A compound (A) of the present invention is represented by the formula (1): wherein each R.sub.1 independently represents a group represented by the formula (2) or a hydrogen atom, and each R.sub.2 independently represents a hydrogen atom or a linear or branched alkyl group having 1 to 6 carbon atoms, provided that at least one R.sub.1 is a group represented by the formula (2); and wherein -* represents a bonding hand.

An object of the present invention is to reduce or eliminate a defect (e.g., a void) by achieving (i) a semipreg and a prepreg each of which allows a reduction in residual volatile component and (ii) methods for producing the semipreg and the prepreg, respectively, and consequently to achieve (iii) a fiber-reinforced composite material which has high heat resistance and superior mechanical strength and a (iv) a method for producing the fiber-reinforced composite material. The present invention attains the above object by providing, for example, a semipreg containing: powders of an imide oligomer; and reinforcement fibers, the imide oligomer being represented by a specific general formula (1).

An object of the present invention is to reduce or eliminate a defect (e.g., a void) by achieving (i) a semipreg and a prepreg each of which allows a reduction in residual volatile component and (ii) methods for producing the semipreg and the prepreg, respectively, and consequently to achieve (iii) a fiber-reinforced composite material which has high heat resistance and superior mechanical strength and a (iv) a method for producing the fiber-reinforced composite material. The present invention attains the above object by providing, for example, a semipreg containing: powders of an imide oligomer; and reinforcement fibers, the imide oligomer being represented by a specific general formula (1).

A modified polyimide resin containing a structure represented by general formula (I) below. A polyimide resin containing: a structural unit A derived from a tetracarboxylic dianhydride; and a structural unit B derived from a diamine compound, wherein the structural unit A contains a structural unit derived from a compound having a specific structure in a proportion of 60 mol % or greater.

##STR00001##

[Problem] Provided is a resin composition, resin sheet, prepreg and printed wiring board capable of obtaining excellent low permittivity, low dielectric loss tangent, flexibility and peel strength.

[Solution Means] A resin composition containing (A) a maleimide compound exhibiting a relative permittivity of lower than 2.7, (B) a polyphenylene ether compound represented by general formula (1) below and having a number-average molecular weight of 1000 to 7000, and (C) a block copolymer with a styrene skeleton. In general formula (1), X represents an aryl group, —(Y—O)n.sub.2- represents a polyphenylene ether portion, R.sub.1, R.sub.2 and R.sub.3 each independently represent a hydrogen atom or an alkyl, alkenyl or alkynyl group, n.sub.2 represents an integer of 1 to 100, n.sub.1 represents an integer of 1 to 6 and n.sub.3 represents an integer of 1 to 4.

##STR00001##

Provided is a resin composition having excellent low water absorption, as well as a cured product, a prepreg, a metal foil-clad laminate, a resin sheet, and a printed wiring board. The resin composition contains a compound (A) represented by Formula (M1) and a compound (B) containing two or more unsaturated carbon-carbon double bonds, and in Formula (M1), A is a four- to six-membered alicyclic group:

##STR00001##

An amide compound and a nitrogen-containing heterocyclic ring-containing compound which have a specific repeating unit and a crosslinking site represented by Formula (2):

—C≡CX.sup.1

at a molecular end.

A resin composition includes 100 parts by weight of a prepolymer and 100 parts by weight to 250 parts by weight of a spherical silica prepared by vaporized metal combustion, wherein: the prepolymer is prepared by subjecting a reaction mixture to a prepolymerization reaction; the reaction mixture includes a maleimide resin, an amino-modified silicone and cyclohexanone, and relative to a total of 100 parts by weight of the maleimide resin, the amino-modified silicone and the cyclohexanone, the reaction mixture includes 60 parts by weight to 80 parts by weight of the maleimide resin, 15 parts by weight to 30 parts by weight of the amino-modified silicone and 2 parts by weight to 15 parts by weight of the cyclohexanone; the reaction mixture does not include m-aminophenol or p-aminophenol; and the amino-modified silicone has an amino equivalent of 750 g/mol to 2500 g/mol. The resin composition may be used to make various articles, such as a prepreg, a resin film, a laminate or a printed circuit board, and at least one of the following improvements can be achieved, including varnish transparency, varnish sedimentation property, glass transition temperature, X-axis coefficient of thermal expansion, T300 thermal resistance, resin cluster and resin filling property.

A curable photosensitive resin composition which can be cured at a relatively low temperature, has excellent developability and adhesion to a support, and a cured product that realizes low dielectric constant properties. A curable photosensitive resin composition containing a polyimide resin (A) which is a reaction product of monomer groups containing an aromatic tetracarboxylic anhydride (a1) and a diamine (a2) containing a dimer diamine, maleimides (B), and a polyfunctional polymerizable compound (C) having two or more ethylenic double bonds other than the component (A) and the component (B), a cured product, a photosensitive element, a resist pattern, a method of producing a resist pattern, a semiconductor device and an electronic device.

A photosensitive resin composition comprising (A) a polyimide precursor having a polymerizable unsaturated bond; (B) a polymerizable monomer having an aliphatic cyclic skeleton; (C) a photopolymerization initiator; and (D) a solvent.