A negative-working photosensitive resin composition including an epoxy group-containing resin, a metal oxide, and a cationic polymerization initiator, in which a photosensitive resin film having a film thickness of 20 μm obtained by applying the negative-working photosensitive resin composition onto a silicon wafer and performing a bake treatment at 90° C. for 5 minutes has a Martens hardness of less than 235 [N/mm.sup.2], and when a viscoelasticity of a cured film, which is obtained by exposing the photosensitive resin film to i-rays at an irradiation amount of 200 mJ/cm.sup.2, performing a bake treatment after the exposure at 90° C. for 5 minutes, and then performing a bake treatment at 200° C. for 1 hour to cure the photosensitive resin film, is measured at a frequency of 1.0 Hz, a tensile elastic modulus (E*) of the cured film at a temperature of 175° C. is 2.1 [GPa] or more.

A negative-working photosensitive resin composition including an epoxy group-containing resin, a metal oxide, and a cationic polymerization initiator, in which a photosensitive resin film having a film thickness of 20 μm obtained by applying the negative-working photosensitive resin composition onto a silicon wafer and performing a bake treatment at 90° C. for 5 minutes has a Martens hardness of less than 235 [N/mm.sup.2], and when a viscoelasticity of a cured film, which is obtained by exposing the photosensitive resin film to i-rays at an irradiation amount of 200 mJ/cm.sup.2, performing a bake treatment after the exposure at 90° C. for 5 minutes, and then performing a bake treatment at 200° C. for 1 hour to cure the photosensitive resin film, is measured at a frequency of 1.0 Hz, a tensile elastic modulus (E*) of the cured film at a temperature of 175° C. is 2.1 [GPa] or more.

Problem: To provide a molded article for laser welding which has excellent visible light transmittance and laser transmittance and in which variation in laser transmittance is suppressed, and an agent for suppressing variation in laser transmittance of a molded article for laser welding.

Solution: A molded article for laser welding comprising a polybutylene terephthalate resin composition containing 100 parts by mass of (A) a polybutylene terephthalate resin, (B) a polycarbonate resin in which the melt viscosity at 300° C. and a shear rate of 1000 sec.sup.−1 is 0.20 kPa.Math.s or greater, and 1 part by mass or greater and 10 parts by mass or less of (C) an epoxy-based compound, the molded article having a thickness at a welded part of 1.3 mm or greater, and an agent for suppressing variation in laser transmittance of a molded article for laser welding, the agent containing an epoxy-based compound.

Problem: To provide a molded article for laser welding which has excellent visible light transmittance and laser transmittance and in which variation in laser transmittance is suppressed, and an agent for suppressing variation in laser transmittance of a molded article for laser welding.

Solution: A molded article for laser welding comprising a polybutylene terephthalate resin composition containing 100 parts by mass of (A) a polybutylene terephthalate resin, (B) a polycarbonate resin in which the melt viscosity at 300° C. and a shear rate of 1000 sec.sup.−1 is 0.20 kPa.Math.s or greater, and 1 part by mass or greater and 10 parts by mass or less of (C) an epoxy-based compound, the molded article having a thickness at a welded part of 1.3 mm or greater, and an agent for suppressing variation in laser transmittance of a molded article for laser welding, the agent containing an epoxy-based compound.

An object of the present invention is to provide an epoxy resin composition that can be preferably used for prepreg and fiber reinforced composite material applications and is excellent in elastic modulus, strength, and pot life. The present invention is the epoxy resin composition including the following components [A] to [C] and satisfying the following conditions (1) to (4):

[A]: epoxy resin
[B]: aromatic diamine
[C]: a compound having a boiling point of 130° C. or more and a molecular weight m of 50 or more and 250 or less, the compound having no epoxy group in the molecule and having substantially no curing ability of an epoxy resin (1): the ratio H/E between the amount by mole, E, of the epoxy group in the component [A] and the amount by mole, H, of active hydrogen in the component [B] is 0.50 or more and 1.30 or less. (2): at least a part of the component [C] satisfies 0.10 or more and 0.60 or less in a ratio m/M of a molecular weight m thereof to a theoretical molecular weight between crosslinking points, M, of a cured product of the epoxy resin composition. (3): the ratio C/E of the amount by mole, E, for epoxy groups of the component [A] to the amount by mole, C, of the component [C] satisfying the condition (2) is 0.01 or more and 0.20 or less; and (4): the viscosity at 70° C. for 2 hours is 5.0 times or less the initial viscosity at 70° C.

An object of the present invention is to provide an epoxy resin composition that can be preferably used for prepreg and fiber reinforced composite material applications and is excellent in elastic modulus, strength, and pot life. The present invention is the epoxy resin composition including the following components [A] to [C] and satisfying the following conditions (1) to (4):

[A]: epoxy resin
[B]: aromatic diamine
[C]: a compound having a boiling point of 130° C. or more and a molecular weight m of 50 or more and 250 or less, the compound having no epoxy group in the molecule and having substantially no curing ability of an epoxy resin (1): the ratio H/E between the amount by mole, E, of the epoxy group in the component [A] and the amount by mole, H, of active hydrogen in the component [B] is 0.50 or more and 1.30 or less. (2): at least a part of the component [C] satisfies 0.10 or more and 0.60 or less in a ratio m/M of a molecular weight m thereof to a theoretical molecular weight between crosslinking points, M, of a cured product of the epoxy resin composition. (3): the ratio C/E of the amount by mole, E, for epoxy groups of the component [A] to the amount by mole, C, of the component [C] satisfying the condition (2) is 0.01 or more and 0.20 or less; and (4): the viscosity at 70° C. for 2 hours is 5.0 times or less the initial viscosity at 70° C.

Provided is a method for producing a material that suppresses a decrease in the life of an insulation against surge voltage, that is, a material that provides a long dielectric breakdown lifetime. The method is a method for producing a fullerene-derivative-containing resin composition containing a fullerene derivative and a resin that has an affinity for a polar solvent, including: a step (I) of dispersing a fullerene derivative in a polar solvent; and a step (II) of mixing the polar solvent in which the fullerene derivative is dispersed with a resin that has an affinity for the polar solvent.

Provided is a method for producing a material that suppresses a decrease in the life of an insulation against surge voltage, that is, a material that provides a long dielectric breakdown lifetime. The method is a method for producing a fullerene-derivative-containing resin composition containing a fullerene derivative and a resin that has an affinity for a polar solvent, including: a step (I) of dispersing a fullerene derivative in a polar solvent; and a step (II) of mixing the polar solvent in which the fullerene derivative is dispersed with a resin that has an affinity for the polar solvent.

Disclosed are a magnetic coating material, a magnetic sheet, and a metal compatible tag that have excellent magnetic shielding characteristics against radio waves in the UHF band and do not interfere with a distribution process. A magnetic coating material includes a magnetic filler and a binder resin, wherein the magnetic filler is an Fe—Cr alloy, and wherein in a magnetic sheet formed from the magnetic coating material, complex relative permeability in 860 MHz to 960 MHz has a loss factor tan δ of 0.3 or less and a real part μ′ of 5 or more. Also, a magnetic coating material includes a magnetic filler and a binder resin, wherein the magnetic filler is an Fe—Cr alloy, and wherein a mass ratio of the magnetic filler to a solid content of the binder (mass of the magnetic filler/mass of the solid content of the binder) is from 70/30 to 95/5.

Disclosed are a magnetic coating material, a magnetic sheet, and a metal compatible tag that have excellent magnetic shielding characteristics against radio waves in the UHF band and do not interfere with a distribution process. A magnetic coating material includes a magnetic filler and a binder resin, wherein the magnetic filler is an Fe—Cr alloy, and wherein in a magnetic sheet formed from the magnetic coating material, complex relative permeability in 860 MHz to 960 MHz has a loss factor tan δ of 0.3 or less and a real part μ′ of 5 or more. Also, a magnetic coating material includes a magnetic filler and a binder resin, wherein the magnetic filler is an Fe—Cr alloy, and wherein a mass ratio of the magnetic filler to a solid content of the binder (mass of the magnetic filler/mass of the solid content of the binder) is from 70/30 to 95/5.