Abstract: An insulated wire including: a linear conductor; and an insulating layer that covers an outer peripheral surface of the conductor, wherein the insulating layer contains, as residual solvents, a first solvent having a relative permittivity of 15 or more and a second solvent having a relative permittivity of less than 15, a first ratio that is a ratio of a content of the second solvent to a total content of the first solvent and the second solvent contained in the insulating layer is 50% by mass or more, and a second ratio that is a ratio of the content of the second solvent to the total content of the first solvent and the second solvent contained in the insulating layer after a heating treatment of heating the insulated wire at 350° C. for 1 minute is higher than the first ratio.

Abstract: An insulated wire comprising a conductor and an insulating layer covering the conductor, wherein: the insulating layer comprises a resin and a first filler; the resin comprises a polyimide; the first filler is present in the form of a primary particle or a secondary particle having a plurality of the primary particles aggregated; the primary particle is a silica or alumina particle; the secondary particle has a particle diameter of 0.03 ?m or more and 5 ?m or less; and the percentage of the total area of the secondary particles to the sum of the total area of the primary particles and the total area of the secondary particles in the cross section of the insulated wire is 50% or more.

Abstract: The resin composition according to one aspect is a resin composition containing a polyamic acid and a solvent, wherein the polyamic acid has a repeating unit represented by the following general formula (1) in a molecular chain, and the molecular chain has a structure represented by the following general formula (2) at one end or both ends. The proportion of the structure represented by the following general formula (2) relative to 1 mol of the repeating unit represented by the following general formula (1) is 0.001 mol or more and 0.1 mol or less. In the following general formulas, R1 is a tetravalent organic group; R2 is a divalent organic group; and R3 is an organic group having 15 or less carbon atoms.

Abstract: An insulated electrical cable includes: a conductor; and an insulating layer that is laminated on an outer peripheral surface of the conductor and includes a polyimide as a main component, wherein the insulating layer includes a plurality of pores, and wherein a porosity of the insulating layer is greater than or equal to 25% by volume and less than or equal to 60% by volume.

Abstract: A method for producing an insulated electric wire includes a step of preparing a conductor having a linear shape; a step of forming an insulating coating so as to cover a surface on an outer peripheral side of the conductor to obtain an insulated electric wire that includes the conductor and the insulating coating covering the conductor; and a step of measuring a first electrostatic capacity between the insulated electric wire and a first electrode disposed outside in a radial direction of the insulated electric wire so as to face an outer peripheral surface of the insulated electric wire while transporting the insulated electric wire in a longitudinal direction of the conductor, and inspecting a formation state of the insulating coating, the formation state including a formation state of a defective portion in the insulating coating, on the basis of a change in the first electrostatic capacity.

Abstract: An insulated electric wire includes a linear conductor and one or a plurality of insulating layers formed on an outer peripheral surface of the conductor. At least one of the one or plurality of insulating layers contains a plurality of pores, outer shells are disposed on peripheries of the pores, and the outer shells are derived from shells of hollow-forming particles having a core-shell structure. A varnish for forming an insulating layer contains a resin composition forming a matrix and hollow-forming particles having a core-shell structure and dispersed in the resin composition. In the varnish, cores of the hollow-forming particles contain a thermally decomposable resin as a main component, and shells of the hollow-forming particles contain a main component having a higher thermal decomposition temperature than the thermally decomposable resin.

Abstract: An insulated electrical cable according to one aspect of the present invention is an insulated electrical cable including: a conductor; and an insulating layer that is laminated on an outer peripheral surface of the conductor and includes a polyimide as a main component, wherein the insulating layer includes a plurality of pores, and wherein a porosity of the insulating layer is greater than or equal to 25% by volume and less than or equal to 60% by volume.

Abstract: An insulated electric wire includes a linear conductor and an insulating film disposed to surround the periphery of the conductor. The insulating film includes a polyimide layer formed of a polyimide that has a molecular structure including a PMDA-ODA-type repeating unit A and a BPDA-ODA-type repeating unit B, the mole fraction [B×100/(A+B)] (% by mole) represented by the percentage of the number of moles of the repeating unit B to the total number of moles of the repeating unit A and the repeating unit B being 25% or more by mole and 95% or less by mole. The polyimide layer has a plurality of pores. The pores occupy 5% or more by volume and 80% or less by volume of the polyimide layer.

Abstract: An insulated electric wire includes a conductor that has a linear shape and an insulating film that is formed to cover the periphery of the conductor. The insulating film is formed of a polyimide that has a molecular structure including a PMDA-ODA-type repeating unit A and a BPDA-ODA-type repeating unit B, the mole ratio [B/(A+B)]×100 (% by mole) of the number of moles of the repeating unit B to the total number of moles of the repeating unit A and the repeating unit B being more than 55% by mole. A first sample of the insulating film with a separation elongation of 7% has a ratio M60/M10 of 1.2 or more, or a second sample of the insulating film with a separation elongation of 40% has a ratio M30/M10 of 1.2 or more.

Abstract: An insulated wire according to one embodiment of the present invention includes a linear conductor, and one or a plurality of insulating layers that are laminated on an outer peripheral surface of the conductor, wherein at least one layer of the one or plurality of insulating layers includes a plurality of pores, and a closed porosity within the plurality of pores is 80% by volume or higher.

Abstract: A method for producing an insulated electric wire includes a step of preparing a conductor having a linear shape; a step of forming an insulating coating so as to cover a surface on an outer peripheral side of the conductor to obtain an insulated electric wire that includes the conductor and the insulating coating covering the conductor; and a step of measuring a first electrostatic capacity between the insulated electric wire and a first electrode disposed outside in a radial direction of the insulated electric wire so as to face an outer peripheral surface of the insulated electric wire while transporting the insulated electric wire in a longitudinal direction of the conductor, and inspecting a formation state of the insulating coating, the formation state including a formation state of a defective portion in the insulating coating, on the basis of a change in the first electrostatic capacity.

Abstract: An insulated wire according to one embodiment of the present invention includes a linear conductor, and one or a plurality of insulating layers that are laminated on an outer peripheral surface of the conductor, wherein at least one layer of the one or plurality of insulating layers includes a plurality of pores, and a closed porosity within the plurality of pores is 80% by volume or higher.

Abstract: A first embodiment of a substrate for a high-frequency printed wiring board according to the present disclosure is directed to a substrate for a high-frequency printed wiring board, the substrate including: a dielectric layer including a fluororesin and an inorganic filler; and a copper foil layered on at least one surface of the dielectric layer, wherein a surface of the copper foil at the dielectric layer side has a maximum height roughness (Rz) of less than or equal to 2 ?m, and a ratio of the number of inorganic atoms of the inorganic filler to the number of fluorine atoms of the fluororesin in a superficial region of the dielectric layer at the copper foil side is less than or equal to 0.08.

Abstract: An insulated electric wire includes a linear conductor and one or more of insulating layers formed on an outer peripheral surface of the conductor. In the insulated electric wire, at least one of the one or more of insulating layers has a plurality of pores, outer shells are disposed on peripheries of the pores, and each of the outer shells has a plurality of projections on an outer surface thereof.

Abstract: A first embodiment of a substrate for a high-frequency printed wiring board according to the present disclosure is directed to a substrate for a high-frequency printed wiring board, the substrate including: a dielectric layer including a fluororesin and an inorganic filler; and a copper foil layered on at least one surface of the dielectric layer, wherein a surface of the copper foil at the dielectric layer side has a maximum height roughness (Rz) of less than or equal to 2 ?m, and a ratio of the number of inorganic atoms of the inorganic filler to the number of fluorine atoms of the fluororesin in a superficial region of the dielectric layer at the copper foil side is less than or equal to 0.08.

Abstract: An insulated electric wire includes a linear conductor and one or more of insulating layers formed on an outer peripheral surface of the conductor. In the insulated electric wire, at least one of the one or more of insulating layers has a plurality of pores, outer shells are disposed on peripheries of the pores, and each of the outer shells has a plurality of projections on an outer surface thereof.

Abstract: An insulated electric wire includes a linear conductor and one or a plurality of insulating layers formed on an outer peripheral surface of the conductor. At least one of the one or plurality of insulating layers contains a plurality of pores, outer shells are disposed on peripheries of the pores, and the outer shells are derived from shells of hollow-forming particles having a core-shell structure. A varnish for forming an insulating layer contains a resin composition forming a matrix and hollow-forming particles having a core-shell structure and dispersed in the resin composition. In the varnish, cores of the hollow-forming particles contain a thermally decomposable resin as a main component, and shells of the hollow-forming particles contain a main component having a higher thermal decomposition temperature than the thermally decomposable resin.

Abstract: An insulating varnish forms an insulating coating film having a shape that corresponds to the shape of an opening of a die, having a uniform thickness. The insulating varnish is applied onto a surface of a conductor, subsequently passes through a die to remove the excess applied insulating varnish, and is then dried or baked to form an insulating coating film on the surface of the conductor. The insulating varnish has a viscosity of 10 Pa·s or more measured by a B-type viscometer at 30° C. The insulating varnish preferably contains no filler, and is preferably a polyimide precursor solution. Since the insulating varnish has a high viscosity, baking and solidification can be performed while maintaining a shape formed when the insulating varnish passes through a die.

Abstract: An insulating varnish forms an insulating coating film having a shape that corresponds to the shape of an opening of a die, having a uniform thickness. The insulating varnish is applied onto a surface of a conductor, subsequently passes through a die to remove the excess applied insulating varnish, and is then dried or baked to form an insulating coating film on the surface of the conductor. The insulating varnish has a viscosity of 10 Pa·s or more measured by a B-type viscometer at 30° C. The insulating varnish preferably contains no filler, and is preferably a polyimide precursor solution. Since the insulating varnish has a high viscosity, baking and solidification can be performed while maintaining a shape formed when the insulating varnish passes through a die.

Abstract: A first embodiment of a substrate for a high-frequency printed wiring board according to the present disclosure is directed to a substrate for a high-frequency printed wiring board, the substrate including: a dielectric layer including a fluororesin and an inorganic filler; and a copper foil layered on at least one surface of the dielectric layer, wherein a surface of the copper foil at the dielectric layer side has a maximum height roughness (Rz) of less than or equal to 2 ?m, and a ratio of the number of inorganic atoms of the inorganic filler to the number of fluorine atoms of the fluororesin in a superficial region of the dielectric layer at the copper foil side is less than or equal to 0.08.