An epoxy resin composition includes [A] an epoxy resin, [B] dicyandiamide, [C] an aromatic urea and [D] a boric acid ester and satisfies any one of (i) requirements [a] and [b], (ii) requirements [c] and [d] and (iii) requirements [c] and [e]:[a]: the time from when the temperature reaches 100 C. till when the heat flow reaches a peak top is 60 minutes or shorter as determined by a differential scanning calorimetry; [b]: the time from when the temperature reaches 60 C. till when the heat flow reaches a peak top is 25 hours or longer as determined by a differential scanning calorimetry; [c]: the average in all of the epoxy resins is 165 to 265 g/eq inclusive; [d]: in the component [A], [A1] a resin represented by formula (I) and/or a resin represented by formula (II) is contained in an amount of 10 to 50 parts by mass relative to the total amount of all of the epoxy resins; and [e]: in the component [A], [A2] a glycidylamine-type resin having a functionality of 3 or higher is contained in an amount of 10 to 50 parts by mass relative to the total amount of all of the epoxy resins.

Provided are an epoxy resin including: an epoxidized product of monoalkyl dihydroxybenzene; and a compound that is detected in the molecular weight range from a molecular weight at the peak top of the epoxidized product of the monoalkyl dihydroxybenzene to the molecular weight at the peak top+20 to 40 and has a peak area % of 0.1% to 0.8% in a GPC chart, and an epoxy resin including an epoxidized product of monoalkyl catechol in which the ratio of the total content of a cyclic compound having a cyclic structure that has two adjacent oxygen atoms derived from the monoalkyl catechol as constituent atoms and a monoglycidyletherified product of the monoalkyl catechol to the content of a diglycidyletherified product of the monoalkyl catechol is in the range of 0.10 to 0.40 as measured by high performance liquid chromatography.

Provided is a thermosetting resin composition (C) of which curing can be started at a relatively low temperature in a short time and a cured product exhibits high heat resistance, the thermosetting resin composition (C) comprising an epoxy resin; an epoxy resin curing agent; and an epoxy resin curing accelerator, wherein the epoxy resin curing agent contains an imidazole-based curing agent 1 which is not encapsulated in a microcapsule and a curing agent 2 which is encapsulated in a microcapsule, and the epoxy resin curing accelerator comprises a urea derivative.

A two-component curable epoxy resin system having an epoxy component containing a unique combination of two or more epoxy resins with at least one of the epoxy resins being an epoxy novolac type resin. The composite made from such resin system exhibits high glass transition temperature.

Binder compositions that are formaldehyde free and include a latex emulsion, an epoxysilane, an epoxy dispersion, a polyol or a latex emulsion, a styrenic copolymer having carboxylic acid functionality, an epoxysilane or an epoxy dispersion or a mixture of both, a polyol and, optionally, an additive, wherein the composition does not comprise formaldehyde are described.

The present disclosure relates to a method for stably dispersing nanoparticles of a material in a curable polymer, the method comprising: a) providing a curable pre-polymer; b) providing particles of the material; and c) compounding the curable pre-polymer and the particles at a compounding temperature sufficiently high to obtain a curable melt mixture and sufficiently low for the curable melt mixture to develop a pre-determined viscosity upon compounding. The compounding is performed by applying a shear force to the heated curable melt mixture, whereby nanoparticles are formed from the particles, the viscosity of the melt being such that the nanoparticles remain dispersed in the mixture.

Provided are a curable resin composition, a dry film, a cured product, and an electronic component including the same that have excellent resolution, higher insulation reliability, and excellent embeddability in a circuit. A curable resin composition includes: (A) a carboxyl group-containing resin; (B) a photopolymerization initiator; (C) a thermosetting resin; and (D) silica, wherein a blending amount of (D) the silica is 10 to 60% by mass relative to a total solid content of the curable resin composition, (D) the silica includes (D-1) nanosilica, (D-1) the nanosilica has an average secondary particle size of 200 nm or less, and a degree of association of (D-1) the nanosilica is 2.3 or less.

Provided are: an epoxy resin composition for fiber-reinforced composite materials, which has a good balance between storage stability and fast curing properties at high levels; a prepreg; and an epoxy resin composition which exhibits excellent mechanical characteristics as a fiber-reinforced composite material. A resin composition which contains an epoxy resin, dicyandiamide, an imidazole compound and an acidic compound, while satisfying the following conditions (a)-(c): (d) The time until the heat flow rate reaches the peak top after the epoxy resin composition reaches 100 C. is 25 minutes or less as measured by a differential scanning calorimeter at an isothermal temperature of 100 C. in a nitrogen gas stream. (e) The time until the heat flow rate reaches the peak top after the epoxy resin composition reaches 60 C. is 15 hours or more as measured by a differential scanning calorimeter at an isothermal temperature of 60 C. in a nitrogen gas stream. (f) The ratio of the number of epoxy groups to the number of imidazole rings in the epoxy resin composition is from 25 to 90 (inclusive).

A prepreg comprising at least one layer of carbon fibers and a curable thermosetting resin system, the curable thermosetting resin system at least partly impregnating the at least one layer of carbon fibers, wherein the curable thermosetting resin system comprises: a. a curable thermosetting resin including at least one epoxide group; b. a curing agent for curing the curable thermosetting resin, wherein the curing agent is present in the liquid phase and includes a cyanamide reactive group; c. an accelerator for accelerating the curing of the thermosetting resin by the curing agent, wherein the accelerator includes at least one urea reactive group; and d. a rheology modifier for the curable thermosetting resin system, wherein the rheology modifier is at least one of a thermoplastic resin and an inorganic particulate thickener or a mixture thereof.

Methods for making and curing resin-based adhesives are disclosed using encapsulated amine accelerators activated by providing ultrasonic energy.