Provided are a thermosetting epoxy resin composition and a prepreg, laminated board and printed circuit board using the thermosetting epoxy resin composition. The thermosetting epoxy resin composition comprises the following components in parts by weight: 2-10 parts of a phosphorus-containing anhydride, 5-40 parts of a phosphorus-free anhydride, 5-45 parts of an epoxy resin, 40-70 parts of a filler, and 0-15 parts of a phosphorus-containing flame retardant, with the total part by weight of all these components being 100 parts, wherein the phosphorus-containing anhydride has a structure as represented by formula I or II, and the epoxy resin is selected from one of or a combination of at least two of a bisphenol A epoxy resin, a bisphenol F epoxy resin and a biphenyl epoxy resin. The thermosetting epoxy resin composition also has good heat resistance, discoloration resistance and dimensional stability after curing while ensuring V-0 grade flame resistance, and can be used for the preparation of printed circuit board substrates in the field of LEDs.

The present invention provides a thermally conductive material having excellent thermal conductivity. Furthermore, the present invention provides a device with a thermally conductive layer that has a thermally conductive layer containing the thermally conductive material and a composition for forming a thermally conductive material that is used for forming the thermally conductive material. The thermally conductive material according to an embodiment of the present invention contains a cured substance of a disk-like compound, which has one or more reactive functional groups selected from the group consisting of a hydroxyl group, a carboxylic acid group, a carboxylic acid anhydride group, an amino group, a cyanate ester group, and a thiol group, and a crosslinking compound which has a group reacting with the reactive functional groups.

To provide an epoxy resin composition capable of forming a polished surface with high flatness when polished after curing, and a method for producing an electronic component mounting structure having a polished surface with high flatness, the polished surface obtained by polishing the surface of an encapsulation body. Disclosed are an epoxy resin composition, an electronic component mounting structure including the epoxy resin composition, and a method for producing the electronic component mounting structure, wherein: the epoxy resin composition includes a fused silica possibly containing hollow particles, and a curing agent; on a polished surface obtained by polishing a cured product of the epoxy resin composition, the number of pores having a diameter of more than 5 μm observed within a 25-mm.sup.2 area is one or less, the pores derived from cross sections of the hollow particles; and the polished surface is coated with a coating material.

Provided is a sheet-like prepreg that has both a low coefficient of linear thermal expansion and high flexibility and offers excellent anti-warpage performance and cracking resistance. The sheet-like prepreg according to the present invention includes a curable composition and a sheet-like porous support impregnated with the curable composition. The sheet-like porous support is made from a material having a coefficient of linear thermal expansion of 10 ppm/K or less. The sheet-like prepreg gives a cured product having a glass transition temperature of −60° C. to 100° C. The curable composition includes one or more curable compounds (A) and at least one of a curing agent (B) and a curing catalyst (C). The curable compounds (A) include an epoxide having a weight per epoxy equivalent of 140 to 3000 g/eq in an amount of 50 weight percent or more of the totality of the curable compounds (A).

Provided are a white heat-curable epoxy resin composition capable of yielding a cured product that is tough and superior in initial reflection rate and heat resistance; and a semiconductor device with a light receiving element and other semiconductor elements being encapsulated by such cured product. The white heat-curable epoxy resin composition contains: (A) a prepolymer as a molten mixture of (A-1) an epoxy resin: a triazine derivative epoxy resin and/or an alicyclic epoxy compound having an epoxy group and an alicyclic structure in one molecule and being non-fluid at 25° C., (A-2) an acid anhydride having no carbon-carbon double bond and (A-3) an acrylic resin-based modifier having an epoxy group and a weight-average molecular weight of 1,000 to 30,000; (B) a white pigment containing a titanium oxide; (C) an inorganic filler; (D) a curing accelerator; and (E) an antioxidant.

The invention relates to a composition comprising components a), b) and c), to a process for the preparation thereof, and to the use thereof. In one embodiment, a composition is provided which comprises the following components a), b) and c): a) from 75 to 99.5% by weight of a polymer based on epoxide compounds, from 0.5 to 25% by weight of at least one polyhydric alcohol, and optionally additives, b) from 80 to 99% by weight of a curing agent which is suitable for curing the polymer based on epoxide compounds, from 1 to 20% by weight of a polycaprolactone-polysiloxane block copolymer, optionally an accelerator, and optionally additives, and c) optionally an accelerator.

Provided is a curable epoxy composition capable of forming a cured product having excellent heat resistance even in a high temperature environment. A first curable epoxy composition includes an alicyclic epoxy compound (A) having an alicyclic structure and an epoxy group in a molecule, an acid anhydride-based curing agent (B), and an imidazole-based curing accelerator (C), and is liquid at 25° C. and to be used for a rotary electric machine. A second curable epoxy composition includes an alicyclic epoxy compound (A) having an alicyclic structure and an epoxy group in a molecule, an acid anhydride-based curing agent (B), an imidazole-based curing accelerator (C), and a polyester polyol (D), and is to be used for a rotary electric machine.

Embodiments include curable compositions including an epoxy resin and a hardener component including a polymer having first constitutional unit, a second constitutional unit, and a third constitutional unit, where the epoxy group to the second constitutional unit has a molar ratio in a range of 0.5:1 to 5:1. Embodiments include prepregs that include a reinforcement component and the curable composition and an electrical laminate formed with the curable composition.

Provided is an encapsulation method not causing molding failures such as filling failures and flow marks when collectively encapsulating a large-area silicon wafer or substrate with a resin composition. Specifically, provided is a method for encapsulating a semiconductor element-mounted base material, using a curable epoxy resin composition containing: an epoxy resin (A), a curing agent (B), a pre-gelatinizing agent (C) and a filler (D). The semiconductor element-mounted base material is collectively encapsulated under conditions of (a) molding method: compression molding, (b) molding temperature: 100 to 175° C., (c) molding period: 2 to 20 min and (d) molding pressure: 50 to 350 kN.

The present invention relates to a halogen-free epoxy resin composition, a prepreg, a laminate and a printed circuit board containing the same. The halogen-free epoxy resin composition comprises an epoxy resin and a curing agent. Taking the total equivalent amount of the epoxy groups in the epoxy resin as 1, the active groups in the curing agent which react with the epoxy groups have an equivalent amount of 0.5-0.95. By controlling the equivalent ratio of the epoxy groups in the epoxy resin to the active groups in the curing agent to be 0.5-0.95, the present invention ensures the Df value stability of prepregs under different curing temperature conditions while maintaining a low dielectric constant and a low dielectric loss. The prepregs and laminates prepared from the resin composition have comprehensive performances, such as low dielectric constant, low dielectric loss, excellent flame retardancy, heat resistance, cohesiveness, low water absorption and moisture resistance, and are suitable for use in halogen-free multilayer circuit boards.