JP2002528907A - Hot melt adhesive component layers for smart cards - Google Patents

Abstract

  (57) [Summary] The present invention relates to the use of thermoplastic hot melt adhesives for producing component layers in smart cards or for producing electronic responders by low pressure injection molding processes at pressures ranging from 1 to 50 bar. Preferably, hot melt adhesives based on polyamides, polyurethanes, polyesters, atactic polypropylene, EVA copolymers or low molecular weight ethylene copolymers or mixtures thereof are used in this method.

Description

DETAILED DESCRIPTION OF THE INVENTION

TECHNICAL FIELD [0001] The present invention relates to multilayer composites, methods of making the composites, and the use of thermoplastic hot melt adhesives to make the composites.

BACKGROUND OF THE INVENTION [0002] The present invention relates primarily, but not exclusively, to the manufacture of objects known as smart cards. A smart card is a generally multi-layered article in the form of a plastic card, which typically has information and / or advertising imprints and / or features for protection, such as a photo of the cardholder, magnetic Articles provided with strips, identification symbols (in the form of holograms), etc. are provided. The smart card usually consists of a plastic card laminated on one or both sides. Embedded in the body of this smart card is what is known as a module, an important component of which is an electronic circuit (chip). The chip can be mounted on a support plate, which in one particular embodiment is provided with a plurality of conductive surface segments. Since the segmented electrical contact areas are accessible from the outside, information, for example data and identification features, can be exchanged by contacting them with external computers and / or controls.

[0003] Newer types of cards include an antenna electrically coupled to a chip within the card body, which provides a contactless energy supply to the chip within the card body and a contactless information transfer. Both electronic exchanges have become easier. These types of smart cards include telephone cards, authorization cards for mobile communication devices,
Used or intended as a check card in money processing, proof of permit from a health insurance organization, a driver's license, train tickets and bus tickets. The user inserts the contactless smart card into the card reader or moves it a certain distance past the reader, which communicates with the electronics in the smart card via a corresponding antenna arrangement. In this way, for example, in the case of a telephone card or a check card or a train ticket, it is possible to check the existence of a savings, to verify the identity or to carry out some other data exchange .

[0004] Methods for producing contactless smart cards are basically known. For example, International Patent Application Publication WO 98/09252 describes a multi-step manufacturing method. In this method, a so-called component layer or card body is provided with openings, depressions or similar cavities, after which the electronic components to be arranged in the card body are inserted into these cavities, The card body is then coated with an adhesive so that the cavities are filled and the adhesive forms a substantially flat surface. Then, a cover film is applied to the surface of the adhesive. This adhesive is uncured or not completely cured and can therefore still be plastically deformed. The surface of the cover film away from the card body is then fixedly maintained on the shaped surface and the outer contour of the cover film (i.e., the outer contour of the final smart card) is maintained for a sufficient time during the curing of the adhesive. , To match the contour of the shaped surface. Proposed adhesives are cold-setting adhesives, especially epoxy adhesives. To prevent the adhesive from shrinking, it must be filled with a filling material such as glass, quartz or the like. This manufacturing method involves many working steps, is time consuming,
Therefore, it is very expensive.

[0005] EP-A-0692770 discloses that at appropriate times during a number of working steps, a chip and an antenna are introduced into the cavity of an injection mold, after which a thermoplastic material is introduced into the mold. The method of injection is described. Proposed thermoplastic materials are conventional injection molding materials, for example, PVC, ABS (terpolymer of acrylonitrile-butadiene-styrene), polyethylene terephthalate (PET), polycarbonate (PC) or polyamide (PA). is there. Such injection molding materials require very high temperatures and high pressures during processing (eg, a pressure of 700 kg / cm ² ). However, such high pressures and temperatures are very unsuitable for sensitive electronic circuits to be embedded, and as a result, these circuits are more likely to be damaged.

[0006] EP-A-0 709 804 discloses a multi-stage injection molding process,
It has been proposed to first insert a plastic disc into an injection mold and place the antenna on the disc. Next, a liquid polymer material (specifically, A
Spread BS, PC, PET, polyamide, or a reactive resin that cures at relatively high temperatures, such as polyurethane, epoxy-phenolic resin) over the surface of this antenna, leaving the antenna connection exposed. . Then, a plastic film sealing the hole in the card is placed on the antenna. The plastic film has a recess in which an electronic chip is provided so as to make electrical contact with the antenna contact. This method also requires high temperatures and high pressures in the injection molding process, and additional work to insert the electrical circuit into the card body, secure it, and electrically connect it to the antenna Requires a process.

Japanese Patent Application Publication JP-A-08276459 is a method for manufacturing a contactless smart card, wherein a component support is made of an epoxy resin reinforced with glass fiber, which has a depression. , Optionally including conductor lines (including those for forming antennas). The electronic chip is introduced into the recess of the component layer. The entire component is then inserted into an injection mold and, after closing the mold, the liquid thermoset polymer material is injected at low pressure into the mold and cured therein. Specifically, a thermosetting epoxy resin has been proposed for this purpose. The curing of the epoxy resin takes 4-5 minutes. After the molded article has been removed from the mold, post-curing by heating at a certain temperature for a certain time is necessary (specific details of this post-curing are not described).

[0008] EP-A-0350179 describes a method for producing smart cards and similar electronic articles by the reaction injection molding method. The electronic circuit is encapsulated by a layer formed by the reaction injection molding material. The cover films on both sides of the card are fed into the mold during the injection molding process so that they also act as release agents to facilitate removal of the cured card body from the injection mold. No specific details regarding the composition of the polymer for the reaction injection molding process are given,
It is only mentioned that any polymer material or any polymer mixture that cures under reaction injection molding conditions can be employed. Due to the exact metering equipment required, reaction injection molding machines are known to be expensive and complex.

[0009] EP-A-0846743 describes a thermoplastic, thermosetting self-adhesive sheet for embedding an electrical module in a card body. The card body is provided with a cutout in which the electronic module is intended to be arranged, which module has a plurality of contact areas on the first side, On the side face, there is an IC chip (the contacts of which are connected to the contact area by electrical leads). The adhesive sheet comprises a thermoplastic polymer, one or more tackifying resins and / or epoxy resins (optionally a curing agent,
And an accelerator. These adhesive sheets must be heat cured at about 150 ° C. for 30 minutes.

[0010] JP-A-05270173 describes a method for producing a laminated sheet-like polymer structure for a blank card body. For this purpose, two rigid PVC sheets are coated with a film of a 5-50 μm thick moisture-curable polyurethane hot melt adhesive at 100-120 ° C.
Compress under pressure of g / cm ² for 10 seconds. One of these sheets has a cutout or a cavity prepared by thermoforming, which is intended to be compatible with a subsequently inserted microprocessor. Thereafter, these sheet-like structures are left for several hours at room temperature without pressure to cure the adhesive and obtain the card base material. This base material can be processed into the final smart card in a further processing step.

DISCLOSURE OF THE INVENTION Accordingly, it is an object of the present invention to develop a gentle, fast and easy method for smart card production that allows for cost-effective large-scale production of such smart cards. Was to do.

[0012] The achievement of this object according to the present invention is set forth in the appended claims. It is essentially the use of thermoplastic hot melt adhesives to make the component layers of smart cards, and the use of thermoplastic hot melt adhesives at low temperatures and low pressures in low pressure injection molding processes. And a method for manufacturing the smart card.

BEST MODE FOR CARRYING OUT THE INVENTION As a thermoplastic hot melt adhesive, a low-melting polyamide based on polyaminoamide, thermoplastic polyurethane or atactic polypropylene or a mixture thereof is used for producing a component layer. It is preferably used. These thermoplastic hot melt adhesives are characterized by low viscosities at processing temperatures of about 100 to 100,000 mPa · s. As a result, they can be used in low-pressure injection molding processes at pressures of 1 to 50 bar, preferably of 10 to 30 bar. The processing temperature depends on the composition of the hot melt adhesive material, but it is between 80 and 25
0 ° C., preferably in the range of 100 to 230 ° C. The polyamides preferably used usually have a viscosity at 210 ° C. of less than 10,000 mPa · s. 2
A particularly preferred range of the processing viscosity at 10 ° C. is in the range of 1,500 to 4,000 mPa · s. This viscosity is usually measured using an RVD with Thermocel equipment.
It is measured using a Brookfield viscometer of type VII.

In certain cases, a reactive moisture-postcrosslinkable polyurethane hot melt adhesive can be used in place of the thermoplastic hot melt adhesive described above. This moisture-reactive polyurethane hot melt adhesive requires great care during application due to its sensitivity to moisture, but has the advantage of being at a significantly lower viscosity at processing temperatures. Generally, reactive polyurethane hot melt adhesives are:
A viscosity of <25,000 mPa · s at 130 ° C., preferably 15,000 mP
a.s or less, very preferably 10,000 mP at 130 ° C.
It has a viscosity of not more than a · s. This viscosity is usually determined by the RVD with thermocell equipment.
It is measured using a Brookfield viscometer of type VII. The advantage of using a moisture-curable polyurethane hot melt adhesive is its low melting point, which is usually below 100 ° C., preferably below 70-80 ° C., making it a very temperature sensitive circuit. Can be embedded using these hot melt adhesives, and even a laminated film which is extremely sensitive to temperature can be used. These post-crosslinking by moisture results in the formation of particularly resistant and temperature-stable bonds between the component layers and the base and cover films.

[0015] The use of a thermoplastic hot melt adhesive to produce the component layers eliminates the need for subsequent milling to create the space required to fit the chip or chip and antenna. The reason for this is that these components to be encapsulated can be placed in a corresponding encapsulation mold before finishing the base structure. In a later encapsulation process, the chip or the chip and the antenna are surrounded by the base body (component support) thus produced, so that any additional fixing or cushioning or surrounding filling of the electronic components is no longer necessary. It will not be needed later. Furthermore, when applying a printable or printed base film and cover film, it can be preceded by an additional application of an adhesive to the component support. The reason for this is that the latter, of course, is produced from an adhesive and forms a strong bond with the base film and / or cover film after being appropriately activated by optional heating.

According to the present invention, in a low pressure injection molding method, 80 to 250 ° C., preferably 100 ° C.
If it can be processed at a temperature of ２３０230 ° C., that is, the processing viscosity is 100 to 10
If within the range of 0.000 mPa · s, all thermoplastic reactive and non-reactive hot melt adhesives can be used to make the card base. The pressure range for the low-pressure injection molding process is in the range from 1 to 50 bar, with the range for injection molding from 10 to 30 bar being particularly preferred. This means that the inserted chip or other electronic storage medium used can be gently surrounded, and
Ensure that they are not destroyed or damaged as in normal injection molding processes with high injection pressures (500-> 1,000 bar).

Depending on the nature of the base and cover films used in the final card, and on the rigidity and elasticity requirements of the card body and the possible temperature stress thereto, hot melt adhesives , Polyamides (particularly polyamideamides based on dimerized fatty acids), polyurethanes, polyesters, ethylene-vinyl acetate (EVA) copolymers, low molecular weight polyethylene copolymers, atactic polypropylene (APP) or combinations thereof. You can choose. As already mentioned above, in certain cases it may be advantageous to use a reactive hot-melt adhesive based on moisture-postcrosslinkable polyurethane instead of the thermoplastic hot-melt adhesive described above.

As base film and / or cover film, it is possible here to use all films which are known in principle for this purpose. Examples which may be mentioned include films based on polyesters, especially polyethylene terephthalate (PET), polyvinyl chloride (PVC), acrylonitrile-butadiene-styrene (ABS), polycarbonate (PC) or polyimide. These films usually have a thickness of up to 100 μm, and preferably have a film thickness of 30 to 7
It is within the range of 0 μm.

In the manufacturing method of the present invention, various procedures can be adopted. First,
The chip and the associated antenna can first be placed where appropriate in the injection mold of the injection molding machine. The chip and antenna can be in a form pre-assembled on a support film, for example. After closing the mold, the hot melt adhesive is injected. After a short cooling, the mold can be opened and the component layer thus produced can be removed from the mold. Since the matrix of the layers of the card body itself acts as an adhesive, no further application of the adhesive is necessary for subsequent lamination with the base film and / or the cover film. All that is required is to compress the film and component layers, optionally with heating.

According to an alternative, a thin film of hot melt adhesive can be placed in an injection mold, on which electronic components and antennas can be placed. The mold is then closed and the electronic components are completely encapsulated by injection of another hot melt adhesive material. In this case, too, the film can be compressed with the component layers, optionally with heating, and the film can be permanently bonded to this layer, so that it can be laminated to a base film and / or cover film. No further application of adhesive is necessary. The film thickness of the hot melt adhesive matrix containing the encapsulated chips is currently usually 400-600 μm, preferably 500 μm, but can be thinner or thicker depending on the type of chip. .

In one particularly preferred embodiment, for the embedding of the electronic components and the antenna in the matrix of a card support layer comprising a hot melt adhesive, from Optimel Schmelzgusstechnik Low pressure processing systems can be used. FIG. 1 shows a preferred embodiment of the injection mold.
3 to FIG.

According to FIG. 1, the lower part 1 of the injection mold has a cutout 2 whose length and width correspond to the dimensions of the upper part of the injection mold. The lower part of the injection mold also has runners 3 so that the hot melt adhesive can fill the entire mold completely without bubbles in a very short cycle time. Designed. Further, the shape of the runner is designed so that the sprue remaining on the card body after the card body has solidified can be easily removed.

FIG. 2 is a cross-sectional view of the upper portion 4 of the injection mold, which crosses the line AB in FIG. In the upper end region, the upper part has a projection 5, so that when this upper part is aligned with the cutout 2 of the lower part, a completely sealed chamber is formed in the injection mold. It is formed. The cutout 6 of the upper part 4 corresponds in its length and width dimensions to the card carrier layer to be manufactured. The thickness of the cutout 6 corresponds to the thickness of the component layer to be manufactured.

FIG. 3 is a detailed view of FIG. 2C, showing the cutout 6 of the card support layer in detail.

In the continuous manufacturing method, the base film and the cover layer film are simultaneously formed with the chip and, if desired, the antenna (optionally, may be applied in a copper foil on a thin flexible film) and an injection mold. Can be supplied to After closing the mold, the hot melt adhesive is again injected. After brief cooling and opening of the mold, the finished layer body can be transported further. This procedure offers the advantage that the base layer and the cover layer can be used simultaneously as release agents in the injection mold. In all of the manufacturing methods described above, features for normal information and / or advertising imprinting and / or protection, such as photographs of cardholders, magnetic strips, identification symbols (in the form of holograms), etc. Can be provided to a base film and / or a cover film in an upstream or downstream manufacturing process.

The advantages of using a thermoplastic hot-melt adhesive to produce a component layer according to the present invention, as compared to the prior art, are as follows: No support material has to be produced; no milling work is required to produce cutouts for chips and antennas; also independent adhesive bonding of chips and antennas to cutouts Not necessary; after lamination with a base film and a cover film, on the one hand, since the card carrier layer has a very smooth surface and, on the other hand, itself acts as an adhesive, resulting from normal production There is no "read-through" of unevenness.

(Industrial Applicability) The main field of application of the present invention is in the field of the production of contactless cards (smart cards) comprising electronic circuits. It can also be used to produce responders in mechanical engineering as well as in building containers for operational control.

[Brief description of the drawings]

FIG. 1 is a plan view of a lower portion of an injection mold.

FIG. 2 is a side view of an upper part of an injection mold.

FIG. 3 is a detailed view of an upper part.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H01L 23/02 G06K 19/00 K // B29L 31:34 H (72) Inventor Paul Lanft Germany Day 40724 Hilden, Rodenheide 34 (72) Inventor Jurgen Grutzner Federal Republic of Germany Day-47259 Deusbruck, Bitburger Strasse 35 A No. (72) Inventor Uwe Kolp Federal Republic of Germany Day-71111 Vogtlandstrasse No. 16 F term (reference) 4F206 AA07 AA11 AA19 AA24 AA29 AA31 AD05 AD08 AH37 JA07 JB17 4J040 DA011 DA051 DA101 DE031 EF001 EG001 JB01 LA01 MA10 MB03 NA21 5B035 BA05 BB09 CA01 CA23

Claims (6)

[Claims] 1. Use of a thermoplastic hot-melt adhesive for producing a component layer of a smart card. 2. Use of a thermoplastic hot melt adhesive to produce a responder. 3. The hot melt adhesive is made of polyamide, polyurethane, polyester, atactic polypropylene (APP), ethylene-vinyl acetate (EVA).
3. Use according to claim 1 or 2, having a composition based on a copolymer, a low molecular weight polyethylene copolymer or a mixture thereof. 4. A method for manufacturing a card body (smart card) including an electronic circuit, wherein a processing viscosity is set to 100 to 100,000 mPa · s (Brookfield, RVDV II + thermocell) as a material of a constituent layer. Using a thermoplastic hot melt adhesive. 5. The composition layer is formed at a temperature of 80 to 250 ° C., preferably 100 to 230 ° C.
The method according to claim 4, wherein the molding is carried out by a low-pressure injection molding method at a processing temperature of 1C and a pressure of 1 to 50 bar. 6. A multilayer card body in which a layer holding an electronic circuit is made of a thermoplastic hot melt adhesive.