An object of the present invention is to provide an epoxy resin composition that can be preferably used for prepreg and fiber reinforced composite material applications and is excellent in elastic modulus, strength, and pot life.

The present invention is the epoxy resin composition including the following components [A] to [C] and satisfying the following conditions (1) to (3): [A]: epoxy resin [B]: polyamine curing agent, and [C]: a compound having a boiling point of 130° C. or more and a molecular weight m of 50 or more and 250 or less, the compound having no epoxy group in the molecule and having substantially no curing ability of an epoxy resin, and (1): at least a part of the component [C] has two or more alcoholic hydroxyl groups in the molecule. (2): the ratio C/E of the amount by mole, E, for epoxy groups of the component [A] to the amount by mole, C, of the component [C] satisfying the condition (1) is 0.01 or more and 0.20 or less. (3): the viscosity at 70° C. for 2 hours is 5.0 times or less the initial viscosity at 70° C.

An object of the present invention is to provide a fiber-reinforced composite material achieving both lightweight properties and mechanical properties, a laminate thereof, and a prepreg capable of easily molding a sandwich structure thereof. The present invention is a prepreg comprising a reinforced fiber substrate (B) impregnated with a resin (A), wherein the reinforced fiber substrate (B) exists in a folded state having a plurality of folds with a fold angle of 0° or more and less than 90° in the prepreg.

The present disclosure relates to a prepreg, a preparation method thereof and a fiber-reinforced composite material prepared therefrom. The preparation method of a prepreg may include an aramid fiber base material with improved wettability to resin, can increase a thickness reduction rate during molding of the prepreg, has an appropriate resin content, and can provide a prepreg suitable for molding by an out-of-autoclave process. In addition, the prepreg may provide a fiber-reinforced composite material that exhibits a thin thickness and a high resin content even by an out-of-autoclave process, and shows high strength and low moisture absorption

An epoxy resin mixture which contains an epoxy resin represented by Formula (1) below and an epoxy resin represented by Formula (2) below at a weight ratio of 1:5 to 1:0.2. (In Formula (1), plural R1's each exist independently and represent a hydrogen atom or a C1-10 alkyl group, n represent a real number of 1 to 10, and G represents a substituted or unsubstituted glycidyl group.) (In Formula (2), plural R2's and R3's each exist independently and represent a hydrogen atom or a C1-10 alkyl group, n represents a real number of 1 to 10, and G represents a substituted or unsubstituted glycidyl group.)

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The present teachings contemplate a method that includes a step of providing a first amount of esterified reaction product of an acid and an epoxy-based material. The esterified reaction product may be further reacted an epoxy resin to form a polymeric epoxy. The resulting material may have a generally linear backbone, foaming and curing capability and flame retardant properties.

The invention relates to an aqueous resin dispersion D comprising a mixture of a hydrophilically modified epoxy-based resin P and a resole R, and a co-crosslinker E, to a process for the preparation of the aqueous resin dispersion D, and to a method of use thereof to prepare coating films to prevent corrosion of the coated substrate.

The invention relates to a hydrogel based on water, on hydrosoluble monomeric or polymeric isosorbide epoxide and on hydrosoluble amine, to the method for preparing same and to the use thereof.

The present invention provides a fiber-reinforced-resin composite molded article including: a rigid layer that is formed of a fiber-reinforced-resin material for a rigid layer; a shaping layer that is formed, at least on one side of the rigid layer, of a shaping-layer compound composed of a thermosetting resin and fibers that are shorter than fibers contained in the fiber-reinforced-resin material for a rigid layer; and a cured resin being formed of a liquid-state resin that is deposited on the surface of the shaping layer. The fiber-reinforced-resin composite molded article has a structure in which the fiber-reinforced-resin material for a rigid layer, the shaping-layer compound, and the liquid-state resin are cured under heat and pressure in a layered state.

The present invention provides a polyfunctional phenolic resin and a polyfunctional epoxy resin having low viscosity and having excellent mechanical properties and heat resistance of a cured product to be obtained, a curable resin composition containing these, and a cured product thereof. Specifically, provided are a polyfunctional phenolic resin formed with a naphthol structure optionally having a substituent on an aromatic ring and a catechol structure optionally having a methyl group as a substituent on an aromatic ring bonded together via a methylene group optionally having a substituent, a polyfunctional epoxy resin obtained by epoxidizing the polyfunctional phenolic resin, a curable resin composition containing any of these, and a cured product thereof.

A method of reducing foamed density that results in a foamed polyvinyl chloride (PVC) component exhibiting reduced density. The foamed PVC component contains at least a PVC resin and a process aid blend. The process aid blend contains from 1 weight % to 60 weight % (based on the weight of the blend) of a functionalized process aid, and from 99 weight % to 40 weight % (based on the weight of the blend) of a non-functionalized process aid. The functionalized process aid includes at least one base polymer functionalized with a reactive epoxy, hydroxyl, β-keto ester, β-keto amide, or carboxylic acid functional group. The foamed PVC component containing the process aid blend has a lower density than a reference foamed PVC component made using the same process conditions and additives, but which contains only non-functionalized process aid and not the functionalized process aid.