Prepreg and carbon fiber-reinforced composite material

Patent metadata

Field	Value
Publication number	US-9765194-B2
Application number	US-201314417044-A
Country	US
Kind code	B2
Filing date	Jul 16, 2013
Priority date	Jul 25, 2012
Publication date	Sep 19, 2017
Grant date	Sep 19, 2017

Abstract

A prepreg includes; sizing agent-coated carbon fibers coated with a sizing agent; and a thermosetting resin composition impregnated into the sizing agent-coated carbon fibers. The sizing agent includes an aliphatic epoxy compound (A) and an aromatic compound (B) at least containing an aromatic epoxy compound (B1). The thermosetting resin composition includes a thermosetting resin (D) and a latent hardener (E), and optionally includes an additive (F) other than the thermosetting resin (D) and the latent hardener (E). The (a)/(b) ratio is within a predetermined range where (a) is the height of a component at a binding energy assigned to CHx, C—C, and C═C and (b) is the height of a component at a binding energy assigned to C—O in a C 1s core spectrum of the surfaces of the sizing agent-coated carbon fibers analyzed by X-ray photoelectron spectroscopy.

First claim

The invention claimed is:

1. A prepreg comprising:
sizing agent-coated carbon fibers; and
a thermosetting resin composition impregnated between the sizing agent-coated carbon fibers,
wherein the sizing agent includes:
an aliphatic epoxy compound (A), and
an aromatic compound (B) at least containing an aromatic epoxy compound (B1),
the sizing agent-coated carbon fibers having an (a)/(b) ratio of 0.50 to 0.90 where (a) is a height (cps) of a component at a binding energy (284.6 eV) assigned to CHx, C—C, and C═C and (b) is a height (cps) of a component at a binding energy (286.1 eV) assigned to C—O in a C 1s core spectrum of a surface of the sizing agent applied onto the carbon fibers analyzed by X-ray photoelectron spectroscopy using AlKα 1,2 as an X-ray source at a photoelectron takeoff angle of 15°, and

wherein the thermosetting resin composition includes:
an epoxy thermosetting resin (D) with at least an epoxy resin (D1),
a latent hardener (E), resin particles (F1) insoluble in epoxy resin (D1) being a different structure from the thermosetting resin (D) and the latent hardener (E) and having a structure of General Formula (1):

(in Formula (1), R 1 and R 2 are a C 1-8 alkyl group or a halogen atom and are optionally the same as or different from each other; and R 3 is C 1-20 alkylene group), and

polyamide particles (F4) at a resin particle (F1)/polyamide particle (F4) mass ratio of 9/1 to 6/4 having a structure different from General Formula (1) and an average particle size smaller than an average particle size of the resin particles (F1),
wherein the aliphatic epoxy compound (A) and the aromatic epoxy compound (B1) are contained in a mass ratio of 52/48 to 80/20.

2. The prepreg according to claim 1 , wherein
the thermosetting resin composition is an epoxy resin composition at least containing an epoxy resin (D11) having two or more ring structures that are four- or more-membered rings and having one or two amine glycidyl groups or ether glycidyl groups that are directly bonded to at least one of the ring structures and an epoxy resin (D12) having three or more functional groups, and
the epoxy resin composition contains the epoxy resin (D11) in an amount of 5 to 60% by mass and the epoxy resin (D12) in an amount of 40 to 80% by mass relative to 100% by mass of the total epoxy resins contained.

3. The prepreg according to claim 1 , wherein the thermosetting resin composition includes a compound (E1) of General Formula (2):

(in Formula (2), R 4 to R 7 are at least one selected from the group consisting of a hydrogen atom, C 1-4 aliphatic hydrocarbon groups, alicyclic hydrocarbon groups having a carbon number of 4 or less, and halogen atoms; and X is one selected from —O—, —S—, —CO—, —C(═O)O—, and —C(═O)NH—) as the latent hardener (E).

4. The prepreg according to claim 1 , wherein
the thermosetting resin composition is an epoxy resin composition at least containing one block copolymer (F2) selected from the group consisting of S-B-M, B-M, and M-B-M,
the blocks in the block copolymer (F2) are linked through a covalent bond or linked through covalent bonds with an intermediate molecule having any chemical structure interposed therebetween,
the block M is a homopolymer of methyl methacrylate or a copolymer containing methyl methacrylate in an amount of at least 50% by mass,
the block B is incompatible with the block M and has a glass transition temperature of 20° C. or lower, and
the block S is incompatible with the blocks B and M and has a glass transition temperature higher than that of the block B.

5. The prepreg according to claim 1 , wherein
the thermosetting resin composition is an epoxy resin composition at least containing a bisphenol epoxy resin (D131) having a number average molecular weight of 1,500 or more, an amine epoxy resin (D141) having three or more functional groups, and a bisphenol epoxy resin (D151) having a number average molecular weight of 150 to 1,200, and
as for the amounts of the epoxy resins (D131), (D141), and (D151), the bisphenol epoxy resin (D131) is contained in an amount of 20 to 50 parts by mass, the amine epoxy resin (D141) is contained in an amount of 30 to 50 parts by mass, and the bisphenol epoxy resin (D151) is contained in an amount of 10 to 40 parts by mass relative to 100 parts by mass of all the epoxy resin components.

6. The prepreg according to claim 1 , wherein
the thermosetting resin composition is an epoxy resin composition at least containing an epoxy resin (D132) having a softening point of 90° C. or higher, an epoxy resin (D152) having a softening point of 50° C. or lower, an epoxy resin (D142) having a softening point of 50° C. or lower and having a solubility parameter (SP) value that is 1.2 or more larger than an SP value of the epoxy resin (D132) and an SP value of the epoxy resin (D152),
an epoxy resin hardened product obtained by hardening the epoxy resin composition has a phase separated structure including a phase rich in the epoxy resin (D132) and a phase rich in the epoxy resin (D142), and
the phase separated structure has a phase separated structure period of 1 nm to 5 μm.

7. The prepreg according to claim 1 , wherein the latent hardener (E) is an aromatic amine hardener (E2).

8. The prepreg according to claim 7 , wherein the sizing agent and the aromatic amine hardener (E2) are used in a combination where a difference between a first glass transition point of a mixture of the sizing agent and the aromatic amine hardener (E2) and a second glass transition point of the mixture is equal to or smaller than 25 degrees, the first glass transition point being determined immediately after mixing of the sizing agent and the aromatic anime hardener (E2), the second glass transition point being determined after the mixture is stored in an atmosphere of 25° C. and 60% RH for 20 days.

9. The prepreg according to claim 1 , wherein the sizing agent has an epoxy equivalent of 350 to 550 g/eq.

10. The prepreg according to claim 1 , wherein the sizing agent contains at least the aliphatic epoxy compound (A) in an amount of 35 to 65% by mass and the aromatic compound (B) in an amount of 35 to 60% by mass relative to a total amount of the sizing agent except solvents.

11. The prepreg according to claim 1 , wherein the aliphatic epoxy compound (A) is a polyether polyepoxy compound and/or a polyol polyepoxy compound having two or more epoxy groups in a molecule.

12. The prepreg according to claim 11 , wherein the aliphatic epoxy compound (A) is a glycidyl ether epoxy compound obtained by reaction of epichlorohydrin with a compound selected from ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, tetrapropylene glycol, polypropylene glycol, trimethylene glycol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, polybutylene glycol, 1,5-pentanediol, neopentyl glycol, 1,6-hexanediol, 1,4-cyclohexanedimethanol, glycerol, diglycerol, polyglycerol, trimethylolpropane, pentaerythritol, sorbitol, and arabitol.

13. The prepreg according to claim 1 , wherein the aromatic epoxy compound (B1) is a bisphenol A epoxy compound or a bisphenol F epoxy compound.

14. The prepreg according to claim 1 , wherein the sizing agent contains an ester compound (C) having no epoxy group in

Assignees

• Toray Industries

Inventors

• Arai Nobuyuki
• Ichikawa Tomoko
• Taiko Hiroshi
• Endo Makoto
• Kobayashi Masanobu
• Misumi Jun

Classifications

• D06M13/11

  Compounds containing epoxy groups or precursors thereof · CPC title

• C08K5/1515

  Three-membered rings · CPC title

• C08J5/06

  using pretreated fibrous materials · CPC title

• D06M15/55

  Epoxy resins · CPC title

• Y10T428/249944

  Fiber is precoated · CPC title