JP6838462B2 - Compositions for forming conductors, conductors and methods for manufacturing them, laminates and devices - Google Patents

Description

The present invention relates to a composition for forming a conductor, a conductor and a method for producing the conductor, a laminate, and an apparatus.

As a method for forming a metal pattern, a step of forming a layer containing metal on a substrate by inkjet printing, screen printing, or the like of an ink containing metal particles such as copper or a conductive material such as a paste, and a step of heating the conductive material to metal A so-called printed electronics method is known, which includes a step of forming a conductor by sintering particles to develop conductivity. As the metal particles contained in the conductive material, for example, those in which an organic substance as a coating material is adhered to the surface in order to suppress oxidation of the metal and improve storage stability are known (for example, Patent Document 1 and Patent). Reference 2).

Japanese Unexamined Patent Publication No. 2012-0272418 Japanese Unexamined Patent Publication No. 2014-148732

However, depending on the type of the base material, the conductor formed by sintering the metal particles may not have sufficient adhesive strength and may peel off from the base material, resulting in a defect of the device. Materials of base materials used in recent years are diversifying into resins, metals, ceramics, glass, resins containing inorganic fillers, etc. Among them, for base materials containing inorganic materials such as ceramics, glass, resins containing inorganic fillers, etc. Improving the adhesiveness of conductors has become an issue.

Examples of the method for improving the adhesive force of the conductor to the base material include a method of adding a resin component to a conductor-forming composition such as a paste containing metal particles. However, the addition of an insulating resin component tends to inhibit the sintering of metal particles and prevent the development of sufficient conductivity. For this reason, it has been difficult to achieve both adhesiveness to the base material and conductivity of the conductor. Further, when metal particles are sintered at a low temperature (for example, 200 ° C. or lower) to form a conductor, the conductivity may be significantly impaired even if a small amount of resin component is added.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a conductor-forming composition capable of forming a conductor having excellent adhesiveness and conductivity to a base material.

The present invention relates to the conductor-forming compositions shown in the following [1] to [4], the method for producing the conductors shown in the following [5] and [6], the conductor shown in the following [7], and the lamination shown in the following [8]. The body and the device shown in the following [9] are provided.

[1] The content of the resin containing the copper-containing particles, the resin having a urethane bond, and the silane coupling agent and having the urethane bond is 3.0 parts by mass to 100 parts by mass with respect to 100 parts by mass of the copper-containing particles. A composition for forming a conductor, which is 15.0 parts by mass.
[2] The conductor-forming composition according to [1], wherein the content of the silane coupling agent is 0.25 parts by mass to 4.0 parts by mass with respect to 100 parts by mass of the copper-containing particles.
[3] The composition for forming a conductor according to [1] or [2], wherein the resin having a urethane bond has at least one group selected from the group consisting of an alkoxysilyl group and a silanol group.
[4] The composition for forming a conductor according to any one of [1] to [3], wherein the copper-containing particles include core particles containing copper and an organic substance that covers at least a part of the surface of the core particles. ..
[5] A method for producing a conductor, comprising a step of heating the conductor-forming composition according to any one of [1] to [4] to obtain a sintered body.
[6] The method for producing a conductor according to [5], further comprising a step of forming a plating layer on the sintered body.
[7] A conductor comprising a sintered body obtained by sintering the conductor-forming composition according to any one of [1] to [4].
[8] A laminate comprising a base material and the conductor according to [7] provided on the base material.
[9] An apparatus comprising the conductor according to [7].

According to the present invention, there is provided a conductor forming composition capable of forming a conductor having excellent adhesiveness and conductivity to a base material. Further, a conductor using such a conductor-forming composition, a method for producing the conductor, a conductor, a laminate, and an apparatus are provided.

6 is a transmission electron microscope image of the copper-containing particles synthesized in Production Example 1.

Hereinafter, embodiments for carrying out the present invention will be described in detail. However, the present invention is not limited to the following embodiments. In the following embodiments, the components (including element steps and the like) are not essential unless otherwise specified. The same applies to the numerical values and their ranges, and does not limit the present invention.

In the present specification, the term "process" refers to a process that is independent of other processes, and even if the process cannot be clearly distinguished from other processes, if the purpose of the process is achieved, the process is also included. included.

In the present specification, the numerical range indicated by using "~" includes the numerical values before and after "~" as the minimum value and the maximum value, respectively.

In the numerical range described stepwise in the present specification, the upper limit value or the lower limit value described in one numerical range may be replaced with the upper limit value or the lower limit value of another numerical range described stepwise. Good. Further, in the numerical range described in the present specification, the upper limit value or the lower limit value of the numerical range may be replaced with the value shown in the examples.

In the present specification, the content rate or content of each component in the composition is the plurality of types present in the composition unless otherwise specified, when a plurality of substances corresponding to the respective components are present in the composition. Means the total content or content of the substances in.

In the present specification, the particle size of each component in the composition refers to the particle size of each component in the composition when a plurality of particles corresponding to each component are present in the composition, unless otherwise specified. Means the value for the mixture.

In the present specification, the term "layer" or "membrane" refers to a part of the region in addition to the state formed in the entire region when the region in which the layer or the membrane exists is observed. The state formed only in is also included.

In the present specification, "lamination" means stacking layers, and two or more layers may be bonded or two or more layers may be detachable.

As used herein, "conductorization" means fusing metal-containing particles into a conductor. The “conductor” refers to an object having conductivity, and more specifically, an object having a volume resistivity of 2000 mΩ · cm or less. In the present specification, the volume resistivity of the conductor is obtained from the surface resistivity value measured by the four-ended needle surface resistance measuring device and the non-contact surface / layer cross-sectional shape measurement system (trade name: VertScan, Ryoka System Co., Ltd.). It is a value calculated from the thickness of the film. The term "conductor" also includes a conductive object provided with a conductive layer (for example, a plating layer).

In the present specification, the conductor-forming composition is "sintered", that is, the "sintered body" contains copper while a part or all of the resin having a urethane bond and the silane coupling agent remains. This includes either a state in which the particles are completely or partially fused and integrated (fused), or a state in which the copper-containing particles are not fused and are only in contact with each other.

<Conductor forming composition>
The conductor-forming composition of the present embodiment contains copper-containing particles, a resin having a urethane bond, and a silane coupling agent. The content of the resin having a urethane bond is 3.0 parts by mass to 15.0 parts by mass with respect to 100 parts by mass of the copper-containing particles. Specific examples of the conductor forming composition include conductive paints, conductive pastes, and conductive inks.

[Copper-containing particles]
The copper-containing particles contain at least metallic copper and may contain other substances as needed. Examples of other substances include metals such as gold, silver, platinum, tin and nickel, compounds containing these metal elements, organic substances, copper oxide, copper chloride and the like. From the viewpoint of forming a conductor having better conductivity, the content of copper in the copper-containing particles is preferably 50% by mass or more, more preferably 60% by mass or more, and more preferably 70% by mass or more. Is even more preferable.

The size of the copper-containing particles is not particularly limited, but from the viewpoint of sinterability at low temperatures, copper-containing particles having a major axis length of 50 nm or less (hereinafter, may be referred to as “small diameter particles”). The ratio is preferably 55% by number or less.

As used herein, the major axis of the copper-containing particles means the distance between the two planes circumscribing the copper-containing particles and selected so that the distance between the two planes parallel to each other is maximized. In the present specification, the proportion of copper-containing particles having a major axis length of 50 nm or less is the proportion of 200 randomly selected copper-containing particles. For example, when the number of copper-containing particles having a major axis length of 50 nm or less is 110 out of 200, the proportion of copper-containing particles having a major axis length of 50 nm or less is 55% by number.

From the viewpoint of sinterability at low temperature, the proportion of copper-containing particles having a major axis length of 50 nm or less is preferably 50% by number or less, more preferably 35% by number or less, and 20 or less. It is more preferably less than or equal to%.

From the viewpoint of sinterability at low temperature, the proportion of copper-containing particles having a major axis length of 70 nm or more is preferably 30% by number or more, more preferably 50% by number or more, and 60 or more. It is more preferably% or more. As used herein, the proportion of copper-containing particles having a major axis length of 70 nm or more means a proportion of 200 randomly selected copper-containing particles.

From the viewpoint of sinterability at low temperature, the average value of the length of the major axis of the copper-containing particles is preferably 55 nm or more, more preferably 70 nm or more, and further preferably 90 nm or more. As used herein, the mean length of the major axis means the arithmetic mean of the length of the major axis measured for 200 randomly selected copper-containing particles.

From the viewpoint of sinterability at low temperature, the average value of the length of the major axis of the copper-containing particles is preferably 500 nm or less, more preferably 300 nm or less, and further preferably 200 nm or less.

From the viewpoint of sinterability at low temperature, copper-containing particles having the longest major axis length (hereinafter, may be referred to as "maximum diameter particles") have a major axis length of 500 nm or less. Is more preferable, and it is more preferably 300 nm or less, and further preferably 250 nm or less. As used herein, the length of the major axis of the maximum diameter particles means the length of the major axis of the copper-containing particles having the longest major axis length among the 200 randomly selected copper-containing particles. To do.

From the viewpoint of sinterability at low temperature, copper-containing particles having the shortest major axis length (hereinafter, may be referred to as "minimum diameter particles") have a major axis length of 5 nm or more. Is more preferable, and it is more preferably 8 nm or more, and further preferably 10 nm or more. As used herein, the length of the major axis of the smallest diameter particle means the length of the major axis of the copper-containing particle having the shortest major axis length among 200 randomly selected copper-containing particles. To do.

The length of the major axis of the copper-containing particles adjusts the conditions such as the type of raw material in the method for producing copper-containing particles described later, the temperature at which the raw materials are mixed, the reaction time, the reaction temperature, the washing step, and the washing solvent. Can be done by doing.

The average value of the aspect ratio, which is the ratio of the major axis to the minor axis (major axis / minor axis) of the copper-containing particles, is preferably 1.0 to 8.0, and is preferably 1.1 to 6.0. More preferably, it is more preferably 1.2 to 3.0. In the present specification, the mean value of the aspect ratio is obtained by calculating the long-axis arithmetic mean value and the short-axis arithmetic mean value of 200 randomly selected copper-containing particles, respectively, and obtaining the long-axis arithmetic mean value. Is a value obtained by dividing by the arithmetic mean value on the short axis. The minor axis of the copper-containing particles means the distance between the two planes circumscribing the copper-containing particles and selected so that the distance between the two planes parallel to each other is minimized.

The aspect ratio of the copper-containing particles can be adjusted, for example, by adjusting the conditions such as the carbon number of the fatty acid used in the method for producing the copper-containing particles described later.

The lengths of the major axis and the minor axis of the copper-containing particles can be measured by a known method such as observation with an electron microscope. The magnification when observing with an electron microscope is not particularly limited, but can be, for example, 20 times to 50,000 times. When randomly selecting copper-containing particles from the electron microscope image, copper-containing particles having a particle diameter of less than 3 nm are excluded from the measurement target.

From the viewpoint of promoting sintering at a low temperature, the copper-containing particles preferably contain copper-containing particles having irregularities on the surface. More specifically, it is more preferable that the average value of the circularity is 0.70 to 0.99. The circularity is a value represented by 4π × S / L ² , and S and L are the area and the circumference (outer circumference) of the particle to be measured in an electron microscope (two-dimensional image), respectively. .. The circularity can be obtained by analyzing an electron microscope image using image processing software, and the average value of the circularity is the average value of the circularity measured for 200 arbitrarily selected copper-containing particles. ..

It is not clear why the copper-containing particles contain copper-containing particles having irregularities on the surface to promote sintering at low temperature, but the presence of irregularities on the surface of the copper-containing particles causes the melting point due to the so-called nanosize effect. It is presumed that the decrease will occur and the sinterability at low temperature will be promoted.

The shape of the copper-containing particles is not particularly limited, and can be selected from shapes such as spherical, long-granular, flat, and fibrous according to the use of the conductor-forming composition. When the conductor-forming composition is applied to the printing method, the shape of the copper-containing particles is spherical or long-granular (specifically, for example, the average value of the aspect ratio is 1.5 to 8.0). It is preferable because the viscosity of the mixture can be easily adjusted.

From the viewpoint of storage stability, the copper-containing particles preferably include core particles containing copper and an organic substance that covers at least a part of the surface of the core particles. In such copper-containing particles, the organic substance plays a role as a protective material, and the oxidation of the core particles tends to be suppressed. Therefore, good sinterability at low temperature tends to be maintained even after long-term storage in the atmosphere. The organic matter is thermally decomposed or volatilized by heating when the copper-containing particles are sintered, and completely or partially disappears.

The organic substance that covers at least a part of the surface of the core particles preferably contains an organic substance derived from an alkylamine. The fact that the core particles are coated with an organic substance or alkylamine is obtained by heating the copper-containing particles at a temperature higher than the temperature at which the organic substance or alkylamine thermally decomposes or volatilizes in a nitrogen atmosphere, and comparing the masses before and after heating. You can check.

The proportion of the organic matter covering at least a part of the surface of the core particles is preferably 0.1% by mass to 20% by mass with respect to the total of the core particles and the organic matter. When the proportion of organic matter is 0.1% by mass or more, sufficient oxidation resistance tends to be obtained. When the proportion of organic matter is 20% by mass or less, the sinterability at low temperature tends to be good. The ratio of the organic matter to the total of the core particles and the organic matter is more preferably 0.3% by mass to 10% by mass, and further preferably 0.5% by mass to 5% by mass.

The core particles contain at least metallic copper and may optionally contain other materials. Other substances include metals such as gold, silver, platinum, tin, and nickel, compounds containing these metal elements, fatty acid copper, reducing compounds, or organic substances derived from alkylamine, which will be described later, inside the core particles. Examples include organic substances, copper oxide, and copper chloride that have entered. From the viewpoint of forming a conductor having better conductivity, the content of copper in the core particles is preferably 50% by mass or more, more preferably 60% by mass or more, and further preferably 70% by mass or more. preferable.

Since at least a part of the surface of the core particles of the copper-containing particles is covered with an organic substance, the oxidation of copper is suppressed even when stored in the atmosphere, and the oxide content tends to be small. For example, the content of oxides in the copper-containing particles may be 5% by mass or less. The content of oxides in the copper-containing particles can be measured by, for example, XRD (X-ray diffraction, X-ray diffraction).

(Manufacturing method of copper-containing particles)
The method for producing the copper-containing particles is not particularly limited. For example, copper-containing particles are produced by a method comprising a step of heating and stirring a composition containing a metal salt of a fatty acid and copper, a reducing compound, and an alkylamine. The method may include steps such as a centrifugation step and a washing step after the heating and stirring step, if necessary.

The above method uses a metal salt of fatty acid and copper as a copper precursor. It is considered that this makes it possible to use an alkylamine having a lower boiling point (that is, a smaller molecular weight) as a reaction medium as compared with the method described in Patent Document 1 in which silver oxalate or the like is used as a copper precursor. Be done. As a result, in the obtained copper-containing particles, the organic matter existing on the surface of the core particles becomes more easily thermally decomposed or volatilized, and the copper-containing particles are sintered (fused) and changed into a conductor at a low temperature. Will be easier.

(fatty acid)
The fatty acid is a monovalent carboxylic acid represented by RCOOH (R is a chain hydrocarbon group, which may be linear or branched). The fatty acid may be either a saturated fatty acid or an unsaturated fatty acid. Linear saturated fatty acids are preferred from the viewpoint of efficiently coating core particles and suppressing oxidation. One type of fatty acid may be used alone, or two or more types may be used in combination.

The number of carbon atoms of the fatty acid is preferably 9 or less. Examples of saturated fatty acids having 9 or less carbon atoms include acetic acid (2 carbon atoms), propionic acid (3 carbon atoms), butyric acid and isobutyric acid (4 carbon atoms), valeric acid and isovaleric acid (5 carbon atoms), and caproic acid. Examples thereof include acids (6 carbon atoms), enanthic acid and isoenanthic acid (7 carbon atoms), caprylic acid, isocaprylic acid and isocaproic acid (8 carbon atoms), nonanoic acid and isononanoic acid (9 carbon atoms). Examples of unsaturated fatty acids having 9 or less carbon atoms include those having one or more double bonds in the hydrocarbon groups of the above-mentioned saturated fatty acids.

The type of fatty acid can affect properties such as dispersibility of copper-containing particles in a dispersion medium and fusion property. Therefore, it is preferable to select the type of fatty acid according to the use of the copper-containing particles. From the viewpoint of homogenizing the particle shape, it is preferable to use a fatty acid having 5 to 9 carbon atoms and a fatty acid having 4 or less carbon atoms in combination. For example, it is preferable to use nonanoic acid having 9 carbon atoms and acetic acid having 2 carbon atoms in combination. The ratio when the fatty acid having 5 to 9 carbon atoms and the fatty acid having 4 or less carbon atoms are used in combination is not particularly limited.

The method for obtaining a salt compound of fatty acid and copper (fatty acid copper) is not particularly limited. For example, it may be obtained by mixing copper hydroxide and a fatty acid in a solvent, or commercially available fatty acid copper may be used. Alternatively, by mixing copper hydroxide, a fatty acid and a reducing compound in a solvent, the formation of the fatty acid copper and the formation of the complex formed between the fatty acid copper and the reducing compound are carried out in the same step. May be good.

(Reducing compound)
It is considered that the reducing compound forms a complex compound such as a complex between the two compounds when mixed with the fatty acid copper. As a result, the reducing compound becomes a donor of electrons to the copper ions in the fatty acid copper, and the reduction of the copper ions is likely to occur, and the copper atoms are liberated by spontaneous thermal decomposition as compared with the fatty acid copper in the uncomplexed state. Is likely to occur. One type of reducing compound may be used alone, or two or more types may be used in combination.

Specific examples of the reducing compound include hydrazine, hydrazine derivative, hydrazine hydrochloride, hydrazine sulfate, hydrazine sulfate such as hydrazine hydrate, hydroxylamine compound such as hydroxylamine and hydroxylamine derivative, sodium boron hydride, sodium sulfite, and hydrogen sulfite. Examples thereof include sodium compounds such as sodium, sodium thiosulfate, and sodium hypophosphate.

The reducing compound preferably has an amino group from the viewpoints of easily forming a coordination bond with respect to the copper atom in the fatty acid copper and easily forming a complex while maintaining the structure of the fatty acid copper. Examples of the reducing compound having an amino group include hydrazine and its derivative, hydroxylamine and its derivative, and the like.

From the viewpoint of lowering the heating temperature in the step of heating the composition containing the fatty acid copper, the reducing compound and the alkylamine (for example, 150 ° C. or lower), the reducing compound is in a temperature range in which the alkylamine does not evaporate or decompose. , It is preferable to select a compound that easily reduces copper ions and easily releases from copper atoms. Examples of such reducing compounds include hydrazine and its derivatives, hydroxylamine and its derivatives, and the like. Since these reducing compounds have a nitrogen atom, the nitrogen atom can form a coordinate bond with a copper atom to form a complex. In addition, since these reducing compounds generally have stronger reducing power than alkylamines, the formed complex undergoes spontaneous decomposition under relatively mild conditions, resulting in reduction of copper ions and liberation from copper atoms. It tends to be easy.

By selecting a suitable derivative from these derivatives instead of hydrazine or hydroxylamine, the reactivity with the fatty acid copper can be adjusted, and a complex that causes spontaneous decomposition can be produced under desired conditions. Examples of hydrazine derivatives include methyl hydrazine, ethyl hydrazine, n-propyl hydrazine, isopropyl hydrazine, n-butyl hydrazine, isobutyl hydrazine, sec-butyl hydrazine, t-butyl hydrazine, n-pentyl hydrazine, isopentyl hydrazine, and neo-pentyl hydrazine. , T-pentyl hydrazine, n-hexyl hydrazine, isohexyl hydrazine, n-heptyl hydrazine, n-octyl hydrazine, n-nonyl hydrazine, n-decyl hydrazine, n-undecyl hydrazine, n-dodecyl hydrazine, cyclohexyl hydrazine, phenyl Examples thereof include hydrazine, 4-methylphenylhydrazine, benzylhydrazine, 2-phenylethylhydrazine, 2-hydrazinoethanol, acetohydrazine and the like. Examples of the hydroxylamine derivative include N, N-di (sulfoethyl) hydroxylamine, monomethylhydroxylamine, dimethylhydroxylamine, monoethylhydroxylamine, diethylhydroxylamine, N, N-di (carboxyethyl) hydroxylamine and the like. Can be done.

The ratio of copper contained in the fatty acid copper to the reducing compound is not particularly limited as long as the desired complex is formed. For example, the ratio (copper: reducing compound) can be in the range of 1: 1 to 1: 4 on a molar basis, preferably in the range of 1: 1 to 1: 3, and 1: 1 to 1. : It is more preferable to set it in the range of 2.

(Alkylamine)
The alkylamine is considered to function as a reaction medium for the decomposition reaction of the complex formed from the fatty acid copper and the reducing compound. Furthermore, it is considered that the protons generated by the reducing action of the reducing compound are captured, and the reaction solution is inclined to be acidic to suppress the oxidation of copper atoms.

Alkylamines are primary amines represented by RNH ₂ (R is a hydrocarbon group and may be cyclic or branched), R ₁ R ₂ NH (R ₁ and R ₂ are the same. It may be a hydrocarbon group which may be different, and may be a secondary amine represented by cyclic or branched), an alkylenediamine in which two amino groups are substituted in a hydrocarbon chain, or the like. .. Alkylamines may have one or more double bonds and may have atoms such as oxygen, silicon, nitrogen, sulfur and phosphorus. One type of alkylamine may be used alone, or two or more types may be used in combination.

The hydrocarbon group of the alkylamine preferably has 7 or less carbon atoms. When the hydrocarbon group of the alkylamine has 7 or less carbon atoms, the alkylamine is easily thermally decomposed during heating for fusing the copper-containing particles to form a conductor, and the copper-containing particles are satisfactorily burned. It tends to be able to bind (fuse). More preferably, the hydrocarbon group of the alkylamine has 6 or less carbon atoms. The lower limit of the number of carbon atoms of the hydrocarbon group of the alkylamine may be, for example, 3 or more.

Specifically, as primary amines, ethylamine, 2-ethoxyethylamine, propylamine, butylamine, isobutylamine, pentylamine, isopentylamine, hexylamine, cyclohexylamine, heptylamine, octylamine, nonylamine, decylamine, dodecylamine, Hexadecylamine, oleylamine, 3-methoxypropylamine, 3-ethoxypropylamine and the like can be mentioned.

Specific examples of the secondary amine include diethylamine, dipropylamine, dibutylamine, ethylpropylamine, ethylpentylamine, dibutylamine, dipentylamine, dihexylamine and the like.

Specifically, as alkylenediamine, ethylenediamine, N, N-dimethylethylenediamine, N, N'-dimethylethylenediamine, N, N-diethylethylenediamine, N, N'-diethylethylenediamine, 1,3-propanediamine, 2,2 -Dimethyl-1,3-propanediamine, N, N-dimethyl-1,3-diaminopropane, N, N'-dimethyl-1,3-diaminopropane, N, N-diethyl-1,3-diaminopropane, 1,4-diaminobutane, 1,5-diamino-2-methylpentane, 1,6-diaminohexane, N, N'-dimethyl-1,6-diaminohexane, 1,7-diaminoheptane, 1, Examples thereof include 8-diaminooctane, 1,9-diaminononane, and 1,12-diaminododecane.

The alkylamine preferably contains at least one of the alkylamines having 7 or less carbon atoms in the hydrocarbon group. Thereby, copper-containing particles having excellent sinterability (fusing property) at low temperature can be produced. One type of alkylamine may be used alone, or two or more types may be used in combination. The alkylamine may include an alkylamine having a hydrocarbon group having 7 or less carbon atoms and an alkylamine having a hydrocarbon group having 8 or more carbon atoms. When an alkylamine having 7 or less carbon atoms in a hydrocarbon group and an alkylamine having 8 or more carbon atoms in a hydrocarbon group are used in combination, the alkylamine having 7 or less carbon atoms in the hydrocarbon group as a whole. Is preferably 50% by mass or more, more preferably 60% by mass or more, and further preferably 70% by mass or more.

The ratio of copper to alkylamine contained in the fatty acid copper is not particularly limited as long as the desired copper-containing particles can be obtained. For example, the ratio (copper: alkylamine) can be in the range of 1: 1 to 1: 8 on a molar basis, preferably in the range of 1: 1 to 1: 6, and 1: 1 to 1: 1. The range of 4 is more preferable.

The method for carrying out the step of heating and stirring the composition containing the fatty acid copper, the reducing compound and the alkylamine is not particularly limited. For example, a method in which fatty acid copper and a reducing compound are mixed in a solvent and then an alkylamine is added and heated, a method in which fatty acid copper and an alkylamine are mixed in a solvent and then a reducing compound is added and heated, a method in which fatty acid copper is added and heated. A method of mixing and heating copper hydroxide and fatty acid, reducing compounds and alkylamine, which are the starting materials of fatty acid copper, in a solvent, and reducing after mixing copper hydroxide and fatty acid, which are starting materials of fatty acid copper, in a solvent. Examples thereof include a method of adding a sex compound and heating.

The heating and stirring step can be performed at a relatively low temperature by using fatty acid copper having 9 or less carbon atoms as the copper precursor. For example, it can be carried out at 150 ° C. or lower, preferably at 130 ° C. or lower, and more preferably at 100 ° C. or lower.

The composition containing the fatty acid copper, the reducing compound and the alkylamine may further contain a solvent. It is preferable to contain a polar solvent from the viewpoint of promoting the formation of a complex of the fatty acid copper and the reducing compound. Here, the polar solvent means a solvent that dissolves in water at 25 ° C. The use of polar solvents tends to promote the formation of complexes. The reason is not clear, but it is considered that the contact with the water-soluble reducing compound is promoted while dissolving the solid fatty acid copper. One type of solvent may be used alone, or two or more types may be used in combination.

Examples of the polar solvent include alcohols that dissolve in water at 25 ° C. Examples of the alcohol that dissolves in water at 25 ° C. include alcohols having 1 to 8 carbon atoms and having one or more hydroxyl groups in the molecule. Examples of such alcohols include linear alkyl alcohols, phenols, and those in which the hydrogen atom of a hydrocarbon having an ether bond in the molecule is replaced with a hydroxyl group. From the viewpoint of expressing stronger polarity, an alcohol containing two or more hydroxyl groups in the molecule is also preferably used. Further, alcohol containing a sulfur atom, a phosphorus atom, a silicon atom and the like may be used depending on the use of the produced copper-containing particles.

Specific examples of alcohols include methanol, ethanol, 1-propanol, 2-propanol, butanol, pentanol, hexanol, heptanol, octanol, allyl alcohol, benzyl alcohol, pinacol, propylene glycol, menthol, catechol, hydroquinone, salicyl alcohol, Examples thereof include glycerin, pentaerythritol, sucrose, glucose, xylitol, methoxyethanol, triethylene glycol monomethyl ether, ethylene glycol, triethylene glycol, tetraethylene glycol and pentaethylene glycol.

Of the alcohols, methanol, ethanol, 1-propanol and 2-propanol, which have extremely high solubility in water, are preferable, 1-propanol and 2-propanol are more preferable, and 1-propanol is further preferable.

[Resin with urethane bond]
The molecular structure and molecular weight of the resin having a urethane bond are not particularly limited, and can be selected according to the use of the conductor-forming composition, the type of the base material, and the like. The resin having a urethane bond may be thermoplastic or thermosetting. As the resin having a urethane bond, one type may be used alone, or two or more types having different molecular structures, molecular weights, etc. may be used in combination.

From the viewpoint of adhesiveness to a substrate containing an inorganic material such as ceramic, glass, or an inorganic filler-containing resin, the resin having a urethane bond further has at least one group selected from the group consisting of an alkoxysilyl group and a silanol group. Is preferable. The silicon atom contained in such a group has a high affinity with an inorganic material, and there is a tendency that a sufficient adhesive strength improving effect can be obtained even in a small amount. Further, having such a group improves the heat resistance of the conductor-forming composition, and tends to suppress deterioration of the conductor-forming composition due to the heating step for sintering the copper-containing particles.

Specific examples of the alkoxysilyl group include a methoxysilyl group, a dimethoxysilyl group, a trimethoxysilyl group, an ethoxysilyl group, a diethoxysilyl group, a triethoxysilyl group, a proproxysilyl group, a butoxysilyl group, and an isoproproxysilyl group. Can be mentioned. When the resin having a urethane bond has an alkoxysilyl group, the alkoxysilyl group may be only one type or two or more different types.

Whether or not the conductor-forming composition contains a resin having a urethane bond can be confirmed by, for example, infrared absorption spectrum measurement. Specifically, when a resin having a urethane bond (-NH-COO-) is contained, ^{a peak near 3300 cm -1 derived from NH stretching vibration, a peak near 1720 cm -1} derived from CO stretching vibration, and the like can be observed.

Whether or not the composition for forming a conductor contains a urethane bond and a resin having at least one group selected from the group consisting of an alkoxysilyl group and a silanol group is determined, for example, by ICP emission spectroscopy, ²⁹ Si-NMR measurement, red. It can be confirmed by external absorption spectroscopy.

The content of the resin having a urethane bond is 3.0 parts by mass to 15.0 parts by mass and preferably 5.0 parts by mass to 15.0 parts by mass with respect to 100 parts by mass of the copper-containing particles. It is more preferably 6.0 parts by mass to 12.0 parts by mass. When the content of the resin having a urethane bond is 3.0 parts by mass or more with respect to 100 parts by mass of the copper-containing particles, the adhesive force of the conductor to the substrate tends to be sufficiently obtained. When the content of the resin having a urethane bond is 15.0 parts by mass or less with respect to 100 parts by mass of the copper-containing particles, the increase in the volume resistivity of the conductor tends to be suppressed.

[Silane coupling agent]
The type of the silane coupling agent is not particularly limited, and can be selected according to the type of the target base material, the operating temperature, and the like. One type of silane coupling agent may be used alone, or two or more types may be used in combination. Further, the silane coupling agent may be soluble or insoluble in the dispersion medium in the conductor-forming composition.

Examples of the silane coupling agent include methyltrimethoxysilane, methyltriethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltriacetoxysilane, and vinyl-tris (2-). Methoxyethoxy) silane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, methyltri (methacryloxyethoxy) silane, 3-acryloxypropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3- Aminopropyltriethoxysilane, N-2- (aminoethyl) -3-aminopropyltrimethoxysilane, N-2- (aminoethyl) -3-aminopropylmethyldimethoxysilane, N-2- (N-vinylbenzylamino) Ethyl) -3-aminopropyltrimethoxysilane, 3-anilinopropyltrimethoxysilane, 3-ureidopropyltrimethoxysilane, 3-ureidopropyltriethoxysilane, 3- (4,5-dihydroimidazolyl) propyltriethoxysilane , 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropylmethyldiisopropenoxysilane, Methyltriglycidoxysilane, 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 3-mercaptopropylmethyldimethoxysilane, trimethylsilylisocyanate, dimethylsilylisocyanate, phenylsilyltriisocyanate, tetraisocyanatesilane, methylsilyltriisocyanate , Vinylsilyl triisocyanate, ethoxysilane triisocyanate and the like.

Among these silane coupling agents, a silane coupling agent having a great effect of improving the bond or wettability of the interface between the materials in the conductor forming composition is preferable.

The content of the silane coupling agent is preferably 0.25 parts by mass to 4.0 parts by mass, and preferably 0.5 parts by mass to 3.0 parts by mass with respect to 100 parts by mass of the copper-containing particles. More preferred. When the amount of the coupling agent is 0.25 parts by mass or more with respect to 100 parts by mass of the copper-containing particles, the effect of improving the adhesive strength tends to be more easily obtained. Further, when the amount of the coupling agent is 4.0 parts by mass or less with respect to 100 parts by mass of the copper-containing particles, the conductor-forming composition is less likely to gel, and the film-forming property of the conductor-forming composition is better. become.

It is not clear why a conductor containing a sintered body obtained by sintering a conductor-forming composition containing copper-containing particles, a resin having a urethane bond, and a silane coupling agent has excellent adhesiveness to a base material. For example, since the resin having a urethane bond has a relatively high polarity, it is considered that a sufficient effect of improving the adhesiveness to the substrate can be exhibited even with a small amount of addition. Further, since the silane coupling agent has a high affinity for both the copper particles which are inorganic substances and the urethane-based resin, it is considered that the adhesiveness to the base material is improved.

It is not clear why a conductor containing a sintered body obtained by sintering a conductor-forming composition containing copper-containing particles, a resin having a urethane bond, and a silane coupling agent has excellent conductivity, but for example, in general. Thermosetting resins with a high curing rate, such as epoxy resin and acrylic resin, which are added to improve adhesive strength, are faster than sintering copper-containing particles in the heating process for sintering copper-containing particles. While thermosetting of the resin tends to proceed and sufficient sintering is hindered, the resin having a urethane bond is thermoplastic (does not cure) or has a relatively high curing rate even if it is thermosetting. It is considered that because it is slow, it is difficult to prevent the sintering of copper-containing particles and good conductivity is easily exhibited. Further, it is considered that the resin having a urethane bond tends to exhibit good conductivity because the volume shrinkage contracts when the resin is cured and the contact of the copper particles progresses. Further, when the resin containing the urethane bond shrinks, the silane coupling agent exhibits curing similar to that of the cross-linking agent, so that the volume shrinkage of the resin containing the urethane bond further progresses, and the resin containing the urethane bond is used alone. It is considered that good conductivity is more likely to be developed than in the case.

[Dispersion medium]
The conductor-forming composition may contain a dispersion medium. The type of the dispersion medium is not particularly limited, and can be selected from commonly used organic solvents depending on the use of the conductor-forming composition, and one type may be used alone or two or more types may be used in combination. When the conductor-forming composition is applied to a printing method, at least one selected from the group consisting of terpineol, isobornylcyclohexanol, dihydroterpineol and dihydroterpineol acetate from the viewpoint of viscosity control of the conductor-forming composition. Is preferably included.

The viscosity of the conductor-forming composition is not particularly limited and can be selected according to the method of using the conductor-forming composition. For example, when the conductor-forming composition is applied to a screen printing method, the viscosity is preferably 0.1 Pa · s to 30 Pa · s, and more preferably 1 Pa · s to 30 Pa · s. When the composition for forming a conductor is applied to an inkjet printing method, the viscosity is preferably 0.1 mPa · s to 30 mPa · s, and 5 mPa · s to 20 mPa · s, although it depends on the standard of the inkjet head used. Is more preferable. The viscosity of the conductor forming composition is measured at 25 ° C. using an E-type viscometer (manufactured by Toki Sangyo Co., Ltd., product name: VISCOMETER-TV22, applicable cone plate type rotor: 3 ° × R17.65). Means.

[Other ingredients]
The conductor-forming composition may contain copper-containing particles, a resin having a urethane bond, a silane coupling agent, and other components other than the dispersion medium, if necessary. Examples of such a component include resins other than resins having a urethane bond, radical initiators, reducing agents and the like.

When the conductor-forming composition contains a resin other than the resin having a urethane bond, the resin may contain a resin having at least one group selected from the group consisting of an alkoxysilyl group and a silanol group. In this case as well, the same effect as when the conductor-forming composition contains a resin having a urethane bond and at least one group selected from the group consisting of an alkoxysilyl group and a silanol group can be obtained.

When the conductor-forming composition contains a resin other than the resin having a urethane bond, the proportion of the resin having the urethane resin bond in the entire resin is preferably 30% by mass or more from the viewpoint of conductivity and storage stability, and is 50%. It is more preferably 70% by mass or more, and further preferably 70% by mass or more.

Since the conductor forming composition of the present embodiment can be obtained by heating at a low temperature (for example, 200 ° C. or lower), it is preferably used when the conductor is arranged on a base material made of a material having relatively low heat resistance. be able to. Examples of materials having relatively low heat resistance include thermoplastic resins. Examples of the thermoplastic resin include polyolefin resins such as polyethylene, polypropylene and polymethylpentene, and polycarbonate resins. Further, even if the base material has high heat resistance, it can be suitably used even when there is a member having low heat resistance provided in the base material and heating cannot be performed at a high temperature.

<Conductor and its manufacturing method>
The conductor of the present embodiment includes a sintered body obtained by sintering the conductor-forming composition of the above-described embodiment. The shape of the conductor is not particularly limited, and examples thereof include a thin film shape and a pattern shape. The conductor of this embodiment can be used for forming wirings, coatings, etc. of various electronic components. In particular, since the conductor of this embodiment can be manufactured at a low temperature (for example, 200 ° C. or lower), it is suitably used for forming a metal foil, a wiring pattern, or the like on a base material having low heat resistance such as resin. Further, it is suitably used for applications such as decoration and printing that are not intended to be energized.

When a layer made of a conductor-forming composition is formed on a base material and heated to obtain a sintered body, the material of the base material is not particularly limited, and it may or may not have conductivity. Good. Specifically, metals such as Cu, Au, Pt, Pd, Ag, Zn, Ni, Co, Fe, Al and Sn, alloys of these metals, semiconductors such as ITO, ZnO, SnO and Si, glass and ceramics. Examples thereof include carbon materials such as graphite and graphite, resins, papers, and combinations thereof.

The conductor of the present embodiment exhibits excellent adhesiveness to a base material containing an organic material such as resin, and also has excellent adhesion to a base material containing an inorganic material such as ceramic, glass, and an inorganic filler-containing resin. Show sex. The shape of the base material is not particularly limited, and may be a plate shape, a rod shape, a roll shape, a film shape, or the like.

The volume resistivity of the conductor is preferably 2000 mΩ · cm or less, more preferably 200 mΩ · cm or less, further preferably 10 mΩ · cm or less, and particularly preferably 1 mΩ · cm or less.

The adhesive force of the conductor to the substrate is preferably 0.05 N / m or more, more preferably 0.5 N / m or more, further preferably 5.0 N / m or more, and 50.0 N / m. It is particularly preferable that it is m or more. In the present specification, the adhesive force of a conductor to a base material is the adhesion between the base material and the conductor when a conductor having a width of 10 mm is peeled off from the base material at a peel angle of 90 ° and a peel speed of 30 mm / sec using a desktop peel tester. It is a force (N / m).

The conductor of this embodiment can be used for various purposes. Specifically, it is used as a member such as an electric wiring, a heat radiating film, and a surface coating film used for electronic parts such as a laminated board, a solar cell panel, a display, a touch panel, a transistor, a semiconductor package, and a laminated ceramic capacitor. Can be done. In particular, since the conductor of the present embodiment can be formed on a base material such as resin, it is suitable for manufacturing flexible laminated plates, solar cell panels, displays and the like.

The sintered body obtained by heating the conductor-forming composition can also be suitably used as a plating seed layer. When the sintered body is used as the plating seed layer, the type of metal used for the plating layer formed on the plating seed layer is not particularly limited, and the plating method may be either electrolytic plating or electroless plating. Further, the conductor obtained by forming the plating layer on the sintered body can also be used for the above-mentioned various uses.

The method for producing a conductor of the present embodiment includes a step (heating step) of heating the conductor-forming composition of the present embodiment to obtain a sintered body. In the heating step, the organic matter on the surface of the copper-containing particles contained in the conductor-forming composition is completely or partially thermally decomposed or volatilized, and the copper-containing particles are sintered to obtain a sintered body. The conductor-forming composition of the present embodiment can be transformed into a conductor by sintering copper-containing particles at a temperature of 200 ° C. or lower, preferably 180 ° C. or lower. At this time, a part or all of the resin having a urethane bond and the silane coupling agent may remain in the sintered body.

The components in the atmosphere in which the heating step is carried out are not particularly limited, and can be selected from nitrogen, argon and the like used in a normal conductor manufacturing step. Further, a reducing substance such as hydrogen or formic acid may be heated in an atmosphere saturated with nitrogen or the like. The pressure during heating is not particularly limited, but the reduced pressure tends to promote the sintering of copper-containing particles at a lower temperature to change them into conductors.

The heating step may be performed at a constant temperature or while changing the temperature. When the heating step is performed while raising the temperature, it may be performed at a constant temperature rise rate or while changing the temperature rise rate.

The time of the heating step is not particularly limited, and can be selected in consideration of the heating temperature, the heating atmosphere, the amount of copper-containing particles, and the like. The heating method is not particularly limited, and examples thereof include heating with a hot plate, heating with an infrared heater, and heating with a pulse laser.

The method for manufacturing the conductor may include other steps, if necessary. Other steps include a step of providing a layer containing the conductor-forming composition on the substrate before the heating step, a step of removing at least a part of volatile components in the conductor-forming composition by drying or the like before the heating step, and a step of removing at least a part of the volatile components in the conductor-forming composition. Examples include a step of reducing copper oxide produced by heating in a reducing atmosphere after the heating step, a step of performing photocalculation after the heating step to remove residual components, and a step of applying a load to the conductor obtained after the heating step. be able to.

The conductor manufacturing method of the present embodiment may further include a step of forming a plating layer (plating layer forming step) on the sintered body.

In the plating layer forming step, the method of forming the plating layer is not particularly limited, and either electrolytic plating or electroless plating may be used. The type of metal used to form the plating layer is not particularly limited, and examples thereof include copper, nickel, gold, and chromium.

<Laminated body>
The laminate of the present embodiment includes a base material and the conductor of the above-described embodiment arranged on the base material. The type of the base material is not particularly limited, and the base material on which the conductor can be formed may be selected from the above-mentioned ones. The conductor arranged on the base material may be arranged on the entire surface of the base material or may be arranged only on a part of the base material.

<Device>
The apparatus of this embodiment includes the conductor of the above-described embodiment. The type of device is not particularly limited. For example, a wiring made of a conductor of the above-described embodiment, a solar cell panel having a coating film, a display, a touch panel, an electronic component (transistor, ceramic capacitor, semiconductor package, etc.) and the like can be mentioned. In addition, electronic devices, home appliances, industrial machines, transportation machines, etc. incorporating these devices are also included in the devices of the present embodiment.

Hereinafter, the present invention will be specifically described based on examples, but the present invention is not limited thereto.

[Manufacturing Example 1]
[1.1] Synthesis of copper nonanoate To 91.5 g (0.94 mol) of copper (II) hydroxide (Kanto Chemical Co., Inc., special grade), 150 mL of 1-propanol (Kanto Chemical Co., Inc., special grade) was added and stirred. , 370.9 g (2.34 mol) of nonanoic acid (Kanto Chemical Co., Inc.) was added thereto. The resulting mixture was heated and stirred in a separable flask at 90 ° C. for 30 minutes. The obtained solution was filtered while being heated to remove undissolved substances. After that, the mixture was allowed to cool, and the produced copper nonanoate was suction-filtered and washed with hexane until the washing liquid became transparent. The obtained powder was dried in an explosion-proof oven at 50 ° C. for 3 hours to obtain copper (II) nonanoate. The yield was 340 g (yield 96% by mass).

[1.2] Synthesis of Copper-Containing Particles 15.01 g (0.040 mol) of copper (II) nonanoate and 7.21 g (0) of copper (II) acetate anhydride (Kanto Chemical Co., Inc., special grade) obtained above. .040 mol) was placed in a separable flask, 22 mL of 1-propanol and 32.1 g (0.32 mol) of hexylamine (Tokyo Kasei Kogyo Co., Ltd.) were added, and the mixture was dissolved by heating and stirring at 80 ° C. in an oil bath. .. After transferring to an ice bath and cooling to an internal temperature of 5 ° C., 7.72 mL (0.16 mol) of hydrazine monohydrate (Kanto Chemical Co., Inc., special grade) was added, and the mixture was further stirred in the ice bath. The molar ratio of copper: hexylamine is 1: 4. Then, it was heated and stirred at 90 ° C. for 10 minutes in an oil bath. At that time, the reduction reaction accompanied by foaming proceeded, the inner wall of the separable flask exhibited a copper luster, and the solution turned dark red. Centrifugation was performed at 9000 rpm (rotation / min) for 1 minute to obtain a solid. The step of further washing the solid material with 15 mL of hexane was repeated three times to remove the acid residue to obtain a copper cake A containing a powder of copper-containing particles having a copper luster.

When the copper-containing particles contained in the copper cake A synthesized above were observed with a transmission electron microscope (trade name: JEM-2100F, Nippon Denshi Co., Ltd.), the long axis of 200 randomly selected copper-containing particles was observed. The average value of the length is 104 nm, the proportion of copper-containing particles having a major axis length of 50 nm or less is 18% by number, and the proportion of copper-containing particles having a major axis length of 70 nm or more is 67. The number% was, the length of the major axis of the maximum diameter particles was 200 nm, and the average value of the aspect ratio was 1.2. Further, copper-containing particles having irregularities on the surface were observed, and the average value of circularity was 0.81. FIG. 1 shows a transmission electron microscope image of copper-containing particles.

[Examples 1-1 to 1-6 and Comparative Examples 1-1 to 1-5]
Copper cake A (50 parts by mass), terpineol (25 parts by mass), and isobornylcyclohexanol (trade name: Telsolv MTPH, Nippon Terpen Chemical Co., Ltd.) (25 parts by mass) were mixed. Urethane resin A (trade name: U201, Arakawa Chemical Industry Co., Ltd.) having a urethane bond and a methoxysilyl group as an alkoxysilyl group was added to the obtained paste-like mixture as a non-volatile component with respect to 100 parts by mass of copper cake A. The mixture was mixed in the amount (parts by mass) shown in Table 1. Subsequently, a silane coupling agent (trade name: KBM-903, Shin-Etsu Chemical Co., Ltd.) is mixed with 100 parts by mass of copper cake A in an amount (parts by mass) shown in Table 1 to prepare a conductor-forming composition. did.

[Examples 2-1 to 2-6 and Comparative Examples 2-1 to 2-5]
Instead of urethane resin A, urethane resin B (trade name: KL424, Arakawa Chemical Industry Co., Ltd.) having a urethane bond and having neither an alkoxysilyl group nor a silanol group is non-volatile with respect to 100 parts by mass of copper cake A. A composition for forming a conductor was prepared in the same manner as in Example 1-1 and the like except that the amount (part by mass) shown in Table 1 was used as the minute.

[Comparative Examples 3-1 and 3-2]
Liquid epoxy resin (9.95 parts by mass) (trade name: YL980, Mitsubishi Chemical Co., Ltd.), terpineol (45 parts by mass), and isobornylcyclohexanol (trade name: Telsolv MTPH, Nippon Terpen Chemical Co., Ltd.) (45) (Mass by mass) and an imidazole-based epoxy curing agent (trade name: Curesol 2P 4 MHz, Shikoku Kasei Kogyo Co., Ltd.) (0.05 parts by mass) were mixed to prepare an epoxy resin solution.

In the same manner as in Example 1-1 and the like, the above epoxy resin solution was used in place of the urethane resin A in an amount (parts by mass) shown in Table 1 as a non-volatile content with respect to 100 parts by mass of the copper cake A. , A composition for forming a conductor was prepared.

[Comparative Examples 4-1 and 4-2]
A conductor-forming composition was prepared in the same manner as in Example 1-1 and the like except that the urethane resin A was not used.

(Evaluation of gelation)
Whether or not the conductor-forming compositions obtained in Examples and Comparative Examples were gelled was visually observed. Those that were not gelled were evaluated as "○", and those that were gelled were evaluated as "x". The results are shown in Table 1.

(Formation of conductor)
The conductor-forming compositions obtained in Examples and Comparative Examples were applied onto a glass plate as a base material and heated to obtain a thin film (sintered body) containing copper. The heating was carried out by heating to 180 ° C. at a heating rate of 4 ° C./sec and holding for 60 minutes in a nitrogen atmosphere at 1 atm with an oxygen concentration of 100 ppm or less. When a thin film (sintered body) containing copper was observed with a transmission electron microscope (trade name: JEM-2100F, JEOL Ltd.), copper in the conductor forming composition was observed in both Examples and Comparative Examples. The contained particles were sintered together, suggesting the formation of a conductor.

(Evaluation of conductivity)
Next, the volume resistivity of the thin film (sintered body) containing copper was measured with a four-end needle surface resistance measuring device, and the non-contact surface / layer cross-sectional shape measurement system (trade name: VertScan, Ryo Co., Ltd.) It was calculated from the film thickness obtained from the chemical system). The results are shown in Table 1.

[Evaluation of adhesiveness]
A cross-cut test was carried out on the obtained thin film (sintered body) containing copper according to JIS K5400 (width 1 mm). When the adhesive tape was attached to the thin film and the tape was peeled off, the film did not peel off from the glass plate (the number of remaining squares was 100 out of 100), the adhesiveness was "good: ○". It was evaluated as. On the other hand, when the film was peeled off from the glass plate when the tape was peeled off (the number of remaining squares was 99 or less out of 100), the adhesiveness was evaluated as "defective: x". .. The results are shown in Table 1.

As shown in Table 1, formed by using the conductor-forming composition of the example containing 3.0 parts by mass to 15.0 parts by mass of urethane resin A or urethane resin B with respect to 100 parts by mass of copper-containing particles. The thin film (sintered body) containing copper had a low volume resistivity and good conductivity, and also had good adhesiveness to a base material. Further, a thin film (sintered body) containing copper formed by using a urethane resin A having at least one group selected from the group consisting of an alkoxysilyl group and a silanol group and a silane coupling agent has such a group. Compared with the thin film (sintered body) containing copper formed by using the urethane resin B and the silane coupling agent which does not have it, it was superior in adhesiveness and conductivity to the base material. This is because the alkoxysilyl group of the urethane resin A and the alkoxysilyl group of the silane coupling agent have high affinity with the base material (glass), sufficient adhesiveness is exhibited even in a small amount, and contact between copper-containing particles also occurs. It is thought that this is because it became easier.

By using the silane coupling agent, the conductivity of the thin film (sintered body) containing copper was better than when the urethane resin A or the urethane resin B was used alone. It is considered that this is because the silane coupling agent forms a crosslinked structure with the urethane resin during sintering, so that the volume of the conductor-forming composition shrinks and the copper-containing particles easily come into contact with each other. Be done.

The copper-containing thin film (sintered body) formed by using the conductor-forming compositions of Comparative Examples 3-1 and 3-2 using an epoxy resin as a resin component had a high volume resistivity. In Comparative Example 4-1 which did not contain a resin component and used only a coupling agent, the thin film (sintered body) containing copper did not show conductivity. Further, in Comparative Example 4-2 containing no resin component, although the volume resistivity was low, there was almost no adhesive force to the base material.

From these results, it was confirmed that the conductor-forming composition of the present invention can form a conductor having excellent adhesiveness and conductivity to a substrate.

Claims (8)

It contains copper-containing particles, a resin having a urethane bond, and a silane coupling agent.
The resin having a urethane bond has at least one group selected from the group consisting of an alkoxysilyl group and a silanol group.
A conductor-forming composition in which the content of the resin having a urethane bond is 3.0 parts by mass to 15.0 parts by mass with respect to 100 parts by mass of the copper-containing particles. The conductor-forming composition according to claim 1, wherein the content of the silane coupling agent is 0.25 parts by mass to 4.0 parts by mass with respect to 100 parts by mass of the copper-containing particles. The conductor-forming composition according to claim 1 or 2 , wherein the copper-containing particles include core particles containing copper and an organic substance that covers at least a part of the surface of the core particles. A method for producing a conductor, comprising a step of heating the conductor-forming composition according to any one of claims 1 to 3 to obtain a sintered body. The method for manufacturing a conductor according to claim 4 , further comprising a step of forming a plating layer on the sintered body. A conductor comprising a sintered body obtained by sintering the conductor-forming composition according to any one of claims 1 to 3. A laminate comprising a base material and the conductor according to claim 6 provided on the base material. An apparatus comprising the conductor according to claim 6.