JP2001064547A - Active energy ray-curable electroconductive paste, and conductor circuit and non-contact id using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electroconductive paste which can be applicable to a base material having poor heat resistance and needs a very short time for a curing process in the manufacture of a conductive circuit so that it realizes high mass productivity of conductive circuits and is effective for reducing the production cost of a non-contact ID. SOLUTION: There is provided an electroconductive paste comprising an electroconductive substance and active energy ray-polymerizable compound which gives a cured film having an internal stress of 5-50 MPa when cured by an electron beam having an accelerated voltage of 150 kV at an irradiation dose 40 kGy. A method for manufacturing a conductive circuit comprises a step of forming a circuit pattern on a substrate using the electroconductive paste and irradiating it with an active energy ray. The conductive circuit is manufactured by such process. The non-contact ID is prepared by mounting the conductive circuit and an IC chip on a substrate.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a conductive paste for electronic materials. More specifically, the present invention relates to a conductive paste which can form a circuit pattern even on a substrate having poor heat resistance and can be cured in an instant so that mass production of a conductive circuit is good.

[0002]

2. Description of the Related Art In recent years, the demand for non-contact IDs, specifically non-contact IC cards and non-contact IC tags for telephone cards, commuter passes, and other uses has been increasing. Non-contact IC cards and non-contact IC tags use radio waves to exchange data such as the remaining amount of telephone cards and the expiration date of commuter passes, and the power required for communication is also generated by external radio waves Let me. With the spread of these non-contact IDs (non-contact type IC cards and non-contact type IC tags), reduction of the manufacturing cost is also a key. As a method of manufacturing a circuit for communication with the outside and power generation (commonly called an antenna circuit), an etching method from a copper-clad substrate, a copper wire winding method,
A printing method using a thermosetting or thermoplastic conductive paste has been put to practical use.

[0003]

However, the etching method and the copper wire winding method have many problems because the steps are complicated and waste liquid treatment is required in a later step. In addition, since the thermosetting conductive paste uses a thermosetting resin and / or an inorganic substance such as glass frit as a binder, it is necessary to heat the base material (substrate) at a high temperature after applying or printing. Was. Curing by heating requires a large amount of energy, heating time, and a floor area for installing a heating device, is not only uneconomical, but also has the following major restrictions.

That is, a conductive paste using an inorganic substance such as a glass frit as a binder usually requires firing at 800 ° C. or higher, and therefore cannot be applied to a synthetic resin base material. On the other hand, a conductive paste using a thermosetting resin as a binder can be applied to a synthetic resin-based substrate, but the substrate is deformed by heating when the paste is cured, and the resulting printed wiring is formed. This was a major obstacle, as it hindered the mounting of components in subsequent processes using circuits.

[0005] Conductive circuits using a thermoplastic conductive paste are also widely used for personal computer keyboards and the like. However, since a substrate such as polyethylene terephthalate shrinks during the process of drying the conductive paste, a countermeasure is taken as a countermeasure. And pretreatment such as annealing. In addition, drying requires a time of 30 to 60 minutes, and has drawbacks such as lack of solvent resistance.

Accordingly, the present invention improves the above-mentioned various problems, and can be used for a substrate having poor heat resistance. It is an object of the present invention to provide a conductive paste which has high mass productivity and is effective in reducing the manufacturing cost of a non-contact ID.

[0007]

Means for Solving the Problems The present inventors have proposed a conductive paste using an active energy ray polymerizable compound as a binder in which the internal stress of a cured film when cured by an electron beam is within a specific range. The present inventors have found that a circuit pattern having an appropriate volume specific resistance value and good substrate adhesion can be formed on a substrate having poor heat resistance by being cured by irradiation with an energy ray, and the present invention has been accomplished. In addition, the present inventors have found that a conductor circuit can be easily mass-produced by using the above-mentioned conductive paste, and the obtained conductor circuit is suitable as a non-contact ID circuit.

That is, the present invention is a conductive paste containing a conductive substance and an active energy ray polymerizable compound, wherein the active energy ray polymerizable compound is cured by an electron beam having an acceleration voltage of 150 kV and an irradiation dose of 40 kGy. An active energy ray-curable conductive paste characterized in that the internal stress of the cured film when stiffened is 5 to 50 MPa. Further, the present invention is a method for manufacturing a conductor circuit, comprising forming a circuit pattern on a base material using the active energy ray-curable conductive paste and irradiating the circuit pattern with active energy rays. Further, the present invention is a conductor circuit manufactured by the above method. Further, the present invention provides a non-contact I / O circuit having the above-described conductor circuit and IC chip mounted on a substrate.
D.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The active energy ray polymerizable compound used in the conductive paste of the present invention has an internal stress of 5 when the compound is cured with an electron beam of an acceleration voltage of 150 kV and an irradiation dose of 40 kGy. It is a compound having a pressure of ５０50 MPa, preferably 10-40 MPa. When two or more active energy ray polymerizable compounds are used,
The internal stress of the mixture must be within the above range. The internal stress of the cured film of the active energy ray polymerizable compound is 5M
When it is less than Pa, an appropriate volume specific resistance value as a conductive paste is not exhibited. On the other hand, if it exceeds 50 MPa, the adhesion of the conductive paste to the base material is low, and does not reach a practical level.

[0010] The internal stress of the cured film of the active energy ray polymerizable compound is measured by the following method. That is, 1
An active energy ray polymerizable compound whose internal stress is to be measured is uniformly applied to a non-deposited surface of a 2 μm aluminum-deposited polyethylene terephthalate (hereinafter referred to as PET) film by a spin coater to a thickness of about 10 μm to form a film. I do. Next, the coating is irradiated with an electron beam having an acceleration voltage of 150 kV and an irradiation dose of 40 kGy in a nitrogen atmosphere to cure the coating. The obtained aluminum deposition P
The cured film on the ET film is curled in an arc shape with the cured film inside and the PET film outside because of curing shrinkage. The radius of curvature of this arc is measured.

Further, the previously obtained aluminum-deposited PE
The elastic modulus of the cured film on the T film is calculated from the elastic modulus of the PET film alone and the elastic modulus of the composite film of the cured film and the PET film. The internal stress (P0) of the cured film on the aluminum vapor-deposited PET film is the radius of curvature (r: unit m)
m), modulus of elasticity of substrate (F: unit Pa), modulus of elasticity of cured film (E: unit Pa), thickness of PET film (d1: unit mm), thickness of cured film (d2: unit mm) Is calculated from the following equation. P0 = 2 {F * (d1) ³ + E * (d2) ³ } / 3r
(D2) ²

The active energy ray polymerizable compound is a compound which is polymerized by irradiation with an active energy ray, and a compound having an ethylenically unsaturated group is preferably used. As the compound having an ethylenically unsaturated group,
(Meth) acrylic acid, (meth) acrylate compounds,
Examples include vinyl ether compounds and polyallyl compounds. These compounds can be used alone or in combination of two or more.

Among the (meth) acrylate compounds, monofunctional (meth) acrylate compounds include methyl (meth) acrylate, ethyl (meth) acrylate,
n-butyl (meth) acrylate, t-butyl (meth)
Acrylate, isobutyl (meth) acrylate, methoxydiethylene glycol (meth) acrylate, methoxytriethylene glycol (meth) acrylate, n
-Butoxyethyl (meth) acrylate, 2-phenoxyethyl (meth) acrylate, cyclohexyl (meth)
Acrylate, tetrahydrofurfuryl (meth) acrylate, isobonyl (meth) acrylate, benzyl (meth) acrylate, 2-hydroxyethyl (meth)
Acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate,
4-hydroxybutyl (meth) acrylate, (meth)
Acryloyloxyethyl hydrogen succinate,
(Meth) acryloyloxypropyl hydrogen phthalate, (meth) acryloyloxyethyl 2-hydroxypropyl phthalate, glycidyl (meth) acrylate,
2-Hydroloxy-3-acryloyloxypropyl (meth)
Acrylate and the like.

The polyfunctional (meth) acrylate compounds include 1,6-hexanediol di (meth) acrylate, triethylene glycol di (meth) acrylate, tripropylene glycol di (meth) acrylate and neopentyl glycol. Di (meth) acrylate,
Ethylene oxide-modified bisphenol A di (meth) acrylate, propylene oxide-modified bisphenol A di (meth) acrylate, trimethylolpropane tri (meth) acrylate, ethylene oxide-modified trimethylolpropane tri (meth) acrylate, propylene oxide-modified trimethylol propane tri (Meth) acrylate, pentaerythritol tetra (meth) acrylate, ditrimethylolpropanetetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate, pentaerythritol di (meth) acrylate, pentaerythritol tri (meth) acrylate
Acrylate, dipentaerythritol tetra (meth)
Acrylate, dipentaerythritol penta (meth)
Examples include acrylate, urethane acrylate, epoxy acrylate, and ester acrylate.

When a trifunctional or higher urethane acrylate is used among the above polyfunctional (meth) acrylate compounds,
Although the curing shrinkage increases and the volume resistivity decreases,
Adhesion does not decrease, and an excellent active energy ray-curable conductive paste can be obtained. Among the vinyl ether compounds, examples of monofunctional vinyl ether compounds include hydroxyethyl vinyl ether, hydroxybutyl vinyl ether, cyclohexane dimethanol monovinyl ether, cyclohexyl vinyl ether, and the like.

The polyfunctional vinyl ether compounds include ethylene glycol divinyl ether, diethylene glycol divinyl ether, triethylene glycol divinyl ether, propylene glycol divinyl ether, dipropylene glycol divinyl ether,
Tripropylene glycol divinyl ether, neopentyl glycol divinyl ether, 1,4-butanediele divinyl ether, 1,6-hexanediol divinyl ether, glycerol divinyl ether, trimethylolpropane divinyl ether, 1,4-dihydroxycyclohexane divinyl ether, Examples thereof include divinyl ether compounds such as 1,4-dihydroxymethylcyclohexane divinyl ether, bisphenol A diethoxy divinyl ether, and bisphenol S diethoxy divinyl ether.

Glycerol trivinyl ether;
Trifunctional or higher polyvinyl such as sorbitol tetravinyl ether, trimethylolpropane trivinyl ether, pentaerythritol trivinyl ether, pentaerythritol tetravinyl ether, dipentaerythritol hexavinyl ether, dipentaerythritol polyvinyl ether, ditrimethylolpropane tetravinylether, ditrimethylolpropane polyvinylether, etc. Examples include ether compounds.

Examples of the conductive substance used in the conductive paste of the present invention include gold, silver, copper, silver-plated copper powder, silver-copper composite powder, silver-copper alloy, nickel, chromium, palladium, aluminum, and tungsten. , Molybdenum, metal powder such as platinum, inorganic powder coated with these metals, silver oxide, metal oxide powder such as indium oxide, powder coated with these metal oxides, or carbon black,
Examples include graphite. These conductive substances may be used in combination of two or more. Among the conductive substances, silver powder is preferable because of high conductivity and little increase in resistance value due to oxidation.

The shape of the conductive material may be any of a granular shape, a spherical shape, a flake shape, a flake shape, a plate shape, a dendritic shape, a cubic shape and the like. From the viewpoint of dendritic, scaly or spherical ones are preferred. The conductive material has an average particle size of 0.1.
Those having an average particle diameter of 1 μm to 50 μm are preferably used from the viewpoint of conductivity and fluidity of the conductive paste. The average particle size in the present invention is a volume average particle size measured by a laser diffraction method.

The compounding ratio of the conductive substance and the active energy ray polymerizable compound in the conductive paste of the present invention is based on the total amount of the conductive substance and the active energy ray polymerizable compound. The active energy ray polymerizable compound is 5 to 45% by weight. When the compounding ratio of the conductive substance exceeds 95% by weight, the coating film formed using the conductive paste becomes brittle and the conductivity decreases. If the content is less than 55% by weight, sufficient conductivity cannot be obtained. Preferably, the conductive substance is 90 to 60% by weight,
The amount of the active energy ray polymerizable compound is 10 to 40% by weight.

When the conductive paste of the present invention is cured with ultraviolet rays, a photopolymerization initiator or a photopolymerization initiator may be added to the conductive paste. Further, a solvent can be added to the conductive paste of the present invention for the purpose of adjusting the viscosity. As the solvent, for example, ketones, aromatics, alcohols, cellosolves, ether alcohols, esters and the like can be used. These solvents are 2
A combination of more than two types may be used. Ketones include methyl ethyl ketone, methyl isobutyl ketone,
Examples include pentanone and 2-heptanone, and examples of the aromatics include toluene, xylene, ethylbenzene, and chlorobenzene.

Examples of alcohols include methanol, ethanol, isopropanol, normal butanol, isobutanol, ethylene glycol, propylene glycol, and benzyl alcohol. Examples of cellosolves include methyl cellosolve, ethyl cellosolve, butyl cellosolve, and hexyl cellosolve. Can be Ether alcohols include propylene glycol methyl ether, propylene glycol ethyl ether, propylene glycol butyl ether and the like, and esters include ethyl acetate, butyl acetate, normal cellosolve acetate, butyl carbitol acetate and the like.

The conductive circuit can be manufactured by forming a circuit pattern on the base material using the conductive paste of the present invention and irradiating the circuit with active energy rays. As the substrate, an epoxy laminate, a paper-phenol substrate, paper, synthetic paper, a polyethylene terephthalate film, a polypropylene film, a vinyl chloride film, or the like can be used. The circuit pattern can be formed by silk screen printing, offset printing, metal mask printing, or the like.

The active energy ray is an energy ray used as a curing trigger for the conductive paste. Examples of the active energy ray include ultraviolet rays, electron rays, γ rays, infrared rays, and visible rays. An electron beam is preferred because it has little effect on the substrate on which the conductive circuit is formed. The active energy ray has an internal stress of 5 to 50 in the cured film of the active energy ray polymerizable compound in the conductive paste.
It is preferable to irradiate under the condition that the pressure becomes MPa. When the internal stress of the cured film of the active energy ray polymerizable compound in the conductive paste is less than 5 MPa, the volume resistivity of the conductive paste increases, and when it exceeds 50 MPa, the base material of the conductive paste Adhesion decreases.

The electron beam is preferably 100 to 1000 k
V, more preferably an electron beam irradiation device having an acceleration voltage in the range of 150 to 250 kV. Acceleration voltage 10
When the electron beam is less than 0 kV, it is difficult to sufficiently cure the inside of the conductor circuit, and when the electron beam exceeds 1000 kV, the damage to the substrate is increased. The irradiation dose (dose) of the electron beam is preferably in the range of 1 to 1000 kGy, more preferably in the range of 5 to 200 kGy. If the irradiation dose is less than 1 kGy, it is difficult to obtain a sufficiently cured conductor circuit, and if the irradiation dose is more than 1000 kGy, damage to the substrate is large, which is not preferable.

The resistance of the conductive paste of the present invention can be reduced by heating it at 120 ° C. or more for about 2 minutes after curing by irradiation with active energy rays. However, 1
Heating at a temperature of 20 ° C. or more cannot be applied to a substrate having poor heat resistance due to deformation or the like. Therefore, in the method of manufacturing a conductive circuit using the conductive paste of the present invention, 80 to 1
It is preferable to perform the pressure treatment while heating at a temperature of about 00 ° C. By using the heat treatment and the pressure treatment together, the orientation of the conductive substance can be promoted at a temperature of about 80 to 100 ° C. at which the base material does not deform and the like, and the resistance value can be reduced.

If the heating is performed at a temperature lower than 80 ° C., the orientation of the conductive substance cannot be sufficiently promoted to reduce the resistance value.
If the heating is performed at a temperature exceeding the above range, the deformation of the substrate may occur when a substrate having extremely poor heat resistance is used, which is not preferable. The pressure treatment can be performed by a roll, preferably 5 to 20 kgf / cm, more preferably 8 to 1 kgf / cm.
A pressure of 2 kgf / cm is applied. Pressure is 5k
In the case of gf / cm, the orientation of a conductive material sufficient to reduce the resistance cannot be promoted, and in the case of more than 20 kgf / cm, productivity is deteriorated, which is not preferable.

The conductor circuit manufactured by the above method is mounted together with an IC chip on a substrate, and a non-contact ID is obtained. The substrate holds the conductor circuit and the IC chip, and may be the same paper, film, or the like as the substrate of the conductor circuit. The IC chip stores, stores, and calculates data. The contactless ID is
RFID (Radio Frequency Identification), non-contact type IC card, non-contact type IC tag, data carrier (recording medium), wireless card, reader or reader / writer, using radio waves to identify individuals and data It transmits and receives. Applications include payment processing such as fee collection systems and financial management systems, and entry and exit management systems and medical management systems.
D management and history management, road use situation management system and cargo,
There is position management such as a package tracking and management system.

[0029]

Next, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples. In the examples, parts are parts by weight. ◎ Evaluation method (1) Internal stress: An active energy ray polymerizable compound whose internal stress is to be measured is deposited on a 12 μm aluminum deposited PET.
The non-deposited surface of the film was uniformly coated with a spin coater so as to have a thickness of about 10 μm. Next, an acceleration voltage of 150 kV and an absorbed dose of 40 kGy were applied to the coated product in a nitrogen atmosphere.
The composition was cured by irradiation with an electron beam under the conditions described above. The bending radius of curvature on the aluminum vapor-deposited PET film curled in an arc shape due to curing shrinkage was measured with a laser displacement measuring device. Further, the modulus of elasticity of the cured film on the aluminum-deposited PET film was determined by comparing the elastic modulus of the PET film alone with the cured film.
It was calculated from the elastic modulus of the composite film of the ET film. Internal stress of cured film on aluminum deposited PET film (P
0) is the deflection radius of curvature (r: unit mm), the elastic modulus of the substrate (F: unit Pa), the elastic modulus of the cured film (E: unit P)
a), the thickness of the PET film (d1: unit mm), and the thickness of the cured film (d2: unit mm) were calculated by the following formula. P0 = 2 {F * (d1) ³ + E * (d2) ³ } / 3r
(D2) ²

(2) Volume specific resistance value: A conductive paste is applied on a film to a width of 3 mm and a thickness of about 30 μm and cured, and the resistance is measured using a four-probe resistance measuring instrument. The measurement was performed using a measuring instrument, and the volume resistivity was calculated from the measurement result. (3) Adhesion: A 30 μm-thick conductive paste was applied to the film using an edge coater and cured, and the cured film was cross-cut with a cutter knife to perform a cellophane tape peeling test. (4) Influence on the substrate; deformation of the substrate of the obtained conductor circuit;
Coloring and cracking were visually observed.

◎ Abbreviations of compounds used in Examples and Comparative Examples are described. (Polymerizable compound) BS575: 6-functional urethane acrylate (manufactured by Arakawa Chemical Co., Ltd.) UA-306H: 6-functional urethane acrylate (manufactured by Kyoeisha Chemical Co., Ltd.) DPHA: dipentaerythritol hexaacrylate BADGDA: bisphenol A diglycidyl ether diacrylate HX-620 : Bifunctional ester acrylate (manufactured by Nippon Kayaku Co., Ltd.) 4-HBA: 4-hydroxybutyl acrylate TPGDA: tripropylene glycol diacrylate (conductive material) SF-65: Flaky silver powder (manufactured by Degussa Japan, average particle size: 2.) (Photopolymerization initiator) Irg907: 2-methyl-1 [4- (methylthio) phenyl] -2-morpholinopropan-1-one (manufactured by Ciba Specialty Chemicals)

Examples 1 to 4 and Comparative Examples 1 and 2 (a) Method for Preparing Conductive Paste Each component shown in Table 1 was preliminarily mixed with a grinder and then kneaded with three rolls to obtain a conductive paste. The paste was adjusted. (B) Manufacturing Method of Conductor Circuit A circuit pattern was formed on a PET base material that had been subjected to corona treatment in advance by using a 200-mesh stainless steel screen plate using a conductive paste. Next, using an area beam type electron beam irradiation apparatus “Curetron EBC-200-20-30” (manufactured by Nissin High Voltage), acceleration voltage of 175 k
An electron beam was irradiated under the conditions of V and an irradiation dose of 40 Gy to obtain a conductor circuit.

Comparative Example 3 A conductive paste was prepared in the same manner as in Example 1, and a circuit pattern was formed on a PET substrate. Next, using two 120 W metal halide lamps, ultraviolet rays were irradiated from a distance of 20 cm to obtain a conductor circuit. [Comparative Example 4] 91.3 parts of bisphenol F diglycidyl ether ("RE-404S" manufactured by Nippon Kayaku Co., Ltd.), 39.1 parts of resorcil glycidyl ether ("Denacol EX-201" manufactured by Nagase Kasei Kogyo Co., Ltd.), dicyandiamide (AH-154 manufactured by Ajinomoto Co.) 21.9 parts, silver powder "S
794.8 parts of "F-65" and 53.0 parts of n-butyl cellosolve acetate (special grade reagent, manufactured by Tokyo Chemical Industry Co., Ltd.) were premixed with a grinder, and kneaded with three rolls to obtain a conductive paste. Was. Example 1 using this conductive paste
A circuit pattern was formed on the base material in the same manner as described above, and cured by heating at 180 ° C. for 30 minutes using a box oven to obtain a conductor circuit.

Example 5 A conductive paste was prepared in the same manner as in Example 1, a circuit pattern was formed on a substrate, and then an electron beam was irradiated under the same conditions as in Example 1. Furthermore,
A heat and pressure roll treatment was performed at a temperature of 100 ° C. and a pressure of 10 kgf / cm to obtain a conductor circuit. Example 6 A conductor circuit was obtained in the same manner as in Example 5, except that the temperature of the heating and pressing treatment was changed to 25 ° C.

Table 1 shows the compositions of the conductive pastes prepared in the examples and comparative examples, and the evaluation results.

[0036]

[Table 1]

[0037]

According to the present invention, a conductive paste which can be used for a substrate having poor heat resistance and has a very short curing time can be obtained. By using the conductive paste of the present invention, a conductor circuit can be easily mass-produced, and the manufacturing cost of the non-contact ID can be reduced.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) // C08L 101/16 H01B 1/20 A H01B 1/20 H05K 3/12 610B H05K 3/12 610 C08L 101 / 00 F-term (reference) 4E351 BB01 BB31 CC11 CC27 DD01 EE01 EE21 GG20 4J002 BE041 BG041 BG051 BG061 BG071 CD191 CD201 DA026 DA036 DA076 DA086 DA116 DE096 FB076 FD116 GQ00 GQ05 4J038 FB07A01A19A11 NA11 HA11A11A11B DD03 EE42 GG11 5G301 DA03 DA42 DD01

Claims (7)

[Claims] 1. A conductive paste containing a conductive substance and an active energy ray polymerizable compound, wherein the active energy ray polymerizable compound is cured by an electron beam having an acceleration voltage of 150 kV and an irradiation dose of 40 kGy. An active energy ray-curable conductive paste, wherein the internal stress of the cured film is 5 to 50 MPa. 2. A method for producing a conductor circuit, comprising forming a circuit pattern on a substrate using the active energy ray-curable conductive paste according to claim 1, and irradiating the circuit pattern with an active energy ray. 3. The production of a conductor circuit according to claim 2, wherein the active energy ray is irradiated so that the internal stress of the cured film of the active energy ray polymerizable compound in the conductive paste becomes 5 to 50 MPa. Method. 4. The method according to claim 2, wherein the active energy beam is an electron beam. 5. The method for manufacturing a conductor circuit according to claim 2, wherein a heating and pressurizing treatment is performed after the irradiation with the active energy ray. 6. A conductor circuit manufactured by the method according to claim 2. 7. A non-contact ID in which the conductor circuit and the IC chip according to claim 6 are mounted on a substrate.