# US 2018/0022862 A1 · Epoxy resin composition, prepreg, and fiber reinforced composite material

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- Number: US 2018/0022862 A1
- Document ID: US20180022862A1
- Status: Published application
- Kind: A1
- Application number: 15/549,527
- Filed: 2015-11-27
- Published: 2018-01-25
- Earliest claimed: 2015-02-09
- Assignees: Toray Industries, Inc.
- Applicants: Toray Industries, Inc.
- Inventors: Kentaro Sano; Reo Takaiwa; Noriyuki Hirano
- Web page: https://patentgrep.com/patent/US20180022862A1

## CPC

- C08G 59/4021: {Ureas; Thioureas; Guanidines; Dicyandiamides}
- C08G 59/02: Polycondensates containing more than one epoxy group per molecule
- C08J 5/243: {using carbon fibres}
- C08J 5/249: {characterised by the additives used in the prepolymer mixture}
- C08K 7/06: Elements
- C08L 63/00: Compositions of epoxy resins; Compositions of derivatives of epoxy resins
- C08J 2363/00: Characterised by the use of epoxy resins; Derivatives of epoxy resins
- C08J 2363/04: Epoxynovolacs
- C08G: MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08J: WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H (working, e.g. shaping, of plastics B29)
- C08K: Use of inorganic or non-macromolecular organic substances as compounding ingredients (paints, inks, varnishes, dyes, polishes, adhesives C09)
- C08L: COMPOSITIONS OF MACROMOLECULAR COMPOUNDS (compositions based on polymerisable monomers C08F, C08G; artificial filaments or fibres D01F; textile treating compositions D06)

## Abstract

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.

## Claims

### Claim 1

An epoxy resin composition comprising component [A], which is an epoxy resin, component [B], which is dicyandiamide, component [C], which is aromatic urea, and component [D], which is a boric ester, and fulfilling any of the conditions from (i) to (iii) given below:
(i) to meet requirement [a] and requirement [b],
(ii) to meet requirement [c] and requirement [d], and
(iii) to meet requirement [c] and requirement [e],
where requirements [a] to [e] are as follows:
[a]: the time period after reaching 100° C. until reaching the peak top in the heat flow curve is 60 minutes or shorter when an epoxy resin composition is analyzed in a nitrogen stream at a constant temperature of 100° C. using a differential scanning calorimeter,
[b]: the time period after reaching 60° C. until reaching the peak top in the heat flow curve is 25 hours or longer when an epoxy resin composition is analyzed in a nitrogen stream at a constant temperature of 60° C. using a differential scanning calorimeter,
[c]: the average epoxy equivalent over all epoxy resins is 165 g/eq or more and 265 g/eq or less,
[d]: component [A] contains an epoxy resin [A1] that is represented by formula (I) and/or formula (II) and accounts for 10 parts by mass to 50 parts by mass of the total epoxy resin quantity, which represents 100 parts by mass:
wherein R1, R2, and R3 each are a hydrogen atom or a methyl group, and n is an integer of 1 or greater,
wherein n is an integer of 1 or greater, and
[e]: component [A] contains a tri- or higher functional glycidyl amine type epoxy resin [A2] that accounts for 10 parts by mass to 50 parts by mass of the total epoxy resin quantity, which represents 100 parts by mass.

### Claim 2 (depends on 1)

An epoxy resin composition as set forth in claim 1, wherein condition (i) is fulfilled and component [A] contains a tri- or higher polyfunctional epoxy resin.

### Claim 3 (depends on 1)

An epoxy resin composition as set forth in either claim 1, wherein condition (i) is fulfilled and requirement [d] is met.

### Claim 4 (depends on 1)

An epoxy resin composition as set forth in claim 1, wherein requirement [d] is met and the epoxy groups in the epoxy resin [A1] that is represented by formula (I) and/or formula (II) contain 3.0 or more functional groups on average per molecule.

### Claim 5 (depends on 1)

An epoxy resin composition as set forth in claim 1, wherein either condition (i) or (ii) is fulfilled and requirement [e] is met.

### Claim 6 (depends on 1)

An epoxy resin composition as set forth in claim 1, wherein component [A] contains bisphenol F type epoxy resin [A3] that accounts for 20 parts by mass to 90 parts by mass of the total epoxy resin quantity, which represents 100 parts by mass.

### Claim 7 (depends on 1)

An epoxy resin composition as set forth in claim 1 that, when cured by heating at 130° C. for 2 hours, gives cured resin having a bending elastic modulus of 3.5 GPa or more.

### Claim 8 (depends on 1)

Prepreg comprising an epoxy resin composition as set forth in claim 1 and carbon fiber.

### Claim 9 (depends on 8)

Fiber reinforced composite material produced by curing prepreg as set forth in claim 8.