An epoxy resin, comprising an epoxy compound having a mesogenic structure, the epoxy compound comprising a first epoxy compound having one biphenyl structure in a molecule and a second epoxy compound that is different from the first epoxy compound, at a mass ratio of the first epoxy compound to the second epoxy compound (first epoxy compound:second epoxy compound) of from 10:100 to 50:100.

Provided is a gas barrier packaging material including a base and a cured resin layer, the base having a surface constituted of an inorganic substance. The cured resin layer is a cured product of an epoxy resin composition including an epoxy resin, an epoxy resin curing agent containing an amine-based curing agent, and an acidic compound, and a ratio (basic nitrogen/acid groups) of a molar equivalent of basic nitrogen in the epoxy resin composition to a molar equivalent of acid groups derived from the acidic compound is from 0.60 to 20.

The present invention provides an epoxy resin composition containing:

an epoxy resin [A] that is a compound represented by Chemical formula (1) shown below:

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wherein R.sub.1 to R.sub.4 each independently represent one selected from the group consisting of a hydrogen atom, an aliphatic hydrocarbon group, an alicyclic hydrocarbon group, and a halogen atom, and X represents one selected from —CH.sub.2—, —O—, —S—, —CO—, —C(═O)O—, —O—C(═O)—, —NHCO—, —CONH—, and —SO.sub.2—;

a bifunctional epoxy resin [B] having an amine type glycidyl group;

a curing agent [C] containing an aromatic polyamine, and having at least one substituent selected from an aliphatic substituent, an aromatic substituent, and a halogen atom at an ortho position with respect to an amino group; and

a particulate rubber component [D].

A curing agent for epoxy resins, including 1-amino-3-aminomethyl-3,5,5-trimethylcyclohexane and N-benzyl-1,2-ethandiamine in an amount for the ratio of the number of its amine hydrogens to be in the range of 90/10 to 20/80. The curing agent permits suitable epoxy resin compositions that have excellent workability and that cure particularly rapidly in cold and damp conditions, without blushing-induced surface defects, thus achieving coatings of in particular high hardness, high glass transition temperature and surprisingly little tendency to yellowing.

Provided is a curable resin composition exhibiting reduced or controlled shrinkage on curing. The composition includes (A) an epoxy resin, (B) a latent curing agent, and (C) a compound represented by formula (1):

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wherein X is an oxygen atom or a sulfur atom; R.sup.1 and R.sup.2 each independently represent a hydrogen atom, an alkyl group, or an aryl group; and R.sup.3 and R.sup.4 each independently represent a hydrogen atom, an alkyl group, or an aryl group, or R.sup.3 and R.sup.4 are connected to each other to represent a divalent group to form a ring.

Provided is an epoxy resin composition including an epoxy resin, an epoxy resin curing agent containing an amine-based curing agent, and an acidic compound, wherein a ratio (basic nitrogen/acid groups) of a molar equivalent of basic nitrogen in the epoxy resin composition to a molar equivalent of acid groups derived from the acidic compound is from 0.10 to 3.0. Also provided are a gas barrier film and a laminate in which the epoxy resin composition is used.

A resin composition for an acoustic matching layer; an acoustic matching sheet formed from the composition; an acoustic wave probe; an acoustic wave measuring apparatus; a method for manufacturing an acoustic wave probe; and a material set, for an acoustic matching layer, that is suitable for preparation of the composition, in which the resin composition for an acoustic matching layer includes a binder including a resin; and metal particles having a monodispersity of 40% to 80%, wherein the monodispersity is calculated by equation (1):
monodispersity (%)=(standard deviation of particle sizes of metal particles/average particle size of metal particles)×100.

Disclosed herein is an aqueous coating composition containing an aqueous epoxy resin dispersion, an aqueous amine-functional resin dispersion and an aromatic carboxylic acid. The aqueous dispersion contains at least one specific di- and/or polyfunctional monomeric amine and at least one resin component including at least one specific polyfunctional organic amine. Further disclosed herein is a kit-of-parts including a base varnish containing the aqueous epoxy resin dispersion and a curing component containing the aqueous amine-functional resin dispersion as well as the aromatic carboxylic acid. Additionally disclosed herein is a process for producing a coating on the substrate as well as coated substrates resulting from said process. Cured coating layers formed from said compositions exhibit a good adhesion to the substrate as well as a high intercoat adhesion and blistering stability under humidity conditions without negatively influencing the excellent sandability and the good stone chipping properties.

The present disclosure provides a resin composition for a metal substrate, and a resin varnish and a metal base copper-clad laminate comprising the same. The resin composition comprises 5-40% of a main resin and 60-95% of a thermally conductive filler when the total weight of the resin composition is calculated as 100%, wherein the main resin comprises 60-90% of a flexible epoxy resin having a structure as shown in Formula I and 10-40% of a phenoxy resin when the total weight of the main resin is calculated as 100%. The resin composition provided by the present disclosure has a low modulus, can alleviate the stress generated by thermal shocks and can withstand more than 1000 thermal cycles.

There are provided an aromatic amine resin represented by the following formula (1) wherein a plurality of R.sub.1's each independently represent a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, provided that a case where all R.sub.1's represent each a hydrogen atom is excluded, m represents an integer of 1 to 4, n represents an integer, and the average value (A) of n represents: 1≦A≦5, which can be utilized for a high-reliability semiconductor, a high-performance fiber-reinforced composite material, and others; an epoxy resin composition containing the aromatic amine resin; and an epoxy resin cured product having properties excellent in high heat resistance and low hygroscopicity, which is obtained by curing the epoxy resin composition.

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