Carbon fiber sizing agent, aqueous dispersion thereof, carbon fiber bundle applied with sizing agent, sheet-like article comprising carbon fiber bundle, and carbon fiber reinforced composite material

Patent metadata

Field	Value
Publication number	US-9862824-B2
Application number	US-201214240161-A
Country	US
Kind code	B2
Filing date	Aug 21, 2012
Priority date	Aug 22, 2011
Publication date	Jan 9, 2018
Grant date	Jan 9, 2018

Abstract

The present invention provides: a carbon fiber sizing agent that can obtain a carbon fiber bundle having a superior effect of improving mechanical properties when composited using a resin; an aqueous dispersion thereof; a carbon fiber bundle; a sheet-shaped article having a carbon fiber bundle; and a composite material. The carbon fiber sizing agent contains: a compound (A) that is an ester of an unsaturated monobasic acid and an epoxy compound having a plurality of epoxy groups in the molecule, and that has at least one epoxy group in the molecule; a urethane acrylate oligomer (B) that is bifunctional and that has a tensile elongation rate of the cured product of at least 40%; and a polyurethane resin (C) having a tensile elongation rate of a dried coating film of 350-900% inclusive. The amounts of A-C contained satisfy the conditions described in the description. The aqueous dispersion disperses the sizing agent. The carbon fiber bundle contains 0.6-3.0 mass % inclusive of the sizing agent. The sheet-shaped article and a pultruded composite material contain the carbon fiber bundle. The composite material contains the sheet-shaped article.

First claim

The invention claimed is:

1. A sizing agent for carbon fiber, comprising:
a compound (A) having at least one epoxy group in the molecule, which is an ester between an epoxy compound having plural epoxy groups in the molecule and an unsaturated monobasic acid;
a bifunctional type urethane acrylate oligomer (B) that gives a cured product having a tensile elongation of 40% or higher when measured by steps (i)-(iv):
(i) applying a mixture of 97 g of the bifunctional type urethane acrylate oligomer (B) and 3 g of 2-hydroxy-2-methyl-1-phenylpropan-1-one as a curing agent on a glass substrate;
(ii) obtaining a coating film having a thickness of 100 μm;
(iii) curing the coating film by irradiation with ultraviolet radiation for 5 seconds from a position 10 cm away from the coating film, using an ozone type lamp (80 W/cm); and
(iv) measuring tensile elongation using the cured coating film according to JIS K7127 (specimen type 5) at a tensile rate of 300 mm/min; and

a polyurethane resin (C) that produces a dried coating film having a tensile elongation of from 350% to 900% and a tensile strength of from 10 MPa to 50 MPa when measured by steps (v)-(vii):
(v) applying the polyurethane resin (C) on a glass plate;
(vi) drying the applied polyurethane resin (C) at room temperature for 15 hours;
(vii) heating at 80° C. for 6 hours;
(viii) subjecting to a heating treatment at 120° C. for 20 minutes;
(ix) obtaining a coating film having a thickness of 500 μm; and
(x) measuring tensile elongation and tensile strength according to JIS K 7127 at a tensile rate of 300 mm/min;

wherein:
the mass ratio of the content of the compound (A) and the urethane acrylate oligomer (B) is from 1/3 to 2/1 as a ratio of urethane acrylate oligomer (B)/compound (A),
the proportion of the total amount of the compound (A) and the urethane acrylate oligomer (B) in all of the sizing components is 20% by mass or more, and
the proportion of the polyurethane resin (C) in all of the sizing components is from 5% by mass to 50% by mass.

2. The sizing agent for carbon fiber according to claim 1 , wherein the polyurethane resin (C) has a glass transition temperature of from −50° C. to 35° C.

3. The sizing agent for carbon fiber according to claim 1 , further comprising an ester compound (E) having an acid value of 50 or higher and obtained from an alkylene oxide adduct of a bisphenol compound and a dicarboxylic acid compound,
wherein the content of the ester compound (E) is 2.0 times by mass or less of the total amount of the compound (A) and the urethane acrylate oligomer (B).

4. The sizing agent for carbon fiber according to claim 1 , further comprising an anionic surfactant (D-1) having an ammonium ion as a counterion and a nonionic surfactant (D-2) as surfactants (D),
wherein:
the mass ratio of the content of the anionic surfactant (D-1) and the nonionic surfactant (D-2) is in a range of from 1/10 to 1/5 as a ratio of nonionic surfactant (D-2)/anionic surfactant (D-1), and
the proportion of the total amount of the anionic surfactant (D-1) and the nonionic surfactant (D-2) in all of the sizing components is from 10% by mass to 25% by mass.

5. An aqueous dispersion of a sizing agent for carbon fiber, the aqueous dispersion comprising an aqueous dispersion in which the sizing agent for carbon fiber according to claim 1 is dispersed in water, and where an average particle size of the dispersed particles of the sizing agent in the aqueous dispersion of 0.3 μm or less.

6. The aqueous dispersion of a sizing agent for carbon fiber according to claim 5 , wherein the polyurethane resin component (C) is an aqueous dispersion of an average particle size of 0.2 μm or less.

7. A carbon fiber bundle comprising a carbon fiber applied with the sizing agent for carbon fiber according to claim 5 attached thereto, which has been treated with an aqueous dispersion of the sizing agent, wherein the amount of applied sizing agent is from 0.6% by mass to 3.0% by mass.

8. A carbon fiber bundle comprising a carbon fiber applied with the sizing agent for carbon fiber according to claim 1 attached thereto, wherein-the amount of applied sizing agent is from 0.6% by mass to 3.0% by mass.

9. The carbon fiber bundle according to claim 8 , wherein the cantilever value at 25° C. is from 200 mm to 400 mm.

10. A pultrusion molding composite material comprising the carbon fiber bundle according to claim 8 .

11. The pultrusion molding composite material according to claim 10 , comprising a thermosetting matrix resin.

12. A sheet-like article comprising the carbon fiber bundle according to claim 8 .

13. A composite material comprising the sheet-like article according to claim 12 .

14. The composite material according to claim 13 , comprising a thermosetting matrix resin.

Assignees

• Wakabayashi Kouki
• Sugiura Naoki
• Hata Masahiro
• Takeda Shigekazu
• Yoshida Keigo
• Nakamura Shuuichi
• Mitsubishi Chem Corp

Inventors

• Wakabayashi Kouki
• Sugiura Naoki
• Hata Masahiro
• Takeda Shigekazu
• Yoshida Keigo
• Nakamura Shuuichi

Classifications

• C08J2300/24

  Thermosetting resins · CPC title

• D06M13/11

  Compounds containing epoxy groups or precursors thereof · CPC title

• C08L63/00

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

• D06M15/564

  Polyureas, polyurethanes or other polymers having ureide or urethane links; Precondensation products forming them · CPC title

• D06M15/55 Primary

  Epoxy resins · CPC title