JP4239760B2 - Multilayer sheet - Google Patents

Description

  The present invention relates to a multilayer sheet optimal for the production of IC cards and the like.

  As a substitute for a conventional magnetic card in a credit card, cash card, prepaid card, etc., an IC card equipped with an IC module having a large recording capacity and excellent security has been developed.

  There are two types of IC cards, contact type and non-contact type, depending on how the recording medium is read. In the contact type, the card and reader come into contact with each other when communicating with the terminal. There is a drawback that it is easy to get dirty or broken. Also, man-hours are required for leader maintenance. On the other hand, in the non-contact method, since the recording medium and the reader do not have a contact point, these drawbacks including the maintenance work of the reader are improved, but the security system is not perfect and is still widely deployed. However, some non-contact type IC cards have begun to be put into practical use, such as commuter passes.

  As a method for manufacturing these IC cards, conventionally, a method has been used in which an embedding space of an IC module is counterbored or an embedding space is secured by sandwiching a spacer, and an oversheet is laminated / heat pressed on the embedding space. Has been taken. However, the counterbore processing to the base sheet has a problem that the number of manufacturing steps and the cost are increased. Even in the method of providing the embedded space with the spacer, the alignment of the spacer and the shape processing thereof are necessary, and therefore the process is complicated.

  In Patent Document 1, a card is proposed by an injection molding machine. This is a method in which a base for fixing an IC module is formed by an injection molding method, and the IC module is placed and fixed on the base, and then injection molded again to form a card. However, this method is not preferable in terms of production efficiency because it requires two injection molding steps to make a card. Further, the module may be broken or the completed card may be warped due to heat or pressure at the time of injection molding, which may not be appropriate in the manufacture of an IC card.

  Patent Document 2 discloses an IC card in which a base material layer on which an IC module is mounted, a hot melt resin, and an oversheet are sequentially laminated. It is a method of embedding an IC module by prescribing and processing the viscosity of the hot melt resin, laminating the oversheet and hot pressing, but in order to embed the IC module, it is usually more than the thickness of the IC chip. If it is not formed thick, the card surface will not be flat. In general, since the thickness needs to be several tens to several hundreds of microns, the coating method requires repeated processing, and there is a problem of requiring a great number of man-hours.

  Patent Document 3 discloses a method of embedding an IC module by providing a polymer layer for flow / embedding such as an IC chip having a softening point lower than these softening points between two plastic sheets. According to the invention, in consideration of the thickness of various modules such as an IC chip bonded on a substrate, a polymer layer at least about 1.1 times the thickness of the IC chip or the like is required. Since the layer is required to be thick, the flow of the polymer layer becomes large and oozes out, which may contaminate the hot platen for pressing, resulting in poor production efficiency.

  In addition, financial cards that are being developed include not only built-in IC chips for security reasons, but also those that are read by a contact reader / writer that also uses magnetic stripes that have been widely used in the past. There is something. Furthermore, a thermal rewritable recording medium is sometimes applied to the card surface, and the demand for surface smoothness of the IC card is increasing.

  In order to solve these problems, for example, a laminated sheet is obtained by coating or superposing an adhesive resin on one surface of a plastic sheet and hot pressing, and a substrate on which various IC modules are arranged is sandwiched and heated. In this method, a plastic sheet or an adhesive resin is a material having high adhesiveness even at room temperature because of its thermal characteristics such as melting point and glass transition temperature. For example, when the obtained laminated sheet is rolled, or stacked as a cut plate with a certain size, the work efficiency may be impaired due to blocking or poor sliding.

  As a method for solving this, Patent Document 4 discloses an invention characterized in that a release film is provided on at least one surface of a laminated sheet composed of a plastic film / adhesive layer. In the invention, the laminated sheet is formed by a known coating process or extrusion coating on a plastic film that has already been formed, and further, a polyester film or a release material that has already been formed is also applied and processed. Paper is applied as a release film, but it is necessary to repeat the extrusion process several times in order to obtain a laminated sheet, and the process tends to be complicated.

  Under these circumstances, development of a multilayer sheet that can be suitably used as an intermediate base material layer that enables adhesion of an oversheet having a special printing function and the like while eliminating unevenness caused by the IC module of the base material layer has been developed. Not done.

JP-A-3-24000 JP-A-10-147087 JP 11-338990 A Japanese Patent Laid-Open No. 11-328340

  The present invention is to solve the above problems. That is, the present invention prevents the warp and sink of the finished IC card, is excellent in handling at the time of production without causing blocking, and has a core in which the outermost layer (overlay) constituting the card is bonded to the IC module. To provide a multilayer sheet that can be suitably used as a material for heat-sealing a layer to be used, and can realize surface smoothness that can be suitably used for an IC card or the like regardless of contact type or non-contact type. is there.

The present invention
(1) An adhesive layer having a softening point temperature measured by a predetermined method of the resin defined by JIS K2531 in the range of 120 ° C. to 150 ° C. and a thickness in the range of 5 to 100 μm on both surfaces of the plastic film. A multilayer sheet characterized by further comprising a release resin layer on at least one surface of the adhesive layer,
(2) The multilayer sheet according to (1), which is used as a process sheet for IC card production,
It is.

  According to the present invention, since the resin of the adhesive layer is melted and fluidized and flows around the IC chip or the like to fill the irregularities, a smooth and curl-free IC card can be produced. When an IC card is produced using the multilayer sheet having the release resin layer of the present invention, the multilayer sheet can be continuously run without blocking between the multilayer sheets, and can be laminated with good surface smoothness. In addition, the greatest feature of the present invention is that a plastic film can be selected as appropriate because adhesive layers are provided on both sides of the plastic film of the multilayer sheet. As a result, heat resistance, rigidity, bending resistance, transparency, etc. can be selected and imparted according to the usage characteristics of the IC card, and the thickness of the adhesive is optimal for the substrate or surface layer to which the IC module is bonded. Since the adjustment can be made according to the value, the protrusion of the adhesive material generated during pressing can be reduced, so that there is little dirt on the press plate and the IC card can be produced efficiently.

  The multilayer sheet for an IC card of the present invention is composed of at least four layers of a plastic film, an adhesive layer applied to both sides thereof, and a release resin layer. The adhesive layer is provided on both surfaces of the plastic film, and the adhesive layer has a softening point temperature measured by the method defined in JIS K2531 in the range of 120 ° C. to 150 ° C., and is adhered to an adherend such as a plastic film by heat melting. It has adhesive performance. The release resin layer is provided on at least one surface of the adhesive layer.

  In the present invention, the plastic film is not particularly limited as long as it has sufficient mechanical properties and processability when actually used as an IC card. For example, polyethylene terephthalate (PET) or polybutylene terephthalate (PBT), polyethylene naphthalate (PEN), polycarbonate (PC), polyetherimide (PEI), polyimide (PI), polyethersulfone (PES), polyphenylene sulfide (PPS) ), A film produced from polyether ether ketone (PEEK) or the like, and these copolymers and blends may be used depending on the purpose of use.

  In the present invention, the thickness of the plastic film is not particularly limited, but considering the total thickness of a general card, for example, it is preferably 50 to 500 μm.

In the present invention, the adhesive layer in which the IC chip or the like is embedded is not particularly limited as long as it is a resin that is heated and melted to exhibit adhesion performance to the adherend, but polyolefin resin, polyester resin, polyurethane resin Or it is preferable that it is a vinyl acetate type resin, and it is more preferable that the softening point temperature measured by the predetermined | prescribed method of the said resin prescribed | regulated to JISK2531 exists in the range of 120 to 150 degreeC.
If the softening point temperature is lower than 120 ° C, when producing an IC card, there is a risk of blocking of the adhesive layer, and if the actual set temperature of the hot platen is set higher, the viscosity will decrease due to a decrease in viscosity. Unloading may occur, which may cause dirt on a hot plate for pressing, etc., which is not preferable. On the other hand, when the softening point temperature exceeds 150 ° C., it is necessary to set the heat fusion temperature higher, and it is not preferable because the resin cannot be sufficiently wrapped when the IC chip is embedded.
Here, the polyester resin may be amorphous or crystalline. For example, when the resin layer used as a base material is a polyester film, a copolyester resin, a polyurethane resin, a modified polyethylene resin, etc. are preferable, and the resin layer used as a base material is a PVC system such as PVC or chlorinated PVC. In the case of a film, it is preferable to use a vinyl acetate resin or the like. Further, a thermosetting resin may be formulated for the purpose of increasing the adhesive strength. For example, an epoxy-based thermosetting resin can be suitably formulated.

  In the present invention, the thickness of the adhesive layer is not particularly defined as long as the IC chip or the like is sufficiently embedded by heat fusion so that the unevenness of the surface can be eliminated. 5 to 100 μm can be more suitably used. However, if the thickness is less than 5 μm, the IC chip or the like cannot be embedded well, the step cannot be eliminated, and the surface smoothness cannot be obtained. If it is thinner than 100μ, the flow of the adhesive becomes large, and the hot platen or the like is soiled with the adhesive.

  In the present invention, the resin used for the release resin layer is not particularly limited as long as it has a release function with respect to a plastic film or an adhesive layer. For example, polyolefin resins such as polyethylene and polypropylene can be preferably used. .

  In the present invention, the thickness of the release resin layer is not particularly limited and is appropriately determined depending on the storage method and the like. For example, in the case of storing in a roll, the thinner is preferable, and in the case of stacking and storing, it is considered preferable to have a certain thickness. When the release resin layer is disposed on either side of the adhesive layer applied to both sides of the plastic film, the thickness of the release resin layer may be the same or different on both sides.

  When producing an IC card using a multilayer sheet in which a release resin layer is laminated on the adhesive layer of the present invention, the release resin layer is removed immediately before the multilayer sheet is bonded, and then an IC chip or the like is sandwiched between the adhesive layer surfaces. Then, by heating from the outer plastic film side, the resin of the adhesive layer is fluidized to embed an IC module or the like and perform heat fusion. Even when the multilayer sheet is wound and stored in a roll shape and unwound for bonding, the release resin layer is continuously peeled off from the multilayer sheet immediately before bonding. When the sheet is cut into a predetermined size and used as a single sheet, the release resin layer may be peeled off immediately before bonding or may be peeled off in advance.

  The IC chip or the like may be arranged directly on the adhesive layer surface of the multilayer sheet of the present invention. However, the IC chip or the like is preliminarily wired to a plastic sheet that becomes the core material of the IC card, and this is used as the IC card multilayer sheet of the present invention. Good smoothness can be obtained by using and sandwiching between the adhesive layers.

  In addition, there are cases in which an IC card is manufactured by a method of continuously manufacturing a multi-layer sheet wound in a roll shape, or a manufacturing method of cutting a sheet into a specific size and supplying it in a single sheet. According to this method, mass production is possible, so that productivity is good, and the production of IC cards by this method is increasing. When a multi-layer sheet is wound into a roll shape or a sheet that has been cut into a specific size is stacked, the laminated sheets that are not provided with a release film cause blocking between the laminated sheets, which makes handling difficult. However, as in the present invention, if a release resin layer having a release function is provided on the adhesive layer, even if the multilayer sheet is wound into a roll shape, or how many sheets are cut into a specific size Even if they are overlapped, blocking does not occur because the bonding surface of the adhesive layer does not directly contact the substrate.

Each layer of the multilayer sheet of the present invention is desirably laminated by a known coextrusion method. For the coextrusion method, known techniques such as a casting method and an inflation method can be used. By laminating each resin layer by the co-extrusion method, the thickness of each layer can be set arbitrarily as compared with other methods such as a coating method, so that it can be more easily produced.

<Example 1>
A polyester resin having a thickness of 20 μm having a softening point measured by a predetermined method of a resin defined by JIS K2531 as a bonding layer is laminated on both surfaces of a copolymerized polyethylene terephthalate resin layer having a thickness of 100 μm and further bonded. A multilayer sheet was prepared by laminating a polyethylene resin having a thickness of 50 μm as a release resin layer on the resin layer by a known coextrusion method.

  An oversheet is placed on one side of the obtained multilayer sheet, and a base material layer bonded with an IC module is bonded to the other side to produce an IC card. The layers were peeled and bonded together with the adhesive layers facing each other. However, the base sheet is wired with a loop coil for a 5-turn antenna in which a copper wire having a wire diameter of 0.20 mm is wound six times, or an IC chip having a size of 5 mm × 5 mm and a thickness of 0.23 mm. The laminated sheet was continuously laminated with a multilayer sheet and a laminator at a bonding temperature of 120 ° C., a bonding pressure of 8.5 kg / cm 2 and a bonding speed of 0.5 m / min. Next, the bonded film was cut and punched to obtain an IC card in which an antenna loop coil and an IC chip were embedded.

  About the obtained IC card, the surface smoothness of the embedded part of the IC chip was visually determined. As a result, it was found that none of the obtained IC cards was curled and showed good surface smoothness.

  In addition, instead of using the antenna loop coil, IC chip, etc. arranged on the plastic sheet, an IC card in which the IC chip etc. is directly arranged on the multilayer sheet of Example 1 was also created. Good surface smoothness was exhibited.

Moreover, the obtained multilayer sheet was wound and stored in a roll shape, and bonded in the same manner as described above using this roll. The multi-layer sheet is unwound from the roll-shaped scroll, and the release resin layer is peeled off and bonded immediately before bonding, so that the multi-layer sheets do not block each other and the multi-layer sheet runs normally and the IC card is It was possible to produce continuously and efficiently. When the surface smoothness of the obtained IC card was judged visually, it showed good surface smoothness.
<Example 2>

  As the adhesive layer, a plastic film having a thickness of 250 μm was used in the same manner as in Example 1 except that a 90 μm-thick polyurethane resin having a softening point temperature of 148 ° C. measured by a predetermined method of the resin defined by JIS K2531 was used. A multilayer sheet was prepared by laminating a polycarbonate resin and a 50 μm-thick polypropylene resin on both sides of the adhesive layer as a release resin layer. Next, using the obtained multilayer sheet, an IC card was produced in the same manner as in Example 1.

For the obtained IC card, the surface smoothness of the embedded portion of the IC chip was visually determined in the same manner as in Example 1. As a result, it was found that none of the obtained IC cards was curled and showed good surface smoothness. As in Example 1, an IC card in which an IC chip or the like was directly placed on a multilayer sheet and bonded was also produced, and good surface smoothness was exhibited.
<Example 3>

  As the adhesive layer, a plastic film of 470 μm was used in the same manner as in Example 1 except that a polypropylene resin having a softening point temperature of 120 ° C. and a thickness of 50 μm measured by a predetermined method of the resin defined by JIS K2531 was used. A multilayer sheet in which a polybutylene terephthalate resin and a 75 μm thick polyethylene resin as a release resin layer were laminated on both sides of the adhesive layer was prepared. Next, using the obtained sheet-like multilayer sheet, an IC card was produced in the same manner as in Example 1.

  For the obtained IC card, the surface smoothness of the embedded portion of the IC chip was visually determined in the same manner as in Example 1. As a result, it was found that none of the obtained IC cards was curled and showed good surface smoothness. As in Example 1, an IC card in which an IC chip or the like was directly placed on a multilayer sheet and bonded was also produced, and good surface smoothness was exhibited.

Moreover, when an IC card was produced using two rolls of a multilayer sheet wound in a roll shape in the same manner as in Example 1, blocking did not occur as in Example 1, and normal running was performed. The obtained IC card was excellent in surface smoothness.
<Comparative Example 1>

A multilayer IC card as in Example 1, except that a polyester resin having a softening point temperature of 155 ° C. and a thickness of 20 μm measured by a predetermined method of resin defined by JIS K2531 was laminated on both sides as an adhesive layer. A sheet was produced. Using the obtained multilayer sheet, an IC chip or the like was embedded in the same manner as in Example 1, and an attempt was made to continuously bond the IC card with a laminator. However, since the obtained multilayer sheet had a high softening point temperature, the adhesive resin layer could not be embedded well and the smoothness of the card surface could not be obtained.
<Comparative example 2>

A multilayer sheet for an IC card was produced in the same manner as in Example 2 except that the release layer resin was not laminated. An attempt was made to embed an IC module or the like in the same manner as in Example 2 using the obtained sheet-like multilayer sheet so that the adhesive layers face each other and to continuously bond the IC cards with a laminator. However, since the release resin layer was not provided in the obtained multilayer sheet, the multilayer sheets were blocked from each other, and the film did not travel normally, and the multilayer sheets could not be bonded continuously.
<Comparative Example 3>

A multilayer sheet for an IC card was produced in the same manner as in Example 2 except that the thickness of the adhesive layer was 2 μm. Using the obtained sheet-like multilayer sheet, an IC chip or the like was embedded in the same manner as in Example 3, and an attempt was made to continuously bond the IC card with a laminator. However, since the thickness of the adhesive layer of the obtained multilayer sheet was thin, the adhesive layer could not be embedded well, and the smoothness of the card surface could not be obtained.

  As an intermediate material for bonding a substrate having surface irregularities and a surface layer having a specific function, it can also be applied to applications where surface smoothness is indispensable. For example, when adhering automobile interior materials and steel plates, or when adhering laminated lining sheets, the adhesive sheet alone is not rigid, and it is inferior in handling due to blocking, so the multilayer sheet of the present invention Can be suitably used.

Claims (2)

On both surfaces of the plastic film is in the range of 0.99 ° C. predetermined softening temperature assuming by way from 120 ° C. of the resin defined by JIS K2531, and have a bonding layer having a thickness in the range of 5～100Myu m and further wherein a multi-layer sheet that have a release resin layer on at least one surface of the adhesive layer, the adhesive layer is a polyolefin resin, a polyester resin, either in a polyurethane resin or vinyl acetate resin Multi-layer sheet composed.



  The multilayer sheet according to claim 1, which is used as a process sheet in IC card production.