part, and a protective layer and a pattern layer are sequentially provided on the outermost surface in contact with the thermal head, and the silicone layer is used for forming the pattern layer in the pattern layer. Although it is the conditions formed with the ink added by 5% or more and 30% or less by mass ratio with respect to ink, using with the base material 2 which supports said part is preferable. This base material is made of a sheet-like, film-like or plate-like material, and the material is not particularly limited. Polyethylene terephthalate (PET), nylon, cellulose diacetate, polystyrene, polyethylene, polypropylene, polyester, polyimide, Plastics such as polyvinyl chloride and polycarbonate, metals such as copper and aluminum, paper, impregnated paper and the like can be used alone or in combination and laminated. The thickness of the substrate is suitably about 0.005 to 5 mm.

(Thermosensitive coloring layer)
In the thermal recording medium of the present invention, the thermosensitive coloring layer 3 is provided as a portion having the thermochromic material. This thermochromic layer contains a thermochromic material, and specifically includes an electron-donating dye precursor and an electron-accepting compound that develop color by a thermal melting reaction, and further, if necessary, a sensitizer and a color fading. Inhibitors, fillers such as pigments and lubricants, dispersants, binders and the like are included. The thermosensitive coloring layer is formed as a layer by coating or printing on the substrate. Examples of the method for forming the thermosensitive coloring layer include gravure, roll coating, spray coating, dipping, and others. As the electron donating dye precursor, one that is applied to this kind of heat-sensitive material as a leuco dye, or one that develops yellow, cyan, or magenta in the case of full color is selected. Specific examples of the electron-donating dye precursor include triphenylmethane, fluorane, phenothiazine, auramine, spiropyran, and indinophthalide, and are appropriately selected according to the color to be colored.

  Examples of the electron accepting compound include those used as a developer in combination with an electron donating dye precursor, such as phenolic substances such as bisphenol A, octylphosphonic acid, nonylphosphonic acid, decylphosphonic acid, and dodecylphosphonic acid. And organic acids such as tetradecylphosphonic acid, octadecylphosphonic acid, and epoxytetradecanoic acid, metal complex compounds, thiodiphenylurea, and quinones.

  Examples of the sensitizer include stearic acid amide, behenic acid amide, methylene bis stearic acid amide, dibenzyl oxalate, tolylbiphenyl ether, and fatty acid amides. Examples of the anti-fading agent include analogs of color developers blocked with hydroxyl groups, organometallic salts such as zinc salts, and hindered phenols. When the pigment is used in combination, the white pigment has an effect of scattering visible light and near infrared light to the surroundings, promotes near infrared light absorption into the light absorbent and increases heat generation efficiency. Examples of the pigment include calcium carbonate, aluminum hydroxide, silicate, zeolite, silica, kaolin clay, and urea formalin resin.

  For the formation of the thermosensitive coloring layer, an ink or a paint is prepared in order to form a layer made of the above materials. As a binder for ink or paint, a water-soluble resin is the main component, and examples thereof include polyvinyl alcohol, starch, methyl cellulose, hydroxyethyl cellulose, gelatin, casein, urea resin, melanin resin, amide resin, and polyurethane resin. Moreover, various adjuvants can be added as needed.

In the present invention, when the two thermosensitive coloring layers are formed, the upper layer and the lower layer are formed such that the coloring temperatures are different from each other. Preferably, a color former having a relatively low color development temperature (such as a red color developer) is used in the upper layer, and a color developer having a relatively high color development temperature (such as a black color former) is used in the lower layer. Those skilled in the art can easily determine the color formers having different color development temperatures by selecting the color former and the color developer. The thickness of the thermosensitive coloring layer is usually about 3 to 10 μm in each layer, and the coating amount when dried is about 3 to 10 g / m ² .

(Protective layer)
The thermal recording medium of the present invention has a configuration in which the protective layer 4 is provided on the thermosensitive coloring layer, that is, on the outermost surface side in contact with the thermal head. The protective layer of the present invention is the outermost layer of the thermal recording medium and protects the lower layer (thermosensitive color developing layer). In addition, the protective layer is practically formed of a substantially colorless and transparent protective layer ink to make it easy to read the color-recorded portion of the thermosensitive coloring layer that is protected underneath. It is desirable. As a material constituting the protective layer, a resin having transparency, scratch resistance, abrasion resistance, heat resistance, chemical resistance, stain resistance, and the like is suitable.

Examples of the resin constituting the protective layer include commonly used water-soluble resins such as polyvinyl alcohol, and UV curable or EB curable resins. In order to improve durability such as scratch resistance and abrasion resistance, UV curable or EB curable resins are preferably used. The thickness of the protective layer is about 3 μm or more, preferably 3 to 20 μm, and is about 3 to 20 g / m ^{2 in} terms of coating amount when dried. If the thickness is too small, the durability such as hardness, scratch resistance and wear resistance is insufficient. On the other hand, if it is too thick, the thermal sensitivity of the thermal recording medium is lowered, the adhesion to the thermosensitive coloring layer is lowered, and this is disadvantageous in terms of cost.

  The type of UV curable resin is not particularly limited as long as it is a monomer, oligomer, or prepolymer that is cured by a polymerization reaction by ultraviolet irradiation to become a resin, and various known ones can be used. . The OP layer usually contains a photopolymerization initiator in an ultraviolet curable resin component.

  Examples of prepolymers include aliphatic, cycloaliphatic, araliphatic to hexavalent polyhydric alcohols and polyalkylene glycol poly (meth) acrylates, poly (meth) acryloyloxyalkyl phosphate esters, polyester poly ( Vinyl or diene having (meth) acrylate, epoxy (meth) acrylate, polyurethane poly (meth) acrylate, polyamide (meth) polyacrylate, polysiloxane poly (meth) acrylate side chain and / or meta (acryloyloxy group) at the terminal And a prepolymer such as a low polymer. Examples of the monomer include alkyl esters of ethylenically unsaturated carboxylic acids, mono (meth) acrylates of alkylene oxide addition polymers of compounds containing active hydrogen, alkylene oxide addition polymers of compounds having active hydrogen, and (meth). Bifunctional monomer consisting of diester with acrylic acid, amide group-containing monomer represented by vinyl lactams such as N-vinylpyrrolidone, alkylene oxide addition polymer of compound having active hydrogen and (meth) acrylic acid And polyfunctional monomers made of polyester. Examples of photopolymerization initiators include benzophenone, 2-hydroxy-2-methyl-propiophenone, 1-hydroxy-cyclohexyl phenyl ketone, 2,4-diethylthioxanthone, and the like. It is added and used at a ratio of 5 to 10% by mass.

  The type of EB curable resin is not particularly limited, and specific examples include polyurethane acrylate, polyester acrylate, epoxy acrylate, polyether acrylate, etc., which adjust the viscosity or crosslinking density of each prepolymer. Therefore, a polyfunctional or monofunctional monomer may be added and used, and a known photopolymerization initiator or sensitizer may be added and used as necessary. In addition, polyene / thiol-based EB curable resins are also excellent in wear resistance and can be preferably used. For curing the UV curable resin or the EB curable resin, a conventionally known ultraviolet curing method or electron beam curing method is used.

  Prepare the UV curable resin or EB curable resin listed above, and ink with additives such as photopolymerization initiators as necessary, such as offset printing, letterpress printing, gravure printing, screen printing, etc. The protective layer can be formed by various printing methods and various coating methods such as air knife method, blade method, gravure method, roll coater method, spray method, dip method, and bar method.

(Pattern layer)
The thermal recording medium of the present invention has a configuration in which a protective layer and a pattern layer are sequentially provided on the outermost surface side in contact with the thermal head, and the pattern layer 5 has a silicone component of 5% or more with respect to the pattern layer forming ink. It is formed with the ink added at 30% or less. The ink for forming the pattern layer is prepared by mainly using a vehicle and adding pigments and additives as necessary according to printing methods such as offset printing, letterpress printing, and gravure printing. In the present invention, it is preferable to form the pattern layer with high definition, and when preparing a printing plate, it is preferable to form the pattern layer by offset printing which can be obtained in a relatively short time and at a low price.

As the pattern layer forming ink, an oxidation polymerization type ink can be used, but it is preferable to use a UV curable ink or an EB curable ink that is fast-drying and has good workability. As the UV curable or EB curable resin, photopolymerization initiator and the like constituting the pattern layer, the same protective layer as that described above can be used. On the other hand, it is added at a ratio of 5% to 30% by mass ratio . Examples of the silicone component include various silicone components. Particularly suitable are silicone three-dimensional cross-linked products such as silicone resins, silicone acrylates, and reactive silicone oils. Such a silicone-based component is added to the ink for forming the pattern layer, printed in a sufficiently dispersed state, and dried (crosslinked) so that the print from the thermal transfer ribbon is formed on the pattern layer. As a result, the ribbon is not printed on the pattern layer.

  The above-mentioned silicone acrylate has a molecular weight of about 500 to 10,000, a functional group equivalent (molecular weight / functional group) of about 400 to 8,000, and the functional group is a methacryl group, an acryl group, a mercapto when ultraviolet rays or electron beam curing is considered. Groups are preferred. Specific examples of silicone components include, for example, silicone oils such as dimethylpolysiloxane, methylhydrogenpolysiloxane, and methylphenylpolysiloxane, modified by alkyl, amino, epoxy, fluorine, carboxyl, alcohol, mercapto, etc. Examples thereof include silicone oil and a silicone macromonomer having a polymerizable functional group at one or both ends of a molecular chain. Preferred organopolysiloxane compounds include alcohol-modified silicone oils, alkyl-modified silicone oils, and silicone macromonomers having a (meth) acryloyl group as the one-end polymerizable functional group of the molecular chain. These known and commonly used organopolysiloxane compounds can be used alone or in combination of two or more.

The silicone component is contained in a mass ratio of 5% or more and 30% or less with respect to the ink for forming the pattern layer. However, if the silicone component is too small, In addition, the ribbon printing portion is fixed, and the ribbon printing with the negative pattern of the pattern layer is not performed. Moreover, when there are too many silicone type components from the said range, pattern layer itself will fall in adhesiveness with a protective layer. Further, the pattern layer is added with a vehicle such as the above-described UV curable or EB curable resin, and, if necessary, a white pigment such as titanium oxide or an additive. If the pattern layer is formed with a transparent or white hue, the pattern layer is hardly recognized in appearance before recording of thermal coloring, and the pattern layer appears only after recording and has anti-counterfeiting properties. This is because very high ones can be obtained.

  The pattern layer is preferably formed at a resolution higher than 300 dpi, and the pattern layer is formed at a resolution that is difficult to reproduce with a thermal printer. Cannot be reproduced by printing. Such a high-definition pattern layer can employ, for example, micro characters, background patterns, chromatic patterns, and the like. The thickness of such a pattern layer is about 1 μm or more, preferably 3 to 20 μm. If the thickness is too small, the pattern layer is likely to be blurred, and if the thickness is too large, the image reproducibility of the pattern layer is reduced.

  The thermal recording medium of the present invention has a configuration as shown in FIG. 1, and a conventionally known magnetic layer, hologram layer, etc. on the opposite side of the surface of the substrate 2 on which the thermosensitive coloring layer 3 is provided. Can be used for various purposes such as commuter pass, boarding pass, playing cards, admission tickets, etc.

A milk-white polyethylene terephthalate having a thickness of 188 μm is used as a base material, and γ-Fe ₂ O ₃ powder is dispersed in a binder solution composed of a vinyl chloride-vinyl acetate copolymer and a urethane resin on one surface of the base material. The magnetic coating agent thus formed was applied to the entire surface by a gravure reverse method to form a magnetic layer having a thickness of 15 μm. On the other side of the substrate, a thermosensitive coloring layer forming ink having the following composition was applied over the entire surface by a gravure reverse method to form a thermosensitive coloring layer having a thickness of 5 g / m ² when dried. Hereinafter, unless otherwise specified, parts or% is based on mass.

(Ink for forming thermosensitive coloring layer)
Black dye (3- (N-ethyl-N acylamino) -6-methyl-7anilinofluorane)
10 parts Developer (bisphenol A) 85 parts Solvent (polyvinyl alcohol 10% aqueous solution) 5 parts

Using the UV-curable ink manufactured by Dainippon Ink & Chemicals, Inc., and a protective layer forming ink (substantially colorless and transparent ink) under the trade name Grandic, on the above thermosensitive coloring layer, the entire surface is coated by a bar coating method After the coating, the film was irradiated with ultraviolet rays to form a protective layer having a thickness of 5 g / m ² when dried. Next, offset printing is performed on the protective layer using the pattern layer forming ink having the following composition, and ultraviolet rays are irradiated immediately after the printing, and “DNP” micro characters as shown in FIG. 2 are arranged. The patterned layer was formed with a thickness of 2 μm.

(Ink for pattern layer formation)
UV curable ink (Dai Nippon Ink Chemical Co., Ltd., trade name: Dicure ROP Varnish)
100 parts Silicone acrylate 7 parts

  The content of the silicone component in the UV curable pattern layer forming ink containing the silicone component is 7% (mass ratio) with respect to the pattern layer forming ink. The resolution of the printed pattern layer was 500 dpi. As described above, the thermal recording medium of Example 1 was produced. This thermal recording medium can be used as a commuter pass with direct thermal printing at the time of ticketing without sticking, and can be printed clearly. When ribbon printing was performed on the protective layer and the pattern layer, the ribbon printing was performed with the negative pattern shape of the pattern layer. That is, the print from the thermal transfer ribbon was not fixed on the pattern layer, and the ribbon print was fixed on the protective layer without the pattern layer. As a result, it was found that the thermal recording medium has a high anti-counterfeit property.

A thermal recording medium was manufactured in the same manner as in Example 1 except that the conditions of the thermosensitive coloring layer in the thermal recording medium manufactured in Example 1 were changed as follows. The black color thermosensitive coloring layer forming ink used in Example 1 was applied to the entire surface by the gravure reverse method to form a first thermosensitive coloring layer having a thickness of 5 g / m ² when dried. Next, on the first thermosensitive coloring layer, a red thermosensitive coloring layer forming ink having the following composition was applied over the entire surface by the gravure reverse method, and a second thermosensitive layer having a thickness of 5 g / m ² when dried. A coloring layer was formed.

(Ink for forming thermosensitive coloring layer)
Red dye (3-diethylamino-3-chlorofluorane) 10 parts Developer (3,3-dichlorophenthiourea) 85 parts Solvent (polyvinyl alcohol 10% aqueous solution) 5 parts

  The obtained thermal recording medium was a direct thermal print at the time of ticketing as a commuter pass, and there was no sticking and a clear red-black print was made. In addition, the red color printing could be performed by heating at about 80 ° C., and the black color printing could be performed by heating at about 100 ° C. In addition, as a waste ticket process, ribbon printing was performed on the surface of the commuter pass on which the thermal printing was performed by using a ribbon of a heat melting transfer method, and the ribbon printing was performed with the negative pattern shape of the pattern layer. That is, the print from the thermal transfer ribbon was not fixed on the pattern layer, and the ribbon print was fixed on the protective layer without the pattern layer. As a result, it was found that the thermal recording medium has a high anti-counterfeit property.

It is the schematic which shows one Embodiment of the thermal recording medium of this invention. It is the schematic explaining the pattern of the pattern layer of the thermal recording medium of this invention, and the state which this pattern rose after ribbon printing.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Thermal recording medium 2 Base material 3 Thermosensitive coloring layer 4 Protective layer 5 Pattern layer

Claims (2)

In the thermal recording medium having at least a part of the thermosensitive coloring material, a protective layer and a pattern layer are sequentially provided on the outermost surface side in contact with the thermal head, and the pattern layer has a silicone-based component for the pattern layer forming ink. It is a micro character having a resolution higher than 300 dpi and having an upper limit of 500 dpi, which is formed with UV curable ink or EB curable ink added at a mass ratio of 5% or more and 30% or less, and on the outermost surface, A thermal recording medium characterized in that ribbon printing is possible with a negative pattern shape of the pattern layer by ribbon printing in a hot melt transfer system. The thermal recording medium according to claim 1, wherein the thermal recording medium is one of a commuter pass, a boarding pass, a playing card, and an admission ticket .

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