Provided is an encapsulating resin composition that is used for collectively encapsulating a circuit board (10) and at least a part of a connector portion (20), in which the encapsulating resin composition contains a curing accelerator, the connector portion (20) includes a terminal (21) that electrically connects the circuit board (10) with the external device, and a housing (22) that is disposed on an outer periphery of the terminal (21) and is encapsulated by the encapsulating resin composition, the housing (22) contains a thermoplastic resin, and in a differential scanning calorimetry (DSC) curve of the encapsulating resin composition obtained in a case where a temperature is increased from 30° C. to 200° C. under conditions of a temperature increase rate of 10° C./min using a DSC meter, a maximum heat release peak temperature is equal to or higher than 100° C. and equal to or lower than 163° C., and a half-value width of a maximum heat release peak is equal to or higher than 5° C. and equal to or lower than 25° C.

An encapsulating material for compression molding includes an epoxy resin, a curing agent, and an inorganic filler. In an image obtained by observing, with an ultrasonic flaw detector, a compression-molded body formed by compression-molding the encapsulating material for compression molding on a substrate with a silicon chip interposed, the area of the portion other than dark spots of the region corresponding to the compression-molded body on the chip is 86% or more of the area of the entire region corresponding to the compression-molded body on the chip.

A flux resin composition includes an epoxy resin, an imidazole compound, a thixo agent, and an activator. The epoxy resin includes at least one resin selected from the group consisting of naphthalene epoxy resins, biphenyl aralkyl epoxy resins, trisphenol methane epoxy resins, biphenyl epoxy resins, and dicyclopentadiene epoxy resins. The content of the at least one resin is equal to or greater than 20% by weight with respect to a total weight of the epoxy resin.

An epoxy resin represented by the following formula (1), in which in a total amount of an epoxy compound represented by n=1 in the epoxy resin of the above formula, a total content of an epoxy compound represented by the following formula (2) and an epoxy compound represented by the following formula (3) is 1 area % or more and less than 70 area % in HPLC area percentage.

##STR00001##

The present disclosure relates to an epoxy resin of which distribution of molecular weight having distribution range of molecular weight of 300 to 2,000,000 is adjusted such that an upper limit value is increased to a maximum of 2,000,000, a method of preparing the same, a composition comprising the same, and a use thereof. The epoxy resin having controlled distribution of molecular weight of the present disclosure may have improved thermal properties of an epoxy system by expanding the distribution of molecular weight, and may exhibit excellent processability.

##STR00001##

The present invention relates to a resin composition, comprising (a) an epoxy resin; (b) a curing agent comprising the structure of formula C1; (c) an inorganic filler; wherein R.sup.C1 is (a) a siloxane group of formula C1a or (b) or both a siloxane group of formula C1a and an ester group of formula C1b; R.sup.C2 is selected from a bulky C.sub.4 to C.sub.12 alkyl group comprising at least one tertiary or quaternary carbon atom; R.sup.C11, R.sup.C12, R.sup.C13 are independently selected from methyl, ethyl and 1-propyl; R.sup.C14 is selected from a linear or branched C.sub.1 to C.sub.8 alkyl; X.sup.C1 is selected from a divalent C.sub.1 to C.sub.4 alkanediyl group; and n is an average number of repeating units and is from 1.05 to 200.

An epoxy resin composition suitable for molding a fiber-reinforced plastic molded article is provided. The molded article has exceptional mechanical properties. In particular, a tubular molded article has high breaking strength. The epoxy resin composition contains components (A), (C), and (D), where component (A) is an epoxy resin of a particular formula, component (C) is an epoxy resin other than component (A) that is liquid at 25° C., and component (D) is a curing agent.

Polyphenolic condensates and epoxidized products prepared from said condensates are prepared by a reaction utilizing multi catalysts to control the weight average molecular weight (Mw) and the number average molecular weight (Mn). Improved color and ultraviolet absorbance are possessed by the condensates described herein.

A curable epoxy composition comprising a polyvalent epoxy compound (A) having a biphenyl structure and/or condensed polycyclic structure, a trivalent or higher polyvalent phenol type epoxy compound (B), and a triazine structure-containing phenol resin (C) and a film, laminated film, prepreg, laminate, cured article, and composite article obtained using the same are provided.

Provided are an epoxy resin composition, which exhibits excellent low dielectric properties, and imparts excellent copper foil peel strength and interlayer cohesive strength when used in printed circuit plate applications; and a phenolic resin or an epoxy resin, which are for forming the epoxy resin composition. The phenolic resin is represented by General Formula (1) below.

##STR00001##

In the formula, R.sup.1's each represent a hydrocarbon group having 1 to 10 carbon atoms; R.sup.2's each represent a hydrogen atom, Formula (1a), or Formula (1b), where at least one of R.sup.2's is Formula (1a) or Formula (1b); and n represents the number of repetitions of 0 to 5.