KR20190036480A - Conductive Adhesive Film Having Improved Moisture and Heat Resistance - Google Patents

Abstract

The present invention relates to a conductive adhesive film having excellent heat resistance and moisture resistance. An adhesive layer consists of a conductive adhesive composition comprising: 100 parts by weight of a polyamide resin represented by chemical formula 1; 100 to 400 parts by weight of a conductive metal; and 0.1 to 5 parts by weight of a siloxane compound. In addition, the adhesive layer is laminated on a surface of a substrate to improve the heat resistance of the adhesive film and is easy to cure with the siloxane compound to improve the moisture resistance. More specifically, the adhesive film has improved long-term reliability against the heat resistance and the moisture resistance.

Description

{Conductive Adhesive Film Having Improved Moisture and Heat Resistance}

The present invention relates to a conductive adhesive film having excellent heat resistance and moisture resistance, and relates to a conductive adhesive film exhibiting excellent both heat resistance and moisture resistance by including an adhesive composition comprising a polyamide resin having high heat resistance and a water- .

In recent years, the possibility of generating electromagnetic waves has been rapidly increasing through high efficiency, high power consumption, and highly integrated electric / electronic products, and regulations are being tightened. Accordingly, a technique for shielding electromagnetic waves has been developed.

Conventionally, a metal shielding material has been used. In the case of IT brackets used for portable display products such as mobile phones, pads, and notebooks, high rigidity and EMI shielding are required because they protect LCDs, shield electromagnetic waves, Metal such as magnesium, aluminum, and stainless steel was used as a material for the frame or the like. Such a metal material shielding material has an advantage of effectively shielding electromagnetic waves, but it is produced by a die-casting method and has a high production cost and a high defect rate.

Due to these problems, a variety of electromagnetic wave shielding films have recently been developed. In particular, since heat resistance and moisture resistance according to the application of the film should be ensured, films having such properties are actively developed.

For example, in Korean Patent Publication No. 10-1714771, 100 to 400 parts by weight of a conductive metal is added to 100 parts by weight of a polymer resin; And 0.01 to 5 parts by weight of a siloxane-amic acid compound obtained by reacting a tetracarboxylic dianhydride compound with at least one alkoxysilane compound of 3-aminopropyltrimethoxysilane and 3-aminopropyltriethoxysilane A conductive adhesive film having excellent heat resistance and moisture resistance is produced by applying the composition.

In addition, Korean Patent Publication No. 10-0841193 discloses a composition comprising a carboxyl-modified polyacetal resin as a component of a binder part, which is excellent in heat resistance, moisture resistance, and mechanical properties, and particularly capable of maintaining adhesion reliability under high temperature and high humidity conditions Film is disclosed.

However, since such a conductive adhesive film has the effect of controlling the molecular weight of the resin or limiting the type of silane to obtain the effect of heat resistance and moisture resistance, there is a limitation in high temperature and high humidity reliability at the time of using for a long time.

Korean Patent Publication No. 10-1127112 Korean Patent Registration No. 10-0848663

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems of the prior art, and it is an object of the present invention to improve the heat resistance of a film by controlling the number of amine functional groups of the polyamide resin, It is an object of the present invention to provide an adhesive film having improved moisture resistance and improved long-term reliability against heat resistance and moisture resistance.

In order to achieve the above object, the conductive adhesive film having excellent heat resistance and moisture resistance of the present invention comprises 100 parts by weight of a polyamide resin represented by the general formula (1); 100 to 400 parts by weight of a conductive metal; And 0.1 to 5 parts by weight of a siloxane compound is laminated on the surface of the substrate.

[Chemical Formula 1]

(Wherein n is an integer of 50 to 1,000)

At this time, the conductive metal may be one or more of gold, silver, copper, iron, nickel, and tin, and the siloxane compound may be amamic siloxane.

The conductive adhesive film according to the present invention has a polyamide resin as a main component and improves the heat resistance of the film by controlling the number of amine functional groups of the polyamide resin and improves the moisture resistance due to easy curing with the siloxane compound. And the long-term reliability against humidity is improved.

Fig. 1 is a photograph showing the result of a solder floating test on the conductive adhesive film of Example (a) and Comparative Example (b).
Fig. 2 is a graph showing an electromagnetic shielding performance evaluation measurement of the conductive adhesive film of Example (a) and Comparative Example (b).

Hereinafter, the present invention will be described in more detail. The terms and words used in the present specification and claims should not be construed as limited to ordinary or dictionary terms and the inventor may appropriately define the concept of the term in order to best describe its invention It should be construed as meaning and concept consistent with the technical idea of the present invention.

The present invention relates to a conductive adhesive film having excellent heat resistance and moisture resistance, which comprises 100 parts by weight of a polyamide resin represented by the general formula (1); 100 to 400 parts by weight of a conductive metal; And 0.1 to 5 parts by weight of a siloxane compound is laminated on the surface of the substrate.

[Chemical Formula 1]

(Wherein n is an integer of 50 to 1,000)

The polyamide resin constituting the conductive adhesive composition may be prepared by polycondensing an aromatic dicarboxylic acid and an aliphatic diamine in the structure in which p-xylene is contained in the main chain. The polyamide resin produced by this method has a longer methyl group depending on the number of carbon atoms of the aliphatic diamine. As a result of various experiments, it has been found that the shorter the methyl group is, the better the heat resistance and the moisture resistance are. This is due to the increase in the number of amine functional groups. As the number of amine functional groups increases, the heat resistance improves.

In addition, the conductive metal is used in the form of a metal powder as an electrically conductive metal. As the conductive metal, any one or more of gold, silver, copper, iron, nickel, and tin may be used. In order to keep the sedimentation rate relatively low in mixing with the polyamide resin, It is preferable to use a silver powder when it is excellent and considering the electrical contact forming ability and economical efficiency between the particles.

The conductive metal particles may have various shapes such as a spherical shape, a plate shape, and an amorphous shape. However, when considering the formation of an electrical contact, it is preferable to use a mixture of plate-like (flaky), fibrous and dendritic phases appropriately.

The particle size of the conductive metal is preferably 1 to 100 mu m, more preferably 10 to 50 mu m. If the particle size of the conductive metal is too small, the probability of forming an electrical contact is low and high electrical conductivity can not be obtained. If the particle size of the conductive metal is too large, it is difficult to produce a thin film having uniform surface and physical properties .

The conductive metal is preferably used in an amount of 100 to 400 parts by weight based on 100 parts by weight of the polyamide resin. If the amount of the conductive metal is too small, the viscosity of the composition is too low to be applied to form a thin film having a uniform surface. If the conductive metal is contained too much, the adhesive strength is significantly decreased and the application itself is difficult.

Further, in the present invention, a siloxane compound is used for improving the adhesive strength, and in particular, an amic acid-siloxane compound is preferably used to improve the reactivity with the polyamide. As the amic acid-siloxane compound, those obtained by reacting a tetracarboxylic dianhydride compound and an alkoxysilane compound in a polar organic solvent may be used.

Examples of the tetracarboxylic dianhydride include pyromellitic dianhydride (PMDA), 3,3 ', 4,4'-benzophenone tetracarboxylic dianhydride (BTDA), 3,3', 4,4 '-Biphenyl tetracarboxylic dianhydride (BPDA), 3,3', 4,4'-oxydiphthalic dianhydride (ODPA), 3,3 ', 4,4'-hexafluoroisopropyl Naphthalene tetracarboxylic dianhydride (NTD), 1,2,3,4-cyclobutane tetracarboxylic dianhydride (CBDA), 1,4-cyclohexanetetracarboxylic dianhydride , 1,2,3,4-cyclopentanetetracarboxylic dianhydride (CPDA), 5- (2,5-dioxotetrahydrofuryl) -3-methyl-3-cyclohexene- (DOTDA), bicyclopentene dihydrohalide (DOTDA), tetracycline dicarboxylic acid dianhydride (DOTDA), 4- (2,5-dioxotetrahydrofuran- -2,3,5,6-tetracarboxylic dianhydride (BODA), ethylene di The like Nu-tetra acetic dianhydride (EDTD) may be used.

Examples of the alkoxysilane compound include vinyltrimethoxysilane, vinyltriethoxysilane, vinylbutyltriethoxysilane, vinyltri (beta-methoxy) silane, vinyltri (beta-ethoxy) silane, acryloxypropyl Acryloxypropyltrimethoxysilane, trimethoxysilane, acryloxypropyltriethoxysilane, acryloxypropylmethyldimethoxysilane, gamma-methacryloxypropyltrimethoxysilane, gamma-methacryloxypropyltriethoxysilane, gamma-methacryloxypropylmethyl Tetramethoxysilane, tetrapropoxysilane, tetraisopropoxysilane, tetraisopropoxysilane, tetramethoxysilane, tetramethoxysilane, tetramethoxysilane, tetramethoxysilane, tetramethoxysilane, tetramethoxysilane, butoxysilane, tetra-tert-butoxysilane, methyltrimethoxysilane, methyltriethoxysilane, methyltributoxysilane, ethyltrimethoxysilane, ethyltrimethoxysilane, Ethyl triisopropoxy silane, ethyl tri butoxy silane, butyl trimethoxy silane, phenyl trimethoxy silane, 3-methyl trimethoxy silane, dimethyl dimethoxy silane, diphenyl dimethoxy silane, dibutyl dimethoxy silane, Triphenylmethoxysilane, trimethyldimethoxysilane, trimethylethoxysilane, tributylmethoxysilane, tributylethoxysilane, trifluoromethyltrimethoxysilane, trifluoromethyltriethoxysilane, trifluoropropyltrimethoxysilane, Nonafluorobutyltriethoxysilane, nonafluorobutyltriethoxysilane, nonafluorohexyltrimethoxysilane, nonafluorohexyltriethoxysilane, nonafluorohexyltriethoxysilane, nonafluorobutyltriethoxysilane, nonafluorobutyltriethoxysilane, nonafluorohexyltrimethoxysilane, nonafluorohexyltriethoxysilane, tridecafluoro Heptadecafluorodecyltrimethoxysilane, heptadecafluorodecyltrimethoxysilane, heptadecafluorodecyltrimethoxysilane, heptadecafluorodecyltrimethoxysilane, heptadecafluorodecyltrimethoxysilane, heptadecafluorodecyltrimethoxysilane, heptadecafluorodecyltrimethoxysilane, Isopropyl silane, isopropyl silane, 3-trimethoxysilylpropylpentadecafluorooctate, 3-triethoxysilylpropylpentadecafluorooctate, 3-trimethoxysilylpropylpentadecafluoroctoamide, 3-tri 2-trimethoxysilylethylpentadecafluorodecylsulfide, 2-triethoxysilylethylpentadecafluorodecylsulfide, pentafluorophenyltrimethoxysilane, pentaerythritol tetramethoxysilane, pentaerythritol tetramethoxysilane, (Perfluoroaryl) trimethoxysilane, 4- (perfluorotolyl) triethoxysilane, dimethoxybis (pentafluorophenyl) silane, diethoxybis (4 (3,4-epoxycyclohexyl) ethyltrimethoxysilane, and the like can be used. In place of the alkoxy group, a vinyl group, an epoxy group, a methacryl group, a mercapto group, an isocyanate group, A substituent such as an aminoalkyl group, Or a silane compound having at least 3 carbon atoms, such as 3-aminopropyltrimethoxysilane and 3-aminopropyltriethoxysilane.

The amic acid-siloxane compound may be included in an amount of 0.1 to 5 parts by weight based on 100 parts by weight of the polyamide resin. If the amount of the amic acid-siloxane compound is too small, the effect of increasing the adhesive strength is insignificant, and if the amamic acid-siloxane compound is included too much, the surface resistance is greatly increased.

In addition, the adhesive composition of the present invention may further include a silane compound in order to improve the adhesiveness. As the silane compound, the alkoxysilane compound may be used. When the silane compound is included in an amount of 0 to 30 parts by weight based on 100 parts by weight of the polyamide resin, the silane compound is preferable in terms of an adhesive strength improving effect and a process efficiency.

Further, the adhesive composition of the present invention may further comprise a curing agent and a curing accelerator for curing. As the curing agent, an amide-based curing agent may be used, and as the amide-based curing agent, dicyandiamide and the like may be used, but the present invention is not limited thereto. As the curing accelerator, imidazole-based, triphenylphosphine (TPP), tertiary amines and the like may be used, but the present invention is not limited thereto.

The curing agent may be included in an amount of 0 to 30 parts by weight based on 100 parts by weight of the polyamide resin. The curing accelerator may be added in an amount of 0 to 10 parts by weight based on 100 parts by weight of the polyamide resin.

Accordingly, the conductive adhesive composition of the present invention exhibits excellent adhesiveness, conductivity, heat resistance and moisture resistance.

The conductive adhesive film of the present invention comprises the steps of: applying the conductive adhesive composition onto a release film; And drying the conductive adhesive composition to form an adhesive layer.

The conductive adhesive composition is dissolved in a mixed solvent of one or more selected from the group consisting of dimethylformamide, toluene, water, ethanol, methanol, isopropyl alcohol, furfuryl alcohol, phenol and methyl ethyl ketone to prepare a uniformly mixed conductive paste After the preparation, it is applied on a release film. As the release film, a base film formed of polyethylene, polypropylene, polyethylene terephthalate or the like and treated with a release agent such as a silicone-based, fluorine-based, or long-chain alkyl acrylate base is used for easy peeling.

The conductive paste may be applied by a comma coating, a spin coating, a gravure printing, a reverse roll coating, or a screen printing, but the present invention is not limited thereto.

Further, the conductive paste is dried to remove the solvent, whereby a conductive adhesive film in the form of a thin film can be produced. The drying conditions may be appropriately adjusted according to the type of the solvent used, but it is preferable that drying is performed at a temperature in the range of 80 to 200 ° C.

The conductive adhesive film obtained through the above process may exhibit a thickness of about 10 to 1000 mu m, preferably 50 to 200 mu m. In the conductive adhesive film, the thickness of the adhesive layer excluding the release film is preferably 10 to 100 탆.

(Surface resistance), peel strength, moisture resistance (peel strength), heat resistance (contact resistance), and lead content of the conductive adhesive film (example) of the present invention and the commercially available product CBF-300 conductive adhesive film Heat resistance was evaluated.

In Example, 3.6 parts by weight of an amic acid-siloxane compound prepared by reacting 100 parts by weight of a polyamide resin (n = 800) represented by Chemical Formula 1, 230 parts by weight of copper, pyromellitic dianhydride and vinyltrimethoxysilane And 1.7 parts by weight of 2,4-benzenedicarboxylic acid-1- (3-propyltriethoxysilane) amide were dissolved in methyl ethyl ketone to prepare a conductive paste, which was then laminated on the surface of the substrate to form an adhesive layer To form a conductive adhesive film.

Each specimen was made 10 mm × 150 mm, and specimens were placed between the coupon and the SUS substrate. The specimens were pressed at 3 ° C. for 30 minutes at 150 ° C. using a hot press machine. The measurement method was measured according to ASTM D991, and a low resistance meter of HIOKI Co. was used for the measurement.

Further, the peel strength and moisture resistance were measured according to ASTM D3330 using a UTM (Universal Testing Machine). The test speed was 50 mm / min. The load cell was tested at 90 ° angle using 100N. SUS, PI and ENIG were used as the adherend.

A total of 5 measurements were made to obtain the average value. The results are shown in Table 1.

Contact Resistance (Ω / sq) Surface resistance (Ω / sq) Peel strength (N / cm) Example 1.6 × 10 ^-2 7.2 x 10 ^-2 SUS 25.79 PI 27.79 ENIG 11.92 Comparative Example 2.6 x 10 ^-2 1.1 x 10 ^-1 SUS 21.24 PI 17.93 ENIG 7.48

As shown in Table 1, the contact resistances of the films of Examples and Comparative Examples were similar to each other. Further, the SUS base material showed a higher peel strength in Examples, and the PI and ENIG base materials exhibited significantly higher peel strength in Examples. Particularly, the peel strength was 50% or more with respect to the PI substrate. Therefore, the adhesive film of the examples is superior in physical properties to commercially available adhesive films, and can be applied to various substrates, and thus it has been found that the adhesive film has superior versatility.

In addition, the moisture resistance of the adhesive films of Examples and Comparative Examples was tested. The measurement was carried out in accordance with ASTM D330. The specimen preparation method was the same as that of the conventional peeling strength sample preparation method. The specimens were maintained at 85 ° C and 85% RH for 250 hours using a thermo-hygrostat, and then the peel strength was measured using UTM. A total of 5 measurements were made to obtain the average value. The results are shown in Table 2.

Peel strength (N / cm) Example SUS 11.74 PI 13.76 ENIG 6.90 Comparative Example SUS 11.63 PI 10.90 ENIG 4.01

From the results of Table 2, it was found that the peel strength was similar in the SUS substrate, but the peel strength of the examples was better in the PI and ENIG substrates, indicating that the substrate had moisture resistance to various substrates.

The heat resistance of the adhesive films of Examples and Comparative Examples was evaluated. The measurement was carried out in accordance with ASTM D991, and the film prepared on SUS and a film made in Japan were submitted to a reflow process at 260 캜 for 3 seconds, and the contact resistance was measured. The number of reflows was 1, 3, and 5 times. The results of the contact resistance measurement after reflow are shown in Table 3, and the results of the contact resistance measurement after reflow are shown in Table 4.

Reflow Thickness (mm) Contact Resistance (Ω) Surface resistance (Ω / sq) Example I'm 0.06 1.4 x 10 ^-2 1.6 × 10 ^-2 after 0.06 3.5 × 10 ^-2 3.6 x 10 ^-1 Comparative Example I'm 0.06 3.4 x 10 ^-2 2.6 x 10 ^-2 after 0.06 5.3 × 10 ^-2 2.4 x 10 ^-1

As shown in Table 3, the resistance value before reflow was 1.6 × 10 ^-2 Ω / sq in the embodiment, and the resistance value after reflow was about 10 times that before 3.6 × 10 ^-1 Ω / sq reflow And increased resistance values. In the comparative example, the resistance value before reflow was 2.6 × 10 ^-2 Ω / sq, and the resistance value after reflow was 2.4 × 10 ^-1 Ω / sq, indicating that the resistance value of CBF-300 also increased ten times .

These results show that the resistance value changes little for both the example and the comparative example in the measurement results after the reflow 1, 3, and 5 times, and the invisible cracks are generated in the film itself after reflow, Respectively. Also, even when the number of reflows was increased, it was judged that there was no change in resistance value because no crack occurred.

However, as a result of comparing the contact resistances of Examples and Comparative Examples, the resistance values of Examples were lower than those of Comparative Examples before and after reflow. Thus, it was confirmed that the adhesive films of Examples were more excellent in heat resistance.

In order to evaluate the heat resistance of the adhesive films of Examples and Comparative Examples at the time of soldering, it was observed through the solder floating test that the film was deformed.

For the specimen preparation method, a conductive adhesive film was applied between the SUS substrate and the PI film using a roll coating apparatus, and then the specimen prepared in the solder floating equipment was placed at 280 ° C. for 10 seconds, and peeling between the PI film and the film was observed after 10 seconds . The results are shown in Fig.

1, it can be seen that no exothermic phenomenon was observed in both of the examples and the comparative examples. It can be seen from the fact that the conductive adhesive film of the present invention has lead heat resistance even at a temperature of 280 ° C or higher, similar to a commercially available conductive adhesive film .

In order to evaluate the electromagnetic shielding (EMI) of the adhesive films of Examples and Comparative Examples, the measurement was commissioned to the Institute of Composite Materials, Korea Institute of Science and Technology. The measurement method of electromagnetic shielding performance was measured according to the ASTM standard method. Among the various measurement methods, the conductive adhesive film was measured by the ASTM D4935-10 method. Value is the most reliable measurement method.

The evaluation results of the electromagnetic wave shielding performance of the produced film are shown in Table 4 and FIG.

Frequency (MHz) Embodiment (dB) Comparative Example (dB) 303 52 53 1503 51 53 3003 52 53 4203 51 54 5402 54 55 6602 52 53 7802 52 56 9002 50 53 10202 51 55 11402 52 54 12602 53 54 13802 51 54 15002 54 55

The shielding measurement frequency range is from 30 MHz to 1.5 GHz, with an average of 54 dB measured in the example. Also, in the comparative example, an average value of 52 dB was measured.

In addition, the shielding efficiency (SE) is expressed as Equation (1). When the shielding efficiency is calculated using Equation (1), the shielding efficiency of the embodiment is 99.852%, and the shielding efficiency of the comparative example is 99.742%. Therefore, it was confirmed that the adhesive film of the present invention exhibits an electromagnetic shielding performance equivalent to that of a commercially available adhesive film.

While the invention has been shown and described with reference to certain embodiments thereof, it will be understood by those skilled in the art that various changes and modifications may be made therein without departing from the spirit and scope of the invention as defined in the appended claims. Change is possible. Such variations and modifications are to be considered as falling within the scope of the invention and the appended claims.

Claims (3)

100 parts by weight of a polyamide resin represented by the general formula (1);
100 to 400 parts by weight of a conductive metal;
0.1 to 5 parts by weight of a siloxane compound;
Wherein the adhesive layer is laminated on the surface of the base material.
[Chemical Formula 1]

(Wherein n is an integer of 50 to 1,000)
The method according to claim 1,
Wherein the conductive metal is at least one of gold, silver, copper, iron, nickel, and tin, and has excellent heat resistance and moisture resistance.
The method according to claim 1,
Wherein the siloxane compound is an amic acid-siloxane compound, and is excellent in heat resistance and moisture resistance.

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