Provided is an adhesive composition that is capable of forming an adhesive layer having excellent electrical properties (low relative permittivity and low dielectric loss tangent) and excellent adhesiveness (adhesion properties) after heat curing, can improve adhesiveness (adhesion properties) in a laminating step, can prevent the peeling and lifting of layers during temporary fixing and roll-to-roll work, also has a high crosslink density, and does not cause heat resistance, solvent resistance and the like to deteriorate. The adhesive composition contains a bismaleimide resin and a styrene-based elastomer.

A polyphenylene ether resin modified with two amino functional groups, a method for producing the same, and a substrate material for a circuit board are provided. The polyphenylene ether resin modified with the two amino functional groups has a structural formula as follows:

##STR00001## in which R represents a chemical group that is located between two hydroxyphenyl functional groups of a bisphenol compound, and n is an integer between 3 and 25, inclusive.

A diamine monomer compound with a structural formula of

##STR00001##

wherein n.sub.1 is an integer greater than 1, forms the basis of a dielectric material with reduced dielectric losses for improved signals transmission. A method for preparing the compound, a polyimide resin made from the compound, a flexible film, and an electronic device including the polyimide resin are also disclosed. The compound has a long but flexible even numbered carbon chain and a liquid crystal unit structure. The reduced regularity and rigidity of the molecular chain make the polyimide resin convenient for film-forming. Dimensional stability is improved, the coefficient of thermal expansion of the materials is reduced, and the materials have good mechanical and thermal properties, the electron loss factor and coefficient of thermal expansion of the materials being reduced.

In a first aspect, a polyimide film includes a polyimide derived from a dianhydride and a diamine. The dianhydride includes pyromellitic dianhydride, the diamine includes a benzimidazole, the molar ratio of dianhydride to diamine that forms the polyimide is in a range of from 0.85:1 to 0.99:1, and the polyimide film has a T.sub.g of 400° C. or higher, a tensile modulus of 6.0 GPa or more, and a coefficient of thermal expansion of 15 ppm/° C. or less over a temperature range of 50 to 500° C. In a second aspect, an electronic device includes the polyimide film of the first aspect.

A low-dielectric heat dissipation film composition contains: (A) a maleimide resin composition containing (A1) a maleimide resin containing at least two or more maleimide groups per molecule and (A2) a polymerization initiator; and (B) boron nitride particles. The component (A1) has a maleimide equivalent of not more than 0.1 mol/100 g, and a cured material of the component (A) has a relative dielectric constant of 3.5 or less at a frequency of 10 GHz. Thus, the present invention provides a film composition for forming a film having low dielectric constant and high heat dissipation.

A metal substrate includes a first insulating substrate, a second insulating substrate, a first metal layer, a second metal layer and a release layer. The first insulating substrate has a first modified surface and a second surface opposite to the first modified surface. The first metal layer faces the second surface. The release layer is bonded on the first modified surface. The second insulating substrate is bonded on a side of the release layer, such that the release layer is between the first modified surface and the second insulating substrate. The second metal layer is disposed on a side of the second insulating substrate, such that the second insulating substrate is between the release layer and the second metal layer. An original surface roughness of the first modified surface has a variation substantially less than 10% after the first modified surface is released from the release layer.

An object of the present invention is to provide a liquid crystal polymer film having an excellent peel strength of a laminate produced by sticking a metal foil to the liquid crystal polymer film; and a laminate.

A liquid crystal polymer film including a liquid crystal polymer, in which in a case where a cross-section of the liquid crystal polymer film along a thickness direction of the liquid crystal polymer film is exposed and immersed in monomethylamine, and then void regions are extracted from an observed image of a cross-section obtained by using an electron microscope, an average value of widths of the void regions is 0.01 to 0.1 μm and an area ratio of the void regions in the observed image of the cross-section is 20% or less.

The present invention relates, in one aspect, to a thermosetting resin composition including an epoxy resin, an isocyanate resin, a polyrotaxane resin, and a curing agent, wherein the isocyanate resin includes a hexamethylene skeleton and at least one selected from a biuret skeleton, an isocyanurate skeleton, an allophanate skeleton, a neopentyl skeleton, a butylene skeleton, and a dicarboxyl skeleton in a structure thereof.

A polybenzimidazole production method for producing the polybenzimidazole including a repeating unit represented by the following formula (1):

##STR00001##

wherein R.sup.f is —SO.sub.2—, —O—, —CO—, an alkylene group optionally containing a substituent, or a group represented by the following formula (a):

##STR00002##

two Xs are each individually a hydrogen atom or a monovalent organic group; and R.sup.1 is a divalent organic group, the production method including a step (1-1) of polymerizing a tetramine compound and a dicarboxylic acid derivative compound to provide a polybenzimidazole precursor polyamide, and a step (1-2) of dehydrocyclizing the polybenzimidazole precursor polyamide.

The present disclosure relates to a polyimide-based polymer film comprising a polyimide-based polymer containing a polyimide repeating unit synthesized by the reaction of an acid anhydride compound having a specific structure and a diamine compound, wherein an average transmittance at a wavelength of 380 nm or more and 780 nm or less is 60% or more, and a thickness direction retardation value at a thickness of 10 pm is 150 nm or less, and a substrate for a display device, a circuit board, an optical device, and an electronic device using the same.