DE10259965A1 - Heat activated adhesive film for the implantation of electrical modules in a telephone card, identity card or bank card comprises a vinyl aromatic block copolymer and a resin that is compatible with the terminal blocks - Google Patents

Abstract

Heat-activated adhesive film for implanting electrical modules in a card body, which is provided with a recess into which an electrical module is to be arranged, which has a plurality of contact surfaces on the first side and an IC component on the second side opposite the first side, the connection points of which are connected to the contact areas via electrical conductors, the adhesive film being used to connect the second side of the module to the card body, characterized in that DOLLAR A the adhesive film contains at least the following components: DOLLAR A i) one or more vinylaromatic block copolymers with a total proportion of 20% by weight to 75% by weight, preferably 30% by weight to 70% by weight, particularly preferably from 40% by weight to 60% by weight of the adhesive; DOLLAR A ii) one or more resins compatible with end blocks with a proportion of 25% by weight to 70% by weight.

Description

The invention relates to an adhesive film for gluing electrical modules in a card body.

The following is the bonded composite from an electrical module and card body as a smart card or smart Card called.

Data carrier with integrated circuit have been for a long time known and very widespread, for example as calling cards, Identification cards, bank cards or the like. For implantation of the support elements for the Chips modules called - in the appropriately dimensioned hollows of the card body different adhesive systems used. However, cannot all conceivable adhesive systems are used because of the requirements the adhesive bond are very high. So the bond strength be very big because only a very small adhesive area is available. The modules are allowed but must not come loose from the card even when it is bent. Furthermore is currently being implanted with cycle times of approximately one second worked.

Two-component adhesive systems are for this reason not suitable due to their slow hardening. on the other hand can also no solvent adhesives be used because the solvent could attack the cards.

Instead today liquid Cyanoacrylate-based adhesives used at room temperature harden quickly. However, since this process is catalyzed by water, the curing speed is heavily from the humidity during depending on the implantation.

When using liquid adhesives it can easily lead to production disruptions for example through untargeted hardening and the consequent Clogging of the nozzles come. Also comes it easy to squeeze the adhesive out of the glue line or on the so-called blooming effect, in which cyanoacrylate vapors locally affect the card surface dye irreversible matt white.

Heat-activated ones also come Adhesive films for use. These adhesive films are made at elevated temperature laminated on a module belt, then the laminate is punched, to get individual modules. This process is easier feasible if the adhesive films do not have their own tack at room temperature own, otherwise they can stick to the punch.

Mainly come, such as in EP 0 842 995 B1 and in DE 44 27 802 C1 described, for these heat-activated films thermoplastics are used, some of which are mixed with different resins. Often these are reactive resins. The disadvantage of these films is that they need a high temperature in order to become sticky. The implantation must take place at a temperature of at least 120 ° C, whereby the hot stamp used has a significantly higher temperature - 50 ° C to 70 ° C higher. With such a temperature load, the plastics of some cards are mainly damaged from PVC, PET or ABS, which may have a negative impact on later use. The bond strength of these adhesive films based on thermoplastic materials generally increases with the implant temperature, so that considerably higher temperatures are required for very good bonding.

• i) ein thermoplastisches Polymer mit einem Anteil von 30 bis 89,9 Gew.-%,
• ii) ein oder mehrere klebrigmachende Harze mit einem Anteil von 5 bis 50 Gew.-% und/oder
• iii) Epoxydharze mit Härtern, gegebenenfalls auch Beschleunigern, mit einem Anteil von 5 bis 40 Gew.-%,
• iv) versilberte Glaskugeln oder Silberpartikel mit einem Anteil von 0,1 bis 40 Gew.-%.

The prior art further discloses in WO 00/01782 A1 an electrically conductive, thermoplastic and heat-activatable adhesive film containing

• i) a thermoplastic polymer in a proportion of 30 to 89.9% by weight,
• ii) one or more tackifying resins in a proportion of 5 to 50% by weight and / or
• iii) epoxy resins with hardeners, optionally also accelerators, in a proportion of 5 to 40% by weight,
• iv) silver-plated glass balls or silver particles with a proportion of 0.1 to 40 wt .-%.

A further development is from the DE 198 53 805 A1 became known with the electrically conductive, thermoplastic and heat-activated adhesive film that contains

• i) a thermoplastic polymer with a Proportion of at least 30% by weight,
• ii) one or more tackifying resins with a proportion from 5 to 50% by weight and / or
• iii) epoxy resins with hardeners, optionally also accelerators, with a proportion of 5 to 40% by weight,
• iv) metallized particles with a proportion of 0.1 to 40% by weight,
• v) difficult or non-deformable spacer particles with a Proportion of 1 to 10% by weight at the bonding temperature Do not melt the adhesive film.

According to preferred embodiments the thermoplastic polymers are thermoplastic Polyolefins, polyesters, polyurethanes or polyamides or modified Rubbers, such as, in particular, nitrile rubbers.

Object of the present invention is to develop a heat-activated adhesive film that lower temperature can be implanted, but similarly high Bonding strength, like the adhesive films, has so far are used.

This task is solved by an adhesive film, as in the main claim is marked. Developments of the adhesive film according to the invention are the subject of the subclaims.

• i) eines oder mehrere Vinylaromatenblockcopolymere, wobei der Gesamtanteil der Vinylaromatenblockcopolymere an der Klebmasse beträgt 20 Gew.-% bis 75 Gew.-%, bevorzugt 30 Gew.-% bis 70 Gew.-%, besonders bevorzugt 40 Gew.-% bis 60 Gew.-%, und
• ii) eines oder mehrere endblockverträgliche Harze mit einem Anteil von 25 Gew.-% bis 70 Gew.-%.

Accordingly, the invention relates to a heat-activated adhesive film for implanting electrical modules in a card body, which is provided with a recess into which an electrical module is to be arranged, which has a plurality of contact surfaces on the first side and an IC on the second side opposite the first side. Has module whose connection points are connected to the contact areas via electrical conductors, the adhesive film being used to connect the second side of the module to the card body, the adhesive film containing at least the following components:

• i) one or more vinylaromatic block copolymers, the total proportion of the vinylaromatic block copolymers in the adhesive being 20% by weight to 75% by weight, preferably 30% by weight to 70% by weight, particularly preferably 40% by weight to 60 % By weight, and
• ii) one or more resins compatible with end blocks with a proportion of 25% by weight to 70% by weight.

It is preferably the vinyl aromatic block copolymers are styrene block copolymers which again in a particularly advantageous embodiment of the invention Are styrene-butadiene or styrene-isoprene block copolymers.

In a further advantageous embodiment According to the invention, the adhesive film has a thickness of 20 to 500 μm.

Thermoplastic elastomers, especially those based on block copolymers are an elastomeric component for adhesives known. Especially in the manufacture of pressure sensitive adhesives they use. Vinyl aromatic block copolymers, preferably styrene block copolymers, possess due to their block structure and the phase separation implied thereby the soft and hard phases have a very high cohesion. They also own also a high elasticity, like you for the applications in module bonding is necessary.

Styrene block copolymers are alone not sticky and can not be made sticky even by thermal activation. A stickiness comes only through the addition of different low molecular weight Resins.

There are two types of Resins differentiated, on the one hand the medium block compatible Resins that are more compatible with the middle block than with the styrene end blocks, and Those that are better or only compatible with the end blocks. While in pressure sensitive adhesives the medium block compatible resins for the stickiness worry and the endblock compatible Resins mainly for Increase in cohesion and the improved thermal stability could be surprisingly found that in heat-activated systems the end block compatible Resins for a stickiness at elevated As a result, temperatures result in a very high bonding performance. The bond strengths can through skillful selection of the resins those of the thermoplastic Achieve systems. The ease of processing is advantageous both from solution as well as from the melt.

Because a large selection of end block compatible Resins with different softening points are available, the temperature at which the modules need to be implanted can be very simple can be set. This means that implant temperatures are also possible are significantly lower than those of previous adhesive films be used so that deformations of the card body prevented can be.

adhesives

Such adhesives are preferred formed on the basis of block copolymers containing polymer blocks of vinyl aromatics (A blocks), preferably styrene, and those formed by polymerization of 1,3-serving (B blocks), preferably butadiene and isoprene, use. Both homo- and copolymer blocks are usable according to the invention. resulting Block copolymers can contain the same or different B blocks, some of which are selective or completely can be hydrogenated. Block copolymers can have linear A-B-A structure. Block copolymers can also be used of radial shape as well as star-shaped and linear multiblock copolymers. A-B two-block copolymers can be used as further components to be available. Block copolymers of vinyl aromatics and isobutylene can also be used according to the invention. All of the the aforementioned polymers can can be used alone or in a mixture. Particularly advantageous have block copolymers with a block polystyrene content of 20 up to 30% by weight.

Instead of polystyrene blocks, polymer blocks can also be used Basis of other aromatic-containing homo- and copolymers (preferably C8- up to C12 aromatics) with glass transition temperatures of> approx. 75 ° C such as α-methylstyrene-containing Aromatics. They are also polymer blocks based on (meth) acrylate homo- and (meth) acrylate copolymers with Glass transition temperatures usable from> +75 ° C. Here you can both block copolymers are used, which as hard blocks are only such based on (meth) acrylate polymers as well as those which both polyaromatic blocks, for example polystyrene blocks, as well as poly (meth) acrylate blocks use.

Instead of styrene-butadiene block copoly mers and styrene-isoprene block copolymers and their hydrogenation products, consequently styrene-ethylene / butylene block copolymers and styrene-ethylene / propylene block copolymers, can also be used according to the invention block copolymers and their hydrogenation products which use further polydiene-containing elastomer blocks, such as copolymers of several different ones 1,3-diene. Functionalized block copolymers, such as, for example, maleic anhydride-modified or silane-modified vinylaromatic block copolymers, can also be used according to the invention.

Typical use concentrations for the vinyl aromatic block copolymers are in the range between 20 wt.% and 75 wt.%, preferably in Range between 30 wt .-% and 70 wt .-%, particularly preferably in Range between 40% and 60% by weight.

Such can be used as further polymers based on pure hydrocarbons, for example unsaturated polydienes, like natural or synthetic polyisoprene or polybutadiene, chemical essentially saturated Elastomers such as saturated Ethylene-propylene copolymers, α-olefin copolymers, Polyisobutylene, butyl rubber, ethylene propylene rubber and chemically functionalized hydrocarbons, such as halogen-containing, acrylate-containing or vinyl ether-containing polyolefins are used, which up to a proportion of up to 100 phr based on the vinyl aromatic block copolymer may be present.

Adhesive films according to the invention are used as tackifiers as the main component in particular resins that are with the vinyl aromatic end block the vinyl aromatic block copolymers are compatible.

Among others, preferred are Resins based on pure aromatics, such as alpha-methylstyrene, Vinyl toluene or styrene, or resins from mixtures of different aromatic Monomers.

Coumarone indene resins can also be used, which are obtained from coal tar. Another class Resins that can be used are low molecular weight polyphenylene oxides particularly well tolerated are with styrene end blocks.

Typically used as further additives become primary Antioxidants, such as sterically hindered phenols, secondary antioxidants, such as phosphites or thioethers, process stabilizers, such as C radical scavengers, Light stabilizers, such as UV absorbers or sterically hindered Amines, antiozonants, metal deactivators and processing aids, to name just a few.

Plasticizers, such as plasticizing oils or low molecular weight liquid Polymers, such as low molecular weight polyisobutylenes Molar masses <1500 g / mol (number average), or liquid EPDM types are typically used in small amounts of <10% by weight.

fillers, such as silicon dioxide, glass (ground or in the form of Spheres), aluminum oxides, zinc oxides, calcium carbonates, calcium sulfates, Titanium dioxide, carbon black and color pigments, to name a few, can also be used.

Furthermore, the adhesive film in particular Balls with a metallic, i.e. conductive, coating (e.g. gold or silver) added be or metal-containing particles. The particles can be made of pure metal (gold, Silver) can exist but also be made of an alloy that then becomes one significant proportion of the metal should be included for conductivity sure.

If in the following from the metallized balls (preferably made of glass), the expert knows that this mentioned Always read particles.

The diameter of the glass balls is in an advantageous embodiment the invention at least equal to the thickness of the adhesive film but also something about the thickness of the adhesive film to be produced.

In an alternative advantageous embodiment the adhesive film, the diameter of the glass spheres is between 10 μm and 20 μm smaller than the thickness of the adhesive film.

What diameter of the glass balls is chosen according to the invention, depends on the intended use of the adhesive film.

If the diameter of the glass balls above the thickness of the adhesive film can be from the adhesive film outstanding glass balls to undesirable air pockets in the glue line, what the connection strength can degrade. Under unfavorable Conditions this can cause that the glass balls in an elastic adhesive joint with mechanical Loads lose contact, which is only possible by pressing again can be restored.

Therefore, in some applications the connection strength versus of conductivity in the foreground. This must be done at high pressure and at elevated temperature be glued. In this particular case, the adhesive film can be used outstanding, electrically conductive Glass balls are dispensed with.

The conductive glass balls can then about 10 to 20 μm be smaller than the thickness of the adhesive film and thus a light one Tack and full area Gluing without air pockets enable.

The electrical contact is nevertheless made, since under these bonding conditions the viscosity of the adhesive is reduced so much that it is displaced and the thickness of the adhesive joint is reduced. This happens, for example, when gluing modules in smart cards. Under the usual conditions, the conductive glass balls get an electrically conductive contact because the adhesive is displaced and into a cavity under the Dodge chip module.

The contained in the adhesive film preferably soft conductive Particles in particular have a conductivity in the z direction. Then comes in the x-y plane because of the lack of contact with each other no conductivity conditions.

The softness of the particles causes that the particles flatten out at the contact surfaces with the substrates, what the contact area elevated, and that they can adapt to mechanical stress.

To avoid excessive deformation of the To prevent adhesive film, it can be beneficial to use spacer particles to be mixed, in a proportion of 1 to 10 wt .-%. The Spacer particles are in particular of spherical geometry and exist made of a hard material that at the elevated bonding temperature does not melt and is difficult or not deformable. The spacer particles can also conductive be, but they should be harder be than the metallized particles. Furthermore, they should be one have a smaller diameter than the conductive particles.

The thickness of the spacer particles corresponds such as the one desired after pressing or bonding Thickness of the adhesive layer. So they have a diameter the slightly smaller is than the thickness of the adhesive film. They allow an exact setting this thickness through the bonding process under temperature, pressure and the plane parallelism the pressure stamp, even if these bonding parameters fluctuate. The mentioned Spacers are preferably spherical hard particles such as Example glass balls. A metal layer on these balls is possible, however not necessary because the additional, if any, additional ones metallized particles have sufficient conductivity cause and thus a conductive system already exists.

The adhesive film according to the invention can be particularly advantageous are used to implant electrical modules in a Card body, which is provided with a recess into which an electronic To be arranged module that on the first page several contact surfaces and on the opposite side of the first page second side has an IC chip, the connection points via electrical Conductor with the contact areas are connected, the adhesive film for connecting the second Side of the module with the card body is used.

Preferably in this case the adhesive film has the same dimensions as the module and lies as Die cut before.

By the choice according to the invention of the input materials can Adhesive films are produced with a very high bond strength especially on the polar map materials.

The polystyrene content of the Block copolymers on the amount of endblock compatible Resins are matched. When using block copolymer and resins compatible with end blocks in relation to A polystyrene content of 20 to 25% by weight of 1: 1 has proven ideal proved. When using copolymers with higher styrene contents, the extensibility of the adhesive masses reduced, so that it can possibly loosen the bond under extreme conditions Bending can come. When using these elastomers, the content should on endblock compatible Resins are reduced.

By the choice according to the invention the end block compatible Resins can change the softening temperature and thus the suitable implantation temperature can be set flexibly. End block amplifier resins with a higher softening point than the polystyrene of the block copolymers, ie above 110 ° C, increase the softening point of the Adhesive, compatible with end blocks Resins with softening points below 100 ° C reduce it instead.

However, the softening point of the adhesive becomes chosen too low, can Adhesives are created that have a certain pressure-sensitive tack at room temperature show what they are not used with the currently common process can be because the punchability is limited is. Moreover the bond strength at elevated temperatures is then limited.

On the other hand, the softening points of the Resins not chosen too high because otherwise the temperature required to implant the modules is so high that the card body can be deformed when pressing the modules with a hot stamp.

One was particularly suitable Mixture of an end block amplifier resin with a softening point well above 110 ° C and a resin with a softening point below 100 ° C proved. Adhesives on this basis can be used at low Implant temperatures, but are sufficiently high Adhesion resistance even at 40 ° C, as used in warm countries occur as well as a sufficient Elasticity to does not come off when the card bends.

Some examples of adhesive films according to the invention are described below, without wishing to restrict the invention in any way. Example 1: 50% by weight Finapren 401 40% by weight Kristallex 1120 10% by weight Piccotex 75

The feedstocks are in toluene solved and in a layer thickness of 70 μm streaked. Subsequently the adhesive film obtained is laminated onto a module belt at 130 ° C, individual modules punched out and at 150 ° C stamp temperature, which is one Temperature of approx. 100 ° C in the adhesive joint, with a hot stamp in a milled PVC card implanted.

The card is subjected to an ISO bending test subjected.

After 3000 bends there are no signs of peeling to recognize the modules from the chip cards.

Example 2

The same raw materials as described above are compounded in a kneader from Werner and Pfleiderer and subsequently with the help of a hot press to 70 μm pressed. The compacts are handled in exactly the same way as with the solvent adhesive is described above.

Also with this pattern are after 3000 bends no signs of peeling to recognize.

Claims (11)

Heat-activated adhesive film for implanting electrical modules in a card body, which is provided with a recess into which an electrical module is to be arranged, which has a plurality of contact surfaces on the first side and an IC component on the second side opposite the first side, the connection points of which are connected to the contact surfaces via electrical conductors, the adhesive film serving to connect the second side of the module to the card body, characterized in that the adhesive film contains at least the following constituents: i) one or more vinylaromatic block copolymers with a total proportion of 20% by weight % to 75% by weight, preferably 30% by weight to 70% by weight, particularly preferably from 40% by weight to 60% by weight of the adhesive; ii) one or more resins compatible with end blocks with a proportion of 25% by weight to 70% by weight. Adhesive film according to claim 1, characterized in that the vinyl aromatic block copolymers are styrene block copolymers is. Adhesive film according to claim 2, characterized in that the styrene block copolymers are styrene-butadiene or styrene-isoprene block copolymers is. Adhesive film according to at least one of claims 1 to 3, characterized in that the adhesive film with one or several additives such as anti-aging agents, UV protective agents, dyes, mineral or organic fillers is mixed. Adhesive film according to at least one of claims 1 to 4, characterized in that the adhesive film still more Contains polymers like pure hydrocarbons, for example unsaturated polydienes, natural or synthetic polyisoprene or polybutadiene, chemical essentially saturated Elastomers such as saturated Ethylene-propylene copolymers, α-olefin copolymers, Polyisobutylene, butyl rubber, ethylene propylene rubber and chemically functionalized hydrocarbons, such as halogen-containing, acrylate-containing or vinyl ether-containing polyolefins. Adhesive film according to at least one of claims 1 to 5, characterized in that the end block compatible Resins from the group of aromatic hydrocarbon resins, coumarone indene resins or polyphenylene oxides. Adhesive film according to at least one of claims 1 to 6, characterized in that the adhesive film is at least one resin compatible with end blocks with a higher one Softening point than the polyvinyl aromatic block and at least one endblockverträgliches Resin with a lower softening point than the polyvinyl aromatic block has Adhesive film according to at least one of claims 1 to 7, characterized in that the adhesive film has a thickness of 20 to 500 μm having. Adhesive film according to at least one of claims 1 to 8, characterized in that the adhesive film for hot pressing at temperatures below 120 ° C suitable is. Adhesive film according to at least one of claims 1 to 9, characterized in that the adhesive film is the same Has dimensions as the module and as a die cut. Use of a heat-activated adhesive film according to one of claims 1 to 10 for implanting electrical modules in a card body which is provided with a recess into which an electrical module is to be arranged, which has a plurality of contact surfaces on the first side and on the second side opposite the first side Side has an IC chip, the connection points ver via electrical conductors with the contact surfaces are bound, the adhesive film being used to connect the second side of the module to the card body.