Patent ID: 12260280

DETAILED DESCRIPTION

(1) RFID Label

The following describes an RFID label1of one embodiment with reference toFIGS.1and2.

FIG.1is a plane view of a plurality of RFID labels1temporarily attached to a separator7with an adhesive.FIG.2is an enlarged view of an X-X cross section inFIG.1. The arrow “F” illustrated inFIG.1coincides with a conveyance direction in a manufacturing apparatus100, which will be described later.

As shown inFIG.2, the RFID label1of the one embodiment is a label in which a thermal paper2serving as a label substrate, an antenna3, an IC chip4, and an adhesive-for-adherend6are stacked in this order.

The thermal paper2includes a substrate21and a thermosensitive color developing layer22that is provided on one surface of the substrate21.

In this disclosure, a substrate of any material that is provided with a thermosensitive color developing layer on its surface can be applied for the “thermal paper”, and the substrate is not limited to those having a paper-based substrate. For example, a film can also be used as a substrate of the thermal paper2.

Examples of the material that can be used as the substrate21of the thermal paper2shown inFIG.2include papers such as fine papers and coated papers, single films of resin such as polyvinyl chloride, polyethylene terephthalate, polypropylene, polyethylene, and polyethylene naphthalate, and multilayer films formed by stacking a plurality of one or more types of these resin films.

An undercoat layer (adhesion-facilitating layer or barrier layer) may be provided between the thermosensitive color developing layer22and the substrate21. The surface of the thermosensitive color developing layer22may be provided with an overcoat layer (protective layer, lubrication layer, or ultraviolet light resistant layer).

The thickness of the thermal paper2, which is the same as the thickness of a continuous body “C” described later, is preferably 25 μm or greater and 300 μm or less. In the case of using a paper as the substrate21, the thickness can be set to 50 μm or greater and 260 μm or less, within the above-described range. In addition, in the case of using a resin film as the substrate21, the thickness can be set to 16 μm or greater and 200 μm or less, within the above-described range. The thickness of the thermal paper2can be selected as appropriate depending on the purpose.

The antenna3is made of a conductive material having a predetermined shape, as shown inFIG.1. The shape of the antenna3is not limited to the antenna pattern illustrated inFIG.1and can be set as appropriate depending on the purpose of use of the RFID label1. For example, the shape is designed to have a pattern corresponding to a certain frequency band, such as the UHF band (300 MHz to 3 GHz, and in particular, 860 MHz to 960 MHz), a microwave frequency band (1 to 30 GHz, and in particular, around 2.4 GHz), or the HF band (3 MHz to 30 MHz, and in particular, around 13.56 MHz).

The conductive material for forming the antenna3may be a metal foil, but not limited thereto, and any conductive material can be used.

In the case of using a metal foil as the antenna3, the material of the metal foil is, for example, copper or aluminum. In view of reducing production cost, aluminum is preferably used. Moreover, from the point of view of the total thickness and production cost of the RFID label1, the thickness of the antenna3, which is the same as the thickness of a continuous body “M” of a metal sheet described later, is preferably 3 μm or greater and 25 μm or less.

Examples of an adhesive “A” include acrylic adhesives, urethane adhesives, silicone adhesives, and rubber adhesives. Among them, ultraviolet curable acrylic adhesives are preferably used.

The adhesive strength of the adhesive “A” is preferably 500 gf/25 mm or greater, more preferably 800 gf/25 mm or greater, and further preferably 1000 gf/25 mm or greater, in a 180-degree peel test (JIS Z 0237). The upper limit of the adhesive strength is preferably 2000 gf/25 mm.

As shown by a further enlarged view of a part in the vicinity of the IC chip4inFIG.2, anisotropic conductive paste of ultraviolet curable anisotropic conductive adhesive, which is abbreviated as “ACP” in the drawings and in the descriptions hereinafter, is placed at a center part of the antenna3. The IC chip4is placed on the ACP.

An ultraviolet curable anisotropic conductive adhesive is an adhesive that cures upon being irradiated with ultraviolet light (UV), and it contains uniformly dispersed conductive particles. The ultraviolet curable anisotropic conductive adhesive joins the IC chip4to a predetermined position of the antenna3while providing conductivity between the IC chip4and the antenna3.

The dimensions of the conductive particles contained in the ACP can be determined as appropriate in accordance with, for example, surface roughness of the antenna3. The dimensions of the conductive particles are preferably 10 μm or greater and 30 μm or less, in order to ensure stable electrical connection.

As shown inFIG.2, the substrate21of the thermal paper2is provided with the adhesive-for-adherend6, on the entire surface on a side opposite to the surface provided with the thermosensitive color developing layer22. The adhesive-for-adherend6is used to attach the RFID label1to the separator7. In order to increase adhesion of the adhesive-for-adherend6, an undercoat layer may be disposed on the surface to be provided with the adhesive-for-adherend6, of the substrate21of the thermal paper2. A barrier layer for preventing permeation of the adhesive-for-adherend6may also be provided.

Examples of an adhesive that can be used as the adhesive-for-adherend6include emulsion adhesives (adhesives dispersed in water), solvent adhesives (adhesives dissolved in solvent), and hot-melt adhesives (thermoplastic adhesives). The material of this adhesive may be a synthetic rubber material, a natural rubber material, an acrylic resin material, a polyvinyl ether resin material, a urethane resin material, a silicone resin material, or the like. The adhesive strength of this adhesive can be set as appropriate depending on the application of the RFID label1.

The separator7can be, for example, a paper or film that is coated with ultraviolet curable silicone, thermosetting silicone, solvent silicone, alkyl pendant polymer, or fluorine release agent.

(2) Method for Manufacturing RFID Label

Next, a method for manufacturing the RFID label1of the one embodiment will be described with reference toFIG.3.FIG.3is a schematic diagram of a manufacturing apparatus100that executes some steps in the method for manufacturing the RFID label1of the one embodiment. The manufacturing apparatus100is used to execute a process of forming antennas3on a thermal paper2(hereinafter referred to as an “antenna forming process”) in manufacturing the RFID label1.

As shown inFIG.3, the antenna forming process includes an adhesive placement process P1, a metal sheet placement process P2, a cut-forming process P3, a removal process P4, and a pressurizing process P5that are executed while a continuous body “C” of a thermal paper2is conveyed. The adhesive placement process P1is performed to place an adhesive “A” on the continuous body “C” of the thermal paper2. The metal sheet placement process P2is performed to place a continuous body “M” of a metal sheet on a surface disposed with the adhesive “A” of the continuous body “C.” The cut-forming process P3is performed to form cuts for antennas3, in the continuous body “M” of the metal sheet. The removal process P4is performed to remove unnecessary parts Mb that do not constitute the antennas3, from the continuous body “M” of the metal sheet. The pressurizing process P5is performed to pressurize the antennas3remaining on the continuous body “C.” The arrow “F” inFIG.3shows the conveyance direction.

The adhesive placement process P1is executed by an adhesive placement unit110. The adhesive placement unit110includes an adhesive tank111for storing the adhesive, a drawing-up roller112for drawing up the adhesive from the adhesive tank111, a printing plate roller113for receiving the adhesive “A” from the drawing-up roller112and printing the continuous body “C,” and an impression cylinder114. In addition, the adhesive placement unit110also includes a UV lamp115for emitting ultraviolet light to the adhesive “A.”

The printing plate roller113has a plate cylinder that is wound with printing plates, which are formed with protrusion patterns113acorresponding to the shape of the adhesive “A” to be placed on the continuous body “C” of the thermal paper2. The printing plate roller113is formed with the plurality of protrusion patterns113a. The plurality of protrusion patterns113aare imposed to be arranged in a feed direction and a width direction of the printing plate roller113. Thus, a plurality of adhesives for antenna patterns are printed on the continuous body “C” at the same time. Each protrusion pattern113ahas a shape so as to be inside an outer circumferential line of the antenna3that is placed on the continuous body “C” of the thermal paper2.

Examples of the adhesive “A” that can be used in the adhesive placement process P1include acrylic adhesives, urethane adhesives, silicone adhesives, and rubber adhesives, as described above. In this antenna forming process, ultraviolet curable acrylic adhesives are preferably used from the point of view of performing flexography or relief printing to place the adhesive “A” on the continuous body “C” that is being conveyed. Alternatively, it is also possible to employ screen printing.

The thickness of the adhesive “A” that is placed on the continuous body “C” is preferably 3 μm or greater and 25 μm or less. The adhesive “A” having a thickness of 3 μm or greater has an adhesive strength sufficient to adhere to the antenna3, and the adhesive “A” having a thickness of 25 μm or less is not pressed out of the outer circumferential line of the antenna3by pressurizing. In view of this, the thickness of the adhesive “A” is more preferably 3 μm or greater and 10 μm or less.

FIG.4is a partially enlarged view of a partially cut main part “S” on a back side of an in-process RFID label1in the antenna forming process. In the enlarged part of the in-process RFID label1shown inFIG.4, a part underlying the antenna3of the adhesive “A” is represented by dashed lines. In addition, margins between the outer circumferential line of the antenna3and the adhesive “A” placed inside thereof are denoted by “mu,” “md,” “w1,” and “w2,” inFIG.4.

The placement position of the adhesive “A” is determined so that the margin “mu” on an upstream side in the conveyance direction will be wider than the margin “md” on a downstream side in the conveyance direction. That is, the margin “mu” shown inFIG.4is greater than the margin “md.”

Excessively large margins can cause the antenna3to rise at an edge or come off. On the other hand, excessively small margins can cause the adhesive “A” to spread beyond an outer circumference of the antenna3. In view of this, the margin “mu” is preferably 50 μm or greater and 300 μm or less, whereas the margin “md” is preferably 30 μm or greater and 100 μm or less, in the condition in which a relationship “mu>md” is satisfied.

In an embodiment, a process of printing reference marks may be executed prior to the adhesive placement process P1. The reference marks can be used as references for positioning the adhesives in printing the continuous body “C” and as references for determining cut positions in making cuts for the antenna patterns.

The metal sheet placement process P2is executed by a metal sheet placement unit120. The metal sheet placement unit120includes a pressing roller121and a support roller122. In the metal sheet placement process P2, the continuous body “M” of the metal sheet is conveyed in a conveyance path different from the conveyance path of the continuous body “C” and is overlaid on the surface on which the adhesive “A” has been placed of the continuous body “C.” Then, the continuous bodies “C” and “M” are inserted between the pressing roller121and the support roller122to be bonded together. The adhesive is not present at a part outside the outer circumferential line of the antenna3, and therefore, the continuous body “M” of the metal sheet does not adhere to the continuous body “C” except for areas in which the antennas3are to be formed.

The cut-forming process P3is executed by a cut-forming unit130. The cut-forming unit130includes a die roll131for making cuts for the antennas3, in the continuous body “M” of the metal sheet placed on the continuous body “C,” and it also includes an anvil roller132for supporting the die roll131from below. The die roll131has a surface formed with projecting blades131athat have a shape corresponding to the outer circumferential line of the antenna3. The projecting blade131acan be a flexible die. Alternatively, it is also possible to use an engraving blade, an implanted blade, or the like, for the projecting blade131a.

The cut-forming unit130causes the projecting blades131ato cut into the continuous body “M” of the metal sheet to define the antennas3, while nipping and continuously conveying a work having the continuous bodies “C” and “M.” This forms cuts in the continuous body “M” of the metal sheet.

The removal process P4is executed by a removal unit140. The removal unit140includes peeling rollers141and142. The unnecessary parts Mb of the metal sheet are fitted along a part of the peeling roller141and are changed in the conveyance direction, while the work is fitted along a part of the peeling roller142and is conveyed in a direction different from the conveyance direction of the unnecessary parts Mb. Thus, the unnecessary parts Mb of the metal sheet are separated from the work having the continuous bodies “C” and “M.” The unnecessary parts Mb that are collected are subjected to a reprocessing process and are reused as the continuous body “M” of the metal sheet.

The pressurizing process P5is executed by a pressurizing unit150. The pressurizing unit150includes a pressing roller151and a support roller152. The pressurizing unit150pressurizes the work while nipping and conveying it between the pressing roller151and the support roller152, to spread the adhesive “A” over the entire surfaces of the antennas3placed on the continuous body “C.” The degree of pressure is preferably 2 kg/cm or greater and 6 kg/cm or less.

After the pressurizing process P5is performed, the work having the antennas3placed on the continuous body “C” is wound up by a winding roller102.

The antenna forming process including the processes P1to P5described above enables forming the antennas3on the continuous body “C” of the thermal paper2.

In the pressurizing process P5of the antenna forming process, the pressurizing unit150pressurizes the work while nipping it between the pressing roller151and the support roller152, to spread the adhesive “A” over the entire surfaces of the antennas3placed on the continuous body “C.” In addition, pressurizing causes adhesion of the adhesive “A,” whereby the antenna3is closely attached to the continuous body “C.”

In the pressurizing process P5, when the work, which has the antennas3placed on the continuous body “C,” is pressurized by the pressing roller151and the support roller152while being conveyed, the adhesive “A” that is placed between the continuous body “C” and the antenna3is drawn to the upstream side in the conveyance direction. In consideration of this, in the method for manufacturing the antenna pattern of this embodiment, the placement position of adhesive “A” is arranged so that the margin on the upstream side in the conveyance direction will be wider than the margin on the downstream side in the conveyance direction between the outer circumferential line of the antenna3and the adhesive “A” placed inside thereof. As a result, the adhesive “A” that is drawn to the upstream side in the conveyance direction remains within the margin “mu,” which is set wide on the upstream side in the conveyance direction.

In the antenna forming process, the adhesive “A” does not adhere to the unnecessary parts Mb of the metal sheet, and therefore, a winding roller for the unnecessary parts Mb (not shown inFIG.3) does not need to be applied with a peeling force for peeling the unnecessary parts Mb from the work, in winding up the unnecessary parts Mb. This enables setting a conveying speed of the work without having to consider factors such as the peeling force of the unnecessary parts Mb of the metal sheet and breakage due to the peeling force. In addition, the unnecessary parts Mb of the metal sheet, which do not have the adhesive “A” and other foreign substances due to adhesion of the adhesive “A,” has good handleability after being collected and also provides excellent reusability of the metal sheet.

In the removal process P4of the antenna forming process, in addition to the peeling rollers141and142that separate the work and the unnecessary parts Mb of the metal sheet from each other, a suction mechanism for sucking to remove the unnecessary parts Mb may also be provided. This configuration reliably removes metal sheet pieces that tend to be left on the work only by separation using the peeling rollers141and142.

Although not illustrated, after the antenna forming process, an adhesion-facilitating process, an ACP ejecting process, an IC chip placement process, and an ACP curing process are performed in this order.

The adhesion-facilitating process is a process for emitting laser to an IC chip placement surface of the antenna to roughen the surface.

In the ACP ejecting process, ACP is ejected from a dispenser to a predetermined position of each antenna3, which is formed on the continuous body “C” of the thermal paper in the antenna forming process.

In the IC chip placement process, the IC chip4is placed by pressing it against the ACP, which is disposed on the antenna3in the ACP ejecting process.

In the ACP curing process, the ACP on the antenna3is irradiated with ultraviolet light to be cured while the IC chip4placed on the antenna3is pressed by a pressing unit. An ultraviolet light irradiator may be integrated with the pressing unit or may be disposed on an oblique upper side so as to emit ultraviolet light to the ACP from an oblique upward direction. An LED lamp that generates less heat is suitable for the ultraviolet light irradiator.

The ACP ejecting process, the IC chip placement process, and the ACP curing process cause the antenna3and the IC chip4to stick and electrically connect together.

Next, the substrate21on which the antenna3and the IC chip4have been stacked, is applied with the adhesive-for-adherend6, on the entire surface, and it is then temporarily attached to the separator7. Thus, the RFID label1in the state shown inFIG.1is completed. Alternatively, the separator7may be applied with an adhesive on a release layer side surface and may be bonded to the substrate21, including the antenna3and the IC chip4. Thereafter, the completed RFID label1is punched into a desired shape.

The RFID label1, which is manufactured as described above, has the antenna3and the IC chip4that are directly placed on the surface opposite to the surface provided with the thermosensitive color developing layer22, of the thermal paper2. This structure enables to omit a base film of an inlay, resulting in reduction in the amount of constituent materials and contribution to resource saving. In this RFID label1, the antenna3and the IC chip4are bonded together by emitting ultraviolet light to the ACP. That is, unlike a conventional bonding method using a thermosetting adhesive, heat is not applied in bonding the antenna3and the IC chip4together, whereby the thermal paper2in the vicinity of the IC chip4is not discolored. Thus, the RFID label1can be used in a wide application in printing the thermal paper2by a thermal printer.

FIG.5shows an RFID label10of another embodiment.FIG.5illustrates a cross section of the RFID label10in the same manner as inFIG.2.

The RFID label10uses a double-sided adhesive tape16instead of the adhesive-for-adherend6of the RFID label1, which is already described with reference toFIG.2. The double-sided adhesive tape16is composed of an adhesive layer26a, a core material25made of paper or film, and an adhesive layer26bthat are stacked in this order. A tape roll (not shown) of the double-sided adhesive tape16has a separator that is temporarily attached to each of the adhesive layers26aand26b. The separator on the adhesive layer26ais peeled from the tape roll, and the exposed adhesive layer26ais laminated on a surface on the antenna3side of the thermal paper2, whereby the cross sectional structure shown inFIG.5is obtained. In this case, the separator of the double-sided adhesive tape may be used as a separator17, as it is, or it may be exchanged for another separator suitable for a label.

In addition, it is also possible to use a tape roll of a double-sided adhesive tape16that is wound by using a double-sided release coated separator that has a release agent layer on each side of a substrate. A lamination body of the double-sided adhesive tape16and the double-sided release coated separator may be laminated on a surface on the antenna side of the thermal paper2.

The cross sectional structure inFIG.5imparts cushioning characteristics due to the core material25, which is effective to protect the IC chip4.

The double-sided adhesive tape may be one that does not have a core material. In this case, the cross sectional structure as shown inFIG.2is obtained. The separator of the double-sided adhesive tape may be used as the separator17, as it is, or it may be exchanged for a separator suitable for a label roll in laminating.

(3) RFID Recording Medium

An RFID recording medium of one embodiment includes an outside base material that is placed on the adhesive-for-adherend6of the RFID label1, instead of the separator7.

The RFID recording medium can be used as, for example, a tag, a card, a wrist band, or a ticket, and the outer shapes of the thermal paper2and the outside base material are determined depending on the application of the RFID recording medium.

A method for manufacturing the RFID recording medium can be the same as the above-described method for manufacturing the RFID label, except that the outside base material is attached to the adhesive-for-adherend6, instead of the separator7.

Although embodiments of the RFID label, the RFID recording medium, and the method for manufacturing the RFID label are described above, the present invention should not be limited to the foregoing embodiments. In addition, the embodiments described above can be variously modified and altered within the scope not departing from the gist of the present invention.

The present invention is related to Japanese Patent Application No. 2021-13411 filed with the Japan Patent Office on Jan. 29, 2021, the entire contents of which are incorporated into this specification by reference.