JP5777504B2 - Carbon fiber sizing agent and carbon fiber bundle treated with the sizing agent - Google Patents

Description

  The present invention relates to a carbon fiber sizing agent and a carbon fiber bundle treated with the carbon fiber sizing agent.

  Since carbon fibers are lightweight, have high strength and high elastic mechanical properties, they are used as fiber-reinforced composite materials by being combined with a matrix resin.

  Carbon fibers are usually composed of monofilaments having a diameter of several microns, but since they are brittle fibers with low elongation, fluff is likely to occur due to mechanical friction or the like, and handling is often a problem. Therefore, in order to suppress the occurrence of fluff, etc., it is generally used after sizing treatment with a sizing agent (see Patent Documents 1 and 2).

  By performing the sizing treatment with the sizing agent for carbon fiber, not only the convergence of the carbon fiber can be improved, but also the physical characteristics of the carbon fiber or the carbon fiber bundle can be improved. Further, through the sizing agent present on the surface of the carbon fiber, the compatibility with the matrix resin can be increased, and the adhesion between the matrix resin and the carbon fiber can be increased in some cases.

  The matrix resin to be combined with the carbon fiber is roughly classified into a thermosetting resin and a thermoplastic resin. When a thermoplastic resin is used as a matrix resin, it is excellent in moldability such as recycling performance as compared with a thermosetting resin, and has a high utility value because it is easy to obtain a composite material with high toughness. Therefore, composite materials using thermoplastic resins are expected to greatly increase demand in the future as structural materials for automobiles and aircraft.

  As a carbon fiber sizing agent that enhances compatibility with such a thermoplastic resin, there is an example in which water-soluble polyamide, which is a copolymer of polyamide and PEO (polyethylene oxide), has been studied (see Patent Document 3). Such a polyamide-based sizing agent for carbon fiber based on polyamide has an effect of increasing compatibility with various thermoplastic resins such as polyamide, polyester, polyethylene, and polycarbonate, and improving the convergence of carbon fiber. However, the sizing agent for carbon fiber using water-soluble polyamide found in Patent Document 3 cannot be expected to improve the physical properties of the carbon fiber bundle.

  On the other hand, carbon fiber sizing agents include a solution type such as water-soluble polyamide and an aqueous dispersion type in which a polyurethane type polymer resin is dispersed in water (see Patent Document 4). When an aqueous dispersion type is used, a film with superior heat resistance and strength is formed on the surface of the carbon fiber or the voids of the carbon fiber bundle during sizing compared to the case of using the solution type. Therefore, the physical strength of the carbon fiber or carbon fiber bundle can be improved satisfactorily. In particular, aqueous dispersions of polyamide resins are excellent in compatibility with various thermoplastic resins and can be expected to be used in a wide range of fields. However, since an aqueous dispersion of a polyamide-based resin has a problem of poor stability, various surfactants are added to improve the stability (for example, Patent Documents 5 and 6). reference). However, when an aqueous dispersion of polyamide resin added with such a surfactant is used as a sizing agent for carbon fiber, the surfactant attached to the sized carbon fiber inhibits adhesion to the matrix resin. Therefore, when a sizing treatment is performed with an aqueous dispersion of a polyamide-based resin to which a surfactant is added, there is a problem that it is difficult to obtain carbon fibers having excellent adhesion to the matrix resin.

JP 2004-360164 A JP 2006-188782 A Japanese Patent Laid-Open No. 9-3777 Japanese Patent Laid-Open No. 2-6660 Japanese translation of PCT publication No. 6-506974 Japanese Patent Laid-Open No. 2001-270987

  An object of the present invention is to provide a sizing agent for carbon fiber that can obtain a sizing carbon fiber bundle that is excellent in stability and has excellent adhesiveness with a matrix resin, such as a small change in viscosity with time. is there.

  The present inventor has intensively studied to achieve the above-described object, and the sizing agent for carbon fiber containing a polyamide and an acetylene surfactant dispersed in an aqueous medium has a small change in viscosity over time, etc. It was found that a carbon fiber bundle excellent in stationary stability and having excellent adhesion to a matrix resin when impregnated in a carbon fiber bundle was obtained, and the present invention was completed.

That is, the present invention includes a carbon fiber sizing agent described in the following section, a carbon fiber bundle treated with the carbon fiber sizing agent, and the like.
Item 1.
A sizing agent for carbon fiber, comprising an aqueous medium, a polyamide dispersed in the aqueous medium, and an acetylene surfactant.
Item 2.
The acetylene surfactant is selected from the group consisting of (i) acetylene alcohol, (ii) acetylene diol, (iii) a compound obtained by adding alkylene oxide to acetylene alcohol, and (iv) a compound obtained by adding alkylene oxide to acetylene diol. Item 2. The sizing agent for carbon fiber according to Item 1, which is at least one selected.
Item 3.
(I) Acetylene alcohol has the following formula (1):

[Wherein, R ¹ and R ² are the same or different and each represents an alkyl group having 1 to 8 carbon atoms. Item 3. A sizing agent for carbon fiber according to Item 2, which is a compound represented by the formula:
Item 4.
(Ii) Acetyrangeol is represented by the following formula (2):

[Wherein, R ³ and R ⁴ are the same or different and each represents an alkyl group having 1 to 8 carbon atoms, and R ⁵ and R ⁶ are the same or different and each represents an alkyl group having 1 to 8 carbon atoms. Item 4. A sizing agent for carbon fiber according to Item 2 or 3, which is a compound represented by the formula:
Item 5.
(Iii) A compound obtained by adding alkylene oxide to acetylene alcohol is represented by the following formula (3):

[Wherein, R ¹ and R ² are the same or different and each represents an alkyl group having 1 to 8 carbon atoms, R ⁷ represents an alkylene group having 1 to 8 carbon atoms, and i represents an integer of 1 to 10] . Item 5. A sizing agent for carbon fiber according to any one of Items 2 to 4, which is a compound represented by the formula:
Item 6.
(Iv) A compound obtained by adding an alkylene oxide to acetylene diol is represented by the following formula (4):

[Wherein, R ³ and R ⁴ are the same or different and each represents an alkyl group having 1 to 8 carbon atoms; R ⁵ and R ⁶ are the same or different and each represents an alkyl group having 1 to 8 carbon atoms; R ⁸ and R ⁹ are the same or different and each represents an alkylene group having 1 to 8 carbon atoms, j represents an integer of 1 to 10, and k represents an integer of 0 to 10. Item 6. The sizing agent for carbon fiber according to any one of Items 2 to 5, which is a compound represented by the formula:
Item 7-1.
The polyamide is at least one selected from the group consisting of a polyamide obtained by polycondensation of a diamine and a dicarboxylic acid, a polyamide obtained by polycondensation of an ω-amino-ω ′ carboxylic acid, and a polyamide obtained by ring-opening polymerization of a cyclic lactam. Item 7. A sizing agent for carbon fiber according to any one of Items 1 to 6.
Item 7-2.
_{Polyamide, - [NH (CH 2)} 5 CO] -, - [NH (CH 2) 6 NHCO (CH 2) 4 CO] -, - [NH (CH 2) 6 NHCO (CH 2) 8 CO] - ,-[NH (CH ₂ ) ₁₀ CO]-,-[NH (CH ₂ ) ₁₁ CO]-, and-[NH (CH ₂ ) ₂ NHCO-D-CO]-(wherein D has 34 carbon atoms) The sizing for carbon fibers according to Item 7-1, which is at least one selected from the group consisting of polyamides having at least one or two or more structural units selected from the group consisting of unsaturated hydrocarbons) as structural units. Agent.
Claim | item 7-3.
Polyamide is 6-nylon, 66-nylon, 610-nylon, 11-nylon, 12-nylon, 6/66 copolymer nylon, 6/610 copolymer nylon, 6/11 copolymer nylon, 6/12 copolymer nylon 6/66/11 copolymer nylon, 6/66/12 copolymer nylon, 6/66/11/12 copolymer nylon, and 6/66/610/11/12 copolymer nylon The sizing agent for carbon fiber according to Item 7-2, which is at least one kind.
Item 8.
Item 5. The sizing agent for carbon fiber according to any one of Items 1 to 7-3, wherein 0.02 to 20 parts by mass of an acetylene surfactant is contained with respect to 100 parts by mass of the polyamide.
Item 9.
Item 9. The sizing agent for carbon fiber according to any one of Items 1 to 8, further comprising a nonionic surfactant.
Item 10.
Item 10. The sizing agent for carbon fiber according to any one of Items 1 to 9, further comprising a copolymer of ethylene and ethylenically unsaturated carboxylic acid.
Item 11.
Item 11. A carbon fiber bundle treated with the sizing agent for carbon fiber according to any one of Items 1 to 10.
Item 12-1.
Item 12. A carbon fiber reinforced resin composition comprising the carbon fiber bundle according to Item 11 and a matrix resin.
Item 12-2.
Item 12. The carbon fiber reinforced resin composition according to Item 12-1, wherein the matrix resin is a thermoplastic resin.
Item 13.
The composite material obtained from the carbon fiber reinforced resin composition of claim | item 12-1 or 12-2.
Item 14.
Item 11. The method for producing a sizing agent for carbon fiber according to any one of Items 1 to 10, comprising a step of mixing an aqueous polyamide dispersion and an acetylene surfactant.
Item 15.
Item 11. A method for producing a sizing carbon fiber bundle, comprising a step of sizing a carbon fiber bundle with the sizing agent for carbon fiber according to any one of Items 1 to 10.

  The sizing agent for carbon fibers of the present invention is characterized in that an acetylene-based surfactant is contained in an aqueous dispersion in which polyamide is dispersed, and is a composition having an optimum configuration as a sizing agent for carbon fibers. For this reason, it is possible to obtain a carbon fiber bundle that is excellent in stationary stability, such as little change in viscosity over time, and excellent in adhesion to the matrix resin when impregnated in the carbon fiber bundle.

  In the carbon fiber sizing agent, once the viscosity starts to increase, it is difficult to lower the viscosity unless it is diluted with an aqueous medium to reduce the polyamide concentration in the carbon fiber sizing agent. It is important that the change in viscosity with time is small (in other words, the rate of increase in viscosity is small).

  The carbon fiber sizing agent of the present invention includes an aqueous medium, a polyamide dispersed in the aqueous medium, and an acetylene surfactant. The sizing agent for carbon fibers of the present invention can be said to be a carbon fiber sizing composition (liquid composition) or an aqueous dispersion for carbon fiber sizing.

  As the aqueous medium, water is preferable, and various kinds of water such as tap water, industrial water, ion exchange water, deionized water, and pure water can be used. Deionized water and pure water are particularly preferable. Moreover, as an aqueous medium, in the range which does not inhibit the objective of this invention, the pH adjuster, the viscosity adjuster, the fungicide, etc. were suitably added to water as needed.

  As the polyamide, a known one or one produced by a known method can be used. You may use what is marketed.

  More specifically, the polyamide used in the present invention is, for example, a method such as polycondensation of diamine and dicarboxylic acid, polycondensation of ω-amino-ω′carboxylic acid, or ring-opening polymerization of cyclic lactam. The produced polyamide is mentioned. That is, polyamides obtained by polycondensation of diamine and dicarboxylic acid, polyamides obtained by polycondensation of ω-amino-ω ′ carboxylic acid, polyamides obtained by ring-opening polymerization of cyclic lactam, and the like can be mentioned. In the polycondensation or ring-opening polymerization, a dicarboxylic acid or a monocarboxylic acid can be used as a polymerization regulator.

  Examples of the diamine include ethylenediamine, trimethylenediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, 1,7-diaminoheptane, 1,8-diaminooctane, 1,9-diaminononane, and 1,10-diaminodecane. , Phenylenediamine, metaxylylenediamine and the like.

  Examples of the dicarboxylic acid include glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, nonanedicarboxylic acid, decanedicarboxylic acid, tetradecanedicarboxylic acid, octadecanedicarboxylic acid, fumaric acid, phthalic acid, xylylene dicarboxylic acid. Acid, dimer acid (unsaturated dicarboxylic acid having 36 carbon atoms synthesized from unsaturated fatty acid mainly composed of linoleic acid or oleic acid), and the like.

  Examples of the ω-amino-ω ′ carboxylic acid include 6-aminocaproic acid, 7-aminoheptanoic acid, 9-aminononanoic acid, 11-aminoundecanoic acid, 12-aminododecanoic acid and the like.

  Examples of the cyclic lactam include ε-caprolactam, ω-enantolactam, and ω-lauryl lactam.

  The dicarboxylic acid used as the polymerization regulator is the same as the dicarboxylic acid used in the production of the polyamide. For example, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, nonanedicarboxylic acid Decanedicarboxylic acid, tetradecanedicarboxylic acid, octadecanedicarboxylic acid, fumaric acid, phthalic acid, xylylene dicarboxylic acid, dimer acid and the like. Examples of the monocarboxylic acid include caproic acid, heptanoic acid, nonanoic acid, undecanoic acid, and dodecanoic acid.

In the present invention, among polyamides, in particular, — [NH (CH ₂ ) ₅ CO] —, — [NH (CH ₂ ) ₆ NHCO (CH ₂ ) ₄ CO] —, — [NH (CH ₂ ) ₆ NHCO _{(CH 2) 8 CO] -} , - [NH (CH 2) 10 CO] -, - [NH (CH 2) 11 CO] -, and _{- [NH (CH 2) 2} NHCO-D-CO] - ( In the formula, a polyamide having at least one or two or more structural units selected from the group consisting of (C) an unsaturated hydrocarbon having 34 carbon atoms is preferably used.

  Examples of such polyamides include nylon, specifically 6-nylon, 66-nylon, 610-nylon, 11-nylon, 12-nylon, 6/66 copolymer nylon, 6/610 copolymer nylon. 6/11 copolymer nylon, 6/12 copolymer nylon, 6/66/11 copolymer nylon, 6/66/12 copolymer nylon, 6/66/11/12 copolymer nylon, or 6/66/610 / 11/12 copolymer nylon and the like. Here, “/” is a symbol used to indicate that it is a copolymer of each nylon. For example, 6/66 copolymer nylon represents a copolymer nylon of 6-nylon and 66-nylon.

  Furthermore, as an example of the polyamide used in the present invention, dimer acid-based polyamide and polyamide elastomer are also exemplified. Specific examples of the polyamide elastomer include polyamide elastomers that are a copolymer of nylon and polyester, or a copolymer of nylon and polyalkylene ether glycol. Examples of the polyalkylene ether glycol include polyethylene oxide glycol, polypropylene oxide glycol, polytetramethylene oxide glycol, polyhexamethylene oxide glycol and the like. Examples of the polyester include polyethylene terephthalate, polytrimethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polytrimethylene naphthalate, and polybutylene naphthalate.

Polyamide can be used singly or in combination of two or more. The polyamide-based elastomer is not particularly limited, but a block copolymer comprising a polyamide block and a polyether block is preferable. In particular, a block copolymer having a structure in which polyamide and polyether are copolymerized is preferable, and a block copolymer having a structure in which polyamide and polyether are copolymerized is particularly preferable. Examples of the constituent component of the polyether block include glycol compounds such as polyethylene oxide glycol, polypropylene oxide glycol, polytetramethylene oxide glycol, and polyhexamethylene oxide glycol, and diamine compounds such as polyether diamine. Two or more of these components may be used. As such a polyamide elastomer, there are several types having different molecular structures at the bonding part between the polyamide block and the polyether block, that is, bonding forms, for example, “(polyamide block) —CO—NH— (polyether block)”. Examples thereof include a polyether block amide copolymer having a bonding form, a polyether ester block amide copolymer having a bonding form of “(polyamide block) -CO—O— (polyether block)”, and the like.

  Polyamide elastomers are known or can be easily produced by known methods. For example, after reacting at least one of a lactam compound, an aminocarboxylic acid compound, and a diamine compound with a dicarboxylic acid to prepare a polyamide block substantially having both carboxyl groups at both ends, the polyamide block is coated with polyethylene oxide glycol. The method of making it react by adding and heating diamine compounds, such as glycol compounds or polyether diamine, etc. can be mentioned. Moreover, a commercial item can also be purchased and used. Examples of commercially available products include a polyether block amide copolymer (trade name “UBESTAXPA9044X2”) manufactured by Ube Industries, Ltd., and a polyether ester block amide copolymer (trade name “Pebax 2533SA01”) manufactured by Arkema. Can do.

  Although not intended to be limited in interpretation, when the polyamide-based elastomer is a block copolymer comprising a polyamide block and a polyether block, a hard polymer portion having a polyamide block (also referred to as a hard segment) And a soft polymer portion having a polyether block (also referred to as a soft segment). The hard polymer portion is crystalline and has a high melting point, and the soft polymer portion is considered to be amorphous and have a low glass transition temperature.

  As the acetylenic surfactant used in the present invention, (i) acetylene alcohol, (ii) acetylenic diol, (iii) a compound obtained by adding an alkylene oxide to acetylene alcohol, and (iv) an alkylene oxide added to acetylene diol. Compounds.

  Specifically, as (i) acetylene alcohol, the following formula (1):

[Wherein, R ¹ and R ² are the same or different and each represents an alkyl group having 1 to 8 carbon atoms. ] The compound represented by this is preferable.

  In addition, as (ii) acetylenic diol, the following formula (2):

[Wherein, R ³ and R ⁴ are the same or different and each represents an alkyl group having 1 to 8 carbon atoms, and R ⁵ and R ⁶ are the same or different and each represents an alkyl group having 1 to 8 carbon atoms. ] The compound represented by this is preferable.

  Further, (iii) as a compound obtained by adding alkylene oxide to acetylene alcohol, the following formula (3):

[Wherein, R ¹ and R ² are the same as defined above, R ⁷ represents an alkylene group having 1 to 8 carbon atoms, and i represents an integer of 1 to 10. ] The compound represented by this is preferable.

  Further, (iv) as a compound obtained by adding alkylene oxide to acetylene diol, the following formula (4):

[Wherein, R ³ and R ⁴ are the same as described above, R ⁵ and R ⁶ are the same as described above, and R ⁸ and R ⁹ are the same or different and each represents an alkylene group having 1 to 8 carbon atoms. , J represents an integer of 1 to 10, and k represents an integer of 0 to 10. ] The compound represented by this is preferable.

  In the present specification, the alkyl group having 1 to 8 carbon atoms is preferably an alkyl group having 1, 2, 3, 4, 5, 6 or 7 carbon atoms, more preferably an alkyl group having 1 to 6 carbon atoms, 1-4 alkyl groups are more preferred. The alkyl group may be linear or branched. Specifically, methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, tert-butyl, sec-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, 1-ethylpropyl, isopentyl, Examples include neopentyl, n-hexyl, 1,2,2-trimethylpropyl, 3,3-dimethylbutyl, 2-ethylbutyl, isohexyl, 3-methylpentyl group and the like.

R ¹ and R ² may be the same or different as described above. In R ¹ and R ² , the number of carbon atoms of the alkyl group represented by R ¹ is preferably equal to or less than the number of carbon atoms of the alkyl group represented by R ² . R ¹ is preferably a linear alkyl group, and R ² is preferably a branched alkyl group. Among them, R ¹ is preferably a methyl, ethyl, or propyl group, and R ² is preferably an isopropyl or isobutyl group, particularly preferably R ¹ is a methyl group and R ² is an isobutyl group.

R ³ and R ⁴ may be the same or different as described above. In R ³ and R ⁴ , the alkyl group represented by R ³ preferably has no more than the carbon number of the alkyl group represented by R ⁴ . Furthermore, R ³ is straight-chain alkyl group, it is preferred that R ⁴ is a branched chain alkyl group. Among them, R ³ is preferably an ethyl, ethyl, or propyl group, and R ⁴ is preferably an isopropyl or isobutyl group, and particularly preferably R ³ is a methyl group and R ⁴ is an isobutyl group.

R ⁵ and R ⁶ may be the same or different as described above. In R ⁵ and R ⁶ , the alkyl group represented by R ⁵ preferably has not more than the carbon number of the alkyl group represented by R ⁶ . R ⁵ is preferably a linear alkyl group, and R ⁶ is preferably a branched alkyl group. Among them, R ⁵ is preferably an ethyl, ethyl, or propyl group, and R ⁶ is preferably an isopropyl or isobutyl group, and particularly preferably R ⁵ is a methyl group and R ⁶ is an isobutyl group.

R ³ , R ⁴ , R ⁵ , and R ⁶ may be the same or different. R ³ and R ⁵ are preferably the same. R ⁴ and R ⁶ are preferably the same. Among them, it is preferable that R ³ and R ⁵ are the same and R ⁴ and R ⁶ are the same.

In the present specification, the alkylene group having 1 to 8 carbon atoms is preferably an alkylene group having 1, 2, 3, 4, 5, 6 or 7 carbon atoms, more preferably an alkylene group having 1 to 6 carbon atoms, An alkylene group having 1 to 4 carbon atoms is more preferable. The alkylene group may be linear or branched. Specifically, —CH ₂ —, — (CH ₂ ) ₂ —, — (CH ₂ ) ₃ —, — (CH ₂ ) ₄ —, — (CH ₂ ) ₅ —, — (CH ₂ ) ₆ —, _{- (CH 2) 7 -,} - (CH 2) 8 -,
-CH _(CH 3) -,
_{-CH (CH 3) CH 2 -} , - CH 2 CH (CH 3) -,
_{-CH (CH 3) CH 2 CH} 2 -, - CH 2 CH (CH 3) CH 2 -, - CH 2 CH 2 CH (CH 3) -,
_{-CH (CH 3) CH 2 CH} 2 CH 2 -, - CH 2 CH (CH 3) CH 2 CH 2 -, - CH 2 CH 2 CH (CH 3) CH 2 -, - CH 2 CH 2 CH 2 CH (CH ₃ ) −,
_{-CH (CH 3) CH 2 CH} 2 CH 2 CH 2 -, - CH 2 CH (CH 3) CH 2 CH 2 CH 2 -, - CH 2 CH 2 CH (CH 3) CH 2 CH 2 -, - CH ₂ CH ₂ CH ₂ CH (CH ₃ ) CH ₂ —, —CH ₂ CH ₂ CH ₂ CH ₂ CH (CH ₃ ) —,
_{-CH (CH 3) CH 2 CH} 2 CH 2 CH 2 CH 2 -, - CH 2 CH (CH 3) CH 2 CH 2 CH 2 CH 2 -, - CH 2 CH 2 CH (CH 3) CH 2 CH 2 _{CH 2 -, - CH 2 CH} 2 CH 2 CH (CH 3) CH 2 CH 2 -, - CH 2 CH 2 CH 2 CH 2 CH (CH 3) CH 2 -, - CH 2 CH 2 CH 2 CH 2 CH ₂ CH (CH ₃ )-,
_{-CH (CH 3) CH 2 CH} 2 CH 2 CH 2 CH 2 CH 2 -, - CH 2 CH (CH 3) CH 2 CH 2 CH 2 CH 2 CH 2 -, - CH 2 CH 2 CH (CH 3) _{CH 2 CH 2 CH 2 CH 2} -, - CH 2 CH 2 CH 2 CH (CH 3) CH 2 CH 2 CH 2 -, - CH 2 CH 2 CH 2 CH 2 CH (CH 3) CH 2 CH 2 -, _{-CH 2 CH 2 CH 2 CH 2} CH 2 CH (CH 3) CH 2 -, - CH 2 CH 2 CH 2 CH 2 CH 2 CH 2 CH (CH 3) -,
_{-CH (CH 2 CH 3) CH} 2 -, - CH 2 CH (CH 2 CH 3) -,
_{-CH (CH 2 CH 3) CH} 2 CH 2 -, - CH 2 CH (CH 2 CH 3) CH 2 -, - CH 2 CH 2 CH (CH 2 CH 3) -,
_{-CH (CH 2 CH 3) CH} 2 CH 2 CH 2 -, - CH 2 CH (CH 2 CH 3) CH 2 CH 2 -, - CH 2 CH 2 CH (CH 2 CH 3) CH 2 -, - CH _{2 CH 2 CH 2 CH (CH} 2 CH 3) -,
_{-CH (CH 2 CH 3) CH} 2 CH 2 CH 2 CH 2 -, - CH 2 CH (CH 2 CH 3) CH 2 CH 2 CH 2 -, - CH 2 CH 2 CH (CH 2 CH 3) CH 2 _{CH 2 -, - CH 2 CH} 2 CH 2 CH (CH 2 CH 3) CH 2 -, - CH 2 CH 2 CH 2 CH 2 CH (CH 2 CH 3) -,
_{-CH (CH 2 CH 3) CH} 2 CH 2 CH 2 CH 2 CH 2 -, - CH 2 CH (CH 2 CH 3) CH 2 CH 2 CH 2 CH 2 -, - CH 2 CH 2 CH (CH 2 CH _{3) CH 2 CH 2 CH 2} -, - CH 2 CH 2 CH 2 CH (CH 2 CH 3) CH 2 CH 2 -, - CH 2 CH 2 CH 2 CH 2 CH (CH 2 CH 3) CH 2 -, or _{-CH 2 CH 2 CH 2 CH 2} CH 2 CH (CH 2 CH 3) - group represented by is exemplified. In particular, a group (ethylene group) represented by — (CH ₂ ) ₂ — is preferable.

R ⁷ represents an alkylene group having 1 to 8 carbon atoms as described above. R ⁸ and R ⁹ are the same or different as described above and represent an alkylene group having 1 to 8 carbon atoms.

  i shows the integer of 1-10 (1, 2, 3, 4, 5, 6, 7, 8, 9 or 10) as above-mentioned. Preferably an integer of 1-8 is shown, more preferably an integer of 1-5 is shown, still more preferably an integer of 1-4 is shown, still more preferably an integer of 1-3 is shown, particularly preferably 1-2. Indicates an integer.

  j represents an integer of 1 to 10 (1, 2, 3, 4, 5, 6, 7, 8, 9 or 10) as described above. Preferably an integer of 1-8 is shown, more preferably an integer of 1-5 is shown, still more preferably an integer of 1-4 is shown, still more preferably an integer of 1-3 is shown, particularly preferably 1-2. Indicates an integer.

  k represents an integer of 0 to 10 (0, 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10) as described above. Preferably it represents an integer of 0 to 8, more preferably an integer of 0 to 5, more preferably an integer of 0 to 4, even more preferably an integer of 0 to 3, particularly preferably 1 to 2. Indicates an integer.

  In the above formula, j and k may be the same or different. The sum of j and k is preferably 10 or less, more preferably 9 or less, still more preferably 7 or less, still more preferably 5 or less, and particularly preferably 4 or less.

  Examples of the compound (iii) or (iv) also include compounds obtained by adding ethylene oxide and / or propylene oxide to the compound (i) or (ii), respectively.

  Such an acetylene surfactant is a known compound or can be easily produced by a known method. For example, such a compound can be obtained by a method called a Reppe reaction in which a ketone or an aldehyde is reacted with acetylene in the presence of a catalyst such as an alkali or a metal compound under pressure.

  In addition, the compounds (iii) and (iv) are respectively added to the compounds (i) or (ii) with alkylene oxide (for example, ethylene oxide and / or propylene oxide) in the presence of a catalyst such as an alkali or a metal compound. It can be obtained by polymerization.

Moreover, a commercial item can also be purchased and used for the above acetylene type surfactants. As a commercial item, the Surfynol series or Olphine series made from Aero Products (Nisshin Chemical Co., Ltd. sale) are illustrated, for example. For example, in the formula (1), a compound in which R ¹ is a methyl group and R ² is an isobutyl group is commercially available under the trade name “Surfinol 61”. In addition, in the formula (1), a compound in which R ¹ and R ² are both methyl groups is commercially available under the trade name “Orphine B”. Further, for example, in the formula (2), a compound in which R ³ and R ⁵ are both methyl groups and R ⁴ and R ⁶ are both isobutyl groups is commercially available under the trade name “Surfinol 104”. In addition, in the formula (2), compounds in which R ^{3 to} R ⁶ are all methyl groups are commercially available under the trade name “Orphine Y”. Further, Surfynol 104 added with ethylene oxide is commercially available under the trade name Surfinol 400 series. For example, an additive with 40% by weight of ethylene oxide added to Surfynol 104 is “Surfiol 104”. It is marketed under the trade name "Nol 440". Regarding Surfinol 440, when the amount of ethylene oxide added is converted to molecular weight, it is an adduct in which about 2 mol of ethylene oxide is added to about 1 mol of Surfynol 104. In Formula (4), R ⁵ and R ⁷ are It can be seen that both are methyl groups, R ⁶ and R ⁸ are both isobutyl groups, R ⁸ and R ⁹ are both ethylene groups, and j and k are both 1.

  An acetylene type surfactant can be used individually by 1 type or in combination of 2 or more types.

  The amount of the acetylene surfactant used in the present invention is preferably 0.02 to 20 parts by mass, more preferably 0.05 to 15 parts by mass, and still more preferably 100 parts by mass of the polyamide. It is 0.1-10 mass parts, More preferably, it is 0.5-10 mass parts, Most preferably, it is 1-10 mass parts. When the amount of the acetylene-based surfactant used is within the above range, the stability of the obtained carbon fiber sizing agent and the adhesion between the carbon fiber bundle obtained by the treatment with the sizing agent and the matrix resin Both can be better.

  Although a limited interpretation is not desired, the reason why the use of the acetylene surfactant in the present invention improves the stability of the sizing agent for carbon fibers and the adhesion to the matrix resin as a carbon fiber bundle. It is inferred as follows.

  That is, the amide bond in the polyamide has a large polarity, and therefore the polyamide exhibits an electrolyte behavior in the aqueous dispersion, and the polyamides tend to aggregate with each other. The triple bond in the acetylene surfactant is, It is considered that the stability of the sizing agent for carbon fibers is improved because it interacts with the amide bond in the polyamide and relaxes the tendency of the polyamides to easily aggregate. In addition, since the polyamide is less likely to aggregate in this way, it becomes easier to uniformly impregnate the carbon fiber sizing agent without forming voids or the like between the carbon fibers and the carbon fibers during the sizing treatment, and The triple bond in the acetylene-based surfactant enhances the compatibility between the polyamide and the matrix resin (that is, adhesion between molecules by hydrogen bonding), etc., and the carbon fiber bundle obtained by processing with the sizing agent is a matrix. This is considered as the reason why the adhesiveness with the resin is excellent.

  The method for producing the carbon fiber sizing agent of the present invention is not particularly limited. For example, it can be produced by a method including a step of mixing an aqueous dispersion in which polyamide is dispersed (polyamide aqueous dispersion) and an acetylene surfactant. Moreover, it can also manufacture by the method including the process of emulsifying polyamide using an acetylene-type surfactant and obtaining an aqueous dispersion.

  The method for producing the aqueous polyamide dispersion is not particularly limited as long as the polyamide can be uniformly dispersed in the aqueous medium.

  For example, a method of dispersing a polyamide powder obtained by pulverizing polyamide by, for example, a pulverization method such as a mechanical pulverization method, a freezing pulverization method, a wet pulverization method, etc. in an aqueous medium; And a method of producing an aqueous dispersion by neutralizing and self-emulsifying, a method of producing an aqueous dispersion by emulsifying polyamide using a surfactant, and the like.

  As a typical production example, a method for producing an aqueous dispersion by neutralizing a terminal carboxyl group in a polyamide with a basic substance and self-emulsifying will be described below.

  In this production method, for example, a polyamide, a basic substance, and an aqueous medium are charged into a container to prepare a mixed solution thereof.

  As a container used for preparing the mixed liquid, a pressure-resistant container provided with a heating means for heating to a temperature higher than the temperature at which the polyamide softens in an aqueous medium, and a stirring means capable of giving a shearing force to the contents Is preferred. For example, a pressure-resistant autoclave with a stirrer is preferable.

  Next, in this container, polyamide, a basic substance, and an aqueous medium are mixed and a liquid mixture is obtained. And the said liquid mixture is heated more than the softening temperature of polyamide, and is stirred and emulsified, and an emulsion is obtained. When the emulsion is cooled to room temperature, an aqueous polyamide dispersion is obtained.

  The aqueous medium is basically water, and various waters such as tap water, industrial water, ion exchange water, deionized water, and pure water can be used. Deionized water and pure water are particularly preferable. In addition, a pH adjuster, a viscosity adjuster, an antifungal agent and the like may be appropriately added to the aqueous medium as necessary within a range that does not impair the object of the present invention.

  Although it does not specifically limit as a basic substance, For example, alkali metal hydroxides, such as sodium hydroxide and potassium hydroxide, ammonia, an amine compound, etc. are mentioned. A basic substance can be used individually by 1 type or in combination of 2 or more types. Of these, sodium hydroxide and / or potassium hydroxide are particularly preferably used from the viewpoint of excellent stationary stability of the dispersion.

  The amount of the basic substance used is from 0.1 to 2 mol per mol of the terminal carboxyl group of the polyamide from the viewpoint of excellent stationary stability such as little change in the viscosity of the aqueous dispersion obtained over time. Preferably, it is 0.4-1 mol.

  The amount of polyamide used is not particularly limited, but is preferably set to 0.1 to 80 parts by mass with respect to 100 parts by mass of the obtained polyamide aqueous dispersion, and is set to 20 to 70 parts by mass. Is more preferable.

  Moreover, unless the effect of this invention is impaired, a polyamide aqueous dispersion can be obtained using a surfactant instead of a basic substance. Further, an aqueous polyamide dispersion can be obtained by using a basic substance and a surfactant in combination.

  Surfactants used to obtain an aqueous polyamide dispersion (that is, to disperse polyamide in an aqueous medium) include the above-mentioned acetylene surfactants, anionic surfactants, and nonionic surfactants. Agents.

  Examples of the anionic surfactant include aliphatic polyoxyalkylene alkyl ether sulfate, polyoxyalkylene alkylphenyl ether sulfate, alkylbenzene sulfonate, alkyl naphthalene sulfonate, alkyl diphenyl sulfonate, and α-olefin. Examples include sulfonate, alkyl sulfate ester salt, naphthalene sulfonate formalin condensate, dialkyl sulfosuccinate, polyoxyethylene alkyl ether acetate, rosinate and fatty acid salt.

  Nonionic surfactants include, for example, polyethylene glycol, ethylene oxide / propylene oxide copolymer, polyoxyethylene alkyl ether, polyoxyethylene alkyl phenyl ether, polyoxyethylene alkyl thioether, polyoxyethylene sorbitan fatty acid monoester, polyoxy Examples thereof include ethylene alkylamides and polyglycerol esters.

  Among these surfactants, nonionic surfactants are preferably used from the viewpoint of enhancing the stability of the resulting sizing agent. Among them, ethylene oxide / propylene oxide is advantageous in that the obtained sizing agent has excellent heat resistance, is not easily decomposed even when processed at a high temperature for a long time, and has good adhesion between the carbon fiber bundle treated with the sizing agent and the matrix resin. Copolymer, polyoxyethylene alkyl ether (eg, polyoxyethylene lauryl ether, polyoxyethylene tridecyl ether, polyoxyethylene cetyl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether, polyoxyethylene mysteryl ether, polyoxyethylene Oxyethylene octyldodecyl ether, etc.) are preferably used.

  The amount of the anionic surfactant and / or nonionic surfactant used is such that the total of both surfactants is preferably less than 10 parts by weight, more preferably 0.1 to 8 parts by weight, based on 100 parts by weight of the polyamide. The part is illustrated. However, since the use of these surfactants may adversely affect the adhesion between the carbon fiber bundles treated with the resulting sizing agent and the matrix resin, it should be used in a relatively large amount with reference to the above amount. It is desirable to set appropriately while avoiding.

  These surfactants may be further added after the polyamide aqueous dispersion is obtained in the process of producing the carbon fiber sizing agent.

  In addition, the carbon fiber sizing agent of the present invention includes a copolymer obtained by copolymerizing ethylene and an ethylenically unsaturated carboxylic acid (hereinafter also referred to as “copolymer of ethylene and ethylenically unsaturated carboxylic acid”). By making it, the stability as a sizing agent for carbon fibers and the adhesion between the carbon fiber bundle treated with the sizing agent and the matrix resin can be further enhanced. Examples of the copolymer of ethylene and ethylenically unsaturated carboxylic acid include a copolymer obtained by copolymerizing ethylene and ethylenically unsaturated carboxylic acid (more specifically, a random copolymer of ethylene and ethylenically unsaturated carboxylic acid). Polymers, copolymers obtained by grafting unsaturated carboxylic acids onto polyethylene, and the like. Furthermore, the copolymer etc. which added and copolymerized components other than ethylene and ethylenically unsaturated carboxylic acid are mentioned.

  Examples of the ethylenically unsaturated carboxylic acid include unsaturated carboxylic acids and dicarboxylic acids having 6 or less carbon atoms. Specific examples of the unsaturated carboxylic acid having 6 or less carbon atoms include acrylic acid, methacrylic acid, crotonic acid, and isocrotonic acid. Specific examples of the dicarboxylic acid include maleic acid and fumaric acid. , Itaconic acid and the like are exemplified. Among these, acrylic acid or methacrylic acid is preferable. In addition, ethylenically unsaturated carboxylic acid can be used 1 type or in combination of 2 or more types.

  In the copolymer of ethylene and ethylenically unsaturated carboxylic acid, the ratio of ethylene and ethylenically unsaturated carboxylic acid used as a monomer (copolymerization ratio) is not particularly limited, but the total amount of both is 100% by mass, Those having an ethylenically unsaturated carboxylic acid of about 1% by mass or more and less than about 40% by mass are suitably used. In particular, the ethylenically unsaturated carboxylic acid is more preferably about 5% by mass or more and less than about 25% by mass. If the ratio of the unsaturated carboxylic acid is not less than the lower limit of the range, the standing stability of the resulting carbon fiber sizing agent can be further improved, and the ratio of the unsaturated carboxylic acid should be less than the upper limit of the range. For example, when the carbon fiber bundle is impregnated as a carbon fiber sizing, the flexibility of the carbon fiber bundle can be further improved.

  The content of the ethylene and ethylenically unsaturated carboxylic acid copolymer is not particularly limited, but is preferably about 1 to 10 parts by mass with respect to 100 parts by mass of the total amount of polyamide. More preferably, it is about 8 parts by mass. When the content of the copolymer of ethylene and ethylenically unsaturated carboxylic acid is 1 part by mass or more, the stationary stability of the sizing agent for carbon fiber can be further improved. Moreover, when content is 10 mass parts or less, the softness | flexibility of the carbon fiber bundle obtained by processing with the sizing agent for carbon fibers can improve more.

  The copolymer of ethylene and ethylenically unsaturated carboxylic acid is preferably used as an aqueous dispersion. As a method for preparing an aqueous dispersion of a copolymer of ethylene and an ethylenically unsaturated carboxylic acid, various known methods such as a method using a surfactant, a method of self-emulsification, and a mechanical dispersion method are used. be able to.

  Examples of the surfactant used herein include the same surfactants used for producing the polyamide aqueous dispersion, and two or more of these surfactants may be used in combination. A combination of an activator and a basic substance for neutralizing the copolymer is also possible.

  In the copolymer of ethylene and ethylenically unsaturated carboxylic acid, if the copolymerization ratio of ethylenically unsaturated carboxylic acid is 10% by mass or more (that is, when the total raw material of the copolymer is 100% by mass, If the ethylenically unsaturated carboxylic acid is 10% by mass or more), a self-emulsification method can be employed. In this case, the copolymer can be dispersed by neutralizing the copolymer with a basic substance. Examples of basic substances used for neutralization include alkali metals (specifically lithium hydroxide, sodium hydroxide, potassium hydroxide, etc.), amine compounds (specifically ammonia, morpholine, triethylamine, amino alcohol, etc.) ).

  In the mechanical dispersion method, it is preferable to use a surfactant in combination, especially when the copolymerization ratio of the unsaturated carboxylic acid is about 10% by mass or less.

  The copolymer of ethylene and ethylenically unsaturated carboxylic acid is prepared by, for example, putting polyamide, a basic substance and an aqueous medium into a container (preferably a pressure vessel) in the production of the above-mentioned polyamide aqueous dispersion. When mixing, they can be added together and mixed.

  Moreover, in this invention, it can replace with the copolymer of ethylene and ethylenically unsaturated carboxylic acid, or can also use the salt of this copolymer together. For example, the copolymer ammonium salt or sodium salt obtained by self-emulsifying the copolymer using ammonia, sodium hydroxide, or the like can be used. More specifically, for example, ethylene-acrylic acid copolymer ammonium salt or sodium salt obtained by self-emulsifying ethylene-acrylic acid copolymer (copolymer of ethylene and acrylic acid) is preferably used. Can do.

  The concentration (w / w%) of the polyamide in the carbon fiber sizing agent of the present invention is desirably 0.1 to 80% by mass, and more preferably 1 to 60% by mass. When the polyamide concentration is 80% by mass or less, the stability of the sizing agent for carbon fibers can be further improved. Moreover, if the said total density | concentration is 0.1 mass% or more, it will become easier to adhere polyamide to a carbon fiber bundle.

  In the sizing agent for carbon fiber of the present invention, the average particle size of the dispersed polyamide particles is usually 0.1 to 20 μm. If the average particle size is 0.1 μm or more, the viscosity of the polyamide aqueous dispersion is less likely to be too high (if the viscosity is high, handling becomes difficult during transport, etc., and work for impregnating the carbon fiber bundle May be worse). Moreover, if it is 20 micrometers or less, the stability of an aqueous dispersion liquid can improve more. Moreover, it becomes easy to impregnate the carbon fiber bundle more uniformly. The average particle diameter is determined by a laser diffraction particle size distribution measurement method. That is, it is a value obtained when an aqueous polyamide dispersion is measured with a laser diffraction particle size distribution analyzer. Note that the particle to be measured showing the same diffraction / scattered light pattern as a sphere having a diameter of 1 μm is calculated as a particle diameter of 1 μm regardless of its shape.

  The carbon fiber sizing agent of the present invention may contain other components as long as the effects of the present invention are not impaired. For example, you may include the component generally contained in the sizing agent for carbon fibers. In addition, commercially available acetylene-based surfactants (for example, the above Surfinol series or Olphine series) may contain various organic solvents, silica powders, etc., and such commercially available acetylene-based surfactants are not included. The sizing for carbon fiber of the present invention obtained by use contains an organic solvent and silica powder, but there is no particular problem as long as the effects of the present invention are not impaired. Examples of the organic solvent include ethylene glycol, 2-ethylhexanol, isopropanol, propylene glycol, dipropylene glycol monomethyl ether and the like.

  It does not specifically limit as a carbon fiber bundle processed with the sizing agent for carbon fibers of this invention. Specific examples of carbon fibers of the carbon fiber bundle include polyacrylonitrile-based carbon fibers, rayon-based carbon fibers, lignin-based carbon fibers, pitch-based carbon fibers, vapor-grown carbon fibers, carbon nanotubes, etc. Although not particularly limited, polyacrylonitrile-based carbon fibers are preferably used in that low cost can be realized and a molded body obtained from a carbon fiber bundle obtained by bundling carbon fibers has good mechanical properties.

  The form of the carbon fiber may be any of continuous long fibers, short fibers cut from the continuous long fibers, milled yarn pulverized into a powder form, and the like. These can be variously selected depending on the application and necessary characteristics, such as a sheet shape such as a woven fabric, a knitted fabric, and a non-woven fabric.

  The carbon fiber bundle is composed of carbon fibers. A commercially available carbon fiber bundle can be used, for example. Commercially available carbon fiber bundles are usually pre-sized with an epoxy compound or the like in order to suppress fuzz and improve workability. In the present invention, these sizing agents May be used by removing the solvent by solvent washing, drying, or the like, or a commercially available carbon fiber bundle may be used as it is. Of course, a carbon fiber bundle not subjected to sizing treatment can also be used.

  The method for adhering the sizing agent for carbon fiber of the present invention to the carbon fiber bundle is not particularly limited, but in addition to the usual sizing treatment, for example, the method of dropping and spreading the sizing agent for carbon fiber on the carbon fiber bundle, the roller An immersion method, a roller contact method, or the like can also be applied. The amount of the sizing agent attached to the carbon fiber bundle can also be adjusted by adjusting the polyamide concentration, the surfactant concentration, etc. in the sizing agent. It can also be adjusted by adjusting the passage process such as a diaphragm controller.

  After adhering the sizing agent to the surface of the carbon fiber, the carbon fiber bundle (sizing carbon fiber bundle) subjected to sizing treatment with the sizing agent for carbon fiber of the present invention is obtained by subsequently removing moisture by drying treatment. . A method for the drying treatment at this time is not particularly limited, but a method using a heat medium such as hot air, a hot plate, a roller, an infrared heater or the like can be selected.

  As described above, since the sizing carbon fiber bundle of the present invention is obtained by attaching and drying the sizing agent of the present invention, the sizing carbon fiber bundle of the present invention is the sizing agent for carbon fibers of the present invention. In other words, it can be said in other words as a carbon fiber bundle to which components excluding the aqueous medium are attached.

  The amount of carbon fiber sizing agent (excluding an aqueous medium) in the sizing carbon fiber bundle treated with the carbon fiber sizing agent of the present invention is the carbon after treatment with respect to 100 parts by mass of carbon fiber before treatment. It can be represented by the increase in mass of the fiber bundle. The adhesion amount of the sizing agent for carbon fiber (excluding the aqueous medium) is desirably 0.1 to 20 parts by mass, more preferably 1 to 15 parts by mass with respect to 100 parts by mass of the carbon fiber before treatment. is there. When the adhesion amount is 20 parts by mass or less with respect to 100 parts by mass of the carbon fiber bundle, it can be expected that a more excellent opening property can be obtained. The bundle is excellent in convergence, and mechanical fuzz is less likely to occur in the processing step.

  The carbon fiber bundle (sizing carbon fiber bundle) treated with the sizing agent for carbon fibers of the present invention can be mixed with a matrix resin and used as a fiber reinforced resin composition. Therefore, this invention also includes the carbon fiber reinforced resin composition containing ((alpha)) the sizing carbon fiber bundle processed with the sizing agent of this invention, and ((beta)) matrix resin. Here, the matrix resin is not particularly limited to either a thermosetting resin or a thermoplastic resin, and may be used together, but the obtained molded product has high mechanical properties and high molding efficiency. A thermoplastic resin capable of injection molding is preferred.

  The said carbon fiber reinforced resin composition can be manufactured, for example by mixing the said ((alpha)) component and ((beta)) component. The mixing ratio is not particularly limited. For example, the component (α) is preferably about 10 to 1000 parts by mass, more preferably about 30 to 300 parts by mass with respect to 100 parts by mass of the (β) component. For mixing the (α) component and the (β) component, a known method capable of uniformly mixing them can be used. For example, a single screw extruder, a twin screw extruder, a press machine, a high-speed mixer, an injection molding machine, a drawing machine. It can carry out in accordance with a conventional method using well-known apparatuses, such as a molding machine. The carbon fiber reinforced resin composition can be obtained in various forms such as a powdery mixture of matrix resin and carbon fiber, and a granulated product made of this mixture, depending on the composition, blending method, and the like. Moreover, the molded article by the said carbon fiber reinforced resin composition can be obtained by a well-known method, for example, injection-molding the said composition in a metal mold | die. In addition, the said carbon fiber reinforced resin composition can also use another well-known additive together as needed. Specific examples of the additive include an antioxidant, a heat stabilizer, a weathering agent, a release agent and a lubricant, a pigment, a dye, a plasticizer, an antistatic agent, a flame retardant, and a reinforcing material.

  Thermoplastic resins include polyester (eg, polyethylene terephthalate, polybutylene terephthalate, etc.), polyolefin (eg, polyethylene, polypropylene, polybutylene, etc.), styrenic resin, polyoxymethylene, polyamide, polycarbonate, polymethylene methacrylate, polyvinyl chloride. And polyphenylene sulfide, polyphenylene ether, polyimide, polyamideimide, polyetherimide, polysulfone, polyethersulfone, polyketone, polyetherketone, polyetheretherketone, polyarylate, polyethernitrile, phenolphenoxy resin, fluorine resin, etc. The Further examples include thermoplastic elastomers such as polystyrene, polyolefin, polyurethane, saturated polyester, polyamide, polybutadiene, polyisoprene, and fluorine. Furthermore, these copolymers, modified products, and blends of two or more of these may be used. Here, the modified body means a derivative obtained by substituting a reactive functional group such as a carboxyl group in the molecular structure, or a derivative obtained by adding a diol such as an oxyethylene group in the molecular structure. Say.

  The sizing agent for carbon fiber of the present invention is excellent in stability, such as little change in viscosity with time, and further, adhesion between a carbon fiber bundle sized with the sizing agent (sizing carbon fiber bundle) and a matrix resin. There is also an advantage that the property is excellent. Also, because of its excellent adhesiveness, a composite material having very good mechanical properties such as strength is produced using a carbon fiber reinforced resin composition obtained by mixing the carbon fiber bundle and a matrix resin. Can do. Such a composite material is useful as a structural material for automobiles and aircraft.

  Next, examples and comparative examples in the present invention will be described, but the present invention is not limited to these.

Manufacture of sizing agent for carbon fiber
Example 1
240 g of 6/66/12 copolymer nylon (melting point: 158 ° C., terminal carboxyl group: 125 mmol / kg) as polyamide, 146 g of deionized water, 14 g of 10% aqueous sodium hydroxide solution was charged and sealed. Next, the agitator was started, and the temperature inside the autoclave was raised to 180 ° C. while stirring at a rotation speed of 1000 rpm. The mixture was stirred for an additional 30 minutes while maintaining the internal temperature at 180 ° C, then cooled, and when the internal temperature reached 90 ° C, an aqueous dispersion of ethylene-acrylic acid copolymer ammonium salt (manufactured by Sumitomo Seika Co., Ltd.) Trade name “Zyxen A”; solid content concentration 25%, acrylic acid copolymerization ratio 21.1%) 48 g and deionized water 400 g were added. Furthermore, when it cooled to room temperature and measured the average particle diameter of the polyamide in this aqueous dispersion using the diffraction type particle size distribution measuring apparatus (Shimadzu Corporation, brand name "SALD-2000J"), it was 1.5 micrometers. there were.

  Next, “Surfinol 104A” (produced by Air Products, sold by Nissin Chemical Co., Ltd., a mixture of Surfynol 104 / 2-ethylhexanol in a 50/50 weight ratio) as acetylene diol was added to the obtained aqueous polyamide dispersion. 4 .8 g was mixed to obtain a sizing agent for carbon fiber (Example 1).

Example 2
A sizing agent for carbon fiber (Example 2) was obtained in the same manner as in Example 1 except that the amount of “Surfinol 104A” used in Example 1 was changed to 0.24 g.
Example 3
A sizing agent for carbon fiber (Example 3) was obtained in the same manner as in Example 1 except that the amount of “Surfinol 104A” used was 0.96 g in Example 1.
Example 4
A sizing agent for carbon fiber (Example 4) was obtained in the same manner as in Example 1 except that the amount of “Surfinol 104A” used in Example 1 was 24 g.
Example 5
A sizing agent for carbon fiber (Example 5) was obtained in the same manner as in Example 1 except that the amount of “Surfinol 104A” used in Example 1 was changed to 48 g.
Example 6
Example 1 was the same as Example 1 except that 2.4 g of “Surfinol 61” (manufactured by Air Products, Nissin Chemical Co., Ltd.) was used as the acetylene alcohol instead of 4.8 g of “Surfinol 104A”. To obtain a carbon fiber sizing agent (Example 6).
Example 7
In Example 1, instead of 4.8 g of “Surfinol 104A”, “Surfinol 440” (manufactured by Air Products, Nissin) was added as a compound obtained by adding ethylene oxide to acetylenic diol (Surfynol 104) at a ratio of 40% by weight. (Chemical company sale) Except having used 2.4g, it operated similarly to Example 1 and obtained the sizing agent for carbon fiber (Example 7).
Example 8
In Example 1, 4.8 g of “Surfinol 104A” was mixed with the obtained aqueous polyamide dispersion, and then polyoxyethylene tridecyl ether (Daiichi Kogyo Seiyaku Co., Ltd., product, nonionic surfactant). The procedure was the same as in Example 1 except that 2.4 g of the name “Neugen TDS-70”) was mixed to obtain a sizing agent for carbon fiber (Example 8).
Example 9
In Example 1, 4.8 g of “Surfinol 104A” was mixed with the obtained aqueous polyamide dispersion, and then an ethylene oxide / propylene oxide copolymer (made by ADEKA Co., Ltd., trade name “Nonionic Surfactant”). A sizing agent for carbon fiber (Example 9) was obtained in the same manner as in Example 1 except that 2.4 g of Pluronic F108 ″) was mixed.
Comparative Example 1
A carbon fiber sizing agent (Comparative Example 1) was obtained in the same manner as in Example 1 except that “Surfinol 104A” was not used.
Comparative Example 2
In Example 1, in place of 4.8 g of “Surfinol 104A”, polyoxyethylene tridecyl ether (trade name “Neugen TDS-70” manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), which is a nonionic surfactant, A carbon fiber sizing agent (Comparative Example 2) was obtained in the same manner as in Example 1 except that 4 g was used.

  As is apparent from the production methods of the above examples, the amount of acetylene surfactant used is 1 part by mass for Examples 1, 6, 7, 8, and 9 with respect to 100 parts by mass of polyamide. Example 2 is 0.05 part by mass, Example 3 is 0.2 part by mass, Example 4 is 5 parts by mass, Example 5 is 10 parts by mass, and Comparative Examples 1 and 2 are 0 part by mass.

Stability evaluation of sizing agent for carbon fiber Each sizing agent for carbon fiber (Examples 1 to 9 and Comparative Examples 1 and 2) obtained as described above was held in a thermostat set at 25 ° C for 1 hour. After stabilization at 25 ° C., the viscosity was measured using a B-type rotary viscometer (rotation speed: 60 rpm, rotor No. 2, measurement temperature: 25 ° C.). Moreover, the average particle diameter was measured in the same manner as in Example 1 using a laser diffraction particle size distribution measuring apparatus (Shimadzu Corporation, trade name “SALD-2000J”).

Next, after storage for 1 month in a thermostat set at 25 ° C., the viscosity and average particle diameter are measured in the same manner, and the rate of increase is calculated to evaluate the stationary stability of each carbon fiber sizing agent. did.
Here, the evaluation criteria for the stationary stability evaluation are as follows.
A: Viscosity value and particle size value hardly change. (Both increase rate is less than 20%)
○: Although the viscosity value is slightly increased (increased rate is less than about 50%), the particle size value is hardly changed (increased rate is less than about 20%).
(Triangle | delta): Both a viscosity value and a particle size value are a little large. (Viscosity value increase rate 50% or more, particle size value increase rate 20% or more)
X: Viscosity value and particle size value are greatly increased. (Both increase rates are over 50%)

Examination of adhesion of carbon fiber bundle After sending out a carbon fiber bundle wound on a bobbin (trade name “Pyrofil TR50SI5L” manufactured by Mitsubishi Rayon Co., Ltd .: 15,000 filaments, filament diameter 7 μm, basis weight 1000 mg / m) from the bobbin After continuously immersing the rollers in an impregnation tank containing the sizing agents for carbon fibers (Examples 1 to 9 and Comparative Examples 1 and 2), hot air drying (190 ° C. for 5 minutes) was performed. Here, the amount of solid content of each sizing agent for carbon fiber after adjusting the squeezing after immersion and drying with hot air is 5 parts by mass with respect to the case where the mass of the carbon fiber bundle before adhesion is 100 parts by mass. It was adjusted to become.

  The obtained carbon fiber bundles were uniformly arranged on a nylon 6 sheet (area: 15 cm × 15 cm, thickness: 0.5 mm), and then the same nylon 6 sheet was placed thereon. After placing in a square mold with a thickness of 1 mm and a side length of 15 cm, press for 20 minutes (pressure against carbon fiber bundle; 19.8 Mpa) with a hydraulic press machine (manufactured by Futako Koki Co., Ltd.) set at a heating temperature of 210 ° C. By performing this, a molded body having a thickness of 1 mm was produced.

  The obtained molded body was cut to a width of 1 cm, and as a test piece, a carbon fiber bundle and a nylon 6 sheet were used under the condition of a tensile speed of 50 mm / min using an autograph (trade name “AGS-J” manufactured by Shimadzu Corporation). A 180 degree peel test of the surface was performed. Here, it was judged that the adhesive strength was excellent when the peel strength was 1.0 N / mm or more.

  The results of the above examination are shown in Table 1 below.

  From Table 1, it was found that the sizing agents for carbon fibers of Examples 1 to 9 were excellent in stability, such as little change with time in viscosity and particle diameter. Moreover, when the carbon fiber bundle was impregnated, the adhesiveness with nylon 6 as a thermoplastic resin was evaluated, but it was found that a carbon fiber bundle having excellent adhesiveness was obtained.

  On the other hand, the sizing agents for carbon fibers (Comparative Examples 1 and 2) that do not use an acetylene-based surfactant have poor stability, such as a large change with time in viscosity and particle diameter. In Comparative Example 2, a nonionic surfactant was used instead of using an acetylene surfactant, but in addition to stability, adhesion to the matrix resin was poor.

  From the above results, the sizing agent for carbon fibers of the present invention has little change in viscosity with time and is excellent in stability, and further, by treating the carbon fiber bundle with the sizing agent, the adhesion to the matrix resin is improved. It was confirmed that an excellent sizing carbon fiber bundle could be obtained.

  The carbon fiber bundle obtained in this way has a good composite strength with excellent strength because it has good adhesion to the matrix resin when it is mixed with the matrix resin to form a fiber reinforced resin composition. The material can be manufactured.

Claims (13)

A sizing agent for carbon fiber, comprising an aqueous medium, a polyamide dispersed in the aqueous medium, and an acetylene surfactant. The acetylene surfactant is selected from the group consisting of (i) acetylene alcohol, (ii) acetylene diol, (iii) a compound obtained by adding alkylene oxide to acetylene alcohol, and (iv) a compound obtained by adding alkylene oxide to acetylene diol. The sizing agent for carbon fibers according to claim 1, which is at least one selected. (I) Acetylene alcohol has the following formula (1):

[Wherein, R ¹ and R ² are the same or different and each represents an alkyl group having 1 to 8 carbon atoms. The sizing agent for carbon fibers of Claim 2 which is a compound represented by this. (Ii) Acetyrangeol is represented by the following formula (2):

[Wherein, R ³ and R ⁴ are the same or different and each represents an alkyl group having 1 to 8 carbon atoms, and R ⁵ and R ⁶ are the same or different and each represents an alkyl group having 1 to 8 carbon atoms. The sizing agent for carbon fiber of Claim 2 or 3 which is a compound represented by this. (Iii) A compound obtained by adding alkylene oxide to acetylene alcohol is represented by the following formula (3):

[Wherein, R ¹ and R ² are the same or different and each represents an alkyl group having 1 to 8 carbon atoms, R ⁷ represents an alkylene group having 1 to 8 carbon atoms, and i represents an integer of 1 to 10] . The sizing agent for carbon fiber in any one of Claims 2-4 which is a compound represented by these. (Iv) A compound obtained by adding an alkylene oxide to acetylene diol is represented by the following formula (4):

[Wherein, R ³ and R ⁴ are the same or different and each represents an alkyl group having 1 to 8 carbon atoms; R ⁵ and R ⁶ are the same or different and each represents an alkyl group having 1 to 8 carbon atoms; R ⁸ and R ⁹ are the same or different and each represents an alkylene group having 1 to 8 carbon atoms, j represents an integer of 1 to 10, and k represents an integer of 0 to 10. The sizing agent for carbon fibers according to any one of claims 2 to 5, which is a compound represented by the formula: The polyamide is at least one selected from the group consisting of a polyamide obtained by polycondensation of a diamine and a dicarboxylic acid, a polyamide obtained by polycondensation of an ω-amino-ω ′ carboxylic acid, and a polyamide obtained by ring-opening polymerization of a cyclic lactam. The sizing agent for carbon fiber in any one of Claims 1-6. The sizing agent for carbon fibers according to any one of claims 1 to 7, wherein 0.02 to 20 parts by mass of an acetylene surfactant is contained with respect to 100 parts by mass of the polyamide. The sizing agent for carbon fibers according to any one of claims 1 to 8, further comprising a nonionic surfactant. The sizing agent for carbon fibers according to any one of claims 1 to 9, further comprising a copolymer of ethylene and an ethylenically unsaturated carboxylic acid. The carbon fiber bundle processed with the sizing agent for carbon fibers in any one of Claims 1-10. A carbon fiber reinforced resin composition comprising the carbon fiber bundle according to claim 11 and a matrix resin. A composite material obtained from the carbon fiber reinforced resin composition according to claim 12.