EP1699890A1

EP1699890A1 - Hot-melt adhesive

Info

Publication number: EP1699890A1
Application number: EP04804964A
Authority: EP
Inventors: Marc Husemann; Renke Bargmann
Original assignee: Tesa SE
Current assignee: Tesa SE
Priority date: 2003-12-23
Filing date: 2004-12-21
Publication date: 2006-09-13
Also published as: DE112004002195D2; WO2005063907A1; DE10361538A1; MXPA06007084A; US20080026186A1

Abstract

The invention relates to an adhesive film consisting of a thermoplastic and optionally one or more resins. According to the invention: a) the adhesive system has a softening temperature that is greater than 65 °C and less than 125 °C; b) a melt-flow index (ISO 1133) that is greater than 3 and less than 100 cm3/10 minutes; c) a storage modulus G', measured according to test method A, at 23 °C that is greater than 107 Pas; d) a loss modulus G'', measured according to test method A, at 23 °C that is greater than 106 Pas; e) and a crossover, measured according to test method A, of less than 125 °C.

Description

description

MELTING GLUE

The invention relates to a thermoplastic hotmelt adhesive, optionally with reactive resin, which is activated at implant temperatures of 150 ° C. and is used for bonding electrical modules to card bodies.

A large number of adhesive films or joining methods are already known in the prior art for implanting electrical modules in card bodies. The aim of these implants is the production of telephone cards, credit cards, automatic parking cards, insurance cards, etc. Examples of the corresponding bonding processes can be found e.g. in the patents EP 0842 995 A, EP 1 078965 A and DE 19948 560 A.

In this area of bonding, however, the requirements for the adhesive system are increasing continuously. The adhesive must have good adhesion to polycarbonate, ABS, PVC and PET, but also good adhesion to the electrical module. As a rule, gluing is carried out on epoxy materials, polyesters or polyimides. In the past, cyan acrylates were used as liquid adhesives, which had the advantage that optimal wetting of the card body and the electrical chip was achieved. However, this technology is dying out because the processes are very slow. The solvent evaporated only slowly from the cavity of the card body, the syringes for dosing clogged when they stopped due to drying out and were also difficult to dose, and the liquid adhesive also needed a certain amount of time to harden. As a result, the quality of the bond was quite poor.

Here the hotmelt pressure sensitive adhesives are clearly superior to the liquid adhesives. Nevertheless, the selection of suitable connections is also very limited here, since very high demands are placed on this joining technology. They are very limited different materials that have to be glued. Due to the very different polarities of PC, PVC, PET, ABS, epoxy and polyimide, it is impossible to find a single polymer that adheres equally well to all materials. The requirements of end customers continue to increase. For example, the flatness of the electrical module with the card body is an important criterion, since otherwise the cards could no longer be read out. This means that there is an upper limit on the implant temperatures, since PVC in particular, for example, tends to deform at implant temperatures above 170 ° C. Another criterion is the requirement from the banking sector that the electrical modules cannot be removed without being destroyed. Accordingly, the internal cohesion of the adhesive must be very high, so that it does not split in the middle and the adhesion on both sides (card body + electrical module) is extremely high. At the same time, the adhesive must also have a very high level of flexibility, since the cards undergo torsion and bending tests after the implantation. The card material should preferably break before the adhesion to the card body and to the electrical module ceases. As a rule, not even marginal withdrawals are tolerated. Another criterion are temperature fluctuations and the influence of moisture, since these cards withstand both high and low temperatures in later use and sometimes have to survive one wash cycle. Accordingly, the adhesive should not become brittle at low temperatures, should not liquefy at high temperatures and have a low tendency to absorb water.

Another requirement criterion is the processing speed due to the growing number of card requirements. The adhesive should soften or melt very quickly so that the implantation process can be completed within a second.

In view of this prior art, the invention is based on the object of specifying an adhesive film for implanting electrical modules in a card body, which fulfills the criteria mentioned above and in particular at implant temperatures of 150 ° C. in the stamp for the different card bodies and electrical modules trains very high liability.

According to the invention the object is achieved by an adhesive film consisting of a thermoplastic and optionally one or more resins, the adhesive system a) has a softening temperature greater than 65 ° C and less than 125 ° C b) a melt flow index of greater than 3 and less than 100 cm ³ / has 10 minutes (measured according to the ISO 1133 at T = 150 ° C at 2.16 kg) c) has a memory module G 'measured at 23 ° C of greater than 10 ⁷ Pas according to test method A d) has a loss module G "measured at 23 ° C of greater than 10 ⁶ Pas e) and a crossover measured according to test method A ( Identity of memory module and loss module) of less than 125 ° C.

The theological properties of the temperature-activated adhesive system have optimized flow behavior.

Furthermore, the crossover temperature must be below 125 ° C, otherwise the adhesive would not flow and would therefore not optimally wet the card surface and the electrical module. At the crossover point, the curves of the storage module G 'and loss module G "intersect; physically this should be interpreted as a transition from elastic to viscous behavior.

Furthermore, the elastic component, that is, the storage module G ', must be greater than 10 ⁷ Pas and the viscous component, that is, the loss modulus G ", must be greater than 10 ⁶ Pas, since otherwise no optimal flexibility of the adhesive is guaranteed. The adhesive must between occurring loads card body and electrical module ensure even under strong deformations. Therefore, a Theologically optimized viskoeiastisches behavior is required. the melt flow index should be between 3 and 50 cm ^3/10 minutes. at a value of less than 3 cm ^3/10 minutes, the card surface is not sufficiently wetted . at levels of greater than 50 cm ^3/10 minutes for the implantation, the adhesive is squeezed out.

The bonding of the electrical module 2 to a card body 3 is shown schematically in FIG. 1). The inventive temperature-activatable adhesive 1 has a layer thickness between 10 and 100 μm in a preferred embodiment, and a layer thickness of 30 to 80 μm in a particularly preferred embodiment. Heat activated glue

The heat-activatable adhesive serves in particular as an adhesive film for gluing electrical chip modules in card bodies, the respective adhesive layer forming very good adhesion to the card body and to the electrical chip module after the temperature activation.

The heat-activatable adhesive has good adhesion to epoxy materials, polyesters and polyimides for bonding the electrical module and good adhesion to PC, ABS, PVC and PET for bonding to card bodies. In a very preferred design, thermoplastic materials are used for this, e.g. Polyurethanes, polyesters, polyamides, ethylene vinyl acetates, synthetic rubbers, such as e.g. Styrenoprene di- and triblock copolymers (SIS), styrene-butadiene di- and triblock copolymers (SBS), styrene-ethylene-butadiene di- and triblock copolymers (SEBS), polyvinyl acetate, polyimides, polyethers, copolyamides, copolyesters, polyolefins, e.g. Polyethylene, polypropylene, or poly (meth) acrylates. The list does not claim to be complete.

The polymers have a softening range between 65 and 125 °.

Resins or reactive resins that increase the adhesive strength can be added to optimize the adhesive properties and the activation range. The proportion of the resins is between 2 and 50% by weight, based on the thermoplastic.

All of the previously known adhesive resins described in the literature can be used as tackifying resins to be added. Representative are the pinene, indene and rosin resins, their disproportionated, hydrogenated, polymerized, esterified derivatives and salts, the aliphatic and aromatic hydrocarbon resins, terpene resins and terpene-phenolic resins as well as C5, C9 and other hydrocarbon resins. Any combination of these and other resins can be used to adjust the properties of the resulting adhesive as desired. In general, all (soluble) resins compatible with the corresponding thermoplastic can be used, in particular reference is made to all aliphatic, aromatic, alkylaromatic hydrocarbon resins, hydrocarbon resins based on pure monomers, hydrogenated hydrocarbon resins, functional hydrocarbon resins and natural resins. Attention is drawn to the presentation of the state of knowledge in the "Handbook of Pressure Sensitive Adhesive Technology" by Donatas Satas (van Nostrand, 1989). In a further preferred embodiment, reactive resins are added to the heat-activatable adhesive.

A very preferred group includes epoxy resins. The molecular weight M _w (weight average) of the epoxy resins varies from 100 g / mol up to a maximum of 10000 g / mol for polymeric epoxy resins.

The epoxy resins include, for example, the reaction product of bisphenol A and epichlorohydrin, the reaction product of phenol and formaldehyde (novolak resins) and epichlorohydrin, glycidyl ester, the reaction product of epichlorohydrin and p-amino phenol.

Preferred commercial examples are e.g. Araldite ™ 6010, CY-281 ™, ECN ™ 1273, ECN ™ 1280, MY 720, RD-2 from Ciba Geigy, DER ™ 331, DER ™ 732, DER ™ 736, DEN ™ 432, DEN ™ 438, DEN ™ 485 from Dow Chemical, Epon ™ 812, 825, 826, 828, 830, 834, 836, 871, 872, 1001, 1004, 1031 etc. from Shell Chemical and HPT ™ 1071, HPT ™ 1079 also from Shell Chemical.

Examples of commercial aliphatic epoxy resins are e.g. Vinyl cyclohexane dioxides such as ERL-4206, ERL-4221, ERL 4201, ERL-4289 or ERL-0400 from Union Carbide Corp.

As novolak resins e.g. Epi-Rez ™ 5132 from Celanese, ESCN-001 from Sumitomo Chemical, CY-281 from Ciba Geigy, DEN ™ 431, DEN ™ 438, Quatrex 5010 from Dow Chemical, RE 305S from Nippon Kayaku, Epicion ™ N673 from DaiNipon Ink Chemistry or Epicote ™ 152 from Shell Chemical.

Melamine resins, such as e.g. Cymel ™ 327 and 323 from Cytec.

Terpenophenol resins such as NIREZ ™ 2019 from Arizona Chemical can also be used as reactive resins. Phenolic resins such as YP 50 from Toto Kasei, PKHC from Union Carbide Corp. can also be used as reactive resins. and BKR 2620 from Showa Union Gosei Corp. deploy.

Furthermore, polyisocyanates such as e.g. Use Coronate ™ L from Nippon Polyurethane Ind., Desmodur ™ N3300 or Mondur ™ 489 from Bayer.

In order to accelerate the reaction between the two components, crosslinkers and accelerators can optionally be added to the mixture.

Suitable accelerators are e.g. Imidazoles, commercially available from 2M7, 2E4MN, 2PZ-CN, 2PZ-CNS, P0505, L07N from Shikoku Chem. Corp. or Curezol 2MZ from Air Products.

Furthermore, amines, especially tertiary amines, can also be used for acceleration.

In addition to reactive resins, plasticizers can also be used. In a preferred embodiment of the invention, plasticizers based on polyglycol ethers, polyethylene oxides, phosphate esters, aliphatic carboxylic acid esters and benzoic acid esters can be used here. Aromatic carboxylic acid esters, higher molecular weight diols, sulfonamides and adipic acid esters can also be used.

Furthermore, fillers (e.g. fibers, carbon black, zinc oxide, titanium dioxide, chalk, solid or hollow glass spheres, microspheres made of other materials, silica, silicates), nucleating agents, blowing agents, compounding agents and / or anti-aging agents, e.g. in the form of primary and secondary antioxidants or in the form of light stabilizers.

In a further preferred embodiment of the pressure-sensitive adhesive tape according to the invention, polyolefins, in particular poly-α-olefins, are used in the sense of layer i), which have a softening range of greater than 65 ° C. and less than 125 ° C. and also reappear after cooling while cooling solidify. Of the Degussa are commercially available under the trade name Vestoplast ™ different heat-activatable poly-α-olefins.

In a preferred embodiment, the polyolefin-activatable adhesives have static softening temperatures T _E , _A or melting points T _{S, A} of 65 ° C. to 125 ° C. The adhesive strength of these polymers can be increased by targeted additives. For example, polyimine or polyvinyl acetate copolymers can be used as additives that promote adhesion.

Manufacturing process

The heat-activatable adhesive must be made available for further processing for the bonding of electrical modules on card bodies on a release paper or a release liner. The coating can be done from solution or - very preferably - from the melt. For the application from the melt - if the polymer is in solution - the solvent is preferably drawn off in a concentration extruder under reduced pressure, for which purpose, for example, single- or twin-screw extruders can be used, which preferably distill off the solvent in different or the same vacuum stages and via feed preheating feature. Coating is then carried out via a melt nozzle or an extrusion nozzle, the adhesive film possibly being stretched in order to achieve the optimum coating thickness. A kneader or a twin-screw extruder can be used to mix the resins.

The carrier materials for the adhesive are the materials which are familiar and customary to the person skilled in the art, such as foils (polyester, PET, PE, PP, BOPP, PVC, polyimide), nonwovens, foams, woven and woven foils and release paper (glassine, HDPE, LDPE). The carrier materials should be equipped with a separating layer. In a very preferred embodiment of the invention, the separating layer consists of a silicone separating lacquer or a fluorinated separating lacquer. Examples

Test Methods:

Rheology A)

The measurement was carried out using a rheometer from Rheometrics Dynamic Systems (RDA II).

The "Rheomatics Dynamical Analyzer" (RDA II) measures the torque that occurs when an oscillating shear is applied to a strip specimen (deformation control).

The sample diameter was 8 mm, the sample thickness was between 1 and 2 mm. It was measured with the plate-on-plate configuration (parallel plates). The temperature sweep from 0 to 150 ° C was recorded at a frequency of 10 rad / s.

Iso-Bending B)

The iso-bending test is carried out analogously to the ISO / IEC standard 10373: 1993 (E) - section 6.1. The test is passed if a total of more than 4000 bends are reached.

Extreme bending test C)

In the extreme bending test, a 3 cm wide cut-out with the electrical module lying in the middle is cut out of the chip card and then pressed 10 times from 3 cm wide to 2.5 cm wide. The test is passed if the electrical module does not come out.

Hand test D)

In the hand test, the chip card is bent by hand over one of the two corners, which are closer to the electrical module, until the card breaks or the module breaks. Then the test is passed. If the electrical module comes loose or pops out, the test is considered failed.

MFIE)

The Meltflow Index MFI was carried out according to ISO 1133 (Procedure B, volume-flow-rate MVR). The test was carried out at 150 ° C at 2.16 kg. Other test methods

Molecular weight determinations were carried out using GPC measurements (gel permeation chromatography). (Preparation of a solution of the sample in tetrahydrofuran with a concentration of 3 g / l; dissolving process for 12 hours at room temperature; then filtration of the solution through a 1 μm disposable filter, addition of approx. 200 ppm toluene as an internal standard.

Using an autosampler, 20μl of the solution is chromatographed as follows: After a 10 ³ Ä column of 50 mm in length, a 10 ⁶ Ä, a 10 ⁴ Ä and a 10 Ä column each with a length of 300mm follow. Tetrahydrofuran is used as the eluent and is pumped at a flow rate of 1.0 ml / min. The columns are calibrated with polystyrene standards, the detection is carried out by measuring the change in the refractive index using a Shodex differential refractometer Rl 71).

The softening temperatures are preferably determined using differential scanning calorimetry (DSC).

investigations:

Reference 1)

Polyamide film XAF 34.408 from Collano-Xiro

Reference 2)

PU film XAF 36.304 from Collano Xiro

Example 1)

Griltex 9 E (copolyester) from EMS-Grilltech + 25% by weight EPR 0191 (epoxy resin, bisphenol A resin with a softening range of 60 ° C.) from Bakelite were mixed in a measuring kneader from Haake at approx. 130 ° C and 15 minutes at 25 rpm. mixed. The heat-activatable adhesive was then pressed to 60 μm at 140 ° C. between two layers of siliconized glassine release paper. By test method E) of the MFI was 30 cm ^3/10 minutes. Example 2)

Griltex 9 E (copolyester) from EMS-Grilltech was pressed between two layers of siliconized glassine release paper to 60 μm at 140 ° C. By test method E) was the MF1 18 cm ^3/10 minutes.

Example 3

Platamid 2395 (copolyamide) from Atofina + 20% by weight EPR 0191 (epoxy resin, bisphenol resin with a softening range of 60 ° C.) from Bakelite were mixed in one

Measuring kneader from Haake at approx. 130 ° C and 15 minutes at 25 rpm. mixed. The

Heat-activatable adhesive was then siliconized between two layers

Glassine release paper pressed to 60 μm at 140 ° C.

By test method E) of 16 cm ³ was MF1 / 10 minutes.

Implantation of the electrical modules

The implantation of the electrical modules in the card body was carried out with an implanter from Ruhlamat. The following materials were used.

Electrical modules: Nedcard Dummy N4C-25C, tape type: 0232-10 PVC cards: CCD ABS card: ORGA

In a first step, examples 1 to 3 are laminated at 2 bar onto the module belt from Nedcard using a two-roll laminating system from Storck GmbH. Then the electrical modules are implanted in the appropriate cavity of the card body. The following parameters were used for all examples:

Heating steps: 1

Stamp temperature: 150 ° C time: 1 x 2 s cooling step: 1x 800 ms, 25 ° C pressure: 70 N per module Results:

The chip cards produced with the inventive adhesives were tested using test methods B, C and D. The results are shown in Table 1.

Tab. 1

Table 1 shows that all inventive examples have passed the most important criteria for a chip card and are therefore very well suited for the bonding of electrical modules to card bodies.

The theological properties are listed in Table 2 below. Tab. 2

Claims

claims

1. Adhesive film, consisting of a thermoplastic and optionally one or more resins, where a) the adhesive system has a softening temperature of greater than 65 ° C and less than 125 ° C b) a melt flow index (ISO 1133) of greater than 3 and less than 100 cm having from ^3/10 minutes c) a measured by test method a storage modulus G 'at 23 ° C of greater than 10 ⁷ Pas, d) a measured by test method a loss modulus G "at 23 ° C of greater than 10 ⁶ Pas, e) and a by Test method A measured crossover of less than 125 ° C.

2. Adhesive film according to claim 1, characterized in that the layer thickness is between 10 and 100 microns, particularly preferably between 30 and 80 microns.

3. Adhesive film according to at least one of the preceding claims, characterized in that copolyamides, polyethyl vinyl acetates, polyvinyl acetates, polyolefins, polyurethanes and copolyesters are particularly preferably used as thermoplastics.

4. Adhesive film according to at least one of the preceding claims, characterized in that epoxy, and / or phenol and / or novolak resins are used as the reactive resin.

5. Use of an adhesive film according to one of the preceding claims for gluing chip modules in card bodies.

6. Use of an adhesive film according to one of the preceding claims for gluing on polyimide, polyester or epoxy-based chip modules and on PVC, ABS, PET, PC, PP or PE card bodies. A method for producing a heat-activatable adhesive tape, characterized in that an adhesive film according to claims 1 to 4 is coated on a release paper or a release film.