Provided is a curable composition having excellent workability and being capable of forming a cured product having excellent heat resistance. The curable composition of the present invention includes a compound represented by Formula (1) below and a solvent: In Formula (1) below, R.sup.1 and R.sup.2 each represent a curable functional group, and D.sup.1 and D.sup.2 each represent a single bond or a linking group. L represents a divalent group having a repeating unit containing a structure represented by Formula (I) below and a structure represented by Formula (II) below. In Formula (I) and Formula (II) below, Ar.sup.1 to Ar.sup.3 each represent a group in which two hydrogen atoms are removed from an aromatic ring structure or a group in which two hydrogen atoms are removed from a structure in which two or more aromatic rings are bonded through a single bond or a linking group. X represents —CO—, —S—, or —SO.sub.2—, and Y represents —S—, —SO.sub.2—, —O—, —CO—, —COO—, or —CONH—. n represents an integer of 0 or greater.

Provided is a maleimide resin with superior solution stability. Also provided is a cured product with a superior dielectric characteristic that is obtained by curing a curable resin composition in which said maleimide resin is used. The maleimide resin expressed in formula (1). (In formula (1), each of the plurality of Rs independently represents a C1-5 alkyl group, n is the number of repetitions, and the average value thereof is 1<n<5.)

A thermoplastic polymer-based composite material and a preparation method thereof are provided. The thermoplastic polymer-based composite material is obtained by impregnating a reinforcing material with a mixture or oligomer of an epoxy resin, a bismaleimide resin, and a bifunctional amine (calculated based on active hydrogen), and then performing an in-situ polymerization. The thermoplastic polymer-based composite material has excellent impregnation effect, excellent secondary processing performance, relatively high heat resistance, excellent flame retardancy, and mechanical properties, and excellent comprehensive performance.

Provided is a maleimide resin with superior solution stability. Also provided is a cured product with a superior dielectric characteristic that is obtained by curing a curable resin composition in which said maleimide resin is used. The maleimide resin expressed in formula (1), wherein the N,N′-(phenylene-di-(2,2,-propylidene)-di-p-phenylene) bismaleimide content is 90 area % or less. (In formula (1), n is the number of repetitions, and 1<n<5.)

The disclosure provides a thermosetting resin composition which contains at least: (a) a benzoxazine resin and (b) bismaleimide. The disclosure provides a flame-retardant resin composition which contains at least: (a) a benzoxazine resin, (b) bismaleimide, and (c) a flame retardant. The thermosetting resin composition and the flame-retardant resin composition may be used as a constituent element of a semiconductor liquid packaging material, or an interlayer insulating film.

A modified bismaleimide resin, a method for preparing the same, a prepreg, a copper clad laminate, and a printed circuit board are provided. The modified bismaleimide resin is formed by reacting a diamine having a specific structure with maleic anhydride, and has greater amounts of non-polar and hydrophobic groups in the molecular structure thereof.

Provided is a multilayered transmission line plate including one pair of ground layers, a differential wiring layer disposed between one ground layer and the other ground layer of the one pair of ground layers, a first insulating portion disposed between the differential wiring layer and the one ground layer, and a second insulating portion disposed between the differential wiring layer and the other ground layer, wherein the first insulating portion has a resin layer, the first insulating portion or the second insulating portion has a fiber base material layer including a fiber base material, and a thickness of the first insulating portion is equal to or thinner than a thickness of the second insulating portion.

A method for producing a polyimide precursor having a structural unit represented by the following formula (1), comprising the following steps (i) and (ii), wherein at least one of the steps of (i) and (ii) is carried out in a solvent comprising a compound having an ether bond and an amide bond: (i) a step of reacting carboxylic anhydride with a diamine compound to obtain a polyimide precursor having a structural unit represented by the following formula (2); and (ii) a step of reacting the polyimide precursor having a structural unit represented by the formula (2) with a compound represented by the following formula (8), and reacting the reactant with a compound represented by the following formula (9) to obtain a polyimide precursor having a structural unit represented by the following formula (1):

##STR00001## wherein in the formula (1), at least one of R.sub.1 and R.sub.2 is a group represented by the formula (3):

##STR00002##

Provided are a novel aromatic bismaleimide compound capable of being turned into a film without using a film-forming agent, and dissolved even in a solvent other than a high-boiling aprotic polar solvent; a production method of such compound; and a heat-curable cyclic imide resin composition that contains such compound, and is capable of being cured at a low temperature and turned into a cured product superior in mechanical properties, heat resistance, relative permittivity, dielectric tangent, moisture resistance and adhesiveness. The aromatic bismaleimide compound is represented by the following formula (1):

##STR00001##

wherein X1 independently represents a divalent group, m represents a number of 1 to 30, n represents a number of 1 to 5, each of A.sup.1 and A.sup.2 independently represents a divalent aromatic group. The heat-curable cyclic imide resin composition contains the above compound as a component (A), a reaction initiator (B) and an organic solvent (C).

A polyimide precursor resin composition for forming a flexible device substrate, including a polyamic acid having a structure obtained from a tetracarboxylic acid component including at least one of 3,3,4,4-biphenyltetracarboxylic dianhydride and pyromellitic dianhydride, a diamine component including at least one of paraphenylene diamine and 4,4-diaminodiphenyl ether, and a carboxylic acid monoanhydride, the polyamic acid satisfying equations (1) and (2) below:

0.97X/Y<1.00Equation (1)

0.5(Z/2)/(YX)1.05Equation (2)

in which X represents a number of moles of tetracarboxylic acid component, Y represents a number of moles of diamine component, and Z represents a number of moles of the carboxylic acid monoanhydride.