CN110914370B

CN110914370B - Carbon nanotube-containing composition and method for producing thermally cured product of carbon nanotube-containing composition

Info

Publication number: CN110914370B
Application number: CN201980003598.0A
Authority: CN
Inventors: 森田稔
Original assignee: Furukawa Electric Co Ltd
Current assignee: Furukawa Electric Co Ltd
Priority date: 2018-06-20
Filing date: 2019-04-25
Publication date: 2022-02-11
Anticipated expiration: 2039-04-25
Also published as: TWI770393B; WO2019244479A1; KR102291539B1; JP7247098B2; JPWO2019244479A1; TW202000787A; KR20200027507A; CN110914370A

Abstract

The purpose of the present invention is to provide a composition that can be used as a conductive member for conduction inspection that can perform conduction inspection even when wiring of a circuit device to be inspected is narrowed in pitch and wiring is thinned, that has excellent conductivity, and that does not contain a metal component as a conductive material, and a method for producing a thermally cured product of the composition. A carbon nanotube-containing composition comprising (A) carbon nanotubes, (B) an organic solvent and (C) a thermosetting resin, wherein the absolute value of the difference between the boiling point (T1) of the organic solvent (B) and the thermosetting reaction initiation temperature (T2) of the thermosetting resin (C) is 70 ℃ or less.

Description

Carbon nanotube-containing composition and method for producing thermally cured product of carbon nanotube-containing composition

Technical Field

The present invention relates to a composition that is used as, for example, a conductive member for conduction test that can be electrically connected to an electrode to be tested of a circuit device to perform conduction test of the electrode to be tested and does not contain a metal component as a conductive material, and a method for producing a thermally cured product thereof.

Background

Conventionally, an electrical connector called a contact probe is used to confirm normal conduction of wiring of a semiconductor package or the like. In recent years, with the miniaturization of electronic components such as semiconductors, the pitch of wiring in semiconductor packages and the like has been narrowed, and the wiring has been made thinner. This also requires miniaturization of the contact probe. However, the contact probe is a precision mechanical component including a spring, a metal capillary, and the like, and there is a limitation in miniaturization thereof. Therefore, as the pitch of wiring in semiconductor packages and the like becomes narrower, conductive members for conduction inspection such as anisotropic conductive sheets are sometimes used instead of contact probes as electrical connectors.

As the conductive member for conduction test such as the anisotropic conductive sheet, for example, an anisotropic conductive sheet obtained as follows is proposed: in a sheet-like member, a plurality of chips (core sheets) are formed, each of the chips including a plurality of metal wires arranged in parallel on the same plane, two or more chips are laminated to form a laminate in a state in which the direction of the metal wire included in one chip is substantially aligned with the direction of the metal wire included in another chip, and the laminate is cut in a direction substantially perpendicular to the longitudinal direction of the metal wire, thereby obtaining an anisotropic conductive sheet (patent document 1).

However, in the conductive member for conduction check of patent document 1, in order to cope with the narrowing of the pitch of the wirings in the semiconductor package and the like, the interval between the metal lines arranged in parallel needs to be narrowed accordingly. However, if the interval between the metal lines is set to be narrow, the metal lines may contact each other. Therefore, the conductive member for conduction check of patent document 1 still has a limitation in order to cope with the narrowing of the pitch of the wiring in the semiconductor package and the like.

As another example of the conductive member for conduction test, there is proposed an anisotropic conductive sheet including: an insulating sheet body made of an elastic polymer substance and having a plurality of through holes formed therein; and a conductive path forming portion formed in the plurality of through holes and formed by containing a conductive material in an elastic polymer substance (patent document 2). As the conductive material contained in the elastic polymer substance, conductive metal particles are used.

However, in the conductive member for conduction test of patent document 2, in order to cope with the narrowing pitch of the wiring of the semiconductor package and the like, it is necessary to reduce the width of the through hole filled with the elastic polymer substance containing the conductive particles, and therefore, it is necessary to use small conductive particles having uniform particle diameters as the conductive particles. As a result, the conductive particles are likely to aggregate, and it is difficult to uniformly fill the through-holes with the conductive particles, resulting in a problem that sufficient conductivity cannot be obtained.

In patent documents 1 and 2, a metal material is used to impart conductivity to the conductive member for conduction test. When a metal material is used for the conductive member for conduction test, there is a problem that an electrode or a circuit device to be tested is contaminated with the metal material. Therefore, there is a demand for the development of a conductive member for conduction test that does not use a metal component as a conductive material.

Documents of the prior art

Patent document

Patent document 1: japanese patent No. 6026321

Patent document 2: japanese patent No. 5018612

Disclosure of Invention

Problems to be solved by the invention

In view of the above circumstances, an object of the present invention is to provide a composition that can be used as a conductive member for conduction test that can perform conduction test even when wiring of a circuit device to be tested is narrowed in pitch and wiring is thinned, that has excellent conductivity, and that does not contain a metal component as a conductive material, and a method for producing a thermally cured product of the composition.

Means for solving the problems

In order to solve the above problems, a composition containing carbon nanotubes is provided. The gist of the configuration of the present invention is as follows.

[1] A carbon nanotube-containing composition comprising (A) carbon nanotubes, (B) an organic solvent and (C) a thermosetting resin,

the absolute value of the difference between the boiling point (T1) of the organic solvent (B) and the thermosetting reaction initiation temperature (T2) of the thermosetting resin (C) is 70 ℃ or lower.

[2] The carbon nanotube-containing composition according to [1], wherein the intensity ratio G/D of a G band to a D band in a Raman spectrum obtained by Raman spectroscopy of the carbon nanotube (A) is 1.0 or more, and the average length of the carbon nanotube (A) is 1.0 μm or more.

[3] The composition comprising carbon nanotubes according to [1] or [2], wherein the thermosetting resin (C) is an epoxy resin.

[4] The carbon nanotube-containing composition according to any one of [1] to [3], wherein the carbon nanotube (A) is contained in an amount of 0.1 to 15 mass% based on 100 mass% of the total solid content of the carbon nanotube-containing composition.

[5] A thermally cured product of the carbon nanotube-containing composition according to any one of [1] to [4 ].

[6] The thermal cured product according to [5], wherein the volume resistivity is 0.1. omega. cm or less.

[7] A method for producing a thermally cured product of a carbon nanotube-containing composition, comprising the steps of:

a step of applying a carbon nanotube-containing composition onto a film, the carbon nanotube-containing composition comprising (A) carbon nanotubes, (B) an organic solvent, and (C) a thermosetting resin, wherein the absolute value of the difference between the boiling point (T1) of the organic solvent (B) and the thermosetting reaction initiation temperature (T2) of the thermosetting resin (C) is 70 ℃ or less; and

and (C) a step of volatilizing the organic solvent (B) and initiating a thermosetting reaction of the thermosetting resin (C) by heat-treating the composition containing carbon nanotubes.

[8] The production method according to [7], wherein the thermally cured product constitutes a conductive sheet having a thickness of 1 μm to 500 μm.

In the composition of the present invention, carbon nanotubes are used as a conductive material, not a metal component. Therefore, in the composition of the present invention, a metal component is not compounded as a conductive material. In the present specification, the "thermosetting reaction initiation temperature (T2)" refers to a temperature measured as follows. The thermosetting resin was charged into a sample container of a Differential Scanning Calorimeter (DSC) to prepare a closed container, and the temperature was raised from room temperature to 300 ℃ at a temperature rise rate of 5 ℃/min under a nitrogen atmosphere, and the curing heat release behavior was shown by DSC measurement chart, thereby obtaining the reaction initiation temperature. As shown in fig. 1, the degree of increase of the exothermic peak of curing (DSC onset) was determined from the obtained DSC chart and was taken as the thermal curing reaction initiation temperature (T2).

ADVANTAGEOUS EFFECTS OF INVENTION

The carbon nanotubes have a property of decreasing characteristics such as conductivity when aggregated, that is, dispersibility is decreased. On the other hand, according to the mode of the composition of the present invention, the carbon nanotubes and the organic solvent as a dispersion medium of the thermosetting resin are compounded, and the absolute value of the difference between the boiling point (T1) of the organic solvent and the thermosetting reaction initiation temperature (T2) of the thermosetting resin is suppressed to 70 ℃ or less, so that the volatilization of the organic solvent is synchronized with the thermosetting of the thermosetting resin at the time of the thermosetting treatment of the composition. Thus, even when the composition of the present invention is subjected to a heat curing treatment, the dispersibility of the carbon nanotubes in the heat cured product can be maintained in an excellent state. Therefore, by heat curing the composition of the present invention in a predetermined form, it is possible to obtain a conductive member for conduction test excellent in conductivity, which can suitably perform conduction test even when the wiring of the circuit device to be tested is narrowed in pitch and the wiring is thinned.

In addition, according to the embodiment of the composition of the present invention, by using the carbon nanotube as a conductive material instead of the metal component, it is possible to prevent the electrode or the circuit device to be inspected from being contaminated with the metal material at the time of the conduction inspection.

According to the embodiment of the composition of the present invention, the electrical conductivity of the thermoset product of the composition can be further improved by setting the intensity ratio G/D of the G band to the D band of the raman spectrum of the carbon nanotube to 1.0 or more and the average length of the carbon nanotube to 1.0 μm or more.

According to the aspect of the composition of the present invention, by including 0.1 mass% or more and 15 mass% or less of carbon nanotubes in 100 mass% of the total solid content included in the composition, excellent conductivity and excellent dispersibility of carbon nanotubes can be imparted to a thermoset product, and good moldability can be obtained.

Drawings

FIG. 1 is a view for explaining a method of measuring a thermosetting reaction initiation temperature.

Detailed Description

The following will describe in detail the composition containing carbon nanotubes as the composition of the present invention. The composition of the present invention is a carbon nanotube-containing composition comprising (A) carbon nanotubes, (B) an organic solvent, and (C) a thermosetting resin, wherein the absolute value of the difference between the boiling point (T1) of the organic solvent (B) and the thermosetting reaction initiation temperature (T2) of the thermosetting resin (C) is 70 ℃ or less.

(carbon nanotubes)

The carbon nanotube is not particularly limited, and a known carbon nanotube can be used. Specifically, for example, there are single-walled carbon nanotubes in which 1 surface of graphite is rolled up into 1 layer, and multi-walled carbon nanotubes in which a plurality of layers are rolled up. In the carbon nanotube-containing composition of the present invention, the diameter (fiber diameter) and average length of the carbon nanotubes are not particularly limited, and carbon nanotubes having an average length are preferably used, and in particular, single-walled carbon nanotubes having an average length are preferably used, from the viewpoints of conductivity, moldability, and the like. If necessary, a single-walled carbon nanotube and a multi-walled carbon nanotube may be used in combination.

From the viewpoint of further improving the conductivity, the lower limit of the average length of the single-walled carbon nanotubes is preferably 1.0 μm, more preferably 5.0 μm, and particularly preferably 10 μm. On the other hand, the upper limit of the average length of the single-walled carbon nanotubes is preferably 200 μm, more preferably 150 μm, and particularly preferably 100 μm, from the viewpoint of preventing the surface appearance from deteriorating when the single-walled carbon nanotubes are formed into a molded product or a film.

The lower limit of the diameter of the single-walled carbon nanotube is preferably 0.5nm, and particularly preferably 1.0nm, from the viewpoint of suppressing aggregation when dispersed in a thermosetting resin and an organic solvent. On the other hand, the upper limit of the diameter of the single-walled carbon nanotube is preferably 15nm, and particularly preferably 10nm, from the viewpoint of improving mechanical properties due to the nano effect.

The length-thickness ratio of the single-walled carbon nanotube is not particularly limited, and may be appropriately selected from the viewpoint of conductivity, dispersibility, and the like. Among them, the lower limit of the length-thickness ratio of the single-walled carbon nanotube is preferably 1000, and particularly preferably 5000, in view of ensuring conductivity with a small number of electrical contacts and enabling formation of a high-dimensional electrical network by increasing the number of electrical contacts with other carbon nanotubes in one carbon nanotube. On the other hand, the upper limit of the length-thickness ratio of the single-walled carbon nanotube is preferably 200000, and particularly preferably 100000, from the viewpoint of obtaining excellent dispersibility in an organic solvent and a thermosetting resin.

The intensity ratio G/D of the G band to the D band (hereinafter, sometimes referred to as "G/D band ratio") of the raman spectrum obtained by raman spectroscopy of the single-walled carbon nanotube is not particularly limited, and the lower limit value of the G/D band ratio is preferably 1.0, more preferably 4.0, and particularly preferably 6.0, from the viewpoint of further improving the conductivity. On the other hand, the higher the upper limit of the G/D band ratio, the more preferable is, for example, 100. Here, the G band is 1590cm in Raman spectrum^-1Raman shift observed nearby, from graphite. D band is 1350cm in Raman spectrum^-1The raman shift observed nearby is derived from defects of amorphous carbon and graphite. That is, the higher the ratio of the peak heights of the G band and the D band, that is, the higher the G/D ratio, the higher the linearity and the crystallinity, and the higher the quality. In addition, in the case of solid raman spectroscopy, the measurement value may be deviated by sampling. Therefore, the G/D band ratio was measured by Raman spectroscopy for at least 3 different sites, and the arithmetic mean value thereof was defined as the G/D band ratio in the present specification.

The multilayered carbon nanotube may be a 2-layered carbon nanotube (DWNT) or a multilayered carbon nanotube (MWNT) having 3 or more layers. Similarly to the single-walled carbon nanotubes, the lower limit of the average length of the multi-walled carbon nanotubes is preferably 1.0 μm, more preferably 5.0 μm, and particularly preferably 10 μm, from the viewpoint of further improving the electrical conductivity. On the other hand, as with the single-walled carbon nanotubes, the upper limit of the average length of the multi-walled carbon nanotubes is preferably 200 μm, more preferably 150 μm, and particularly preferably 100 μm, in order to prevent deterioration of the surface appearance when formed into a molded product or film.

The lower limit of the diameter of the multilayered carbon nanotube is preferably 0.5nm, and particularly preferably 1.0nm, from the viewpoint of suppressing aggregation when dispersed in a thermosetting resin and an organic solvent, as in the case of the single-layered carbon nanotube. On the other hand, as with the single-walled carbon nanotubes, the upper limit of the diameter of the multi-walled carbon nanotubes is preferably 15nm, and particularly preferably 10nm, from the viewpoint of improving mechanical properties due to the nano effect.

The length-thickness ratio of the multilayered carbon nanotube is not particularly limited, and may be appropriately selected from the viewpoint of conductivity, dispersibility, and the like. Among these, the lower limit of the length-thickness ratio of the multilayered carbon nanotube is preferably 1000, and particularly preferably 5000, from the viewpoint that conductivity is ensured with a small number of electrical contacts, and a high-dimensional electrical network can be formed with an increased number of electrical contacts with other carbon nanotubes in one carbon nanotube, as in the case of the single-walled carbon nanotube. On the other hand, as with the single-walled carbon nanotubes, the upper limit of the length-thickness ratio of the multi-walled carbon nanotubes is preferably 200000, and particularly preferably 100000, from the viewpoint of obtaining excellent dispersibility in organic solvents and thermosetting resins.

The G/D band ratio of the multi-walled carbon nanotube is not particularly limited, and the lower limit of the G/D band ratio is preferably 1.0, more preferably 4.0, and particularly preferably 6.0, from the viewpoint of further improving the conductivity, as in the single-walled carbon nanotube. On the other hand, as in the single-walled carbon nanotube, the higher the upper limit of the G/D band ratio, the more preferable is, for example, 100.

The content of the carbon nanotubes is not particularly limited, and the lower limit thereof is preferably 0.1 mass%, more preferably 1.0 mass%, further preferably 3.0 mass%, and particularly preferably 5.0 mass% of the total solid content 100 mass% of the carbon nanotube-containing composition, from the viewpoint of imparting excellent conductivity having a volume resistivity of 0.1 Ω · cm or less to the thermoset product. On the other hand, the upper limit of the content of the carbon nanotubes is preferably 15 mass% of the total solid content of the carbon nanotube-containing composition in terms of obtaining excellent dispersibility of the carbon nanotubes in the thermally cured product, and is more preferably 12 mass%, even more preferably 10 mass%, and particularly preferably 7.0 mass% of the total solid content of the carbon nanotube-containing composition in terms of easily obtaining a thermally cured product which can be easily molded into a sheet shape and has an excellent electrical conductivity in a sheet shape. The term "total solid content" refers to a component obtained by removing volatile components such as an organic solvent from a composition containing carbon nanotubes.

The BET specific surface area of the carbon nanotube is not particularly limited, but is preferably 600m in view of electrical conductivity²More than g. The "BET specific surface area" refers to a nitrogen adsorption specific surface area measured by a BET method.

(organic solvent)

The organic solvent is mixed as a dispersion medium of the carbon nanotubes and a thermosetting resin described later. In the composition of the present invention, the kind of the organic solvent is selected so that the absolute value of the difference between the boiling point (T1) of the organic solvent and the heat curing reaction initiation temperature (T2) of the thermosetting resin described later is 70 ℃ or lower. Therefore, the kind of the organic solvent is selected so that the boiling point (T1) of the organic solvent is in the range of T2 to 70 ℃ C. T1 to T2+70 ℃ C, depending on the value of the heat curing reaction initiation temperature (T2) of the thermosetting resin to be compounded.

By suppressing the absolute value of the difference between the boiling point (T1) of the organic solvent and the thermosetting reaction initiation temperature (T2) of the thermosetting resin to 70 ℃ or less, the volatilization of the organic solvent is synchronized with the thermosetting of the thermosetting resin at the time of the thermosetting treatment of the carbon nanotube-containing composition. Thus, even when the carbon nanotube-containing composition of the present invention is subjected to a heat curing treatment, the dispersibility of the carbon nanotubes in the heat cured product can be maintained in an excellent state. Therefore, by subjecting the carbon nanotube-containing composition of the present invention to a thermosetting treatment, the conductivity of the whole of the thermoset product can be made uniform, and excellent conductivity having a volume resistivity of 0.1 Ω · cm or less can be obtained, and therefore, a conductive member for conduction check that can appropriately perform conduction check even when the wiring of the circuit device to be checked is narrowed in pitch and the wiring is thinned can be obtained.

When the absolute value of the difference between the boiling point (T1) of the organic solvent and the thermosetting reaction initiation temperature (T2) of the thermosetting resin is 70 ℃ or less, the boiling point (T1) of the organic solvent and the thermosetting reaction initiation temperature (T2) of the thermosetting resin are not particularly limited, and it is preferable that the boiling point (T1) of the organic solvent is higher than the thermosetting reaction initiation temperature (T2) of the thermosetting resin from the viewpoint of further improving the dispersibility of the carbon nanotubes in the thermally cured product. The absolute value of the difference between the boiling point (T1) of the organic solvent and the thermosetting reaction initiation temperature (T2) of the thermosetting resin is not particularly limited, and is preferably 70 ℃ or lower.

The content of the organic solvent in the carbon nanotube-containing composition is not particularly limited, and is preferably 80 mass% or more and 98 mass% or less, and particularly preferably 85 mass% or more and 95 mass% or less in the carbon nanotube-containing composition.

(thermosetting resin)

The thermosetting resin functions as a binder resin. Examples of the thermosetting resin include epoxy resins, phenol resins, amino resins, unsaturated polyester resins, polyurethane resins, silicone resins, and thermosetting polyimide resins. The thermosetting resin may be used alone, or two or more kinds may be used in combination. Among these thermosetting resins, epoxy resins and silicone resins are particularly preferable.

Examples of the epoxy resin include a bifunctional epoxy resin or a polyfunctional epoxy resin such as a bisphenol a type epoxy resin, a bisphenol F type epoxy resin, a bisphenol S type epoxy resin, a brominated bisphenol a type epoxy resin, a hydrogenated bisphenol a type epoxy resin, a bisphenol AF type epoxy resin, a biphenyl type epoxy resin, a naphthalene type epoxy resin, a fluorene type epoxy resin, a phenol novolac type epoxy resin, a cresol novolac type epoxy resin, a trishydroxyphenylmethane type epoxy resin, a tetrahydroxyphenylethane type epoxy resin, a biphenylaralkyl type epoxy resin, a phenylalkyl type epoxy resin, a dicyclopentadiene type epoxy resin, and the like, and a hydantoin type epoxy resin, a triglycidyl isocyanurate type epoxy resin, a glycidyl amine type epoxy resin, a glycidyl ester type epoxy resin, and the like.

The content of the thermosetting resin in the carbon nanotube-containing composition is not particularly limited, and the thermosetting resin is preferably contained so that the total content of the thermosetting resin and the carbon nanotube is 2 mass% or more and 20 mass% or less in the carbon nanotube-containing composition, and particularly preferably contained so that the content is 5 mass% or more and 15 mass% or less.

In the case of using an epoxy resin as the thermosetting resin, a curing agent (epoxy resin curing agent) may be used. Examples of the epoxy resin curing agent include known curing agents such as amines, acid anhydrides, and polyhydric phenols, and a latent curing agent which exhibits curability at a predetermined temperature equal to or higher than room temperature and also exhibits rapid curability is preferable. As the latent curing agent, dicyandiamide, imidazoles, hydrazides, boron trifluoride-amine complexes, amineimides, polyamine salts, and modifications thereof, and microcapsule-type substances can be used. These may be used alone or in combination of two or more. The content of the epoxy resin curing agent is not particularly limited, and may be, for example, 0.5 to 50 parts by mass with respect to 100 parts by mass of the epoxy resin.

In addition, in the case of using a silicone resin as the thermosetting resin, a curing agent (silicone resin curing agent) may be used. Examples of the silicone resin curing agent include alkoxysilane compounds. Examples of the alkoxysilane compound include silane compounds having an alkoxy group such as a methoxy group, an ethoxy group, or a propoxy group, and specific examples thereof include methyltrimethoxysilane, methyltriethoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, tetraethoxysilane, glycidoxypropyltrimethoxysilane, and the like. These may be used alone or in combination of two or more. The content of the silicone resin curing agent is not particularly limited, and for example, may be 1.0 part by mass or more and 100 parts by mass or less with respect to 100 parts by mass of the silicone resin.

The carbon nanotube-containing composition of the present invention may further contain, in addition to the above components, an isocyanate-based, epoxy-based, melamine-based, peroxide-based crosslinking agent, a silane coupling agent, a dispersing agent such as a surfactant, a conductive filler (filler), a flame retardant, an ion scavenger, a thickener, an antioxidant, and the like, as required.

Next, a method for producing the carbon nanotube-containing composition of the present invention will be described. The method for producing the carbon nanotube-containing composition of the present invention is not particularly limited, and for example, the carbon nanotubes are first dispersed in an organic solvent to obtain organic solvent-dispersed carbon nanotubes. The method for dispersing the carbon nanotubes in the organic solvent is not particularly limited, and examples thereof include a homogenizer, a thin film rotary mill, a jaw mill, an automatic mortar mill, an ultracentrifugal mill, a jet mill, a cutter mill, a disk mill, a ball mill, a rotation and revolution stirring method, and an ultrasonic dispersion method. Next, a thermosetting resin and, if necessary, a curing agent are added to the obtained organic solvent-dispersed carbon nanotubes, and the mixture is stirred at room temperature for a predetermined time by a stirring apparatus, whereby a carbon nanotube-containing composition can be prepared. Examples of the stirring device include a jet mill, a cutter mill, a disk mill, and a ball mill.

Next, a method for producing a thermally cured product of the carbon nanotube-containing composition of the present invention will be described. The method for producing a thermally cured product of a carbon nanotube-containing composition includes, for example, the following steps: a step of applying a carbon nanotube-containing composition onto a film, the carbon nanotube-containing composition comprising (A) carbon nanotubes, (B) an organic solvent, and (C) a thermosetting resin, wherein the absolute value of the difference between the boiling point (T1) of the organic solvent (B) and the thermosetting reaction initiation temperature (T2) of the thermosetting resin (C) is 70 ℃ or less; and (C) volatilizing the organic solvent (B) and initiating a thermosetting reaction of the thermosetting resin (C) by heat-treating the composition containing carbon nanotubes.

(Process of applying to film)

The carbon nanotube-containing composition prepared as described above is applied to a film, whereby a laminated structure of a coating film of the carbon nanotube-containing composition and a film can be obtained. In this case, when the composition containing carbon nanotubes is applied in a sheet form, a sheet-like layered structure can be obtained. The method for applying the carbon nanotube-containing composition is not particularly limited, and known methods such as a comma coater method, a screen printing method, an ink jet method, a roll coater method, a bar coater method, a spray coater method, a curtain coater method, a doctor blade method, an applicator method, a blade coater method, a knife coater method, and a gravure coater method can be used. The thickness of the coating film of the composition containing carbon nanotubes is not particularly limited, and may be, for example, in the range of 5 to 100 μm.

When the film is used as a release film, examples of the material of the film include polyimide, polyester (polyethylene, polypropylene, polyethylene terephthalate, and the like), and the like.

(Heat treatment Process)

By the heat treatment, the organic solvent is volatilized and the thermosetting resin is thermally cured, whereby the coating film of the carbon nanotube-containing composition can be thermally cured. The temperature of the heat treatment may be appropriately selected depending on the heat curing initiation temperature of the thermosetting resin, and for example, in the case of using an epoxy resin or a silicone resin as the thermosetting resin, 70 to 250 ℃ is mentioned, and the time of the heat treatment may be, for example, 1 to 60 minutes.

Subsequently, the film is peeled off from the laminated structure, whereby a thermally cured product (for example, a sheet-like thermally cured product) of the composition containing carbon nanotubes can be obtained.

Examples

Next, examples of the present invention will be described, but the present invention is not limited to these examples as long as the gist thereof is not exceeded.

(example 1)

< preparation of carbon nanotube-containing composition >

9 parts by mass of bisphenol A type epoxy resin (trade name: YD-128, manufactured by Nissan epoxy Co., Ltd., mass average molecular weight: 400, softening point: 25 ℃ C. or lower, liquid, epoxy equivalent: 190) as a thermosetting resin as a binder resin, 1 part by mass of diethylenetriamine (manufactured by MITSUI FINE CHEMICALS, Inc., purity: 99% or higher, specific gravity: 0.95) as an epoxy resin curing agent, and 177 parts by mass of single-walled carbon nanotubes (trade name: ZEONANO (registered trademark) 03 DS-ZeNP-RD, manufactured by Japan on Corporation, solid content: 0.3% by mass, average length: 100 μm or higher, G/D band ratio: 5.0 or higher) dispersed in N-methyl-2-pyrrolidone as an organic solvent were weighed in a 250ml plastic container (trade name: Pack Ace P-250, manufactured by TERAOKA), the resulting mixture was stirred for 10 minutes by a planetary stirring/defoaming device (trade name: MAZERUSTAR KK-250, manufactured by Kogyo Co., Ltd.) to obtain a composition containing carbon nanotubes.

< production of conductive Member >

A coating film was formed by applying 10g of the carbon nanotube-containing composition to a polyimide film by a comma coater method, and then heated at 200 ℃ for 30 minutes to volatilize the organic solvent from the coating film and thermally cure the coating film, thereby forming a thermally cured coating film having a thickness of 10 μm. Thus, a sheet-like conductive member of example 1 was obtained.

(example 2)

The sheet-like conductive member of example 2 was obtained in the same manner as in example 1 except that 265 parts by mass of single-walled carbon nanotubes (trade name: EC1.5P-NMP, manufactured by mitsubishi nano carbon corporation, solid content 0.2% by mass, average length 5 to 10 μm, G/D band ratio 50 or more) dispersed in N-methyl-2-pyrrolidone were used in the preparation of the carbon nanotube-containing composition.

(example 3)

The sheet-like conductive member of example 3 was obtained in the same manner as in example 1 except that 265 parts by mass of single-walled carbon nanotubes (trade name: EC2.0P-NMP, manufactured by mitsubishi nano carbon corporation, solid content 0.2% by mass, average length 10 to 15 μm, G/D band ratio 50 or more) dispersed in N-methyl-2-pyrrolidone was used in the preparation of the carbon nanotube-containing composition.

(example 4)

The sheet-like conductive member of example 4 was obtained in the same manner as in example 1 except that 375 parts by mass of single-walled carbon nanotubes (trade name: EC2.0P-NMP, manufactured by mitsubishi nano carbon corporation, solid content 0.2% by mass, average length 10 to 15 μm, G/D band ratio 50 or more) dispersed in N-methyl-2-pyrrolidone were used in the preparation of the carbon nanotube-containing composition.

(example 5)

A sheet-like conductive member of example 5 was obtained in the same manner as in example 1 except that 555 parts by mass of single-walled carbon nanotubes (trade name: EC2.0P-NMP, manufactured by Nakamura nanocarbon Co., Ltd., average length of 10 to 15 μm, G/D band ratio of 50 or more) dispersed in N-methyl-2-pyrrolidone were used in the preparation of the carbon nanotube-containing composition.

(example 6)

A sheet-like conductive member of example 6 was obtained in the same manner as in example 2 except that 9 parts by mass of a liquid epoxy resin having poor crystallinity (trade name: ZX-1059, manufactured by Nikkiso epoxy Co., Ltd., viscosity 2250 mPas, softening point: 25 ℃ C. or lower, liquid, epoxy equivalent: 165) was used in place of the bisphenol A type epoxy resin in the preparation of the composition containing carbon nanotubes.

(example 7)

A sheet-like conductive member of example 7 was obtained in the same manner as in example 2 except that 9 parts by mass of a cyclic aliphatic diglycidyl ether-based epoxy resin (trade name: ZX-1658GS, manufactured by Nikkiso epoxy Co., Ltd., viscosity: 50 mPas, softening point: 25 ℃ C. or lower, liquid, epoxy equivalent: 133) was used in place of the bisphenol A-type epoxy resin in the preparation of the composition containing carbon nanotubes.

(example 8)

A sheet-like conductive member of example 8 was obtained in the same manner as in example 2 except that 7 parts by mass of polydimethylsiloxane having a silanol group (trade name: XP1434, manufactured by JNC K.K., viscosity 50mPa · S, liquid state) as a silicone resin was used instead of the bisphenol A type epoxy resin, and 3 parts by mass of alkoxyepoxysilane (trade name: S-510, manufactured by JNC K.K., 3-glycidoxypropyltrimethoxysilane) was used instead of diethylenetriamine.

(example 9)

The sheet-like conductive member of example 9 was obtained in the same manner as in example 1 except that 500 parts by mass of single-walled carbon nanotubes (trade name: ZEONANO (registered trademark) 03DS-NP-RD, manufactured by Japan Zeon Corporation, solid content 0.3% by mass, average length 100 μm or more, G/D band ratio 5.0 or more) dispersed in N-methyl-2-pyrrolidone were used as carbon nanotubes in the preparation of the carbon nanotube-containing composition.

(example 10)

A sheet-like conductive member of example 10 was obtained in the same manner as in example 2 except that 7 parts by mass of polydimethylsiloxane having a silanol group (trade name: FM-9915, manufactured by JNC Co., Ltd., viscosity 130 mPas, liquid state) as a silicone resin was used instead of the bisphenol A type epoxy resin and 3 parts by mass of alkoxyepoxysilane (trade name: S-510, manufactured by JNC Co., Ltd., 3-glycidoxypropyltrimethoxysilane) was used instead of diethylenetriamine in the preparation of the carbon nanotube-containing composition.

Comparative example 1

A sheet-like conductive member of comparative example 1 was obtained in the same manner as in example 1 except that 151 parts by mass of single-walled carbon nanotubes (trade name: 03DS-MK-RD, manufactured by Japan Zeon Corporation, solid content 0.35% by mass, average length 100 μm or more, G/D band ratio 5.0) dispersed in methyl ethyl ketone were used in the preparation of the carbon nanotube-containing composition.

Comparative example 2

A sheet-like conductive member of comparative example 2 was obtained in the same manner as in example 1 except that 265 parts by mass of single-walled carbon nanotubes (trade name: EC1.5P-MEK, manufactured by Nacheng nanocarbon Co., Ltd., solid content 0.2% by mass, average length 5 to 10 μm, G/D band ratio 50 or more) dispersed in methyl ethyl ketone were used in the preparation of the carbon nanotube-containing composition.

The conductive members of the examples and comparative examples obtained as described above were subjected to the following measurement and evaluation.

(boiling point of organic solvent (T1))

The organic solvent used for the organic solvent-dispersed carbon nanotubes used in the examples and comparative examples was measured for its boiling point (T1) using a melting point measuring apparatus (model M-560, manufactured by Kaita scientific Co., Ltd.) under a temperature rising rate of 5 ℃ per minute. The results are shown in tables 1 and 2 below.

(Heat curing reaction initiation temperature (T2))

The thermosetting resins and curing agents used in the examples and comparative examples were weighed in amounts shown in tables 1 and 2 in a 250ml plastic container (trade name: Pack Ace P-250, manufactured by TERAOKA corporation), and stirred for 10 minutes by a planetary stirring/defoaming device (trade name: MAZERUSTAR KK-250, manufactured by sanko corporation). For these samples, the temperature was raised from room temperature to 300 ℃ at a temperature raising rate of 5 ℃ per minute by a differential scanning calorimeter (model: DSC7000, manufactured by Hitachi High-Tech Science Corporation) according to the above-mentioned measurement method, and measurement was performed, and the heat curing reaction initiation temperature (T2) was measured from the resulting exothermic peak.

(evaluation of film Property)

When the polyimide films were peeled from the conductive members of the examples and comparative examples, the fracture state of the thermosetting coating film was visually evaluated. The cured coating film was evaluated as "good" when it could be peeled off without breaking, and as "poor" when it broken. The results are shown in tables 1 and 2.

(evaluation of Dispersion of Carbon Nanotube (CNT))

The conductive members obtained in the examples and comparative examples were cut into almost half portions in the thickness direction with a microtome (trade name: EMUC7, manufactured by Leica), and the dispersion state of CNTs was observed by observing the cross-section with a transmission electron microscope (trade name: JEM-ARM300F, manufactured by JEOL Ltd.). All the observation surfaces were evaluated as "o" when CNTs were singly dispersed and as "x" when aggregates of CNTs were observed. The results are shown in tables 1 and 2.

(volume resistivity)

The conductive members obtained in the examples and comparative examples were punched out with a 12.5mm diameter punch to obtain disk-shaped test pieces having a diameter of 12.5mm and a thickness of 10 μm. The volume resistivity of the test piece was measured by a four-terminal method using a high-precision high-function low resistivity meter (model GX, manufactured by Mitsubishi chemical analysis, Ltd., measurement terminal: PSP probe MCP-TP06P RMH 112). The results are shown in tables 1 and 2.

As is clear from Table 1, in examples 1 to 10 in which the absolute value of the difference between the boiling point of the organic solvent (T1) and the thermosetting reaction initiation temperature (T2) of the thermosetting resin is 70 ℃ or lower, aggregation of the carbon nanotubes is prevented and monodispersion is performed. In examples 1 to 10, the volume resistivity can be reduced, and excellent conductivity can be obtained in the entire conductive member. Therefore, it is understood that in examples 1 to 10, even if the wiring of the circuit device to be inspected is narrowed in pitch and the wiring is thinned, the conduction inspection can be performed with good accuracy. In particular, it is known that: in examples 1 to 8 and 10 in which 5 to 10 mass% of carbon nanotubes were contained in 100 mass% of the total solid content of the composition containing carbon nanotubes, film formability was also excellent and the composition could be easily formed into a sheet shape, as compared with example 9 in which 13 mass% of carbon nanotubes were contained in 100 mass% of the total solid content of the composition containing carbon nanotubes.

In examples 1 to 10, since carbon nanotubes were used as the conductive material without mixing a metal component, the electrodes and circuit devices to be inspected could be prevented from being contaminated with the metal material even when used as the conductive member for conduction inspection.

On the other hand, as is clear from table 2 above, in comparative examples 1 to 2 in which the absolute value of the difference between the boiling point (T1) of the organic solvent and the thermosetting reaction initiation temperature (T2) of the thermosetting resin exceeded 70 ℃, aggregation of the carbon nanotubes occurred. In comparative examples 1 to 2, the volume resistivity was increased, and good conductivity as a conductive member could not be obtained.

Industrial applicability

The composition containing carbon nanotubes of the present invention can obtain excellent conductivity over the entire conductive member as a thermally cured product, and therefore can be used as a conductive member for conduction test that does not contain a metal component as a conductive material. Further, since the conductive member which is a thermoset product of the carbon nanotube-containing composition can be molded into a sheet shape, a conductive sheet for conduction test can be formed. The anisotropic conductive sheet can also be formed by filling the through-hole of the insulating sheet provided with a plurality of through-holes penetrating in the thickness direction with the carbon nanotube-containing composition of the present invention and curing the filled composition.

Claims

1. A carbon nanotube-containing composition comprising (A) carbon nanotubes, (B) an organic solvent and (C) a thermosetting resin,

an absolute value of a difference between a boiling point (T1) of the (B) organic solvent and a thermosetting reaction initiation temperature (T2) of the (C) thermosetting resin is 70 ℃ or lower,

the organic solvent has a boiling point (T1) higher than a heat curing reaction initiation temperature (T2) of the thermosetting resin,

the carbon nanotube-containing composition contains the (A) carbon nanotubes in an amount of 0.1 to 10.0 mass% based on 100 mass% of the total solid content.

2. The carbon nanotube-containing composition according to claim 1, wherein the intensity ratio G/D of a G band to a D band of a Raman spectrum obtained by Raman spectroscopy of the (A) carbon nanotube is 1.0 or more, and the average length of the (A) carbon nanotube is 1.0 μm or more.

3. The carbon nanotube-containing composition according to claim 1 or 2, wherein the (C) thermosetting resin is an epoxy resin.

4. The carbon nanotube-containing composition of claim 1 or 2, wherein the carbon nanotubes are single-walled carbon nanotubes.

5. A thermoset product of the carbon nanotube-containing composition according to any one of claims 1 to 4.

6. The thermosetting product according to claim 5, wherein the volume resistivity is 0.1 Ω -cm or less.

7. A method for producing a thermally cured product of a composition containing carbon nanotubes, wherein,

the manufacturing method comprises the following steps:

a step of applying a carbon nanotube-containing composition onto a film, the carbon nanotube-containing composition comprising (A) carbon nanotubes, (B) an organic solvent and (C) a thermosetting resin, the absolute value of the difference between the boiling point (T1) of the organic solvent (B) and the thermosetting reaction initiation temperature (T2) of the thermosetting resin (C) being 70 ℃ or less, the boiling point (T1) of the organic solvent being higher than the thermosetting reaction initiation temperature (T2) of the thermosetting resin; and

a step of volatilizing the organic solvent (B) and initiating a thermosetting reaction of the thermosetting resin (C) by heat-treating the composition containing carbon nanotubes,

8. The production method according to claim 7, wherein the thermally cured product constitutes a conductive sheet having a thickness of 1 μm or more and 500 μm or less.