Dispersant, metal particle dispersion for electroconductive substrates, and method for producing electroconductive substrate

A metal particle dispersion for electroconductive substrates, comprising metal particles, a dispersant and an organic solvent,

• wherein the dispersant is a graft copolymer comprising a constitutional unit represented by the following general formula (I) and a constitutional unit represented by the following general formula (II):
• wherein “A” is a direct bond or a divalent linking group, and the divalent linking group as “A” is at least one selected from the group consisting of a linear, branched or cyclic alkylene group, a linear, branched or cyclic alkylene group comprising a hydroxyl group, an arylene group, a —CONH— group, a —COO— group, a —NHCOO— group, an ether group (—O— group), a thioether group (—S— group) and combinations thereof;
• R1 is a hydrogen atom or a methyl group;
• R2 is a hydrogen atom, a hydrocarbon group optionally comprising a substituent group, or a monovalent group represented by —[CH(R4)—CH(R5)—O]s—R6, —[(CH2)t—O]u—R6 or —O—R7;
• R7 is a hydrocarbon group optionally comprising a substituent group, or a monovalent group represented by —[CH(R4)—CH(R5)—O]s—R6, —[(CH2)t—O]u—R6, —C(R8)(R9)—C(R10)(R11)—OH or —CH2—C(R12)(R13)—CH2—OH;
• R4 and R5 are each independently a hydrogen atom or a methyl group;
• R6 is a hydrogen atom, a hydrocarbon group optionally comprising a substituent group, or a monovalent group represented by —CHO, —CH2CHO, —CO—CH═CH2, —CO—C(CH3)═CH2 or —CH2COOR14;
• R14 is a hydrogen atom or an alkyl group comprising 1 to 5 carbon atoms;
• R8, R9, R10, R11, R12 and R13 are each independently a hydrogen atom, a hydrocarbon group optionally comprising a substituent group, or a group in which hydrocarbon groups optionally comprising a substituent group, are bound by at least one of an ether bond and an ester bond, and R8 and R10 can be bound to each other to form a cyclic structure;
• when the cyclic structure is formed, the cyclic structure can comprise a substituent group R15, and R15 is a hydrogen atom, a hydrocarbon group optionally comprising a substituent group, or a group in which hydrocarbon groups optionally comprising a substituent group, are bound by at least one of an ether bond and an ester bond;
• the substituent group in R2, R6, R7, R8, R9, R10, R11, R12, R13 and R15 is at least one selected from the group consisting of a nitro group and a halogen atom, and when R2, R6, R7, R8, R9, R10, R11, R12, R13 and R15 are each a group comprising an aromatic ring, the aromatic ring can comprise a substituent group of an alkyl or alkenyl group;
• s is an integer of 1 to 18;
• t is an integer of 1 to 5;
• and u is an integer of 1 to 18;
• wherein “L” is a direct bond or a divalent linking group, and the divalent linking group as “L” is at least one selected from the group consisting of a linear, branched or cyclic alkylene group, a linear, branched or cyclic alkylene group comprising a hydroxyl group, an arylene group, a —CONH— group, a —COO— group, a —NHCOO— group, an ether group (—O— group), a thioether group (—S— group) and combinations thereof;
• R3 is a hydrogen atom or a methyl group;
• “Polymer” is a polymer chain comprising at least one constitutional unit represented by the following general formula (III) or (IV):
• wherein R17 is a hydrogen atom or a methyl group;
• R18 is a hydrocarbon group optionally comprising a substituent group, a cyano group or a monovalent group represented by —[(CH(R19)—CH(R20)—O]x—R21, —[(CH2)y—O]z—R21, —[CO—(CH2)y—O]z—R21, —CO—O—R22 or —O—CO—R23;
• R19 and R20 are each independently a hydrogen atom or a methyl group;
• R21 is a hydrogen atom, a hydrocarbon group optionally comprising a substituent group, or a monovalent group represented by —CHO, —CH2CHO or —CH2COOR24;
• R22 is a hydrocarbon group optionally comprising a substituent group, a cyano group or a monovalent group represented by —[CH(R19)—CH(R20)—O]x—R21, —[(CH2)y—O]z—R21 or —[CO—(CH2)y—O]z—R21;
• R23 is an alkyl group comprising 1 to 18 carbon atoms and optionally comprising a substituent group;
• R24 is a hydrogen atom or an alkyl group comprising 1 to 5 carbon atoms;
• the substituent group in R18, R21, R22 and R23 is at least one selected from the group consisting of a nitro group, a halogen atom, an alkoxy group, a hydroxyl group, a carboxyl group, an amino group, an epoxy group and an isocyanate group, and when R18, R21, R22 and R23 are each a group comprising an aromatic ring, the aromatic ring can comprise a substituent group of an alkyl or alkenyl group;
• m is an integer of 1 to 5;
• n and n′ are each an integer of 5 to 200;
• x is an integer of 1 to 18;
• y is an integer of 1 to 5;
• and z is an integer of 1 to 18.

A method for producing an electroconductive substrate, comprising the steps of:

• forming a coating film by applying, onto a base material, a coating solution which contains a metal particle dispersion for electroconductive substrates, comprising metal particles, a dispersant and an organic solvent, wherein the dispersant is a graft copolymer comprising a constitutional unit represented by the following general formula (I) and a constitutional unit represented by the following general formula (II), and
• baking the coating film:
• wherein “A” is a direct bond or a divalent linking group, and the divalent linking group as “A” is at least one selected from the group consisting of a linear, branched or cyclic alkylene group, a linear, branched or cyclic alkylene group comprising a hydroxyl group, an arylene group, a —CONH— group, a —COO— group, a —NHCOO— group, an ether group (—O— group), a thioether group (—S— group) and combinations thereof;
• R1 is a hydrogen atom or a methyl group;
• R2 is a hydrogen atom, a hydrocarbon group optionally comprising a substituent group, or a monovalent group represented by —[CH(R4)—CH(R6)—O]s—R6, —[(CH2)t—O]u—R6 or —O—R7;
• R7 is a hydrocarbon group optionally comprising a substituent group, or a monovalent group represented by —[CH(R4)—CH(R5)—O]s—R6, —[(CH2)t—O]u—R6, —C(R8)(R9)—C(R10)(R11)—OH or —CH2—C(R12)(R13)—CH2—OH;
• R4 and R5 are each independently a hydrogen atom or a methyl group;
• R6 is a hydrogen atom, a hydrocarbon group optionally comprising a substituent group, or a monovalent group represented by —CHO, —CH2CHO, —CO—CH═CH2, —CO—C(CH3)═CH2 or —CH2COOR14;
• R14 is a hydrogen atom or an alkyl group comprising 1 to 5 carbon atoms;
• R8, R9, R10, R11, R12 and R13 are each independently a hydrogen atom, a hydrocarbon group optionally comprising a substituent group, or a group in which hydrocarbon groups optionally comprising a substituent group, are bound by at least one of an ether bond and an ester bond, and R8 and R10 can be bound to each other to form a cyclic structure;
• when the cyclic structure is formed, the cyclic structure can comprise a substituent group R15, and R15 is a hydrogen atom, a hydrocarbon group optionally comprising a substituent group, or a group in which hydrocarbon groups optionally comprising a substituent group, are bound by at least one of an ether bond and an ester bond;
• the substituent group in R2, R6, R7, R8, R9, R10, R11, R12, R13 and R15 is at least one selected from the group consisting of a nitro group and a halogen atom, and when R2, R6, R7, R8, R9, R10, R11, R12, R13 and R15 are each a group comprising an aromatic ring, the aromatic ring can comprise a substituent group of an alkyl or alkenyl group;
• s is an integer of 1 to 18;
• t is an integer of 1 to 5;
• and u is an integer of 1 to 18;
• wherein “L” is a direct bond or a divalent linking group, and the divalent linking group as “L” is at least one selected from the group consisting of a linear, branched or cyclic alkylene group, a linear, branched or cyclic alkylene group comprising a hydroxyl group, an arylene group, a —CONH— group, a —COO— group, a —NHCOO— group, an ether group (—O— group), a thioether group (—S— group) and combinations thereof;
• R3 is a hydrogen atom or a methyl group;
• “Polymer” is a polymer chain comprising at least one constitutional unit represented by the following general formula (III) or (IV):
• wherein R17 is a hydrogen atom or a methyl group;
• R18 is a hydrocarbon group optionally comprising a substituent group, a cyano group or a monovalent group represented by —[CH(R19)—CH(R20)—O]x—R21, —[(CH2)y—O]z—R21, —[CO—(CH2)y—O]z—R21, —CO—O—R22 or —O—CO—R23;
• R19 and R20 are each independently a hydrogen atom or a methyl group;
• R21 is a hydrogen atom, a hydrocarbon group optionally comprising a substituent group, or a monovalent group represented by —CHO, —CH2CHO or —CH2COOR24;
• R22 is a hydrocarbon group optionally comprising a substituent group, a cyano group or a monovalent group represented by —[CH(R19)—CH(R20)—O]x—R21, —[(CH2)y—O]z—R21 or —[CO—(CH2)y—O]x—R21;
• R23 is an alkyl group comprising 1 to 18 carbon atoms and optionally comprising a substituent group;
• R24 is a hydrogen atom or an alkyl group comprising 1 to 5 carbon atoms;
• the substituent group in R18, R21, R22 and R23 is at least one selected from the group consisting of a nitro group, a halogen atom, an alkoxy group, a hydroxyl group, a carboxyl group, an amino group, an epoxy group and an isocyanate group, and when R18, R21, R22 and R23 are each a group comprising an aromatic ring, the aromatic ring can comprise a substituent group of an alkyl or alkenyl group;
• m is an integer of 1 to 5;
• n and n′ are each an integer of 5 to 200;
• x is an integer of 1 to 18;
• y is an integer of 1 to 5;
• and z is an integer of 1 to 18.