An insulated wire, containing a conductor, and an insulating film provided on the periphery of the conductor, in which the insulating film contains a polyimide resin, and the polyimide resin contains the following constituting unit (a) as a tetracarboxylic dianhydride-derived constituting unit and the following constituting unit (b) as a diamine-derived constituting unit, among the constituting units of the polyimide: (a) a constituting unit having a skeleton derived from pyromellitic anhydride and/or a constituting unit having a skeleton derived from 3,3,4,4-biphenyltetracarboxylic dianhydride; and (b) a constituting unit having a skeleton derived from 9,9-bis(4-aminophenyl)fluorene.

The invention discloses a preparation method of a polyimide film having a low dielectric constant and high fracture toughness; in the method an aromatic diamine solution is firstly prepared, and then a poly(5-norbornene-2,3-dicarboxylic anhydride-alt-maleimide isobutyl polyhedral oligomeric silsesquioxane) and aromatic dianhydride are ground, uniformly mixed, added to the aromatic diamine solution, and stirred to obtain a poly(5-norbornene-2,3-dicarboxylic anhydride-alt-maleimide isobutyl polyhedral oligomeric silsesquioxane)/polyamic acid solution; the solution is uniformly applied on a clean glass sheet, then placed in a vacuum drying oven, cooled to room temperature, and then a film is peeled off in water by ultrasonic and dried under vacuum to obtain the desired product. The dielectric constant of the film obtained by the invention is reduced to 2.2, and the elongation at break is increased by 272%, the tensile breaking energy is increased by 285%, showing greatly improved elongation at break and fracture energy, and good fracture toughness.

The present invention provides: a method for manufacturing a polyimide film for a graphite sheet having improved thermal conductivity; and the polyimide film. The present invention also provides a graphite sheet having excellent thermal conductivity, which is manufactured using the polyimide film.

A fixing belt member includes a base layer. The base layer contains a polyimide-based resin composition and at least one type of particles selected from the group consisting of acetylene black particles and graphitized carbon black particles.

In a first aspect, a polymer film includes a polyimide. The polyimide includes one or more dianhydrides and one or more diamines. Each of the dianhydrides and diamines is selected from the group consisting of crankshaft monomers, flexible monomers, rigid rotational monomers, rigid non-rotational monomers, and rotational inhibitor monomers. The polymer film has a D.sub.f of 0.005 or less, a water absorption of 2.0% or less and a water vapor transport rate of 50 (gmil)/(m.sup.2day) or less. In a second aspect, a metal-clad laminate includes the polymer film of first aspect and a first metal layer adhered to a first outer surface of the polymer film. In a third aspect, an electronic device includes the polymer film of the first aspect.

A polyimide containing a repeating unit represented by the following formula (I) and a repeating unit represented by the following formula (II).

##STR00001##

In the formula (II), R each independently represents a hydrogen atom, a fluorine atom, or a methyl group.

Provided is a fiber-reinforced thermoplastic resin prepreg which exhibits high interfacial adhesion between reinforcement fibers and a matrix resin, while having excellent interlaminar fracture resistance. The fiber-reinforced thermoplastic resin prepreg of the present invention comprises: a matrix resin comprising a polyarylketone resin and a polyetherimide resin; and a carbon fiber, wherein the polyetherimide resin in the matrix resin comprises a polyetherimide resin having a structural unit represented by Formula (1), an amount of the polyetherimide resin in the matrix resin (100% by mass) is 3% by mass to 25% by mass, and an amount of the polyarylketone resin in the matrix resin (100% by mass) is 75% by mass or more.

##STR00001##

In various aspects, a polymer resin is provided for vat photopolymerization. The resin can include a polyamic acid salt formed from the addition of a photocrosslinkable amine to a polyamic acid. The resin can include a photoinitiator suitable for initiating crosslinking of the photocrosslinkable amine when exposed to a light source of a suitable wavelength and intensity. The polyamic acid can be formed, for instance, by the addition of a diamine to a suitable dianhydride. Methods of additive manufacturing using the resins are also provided.

The purpose of the present invention is to provide a resin composition which enables the achievement of a cured film that has a low dielectric loss tangent and is capable of withstanding a heat treatment and a chemical treatment, said treatments being associated with the formation of a coil pattern. In order to achieve the above-described purpose, the configuration of the present invention is as follows. A resin composition which contains (P) a resin that has an alicyclic structure and an aromatic ring structure, and wherein the resin (P) that has an alicyclic structure and an aromatic ring structure has a group having two or more alicyclic rings and a group wherein two or more benzene rings are bonded by means of a single bond.

The present invention provides a process for producing a polymer film at high productivity: during a process for drying gripped portions of both edges of a gel film, a first heat treatment is performed by blowing hot air in the film width direction and a second heat treatment is performed by blowing hot air at gripped portions of both edges of the gel film in a direction parallel to the film running direction.