EPOXY resin composition, prepreg and fiber-reinforced composite materials

Patent metadata

Field	Value
Publication number	US-9738782-B2
Application number	US-201113823004-A
Country	US
Kind code	B2
Filing date	Sep 26, 2011
Priority date	Sep 28, 2010
Publication date	Aug 22, 2017
Grant date	Aug 22, 2017

Abstract

An epoxy resin composition containing an epoxy resin [A1], epoxy resin [B1], epoxy resin [C1] and curing agent [D] wherein [A1] is a bisphenol-type epoxy resin with a softening point of 90° C. or more, [B1] is a tri- or higher functional amine-type epoxy resin, [C1] is a bisphenol F-type epoxy resin with a number average molecular weight of 450 or less, and the epoxy resins [A1] to [C1] satisfy the following contents per 100 parts by mass of total epoxy resin content: [A1] 20 to 50 parts by mass, [B1] 30 to 50 parts by mass and [C1] 10 to 40 parts. The present invention provides low-viscosity epoxy resin compositions that are excellent in impregnating reinforcing fibers and capable of producing cured resins with excellent modulus and toughness, as well as prepregs and fiber-reinforced composite materials based on those epoxy resin compositions.

First claim

The invention claimed is:

1. An epoxy resin composition containing an epoxy resin [A1], epoxy resin [B1], epoxy resin [C1] and curing agent [D],
wherein [A1] is a bisphenol F-type epoxy resin with a softening point of 108° C. to 135° C., [B1] is a tri- or higher functional amine-type epoxy resin, [C1] is a bisphenol F-type epoxy resin with a number average molecular weight of 450 or less,
wherein the epoxy resins [A1] to [C1] satisfy the following contents per 100 parts by mass of total epoxy resin content: [A1] 30 to 50 parts by mass, [B1] 30 to 50 parts by mass and [C1] 10 to 40 parts by mass, and
wherein a cured resin obtained by curing the epoxy resin composition has a phase separation structure involving an [A1]-rich phase and a [B1]-rich phase with a phase separation structural period of 1 nm to 5 μm.

2. An epoxy resin composition containing an epoxy resin [A2], epoxy resin [B2], epoxy resin [C2] and curing agent [D];
wherein [A2] is a bisphenol F-type epoxy resin with a softening point of 108° C. to 135° C.,
[B2] is a tri- or higher functional amine-type epoxy resin,
[C2] is a bisphenol F-type epoxy resin with a number average molecular weight of 450 or less, and
the epoxy resins [A2] to [C2] satisfy the following contents per 100 parts by mass of total epoxy resin content: [A2] 30 to 50 parts by mass, [B2] 30 to 50 parts by mass and [C2] 10 to 40 parts by mass,
and satisfies the conditions (1) to (4) below:
(1) The SP value of the cured resin [B2′], obtained by having the epoxy resin [B2] react with the curing agent [D] and curing it, is larger than the SP value of each of the cured resin [A2′] and [C2′], obtained, respectively, by having the epoxy resin [A2] and [C2] react with the curing agent [D] and curing it, by at least 1.2;
(2) The softening point of the epoxy resin [A2] is 90° C. or more and the softening points of the epoxy resin [B2] and [C2] are both 50° C. or less;
(3) The modulus of the cured resin obtained by having an epoxy resin composition containing the epoxy resin [C2], dicyandiamide containing active hydrogen groups quantified at 0.9 equivalent relative to the epoxy groups contained in the epoxy resin [C2], and 2 parts by mass of 3-(3,4-dichlorophenyl)-1,1-dimethylurea per 100 parts by mass of the epoxy resin [C2] undergo a reaction at 130° C. for 90 minutes after raising its temperature from room temperature to 130° C. at a rate of 2.5° C./min is 3.5 GPa or more;
(4) The cured resin obtained by curing the epoxy resin composition has a phase separation structure involving an [A2]-rich phase and a [B2]-rich phase with a phase separation structural period of 1 nm to 1 μm.

3. An epoxy resin composition as described in claim 1 wherein the epoxy resin [B1] is a trifunctional aminophenol-type epoxy resin.

4. An epoxy resin composition as described in claim 1 wherein the curing agent [D] is dicyandiamide or a derivative thereof.

5. An epoxy resin composition as described in claim 1 further containing at least one block copolymer [E] having a structure selected from the group consisting of S-B-M, B-M and M-B-M in an amount of 1 to 10 parts by mass per 100 parts by mass of total epoxy resin content, wherein each of the blocks denoted by the letters S, B and M is connected to another directly by means of a covalent bond or via a chemical structure, block M comprising a homopolymer of polymethyl methacrylate or a copolymer containing at least 50 mass % of methyl methacrylate, block B being incompatible with block M and having a glass transition temperature of 20° C. or less, and block S being incompatible with blocks B and M and having a glass transition temperature higher than that of block B.

6. An epoxy resin composition as described in claim 5 wherein the block copolymer [E] is a block copolymer denoted as M-B-M and block M contains as a copolymerization component a monomer having a SP value higher than that of methyl methacrylate.

7. An epoxy resin composition as described in claim 5 wherein block B of the block copolymer [E] is poly(1,4-butadiene) or poly(butyl acrylate).

8. An epoxy resin composition as described in claim 1 having a viscosity at 80° C. of 0.5 to 200 Pa·s and curable into a cured resin having a toughness of 1.3 MPa·m 0.5 or more.

9. A prepreg containing an epoxy resin composition as described in claim 1 and reinforcing fiber.

10. A fiber-reinforced composite material produced by curing a prepreg described in claim 9 .

11. A fiber-reinforced composite material containing a cured resin of an epoxy resin composition as described in claim 1 and reinforcing fiber.

12. The epoxy resin composition according to claim 1 , wherein [C1] is a bisphenol F-type epoxy resin with a number average molecular weight of about 340.

13. The epoxy resin composition according to claim 1 , wherein the modulus of the cured resin is between 4.0 Gpa and 5.0 Gpa and wherein the toughness of the cured resin is more than 1.3 MPa·m 0.5 .

14. The epoxy resin composition according to claim 1 , wherein a block copolymer of S-B-M, B-M, or M-B-M is excluded.

Assignees

• Hayashi Mami
• Fujiwara Takayuki
• Misumi Jun
• Yoshioka Kenichi
• Toray Industries

Inventors

• Hayashi Mami
• Fujiwara Takayuki
• Misumi Jun
• Yoshioka Kenichi

Classifications

• C08G59/38

  together with di-epoxy compounds · CPC title

• C08L2205/02

  containing two or more polymers of the same C08L -group · CPC title

• C08J2363/00

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

• C08L63/00 Primary

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

• C08G59/3245 Primary

  containing only nitrogen as a heteroatom · CPC title