Conductive composition for molded film, molded film, molded article, and method for production thereof
Provided is a conductive composition for molded film that enables production of a molded film for which tensile force-induced reductions in conductivity are suppressed. The conductive composition for molded film contains a resin (A), conductive fine particles (B), and a solvent (C), wherein the solvent (C) contains, in 100 parts by mass of the solvent (C), at least 40 parts by mass of a solvent (C′) that satisfies the following condition (1) and condition (2). (1) A boiling point of 180° C. to 270° C. (2) At least one of the following is satisfied: the polar parameter δp of the Hansen solubility parameter (HSP) is 0≤δp≤5.0, and the hydrogen-bond parameter δh of the Hansen solubility parameter (HSP) is 9.8≤δh≤4.0.
1. A conductive composition for molded film, comprising: a resin (A), conductive fine particles (B), a solvent (C), and a crosslinking agent (D),
wherein a weight average molecular weight of the resin (A) is 20,000 or more and 600,000 or less,
a content ratio of the resin (A) is 8% by mass or more and 40% by mass or less, based on a total solid content contained in the conductive composition,
wherein the resin (A) comprises two or more of one or more types of reactive functional groups selected from a hydroxy group, an amino group, a carboxyl group, and an acid anhydride group in a molecule,
wherein a shape of the conductive fine particles (B) is flake shape,
wherein the solvent (C) comprises, in 100 parts by mass of the solvent (C), 40 parts by mass or more of a solvent (C′) is at least one selected from the group consisting of diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, diethylene glycol dibutyl ether, triethylene glycol monomethyl ether, triethylene glycol dimethyl ether, benzyl alcohol, tetralin, terpineol, triacetin, propylene glycol, 1,3-butylene glycol, 1,4-butylene glycol, dipropylene glycol monopropyl ether, diethylene glycol monopropyl ether, dipropylene glycol monomethyl ether, tripropylene and glycol monomethyl ether,
wherein the crosslinking agent (D) has two or more reactive functional groups capable of forming a crosslink with the reactive functional group of the resin (A) in one molecule,
wherein a ratio between a total amount F D (mol) of a substance amount of a second reactive functional group of the crosslinking agent (D) and a mass M A (g) of the resin (A) satisfies the following formula (1):
5.0×10 −5 ≤F D /M A ≤6.0×10 −4 . formula (1)
2. The conductive composition for molded film according to claim 1 , wherein the conductive fine particles (B) comprise one or more types of conductive fine particles selected from silver powder, copper powder, silver-coated powder, copper alloy powder, conductive oxide powder, and carbon fine particles.
3. A molded film, comprising a conductive layer on a base film, wherein the conductive layer is a cured product of the conductive composition for molded film according to claim 1 .
4. The molded film according to claim 3 , wherein a relationship between breaking elongation rates of respective layers at a softening point temperature of the base film satisfies:
breaking elongation rate of the base film>breaking elongation rate of the conductive layer.
5. The molded film according to claim 3 , wherein the base film is a film selected from polycarbonate, polymethylmethacrylate, and polyethylene terephthalate, or a laminated film of polycarbonate, polymethylmethacrylate, and polyethylene terephthalate.
6. A molded film, comprising a decorative layer and a conductive layer on a base film, wherein the conductive layer is a cured product of the conductive composition for molded film according to claim 1 .
7. The molded film according to claim 6 , wherein a relationship between breaking elongation rates of respective layers at a softening point temperature of the base film satisfies:
breaking elongation rate of the base film>breaking elongation rate of the decorative layer>breaking elongation rate of the conductive layer.
8. The molded film according to claim 6 , wherein the base film is a film selected from polycarbonate, polymethylmethacrylate, and polyethylene terephthalate, or a laminated film of polycarbonate, polymethylmethacrylate, and polyethylene terephthalate.
9. A molded article in which a conductive layer is laminated on a base material, wherein the conductive layer is a cured product of the conductive composition for molded film according to claim 1 .
10. A production method of a molded article, comprising:
producing a molded film by printing and drying the conductive composition for molded film according to claim 1 on a base film;
arranging the molded film on a base material; and
integrating the molded film and the base material by an overlay molding method.
11. A production method of a molded article, comprising:
producing a molded film by printing and drying the conductive composition for molded film according to claim 1 on a base film;
molding the molded film into a predetermined shape;
arranging the molded film that has been molded in a mold for injection molding; and
molding a base material by injection molding, and integrating the molded film and the base material.
12. A production method of a molded article, comprising:
producing a molded film by printing and drying the conductive composition for molded film according to claim 1 on a base film;
arranging the molded film in a mold for injection molding; and
molding a base material by injection molding, and transferring a conductive layer in the molded film to a base material side.