JP2023064469A - Conductive resin composition, conductive adhesive, cured product, and semiconductor device - Google Patents

Abstract

To provide a conductive resin composition which is useful as a conductive material for a flexible hybrid electronics field, especially, a conductive connection material for a wearable application and an electronic shelf label, is a low temperature drying type, and has high flexibility.SOLUTION: A conductive resin composition contains (A) a thermoplastic resin having a ratio (hard segment: soft segment) of a hard segment to a soft segment of 1:99 to 50:50, and has a weight average molecular weight of 25,000 or more, (B) an organic solvent having a boiling point of 155-205°C, and (C) conductive particles.SELECTED DRAWING: None

Description

TECHNICAL FIELD The present invention relates to a conductive resin composition used in the field of flexible hybrid electronics (hereinafter referred to as FHE).

In recent years, wearable applications using the Internet have attracted increasing attention, and applications in the field of FHE, such as biosensors, are being developed mainly in the fields of sports and healthcare.

As for wearable applications, wristbands, clothes, eyeglasses, etc. are being developed for the purpose of being attached to the human body, and materials that can accommodate the bending and stretching of the human body surface are required.

In these applications, it is necessary to form wiring and mount sensors, capacitors, processors, memories, etc., when giving electrical functions to everything. In the field of FHE, since semiconductors such as processors and memories mounted on these flexible wiring boards cannot be stretchable, low-elasticity conductive adhesives for mounting these semiconductors on flexible wiring boards are used. is required.

As a conductive adhesive, for example, Patent Document 1 below describes "(A) a polyimide silicone resin having two or more phenolic hydroxyl groups in one molecule, (B) an epoxy resin, and (C) a conductive metal powder. A curable resin composition characterized by containing

Patent Document 2 below describes "(A) an epoxy resin, (B) a compound having a (meth)acryloyl group and a glycidyl group, (C) a phenolic resin-based curing agent, (D) a radical polymerization initiator, and (E) A conductive resin composition characterized by containing conductive particles” is disclosed.

Patent Document 3 below discloses a compound having the formula "(A): -R ¹ -O- [wherein R ¹ is a hydrocarbon group having 1 to 10 carbon atoms. ] and a polyether polymer having a terminal group which is a hydrolyzable silyl group, and (B) a conductive adhesive comprising silver particles.

Patent Document 4 below discloses "a conductive adhesive containing a conductive powder, a thermosetting silicone resin, and a solvent".

JP 2005-113059 A International Publication No. 2013/035685 JP 2018-048286 A Japanese Patent Publication No. 2011-510139

However, the curable resin composition of Patent Literature 1 does not have low elasticity, that is, does not have flexibility, and therefore peeling, cracking, etc. may occur when used as an adhesive. Moreover, the conductive resin composition of Patent Document 2 also has a high elastic modulus of the cured product, and is not suitable for the FHE field.
In this way, conventional connecting materials have a high elastic modulus when cured. It may interfere with the movement of people.

In addition, when adding electrical functions to wearable applications, heat-sensitive materials such as plastics and thermoplastic polyurethanes (TPU) are used as base materials, so conventional solders and thermosetting epoxy resins are used. In a connection method using a conductive adhesive, the base material itself may be damaged because it cannot withstand the melting point of the solder and the curing temperature of the conductive adhesive. Although the conductive adhesive of Patent Document 3 has flexibility, it has problems of a high curing temperature (about 185° C.) and a high resistance value. In addition, the conductive adhesive of Patent Document 4 has problems of a high curing temperature (200° C.×60 minutes) and a high resistance value.

Therefore, as a conductive connecting material for applications in the field of FHE, two important points are that it has flexible/stretchable properties (flexibility/elasticity) and that it can be processed at a low temperature.

In particular, wearable applications, which are one of the applications in the field of FHE, are required to be elastic (stretchable), and elastic conductive connection materials are required in order to follow the expansion and contraction.

On the other hand, ESL (Electrical Shelf Label) is one of the applications in the FHE field. ESL is expected to be used in a curved base material as one of its usage modes, so the conductive connecting material is also required to have flexibility.
Furthermore, in the FHE field, for example, as a conductive connecting material for ESL, the base material used is a heat-sensitive material such as plastic or thermoplastic polyurethane (TPU), so it can be dried at a low temperature of 70 ° C or less. Curing is required.

Therefore, in view of the above problems, the object of the present invention is a conductive resin for the FHE field, particularly a low-temperature drying type and highly stretchable conductive resin useful as a conductive connection material for wearable applications and ESL. The object is to provide a composition.

The conductive resin composition of one embodiment of the present invention has (A) a ratio of hard segments to soft segments (hard segments:soft segments) of 1:99 to 50:50 and a weight average molecular weight of 25,000. (B) an organic solvent having a boiling point of 155° C. to 205° C.; and (C) conductive particles.

In the conductive resin composition of the above embodiment, (A) the thermoplastic resin is a polystyrene-based resin, a polyolefin-based resin, a polyvinyl chloride-based resin, a polyurethane-based resin, a polyester-based resin, a polyamide-based resin, a polybutadiene-based resin, or any of these It is preferably at least one selected from hydrides and modified copolymer hydrides obtained by modifying hydrides.

In the conductive resin composition of the above embodiment, the mass ratio ((C):(A)) of (C) the conductive particles and (A) the thermoplastic resin is preferably 95:5 to 80:20.

In the above-described conductive resin composition, (C) the conductive particles preferably have an average particle size (D50) of 1 μm to 25 μm.

The conductive resin composition of the above embodiment preferably contains (C) silver particles having surface-treated conductive particles.

In the conductive resin composition of the above embodiment, it is preferable that the (C) ratio of the igross value to the BET value of the conductive particles (igross value/BET value) is 1.2 or more.

The conductive resin composition of the above form preferably further contains (D) a dispersant.

The conductive resin composition of the above embodiment preferably has a viscosity of 40 Pa·s to 200 Pa·s at 25° C. and 10 rpm with a rotary viscometer.

In the conductive resin composition of the above form, when the conductive resin composition is dried and cured under heating conditions of 70° C. for 30 minutes, the elongation of the cured product at room temperature is preferably 70% or more. is preferably 10×10 ⁻³ Ω·cm or less, and the amount of residual solvent in the cured product is preferably 25 parts by mass or less based on the total amount of the resin composition.

The conductive resin composition of the above form is suitable for FHE applications.

The conductive resin composition of the above form is preferably contained in a conductive adhesive, or cured to form a cured product.

It is preferable to equip a semiconductor device with the cured product of the conductive resin composition of the above-described form. Also, this cured product can be laminated on a substrate to form a laminate structure. This laminated structure is preferably used for electronic components.

INDUSTRIAL APPLICABILITY According to the present invention, it is possible to provide a conductive resin composition useful as a conductive material for the field of FHE, especially as a conductive material for wearable applications and ESL, which is dry at low temperature and has high stretchability. .

It is the figure which showed the test piece shape used for elongation measurement.

A conductive resin composition according to one embodiment of the present invention will be described below. However, the present invention is not limited to this embodiment.

<Conductive resin composition>
The conductive resin composition of one embodiment of the present invention (hereinafter referred to as the conductive resin composition) has (A) a ratio of hard segments and soft segments (hard segment:soft segment) of 1:99 to 50: 50 and a weight average molecular weight of 25,000 or more, (B) an organic solvent having a boiling point of 155° C. to 205° C., and (C) conductive particles.

<(A) Thermoplastic resin>
(A) The thermoplastic resin preferably has a hard segment to soft segment ratio (hard segment:soft segment) of 1:99 to 50:50.
By setting the content within this range, it is possible to impart appropriate flexibility to the present conductive resin composition. From this point of view, the ratio of hard segment:soft segment is more preferably 10:90 to 45:55, more preferably 30:70 to 40:60.

In the present invention, the hard segment (A) is a portion having rigidity in the thermoplastic resin and indicates a high glass transition temperature (Tg) segment. The soft segment (A) is a flexible portion in the thermoplastic resin and indicates a low glass transition temperature (Tg) segment. In particular, a block copolymer of a hard segment with a glass transition temperature (Tg) of less than 150°C and a soft segment with a glass transition temperature (Tg) of less than 0°C is more preferable. The glass transition point Tg is measured by differential scanning calorimetry (DSC).
The glass transition temperature (Tg) of the thermoplastic resin (A) as a whole is preferably -60°C to 120°C, more preferably -50°C to 100°C, and still more preferably -40°C to 80°C. By setting the content within this range, it is possible to impart appropriate flexibility to the present conductive resin composition.

(A) The thermoplastic resin is not particularly limited as long as it has a hard segment and a soft segment. Examples include polystyrene resins, polyolefin resins, polyvinyl chloride resins, polyurethane resins, polyester resins, and polyamide resins. , polybutadiene-based resins, hydrides thereof, and hydrides of modified copolymers obtained by modifying the hydrides.

More specifically, examples of polystyrene-based resins include polybutadiene, polyisoprene, and the like for soft segments and polystyrene for hard segments.
Examples of polyolefin-based resins include those using ethylene propylene rubber for the soft segment and polypropylene for the hard segment.
Examples of polyvinyl chloride-based resins include those using polyvinyl chloride for the soft segment and polyvinyl chloride for the hard segment.
Examples of polyurethane-based resins include those using polyether or polyester for the soft segment and polyurethane for the hard segment.
Examples of polyester-based resins include those using polyether for the soft segment and polyester for the hard segment.
Examples of polyamide-based resins include those using polypropylene glycol, polytetramethylene ether glycol, polyester or polyether for soft segments, and polyamide (nylon resin) for hard segments.
Examples of polybutadiene-based resins include those using amorphous butyl rubber for soft segments and syndiotactic 1,2-polybutadiene resin for hard segments.
These hydrides, modified copolymer hydrides obtained by modifying the hydrides, and the like can also be used.

(A) The thermoplastic resin preferably contains a polyurethane-based resin or a polyester-based resin as a main component.
In addition, the main component refers to the component that is blended in the thermoplastic resin (A) at the maximum ratio. % or more (including 100% by mass).

(A) The thermoplastic resin preferably has a weight average molecular weight of 25,000 or more. If the molecular weight of the thermoplastic resin is too low, the problem arises that the flexibility of the present conductive resin composition is low, which is not preferred.
On the other hand, if the molecular weight of the thermoplastic resin is too high, it will be necessary to increase the amount of solvent blended in order to achieve the desired viscosity. Problems can arise. Therefore, when the molecular weight of (A) the thermoplastic resin is within the above range, the viscosity, the elongation property, and the electric resistance value of the cured product can be appropriately balanced.
From this point of view, the weight average molecular weight of the thermoplastic resin (A) is more preferably 25,000 or more, even more preferably 30,000 or more, and particularly preferably 34,000 or more. Although the upper limit is not particularly limited, it is preferably 300,000 or less, more preferably 250,000 or less, and even more preferably 200,000 or less.

(A) Specific examples of thermoplastic resins include thermoplastic polyurethane elastomer "Milactran (registered trademark)" (manufactured by Nippon Miractran Co., Ltd.), hydrogenated styrene thermoplastic elastomer (SEBS) "Tuftec (registered trademark)" (Asahi Kasei Ltd.), saturated copolyester resin "Elytel (registered trademark)" (manufactured by Unitika Ltd.), and the like.

(A) thermoplastic resin, the ratio of (A) thermoplastic resin to the total of (A) thermoplastic resin and (C) conductive particles is preferably 5 parts by mass to 20 parts by mass, 7 It is more preferably from 7 parts by mass to 20 parts by mass, and even more preferably from 7 parts by mass to 18 parts by mass. By setting the content within this range, a cured product having flexibility/stretchability and good specific resistance can be obtained.

<(B) Organic solvent>
The (B) organic solvent dissolves the (A) thermoplastic resin, and preferably has a boiling point of 155°C to 205°C.
When the drying temperature is 155°C or higher, it becomes possible to dry the present conductive resin composition at a low temperature of 70°C or lower while maintaining workability. On the other hand, when it exceeds 205°C, the solvent cannot be sufficiently removed during heating for drying, and the drying property of the coating film may deteriorate. From this point of view, the boiling point of the (B) organic solvent is more preferably 155°C to 190°C, particularly preferably 155°C to 180°C.

(B) The organic solvent can be, for example, an amine-based solvent, an alcohol-based solvent, a ketone-based solvent, or the like, and two or more of them may be used in combination.

More specifically, the amine solvent includes diethylamine, triethylamine, propylamine, isopropylamine, dipropylamine, diisopropylamine, butylamine, isobutylamine, sec-butylamine, tert-butylamine, dibutylamine, diisobutylamine, tributylamine, pentylamine, dipentylamine, tripentylamine, 2-ethylhexylamine, allylamine, aniline, N-methylaniline, ethylenediamine, propylenediamine, diethylenetriamine, formamide, N-methylformamide, N,N-dimethylformamide, N,N-diethyl Formamide, acetamide, N-methylacetamide, N,N-dimethylacetamide, N-methylpropionamide, 2-pyrrolidone, N-methylpyrrolidone, ε-caprolactam, carbamic acid ester and the like can be mentioned.
Methanol, ethanol, isopropyl alcohol (IPA), benzyl alcohol and the like can be mentioned as alcohol solvents.
Ketone solvents include acetone, methyl ethyl ketone, 2-pentanone, 3-pentanone, 2-hexanone, methyl isobutyl ketone, 2-heptanone, 4-heptanone, diisobutyl ketone, acetonylacetone, mesityl oxide, phorone, isophorone, cyclohexanone, Methylcyclohexanone etc. can be mentioned.

Specific examples of organic solvents with a boiling point of 155 ° C. to 205 ° C. include anone (cyclohexanone) (manufactured by Nippon Alcohol Sales Co., Ltd.), DEDG (diethylene glycol diethyl ether) (manufactured by Toho Chemical Industry Co., Ltd.), acetophenone (Tokyo Chemical Industry Co., Ltd. ), EC (manufactured by Oxalis Chemicals Co., Ltd.), DBE (manufactured by INVISTA), EBA (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.), Shellsol MC311 (manufactured by Oxalis Chemicals Co., Ltd.), DIBK (manufactured by Sankyo Chemical Co., Ltd.) , Butyl cellosolve (manufactured by Daishin Chemical Co., Ltd.), 3-Methoxybutyl acetate (manufactured by Daicel Co., Ltd.), EEP (manufactured by Sankyo Chemical Co., Ltd.), Solfit (manufactured by Kuraray Co., Ltd.), Orthodichlorobenzene (manufactured by Kureha Co., Ltd.) ) and the like.

(B) The organic solvent is not particularly limited, but is preferably 100 parts by mass to 700 parts by mass, more preferably 150 parts by mass to 600 parts by mass, with respect to 100 parts by mass of the thermoplastic resin (A). Parts by mass to 400 parts by mass are more preferable. Within this range, the thermoplastic resin can be satisfactorily dissolved, and an excellent coating film can be formed even when dried at a low temperature of 70° C. or less.
The organic solvent (B) can be appropriately dissolved by using a weight of about four times the weight of the thermoplastic resin (A).
In addition, the organic solvent can be added as appropriate to the resin composition in order to adjust the viscosity of the resin composition.

<(C) Conductive particles>
(C) Conductive particles are used to impart conductivity and/or thermal conductivity to the present conductive resin composition. Although not particularly limited, the electrical conductivity is preferably 10<6> S/m or more. (C) Conductive particles include not only metal powder but also coated powder. A coated powder is a core (core particle) coated with a conductive substance. This core may be a non-conducting material.

(C) conductive particles, for example, gold, silver, nickel, copper, palladium, platinum, bismuth, tin, alloys thereof (especially bismuth-tin alloys, solder, etc.), aluminum, indium tin oxide, silver-coated Copper, silver-coated aluminum, metal-coated glass spheres, silver-coated fibers, silver-coated resins, antimony-doped tin, tin oxide, carbon fibers, graphite, carbon black and mixtures thereof.
Among them, considering electrical conductivity and thermal conductivity, preferably at least one selected from the group consisting of silver, nickel, copper, tin, aluminum, silver alloys, nickel alloys, copper alloys, tin alloys and aluminum alloys. Metal, more preferably at least one metal selected from the group consisting of silver, copper and nickel, more preferably silver or copper, most preferably silver.

(C) The shape of the conductive particles is not particularly limited, but may be spherical, amorphous, flake-like (scale-like), filament-like (needle-like), dendritic, or the like. Here, the flake shape refers to a shape having a ratio of “major axis/minor axis” (aspect ratio) of 2 or more, and includes plate-like shapes such as plate-like and scale-like shapes. (C) The major diameter and minor diameter of particles constituting the conductive particles can be obtained based on an image obtained from a scanning electron microscope (SEM) (n=20). The “major axis” refers to the longest diameter of the line segment passing through the approximate center of gravity of the particle in the particle image obtained by SEM, and the “minor axis” refers to the particle image obtained by SEM. , the shortest line segment passing through the center of gravity of the particle.
Note that the shape of the particles may be a combination of particles having different shapes.

(C) The conductive particles are not particularly limited, but preferably have a tap density of 1.5 g/cm ³ or more, more preferably 2.0 g/cm ³ to 6.0 g/cm ³ . Here, the tap density can be measured according to JIS Z 2512 metal powder-tap density measurement method.
If the tap density is too low, it will be difficult to disperse (C) the conductive particles in the cured product of the present conductive resin composition at a high density, and the conductivity of the cured product will tend to decrease. On the other hand, if the tap density is too high, separation and sedimentation of the (C) conductive particles tend to occur in the present conductive resin composition.

(C) The conductive particles preferably have an average particle size (D50) of 1 μm to 25 μm.
Within this range, the dispersibility of the (C) conductive particles in the present conductive resin composition is improved.
From such a point of view, it is more preferably 1 μm to 20 μm, further preferably 2 μm to 20 μm.
The average particle size (D50) refers to a particle size (median size) with a cumulative frequency of 50% in a volume-based particle size distribution measured by a laser diffraction method.

(C) The conductive particles preferably include surface-treated silver particles. By containing surface-treated silver particles, the electrical resistance of the conductive resin composition can be reduced, and the dispersibility of the particles can be improved.
The surface treatment can be done with liquid fatty acids, solid fatty acids or fatty amines.
Examples of liquid fatty acids include saturated fatty acids such as butyric acid, valeric acid, caproic acid, heptanoic acid, caprylic acid and pelargonic acid; Saturated fatty acids can be mentioned. These fatty acids may be used individually by 1 type, and may use 2 or more types together.
Examples of solid fatty acids include saturated fatty acids having 10 or more carbon atoms such as capric acid, palmitic acid and stearic acid, and unsaturated fatty acids such as crotonic acid and sorbic acid.
Examples of aliphatic amines include isobutylamine, octylamine, decylamine, dodecylamine, hexadecylamine, octadecylamine, oleylamine, 2-ethylhexyloxypropylamine and 3-lauryloxypropylamine.
Among them, the surface treatment with stearic acid or oleic acid is preferable.

(C) The conductive particles are not particularly limited, but preferably have a BET value (specific surface area) of 4.0 m ² /g or less. If the BET value (specific surface area) is too large, the viscosity becomes high when making a paste, and the handleability tends to deteriorate. On the other hand, when the BET value (specific surface area) is too small, the contact area between silver particles becomes small, resulting in a decrease in electrical conductivity.
From such a viewpoint, it is more preferably 0.1 m ² /g to 3.0 m ² /g, and even more preferably 0.1 m ² /g to 2.0 m ² /g.
The BET value (specific surface area) can be measured by the BET method.

(C) The conductive particles are not particularly limited, but preferably have an igross value (ignition loss) of 0.1% to 3.0%. If the igross value (loss on ignition) is too small, the dispersibility of the conductive particles will be poor. On the other hand, if the igross value (loss on ignition) is too large, contact between the Ag fillers becomes poor, and the specific resistance value of the cured product of the present conductive resin composition becomes poor.
From this point of view, the igross value (loss on ignition) is more preferably 0.15% to 2.0%, more preferably 0.15% to 1.5%.
The igross value (loss on ignition) indicates (C) the amount (% by mass) of the surface treatment agent present on the surface of the conductive particles, and (C) the conductive particles after firing at 800° C. for 30 minutes. It can be calculated from the mass of the residue.

(C) The conductive particles preferably have a ratio of igross value to BET value (igross value/BET value) of 1.2 to 6.0.
(C) When the ratio of the igross value to the BET value of the conductive particles is small, the amount of the surface treatment agent relative to the specific surface area is small, and (C) the dispersibility of the conductive particles is poor. If the dispersibility deteriorates, the dispersing time becomes long when dispersing in a solvent having a low boiling point, the residence time becomes long, and the volatilization amount of the solvent increases in (C) the step of dispersing the conductive particles. On the other hand, when the ratio of the igross value to the BET value of the (C) conductive particles is large, the amount of the surface treatment agent with respect to the specific surface area is large, and the contact between the Ag fillers of the (C) conductive particles is poor, resulting in the present conductivity. The specific resistance value of the cured product of the resin composition deteriorates.
From this point of view, the ratio of the egross value to the BET value is more preferably 1.2 to 5.0, more preferably 1.3 to 3.0.

(C) Specific examples of the conductive particles include flaky silver powder AGC-GS or AGC-B2 (both manufactured by Fukuda Metal Foil Powder Co., Ltd.), flaky silver powder FA618 (manufactured by DOWA Electronics Co., Ltd. ) and the like.

The (C) conductive particles have a mass ratio ((C):(A)) of (C) the conductive particles and (A) the thermoplastic resin in the conductive resin composition of 80:20 to 95: 5 is preferred.
Within this range, the electrical conductivity of the present conductive resin composition is improved.
From this point of view, the mass ratio ((C):(A)) is more preferably 80:20 to 92:8, more preferably 82:18 to 92:8.

<(D) Dispersant>
The conductive resin composition may contain (D) a dispersant.
As the (D) dispersant, for example, HYPERMER KD-57 (trade name) (manufactured by CRODA), which is an acidic dispersant, can be used.

<Other ingredients>
The present conductive resin composition may consist only of the components (A) to (C) or may consist of the components (A) to (D) only. Components such as surface treating agents, pigments, dyes, plasticizers, defoaming agents, defoaming agents, antioxidants, etc. may be contained as necessary.

<Physical property value>
When the present conductive resin composition is dried and cured under a heating condition of 70° C. for 30 minutes, the cured product preferably has an elongation of 70% or more at room temperature. The elongation percentage of the cured product is more preferably 75% or more, more preferably 90% or more.
The elongation rate can be adjusted by, for example, (A) the weight average molecular weight of the thermoplastic resin, the ratio of the hard segment and the soft segment, and the mass ratio of (A) the thermoplastic resin and (C) the conductive particles. .
In the present invention, normal temperature means preferably 0°C to 30°C, more preferably 10°C to 25°C.

The conductive resin composition preferably has a resistivity value of 10×10 ⁻³ Ω·cm or less when dried and cured under a heating condition of 70° C. for 30 minutes. The specific resistance value of the cured product is more preferably 5×10 ⁻³ Ω·cm or less, more preferably 1×10 ⁻³ Ω·cm or less.
The specific resistance value can be adjusted by, for example, (C) the particle shape and specific surface area of the conductive particles, and the mass ratio between (A) the thermoplastic resin and (C) the conductive particles.

When the present conductive resin composition is dried and cured under heating conditions of 70° C. for 30 minutes, the amount of residual solvent in the cured product is preferably 25 parts by mass or less with respect to the total amount of the resin composition (100 parts by mass). . The amount of residual solvent in the cured product is more preferably 20 parts by mass or less, more preferably 15 parts by mass or less, relative to the total amount (100 parts by mass) of the resin composition. By setting the amount of residual solvent within this range, the cured product of the present conductive resin composition can have a good specific resistance value. The amount of residual solvent can be adjusted by, for example, the boiling point of (B) the organic solvent.
Using TGDTA, the cured product of the resin composition is heated from 25 to 200° C. at a rate of 10° C./min, and the weight loss at 200° C. is defined as the residual solvent amount.

The present conductive resin composition preferably has a viscosity of 40 Pa·s to 200 Pa·s at 25° C. and 10 rpm with a rotary viscometer. By setting it as such a range, workability|operativity of this electroconductive resin composition can be made favorable. From such a viewpoint, the viscosity is more preferably 50 Pa s to 190 Pa s, and even more preferably 80 Pa s to 180 Pa s.

<Manufacturing method>
The present conductive resin composition is prepared by blending (A) a thermoplastic resin, (B) an organic solvent, (C) conductive particles, optionally (D) a dispersant, and other components and mixing them with stirring. can be manufactured.

A known device can be used to stir and mix these. For example, it can be mixed by a known device such as a hybrid mixer, a Henschel mixer, a roll mill, or a three-roll mill. These raw materials may be mixed at the same time, or a part of them may be mixed first and the rest of them may be mixed later.
The method for producing the present conductive resin composition is not particularly limited as long as each material is sufficiently kneaded.

<Supply method>
The conductive resin composition can be supplied by using a jet dispenser, an air dispenser, or the like. In addition, known coating methods (dip coating, spray coating, bar coater coating, gravure coating, reverse gravure coating, spin coater coating, etc.) and known printing methods (lithographic printing, carton printing, metal printing, offset printing, screen printing, gravure printing, flexographic printing, inkjet printing, etc.) can also be used.

<Curing conditions>
The conductive resin composition can be dried and cured by heating at a temperature of, for example, 40°C to 120°C. The heating temperature is preferably 50°C to 120°C, more preferably 70°C to 100°C. The heating time is, for example, preferably 0.1 to 3 hours, more preferably 0.5 to 2 hours.

In this specification, a product obtained by supplying a conductive resin composition in a predetermined pattern and drying it by heating at 70° C. for 30 minutes, for example, is referred to as a “cured product”.

<Application>
This conductive resin composition has elasticity and is excellent in low-temperature curability at 70° C. or lower. From such a point of view, for example, it can be used for the FHE field, and is useful for wearable applications, ESL, and the like.
This conductive resin composition can be used as a conductive adhesive by including it in an adhesive, or can be used as a cured product obtained by curing the present conductive resin composition as it is or by adding other components. The cured product also includes a cured product of a conductive adhesive.
The cured product can be provided in semiconductor devices such as sensors, capacitors, processors and memories, or can be laminated on a substrate such as an inorganic or organic substrate used for an electric circuit board to form a laminated structure. This laminated structure can be used for ESL or the like.

A conductive resin composition according to one embodiment of the present invention will be described below. However, the present invention is not limited to this example.

The following materials were used in producing the conductive resin compositions of Examples and Comparative Examples. H/S represents the ratio of the hard segment to the soft segment (hard segment/soft segment).
<Material>
1. (A) Thermoplastic resin (A1) Urethane resin (Product number: P22SRAT Nippon Miractran Co., Ltd.)
H/S = 34/66, weight average molecular weight Mw 120,000 to 180,000
Glass transition temperature (Tg): -40°C
(A2) SEBS (Product number: H1221 Asahi Kasei Corporation)
H/S = 12/88, weight average molecular weight Mw 147,600
Glass transition temperature (Tg): -25°C
(A3) Polyester resin (Product number: UE-3510 Unitika Ltd.)
H/S = 50/50, weight average molecular weight Mw 34,000
Glass transition temperature (Tg): -25°C
(A4) Polyester resin (Product number: UE-3400 Unitika Ltd.)
H/S = 35/65, weight average molecular weight Mw 25,000
Glass transition temperature (Tg): -20°C
(A5) Polyester resin (Product number: UE-3220 Unitika Ltd.)
H/S = 35/65, weight average molecular weight Mw 25,000
Glass transition temperature (Tg): 5°C
(A6) Polyamide resin (Product number: PA66-1 Asahi Kasei Co., Ltd.)
H/S = 77.45/22.55, weight average molecular weight Mw 26,000
Glass transition temperature (Tg): 60°C
(A7) Styrene maleic anhydride copolymer (product number: SMA1000 SARTOMER)
H/S = 50/50, weight average molecular weight Mw 5,500
Glass transition temperature (Tg): 155°C

(B) Organic solvent (B1) Anone (cyclohexanone) (Japan Alcohol Sales Co., Ltd.)
Boiling point 156°C
(B2) Diethylene glycol diethyl ether (Toho Chemical Industry Co., Ltd.)
Boiling point 180-190°C
(B3) Acetophenone (methyl phenyl ketone) (Tokyo Chemical Industry Co., Ltd.)
Boiling point 202°C
(B4) Butyl acetate (Fujifilm Wako Pure Chemical Industries, Ltd.)
Boiling point 126°C
(B5) 3-methoxy-N,N-dimethylpropanamide boiling point 215°C

(C) Conductive particles (C1) Flake-like silver powder / surface treatment agent: stearic acid (product number: AGC-GS Fukuda Metal Foil Powder Co., Ltd.)
Average particle diameter (D50) 12.48 μm, tap density 3.23 g/cm ³ , BET value 0.285 g/m ² , igross value 0.52%, igross value/BET value 1.825
(C2) Flake-like silver powder/surface treatment agent: stearic acid (product number: FA618 DOWA Electronics Co., Ltd.)
Average particle size (D50) 7.25 μm, tap density 4.03 g/cm ³ , BET value 0.491 g/m ² , igross value 0.79%, igross value/BET value 1.609
(C3) Flake-like silver powder/surface treatment agent: stearic acid (product number: AGC-B2, Fukuda Metal Foil Powder Co., Ltd.)
Average particle diameter (D50) 6.838 μm, tap density 4.29 g/cm ³ , BET value 0.788 g/m ² , igross value 0.57%, igross value/BET value 0.723

(D) dispersant (D1) acidic dispersant (CRODA)

<Production of Examples and Comparative Examples>
Each material is blended so that the mass ratio shown in Table 1 or 2 below is obtained, and mixed with stirring using a three-roll mill to produce conductive resin compositions of Examples 1 to 15 and Comparative Examples 1 to 4. bottom.

(physical property value)
Methods for measuring and evaluating physical property values in Examples and Comparative Examples are shown below.

(Solvent solubility)
After heating each organic solvent to 60°C, each thermoplastic resin is weighed and dissolved while stirring with a laboratory stirrer. Visually check if it dissolves every hour, and after stirring for a total of 3 hours, if there is no dissolved matter remaining (if there is no residue), "○" If any), it was evaluated as "x".

(dryness)
A cured product obtained by drying and curing each conductive resin composition under heating conditions of 70 ° C. for 30 minutes is heated to 25 to 200 ° C. at a rate of 10 ° C./min using TGDTA, and the mass loss at 200 ° C. remains. As the amount of solvent, the value was used to confirm the drying property.
A test piece with a residual solvent amount of 25 parts by mass or less with respect to the total amount of the conductive resin composition is "O", a test piece with 26 parts by mass or more is "X", and a test piece that could not be evaluated itself is "- ” was evaluated. Whether or not the resin is cured at 70° C. can be expressed by the die shear strength, which will be described later.

(viscosity)
The viscosity of each conductive resin composition was measured at 10 rpm using a Brookfield RVT viscometer (spindle: SC4-14 spindle, measurement temperature: 25° C.). In Comparative Example 3, measurement was not possible.
200 (Pa·s) or less was evaluated as acceptable.

(die shear strength)
A glass substrate was prepared as the substrate, and a Si die of 3 mm square was prepared as the die. Using a polyimide film stencil (thickness: 120 μm) with holes of φ2 mm, each conductive resin composition was printed on a glass substrate. After that, a 3 mm square Si die was mounted and cured in an air convention oven at 70° C. for 30 minutes to prepare a sample for die shear strength measurement. Die shear strength was measured at room temperature using a Nordson DAGE tabletop strength tester (Model: 4000PLUS-CART-S200KG).
For each conductive resin composition, 10 die shear strength measurement samples were measured, and the arithmetic average value was taken as the die shear strength. In Comparative Example 3, measurement was not possible.
0.5 (N/mm ² ) or more was evaluated as acceptable.

(dispersibility)
When the particle size of the resin composition was measured with a grind gauge in accordance with JIS K5400'-1990 filament method, the presence or absence of aggregates was visually confirmed. If the average particle size (D50) is 10 times or more than the average particle size (D50) of the compounded (C) conductive particles, "x" is displayed, and if it is 4 times or more and less than 10 times, "△" is displayed, and 4 times When less than was shown, it was set as "〇".

(Resistivity)
On a glass substrate, two tapes with a thickness of about 85 to 95 μm are pasted in parallel at intervals of 3 mm, and between the two tapes, width: 3 mm × length: 50 mm × thickness: about 90 μm each conductive After printing the resin composition film, it was cured in an Air convention oven at 70° C. for 30 minutes. After measuring the film thickness of each conductive resin composition film after curing, the resistance value was measured by the 4-probe method to obtain the specific resistance. In Comparative Example 3, measurement was not possible. "OverFlow" of Comparative Example 4 was in a state where the resistance value was too large and exceeded the measurement range.
A resistance of 20×10 ⁻⁴ Ω·cm or less was evaluated as acceptable.

(Growth rate)
The elongation was measured using INSTRON's universal material testing machine Model 5566 (measurement conditions: tensile speed = 5 mm/min). The elongation rate was defined as the amount of strain until the test piece broke in a stress-strain curve (hereinafter referred to as SS curve) obtained from a tensile tester. FIG. 1 shows the shape of the test piece used for elongation measurement. For example, when the elongation rate is described as "70%" in the examples, the test piece breaks when the elongation rate is 70%. Moreover, those described as ">100%" in the examples indicate those that did not break even when the elongation rate exceeded 100%.

Comparative Examples 1 and 2 did not satisfy the elongation criteria. Comparative Example 1 had a high proportion of (A) the hard segment of the thermoplastic resin. In Comparative Example 2, (A) the thermoplastic resin had a low weight average molecular weight.
Comparative Example 3 did not meet the acceptance criteria because the dryness, viscosity, die shear strength, dispersibility, specific resistance, and elongation rate could not be measured. In Comparative Example 3, the boiling point of the organic solvent (B) was as low as 126° C., and the drying property was too fast to form a paste.
In Comparative Example 4, the dryness did not satisfy the acceptance criteria, and the specific resistance was Overflow, so it could not be measured. In Comparative Example 4, the boiling point of the (B) organic solvent was as high as 215°C.

From these results, (A) a thermoplastic resin having a hard segment to soft segment ratio (hard segment: soft segment) of 1:99 to 50:50 and a weight average molecular weight of 25,000 or more, ( It was found that a conductive resin composition containing B) an organic solvent having a boiling point of 155° C. to 205° C. and (C) conductive particles is low-temperature drying and highly stretchable.

Claims (17)

(A) a thermoplastic resin having a hard segment to soft segment ratio (hard segment: soft segment) of 1:99 to 50:50 and a weight average molecular weight of 25,000 or more;
(B) an organic solvent having a boiling point of 155°C to 205°C;
(C) conductive particles;
A conductive resin composition comprising: The thermoplastic resin (A) is a polystyrene resin, a polyolefin resin, a polyvinyl chloride resin, a polyurethane resin, a polyester resin, a polyamide resin, a polybutadiene resin, a hydride thereof, or a modified hydride. 2. The conductive resin composition according to claim 1, which is at least one selected from hydrogenated copolymers. 3. The conductive resin composition according to claim 1, wherein the mass ratio ((C):(A)) between the (C) conductive particles and the (A) thermoplastic resin is 95:5 to 80:20. thing. The conductive resin composition according to any one of claims 1 to 3, wherein the (C) conductive particles have an average particle size (D50) of 1 µm to 25 µm. The conductive resin composition according to any one of claims 1 to 4, wherein the (C) conductive particles comprise surface-treated silver particles. 6. The conductive resin composition according to any one of claims 1 to 5, wherein the (C) conductive particles have a ratio of egross value to BET value (igross value/BET value) of 1.2 or more. The conductive resin composition according to any one of claims 1 to 6, further comprising (D) a dispersant. The conductive resin composition according to any one of claims 1 to 7, which has a viscosity of 40 Pa·s to 200 Pa·s at 25°C and 10 rpm with a rotary viscometer. The conductivity according to any one of claims 1 to 8, wherein the conductive resin composition is dried and cured under heating conditions of 70 ° C. for 30 minutes, and the elongation rate at room temperature of the cured product is 70% or more. Resin composition. The conductive resin composition according to any one of claims 1 to 8, wherein the cured product has a specific resistance value of 10 × 10 ^-3 Ω·cm or less when dried and cured under a heating condition of 70°C for 30 minutes. The conductive resin composition described. 9. Any one of claims 1 to 8, wherein the amount of residual solvent in the cured product obtained by drying and curing the conductive resin composition under heating conditions of 70° C. for 30 minutes is 25 parts by mass or less with respect to the total amount of the conductive resin composition. 1. The conductive resin composition according to claim 1. The conductive resin composition according to any one of claims 1 to 11, which is used for flexible hybrid electronics. A conductive adhesive comprising the conductive resin composition according to any one of claims 1 to 11. A cured product obtained by curing the conductive resin composition according to any one of claims 1 to 11. A semiconductor device comprising the cured product according to claim 14 . A laminate structure in which the cured product according to claim 14 is laminated on a substrate. An electronic component using the laminated structure according to claim 16 .

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