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 having 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;
• R1 is a hydrogen atom or a methyl group;
• R2 is a hydrogen atom, a hydrocarbon 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 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 or a monovalent group represented by —CHO, —CH2CHO, —CO—CH═CH2, —O—C(CH3)—CH2 or —CH2COOR14;
• R14 is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms;
• R8, R9, R10, R11, R12 and R13 are each independently a hydrogen atom, a hydrocarbon group or a group in which hydrocarbon groups 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 have a substituent group R15, and R15 is a hydrogen atom, a hydrocarbon group or a group in which hydrocarbon groups are bound by at least one of an ether bond and an ester bond;
• the hydrocarbon group can have a substituent 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;
• R3 is a hydrogen atom or a methyl group;
• “Polymer” is a polymer chain having 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, 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 or a monovalent group represented by —CHO, —CH2CHO or —CH2COOR24;
• R22 is a hydrocarbon 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 having 1 to 18 carbon atoms;
• R24 is an alkyl group having 1 to 5 carbon atoms;
• the hydrocarbon group can have a substituent 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 having 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;
• R1 is a hydrogen atom or a methyl group;
• R2 is a hydrogen atom, a hydrocarbon 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 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 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 having 1 to 5 carbon atoms;
• R8, R9, R10, R11, R12 and R13 are each independently a hydrogen atom, a hydrocarbon group or a group in which hydrocarbon groups 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 have a substituent group R15, and R15 is a hydrogen atom, a hydrocarbon group or a group in which hydrocarbon groups are bound by at least one of an ether bond and an ester bond;
• the hydrocarbon group can have a substituent 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;
• R3 is a hydrogen atom or a methyl group;
• “Polymer” is a polymer chain having 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, 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 or a monovalent group represented by —CHO, —CH2CHO or —CH2COOR24;
• R22 is a hydrocarbon 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 having 1 to 18 carbon atoms;
• R24 is an alkyl group having 1 to 5 carbon atoms;
• the hydrocarbon group can have a substituent 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.