Provided are an epoxy resin composition including hexagonal boron nitride particles having an aspect ratio of 2 or more, a liquid crystalline epoxy monomer, and a curing agent, and the epoxy resin composition being capable of forming a resin matrix having a smectic domain by reacting the liquid crystalline epoxy monomer with the curing agent, and a thermally-conductive material precursor, a B-stage sheet, a prepreg, a heat dissipation material, a laminate, a metal substrate, and a printed circuit board, which use the epoxy resin composition.

Provided are an epoxy resin composition including hexagonal boron nitride particles having an aspect ratio of 2 or more, a liquid crystalline epoxy monomer, and a curing agent, and the epoxy resin composition being capable of forming a resin matrix having a smectic domain by reacting the liquid crystalline epoxy monomer with the curing agent, and a thermally-conductive material precursor, a B-stage sheet, a prepreg, a heat dissipation material, a laminate, a metal substrate, and a printed circuit board, which use the epoxy resin composition.

A release agent is disclosed for use with an organic binder system used in metal casting. The binder system has a Part I component including an epoxy resin and a free radical initiator and a Part II component having an epoxy resin and an acrylate, where the Part I and Part II components are kept separate until the time of use. The release agent will typically have a molecular weight in the range of 150 to 160, with eight to ten carbon atoms. Two examples of the epoxide are pinene oxide and decene-1 oxide, each of which is effective as an internal release agent when present in the binder for a cold box process in the range of about 0.15% to about 1% of the total weight of the Part I and Part II components.

An epoxy resin composition comprises components [A] to [C]. The component [C] is a component [c1] or [c2] and the rubbery state elastic modulus of a cured article produced by curing the epoxy resin composition in a dynamic viscoelasticity evaluation is 10 MPa or less. Component[A] is a phenyl glycidyl ether substituted by a tert-butyl group, a sec-butyl group, an isopropyl group or a phenyl group. Component [B] is a bifunctional or higher aromatic epoxy resin. Component [C] is a curing agent selected from component [c1], which is an acid anhydride-type curing agent and component [c2], which is an aliphatic amine-type curing agent.

The present invention is a negative-acting photosensitive resin composition including (A) a compound having a triazine ring and represented by formula (1) (in formula (1), each R.sub.1 independently represents an organic group, wherein at least one R.sub.1 represents an organic group having a glycidyl group or an organic group having an oxetanyl group), (B) an epoxy resin having in each molecule a benzene backbone and at least two epoxy groups and having an epoxy equivalent weight of not more than 500 g/eq., and (C) a cationic photopolymerization initiator. The content of the (A) compound represented by formula (1) with reference to the (B) epoxy resin is 1 to 50 mass %. The (B) epoxy resin satisfies at least one of the following conditions (i) and (ii): condition (i) a weight-average molecular weight of at least 500, and condition (ii) a softening point of at least 40° C.

##STR00001##

A resin sheet includes an epoxy resin including an epoxy resin oligomer and an epoxy resin monomer; a curing agent; and an inorganic filler, wherein a content of the inorganic filler is more than 30% by volume but less than 80% by volume.

The present invention discloses a monoepoxy compound represented by the following Formula (1), a curable composition containing the same, a cured product therefrom, a method of producing the monoepoxy compound, and a reactive diluent containing the monoepoxy compound. The monoepoxy compound represented by the Formula (1) is useful in that it is capable of reducing the viscosity of a curable composition containing the monoepoxy compound, while preventing a reduction in the heat resistance of the curable composition as well as a reduction in the weight of the curable composition upon curing. ##STR00001##
(In the Formula (1), R.sup.1 to R.sup.6 are each independently selected from the group consisting of a hydrogen atom, an alkyl group, and an alkoxy group.)

The present invention discloses a monoepoxy compound represented by the following Formula (1), a curable composition containing the same, a cured product therefrom, a method of producing the monoepoxy compound, and a reactive diluent containing the monoepoxy compound. The monoepoxy compound represented by the Formula (1) is useful in that it is capable of reducing the viscosity of a curable composition containing the monoepoxy compound, while preventing a reduction in the heat resistance of the curable composition as well as a reduction in the weight of the curable composition upon curing. ##STR00001##
(In the Formula (1), R.sup.1 to R.sup.6 are each independently selected from the group consisting of a hydrogen atom, an alkyl group, and an alkoxy group.)

A photosensitive composition contains a polysiloxane compound, a photoacid generator, a coloring agent and a solvent. A content of the coloring agent with respect to a total solid content of the composition is 5% by weight or more. The polysiloxane compound contains a cyclic polysiloxane structure and a cationically polymerizable functional group. The polysiloxane compound may further have an alkali-soluble functional group. A content of the polysiloxane compound with respect to the total solid content of the composition is preferably 20-80% by weight. The photosensitive composition is used, for example, in formation of a colored pattern.

A photosensitive composition contains a polysiloxane compound, a photoacid generator, a coloring agent and a solvent. A content of the coloring agent with respect to a total solid content of the composition is 5% by weight or more. The polysiloxane compound contains a cyclic polysiloxane structure and a cationically polymerizable functional group. The polysiloxane compound may further have an alkali-soluble functional group. A content of the polysiloxane compound with respect to the total solid content of the composition is preferably 20-80% by weight. The photosensitive composition is used, for example, in formation of a colored pattern.