JPWO2017029884A1 - Conductive composition - Google Patents

Abstract

Provided are a conductive composition that is excellent in durability and conductivity and is low in cost, and a conductive paste including the conductive composition. The conductive composition of the present invention contains flaky metal powder, a salicylic acid compound, and o-aminophenol, and the content of the salicylic acid compound is 0 with respect to 100 parts by weight of the flaky metal powder. 0.04 to 1.6 parts by weight, and the content of the o-aminophenol is 1.2 to 4.5 parts by weight with respect to 100 parts by weight of the flaky metal powder.

Description

  The present invention relates to a conductive composition.

  Conventionally, a method of treating a metal powder with a fatty acid in a conductive paste made of a resin and a metal powder is known. For example, Patent Document 1 discloses a method of enhancing the durability of the flaky copper powder by coating the surface of the flaky copper powder with a fatty acid as an antioxidant. However, when the surface of the copper powder is coated with an antioxidant, there is a problem that the contact resistance value between the copper powders increases, and the performance as a conductive paste cannot be exhibited sufficiently. On the other hand, if the amount of coating with the antioxidant is reduced, there is a problem that sufficient durability cannot be obtained.

  Moreover, in order to improve durability of copper powder itself, the method of coat | covering copper powder with silver is also known. However, this method has a problem of high cost.

JP-A-11-264001

  The present invention has been made in order to solve the above-described conventional problems, and an object of the present invention is to provide a conductive composition that is excellent in durability and conductivity and is low in cost, and the conductive composition. It is in providing the conductive paste containing.

The conductive composition of the present invention contains flaky metal powder, a salicylic acid compound, and o-aminophenol, and the content of the salicylic acid compound is 0 with respect to 100 parts by weight of the flaky metal powder. 0.04 to 1.6 parts by weight, and the content of the o-aminophenol is 1.2 to 4.5 parts by weight with respect to 100 parts by weight of the flaky metal powder.
In one embodiment, flaky copper powder is included as the flaky metal powder.
In one embodiment, salicylic acid is included as the salicylic acid compound.
According to another aspect of the present invention, a conductive paste is provided. The conductive paste includes the conductive composition and a binder resin.

  ADVANTAGE OF THE INVENTION According to this invention, it is excellent in durability and electroconductivity, and can provide the electrically conductive paste containing the electrically conductive composition and this electrically conductive composition of low cost.

A. Conductive Composition The conductive composition of the present invention contains flaky metal powder, a salicylic acid compound, and o-aminophenol.

  In the conductive composition of the present invention, the flaky metal powder is coated with a salicylic acid compound and added with o-aminophenol, so that conductivity and durability (acid resistance, heat resistance, moisture resistance) are increased. Excellent). In particular, the superiority of moisture resistance is remarkable, and the conductive composition maintains the conductivity of the flaky metal powder even under high humidity.

A-1. Flake-like metal powder The flaky metal powder is flaky. By using the flaky metal powder, contact between the metal powders is promoted, and a conductive composition having excellent conductivity can be obtained. In the present specification, the flake shape means a shape close to a flat plate or a thin rectangular parallelepiped, and specifically means a shape having an aspect ratio (major axis length L / thickness t) of 3 or more. The upper limit of the aspect ratio is 300, for example. The major axis length L and the thickness t of the flaky metal powder can be measured by observing an SEM photograph with a scanning electron microscope (SEM).

  The average particle diameter of the flaky metal powder is preferably 3 μm to 25 μm, more preferably 5 μm to 20 μm, and further preferably 7 μm to 20 μm. If it is such a range, the electroconductive composition which is more excellent by electroconductivity and durability can be obtained. The average particle size means the particle size (primary particle size) at an integrated value of 50% in the particle size distribution obtained by the laser diffraction scattering method.

  As a metal which comprises the said flaky metal powder, copper, silver, gold | metal | money, nickel etc. are mentioned, for example. Moreover, you may use the flaky metal powder obtained from the metal particle (for example, silver covering copper particle) of the multilayer structure comprised from 2 or more types of metals. Preferably, flaky copper powder is used from the viewpoint of conductivity and cost.

  The flaky copper powder can be obtained, for example, by processing copper particles obtained by any appropriate method into a flaky shape by any appropriate method. Examples of the method for producing copper particles before processing include an atomizing method, a wet reduction method, and an electrolysis method. Preferably, the copper particles are electrolytic copper particles obtained by an electrolysis method. If electrolytic copper particles are used, a conductive composition having higher conductivity can be obtained. The copper particles can be processed using, for example, a media mill such as a rolling ball mill, an attritor, or an SC mill. By processing using a media mill, collision and shearing forces act on the particles between the inner wall of the device and the media, and between the media, and the particles are repeatedly expanded, crushed and agglomerated. The particles are processed into flakes.

  In one embodiment, the processing of the copper particles (flaking the copper particles) is performed after mixing the copper particles and the predetermined amount of the salicylic acid compound, or after mixing the copper particles and the predetermined amount of the salicylic acid compound. It is performed with mixing (ie, while processing and mixing are performed simultaneously). If it does in this way, the electroconductive composition which is excellent in electroconductivity and durability can be obtained.

A-2. Salicylic acid compound In the conductive composition of the present invention, the content of the salicylic acid compound is 0.04 to 1.6 parts by weight, preferably 0, with respect to 100 parts by weight of the flaky metal powder. 0.07 to 1.3 parts by weight, more preferably 0.1 to 1 part by weight, and still more preferably 0.3 to 0.8 parts by weight.

  Examples of the salicylic acid compounds include salicylic acid, salicylamide, salicylhydroxamic acid, salicylaldoxime, salicylhydrazide, N, N′-bissalicyloylhydrazine, and poly (N, N′-bissalicyloylhydrazine) alkanes. And salicylic acid derivatives. Of these, salicylic acid is preferable.

  In the present invention, by mixing the flaky metal powder and a specific amount of the salicylic acid compound, the flaky metal powder and the salicylic acid compound form a chelate structure, and the flaky metal powder is coated well. The As a result, a conductive composition excellent in conductivity and durability can be obtained. Moreover, such an effect becomes more remarkable by using flaky copper powder as the flaky metal powder and using salicylic acid as the salicylic acid compound.

A-3. o-Aminophenol In the conductive composition of the present invention, the content of the o-aminophenol is 1.2 to 4.5 parts by weight, preferably 100 parts by weight of the flaky metal powder. Is 1.2 to 4 parts by weight, more preferably 1.2 to 3 parts by weight.

  Since the conductive composition of the present invention is added with a specific amount of o-aminophenol, the flaky metal powder is prevented from being oxidized and is excellent in durability (particularly moisture resistance). The conductive composition of the present invention maintains its conductivity even when left for a long time under high humidity (for example, 90% RH).

  In one embodiment, the conductive composition is produced by adding the o-aminophenol after flaking the copper particles as described in the section A-1. In another embodiment, the conductive composition is formed by processing the copper particles (ie, flaking the copper particles), while the copper particles, the predetermined amount of salicylic acid, and the predetermined amount of o-amino. Manufactured by mixing with phenol. By simultaneously flaking the copper particles and mixing the components, a conductive composition having excellent conductivity and excellent durability can be obtained.

B. Conductive paste The conductive paste of the present invention contains a conductive composition and a binder resin. As the conductive composition, the conductive composition described in the above section A is used.

  Any appropriate resin can be used as the binder resin.

  In one embodiment, a thermoplastic resin is used as the binder resin. Examples of the thermoplastic resin include polyethylene, polypropylene, polyester, polyacrylate, polymethacrylate, polyamide, and the like. These resins may be used alone or in combination of two or more.

  In one embodiment, a thermosetting resin is used as the binder resin. Examples of thermosetting resins include epoxy resins, phenolic resins, diallyl phthalate resins, unsaturated alkyd resins, urethane resins, bismaleidotriazine resins, silicone resins, acrylic resins, melamine resins, A urea-based resin or the like is used. These resins may be used alone or in combination of two or more. Among these, an epoxy resin or a phenol resin is preferable. As the epoxy resin, an epoxy resin having an aromatic ring such as a benzene ring, a biphenyl ring or a naphthalene ring is preferably used, and a phenoxy resin is more preferably used. Examples of the phenoxy resin include a bisphenol A type phenoxy resin obtained using bisphenol A as a bisphenol compound, a bisphenol F type phenoxy resin obtained using bisphenol F, and the like. Preferably, bisphenol A type phenoxy resin is used.

  As the phenoxy resin, those having a large molecular weight (degree of polymerization) are preferably used. The weight average molecular weight of the phenoxy resin is, for example, 10,000 or more, preferably 30000 or more, more preferably 35000 or more, and further preferably 35,000 to 600,000. If a high molecular weight phenoxy resin is used, a conductive paste having excellent heat resistance can be obtained. High molecular weight epoxy resins tend to be hardened (low curing temperature, short curing time) and are advantageous. The weight average molecular weight can be measured by GPC (solvent: THF).

  The content of the binder resin is preferably 8 parts by weight to 25 parts by weight, more preferably 10 parts by weight to 12 parts by weight with respect to 100 parts by weight of the flaky metal powder in the conductive composition.

  The conductive paste of the present invention may further contain a coupling agent. By adding the coupling agent, it is possible to prevent the flaky metal powder from being oxidized. As the coupling agent, for example, a silane coupling agent or a titanium coupling agent can be used, and a titanium coupling agent is preferably used. Examples of the silane coupling agent include vinyltrichlorosilane, vinyltrimethoxysilane, vinyltriethoxysilane, 2- (3,4 epoxycyclohexyl) ethyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3- Glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-methacrylic Roxypropyltriethoxysilane, 3-acryloxypropyltrimethoxysilane, N-2 (aminoethyl) 3-aminopropylmethyldimethoxysilane, N-2 (aminoethyl) 3-aminopropyltrimethoxy Lan, N-2 (aminoethyl) 3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-mercaptopropylmethyldimethoxysilane, 3-mercaptopropyltrimethoxysilane, bis (Triethoxysilylpropyl) tetrasulfide and the like. Examples of the titanium-based coupling agent include isopropyl tristearoyl titanate, isopropyl tris (dioctyl pyrophosphate) titanate, isopropyl tri (N-aminoethylaminoethyl) titanate, tetraoctyl bis (ditridecyl phosphate) titanate, tetra ( 2-2 monodiallyloxymethyl-11-butyl) bis (ditridecyl) phosphate titanate, bis (dioctylpyrophosphate) oxyacetate titanate, bis (dioctylpyrophosphate) ethylene titanate and the like.

  The conductive paste of the present invention may further contain a solvent. In one embodiment, a solvent that can dissolve the binder resin can be selected. By adding such a solvent, the fluidity of the conductive paste can be controlled. Specific examples of the solvent include organic solvents such as butyl carbitol, ethyl carbitol, and γ-butyrolactone. A solvent may be used individually by 1 type and may be used in combination of 2 or more types.

  The conductive paste of the present invention may further contain any appropriate other additive. Examples of other additives include antifoaming agents, antioxidants, viscosity modifiers, diluents, anti-settling materials, leveling agents, and coupling agents.

  In one embodiment, the conductive paste further includes an antifoaming agent. Examples of the antifoaming agent include a silicon antifoaming agent and an acrylic antifoaming agent. The addition amount of the antifoaming agent is not limited, but the minimum amount necessary for defoaming during screen printing is preferable.

  The conductive paste of the present invention can be produced by any appropriate method. For example, a phenoxy resin can be dissolved in a solvent to prepare a varnish, and the conductive composition can be added to the varnish and stirred. As a stirring method, a method using a self-revolving mixer, a triple roll, a kneader or the like can be employed.

  Typically, the conductive paste of the present invention can be used by coating on a transparent conductive film. For example, a conductive paste is applied on a transparent conductive layer (for example, ITO layer) formed on a transparent conductive film by any appropriate method, and then heated and cured. Examples of the coating method include screen printing, flexure printing, gravure printing, and the like; spraying, brushing, bar coating, and the like. Preferably, a screen printing method is used.

  EXAMPLES Hereinafter, although an Example demonstrates this invention concretely, this invention is not limited by these Examples. In Examples, unless otherwise specified, “parts” and “%” are based on weight.

[Example 1]
300 g of copper particles (trade name “ECY” manufactured by Mitsui Mining & Smelting Co., Ltd.) and 0.9 g of salicylic acid were placed in a ball mill (capacity: 300 mL, 5 mmφ alumina balls about 300 g) and mixed for 5 hours. By the said operation, the mixture of the flaky copper powder obtained by repeating expansion | extension, grinding | pulverization, and aggregation of a copper particle and salicylic acid was obtained. To the obtained mixture, 7.5 g of o-aminophenol was further added to obtain a conductive composition.

[Example 2]
A conductive composition was obtained in the same manner as in Example 1 except that the amount of salicylic acid was 0.15 g.

[Example 3]
A conductive composition was obtained in the same manner as in Example 1 except that the amount of salicylic acid was 0.3 g.

[Example 4]
A conductive composition was obtained in the same manner as in Example 1 except that the amount of salicylic acid was 1.5 g.

[Example 5]
A conductive composition was obtained in the same manner as in Example 1 except that the amount of salicylic acid was 2.1 g.

[Example 6]
A conductive composition was obtained in the same manner as in Example 1 except that the amount of salicylic acid was 3 g.

[Example 7]
A conductive composition was obtained in the same manner as in Example 1 except that the amount of salicylic acid was 4.5 g.

[Example 8]
A conductive composition was obtained in the same manner as in Example 1 except that the blending amount of o-aminophenol was 4.5 g.

[Example 9]
A conductive composition was obtained in the same manner as in Example 1 except that the blending amount of o-aminophenol was 10.5 g.

[Example 10]
A conductive composition was obtained in the same manner as in Example 1 except that the blending amount of o-aminophenol was 13.5 g.

[Comparative Example 1]
A conductive composition was obtained in the same manner as in Example 1 except that salicylic acid was not blended.

[Comparative Example 2]
A conductive composition was obtained in the same manner as in Example 1 except that the amount of salicylic acid was 0.06 g.

[Comparative Example 3]
A conductive composition was obtained in the same manner as in Example 1 except that the amount of salicylic acid was 5.1 g.

[Comparative Example 4]
300 g of copper particles (trade name “ECY”, manufactured by Mitsui Mining & Smelting Co., Ltd.) and 0.9 g of o-aminophenol were placed in a ball mill (capacity: 300 mL, 5 mmφ alumina balls) and mixed for 5 hours. . By this operation, a mixture of flaky copper powder obtained by repeating the spreading, pulverization, and aggregation of copper particles and salicylic acid was obtained. To the obtained mixture, 7.5 g of o-aminophenol was further added to obtain a conductive composition.

[Comparative Example 5]
A conductive composition was obtained in the same manner as in Example 1 except that 0.9 g of oxalic acid was used instead of 0.9 g of salicylic acid.

[Comparative Example 6]
A conductive composition was obtained in the same manner as in Example 1 except that 0.9 g of oleic acid was used instead of 0.9 g of salicylic acid.

[Comparative Example 7]
A conductive composition was obtained in the same manner as in Example 1 except that 0.9 g of triethanolamine was used instead of 0.9 g of salicylic acid.

[Comparative Example 8]
A conductive composition was obtained in the same manner as in Example 1 except that the amount of o-aminophenol was 0.3 g.

[Comparative Example 9]
A conductive composition was obtained in the same manner as in Example 1 except that the amount of o-aminophenol was 3 g.

[Comparative Example 10]
A conductive composition was obtained in the same manner as in Example 1 except that the blending amount of o-aminophenol was 15 g.

[Comparative Example 11]
300 g of spherical copper particles (trade name “MA-C05K” manufactured by Mitsui Mining & Smelting Co., Ltd.), 0.9 g of salicylic acid, and 7.5 g of o-aminophenol were mixed to obtain a conductive composition.

<Evaluation>
A conductive paste was prepared from the conductive compositions obtained in Examples and Comparative Examples, and the conductive paste was subjected to the following evaluation. The results are shown in Table 1.

(1) Volume resistivity (initial)
Epoxy resin (trade name “JER1256”, bisphenol A type phenoxy resin, manufactured by Mitsubishi Chemical Corporation) and butyl carbitol were mixed to prepare a varnish. The conductive composition obtained above was added to this varnish to obtain a conductive paste. In addition, the epoxy resin (solid content) in the conductive paste was blended so as to be 10 parts by weight with respect to 100 parts by weight of the flaky copper powder (copper particles in Comparative Example 10).
A conductive paste was printed in a line between two copper electrodes formed on a PET substrate, and then heated at 120 ° C. for 10 minutes using an air oven to obtain a measurement sample.
Printing employed screen printing, and a 180 mesh polyester screen was used. The line was 10 mm wide and 60 mm long.
The resistance value between the electrodes was measured by a four-terminal method. The volume resistivity was obtained from the obtained resistance value by the following formula.
Volume resistivity σ = W × D × R / L
σ: Volume resistivity (Ω · cm)
W: Coating width (cm)
D: Coating thickness (cm)
L: Coating film length (cm)
R: Measurement resistance value (Ω)
(2) Volume resistivity (after moisture resistance test)
The conductive compositions obtained in Examples and Comparative Examples were left for 168 hours in an environment of 40 ° C./90% RH. A conductive paste was prepared and the volume resistivity of the conductive paste was measured in the same manner as in the evaluation (1) except that the conductive composition after being placed under high humidity was used. .

As is apparent from Table 1, when the conductive composition of the present invention is used, a conductive paste having excellent durability and conductivity can be obtained.

Claims (4)

Containing flaky metal powder, a salicylic acid compound, and o-aminophenol,
The content of the salicylic acid compound is 0.04 to 1.6 parts by weight with respect to 100 parts by weight of the flaky metal powder,
The content ratio of the o-aminophenol is 1.2 parts by weight to 4.5 parts by weight with respect to 100 parts by weight of the flaky metal powder.
Conductive composition.   The electrically conductive composition of Claim 1 containing flaky copper powder as said flaky metal powder.   The conductive composition according to claim 1, comprising salicylic acid as the salicylic acid-based compound. A conductive paste comprising the conductive composition according to claim 1 and a binder resin.