Epoxy resin composition, prepreg, and fiber reinforced composite material

Patent metadata

Field	Value
Publication number	US-10344117-B2
Application number	US-201515549527-A
Country	US
Kind code	B2
Filing date	Nov 27, 2015
Priority date	Feb 9, 2015
Publication date	Jul 9, 2019
Grant date	Jul 9, 2019

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.

First claim

The invention claimed is:

1. An epoxy resin composition comprising:
100 parts by mass of [A] an epoxy resin;
[B] dicyandiamide, present in an amount such that 0.3 to 1.2 equivalents of active hydrogen groups of [B] are present per equivalent of epoxy groups in the epoxy resin composition;
1 to 8 parts by mass of [C] aromatic urea; and
0.1 to 8 parts by mass of [D] a boric ester;
wherein the epoxy resin composition fulfills condition (i) and at least one of conditions (ii) and (iii) given below:
(i) to meet requirement [a] and requirement [b],
(ii) to meet requirement [c] and requirement [d], and
(iii) to meet requirements [c] and requirements [e],
where requirements [a] to [e] are as follows:
[a]: a time period after reaching 100° C. until reaching a peak top in a heat flow curve is 60 minutes or shorter when the epoxy resin composition is analyzed in a nitrogen stream at a constant temperature of 100° C. using a differential scanning calorimeter,
[b]: a time period after reaching 60° C. until reaching a peak top in a heat flow curve is 25 hours or longer when the epoxy resin composition is analyzed in a nitrogen stream at a constant temperature of 60° C. using a differential scanning calorimeter,
[c]: an average epoxy equivalent over all epoxy resins is 165 g/eq or more and 265 g/eq or less,
[d]: [A] contains 10 to 50 parts by mass of an epoxy resin [A1] that is represented by formula (I) and/or formula (II):

wherein R 1 , R 2 , and R 3 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]: [A] contains 10 to 50 parts by mass of a tri- or higher functional glycidyl amine type epoxy resin [A2].

2. An epoxy resin composition as set forth in claim 1 , wherein conditions (i), (ii), and (iii) are fulfilled.

3. An epoxy resin composition as set forth in claim 1 , wherein [A] further contains 20 to 90 parts by mass of a bisphenol F type epoxy resin [A3].

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

5. An epoxy resin composition as set forth in claim 1 , wherein at least conditions (i) and (ii) are fulfilled, and [A1] is represented by formula (II).

6. An epoxy resin composition as set forth in claim 1 , wherein [C] contains toluene bis-dimethylurea.

7. A prepreg comprising the epoxy resin composition as set forth in claim 1 and carbon fiber.

8. A fiber reinforced composite material produced by curing the prepreg as set forth in claim 7 .

Assignees

• Toray Industries

Inventors

• Sano Kentaro
• Takaiwa Reo
• Hirano Noriyuki

Classifications

• C08K7/06

  Elements · CPC title

• C08G59/4021 Primary

  Ureas; Thioureas; Guanidines; Dicyandiamides · CPC title

• C08L63/00

  Compositions of epoxy resins; Compositions of derivatives of epoxy resins · CPC title

• C08G59/02

  Polycondensates containing more than one epoxy group per molecule · CPC title

• C08J2363/00

  Characterised by the use of epoxy resins; Derivatives of epoxy resins · CPC title