Provided is a resin composition for an acoustic matching layer, the resin composition including metal particles (A), an epoxy resin (B), a polythiol compound (C), and a cure-accelerating compound (D). The epoxy resin (B) includes at least one epoxy resin selected from the group consisting of bisphenol A epoxy resins, bisphenol F epoxy resins, and phenol novolac epoxy resins, and the polythiol compound (C) includes a compound having at least two specific partial structures. Also provided are a cured product formed of the composition, an acoustic matching sheet, an acoustic probe, an acoustic measuring apparatus, and a method for producing an acoustic probe. Further provided is an acoustic matching layer material set suitable for preparation of the composition.

A curable composition including a first compound having a group represented by general formula (x) and an epoxy group and having a molecular weight of 1000 or less. In the general formula (x), Rf.sub.1 and Rf.sub.2 each independently represent a fluorine-containing alkyl group.

—C(Rf.sub.1)(Rf.sub.2)—OH  (x)

A curable composition including a first compound having a group represented by general formula (x) and an epoxy group and having a molecular weight of 1000 or less. In the general formula (x), Rf.sub.1 and Rf.sub.2 each independently represent a fluorine-containing alkyl group.

—C(Rf.sub.1)(Rf.sub.2)—OH  (x)

To provide an epoxy resin composition that exhibits excellent low-dielectric properties and that is excellent in copper foil peel strength and interlayer cohesion strength in a printed-wiring board application, as well as an active ester resin that provides the epoxy resin composition. An active ester resin having a polyaryloxy unit containing a dicyclopentenyl group and represented by the following formula (1), and a polyarylcarbonyl unit. Here, R.sup.1 represents a hydrocarbon group having 1 to 8 carbon atoms, R.sup.2 represents a hydrogen atom, or formula (1a) or formula (1b), and at least one R.sup.2 is formula (1a) or formula (1b); and n represents a number of repetitions of 1 to 5.

##STR00001##

To provide an epoxy resin composition that exhibits excellent low-dielectric properties and that is excellent in copper foil peel strength and interlayer cohesion strength in a printed-wiring board application, as well as an active ester resin that provides the epoxy resin composition. An active ester resin having a polyaryloxy unit containing a dicyclopentenyl group and represented by the following formula (1), and a polyarylcarbonyl unit. Here, R.sup.1 represents a hydrocarbon group having 1 to 8 carbon atoms, R.sup.2 represents a hydrogen atom, or formula (1a) or formula (1b), and at least one R.sup.2 is formula (1a) or formula (1b); and n represents a number of repetitions of 1 to 5.

##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##

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##

Provided herein is a polymer composition comprising a polyhydroxyamino ether (e.g., a crosslinked polyhydroxyamino ether) and printed circuit boards comprising the same.

Provided herein is a polymer composition comprising a polyhydroxyamino ether (e.g., a crosslinked polyhydroxyamino ether) and printed circuit boards comprising the same.

Structural adhesive films are presented which comprise branched or networked polymers which are the reaction product of one or more polyether sulfone polymers, which may include amine-terminated polyether sulfone polymers and/or hydroxy-terminated polyether sulfone polymers, with epoxy-functional chemical species including the reaction product of one or more first polyepoxides with an amine-terminated branched polytetrahydrofuran polymer. The structural adhesive films may possess high strength, holding power and durability in high-temperature applications.