Provided are a fiber-reinforced composite material excellent in heat resistance and strength properties, an epoxy resin composition to obtain the fiber-reinforced composite material, and a prepreg obtained by using the epoxy resin composition. Further provided are a fiber-reinforced composite material having less volatile matters during the curing time, and having excellent heat resistance and strength properties, an epoxy resin composition to obtain the fiber-reinforced composite material, and a prepreg obtained by using the epoxy resin composition. Provided are: an epoxy resin composition for a fiber-reinforced composite material, comprising an amine type epoxy resin [A], an aromatic amine curing agent [B], and a block copolymer [C] having a reactive group capable of reacting with an epoxy resin; a prepreg obtained by impregnating a reinforced fiber with the epoxy resin composition; and a fiber-reinforced composite material obtained by curing the prepreg. Further provided are: an epoxy resin composition comprising an epoxy resin [A] having two or more of four- or more-membered ring structures, and having either one of a glycidyl amino group directly bonded to the ring structure or a glycidyl ether group directly bonded to the ring structure, epoxy resin [B] having three or more of functional groups, a curing agent [C], and an elastomer component [D]; a prepreg obtained by impregnating a reinforced fiber with the epoxy resin composition; and a fiber-reinforced composite material obtained by curing the prepreg.

Epoxy resin composition for fiber-reinforced composite material, prepreg, and fiber-reinforced composite material

An epoxy resin composition comprising an epoxy resin [A], an amine-based curing agent [B] and a block copolymer [C] as components, wherein the epoxy resin [A] contains [Aa] an epoxy resin having at least one structure selected from a condensed polycyclic structure, biphenyl structure and oxazolidone ring structure; [Ab] an epoxy resin selected from a polyfunctional amine type epoxy resin [Ab1] and a liquid bisphenol type epoxy resin [Ab2], and the block copolymer [C] is at least one block copolymer selected from the group consisting of S-B-M, B-M and M-B-M. The present invention provides an epoxy resin composition that can be cured to form a cured product excellent in heat resistance, elastic modulus and toughness.

Epoxy resin composition, prepreg, and fiber-reinforced composite material

A prepreg giving a cured product exhibiting a lowered water adsorption comprising reinforcing fibers and a matrix resin comprising an epoxy resin of a specific composition, a curing agent of a specific structure, and a highly heat-resistant thermoplastic resin; a prepreg improved in interlaminar strength comprising reinforcing fibers and a matrix resin comprising an epoxy resin of a specific composition, a curing agent of a specific structure, and a highly heat-resistant thermoplastic resin; a prepreg improved in interlaminar strength and giving a cured product exhibiting a lowered water absorption, comprising reinforcing fibers and a matrix resin comprising an epoxy resin of a specific composition, a curing agent of a specific structure, and a highly heat-resistant thermoplastic resin; and a product prepared by curing the prepeg which is satisfactory in both impact resistance (residual compressive strength after impacting) and characteristics in a wet-heat atmosphere (compressive strength of perforated plate under the circumstances of high temperature and humidity), both properties having been conflicting with each other in the prior art.

Prepreg and fiber-reinforced composite material

A core crush resistant prepreg for use in making a fiber reinforced composite panel structure is provided. The prepreg comprises a woven fabric consisting essentially of carbon fiber tow strands impregnated with a hardenable polymeric resin composition. Typically the fabric has an areal weight of from about 180 to about 205 grams per square meter. The prepreg has an average fiber tow aspect ratio of less than about 15.4, a prepreg thickness of at least about 0.245 mm, and a prepreg openness of at least about 1.2 percent but less than about 6.0 percent. Preferably, the resin composition is predominantly viscous in nature and has a tan δ value of between 0.9 and 2.0 at an elevated temperature between 70° C. and 140° C., and an average epoxy functionality of greater than 2.0. A method for evaluating core crush resistance properties of a prepreg is also provided. The method includes determining a fiber tow average aspect ratio of the prepreg, determining a prepreg thickness, and comparing said average fiber tow aspect ratio and prepreg thickness to a set of predetermined values.

Core-crush resistant fabric and prepreg for fiber reinforced composite sandwich structures

An apparatus is described for withdrawing filtered permeate from a substrate contained in a reservoir at ambient pressure. The apparatus includes a plurality of membrane assemblies. Each assembly has a plurality of hollow fiber filtering membranes, immersed in the reservoir, at least one permeating header with the membranes sealingly secured therein, and a permeate collector to collect the permeate sealingly connected to the at least one permeating header and in fluid communication with lumens of the membranes. The membranes of each assembly extend generally vertically upwards from a first header during permeation. One or more sources of suction are provided in fluid communication with the lumens of the membranes of each assembly through the permeate collectors and apply sufficient suction to withdraw permeate from the lumens of the membranes. An aeration system for discharging bubbles assists in keeping the membranes clean. In other aspects, a method of removing fouling materials from the surface of a plurality of porous membranes includes providing, from within a membrane module, gas bubbles in a uniform distribution relative to the membranes. The bubbles move past the surfaces of the membranes to dislodge fouling materials from them. The membranes are arranged in close proximity to one another and mounted to prevent excessive movement.

Apparatus for withdrawing permeate using an immersed vertical skein of hollow fibre membranes

A woven fabric prepreg comprising at least [A] a woven fabric as reinforcing fibers, [B] a thermosetting resin or thermosetting resin composition and [C] fine particles of a resin and having a cover factor of 95% or more, and a honeycomb sandwich panel, comprising skin panels fabricated by said woven fabric prepreg and [D] a honeycomb core can be obtained. The woven fabric prepreg little changes in tackiness with the lapse of time and has moderate drapability, being excellent in self adhesiveness to the honeycomb core when used as skin panels of a honeycomb sandwich panel. Furthermore, the honeycomb sandwich panel obtained has a small porosity in the skin panels fabricated by the cured prepreg and has excellent surface smoothness with few pits and depressions on the surfaces of the skin panels.

Prepreg fabric and honeycomb sandwich panel

Resin compositions for fiber-reinforced composite materials characterized by comprising (A) epoxy resin, (B) hardener, and (C) additive as the essential ingredients and having a storage rigidity G' of 5 to 200 Pa throughout the whole temperature range of 70-100 °C when heated from 50 °C at a temperature rise rate of 1.5 °C/min by using plane parallel plates having an oscillation frequency of 0.5 Hz; and prepregs made by using the same. The prepregs are excellent in self-adhesion to honeycomb cores, give skin panels having a reduced porosity, an excellent surface smoothness, and appropriate tackiness and draping properties, thus being usable in aircrafts, automobiles, and industrial applications, especially as structural materials for aircrafts.

Resin compositions for fiber-reinforced composite materials and processes for producing the same, prepregs, fiber-reinforced composite materials, and honeycomb structures

A prepreg precursor including a carbon fiber woven fabric having applied to the fabric between about 0.5 to about 10 wt % of a stabilizer material for stabilizing the structural form of the fabric. Prepregs can then be produced using the woven fabric. Undesired settlement of matrix resin from the surface of the woven fabric is thus prevented. Hence, compared with a prepreg prepared using conventional woven fabric, a prepreg prepared by using the woven fabric of the invention can hold its tackiness for a long time and can be used to produce a fiber reinforced composite material excellent in smoothness without being devoid of surface resin.

Woven carbon fiber fabric

PROBLEM TO BE SOLVED: To strongly adhere a skin panel to a honeycomb core and to reduce a porosity in the panel very much by setting a woven fabric METSUKE of a reinforcing fiber woven fabric to a specific value range. SOLUTION: A skin panel is convenient in a production process preferably made of a prepreg or its laminate. In the honeycomb sandwich panel, reinforcing fiber woven fabric has a woven fabric METSUKE of 320 to 500 g/m2. If it is less than 320 g/m2, an exudation of a resin is deteriorated, and fillet formability is deteriorated, and surface smoothness of the panel might be lowered. If it exceeds 500 g/m2, resin impregnability of the resin when the prepreg is manufactured might be lowered. The reinforcing fabric having such a range of the METSUKE is preferable due to contribution to enhance a reducing effect of the manufacturing cost and the efficiency in the manufacturing steps.

Honeycomb sandwich panel

PURPOSE:To prevent precipitation of a matrix resin of a surface layer into a carbon fiber fabric to keep tackiness as a prepreg for a long time by a method wherein a form stabilizer is loaded by a predetermined percentage by weight per the total weight of the fiber material of the fabric. CONSTITUTION:A form stabilizer is loaded to a carbon fiber fabric in the amount of 0.5-10wt.% per the total weight of the fiber material of the fabric. After that, the carbon fiber fabric is impregnated with an epoxy resin composition to be formed as required prepreg. Alternatively, while or after a carbon fiber fabric loaded with a low-temperature curing agent for an epoxy resin is impregnated with an epoxy resin composition, a part of the epoxy resin composition is cured by the curing agent to be formed as a required prepreg. As the carbon fiber fabric used in this case, a two--dimensional fabric obtained by weaving a carbon fiber roving is used.

Masahiko Hayashi

Papers

Prepreg fabric and honeycomb sandwich panel

Resin compositions for fiber-reinforced composite materials and processes for producing the same, prepregs, fiber-reinforced composite materials, and honeycomb structures

Woven carbon fiber fabric

Honeycomb sandwich panel

Carbon fiber fabric, prepreg, fiber-reinforced composite material, and production thereof